MedWorm: Microbiology

Erratum to: “Comprehensive update of dalbavancin activity when tested against uncommonly isolated streptococci, Corynebacterium spp., Listeria monocytogenes, and Micrococcus spp. (1357 strains)”

Diagnostic Microbiology and Infectious Disease — Tue, 18 Jun 2013 09:19:20 +0100

In the article “Comprehensive update of dalbavancin activity when tested against uncommonly isolated streptococci, Corynebacterium spp., Listeria monocytogenes, and Micrococcus spp. (1357 strains)” by Ronald N. Jones and Matthew G. Stilwell in the June 2013 issue (2013;76:239-240; doi: 10.1016/j.diagmicrobio.2013.01.002), a column heading in table 1 incorrectly states “Cumulative % inhibited by daptomycin at MIC (μg/mL).” The correct heading should be “Cumulative % inhibited by dalbavancin at MIC (μg/mL).” The authors regret the errors. (Source: Diagnostic Microbiology and Infectious Disease)

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Molecular epidemiology of Escherichia coli O25b-ST131 isolates causing community-acquired UTIs in Mexico

Diagnostic Microbiology and Infectious Disease — Tue, 18 Jun 2013 09:19:19 +0100

Abstract: Escherichia coli is a common uropathogen causing community-acquired urinary tract infections (UTIs). Out of 4735 E. coli community-acquired UTIs, 10.2% were extended spectrum β-lactamases (ESBL)-producing. The identified ESBL types were CTX-M-15 (96.4%), SHV-2a (3%), and TLA-1 (1%). Of the isolates, 94.6% tested positive for plasmid-mediated quinolone resistance (PMQR) genes (aac(6′)-lb-cr [92.1%] and qepA1 [7%] and for qnr-determinants [3.5%]). E. coli O25b-ST131 was identified in 25% of the isolates that harbor a non-conjugative 160-kb plasmid (IncFIA) containing the CTX-M-15, and all of these isolates were found to contain PMQR genes. This work can be useful in modeling the potential impact that may have on community-acquired UTIs in Mexico. (Source: Diagnostic Microbiology...

Nephrotoxicity and other adverse events among inpatients receiving liposomal amphotericin B or amphotericin B lipid complex

Diagnostic Microbiology and Infectious Disease — Tue, 18 Jun 2013 09:19:18 +0100

This study demonstrated that L-AMB is associated with less nephrotoxicity, infusion reactions and hypomagnesemia than ABLC in patients at increased risk of nephrotoxicity. (Source: Diagnostic Microbiology and Infectious Disease)

Clostridium difficile PCR ribotype 046 common among neonatal pigs and humans in Sweden

Clinical Microbiology and Infection — Tue, 18 Jun 2013 09:17:13 +0100

Induction of caspase 3 activation by multiple L. pneumophila Dot/Icm substrates

Cellular Microbiology — Tue, 18 Jun 2013 09:16:47 +0100

Abstract The intracellular pathogen Legionella pneumophila is able to strike a balance between the death and survival of the host cell during infection. Despite the presence of high level of active caspase‐3, the executioner caspase of apoptotic cell death, infected permissive macrophages are markedly resistant to exogenous apoptotic stimuli. Several bacterial molecules capable of promoting the cell survival pathways have been identified, but proteins involved in the activation of caspase‐3 remain unknown. To study the mechanism of L. pneumophila‐mediated caspase‐3 activation, we tested all known Dot/Icm substrates for their ability to activate caspase‐3. Five effectors capable of causing caspase‐3 activation upon transient expression were identified. Among these, by using its ...

Arxula adeninivorans xanthine oxidoreductase and its application in the production of food with low purine content

Journal of Applied Microbiology — Tue, 18 Jun 2013 09:16:14 +0100

ConclusionsIt was shown that induced A. adeninivorans can produce sufficient amount of xanthine dehydrogenase and that the enzyme is able to reduce xanthine and hypoxanthine content in food and when used in conjunction with other enzymes of the pathway, uric acid concentration is significantly reduced. Significance and Impact of the StudyReduction of dietary purines is recommended to people suffering of hyperuricemia. Elimination of most purine‐rich foods may affect balanced nutrition. Food with lowered purine concentration will assist in controlling the disease. This study is a continuation of previous studies that characterised and over‐expressed other enzymes of the purine degradation pathway.This article is protected by copyright. All rights reserved. (Source: Journal of Applied Mi...

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A gene determining a new member of the SARP‐family contributes to transcription of genes for the synthesis of the angucycline polyketide auricin in Streptomyces aureofaciens CCM 3239

FEMS Microbiology Letters — Tue, 18 Jun 2013 09:15:29 +0100

New virus discovered in patients with central nervous system infections

EurekAlert! - Medicine and Health — Tue, 18 Jun 2013 04:00:00 +0100

(American Society for Microbiology) Patients in Vietnam and other locations with central nervous system infections may well be suffering from the effects of a newly discovered virus, according to a study to be published in mBio®, the online open-access journal of the American Society for Microbiology. (Source: EurekAlert! - Medicine and Health)

Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain

BMC Microbiology - Latest articles — Tue, 18 Jun 2013 04:00:00 +0100

Conclusions: The population structure of clinical P. aeruginosa present in our hospital indicates the coexistence of nonresistant and resistant isolates with the same sequence type. The multiresistant isolates studied are grouped in the prevalent sequence types found in other Spanish hospitals and at the international level, and the susceptible isolates correspond mainly to singleton sequence types. (Source: BMC Microbiology - Latest articles)

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Polymyxin P is the active principle in suppressing phytopathogenic Erwinia spp. by the biocontrol rhizobacterium Paenibacillus polymyxa M-1

BMC Microbiology - Latest articles — Tue, 18 Jun 2013 04:00:00 +0100

Conclusions: Identical morphological changes in the cell wall of the bacterial phytopathogens treated with either crude polymyxin P or culture supernatant of M-1 corroborated that polymyxin P is the main component of the biocontrol effect exerted by strain M-1 against phytopathogenic Erwinia spp. (Source: BMC Microbiology - Latest articles)

Loss of neurovirulence is associated with reduction of cerebral capillary sequestration during acute Babesia bovis infection

Parasites and Vectors — Tue, 18 Jun 2013 04:00:00 +0100

Cerebral biopsies of spleen intact calves inoculated intravenously with a parental virulent or passage-derived attenuated strain of B. bovis were evaluated for capillary sequestration. Sequestration was significantly reduced, but not eliminated, after multiple passages and attenuation. Image: Sequestration of infected erythrocytes in a cerebral capillary of a calf infected with virulent Babesia bovis. (Source: Parasites and Vectors)

New endemic foci of tick-borne encephalitis (TBE) identified in districts where testing for TBE was not available before 2009 in Poland

Parasites and Vectors — Tue, 18 Jun 2013 04:00:00 +0100

We detected new tick-borne encephalitis endemic districts by offering systematic screening of all suspect TBE cases in 105 hospitals located in 11/16 Polish hospitals. Image: TBE endemic districts in northern Poland. (Source: Parasites and Vectors)

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Abundance of water bodies is critical to guide mosquito larval control interventions and predict risk of mosquito-borne diseases

Parasites and Vectors — Tue, 18 Jun 2013 04:00:00 +0100

Spatial distribution of water bodies sampled in the field (blue points) overlaid on land use (green, red, grey, and blue are forest, re-growth vegetation, deforested/grass/crops, and water, respectively) in the Peruvian Amazon. Image: Land use map and water bodies sampled in the field (blue points). (Source: Parasites and Vectors)

Investigation into an unusual increase of human cases of Salmonella Goldcoast infection in Hungary in 2009.

Euro Surveill — Mon, 17 Jun 2013 15:50:02 +0100

We describe the outbreak investigation associated with an unusual increase in Salmonella Goldcoast cases in Hungary observed in autumn 2009, which included descriptive and analytical epidemiological studies and microbiological and veterinary investigations. Sixty cases were identified between 1 January 2009 and 1 March 2010, 50 of them from late July 2009 to January 2010. Of 50 S. Goldcoast isolates, 44 showed an indistinguishable pulsed-field gel electrophoresis profile. We conducted a matched case-control study that indicated a statistically significant association between S. Goldcoast infection and the consumption of pork cheese. The majority of cases (seven of nine) reporting consumption of this product belonged to a single family cluster. After removing six cases of this cluster, pork...

Why Water Quality Tests Don't Always Accurately Capture Health Risks For Swimmers

Health News from Medical News Today — Mon, 17 Jun 2013 08:00:00 +0100

A toxin dangerous to humans may help E. coli fend off aquatic predators, enabling strains of E. coli that produce the toxin to survive longer in lake water than benign counterparts, a new study finds. Researchers from the University at Buffalo and Mercyhurst University reported these results online in the journal Applied and Environmental Microbiology. "The take-home lesson is that E. coli that produce Shiga toxin persisted longer in recreational water than E. coli that don't produce this toxin," said UB Professor of Biological Sciences Gerald Koudelka, PhD, who led the study... (Source: Health News from Medical News Today)

News From Frontiers In Microbiology, Oncology, Neuroscience

Health News from Medical News Today — Mon, 17 Jun 2013 07:00:00 +0100

Frontiers in Microbiology Insights into fungal communities in composts revealed by 454-pyrosequencing: Implications for human health and safety Composting is a process for converting waste into materials beneficial for plant growth through the action of microbes, especially of fungi which can break down large molecules. But fungi involved in composting are not always harmless. Vidya De Gannes and colleagues show that composts can contain more fungi that are potentially harmful to humans than was previously realized... (Source: Health News from Medical News Today)

Antibacterial activity of extracellular compounds produced by a Pseudomonas strain against methicillin-resistant Staphylococcus aureus (MRSA) strains

Annals of Clinical Microbiology and Antimicrobials — Mon, 17 Jun 2013 04:00:00 +0100

Conclusions: These results suggest that P. aeruginosa-produced compounds such as phenazines have inhibitory effects against MRSA and may be a good alternative treatment to control infections caused by MRSA. (Source: Annals of Clinical Microbiology and Antimicrobials)

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Recombinational cloning of the antibiotic biosynthetic gene clusters in linear plasmid SCP1 of Streptomyces coelicolor A3(2)

FEMS Microbiology Letters — Mon, 17 Jun 2013 04:00:00 +0100

We report here development of a recombinational cloning method for deleting large segment from one telomere of SCP1 followed by replacing with the telomere of pSLA2 and sequentially inserting with the overlapping cosmids in vivo. The procedure depends on homologous recombination coupled with cleavage at telomere termini by telomere terminal protein. Using this procedure, we cloned the 81‐kb avermectin and the 76‐kb spinosad biosynthetic gene clusters into SCP1. Heterologous expression of avermectin production in S. coelicolor was detected. These results demonstrate the utility of SCP1 for cloning large DNA segments such as antibiotic biosynthetic gene clusters. (Source: FEMS Microbiology Letters)

Phospho‐regulation and nucleocytoplasmic trafficking of CrzA in response to calcium and alkaline‐pH stress in Aspergillus nidulans

Molecular Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Abstract Tolerance to abiotic stresses by microorganisms require of appropriate signaling and regulatory pathways. Calcineurin phosphatases mediate calcium‐dependent signaling pathways which are widely distributed among phylogeny. In Saccharomyces cerevisiae, calcineurin mediates the post‐translational modification of downstream effectors, most of them transcription factors, being the best characterized the calcineurin‐regulated zinc‐finger factor 1, Crz1p. Here we study the signaling process of CrzA, a filamentous fungal Crz orthologue, in response to calcium and ambient‐pH alkalinization. In Aspergillus nidulans resting cells CrzA locates in the cytoplasm being excluded from nuclei. CrzA is a phospho‐protein and upon calcium, manganese or alkaline‐pH stresses, accumulates i...

The insecticidal toxin genes of Yersinia enterocolitica are activated by the thermolabile LTTR‐like regulator TcaR2 at low temperatures

Molecular Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Summary Temperature‐dependent activation of bacterial virulence factors at 37°C is well investigated. The molecular mechanism underlying the expression of toxicity determinants at environmental temperatures, however, has not been characterized. The insecticidal activity of Yersinia enterocolitica strain W22703 requires the toxin complex subunit A (TcaA) encoded on the pathogenicity island Tc‐PAIYe. Genes tcaA and tcaB encoding this subunit are maximally produced at low temperatures (10‐20°C), but repressed at body temperature. Two further insecticidal genes, tcaC (subunit B) and tccC1 (subunit C), are silent at both temperatures. A novel LysR‐type transcriptional regulator (LTTR), TcaR2, revealed to be autoregulated and essential for tcaA and tcaB expression in W22703. Expression...

Nuclease A (Gbs0661), an extracellular nuclease of Streptococcus agalactiae, attacks the neutrophil extracellular traps and is needed for full virulence

Molecular Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

In this study, we observed that respiration growth of GBS led to the extracellular accumulation of a putative nuclease, identified as being encoded by the gbs0661 gene. When overproduced in Lactococcus lactis, the protein was found to be a divalent cation‐requiring, pH‐stable, and heat‐stable nuclease that we named Nuclease A (NucA). Substitution of the histidine148 by alanine reduced nuclease activity of the GBS wild type strain, indicating that NucA is the major nuclease ex vivo. We determined that GBS is able to degrade the DNA matrix comprising the neutrophil extracellular trap (NET). The nucAH148A mutant was impaired for this function, implicating NucA in the virulence of GBS. In vivo infection studies confirmed that NucA is required for full infection, as the mutant strain allo...

The C‐terminal linker of Escherichia coli FtsZ functions as an intrinsically disordered peptide

Molecular Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Summary The tubulin homologue FtsZ provides the cytoskeletal framework and constriction force for bacterial cell division. FtsZ has an ∼ 50‐amino‐acid (aa) linker between the protofilament‐forming globular domain and the C‐terminal (Ct) peptide that binds FtsA and ZipA, tethering FtsZ to the membrane. This Ct‐linker is widely divergent across bacterial species and thought to be an intrinsically disordered peptide (IDP). We confirmed that the Ct‐linkers from three bacterial species behaved as IDPs in vitro by circular dichroism and trypsin proteolysis. We made chimeras, swapping the Escherichia coli linker for Ct‐linkers from other bacteria, and even for an unrelated IDP from human α‐adducin. Most substitutions allowed for normal cell division, suggesting that sequenc...

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Characterization of Tetracycline‐resistant Bacteria in an Urbanizing Subtropical Watershed

Journal of Applied Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Bioaugmentation of chromium polluted soil microcosms with Candida tropicalis diminish phytoavailable chromium

Journal of Applied Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

ConclusionThe Cr(VI) removal activity was found in both cytoplasmic and membrane fractions. Both, live and dead biomass of C. tropicalis were capable to reduce Cr(VI) in the soil and limit the toxicity of this metal to clover seedlings. Significance and Impact of the StudyThis study is one of the few documents which present the ability of dead yeast to limit phytoavailability of Cr(VI) from soil. This is of great significance in bioremediation of Cr(VI) contaminated soil.This article is protected by copyright. All rights reserved. (Source: Journal of Applied Microbiology)

Design and Construction of a Single Tube, Quantitative End‐Point, LATE‐PCR Multiplex Assay for Ventilator‐Associated Pneumonia

Journal of Applied Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

ConclusionsThis LATE‐PCR single tube multiplex assay generated end‐point fluorescent contours that allowed identification of all microbial pathogens commonly responsible for VAP, including MRSA. The assay was quantitative, identifying the pathogens present in the sample, no matter whether there were as few a 10 or as many 100,000 target genomes. Significance and Impact of the StudyThis assay is rapid, reliable, and sensitive and is ready for preclinical testing using samples recovered from patients suffering from Ventilator‐Associated Pneumonia.This article is protected by copyright. All rights reserved. (Source: Journal of Applied Microbiology)

Optimization of submerged fermentation of Thelephora ganbajun zang

Journal of Basic Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Abstract The effects of the fermentation conditions on both the biomass yield and the organic selenium yield of Thelephora ganbajun zang were studied. The components most suitable for the submerged fermentation medium were examined using the orthogonal array method; they comprised sucrose at 30 g L−1, carbamide 1 g L−1, corn steep liquor 8 g L−1, MgSO4·7H2O 0.3 g L−1, KH2PO4 0.5 g L−1, and NaCl 5 g L−1. The optimum cultivation conditions that resulted in maximal biomass yield were obtained using the response surface methodology (RSM). The conditions were as follows: initial pH, 5.84; temperature, 26.16 °C; and rotation speed, 170 rpm. Feeding sucrose led to a higher biomass yield, with a maximum of 21.20 g L−1. The biomass yield and the organ...

Thermostable lipase from Geobacillus sp. Iso5: Bioseparation, characterization and native structural studies

Journal of Basic Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Abstract The extracellular thermoalkaline lipase from Geobacillus sp. Iso5 was purified to homogeneity by ultrafiltration, 6% cross‐linked agarose and Phenyl spehrose HIC column chromatography. The final purified lipase resulted in 8.7‐fold with 6.2% yield. The relative molecular weight of the enzyme was determined to be a monomer of 47 kDa by SDS–PAGE and MALDI‐TOF MS/MS spectroscopy. The purified enzyme exhibit optimum activity at 70 °C and pH 8.0. The enzyme retained above 90% activity at temperatures of 70 °C and about 35% activity at 85 °C for 2 h. However, the stability of the enzyme decreased at the temperature over 90 °C. The enzyme activity was promoted in the presence of Ca2+ and Mg2+ and strongly inhibited by HgCl2, PMSF, DTT, K+, Co2+, and Zn 2+. EDTA di...

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Optimization of electroporation conditions for toyocamycin producer Streptomyces diastatochromogenes 1628

Journal of Basic Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

In this study, we optimized experimental factors involved in the electroporation transformation process. Key features of this procedure, including collection of cells at the mid‐log phase stage and the treatment of cells with lysozyme and penicillin G prior to the electroporation and recovery medium and time, produced the greatest increase in the efficiency and consistency of results. The transformation efficiency also depends on field strength, cell concentration, and plasmid DNA quantity. Under the optimal conditions, a maximal efficiency of (3 ± 0.4) × 104 µg−1 DNA was obtained. The development of transformation method for S. diastatochromogenes 1628 will foster genetic manipulation of this important strain. (Source: Journal of Basic Microbiology)

Purification and characterization of the extracellular laccase produced by Trametes polyzona WR710–1 under solid‐state fermentation

Journal of Basic Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Abstract Laccase from Trametes polyzona WR710–1 was produced under solid‐state fermentation using the peel from the Tangerine orange (Citrus reticulata Blanco) as substrate, and purified to homogeneity. This laccase was found to be a monomeric protein with a molecular mass of about 71 kDa estimated by SDS–PAGE. The optimum pH was 2.0 for ABTS, 4.0 for L‐DOPA, guaiacol, and catechol, and 5.0 for 2,6‐DMP. The Km value of the enzyme for the substrate ABTS was 0.15 mM, its corresponding Vmax value was 1.84 mM min−1, and the kcat/Km value was about 3960 s−1 mM−1. The enzyme activity was stable between pH 6.0 and 8.0, at temperatures of up to 40 °C. The laccase was inhibited by more than 50% in the presence of 20 mM NaCl, by 95% at 5 mM of Fe2+, and it was comp...

Scatter: a novel family of miniature inverted‐repeat transposable elements in the fungus Botrytis cinerea

Journal of Basic Microbiology — Mon, 17 Jun 2013 04:00:00 +0100

Abstract Miniature inverted‐repeat transposable elements (MITEs) are short non‐autonomous DNA transposons that play an important role in genome structure and function. Here, we described a novel family of MITEs, named Scatter, identified from the genomes of three strains of the fungus Botrytis cinerea (T4, B05.10, and TBC‐A). Intact Scatter elements are typically an average of 247 bp, and contain 41 bp terminal inverted repeats (TIRs) and 2‐bp “TA” target site duplications (TSDs). Based a search against the transposable elements database and GenBank, Scatter is a novel and potentially species‐specific family of MITEs. Moderate heterogeneity in sequence and size of individual Scatter copies suggests that Scatter elements were not recently proliferated. Most integrated site...

Community acquisition of beta-lactamase producing Enterobacteriaceae in neonatal gut

BMC Microbiology - Latest articles — Mon, 17 Jun 2013 04:00:00 +0100

Conclusions: Data strongly suggests that in absence of any antibiotic pressure there is tremendous load of antibiotic resistance to beta-lactam drugs. Wide spread presence of ESBL and AmpC can drive rapid emergence and dissemination of CRE. This is the first report from India which depicts the smaller picture of true antibiotic pressure present in the Indian community. (Source: BMC Microbiology - Latest articles)

Metaproteomic analysis of ratoon sugarcane rhizospheric soil

BMC Microbiology - Latest articles — Mon, 17 Jun 2013 04:00:00 +0100

Conclusions: Our experiments revealed that sugarcane ratooning practice induced significant changes in the soil enzyme activities, the catabolic diversity of microbial community, and the expression level of soil proteins. They influenced the biochemical processes in the rhizosphere ecosystem and mediated the interactions between plants and soil microbes. (Source: BMC Microbiology - Latest articles)

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Prevalence of antibodies to Leishmania infantum and Toxoplasma gondii in horses from the north of Portugal

Parasites and Vectors — Mon, 17 Jun 2013 04:00:00 +0100

Seroprevalences of Leishmania infantum (4.0%) and Toxoplasma gondii (13.3%) were estimated in 173 horses from the north of Portugal. Horses are exposed to and may be infected with these zoonotic protozoa in this geographical region. Image: Carrico and Rebelde, crossbred horses from northern Portugal. (Source: Parasites and Vectors)

Pathogenic analysis of Borrelia garinii strain SZ isolated from northeastern China

Parasites and Vectors — Mon, 17 Jun 2013 04:00:00 +0100

Our objectives investigated the pathogenicity of B. garinii SZ in a BALB/C mice model. The results indicated the difference in the clinical manifestation was highly correlated with the difference of the spirochete burden. The B. garinii SZ strain is highly pathogenic and can trigger multi-system pathological damage in mice. Image: Dermacentor ticks, from which we isolated B. garinii SZ strain. (Source: Parasites and Vectors)

Foreword

Current Problems in Surgery — Sun, 16 Jun 2013 23:18:18 +0100

Clostridium difficile was first reported as the cause of antibiotic-associated colitis in 1978. Over the subsequent 3 decades, we have witnessed a dramatic increase in the incidence and severity of infections with this organism. Today, not only do surgeons encounter pseudomembranous colitis in their own postoperative patients but they are frequently called upon to intervene in patients with the most severe disease. In this issue of Current Problems in Surgery, Drs J. Daniel Stanley, John Bartlett, Benjamin Dart, and John Ashcraft have written a masterful overview on this topic entitled, “Clostridium difficile Infection.” They begin with a discussion of the history of this often hospital-acquired infection, including its association with clindamycin therapy and the development of more v...

Stuart Chant obituary

Guardian Unlimited Science — Sun, 16 Jun 2013 13:57:28 +0100

My father, Stuart Chant, who has died aged 83, was a microbiologist by profession, but had numerous personal interests – history, music, theatre, sport (particularly as a tennis player, and supporter of Scotland's rugby team) – and was also a family man, teacher, good friend and neighbour. He was an active member of the United Reformed Church, New Malden, serving as deacon and subsequently elder.Stuart was born in Rutherglen, Scotland. His father died when he was 11, leaving his mother, Janet, to raise Stuart and his older brother Ian on few resources, but with much resourcefulness. Although Janet hailed from Lancashire and her relatives urged her to return there on her husband's death, she chose to stay in Edinburgh to ensure her sons' education was not interrupted.Because of the deat...

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Molecular Approach to Microbiological Examination of Water Quality in the Grand Bay National Estuarine Research Reserve (NERR) in Mississippi, USA.

Environmental Health Insights — Sun, 16 Jun 2013 12:25:01 +0100

The objective of this study was to evaluate the microbiological quality of water in the Grand Bay NERR and determine the levels and potential source(s) of human fecal pollution. To achieve this goal, water samples were collected aseptically every month in Bayou Heron, Bayou Cumbest, Point Aux Chenes Bay and Bangs Lake. Enterococci were concentrated from water samples by membrane filtration according to the methodology outlined in USEPA Method 1600. After incubation, DNA was extracted from bacteria colonies on the membrane filters by using QIAamp DNA extraction kit. Water samples were also tested for the presence of traditional indicator bacteria including: heterotrophic plate count, total coliforms, fecal coliforms, and Enterococcus bacteria. The marker esp gene was detected in one site of...

Ex vivo porcine vaginal mucosal model of infection for determining effectiveness and toxicity of antiseptics

Journal of Applied Microbiology — Sun, 16 Jun 2013 04:00:00 +0100

ConclusionsAll antiseptics tested in the mucosal MSSA infection model reduced MSSA. CHG and PI were more potent in broth culture. Significance and Impact of the StudyWe developed a semi‐high through‐put mucosal model that can identify compounds or formulations with promising antimicrobial and limited cytotoxic properties.This article is protected by copyright. All rights reserved. (Source: Journal of Applied Microbiology)

Isolation and characterization of probiotic properties of Lactobacilli isolated from rat fecal microbiota

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

The objective of the present study was to characterize lactobacilli isolates from the feces of male Wistar rats. Various physiological features of the candidate probiotic isolates were preliminarily investigated, including tolerance to simulated gastric juice and bile salts, antimicrobial activity, antibiotic susceptibility and in vitro aggregation. Based on their morphological and biochemical characteristics, four potential probiotic isolates (CS2, CS3, CS4, and CS7) were screened. The isolates showed good tolerance to stimulated gastric juice and bile salts. CS4 and CS7 exhibited strong antibacterial activities against the pathogens tested as assessed in neutral pH culture supernatants. All lactobacilli isolates were susceptible to all the tested antibiotics, except vancomycin. Moreover,...

Oral immunization of mice with Saccharomyces cerevisiae expressing a neutralizing epitope of ApxIIA exotoxin from Actinobacillus pleuropneumoniae induces systemic and mucosal immune responses

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

ABSTRACT An oral delivery system based on ApxIIA#5‐expressed on Saccharomyces cerevisiae was studied for its potential to induce immune responses in mice. Murine bone marrow‐derived dendritic cells (DCs) stimulated in vitro with ApxIIA#5‐expressed on S. cerevisiae upregulated the expression of maturation and activation markers, leading to production of tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐12p70 and IL‐10. Presentation of these activated DCs to cluster of differentiation CD4+ T cells collected from mice that had been orally immunized with the ApxIIA#5‐expressed on S. cerevisiae elicited specific T‐cell proliferation. In addition, the orally immunized mice had stronger antigen‐specific serum IgG and IgA antibody responses and larger numbers of antigen‐spec...

Herpes simplex virus type 1 virion‐derived US11 inhibits type 1 interferon‐induced protein kinase R phosphorylation

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

ABSTRACT The herpes simplex virus type 1 (HSV‐1) VRTK− strain that was previously isolated in our laboratory as an acyclovir‐resistant thymidine kinase (TK)‐deficient mutant, is more sensitive to type 1 interferon than is the parent strain VR3. The properties of this mutant were investigated to clarify the mechanism for its hyper‐sensitivity to interferon (IFN). It was found that: (i) IFN‐pretreated cells, but not those treated with IFN after adsorption, are hyper‐sensitive to IFN; (ii) the mutant cannot inhibit protein kinase R phosphorylation efficiently during the early stage of replication (2 hrs post‐infection); (iii) expression of US11 in infected cells and its incorporation into the virion is reduced in the mutant compared to the wild type, despite the fact that a ...

X4‐tropic human immunodeficiency virus IIIB utilizes CXCR4 as coreceptor, as distinct from R5X4‐tropic viruses

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

In this study, the requirement for amino terminal regions (NTRs) of CXCR4 for entry of HIV‐1IIIB virus into host cells was examined and compared to that of R5X4‐tropic viruses. CXCR4 and its deletion mutant (CXCR4ΔNTR23; first 23 amino acids removed from NTR) were amplified to examine their coreceptor activities. NP‐2/CD4/CXCR4 and NP‐2/CD4/CXCR4ΔNTR23 cell lines were prepared accordingly. Indirect immune fluorescence assay (IFA), PCR, and reverse transcriptase (RT) activity were used to compare the process of infection of host cells by HIV‐1IIIB virus, one R5‐tropic and five other R5X4‐tropic viruses. All the R5X4‐tropic HIVs were found to utilize both CCR5 and CXCR4 but unable to use CXCR4ΔNTR23 as coreceptors. In contrast, X4‐tropic HIV‐1IIIB was found to preferen...

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Lipopolysaccharide accelerates collagen‐induced arthritis in association with rapid and continuous production of inflammatory mediators and anti‐type II collagen antibody

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

In this study, type II collagen (CII)‐immunized mice were found to have marked increases in degree of expression of mRNA of inflammatory mediators such as tumor necrosis factor alpha (TNF‐α), interleukin (IL)‐1β, and macrophage inflammatory protein‐2 (MIP‐2) in their arthritic paws and of serum anti‐CII antibody concentration before the onset of arthritis induced by LPS injection. The gene expression was rapid and continuous after direct activation of nuclear factor κB. The amounts of mRNA of TNF‐α, IL‐1β, and MIP‐2, as well as of matrix metalloproteinases and the receptor activator of nuclear factor κB ligand, increased with the development of arthritis, correlated positively with clinical severity and corresponded with histopathological changes. Moreover, anti‐T...

New immunological investigations on Helicobacter pylori‐induced gastric ulcer in patients

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

ABSTRACT Although Helicobacter pylori (Hp) plays an important role in the pathogenesis of chronic gastritis and gastric ulcer, little is known about the probable mechanisms of these types of gastrointestinal damage. To determine the precise mechanisms involved in ulcer formation, immune responses in patients with gastric ulcer (GUP) caused by Hp infection (Hp+) were compared with those of other gastritis patients (GP). The sensitivity and proliferation of peripheral blood mononuclear cells (PBMNCs) obtained from patients were evaluated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay against exposure with complex Hp crude antigen (HPCA) and mitogen (phytohemagglutinin, PHA). Production of inflammatory cytokines, including interleukin (IL)‐1β and IL...

Influence of acute salinity changes on biochemical, hematological and immune characteristics of Fenneropenaeus indicus during white spot syndrome virus challenge

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

Abstract The present study reports the influence of salinity (5, 15, 25 and 35 g/L) on the biochemical and immune characteristics of Fenneropenaeus indicus challenged with 5. 5 × 104 copy number of white spot syndrome virus (WSSV). F. indicus that had been reared in 25 g/L, injected with WSSV and transferred to 5, 15, 25 (control) and 35 g/L were examined after 0–120 hrs for total hemocyte count (THC), phenoloxidase (PO) and respiratory burst (RB) activity and alkaline and acid phosphatase activities. It was concluded that F. indicus that had been transferred from 25 g/L to lower and higher salinity levels (5, 15 and 35 g/L) had poorer immune indices and decreased resistance against WSSV infection. After 120 hrs, the mortality rate in WSSV‐injected F. indicus experim...

A bio‐nanocapsule containing envelope protein domain III of Japanese encephalitis virus protects mice against lethal Japanese encephalitis virus infection

Microbiology and Immunology — Sun, 16 Jun 2013 04:00:00 +0100

Emergence of Rifampicin, Tigecycline, and Colistin-Resistant Acinetobacter baumannii in Iran; Spreading of MDR Strains of Novel International Clone Variants

Microbial Drug Resistance — Sun, 16 Jun 2013 03:03:34 +0100

Microbial Drug Resistance , Vol. 0, No. 0. (Source: Microbial Drug Resistance)

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Microbiological profile and nutritional quality of raw foods for neutropenic patients under hospital care

Revista Brasileira de Hematologia e Hemoterapia — Sat, 15 Jun 2013 23:19:23 +0100

CONCLUSION: The fresh fruits and vegetables properly sanitized in this study had a microbiological profile consistent with that required by Brazilian law. Furthermore, the nutritional value of the neutropenic diet is diminished, at least in terms of the vitamin C content. (Source: Revista Brasileira de Hematologia e Hemoterapia)

Strain-specific probiotics properties of Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus brevis isolates from Brazilian food products.

Food Microbiology — Sat, 15 Jun 2013 22:50:04 +0100

Authors: Ramos CL, Thorsen L, Schwan RF, Jespersen L Abstract A total of 234 LAB isolates from Brazilian food products were initially screened for their ability to survive at pH 2.0. Fifty one of the isolates survived and were selected. They were characterized by phenotypic methods, rep-PCR and identified using 16S rRNA gene sequencing as Lactobacillus fermentum (34 isolates), Lactobacillus plantarum (10) and Lactobacillus brevis (7). Based on being either highly tolerant to bile, showing an ability for auto-aggregation and/or hydrophobic properties, one L. fermentum (CH58), three L. plantarum (CH3, CH41 and SAU96) and two L. brevis (SAU105 and FFC199) were selected. The highest co-aggregation ability with Escherichia coli was observed to L. plantarum CH41. L. brevis SAU105 an...

Use of a bacteriophage to inactivate Escherichia coli O157:H7 on beef.

Food Microbiology — Sat, 15 Jun 2013 22:50:04 +0100

We describe the isolation and characterisation of phage FAHEc1, which infects E. coli O157, and its ability to kill its host in vitro and on beef. The phage belonged to the family Myoviridae and lysed 28 of 30 E. coli O157 (:H7, :HNM and :H not specified) isolates, only one other non-O157 E. coli serotype (O162:H7), and none of the other 13 bacterial species tested. The phage did not contain stx1, stx2, eae or ehxA virulence genes as assessed by PCR. An approximate 4 log10 inactivation of E. coli O157:H7 occurred at 5 °C in the presence of phage FAHEc1 at >10(7) PFU/ml in broth in vitro. On thinly sliced beef pieces incubated at 37 °C, a > 2.7 log10 reduction occurred with 3.2 × 10(7) PFU/4 cm(2) meat piece. At lower phage concentrations (10(3)-10(4) PFU/4 cm(2) pi...

Synbiotic impact of tagatose on viability of Lactobacillus rhamnosus strain GG mediated by the phosphotransferase system (PTS).

Food Microbiology — Sat, 15 Jun 2013 22:50:04 +0100

Authors: Koh JH, Choi SH, Park SW, Choi NJ, Kim Y, Kim SH Abstract Synbiotics, the combination of prebiotics and probiotics, has been shown to produce synergistic effects that promote gastrointestinal well-being of host. Tagatose is a low calorie food ingredient with putative health-promoting benefits. Herein, we investigated its synbiotic impact on the viability of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG and the potential mechanism involved. Tagatose, as a synbiotic substrate, enhanced the growth of L. casei 01 and L. rhamnosus strain GG compared to other prebiotics. Other gut-indigenous such as Clostridium spp. readily utilized fructooligosaccharide (FOS), the most widely used functional prebiotics, but not tagatose. Additionally, tagatose enhanced probioti...

Fate of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during storage of fermented green table olives in brine.

Food Microbiology — Sat, 15 Jun 2013 22:50:04 +0100

Authors: Argyri AA, Lyra E, Panagou EZ, Tassou CC Abstract The survival of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during the storage of fermented green table olives cv. Halkidiki in brine was studied in parallel with the evolution of lactic acid bacteria (LAB), yeasts and pH. The olives were previously fermented with a starter culture (a potential probiotic strain of Lactobacillus pentosus B281 - starter process) or with the indigenous microbiota (control). After the end of fermentation, olives were placed in brine, inoculated with a cocktail of 5 strains of E. coli O157:H7, 5 strains of L. monocytogenes and 4 strains of S. Enteritidis, with a final concentration in the brine of ca. 7.0 log CFU/ml, and subsequently packaged in polyethylene pou...

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Antibiofilm effect of plant derived antimicrobials on Listeria monocytogenes.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

Authors: Upadhyay A, Upadhyaya I, Kollanoor-Johny A, Venkitanarayanan K Abstract The present study investigated the efficacy of sub-inhibitory concentrations (SICs, concentrations not inhibiting bacterial growth) and bactericidal concentrations (MBCs) of four, generally recognized as safe (GRAS), plant-derived antimicrobials (PDAs) in inhibiting Listeria monocytogenes (LM) biofilm formation and inactivating mature LM biofilms, at 37, 25 and 4 °C on polystyrene plates and stainless-steel coupons. In addition, the effect of SICs of PDAs on the expression of LM genes critical for biofilm synthesis was determined by real-time quantitative PCR. The PDAs and their SICs used for inhibition of biofilm were trans-cinnamaldehyde (TC 0.50, 0.75 mM), carvacrol (CR 0.50, 0.65 mM), thymol (T...

Effects of some oil-born yeasts on the sensory characteristics of Italian virgin olive oil during its storage.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

Authors: Zullo BA, Cioccia G, Ciafardini G Abstract The olive oil microbiota, mainly composed of yeasts, is associated with the suspended fraction of freshly produced olive oils. Some olive oil yeasts are considered useful as they are able to hydrolyse the bitter tasting secoiridoid compound of the oil, whereas others are considered harmful as they can damage the quality of the oil. Present research demonstrated the influence of some yeast strains belonging to Candida adriatica, Candida diddensiae and Candida wickerhamii species on the olive oil sensory characteristics during its storage. All the tested yeasts survived in the inoculated extra virgin olive oil and, after four months of storage, the suspended yeast cells recovered from the olive oil varied between 50% and 80% of the ...

High pressure homogenization vs heat treatment: Safety and functional properties of liquid whole egg.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

Authors: Patrignani F, Vannini L, Sado Kamdem SL, Hernando I, Marco-Molés R, Guerzoni ME, Lanciotti R Abstract This research investigated the potential of multi-pass homogenization treatment for the inactivation of Salmonella enterica serovar Enteritidis inoculated at different levels in liquid whole egg (LWE) comparing the efficacy of this treatment with a traditional thermal one performed at 65 °C. Moreover, the effects of high pressure treatment (HPH) on structural and functional properties such as viscosity, microstructure and foaming abilities of LWE were investigated. The data obtained suggested that the multi-pass high pressure treatment at 100 MPa of S. enterica serovar Enteritidis inoculated in LWE at 7 and 4 log CFU/ml resulted in a first order inactivation kinetic, w...

Microbiological quality of chicken- and pork-based street-vended foods from Taichung, Taiwan, and Laguna, Philippines.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

Authors: Manguiat LS, Fang TJ Abstract The microbiological quality of chicken- and pork-based street-food samples from Taichung, Taiwan's night markets (50) and Laguna, Philippines' public places (69) was evaluated in comparison to a microbiological guideline for ready-to-eat foods. Different bacterial contamination patterns were observed between 'hot-grilled' and 'cold cooked/fried' food types from the two sampling locations with 'hot grilled' foods generally showing better microbiological quality. Several samples were found to be unsatisfactory due to high levels of aerobic plate count, coliform, Escherichia coli, and Staphylococcus aureus. The highest counts obtained were 8.2 log cfu g(-1), 5.4 log cfu g(-1), 4.4 log cfu g(-1), and 3.9 log cfu g(-1), respectively, suggest...

Role of initial contamination levels, biofilm maturity and presence of salt and fat on desiccation survival of Listeria monocytogenes on stainless steel surfaces.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

In conclusion, L. monocytogenes desiccation survival can be greatly reduced by preventing presence of mature biofilms and salty or fatty soils on food contact surfaces. PMID: 23764219 [PubMed - in process] (Source: Food Microbiology)

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Hurdle enhancement of slightly acidic electrolyzed water antimicrobial efficacy on Chinese cabbage, lettuce, sesame leaf and spinach using ultrasonication and water wash.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

This study examined the microbicidal activity of SAEW (pH 5.2-5.5, oxidation reduction potential 500-600 mV, available chlorine concentration 21-22 mg/l) on Chinese cabbage, lettuce, sesame leaf and spinach, four common fresh vegetables in Korea under same laboratory conditions. Subsequently, effects of ultrasonication and water wash to enhance the sanitizing efficacy of SAEW were studied, separately. Finally, an optimized simple and easy approach consisting of simultaneous SAEW treatment with ultrasonication (3 min) followed by water wash (150 rpm, 1 min) was developed (SAEW + US-WW). This newly developed hurdle treatment significantly enhanced the microbial reductions compared to SAEW treatment alone, SAEW treatment with ultrasonication (SAEW + US) and SAEW treatment followed by...

Acetobacter malorum and Acetobacter cerevisiae identification and quantification by Real-Time PCR with TaqMan-MGB probes.

Food Microbiology — Sat, 15 Jun 2013 22:50:03 +0100

Authors: Valera MJ, Torija MJ, Mas A, Mateo E Abstract The identification and quantification of Acetobacter malorum and Acetobacter cerevisiae in wine and vinegar were performed using the Real-Time PCR (RT-PCR) with two TaqMan-MGB probes designed to amplify the internal transcribed spacer (ITS) region between the 16S-23S rRNA genes. The primers and probes were highly specific, with a detection limit of 10(2) cells/ml for both species, and the efficiency of the technique was >80%. The RT-PCR technique with these two new TaqMan-MGB probes, together with the five (Acetobacter aceti, Acetobacter pasteurianus, Gluconobacter oxydans, Gluconacetobacter hansenii and Gluconacetobacter europaeus) that are already available (Torija et al., 2010), were validated on known concentrations of ...

Diversity of thermophilic bacteria in raw, pasteurized and selectively-cultured milk, as assessed by culturing, PCR-DGGE and pyrosequencing.

Food Microbiology — Sat, 15 Jun 2013 22:50:02 +0100

Authors: Delgado S, Rachid CT, Fernández E, Rychlik T, Alegría A, Peixoto RS, Mayo B Abstract Thermophilic lactic acid bacteria (LAB) species, such as Streptococcus thermophilus, Lactobacillus delbrueckii and Lactobacillus helveticus, enjoy worldwide economic importance as dairy starters. To assess the diversity of thermophilic bacteria in milk, milk samples were enriched in thermophilic organisms through a stepwise procedure which included pasteurization of milk at 63 °C for 30 min (PM samples) and pasteurization followed by incubation at 42 °C for 24 h (IPM samples). The microbial composition of these samples was analyzed by culture-dependent (at 42 °C) and culture-independent (PCR-DGGE and pyrosequencing of 16S rRNA gene amplicons) microbial techniques. The results wer...

Physical sample structure as predictive factor in growth modeling of Listeria innocua in a white cheese model system.

Food Microbiology — Sat, 15 Jun 2013 22:50:02 +0100

Authors: Møller SM, Bertram HC, Andersen U, Lillevang SK, Rasmussen A, Hansen TB Abstract Growth of Listeria innocua at 9 °C was investigated in white cheeses manufactured from ultra-filtrate milk concentrate added varying amounts of skimmed milk powder, NaCl and glucono-delta-lactone. Characterization of the white cheese structures was performed using nuclear magnetic resonance (NMR) T2 relaxation parameters (relaxation times constants, relative areas and width of peaks) and their applicability as predictive factors for maximum specific growth rate, √μmax and log-increase in 6 weeks of L. innocua was evaluated by polynomial modeling. Inclusion of NMR parameters was able to increase the goodness-of-fit of two basic models; one having pH, undissociated gluconic acid (GAu, mM)...

Carbon-rich wastes as feedstocks for biodegradable polymer (polyhydroxyalkanoate) production using bacteria.

Advances in Applied Microbiology — Sat, 15 Jun 2013 16:55:02 +0100

Authors: Nikodinovic-Runic J, Guzik M, Kenny ST, Babu R, Werker A, O Connor KE Abstract Research into the production of biodegradable polymers has been driven by vision for the most part from changes in policy, in Europe and America. These policies have their origins in the Brundtland Report of 1987, which provides a platform for a more sustainable society. Biodegradable polymers are part of the emerging portfolio of renewable raw materials seeking to deliver environmental, social, and economic benefits. Polyhydroxyalkanoates (PHAs) are naturally-occurring biodegradable-polyesters accumulated by bacteria usually in response to inorganic nutrient limitation in the presence of excess carbon. Most of the early research into PHA accumulation and technology development for industrial-sc...

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The natural history of yeast prions.

Advances in Applied Microbiology — Sat, 15 Jun 2013 16:55:02 +0100

Authors: Tuite MF Abstract Although prions were first discovered through their link to severe brain degenerative diseases in animals, the emergence of prions as regulators of the phenotype of the yeast Saccharomyces cerevisiae and the filamentous fungus Podospora anserina has revealed a new facet of prion biology. In most cases, fungal prions are carried without apparent detriment to the host cell, representing a novel form of epigenetic inheritance. This raises the question of whether or not yeast prions are beneficial survival factors or actually gives rise to a "disease state" that is selected against in nature. To date, most studies on the impact of fungal prions have focused on laboratory-cultivated "domesticated" strains of S. cerevisiae. At least eight prions have now been d...

The clinical importance of fungal biofilms.

Advances in Applied Microbiology — Sat, 15 Jun 2013 16:55:02 +0100

Authors: Ramage G, Williams C Abstract Fungal biofilms have become an increasingly important clinical problem. The widespread use of antibiotics, frequent use of indwelling medical devices, and a trend toward increased patient immunosuppression have resulted in a creation of opportunity for clinically important yeasts and molds to form biofilms. This review will discuss the diversity and importance of fungal biofilms in the context of clinical medicine, provide novel insights into the clinical management of fungal biofilm infection, present evidence why these structures are recalcitrant to antifungal therapy, and discuss how our knowledge and understanding may lead to novel therapeutic intervention. PMID: 23763758 [PubMed - in process] (Source: Advances in Applied Microbiology)

Sensing and Adapting to Anaerobic Conditions by Staphylococcus aureus.

Advances in Applied Microbiology — Sat, 15 Jun 2013 16:55:02 +0100

Authors: Hall JW, Ji Y Abstract A highly adaptive commensal organism, Staphylococcus aureus, possesses an array of genes that allow the bacterium to survive and grow in a wide variety of niches. Several of these niches are known to be or become anaerobic during the course of an infection; additionally, biofilms that develop, commonly on implanted medical devices, become anaerobic. The metabolic capability of S. aureus provides the organism with the essential nutrients needed to continue to grow, divide, and thwart the host immune system in the presence or absence of oxygen. In order to utilize the ATP-producing pathways and maintain cellular health S. aureus has evolved a series of regulatory systems that regulate these ATP-producing pathways. In this review, we discuss the protein...

Inflammatory parameters and prediction of prognosis in infective endocarditis

BMC Infectious Diseases — Sat, 15 Jun 2013 04:00:00 +0100

Conclusions: For the first time, this study shows that in IE, an initial value of PCT > 0.5 ng/mL is a useful predictor of poor outcome, i.e. death or serious infectious complications. PCT > 0.5 ng/mL should raise the suspicion of Staphylococcus aureus as the etiological pathogen, whereas PCT levels < 0.5 ng/mL make staphylococcal infection unlikely. (Source: BMC Infectious Diseases)

Quantitative immunophenotypic analysis of APCs involved in ectromelia virus antigen presentation in BALB/c and C57BL/6 mice

FEMS Immunology and Medical Microbiology — Sat, 15 Jun 2013 04:00:00 +0100

Energy, ecology and the distribution of microbial life.

Biol Sci Space — Fri, 14 Jun 2013 19:05:02 +0100

Authors: Macalady JL, Hamilton TL, Grettenberger CL, Jones DS, Tsao LE, Burgos WD Abstract Mechanisms that govern the coexistence of multiple biological species have been studied intensively by ecologists since the turn of the nineteenth century. Microbial ecologists in the meantime have faced many fundamental challenges, such as the lack of an ecologically coherent species definition, lack of adequate methods for evaluating population sizes and community composition in nature, and enormous taxonomic and functional diversity. The accessibility of powerful, culture-independent molecular microbiology methods offers an opportunity to close the gap between microbial science and the main stream of ecological theory, with the promise of new insights and tools needed to meet the grand cha...

Diarrhea among children in developing countries.

Adv Data — Fri, 14 Jun 2013 17:45:04 +0100

Authors: Nataro JP Abstract Diarrhea continues to stand among the most important causes of global morbidity and mortality in children under 5 years of age. Although the introduction of oral rehydration and other case-management strategies have reduced acute diarrhea fatalities, many of the survivors develop persistent diarrhea and/or deficiencies of growth and cognition. Thus understanding the true global burden of diarrhea requires attention to acute diarrhea as well is its sequelae. To understand the etiology of moderate to severe diarrhea among children in high mortality areas of sub-Saharan Africa and south Asia we performed a comprehensive case-control study of children under 5 years of age at seven sites. Each site employed an identical case-control study design and each util...

Does Microbicide Use in Consumer Products Promote Antimicrobial Resistance? A Critical Review and Recommendations for a Cohesive Approach to Risk Assessment

Microbial Drug Resistance — Fri, 14 Jun 2013 14:38:05 +0100

Microbial Drug Resistance , Vol. 0, No. 0. (Source: Microbial Drug Resistance)

Are Today's Doctors Too Scruffy?

Health News from Medical News Today — Fri, 14 Jun 2013 07:00:00 +0100

Scruffiness suggests lack of personal hygiene, argues senior doctor Personal view: Put your ties back on: scruffy doctors damage our reputation and imply declining standards of cleanliness Informal dress among doctors "erodes the image of doctors as responsible and competent" and "also intimates a lack of personal hygiene" argues a consultant microbiologist on bmj.com today. In 2007, the Department of Health said doctors should not wear ties in the interest of hospital hygiene... (Source: Health News from Medical News Today)

Analysis of essential amino acid residues for catalytic activity of cis-epoxysuccinate hydrolase from Bordetella sp. BK-52.

Applied Microbiology and Biotechnology — Fri, 14 Jun 2013 04:00:00 +0100

Authors: Bao W, Pan H, Zhang Z, Cheng Y, Xie Z, Zhang J, Li Y Abstract cis-Epoxysuccinate hydrolase (CESH) from Bordetella sp. BK-52, an epoxide hydrolase (EH), catalyzes the stereospecific hydrolysis of cis-epoxysuccinate to D(-)-tartrate. The enzyme, which shows no homology to other reported EHs, belongs to the DUF849 superfamily of prokaryotic proteins, which have unknown function. Metal composition analysis revealed that the CESH is a Zn(2+)-dependent enzyme with an approximately 1:1 molar ratio of zinc to enzyme. The results of an (18)O-labeling study suggest that the enzyme catalyzes epoxide hydrolysis by means of a one-step mechanism. We evaluated the relationship between the structure and function of the enzyme by means of sequence alignment, modeling, substrate binding, an...

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IFITM3 Restricts Reovirus Entry [Immunology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Reoviruses are double-stranded RNA viruses that infect the mammalian respiratory and gastrointestinal tract. Reovirus infection elicits production of type I interferons (IFNs), which trigger antiviral pathways through the induction of interferon-stimulated genes (ISGs). Although hundreds of ISGs have been identified, the functions of many of these genes are unknown. The interferon-inducible transmembrane (IFITM) proteins are one class of ISGs that restrict the cell entry of some enveloped viruses, including influenza A virus. One family member, IFITM3, localizes to late endosomes, where reoviruses undergo proteolytic disassembly; therefore, we sought to determine whether IFITM3 also restricts reovirus entry. IFITM3-expressing cell lines were less susceptible to infection by reovirus, as th...

Characterization of Egg White OVAX [Microbiology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Ovalbumin family contains three proteins with high sequence similarity: ovalbumin, ovalbumin-related protein Y (OVAY), and ovalbumin-related protein X (OVAX). Ovalbumin is the major egg white protein with still undefined function, whereas the biological activity of OVAX and OVAY has not yet been explored. Similar to ovalbumin and OVAY, OVAX belongs to the ovalbumin serine protease inhibitor family (ov-serpin). We show that OVAX is specifically expressed by the magnum tissue, which is responsible for egg white formation. OVAX is also the main heparin-binding protein of egg white. This glycoprotein with a predicted reactive site at Lys367-His368 is not able to inhibit trypsin, plasmin, or cathepsin G with or without heparin as a cofactor. Secondary structure of OVAX is similar to that of ova...

ATP Enhances INDOPY-1-mediated Inhibition of HIV-1 RT [Microbiology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Nucleotide-competing reverse transcriptase inhibitors were shown to bind reversibly to the nucleotide-binding site of the reverse transcriptase (RT) enzyme of human immunodeficiency virus type 1 (HIV-1). Here, we show that the presence of ATP can enhance the inhibitory effects of the prototype compound INDOPY-1. We employed a combination of cell-free and cell-based assays to shed light on the underlying molecular mechanism. Binding studies and site-specific footprinting experiments demonstrate the existence of a stable quaternary complex with HIV-1 RT, its nucleic acid substrate, INDOPY-1, and ATP. The complex is frozen in the post-translocational state that usually accommodates the incoming nucleotide substrate. Structure-activity relationship studies show that both the base and the phosp...

CYP121 Specificity [Microbiology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

We report an investigation of the substrate and reaction specificities of CYP121 involving analysis of the interaction between CYP121 and 14 cYY analogues with various modifications of the side chains or the diketopiperazine (DKP) ring. Spectral titration experiments show that CYP121 significantly bound only cyclodipeptides with a conserved DKP ring carrying two aryl side chains in l-configuration. CYP121 did not efficiently or selectively transform any of the cYY analogues tested, indicating a high specificity for cYY. The molecular determinants of this specificity were inferred from both crystal structures of CYP121-analog complexes solved at high resolution and solution NMR spectroscopy of the analogues. Bound cYY or its analogues all displayed a similar set of contacts with CYP121 resi...

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Influenza HA Cleavage Activation by Kallikreins [Molecular Bases of Disease]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

In this study, we have determined that the kallikrein-related peptidases 5 and 12 are secreted from the human respiratory tract and have the ability to cleave and activate HA from the H1, H2, and H3 subtypes. Each peptidase appears to have a preference for particular influenza subtypes, with kallikrein 5 cleaving the H1 and H3 subtypes most efficiently and kallikrein 12 cleaving the H1 and H2 subtypes most efficiently. Cleavage analysis using HA cleavage site peptide mimics revealed that the amino acids neighboring the arginine cleavage site affect cleavage efficiency. Additionally, the thrombolytic zymogens plasminogen, urokinase, and plasma kallikrein have all been shown to cleave and activate influenza but are found circulating mainly as inactive precursors. Kallikrein 5 and kallikrein ...

Rewiring the Fungal Ribosomal Protein Regulon [Microbiology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

The genes encoding the ribosomal proteins of fungi form a regulon whose expression is enhanced under good growth conditions and down-regulated under starvation conditions. The fungal pathogen Candida albicans contains an evolutionarily ancient control circuit for this regulon where a heteromer made up of the transcription regulators Ifh1 (interacts with Forkhead 1) and Fhl1 (Forkhead-like 1) is targeted to the ribosomal protein genes by the DNA binding factor Tbf1. In the more recently evolved circuit in the model yeast Saccharomyces cerevisiae (Sc), the generalist repressor-activator protein Rap1 now directs the Ifh1-Fhl1 module to the ribosomal protein genes. Even though overall sequence similarity is low for the respective Fhl1 and Ifh1 subunits, in both species, the Ifh1 protein links ...

Aggregation of TasA on a Surface and in Solution [Molecular Biophysics]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Biofilms are surface-associated groups of microbial cells that are embedded in an extracellular matrix (ECM). The ECM is a network of biopolymers, mainly polysaccharides, proteins, and nucleic acids. ECM proteins serve a variety of structural roles and often form amyloid-like fibers. Despite the extensive study of the formation of amyloid fibers from their constituent subunits in humans, much less is known about the assembly of bacterial functional amyloid-like precursors into fibers. Using dynamic light scattering, atomic force microscopy, circular dichroism, and infrared spectroscopy, we show that our unique purification method of a Bacillus subtilis major matrix protein component results in stable oligomers that retain their native α-helical structure. The stability of these oligomers ...

Central Metabolism and Osmoadaptation in C. salexigens [Microbiology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Bacterial osmoadaptation involves the cytoplasmic accumulation of compatible solutes to counteract extracellular osmolarity. The halophilic and highly halotolerant bacterium Chromohalobacter salexigens is able to grow up to 3 m NaCl in a minimal medium due to the de novo synthesis of ectoines. This is an osmoregulated pathway that burdens central metabolic routes by quantitatively drawing off TCA cycle intermediaries. Consequently, metabolism in C. salexigens has adapted to support this biosynthetic route. Metabolism of C. salexigens is more efficient at high salinity than at low salinity, as reflected by lower glucose consumption, lower metabolite overflow, and higher biomass yield. At low salinity, by-products (mainly gluconate, pyruvate, and acetate) accumulate extracellularly. Using [1...

Structure of MycP1 [Enzymology]

Journal of Biological Chemistry — Fri, 14 Jun 2013 04:00:00 +0100

Mycobacteria use specialized type VII (ESX) secretion systems to export proteins across their complex cell walls. Mycobacterium tuberculosis encodes five nonredundant ESX secretion systems, with ESX-1 being particularly important to disease progression. All ESX loci encode extracellular membrane-bound proteases called mycosins (MycP) that are essential to secretion and have been shown to be involved in processing of type VII-exported proteins. Here, we report the first x-ray crystallographic structure of MycP1(24–407) to 1.86 Å, defining a subtilisin-like fold with a unique N-terminal extension previously proposed to function as a propeptide for regulation of enzyme activity. The structure reveals that this N-terminal extension shows no structural similarity to previously characterized ...

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The Chennai Declaration: India's landmark national commitment to antibiotic stewardship demonstrates that 'truth alone triumphs'