MedWorm: Parasitology

Towards a framework for community engagement in global health research.

Trends in Parasitology — Tue, 16 Mar 2010 00:00:00 +0100

We describe here a framework that provides a starting point for broader discussions of community engagement in global health research, particularly as it relates to the development, evaluation and application of new technologies. PMID: 20299285 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

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Toxoplasma gondii: a morphometric analysis of the wall and epithelial cells of pigs intestine.

Experimental Parasitology — Sat, 13 Mar 2010 00:00:00 +0100

Authors: da Silva PD, Shiraishi CS, da Silva AV, Gonçalves GF, Sant'ana DD, de Almeida Araújo EJ The aim of this study was to perform a morphometric analysis of the different layers of the jejunal wall and epithelial cells of pigs with toxoplasmosis. Experiments were conducted using ten 88-day-old crossbred (Pietran x Wessex) pigs divided into two groups: control (n = 5) and experimental (n = 5). The experimental group consisted of animals inoculated orally with 5,000 sporulated oocysts of a genotype III strain of Toxoplasma gondii. At 30 and 60 days following inoculation, the animals were anaesthetised for jejunal biopsy. The intestinal segments were processed routinely for histology. Transverse cuts (4mum thick) were stained with haematoxylin and eosin (HE), Periodic Acid S...

Analysis of a nuclear localization signal in the p14 splicing factor in Trypanosoma cruzi.

International Journal for Parasitology — Sat, 13 Mar 2010 00:00:00 +0100

Authors: Westergaard GG, Bercovich N, Reinert MD, Vazquez MP There are only a few reported nuclear localization signals (NLS) in trypanosomes despite intensive research on nuclear metabolic processes such as mRNA processing and transcription during the recent past. Moreover, there are only two reports for a monopartite (La protein) and bipartite (H2B Histone, ESAG8) NLS in Trypanosoma brucei. We decided to investigate a NLS in Trypanosoma cruzi by selecting p14, a small RNA recognition motif (RRM) containing protein involved in the splicing process in the nucleus. Its small size (117 amino acids), and an optimized streamlined workflow for analysis in T. cruzi, allowed us to define a region of basic amino acids (RRKRRR) located at the C-terminus that is necessary for nuclear localizatio...

A putative kinase related protein (PKRP) from Plasmodium berghei mediates infection in the midgut and salivary glands of the mosquito.

International Journal for Parasitology — Thu, 11 Mar 2010 00:00:00 +0100

Authors: Purcell LA, Leitao R, Ono T, Yanow SK, Pradel G, Spithill TW, Rodriguez A The completion of the Plasmodium (malaria) life cycle in the mosquito requires the parasite to traverse first the midgut and later the salivary gland epithelium. We have identified a putative kinase related protein (PKRP) that is predicted to be an atypical protein kinase, which is conserved across many species of Plasmodium. The pkrp gene encodes a RNA of about 5,300 nucleotides that is expressed as a 90 kDa protein in sporozoites. Targeted disruption of the pkrp gene in Plasmodium berghei, a rodent model of malaria, compromises the ability of parasites to infect different tissues within the mosquito host. Early infection of mosquito midgut is reduced by 58-71%, midgut oocyst production is reduced by 50...

The development of linear regression models using environmental variables to explain the spatial distribution of Fasciola hepatica infection in dairy herds in England and Wales.

International Journal for Parasitology — Thu, 11 Mar 2010 00:00:00 +0100

Authors: M C Cann CM, Baylis M, Williams DJ Fasciolosis caused by Fasciola hepatica is a major cause of economic loss to the agricultural community worldwide as a result of morbidity and mortality in livestock. Spatial models developed with the aid of Geographic Information Systems (GIS) can be used to develop risk maps for fasciolosis for use in the formulation of disease control programmes. Here we investigate the spatial epidemiology of F. hepatica in dairy herds in England and Wales and develop linear regression models to explain observed patterns of exposure at a small spatial unit, the postcode area. Exposure data used for the analysis were taken from an earlier study of F. hepatica infection, performed in the winter of 2006/7. Climatic, environmental, soil, livestock and pasture...

Preface.

Advances in Parasitology — Wed, 10 Mar 2010 06:16:03 +0100

Authors: Rollinson D, Hay SI PMID: 20206014 [PubMed - in process] (Source: Advances in Parasitology)

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Haemonchus contortus: Cloning and characterization of serpin.

Experimental Parasitology — Sat, 06 Mar 2010 00:00:00 +0100

Authors: Yi D, Xu L, Yan R, Li X The serpin gene of Haemonchus contortus (hc-serpin) was cloned and characterized in this study. Specific primers for rapid amplification cDNA ends (RACE) were designed based on the expression sequence tag (EST, BM173953) to amplify the 3'- and 5'-ends of hc-serpin. The full length of the cDNA of this gene was obtained by overlapping the sequences of 3'- and 5'- extremities and amplification by reverse transcription-PCR. The biochemical activities of the recombinant protein (rHc-Serpin), which was expressed in prokaryotic cells and purified by affinity chromatography and size-exclusion chromatography, were analyzed by assays of trypsin inhibition, anticoagulation activity, and stability to temperature and pH. The results showed that the cloned full lengt...

Fasciola gigantica: Histology of the digestive tract and the expression of cathepsin L.

Experimental Parasitology — Sat, 06 Mar 2010 00:00:00 +0100

Authors: Meemon K, Khawsuk W, Sriburee S, Meepool A, Sethadavit M, Sansri V, Wanichanon C, Sobhon P The digestive tract of Fasciola gigantica is composed of the oral sucker, buccal tube, pharynx, esophagus, and caecum. The tegumental-type epithelium lines the first four parts of the digestive tract while the caecal-type epithelium lines the remaining parts from the caecal bifurcation. The caecal epithelial cells are classified into 3 types according to their staining properties and ultrastructural characteristics, as related to the amount of food contents in the caecal lumen. All caecal-type epithelial cells synthesize and secrete cathepsin L, a major group of enzymes in the digestive tract, as detected by in situ hybridization and immunolocalization. Moreover, the secreted cathepsin L...

Sequence-based functional annotation: what if most of the genes are unique to a genome?

Trends in Parasitology — Sat, 06 Mar 2010 00:00:00 +0100

Authors: Salavati R, Najafabadi HS The genomes of trypanosomatids are distantly related to other eukaryotes, with significant numbers of hypothetical or conserved hypothetical trypanosomatid-specific genes, whose functions cannot be determined using homology-dependent annotation methods. Here, we describe homology-independent methods to infer biological functions of genes based solely on their sequences. These approaches are not limited to trypanosomatid genomes and provide grounds for analysis of genomes of Plasmodium falciparum and other parasites associated with neglected tropical diseases. A critical evaluation of the current state of annotation of parasitic genomes endorses the need to exploit homology-independent computational methods, which can identify protein functions, potent...

The IL-12p70/IL-10 interplay is differentially regulated by free heme and hemozoin in murine bone-marrow-derived macrophages.

International Journal for Parasitology — Fri, 05 Mar 2010 00:00:00 +0100

Authors: Cambos M, Bazinet S, Abed E, Sanchez-Dardon J, Bernard C, Moreau R, M MO, Scorza T The outcome of malarial anaemia is determined by a complex interplay between pro-inflammatory and anti-inflammatory cytokines, its severity associated with accumulation of hemozoin (Hz) in macrophages, elevated IL-10 responses and impaired IL-12 production. Although free heme contributes to malarial anaemia by inducing oxidative damage of red blood cells (RBCs) and enhancing their clearance by phagocytes, its impact on IL-12/IL-10 interactions has not been fully characterized. Herein, the effect of hemin (HE) on IL-12 and IL-10 responses was studied in murine bone marrow-derived macrophages (BMDM) and compared with synthetic Hz. Our data reveal that HE induces modest inhibition of IL-12p70 respo...

Neospora caninum: Cloning and expression of a gene coding for cytokine-inducing profilin.

Experimental Parasitology — Thu, 04 Mar 2010 00:00:00 +0100

Authors: Jenkins MC, Tuo W, Feng X, Cao L, Murphy C, Fetterer R Profilins are actin-binding proteins that in T. gondii stimulate innate immunity in mice by binding Toll-like receptors (TLR) on dendritic cells (DC) leading to release of inflammatory cytokines, primarily IL-12 and IFN-gamma. The purpose of the present study was to characterize Neospora caninum profilin, termed NcProfilin. Recombinant NcProfilin was purified by affinity chromatography, and used to prepare specific antisera to allow characterization of native NcProfilin antigen in N. caninum tachyzoites. By immunoblotting, recombinant NcProfilin is 22 kDa, and is similar in size to the respective 22 kDa native protein. Immunofluorescence and immunoelectron microscopy localized native NcProfilin to the apical end of N. cani...

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The role of deer as vehicles to move ticks, Ixodes ricinus, between contrasting habitats.

International Journal for Parasitology — Thu, 04 Mar 2010 00:00:00 +0100

Authors: Ruiz-Fons F, Gilbert L In Europe the most important hosts maintaining Ixodes ricinus tick populations are deer. Therefore, excluding deer by fencing or culling are potential tick management tools. Here we test the hypothesis that deer act as vehicles for moving ticks between two distinct habitats: forest and open heather moorland. We utilised an ideal "natural experiment" whereby forests were either fenced or unfenced to prevent or allow deer to move between habitats. We aimed to test the hypothesis that deer cause a net movement of ticks from high tick density areas, i.e. forests, to low tick density areas, i.e. open moorland. We recorded I. ricinus and host abundance in 10 unfenced and seven fenced forests and their respective surrounding heather moorland. We found that fenc...

The increasing recognition of rickettsial pathogens in dogs and people.

Trends in Parasitology — Thu, 04 Mar 2010 00:00:00 +0100

Authors: Nicholson WL, Allen KE, McQuiston JH, Breitschwerdt EB, Little SE Dogs and people are exposed to and susceptible to infection by many of the same tick-borne bacterial pathogens in the order Rickettsiales, including Anaplasma phagocytophilum, Ehrlichia canis, E. chaffeensis, E. ewingii, Rickettsia rickettsii, R. conorii, and other spotted fever group rickettsiae. Recent findings include descriptions of novel Ehrlichia and Rickettsia species, recognition of the occurrence and clinical significance of co-infection, and increasing awareness of Rhipicephalus sanguineus-associated diseases. Newer molecular assays are available, although renewed efforts to encourage their use are needed. This review highlights the ecology and epidemiology of these diseases, and proposes avenues for f...

Lyme borreliosis in dogs and humans in the USA.

Trends in Parasitology — Thu, 04 Mar 2010 00:00:00 +0100

Authors: Little SE, Heise SR, Blagburn BL, Callister SM, Mead PS Borrelia burgdorferi sensu stricto is the only established etiologic agent of Lyme borreliosis in dogs and in humans in North America. Lyme borreliosis differs in dogs and humans in terms of clinical outcome following infection, diagnostic approaches, prevention strategies and treatment recommendations. Nonetheless, serologic evidence of exposure of dogs to B. burgdorferi agrees with the geographical distribution of autochthonous transmission of the agent of Lyme borreliosis, and continued monitoring of exposure rates in dogs might allow early recognition of geographic expansion of endemic areas as well as identify hyperendemic areas where both humans and dogs are at increased risk of infection. PMID: 20207198 [PubMed...

Longitudinal multi-locus molecular characterisation of sporadic Australian human clinical cases of cryptosporidiosis from 2005 to 2008.

Experimental Parasitology — Wed, 03 Mar 2010 00:00:00 +0100

Authors: Ng J, Mackenzie B, Ryan U Cryptosporidium is a gastrointestinal parasite that is recognised as a significant cause of non-viral diarrhea in both developing and industrialised countries. In the present study, a longitudinal analysis of 248 faecal specimens from Australian humans with gastrointestinal symptoms from 2005 to 2008 was conducted. Sequence analysis of the 18S rRNA gene locus and the 60 kDa glycoprotein (gp60) gene locus revealed that 195 (78.6%) of the cases were due to infection with C. hominis, 49 (19.8%) with C. parvum and four (1.6%) with C. meleagridis. A total of eight gp60 subtype families were identified; five C. hominis subtype families (Ib, Id, Ie, If and Ig), and two C. parvum subtype families (IIa and IId). The Id subtype family was the most common C. hom...

Role of Chemokines in Regulation of Immunity against Leishmaniasis.

Experimental Parasitology — Wed, 03 Mar 2010 00:00:00 +0100

Authors: Oghumu SO, Lezama-Dávila CM, Isaac-Márquez AP, Satoskar AR Successful immunity to Leishmania depends on recruitment of appropriate immune effector cells to the site of infection and chemokines play a crucial role in the process. At the same time, Leishmania parasites possess the ability to modify the chemokine profiles of their host thereby facilitating establishment of progressive infection. Therapeutic and prophylactic strategies targeted at chemokines and their receptors provide a promising area for further research. This review highlights our current knowledge concerning the role of chemokines and their receptors in modulating leishmaniasis in both clinical settings and experimental disease models. PMID: 20206625 [PubMed - as supplied by publisher] (Source: E...

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A new faecal antigen detection system for Strongyloides venezuelensis diagnosis in immunosuppressed rats.

Experimental Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

In conclusion, these results may represent a first step in the development of a rapid coproantigen detection kit for strongyloidiasis. PMID: 20206167 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Teladorsagia circumcincta: Activation-associated secreted proteins in excretory/secretory products of fourth stage larvae are targets of early IgA responses in infected sheep.

Experimental Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

Authors: Nisbet AJ, Smith SK, Armstrong S, Meikle LI, Wildblood LA, Beynon RJ, Matthews JB A detailed proteomic analysis of excreted/secretory (ES) proteins derived from fourth stage larvae (L4) of Teladorsagia circumcincta identified a number of components, including N-type and C-type single domain activation-associated secreted proteins (ASPs). Immunoblotting of L4 ES extracts with abomasal mucus derived from infected, immune sheep demonstrated the immunogenicity of some of these components, including an N-type single domain ASP, designated Tci-ASP-1. The full-length cDNA encoding this protein was isolated and sequenced. Homology searches using the inferred amino acid sequence of Tci-ASP-1 showed that it had highest identity (75% over 231 residues) to, a N-type, single domain ASP fro...

Trypanosoma cruzi: Synergistic cytotoxicity of multiple amphipathic anti-microbial peptides to T. cruzi and potential bacterial hosts.

Experimental Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

Authors: Fieck A, Hurwitz I, Kang AS, Durvasula R The parasite Trypanasoma cruzi is responsible for Chagas disease and its triatomine vector, Rhodnius prolixus, has a symbiotic relationship with the soil bacterium, Rhodococcus rhodnii. R. rhodnii that was previously genetically engineered to produce the anti-microbial peptide, cecropin A was co-infected with T. cruzi into R. prolixus resulting in clearance of the infectious T. cruzi in 65% of the vectors. Similar anti-microbial peptides have been isolated elsewhere and were studied for differential toxicity against T. cruzi and R. rhodnii. Of the six anti-microbial peptides tested, apidaecin, magainin II, melittin, and cecropin A were deemed potential candidates for the Chagas paratransgenic system as they were capable of killing T.cru...

How can tsetse population genetics contribute to African trypanosomiasis control?

Trends in Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

Authors: Solano P, Ravel S, de Meeûs T In sub-Saharan Africa, tsetse transmitted Trypanosomiases have an enormous impact on human health and economic development. Both the World Health Organisation and African countries through the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) have recently asserted their determination to rid the sub-continent of these diseases, and it is increasingly recognised that vector control should play an important role. This review mainly focuses on population genetics of tsetse of the palpalis group, the main vectors of sleeping sickness, and reports recent results on tsetse population structure and on measures of gene flow between populations. Implications of these studies for large-scale tsetse control programmes being undertaken...

Giardiasis in dogs and cats: update on epidemiology and public health significance.

Trends in Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

Authors: Ballweber LR, Xiao L, Bowman DD, Kahn G, Cama VA Molecular data have defined seven genetic Assemblages of Giardia duodenalis, named A-G. Humans are infected with Assemblages A and B, dogs primarily with C and D, and cats with F. Assemblage A has been subclassified into subtypes A-I to A-IV: A-I has been reported in humans and animals, A-II in humans, and A-III and IV exclusively in animals. Assemblage B has broad host specificity infecting humans and animals. Recently, small numbers of dogs and cats have been reported to also carry Assemblages A-I or B. Because these genotypes are found primarily in humans, and no comprehensive studies to address zoonotic transmission of G. duodenalis are yet available, the potential role of dogs and cats cannot be conclusively excluded. P...

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Toxoplasma gondii: epidemiology, feline clinical aspects, and prevention.

Trends in Parasitology — Tue, 02 Mar 2010 00:00:00 +0100

Authors: Elmore SA, Jones JL, Conrad PA, Patton S, Lindsay DS, Dubey JP Toxoplasma gondii is a parasite of birds and mammals. Cats are the only definitive host and thus the only source of infective oocysts, but other mammals and birds can develop tissue cysts. Although feline infections are typically asymptomatic, infection during human pregnancy can cause severe disease in the fetus. Cat owners can reduce their pets' exposure risk by keeping all cats indoors and not feeding them raw meat. Humans usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be...

Pyrimethamine induces oxidative stress in P. yoelii 17XL-infected mice: a novel immunomodulatory mechanism of action for an old antimalarial drug?

Experimental Parasitology — Fri, 26 Feb 2010 00:00:00 +0100

Authors: Legorreta-Herrera M, Retana-Ugalde R, Ventura-Gallegos JL, Narváez V Pyrimethamine is an antimalarial drug that has also been used successfully to treat autoimmune diseases such as lymphoproliferative syndrome. In this work, the effect of pyrimethamine (PYR) on the production of free radicals in malaria-infected mice was studied to better understand the drug's immunomodulatory properties. BALB/c and CBA/Ca mice were infected with Plasmodium yoelii 17XL. Seven days after infection, mice were treated with PYR or vehicle and sacrificed 24 hours later. Treatment with PYR increased superoxide dismutase and glutathione peroxidase activities in erythrocytes and the liver, augmented the levels of nitric oxide in the serum, and upregulated mRNA levels of superoxide dismutase, glut...

Production of recombinant proteins from protozoan parasites.

Trends in Parasitology — Fri, 26 Feb 2010 00:00:00 +0100

Authors: Fernández-Robledo JA, Vasta GR Although the past decade has witnessed sequencing from an increasing number of parasites, modern high-throughput DNA sequencing technologies have the potential to generate complete genome sequences at even higher rates. Along with the discovery of genes that might constitute potential targets for chemotherapy or vaccination, the need for novel protein expression platforms has become a pressing matter. In addition to reviewing the advantages and limitations of the currently available and emerging expression systems, we discuss novel approaches that could overcome current limitations, including the 'pseudoparasite' concept, an expression platform in which the choice of the surrogate organism is based on its phylogenetic affinity to the target ...

A natural immunization process prevents malaria.

Trends in Parasitology — Fri, 26 Feb 2010 00:00:00 +0100

Authors: Todryk SM PMID: 20189878 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

Can any lessons be learned from the ambiguous glycan binding of PfEMP1 domains?

Trends in Parasitology — Fri, 26 Feb 2010 00:00:00 +0100

Authors: Dahlbäck M, Nielsen MA, Salanti A Pregnancy-associated malaria (PAM) is caused by Plasmodium falciparum-infected erythrocytes (IEs) accumulating in the placenta and has dire consequences for both mother and child. The multi-domain antigen VAR2CSA confers specific adhesion of IEs to chondroitin sulphate A (CSA) in the placenta, and is the leading PAM vaccine candidate. Recent data from different laboratories show that the binding properties of individual VAR2CSA domains do not reflect the native CSA-specific adhesion of IEs, which questions the relevance of the information obtained from single domain binding assays and co-crystallization experiments. Here, we discuss the implications of these findings for VAR2CSA vaccine development and highlight the need for studying the ...

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Hookworms of dogs and cats as agents of cutaneous larva migrans.

Trends in Parasitology — Thu, 25 Feb 2010 00:00:00 +0100

Authors: Bowman DD, Montgomery SP, Zajac AM, Eberhard ML, Kazacos KR Dogs and cats are hosts to hookworms that may cause zoonotic disease, most notably, cutaneous larva migrans. Ancylostoma braziliense is most often implicated in dermatological lesions, and Ancylostoma caninum has been associated with eosinophilic enteritis and suggested as a possible cause of diffuse unilateral subacute neuroretinitis in humans. Other manifestations include eosinophilic pneumonitis, localized myositis, folliculitis, erythema multiforme, or ophthalmological manifestations. Ancylostoma eggs are morphologically indistinguishable, which complicates epidemiological studies. Surveys of dermatologists, gastroenterologists, and ophthalmologists would help to define the incidence of these zoonotic infections. ...

Host ontogeny and the temporal decay of similarity in parasite communities of marine fish.

International Journal for Parasitology — Tue, 23 Feb 2010 00:00:00 +0100

Authors: Timi JT, Luque JL, Poulin R Geographical distances between host populations are key determinants of how many parasite species they share. In principle, decay in similarity should also occur with increasing distance along any other dimension that characterizes some form of separation between communities. Here, we apply the biogeographical concept of distance decay in similarity to ontogenetic changes in the metazoan parasite communities of three species of marine fish from the Atlantic coast of South America. Using differences in body length between all possible pairs of size classes as measures of ontogenetic distances, we find that, using an index of similarity (Bray-Curtis) that takes into account the abundance of each parasite species, the similarity in parasite communities...

Flea-associated zoonotic diseases of cats in the USA: bartonellosis, flea-borne rickettsioses, and plague.

Trends in Parasitology — Tue, 23 Feb 2010 00:00:00 +0100

Authors: McElroy KM, Blagburn BL, Breitschwerdt EB, Mead PS, McQuiston JH Cat-scratch disease, flea-borne typhus, and plague are three flea-associated zoonoses of cats of concern in the USA. Although flea concentrations may be heaviest in coastal and temperate climates, fleas and flea-borne disease agents can occur almost anywhere in the USA. Understanding flea-borne pathogens, and the associated risks for owners and veterinarians, is important to reduce the likelihood of zoonotic infection. PMID: 20185369 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

Public health issues concerning the widespread distribution of canine heartworm disease.

Trends in Parasitology — Mon, 22 Feb 2010 00:00:00 +0100

Authors: Lee AC, Montgomery SP, Theis JH, Blagburn BL, Eberhard ML Heartworms can cause serious cardiopulmonary disease in their canid hosts. Canine heartworm has become widespread in many parts of the world, and its range continues to expand. Wildlife reservoirs play a role in perpetuation and transmission of this parasite to dogs. Human heartworm infection is incidental and is typically not associated with severe clinical disease; however, because no serological test is readily available, patients must undergo invasive procedures to differentiate heartworm from other more serious diseases. Human cases have been reported mainly in areas of high canine prevalence, highlighting the importance of heartworm testing and chemoprophylaxis in all dogs to reduce transmission. Future efforts sh...

Zoonoses of people and their pets: a US perspective on significant pet-associated parasitic diseases.

Trends in Parasitology — Mon, 22 Feb 2010 00:00:00 +0100

Authors: Paul M, King L, Carlin EP PMID: 20181531 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

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LmxMPK4, an essential mitogen-activated protein kinase of Leishmania mexicana is phosphorylated and activated by the STE7-like protein kinase LmxMKK5.

International Journal for Parasitology — Sat, 20 Feb 2010 00:00:00 +0100

Authors: Freyend SJ, Rosenqvist H, Fink A, Melzer IM, Clos J, Jensen ON, Wiese M The essential mitogen-activated protein kinase (MAP kinase), LmxMPK4, of Leishmania mexicana is minimally active when purified following recombinant expression in Escherichia coli and was therefore unsuitable for drug screening until now. Using an E. coli protein co-expression system we identified LmxMKK5, a STE7-like protein kinase from L. mexicana, which phosphorylates and activates recombinant LmxMPK4 in vitro. LmxMKK5 is comprised of 525 amino acids and has a calculated molecular mass of 55.9 kDa. The co-expressed, purified LmxMPK4 showed strong phosphotransferase activity in radiometric kinase assays and was confirmed by immunoblot and tandem mass spectrometry analyses to be phosphorylated on threonin...

Rainfall induces time-lagged changes in the proportion of tropical aquatic hosts infected with metazoan parasites.

International Journal for Parasitology — Sat, 20 Feb 2010 00:00:00 +0100

Authors: Pech D, Aguirre-Macedo ML, Lewis JW, Vidal-Martínez VM Rainfall serves as a powerful driving force, shifting temporal abundance and prevalence patterns in parasites and free-living aquatic organisms in tropical environments. However, there is a lack of sound evidence showing the temporal scales at which rainfall influences infection parameters of parasites in the tropics either directly by affecting the parasite life cycle or indirectly by modifying host population abundance. In the present study, we demonstrate that changes in rainfall patterns lead to changes in the proportion of infected hosts (PIH) with several parasite species, causing immediate or lagged favourable conditions for an increase in levels of infection. However, the temporal scale of the influence of rai...

Minimal zoonotic risk of cryptosporidiosis from pet dogs and cats.

Trends in Parasitology — Sat, 20 Feb 2010 00:00:00 +0100

Authors: Lucio-Forster A, Griffiths JK, Cama VA, Xiao L, Bowman DD The role of dogs and cats in human cryptosporidiosis has been the focus of much attention. Studies in which genotyping of Cryptospiridium oocysts in feces of dogs and cats have been successful and have demonstrated that most infections in these animals are caused by host-specific C. canis and C. felis, respectively. Most human cases of cryptosporidiosis are associated with C. hominis and C. parvum; C. canis and C. felis are responsible for only a small number of cases. Thus, molecular epidemiologic studies support the contention that the risk of zoonotic transmission of Cryptosporidium spp. from pet cats and dogs is low. Veterinarians can inform their clients of this minimal risk, but nevertheless advise them to minimiz...

Epidemiologic and zoonotic aspects of ascarid infections in dogs and cats.

Trends in Parasitology — Fri, 19 Feb 2010 00:00:00 +0100

Authors: Lee AC, Schantz PM, Kazacos KR, Montgomery SP, Bowman DD Toxocaracanis and Toxocara cati of dogs and cats, respectively, can cause significant disease in people. Human seroprevalence for Toxocara antibodies varies with factors such as geographic location, socio-economic status, and dietary habits. Risk factors for infection include geophagia and low-level education. Toxocara canis is better recognized as a cause of human toxocariasis, but Toxocara cati should not be overlooked. In addition, patent infections with Baylisascaris procyonis, the raccoon ascarid, have been increasingly recognized in dogs. Pet owners need to be properly educated about zoonotic risks, and veterinarians should institute regular parasite screening and treatment for all pets. Establishment of national s...

Three new species, Lamellodiscus tubulicornis n. sp., L. magnicornis n. sp. and L. parvicornis n. sp. (Monogenea: Diplectanidae) from Gymnocranius spp. (Lethrinidae: Monotaxinae) off New Caledonia, with the proposal of the new morphological group 'tubulicornis' within Lamellodiscus Johnston & Tiegs, 1922.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:21 +0100

Three new species, Lamellodiscus tubulicornis n. sp., L. magnicornis n. sp. and L. parvicornis n. sp. (Monogenea: Diplectanidae) from Gymnocranius spp. (Lethrinidae: Monotaxinae) off New Caledonia, with the proposal of the new morphological group 'tubulicornis' within Lamellodiscus Johnston & Tiegs, 1922. Syst Parasitol. 2010 Mar;75(3):159-79 Authors: Justine JL, Briand MJ Three new species of Lamellodiscus are described from four (including two undescribed) species of Gymnocranius off New Caledonia, South Pacific. All three species have a similar body anatomy and morphology of the haptoral hard parts and are distinguished on the basis of the male copulatory organ (MCO). Lamellodiscus tubulicornis n. sp. (type-host: G. grandoculis; other host: Gymnocranius sp. B) has an MCO...

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Caligus ignotus n. sp. (Copepoda: Caligidae) parasitic on Poey's scabbardfish Evoxymetopon poeyi (Günther) off Taiwan.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:18 +0100

Caligus ignotus n. sp. (Copepoda: Caligidae) parasitic on Poey's scabbardfish Evoxymetopon poeyi (Günther) off Taiwan. Syst Parasitol. 2010 Mar;75(3):181-6 Authors: Ho JS, Lin CL A new species of caligid copepod, Caligus ignotus n. sp., is described from Poey's scabbardfish Evoxymetopon poeyi (Günther) (Trichiuridae) caught off the southeast coast of Taiwan. The parasite was found in the gill-cavity of this benthopelagic fish. The new species is distinguished from its congeners mainly in the structure of the female genital complex (shaped like a guitar) and abdomen (with three sections and gradually broadening from anterior to posterior). This is the first report of a copepod parasite from Poey's scabbardfish. PMID: 20157793 [PubMed - in process] (Source: Systemat...

Feather mites (Astigmata: Psoroptidia) parasitising the rock ptarmigan Lagopus muta (Montin) (Aves: Galliformes) in Iceland.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:15 +0100

Authors: Mironov SV, Skirnisson K, Thorarinsdottir ST, Nielsen OK Four new species of feather mites are described from the Icelandic rock ptarmigan Lagopus muta islandorum (Faber) in Iceland. These are Metamicrolichus islandicus n. sp., Myialges borealis n. sp. (Epidermoptidae), Strelkoviacarus holoaspis n. sp. (Analgidae) and Tetraolichus lagopi n. sp. (Pterolichidae). This is the first report on feather mites associated with the Icelandic rock ptarmigan. Brief comments on the systematics and biology of corresponding feather mite genera are given. For two species, originally described in Pterolichus Robin, 1868 (Pterolichidae), new combinations are proposed, i.e. Tetraolichus gaudi (Cerný, 1971) n. comb. and T. microdiscus (Trouessart, 1887) n. comb. PMID: 20157794 [PubMed - ...

Contracaecum gibsoni n. sp. and C. overstreeti n. sp. (Nematoda: Anisakidae) from the Dalmatian pelican Pelecanus crispus (L.) in Greek waters: genetic and morphological evidence.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:13 +0100

Authors: Mattiucci S, Paoletti M, Solorzano AC, Nascetti G Two new species of Contracaecum Railliet & Henry, 1912, previously referred to as C. multipapillatum sp. A and C. multipapillatum sp. B by Nascetti et al. (1990) from the Dalmatian pelican Pelecanus crispus (L.) in the Ambracian Gulf off Greece, are described as C. gibsoni n. sp. and C. overstreeti n. sp., respectively. Morphological analysis and the differential diagnosis of genetically recognised male specimens of C. gibsoni and C. overstreeti with respect to C. multipapillatum (von Drasche, 1882) (sensu lato) from Egretta alba (L.) in northern Colombia and other morphologically related Contracaecum spp. enabled the detection of differences between the two species in a number of characters, including spicule length and th...

Isospora piacobrai n. sp. (Apicomplexa: Eimeriidae) from the masked yellowthroat Geothlypis aequinoctialis (Gmelin) (Passeriformes: Parulidae) in South America.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:10 +0100

Authors: Berto BP, Luz HR, Flausino W, Ferreira I, Lopes CW A new coccidian species (Protozoa: Apicomplexa: Eimeriidae) obtained from masked yellowthroat Geothlypis aequinoctialis (Gmelin) is reported from Brazil. Isospora piacobrai n. sp. has oöcysts which are subspheroidal to ovoidal, measure 15.8 x 10.5 mum and have a smooth, bilayered wall c. 1.2 mum thick. A micropyle and oöcyst residuum are absent, but a polar granule is present. Its sporocysts are ovoidal and measure 15.8 x 10.5 mum. The Stieda body is knob-like and prominent, the substieda body large, trapezoidal and homogeneous, and the sporocyst residuum composed of granules of different sizes. Sporozoites are vermiform with one refractile body and a nucleus. This is the first description of an isosporoid coccidian ...

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Acanthocephala: Neoechinorhynchidae) from the freshwater fish Awaous banana (Valenciennes) (Gobiidae) in Mexico.

Systematic Parasitology — Wed, 17 Feb 2010 15:16:07 +0100

Authors: Salgado-Maldonado G, Caspeta-Mandujano JM, Martínez-Ramírez E Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Eoacanthocephala: Neoechinorhynchidae) is described from the intestine of Awaous banana (Valenciennes) (Pisces: Gobiidae) collected in the Río Negro, a tributary in the upper Río Coatzacoalcos basin, Santa María Chimalapa, Oaxaca State, Mexico. It is the third species of Neoechinorhynchus Stiles & Hassall, 1905 described from Mexican freshwater fishes, although 36 other species are known from freshwater fishes in the Americas. Like four other species of Neoechinorhynchus from freshwater fishes in North America and Mexico, N. (N.) limi Muzzall & Buckner, 1982, (N.) rutili (Müller, 1780) Stiles & Hassall, 1905, N. (...

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Protein export in Plasmodium parasites: from the endoplasmic reticulum to the vacuolar export machine.

International Journal for Parasitology — Tue, 16 Feb 2010 00:00:00 +0100

Authors: Crabb BS, de Koning-Ward TF, Gilson PR It is somewhat paradoxical that the malaria parasite's survival strategy involves spending almost all of its blood-stage existence residing behind a two-membrane barrier in a host red blood cell, yet it gives considerable attention to exporting parasite-encoded proteins back across these membranes. These exported proteins are thought to play diverse roles and are crucial in pathogenic processes, such as re-modelling of the erythrocyte cytoskeleton and mediating the export of a major virulence protein known as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), and in metabolic processes such as nutrient uptake and solute exchange. Despite these varied roles most exported proteins have at least one common link; they share a traf...

Trichomonas vaginalis: Dehydroepiandrosterone sulfate and 17B-estradiol alter NTPDase activity and gene expression.

Experimental Parasitology — Sat, 13 Feb 2010 00:00:00 +0100

Authors: Rückert C, Stuepp CD, Gottardi B, Rosa J, Cisilotto J, Borges FP, Rosemberg DB, Bogo MR, Tasca T, De Carli GA, Bonan CD We investigated the effect of dehydroepiandrosterone sulfate (DHEAS) and 17beta-estradiol on NTPDase activity in fresh clinical (VP60) and long-term-grown (30236 ATCC) isolates of Trichomonas vaginalis followed by NTPDase gene transcriptional analysis. ATP hydrolysis was activated in vitro by 17beta-estradiol (0.01-1.0 muM) in the VP60 isolate. Treatment for 2 h with 17beta-estradiol (0.01-1 muM) promoted an inhibition in nucleotide hydrolysis in the 30236 isolate whereas the 12 h-treatment promoted an activation of nucleotide hydrolysis in both isolates. ADP hydrolysis was inhibited in vitro by 1.0-5.0 muM DHEAS in the ATCC isolate. The treatment with D...

Interactions of antimicrobial peptides with Leishmania and trypanosomes and their functional role in host parasitism.

Experimental Parasitology — Sat, 13 Feb 2010 00:00:00 +0100

Authors: McGwire BS, Kulkarni MM Antimicrobial peptides (AMPs) are multifunctional components of the innate systems of both insect and mammalian hosts of the pathogenic trypanosomatids Leishmania and Trypanosoma species. Structurally diverse AMPs from a wide range of organisms have been shown to have in vitro activity against these parasites acting mainly to disrupt surface-membranes. In some cases AMPs also localize intracellularly to affect calcium levels, mitochondrial function and the induction of autophagy, necrosis and apoptosis. In this review we discuss the work done in the area of AMP interactions with trypanosomatid protozoa and propose potential targets of AMP activity at the cellular level as well as how AMPs might influence parasite growth and differentiation in their host...

Giardia duodenalis: Kinetics of cyst elimination and the systemic humoral and intestinal secretory immune responses in gerbils (Meriones unguiculatus) experimentally infected.

Experimental Parasitology — Sat, 13 Feb 2010 00:00:00 +0100

In conclusion, systemic and intestinal humoral immune responses were related to the control of giardiasis in this experimental model. PMID: 20159014 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

A single parasite gene determines strain-specific protective immunity against malaria: the role of the Merozoite Surface Protein I.

International Journal for Parasitology — Thu, 11 Feb 2010 00:00:00 +0100

Authors: Cheesman S, O'Mahony E, Pattaradilokrat S, Degnan K, Knott S, Carter R Despite many decades of research, no registered vaccine against the pathogenic blood stages of the malaria parasite exists, translating into the loss of many hundreds of thousands of young lives each year in tropical Africa. Although many parasite proteins have been shown to induce immune responses in the host, proof for their induction of protective immunity is still lacking. We previously reported a novel genetic approach called linkage group selection (LGS) for rapid identification of target antigens of strain-specific protective immunity (SSPI) against malaria. In preliminary LGS experiments, we crossed two genetically distinct strains of Plasmodium chabaudi chabaudi and subjected their progeny to selec...

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Imatinib has a fatal impact on morphology, pairing stability and survival of adult Schistosoma mansoni in vitro.

International Journal for Parasitology — Mon, 08 Feb 2010 00:00:00 +0100

Authors: Beckmann S, Grevelding CG Schistosomes cause bilharzia (schistosomiasis), one of the most prevalent parasitic diseases for human and animals worldwide. Praziquantel (PZQ) is the only widely used drug for treatment and control of this parasitemia. Since a vaccine is not yet available, and in light of emerging resistance against PZQ, the search for alternatives has high priority. Here we present that Imatinib, a compound used in human cancer therapy (Gleevec; STI-571), significantly affected schistosome morphology and physiology invitro. Besides its negative effect on gonad development and pairing stability, Imatinib led to pathological alterations of the gastrodermis, which finally caused the death of the parasite. PMID: 20149792 [PubMed - as supplied by publisher] (Source:...

Australian dingoes are definitive hosts of Neospora caninum.

International Journal for Parasitology — Mon, 08 Feb 2010 00:00:00 +0100

Authors: King JS, Slapeta J, Jenkins DJ, Al-Qassab SE, Ellis JT, Windsor PA To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life-cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of N.caninum, confirmed by species-specific PCR, were shed in low numbers by one dingo pup at 12 to 14 days p.i.. The remaining animals did not shed oocysts. Furthermore, the blood from two out of three dingoes tested positive for DNA of N. caninum using PCR tests at 14 and 28 days p.i.. Oocyst shedding from the intestinal tract of a dingo ...

Eimeria acervulina: The influence of inoculation dose on transmission between broiler chickens.

Experimental Parasitology — Sun, 07 Feb 2010 00:00:00 +0100

Authors: Velkers FC, Bouma A, Graat EA, Klinkenberg D, Stegeman JA, de Jong MC The course and clinical appearance of an Eimeria species infection in chicken flocks depend on the response of an individual bird to infection and on population dynamics of the infection in the flock. Differences in ingested numbers of oocysts may affect oocyst load in the flock and the subsequent infectious dose for not yet infected birds. To study the link between numbers of oocysts excreted by infected birds and transmission of Eimeria acervulina, experiments were carried out with 42 pairs of broiler chickens using inoculation doses with 5, 50, 500 or 50,000 sporulated oocysts. In each pair one bird was inoculated and the other bird was contact-exposed. All contact birds became infected, which occurred on...

Acanthamoeba castellanii: Morphological analysis of the interaction with human cornea.

Experimental Parasitology — Sun, 07 Feb 2010 00:00:00 +0100

Authors: Omaña-Molina M, González-Robles A, Salazar-Villatoro LI, Cristóbal-Ramos AR, González-Lázaro M, Salinas-Moreno E, Méndez-Cruz R, Sánchez-Cornejo M, De la Torre-González E, Martínez-Palomo A The present study demonstrates that when Acanthamoeba castellanii trophozoites are co-cultivated with isolated human corneas, the amoeba can be invasive and cause damage to the intact corneal epithelium without the requirement of previous corneal abrasion. After adhesion, A. castellanii trophozoites migrate between cells forming bumps on the corneal cell layers and reaching Bowman s membrane in 3 h, although no evidence of cell damage was observed until the phagocytic process was detected. Likewise, conditioned medium produced damage to the corne...

Detection of matrix metallopeptidase-9-like proteins in Trypanosoma cruzi.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

In this study, the cell-associated and extracellular peptidases of T. cruzi grown in modified Roitman's complex (MRC) medium were analyzed by measuring peptidase activity in gelatin-containing zymograms. Our results showed that the cell-associated peptidases as well as peptidases extracellularly released by T. cruzi displayed two distinct proteolytic classes: cysteine and metallopeptidase activities. The major cysteine peptidase, cruzipain, synthesized by T. cruzi cells was detected in cellular parasite content, as a 50 kDa reactive polypeptide, after probing with anti-cruzipain antibody. In addition, metallo-type peptidases belonging to the matrix metallopeptidase-9 (MMP-9) family were revealed, after western blotting, as a 97 kDa protein band in cellular extract and an 85 kDa polypeptide...

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"E. histolytica: expression and localization of Gal/GalNAc lectin in virulent and nonvirulent variants from HM1:IMSS strain"

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Vancell RL, Espinosa RA, Canto AG, Avendaño MN, de León CG, Olivos-García A, Vancell DL, Pérez-Tamayo R We have purified Gal/GalNAc lectin from E. histolytica by electroelution. The purified protein was used to immunize rabbits and obtain polyclonal IgG's anti-lectin. These antibodies were used as tools to analyze the expression and localization of the amoebic lectin in both virulent (vEh) and nonvirulent (nvEh) variants of axenically cultured HM1:IMSS strain. vEh is able to induce liver abscesses in hamsters, whereas nvEh has lost this ability. In vitro, amoebic trophozoites from both variants equally express this protein as shown by densitometric analysis of the corresponding band in Western blots from lysates. In both types of trophozoites, the pattern o...

Eimeria tenella: Effects of Diclazuril Treatment on Microneme Genes Expression in Second Generation Merozoites and Pathological Changes of Caeca in Parasitized Chickens.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Zhou BH, Wang HW, Wang XY, Zhang LF, Zhang KY, Xue FQ The effects of diclazuril on mRNA expression levels of invasion-related microneme genes were examined in second generation merozoites of Eimeria tenella (E. tenella) by quantitative real-time (QRT) PCR. Diclazruil treatment of infected chickens significantly decreased the number of second generation merozoites by 65.13%, and resulted in downregulation of EtMIC genes: EtMIC1 by 65.63%, EtMIC2 by 64.12%, EtMIC3 by 56.82%, EtMIC4 by 73.48%, and EtMIC5 by 78.17%. SEM images of caecum tissue from uninfected chickens showed regular intestinal villus structure. In infected chickens, a distinct loss of the superficial epithelium, with a flattened mucosa and large-area necrosis and anabrosis, was evident. In diclazruil-treated chick...

Molecular Characterization of a Truncated Antigen (Wb14) of SXP-1 of Wuchereria bancrofti from four endemic regions in India.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Pandiaraja P, Murugan V, Hoti SL, Kaliraj P Wb14 of Wuchereria bancrofti, an orthologue of Brugia malayiSXP-1 and W. bancrofti SXP-1, was amplified from genomic DNA of W. bancrofti microfilaria collected from four distant geographical locations in India viz., Vellore, Bhubaneshwar, Pondicherry and Sevagram. The gene was sub-cloned in a prokaryotic vector pRSET and expressed in Escherichia coli as a truncated protein ( approximately 23 kDa). The nucleotide sequence of the gene is 98% similar to that of WbSXP-1 and is found to be intron-less. However, the analysis and comparison of the derived amino acid sequence with WbSXP-1 showed that Wb14 is truncated at amino acid position 153. The distribution of the two genes in the studied four geographical locations indicated that WbSXP...

Acanthamoeba castellanii: in vitro effects of selected biological, physical and chemical factors.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Chomicz L, Padzik M, Graczyk Z, Starosciak B, Graczyk TK, Naprawska A, Oledzka G, Szostakowska B Trophozoites and cysts of free-living Acanthamoebacastelanii present a serious risk to human health as causative agents of human diseases such as fatal granulomatous amoebic encephalitis and Acanthamoeba keratitis that is reported from various part of the world, also in Poland, with increasing frequency, particularly in the contact lens wearers. The amphizoic amoebae are generally extremely resistant to different chemical agents, however, several strains/isolates within Acanthamoebacastelanii may differ in virulence. Among the features considered as associated with the amoeba pathogenicity, temperature tolerance and resistance to different environmental conditions are reported. In ...

Transovarial passage of Leishmania infantum kDNA in artificially infected Rhipicephalus sanguineus.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Dantas-Torres F, Martins TF, de Paiva-Cavalcanti M, Figueredo LA, Lima BS, Brandão-Filho SP Phlebotomine sand flies are the only proven biological vectors of Leishmania parasites. However, Rhipicephalus sanguineus ticks have long been suspected to transmit Leishmania infantum in studies carried out in laboratory and natural conditions. In the present study, 5 mul of L. infantum promastigotes (1 x 10(6) cells per ml) was injected into the hemocel through the coxa I of four engorged females (F1, F2, F3 and F4). Control ticks (F5 and F6) were injected with sterile phosphate-buffered saline (PBS) using the same procedure. Then, these females, their eggs, and the originated larvae were tested by real time polymerase chain reaction (real-time PCR) for the presence of L. infantu...

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Entamoeba histolytica: molecular cloning and characterization of a novel neutral sphingomyelinase.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Mendoza-Macías CL, Barrios-Ceballos MP, Anaya-Velázquez F, Nakada-Tsukui K, Nozaki T, Padilla-Vaca F A novel neutral sphingomyelinase (nSMase) was characterized in Entamoeba histolytica trophozoites. SMase, a sphingomyelin-specific form of phospholipase C, catalyzes the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Three amoebic putative nSMase genes were found to be actively transcribed. Mg(2+)-independent nSMase activity in the soluble fraction of the trophozoites was stimulated by Mn(2+) and partially inhibited by Zn(2+). nSMase activity of the recombinant protein EhnSM1, increased 4.5-fold in the presence of 0.5 mM Mn(2+), and abolished by 5 mM Zn(2+). A dose-dependent inhibition of rEhnSM1 was observed with scyphostatin, a specific inhibitor of ...

Inflammatory changes in the central nervous system are associated with behavioral impairment in Plasmodium berghei (strain ANKA)-infected mice.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Lacerda-Queiroz N, Rodrigues DH, Vilela MC, de Miranda AS, Amaral DC, da Silva Camargos ER, de Moura Carvalho LJ, Howe CL, Teixeira MM, Teixeira AL Experimental cerebral malaria is a neuroinflammatory condition that results from the host immune response to the parasite. Using intravital microscopy, we investigated leukocyte recruitment in the brain microcirculation and the temporal relationship of this process to the behavioral changes observed in Plasmodium berghei (strain ANKA)-infected C57Bl/6 mice. We found that leukocyte recruitment was increased from day 5 post-infection (p.i.) onwards. Histopathological changes and increased levels of inflammatory cytokines in the brain were also observed. Behavioral performance evaluated by the SHIRPA protocol showed functional impairm...

Minireview: Regulation of Immunity to Plasmodium: Implications from Mouse Models for Blood Stage Malaria Vaccine Design.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

Authors: Taylor-Robinson AW Malaria, a disease caused by the protozoan parasite Plasmodium, remains a serious healthcare problem in developing countries worldwide. While the host-parasite relationship in humans has been difficult to determine, the pliability of murine malaria models has enabled valuable contributions to the understanding of the pathogenesis of disease. Although no single model reflects precisely malaria infection of the human, different models collectively provide important information on the mechanisms of protective immunity and immunopathogenesis. This review summarizes progress towards understanding the broad spectrum of immune responsiveness to the blood stages of the malaria parasite during experimental infections in mice and highlights how examination of murine m...

Trypanosoma evansi: Cholinesterase activity in acutely infected Wistar rats.

Experimental Parasitology — Thu, 04 Feb 2010 00:00:00 +0100

This study therefore, shows that reductions in the activity of cholinesterase occur in acute infection by T. evansi in rats and this demonstrates an important change occurring in animals infected by the protozoan and may indicate a potential role the enzymes play in the mechanism of disease. PMID: 20138875 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Elimination of Taenia solium transmission to pigs in a field trial of the TSOL18 vaccine in Cameroon.

International Journal for Parasitology — Tue, 02 Feb 2010 00:00:00 +0100

Authors: Assana E, Kyngdon CT, Gauci CG, Geerts S, Dorny P, Deken RD, Anderson GA, Zoli AP, Lightowlers MW A pilot field trial of the TSOL18 vaccine was undertaken in Cameroon. Two hundred and forty, 2-3 month old piglets were distributed to 114 individual households in pairs. Vaccinated animals received three immunisations with 200 mug TSOL18 plus 5 mg Quil A and 30 mg/kg oxfendazole at the time of the second immunization. Necropsies were undertaken when the pigs were approximately 12 months of age. Viable Taenia solium cysticerci were identified in 20 control pigs (prevalence 19.6%); no cysticerci were found in any of the vaccinated animals (P < 0.0001). Combined application of TSOL18 vaccination and a single oxfendazole treatment in pigs may be a relatively simple and sustainable...

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Targeting the hypnozoite reservoir of Plasmodium vivax: the hidden obstacle to malaria elimination.

Trends in Parasitology — Tue, 02 Feb 2010 00:00:00 +0100

Authors: Wells TN, Burrows JN, Baird JK Plasmodium vivax is the major species of malaria parasite outside Africa. It is especially problematic in that the infection can relapse in the absence of mosquitoes by activation of dormant hypnozoites in the liver. Medicines that target the erythrocytic stages of Plasmodium falciparum are also active against P. vivax, except where these have been compromised by resistance. However, the only clinical therapy against relapse of vivax malaria is the 8-aminoquinoline, primaquine. This molecule has the drawback of causing haemolysis in genetically sensitive patients and requires 14 days of treatment. New, safer and more-easily administered drugs are urgently needed, and this is a crucial gap in the broader malaria-elimination agenda. New development...

The demise of Leptotheca Thélohan, 1895 (Myxozoa: Myxosporea: Ceratomyxidae) and assignment of its species to Ceratomyxa Thélohan, 1892 (Myxosporea: Ceratomyxidae), Ellipsomyxa Køie, 2003 (Myxosporea: Ceratomyxidae), Myxobolus Bütschli, 1882 and Sphaerospora Thélohan, 1892 (Myxosporea: Sphaerosporidae).

Systematic Parasitology — Mon, 01 Feb 2010 00:00:00 +0100

The demise of Leptotheca Thélohan, 1895 (Myxozoa: Myxosporea: Ceratomyxidae) and assignment of its species to Ceratomyxa Thélohan, 1892 (Myxosporea: Ceratomyxidae), Ellipsomyxa Køie, 2003 (Myxosporea: Ceratomyxidae), Myxobolus Bütschli, 1882 and Sphaerospora Thélohan, 1892 (Myxosporea: Sphaerosporidae). Syst Parasitol. 2010 Feb;75(2):81-104 Authors: Gunter N, Adlard R A revision of Leptotheca Thélohan, 1895 is presented. The boundaries that separate Leptotheca from Ceratomyxa Thélohan, 1892 and Sphaerospora Thélohan, 1892 are vague and have been highlighted as an area of concern within myxosporean classification. A survey of the literature revealed 63 species that are currently assigned to Leptotheca and a further 11 species that have bee...

Nataliella marcelli n. g., n. sp. (Cestoda: Trypanorhyncha: Rhinoptericolidae) from Hawaiian fishes.

Systematic Parasitology — Mon, 01 Feb 2010 00:00:00 +0100

Authors: Palm HW A new trypanorhynch cestode from Hawaiian waters is described based on specimens in the collection of the Meguro Parasitological Museum, Tokyo, and newly collected specimens. Nataliella marcelli n. g., n. sp. is characterised by its elongate, craspedote scolex with four small, ear-shaped bothria, an elongate pars vaginalis and long bulbs. The homeoacanthous homeomorphous metabasal armature is comprised of five or six slender, solid hooks per half spiral row. A distinctive basal armature is present, including a combination of six characteristically shaped macrohooks not previously described for trypanorhynchs. The surface ultrastructure consists of gladiate spiniform microtriches that cover the distal and proximal bothrial surface and filiform microtriches on the scolex...

A new species of Calicotyle Diesing, 1850 (Monogenea: Monocotylidae) from the shortspine spurdog Squalus mitsukurii Jordan & Snyder and the synonymy of Gymnocalicotyle Nybelin, 1941 with this genus.

Systematic Parasitology — Mon, 01 Feb 2010 00:00:00 +0100

A new species of Calicotyle Diesing, 1850 (Monogenea: Monocotylidae) from the shortspine spurdog Squalus mitsukurii Jordan & Snyder and the synonymy of Gymnocalicotyle Nybelin, 1941 with this genus. Syst Parasitol. 2010 Feb;75(2):117-24 Authors: Kitamura A, Ogawa K, Shimizu T, Kurashima A, Mano N, Taniuchi T, Hirose H Calicotyle japonica n. sp., collected from the uterus, rectal gland, archinephric duct and cloaca of the shortspine spurdog Squalus mitsukurii Jordan & Snyder (Squaliformes) off the Pacific coast of Japan, is described. The new species can be distinguished from C. inermis Woolcock, 1936 by the shape of the male copulatory organ; in C. japonica this is directed anteriorly, is sharply bent in the middle and then increases in width toward the tip, whereas it ...

Five new monogenean species from the gills of Mulloidichthys vanicolensis (Perciformes: Mullidae) off New Caledonia, with the proposal of Volsellituba n. g. and Pennulituba n. g. (Monogenea: Dactylogyridae).

Systematic Parasitology — Mon, 01 Feb 2010 00:00:00 +0100

Authors: Rehulková E, Justine JL, Gelnar M Three species of Volsellituba n. g. and two species of Pennulituba n. g. are described from the gills of the yellowfin goatfish Mulloidichthys vanicolensis (Valenciennes) off New Caledonia (South Pacific). Volsellituba and Pennulituba resemble dactylogyrid genera whose species lack eye-spots and possess tandem or slightly overlapping gonads, a single prostatic reservoir, a male copulatory organ without an accessory piece, a dextroventral non-sclerotised vagina, ventral and dorsal anchor/bar complexes, and hooks with shanks comprising a single slender unit. Volsellituba n. g. is characterised by its species having ventral tegumental folds at the level of the vaginal duct, a male copulatory organ with a subterminal basal opening and a two-p...

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Three new species of Hatschekia Poche, 1902 (Copepoda: Siphonostomatoida: Hatschekiidae) parasitic on boxfishes (Pisces: Tetraodontiformes: Aracanidae and Ostraciidae) in Japanese waters.

Systematic Parasitology — Mon, 01 Feb 2010 00:00:00 +0100

Authors: Uyeno D, Nagasawa K Three new species of Hatschekia Poche, 1902 are described from the gill filaments of three species of boxfishes captured off southern Japan: H. pseudostracii n. sp. on Kentrocapros aculeatus (Houttuyn) (Aracanidae); H. bibullae n. sp. on Lactoria diaphana (Bloch & Schneider) (Ostraciidae); and H. kuroshioensis n. sp. on Tetrosomus concatenates (Bloch) (Ostraciidae). Of the 93 currently valid species in the genus, these new species differ from the 87 species which lack four stout processes on the posterior margin of the intercoxal sclerites of legs 1 and 2. Those processes are present on the remaining six species and the three new species. Of these nine species, H. pseudostracii n. sp. is distinguished by having a T-shaped chitinous frame on the cephalot...

Transmission of lungworms of harbour porpoises and harbour seals: molecular tools determine potential vertebrate intermediate hosts.

International Journal for Parasitology — Sat, 30 Jan 2010 00:00:00 +0100

Authors: Lehnert K, von Samson-Himmelstjerna G, Schaudien D, Bleidorn C, Wohlsein P, Siebert U Harbour porpoises (Phocoena phocoena) and harbour seals (Phoca vitulina) from German waters are infected by six species of lungworms (Metastrongyloidea). These nematodes parasitise the respiratory tract, are pathogenic and often cause secondary bacterial infections. In spite of their clinical and epidemiological significance, the life cycle and biology of lungworms in the marine environment is still largely unknown. Regions of ribosomal DNA (ITS-2) of all lungworms parasitizing harbour porpoises and harbour seals in German waters were sequenced to characterise and compare the different species. The phylogenetic relationship among the lungworm species was analysed by means of their ITS-2 nucle...

Identification of an abundant allergen from the sheep louse, Bovicola ovis.

International Journal for Parasitology — Sat, 30 Jan 2010 00:00:00 +0100

Authors: Pfeffer A, Shoemaker CB, Shaw RJ, Green RS, Shu D Infestation of sheep with the louse Bovicola ovis is common worldwide and leads to an allergic dermatitis referred to as 'scatter cockle'. IgE from an infested lamb was used in immunoaffinity chromatography to purify allergens from crude preparations of whole B. ovis and its faeces. SDS-PAGE of the affinity-purified eluates from both preparations showed a dominant band with M(r) of 28.5 kDa. Spleen cells from a mouse immunised with B. ovis faecal antigens were used to produce hybridomas which were screened by ELISA to identify those producing monoclonal antibodies (mAb) to the allergens purified by IgE immunoaffinity chromatography. Western blotting demonstrated that all of the mAbs examined recognised the 28.5 kDa allergen. Th...

Toxoplasma gondii: Expression of GRA1 gene in endoplasmic reticulum promotes both growth and adherence and modulates intracellular calcium release in macrophages.

Experimental Parasitology — Fri, 29 Jan 2010 00:00:00 +0100

In this study, effects of GRA1 organelle-targeted expression on macrophage functions were investigated. The recombinant plasmid pCMV/myc/ER-GRA1 was constructed and then was transfected into murine macrophage RAW264.7 by Lipofectamine, selected by resistance of G418. The selected mono-clone cell line was named ER-GRA1-RAW264.7. The expression of GRA1 was localized in ER of ER-GRA1-RAW264.7 cells by indirect immunofluorescence detection. GRA1 mRNA expression level in ER-GRA1-RAW264.7 cell was significantly enhanced with a concomitant increase in its growth and adherence activity. Fluorescence intensity of intracellular calcium in ER-GRA1-RAW264.7, ER-ctrl-RAW264.7 and RAW264.7 cells in the presence of 1 mmol/l Arachidonic Acid (AA) were assayed by confocal microscopy using calcium-sensitive...

Rejoining of Gamma-ray-induced DNA Damage in Cryptosporidium parvum Measured by the Comet Assay.

Experimental Parasitology — Thu, 28 Jan 2010 00:00:00 +0100

Authors: Lee SU, Joung M, Nam T, Park WY, Yu JR Cryptosporidium parvum is a well-known waterborne intracellular protozoan that causes severe diarrheal illness in immunocompromised individuals. This organism is highly resistant to harsh environmental conditions and various disinfectants, and it exhibits one of the highest known resistances to gamma irradiation. We investigated rejoining of gamma-ray-induced DNA damage in C. parvum by neutral comet assay. Oocysts were gamma irradiated at various doses (1, 5, 10, and 25 kGy) and were incubated for various periods (6-96 h) after exposure to 10 kGy. The comet tail moment showed that the number of DNA double-strand breaks increased concomitantly with the gamma irradiation dose. When investigating rejoining after irradiation at 10 kGy, double...

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Free-living amoebae isolated from water-hyacinth root (Eichhorniacrassipes).

Experimental Parasitology — Thu, 28 Jan 2010 00:00:00 +0100

Authors: Ramirez E, Robles E, Martinez B Free-living amoebae are widely distributed in aquatic environments and their hygienic, medical and ecological relationships to man are increasingly important. The purpose of this study was to isolate free-living amoebae from water-hyacinth root (Eichhorniacrassipes) and the water of an urban lake in Mexico City. Five grams of wet root were seeded on non-nutritive agar with Enterobacter aerogenes (NNE). Water samples were concentrated by centrifugation at 1,200 g for 15 min. and the pellet was seeded on NNE. Of the 16 isolated genera, 10 were detected in both habitats. The most frequent were Vannella in root and Acanthamoeba and Naegleria in water. The total number of isolates and genera isolated from root was higher than that isolated from water...

Absence of mitogen-activated protein kinase family member c-Jun N-terminal kinase-2 enhances resistance to Toxoplasma gondii.

Experimental Parasitology — Thu, 28 Jan 2010 00:00:00 +0100

Authors: Sukhumavasi W, Warren AL, Alonso LD, Denkers EY The function of mitogen-activated protein kinase (MAPK) family member c-Jun N-terminal kinase (JNK)-2 in resistance and pathology during infection has not been greatly studied. Here, we employed Jnk2(-/-) mice to investigate the role of JNK2 in resistance and immunity during oral infection with the protozoan pathogen Toxoplasma gondii. We found increased host resistance in the absence of JNK2 as determined by lower parasite burden and increased host survival. Lack of JNK2 also correlated with decreased neutrophil recruitment to the intestinal mucosa and less pathology in the small intestine. In the absence of JNK2, IL-12 production was slightly but significantly increased in restimulated splenocyte populations as well as in purif...

Trypanosoma brucei: Reduction of GPI-phospholipase C Protein During Differentiation is Dependent on Replication of Newly-Transformed Cells.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Subramanya S, Armah DA, Mensa-Wilmot K The protozoan parasite Trypanosoma brucei lives in the bloodstream of vertebrates or in a tsetse fly. Expression of a GPI-phospholipase C polypeptide (GPI-PLCp) in the parasite is restricted to the bloodstream form. Events controlling the amount of GPI-PLCp expressed during differentiation are not completely understood. Our metabolic "pulse-chase" analysis reveals that GPI-PLCp is stable in bloodstream form. However, during differentiation of bloodstream to insect stage (procyclic) T. brucei, translation GPI-PLC mRNA ceases within 8 h of initiating transformation. GPI-PLCp is not lost precipitously from newly-transformed procyclic trypanosomes. Nascent procyclics contain 400-fold more GPI-PLCp than established insect stage T. brucei. Redu...

Activation of Leishmania (Leishmania) amazonensis arginase at low temperature by binuclear Mn(2+) center formation of the immobilized enzyme on a Ni(2+) resin.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Silva ER, Floeter-Winter LM In Leishmania, arginase is responsible for the production of ornithine, a precursor of polyamines required for proliferation of the parasite. In this work, the activation kinetics of immobilized arginase enzyme from L. (L.) amazonensis were studied by varying the concentration of Mn(2+) applied to the nickel column at 23 C. The intensity of the binding of the enzyme to the Ni(2+) resin was directly proportional to the concentration of Mn(2+). Conformational changes of the enzyme may occur when the enzyme interacts with immobilized Ni(2+), allowing the following to occur: 1) entrance of Mn(2+) and formation of the metal bridge; 2) stabilization and activation of the enzyme at 23 C; and 3) an increase in the affinity of the enzyme to Ni(2+) after the ...

Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Wang YN, Wang M, Field MC In Trypanosoma brucei the GPI-anchored variant surface glycoprotein (VSG) represents approximately 90% of cell surface protein and a major proportion of endoplasmic reticulum (ER) biosynthetic output. We identified four trypanosomatid-specific genes encoding candidate ER-resident proteins; all were required for normal proliferation. For Tb11.01.2640 and Tb11.01.8120, an increase in VSG abundance was found on silencing, while the protein products localized to the ER; we designated these ERAP32 and ERAP18 for ER-associated protein of 32kDa and 18kDa. Silencing ERAP32 or ERAP18 did not alter expression levels of ISG65 or ISG75, the major surface trans-membrane domain proteins. Surface biotinylation or immunoflorescence did not identify intracellular VSG ...

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Acanthamoeba spp.: Efficacy of Bioclen FR One Step(R), a Povidone-Iodine Based System for the Disinfection of Contact Lenses.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

In this study, Bioclen FR One Step(R) was tested against three clinical Acanthamoeba isolates from contact lens cases. The results demonstrated that the tested Acanthamoeba clinical strains were sensitive to Bioclen FR One Step(R). PMID: 20109451 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Inhibitory effect of ursolic acid derivatives on hydrogen peroxide- and glutathione-mediated degradation of hemin : a possible additional mechanism of action for antimalarial activity.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Mullié C, Jonet A, Dassonville-Klimpt A, Gosmann G, Sonnet P Compounds obtained by the condensation of ursolic acid (UA) with 1,4-bis(3-aminopropyl)piperazines have previously been shown as cytocidal to Plasmodium falciparum strains. Preliminary results indicated that the inhibition of beta-hematin formation (one of the possible mechanisms of action of antimalarial drugs) was achieved by a few of these molecules with varying efficiencies. To gain further insight in the antimalarial action of UA derivatives, we report here the results of additional pathways that may explain their in vitro cytocidal activity such as inhibition of hemin degradation by H(2)O(2) or glutathione (GSH). H(2)O(2)-mediated hemin degradation was drastically reduced by hydroxybenzyl-substituted UA de...

Conservation of protein kinase a catalytic subunit sequences in the schistosome pathogens of humans.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

We report the identification of PKA-C subunit orthologues in S. haematobium and S. japonicum (ShPKA-C and SjPKA-C respectively) and show that PKA-C orthologues are highly conserved in the Schistosoma, with over 99 % amino acid sequence identity shared among the three human pathogens we examined. Furthermore, we show that the recently published S. mansoni and S. japonicum genomes contain sequences encoding for several putative PKA substrates with homology to those found in Homo sapiens, Caenorhabditis elegans, and Saccharomyces cerevisiae. PMID: 20109453 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Loop-mediated Isothermal Amplification (LAMP) test for detection of Trypanosoma evansi strain B.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Njiru ZK, Ouma JO, Enyaru JC, Dargantes AP Camel Trypanosomiasis (Surra) is mainly caused by Trypanosoma evansi strains that express variable surface glycoprotein (VSG) RoTat 1.2. However, in Kenya a second causative strain that does not express RoTat 1.2 VSG (Trypanosoma evansi type B) has been identified. The prevalence of T. evansi type B largely remains unknown due to inadequate diagnostic assay. This work reports the development of a sensitive and specific diagnostic assay capable of detecting T. evansi type B based on the strategy of Loop-mediated Isothermal Amplification (LAMP) of DNA. The test is rapid and amplification is achieved within 20-25 minutes at 63(o)C using a real time PCR machine. Restriction enzyme AluI digestion of the amplicon gave the predicted 83 bp an...

Cattle nematodes resistant to macrocyclic lactones: comparative effects of P-glycoprotein modulation on the efficacy and disposition kinetics of ivermectin and moxidectin.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Lifschitz A, Suarez VH, Sallovitz J, Cristel SL, Imperiale F, Ahoussou S, Schiavi C, Lanusse C The role of the drug efflux pump, known as P-glycoprotein, in the pharmacokinetic disposition (host) and resistance mechanisms (target parasites) of the macrocyclic lactone (ML) antiparasitic compounds has been demonstrated. To achieve a deeper comprehension on the relationship between their pharmacokinetic and pharmacodynamic behaviors, the aim of the current work was to assess the comparative effect of loperamide, a well-established P-glycoprotein modulator, on the ivermectin and moxidectin disposition kinetics and efficacy against resistant nematodes in cattle. Fifty (50) Aberdeen Angus male calves were divided into five (5) experimental groups. Group A remained as an untreated co...

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Identification of rare and novel Cryptosporidium GP60 subtypes in human isolates from Jordan.

Experimental Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Hijjawi N, Ng J, Yang R, Atoum MF, Ryan U Little is known about the epidemiology of Cryptosporidium in Jordan and no genotyping studies have been conducted on Cryptosporidium isolates from humans or animals from Jordan. Genotyping of 44 Cryptosporidium isolates from Jordanian children at the 18S rRNA locus and a unique diagnostic locus identified 4 Cryptosporidium species; C. parvum (22), C. hominis (20), C. meleagridis (1) and C. canis (1). Sub-genotype analysis of 29 isolates at the 60-kDa glycoprotein (GP60) locus identified three C. parvum, two C. hominis subtype families and 1 C. meleagridis subtype. Several rare and novel subtypes were identified indicating unique endemicity and transmission of Cryptosporidium in Jordan. PMID: 20109456 [PubMed - as supplied by publis...

Local immune response against larvae of Rhipicephalus (Boophilus) microplus in Bos taurus indicus and Bos taurus taurus cattle.

International Journal for Parasitology — Mon, 25 Jan 2010 00:00:00 +0100

Authors: Constantinoiu CC, Jackson LA, Jorgensen WK, Lew-Tabor AE, Piper EK, Mayer DG, Venus B, Jonsson NN Bos taurus indicus cattle are less susceptible to infestation with Rhipicephalus (Boophilus) microplus than Bos taurus taurus cattle but the immunological basis of this difference is not understood. We compared the dynamics of leukocyte infiltrations (T cell subsets, B cells, major histocompatibility complex (MHC) class II-expressing cells, granulocytes) in the skin near the mouthparts of larvae of R. microplus in B. t. indicus and B. t. taurus cattle. Previously naïve cattle were infested with 50,000 larvae (B. t. indicus) or 10,000 larvae (B. t. taurus) weekly for 6 weeks. One week after the last infestation all of the animals were infested with 20,000 larvae of R. microplu...

Additive effects of plant expressed double-stranded RNAs on root-knot nematode development.

International Journal for Parasitology — Fri, 22 Jan 2010 00:00:00 +0100

Authors: Charlton WL, Harel HY, Bakhetia M, Hibbard JK, Atkinson HJ, McPherson MJ Ectopically expressed double-stranded RNAs (dsRNAs) have recently been shown to suppress parasitic success of Meloidogyne spp. in plants. We have targeted two genes from the root-knot nematode Meloidogyne incognita; a dual oxidase gene implicated in the tyrosine cross-linking of the developing cuticle and a subunit of signal peptidase, a protein complex required for the processing of secreted proteins. While these genes are involved in different aspects of nematode development, the phenotypic consequences of RNA interference (RNAi) were similar with 50% reduction in nematode numbers in the roots and retardation of development to the egg-producing saccate females. Expression of processed dsRNA was observed...

Neospora caninum: Application of apical membrane antigen 1 encapsulated in the oligomannose-coated liposomes for reduction of offspring mortality from infection in BALB/c mice.

Experimental Parasitology — Thu, 21 Jan 2010 00:00:00 +0100

Authors: Zhang H, Nishikawa Y, Yamagishi J, Zhou J, Ikehara Y, Kojima N, Yokoyama N, Xuan X Liposomes coated with neoglycolipids constructed with mannopentaose and dipalmitoylphosphatidylethanolamine (Man3-DPPE), referred to as M3-DPPE liposomes, have been shown to induce cellular immunity against antigens encapsulated therein. To evaluate whether these M3-DPPE liposomes have an adjuvant capacity against Neospora caninum infection, a novel immunization method utilizing soluble N. caninum apical membrane antigen 1 (NcAMA1) encapsulated in the M3-DPPE liposomes (M3-NcAMA1) was employed. The results revealed that a significant amount of interferon (IFN)-gamma production was detected in culture supernatants of NcAMA1 protein- or N. caninum lysate-stimulated spleen cells obtained from the m...

Developing an in-vitro method for Eimeriatenella attachment to its preferred and non-preferred intestinal sites.

Experimental Parasitology — Thu, 21 Jan 2010 00:00:00 +0100

Authors: Khazandi M, Tivey D A frozen section method utilising chicken intestinal tissue was developed to study the Eimeria tenella attachment ex vivo. In order to examine Eimeria-epithelial cell attachment, 10(5)Eimeria tenella sporozoites were incubated with each caecal frozen section (6, 10 and 14 mum) for 1 hour in 5% CO(2) incubator at 41 degrees C. Eimeria tenella sporozoites attached successfully to enterocytes in 14 mum thick of caecal sections. Sporozoite attachment to caecal sections was shown to be dependent on the number of parasites added. To evaluate the method, Eimeria tenella sporozoites were incubated to its preferred (caecum) and non-preferred (duodenum and jejunum) intestinal sites. The number of sporozoites attached to the caecal enterocytes was significantly greate...

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Developmental regulation of protein kinase A expression and activity in Schistosoma mansoni.

International Journal for Parasitology — Thu, 21 Jan 2010 00:00:00 +0100

Authors: Swierczewski BE, Davies SJ c-AMP-dependent protein kinases (PKAs) are the main transducers of cAMP signaling in eukaryotic cells. Recently we reported the identification and characterization of a PKA catalytic subunit (SmPKA-C) in Schistosoma mansoni that is required for adult schistosome viability in vitro. To gain further insights into the role of SmPKA-C in biological processes during the schistosome life cycle, we undertook a quantitative analysis of SmPKA-C mRNA expression in different life cycle stages. Our data shows that SmPKA-C mRNA expression is developmentally regulated, with the highest levels of expression in cercariae and adult female worms. To evaluate the biological role of SmPKA-C in these developmental stages, cercariae and adult worms were treated with vario...

Analysis of molecular diversity of the Trypanosoma cruzi trypomastigote small surface antigen reveals novel epitopes, evidence of positive selection and potential implications for lineage-specific serology.

International Journal for Parasitology — Thu, 21 Jan 2010 00:00:00 +0100

Authors: Bhattacharyya T, Brooks J, Yeo M, Carrasco HJ, Lewis MD, Llewellyn MS, Miles MA Chagas disease, marked by life-long chronic infection with Trypanosoma cruzi, remains a major parasitic disease in Latin America. Genetically heterogeneous, T. cruzi is divided into six discrete typing units (DTUs), most recently grouped as TcI-VI. The trypomastigote small surface antigen (TSSA) of T. cruzi has been described as the only known serological marker to identify infection by TcII-VI, as distinct from TcI. Here, by comparative analysis of a cohort of 25 reference strains representing all the known DTUs, we show that TSSA intra-specific diversity is greater than previously reported. Furthermore, TcIII and IV TSSA PCR products are, contrary to expectation, both digested by PvuII, revealing...

The Multilateral Initiative on Malaria: looking back and looking ahead.

Trends in Parasitology — Thu, 21 Jan 2010 00:00:00 +0100

Authors: Miller LH The Multilateral Initiative on Malaria (MIM) started in 1997 with the aim of giving African scientists an equal voice with Northern scientists in making decisions about malaria research in Africa. Is there a need for MIM today with the large increase in funding for malaria research from governments and foundations? I conclude that MIM is still needed today to support African scientists' investigator-initiated research and training. PMID: 20097134 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

Trypanosoma evansi: Pharmacological Evidence of a Nicotinic Acetylcholine Receptor.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Portillo R, Bruges G, Delgado D, Betancourt M, Mijares A The role of calcium and its relevance have been deeply revised with respect to trypanosomatids, as the mechanism by which calcium enters trypanosomes was, until now, not well understood. There is evidence supporting the presence of a nAChR in another member of the trypanosomatidae family, Trypanosoma. cruzi, these receptors being one entry path to calcium ions. The aims of this work were to determine if there was a nicotinic acetylcholine receptor (nAChR) in Trypanosoma evansi, and to subsequently perform a partial pharmacological characterization of this receptor. After being loaded with FURA-2 AM, individual cells of Trypanosoma evansi, were exposed to cholinergic compounds, and the cells displayed a dose-dependent res...

Single chain variable fragment antibodies selected by phage display against the sporozoite surface antigen s16 of cryptosporidium parvum.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Boulter-Bitzer JI, Lee H, Trevors JT Two human single chain variable fragment (scFv) libraries were used to select clones that bound to the surface glycoprotein S16 of Cryptosporidium parvum. Panning of the Tomlinson libraries I and J resulted in the isolation of nine distinct clones. Of the four clones which had full-length scFv, three contained stop codons. The remaining five clones were truncated, with four missing the heavy chain, and one missing most of the light chain. The full-length clones exhibited better binding to native C. parvum proteins and recombinant S16 than the truncated clones, with the exception of one truncated clone. None of the selected clones cross-reacted with Giardia lamblia, Escherichia coli, Streptococcus pyogenes, Listeria monocytogenes, Bacillus c...

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Modulation of cerebral malaria by fasudil and other immune-modifying compounds.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

We examined a number of compounds with known effects on the immune system, in a murine model of cerebral malaria. Of the compounds tested, only fasudil and curcumin had significant effects on the progression of the disease. Although neither drug caused a reduction in parasitemia, survival of the treated mice was significantly increased, and the development of cerebral malaria was either delayed or prevented. Our results support the hypothesis that an immunomodulator efficient in preventing CM should be administered together with anti-plasmodial drugs to prevent severe malaria disease; curcumin and fasudil should be further investigated to determine efficiency and feasibility of treatment. PMID: 20093114 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Molecular cloning and characterization of two genes encoding 2-Cys peroxiredoxins from Fasciola gigantica.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Chaithirayanon K, Sobhon P In Fasciola species, peroxiredoxin (Prx) serves as the major antioxidant enzyme to remove hydrogen peroxide that is generated from various metabolic reactions, because the parasites lack catalase, and only express glutathione peroxidases at minimal levels. We have cloned and characterized two genes, FgPrx-1 and FgPrx-2, belonging to the 2-Cys Prx family, by immunoscreening of an expressed adult-stage Fasciola gigantica cDNA library using a rabbit antiserum against its tegumental antigens. Predicted FgPrx-1 and FgPrx-2 consisted of 218 amino acids each with predicted molecular weights at 24.63 kDa and 24.57 kDa, respectively. The two predicted F. gigantica Prx proteins exhibited 98% identity to each other, and 52% identity to Prx from oxen which is th...

Wuchereria bancrofti: Diminished Platelet Activation in Filarial Patients.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Krushna NS, Shiny C, Verma P, Nithya D, Basker P, Elango S, Babu S, Narayanan RB Blood platelets are the innate immune elements that have not been investigated in human filarial infections. Platelet activation status in the Endemic normals (EN), microfilaria positive individuals (MF) and patients with chronic pathology (CP) was evaluated in whole blood, under unstimulated as well as antigen exposed (BmA, E.coli) conditions for PAC-1 expression by Flow cytometry. A diminished PAC-1 expression was observed in MF compared to CP and EN spontaneously as well as upon antigen exposure. Besides this, PAC-1 expression within the groups didn't exhibit any significant difference under all the experimental conditions. However in CP patients, E.coli antigen exposure resulted in a significa...

Adenine metabolism in Plasmodium falciparum.

Experimental Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Mehrotra S, Bopanna MP, Bulusu V, Balaram H Plasmodium falciparum lacks the de novo purine biosynthesis pathway and relies entirely on the salvage pathway to meet its purine nucleotide requirements. The entire flux for purine nucleotide biosynthesis in the parasite is believed to be through hypoxanthine guanine phosphoribosyltransferase (HGPRT), with the enzymes, adenosine kinase and adenine phosphoribosyltransferase (APRT) being unannotated in the Plasmodium genome database. This manuscript reports on the studies carried out to explore bypass mechanisms, if any, for AMP synthesis in the intraerythrocyitc stages of the parasite life cycle. Uptake and subsequent incorporation of radiolabel adenine in the nucleotide pool of saponin released erythrocyte free parasites implicated ...

PlasmoPredict: a gene function prediction website for Plasmodium falciparum.

Trends in Parasitology — Mon, 18 Jan 2010 00:00:00 +0100

Authors: Tedder PM, Bradford JR, McConkey GA, Bulpitt AJ, Westhead DR The genome sequence of the malaria parasite Plasmodium falciparum was published in 2002 and revealed that approximately 60% of its genes could not be assigned a function. Eight years later the majority of P. falciparum proteins are still of unknown function. We therefore present PlasmoPredict, an easy-to-use online gene function prediction tool that integrates a wide range of functional genomics data for P. falciparum to aid in the annotation of these genes. PMID: 20089451 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

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Acetate formation in the energy metabolism of parasitic helminths and protists.

International Journal for Parasitology — Sat, 16 Jan 2010 00:00:00 +0100

Authors: Tielens AG, van Grinsven KW, Henze K, van Hellemond JJ, Martin W Formation and excretion of acetate as a metabolic end product of energy metabolism occurs in many protist and helminth parasites, such as the parasitic helminths Fasciola hepatica, Haemonchus contortus and Ascaris suum, and the protist parasites, Giardia lamblia, Entamoeba histolytica, Trichomonas vaginalis as well as Trypanosoma and Leishmania spp. In all of these parasites acetate is a main end product of their energy metabolism, whereas acetate formation does not occur in their mammalian hosts. Acetate production might therefore harbour novel targets for the development of new anti-parasitic drugs. In parasites, acetate is produced from acetyl-CoA by two different reactions, both involving substrate level phos...

How do nematodes transfer phosphorylcholine to carbohydrates?

Trends in Parasitology — Sat, 16 Jan 2010 00:00:00 +0100

This article considers the nature of the biosynthetic pathway of nematode PC-containing glycoconjugates and, in particular, the identity of the final component in the pathway - the enzyme that transfers PC to carbohydrate (the 'PC transferase'). We offer the opinion that the PC transferase could be a member of the fukutin family (fukutin refers to the mutated gene product that causes Fukuyama congenital muscular dystrophy), a group of enzymes with apparent phosphoryl-ligand transferase activity that are found in organisms ranging from bacteria to humans. PMID: 20083435 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

The perils of PCR: can we accurately 'correct' antimalarial trials?

Trends in Parasitology — Sat, 16 Jan 2010 00:00:00 +0100

This article considers these limitations and proposes a framework for reporting, interpreting and improving PCR correction of antimalarial trials. PMID: 20083436 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

Schistosome genomes: a wealth of information.

Trends in Parasitology — Sat, 16 Jan 2010 00:00:00 +0100

Authors: Webster JP, Oliviera G, Rollinson D, Gower CM The blood flukes Schistosoma japonicum and Schistosoma mansoni are the first major human platyhelminth pathogens to have their genome sequences published. The work of two large international consortia offers draft sequence information and detailed analyses presenting a wealth of information addressing, in particular, metabolic and signalling pathways, host-parasite interactions and potential new drug targets. We comment on these breakthroughs and their potential applications in the study and control of schistosomes. PMID: 20083437 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

Immunodiagnosis of Taenia solium taeniosis/cysticercosis.

Trends in Parasitology — Sat, 16 Jan 2010 00:00:00 +0100

Authors: Deckers N, Dorny P Neurocysticercosis, the infection of the central nervous system by larvae of Taenia solium, is a major cause of epilepsy in developing countries. This cestode is a public health problem in most developing countries where pigs are raised and its occurrence is strongly associated with poverty. The development of immunodiagnostic tools has contributed to our knowledge on the importance of this parasite by enabling seroepidemiological surveys and community-based studies to be conducted. Here, we present a comprehensive overview of the various proteins used in antibody detection techniques, as well as the latest developments in antigen detection techniques and serodiagnosis of taeniosis. A critical view on the use of serology in epidemiological studies and clinic...

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Time series analysis of the transcriptional responses of Biomphalaria glabrata throughout the course of intramolluscan development of Schistosoma mansoni and Echinostoma paraensei.

International Journal for Parasitology — Fri, 15 Jan 2010 00:00:00 +0100

Authors: Hanington PC, Lun CM, Adema CM, Loker ES Successful colonization of a compatible snail host by a digenetic trematode miracidium initiates a complex, proliferative development program requiring weeks to reach culmination in the form of production of cercariae which, once started, may persist for the remainder of the life span of the infected snail. How are such proliferative and invasive parasites able to circumvent host defenses and establish chronic infections? Using a microarray designed to monitor the internal defense and stress-related responses of the freshwater snail Biomphalaria glabrata, we have undertaken a time course study to monitor snail responses following exposure to two different trematode species to which the snail is susceptible: the medically important Schis...

Members of the Entamoeba histolytica transmembrane kinase family play non-redundant roles in growth and phagocytosis.

International Journal for Parasitology — Fri, 15 Jan 2010 00:00:00 +0100

Authors: Buss SN, Hamano S, Vidrich A, Evans C, Zhang Y, Crasta OR, Sobral BW, Gilchrist CA, Petri WA Entamoeba histolytica contains a large and novel family of transmembrane kinases (TMKs). The expression patterns of the E. histolytica TMKs in individual trophozoites and the roles of the TMKs for sensing and responding to extracellular cues were incompletely characterized. Here we provide evidence that single cells express multiple TMKs and that TMK39 and TMK54 likely serve non-redundant cellular functions. Laser-capture microdissection was used in conjunction with microarray analysis to demonstrate that single trophozoites express more than one TMK gene. Anti-peptide antibodies were raised against unique regions in the extracellular domains of TMK39, TMK54 and PaTMK, and TMK expressi...

Effect of amphotericin B on the infection success of Schistosoma mansoni in Biomphalaria glabrata.

Experimental Parasitology — Sat, 09 Jan 2010 00:00:00 +0100

Authors: Moné Y, Mitta G, Duval D, Gourbal BE In the present study, we examined the effect of amphotericin B on larval stages (miracidia and primary sporocyst) of the helminth Schistosoma mansoni, the causative agent of human schistosomiasis. Amphotericin B (AmB) is a polyene macrolide that disturbs the function of the cell membrane; it is widely used as prophylactic antimycotic agent in in vitro culture. We show for the first time that S. mansoni miracidia infectivity is considerably reduced after AmB treatment. Moreover we demonstrate that AmB does not affect the development, growth, viability, and behavior of miracidia and primary sporocysts. Our data indicate that AmB effects on S. mansoni sporocyst prevalence are linked to the oxidative properties of AmB. These may alter the ...

A single fluorescence-based LAMP reaction for identifying multiple parasites in mosquitoes.

Experimental Parasitology — Fri, 08 Jan 2010 00:00:00 +0100

Authors: Aonuma H, Yoshimura A, Kobayashi T, Okado K, Badolo A, Nelson B, Kanuka H, Fukumoto S Vector-borne diseases, such as malaria and lymphatic filariasis, are co-endemic in large parts of the world. To develop a multiplex amplification method for the simultaneous detection of multiple insect-borne infectious diseases, we used LAMP with fluorescently labeled primers to identify the SPECT2 gene of Plasmodium berghei and the cytochrome oxidase subunit I gene of Dirofilaria immitis in mosquitoes. This technique could detect as few as 100 P. berghei-infected red blood cell-equivalents or one D. immitis microfilaria. Moreover, individual species of parasites in mosquitoes could be identified when a mixture of fluorescently labeled primer sets was used. These findings suggest that the mu...

The identification of inhibitors of Schistosoma mansoni miracidial transformation by incorporating a medium-throughput small-molecule screen.

Experimental Parasitology — Thu, 07 Jan 2010 00:00:00 +0100

Authors: Taft AS, Norante FA, Yoshino TP In Schistosoma mansoni, the miracidium-to-primary sporocyst transformation process is associated with many physiological, morphological, transcriptional and biochemical changes. In the present study we use a medium-throughput small molecule screen to identify chemical compounds inhibiting or delaying the in vitro transformation of miracidia to the sporocyst stage. The Sigma-Aldrich Library of Pharmacologically Active Compounds (LOPAC) contains 1,280 well-characterized chemical compounds with various modes of action including enzyme inhibitors, antibiotics, cell-cycle regulators, apoptosis inducers and GPCR ligands. We identified 47 compounds that greatly reduce or delay this transformation process during a primary screen of live miracidia. The m...

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Spatial and temporal factors affecting parasite genotypes encountered by hosts: Empirical data from American dog ticks (Dermacentor variabilis) parasitizing raccoons (Procyonlotor).

International Journal for Parasitology — Wed, 06 Jan 2010 00:00:00 +0100

In this study we analyzed population genetic patterns in D. variabilis at scales of the host individual (infrapopulation) and population (component population) to elucidate fine-scale spatial and temporal factors influencing transmission dynamics. We genotyped D. variabilis collected from raccoons (Procyon lotor) trapped in two habitat patches (located in Indiana, USA) which were spatially proximate (5.9 km) and limited in size (10.48 Ha and 25.47 Ha, respectively). Despite the fine spatial sampling scale, our analyses revealed significant genetic differentiation among component populations and infrapopulations (within each component population), indicating a non-random pattern of encountering tick genotypes by raccoons at both scales evaluated. We found evidence for male-biased dispersal ...

Neospora caninum excreted/secreted antigens trigger CC-chemokine receptor 5-dependent cell migration.

International Journal for Parasitology — Wed, 06 Jan 2010 00:00:00 +0100

Authors: Mineo TW, Oliveira CJ, Silva DA, Oliveira LL, Abatepaulo AR, Ribeiro DP, Ferreira BR, Mineo JR, Silva JS Neospora caninum, the causative agent of neosporosis, is an obligate intracellular parasite considered to be a major cause of abortion in cattle throughout the world. Most studies concerning N.caninum have focused on life cycle, seroepidemiology, pathology and vaccination, while data on host-parasite interaction, such as host cell migration, mechanisms of evasion and dissemination of this parasite during the early phase of infection are still poorly understood. Here we show the ability of excreted/secreted antigens from N.caninum (NcESAs) to attract monocytic cells to the site of primary infection in both in vitro and in vivo assays. Molecules from the family of cyclophilin...

Evolutionary forces on Anopheles: what makes a malaria vector?

Trends in Parasitology — Tue, 05 Jan 2010 00:00:00 +0100

Authors: Cohuet A, Harris C, Robert V, Fontenille D In human malaria, transmission intensity is highly dependent on the vectorial capacity and competence of local mosquitoes. Most mosquitoes are dead ends for the parasite, and only limited ranges of Anopheles are able to transmit Plasmodium to humans. Research to understand the determinants of vectorial capacity and competence has greatly progressed in recent years; however, some aspects have been overlooked and the evolutionary pressures that affect them often neglected. Here, we review key factors of vectorial capacity and competence in Anopheles, with a particular focus on the most important malaria vector Anopheles gambiae. We aim to point out selection pressures exerted by Plasmodium on Anopheles to improve its own transmission an...

Giardiasis - why do the symptoms sometimes never stop?

Trends in Parasitology — Tue, 05 Jan 2010 00:00:00 +0100

Authors: Robertson LJ, Hanevik K, Escobedo AA, Mørch K, Langeland N Although giardiasis is considered by most medical practitioners to be an easily treated infection, prolonged symptoms due to, or following, Giardia duodenalis infection can have a significant impact on quality of life. Symptom recurrence, including abdominal symptoms and fatigue, can result from re-infection, treatment failure, disturbances in the gut mucosa or post-infection syndromes. In developed countries, these sequelae can have an enormous impact on quality of life; in developing countries, particularly in children, they add yet another burden to populations that are already disadvantaged. Here, we outline current knowledge, based on individual case sequelae from sporadic infections, observations of populati...

Anticancer agents against malaria: time to revisit?

Trends in Parasitology — Tue, 05 Jan 2010 00:00:00 +0100

Authors: Nzila A, Okombo J, Becker RP, Chilengi R, Lang T, Niehues T The emergence of artemisinin resistance could adversely impact the current strategy for malaria treatment; thus, new drugs are urgently needed. A possible approach to developing new antimalarials is to find new uses for old drugs. Some anticancer agents such as methotrexate and trimetrexate are active against malaria. However, they are commonly perceived to be toxic and thus not suitable for malaria treatment. In this opinion article, we examine how the toxicity of anticancer agents is just a matter of dose or 'only dose makes the poison', as coined in Paracelsus' law. Thus, the opportunity exists to discover new antimalarials using the anticancer pharmacopoeia. PMID: 20056487 [PubMed - as supplied by publisher] (...

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Amoebae and algae can prolong the survival of Campylobacter species in co-culture.

Experimental Parasitology — Mon, 04 Jan 2010 00:00:00 +0100

In this study we evaluated eight different unicellular eukaryotic organisms, for their potential to serve as environmental hosts for Campylobacter species. These organisms include four amoebozoas (Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba rhysodes and Hartmanella vermiformis), one alveolate (Tetrahymena pyriformis), one stramenopile (Dinobryon sertularia), one eugoenozoa (Euglena gracilis) and one heterolobosea (Naegleria americana). Campylobacter spp. including C. jejuni, C. coli and C. lari are the most common cause of gastroenteritis in the western world. Survival and replication of these three species as well as C. hyointestinalis were assessed in co-cultures with the eukaryotic organisms. Campylobacter spp. generally survived longer in co-cultures, compared to whe...

Paragonimus westermani: Identification and characterization of the fasciclin I domain-containing protein.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

In this study, we isolated a cDNA encoding a P. westermani fasciclin I domain-containing protein (Pwfas-I). The fasiclin-I domain is suggested to be involved in cell adhesion, migration and differentiation. Immunohistochemical analysis of P. westermani adult worms with polyclonal anti-Pwfas-I serum revealed immunoreactivity in the egg shells and the cells lining the subtegumental layer of adult worm throughout the contact regions of the cyst wall and paired worms. Using cell adhesion and spreading assays, we showed that Pwfas-I supports cell adhesion and spreading. Furthermore, we determined that the alphanubeta5 integrin was a functional receptor for the Pwfas-I. Taken together, these results suggest that Pwfas-I may be functional for the modulation of cell adhesion via binding with alpha...

Entamoeba invadens, encystation process and enolase.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Segovia-Gamboa NC, Chávez-Munguía B, Medina-Flores Y, Cázares-Raga FE, Hernández-Ramírez VI, Martínez-Palomo A, Talamás-Rohana P The reptilian parasite Entamoeba invadens is accepted as a model for the study of the Entamoeba encystation process. Here we describe the production and characterization of a mAb (B4F2), generated against a component of the E. invadens cyst wall. This mAb specifically recognizes a 48 kDa protein present in cytoplasmic vesicles of cells encysting for 24 h. In mature cysts (96 h), the antigen was detected on the cyst surface. By two-dimensional electrophoresis and mass spectrometry analysis, the B4F2 specific antigen was identified as enolase. Levels of enolase mRNA were increased in encysting cells and the B4F2 mAb w...

Rhipicephalus (Boophilus) microplus: Clotting time in tick-infested skin varies according to local inflammation and gene expression patterns in tick salivary glands.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Carvalho WA, Maruyama SR, Franzin AM, Abatepaulo AR, Anderson JM, Ferreira BR, Ribeiro JM, Moré DD, Maia AA, Valenzuela JG, Garcia GR, de Miranda Santos IK Ticks deposit saliva at the site of their attachment to a host in order to inhibit haemostasis, inflammation and innate and adaptive immune responses. The anti-haemostatic properties of tick saliva have been described by many studies, but few show that tick infestations or its anti-haemostatic components exert systemic effects invivo. In the present study we extended these observations and show that, compared with normal skin, bovine hosts that are genetically susceptible to tick infestations present an increase in the clotting time of blood collected from the immediate vicinity of haemorrhagic feeding pools in skin in...

The Effect of Levamisole and Levamisole+Vitamin C on Oxidative Damage in Rats Naturally Infected with Syphacia muris.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

This study was performed to determine the effects of levamisole and levamisole + vitamin C against Syphacia muris naturally infection in rats and to detect its effect on the oxidative parameters in blood and tissues of host. For this purpose, natural infection was diagnosed using the cellophane tape method on the perianal region of rats. Infected rats (total 18) were divided into three groups. On the other hand 6 without helminth rats were used in this study as negative control group. Group 2 was given an orally levamisole HCl treatment with gastric gavage at a dose level of 20mg/kg body weight in distilled water, every alternate day. Group 3 was given levamisole HCl via gastric gavage at a dose level of 20 mg/kg and vitamin C was given 1g/L added to the drinking water. All the treatments ...

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Acanthamoebacastellanii Neff: In vitro activity against the trophozoite stage of a natural sesquiterpene and a synthetic cobalt(II)-lapachol complex.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

In this study, the in vitro activities of a natural sesquiterpene, alpha-cyperotundone, isolated from the root bark of Maytenusretusa and a cobalt(II)-complex of a natural occurring prenyl hydroxynaphthoquinone (lapachol) were evaluated against the trophozoite stage of Acanthamoeba castellanii Neff using a previously developed colorimetric 96-well microtiter plate assay, based on the oxido-reduction of Alamar Blue((R)). The obtained activities showed that these two compounds were able to inhibit the in vitro growth of the amoebae at relatively low concentrations. Further identification of the molecular targets of these products and their effects on acanthamoebae should be determined to evaluate their possible therapeutic use. PMID: 20045692 [PubMed - as supplied by publisher] (Source: ...

Entamoeba histolytica: Identification and partial characterization of alpha-mannosidase activity.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Santacruz-Tinoco CE, Villagómez-Castro JC, López-Romero E Despite their well recognized importance in pathogenesis of Entamoeba histolytica there are few studies dealing with the assembly and secretion of glycoproteins that participate in the adhesion to target cells and in the dissemination of the parasite in infected tissues. Some of these studies refer to the identification and, in some cases, the characterization of glycosyl transferases and glycosidases involved in the biosynthesis of these macromolecules as well as to compartments involved in the amoeba dolichol-linked glycosylation pathway. While an N-glycan trimming alpha-mannosidase has been demonstrated in E. histolytica, little is known on its cellular distribution and properties. Here we describe the pres...

Leishmania amazonensis: Heme stimulates (Na(+)+K(+))ATPase activity via phosphatidylinositol-specific phospholipase C /Protein Kinase C-like (PI-PLC/PKC) signaling pathways.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Almeida-Amaral EE, Cardoso VC, Francioli FG, Meyer-Fernandes JR In the present paper we studied the involvement of the phosphatidylinositol-specific PLC (PI-PLC)/protein kinase C (PKC) pathway in (Na(+)+K(+))ATPase stimulation by heme in L. amazonensis promastigotes. Heme stimulated the PKC-like activity with a concentration of 50 nM. Interestingly, the maximal stimulation of the PKC-like activity promoted by phorbol ester was of the same magnitude promoted by heme. However, the stimulatory effect of heme is completely abolished by ET-18-OCH(3) and U73122, specific inhibitors of PI-PLC. (Na(+)+K(+))ATPase activity is increased in the presence of increased concentrations of heme, being maximally affected at 50 nM. This effect was completely reversed by 10 nM calphostin C, an in...

Schistosoma mansoni: Egg-Induced downregulation of hepatic stellate cell activation and fibrogenesis.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Anthony B, Mathieson W, de Castro-Borges W, Allen J Eggs of Schistosoma mansoni trapped in human liver can lead to fibrosis. Since liver fibrosis requires activation of hepatic stellate cells (HSC) from a quiescent to a myofibroblastic phenotype, we investigated the effects of S.mansoni eggs on this process using in vitro co-cultures with human HSC and evaluated established biomarkers for activation and fibrosis. HSC demonstrate significantly reduced expression of alpha-smooth muscle actin (p<0.001), connective tissue growth factor (p<0.01) and type I collagen (p<0.001) but significantly increased expression of peroxisome proliferator-activated receptor gamma (p<0.01). Morphologically, HSC exhibited elongated fine cellular processes and reduced size, increased accu...

Toxoplasma gondii: Fluconazole and itraconazole activity against toxoplasmosis in a murine model.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

In this study, we investigated the activity of the antifungals fluconazole (FLZ) and itraconazole (ITZ) against T. gondii in mice infected with the Me49 strain. As previously reported for ITZ, FLZ also demonstrated a selective effect against T. gondiiin vitro; the IC(50) values obtained for FLZ were 8.9 muM and 3.1 muM after 24 h and 48 h of treatment, respectively. A 10-day treatment of mice with orally or intraperitoneally administered 20 mg/kg/day FLZ showed a significant survival difference compared to untreated mice. The administration of 20 mg/kg/day ITZ significantly reduced the brain cyst burden compared to untreated mice but did not exert significant protection against death. The results obtained in this work are rather promising as ITZ and FLZ are safe and low-cost drugs availabl...

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Trichinella spiralis: Immune response and protective immunity elicited by recombinant paramyosin formulated with different adjuvants.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Yang J, Gu Y, Yang Y, Wei J, Wang S, Cui S, Pan J, Li Q, Zhu X Our previous studies showed that immunization with recombinant paramyosin from T. spiralis (rTs-Pmy) formulated with Freund's adjuvant significantly reduced larval burden in mice after T. spiralis larval challenge. Since Freund's adjuvant is toxic and not a suitable adjuvant for clinical vaccine trials, we evaluated the ability of the adjuvants Montanide ISA206 and ISA720 to stimulate immune responses during rTs-Pmy immunization and to enhance protective immunity. The results revealed that immunization of BALB/c mice with rTs-Pmy formulated with either ISA206 or ISA720 triggered Th1 and Th2 immune responses similar to those produced by the conventional Freund's adjuvant formulation and also provided a similar level...

Paramphistomum cervi: Surface topography of the tegument of adult fluke.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Panyarachun B, Sobhon P, Tinikul Y, Chotwiwatthanakun C, Anupunpisit V, Anuracpreeda P Adult Paramphistomum cervi or rumen fluke are pear-shaped, slightly concave ventrally and convex dorsally. The worm measures about 5-13 mm in length and 2-5 mm in width across the mid section. As observed by scanning electron microscopy (SEM), the tegumental surface in all part of the body, appears highly corrugated with transverse folds alternating with grooves and is spineless. At high magnification, the surface of the fold is composed of microfolds or ridges separated by microgrooves or pits. Corrugations and invaginations of the ventral surface are also more extensive than on the dorsal surface of the body. Both anterior and posterior suckers have thick rims covered with transverse folds...

Neospora caninum: Early immune response of rat mixed glial cultures after tachyzoites infection.

Experimental Parasitology — Thu, 31 Dec 2009 00:00:00 +0100

Authors: Pinheiro AM, Costa SL, Freire SM, Ribeiro CS, Tardy M, El-Bachá RS, Costa MF Neospora caninum causes neurologic disease in dogs and abortion in cattle. Little is known about the immune response of the CNS against this protozoan. The aim of this study was to evaluate production of IL-6, IL-10, TNF-alpha, IFN-gamma, and NO in rat mixed glial cell cultures infected by Neospora caninum. IFN- gamma was not observed. The mean cytokine released after 24 and 72 h of infection were 3.8 +/- 0.6 and 3.7 +/- 0.6 pg TNF-alpha/mg protein and 2.7 0.69 and 4.1 +/- 0.64 pg IL-10/mg protein, respectively, and more than 8,0 pg IL-6/mg protein for both time points. NO levels increased 24h post-infection (2.3 +/- 0.8 pg/mg protein) until 72h (4.2 +/- 1.1 pg/mg protein) and the number of tachy...

Early removal of alternatively activated macrophages leads to Taenia crassiceps cysticercosis clearance in vivo.

International Journal for Parasitology — Tue, 29 Dec 2009 00:00:00 +0100

Authors: Reyes JL, Terrazas CA, Alonso-Trujillo J, van Rooijen N, Satoskar AR, Terrazas LI To determine the role of alternatively activated macrophages (AAMphis) in modulating the outcome of experimental cysticercosis caused by Taenia crassiceps, we investigated the effect of removal of AAMphi by injecting clodronate-loaded liposomes into susceptible BALB/c mice. Following T. crassiceps infection, mice receiving PBS-loaded liposomes developed a dominant Th2-type response associated with the presence of AAMphis together with antigen-specific hyporesponsiveness and high parasite burden. In contrast, similarly infected mice treated with clodronate-loaded liposomes mounted a mixed Th1/Th2-type response, reversed antigen-specific hyporesponsiveness and did not carry notable AAMphi populatio...

Darwinian interventions: taming pathogens through evolutionary ecology.

Trends in Parasitology — Fri, 25 Dec 2009 00:00:00 +0100

Authors: Williams PD From the seemingly inevitable emergence of antibiotic resistance following drug use to the necessity of annual influenza vaccine updates, the ability of pathogens to evolve appears to preclude the development of effective, long-term interventions for many diseases. Despite this gloomy forecast, recent research explores how various principles and concepts from evolutionary ecology might inform practical attempts to bring these disease-causing agents under greater human control. By utilizing evolutionary and ecological information at various scales, these works investigate some promising avenues of disease intervention, from trapping pathogens in evolutionary dead ends, through slowing or inhibiting the process of pathogen adaptation, to more accurate forecasting of ...

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Screening of Swiss hot spring resorts for potentially pathogenic free-living amoebae.

Experimental Parasitology — Thu, 24 Dec 2009 00:00:00 +0100

Authors: Gianinazzi C, Schild M, Zumkehr B, Wüthrich F, Nüesch I, Ryter R, Schürch N, Gottstein B, Müller N Free-living amoebae (FLA) belonging to Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, and Sappinia pedata are known to cause infections in humans and animals leading to severe brain pathologies. Worldwide, warm aquatic environments have been found to be suitable habitats for pathogenic FLA. The present study reports on screening for potentially pathogenic FLA in four hot spring resorts in Switzerland. Water samples were taken from water filtration units and from the pools, respectively. Amoebae isolated from samples taken during, or before, the filtration process were demonstrated to be morphologically and phylogenetically related to Stenoamoeb...

Plasmodium falciparum: In vitro interaction of quassin and neo-quassin with artesunate, a hemisuccinate derivative of artemisinin.

Experimental Parasitology — Thu, 24 Dec 2009 00:00:00 +0100

Authors: Mishra K, Chakraborty D, Pal A, Dey N Quassia amara L. (Family Simaroubaceae) is known to have several medicinal properties including the activity against malaria. An HPLC method was employed for purification of the biologically active quassinoids; quassin (Q) and neo-quassin (NQ), further characterized by MALDI-TOF analyses. Purified Q, NQ and the crude bark extract (S1) along with artesunate (AS) were studied for their in vitro anti-plasmodial activity. The in vivo toxicity studies at intraperitoneal doses with higher concentrations of the crude bark extract (S1) in Balb/C mice ruled out the apprehension of toxicity. Interaction studies between the test compounds among themselves (Q+NQ) and individually with artesunate (AS+Q, AS+NQ), were carried out in vitro at four ratios ...

Similarity in ectoparasite faunas of Palaearctic rodents as a function of host phylogenetic, geographic or environmental distances: Which matters the most?

International Journal for Parasitology — Thu, 24 Dec 2009 00:00:00 +0100

Authors: Krasnov BR, Mouillot D, Shenbrot GI, Khokhlova IS, Vinarski MV, Korallo-Vinarskaya NP, Poulin R Different host species harbour parasite faunas that are anywhere from very similar to very different in species composition. A priori, the similarity in the parasite faunas of any two host species should decrease with increases in either the phylogenetic distance, the distinctness of the environments occupied or the geographical distance between these hosts. We tested these predictions using extensive data on the faunas of fleas (Insecta: Siphonaptera) and gamasid mites (Acari: Parasitiformes) parasitic on rodents across the Palaearctic. For each pair of host species, we computed the similarity in parasite faunas based on both species composition as well as the phylogenetic and/or t...

Drug target identification, validation, characterisation and exploitation for treatment of Acanthamoeba (species) infections.

Experimental Parasitology — Tue, 22 Dec 2009 00:00:00 +0100

Authors: Roberts CW, Henriquez FL New more efficacious antimicrobials as required for the treatment of Acanthamoeba infections as those currently available require arduous treatment regimes, are not always effective and are poorly active against the cystic stages. Herein, we review potential drug targets including tubulin, alternative oxidase, amino acid biosynthesis and myosin. In addition, we review the literature for current missing tools and resources for the identification, validation and development of new antimicrobials for this organism. Additional targets should come to light through a concerted genome sequencing effort. PMID: 20035751 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

Acanthamoeba castellanii: Cellular changes induced by chlorination.

Experimental Parasitology — Mon, 21 Dec 2009 00:00:00 +0100

In conclusion, depending on the concentration used, chlorination leads to many cellular effects on Acanthamoeba that could well arise in cell inactivation. PMID: 20034490 [PubMed - as supplied by publisher] (Source: Experimental Parasitology)

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Trypanosoma rangeli: Differential expression of ecto-phosphatase activities in response to inorganic phosphate starvation.

Experimental Parasitology — Mon, 21 Dec 2009 00:00:00 +0100

Authors: Dick CF, Dos-Santos AL, Fonseca-de-Souza AL, Rocha-Ferreira J, Meyer-Fernandes JR In this work we showed that living cells of Trypanosoma rangeli express different ecto-phosphatase activities in response to different inorganic phosphate (Pi) concentrations in the culture medium. The ecto-phosphatase activity from T. rangeli grown at low Pi concentration was inhibited by the increase of the pH, while the ecto-phosphatase of the cells grown at high Pi concentration was not modulated by the change of the pH of the medium. Okadaic acid inhibited only the ecto-phosphatase activity from cells grown at low Pi concentration but not the ecto-phosphatase activity from cells grown at high Pi concentration. Accordingly, phosphatase activity from T. rangeli grown at low Pi concentration wa...

Brugia malayi: in vitro effects of ivermectin and moxidectin on adults and microfilariae.

Experimental Parasitology — Mon, 21 Dec 2009 00:00:00 +0100

Authors: Tompkins JB, Stitt LE, Ardelli BF The effect of ivermectin and moxidectin on the motility of Brugia malayi adults and microfilariae and on the fertility of B. malayi females was examined. Motility was reduced in adults after exposure to both drugs and worms were non-motile and dead within eight days. The motility of microfilariae was significantly reduced at all drug concentrations and ceased at concentrations of 2500 mug / mL and 5000 mug / mL. The motility of microfilariae released by females was reduced after exposure to both drugs, however ivermectin had a greater effect at concentrations between 170 and 5000 mug / mL. Both drugs reduced the number of microfilariae released by females and within four days their release was inhibited. The presence of the bacterial endosymbi...

Eimeria tenella: cloning and characterization of telomerase reverse transcriptase gene.

Experimental Parasitology — Mon, 21 Dec 2009 00:00:00 +0100

Authors: Yang G, Li J, Zhang X, Zhao Q, Gong P, Ren B, Zhang G Telomerase is essential for maintaining telomere length and chromosome stability in most eukaryotic organisms. The telomerase ribonucleoprotein complex consists of two essential components, the intrinsic telomerase RNA and the catalytic telomerase reverse transcriptase protein. Here we describe the cloning, sequencing and characterization of the telomerase reverse transcriptase catalytic subunit from the apicomplexan protozoon Eimeria tenella. The amino acid sequence predicted from it has all the signature motifs of the TERT family members. The E.tenella TERT cDNA contains an open reading frame encoding a protein with 1497 amino acids predicted size of 172 kDa and isoelectric point of 9.344. It contains the conserved revers...

A new species of cosmocercoides (nematoda: cosmocercidae) from a gymnophthalmid lizard of western brazil.

The Journal of Parasitology — Fri, 18 Dec 2009 00:00:00 +0100

A NEW SPECIES OF COSMOCERCOIDES (NEMATODA: COSMOCERCIDAE) FROM A GYMNOPHTHALMID LIZARD OF WESTERN BRAZIL. J Parasitol. 2009 Dec 18;:1 Authors: Strüssmann C, Silva R, Avila R Cosmocercoides sauria n. sp., an intestinal parasite of the gymnophthalmid lizard Iphisa elegans from western Brazil, is described. Of the 18 species previously described, C. sauria represents the 19th species, and the third to be reported in the Neotropical region. Moreover, C. sauria is the second species reported from a reptilian host, and is distinguished by a smaller number of rosette papillae (4 pairs). Additionally, the new species can be distinguished from the other Neotropical species (Cosmocercoides lilloi Ramallo, Bursey and Goldberg, 2007 and C. variabilis (Harwood, 1930)) by possessing sma...

Antibodies to toxoplasma gondii in stray and household dogs in guangzhou, china.

The Journal of Parasitology — Fri, 18 Dec 2009 00:00:00 +0100

ANTIBODIES TO TOXOPLASMA GONDII IN STRAY AND HOUSEHOLD DOGS IN GUANGZHOU, CHINA. J Parasitol. 2009 Dec 18;:1 Authors: Zhang H, Zhou DH, Yi-Zhou C, Lin RQ, Yuan ZG, Song HQ, Li SJ, Zhu XQ The frequency of Toxoplasma gondii antibodies in stray and household dogs in Guangzhou, China was examined by ELISA on serum samples from 150 dogs (36 strays and 114 households), and the overall prevalence was 21.3%. The extent of infection in stray dogs (33.3%) was significantly higher (P < 0.05) than in household dogs (17.5%). Infection in male and female dogs of both groups was not significantly different (P>/=0.05), 31.8% versus 35.7% for male and female in stray dogs, and 14.5% versus 22.2% in household dogs, respectively. The results of the present investigation indicate that the se...

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Prevalence of antibodies to trypanosoma cruzi, leishmania infantum, encephalitozoon cuniculi, sarcocystis neurona, and neospora caninum and in capybara, hydrochoerus hydrochaeris, from sao paulo state brazil.

The Journal of Parasitology — Fri, 18 Dec 2009 00:00:00 +0100

PREVALENCE OF ANTIBODIES TO TRYPANOSOMA CRUZI, LEISHMANIA INFANTUM, ENCEPHALITOZOON CUNICULI, SARCOCYSTIS NEURONA, AND NEOSPORA CANINUM AND IN CAPYBARA, HYDROCHOERUS HYDROCHAERIS, FROM SAO PAULO STATE BRAZIL. J Parasitol. 2009 Dec 18;:1 Authors: Valadas S, Gennari S, Yai L, Rosypal A, Lindsay D Little is known about the importance of capybara, Hydrochoerus hydrochaeris, as reservoirs for parasites of zoonotic or veterinary importance. Sera from 63 capybaras from 6 counties in the state of São Paulo, Brazil were examined for antibodies to Trypanosoma cruzi, Leishmania infantum, Encephalitozoon cuniculi, Sarcocystis neurona, and Neospora caninum using an indirect immunofluorescent antibody test. Five (8%) of the 63 capybaras had antibodies to T. cruzi epimastigotes. None of ...

Identification of zoonotic Giardia genotypes in fish.

International Journal for Parasitology — Thu, 17 Dec 2009 00:00:00 +0100

Authors: Yang R, Reid A, Lymbery A, Ryan U Apart from a single record in a shark, there have been no published studies conducted on Giardia genotypes in fish. The present study investigated the prevalence of Giardia in cultured fingerlings (n = 227), wild freshwater (n = 227) and wild marine/estuarine species (n = 255) of fish in Western Australia by PCR amplification at the 18S rRNA, glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and beta-giardin (bg) loci. Results revealed a low prevalence of Giardia, 3.8% (27/709), in fish hosts. The zoonotic Giardia species, Giardia duodenalis assemblages A, B as well as G. duodenalis assemblage E and Giardia microti were detected. The identification of zoonotic species of Giardia highlights the public health importance of investig...

Characterization of a diversity of tetraphyllidean and rhinebothriidean cestode larval types, with comments on host associations and life-cycles.

International Journal for Parasitology — Thu, 17 Dec 2009 00:00:00 +0100

Authors: Jensen K, Bullard SA Life-cycles of marine tapeworms of the orders Tetraphyllidea and Rhinebothriidea are poorly known primarily because their larvae typically lack species-level, taxonomically distinguishing adult characteristics and using morphology they can be identified to genus, family or order only. This large-scale study conducted in the northern Gulf of Mexico includes adult cestodes (25 species) collected from sharks and rays (Elasmobranchii, eight species) and larval cestodes (27 species) collected from teleosts (Neopterygii, 46 species), bivalves and gastropods (Mollusca, 24 species), and shrimps (Crustacea, five species), comprising a phylogenetically (75 species in three phyla, 14 orders and 46 families) and ecologically (e.g., benthic, epibenthic, pelagic, euryha...

Living in intermediate hosts: evolutionary adaptations in larval helminths.

Trends in Parasitology — Thu, 17 Dec 2009 00:00:00 +0100

Authors: Chubb JC, Ball MA, Parker GA In the complex life cycles of helminths, life in intermediate hosts poses special problems not covered by standard life history strategy theory. While under selection to reduce mortality and to increase growth, there is the additional problem of transmission between hosts. This review attempts to harmonise classical knowledge of the overall life cycle patterns with recent evolutionary theory as to how larval helminths exploit intermediate host tissues and avoid the gut to maximise fitness in terms of growth and mortality. It also considers the evolutionary rules by which trophically transmitted larvae are expected to increase their transmission rates to the next host. PMID: 20022560 [PubMed - as supplied by publisher] (Source: Trends in Parasit...

Giardia Sex? Yes, but how and how much?

Trends in Parasitology — Thu, 17 Dec 2009 00:00:00 +0100

Authors: Birky CW Although Giardia is of practical importance as a pathogen and has theoretical importance in evolutionary biology, it is not known whether it ever reproduces sexually. Several recent papers have shed light on this problem, without completely solving it. One paper shows that nuclei in the encysted organism can temporarily fuse and exchange genes; this may explain the genetic similarity of the two nuclei in a cell. Another paper demonstrates that Giardia does undergo sexual reproduction with outcrossing. However, we still do not know whether this involves a meiotic or a parasexual cycle, when it occurs, or how common it is. PMID: 20022561 [PubMed - as supplied by publisher] (Source: Trends in Parasitology)

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Bursts of transposition from non-long terminal repeat retrotransposon families of the RTE clade in Schistosoma mansoni.

International Journal for Parasitology — Mon, 14 Dec 2009 00:00:00 +0100

Authors: Venancio TM, Wilson RA, Verjovski-Almeida S, Demarco R The genus Schistosoma is composed of blood flukes that infect vertebrates, from which three species are major causative agents of human schistosomiasis, a tropical disease that affects more than 200 million people. Current models of the recent evolution of Schistosoma indicate multiple events of migration and speciation from an Asian ancestral species. Transposable elements are important drivers of genome evolution and have been hypothesized to have an important role in speciation. In this work, we describe a comprehensive inventory of Schistosoma mansoni and Schistosoma japonicum retrotransposons, based on their recently published genomic data. We find a considerable difference in retrotransposon representation between th...

Compounds of the upper gastrointestinal tract induce rapid and efficient excystation of Entamoeba invadens.

International Journal for Parasitology — Mon, 14 Dec 2009 00:00:00 +0100

Authors: Mitra BN, Pradel G, Frevert U, Eichinger D The infective stage of Entamoeba parasites is an encysted form. This stage can be readily generated in vitro, which has allowed identification of stimuli that trigger the differentiation of the parasite trophozoite stage into the cyst stage. Studies of the second differentiation event, emergence of the parasite from the cyst upon infection of a host, have been hampered by the lack of an efficient means to excyst the parasite and complete the life cycle in vitro. We have determined that a combination of exposures to water, bicarbonate and bile induces rapid excystment of Entamoeba invadens cysts. The high efficiency of this method has allowed the visualization of the dynamics of the process by electron and confocal microscopy, and shou...

Acanthamoeba spp. in domestic tap water in houses of contact lens wearers in the Metropolitan Area of Mexico City.

Experimental Parasitology — Sat, 05 Dec 2009 00:00:00 +0100

Authors: Bonilla-Lemus P, Ramírez-Bautista GA, Zamora-Muñoz C, Ibarra-Montes MR, Ramírez-Flores E, Hernández-Martínez MD A survey was carried out in the metropolitan area of Mexico City to determine the presence of Acanthamoeba in the tap water of houses of contact lens wearers. Water samples were taken from the mains water entry, bathroom sinks and storage containers (roof tanks, cisterns) of 27 houses; and from the solution contained in the contact lens cases. Samples were filtered and cultured onto NNE medium. The isolates were identified based on their morphological features and pathogenicity. Total and fecal coliforms, water temperature, pH, dissolved oxygen and residual free-chlorine were measured by standard methods. Forty five isolates of Acanthamoeba f...

Characterization of the protective immune response following subcutaneous vaccination of susceptible mice against Trichuris muris.

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

Authors: Dixon H, Little MC, Else KJ Trichuris muris is a laboratory model for the human whipworm Trichuris trichiura which infects approximately 1 billion people in tropical and sub-tropical countries. The development of a vaccine would control trichuriasis by promoting the acquisition of immunity during childhood, thereby reducing faecal egg output by the community into their environment. Resistance to T. muris, defined as expulsion of the parasite prior to patency, requires the development of a T helper 2 (Th2) response during a primary infection. To our knowledge this is the first study to describe the protective immune response in the peripheral lymph nodes (PLN), mesenteric lymph nodes (MLN) and colonic mucosa following s.c. vaccination against T. muris. Susceptible AKR mice were...

Investigations into human serum sensitivity expressed by stocks of Trypanosoma brucei evansi.

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

In this study, we investigated the degree of sensitivity to NHS of 15 stocks of T. b. evansi from different geographical origins and found that 10 of the stocks were completely susceptible to the action of NHS; parasites disappeared from the blood of infected mice within a few hours and the mice remained free from infection for more than 1 month. The remaining five stocks were partially resistant to NHS; although parasites initially disappeared from the circulation more than 50% of the mice showed relapse infection 10 -18 days later. Studies on one stock, T. b. evansi STIB 810, showed that the changes in parasitaemia in the infected mice were correlated with the amount of NHS inoculated (correlation factor -0.584 and P = 0.001). When this stock was passaged 25 times in mice in the presence...

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Evolution of the heme synthetic pathway in kinetoplastid flagellates: An essential pathway that is not essential after all?

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

Authors: Kořený L, Lukeš J, Oborník M For a vast majority of living organisms, heme is an essential compound that is synthesized through a conserved biosynthetic pathway. However, certain organisms are heme auxotrophs and need to obtain this molecule from exogenous sources. Kinetoplastid flagellates represent an interesting group of species, as some of them lost the complete pathway while others possess only the last three biosynthetic steps. We decided to supplement a current view on the phylogeny of these important pathogens with the expected state of heme synthesis in representative species. We propose a scenario in which the ancestor of all trypanosomatids was completely deficient of the synthesis of heme. In trypanosomatids other than members of the genus Try...

Regulated oligomerisation and molecular interactions of the early gametocyte protein, Pfg27, in Plasmodium falciparum sexual differentiation.

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

This study provides a molecular basis for Pfg27 to establish an interaction network with RNA and RNA-binding proteins and to govern its dynamic oligomerisation in developing gametocytes. PMID: 19968995 [PubMed - as supplied by publisher] (Source: International Journal for Parasitology)

Classical CD11c(+) dendritic cells, not plasmacytoid dendritic cells, induce T cell responses to Plasmodium chabaudi malaria.

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

Authors: Voisine C, Mastelic B, Sponaas AM, Langhorne J Dendritic cells play an important role in the development of immune responses in malaria, but the contribution of plasmacytoid dendritic cells (pDC) to CD4 T cell activation and immunopathology is unknown. We have investigated pDC in a Plasmodium chabaudi infection in mice. During infection, pDC increased in number and transiently up-regulated expression of Major Histocompatibility Complex class II and co-stimulatory molecules. However, in contrast to classical CD11c(high) DC, pDC could not phagocytose parasites or process parasite proteins, to activate CD4 T cells. Activation of naïve pDC, but not CD11c(high) DC, by infected red blood cells induced IFNalpha in vitro, which was dependent on the Toll-like receptor, TLR9. Howev...

Longistatin, a novel EF-hand protein from the ixodid tick Haemaphysalis longicornis, is required for acquisition of host blood-meals( *).

International Journal for Parasitology — Fri, 04 Dec 2009 00:00:00 +0100

Authors: Anisuzzaman M, Islam MK, Miyoshi T, Alim MA, Hatta T, Yamaji K, Matsumoto Y, Fujisaki K, Tsuji N Calcium and the EF-hand Ca(++)-binding proteins have been undisputedly recognized as the key players in almost all aspect of cell functions, starting from the cell's birth, during mitosis to its end with apoptosis. But in a few exceptional cases the EF-hand proteins are secreted from the cells and play their crucial roles extracellularly. Here, to our knowledge for the first time, we have identified and characterized an EF-hand Ca(++)-binding protein from the salivary glands of the ixodid tick, Haemaphysalis longicornis, herein called longistatin. Longistatin possesses two EF-hand domains which conserve canonical structure and bind with Ca(++). Both the recombinant and endogenous p...