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Microbiology Medical and Health News Headlines
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All Recent Microbiology Medical News Headlines |
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The Plasmodium falciparum protein Pfg27 is dispensable for gametocyte and gamete production, but contributes to cell integrity during gametocytogenesis
In the human malaria parasite Plasmodium falciparum, gametocyte maturation is a process remarkably longer than in other malaria species, accompanied by expression of 2[ndash]300 sexual stage-specific proteins. Disruption of several of their encoding genes so far showed that only the abundant protein Pfg27, produced at the onset of sexual differentiation, is essential for gametocyte production. In contrast with what has been previously described, here we show that P. falciparum pfg27 disruptant lines are able to undergo all stages of gametocyte maturation, and are able to mature into gametes. A fraction of Pfg27-defective gametocytes show, however, distinct abnormalities in intra- and extra-cellular membranous compartments, such as accumulation of parasitophorous vacuole-derived vesicles in......
POSTED 06/30/2009 at 06:00 PM --
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Simultaneous differential detection of Chlamydophila abortus, Chlamydophila pecorum and Coxiella burnetii from aborted ruminant's clinical samples using multiplex PCR
Conclusions:
We have successfully developed a rapid multiplex PCR that can detect and differentiate Cp. abortus, Cp. pecorum and C. burnetii; with a good sensitivity and specificity. The diagnosis of chlamydiosis and Q fever may be greatly simplified and performed at low cost. In addition, the improvement in diagnostic techniques will enhance our knowledge regarding the prevalence and the pathogenetic significance of Q fever and chlamydiosis (Source: BMC Microbiology - Latest articles)...
POSTED 06/30/2009 at 06:00 PM --
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Developing a scalable model of recombinant protein yield from Pichia pastoris: the influence of culture conditions, biomass and induction regime
Conclusions:
We demonstrate how a rational, stepwise approach to recombinant protein production screens can reduce process development time. (Source: Microbial Cell Factories)...
POSTED 06/30/2009 at 06:00 PM --
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Review of "Insect Pathogens: Molecular Approaches and Techniques" by S. P. Stock, J. Vandenberg, I. Glazer and N. Boemare
Review of "Insect Pathogens: Molecular Approaches and Techniques" by S. P. Stock, J. Vandenberg, I. Glazer and N. Boemare (Source: Parasites and Vectors)...
POSTED 06/30/2009 at 06:00 PM --
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Retrospective analysis of the genetic diversity of Klebsiella oxytoca isolated in Poland over a 50-year period
In conclusion, we found that the ITS-PCR
and PCR MP methods are useful for the phylogenetic delineation of genetic groups in K. oxytoca.
Content Type Journal ArticleCategory Brief ReportDOI 10.1007/s10096-009-0768-7Authors
K. Stojowska, Gdańsk University of Technology Department of Microbiology ul. G. Narutowicza 11/12 80-233 Gdańsk PolandB. Krawczyk, Gdańsk University of Technology Department of Microbiology ul. G. Narutowicza 11/12 80-233 Gdańsk PolandS. Kałużewski, National Institute of Public Health, National Institute of Hygiene Department of Bacteriology ul. Chocimska 24 00-791 Warszawa PolandJ. Kur, Gdańsk University of Technology Department of Microbiology ul. G. Narutowicza 11/12 80-233 Gdańsk Poland
Journal European Journal of Clinical Microbiology & Infectio......
POSTED 06/29/2009 at 05:22 AM --
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Comparison of two PCR-based methods and conventional culture for the detection of nasal carriage of Staphylococcus aureus in pre-operative patients
Abstract Nasal carriage is an important risk factor for the development of post-operative infections with Staphylococcus aureus and pre-operative treatment with mupirocin in carriers reduces the post-operative infection rate. Therefore, it is important
to identify nasal carriage rapidly. Two polymerase chain reaction (PCR) techniques were compared to conventional culture in
surgical patients. In 404 consecutive patients, nasal swabs were taken for pre-operative screening for the nasal carriage
of S. aureus. The performance of the Roche Staphylococcus Kit on Lightcycler (Roche; RSA) and the Becton Dickinson (San Diego, CA) GeneOhm
StaphSR assay on Smartcycler (Cepheid; BDSA) were compared with semi-quantitative culture. The sensitivity for culture, RSA
and BDSA compared to t......
POSTED 06/29/2009 at 05:22 AM --
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Interaction of dietary resveratrol with animal-associated bacteria
Resveratrol (3,5,4'-trihydroxy-trans-stilbene), an antifungal phytoalexin produced by grapes, peanuts, and Japanese knotweeds, is thought to be a beneficial dietary phytochemical in red wine and grape juice. Information on its antibacterial properties and biotransformation, however, is limited. We surveyed the interactions of resveratrol with 43 strains of bacterial species that are often animal- or human-associated. Resveratrol at 50 mg L[minus]1 reduced the growth rates of most of the bacteria tested, but did not totally prevent growth even at much higher levels. Eleven of the 43 bacteria were capable of transforming at least 20% of the resveratrol. Three major metabolites were identified as resveratroloside, piceid, and dihydroresveratrol, and three other metabolites were partially char......
POSTED 06/28/2009 at 06:00 PM --
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The PhyR-σEcfG signalling cascade is involved in stress response and symbiotic efficiency in Bradyrhizobium japonicum
PhyR is an unusual type of response regulator consisting of a receiver domain and an extracytoplasmic function (ECF) sigma factor-like domain. It was recently described as a master regulator of general stress response in Methylobacterium extorquens. Orthologues of this regulator are present in essentially all free-living Alphaproteobacteria. In most of them, phyR is genetically closely linked to a gene encoding an ECF [sigma] factor. Here, we investigate the role of these two regulators in the soybean symbiont Bradyrhizobium japonicum USDA110. Using deletion mutants and phenotypic assays, we showed that PhyR and the ECF [sigma] factor [sigma]EcfG are involved in heat shock and desiccation resistance upon carbon starvation. Both mutants had symbiotic defects on the plant hosts Glycine max (......
POSTED 06/28/2009 at 06:00 PM --
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Polyphasic taxonomy of novel actinobacteria showing macromolecule degradation potentials in Bigeum Island, Korea.
Authors: Dastager SG, Pandey A, Lee JC, Li WJ, Kim CJ
Aerobic, alkaliphilic to alkalitolerant and mesophilic bacteria were isolated and characterized from soil and sediment samples collected from Bigeum Island, South Korea. The total numbers of microorganisms in the soil and sediment samples were found to be 10(3)-10(5) cfu/g and 10(2)-10(7) cfu/g, respectively. A total of 163 isolates were isolated and subjected to further characterization on the basis of pH, temperature and salt tolerance. Among the 163 isolates, 54 were selected based on their tolerance attributes to temperature, pH and NaCl. Out of the 54 isolates, 27 were further selected based on their multiple tolerance ability and enzyme profile and were subjected to 16S rRNA gene sequencing and phylogenetic analysis. The latte......
POSTED 06/28/2009 at 12:54 AM --
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The essential histone-like protein HU plays a major role in Deinococcus radiodurans nucleoid compaction
In this report, we focused our study on the role of HU protein, a nucleoid-associated protein referred to as a histone-like protein, in the nucleoid compaction of D. radiodurans. We demonstrate, using a new system allowing conditional gene expression, that HU is essential for viability in D. radiodurans. Using a tagged HU protein and immunofluorescence microscopy, we show that HU protein localizes all over the nucleoid and that when HU is expressed from a thermosensitive plasmid, its progressive depletion at the non-permissive temperature generates decondensation of DNA before fractionation of the nucleoid into several entities and subsequent cell lysis. We also tested the effect of the absence of Dps, a protein also involved in nucleoid structure. In contrast to the drastic effect of HU d......
POSTED 06/27/2009 at 06:00 PM --
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Development of an enzyme activity screening system for beta-glucosidase-displaying yeasts using calcium alginate micro-beads and flow sorting.
Authors: Zhou Y, Kajiyama S, Itoh K, Tanino T, Fukuda N, Tanaka T, Kondo A, Fukui K
Recent reports on high-speed affinity screening systems for yeast cells using flow cytometry have not been adapted to screening yeast cells that display hydrolyzing enzymes, since the fluorescent molecules which are released from fluoresceinated substrate diffuse into solution after enzymatic reaction. In this research, yeast cells displaying beta-glycosidase were individually captured in micro-sized calcium alginate beads by using the newly developed reverse micelle method to prevent diffusion of hydrolyzed fluorescent substrates. By adopting flow sorting to these captured cells, active cells were successfully enriched about 82-fold from a mixed suspension with negative controls. This system should be ......
POSTED 06/26/2009 at 06:00 PM --
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Stimulation of artemisinin synthesis by combined cerebroside and nitric oxide elicitation in Artemisia annua hairy roots.
Authors: Wang JW, Zheng LP, Zhang B, Zou T
This work examined the accumulation of artemisinin and related secondary metabolism pathways in hairy root cultures of Artemisia annua L. induced by a fungal-derived cerebroside (2S,2'R,3R,3'E,4E,8E)-1-O-beta-D: -glucopyranosyl-2-N-(2'-hydroxy-3'-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine. The presence of the cerebroside induced nitric oxide (NO) burst and artemisinin biosynthesis in the hairy roots. The endogenous NO generation was examined to be involved in the cerebroside-induced biosynthesis of artemisinin by using NO inhibitors, N (omega)-nitro-L: -arginine methyl ester and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. The gene expression and activity of 3-hydroxy-3-methylglutaryl CoA reductase and 1-deoxy-D:......
POSTED 06/26/2009 at 06:00 PM --
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Development of a PCR assay for typing and subtyping of Brucella species.
Authors: Huber B, Scholz HC, Lucero N, Busse HJ
In the course of this study, examinations were carried out to develop a PCR-based test which allows discrimination of Brucella species and biovars not targeted by the currently established gel-based PCR assays. Appropriate primers were designed based on specific deletions and insertions in the different Brucella genomes as determined by RAPD-PCR and whole-genome comparisons. After testing the specificity of the primers with a set of 22 Brucella reference strains of all species and biovars, they were used to supplement the existing PCR assays resulting in a 19-primer multiplex PCR. In addition to the commonly used PCR assays, the developed assay specifically identified B. neotomae, B. pinnipedialis, B. ceti, and B. microti. Furthermore, it......
POSTED 06/25/2009 at 06:00 PM --
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Modelling the black death. A historical case study and implications for the epidemiology of bubonic plague.
Authors: Monecke S, Monecke H, Monecke J
We analysed a plague outbreak in the mining town of Freiberg in Saxony which started in May 1613 and ended in February 1614. This epidemic was selected for study because of the high quality of contemporary sources. It was possible to identify 1400 individual victims meaning that more than 10% of the population of the city perished. The outbreak was modelled by 9 differential equations describing flea, rat, and human populations. This resulted in a close fit to the historical records of this outbreak. An interesting implication of the model is that the introduction of even a small number of immune rats into an otherwise unchanged setting results in an abortive outbreak with very few human victims. Hence, the percentage of immune rats directly inf......
POSTED 06/25/2009 at 06:00 PM --
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Metabolic capacity of Sinorhizobium (Ensifer) meliloti strains detected by phenotype microarray.
Authors: Biondi EG, Tatti E, Comparini D, Giuntini E, Mocali S, Giovannetti L, Bazzicalupo M, Mengoni A, Viti C
Sinorhizobium meliloti is a soil bacterium that fixes atmospheric nitrogen in plant roots. The high genetic diversity of its natural populations has been the subject of extensive analysis. Recent genomic studies on several isolates revealed a high content of variable genes suggesting a corresponding large phenotypic differentiation among strains of S. meliloti species. Here, using the Phenotype Microarray (PM) technique, hundreds of different growth conditions were tested in order to compare the metabolic capabilities of the laboratory reference strain Rm1021 with four natural S. meliloti isolates, previously analyzed by comparative genomic hybridization (CHG). Results of PM ......
POSTED 06/25/2009 at 06:00 PM --
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A Comparative study of species richness estimates obtained using nearly complete fragments and simulated pyrosequencing-generated fragments in 16S rRNA gene-based environmental surveys.
Authors: Youssef N, Sheik CS, Krumholz LR, Najar FZ, Roe BA, Elshahed MS
Pyrosequencing-based 16S rRNA gene surveys are increasingly utilized to study highly diverse bacterial communities, with special emphasis on utilizing the large number of sequences obtained (tens to hundreds of thousands) for species richness estimation. However, it is not yet clear how the number of operational taxonomic units (OTUs), and hence species richness estimates, determined using shorter fragments at different taxonomic cutoffs correlates with the number of OTUs assigned using longer, nearly complete 16S rRNA gene fragments. We constructed a 16S rRNA clone library from an undisturbed tall grass prairie soil (1132 clones), and used it to compare species richness estimates obtained using 8 pyrosequencing-c......
POSTED 06/25/2009 at 06:00 PM --
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Sulfur Isotope Enrichment during Maintenance Metabolism of the Thermophilic Sulfate Reducing Desulfotomaculum putei.
We examined the effect of extremely slow sulfate reduction rates and electron donor limitation on S isotope fractionation by culturing a thermophilic, sulfate reducing bacterium, Desulfotomaculum putei, in a biomass recycling culture vessel or "retentostat". The cell specific rate of sulfate reduction and the specific growth rate decreased progressively from the exponential phase to the maintenance phase yielding average maintenance coefficients of 10(-16) to 10(-18) molSO4 cell(-1) hr(-1) towards the end of the experiments. Overall S mass and isotopic balance were conserved during the experiment. The differences in the delta(34)S of the sulfate and sulfide eluting from retentostat were significantly larger, attaining a maximum Delta(34)S of -20.9 per thousand, than the -9.7 per thousand o......
POSTED 06/25/2009 at 06:00 PM --
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Widespread distribution of poribacteria in Demospongiae.
Authors: Lafi FF, Fuerst JA, Fieseler L, Hentschel U
Poribacteria were found in nine sponge species covering six orders of Porifera from three oceans. Phylogenetic analysis revealed four distinct poribacterial clades, which contained members from several different geographic regions, indicating cosmopolitan distribution. Divergent poribacteria clade members were also found in the same sponge species in three different sponge genera.
PMID: 19561181 [PubMed - as supplied by publisher] (Source: Applied and Environmental Microbiology)...
POSTED 06/25/2009 at 06:00 PM --
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RNA-colony blot hybridization method for enumeration of culturable Vibrio cholerae and Vibrio mimicus.
Authors: Grim CJ, Zo YG, Hasan NA, Ali A, Chowdhury WB, Islam A, Rashid MH, Alam M, Morris JG, Huq A, Colwell RR
A species-specific RNA colony blot hybridization protocol was developed for enumeration of culturable V. cholerae and V. mimicus in environmental water samples. Bacterial colonies on selective or non-selective plates were lysed by SDS and the lysates were immobilized on nylon membranes. A fluorescence-labeled oligonucleotide probe targeting a phylogenetic signature sequence of 16S rRNA of V. cholerae and V. mimicus was hybridized to rRNA molecules immobilized on the nylon colony lift blots. The protocol produced strong positive signals for all colonies of the 15 diverse V. cholerae-V. mimicus strains tested, indicating 100% sensitivity of the probe for the targeted species. ......
POSTED 06/25/2009 at 06:00 PM --
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Dead-end Hollow Fiber Ultrafiltration for Recovery of Diverse Microbes in Water.
Authors: Smith CM, Hill VR
Dead-end UF (DEUF) is an alternative approach to tangential-flow hollow-fiber ultrafiltration that can be readily employed under field conditions to recover microbes from water. The hydraulics of DEUF and microbe recovery for a new DEUF method were investigated using 100-L tap water samples. Pressure, flow rate, and temperature were investigated using four hollow fiber ultrafilter types. Based on hydraulic performance, the Asahi Kasei REXEED 25S ultrafilter was selected for microbe recovery experiments. Microbe recovery experiments were performed using MS2 bacteriophage, Enterococcus faecalis, Clostridium perfringens spores, and Cryptosporidium parvum oocysts. Microbes were recovered from ultrafilters by backflushing using a surfactant solution. Average flow ......
POSTED 06/25/2009 at 06:00 PM --
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