MedWorm: Microbiology

Effects of ergosterol on the structure and activity of Neurospora mitochondrial porin in liposomes

Canadian Journal of Microbiology — Fri, 20 Nov 2009 16:15:02 +0100

Denice C. Bay and Deborah A. Court - Mitochondrial porins (also known as voltage-dependent anion-selective channels (VDACs)) regulate and contribute to cellular metabolism. These proteins copurify with sterols, and some purified forms of... (Source: Canadian Journal of Microbiology)

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Silencing of a putative immunophilin gene in the cattle tick Rhipicephalus (Boophilus) microplus increases the infection rate of Babesia bovis in larval progeny

Parasites and Vectors — Fri, 20 Nov 2009 00:00:00 +0100

Conclusion: The silencing of the Imnp, Spi or Lpc genes decreased the fitness of R. microplus females fed on a calf during acute B. bovis infection. The Imnp gene data suggest that this putative immunophilin gene is involved in the defense system of R. microplus against B. bovis and may play a role in controlling the protozoan infection in tick ovaries and larval progeny. (Source: Parasites and Vectors)

A fatal case of spinal tuberculosis mistaken for metastatic lung cancer: recalling ancient Pott's disease

Annals of Clinical Microbiology and Antimicrobials — Fri, 20 Nov 2009 00:00:00 +0100

Conclusion: The rapid diagnosis of spinal TB demands a high index of suspicion and expertise regarding the appropriate diagnostic procedures. Due to the devastating consequences of a missed diagnosis, Mycobacterium tuberculosis should be considered early in every case of spondylitis, intraspinal or paravertebral abscess. The presence of certain alarm signals like a prolonged history of progressive back pain, constitutional symptoms or pulmonary nodules on a chest radiograph, particularly in the upper lobes, may guide the clinical suspicion. (Source: Annals of Clinical Microbiology and Antimicrobials)

Kocuria SM1 controls vibriosis in rainbow trout (Oncorhynchus mykiss, Walbaum)

Journal of Applied Microbiology — Fri, 20 Nov 2009 00:00:00 +0100

Conclusions: Kocuria SM1 successfully controlled vibriosis in rainbow trout, and the mode of action reflected stimulation of the host innate immune system.Significance and Impact of the Study: Probiotics can contribute a significant role in fish disease control strategies, and their use may replace some of the inhibitory chemicals currently used in fish farms. (Source: Journal of Applied Microbiology)

Specific detection of Arcobacter spp. in estuarine waters of Southern Italy by PCR and fluorescent in situ hybridization

Letters in Applied Microbiology — Fri, 20 Nov 2009 00:00:00 +0100

Conclusions: Culturable and nonculturable forms of Arcobacter in the estuarine environment were present. PCR assays were more sensitive than traditional culture in detecting Arcobacter butzleri and A. cryaerophilus. FISH comparatively to PCR technique may provide information about cell morphology and viability of single cells.Significance and Impact of the Study: Our investigation indicates the existence of an environmental reservoir of potential pathogenic arcobacters in an estuarine Italian area, which may survive under a viable but not culturable state. (Source: Letters in Applied Microbiology)

Competitive activation of the Escherichia coli argO gene coding for an arginine exporter by the transcriptional regulators Lrp and ArgP

Molecular Microbiology — Fri, 20 Nov 2009 00:00:00 +0100

In vivo and in vitro analyses indicate that transcription of the argO gene coding for an arginine exporter is regulated by the global transcriptional regulator Lrp, an effect that went by unnoticed in previous genome-scale screenings of the Lrp regulatory network in Escherichia coli. Lrp activates the argO promoter fourfold; exogenous leucine antagonizes, but does not completely eliminate this effect. Activation by Lrp interferes with the previously demonstrated activation of the argO promoter by ArgP. This interference results from the mutual inhibitory binding of the two activators to overlapping targets. As a consequence, each regulator acts more potently in the absence of the other. Dimeric Lrp binds cooperatively to at least three regularly spaced semi-palindromic binding sites. Leuci...

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The Tat pathway of plant pathogen Dickeya dadantii 3937 contributes to virulence and fitness

FEMS Microbiology Letters — Fri, 20 Nov 2009 00:00:00 +0100

Protein secretion plays a very important role in the virulence of the bacterium Dickeya dadantii, the causative agent of soft rot disease, in a wide range of plant species. We studied the contribution of the twin-arginine translocation (Tat) protein system to the adaptation of D. dadantii 3937 to different growth conditions and to the interaction with the plant host. First, a list of 44 putative Tat substrates was obtained using bioinformatic programs taking advantage of the availability of the complete sequence of this bacterium. Second, a tatC mutant strain was constructed and analysed. The mutant displayed a pleiotropic phenotype, showing limited growth in an iron-depleted medium, higher sensitivity to copper, reduced motility on soft agar plates and attenuated virulence in witloof chic...

Overexpression and characterization of medium-chain-length polyhydroxyalkanoate granule bound polymerases from Pseudomonas putida GPo1

Microbial Cell Factories — Thu, 19 Nov 2009 00:00:00 +0100

Conclusion: The kinetic properties and substrate ranges were determined for both granule bound polymerases. PhaC1 and PhaC2 exhibited different characteristics in granule release and activity profiles, suggesting that there are substantial functional differences between granule bound PhaC1 and PhaC2. (Source: Microbial Cell Factories)

Rapid cleavage of RNA by RNase E in the absence of 5' monophosphate stimulation

Molecular Microbiology — Thu, 19 Nov 2009 00:00:00 +0100

The best characterized pathway for the initiation of mRNA degradation in Escherichia coli involves the removal of the 5'-terminal pyrophosphate to generate a monophosphate group that stimulates endonucleolytic cleavage by RNase E. We show here however, using well-characterized oligonucleotide substrates and mRNA transcripts, that RNase E can cleave certain RNAs rapidly without requiring a 5'-monophosphorylated end. Moreover, the minimum substrate requirement for this mode of cleavage, which can be categorized as 'direct' or 'internal' entry, appears to be multiple single-stranded segments in a conformational context that allows their simultaneous interaction with RNase E. While previous work has alluded to the existence of a 5' end-independent mechanism of mRNA degradation, the relative si...

Influence of RpoS, cAMP-receptor protein, and ppGpp on expression of the opgGH operon and osmoregulated periplasmic glucan content of Salmonella enterica serovar Typhimurium

Canadian Journal of Microbiology — Wed, 18 Nov 2009 16:26:39 +0100

Cristina S. Costa, Ramón A. Pizarro, and Dora N. Antón - A transcriptional fusion (opgG1::MudJ) to the opgGH operon of Salmonella enterica serovar Typhimurium (S. Typhimurium) LT2, isolated by resistance to mecillinam, was used to study... (Source: Canadian Journal of Microbiology)

A Tail of Tetherin: How Pandemic HIV-1 Conquered the World.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:37 +0100

Authors: Gupta RK, Towers GJ The study of successful versus failed zoonotic infections may provide important clues of how viral infection is naturally prevented. In this issue of Cell Host & Microbe, a collaborative group led by Frank Kirchhoff uncovers an important piece of the pandemic HIV-1 puzzle. PMID: 19917491 [PubMed - in process] (Source: Cell Host and Microbe)

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Jenner's Irony: Cowpox Taps into T Cell Evasion.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:34 +0100

Authors: Wilkinson GW, Lehner PJ CPXV12 is the first poxvirus gene product demonstrated to inhibit the transporter associated with antigen processing (TAP). This cowpox virus function acts in concert with a second gene product, CPXV203, to efficiently suppress MHC class I antigen presentation and enhance in vivo virulence. PMID: 19917492 [PubMed - in process] (Source: Cell Host and Microbe)

How aging compromises antiviral defenses: a role for imbalanced innate cytokine production.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:32 +0100

Authors: Guiton R, Dalod M Aging causes enhanced susceptibility to viral infections. Stout-Delgado et al. (2009) report increased IL-17A production but reduced type I interferon levels in old mice infected by herpes viruses. This imbalance between proinflammatory and antiviral innate cytokine responses causes immunopathology and compromises virus control, which together lead to death by liver failure. PMID: 19917493 [PubMed - in process] (Source: Cell Host and Microbe)

A bacterial pathogen flips the riboswitch.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:29 +0100

Authors: Xayarath B, Freitag NE Riboswitches are RNA structures traditionally viewed as acting in cis to regulate downstream gene expression in bacteria. In a recent issue of Cell, Loh and colleagues report on the ability of a riboswitch to act in trans to modulate the expression of a critical bacterial virulence regulator. PMID: 19917494 [PubMed - in process] (Source: Cell Host and Microbe)

War and Peace between Microbes: HIV-1 Interactions with Coinfecting Viruses.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:27 +0100

Authors: Lisco A, Vanpouille C, Margolis L HIV-1 disrupts the homeostatic equilibrium between the host and coinfecting microbes, facilitating reactivation of persistent viruses and invasion by new viruses. These viruses usually accelerate HIV disease but occasionally create conditions detrimental for HIV-1. Understanding these phenomena may lead to anti-HIV-1 strategies that specifically target interactions between HIV-1 and coinfecting viruses. PMID: 19917495 [PubMed - in process] (Source: Cell Host and Microbe)

Tetherin-Driven Adaptation of Vpu and Nef Function and the Evolution of Pandemic and Nonpandemic HIV-1 Strains.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:24 +0100

Authors: Sauter D, Schindler M, Specht A, Landford WN, Münch J, Kim KA, Votteler J, Schubert U, Bibollet-Ruche F, Keele BF, Takehisa J, Ogando Y, Ochsenbauer C, Kappes JC, Ayouba A, Peeters M, Learn GH, Shaw G, Sharp PM, Bieniasz P, Hahn BH, Hatziioannou T, Kirchhoff F Vpu proteins of pandemic HIV-1 M strains degrade the viral receptor CD4 and antagonize human tetherin to promote viral release and replication. We show that Vpus from SIVgsn, SIVmus, and SIVmon infecting Cercopithecus primate species also degrade CD4 and antagonize tetherin. In contrast, SIVcpz, the immediate precursor of HIV-1, whose Vpu shares a common ancestry with SIVgsn/mus/mon Vpu, uses Nef rather than Vpu to counteract chimpanzee tetherin. Human tetherin, however, is resistant to Nef and thus poses a signific...

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Two mechanistically distinct immune evasion proteins of cowpox virus combine to avoid antiviral CD8 T cells.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:22 +0100

Authors: Byun M, Verweij MC, Pickup DJ, Wiertz EJ, Hansen TH, Yokoyama WM Downregulation of MHC class I on the cell surface is an immune evasion mechanism shared by many DNA viruses, including cowpox virus. Previously, a cowpox virus protein, CPXV203, was shown to downregulate MHC class I. Here we report that CPXV12 is the only other MHC class I-regulating protein of cowpox virus and that it uses a mechanism distinct from that of CPXV203. Whereas CPXV203 retains fully assembled MHC class I by exploiting the KDEL-mediated endoplasmic reticulum retention pathway, CPXV12 binds to the peptide-loading complex and inhibits peptide loading on MHC class I molecules. Viruses deleted of both CPXV12 and CPXV203 demonstrated attenuated virulence in a CD8 T cell-dependent manner. These data demonst...

Cowpox virus inhibits the transporter associated with antigen processing to evade T cell recognition.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:19 +0100

Authors: Alzhanova D, Edwards DM, Hammarlund E, Scholz IG, Horst D, Wagner MJ, Upton C, Wiertz EJ, Slifka MK, Früh K Cowpox virus encodes an extensive array of putative immunomodulatory proteins, likely contributing to its wide host range, which includes zoonotic infections in humans. Unlike Vaccinia virus, cowpox virus prevents stimulation of CD8(+) T cells, a block that correlated with retention of MHC class I in the endoplasmic reticulum by the cowpox virus protein CPXV203. However, deletion of CPXV203 did not restore MHC class I transport or T cell stimulation. Here, we demonstrate the contribution of an additional viral protein, CPXV12, which interferes with MHC class I/peptide complex formation by inhibiting peptide translocation by the transporter associated with antigen pr...

Aging Promotes Neutrophil-Induced Mortality by Augmenting IL-17 Production during Viral Infection.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:17 +0100

Authors: Stout-Delgado HW, Du W, Shirali AC, Booth CJ, Goldstein DR Morbidity and mortality associated with viral infections increase with age, although the underlying mechanisms are unclear. Here, we investigated whether aging alters inflammatory responses during systemic viral infection and thereby contributes to virus-induced death. We found that infection of aged mice with systemic herpes viruses led to rapid increases in serum IL-17, neutrophil activation, and mortality due to hepatocyte necrosis. In contrast, all young mice survived infection, displaying weaker IL-17 induction and neutrophil activation. Natural killer T (NKT) cells isolated from the livers of aged mice produced more IL-17 than did young cells, and adoptively transferred aged NKT cells induced liver injury in youn...

Induced ER Chaperones Regulate a Receptor-like Kinase to Mediate Antiviral Innate Immune Response in Plants.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:14 +0100

Authors: Caplan JL, Zhu X, Mamillapalli P, Marathe R, Anandalakshmi R, Dinesh-Kumar SP Mounting an effective innate immune response against pathogens requires the rapid and global reprogramming of host cellular processes. Here we employed complementary proteomic methods to identify differentially regulated proteins early during a plant's defense response. Besides defense-related proteins, constituents of the largest category of upregulated proteins were cytoplasmic- and ER-residing molecular chaperones. Investigating the significance of upregulated ER chaperones, we find that silencing of ER-resident protein disulfide isomerases NbERp57 and NbP5 and the calreticulins NbCRT2 and NbCRT3 led to partial loss of N immune receptor-mediated defense against Tobacco mosaic virus (TMV). Furtherm...

Inflammatory Monocytes Facilitate Adaptive CD4 T Cell Responses during Respiratory Fungal Infection.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:11 +0100

Authors: Hohl TM, Rivera A, Lipuma L, Gallegos A, Shi C, Mack M, Pamer EG Aspergillus fumigatus, a ubiquitous fungus, causes invasive disease in immunocompromised humans. Although monocytes and antigen-specific CD4 T cells contribute to defense against inhaled fungal spores, how these cells interact during infection remains undefined. Investigating the role of inflammatory monocytes and monocyte-derived dendritic cells during fungal infection, we find that A. fumigatus infection induces an influx of chemokine receptor CCR2- and Ly6C-expressing inflammatory monocytes into lungs and draining lymph nodes. Depletion of CCR2(+) cells reduced A. fumigatus conidial transport from lungs to draining lymph nodes, abolished CD4 T cell priming following respiratory challenge, and impaired pulmonar...

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Antibodies against a Tick Protein, Salp15, Protect Mice from the Lyme Disease Agent.

Cell Host and Microbe — Wed, 18 Nov 2009 12:10:08 +0100

Authors: Dai J, Wang P, Adusumilli S, Booth CJ, Narasimhan S, Anguita J, Fikrig E Traditionally, vaccines directly target a pathogen or microbial toxin. Lyme disease, caused by Borrelia burgdorferi, is a tick-borne illness for which a human vaccine is not currently available. B. burgdorferi binds a tick salivary protein, Salp15, during transmission from the vector, and this interaction facilitates infection of mice. We now show that Salp15 antiserum significantly protected mice from B. burgdorferi infection. Salp15 antiserum also markedly enhanced the protective capacity of antibodies against B. burgdorferi antigens, such as OspA or OspC. Mice actively immunized with Salp15 were also significantly protected from tick-borne Borrelia. In vitro assays showed that Salp15 antiserum increase...

Very early acetaldehyde production by industrial Saccharomyces cerevisiae strains: a new intrinsic character.

Applied Microbiology and Biotechnology — Wed, 18 Nov 2009 00:00:00 +0100

Authors: Cheraiti N, Guezenec S, Salmon JM During a general survey of the acetaldehyde-producing properties of commercially available wine yeast strains, we discovered that, although final acetaldehyde production cannot be used as a discriminating factor between yeast strains, initial specific acetaldehyde production rates were of highly interest for classifying yeast strains. This parameter is very closely related to the growth- and fermentation-lag phase durations. We also found that this acetaldehyde early production occurs with very different extent between commercial active dry yeast strains during the rehydration phase and could partially explain the known variable resistance of yeast strains to sulfites. Acetaldehyde production appeared, therefore, as very precocious, strain-dep...

Description of the novel perchlorate-reducing bacteria Dechlorobacter hydrogenophilus gen. nov., sp. nov. and Propionivibrio militaris, sp. nov.

Applied Microbiology and Biotechnology — Wed, 18 Nov 2009 00:00:00 +0100

Authors: Thrash JC, Pollock J, Torok T, Coates JD Novel dissimilatory perchlorate-reducing bacteria (DPRB) were isolated from enrichments conducted under conditions different from those of all previously described DPRB. Strain LT-1(T) was enriched using medium buffered at pH 6.6 with 2-(N-morpholino)ethanesulfonic acid (MES) and had only 95% 16S rRNA gene identity with its closest relative, Azonexus caeni. Strain MP(T) was enriched in the cathodic chamber of a perchlorate-reducing bioelectrical reactor (BER) and together with an additional strain, CR (99% 16S rRNA gene identity), had 97% 16S rRNA gene identity with Propionivibrio limicola. The use of perchlorate and other electron acceptors distinguished strains MP(T) and CR from P. limicola physiologically. Strain LT-1(T) had differen...

A downstream process for production of a viable and stable Bacillus cereus aquaculture biological agent.

Applied Microbiology and Biotechnology — Wed, 18 Nov 2009 00:00:00 +0100

This study examines the development of suitable spore recovery, drying, formulation and tablet production from the fermentation product. Key criteria used for such downstream process unit evaluation included spore viability, recovery, spore balance, spore re-germination, product intermediate stability, end product stability and efficacy. A process flow sheet comprising vertical tube centrifugation, fluidised bed agglomeration and tablet pressing yielded a suitable product. The formulation included corn steep liquor and glucose to enhance subsequent spore re-germination. Viable spore recovery and spore balance closure across each of the process units was high (>70% and >99% respectively), with improvement in recovery possible by adoption of continuous processing at large scale. Spore ...

One gram of soil: a microbial biochemical gene library.

Antonie van Leeuwenhoek — Wed, 18 Nov 2009 00:00:00 +0100

Authors: Trevors JT One gram of soil is an immense biochemical gene library producing diverse genetic instructions, which have been present for almost 4 billion years on the Earth. There is sufficient DNA in 1 g of soil to extend 1,598 km. However, this is certainly an underestimate for fertile soils. Can the amount of genetic information contained in one g of soil be accurately estimated? The answer is not always definitive as the estimate depends on the particular g of soil being researched and the methods for DNA extraction, purification and quantification. Moreover, there is no such entity as a typical or average g of soil. Extraction of DNA from soil samples is never 100% efficient and can vary from a few mug to almost 200 mug DNA per g dry weight soil. However, estimates can be m...

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Isolation of Vibrio alginolyticus and Vibrio splendidus from captive-bred seahorses with disease symptoms.

Antonie van Leeuwenhoek — Wed, 18 Nov 2009 00:00:00 +0100

Authors: Balcázar JL, Gallo-Bueno A, Planas M, Pintado J Vibrio species isolated from diseased seahorses were characterized by PCR amplification of repetitive bacterial DNA elements (rep-PCR) and identified by 16S ribosomal RNA gene sequence analysis. The results demonstrated that Vibrio alginolyticus and Vibrio splendidus were predominant in the lesions of these seahorses. To our knowledge, this is the first time that these bacterial species have been associated with disease symptoms in captive-bred seahorses. PMID: 19921544 [PubMed - as supplied by publisher] (Source: Antonie van Leeuwenhoek)

Molecular intraspecific characterization of Photobacterium damselae ssp. damselae strains affecting cultured marine fish

Journal of Applied Microbiology — Wed, 18 Nov 2009 00:00:00 +0100

Conclusions: In this study, the techniques tested are confirmed as good tools for molecular typing, because they allow discrimination between P. damselae ssp. damselae strains isolated within the same outbreak. In addition, ERIC-PCR and REP-PCR methods were more adequate for rapid typing of P. damselae ssp. damselae than RAPD, allowing the discrimination at strain level.Significance and Impact of the Study: The results, in agreement with previous studies, confirmed the high intraspecific variability among isolated P. damselae ssp. damselae strains at both phenotypic and genetic levels. This suggests the existence of different clonal lineages that coexist in the same geographic area, within a short period of time (2[ndash]3 years). The discrimination at strain level can be useful to study t...

Analyses of binding sequences of the PhaR protein of Rhodobacter sphaeroides FJ1

FEMS Microbiology Letters — Wed, 18 Nov 2009 00:00:00 +0100

In this study, we determined that PhaR binds to an 11-bp palindromic sequence, 5'-CTGCN3GCAG-3', located at nucleotides [minus]69 to [minus]59 and [minus]97 to [minus]87 relative to the translation start site of phaP. Substitution of the three spacer nucleotides with any three or four nucleotides in this sequence had no effect on PhaR binding, but all other base deletions or substitutions in this sequence abolished its ability to bind PhaR both in vitro and in vivo. These results suggest that PhaR regulates the expression of phaP in R. sphaeroides FJ1. (Source: FEMS Microbiology Letters)

Regulation and secretion of Xanthomonas virulence factors

FEMS Microbiology Reviews — Wed, 18 Nov 2009 00:00:00 +0100

Plant pathogenic bacteria of the genus Xanthomonas cause a variety of diseases in economically important monocotyledonous and dicotyledonous crop plants worldwide. Successful infection and bacterial multiplication in the host tissue often depend on the virulence factors secreted including adhesins, polysaccharides, LPS and degradative enzymes. One of the key pathogenicity factors is the type III secretion system, which injects effector proteins into the host cell cytosol to manipulate plant cellular processes such as basal defense to the benefit of the pathogen. The coordinated expression of bacterial virulence factors is orchestrated by quorum-sensing pathways, multiple two-component systems and transcriptional regulators such as Clp, Zur, FhrR, HrpX and HpaR. Furthermore, virulence gene ...

Long-term flaxseed oil supplementation diet protects BALB/c mice against Streptococcus pneumoniae infection

Medical Microbiology and Immunology — Tue, 17 Nov 2009 23:51:09 +0100

Abstract Intense host immune response to infection contributes significantly to the pathology of pneumococcal pneumonia. Therefore, the regulation of host immune response is critical for the successful outcome of pneumonia in such patients. The aim of the present study was to investigate the effect of n-3 PUFA, i.e. flaxseed oil supplementation for short (4 weeks) as well as long (9 weeks) term, on the course of S. pneumoniae D39 serotype 2 infection in mice. The efficacy of flaxseed oil supplementation was investigated in terms of survival of animals and production of various inflammatory molecules (malondialdehyde, myeloperoxidase, nitric oxide) in the lung homogenate of animals. This was correlated with bacteriological and histopathological parameters. The immu...

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A plate method for screening of bacteria capable of degrading aliphatic nitriles.

Journal of Industrial Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Santoshkumar M, Nayak AS, Anjaneya O, Karegoudar TB A novel indicator plate method was developed for screening of aliphatic-nitrile-degrading bacteria. Isolated bacteria were tested for utilization of acetonitrile as sole source of carbon and nitrogen with the release of ammonia. The released ammonia causes increase of the pH of the medium. Phenol red indicator is used for detection of ammonia based on colour change of the indicator dye from red to pink. The liberation of ammonia from aliphatic-nitrile-utilizing bacteria is also studied in plates containing other indicators such as bromothymol blue and phenolphthalein. The usefulness of the indicator plate is demonstrated for bacteria that degrade certain aliphatic nitriles. Bacteria degrading nitriles as a nitrogen source can...

Hybridization in Endophyte Symbionts Alters Host Response to Moisture and Nutrient Treatments.

Microbial Ecology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Hamilton CE, Dowling TE, Faeth SH When a host organism is infected by a symbiont, the resulting symbiotum has a phenotype distinct from uninfected hosts. Genotypic interactions between the partners may increase phenotypic variation of the host at the population level. Neotyphodium is an asexual, vertically transmitted endophytic symbiont of grasses often existing in hybrid form. Hybridization in Neotyphodium rapidly increases the symbiotum's genomic content and is likely to increase the phenotypic variation of the host. This phenotypic variation is predicted to enhance host performance, especially in stressful environments. We tested this hypothesis by comparing the growth, survival, and resource allocation of hybrid and nonhybrid infected host plants exposed to controlled var...

Oxygen-induced expression of (6)-, (9)- and (12)-desaturase genes modulates fatty acid composition in Mucor rouxii.

Applied Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Ruenwai R, Cheevadhanarak S, Rachdawong S, Tanticharoen M, Laoteng K The effect of oxygen availability on the molecular mechanisms of fatty acid biosynthesis was investigated in Mucor rouxii, a Mucorale fungus capable of producing gamma-linolenic acid through perturbation of the gaseous environment. Shifting of the M. rouxii culture from anaerobic to aerobic conditions resulted in an increase of the biomass and total fatty acid content of the M. rouxii culture. In addition, the levels of unsaturated fatty acids were enhanced accompanied by a decrease in the levels of medium- and long-chain saturated fatty acids. These results correspond to the levels of expressions of the (9)-, (12)- and (6)-desaturases genes, all of which were coordinately up-regulated after the shift. The tr...

Engineering lower inhibitor affinities in beta-D: -xylosidase.

Applied Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

We report here the development of a two-tier high-throughput screen where the 1 degrees screen selects for activity (active/inactive screen) and the 2 degrees screen selects for a higher K (i(d-xylose)) and its subsequent use in screening approximately 5,900 members of an SXA enzyme library prepared using error-prone PCR. In one variant, termed SXA-C3, K (i(d-xylose)) is threefold and K (i(d-glucose)) is twofold that of wild-type SXA. C3 contains four amino acid mutations, and one of these, W145G, is responsible for most of the lost affinity for the monosaccharides. Experiments that probe the active site with ligands that bind only to subsite -1 or subsite +1 indicate that the changed affinity stems from changed affinity for D: -xylose in subsite +1 and not in subsite -1 of the two-subsite...

Identification in Agrobacterium tumefaciens of the D: -galacturonic acid dehydrogenase gene.

Applied Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Boer H, Maaheimo H, Koivula A, Penttilä M, Richard P There are at least three different pathways for the catabolism of D: -galacturonate in microorganisms. In the oxidative pathway, which was described in some prokaryotic species, D: -galacturonate is first oxidised to meso-galactarate (mucate) by a nicotinamide adenine dinucleotide (NAD)-dependent dehydrogenase (EC 1.1.1.203). In the following steps of the pathway mucate is converted to 2-keto-glutarate. The enzyme activities of this catabolic pathway have been described while the corresponding gene sequences are still unidentified. The D: -galacturonate dehydrogenase was purified from Agrobacterium tumefaciens, and the mass of its tryptic peptides was determined using MALDI-TOF mass spectrometry. This enabled the identi...

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An L-arabinose isomerase from Acidothermus cellulolytics ATCC 43068: cloning, expression, purification, and characterization.

Applied Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Cheng L, Mu W, Zhang T, Jiang B The araA gene encoding an L-arabinose isomerase (L-AI) from the acido-thermophilic bacterium Acidothermus cellulolytics ATCC 43068 was cloned and overexpressed in Escherichia coli. The open reading frame of the L-AI consisted of 1,503 nucleotides encoding 501 amino acid residues. The recombinant L-AI was purified to homogeneity by heat treatment, ion-exchange chromatography, and gel filtration. The molecular mass of the enzyme was estimated to be approximately 55 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme was optimally active at 75 degrees C and pH 7.5. It required divalent metal ions, either Mn(2+) or Co(2+), for both enzymatic activity and thermostability improvement at higher temperatures. The enzyme...

Microbial conversion of ruscogenin by Gliocladium deliquescens NRRL1086: glycosylation at C-1.

Applied Microbiology and Biotechnology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Chen ND, Zhang J, Liu JH, Yu BY The glycosylation of ruscogenin (1) by Gliocladium deliquescens NRRL 1086 was observed and gave a regioselectively glycosylated product identified as ruscogenin 1-O-beta-D-glucopyranoside (2) by infrared, mass spectrometry, and nuclear magnetic resonance spectra. Time-course studies indicated that it appeared to be favorable to accumulate 2 when ruscogenin was added to the 24-h-old stage II culture, and the yield of 2 was about 20.1% during 120 approximately 168 h. It was noted that additional carbohydrates could significantly increase glycoside formation and the yield of 2 even reached as high as 68% compared with the control 20.1%. The primary investigation about the characteristics of the enzyme resulted that the reaction was blocked by beta-...

In Vitro Synergistic Activities of Essential Oils and Surfactants in Combination with Cosmetic Preservatives Against Pseudomonas aeruginosa and Staphylococcus aureus.

Current Microbiology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Patrone V, Campana R, Vittoria E, Baffone W The aim of this study is to evaluate possible synergistic antimicrobial interactions between common cosmetic preservatives and selected essential oils or surfactants. The antimicrobial efficacy of six essential oils, three surfactants and five preservatives against Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 43387 was assessed by a broth micro-dilution assay. MICs for individual and combined antimicrobials were determined and then transformed to fractional inhibitory concentration (FIC) indexes. All essential oils exhibited antibacterial activity; among surfactants, bacteria resulted most susceptible to the cationic agent. Synergy was observed when essential oils of eucalyptus and mint were combined with methylpar...

Proteomic Analysis of the Effect of Cyanide on Klebsiella oxytoca.

Current Microbiology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Tang P, Hseu YC, Chou HH, Huang KY, Chen SC Cyanide has been proved to be degraded by Klebsiella oxytoca. In order to examine the physiological responses of cyanide degradation by this bacterium, two-dimensional (2-DE) electrophoresis approach and MALDI-TOF-MS allow us to identify 106 proteins spots that were significantly altered in the presence of 1 mM cyanide in relative to that in 1 mM ammonia when K. oxytoca grown at the late-log phase. Among them, 27 proteins were successfully identified. These proteins were involved in carbohydrate metabolism, nucleotide metabolism, amino acid metabolism, nitrogen metabolism, stress responses, oxidation-reduction reactions, transporters, and miscellaneous function. Some proteins related with regulation of nitrogen assimilation pathways ...

Novel Integron Gene Cassette Arrays Identified in a Global Collection of Multi-Drug Resistant Non-Typhoidal Salmonella enterica.

Current Microbiology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Krauland M, Harrison L, Paterson D, Marsh J Investigation of integron carriage in a global collection of multi-drug resistant Salmonella enterica identified 3 unique class 1 integron gene cassette arrays not previously reported in this species. The present study used PCR and DNA sequence analysis to characterize the structure of these gene cassette arrays. A ~4.0 kb integron containing the gene cassette array arr2/cmlA5/bla (OXA10) /aadA1 was found in isolates belonging to serovars Isangi and Typhimurium from South Africa. A ~6.0 kb integron containing the gene cassettes aac(6')IIc/ereA2/IS1247/aac/arr/ereA2 was found in isolates belonging to serovar Heidelberg from the Philippines. In this gene cassette array, the insertion sequence, IS1247, and two putative resistance genes,...

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The pheV Phenylalanine tRNA Gene in Klebsiella pneumoniae Clinical Isolates Is an Integration Hotspot for Possible Niche-Adaptation Genomic Islands.

Current Microbiology — Tue, 17 Nov 2009 00:00:00 +0100

Authors: Chen N, Ou HY, van Aartsen JJ, Jiang X, Li M, Yang Z, Wei Q, Chen X, He X, Deng Z, Rajakumar K, Lu Y Horizontally acquired genomic islands may allow bacteria to conquer and colonize previously uncharted niches. Four Klebsiella pneumoniae tRNA gene insertion hotspots (arg6, asn34, met56, and pheV) in 101 clinical isolates derived from blood, sputum, wound, bile or urine specimens were screened by long-range PCR for the presence or absence of integrated islands. The pheV phenylalanine tRNA gene was the most frequently occupied site and harbored at least three entirely distinct types of islands: (1) KpGI-1, a 3.7 kb island coding for four proteins, three of which showed high similarity to two hypothetical proteins and a Gcn5-related N-acetyltransferase in Salmonella enterica, (2)...

Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

Parasites and Vectors — Tue, 17 Nov 2009 00:00:00 +0100

Conclusions: This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies. (Source: Parasites and Vectors)

Interaction between phosphorus and biodegradable organic carbon on drinking water biofilm subject to chlorination

Journal of Applied Microbiology — Tue, 17 Nov 2009 00:00:00 +0100

Conclusions: Biodegradable organic carbon was found to be the primary nutrient in regulating biofilm formation in drinking water regardless of the presence of chlorine. It can be therefore concluded that the removal of an easily biodegradable organic carbon is necessary to minimize the biofilm growth potential induced by the intrusion of phosphorus.Significance and Impact of the Study: Phosphorus introduced to drinking water may interact with biodegradable organic carbon, thus leading to measurable impact on the biofilm formation. (Source: Journal of Applied Microbiology)

Conjugative DNA metabolism in Gram-negative bacteria

FEMS Microbiology Reviews — Tue, 17 Nov 2009 00:00:00 +0100

Bacterial conjugation in Gram-negative bacteria is triggered by a signal that connects the relaxosome to the coupling protein (T4CP) and transferosome, a type IV secretion system. The relaxosome, a nucleoprotein complex formed at the origin of transfer (oriT), consists of a relaxase, directed to the nic site by auxiliary DNA-binding proteins. The nic site undergoes cleavage and religation during vegetative growth, but this is converted to a cleavage and unwinding reaction when a competent mating pair has formed. Here, we review the biochemistry of relaxosomes and ponder some of the remaining questions about the nature of the signal that begins the process. (Source: FEMS Microbiology Reviews)

Global Reemergence of Tuberculosis: Are Host Defense Peptides an Option to Ameliorate Disease Burden?

Microbial Drug Resistance — Mon, 16 Nov 2009 18:01:14 +0100

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

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Effect of New Breakpoints Proposed by Clinical and Laboratory Standards Institute in 2008 for Evaluating Penicillin Resistance of Streptococcus pneumoniae in a Turkish University Hospital

Microbial Drug Resistance — Mon, 16 Nov 2009 17:38:50 +0100

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

Development of a DNA Microarray to Detect Antimicrobial Resistance Genes Identified in the National Center for Biotechnology Information Database

Microbial Drug Resistance — Mon, 16 Nov 2009 17:38:25 +0100

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

Host response: Spotlight on SFB

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 840 (2009). doi:10.1038/nrmicro2277 Author: Katrina Ray The human gut is home to trillions of commensal microorganisms, and we are beginning to understand how these microorganisms interact with, and influence, the host immune system. New research published in Immunity and Cell now reveals that a specific commensal species, segmented filamentous (Source: Nature Reviews Microbiology)

Fungal metabolism: Completing the circle

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 842 (2009). doi:10.1038/nrmicro2276 Author: Sheilagh Molloy Fungi can produce an impressive variety of secondary metabolites, the most abundant of which are the polyketides. Reporting in Nature, Jason Crawford, Tyler Korman and colleagues present the mechanistic basis of the main cyclization reaction that is necessary for the production of the potent (Source: Nature Reviews Microbiology)

In Brief

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 841 (2009). doi:10.1038/nrmicro2275 BiofilmsEscherichia coli (Source: Nature Reviews Microbiology)

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In this issue

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 837 (2009). doi:10.1038/nrmicro2274 The WHO estimates that a third of the world's population is infected with Mycobacterium tuberculosis, even if they do not show signs of clinical disease. However, the classification of tuberculosis (TB) as either latent or active has limited our understanding of its biology. On (Source: Nature Reviews Microbiology)

Closing the GAPP on pneumonia

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 838 (2009). doi:10.1038/nrmicro2273 Pneumonia kills more children under 5 years of age than any other infectious disease, but affordable and effective treatment and prevention measures are available. The time has come for the world to wake up to this forgotten killer. (Source: Nature Reviews Microbiology)

Disease watch: In the news

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 844 (2009). doi:10.1038/nrmicro2272 Paracetamol reduces vaccine effectivenessRoutinely giving paracetamol to children after vaccination as a precaution against fever may reduce the effectiveness of the vaccination itself, researchers from the Czech Republic have found. A randomized trial of 459 children receiving vaccines showed that treatment with paracetamol in (Source: Nature Reviews Microbiology)

Genome watch: Probiotics stick it to the man

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 843 (2009). doi:10.1038/nrmicro2271 Author: Alan Walker This month's Genome Watch highlights the part that genomics can play in generating new insights into the interactions of probiotic Lactobacillus strains with the human gut. (Source: Nature Reviews Microbiology)

Bacterial physiology: Switch-hitting RNase

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 842 (2009). doi:10.1038/nrmicro2267 Author: Andrew Jermy In the Gram-negative bacterium Escherichia coli, mRNA decay is initiated by RNase E-mediated endonucleolytic cleavage. By contrast, Gram-positive Bacillus subtilis lacks RNase E but does contain two enzymes, RNase J1 and RNase J2, that have endonucleolytic and 5′–3′ exonucleolytic activity and are known (Source: Nature Reviews Microbiology)

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No link between probiotics and obesity? Author reply

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Nature Reviews Microbiology 7, 901 (2009). doi:10.1038/nrmicro2209-c3 Author: Didier Raoult I am surprised that my Editorial (Probiotics and obesity: a link? (Source: Nature Reviews Microbiology)

No causal link between obesity and probiotics

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Authors: Nathalie Delzenne & Gregor Reid We wish to counter the comments of Raoult (Probiotics and obesity: a link? (Source: Nature Reviews Microbiology)

Probiotics – little evidence for a link to obesity

Nature Reviews Microbiology — Mon, 16 Nov 2009 16:26:32 +0100

Probiotics – little evidence for a link to obesity Nature Reviews Microbiology 7, 901 (2009). doi:10.1038/nrmicro2209-c1 Author: S. Dusko Ehrlich In a recent Editorial by Raoult (Probiotics and obesity: a link? (Source: Nature Reviews Microbiology)

Prion Protein

Microbiology Blog: The weblog for microbiologists. — Mon, 16 Nov 2009 14:48:00 +0100

A conformational transition of the cellular prion protein (PrPC) into an aberrantly folded isoform designated scrapie prion protein (PrPSc) is the hallmark of a variety of neurodegenerative disorders collectively called prion diseases. They include Creutzfeldt-Jakob disease and Gerstmann-Stäussler-Scheinker syndrome in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle and chronic wasting disease (CWD) in free-ranging deer. In contrast to the deadly properties of misfolded PrP, PrPC seems to possess a neuroprotective activity. More-over, animal models indicated that the stress-protective activity of PrPC and the neurotoxic effects of PrPSc are somehow interconnectedfrom The Prion ProteinFurther reading:The Prion ProteinFull range of books on microbiology at Mic...

Gene cloning, characterization, and heterologous expression of levansucrase from Bacillus amyloliquefaciens.

Journal of Industrial Microbiology and Biotechnology — Mon, 16 Nov 2009 00:00:00 +0100

In this study, we cloned and characterized the enzymatic kinetics using levansucrase expressed in Escherichia coli. Optimum pH for D: -glucose production and levan formation was 6.0 and 8.0, respectively, whereas optimum temperature was 30 degrees C and 4 degrees C, respectively. The K (m) and V (max) values for levansucrase were calculated to be 47.81 mM sucrose and 57.47 mumole/min mg protein, respectively. Prominent expression of levansucrase was obtained through xylose induction in Bacillus megaterium, where most of the His(6)-tagged protein was secreted into the culture broth, giving levansucrase activity of 12,906 U/l. Response-surface methodology (RSM) was further employed to optimize the fermentation conditions and improve the level of levansucrase production. Maximum levansucrase ...

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A new xylanase from thermoacidophilic Alicyclobacillus sp. A4 with broad-range pH activity and pH stability.

Journal of Industrial Microbiology and Biotechnology — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Bai Y, Wang J, Zhang Z, Yang P, Shi P, Luo H, Meng K, Huang H, Yao B We have identified a highly pH-adaptable and stable xylanase (XynA4) from the thermoacidophilic Alicyclobacillus sp. A4, a strain that was isolated from a hot spring in Yunnan Province, China. The gene (xynA4) that encodes this xylanase was cloned, sequenced, and expressed in Escherichia coli. It encodes a 338-residue polypeptide with a calculated molecular mass of 42.5 kDa. The deduced amino acid sequence is most similar to (53% identity) an endo-1,4-beta-xylanase from Geobacillus stearothermophilus that belongs to family 10 of the glycoside hydrolases. Purified recombinant XynA4 exhibited maximum activity at 55 degrees C and pH 7.0, had broad pH adaptability (>40% activity at pH 3.8-9.4) and stability (r...

Novel insights about class 2 integrons from experimental and genomic epidemiology.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Ramírez MS, Piñeiro S, , Centrón D In order to contribute to the knowledge of the architecture and epidemiology of class 2 integrons, we performed a class 2 integron molecular survey analyzing 726 isolates in two bacterial populations, from environmental and non-epidemiologically related clinical samples, respectively, collected during 1982-2007. We recovered the intI2 gene in 130 out of 726 isolates, of which most were clinical isolates, and only one (a psychrophilic Pseudomonas spp.) was from a water sample. Unlike the widespread distribution of class 1 integrons within gram-negative bacilli, only Acinetobacter baumannii and Enterobacter cloacae harbored class 2 integrons with high frequency in our collection. Class 2 integrons with 6 novel cassette arrays wer...

Ceftobiprole is Superior to Vancomycin, Daptomycin, and Linezolid, for the Treatment of Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis in Rabbits.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Tattevin P, Basuino L, Bauer D, Diep BA, Chambers HF Beta lactam agents are the most active drugs for the treatment of streptococci and methicillin-susceptible Staphylococcus aureus endocarditis. However, methicillin-resistant S. aureus (MRSA) are resistant to all beta lactam agents licensed to date, and alternative treatments are limited. Ceftobiprole is a novel broad-spectrum cephalosporin that binds with high affinity to PBP 2a, the penicillin-binding protein that mediates methicillin resistance of staphylococci, and is active against MRSA. Ceftobiprole was compared to vancomycin, daptomycin, and linezolid, in a rabbit model of MRSA aortic valve endocarditis caused by the homogenously methicillin-resistant laboratory strain, COL. Residual organisms in vegetations were signi...

Panel of Prototypical Raltegravir-Resistant Infectious Molecular Clones in a Novel Integrase-Deleted Cloning Vector.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Reuman EC, Bachmann MH, Varghese V, Fessel WJ, Shafer RW We created an HIV-1 cloning vector, pNL4.3DeltaIN, to generate recombinant infectious molecular clones for analysis of patient-derived HIV-1 integrase coding regionsgenes. Using this vector, we constructed a clinically-derived virus panel clinical integrase genes with the canonical patterns of raltegravir-resistance mutations and submitted the panel to the NIH AIDS Research and Reference Reagent Program. Investigational integrase inhibitors with activity against these clones are likely to retain activity against the most clinically relevant raltegravir-resistant variants. PMID: 19917747 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Anti-Clostridium difficile Potential of Tetramic Acid Derivatives from Pseudomonas Quorum-Sensing Autoinducer.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Ueda C, Tateda K, Horikawa M, Kimura S, Ishii Y, Nomura K, Yamada K, Suematsu T, Inoue Y, Ishiguro M, Miyairi S, Yamaguchi K We have examined the potential bactericidal activity of several tetramic acids derived from Pseudomonas autoinducers, against Clostridium difficile, a cause of antibiotic-associated pseudomembrane colitis. Clinical isolates of C. difficile (n=4) were incubated in broth with a chemically synthesized Pseudomonas autoinducer and its tetramic acid derivatives. The structure-activity correlation and the mechanisms of action were examined by a time-killing assay and morphological/staining characteristics. Some tetramic acids derived from 3-oxo-C12 homoserine lactone resulted in more than 3 log reduction of viability of C. difficile within 30 min at 30 muM. The...

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Interaction of ceftobiprole with the Enterococcus faecium low-affinity PBP5.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Henry X, Amoroso A, Coyette J, Joris B Ceftobiprole is a new cephalosporin that exhibits a high affinity for the methicillin-resistant Staphylococcus aureus PBP2a. It was reported that ceftobiprole did not interact with a mutated form of the low-affinity Enterococcus faecium PBP5 (PBBP5fm) that when over-expressed confers a beta-lactam resistance phenotype to the bacterium. Our results show that ceftobiprole binds to the unmutated PBP5fm to form a stable acyl-enzyme and that it is able to efficiently kill a penicillin-resistant Enterococcus faecium strain that has this protein. PMID: 19917749 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

VIM-19, a metallo-ss-lactamase with increased carbapenemase activity from Escherichia coli and Klebsiella pneumoniae.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

This study indicates that MBLs with an enhanced activity toward carbapenems may be obtained as a result of very few amino acid substitutions. PMID: 19917750 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Efficacy of Posaconazole against three clinical Aspergillus fumigatus Isolates with Mutations in the cyp51A Gene.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Mavridou E, Brüggemann RJ, Melchers WJ, Mouton JW, Verweij PE The in-vivo efficacy of posaconazole against 4 clinical Aspergillus fumigatus isolates with posaconazole MICs ranging from 0.03 to 16 mg/L, as determined with the CLSI-M38A method, was assessed in a nonneutropenic murine model of disseminated aspergillosis. Underlying resistance mechanisms of the isolates included substitutions in the cyp51A gene at codon 220 (M220I), codon 54 (G54W) and codon 98 (L98H). The latter was combined with a 34 bp tandem repeat in the gene promoter region (TR/L98H). The control isolate exhibited a wild type phenotype without any known resistance mechanism. Oral posaconazole therapy was started 24 h after infection once daily for 14 consecutive days. Mice were treated with four differe...

Fitness Costs and Stability of a High-Level Ciprofloxacin Resistance Phenotype in Salmonella enterica Serotype Enteritidis: Reduced Infectivity Associated with Decreased Expression of SPI-1 Genes.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

In conclusion, high-level ciprofloxacin resistance in Salmonella Enteritidis is associated with fitness costs. In the absence of antibiotic selection pressure isolates may acquire mutations enabling reversion to an intermediate-level ciprofloxacin resistance phenotype associated with less significant fitness costs. PMID: 19917752 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Gallium disrupts iron uptake by intracellular and extracellular francisella and exhibits therapeutic efficacy in a murine pulmonary infection model.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

GALLIUM DISRUPTS IRON UPTAKE BY INTRACELLULAR AND EXTRACELLULAR FRANCISELLA AND EXHIBITS THERAPEUTIC EFFICACY IN A MURINE PULMONARY INFECTION MODEL. Antimicrob Agents Chemother. 2009 Nov 16; Authors: Olakanmi O, Gunn JS, Su S, Soni S, Hassett DJ, Britigan BE Francisella tularensis requires iron (Fe) for growth, but the biologic sources of Fe for this organism are largely unknown. We found that Francisella sp. growing in broth culture or within human macrophages can acquire Fe from the two major host Fe binding proteins, lactoferrin (Lf) and transferrin (Tf). Fe acquisition is a potential target for novel therapies. Gallium (Ga) is a transition metal that interferes with cellular Fe metabolism by competing with Fe for uptake/utilization. Growth of either F. tularensis LVS (LVS) ...

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Mutasynthesis of lincomycin derivatives with activity against drug-resistant staphylococci.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Ulanova D, Novotná J, Smutná Y, Kameník Z, Gazak R, Sulc M, Sedmera P, Kadlcik S, Plhackova K, Janata J The lincomycin biosynthetic gene lmbX was deleted in Streptomyces lincolnensis ATCC 25466 that led to abolition of lincomycin production. Complementation experiments proved the blockage in biosynthesis of lincomycin precursor 4-propyl-L-proline. Feeding this mutant strain with precursor derivatives resulted in production of 4'-butyl-4'-depropyllincomycin and 4'-pentyl-4'-depropyllincomycin in high titers and without lincomycin contamination. Moreover, 4'-pentyl-4'-depropyllincomycin was found to be more active than lincomycin against clinical Staphylococcus isolates with genes determining low-level lincosamide resistance. PMID: 19917754 [PubMed - as suppli...

Characteristics and population dynamics of mosaic penA allele-containing Neisseria gonorrhoeae isolated in Sydney, Australia, 2007 - 2008.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Tapsall JW, Ray S, Limnios A 1800 Neisseria gonorrhoeae isolated in Sydney, Australia in 2007-2008 were examined for mosaic penA that mediated cephalosporin resistance and for their genotype. In 2008, there were substantial increases in numbers (15 to 85) and proportions (1.5% to 10.3%) of mosaic-containing gonococci and major shifts in genotypic patterns when ten new genotypes represented 74 of the 85 mosaic-containing isolates and genotypes detected between 2001 and 2005 disappeared. Enhanced surveillance of gonococcal resistance to cephalosporins is necessary. PMID: 19917755 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Efficacy profile of daptomycin for the treatment of invasive as compared to non-invasive pulmonary infections with S. pneumoniae.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Henken S, Bohling J, Martens-Lobenhoffer J, Paton JC, Ogunniyi AD, Briles DE, Salisbury VC, Wedekind D, Bode-Böger SM, Welsh T, Bange F, Welte T, Maus UA Daptomycin is a novel lipopeptide antibiotic with excellent activity against Gram-positive bacterial pathogens, but its therapeutic value for the treatment of invasive pneumococcal disease as compared to pneumococcal pneumonia is incompletely defined. We investigated the efficacy of daptomycin in two models of S. pneumoniae-induced lung infection, i.e., pneumococcal pneumonia or septic pneumococcal disease. Mice were infected with bioluminescent, invasive serotype 2 or less virulent serotype 19 S. pneumoniae, followed by semi-therapeutic or therapeutic daptomycin or ceftriaxone treatment. Readouts included survival, bact...

In Vitro and In Vivo Efficacy of Teicoplanin-loaded Calcium Sulphate for the Treatment of Chronic MRSA Osteomyelitis.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Jia WT, Luo SH, Zhang CQ, Wang JQ In vitro and in vivo therapeutic efficacy of teicoplanin-loaded calcium sulphate (TCS, 10 wt% teicoplanin) was investigated in a rabbit model of chronic methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis. The in vitro elution characteristics of teicoplanin from TCS pellets were realized by carrying out an evaluation on release kinetics, recovery rate and antibacterial activity of the released teicoplanin. Chronic osteomyelitis was induced by inoculating 10(7) cfu of MRSA strain into the tibial cavity of rabbits. After 3 weeks, the animals were treated by debridement, followed by implantation of TCS pellets in Group 1, calcium sulphate (CS) pellets alone in Group 2, and intravenous (iv) teicoplanin (6 mg/kg every 12 h for three do...

Generic and specific adaptative response of Streptococcus pneumoniae to challenge with three distinct antimicrobial peptides: bacitracin, LL-37 and nisin.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

In conclusion, we show that resistance to three different AMPs in S. pneumoniae is mediated by several putative ABC transporters, some of which have not been associated with antimicrobial resistance in this organism before. In addition, a GntR-like regulator was identified, which regulates two of these transporters. Our findings extend the understanding of defense mechanisms of this important human pathogen against antimicrobial compounds and points toward novel proteins, i.e. putative ABC transporters, which can be used as targets for the development of new antimicrobials. PMID: 19917758 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

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Escherichia coli Sequence Type ST131 as an Emerging Fluoroquinolone-Resistant Uropathogen among Renal Transplant Recipients.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Johnson JR, Johnston B, Clabots C, Kuskowski MA, Pendyala S, Debroy C, Nowicki B, Rice J Among 40 Escherichia coli urine isolates from renal transplant recipients (Galveston, Texas: 2003-2005), sequence type ST131 (O25:H4) was highly prevalent (35% overall; 60% of fluoroquinolone-resistant isolates), virulent-appearing, antimicrobial resistant (but extended-spectrum-cephalosporin-susceptible), and associated with black race. Pulsotypes were diverse; some linked to other locales. ST131 emerged significantly during the study period. These findings suggest that E. coli ST131 may constitute an important new multidrug-resistant threat to renal transplant recipients. PMID: 19917759 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Cellular Pharmacology of the Anti-Hepatitis B Virus Agent ss-L-2',3'-Didehydro-2',3'-dideoxy-N4-hydroxycytidine: Relevance for the Activation in HepG2 Cells.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

Authors: Matthes E, Bünger H ss-L-2',3'-didehydro-2',3'-dideoxy-N(4)-hydroxycytidine (L-Hyd4C) was demonstrated to be an effective and highly selective inhibitor of hepatitis B virus (HBV) replication in HepG2.2.15 cells (ED50=0.03 muM; CD50 =2,500 muM). In the present study we investigated the intracellular pharmacology of tritiated L-Hyd4C in HepG2 cells. [(3)H]L-Hyd4C was shown to be phospho-rylated extensively and rapidly to the 5'-mono-, 5'-di- and 5'-triphosphate derivatives. Other metabolites deriving from a reduction or removal of the NHOH-group of L-Hyd4C could not be detected, although both reactions were described as the primary catabolic pathways of the stereoisomer ss-D-N(4)-hydroxycytidine in HepG2 cells. Also the formation of liponucleotide metabolites such as the 5...

Structure-microbicidal activity relationship of synthetic fragments derived from the antibacterial {alpha}-helix of human lactoferrin.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

In this study the structure - microbicidal activity relationship of amino acid residues 14-31 from the N-terminal end, corresponding to the antibacterial alpha-helix of human lactoferrin (LF), was investigated by down-sizing, alanine scanning and substitution of amino acids. Microbicidal analysis (99 % killing) was performed by a microplate assay, using E. coli, S. aureus, and C. albicans as test organisms. Starting from the N-terminal end, downsizing of peptide sequence 14-31 showed that the peptide 19-31 (KCFQWQRNMRKVR, HL9) was the optimal length for antimicrobial activity. Furthermore, HL9 bound to lipid A/LPS, as shown by neutralising endotoxic activity in a Limulus assay. Alanine-scanning of peptide sequence 20-31 showed that Cys-20, Trp-23, Arg-28, Lys-29 or Arg-31 were important fo...

In Vitro Potency of CXA-101, a Novel Cephalosporin, Against Resistant Phenotypes of Pseudomonas aeruginosa, Including Multi-drug Resistant Isolates.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

We describe the activity of a novel cephalosporin, CXA-101 (FR26 4205) against a panel of highly resistant Pseudomonas aeruginosa isolates collected from US hospitals. CXA-101 demonstrated increased potency against this population of resistant isolates, with activity 4- to 10-fold higher than that of comparator agents in each phenotypic category. The addition of tazobactam did not improve its activity. CXA-101 appears to be a promising addition to the category of anti-pseudomonal beta-lactams. PMID: 19917762 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

Method for screening compounds that influence virulence gene expression in Staphylococcus aureus.

Antimicrobial Agents and Chemotherapy — Mon, 16 Nov 2009 00:00:00 +0100

We present a simple assay to examine effects of compounds on virulence gene expression in the human pathogen, Staphylococcus aureus. The assay employs transcriptional reporter strains carrying lacZ fused to central virulence genes. Compounds affecting virulence gene expression and activity of the agr locus are scored as colour change in presence of a chromogenic beta-galactosidase substrate. The assay can be used to screen for novel anti-virulence compounds from many different sources such as fungi as demonstrated here. PMID: 19917763 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

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Preliminary study on temporal variations in biting activity of Simulium damnosum s.l. in Abeokuta North LGA, Ogun State Nigeria

Parasites and Vectors — Mon, 16 Nov 2009 00:00:00 +0100

Conclusion: The results from this study showed that both the forest and the savannah dwelling groups of S. damnosum s.l. were caught biting in the study area. This could have implications on the transmission and epidemiology of human onchocerciasis if not monitored. (Source: Parasites and Vectors)

Bacteria colonizing root nodules of wild legumes exhibit virulence-associated properties of mammalian pathogens.

Antonie van Leeuwenhoek — Sun, 15 Nov 2009 00:00:00 +0100

Authors: Muresu R, Maddau G, Delogu G, Cappuccinelli P, Squartini A Bacteria not proficient in nitrogen fixing symbiosis were proven able to invade root nodules of three wild legumes of the genus Hedysarum in Algeria and to be multiplying in these in place of the natural rhizobium symbionts. The involved species featured taxa known as human pathogens including: Enterobacter cloacae, Enterobacter kobei, Escherichia vulneris, Pantoea agglomerans and Leclercia adecarboxylata. A direct screening of the phenotypic determinants of virulence using human cultured cells tested positive for the traits of cytotoxicity, vital stain exclusion and adhesion to epithelia. Antibiogram analyses revealed also a complex pattern of multiple antibiotic resistances. The data suggest that legume root nodules ...

Clinical characteristics and outcomes of patients with vancomycin-susceptible Enterococcus faecalis and Enterococcus faecium bacteraemia—a five-year retrospective review

European Journal of Clinical Microbiology & Infectious Diseases — Sat, 14 Nov 2009 20:38:53 +0100

Abstract The purpose of this study was to assess the epidemiology and outcomes of enterococcal bacteraemia. A retrospective review of demographic, microbiological and clinical data in patients 16 years of age and over with Enterococcus faecalis or E. faecium bacteraemia at Auckland City Hospital, New Zealand, from June 2002 to May 2007 was carried out. A total of 212 patients fulfilled the inclusion criteria, with 205 being included in the analysis. E. faecalis accounted for 86% (176/205) and E. faecium 14% (29/205) of the patients. Amoxycillin resistance occurred in 69% (20/29) of E. faecium isolates. High-level gentamicin resistance was present in 38% (65/171) of E. faecalis isolates and 25% (7/28) of E. faecium isolates (P = NS). No vancomycin-resistant enterococci...

Characterization of modification enzyme NukM and engineering of a novel thioether bridge in lantibiotic nukacin ISK-1.

Applied Microbiology and Biotechnology — Sat, 14 Nov 2009 00:00:00 +0100

Authors: Shioya K, Harada Y, Nagao JI, Nakayama J, Sonomoto K The lantibiotic nukacin ISK-1 is an antimicrobial peptide containing unusual amino acids such as lanthionine and dehydrobutyrine. The nukacin ISK-1 prepeptide (NukA) undergoes posttranslational modifications, such as the dehydration and cyclization reactions required to form the unusual amino acids by the modification enzyme NukM. We have previously constructed a system for the introduction of unusual amino acids into NukA by coexpression of NukM in Escherichia coli. Using this system, we describe the substrate specificity of NukM by the coexpression of a series of NukA mutants. Our results revealed the following characteristics of NukM: (1) its dehydration activity is not coupled to its cyclization activity; (2) its dehydra...

Light regulation of metabolic pathways in fungi.

Applied Microbiology and Biotechnology — Sat, 14 Nov 2009 00:00:00 +0100

Authors: Tisch D, Schmoll M Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and...

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Nitrification in fixed-bed reactors treating saline wastewater.

Applied Microbiology and Biotechnology — Sat, 14 Nov 2009 00:00:00 +0100

Authors: Sudarno U, Bathe S, Winter J, Gallert C Halophilic nitrifiers belonging to the genus Nitrosomonas and Nitrospira were enriched from seawater and marine sediment samples of the North Sea. The maximal ammonia oxidation rate (AOR) in batch enrichments with seawater was 15.1 mg N L(-1) day(-1). An intermediate nitrite accumulation was observed. Two fixed-bed reactors for continuous nitrification with either polyethylene/clay sinter lamellas (FBR A) or porous ceramic rings (FBR B) were run at two different ammonia concentrations, three different ammonia loading rates (ALRs), +/- pH adjustment, and at an increased upflow velocity. A better overall nitrification without nitrite accumulation was observed in FBR B. However, FBR A revealed a higher AOR and nitrite oxidation rate of 6 an...

Personalized management of patients with inoperable alveolar echinococcosis undergoing treatment with albendazole: usefulness of positron-emission-tomography combined with serological and computed tomography follow-up

Clinical Microbiology and Infection — Sat, 14 Nov 2009 00:00:00 +0100

Clin Microbiol Infect The present study aimed to identify a sub-group of inoperable alveolar echinococcosis (AE) patients undergoing long-term treatment with benzimidazole (BZM) who presented with an evolution suggestive of a parasitocidal effect. An evolution compatible with parasite death was observed in five patients. (Source: Clinical Microbiology and Infection)

Molecular cloning and transcriptional analysis of a newly identified anti-lipopolysaccharide factor gene in kuruma shrimp, Marsupenaeus japonicus

Letters in Applied Microbiology — Sat, 14 Nov 2009 00:00:00 +0100

Conclusions: The present work revealed the presence of MjALF2 gene, which is highly expressed in gills and muscle of healthy kuruma shrimp. Further studies are required to clarify the involvement of MjALF2 in immune responses for using as a therapeutic agent.Significance and Impact of the Study: Antimicrobial peptides are promising potential therapeutic agents for disease control in aquaculture. Understanding the relation of MjALF2 with innate immunity mechanism will lead to develop better health management strategies for long-term sustainability of the shrimp industry. (Source: Letters in Applied Microbiology)

Expression of the yeast aquaporin Aqy2 affects cell surface properties under the control of osmoregulatory and morphogenic signalling pathways

Molecular Microbiology — Sat, 14 Nov 2009 00:00:00 +0100

Aquaporins mediate rapid and selective water transport across biological membranes. The yeast Saccharomyces cerevisiae possesses two aquaporins, Aqy1 and Aqy2. Here, we show that Aqy2 is involved in controlling cell surface properties and that its expression is controlled by osmoregulatory and morphogenic signalling pathways. Deletion of AQY2 results in diminished fluffy colony morphology while overexpression of AQY2 causes strong agar invasion and adherence to plastic surfaces. Hyper-osmotic stress inhibits morphological developments including the above characteristics as well as AQY2 expression through the osmoregulatory Hog1 mitogen-activated protein kinase. Moreover, two pathways known to control morphological developments are involved in regulation of AQY2 expression: the protein kina...

Fosfomycin: an old, new friend?

European Journal of Clinical Microbiology & Infectious Diseases — Fri, 13 Nov 2009 18:22:53 +0100

Abstract Fosfomycin (FOM) is an antibiotic which has varying application indications across the globe. European, Japanese, South African and Brazilian usage practices are much broader, involving multiple formulations of FOM than the currently limited application of FOM in the United States, where uncomplicated urinary tract infection represents the only indication for FOM-tromethamine. Based on early difficulty in determining FOMs genuine in vitro activity, there was initial skepticism about its efficacy and application range. However, in the mid 1970s, correctly executed experiments coupled with an improved understanding of microbiological concepts opened the door for broader use of FOM. During the following 40 years FOM was evaluated in pre-clinical and clinical tri...

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Erratum to “Phenotypic and genotypic characterization of drug-resistant Mycobacterium tuberculosis strains” [Diagn Microbiol Infect Dis 62 (2008) 199–204]

Diagnostic Microbiology and Infectious Disease — Fri, 13 Nov 2009 16:17:00 +0100

After publication of the above mentioned article, a revised was provided and is included below. Furthermore, on page 203 under Section 4.3 Pyrazinamide, the sentence reading “Our study observed that around 60% of PZA-resistant strains had pncA gene mutations from positions 136 to 188, and although pncA is a small gene, mutations in various positions of its structure have been found (Zhang and Mitchinson, 2003).”, should read, “Our study observed that around 60% of PZA-resistant strains had pncA gene mutations from positions 99 to 175, and although pncA is a small gene, mutations in various positions of its structure have been found (Zhang and Mitchinson, 2003).” (Source: Diagnostic Microbiology and Infectious Disease)

Zyvox® Annual Appraisal of Potency and Spectrum program: linezolid surveillance program results for 2008

Diagnostic Microbiology and Infectious Disease — Fri, 13 Nov 2009 16:16:59 +0100

In conclusion, the activity of linezolid remained uniform and stable across the sampled geographic regions studied when compared to the 2006 to 2007 results. Documented LZD-R remains rare (only 0.13% overall but highest for CoNS [0.41%] and enterococci [0.69%]) among the 24 countries sampled for the 6 different pathogen groups. Rates of clindamycin resistance and the frequency of MRSA varied by geographic region and between nations; therefore, like oxazolidinones, it requires continued surveillance for changing resistance patterns. (Source: Diagnostic Microbiology and Infectious Disease)

Linezolid surveillance program results for 2008 (LEADER Program for 2008)

Diagnostic Microbiology and Infectious Disease — Fri, 13 Nov 2009 16:16:59 +0100

In conclusion, linezolid activity sampled by the 5th year of this LEADER Program showed sustained potency and spectrum (99.64% susceptibility levels). The nonsusceptible strain isolation rates remained stable and the plasmid-mediated ribosomal-based resistance mechanism that emerged in Staphylococcus aureus and Staphylococcus epidermidis strains in 2007 showed no evidence of dissemination or increased prevalence. However, there was evidence of cfr persistence with the S. epidermidis strain. The LEADER Program continues to be an effective and sensitive surveillance tool to detect and monitor novel oxazolidinone resistance phenotypes and genotypes. (Source: Diagnostic Microbiology and Infectious Disease)

Mycoses in the elderly

European Journal of Clinical Microbiology & Infectious Diseases — Fri, 13 Nov 2009 07:44:36 +0100

Abstract Infections with dermatophytes are more prevalent in the elderly than in non-elderly adults; risk factors include local trophic disturbances, underlying diseases such as diabetes and a reduced oxygen supply due to diminished blood circulation. Vaginal mycoses are seldom found. In systemic yeast infections in patients of advanced age, Candida glabrata plays a relatively important role. The dimorphic fungus Coccidioides immitis is more prevalent in the elderly in endemic areas. Although there is no higher susceptibility to moulds in this age group, there are certain situations increasing the risk. The manifestations and symptoms of infection often differ from those of younger patients, which may hamper diagnosis. Deficits in organ function may influence the antifungal ...

Early candidacy for differentiation into heterocysts in the filamentous cyanobacterium Anabaena sp. PCC 7120.

Archives of Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Toyoshima M, Sasaki NV, Fujiwara M, Ehira S, Ohmori M, Sato N The filamentous cyanobacterium Anabaena sp. PCC 7120 fixes dinitrogen facultatively. Upon depletion of combined nitrogen, about 10% of vegetative cells within the filaments differentiate terminally into nitrogen-fixing cells. The heterocyst has been studied as a model system of prokaryotic cell differentiation, with major focus on signal transduction and pattern formation. The fate of heterocyst differentiation is determined at about the eighth hour of induction (point of no return), well before conspicuous morphological or metabolic changes occur. However, little is known about how the initial heterocysts are selected after the induction by nitrogen deprivation. To address this question, we followed the fate of eve...

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Molecular genetic tools to infer the origin of forest plants and wood.

Applied Microbiology and Biotechnology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Finkeldey R, Leinemann L, Gailing O Most forest tree species exhibit high levels of genetic diversity that can be used to trace the origin of living plants or their products such as timber and processed wood. Recent progress to isolate DNA not only from living tissue but also from wood and wood products offers new opportunities to test the declared origin of material such as seedlings for plantation establishment or timber. However, since most forest tree populations are weakly differentiated, the identification of genetic markers to differentiate among spatially isolated populations is often difficult and time consuming. Two important fields of "forensic" applications are described: Molecular tools are applied to test the declared origin of forest reproductive material used f...

Elimination of glycerol production in anaerobic cultures of Saccharomyces cerevisiae engineered for use of acetic acid as electron acceptor.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

This study provides a proof of principle for the potential of this metabolic engineering strategy to improve ethanol yields, eliminate glycerol production and partially convert acetate, which is a well known inhibitor of yeast performance in lignocellulosic hydrolysates, to ethanol. Further research should address kinetic aspects of acetate reduction and the effect of the elimination of glycerol production on cellular robustness (e.g. osmotolerance). PMID: 19915031 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)

Quantification of cyprinid herpesvirus-3 (CyHV-3) in environmental water using an external standard virus.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Honjo MN, Minamoto T, Matsui K, Uchii K, Yamanaka H, Suzuki AA, Kohmatsu Y, Iida T, Kawabata Z Cyprinid herpesvirus-3 (CyHV-3), a lethal DNA virus that spreads in natural lakes and rivers, infects common carp and koi. We established a quantification method for CyHV-3 that includes a viral concentration method and quantitative PCR combined with an external standard virus. Viral concentration methods were compared using cation-coated filters and ultrafiltration. The recovery of virus-like particles was similar in both methods (cation-coated filter, 44 +/- 19%, n = 3; ultrafiltration, 50 +/- 3%, n = 3); however, the former method was faster and more suitable for routine determinations. The recovery of seeded CyHV-3 based on the cation-coated filter method varied by over three ord...

Identification of the BamVW two-component system involved in transcriptional regulation of aromatic degradation in Geobacter metallireducens.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Juárez JF, Zamarro MT, Barragán MJ, Blázquez B, Boll M, Kuntze K, García JL, Díaz E, Carmona M Regulation of aromatic degradation in obligate anaerobes was studied in the Fe(III)-respiring model organism Geobacter metallireducens GS-15. A two-component system and a sigma(54)-dependent promoter were identified that are both involved in the regulation of the gene coding for benzoate-coenzyme A ligase, catalyzing the initial step of benzoate degradation. PMID: 19915033 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)

Emergence of cell-wall protease in the Streptococcus thermophilus population.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Delorme C, Bartholini C, Bolotine A, Ehrlich SD, Renault P Streptococcus thermophilus is perceived as a recently emerged food bacterium that evolved from a commensal ancestor by loss and gain of functions. Here, we provide data allowing a better understanding of this evolutionary scheme. A MLST approach that we developed showed that S. thermophilus diverges significantly from its potential ancestors of the salivarius group and displays a low allelic variability, confirming its likely recent emergence. An analysis of the origin and dissemination of prtS gene was carried out within this evolutionary scheme. This gene encodes protease that allows a better growth in milk, by facilitating the casein breakdown for amino acid supply. S. thermophilus protease exhibits 95% identity to ...

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Integrated Bioprocessing for the pH-Dependent Production of 4-Valerolactone from Levulinate in Pseudomonas putida KT2440.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Martin CH, Wu D, Prather KL Enzymes are powerful biocatalysts capable of performing specific chemical transformations under mild conditions. Yet as catalysts they remain subject to the laws of thermodynamics, namely that they cannot catalyze chemical reactions beyond equilibrium. Here we report the phenomenon and application of using extracytosolic enzymes and medium conditions such as pH to catalyze metabolic pathways beyond their intracellular catalytic limitations. This methodology, termed "integrated bioprocessing" because it integrates intracellular and extracytosolic catalysis, was applied to a lactonization reaction in Pseudomonas putida for the economical and high-titer biosynthesis of 4-valerolactone from the inexpensive and renewable source levulinic acid. Mutant par...

Nanosized iron oxide colloids strongly enhance microbial iron reduction.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Bosch J, Heister K, Hofmann T, Meckenstock RU Microbial iron reduction is considered to be a significant subsurface process. The rate-limiting bioavailability of the insoluble iron oxyhydroxides, however, is a topic for debate. Surface area and mineral structure are recognized as crucial parameters for microbial reduction rates of bulk, macroaggregate iron minerals. However, a significant fraction of iron oxide minerals in the subsurface is supposed to be present as nanosized colloids. We therefore studied the role of colloidal iron oxides in microbial iron reduction. In batch growth experiments with Geobacter sulfurreducens, colloids of ferrihydrite (hydrodynamic diameter 336 nm), hematite (123 nm), goethite (157 nm), and akaganeite (64 nm) were added as electron acceptors. T...

The Missing Link in LAS Surfactant Degradation: 4-Sulfoacetophenone as a Transient Intermediate in the Degradation of 3-(4-Sulfophenyl)butyrate by Comamonas testosteroni KF-1.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Schleheck D, von Netzer F, Fleischman T, Rentsch D, Huhn T, Cook AM, Kohler HP Biodegradation of the laundry surfactant linear alkylbenzenesulfonate (LAS) involves complex bacterial communities. The known heterotrophic community has two tiers. Firstly, all LAS congeners are oxygenated and oxidized to about 50 sulfophenylcarboxylates (SPC). Secondly, the SPCs are mineralized. Comamonas testosteroni KF-1 mineralizes 3-(4-sulfophenyl)butyrate (3-C4-SPC). During growth of strain KF-1 with 3-C4-SPC, two transient intermediates were detected in the culture medium. One intermediate was identified as 4-sulfoacetophenone (SAP) [4-acetylbenzenesulfonate] by NMR. The other was 4-sulfophenol (SP). This information allowed us to postulate a degradation pathway that comprises the removal of...

A probabilistic model of growth, division, and mortality of microbial cells.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

A PROBABILISTIC MODEL OF GROWTH, DIVISION, AND MORTALITY OF MICROBIAL CELLS. Appl Environ Microbiol. 2009 Nov 13; Authors: Horowitz J, Normand MD, Corradini MG, Peleg M After a short time interval of length deltat during microbial growth and mortality, an individual cell can be found divided with a probability Pd(t)deltat, dead with a probability Pm(t)deltat, or alive but undivided with probability 1- (Pd (t) + Pm(t))deltat. These probabilities may change with the state of the population and the habitat's properties, and are therefore functions of time. This translates into a model that is presented in stochastic and deterministic versions. The first, a stochastic process model, follows the fate of individual cells and counts their number. It is particularly suitable for small ...

The role of extracellular polymeric substances in the surface chemical reactivity of Hymenobacter aerophilus, a psychrotolerant bacterium.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Baker MG, Lalonde SV, Konhauser KO, Foght JM Bacterial surface layers, such as extracellular polymeric substances (EPS), are known to play an important role in metal sorption and biomineralization, however there have been very few studies investigating how environmentally-induced changes in EPS production affect the cell's surface chemistry and reactivity. Acid-base titrations, cadmium adsorption assays and FT-IR were used to characterize the surface reactivity of Hymenobacter aerophilus cells with intact EPS (WC) or stripped of EPS (SC), and purified EPS alone. Linear programming modeling of titration data showed SC to possess functional groups corresponding to phosphoryl (pKa approximately 6.5), phosphoryl/amine (pKa approximately 7.9) and amine/hydroxyl (pKa approximately 9...

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Traceability of marketable Japanese shoro in New Zealand: Using multiplex PCR to exploit phylogeographic variation amongst taxa in the Rhizopogon subgenus roseoli.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

In this study, the ITS1-5.8S-ITS2 rRNA (ITS) region was used to examine the phylogenetic relationships of R. roseolus and other closely related fungi belonging to R. subgenus roseoli to determine the genetic basis for phenotypic differences amongst R. roseolus from different geographic regions. Phylogenetic comparison revealed phylogeographic variation within R. subgenus roseoli. Collections from the United States and Europe grouped into four distinct clades. Rhizopogon roseolus found in New Zealand were closely related to those from the United States, likely due to introduction of Pinus radiata from its native California, United States. In contrast, Japanese R. roseolus clustered closely to European collections. Phylogenetic differences between Japanese and New Zealand R. roseolus may exp...

TOLERANCE TO HOP ISO-{alpha}-ACIDS IN YEAST INVOLVES VACUOLAR SEQUESTRATION, AND ACTIVE TRANSPORT.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Hazelwood LA, Walsh MC, Pronk JT, Daran JM The hop plant, Humulus lupulus L., contains an exceptionally high content of secondary metabolites, the hop alpha-acids, which possess a range of beneficial properties including antiseptic action. Studies performed on the mode of action of hop iso-alpha-acids have hitherto been restricted to lactic acid bacteria. The present study investigates molecular mechanisms of hop iso-alpha-acid resistance in the model eukaryote Saccharomyces cerevisiae. Growth inhibition occurred at concentrations of hop iso-alpha-acids that were an order of magnitude higher than those found with hop-tolerant prokaryotes. Chemostat-based transcriptome analysis and phenotype screening of the S. cerevisiae haploid gene deletion collection were used as complement...

Expression of the Clostridium botulinum A2 Neurotoxin Gene Cluster Proteins and Characterization of the A2 Complex.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Lin G, Tepp WH, Pier CL, Jacobson MJ, Johnson EA Clostridium botulinum subtype A2 possesses a botulinum neurotoxin type A (BoNT/A) gene cluster consisting of an orfX cluster containing open reading frames (orfs) of unknown functions. To better understand the association between the BoNT/A2 complex proteins, first, the orfX cluster proteins (ORFX1, ORFX3, P47 and middle part of NTNH) from C. botulinum A2 (strain Kyoto F) and the NTNH of an A1 strain (ATCC 3502) were expressed using either E. coli or C. botulinum expression systems. Polyclonal antibodies against individual orfX cluster proteins were prepared by immunizing rabbits and mice against the expressed proteins. Antibodies were then utilized as probes to determine which of the A2 orfX cluster genes were expressed in the ...

Tertiary Structure and Characterization of a Glycoside Hydrolase Family 44 Endoglucanase from Clostridium acetobutylicum.

Applied and Environmental Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Warner CD, Hoy JA, Shilling TC, Linnen MJ, Ginder ND, Ford CF, Honzatko RB, Reilly PJ A gene encoding a glycoside hydrolase family 44 (GH44) protein from Clostridium aceto-butylicum ATCC 824 was synthesized and transformed into Escherichia coli. The previous-ly uncharacterized protein was expressed with a C-terminal His-tag and purified by nickel-nitrilotriacetic acid affinity chromatography. Crystallization and x-ray diffraction to 2.2-A resolution revealed a TIM barrel-like structure with additional Greek key and beta-sandwich folds, similar to other GH44 crystal structures. The enzyme hydrolyzes cellotetraose and larger cellooligosaccharides, yielding an unbalanced product distribution including some glucose. It attacks carboxymethylcellulose and xylan at approximately the ...

Prevention of Escherichia coli O157:H7 infection in gnotobiotic mice associated with Bifidobacterium strains.

Antonie van Leeuwenhoek — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Yoshimura K, Matsui T, Itoh K Previous reports have shown that Escherichia coli O157:H7 infection is strongly modified by intestinal microbes. In this paper, we examined whether bifidobacteria protect against E. coli O157:H7 infections using gnotobiotic mice di-associated with Bifidobacterium strains (6 species, 9 strains) and E. coli O157:H7. Seven days after oral administration of each Bifidobacterium strain, the mice were orally infected with E. coli O157:H7 and their mortality was examined. Bifidobacterium longum subsp. infantis 157F-4-1 (B. infantis 157F) and B. longum subsp. longum NCC2705 (B. longum NS) protected against the lethal infection, while mice associated with all other Bifidobacterium strains, including type strains of B. longum subsp. infantis and B. longum s...

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Aquimarina macrocephali sp. nov., isolated from the sediment adjacent to sperm whale carcasses off Kagoshima, Japan.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Miyazaki M, Nagano Y, Fujiwara Y, Hatada Y, Nogi Y A novel species was isolated from the sediment adjacent to sperm whale carcasses off Kagoshima, Japan, at a depth of 219 m. The isolated strain, JAMB N27(T), was Gram negative, rod shaped, non-spore forming, strictly aerobic and motile by gliding. It was able to produce isoprenoid quinones MK-6 as major components. The predominant fatty acids of the organisms were iso-C(15:0), iso-C(15:1), C(16:1) and C(17:1). Casein, chitin, gelatin and starch were degraded. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain JAMB N27 (T) represents a separate lineage within the genus Aquimarina. The G+C contents of the isolated strain was about 33.1 mol%. DNA-DNA hybridization values between the strain and Aquimarina ref...

Shewanella coralli sp. nov., a marine bacterium isolated from Red Sea corals.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Shnit-Orland M, Sivan A, Kushmaro A A marine bacterial strain, designated fav-2-10-05T, was isolated from the coral mucus layer of the coral Favia sp., collected from the coral reef in the Gulf of Eilat, Israel (29 degrees 51'N, 34 degrees 94'E). On the basis of 16S rRNA gene sequence comparisons, the isolate was affiliated with the family Shewanellaceae. Shewanella marisflavi and Shewanella haliotis were the closest relatives, demonstrating sequence similarities of 96.0 and 95.9 %, respectively, to the 16S rRNA gene of the isolate. The isolate was Gram-negative, rod-shaped and motile by means of a single polar flagellum, forming yellow- brownish colonies within 2 days of incubation at 26 degrees C. The isolate demonstrated antibacterial activity against indicator strains, and...

Revival and emended description of 'Mycobacterium paraffinicum' (Davis, Chase and Raymond 1956) as Mycobacterium paraffinicum (ex Davis, Chase and Raymond 1956) sp. nov., nom. rev.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Toney NC, Adekambi T, Toney S, Yakrus M, Butler WR The omission of the name 'Mycobacterium paraffinicum' from the 1980 Approved List of Bacterial Names was due to phenotypic confusion surrounding a close relationship with Mycobacterium scrofulaceum. Correspondingly 'M. paraffinicum' strains grew slowly in >7 days, stained acid-alcohol fast, produced yellow-pigmented smooth waxy colonies in the dark at an optimal temperature of 35 degrees C. However 'M. paraffinicum' strains demonstrated no activity for urease, nicotinamidase or pyrazinamidase, and lacked growth at 42 degrees C as compared to M. scrofulaceum. The mycolic acid pattern as determined by high performance liquid chromatography (HPLC) clustered 'M. paraffinicum' with M. scrofulaceum, Mycobacterium avium, and Mycob...

Euzebya tangerina gen. nov., sp. nov., a deeply branching marine actinobacterium isolated from the sea cucumber Holothuria edulis and proposal of Euzebyaceae fam. nov., Euzebyales ord. nov. and Nitriliruptoridae subclassis nov.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Kurahashi M, Fukunaga Y, Sakiyama Y, Harayama S, Yokota A A tangerine-coloured, Gram-positive actinobacterial strain, designated F10T, was isolated from the abdominal epidermis of a sea cucumber, Holothuria edulis, collected in seawater off the coast of Japan. A 16S rRNA gene sequence analysis indicated that strain F10T was a member of the class Actinobacteria and was most closely related to Nitriliruptor alkaliphilus ANL-iso2T (87.4% sequence similarity). Phylogenetic analyses showed that strain F10T represents a novel deep rooted, and distinct phylogenetic lineage within the class Actinobacteria and is clustered with N. alkaliphilus and uncultured bacteria. The organism had meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan, and rhamnose a...

Rhodotorula rosulata sp. nov., Rhodotorula silvestris sp. nov. and Rhodotorula straminea sp. nov., novel myo-inositol-assimilating yeast species in the Microbotryomycetes.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Golubev WI, Scorzetti G Three novel species are described as Rhodotorula rosulata (type strain VKM Y-2962), Rh. silvestris (type strain VKM Y-2971) and Rh. straminea (type strain VKM Y-2964) based on the study of eight isolates from needle litter. The new species, phylogenetically located within the Microbotryomyces, are related to glucuronate-assimilating species of the genus Rhodotorula. Sequencing of the D1/D2 domains of the LSU rDNA and the ITS regions, as well as physiological characterization, revealed their distinct taxonomic positions. PMID: 19915106 [PubMed - as supplied by publisher] (Source: International Journal of Systematic and Evolutionary Microbiology)

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Salinimicrobium marinum sp. nov., a novel halophilic bacterium of the family Flavobacteriaceae, and a proposal of the emended descriptions of the genus Salinimicrobium and species Salinimicrobium catena.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Nedashkovskaya OI, Vancanneyt M, Kim SB, Han J, Zhukova NV, Shevchenko LS Two novel heterotrophic, strictly aerobic, gliding and yellow-pigmented bacteria, designated strains KMM 6270T and KMM 6320, were isolated from different marine environments and subjected to a polyphasic taxonomic study. The 16S rRNA gene sequence analysis placed the novel strains within the family Flavobacteriaceae. Strains KMM 6270T and KMM 6320 were most closely related to the type strains of the recognized species of the genus Salinimicrobium with sequence similarity in range of 95.0-96.6%. The G+C content of the genomic DNA was 40-41 mol%. The strains grew with 0.5-15% NaCl and at 4-4 degrees C, and optimal growth was with 4% NaCl and at 28-32 degrees C. Aesculin and gelatin were hydrolyzed but agar...

Ogataea pignaliae sp. nov., the teleomorph of Candida pignaliae.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Péter G, Tornai-Lehoczki J, Dlauchy D Six ascosporulating Candida pignaliae strains were isolated from epigeal plant parts in Hungary. They share identical D1/D2 LSU rRNA gene sequences with the type strain of C. pignaliae, and the physiological characteristics investigated are also very similar to that of the type strain. The only substantial difference compared to the type strain of C. pignaliae is their ability to assimilate beta-glucosides (cellobiose, salicin and arbutin). The majority of the isolation sources of the strains reported in this study have the common feature of containing tannic acid, while the type strain of C. pignaliae was recovered from tanning fluid. We were able to induce ascosporulation also in the type strain of C. pignaliae. Therefore, Ogataea p...

Nocardioides mesophilus sp. nov., isolated from soil.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Dastager SG, Lee JC, Pandey A, Kim CJ A short coccoid- to rod-shaped, motile, mesophilic actinobacterium, strain MSL-22T, was isolated from soil on Bigeum Island, Korea. A polyphasic study was undertaken to establish the taxonomic position of this strain. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MSL-22T formed an evolutionary lineage within the radiation of the genus Nocardioides. In particular, it formed a monophyletic lineage with Nocardioides jensenii DSM 20641T with which it shares the highest sequence similarity of about 97.3%. However, DNA-DNA hybridization experiments demonstrated that strain MSL-22T is distinct from its closest phylogenetic neighbors. The cell-wall peptidoglycan of strain MSL-22T contained LL-diaminopimelic acid. The ...

Phylogeny and differentiation of species of the genus Gluconacetobacter and related taxa based on multilocus sequence analyses of housekeeping genes and reclassification of Acetobacter xylinus subsp. sucrofermentans as Gluconacetobacter sucrofermentans (Toyosaki et al. 1996) comb. nov.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Cleenwerck I, De Vos P, De Vuyst L Three housekeeping genes (dnaK, groEL, and rpoB) of strains belonging to the genus Gluconacetobacter (37 strains) or related taxa (38 strains) were sequenced. Reference strains of the fifteen species of the genus Gluconacetobacter were included. Phylogenetic trees generated using these gene sequences confirmed the existence of two phylogenetic groups within the genus Gluconacetobacter. These groups clustered separately in trees constructed using concatenated sequences of the three genes, indicating that the genus Gluconacetobacter should not remain a single genus, and be split up as previously suggested. Multilocus sequence analysis (MLSA) of the three housekeeping genes further showed useful for species differentiation in the family Acetobac...

Cohnella thailandensis sp. nov., a xylanolytic bacterium from Thai soil.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Khianngam S, Tanasupawat S, Akaracharanya A, Kim KK, Lee KC, Lee JS A xylanolytic bacterium, strain S1-3T was isolated from soil collected in Nan province, Thailand. It was characterized taxonomically based on its phenotypic characteristics and 16S rRNA gene sequence comparison. The strain was Gram-positive, facultatively anaerobic, spore forming rod-shaped bacterium. It contained meso-diaminopimelic in cell wall-peptidoglycan. Major menaquinone was MK-7. Anteiso-C15:0 (35.1%) and iso-C16:0 (33.2%) were predominant cellular fatty acids. Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were major polar lipids. The DNA G+C content was 53.3 mol%. Phylogenetic analysis using 16S rRNA gene sequences showed that strain S1-3T was affiliated to the genus Cohne...

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Nocardia mikamii sp. nov., isolated from human pulmonary infections in the United States.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Jannat-Khah DP, Kroppenstedt RM, Klenk HP, Spröer C, Schumann P, Lasker BA, Steigerwalt AG, Hinrikson HP, Brown JM Four nocardioform bacteria were isolated from clinical respiratory sources (W7467, W7811, W8061T and W9013) in the United States. Macroscopic examination showed scant aerial hyphae and beige-red substrate hyphae. They showed chemotaxonomic markers that were consistent with the classification of Nocardia: i.e., meso-diaminopimelic acid; arabinose and galactose as diagnostic sugars; the phospholipids diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides; a menaquinone with a omega-cyclic isoprene side chain MK-8(H4cycl.); a fatty acid pattern composed of unbranched saturated and monounsaturated fatty acids wi...

Haloterrigena daqingensis sp. nov., an extremely haloalkaliphilic archaeon isolated from salt-alkaline soils in Daqing, China.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Wang S, Yang Q, Liu Z, Sun L, Wei D, Zhang J, Song J, Yuan HF A haloalkaliphilic archaeon strain JX313T was isolated from the salt-alkaline soil from Daqing, Heilongjiang Province in China. Its morphological, physiological and biochemical features and 16S rRNA gene sequence were characterized. Colonies of the strain were orange-red and cells were non-motile cocci and Gram-variable. The strain requires at least 1.7 M NaCl for its growth with optimal growth occurring in 2.0-2.5 M NaCl. It grows in the range of 20-50 degrees C and pH 8.0-10.5, with optimal growth at 35 degrees C and pH 10.0. The G+C content of its genomic DNA was 59.3 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain JX313T is associated with the genera Haloterrigena and Natrinema and is m...

Clostridium arbusti sp. nov., an anaerobic bacterium isolated from pear orchard soil.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Jung MY, Park IS, Kim W, Kim HL, Paek WK, Chang YH An obligate anaerobic, spore-forming bacterial strain, designated SL206T, was isolated from pear orchard soils. Strain SL206T cells were straight or slightly curved rods, with motility by peritrichate flagella. The major fatty acids were C16:0, C18:1 cis 9, and summed feature 10 (containing C18:1 c11/t9/t6). Glucose was fermented to acetate and butyrate. The G+C content of the genomic DNA was 31.1 mol%. Based on comparative 16S rRNA gene sequence analysis, the isolate belonged to the genus Clostridium and formed a clade with C. pasteurianum. The most closely related species to SL206T were C. pasteurianum (98.6% similarity) and C. acidisoli (97.8% similarity). In DNA-DNA relatedness studies, the isolate had 59.5% homology with ...

Proteiniclasticum ruminis gen. nov., sp. nov., a strictly anaerobic proteolytic bacterium isolated from yak rumen.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Zhang K, Song L, Dong X Two strict anaerobic, proteolytic bacterial strains, designated as strain D3RC-2T and D3RC-3r were isolated from a cellulose-degrading mix-culture enriched from yak rumen content. The strains were Gram stain negative, non-spore-forming with cell size of 0.5-0.8 microm x 0.6-2.0 microm. Growth was observed in the temperature range between 24-46 degrees C (optimum 38-39 degrees C) and pH range between 5.6-8.7 (optimum 7.0-7.3). Two strains used Soja peptone, tryptone, L-phenylalanine, L-leucine, L-methionine, L-serine, L-valine, L-threonine and L-histidine as carbon and nitrogen sources, but did not use any of the tested saccharide. The major fermentation products of PY medium were acetate, propionate and iso-butyrate. The G+C content of strain D3RC-2T an...

Laceyella tengchongensis sp. nov., a thermophilic strain isolated from the Big Empty Volcano.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Zhang J, Tang SK, Zhang YQ, Yu LY, Klenk HP, Li WJ A thermophilic strain, designated YIM 10002T, was isolated from a soil sample of the Big Empty Volcano in Tengchong county, Yunnan province, south-west China. A polyphasic approach was used in investigating the taxonomic position of the novel strain. The strain YIM 10002T formed endospores on both aerial and substrate mycelia. The whole cell hydrolysates contained meso-diaminopimelic acid, ribose, xylose and glucose. The major fatty acids were iso-C15:0 and anteiso-C15:0. The predominant menaquinone was MK-9. Phospholipids consisted of DPG, PG, PE, PI and PIM, together with some unknown phospholipids. The G+C content of its genomic DNA was 48.6 mol%. All these chemotaxonomic data together with its morphological properties cons...

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Listeria rocourtiae sp. nov.

International Journal of Systematic and Evolutionary Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Leclercq A, Clermont D, Bizet C, Grimont PA, Le Flèche-Matéos A, Roche SM, Buchrieser C, Cadet-Daniel V, Le Monnier A, Lecuit M, Allerberger F A Listeria-like strain isolated in Austria from pre-cut lettuce fitted with the description of the genus Listeria although it could not be assigned to any of the known species. Comparison of the rrs gene (coding 16S rRNA) sequence and gene content by DNA-array indicates affiliation to the genus Listeria. Phylogenetic distance with known Listeria species indicates it represents a new species. Since it can be differentiated from all other known species of Listeria by using phenotypic tests, the name Listeria rocourtiae is proposed for the new species. The type strain is CIP 109804(T) (= DSM 22097(T), Allerberger 700284/02(T)). T...

Cloning, expression in Pichia pastoris, and characterization of a thermostable GH5 mannan endo-1,4-beta-mannosidase from Aspergillus niger BK01

Microbial Cell Factories — Fri, 13 Nov 2009 00:00:00 +0100

Conclusions: This study is the first report on the cloning and expression of the thermostable mannan endo-1,4-beta-mannosidase from A. niger in Pichia pastoris. The efficient expression and ease of purification will significantly decrease the production costs of this enzyme. Taking advantage of its acidic pH optimum and high thermostability, this recombinant beta-mannanase will be valuable in various biotechnological applications. (Source: Microbial Cell Factories)

Mutation of CRE1 in Fusarium oxysporum reverts the pathogenicity defects of the FRP1 deletion mutant

Molecular Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

The F-box protein Frp1 is required for pathogenicity of Fusarium oxysporum f. sp. lycopersici towards tomato. The [Delta]frp1 mutant is deficient in expression of genes for cell wall-degrading enzymes (CWDEs) and ICL1, encoding a key enzyme for the assimilation of C2 carbon sources. An explanation for the inability of the [Delta]frp1 mutant to express these genes may be found in constitutive carbon catabolite repression. Cre1 is the transcriptional repressor in filamentous fungi known to repress several CWDE genes and other genes required for assimilation of non-sugar carbon sources. Here, we demonstrate that Frp1 and Cre1 both control the repression/derepression state of such genes. The replacement of CRE1 with GST::CRE1 resulted in a derepressed phenotype in wild-type background, suggest...

Co-evolution of multipartite interactions between an extended tmRNA tag and a robust Lon protease in Mycoplasma

Molecular Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Messenger RNAs that lack in-frame stop codons promote ribosome stalling and accumulation of aberrant and potentially harmful polypeptides. The SmpB-tmRNA quality control system has evolved to solve problems associated with non-stop mRNAs, by rescuing stalled ribosomes and directing the addition of a peptide tag to the C-termini of the associated proteins, marking them for proteolysis. In Escherichia coli, the ClpXP system is the major contributor to disposal of tmRNA-tagged proteins. We have shown that the AAA+ Lon protease can also degrade tmRNA-tagged proteins, but with much lower efficiency. Here, we present a unique case of enhanced recognition and degradation of an extended Mycoplasma pneumoniae (MP) tmRNA tag by the MP-Lon protease. We demonstrate that MP-Lon can efficiently and sele...

Detection of Staphylococcus lugdunensis by a new species-specific PCR based on the fbl gene

FEMS Immunology and Medical Microbiology — Fri, 13 Nov 2009 00:00:00 +0100

Staphylococcus lugdunensis are unusually virulent coagulase-negative staphylococci associated with skin infections and endocarditis. We developed an accurate and simple PCR assay to identify S. lugdunensis isolates based on detection of the fbl gene, which encodes a fibrinogen-binding protein involved in pathogen adhesion. The PCR assay was established using 16 reference strains of different Staphylococcus species and further validated with a collection of 63 clinical staphylococcal isolates that were also phenotypically characterized. Reliable results for the detection of S. lugdunensis isolates were obtained for 100% of the strains evaluated, indicating that this PCR assay can be used in the routine of microbiology laboratories as one more tool for correct species differentiation. (Sourc...

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Effect of cyclic bis(3'–5')diguanylic acid and its analogs on bacterial biofilm formation

FEMS Microbiology Letters — Fri, 13 Nov 2009 00:00:00 +0100

Cyclic bis(3'[ndash]5')diguanylic acid (cyclic-di-GMP) functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes. We measured cyclic-di-GMP and its structural analogs such as cyclic bis(3'[ndash]5')guanylic/adenylic acid (cyclic-GpAp), cyclic bis(3'[ndash]5')guanylic/inosinic acid (cyclic-GpIp) and monophosphorothioic acid of cyclic-di-GMP (cyclic-GpGps) for effects on the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. We constructed a knockout mutant of SA0701, which is a GGDEF motif protein relevant to diguanylate cyclase from S. aureus 2507. We confirmed that the biofilm formation of this mutant (MS2507[Delta]SA0701) was reduced. Cyclic-di-GMP corresponding to physiological intracellular levels given in the cultu...

Correction: Are we aware how contaminated our mobile phones with nosocomial pathogens?

Annals of Clinical Microbiology and Antimicrobials — Fri, 13 Nov 2009 00:00:00 +0100

The following reference, "Jeske HC, Tiefenthaler W, Hohlrieder M, Hinterberger G, Benzer A. Bacterial contamination of anaesthetists' hands by personal mobile phone and fixed phone use in the operating theatre. Anaesthesia 2007, 62(9):904-6." was omitted mistakenly at the background section and should be added to literature sited section of this manuscript. The author regrets for the oversights and thanks to editors forgiving opportunity to both cite and give proper credit to Dr. Jeske's study. (Source: Annals of Clinical Microbiology and Antimicrobials)

Outcome of antibiotic lock technique for persistent central venous catheter-associated coagulase-negative Staphylococcus bacteremia in children

European Journal of Clinical Microbiology & Infectious Diseases — Thu, 12 Nov 2009 18:40:30 +0100

Abstract The purpose of this study was to assess the long-term effectiveness of the antibiotic lock technique (ALT) in conjunction with systemic antibiotics for the salvage of long-term central venous catheter (CVC)-associated coagulase-negative Staphylococcus (CONS) bloodstream infections (BSIs) in children. A retrospective study of children with CVC-associated CONS BSIs treated with systemic vancomycin and ALT with vancomycin was carried out. The primary outcome was the immediate and 3-month success rate of salvage of the CVC. During the study period, 23 patients had persistent CONS bacteremia and were treated with ALT and systemic vancomycin. Of the 23 vancomycin lock treatments, eight catheters were removed during the acute event because of persistent bacteremia, six ha...

Characterisation of MRSA from Malta and the description of a Maltese epidemic MRSA strain

European Journal of Clinical Microbiology & Infectious Diseases — Thu, 12 Nov 2009 18:40:28 +0100

Abstract Malta has one of the highest prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA) in Europe. However, only limited typing data are currently available. In order to address this situation, 45 MRSA isolates from the Mater Dei Hospital in Msida, Malta, were characterised using DNA microarrays. The most common strain was ST22-MRSA-IV (UK-EMRSA-15, 30 isolates). Sporadic strains included ST36-MRSA-II (UK-EMRSA-16, two isolates), PVL-positive ST80-MRSA-IV (European Clone, one isolate), ST228-MRSA-I (Italian Clone/South German Epidemic Strain, one isolate) and ST239-MRSA-III (Vienna/Hungarian/Brazilian Epidemic Strain, one isolate). Ten MRSA isolates belonged to a clonal complex (CC) 5/ST149, spa type t002 strain. This strain harboured an SCCmec IV elemen...

First detection and molecular identification of Borrelia garinii isolated from human skin in Taiwan.

Journal of Medical Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Chao LL, Chen YJ, Shih CM Borrelia garinii, a causative agent for Lyme disease, was detected and identified from human skin for the first time in Taiwan. Lyme disease infection was confirmed by Western immunoblot tests and isolation of Borrelia spirochetes from skin biopsy specimens. The genetic identity of this detected spirochete was determined by analyzing the gene sequence amplified by a genospecies-specific polymerase chain reaction (PCR) assay based on the 5S (rrf)-23S (rrl) intergenic spacer amplicon gene of B. burgdorferi sensu lato. Phylogenetic analysis reveals that the sequence similarity of this detected spirochete is highly homogeneous (97.7%-98.5%) within the genospecies of B. garinii and can be distinguished clearly from other genospecies of Borrelia spirochetes...

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Killing of adherent microbes by a non-thermal atmospheric plasma jet.

Journal of Medical Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Conclusion: Non-thermal atmospheric plasma jets can be used for the disinfection of dental surfaces. PMID: 19910483 [PubMed - as supplied by publisher] (Source: Journal of Medical Microbiology)

Management of obstructive renal failure caused by bilateral renal aspergilloma in an immunocompetent newborn.

Journal of Medical Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Martinez-Pajares JD, Martinez-Ferriz C, Moreno-Perez D, Garcia-Ramirez M, Martin-Carballido S, Blanch-Iribarne P Kidneys fungal infection is a rare condition which has been reported in premature babies and in diabetic or immunocompromised adult patients. Candida spp is the most frequent microorganism involved. This paper reports a case of an immunocompetent newborn with a bladder exstrophy who suffered from an acute renal failure caused by bilateral renal aspergilloma (Aspergillus flavus). The newborn was treated with amphotericin B urinary tract irrigation through bilateral nephrostomy catheters combined with liposomal amphotericin B and voriconazole therapy, which improved his renal function. However, due to persistent fungal colonization, long antifungal treatment and perma...

Traumatic endophthalmitis caused by Staphylococcus gallinarum.

Journal of Medical Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Tibra NK, Jalali S, Reddy AK, Narayanan R, Agarwal R Herein, we describe what is believed to be the first case of traumatic endophthalmitis caused by Staphylococcus gallinarum following injury with an iron nail. The patient was successfully treated with vitrectomy and intravitreal injection of cefazolin and vancomycin. PMID: 19910485 [PubMed - as supplied by publisher] (Source: Journal of Medical Microbiology)

Integrating Multiple "Omics" Analysis for Microbial Biology: Application and Methodologies.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Zhang W, Li F, Nie L Recent advances in various "omics" technologies enable quantitative monitoring of the abundance of various biological molecules in a high throughput manner, and thus allow determination of their variation between different biological states on a genomic scale. Several popular "omics" platforms that have been used in microbial systems biology include: transcriptomics that measures messenger RNA transcript levels, proteomics that quantifies protein abundance, metabolomics that determines abundance of small cellular metabolites, interactomics that resolves the whole set of molecular interactions in cells, and fluxomics that establishes dynamic changes of molecules within a cell over time. However, no single "omics" analysis can fully unravel the complexities ...

Poly(A) polymerase 1 (PAP1) homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole resistant clinical isolates of Candida albicans.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

This study examines the molecular mechanisms underlying enhanced CDR1 mRNA stability in AR isolates. Mapping of the 3'UTR of CDR1 revealed that it was rich in 'AU' (Adenylate-Uridylate) elements, possessed heterogeneous polyadenylation sites, and had putative consensus sequences for RNA-binding proteins. Swapping of heterologous and chimeric lacZ-CDR1 3'UTR transcriptional reporter fusion constructs did not alter the reporter activity in AS and AR isolates, indicating that cis-acting sequences within the CDR1 3'UTR itself are not sufficient to confer the observed differential mRNA decay. Interestingly, the poly(A) tail of the CDR1 mRNA of AR isolates was approximately 35-50% hyperadenylated as compared with AS isolates. C. albicans poly(A) polymerase (PAP1) responsible for mRNA adenylation...

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Analysis of adherence, biofilm formation, and cytotoxicity suggest a greater virulence potential of Gardnerella vaginalis relative to other bacterial vaginosis-associated anaerobes.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

This study suggests that G. vaginalis is more virulent than other BV-associated anaerobes, and that many of the bacterial species frequently isolated from BV may be relatively avirulent opportunists that colonize the vagina after G. vaginalis has initiated an infection. PMID: 19910411 [PubMed - as supplied by publisher] (Source: Microbiology)

Autophagy is Involved in Starvation Response and Cell Death in Blastocystis.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

In this study, we investigated if Blastocystis underwent autophagy upon amino acid starvation and rapamycin treatment. Concurrently, we have provided new insight on a possible function of the central vacuole. The use of autophagic marker monodansylcadaverine (MDC) and autophagic inhibitor 3-methyladenine and wortmannin showed the existence of autophagy in amino acid-starved and rapamycin-treated Blastocystis. Confocal microscopy and transmission electron microscopic studies also showed morphological changes suggestive of autophagy. The unusually large size of the autophagic compartments within the parasite central vacuole was found to be unique in Blastocystis. In addition, autophagy was found to be triggered when cells were exposed to a cytotoxic antibody MAb 1D5 and intensified in the pr...

A 2-oxoacid dehydrogenase complex of Haloferax volcanii is essential for growth on isoleucine but not the other branched chain amino acids.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Sisignano M, Morbitzer D, Gägens J, Oldiges M, Soppa J The halophilic archaeon Haloferax volcanii contains three operons encoding 2-oxoacid dehydrogenase complexes (OADHCs), OADHC1 to OADHC3. However, the biological role of none of the three OADHCs is known, since previous studies had come to the conclusion that they cannot use any of the known OADHC substrates. Even the construction of single mutants in all three oadhc operons, reported recently, could not lead to the identification of a substrate. Therefore, all three possible double mutants and a triple mutant were generated, and single, double and triple mutants were compared to the wildtype. The four mutants devoid of a functional OADHC1 had a reduced growth yield during nitrate-respirative growth on tryptone. A "met...

Role of Host Cell Polarity and Leading Edge Properties in Pseudomonas Type III Secretion.

Microbiology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Bridge DR, Novotny MJ, Moore ER, Olson JC Type III secretion (T3S) functions in establishing infections in a large number of Gram-negative bacteria, yet little is known about how host cell properties might function in this process. We used the opportunistic pathogen, Pseudomonas aeruginosa, and the ability to alter host cell sensitivity to Pseudomonas T3S to explore this problem. HT-29 epithelial cells were used to study cellular changes associated with loss of T3S sensitivity, which could be induced by treatment with methyl-beta-cyclodextrin or perfringolysin O. HL-60 promyelocytic cells are innately resistant to Pseudomonas T3S and were used to study cellular changes occurring in response to induction of T3S sensitivity, which occurred following treatment with phorbol esters...

Variations of bacterial 16S rDNA phylotypes prior to and after chlorination for drinking water production from two surface water treatment plants.

Journal of Industrial Microbiology and Biotechnology — Thu, 12 Nov 2009 00:00:00 +0100

We examined the variations of bacterial populations in treated drinking water prior to and after the final chlorine disinfection step at two different surface water treatment plants. For this purpose, the bacterial communities present in treated water were sampled after granular activated carbon (GAC) filtration and chlorine disinfection from two drinking water treatment plants supplying the city of Paris (France). Samples were analyzed after genomic DNA extraction, polymerase chain reaction (PCR) amplification, cloning, and sequencing of a number of 16S ribosomal RNA (rRNA) genes. The 16S rDNA sequences were clustered into operational taxonomic units (OTUs) and the OTU abundance patterns were obtained for each sample. The observed differences suggest that the chlorine disinfection step ma...

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Carbohydrate-binding domains: multiplicity of biological roles.

Applied Microbiology and Biotechnology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Guillén D, Sánchez S, Rodríguez-Sanoja R Insoluble polysaccharides can be degraded by a set of hydrolytic enzymes formed by catalytic modules appended to one or more non-catalytic carbohydrate-binding modules (CBM). The most recognized function of these auxiliary domains is to bind polysaccharides, bringing the biocatalyst into close and prolonged vicinity with its substrate, allowing carbohydrate hydrolysis. Examples of insoluble polysaccharides recognized by these enzymes include cellulose, chitin, beta-glucans, starch, glycogen, inulin, pullulan, and xylan. Based on their amino acid similarity, CBMs are grouped into 55 families that show notable variation in substrate specificity; as a result, their biological functions are miscellaneous. Carbohydrate or poly...

Purification and characterization of acetophenone reductase with excellent enantioselectivity from Geotrichum candidum NBRC 4597.

Applied Microbiology and Biotechnology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Nakata Y, Fukae T, Kanamori R, Kanamaru S, Matsuda T NADH-dependent enzyme reducing acetophenone derivatives with high stereoselectivities and wide substrate specificities from Geotrichum candidum NBRC 4597 was isolated, purified, characterized, and used for asymmetric synthesis. Through five-step purification including ammonium sulfate fractionation and a series of chromatographies, the enzyme was purified about 150-fold with a yield of 5.6%. The active enzyme has a molecular mass of 73 kDa determined by gel filtration chromatography, and the SDS-PAGE result reveals that the molecular size of the subunit is 36 kDa. These results indicate that the enzyme consists of a homodimer of a 36 kDa subunit. The acetophenone reductase exhibited the highest activity at 50 degrees C and o...

Cloning, overexpression, and characterization of recombinant heparinase III from Bacteroides stercoris HJ-15.

Applied Microbiology and Biotechnology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Hyun YJ, Lee JH, Kim DH Recombinant heparinase III (rHepIII) from Bacteroides stercoris HJ-15 was cloned, expressed, and characterized. The full-length heparinase III gene from B. stercoris HJ-15 was identified by Southern blotting, and the sequence was deposited in GenBank. The heparinase III gene, which is 2,001-bp long, was cloned and overexpressed in Escherichia coli; highly active rHepIII was easily purified using only one step of immobilized Ni(2+) affinity column chromatography. Enzymatic properties and substrate specificities of rHepIII were assessed, and its kinetic constants were calculated. rHepIII was most active in 50 mM sodium phosphate buffer with 350 mM NaCl (pH 6.6) at 45 degrees C. Through amino acid modification studies and site-directed mutagenesis assay, c...

A novel expression system for intracellular production and purification of recombinant affinity-tagged proteins in Aspergillus niger.

Applied Microbiology and Biotechnology — Thu, 12 Nov 2009 00:00:00 +0100

Authors: Roth AH, Dersch P A set of different integrative expression vectors for the intracellular production of recombinant proteins with or without affinity tag in Aspergillus niger was developed. Target genes can be expressed under the control of the highly efficient, constitutive pkiA promoter or the novel sucrose-inducible promoter of the beta-fructofuranosidase (sucA) gene of A. niger in the presence or absence of alternative carbon sources. All expression plasmids contain an identical multiple cloning sequence that allows parallel construction of N- or C-terminally His(6)- and StrepII-tagged versions of the target proteins. Production of two heterologous model proteins, the green fluorescence protein and the Thermobifida fusca hydrolase, proved the functionality of the vector sy...