• Biostatistics To Evaluate Vaccine Efficacy, The Study Of The Spread Of Infectious Diseases: M. Elizabeth Halloran Named AAAS Fellow

    Updated: 2009-12-31 08:00:00
    Fred Hutchinson Cancer Research Center scientist M. Elizabeth "Betz" Halloran, M.D., M.P.H., D.S.c., has been awarded the distinction of AAAS Fellow. Election as a Fellow is an honor bestowed upon members of the American Association for the Advancement of Science, or AAAS, by their peers...

  • Correction: Maternal and Neonatal Herpes Simplex Virus Infections

    Updated: 2009-12-30 21:56:23
    To the Editor: In their informative review article on infection with herpes simplex virus (HSV), Corey and Wald (Oct. 1 ...

  • Technological properties of bakers' yeasts in durum wheat semolina dough.

    Updated: 2009-12-28 23:00:00
    This study showed an appreciable biodiversity in the microbial populations of both wild and commercial yeast strains. PMID: 20039189 [PubMed - as supplied by publisher] (Source: Journal of Industrial Microbiology and Biotechnology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Bacterial assay for the rapid assessment of antifouling and fouling release properties of coatings and materials.

    Updated: 2009-12-28 23:00:00
    Authors: D'Souza F, Bruin A, Biersteker R, Donnelly G, Klijnstra J, Rentrop C, Willemsen P An assay has been developed to accurately quantify the growth and release behaviour of bacterial biofilms on several test reference materials and coatings, using the marine bacterium Cobetia marina as a model organism. The assay can be used to investigate the inhibition of bacterial growth and release properties of many surfaces when compared to a reference. The method is based upon the staining of attached bacterial cells with the nucleic acid-binding, green fluorescent SYTO 13 stain. A strong linear correlation exists between the fluorescence of the bacterial suspension measured (RFU) using a plate reader and the total bacterial count measured with epifluorescence microscopy. This relationship ...

  • Ergot alkaloid biosynthesis in Aspergillus fumigatus: conversion of chanoclavine-I to chanoclavine-I aldehyde catalyzed by a short-chain alcohol dehydrogenase FgaDH.

    Updated: 2009-12-28 23:00:00
    Authors: Wallwey C, Matuschek M, Li SM Ergot alkaloids are toxins and important pharmaceuticals which are produced biotechnologically on an industrial scale. A putative gene fgaDH has been identified in the biosynthetic gene cluster of fumigaclavine C, an ergot alkaloid of the clavine-type. The deduced gene product FgaDH comprises 261 amino acids with a molecular mass of about 27.8 kDa and contains the conserved motifs of classical short-chain dehydrogenases/reductases (SDRs), but shares no worth mentioning sequence similarity with SDRs and other known proteins. The coding region of fgaDH consisting of two exons was amplified by PCR from a cDNA library of Aspergillus fumigatus, cloned into pQE60 and overexpressed in E. coli. The soluble tetrameric His(6)-FgaDH was purified to apparent ...

  • Enhancing functional expression of heterologous lipase B in Escherichia coli by extracellular secretion.

    Updated: 2009-12-28 23:00:00
    Authors: Narayanan N, Khan M, Chou CP Functional expression of recombinant Pseudozyma antarctica lipase B (PalB) in Escherichia coli has been technically problematic due to protein misfolding, ineffective disulfide bond formation, and protein instability associated with intracellular proteolysis. To overcome these problems, an alternative approach was explored in this study by extracellular secretion of PalB via two Sec-independent secretion systems, i.e., the alpha-hemolysin (type I) and the modified flagellar (type III) secretion systems, which can export proteins of interest from the cytoplasm directly to the exterior of the cell. Both shaker flask and bioreactor cultivations were performed to characterize the developed PalB expression/secretion systems. Bioactive PalB was expressed...

  • Rumen Bacterial Diversity Dynamics Associated with Changing from Bermudagrass Hay to Grazed Winter Wheat Diets.

    Updated: 2009-12-28 23:00:00
    Authors: Pitta DW, Pinchak WE, Dowd SE, Osterstock J, Gontcharova V, Youn E, Dorton K, Yoon I, Min BR, Fulford JD, Wickersham TA, Malinowski DP Rumen bacterial communities in forage-fed and grazing cattle continually adapt to a wide range of changing dietary composition, nutrient density, and environmental conditions. We hypothesized that very distinct community assemblages would develop between the fiber and liquid fractions of rumen contents in animals transitioned from bermudagrass hay diet to a grazed wheat diet. To address this hypothesis, we designed an experiment utilizing a 16S-based bTEFAP pyrosequencing technique to characterize and elucidate changes in bacterial diversity among the fiber and liquid rumen fractions and whole rumen contents of 14 (Angus x Hereford) ruminally c...

  • Genome organisation of the marine Roseobacter clade member Marinovum algicola.

    Updated: 2009-12-28 23:00:00
    Authors: Pradella S, Päuker O, Petersen J The Roseobacter clade, belonging to the family Rhodobacteraceae of the class Alphaproteobacteria, is one of the major bacterial groups in marine environments. A remarkable wealth of diverse large plasmids has been detected in members of this lineage. Here, we analysed the genome structure and extrachromosomal DNA content of four strains of the roseobacter species Marinovum algicola by pulsed-field gel electrophoresis. They were originally isolated from toxic dinoflagellates and possess multireplicon genomes with sizes between 5.20 and 5.35 Mb. In addition to the single circular chromosomes (3.60-3.74 Mb), whose organisation seem to be conserved, 9 to 12 extrachromosomal replicons have been detected for each strain. This number is unprecede...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Saccharomyces cerevisiae CCMI 885 secretes peptides that inhibit the growth of some non-Saccharomyces wine-related strains.

    Updated: 2009-12-28 23:00:00
    Authors: Albergaria H, Francisco D, Gori K, Arneborg N, Gírio F The nature of the toxic compounds produced by Saccharomyces cerevisiae CCMI 885 that induce the early death of Hanseniaspora guilliermondii during mixed fermentations, as well as their ability to inhibit the growth of other non-Saccharomyces wine-related strains, was investigated. The killing effect of mixed supernatants towards H. guilliermondii was inactivated by protease treatments, thus revealing the proteinaceous nature of the toxic compounds. Analysis of the protein pattern of mixed supernatants on Tricine SDS-PAGE showed that this S. cerevisiae strain secretes peptides (<10 kDa), which were detected only when death of H. guilliermondii was already established. Death-inducing supernatants were ultrafiltrated ...

  • Light/electricity conversion by a self-organized photosynthetic biofilm in a single-chamber reactor.

    Updated: 2009-12-28 23:00:00
    Authors: Nishio K, Hashimoto K, Watanabe K Biological energy-conversion systems are attractive in terms of their self-sustaining and self-organizing nature and are expected to be applied to low-cost and environment-friendly processes. Here we show a biofilm-based light/electricity-conversion system that was self-organized from a natural microbial community. A bioreactor equipped with an air cathode and graphite-felt anode was inoculated with a green hot-spring microbial mat. When the reactor was irradiated with light, electric current was generated between the anode and cathode in accordance with the formation of green biofilm on the anode. Fluorescence microscopy of the green biofilm revealed the presence of chlorophyll-containing microbes of approximately 10 microm in size, and these...

  • Biochemical features of microbial keratinases and their production and applications.

    Updated: 2009-12-28 23:00:00
    Authors: Brandelli A, Daroit DJ, Riffel A Keratinases are exciting proteolytic enzymes that display the capability to degrade the insoluble protein keratin. These enzymes are produced by diverse microorganisms belonging to the Eucarya, Bacteria, and Archea domains. Keratinases display a great diversity in their biochemical and biophysical properties. Most keratinases are optimally active at neutral to alkaline pH and 40-60 degrees C, but examples of microbial keratinolysis at alkalophilic and thermophilic conditions have been well documented. Several keratinases have been associated to the subtilisin family of serine-type proteases by analysis of their protein sequences. Studies with specific substrates and inhibitors indicated that keratinases are often serine or metalloproteases with...

  • A novel xyloglucan-specific endo-beta-1,4-glucanase: biochemical properties and inhibition studies.

    Updated: 2009-12-28 23:00:00
    Authors: Wong DD, Chan VJ, McCormack AA, Batt SB A novel xyloglucan-specific endo-beta-1,4-glucanase gene (xeg5A) was isolated, cloned, and expressed in Esherichia coli. The enzyme XEG5A consisted of a C-terminal catalytic domain and N-terminal sequence of ~90 amino acid residues with unknown function. The catalytic domain assumed an (alpha/beta)(8)-fold typical of glycoside hydrolase (GH) family 5, with the two catalytic residues Glu240 and Glu362 located on opposite sides of the surface groove of the molecule. The recombinant enzyme showed high specificity towards tamarind xyloglucan and decreasing activity towards xyloglucan oligosaccharide (HDP-XGO), carboxymethyl cellulose, and lichenan. Tamarind xyloglucan was hydrolyzed to three major fragments, XXXG, XXLG/XLXG, and XLLG. The hy...

  • Rapid discrimination and classification of the Lactobacillus plantarum group based on a partial dnaK sequence and DNA fingerprinting techniques.

    Updated: 2009-12-28 23:00:00
    In this study, we compared the use of two different molecular markers, the 16S rRNA and dnaK gene, for discriminating phylogenetic relationships amongst L. plantarum strains using sequencing and DNA fingerprinting. The average sequence similarity for the dnaK gene (89.2%) among five type strains was significantly less than that for the 16S rRNA (99.4%). This result demonstrates that the dnaK gene sequence provided higher resolution than the 16S rRNA and suggests that the dnaK could be used as an additional phylogenetic marker for L. plantarum. Species-specific profiles of the Lactobacillus strains were obtained with RAPD and RFLP methods. Our data indicate that phylogenetic relationships between these strains are easily resolved using sequencing of the dnaK gene or DNA fingerprinting assay...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Cloning and Nucleotide Sequences of Carbazole Degradation Genes from Marine Bacterium Neptuniibacter sp. Strain CAR-SF.

    Updated: 2009-12-28 23:00:00
    Authors: Nagashima H, Zulkharnain AB, Maeda R, Fuse H, Iwata K, Omori T The marine bacterium Neptuniibacter sp. strain CAR-SF utilizes carbazole as its sole carbon and nitrogen sources. Two sets of clustered genes related to carbazole degradation, the upper and lower pathways, were obtained. The marine bacterium genes responsible for the upper carbazole degradation pathway, carAa, carBa, carBb, and carC, encode the terminal oxygenase component of carbazole 1,9a-dioxygenase, the small and large subunits of the meta-cleavage enzyme, and the meta-cleavage compound hydrolase, respectively. The genes involved in the lower degradation pathway encode the anthranilate dioxygenase large and small subunit AntA and AntB, anthranilate dioxygenase reductase AntC, 4-oxalocrotonate tautomerase, and c...

  • Co-Existence of Multidrug-Resistant and -Susceptible Strains of Pseudomonas aeruginosa from a Single Clinical Isolate.

    Updated: 2009-12-28 23:00:00
    Authors: Mahida K, Kwon DH Pseudomonas aeruginosa is a leading cause of hospital-acquired infections and difficult to treat due to acquired-resistance to multiple antibiotics. A pair of strains, M38100A and M38100B, previously identified from a single clinical isolate of P. aeruginosa was investigated to understand phenotypic and genotypic characteristics. Results revealed that the pair of strains was very similar for serum susceptibility, growth rate in a complex medium (Luria-Bertani), RAPD-genotype profiles, status of genes encoding type III secretion toxins, and no extra-chromosomal DNA. However, antibiotic susceptibility of the strain M38100B showed resistant to all tested-antibiotics while the strain M38100A showed susceptible to the same tested-antibiotics as similar levels of P...

  • Tuning microbial hosts for membrane protein production

    Updated: 2009-12-28 23:00:00
    The last four years have brought exciting progress in membrane protein research. Finally those many efforts that have been put into expression of eukaryotic membrane proteins are coming to fruition and enable to solve an ever-growing number of high resolution structures. In the past, many skilful optimization steps were required to achieve sufficient expression of functional membrane proteins. Optimization was performed individually for every membrane protein, but provided insight about commonly encountered bottlenecks and, more importantly, general guidelines how to alleviate cellular limitations during microbial membrane protein expression. Lately, systems-wide analyses are emerging as powerful means to decipher cellular bottlenecks during heterologous protein production and their use in...

  • Molecular characterisation of Vibrio cholerae O1 strains carrying an SXT/R391-like element from cholera outbreaks in Kenya: 1994-2007

    Updated: 2009-12-28 23:00:00
    Conclusions: This study demonstrates that the V.cholerae O1 strains carrying an SXT/R391-like element implicated in recent cholera outbreaks in Kenya has not changed significantly between 1994 and 2007 and are clonally related. (Source: BMC Microbiology - Latest articles)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Effectiveness of a procalcitonin algorithm to guide antibiotic therapy in respiratory tract infections outside of study conditions: a post-study survey

    Updated: 2009-12-28 18:19:48
    This study investigates the effectiveness of PCT guidance in an observational quality control survey. We monitored antibiotic therapy and algorithm adherence in consecutive patients with respiratory tract infections admitted to the Kantonsspital Aarau, Switzerland, between May 2008 and February 2009. The results were compared to the site-specific results of the former ProHOSP study. Overall and more pronounced for patients with community-acquired pneumonia, the median duration of antibiotic treatment in this survey was shorter than the ProHOSP control patients (6 vs. 7 ays, P = 0.048 and 7 vs. 9 ays, P < 0.001). In 72.5% of patients, antibiotics were administered according to the prespecified PCT algorithm. No significant differences concerning adverse medical ...

  • Detection of KPC in Acinetobacter sp. in Puerto Rico.

    Updated: 2009-12-27 23:00:00
    Authors: Robledo IE, Aquino EE, Santé MI, Santana JL, Otero DM, León CF, Vázquez GJ During an island wide PCR-based surveillance study of beta-lactam resistance in multidrug resistant (MDR) Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter calcoaceticus-baumannii complex obtained from 17 different hospitals, 10 KPC positive Acinetobacter isolates were identified. DNA sequencing of blaKPC gene identified KPC-2, -3, -4 and a novel variant, KPC-10. This is the first report of a KPC-type ss-lactamase identified in Acinetobacter species. PMID: 20038618 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Stage-Dependent Inhibition of HIV-1 Replication by Antiretroviral Drugs in Cell Culture.

    Updated: 2009-12-27 23:00:00
    Authors: Donahue DA, Sloan RD, Kuhl BD, Bar-Magen T, Schader SM, Wainberg MA Recent clinical trials have shown that use of the HIV-1 integrase (IN) inhibitor raltegravir (RAL) resulted in more rapid drops in viral load compared to use of the reverse transcriptase (RT) inhibitor efavirenz (EFV). Previously, mathematical modeling of viral load decay that takes into account the stage of viral replication targeted by a drug has yielded data that closely approximate the clinical trial results. This model predicts greater inhibition of viral replication by drugs that act later in the viral replication cycle. Here, we have added drugs that target entry, reverse transcription, integration or proteolytic processing to acutely infected cells, and have shown modest viral inhibition by entry inhib...

  • Antimicrobial Susceptibility of Multidrug-Resistant Campylobacter jejuni and C. coli strains: in vitro Activities of 20 Antimicrobial Agents.

    Updated: 2009-12-27 23:00:00
    Authors: Lehtopolku M, Nakari UM, Kotilainen P, Huovinen P, Siitonen A, Hakanen AJ There is a paucity of information regarding antimicrobial agents suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents potentially effective towards multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobial agents against 238 Campylobacter spp. strains were analyzed by determining the MICs by the agar plate dilution method or the Etest. These strains were selected from 1808 Campylobacter spp. isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters </=23 m...

  • Pharmacokinetics of anti tuberculosis drugs in pulmonary tuberculosis patients with type-2 diabetes.

    Updated: 2009-12-27 23:00:00
    Conclusion Diabetes does not alter the pharmacokinetics of anti tuberculosis drugs during the intensive phase of tuberculosis treatment. Reduced exposure to rifampicin in diabetic patients in the continuation phase may be due to an increased body weight and possible differences in hepatic induction. Further research is needed to determine the cause of increased tuberculosis treatment failure in diabetic patients. PMID: 20038625 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

  • SNP analysis of the Major Tripartite Multidrug Efflux Pump of Escherichia coli: Functional Conservation in Disparate Animal Reservoirs Despite Exposure to Antimicrobial Chemotherapy.

    Updated: 2009-12-27 23:00:00
    Authors: Elkins CA, Mullis LB, Lacher DW, Jung CM AcrAB-TolC imparts a strong intrinsic resistance phenotype to many clinically significant molecules in Escherichia coli. This complex is composed of a pump, AcrB, and a periplasmic protein, AcrA, that exports substrates through a common outer membrane porin, TolC. A sequence survey of the pump specific components, acrA and -B was conducted on three discrete animal reservoirs from rodent, bovine, and catfish. Although two of the reservoirs (bovine and catfish) were agrarian and reported antibiotic use (ceftiofur and oxytetracycline/Romet 30, respectively), the vast majority of structural polymorphisms were silent except for T104A (AcrA) and Q733R (AcrB) found in certain bovine-derived strains. Overall, the genes were well-conserved with ...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Applied and environmental microbiology: 2010 instructions to authors.

    Updated: 2009-12-25 12:38:06
    Authors: PMID: 20029058 [PubMed - in process] (Source: Applied and Environmental Microbiology)

  • Mathematical modeling of Kluyveromyces marxianus growth in solid-state fermentation using a packed-bed bioreactor.

    Updated: 2009-12-24 23:00:00
    Authors: Mazutti MA, Zabot G, Boni G, Skovronski A, de Oliveira D, Di Luccio M, Rodrigues MI, Maugeri F, Treichel H This work investigated the growth of Kluyveromyces marxianus NRRL Y-7571 in solid-state fermentation in a medium composed of sugarcane bagasse, molasses, corn steep liquor and soybean meal within a packed-bed bioreactor. Seven experimental runs were carried out to evaluate the effects of flow rate and inlet air temperature on the following microbial rates: cell mass production, total reducing sugar and oxygen consumption, carbon dioxide and ethanol production, metabolic heat and water generation. A mathematical model based on an artificial neural network was developed to predict the above-mentioned microbial rates as a function of the fermentation time, initial total redu...

  • Functional characterization of GDP-mannose pyrophosphorylase from Leptospira interrogans serovar Copenhageni.

    Updated: 2009-12-24 23:00:00
    Authors: Asención Diez MD, Demonte A, Giacomelli J, Garay S, Rodrígues D, Hofmann B, Hecht HJ, Guerrero SA, Iglesias AA Leptospira interrogans synthesizes a range of mannose-containing glycoconjugates relevant for its virulence. A prerequisite in the synthesis is the availability of the GDP-mannose, produced from mannose-1-phosphate and GTP in a reaction catalyzed by GDP-mannose pyrophosphorylase. The gene coding for a putative enzyme in L. interrogans was expressed in Escherichia coli BL21(DE3). The identity of this enzyme was confirmed by electrospray-mass spectroscopy, Edman sequencing and immunological assays. Gel filtration chromatography showed that the dimeric form of the enzyme is catalytically active and stable. The recombinant protein was characterized as a mannose-...

  • Generation and Characterization of Thymidine/D: -Alanine Auxotrophic Recombinant Lactococcus lactis subsp. lactis IL1403 Expressing BmpB.

    Updated: 2009-12-24 23:00:00
    Authors: Kim EB, Son JS, Zhang QK, Lee NK, Kim SH, Choi JH, Kang SK, Choi YJ Genetic engineering of Lactococcus lactis to produce a heterologous protein may cause potential risks to the environment despite the industrial usefulness of engineered strains. To reduce the risks, we generated three auxotrophic recombinant L. lactis subsp. lactis IL1403 strains expressing a heterologous protein, BmpB, using thyA- and alr-targeting integration vectors: ITD (thyA (-) alr (+) bmpB (+)), IAD (thyA (+) alr (-) bmpB (+)), and ITDAD (thyA (-) alr (-) bmpB (+)). After construction of integration vectors, each vector was introduced into IL1403 genome. Integration of BmpB expression cassette, deletion of thyA, and inactivation of alr were verified by using PCR reaction. All heterologous DNA fragments ...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Anti N1 Cross-Protecting Antibodies Against H5N1 Detected in H1N1 Infected People.

    Updated: 2009-12-24 23:00:00
    Authors: Frobert E, Bouscambert-Duchamp M, Escuret V, Mundweiler S, Barthélémy M, Morfin F, Valette M, Gerdil C, Lina B, Ferraris O The A(H5N1) influenza virus pandemic may be the result of avian H5N1 adapting to humans, leading to massive human to human transmission in a context of a lack of pre-existing immunity. As A(H1N1) and A(H5N1) share the same neuraminidase subtype, anti-N1 antibodies subsequent to H1N1 infections or vaccinations may confer some protection against A(H5N1). We analysed, by microneutralization assay, the A/Vietnam/1194/04 (H5N1) anti-N1 cross-protection acquired either during A/NewCaledonia/20/99 (H1N1) infection or vaccination. In cases with documented H1N1 infection, H5N1 cross-protection could be observed only in patients born between 1930 and 1950....

  • Risk factors for multidrug-resistant Pseudomonas aeruginosa acquisition. Impact of antibiotic use in a double case–control study

    Updated: 2009-12-24 18:57:53
    Content Type Journal ArticleCategory Brief ReportDOI 10.1007/s10096-009-0850-1Authors M. Montero, Autonomous University of Barcelona Dept. of Internal Medicine and Infectious Diseases, Hospital del Mar Passeig Marítim 25–29 08003 Barcelona SpainM. Sala, IMIM—Hospital del Mar, CIBER de Epidemiología y Salud Pública (CIBERESP) Health Services Evaluation and Clinical Epidemiology Service Barcelona SpainM. Riu, IMIM—Hospital del Mar, CIBER de Epidemiología y Salud Pública (CIBERESP) Health Services Evaluation and Clinical Epidemiology Service Barcelona SpainF. Belvis, IMIM—Hospital del Mar, CIBER de Epidemiología y Salud Pública (CIBERESP) Health Services Evaluation and Clinical Epidemiology Service Barcelona SpainM. Salvado, Laboratorio de Referencia de Catalunya Microbiolo...

  • Hijacking the host ubiquitin pathway: structural strategies of bacterial E3 ubiquitin ligases.

    Updated: 2009-12-23 23:00:00
    Authors: Hicks SW, Galán JE Ubiquitinylation of proteins is a critical mechanism in regulating numerous eukaryotic cellular processes including cell cycle progression, inflammatory response, and vesicular trafficking. Given the importance of ubiquitinylation, it is not surprising that several pathogenic bacteria have developed strategies to exploit various stages of the ubiquitin pathway for their own benefit. One such strategy is the delivery of bacterial 'effector' proteins into the host cell cytosol, which mimic the activities of components of the host ubiquitin pathway. Recent studies have highlighted a number of bacterial effectors that functionally mimic the activity of eukaryotic E3 ubiquitin ligases, including a novel structural class of bacterial E3 ligases that provides ...MedWorm Message:Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • The Toxoplasma Apicoplast Phosphate Translocator Links Cytosolic and Apicoplast Metabolism and Is Essential for Parasite Survival.

    Updated: 2009-12-23 23:00:00
    Authors: Brooks CF, Johnsen H, van Dooren GG, Muthalagi M, Lin SS, Bohne W, Fischer K, Striepen B Apicomplexa are unicellular eukaryotic pathogens that carry a vestigial algal endosymbiont, the apicoplast. The physiological function of the apicoplast and its integration into parasite metabolism remain poorly understood and at times controversial. We establish that the Toxoplasma apicoplast membrane-localized phosphate translocator (TgAPT) is an essential metabolic link between the endosymbiont and the parasite cytoplasm. TgAPT is required for fatty acid synthesis in the apicoplast, but this may not be its most critical function. Further analyses demonstrate that TgAPT also functions to supply the apicoplast with carbon skeletons for additional pathways and, indirectly, with energy and ...

  • Direct 16S rRNA gene sequencing of polymicrobial culture-negative samples with analysis of mixed chromatograms.

    Updated: 2009-12-23 23:00:00
    Authors: Hartmeyer GN, Justesen US Two cases, involving polymicrobial culture negative samples, were investigated by 16S sequencing, with analysis of mixed chromatograms. Fusobacterium necrophorum, Prevotella intermedia and Streptococcus constellatus were identified from pleural fluid in a patient with Lemierre's syndrome and Neisseria meningitidis and Escherichia coli from a petechia in a patient with meningococcal disease. PMID: 20035024 [PubMed - as supplied by publisher] (Source: Journal of Medical Microbiology)

  • Dynamics of extracellular release of Aspergillus fumigatus DNA and galactomannan during growth in blood and serum.

    Updated: 2009-12-23 23:00:00
    This study investigated A. fumigatus growth in vitro and in a murine model of IA in order to provide insights into the dynamics of extracellular DNA and GM release and their relevance to early diagnosis of IA. Following inoculation of whole blood with 20 A. fumigatus conidia ml-1, DNA that corresponded to the inoculum could be detected by PCR but GM was not detected in plasma separated from the blood sample, indicating that the fungus did not grow in whole blood. The quantities of DNA detected by PCR, and GM, were proportional to the amount of fungal biomass present in vitro. Fungal DNA could be detected in the sera of mice experimentally infected with A. fumigatus with maximum detection in cyclophosphamide treated mice. PMID: 20035025 [PubMed - as supplied by publisher] (Source: Journ...

  • Motility and flagellum involvement in Bacillus cereus biofilm formation.

    Updated: 2009-12-23 23:00:00
    Authors: Houry A, Briandet R, Aymerich S, Gohar M B. cereus is a food borne pathogen and a frequent contaminant of food industry plants. The persistence of this pathogen in various environments results from the formation of spores and of biofilms. To investigate the role of the B. cereus flagellar apparatus in biofilm formation, we built a non flagellated mutant and a flagellated but non motile mutant. Unexpectedly, we found that the flagellum presence decreased bacterium adhesion to glass surfaces. We hypothesize that this decrease is a consequence of the flagellum hindering a direct interaction between the bacterium cell wall and the surface. In contrast, in specific conditions, motility promotes biofilm formation. Our results suggest that motility could act on biofilm formation by t...

  • Cloning and expression analysis of the duplicated genes for carbon monoxide dehydrogenase of Mycobacterium sp. strain JC1 DSM 3803.

    Updated: 2009-12-23 23:00:00
    Authors: Song T, Park SW, Park SJ, Kim JH, Yu JY, Oh JI, Kim YM Carbon monoxide dehydrogenase (CO-DH) is an enzyme catalyzing the oxidation CO to carbon dioxide in Mycobacterium sp. strain JC1 DSM 3803. Cloning of the genes encoding CO-DH from the bacterium and sequencing of overlapping clones revealed the presence of duplicated sets of genes for three subunits of the enzyme, cutB1C1A1 and cutB2C2A2, in operons, and a cluster of genes encoding proteins that may be involved in CO metabolism, including a possible transcriptional regulator. Phylogenetic analysis based on the amino acid sequences of large subunits of CO-DH suggested that the CO-DHs of Mycobacterium sp. JC1 and other mycobacteria are distinct from those of other types of bacteria, which may reflect their unique enzymatic ac...

  • Growth-related changes in intracellular spermidine and its effect on efflux pump expression and quorum sensing in Burkholderia pseudomallei.

    Updated: 2009-12-23 23:00:00
    Authors: Chan YY, Chua KL The Burkholderia pseudomallei BpeAB-OprB RND pump effluxes aminoglycosides and macrolides antibiotics as well as acyl-homoserine lactone (AHLs) involved in quorum sensing. Expression of bpeA-lacZ was cell density-dependent and was inducible in the presence of these compounds. Intracellular levels of spermidine and N-acetylspermidine increased with cell density in wild-type B. pseudomallei KHW, but were always lower in the bpeAB pump mutant at all growth phases. Significance of changes in intracellular spermidine on efflux pump expression was demonstrated by the disruption of the binding of BpeR repressor protein to the bpeABoprB regulatory region in vitro in the presence of increasing spermidine concentration. This was supported by dose-dependent activation of...

  • Differentiation of Mycoplasma gallisepticum strains using PCR and High Resolution Melting Curve Analysis.

    Updated: 2009-12-23 23:00:00
    In this study, oligonucleotide primers were designed based on a region preceding the trinucleotide repeat of a member of the vlhA gene family and amplicons of 145-352 bp were generated from cultures of 10 different MG strains including the ts-11, F and 6/85 vaccine strains. High resolution melting (HRM) curve analysis of the resultant amplicons could differentiate all MG strains. Analysis of the nucleotide sequence of the amplicons from each strain revealed that each melting curve profile related to a unique DNA sequence. The HRM curve profiles (for ts-11) remained consistent after at least five passages under laboratory condition. PCR HRM curve analysis of 33 DNA extracts derived from respiratory swabs, or mycoplasma cultures grown from respiratory swabs, of ts-11 vaccinated commercial or...

  • Induction of Salmonella Pathogenicity Island 1 under different growth conditions can affect Salmonella-host cell interactions in vitro.

    Updated: 2009-12-23 23:00:00
    Authors: Ibarra JA, Knodler LA, Sturdevant DE, Virtaneva K, Carmody AB, Fischer ER, Porcella SF, Steele-Mortimer O Salmonella invade non-phagocytic cells by inducing massive actin rearrangements, resulting in membrane ruffle formation and phagocytosis of the bacteria. This process is mediated by a cohort of effector proteins translocated into the host cell by type III secretion system 1, which is encoded by genes in the Salmonella Pathogenicity Island 1 regulon. This network is precisely regulated and must be induced outside of host cells. In vitro invasive Salmonella are prepared by growth in synthetic media although the details vary. Here we show that, culture condition affects the frequency of Salmonella Pathogenicity Island 1 induced bacteria and therefore invasion efficiency and a...

  • Comparison of different mixed cultures for bio-hydrogen production from ground wheat starch by combined dark and light fermentation.

    Updated: 2009-12-23 23:00:00
    Authors: Ozmihci S, Kargi F Composition of the mixed culture was varied in combined dark-light fermentation of wheat powder starch in order to improve hydrogen gas formation rate and yield. Heat-treated anaerobic sludge and pure culture of Clostridium beijerinckii (DSMZ 791 ( T )) were combined with two different light fermentation bacteria of Rhodobacter sphaeroides (RS-NRRL and RS-RV) in order to select a more suitable mixture resulting in high hydrogen yield and formation rate. A combination of the anaerobic sludge and RS-NRRL yielded the highest cumulative hydrogen (CHF = 140 ml), the highest yield (0.36 mol H(2) mol(-1) glucose) and specific hydrogen formation rate (2.5 ml H(2) g(-1) biomass h(-1)). During dark fermentation (70 h) hydrogen was produced simultaneously by the dark a...

  • Fermentative production of self-toxic fungal secondary metabolites.

    Updated: 2009-12-23 23:00:00
    Authors: Singh MP, Leighton MM, Barbieri LR, Roll DM, Urbance SE, Hoshan L, McDonald LA Fungi are well known for their vast diversity of secondary metabolites that include many life-saving drugs and highly toxic mycotoxins. In general, fungal cultures producing such metabolites are immune to their toxic effects. However, some are known to produce self-toxic compounds that can pose production optimization challenges if the metabolites are needed in large amounts for chemical modification. One such culture, LV-2841, was identified as the lead for one of our exploratory projects. This culture was found to be a slow grower that produced trace amounts of a known metabolite, cercosporamide, under the standard flask fermentation conditions, and extensive medium optimization studies failed to ...

  • Linking species concepts to natural product discovery in the post-genomic era.

    Updated: 2009-12-23 23:00:00
    Authors: Jensen PR A widely accepted species concept for bacteria has yet to be established. As a result, species designations are inconsistently applied and tied to what can be considered arbitrary metrics. Increasing access to DNA sequence data and clear evidence that bacterial genomes are dynamic entities that include large numbers of horizontally acquired genes have added a new level of insight to the ongoing species concept debate. Despite uncertainties over how to apply species concepts to bacteria, there is clear evidence that sequence-based approaches can be used to resolve cohesive groups that maintain the properties of species. This cohesion is clearly evidenced in the genus Salinispora, where three species have been discerned despite very close relationships based on 16S rRN...

  • Engineering expression of the heavy metal transporter MerC in Saccharomyces cerevisiae for increased cadmium accumulation.

    Updated: 2009-12-23 23:00:00
    Authors: Kiyono M, Miyahara K, Sone Y, Pan-Hou H, Uraguchi S, Nakamura R, Sakabe K The merC gene from the Tn21-encoded mer operon has potential uses as a molecular tool for bioremediation. It was overexpressed as the fusion proteins MerC-Sso1p or MerC-Vam3p in Saccharomyces cerevisiae. Green fluorescent protein (GFP)-MerC-Sso1p fusion proteins located primarily in the plasma membrane, although some protein was detected in the endoplasmic reticulum. In contrast, GFP-MerC-Vam3p was expressed in the vacuolar membranes. These results suggest that yeast Sso1p and Vam3p are essential for targeting molecules to the plasma and vacuolar membranes, respectively. Significantly more cadmium ions were accumulated by yeast cells expressing MerC-Sso1p than with MerC-Vam3p or control cells. These resu...

  • Display of Candida antarctica lipase B on Pichia pastoris and its application to flavor ester synthesis.

    Updated: 2009-12-23 23:00:00
    Authors: Su GD, Huang DF, Han SY, Zheng SP, Lin Y Two alternative cell-surface display systems were developed in Pichia pastoris using the alpha-agglutinin and Flo1p (FS) anchor systems, respectively. Both the anchor cell wall proteins were obtained originally from Saccharomyces cerevisiae. Candida antarctica lipase B (CALB) was displayed functionally on the cell surface of P. pastoris using the anchor proteins alpha-agglutinin and FS. The activity of CALB displayed on P. pastoris was tenfold higher than that of S. cerevisiae. The hydrolytic and synthetic activities of CALB fused with alpha-agglutinin and FS anchored on P. pastoris were investigated. The hydrolytic activities of both lipases displayed on yeast cells surface were more than 200 U/g dry cell after 120 h of culture (200 an...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Diversity of Bacillus thuringiensis Isolated from Western Ghats of Tamil Nadu State, India.

    Updated: 2009-12-23 23:00:00
    Authors: Ramalakshmi A, Udayasuriyan V The Western Ghats of India is the one of the world's 10 "Hottest biodiversity hotspots" that runs along the western part of India through four states including Tamil Nadu. The only biodiversity reserve in the Western Ghats is the Nilgiri biosphere located in the Tamil Nadu state. In the present study, 525 soil samples were collected from all the 14 different divisions of the Western Ghats in Tamil Nadu state, India. A total of 316 new isolates of Bacillus thuringiensis (Bt) that produce parasporal crystalline inclusions were isolated from 525 soil samples. Seven different types of crystalline inclusions were observed in the 316 new isolates of Bt. Cuboidal inclusion was predominantly present in 26.9% of the Bt isolates when compared to other shape...

  • Comparative Evaluation of Five Culture Media with Triplex PCR Assay for Detection of Methicillin-Resistant Staphylococcus aureus.

    Updated: 2009-12-23 23:00:00
    In conclusion, all methods were comparable, but MSC-6 was the least expensive medium for MRSA screening. PMID: 20033170 [PubMed - as supplied by publisher] (Source: Current Microbiology)

  • Effects of Extremely Low-Frequency Electromagnetic Fields on Helicobacter pylori Biofilm.

    Updated: 2009-12-23 23:00:00
    Authors: Di Campli E, Di Bartolomeo S, Grande R, Di Giulio M, Cellini L The aim of this work was to investigate the effects of exposure to extremely low-frequency electromagnetic fields (ELF-EMF) both on biofilm formation and on mature biofilm of Helicobacter pylori. Bacterial cultures and 2-day-old biofilm of H. pylori ATCC 43629 were exposed to ELF-EMF (50 Hz frequency-1 mT intensity) for 2 days to assess their effect on the cell adhesion and on the mature biofilm detachment, respectively. All the exposed cultures and the respective sham exposed controls were studied for: the cell viability status, the cell morphological analysis, the biofilm mass measurement, the genotypic profile, and the luxS and amiA gene expression. The ELF-EMF acted on the bacterial population during the biofil...

  • Downregulation of protein kinase C-alpha enhances intracellular survival of Mycobacteria: role of PknG

    Updated: 2009-12-23 23:00:00
    Conclusions: All together, our data reveal a mechanism that shows substantial interdependence of PKCalpha with PknG, in sustaining mycobacterial infection. (Source: BMC Microbiology - Latest articles)

  • Contents / Sommaire

    Updated: 2009-12-23 15:05:51
    - Read article abstract for details. (Source: Canadian Journal of Microbiology)

  • Author Index / Index des auteurs

    Updated: 2009-12-23 15:05:51
    - Read article abstract for details. (Source: Canadian Journal of Microbiology)

  • To catch a killer. What can mycobacterial models teach us about Mycobacterium tuberculosis pathogenesis?

    Updated: 2009-12-22 23:00:00
    Authors: Shiloh MU, Digiuseppe Champion PA Mycobacterium tuberculosis is the causative agent of the global tuberculosis epidemic. To combat this successful human pathogen we need a better understanding of the basic biology of mycobacterial pathogenesis. The use of mycobacterial model systems has the potential to greatly facilitate our understanding of how M. tuberculosis causes disease. Recently, studies using mycobacterial models, including M. bovis BCG, M. marinum, and M. smegmatis have significantly contributed to understand M. tuberculosis. Specifically, there have been advances in genetic manipulation of M. tuberculosis using inducible promoters and recombineering that alleviate technical limitations in working with mycobacteria. Model systems have helped elucidate how secretion s...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Wolbachia: more than just a bug in insects genitals.

    Updated: 2009-12-22 23:00:00
    Authors: Saridaki A, Bourtzis K Research on the intracellular bacterial symbiont Wolbachia has grown on many levels, providing interesting insights on various aspects of the microbe's biology. Although data from fully sequenced genomes of different Wolbachia strains and from experimental studies of host-microbe interactions continue to arise, most of the molecular mechanisms employed by Wolbachia to manipulate the host cytoplasmic machinery and to ensure vertical transmission are yet to be discovered. Apart from the well-established role of Wolbachia in triggering reproductive alterations, a new fascinating aspect is emerging, related to the ecological benefits that the symbiont provides to the host. The mutualistic relationship of Wolbachia strains with disease vectors remains among t...

  • A genomic window into the virulence of Histophilus somni.

    Updated: 2009-12-22 23:00:00
    Authors: Sandal I, Inzana TJ Histophilus somni is an obligate inhabitant of the respiratory and genital mucosal surfaces of bovines and ovines. An individual strain can be a primary pathogen, an opportunistic pathogen, or a commensal, but can also move between these classifications if introduced into an appropriate site (e.g. the lungs) under conditions that favor bacterial persistence. H. somni is one of the bacterial agents responsible for bovine respiratory disease complex and can also cause a variety of systemic diseases in cattle and sheep. Isolates from disease sites, such as the lungs, heart, and brain, express a wide array of virulence factors (including biofilm formation) designed to evade host defense mechanisms. By contrast, some isolates from the healthy genital tract often...

  • Functional Analyses of Escherichia coli MutS-beta Clamp Interaction In Vitro and In Vivo.

    Updated: 2009-12-22 23:00:00
    Authors: Zhou Y, Li F, Chen Y, Bi L, Zhang XE Escherichia coli MutS is a highly conserved mismatch repair (MMR) protein that plays a key role in recognizing DNA mismatches and the early steps of MMR. Previous studies revealed an interaction between MutS and the replicative protein beta clamp, but it remains unclear whether the interaction functions during the process of MMR. In order to provide insight into the significance of this interaction, Far Western, Surface plasmon resonance and cell survival/mutagenesis assays were used to determine its possible influences on the in vitro and in vivo properties of MutS. The results show that a quintuple mutation of MutS residues 812-816 (MutS(betaC)), or single alanine substitution mutation of MutS residues M813 or L815 completely blocks bindi...

  • K30, H150, and H168 Are Essential Residues for Coordinating Pyridoxal 5'-Phosphate of O-Acetylserine Sulfhydrylase from Acidithiobacillus ferrooxidans.

    Updated: 2009-12-22 23:00:00
    Authors: Zheng C, Nie L, Qian L, Wang Z, Liu G, Liu J O-acetylserine sulfhydrylase (OASS) is a key enzyme involved in the pathway of the cysteine biosynthesis. The gene of OASS from Acidithiobacillus ferrooxidans ATCC 23270 was cloned and expressed in E. coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. Colors and UV-vis scanning results of the recombinant protein confirmed that it was a pyridoxal 5'-phosphate (PLP)-containing protein. Sequence alignment and site-directed mutation of the enzyme revealed that the cofactor PLP is covalently bound in Schiff base linkage with K30, as well as the two residues H150 and H168 were the crucial residues for PLP binding and stabilization. PMID: 20033172 [PubMed - as supplied by publisher] (Sou...

  • Note of appreciation / Note de reconnaissance

    Updated: 2009-12-22 15:08:02
    - Read article abstract for details. (Source: Canadian Journal of Microbiology)

  • The unraveling panoply of Francisella tularensis virulence attributes.

    Updated: 2009-12-21 23:00:00
    Authors: Meibom KL, Charbit A Francisella tularensis is a highly infectious Gram-negative bacterium causing the zoonotic disease tularemia. This facultative intracellular pathogen multiplies in vivo mainly inside macrophages, but has the capacity to infect and survive in many other cell types, including other phagocytic and nonphagocytic cells. In vitro, F. tularensis escapes rapidly from the phagosomal compartment and replicates in the cytoplasm of infected cells. An impressive number of novel genes related to F. tularensis pathogenesis have been identified recently. However, the information on biological functions still remains limited to a few of them. In this review, we will try to provide a comprehensive overview of the bacterial attributes, currently known-or suspected-to partici...

  • Achievements and perspectives to overcome the poor solvent resistance in acetone and butanol-producing microorganisms.

    Updated: 2009-12-21 23:00:00
    Authors: Ezeji T, Milne C, Price ND, Blaschek HP Anaerobic bacteria such as the solventogenic clostridia can ferment a wide range of carbon sources (e.g., glucose, galactose, cellobiose, mannose, xylose, and arabinose) to produce carboxylic acids (acetic and butyric) and solvents such as acetone, butanol, and ethanol (ABE). The fermentation process typically proceeds in two phases (acidogenic and solventogenic) in a batch mode. Poor solvent resistance by the solventogenic clostridia and other fermenting microorganisms is a major limiting factor in the profitability of ABE production by fermentation. The toxic effect of solvents, especially butanol, limits the concentration of these solvents in the fermentation broth, limiting solvent yields and adding to the cost of solvent recovery fr...

  • A standard quantitative method to measure acid tolerance of probiotic cells.

    Updated: 2009-12-21 23:00:00
    In conclusion, a standard quantitative method has been developed to measure the acid tolerance of probiotic cells. This could facilitate the selection of probiotic strains and processing technologies. PMID: 20033402 [PubMed - as supplied by publisher] (Source: Applied Microbiology and Biotechnology)

  • Fatty acid alkyl esters: perspectives for production of alternative biofuels.

    Updated: 2009-12-21 23:00:00
    This article points to the potential of different FAAE as alternative biofuels, e.g., by comparing their fuel properties. In addition to conventional production processes, this review presents natural and genetically engineered biological systems capable of in vivo FAAE synthesis. PMID: 20033403 [PubMed - as supplied by publisher] (Source: Applied Microbiology and Biotechnology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Early Viral Kinetics of Telbivudine and Entecavir: Results of a 12-week Randomized Exploratory Study in Patients With HBeAg-Positive Chronic Hepatitis B.

    Updated: 2009-12-21 23:00:00
    Authors: Suh DJ, Um SH, Herrmann E, Kim JH, Lee YS, Lee HJ, Lee MS, Lee YJ, Bao W, Lopez P, Lee HC, Avila C, Zeuzem S We characterized the early viral kinetics profiles of telbivudine and entecavir and the effects of these potent nucleoside analogs on hepatitis B virus DNA and alanine aminotransferase levels in adults with hepatitis B e antigen-positive compensated chronic hepatitis B. Forty-four patients were enrolled in this open-label, parallel-group, multicenter study and randomized to receive telbivudine or entecavir for 12 weeks. Reductions in hepatitis B virus DNA and alanine aminotransferase levels from baseline to weeks 2, 4, 8, and 12 were assessed. Viral kinetics parameters, including viral clearance per day, loss of infected cells per day, and efficiency of inhibition of vi...

  • Synergistic antimicrobial activity of folic acid antagonists and nucleoside analogs.

    Updated: 2009-12-21 23:00:00
    In conclusion, these data provide evidence that the in vitro antimicrobial activity of SXT in the presence of thymidine can be significantly improved by combination with a nucleoside analog. PMID: 20028816 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

  • Combined ramR mutation and presence of a Tn1721-associated tet(A) variant in a clinical isolate of Salmonella enterica Serovar Hadar resistant to Tigecycline.

    Updated: 2009-12-21 23:00:00
    Authors: Hentschke M, Christner M, Sobottka I, Aepfelbacher M, Rohde H A Salmonella enterica Serovar Hadar strain resistant to tigecycline (MIC 16 mug/ml) was isolated. Molecular characterization revealed the presence of a plasmid-borne tet(A) variant associated with Tn1721 mediating a rise of the MIC for tigecycline when transferred to Escherichia coli. Additionally, a truncating mutation in ramR was detected. Transformation with wildtype ramR but not with the mutated ramR lowered the MIC for tigecycline. Characterization of this Salmonella isolate thus implicates ramR in resistance to tigecycline. PMID: 20028818 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Mechanism of Hepatitis C Virus RNA Polymerase Inhibition with Dihydroxypyrimidines.

    Updated: 2009-12-21 23:00:00
    Authors: Powdrill MH, Deval J, Narjes F, De Francesco R, Götte M Here we studied biochemical mechanisms associated with inhibition and resistance to a 4,5-dihydroxypyrimidine carboxylate that inhibits the hepatitis C virus (HCV) RNA-dependent RNA polymerase NS5B. Based on the structure of the pharmacophore, it has been suggested that these compounds may act as pyrophosphate (PPi) mimics. We monitored nucleotide incorporation events during the elongation phase, and showed that the polymerase activity of wild type NS5B was inhibited by the dihydroxypyrimidine with an IC50 value of 0.73 muM. Enzymes with mutations G152E or P156L that confer resistance to this compound showed 4 to 5-fold increases in IC50 values. The inhibitor was competitive with respect to nucleotide incorporation. ...

  • Elucidation of Pharmacokinetic/Pharmacodynamic Determinant of Colistin Activity against Pseudomonas aeruginosa in Murine Thigh and Lung Infection Models.

    Updated: 2009-12-21 23:00:00
    Authors: Dudhani RV, Turnidge JD, Coulthard K, Milne RW, Rayner CR, Li J, Nation RL Colistin is increasingly used as last-line therapy against Gram-negative pathogens. The pharmacokinetic/pharmacodynamic (PK/PD) index best correlating with efficacy of colistin remains undefined. The PK/PD of colistin was studied in neutropenic mouse thigh and lung infection models against three strains of Pseudomonas aeruginosa. The pharmacokinetics of unbound colistin was determined from single-dose PK studies together with extensive plasma protein binding analyses. Dose fractionation studies were conducted over 24 h with a dose range of 5 - 160 mg/kg/day. Bacterial burden in thigh or lung was measured at 24 h after initiation of treatment. Relationships between antibacterial effect and measures of ex...

  • Probing the Antimalarial Mechanism of Artemisinin and OZ277 (Arterolane) With Non-peroxidic Isosteres and Nitroxyl Radicals.

    Updated: 2009-12-21 23:00:00
    Authors: Fügi MA, Wittlin S, Dong Y, Vennerstrom JL Peroxidic antimalarials such as the semisynthetic artemisinins are critically important in the treatment of drug-resistant malaria. Nevertheless, their peroxide bond-dependent mode of action is still not well understood. Using combination experiments with cultured Plasmodium falciparum, we investigated the interactions of the nitroxide radical spin trap, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and four of its analogs with artemisinin and the ozonide drug development candidate OZ277. The antagonism observed in combinations of artemisinin or OZ277 with the TEMPO analogs supports the hypothesis that formation of carbon-centered radicals is critical to the activity of these two antimalarial peroxides. The TEMPO analogs showed a ...

  • Detection of molecular markers of drug resistance in the 2009 pandemic influenza A (H1N1) viruses using pyrosequencing.

    Updated: 2009-12-21 23:00:00
    Conclusions: pyrosequencing is well suited for detection of drug resistance markers and signature mutations in the M and NA of the pandemic H1N1 influenza viruses. PMID: 20028826 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

  • Computer-assisted numerical analysis of colour-group data for dereplication of streptomycetes for bioprospecting and ecological purposes.

    Updated: 2009-12-21 23:00:00
    Authors: Antony-Babu S, Stach JE, Goodfellow M Large numbers of alkaliphilic streptomycetes isolated from a beach and dune sand system were dereplicated manually based on aerial spore mass, colony reverse and diffusible pigment colours formed on oatmeal agar, and on their capacity to produce melanin pigments on peptone-yeast extract-iron agar. The resultant data were converted to their respective red, blue and green shade intensities. The Euclidean distances between each of the colours were calculated by considering red, green and blue shade intensity values as X, Y and Z coordinates in three dimensional space. The clusters of isolates delineated in the dendrogram generated using the distances were found to match those obtained by manual colour-grouping of the isolates. A reasonable li...

  • Diversity and Community Structure of Archaea Inhabiting the Rhizoplane of Two Contrasting Plants from an Acidic Bog.

    Updated: 2009-12-21 23:00:00
    We examined the archaeal community inhabiting the rhizoplane of two contrasting vascular plants, Dulichium arundinaceum and Sarracenia purpurea, from an acidic bog in upstate NY. Multiple archaeal 16S rRNA gene libraries showed that methanogenic Archaea were dominant in the rhizoplane of both plants. In addition, the community structure (evenness) of the rhizoplane was found markedly different from the bulk peat. The archaeal community in peat from the same site has been found dominated by the E2 group, meanwhile the rhizoplane communities on both plants were co-dominated by Methanosarcinaceae (MS), rice cluster (RC)-I, and E2. Complementary T-RFLP analysis confirmed the difference between bulk peat and rhizoplane, and further characterized the dominance pattern of MS, RC-I, and E2. In the...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Microbial Fuel Cells and Microbial Ecology: Applications in Ruminant Health and Production Research.

    Updated: 2009-12-21 23:00:00
    Authors: Bretschger O, Osterstock JB, Pinchak WE, Ishii S, Nelson KE Microbial fuel cell (MFC) systems employ the catalytic activity of microbes to produce electricity from the oxidation of organic, and in some cases inorganic, substrates. MFC systems have been primarily explored for their use in bioremediation and bioenergy applications; however, these systems also offer a unique strategy for the cultivation of synergistic microbial communities. It has been hypothesized that the mechanism(s) of microbial electron transfer that enable electricity production in MFCs may be a cooperative strategy within mixed microbial consortia that is associated with, or is an alternative to, interspecies hydrogen (H(2)) transfer. Microbial fermentation processes and methanogenesis in ruminant animals ...

  • Erratum to: Local and remote tissue injury upon intestinal ischemia and reperfusion depends on the TLR/MyD88 signaling pathway

    Updated: 2009-12-21 22:00:04
    Content Type Journal ArticleCategory ErratumDOI 10.1007/s00430-009-0140-7Authors Tatiana Victoni, University of São Paulo Department of Pharmacology, Institute of Biomedical Sciences São Paulo 05508-900 BrazilFernando Rodrigues Coelho, University of São Paulo Department of Pharmacology, Institute of Biomedical Sciences São Paulo 05508-900 BrazilAlexandre Learth Soares, University of São Paulo Department of Pharmacology, Institute of Biomedical Sciences São Paulo 05508-900 BrazilAndressa de Freitas, University of São Paulo Department of Pharmacology, School of Medicine of Ribeirão Preto Ribeirão Preto 14049-900 BrazilThomas Secher, University and CNRS Molecular Immunology and Embryology UMR6218, Cedex 2 45071 Orléans FranceRodrigo Guabiraba, University and CNRS Molecular Immun...

  • Potential role for mucosally active vaccines against pneumococcal pneumonia.

    Updated: 2009-12-20 23:00:00
    Authors: Jambo KC, Sepako E, Heyderman RS, Gordon SB Pneumococcal pneumonia is a life-threatening disease with high mortality and morbidity among children under 5 years of age, the elderly and immunocompromised individuals worldwide. Protection against pneumococcal pneumonia relies on successful regulation of colonisation in the nasopharynx and a brisk alveolar macrophage-mediated immune response in the lung. Therefore, enhancing pulmonary mucosal immunity (which includes a combination of innate, humoral and cell-mediated immunity) through mucosal vaccination might be the key to prevention of pneumococcal infection. Current challenges include a lack of information in humans on mucosal immunity against pneumococci and a lack of suitable adjuvants for new vaccines. Data from mouse models...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Improved production of polygalacturonate lyase by combining a pH and online methanol control strategy in a two-stage induction phase with a shift in the transition phase.

    Updated: 2009-12-19 23:00:00
    Authors: Qureshi MS, Zhang D, Du G, Chen J Polygalacturonate lyase is a kind of enzyme that is abundantly used in the textile industry for cotton scouring. Previously, we reconstructed the polygalacturonate lyase gene in Pichia pastoris for the expression of this enzyme. To enhance the production of polygalacturonate lyase (PGL), a combined strategy was formulated by combining online methanol control and two-stage pH control strategies. For the two-stage pH control strategy during the growth phase, the pH was controlled at 5.5, and in the induction phase different pH levels were investigated for the optimum enzyme production. During the online methanol control strategy, the different levels of methanol (v/v) were investigated for the best enzyme production at pH 5.5. These two strategi...

  • A Transcriptional "Scream" Early Response of E. coli Prey to Predatory Invasion by Bdellovibrio.

    Updated: 2009-12-19 23:00:00
    Authors: Lambert C, Ivanov P, Sockett RE We have transcriptionally profiled the genes differentially expressed in E. coli prey cells when predatorily attacked by Bdellovibrio bacteriovorus just prior to prey cell killing. This is a brief, approximately 20-25 min period when the prey cell is still alive but contains a Bdellovibrio cell in its periplasm or attached to and penetrating its outer membrane. Total RNA was harvested and labelled 15 min after initiating a semi-synchronous infection with an excess of Bdellovibrio preying upon E. coli and hybridised to a macroarray spotted with all predicted ORFs of E. coli. SAM analysis and t-tests were performed on the resulting data and 126 E. coli genes were found to be significantly differentially regulated by the prey upon attack by Bdellov...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Microarray analysis of p-anisaldehyde-induced transcriptome of Saccharomyces cerevisiae.

    Updated: 2009-12-18 23:00:00
    Authors: Yu L, Guo N, Yang Y, Wu X, Meng R, Fan J, Ge F, Wang X, Liu J, Deng X p-Anisaldehyde (4-methoxybenzaldehyde), an extract from Pimpinella anisum L. seeds, is a potential novel preservative. To reveal the possible action mechanism of p-anisaldehyde against microorganisms, yeast-based commercial oligonucleotide microarrays were used to analyze the genome-wide transcriptional changes in response to p-anisaldehyde. Quantitative real-time RT-PCR was performed for selected genes to verify the microarray results. We interpreted our microarray data with the clustering tool, T-profiler. Analysis of microarray data revealed that p-anisaldehyde induced the expression of genes related to sulphur assimilation, aromatic aldehydes metabolism, and secondary metabolism, which demonstrated that ...

  • Spore-to-spore agar culture of the myxomycete Physarum globuliferum.

    Updated: 2009-12-18 23:00:00
    Authors: Liu P, Wang Q, Li Y The ontogeny of the myxomycete Physarum globuliferum was observed on corn meal agar and hanging drop cultures without adding sterile oat flakes, bacteria or other microorganisms. Its complete life cycle including spore germination, myxamoebae, swarm cells, plasmodial development, and maturity of fructifications was demonstrated. Details of spore-to-spore development are described and illustrated. PMID: 20024530 [PubMed - as supplied by publisher] (Source: Archives of Microbiology)

  • Synthesis and production of polyhydroxyalkanoates by halophiles: current potential and future prospects.

    Updated: 2009-12-18 23:00:00
    Authors: Quillaguamán J, Guzmán H, Van-Thuoc D, Hatti-Kaul R Biodegradable materials with plastic or elastomeric properties are in great demand for a variety of applications. Polyhydroxyalkanoates (PHAs), polyesters synthesized by microorganisms, possess such desired features. Industrial production of PHAs is currently achieved using recombinant Escherichia coli. Nevertheless, recent research on halophiles, salt requiring microorganisms, has shown a remarkable potential for biotechnological production of PHAs. The halophilic archaeon Haloferax mediterranei accumulates a co-polymer, i.e., poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in large amounts using glucose, starch, and hydrolyzed whey as carbon sources. Chemical composition and molecular weight of PHAs produced by H. me...

  • Production of pig liver esterase in batch fermentation of E. coli Origami.

    Updated: 2009-12-18 23:00:00
    Authors: Brüsehaber E, Schwiebs A, Schmidt M, Böttcher D, Bornscheuer UT The establishment of a fermentation process for the production of pig liver esterase (PLE) in high yields is necessary for industrial applications. In our previous studies, we reported the recombinant expression of PLE in Escherichia coli Origami (DE3) in shake flask. Only a coexpression with chaperones GroEL/ES allowed the production of soluble and active enzyme. The optimization of the cultivation conditions, such as temperature, inducer concentrations, or media compositions to increase enzyme yield in a fermentation process is described here. Using fed-batch fermentation cell densities up to OD = 50 were obtained, but almost no active enzyme was expressed. Only batch fermentation was found suitable fo...

  • Rapid solubilization of insoluble phosphate by a novel environmental stress-tolerant Burkholderia vietnamiensis M6 isolated from ginseng rhizospheric soil.

    Updated: 2009-12-18 23:00:00
    Authors: Park KH, Lee OM, Jung HI, Jeong JH, Jeon YD, Hwang DY, Lee CY, Son HJ We isolated and characterized novel insoluble phosphate (P)-solubilizing bacteria tolerant to environmental factors like high salt, low and high pHs, and low temperature. A bacterium M6 was isolated from a ginseng rhizospheric soil and confirmed to belong to Burkholderia vietnamiensis by BIOLOG system and 16S rRNA gene analysis. The optimal cultural conditions for the solubilization of P were 2.5% (w/v) glucose, 0.015% (w/v) urea, and 0.4% (w/v) MgCl(2).6H(2)O along with initial pH 7.0 at 35 degrees C. High-performance liquid chromatography analysis showed that B. vietnamiensis M6 produced gluconic and 2-ketogluconic acids. During the culture, the pH was reduced with increase in gluconic acid concentration a...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Method to detect only viable cells in microbial ecology.

    Updated: 2009-12-18 23:00:00
    Authors: Luo JF, Lin WT, Guo Y Propidium monoazide can limit the analysis of microbial communities derived from genetic fingerprints to viable cells with intact cell membranes. However, PMA treatment cannot completely suppress polymerase chain reaction (PCR) amplification when the targeted gene is too short. PMA treatment in combination with two-step nested PCR was designed to overcome this problem. Four experiments were performed to determine the limitation of PMA treatment and to evaluate the suitability of the method by applying the following samples: (1) pure cultures of Escherichia coli O157:H7, Enterobacter aerogenes, and Alcaligenes faecalis; (2) pond water samples spiked with heat-killed E. coli O157:H7 and E. aerogenes; (3) anaerobic sludge samples exposed to increasing heat s...

  • Loss of phosphomannomutase activity enhances actinorhodin production in Streptomyces coelicolor.

    Updated: 2009-12-18 23:00:00
    Authors: Yang YH, Song E, Park SH, Kim JN, Lee K, Kim E, Kim YG, Kim BG Phosphomannomutase (ManB), whose main function is the conversion of mannose-6-phosphate to mannose-1-phosphate, is involved in biosynthesis of GDP-mannose for numerous processes such as synthesis of structural carbohydrates, production of alginates and ascorbic acid, and post-translational modification of proteins in prokaryotes and eukaryotes. ManB isolated from Streptomyces coelicolor was shown to have both phosphomannomutase and phosphoglucomutase activities. Deletion of manB in S. coelicolor caused a dramatic increase in actinorhodin (ACT) production in the low-glucose Difco nutrient (DN) medium, whereas the wild-type strain did not produce ACT on this medium. Experiments involving complementation of the manB d...

  • New applications and performance of bioelectrochemical systems.

    Updated: 2009-12-18 23:00:00
    Authors: Hamelers HV, Ter Heijne A, Sleutels TH, Jeremiasse AW, Strik DP, Buisman CJ Bioelectrochemical systems (BESs) are emerging technologies which use microorganisms to catalyze the reactions at the anode and/or cathode. BES research is advancing rapidly, and a whole range of applications using different electron donors and acceptors has already been developed. In this mini review, we focus on technological aspects of the expanding application of BESs. We will analyze the anode and cathode half-reactions in terms of their standard and actual potential and report the overpotentials of these half-reactions by comparing the reported potentials with their theoretical potentials. When combining anodes with cathodes in a BES, new bottlenecks and opportunities arise. For application of BE...

  • Diversity and Community Structure of Archaea in Deep Subsurface Sediments from the Tropical Western Pacific.

    Updated: 2009-12-18 23:00:00
    Authors: Zhang W, Saren G, Li T, Yu X, Zhang L Archaeal 16S rRNA gene clone libraries using PCR amplicons from eight different layers of the MD06-3051 core were obtained from the tropical Western Pacific sediments. A total of 768 clones were randomly selected, and 264 representative clones were sequenced by restriction fragment length polymorphism. Finally, 719 valid clones and 104 operational taxonomic units were identified after chimera-check and >/=97% similarity analysis. The phylogenetic analysis of 16S rDNA sequences obtained from sediment samples were very diverse and showed stratification with depth. Majority of the members were most closely related to uncultivated groups and physiologically uncharacterized assemblages. All phylotypes were affiliated with Crenarchaeota (76%)...

  • CMEIAS Color Segmentation: An Improved Computing Technology to Process Color Images for Quantitative Microbial Ecology Studies at Single-Cell Resolution.

    Updated: 2009-12-18 23:00:00
    Authors: Gross CA, Reddy CK, Dazzo FB Quantitative microscopy and digital image analysis are underutilized in microbial ecology largely because of the laborious task to segment foreground object pixels from background, especially in complex color micrographs of environmental samples. In this paper, we describe an improved computing technology developed to alleviate this limitation. The system's uniqueness is its ability to edit digital images accurately when presented with the difficult yet commonplace challenge of removing background pixels whose three-dimensional color space overlaps the range that defines foreground objects. Image segmentation is accomplished by utilizing algorithms that address color and spatial relationships of user-selected foreground object pixels. Performance o...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Survival of native Pseudomonas in soil and wheat rhizosphere and antagonist activity against plant pathogenic fungi.

    Updated: 2009-12-18 23:00:00
    Authors: Fischer SE, Jofré EC, Cordero PV, Gutiérrez Mañero FJ, Mori GB Survival of Pseudomonas sp. SF4c and Pseudomonas sp. SF10b (two plant-growth-promoting bacteria isolated from wheat rhizosphere) was investigated in microcosms. Spontaneous rifampicin-resistant mutants derived from these strains (showing both growth rate and viability comparable to the wild-strains) were used to monitor the strains in bulk soil and wheat rhizosphere. Studies were carried out for 60 days in pots containing non-sterile fertilized or non-fertilized soil. The number of viable cells of both mutant strains declined during the first days but then became established in the wheat rhizosphere at an appropriate cell density in both kinds of soil. Survival of the strains was better in the rhizos...

  • Chapter 1: Variation in form and function the helix-turn-helix regulators of the GntR superfamily.

    Updated: 2009-12-18 03:20:03
    Authors: Hoskisson PA, Rigali S One of the most abundant and widely distributed groups of Helix-turn-helix (HTH) transcription factors is the metabolite-responsive GntR family of regulators (>8500 members in the Pfam database; Jan 2009). These proteins contain a DNA-binding HTH domain at the N terminus of the protein and an effector-binding and/or oligomerisation domain at the C terminus, where upon on binding an effector molecule, a conformational change occurs in the protein which influences the DNA-binding properties of the regulator resulting in repression or activation of transcription. This review summarises what we know about the distribution, structure, function and classification of these regulators and suggests that they may have a future role in biotechnology. PMID: 1...

  • Chapter 2: Biogenesis of the cell wall and other glycoconjugates of Mycobacterium tuberculosis.

    Updated: 2009-12-18 03:20:03
    Authors: Kaur D, Guerin ME, Skovierová H, Brennan PJ, Jackson M The re-emergence of tuberculosis in its present-day manifestations - single, multiple and extensive drug-resistant forms and as HIV-TB coinfections - has resulted in renewed research on fundamental questions such as the nature of the organism itself, Mycobacterium tuberculosis, the molecular basis of its pathogenesis, definition of the immunological response in animal models and humans, and development of new intervention strategies such as vaccines and drugs. Foremost among these developments has been the precise chemical definition of the complex and distinctive cell wall of M. tuberculosis, elucidation of the relevant pathways and underlying genetics responsible for the synthesis of the hallmark moieties of the tub...

  • Chapter 3: Antimicrobial properties of hydroxyxanthenes.

    Updated: 2009-12-18 03:20:03
    Authors: Waite JG, Yousef AE Hydroxyxanthenes are commonly used as dyestuffs in the food, cosmetics, and textile industries. These compounds also have medical applications due to their unique staining and fluorescent properties. The halogenated hydroxyxanthenes exhibit antimicrobial properties that may be useful for reducing or eliminating bacterial pathogens from a variety of environments, including drinking water and food products. Antimicrobial characteristics of Eosin, Erythrosine, Phloxine, and Rose Bengal have been known for many years, but their application as antimicrobial agents has been limited primarily to selective agents in microbiological growth media. The primary mechanism of bacterial inactivation by hydroxyxanthenes is photooxidation. When halogenated hydroxyxanthenes ...

  • Chapter 4: In vitro biofilm models: an overview.

    Updated: 2009-12-18 03:20:03
    Authors: McBain AJ Observing naturally occurring biofilms in situ or ex situ has revealed the wide distribution of sessile microbial communities. The ubiquity, variety and complexity of biofilms is now widely accepted by microbiologists. While they are associated with many beneficial functions such as nutrient cycling, bioremediation and colonization resistance, adverse effects including recalcitrance, their involvement in industrial fouling, contamination and infection have made biofilms a priority research topic. We know that most biofilms, other than within certain infections and laboratory flasks, are composed of multiple species and that there is arguably no unifying biofilm architecture. Biofilms do however share certain properties including the presence of gradients of nutrients...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Chapter 5: Zones of inhibition? The transfer of information relating to penicillin in Europe during World War II.

    Updated: 2009-12-18 03:20:03
    Authors: Shama G Alexander Fleming published his first description of penicillin in 1929, but the journal articles that were to propel penicillin from its relative obscurity were those of Howard Florey and his co-workers at Oxford University. These were published in The Lancet in the early years of World War II and although wartime conditions restricted the flow of information on penicillin throughout Europe, they never succeeded in shutting it off altogether. In Germany an information-gathering initiative was established in the early phases of the war to systematically copy and distribute British and American scientific articles. A similar, though less well-resourced, operation was permitted to function in Occupied France. Both these operations were to yield up information on penicill...

  • Chapter 6: The genomes of lager yeasts.

    Updated: 2009-12-18 03:20:03
    Authors: Bond U Yeasts used in the production of lagers belong to the genus Saccharomyces pastorianus. Species within this genus arose from a natural hybridization event between two yeast species that appear to be closely related to Saccharomyces cerevisiae and Saccharomyces bayanus. The resultant hybrids contain complex allopolyploid genomes and retain genetic characteristics of both parental species. Recent genome analysis using both whole genome sequencing and competitive genomic hybridization techniques has revealed the underlying composition of lager yeasts genomes. There appear to be at least 36 unique chromosomes, many of which are lager specific, resulting from recombination events between the homeologous parental chromosomes. The recombination events are limited to a defined s...

  • A broadening world of bacterial small RNAs.

    Updated: 2009-12-17 23:00:00
    Authors: Liu JM, Camilli A The ubiquity of small RNAs (sRNAs) in bacteria is now well established. These transcripts are the members of regulatory circuits involved in diverse processes ranging from stress adaptation to virulence to metabolism. Recent large-scale searches suggest that there exist many times more sRNAs than previously predicted even in the best studied bacterial transcriptomes. On the basis of these and other recent findings of regulatory sRNAs that do not function in a 'classical' manner, we propose that the working definition of sRNAs be broadened. PMID: 20022798 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)

  • Finding a way to the nucleus.

    Updated: 2009-12-17 23:00:00
    Authors: Gelvin SB Agrobacterium species transfer single-strand DNA and virulence effector proteins to plants. To understand how Agrobacterium achieves interkingdom horizontal gene transfer, scientists have investigated how the interaction of bacterial effector proteins with host proteins directs T-DNA to the plant nucleus. VirE2, a single-strand DNA binding protein, likely plays a key role in T-DNA nuclear targeting. However, subcellular trafficking of VirE2 remains controversial, with reports of both cytoplasmic and nuclear localization. The recent discovery that phosphorylation of the VirE2 interacting protein VIP1 modulates both nuclear targeting and transformation may provide a solution to this conundrum. Novel experimental systems that allow tracking of VirE2 as it exits Agrobact...

  • Identification of prophage gene z2389 in Escherichia coli EDL933 encoding a DNA cytosine methyltransferase for full protection of NotI sites.

    Updated: 2009-12-17 23:00:00
    Authors: Chiou CS, Li HY, Tung SK, Chen CY, Teng CH, Shu JC, Tseng JT, Hsu CY, Chen CC Pulsed-field gel electrophoresis (PFGE) analysis revealed that the genomes of some pathogenic Escherichia coli O157:H7 strains, including EDL933, were resistant to NotI digestion. An amino acid sequence comparison suggested that the z2389 gene carried on prophage CP-933R in strain EDL933 is likely to encode a C(5)-cytosine methyltransferase. The z2389-equivalent gene was found in the NotI-resistant strains tested, but it was not detected in the NotI-susceptible strains. PFGE analysis of the wild-type EDL933 strain and of a z2389 null mutant revealed that z2389 was associated with full genome protection against NotI digestion and partial protection against EagI digestion. In vitro methylation experime...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Studying the dynamics of flagella in multicellular communities of Escherichia coli using biarsenical dyes.

    Updated: 2009-12-17 23:00:00
    Authors: Copeland MF, Flickinger ST, Tuson HH, Weibel DB This manuscript describes a new approach for labeling intact flagella using the biarsenical dyes FlAsH and ReAsH and imaging their spatial and temporal dynamics on live Escherichia coli cells in swarming communities of bacteria using epifluorescence microscopy. Using this approach we observe that: (1) bundles of flagella on swarmer cells remain cohesive during frequent collisions with neighboring cells; (2) flagella on non-motile swarmer cells at the leading edge of the colony protrude in the direction of the uncolonized agar surface and are actively rotated in a thin layer of fluid that extends outward from the colony; and (3) flagella form transient interactions with the flagella of other swarmer cells that are in close proximi...

  • Milk protein fragments induce the biosynthesis of macedocin, the lantibiotic produced by Streptococcus macedonicus ACA-DC 198.

    Updated: 2009-12-17 23:00:00
    Authors: Georgalaki M, Papadelli M, Chassioti E, Anastasiou R, Aktypis A, De Vuyst L, Van Driessche G, Devreese B, Tsakalidou E The aim of the present work was to study the mode of induction of biosynthesis of macedocin, the lantibiotic produced by Streptococcus macedonicus ACA-DC 198. Macedocin was produced when the strain was grown in milk but not in MRS or M17 broth. No auto-induction mechanism was observed. Production did not depend on the presence of lactose or galactose in the culture medium, or on a co-culture of the producer strain with macedocin-sensitive or macedocin-resistant strains. Induction seemed to depend on the presence of one or more heat stable protein components produced when S. macedonicus ACA-DC 198 was grown in milk. Partial purification of the induction factor ...

  • Correlation between environmental factors and prevalence of V. parahaemolyticus in oysters harvested in the southern coastal area of Sao Paulo State, Brazil.

    Updated: 2009-12-17 23:00:00
    Authors: Sobrinho PD, Destro MT, Franco BD, Landgraf M Vibrio parahaemolyticus was investigated in 123 oyster samples collected in an estuary in the southern coast of Sao Paulo State, Brazil. 99.2 % of the samples were positive, densities ranging from <3 to 10(5) MPN/g. Densities correlated significantly with water temperature (r = 0.48, P<0.001), but not with salinity (r = -0.09, P = 0.34). The effect of harvest site on counts was not significant (P>0.05). These data provide information for the assessment of exposure of V. parahaemolyticus in oysters at harvest level. PMID: 20023076 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)

  • Novel and Highly Diverse Acid-Tolerant Denitrifiers are Associated with N2O Fluxes of an Acidic Fen.

    Updated: 2009-12-17 23:00:00
    Authors: Palmer K, Drake HL, Horn MA Wetlands are sources of denitrification-derived nitrous oxide (N2O). Thus, the denitrifier community of an N2O-emitting fen (pH 4.7 to 5.2) was investigated. N2O was produced and consumed to sub-atmospheric concentrations in unsupplemented anoxic soil microcosms. Total cell counts and most probable numbers of denitrifiers approximated 10(11) cells.g(-1)DW and 10(8) cells.g(-1)DW, respectively, in both 0 to 10 cm and 30 to 40 cm depths. Despite this uniformity, depth-related vmax values for denitrification in anoxic microcosms ranged from 1 to 24 and -19 to -105 nmol N2O h(-1).g(-1)DW, with maximal values occurring in the upper soil layers. Denitrification was enhanced by substrates that might be formed via fermentation in anoxic microzones of soil. ...

  • Metabolic differentiation in biofilms as indicated by carbon dioxide production rates.

    Updated: 2009-12-17 23:00:00
    Authors: Bester E, Kroukamp O, Wolfaardt GM, Boonzaaier L, Liss SN The measurement of carbon dioxide production rates as an indication of metabolic activity was applied to study biofilm development and response of Pseudomonas sp. biofilms to an environmental disturbance in the form of a moving air-liquid interface (i.e. shear). A differential response in biofilm cohesivity was observed after the bubble perturbation, and operationally defined as either the shear-susceptible, or the non-shear-susceptible base biofilm layers. Confocal laser scanning microscopy and image analysis showed a significant reduction in biofilm thickness and biomass after the removal of the shear-susceptible biofilm layer, as well as notable changes in roughness coefficient and surface-to-biovolume ratio. These c...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

  • Archaeal diversity and distribution along thermal and geochemical gradients in hydrothermal sediments at the Yonaguni Knoll IV, the Southern Okinawa Trough.

    Updated: 2009-12-17 23:00:00
    In this study, phylogenetic diversity and distribution profiles of the archaeal genes encoding small subunit (SSU) rRNA, methyl CoA reductase subunit A and ammonia monooxygenase large subunit were characterized in hydrothermally influenced sediments at the Yonaguni Knoll IV hydrothermal field in the Southern Okinawa Trough. Sediment cores were collected at distances of 0.5, 2 or 5 m from a vent emission (90 degrees C). A moderate temperature gradient extends both horizontally and vertically (5 to 69 degrees C) indicating the existence of moderate mixing between the hydrothermal fluid and the ambient sediment pore-water. The mixing of reductive hot hydrothermal fluid and cold ambient sediment pore-water establishes a wide spectrum of physical and chemical conditions in the microbial habitat...

  • Inactivation of Adenoviruses, Enteroviruses, and Murine Norovirus in Water by Free Chlorine and Monochloramine.

    Updated: 2009-12-17 23:00:00
    Authors: Cromeans TL, Kahler AM, Hill VR Inactivation of infectious viruses during drinking water treatment is usually achieved with free chlorine. Many drinking water utilities in the United States now use monochloramine as a secondary disinfectant to minimize disinfectant byproduct formation and biofilm growth. The inactivation of adenoviruses 2, 40 and 41 (HAdV2, HAdV40 and HAdV41), coxsackieviruses B3 and B5 (CVB3 and CVB5), echoviruses 1 and 11 (E1 and E11) and murine norovirus (MNV), are compared in this study. Experiments were performed with 0.2 mg/L free chlorine or 1 mg/L monochloramine at pH 7 and pH 8 in buffered reagent grade water (RGW) at 5 degrees C. Ct values for 2-4-log10 (99-99.99%) reductions in viral titers were calculated using the Efficiency Factor Hom (EFH) model...

  • A mariner-Based Transposon System for In Vivo Random Mutagenesis of Clostridium difficile.

    Updated: 2009-12-17 23:00:00
    In this study, we developed a novel mariner-based transposon system for in vivo random mutagenesis of C. difficile R20291, the BI/NAP1/027 epidemic strain at the centre of the CDI outbreaks in Stoke Mandeville, UK in 2003-4 and 2004-5. Transposition occurred at a frequency of 4.5(+/-0.4) x 10(-4) per cell to give stable insertions at random genomic loci, which were only defined by the nucleotide sequence 'TA'. Furthermore, mutants with just a single transposon insertion were generated in an overwhelming majority (98.3% in this study). Phenotypic screening of a C. difficile R20291 random mutant library yielded a sporulation/germination defective clone with an insertion in the germination specific protease gene cspBA, and an auxotroph with an insertion in the pyrimidine biosynthesis gene pyr...

  • A type II diacylglycerol acyltransferase from Claviceps purpurea with substrate preference towards ricinoleic acid, a hydroxyl fatty acid of industrial importance.

    Updated: 2009-12-17 23:00:00
    Authors: Mavraganis I, Meesapyodsuk D, Vrinten P, Smith M, Qiu X Claviceps purpurea, the fungal pathogen that causes the cereal disease ergot, produces glycerides that contain high levels of ricinoleic acid ((R)-12-hydroxyoctadec-cis-9-enoic acid) in its sclerotia. Recently, a fatty acid hydroxylase (CpFAH) involved in the biosynthesis of ricinoleic acid was identified from this fungus (Plant Physiology, 147: 1325-1333, 2008). Here, we describe the cloning and biochemical characterization of a C. purpurea type II diacylglycerol acyltransferase (CpDGAT2) involved in the assembly of ricinoleic acid into triglycerides. The CpDGAT2 gene was cloned by degenerate RT-PCR (Reverse transcription polymerase chain reaction). Expression of this gene restored the in vivo synthesis of triacylglycero...

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