• The case for the defense: Plants versus Pseudomonas syringae.

    Updated: 2010-03-11 19:29:18
    The case for the defense: Plants versus Pseudomonas syringae. Microbes Infect. 2010 Mar 6; Authors: Gimenez-Ibanez S, Rathjen JP Incredible progress has been made over the last 20 years in understanding the components and mechanisms governing plant innate immunity. The most important discoveries concern pathogen recognition mechanisms, which divide perception of conserved elicitors at the cell periphery, and recognition of variable elicitors within the host cytoplasm. The underlying mechanisms of immunity post elicitation are complex and poorly defined. This review highlights emergent themes in plant-microbe interactions with a particular focus on the plant immune responses against infection by the bacterium Pseudomonas syringae. PMID: 20214999 [PubMed - as supplied by publisher]

  • Emerging multi-drug resistant Mycobacterium tuberculosis strains of the Beijing genotype circulating in Russia express a pattern of biological properties associated with enhanced virulence.

    Updated: 2010-03-11 19:29:17
    . . : Warning The NCBI web site requires JavaScript to function . more . Resources All Resources Literature Bookshelf Journals Database MeSH Database PubMed PubMed Central All Literature Resources… DNA RNA BankIt BLAST BLAST Stand-alone GenBank Genome Workbench Influenza Virus Nucleotide Database PopSet Reference Sequence RefSeq Sequence Read Archive SRA Trace Archive All DNA RNA Resources… Proteins BLAST BLAST Stand-alone BLAST Link BLink CD-Search GenBank ProSplign Protein Protein Clusters Reference Sequence RefSeq All Proteins Resources… Sequence Analysis BLAST BLAST Stand-alone BLAST Link BLink GenBank Genome Workbench Influenza Virus Primer-BLAST ProSplign Splign All Sequence Analysis Resources… Genes Expression GenBank Gene Gene Expression Omnibus GEO Datasets Gene Expression Omnibus GEO Profiles Genome Workbench HomoloGene Map Viewer Online Mendelian Inheritance in Man OMIM UniGene All Genes Expression Resources… Genomes Maps Database of Genomic Structural Variation dbVar Genome Genome Project Genome Workbench Influenza Virus Map Viewer Nucleotide Database PopSet ProSplign Sequence Read Archive SRA Splign Trace Archive UniSTS All Genomes Maps Resources… Domains

  • Requirement of NMB0065 for connecting assembly and export of sialic acid capsular polysaccharides in Neisseria meningitidis.

    Updated: 2010-03-11 19:29:16
    . . : Warning The NCBI web site requires JavaScript to function . more . Resources All Resources Literature Bookshelf Journals Database MeSH Database PubMed PubMed Central All Literature Resources… DNA RNA BankIt BLAST BLAST Stand-alone GenBank Genome Workbench Influenza Virus Nucleotide Database PopSet Reference Sequence RefSeq Sequence Read Archive SRA Trace Archive All DNA RNA Resources… Proteins BLAST BLAST Stand-alone BLAST Link BLink CD-Search GenBank ProSplign Protein Protein Clusters Reference Sequence RefSeq All Proteins Resources… Sequence Analysis BLAST BLAST Stand-alone BLAST Link BLink GenBank Genome Workbench Influenza Virus Primer-BLAST ProSplign Splign All Sequence Analysis Resources… Genes Expression GenBank Gene Gene Expression Omnibus GEO Datasets Gene Expression Omnibus GEO Profiles Genome Workbench HomoloGene Map Viewer Online Mendelian Inheritance in Man OMIM UniGene All Genes Expression Resources… Genomes Maps Database of Genomic Structural Variation dbVar Genome Genome Project Genome Workbench Influenza Virus Map Viewer Nucleotide Database PopSet ProSplign Sequence Read Archive SRA Splign Trace Archive UniSTS All Genomes Maps Resources… Domains

  • Validation of multiplex PCR for simultaneous detection, identification of methicilin resistant

    Updated: 2010-03-09 16:15:51
    Jindal NIndian Journal of Medical Microbiology 2010 28(1):82-83 (Source: Indian Journal of Medical Microbiology)

  • Emergence of optochin resistance among

    Updated: 2010-03-09 16:15:51
    Kacou-N'douba A, Okpo S C, Ekaza E, Pakora A, Koffi S, Dosso MIndian Journal of Medical Microbiology 2010 28(1):80-81 (Source: Indian Journal of Medical Microbiology)

  • Differentiation of clinical

    Updated: 2010-03-09 16:15:51
    Conclusion: The gyrB PCR-RFLP using the endonuclease Rsa1 can be used to differentiate M. tuberculosis from M. bovis in clinical isolates. (Source: Indian Journal of Medical Microbiology)

  • Genetic factors that influence moenomycin production in streptomycetes.

    Updated: 2010-03-05 23:00:00
    Authors: Makitrynskyy R, Rebets Y, Ostash B, Zaburannyi N, Rabyk M, Walker S, Fedorenko V Moenomycin, a natural phosphoglycolipid product that has a long history of use in animal nutrition, is currently considered an attractive starting point for the development of novel antibiotics. We recently reconstituted the biosynthesis of this natural product in a heterologous host, Streptomyces lividans TK24, but production levels were too low to be useful. We have examined several other streptomycetes strains as hosts and have also explored the overexpression of two pleiotropic regulatory genes, afsS and relA, on moenomycin production. A moenomycin-resistant derivative of S. albus J1074 was found to give the highest titers of moenomycin, and production was improved by overexpressing relA. Part...

  • Therapy for fungal diseases: opportunities and priorities.

    Updated: 2010-03-04 23:00:00
    This article provides a perspective on the current status of drug therapy for invasive fungal diseases, together with priorities for the future development of novel compounds. Key opportunities for new drugs include production of orally bioavailable agents for the treatment of invasive aspergillosis, invasive candidiasis, cryptococcal meningitis and mucosal and urinary Candida infections. Orally bioavailable agents for the treatment of chronic pulmonary and allergic aspergillosis are also required, as well as new potent drugs against a range of medically important moulds. Antifungal resistance is a problem in certain contexts, but is generally less of a problem than bacterial infections. Earlier and more complete mycological diagnosis and improvements in underlying risk estimation will imp...

  • Isolation of Rickettsia parkeri and identification of a novel spotted fever group Rickettsia sp. from Gulf Coast ticks (Amblyomma maculatum) in the United States.

    Updated: 2010-03-04 23:00:00
    In this study, 198 questing adult Gulf Coast ticks were collected from 4 locations in Florida and Mississippi; 28% were infected with R. parkeri and 3% with a novel SFGR. Seventeen isolates of R. parkeri were cultivated in Vero E6 cells from individual specimens of A. maculatum; however, all attempts to isolate the novel SFGR were unsuccessful. Partial genetic characterization of the novel SFGR revealed identity with several recently described, incompletely characterized, and non-cultivated SFGR including Candidatus 'Rickettsia andeanae' and Rickettsia sp. 'Argentina', detected in several species of Neotropical ticks from Argentina and Peru. These findings suggest that each of these 'novel' rickettsiae represent the same species. Our study expands considerably the number of low-passage, A....

  • Single nucleotide polymorphism genotyping showed that mutations leading to a premature stop codon in inlA are common among Listeria monocytogenes isolates from ready-to-eat foods but not human listeriosis cases.

    Updated: 2010-03-04 23:00:00
    Authors: Van Stelten A, Simpson JM, Ward TJ, Nightingale KK Listeria monocytogenes utilizes Internalin A (InlA; encoded by inlA) to cross the intestinal barrier to establish a systemic infection. Multiple naturally-occurring mutations leading to a premature stop codon (PMSC) in inlA have been reported worldwide and these mutations are causally associated with attenuated virulence. Five inlA PMSC mutations recently discovered among isolates from France and the U.S. were included as additional markers in our previously described inlA single nucleotide polymorphism (SNP) genotyping assay. This assay was used to screen >1,000 L. monocytogenes isolates from ready-to-eat (RTE) foods (n=502) and human listeriosis cases (n=507) for 18 inlA PMSC mutations. A significantly (P < 0.0001) gre...

  • Modelling the lag period and exponential growth of Listeria monocytogenes under fluctuating temperature and Aw values.

    Updated: 2010-03-04 23:00:00
    Authors: Muñoz-Cuevas M, Fernández PS, George S, Pin C The dynamic model for the growth of a bacterial population described by Baranyi and Roberts (1994, Int J. Food Microbiol. 23: 277-294) has been applied to model the lag period and exponential growth of L. monocytogenes under fluctuating temperature and Aw values. To model the lag phase duration, the dependence of the parameter, h0, that quantifies the amount of work to be done during the lag period, on the previous and current environmental conditions was determined experimentally. This parameter depended not only on the magnitude of the change between the previous and current environmental factor but also on the current growth conditions. In an exponentially growing population, any change of the environment causing a cer...

  • Glutathione protects Lactobacillus sanfranciscensis against freeze-thawing, freeze-drying, and cold treatment.

    Updated: 2010-03-04 23:00:00
    Authors: Zhang J, Du GC, Zhang Y, Liao XY, Wang M, Li Y, Chen J Lactobacillus sanfranciscensis DSM20451 cells containing glutathione (GSH) displayed a significantly higher resistance against cold stress induced by freeze-drying, freeze-thawing, and 4 degrees C cold treatment. Cells containing GSH were capable of maintaining the membrane structure intact when exposed to freeze-thawing. In addition, cells containing GSH showed a higher proportions of unsaturated fatty acids in cell membranes upon long-term cold treatment. Subsequent study reveals that the protective role of GSH on cell membrane against cryodamage is partly due to preventing peroxidation of membrane fatty acids and protecting Na(+), K(+)-ATPase. The intracellular accumulation of GSH enhanced the survival and the biotechno...

  • Production and characterization of a novel bioflocculant from Bacillus licheniformis.

    Updated: 2010-03-04 23:00:00
    Authors: Xiong Y, Wang Y, Yu Y, Li Q, Wang H, Chen R, He N A bacterium producing an extracellular bioflocculant was isolated from contaminated LB medium and identified as Bacillus licheniformis by 16S rDNA sequence and its biochemical/physiological characteristics. The optimum culture conditions for flocculant production were an initial medium pH of 7.2 and an inoculum size of 4% (vol/vol). The maximum flocculating activity (700 U/ml) was obtained after cultivation at 37 degrees C for 48 hours. Chemical analyses of the purified bioflocculant revealed that it was a proteoglycan composed of 89% carbohydrate and 11% protein (wt/wt). The mass ratio of neutral sugar, amino sugar and uronic acid was measured at 7.9:4:1. Infrared spectrometry further indicated the presence of carboxyl, hydrox...

  • Analysis of Lactobacillus sakei mutants selected after adaptation to the gastrointestinal tract of axenic mice.

    Updated: 2010-03-04 23:00:00
    Authors: Chiaramonte F, Anglade P, Baraige F, Gratadoux JJ, Langella P, Champomier-Vergès MC, Zagorec M We recently showed that Lactobacillus sakei, a natural meat-borne lactic acid bacterium, can colonize the gastrointestinal tract (GIT) of axenic mice but that this colonization in the intestinal environment selects L. sakei mutants showing modified colony morphology (small and rough) and cell shape, most probably resulting from the accumulation of various mutations that confer a selective advantage for persistence in the GIT. In the present study, we analyzed such clones, issued from three different L. sakei strains in order to determine which functions were modified in the mutants. In the elongated filamentous cells of the rough clones, transmission electron microscopy analysis...

  • The influence of refuse tips exploitation in the prevalence of Campylobacter spp. and Salmonella serovars in seagulls.

    Updated: 2010-03-04 23:00:00
    Authors: Ramos R, Cerdà-Cuéllar M, Ramírez F, Jover L, Ruiz X Wild animals are well-known reservoirs of Campylobacter and Salmonella. We investigated the influence of insalubrious diets in the prevalence of both enterobacteria on seagulls. Campylobacter occurrence in gull chicks sampled along the North-Eastern Iberian coast was directly related to the degree of refuse consumption. High Salmonella values along the sampling sites did not reflect any dietary relationship. PMID: 20208027 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)

  • Impact of siderophore production by Pseudomonas syringae pv. syringae 22d/93 on epiphytic fitness and biocontrol activity against Pseudomonas syringae pv. glycinea 1a/96.

    Updated: 2010-03-04 23:00:00
    Authors: Wensing A, Braun SD, Büttner P, Expert D, Völksch B, Ullrich MS, Weingart H The use of naturally occurring microbial antagonists to suppress plant diseases offers a favorable alternative to classical methods of plant protection. The soybean epiphyte, Pseudomonas syringae pv. syringae strain 22d/93 (Pss22d), shows a strong potential to control P. syringae pv. glycinea (Psg), the causal agent of bacterial blight of soybean. Its antagonism against Psg being highly reproducible even in field trials, the involved suppression mechanisms are of special interest. In the current work we demonstrated that Pss22d produced a significant higher amount of siderophores than the pathogen Psg. While both Pss22d and Psg produce the same siderophores, achromobactin and pyoverdin, regul...

  • Raman Spectroscopy Compatible Inactivation Method for Pathogenic Endospores.

    Updated: 2010-03-04 23:00:00
    Authors: Stöckel S, Schumacher W, Meisel S, Elschner M, Rösch P, Popp J Micro-Raman spectroscopy is a fast and sensitive tool for the detection, classification, and identification of biological organisms. The vibrational spectrum inherently serves as a fingerprint of the biochemical composition of each bacterium and thus makes identification at the species, or even subspecies level possible. Therefore, microorganisms in areas susceptible to bacterial contamination, e.g., clinical environments or food-processing technology can be sensed. Within the scope of point-of-care-testing also a detection of intentionally released biosafety level (BSL) 3 agents, like Bacillus anthracis endospores, or their products, is attainable. However, as a matter of fact, no Raman spectroscopic com...

  • Heterologous Expression of the Oxytetracycline Biosynthetic Pathway in Myxococcus xanthus.

    Updated: 2010-03-04 23:00:00
    Authors: Stevens DC, Henry MR, Murphy KA, Boddy CN New natural products for drug discovery may be accessed by heterologous expression of bacterial biosynthetic pathways from metagenomic DNA libraries. However, a "universal" host is needed for this experiment. Herein we show that Myxococcus xanthus is a potential "universal" host for heterologous expression of polyketide biosynthetic gene clusters. PMID: 20208031 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)

  • Proposal of Novosphingobium soli sp. nov., isolated from soil.

    Updated: 2010-03-04 23:00:00
    Authors: Kämpfer P, Young CC, Busse HJ, Lin SY, Rekha PD, Arun AB, Chen WM, Shen FT, Wu YH A yellow pigmented, Gram-negative, rod-shaped, non-spore-forming bacterium (strain CC-TPE-1T), was isolated from oil-contaminated soil near the oil refinery located in Kaohsiung County, Taiwan. The 16S rRNA gene sequence analysis of strain CC-TPE-1T showed highest sequence similarity to Novosphingobium naphthalenivorans DSM 18518T (98.1%), Novosphingobium panipatense SM16T (97.9%), and Novosphingobium mathurense SM117T (97.6%) and lower (< 97%) sequence similarity to all other Novosphingobium species. DNA-DNA hybridizations of strain CC-TPE-1T and N. naphthalenivorans DSM 18518T, N. panipatense SM16T and N. mathurense SM117T showed low similarity values of 30% (reciprocal: 35%), 29.1% (re...

  • Comamonas zonglianii sp. nov., isolated from phenol-contaminated soil.

    Updated: 2010-03-04 23:00:00
    Authors: Yu XY, Li YF, Zheng JW, Li Y, Li L, He J, Li SP A bacterial strain, designated BF-3T, isolated from phenol-contaminated soil, was investigated by polyphasic taxonomic approach. The cells were short rod, Gram-negative, non-sporulating and non-motile. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BF-3T formed a monophyletic branch at the periphery of the evolutionary radiation occupied by the genus Comamonas; it showed highest sequence similarities to Comamonas aquatica LMG 2370T (96.8 %), Comamonas nitrativorans DSM 13191T (96.4 %), Comamonas odontotermitis LMG 23579T (96.4 %), Comamonas kerstersii LMG 3475T (96.3 %), Comamonas koreensis KCTC 12005T (96.1 %) and Comamonas terrigena LMG 1253T (96.0 %). The major cellular fatty acid were 16:0, 18:1/18:...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.

  • Burkholderia oxyphila sp. nov., isolated from acidic forest soil that catabolizes (+)-catechin and its putative aromatic derivatives.

    Updated: 2010-03-04 23:00:00
    Authors: Otsuka Y, Muramatsu Y, Nakagawa Y, Matsuda M, Nakamura M, Murata H The bacterial strain OX-01(T), isolated from acidic soil as an agent that catabolizes (+)-catechin into taxifolin, was taxonomically investigated. The strain OX-01(T) is a Gram-negative, aerobic, non-sporulating, non-motile and rod-shaped bacterium. Phylogenetic position based on the sequence of the 16S rRNA gene assigns this strain as a member of the genus Burkholderia, the position closest to, but clearly distinct from, B. sacchari. The strain OX-01(T) does not have any nif genes required for N(2)-fixation in the genome, a feature that is reminiscent of the luck of nifH in B. sacchari but is distinct from N(2)-fixing features in many other phylogenetically related taxa, such as B. ferrariae, B. heleia, B. mim...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.

  • Searching for monooxygenases and hydrolases in bacteria from an extreme environment.

    Updated: 2010-03-04 23:00:00
    Authors: da Cruz GF, Angolini CF, de Oliveira LG, Lopes PF, de Vasconcellos SP, Crespim E, de Oliveira VM, Dos Santos Neto EV, Marsaioli AJ Microbial oxidation potentials of extremophiles recovered from Pampo Sul oil field, Campos Basin, Brazil, in pure culture or in consortia, were investigated using high-throughput screening (HTS) and multibioreactions. Camphor (1), cis-jasmone (2), 2-methyl-cyclohexanone (3), 1,2-epoxyoctane (4), phenylethyl acetate (5), phenylethyl propionate (6), and phenylethyl octanoate (7) were used to perform multibioreaction assays. Eighty-two bacterial isolates were recovered from oil and formation water samples and those presenting outstanding activities in HTS assays were identified by sequencing their 16S rRNA genes. These results revealed that most micro...

  • Chemoinformatics-assisted development of new anti-biofilm compounds.

    Updated: 2010-03-04 23:00:00
    Authors: Dürig A, Kouskoumvekaki I, Vejborg RM, Klemm P Bacterial biofilms are associated with a large number of infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics, making it hard to eradicate biofilm-associated infections. Here, we use a novel cross-disciplinary approach combining microbiology and chemoinformatics to identify new and efficient anti-biofilm drugs. We found that ellagic acid (present in green tea) significantly inhibited biofilm formation of Streptococcus dysgalactiae. Based on ellagic acid, we performed in silico screening of the Chinese Natural Product Database to predict a 2nd-generation list of compounds with similar characteristics. One of these, esculetin, proved to be more efficient in preventing biofilm formation by Staphylococc...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.

  • Inhibition of neutrophil function following exposure to the Aspergillus fumigatus toxin, fumagillin.

    Updated: 2010-03-03 23:00:00
    Authors: Fallon JP, Reeves EP, Kavanagh KA The filamentous fungus Aspergillus fumigatus produces a variety of enzymes and toxins that may facilitate fungal colonization of tissue and evasion of the host immune response. One such toxin, fumagillin, was investigated for its ability to inhibit the action of neutrophils which are a central component of the innate immune response to microbial infection. Neutrophils exposed to 2 ?g fumagillin ml-1 for 25 minutes showed a significantly reduced ability to kill yeast cells (p < 0.02), to phagocytose conidia of A. fumigatus (p < 0.023) and to consume oxygen (p < 0.032). The ability of neutrophils to generate superoxide is dependent upon the action of a functional NADPH oxidase complex which is composed of cytosolic (p40phox, p47phox, p6...

  • Performance of direct fluorescent antibody staining, point-of-care rapid antigen test and virus isolation for the detection of novel 2009 influenza A (H1N1) virus in comparison to RT-PCR in respiratory specimens.

    Updated: 2010-03-03 23:00:00
    Authors: Ganzenmueller T, Kluba J, Hilfrich B, Puppe W, Verhagen W, Heim A, Schulz T, Henke-Gendo C Although infections with the novel pandemic 2009 influenza A (H1N1) virus (A(H1N1)2009) appeared relatively mild during the first summer of circulation 'off-season'), there has been significant morbidity, hospitalization, and several fatal cases. Thus, rapid detection of A(H1N1)2009 is crucial for efficient treatment and infection control measures. In contrast to seasonal influenza, where point-of-care (POC) rapid antigen tests and direct fluorescent antibody (DFA) staining ensure rapid detection, diagnosis of A(H1N1)2009 is hitherto based on RT-PCR. We retrospectively analyzed the performance of the Quidel QuickVue POC test, DFA staining and virus isolation for A(H1N1)2009 detection in ...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.

  • Fatal congenital tuberculosis due to Beijing strain in a premature neonate.

    Updated: 2010-03-03 23:00:00
    This report summarizes a congenital tuberculosis case in a very premature infant, born at twenty-five weeks gestation. Miliary tuberculosis was diagnosed in mother when the neonate was twenty days old. An antituberculous therapy allowed a rapid improvement in mother. The infant died at twenty-seven days old. A Beijing genotype strain of Mycobacterium tuberculosis was isolated both in mother from pulmonary and urine specimens and in infant from peritoneal fluid. PMID: 20203217 [PubMed - as supplied by publisher] (Source: Journal of Medical Microbiology)

  • Tuning the flagellar motor.

    Updated: 2010-03-03 23:00:00
    Authors: Thormann KM, Paulick A Many bacteria are motile by means of flagella, semi-rigid helical filaments rotated at the filament's base and energized by proton or sodium-ion gradients. Torque is created between the two major components of the flagellar motor: the rotating switch complex and the cell wall-associated stators which are arranged in a dynamic ring-like structure. Being motile provides a survival advantage to many bacteria, thus, the flagellar motor should work optimally under a wide range of environmental conditions. Recent studies have demonstrated that numerous species possess a single flagellar system but two or more individual stator systems that contribute differentially to flagellar rotation. This review describes recent findings on rotor-stator interactions, on th...

  • A sulphite-inducible form of the sulphite efflux gene SSU1 in a Saccharomyces cerevisiae wine yeast.

    Updated: 2010-03-03 23:00:00
    In this study, we characterised the unusual expression pattern of SSU1 in the wine strain 71B. We provide, for the first time, evidence of SSU1 induction by sulphite. The study of SSU1 expression during fermentation and in different growth conditions showed that sulphite is the main regulator of SSU1 expression, explaining its specific pattern. Combining analyses of gene expression and growth behaviour in response to sulphite, we found that 71B displayed unique behavioural patterns in response to sulphite pre-adaptation that may be explained by changes in SSU1 expression. Examination of the genomic organisation of the SSU1 locus and sequencing of the region revealed three different alleles in 71B, two of which corresponded to translocated VIII-XVI forms. The lack of differences between pro...

  • Stereospecific recognition of pyochelin and enantio-pyochelin by the PchR proteins in fluorescent pseudomonads.

    Updated: 2010-03-03 23:00:00
    Authors: Youard ZA, Reimmann CE The siderophore pyochelin of Pseudomonas aeruginosa promotes growth under iron limitation and induces the expression of its biosynthesis genes via the transcriptional AraC/XylS-type regulator PchR. Pseudomonas fluorescens strain CHA0 makes the optical antipode of pyochelin termed enantio-pyochelin, which also promotes growth and induces the expression of its biosynthesis genes when iron is scarce. Growth promotion and signalling by pyochelin and enantio-pyochelin are highly stereospecific and are known to involve the pyochelin and enantio-pyochelin outer membrane receptors FptA and FetA, respectively. Here we show that stereospecificity in signalling is also based on the stereospecificity of the homologous PchR proteins of P. aeruginosa and P. fluorescen...

  • Regulation of flagellar, motility and chemotaxis genes in Rhizobium leguminosarum by the VisNR/Rem cascade.

    Updated: 2010-03-03 23:00:00
    Authors: Tambalo DD, Del Bel KL, Bustard DE, Greenwood PR, Steedman AE, Hynes MF In this paper, we describe the regulatory roles of VisN, VisR, and Rem in the expression of flagellar, motility and chemotaxis genes in Rhizobium leguminosarum biovar viciae strains VF39SM and 3841. Individual mutations in the genes coding for these proteins resulted in a loss of motility and an absence of flagella, indicating that these regulatory genes are essential for flagellar synthesis and function. Transcriptional experiments involving gusA-gene fusions in wildtype and mutant backgrounds were performed to identify the genes under VisN/R and Rem regulation. Results showed that the chemotaxis and motility genes of R. leguminosarum could be separated into two groups; one group under VisN/R-Rem regulati...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.

  • Morphology and General Characteristics of Bacteriophages Infectious to Robinia pseudoacacia Mesorhizobia.

    Updated: 2010-03-03 23:00:00
    Authors: Turska-Szewczuk A, Pietras H, Pawelec J, Mazur A, Russa R Four phages infectious to Mesorhizobium strains were identified in soil samples taken from local Robinia pseudoacacia stands. Based on their polyhedral heads and short noncontractile tails, three of the phages, Mlo30, Mam12, and Mam20, were assigned to group C of Bradley's classification, the Podoviridae family, while phage Mlo1, with its elongated hexagonal head and a long flexible tail represented subgroup B2 bacteriophages, the Siphoviridae family. The phages were homogeneous in respect of their virulence, as they only lysed Mesorhizobium strains, but did not affect strains of Rhizobium or Bradyrhizobium. On the basis of one-step growth experiments, the average virus yield was calculated as approximately 10-25 phage ...

  • Lipid production from Jerusalem artichoke by Rhodosporidium toruloides Y4.

    Updated: 2010-03-03 23:00:00
    Authors: Zhao X, Wu S, Hu C, Wang Q, Hua Y, Zhao ZK Jerusalem artichoke (JA) is a perennial herbaceous plant widely available as non-grain raw material. Microbial lipid has been suggested as a potential feedstock for large scale biodiesel production. This paper describes lipid production using JA tuber processed by oleaginous yeast Rhodosporidium toruloides Y4. Batch and fed-batch modes were tested with feeding of concentrated JA extracts or JA hydrolysates. Cultivation of R. toruloides Y4 with JA extracts gave a moderate cellular lipid content of 40% (w/w), whereas lipid titer and cellular lipid content reached 39.6 g l(-1) and 56.5% (w/w), respectively, when JA hydrolysates were fed. Our results suggested that JA tubers may be further explored as raw material for large scale microbia...

  • Purification and characterization of the exopolygalacturonase produced by Aspergillus giganteus in submerged cultures.

    Updated: 2010-03-03 23:00:00
    We present here an efficient, simple, and inexpensive method for purifying the A. giganteus PG and describe the characteristics of the purified enzyme. Purified PG was obtained after two simple steps: (1) protein precipitation with 70% ammonium sulfate saturation and (2) anion-exchange chromatography on a DEAE-Sephadex A-50 column. The final enzyme solution retained 86.4% of its initial PG activity. The purified PG had a molecular weight of 69.7 kDa, exhibited maximal activity at pH 6.0 and 55-60 degrees C, and was stable in neutral and alkaline media. It had a half-life of 115, 18, and 6 min at 40, 50 and 55 degrees C, respectively. Purified PG showed its highest hydrolytic activity with low-esterified and nonesterified substrates, releasing monogalacturonic acid from substrate, indicatin...

  • Production of a novel extracellular acidic lipase from Pseudomonas gessardii using slaughterhouse waste as a substrate.

    Updated: 2010-03-03 23:00:00
    Authors: Ramani K, Chockalingam E, Sekaran G An isolate exhibiting high extracellular lipolytic activity was identified as Pseudomonas gessardii by 16S rDNA gene sequence analysis. The slaughterhouse waste, goat tallow, was used as a lipid substrate for the production of acidic lipase by P. gessardii. The maximum lipase activity of 156 U/ml was observed at an acidic pH of 3.5 and at 0.31 g substrate concentration. The purification steps resulted in the isolation of acidic lipase with a specific activity of 1,473 U/mg and a molecular weight of 94 kDa. One interesting feature of this purified lipase is its stability at highly acidic pH ranging from 2.0 to 5.5 with a high molecular weight. The amino acid composition was determined using HPLC. This acidic lipase has potential applications ...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.

  • The influence of nitrogen limitation on mcl-PHA synthesis by two newly isolated strains of Pseudomonas sp.

    Updated: 2010-03-03 23:00:00
    Authors: Ciesielski S, Możejko J, Przybyłek G The nucleotide composition of key enzymes involved in medium-chain-length polyhydroxyalkanoates (mcl-PHA) synthesis was analyzed in two newly isolated strains of Pseudomonas. The isolated strains were tested for their abilities to synthesize polyhydroxyalkanoates using three different substrates as a carbon source: sodium octanoate, oleic acid, and sodium gluconate. Both analyzed strains were able to accumulate mcl-PHA in a range from 2.07 to 21.40%, which depended on the substrate used. Potential nitrogen-dependent regulation of mcl-PHA synthesis was analyzed by cell cultivation in nitrogen-limiting and non-limiting conditions. The analyzed strains demonstrated an incremental increase of mcl-PHAs in response to nitrogen starvat...

  • Electricity-mediated biological hydrogen production.

    Updated: 2010-03-02 23:00:00
    Authors: Geelhoed JS, Hamelers HV, Stams AJ Anaerobic bacteria have the ability to produce electricity from the oxidation of organic substrates. They also may use electricity to support chemical reactions that are energetically unfavorable. In the fermentation of sugars, hydrogen can be formed as one of the main products. However, a yield of only four hydrogen per molecule of glucose can be achieved. Potentially, eight additional hydrogen molecules could be produced when the other main fermentation product acetate is converted further, which however is energetically not possible. By the input of electricity, acetate can be oxidized further to form hydrogen. This paper reviews the scarce knowledge of how electricity can be used to produce hydrogen in the microbial oxidation of acetate o...

  • Comparison of 16S rRNA gene phylogeny and functional tfdA gene distribution in thirty-one different 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid degraders.

    Updated: 2010-03-02 23:00:00
    Authors: Bælum J, Jacobsen CS, Holben WE 31 different bacterial strains isolated using the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole source of carbon, were investigated for their ability to mineralize 2,4-D and the related herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Most of the strains mineralize 2,4-D considerably faster than MCPA. Three novel primer sets were developed enabling amplification of full-length coding sequences (CDS) of the three known tfdA gene classes, known to be involved in phenoxy acid degradation. 16S rRNA genes were also sequenced and in order to investigate possible linkage between tfdA gene classes and bacterial species, tfdA and 16S rRNA gene phylogeny was compared. Three distinctly different classes of tfdA genes were observed,...

  • Changes in Pelagic Bacteria Communities Due to Leaf Litter Addition.

    Updated: 2010-03-02 23:00:00
    Authors: Hutalle-Schmelzer KM, Zwirnmann E, Krüger A, Grossart HP In many limnetic systems, the input of allochthonous organic matter, e.g., leaf litter, is a substantial source of dissolved organic carbon (DOC) for pelagic bacteria, especially in fall and winter when autochthonous DOC production is low. However, relatively little is known about community changes of pelagic lake bacteria due to leaf litter input which includes both the release of leaf leachates and microorganisms from the leaf litter into the surrounding water. Therefore, we have experimentally studied the effects of different types of leaf litter (Betula pendula, Fagus silvatica, and Pinus silvestris) on the pelagic bacterial community composition by adding leaves to different treatments of epilimnic water sample...

  • The rag locus of Porphyromonas gingivalis might arise from Bacteroides via horizontal gene transfer

    Updated: 2010-03-02 09:03:24
    Abstract nbsp; Porphyromonas gingivalis is regarded as one of the risk factors of periodontitis. P. gingivalis exhibits a wide variety of genotypes. Many insertion sequences (ISs), located in their chromosomes, made P. gingivalis differentiate into virulent and avirulent strains. In this research, we investigated the prevalence of P. gingivalis in the gingival crevicular fluid (GCF) among periodontitis patients from Zhenjiang, China, detected the P. gingivalis rag locus distributions by multiplex polymerase chain reaction (PCR), and analyzed the origin of the P. gingivalis rag locus based on evolution. There were three rag locus variants co-existing in Zhenjiang. The results showed that the rag locus may be associated with severe periodontitis. This work also firstly ascertained tha...

  • Gaining ground: assays for therapeutics against botulinum neurotoxin.

    Updated: 2010-03-01 23:00:00
    Authors: Hakami RM, Ruthel G, Stahl AM, Bavari S Owing in part to recently heightened concern over bioterrorism, interest in the mechanism of action of botulinum neurotoxin (BoNT) and development of effective therapeutic strategies has dramatically increased. The emergence of BoNT as an effective treatment for a variety of neurological disorders and its growing use in the cosmetic industry have also increased interest in developing effective countermeasures. Although recent attempts to create effective vaccines appear promising, the multitude of clinical and cosmetic uses of BoNT make mass vaccination against the toxin undesirable and impractical, leading to intensified efforts to develop effective therapeutics to combat large-scale intoxications. In this review, we examine the relevan...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.

  • When metagenomics meets stable-isotope probing: progress and perspectives.

    Updated: 2010-03-01 23:00:00
    Authors: Chen Y, Murrell JC The application of metagenomics, the culture-independent capture and subsequent analysis of genomic DNA from the environment, has greatly expanded our knowledge of the diversity of microbes and microbial protein families; however, the metabolic functions of many microorganisms remain largely unknown. DNA stable-isotope probing (DNA-SIP) is a recently developed method in which the incorporation of stable isotope from a labelled substrate is used to identify the function of microorganisms in the environment. The technique has now been used in conjunction with metagenomics to establish links between microbial identity and particular metabolic functions. The combination of DNA-SIP and metagenomics not only permits the detection of rare low-abundance species from...

  • Regulatory roles of the bacterial nitrogen-related phosphotransferase system.

    Updated: 2010-03-01 23:00:00
    Authors: Pflüger-Grau K, Görke B In addition to the sugar phosphotransferase system (sugar PTS) dedicated to carbohydrate uptake, many Gram-negative bacteria possess a so-called nitrogen PTS (PTS(Ntr)). Although fulfilling very different functions, both systems can communicate with each other by phosphate exchange. PTS(Ntr) regulates diverse processes implicated in metabolism of nitrogen and carbon, and is essential for virulence in some bacteria. Additionally, it plays a role in potassium homeostasis by regulating the expression and activity of a high- and a low-affinity K(+) transporter, respectively. In this article, we review recent advances in the understanding of the regulatory roles of PTS(Ntr) in various organisms. PMID: 20202847 [PubMed - as supplied by publisher...

  • Seasonal and regional diversity of maple sap microbiota revealed using community PCR fingerprinting and 16S rRNA gene clone libraries.

    Updated: 2010-03-01 23:00:00
    Authors: Filteau M, Lagacé L, Lapointe G, Roy D An arbitrary primed community PCR fingerprinting technique based on capillary electrophoresis was developed to study maple sap microbial community characteristics among 19 production sites in Québec over the tapping season. Presumptive fragment identification was made with corresponding fingerprint profiles of bacterial isolate cultures. Maple sap microbial communities were subsequently compared using a representative subset of 13 16S rRNA gene clone libraries followed by gene sequence analysis. Results from both methods indicated that all maple sap production sites and flow periods shared common microbiota members, but distinctive features also existed. Changes over the season in relative abundance of predominant populations sh...

  • Asexual Endophytes in a Native Grass: Tradeoffs in Mortality, Growth, Reproduction, and Alkaloid Production.

    Updated: 2010-03-01 23:00:00
    Authors: Faeth SH, Hayes CJ, Gardner DR Neotyphodium endophytes are asexual, seed-borne fungal symbionts that are thought to interact mutualistically with their grass hosts. Benefits include increased growth, reproduction, and resistance to herbivores via endophytic alkaloids. Although these benefits are well established in infected introduced, agronomic grasses, little is known about the cost and benefits of endophyte infection in native grass populations. These populations exist as mosaics of uninfected and infected plants, with the latter often comprised of plants that vary widely in alkaloid content. We tested the costs and benefits of endophyte infections with varying alkaloids in the native grass Achnatherum robustum (sleepygrass). We conducted a 4-year field experiment, where he...

  • Identification and characterization of genes involved in naphthalene degradation in Rhodococcus opacus R7.

    Updated: 2010-03-01 23:00:00
    Authors: Di Gennaro P, Terreni P, Masi G, Botti S, De Ferra F, Bestetti G Rhodococcus opacus R7 is a naphthalene-degrading microorganism which is also able to grow on o-xylene. This work describes the isolation and analysis of two new genomic regions in which genes involved in naphthalene (nar gene cluster) and salicylate (gen gene cluster) degradation are located. In the nar gene cluster we found: two genes encoding the large (narAa) and the small (narAb) components of the naphthalene dioxygenase, three genes (rub1, rub2, rub1bis) encoding three rubredoxins, an orf (orf7) associated to the complex encoding a protein of unknown function, two regulatory genes (narR1, narR2), a gene (narB) encoding the naphthalene dihydrodiol dehydrogenase and six orfs (orf1, orf2, orf3, orf4, orf5, orf6...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.

  • Genetic improvement of brewer's yeast: current state, perspectives and limits.

    Updated: 2010-03-01 23:00:00
    Authors: Saerens SM, Duong CT, Nevoigt E Brewer's yeast strain optimisation may lead to a more efficient beer production process, better final quality or healthier beer. However, brewer's yeast genetic improvement is very challenging, especially true when it comes to lager brewer's yeast (Saccharomyces pastorianus) which contributes to 90% of the total beer market. This yeast is a genetic hybrid and allopolyploid. While early studies applying traditional genetic approaches encountered many problems, the development of rational metabolic engineering strategies successfully introduced many desired properties into brewer's yeast. Recently, the first genome sequence of a lager brewer's strain became available. This has opened the door for applying advanced omics technologies and facilitati...

  • Reconstructing the clostridial n-butanol metabolic pathway in Lactobacillus brevis.

    Updated: 2010-03-01 23:00:00
    Authors: Berezina OV, Zakharova NV, Brandt A, Yarotsky SV, Schwarz WH, Zverlov VV A Lactobacillus brevis strain with the ability to synthesize butanol from glucose was constructed by metabolic engineering. The genes crt, bcd, etfB, etfA, and hbd, composing the bcs-operon, and the thl gene encode the enzymes of the lower part of the clostridial butanol pathway (crotonase, butyryl-CoA-dehydrogenase, two subunits of the electron transfer flavoprotein, 3-hydroxybutyryl-CoA dehydrogenase, and thiolase) of Clostridium acetobutylicum. They were cloned into the Gram-positive/Gram-negative shuttle plasmid vector pHYc. The two resulting plasmids pHYc-thl-bcs and pHYc-bcs (respectively, with and without the clostridial thl gene) were transferred to Escherichia coli and L. brevis. The recombinant ...

  • Characterization of a Novel Trimethoprim Resistance Gene, dfrA28, in Class 1 Integron of an Oligotrophic Acinetobacter johnsonii Strain, MB52, Isolated from River Mahananda, India

    Updated: 2010-03-01 19:40:01
    Microbial Drug Resistance , Vol. 0, No. 0. (Source: Microbial Drug Resistance)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.

  • Low-dose β-lactam plus amikacin in febrile neutropenia: cefepime vs. piperacillin/tazobactam, a randomized trial

    Updated: 2010-03-01 17:08:40
    Abstract nbsp;Patients with fever and granulocytopenia are at risk of developing severe infection. We performed a prospective, randomized trial to evaluate the efficacy of low-dose cefepime plus amikacin (C-A) compared to low-dose piperacillin/tazobactam plus amikacin (PT-A). Patients received cefepime (2 /12 ) plus amikacin (15 g/kg/day) or piperacillin/tazobactam (4 /500 g/8 ) plus amikacin. A total of 317 episodes of febrile granulocytopenia in 190 patients were studied (152 in the C-A group, 165 in the PT-A group). A microbiologically documented infection was present in 53 (35%) episodes in the C-A group and 41 (25%) episodes in the PT-A group (p = ns); a clinically documented infection was observed in 39 (26%) and 47 (28%) episodes, r...

  • Distribution of Chlamydia trachomatis ompA genovars and the new variant of C. trachomatis in the Göteborg area, Sweden

    Updated: 2010-03-01 17:08:38
    Abstract nbsp;The aims of this study were to assess the proportion of the new variant of Chlamydia trachomatis (nvCT) and the distribution of ompA genovars among C. trachomatis-positive patients in the Göteborg area, Sweden. Consecutive urine samples positive for C. trachomatis using BD ProbeTec ET (177 patients, 88 men and 89 women) were collected. An nvCT-specific real-time polymerase chain reaction (PCR) assay was used to investigate the nvCT prevalence. To identify the genovars, a 990-bp ompA DNA segment from 105 specimens was sequenced. Seventeen percent (30/177) of all specimens contained nvCT. Nine different genovars were identified. About 50% were of genovar E, followed by F 16%, G 11%, K 8%, and D 5%, representing about 90% of the specimens in Göteborg. The occurrence o...

  • Efflux Pumps, OprD Porin, AmpC {beta}-Lactamase and Multiresistance in Pseudomonas aeruginosa Isolates from Cystic Fibrosis.

    Updated: 2010-02-28 23:00:00
    Authors: Tomas M, Doumith M, Warner M, Turton JF, Beceiro A, Bou G, Livermore DM, Woodford N Expression of ampC, oprD, mexA, mexC, mexE, and mexX was studied in 25 Pseudomonas aeruginosa from cystic fibrosis patients, including 14 isolates of the 'Liverpool' epidemic strain. Overexpressed mexA or ampC and reduced oprD were associated with beta-lactam resistance. A specific combination of mexR, nalC and nalD mutations occurred in 11 'Liverpool' strain isolates, including 7 with up-regulated mexA. PMID: 20194693 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

  • A novel azolo-1,2,4-triazine-derived inhibitor of influenza a and b virus replication: antiviral properties, metabolism, and pharmacokinetics.

    Updated: 2010-02-28 23:00:00
    A NOVEL AZOLO-1,2,4-TRIAZINE-DERIVED INHIBITOR OF INFLUENZA A AND B VIRUS REPLICATION: ANTIVIRAL PROPERTIES, METABOLISM, AND PHARMACOKINETICS. Antimicrob Agents Chemother. 2010 Mar 1; Authors: Karpenko I, Deev S, Kiselev O, Charushin V, Rusinov V, Ulomsky E, Deeva E, Yanvarev D, Ivanov A, Smirnova O, Kochetkov S, Chupakhin O, Kukhanova M Influenza viruses of types A and B cause periodic pandemics in the human population. The antiviral drugs approved to combat influenza virus infections are currently limited. We have investigated a novel effective inhibitor of human influenza A and B virus triazavirine (2-methylthio-6-nitro-1,2,4-triazolo[5,1-C]-1,2,4-triazine-7(4H)-one, TZV). TZV suppressed replication of influenza virus in cell culture, chicken chorioallantoic membranes, prote...

  • Affinity of Ceftaroline and Other {beta}-Lactams for Penicillin-Binding Proteins from Staphylococcus aureus and Streptococcus pneumoniae.

    Updated: 2010-02-28 23:00:00
    Authors: Kosowska-Shick K, McGhee PL, Appelbaum PC We compared the affinity to all penicillin-binding proteins (PBPs) of ceftaroline with those of ceftriaxone and cefotaxime in 6 Staphylococcus aureus and 7 Streptococcus pneumoniae isolates of varying resistance phenotypes. Ceftaroline MICs were </=1 mug/ml against all S. aureus isolates, and were </=0.25 mug/ml for 4 of 7 isolates of S. pneumoniae. Ceftaroline affinities for penicillin-susceptible S. pneumoniae strain were PBP2X, 3 > 1A, 1B, 2A > 2B and ceftaroline had >/=4-fold higher IC50 (0.1-4 mug/ml) for PBP2X, 2A, 2B, and 3 compared to other cephalosporins tested. Among 3 penicillin-resistant S. pneumoniae strains, ceftaroline had high affinity to PBP2X (IC50 0.1-1 mug/ml), a primary target for cephalosporin PBP b...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.

  • New Book on Lentiviruses published today

    Updated: 2010-02-28 23:00:00
    A new book on Lentiviruses edited by Moira Desport has been has been published today read more ...Lentiviruses and Macrophages: Molecular and Cellular Interactions Edited by: Moira DesportISBN: 978-1-904455-60-8Publisher: Caister Academic PressPublication Date: March 2010Cover: Hardback (Source: Microbiology Blog: The weblog for microbiologists.)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.

  • Book Review: RNA Interference and Viruses

    Updated: 2010-02-28 23:00:00
    RNA Interference and Viruses"a timely and well-compiled book, authored by several distinguished scientists who have made significant contributions to this important area of emerging research. The book consists of 11 chapters dealing with various aspects of the relevance of RNAi to viral infections in plant, insect and mammalian cells ... the book addresses a range of important fundamental issues that may impact on the development of RNAi-based therapies against several human diseases. It provides a solid introduction to the general concepts in the field of RNAi, how viruses modulate RNAi responses as well as issues involved in using RNAi as antiviral therapy. Thus, this book will be useful to a wide range of readership- from basic science students, to RNAi researchers, to virologists, to i...

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