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Same Strain (same + strain)
Selected AbstractsDisruption of nasopharyngeal epithelium by pneumococci is density-linkedEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2003K. Lagrou Abstract Background The aim of this project was to study the influence of pneumococci on nasopharyngeal epithelial integrity as a function of time and pneumococcal density. Materials and methods Cell layers of an in vitro model of human nasopharyngeal epithelium were inoculated with different pneumococcal strains. The transepithelial electrical resistance (TEER), a measure of the integrity of the cell layers, and the pneumococcal concentration in the apical fluid on the epithelial cells were measured at different times after inoculation. Results Pneumococci caused a decrease in the TEER when a density of 1 × 107 CFU mL,1 was reached. The growth rate of pneumococci in our in vitro model differed between the strains tested and, for the same strain, between in vitro culture on the epithelial cells and broth culture. Differences in timing of the onset of decrease in the TEER between strains were the result of differences in growth rate on the epithelial cells. Antibiotic-induced lysis of pneumococci caused an immediate decrease in the TEER of the cell layers. Conclusion Pneumococci cause a decrease in the TEER at a density of 1 × 107 CFU mL,1. Our hypothesis is that this decrease in the TEER is the result of quorum-induced lysis of the pneumococci. [source] Social and sexual incentive properties of estrogen receptor ,, estrogen receptor ,, or oxytocin knockout miceGENES, BRAIN AND BEHAVIOR, Issue 1 2008A. Ågmo Social and sexual incentive motivation, defined as the intensity of approach to a social and a sexual incentive, respectively, were studied in female Swiss Webster mice. In the first experiment, the social incentive was a castrated mouse of the same strain as the females, whereas the sexual incentive was an intact male mouse of the same strain. Ovariectomized females were first tested after oil treatment and then after administration of estradiol benzoate + progesterone in doses sufficient to induce full receptivity. The hormones increased sexual incentive motivation while leaving social incentive motivation unaffected. This suggests that sexual incentive motivation in the female mouse is dependent on ovarian hormones. In the next experiment, ovariectomized females were tested with an intact, male estrogen receptor , knockout and its wild type as incentives, first without hormones and then when fully receptive. There were no differences in incentive properties between the wild type and the knockout. In a similar experiment, we used an intact male estrogen receptor , knockout and its corresponding wild type as incentives. The wild type turned out to be a more attractive social incentive than the knockout, while they were equivalent as sexual incentives. Finally, an intact male oxytocin knockout and its wild type were used as incentives. The knockout turned out to be a superior incentive, particularly a superior sexual incentive. The fact that the estrogen receptor , and oxytocin knockouts have incentive properties different from their wild types may be important to consider in studies of these knockouts' sociosexual behaviors. [source] Immunological basis of the development of necrotic lesions following Mycobacterium avium infectionIMMUNOLOGY, Issue 4 2002Manuela Flórido Summary Normal C57BL/6 mice infected with 106 colony-forming units of a highly virulent strain of Mycobacterium avium developed a progressive infection characterized by loss of T cells from the tissues and infiltration with high numbers of heavily infected macrophages. In contrast, when C57BL/6 mice were infected with 102 colony-forming units of the same strain they retained T cells and T-cell reactivity in the tissues, and granulomas evolved into large masses that, at 4 months of infection, exhibited central necrosis. The development of these necrotic lesions did not occur in nude mice, nor in mice genetically deficient in CD4, interleukin-12 (IL-12) p40, interferon-, (IFN-,) and CD40 and were reduced in mice deficient in CD54 or IL-6. They were less numerous but bigger in mice deficient in IL-10 or the inducible nitric oxide synthase, correlating with the increased resistance to mycobacterial proliferation of these strains as compared to control mice. The appearance of necrosis was not affected in mice deficient in CD8,, T-cell receptor ,, tumour necrosis factor receptor p55, and perforin, nor was it affected in mice over-expressing bcl2. The appearance of necrosis could be prevented by administering antibodies specific for CD4, IL-12p40, or IFN-, from the second month of infection when organized granulomas were already found. Our results show that the immunological mediators involved in the induction of protective immunity are also major players in the immunopathology associated with mycobacteriosis. [source] Lyme borreliosis , an updateJOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 5 2007Elisabeth Aberer Summary Lyme borreliosis is the most common tick-borne, infectious disease in the northern hemisphere. Disease manifestations in the United States and Europe vary as a result of geographic distribution of different species within the genospecies Borrelia burgdorferi sensu lato, which in turn are host-specific. Certain toxigenic B. burgdorferi strains cause early disseminated disease. The ability of Borrelial organisms to break down the extracellular matrix also promotes dissemination. B. burgdorferi are eliminated by complement-mediated lysis and by T and B cell activity of the specific immune response. Yet, B. burgdorferi can evade humoral immunity by means of type of protective mechanism by which it adheres to the proteoglycan decorin in the joints and skin. A further factor in the persistence of the pathogen is altered antigen expression. Re-infection usually occurs with a different strain, although repeated infection with the same strain is also possible after a certain period of latency. New developments in serologic testing include the use of recombinant native antigen as well as antigens produced in vivo such as VlsE (variable major protein-like sequence, expressed) or decorin-binding protein A. Diagnosis continues to be complicated by seropositivity of healthy individuals, the persistence of antibodies after therapy, and a lacking humoral immune response in patients with erythema migrans. [source] Melt spun thermoresponsive shape memory fibers based on polyurethanes: Effect of drawing and heat-setting on fiber morphology and propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Jasmeet Kaursoin Abstract Thermoresponsive shape memory (SMP) fibers were prepared by melt spinning from a polyester polyol-based polyurethane shape memory polymer (SMP) and were subjected to different postspinning operations to modify their structure. The effect of drawing and heat-setting operations on the shape memory behavior, mechanical properties, and structure of the fibers was studied. In contrast to the as-spun fibers, which were found to show low stress built up on straining to temporary shape and incomplete recovery to the permanent shape, the drawn and heat-set fibers showed significantly higher stresses and complete recovery. The fibers drawn at a DR of 3.0 and heat-set at 100°C gave stress values that were about 10 times higher than the as-spun fibers at the same strain and showed complete recovery on repeated cycling. This improvement was likely due to the transformation brought about in the morphology of the permanent shape of the SMP fibers from randomly oriented weakly linked regions of hard and soft segments to the well-segregated, oriented and strongly H-bonded regions of hard-segments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2172,2182, 2007 [source] Mouse embryonic fibroblast cells from transgenic mice overexpressing tNOX exhibit an altered growth and drug response phenotypeJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2007Kader Yagiz Abstract Mouse embryonic fibroblast (MEF) cells prepared from transgenic mice overexpressing a cancer-specific and growth-related cell surface NADH oxidase with protein disulfide-thiol interchange activity grew at rates approximately twice those of wild-type embryonic fibroblast cells. Growth of transgenic MEF cells overexpressing tNOX was inhibited by low concentrations of the green tea catechin (,)-epigallocatechin-3-gallate (EGCg) or the synthetic isoflavene phenoxodiol. Both are putative tNOX-targeted inhibitors with anti-cancer activity. With both EGCg and phenoxodiol, growth inhibition was followed after about 48 h by apoptosis. Growth of wild-type mouse fibroblast cells from the same strain was unaffected by EGCg and phenoxodiol and neither compound induced apoptosis even at concentrations 100,1,000-fold higher than those that resulted in apoptotic death in the transgenic MEF cells. The findings validate earlier reports of evidence for tNOX presence as contributing to unregulated growth of cancer cells as well as the previous identification of the tNOX protein as the molecular target for the anti-cancer activities attributed to both EGCg and phenoxodiol. The expression of tNOX emerges as both necessary and sufficient to account for the cancer cell-specific growth inhibitions by both EGCg and phenoxodiol. J. Cell. Biochem. 101: 295,306, 2007. © 2006 Wiley-Liss, Inc. [source] The growth hormone receptor gene-disrupted mouse fails to respond to an intermittent fasting dietAGING CELL, Issue 6 2009Oge Arum Summary The interaction of longevity-conferring genes with longevity-conferring diets is poorly understood. The growth hormone receptor gene-disrupted (GHR-KO) mouse is long lived; and this longevity is not responsive to 30% caloric restriction, in contrast to wild-type animals from the same strain. To determine whether this may have been limited to a particular level of dietary restriction, we subjected GHR-KO mice to a different dietary restriction regimen, an intermittent fasting diet. The intermittent fasting diet increased the survivorship and improved insulin sensitivity of normal males, but failed to affect either parameter in GHR-KO mice. From the results of two paradigms of dietary restriction, we postulate that GHR-KO mice would be resistant to any manner of dietary restriction; potentially due to their inability to further enhance insulin sensitivity. Insulin sensitivity may be a mechanism and/or a marker of the lifespan extending potential of an intervention. [source] Analyses of amino acid sequences in hypervariable region-1 of hepatitis C virus (HCV) in sera from chimpanzees infected three times with the same HCV strainJOURNAL OF MEDICAL PRIMATOLOGY, Issue 1 2010M. Sugitani Abstract Background, To investigate whether or not the same strain of hepatitis C virus (HCV) can twice re-infect the same chimpanzee, we analyzed nucleic and amino acid sequences in HCV hypervariable region-1 (HVR1). Two chimpanzees were inoculated, three times each, with the same HCV strain during the 1983,1991. After each inoculation, chimpanzees developed acute hepatitis C, and then recovered. Methods, Using sera, HVR1 cloning and antibody to HVR1 major clone measurement were performed. Results, Clones from the first inoculum were divisible into major and minor types. Clones from the second and third inocula, as well as all post-inoculation sera, were essentially identical to the major type. Titers of antibody to HVR1 major clone were consistently low in pre- and post-inoculation sera. Conclusions, Both chimpanzees were re-infected twice with the same strain of HCV. The sequences from the second and third infections were similar to the major sequences in the first inoculum. [source] Role of Potassium Channel Gene Kcnj10 in Ethanol Preference in C57bl/6J and DBA/2J MiceALCOHOLISM, Issue 3 2009Shicong B. Zou Background:, Inwardly-rectifying potassium channel protein Kir4.1 is encoded by Kcnj10 which maps to a quantitative trait locus on chromosome 1 for the voluntary alcohol consumption phenotype in mice. Kcnj10 brain expression differences have been established between ethanol-preferring C57Bl/6J and ethanol-avoiding BALB/cJ mice, but its differential expression in other tissues and strains have largely been overlooked. A nonsynonymous single nucleotide polymorphism exists between C57Bl/6J and ethanol-avoiding DBA/2J mice which changes amino acid 262 from threonine (C57Bl/6J) to serine (DBA/2J). This Kcnj10 SNP and its expression may serve as valuable markers in predicting the ethanol preference phenotype in mice. Methods:, The evolutionary divergence of the Kir gene family was characterized using phylogenetic analysis involving the 16 mouse Kir channels. Kcnj10 expression differences in the brain, liver, lung, heart, spleen, kidney, testes, and muscle of male C57Bl/6J and DBA/2J mice at different developmental stages were examined using semiquantitative RT-PCR analysis. A SNP analysis was conducted to assess the association of Kcnj10 Thr262Ser SNP and the ethanol preference phenotype in F2 mice derived from the reciprocal crosses of the C57Bl/6J and DBA/2J strains. Results:, Evolutionary analysis supports gene duplication and genetic recombination as likely sources of diversity within the Kir gene family. Semiquantitative RT-PCR analysis revealed significantly higher Kcnj10 expression in the brain, spleen, and kidney of both strains when compared to other tissues from the same strain. There were no significant differences in tissue-specific mRNA levels between strains except in the testes. Genotype distributions of the Kcnj10 Thr262Ser SNP were different between low- and high-drinkers. A significant difference in the average ethanol preference level of each genotype was also observed. Conclusion:, Our results suggest a role for Kcnj10 in ethanol preference determination in mice. However, further experiments are needed to establish if this association is due to the nonsynonymous SNP or other additional factors associated with Kcnj10. [source] Prevalence of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus Carriage in Three PopulationsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010S. Kottler Background: A higher prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization is reported in healthcare workers compared with nonhealthcare workers. Hypothesis: The prevalence of MRSA colonization differed in people and pets in households with healthcare workers as compared with households without healthcare workers. Subjects: A person and 1 dog or cat from 586 households defined as either a nonhealthcare (n = 213), veterinary healthcare (n = 211), or human healthcare (n = 162) worker household. Methods: Prospective cross-sectional study. Samples from humans and pets were cultured in vitro. Staphylococcus aureus was identified as methicillin sensitive (MSSA) or MRSA with mecA polymerase chain reaction. Pulsed-field gel electrophoresis and spa -typing were used to characterize relatedness of S. aureus and MRSA and assign USA types. Results: The prevalence of MSSA and MRSA in humans was 21.5% (126/586) and 5.63% (33/586), respectively, and 7.85% (46/586) and 3.41% (20/586), respectively, in pets. There were no differences in prevalences of either MSSA or MRSA between household types. The proportion of MRSA among all S. aureus isolates in humans and pets was 20.8% (33/159) and 30.3% (20/66), respectively. In <1.0% (4/586) of households, the same strain of MRSA was found in both a person and a pet. Conclusions and Clinical Importance: There were no differences in the prevalences of MSSA or MRSA between healthcare worker and nonhealthcare worker households. Pets and people colonized with S. aureus were as likely to be colonized with MRSA. Colonization of a person and their pet with the same strain of MRSA was rare. [source] Is the hepatitis C virus epidemic over in Egypt?LIVER INTERNATIONAL, Issue 4 2010Incidence, risk factors of new hepatitis C virus infections Abstract Objectives: To estimate hepatitis C virus (HCV) incidence rates and identify risk factors for current HCV transmission with emphasis on the role of living with infected household family members in rural Egypt. Methods: A 4-year population-based, cohort study of seronegative villagers was conducted to identify incident HCV seroconversion cases. A risk factor questionnaire and blood samples for anti-HCV EIA-3 and HCV RNA polymerase chain reaction testing were collected at two rounds of follow-up. Incidence rates, relative risks and 95% confidence interval (CI) were calculated based on a Poisson distribution. A matched case,control analysis to explore specific behavioural predictors of infection was conducted and odds ratios were obtained by conditional logistic regression. Results: Twenty-five participants (11 females) seroconverted in 10 578 person years of follow-up (PY), (incidence rate of 2.4/1000 PY; 95% CI: 1.6,3.5). The median age at seroconversion was 26 years [interquartile range (IQR) 19,35] among males and 20 years (IQR 13,24) among females. The only significant risk factor identified for these cases was receiving injections [adjusted odds ratio (ORadj)=3.3; 95% CI: 1.1,9.8]. Two of the 17 viraemic seroconvertors were infected with the same strain as at least one of their family members. Conclusion: This study identified the important role of injections in spreading HCV infection in this rural community. National healthcare awareness and infection control programmes should be strengthened to prevent further transmission. Screening of families of infected HCV subjects should be an essential part of case management for early detection and management. [source] Stimulation of DNA repair and increased light output in response to UV irradiation in Escherichia coli expressing lux genesLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2007Kerry L. Cutter Abstract It has previously been suggested that the evolutionary drive of bacterial bioluminescence is a mechanism of DNA repair. By assessing the UV sensitivity of Escherichia coli, it is shown that the survival of UV-irradiated E. coli constitutively expressing luxABCDE in the dark is significantly better than either a strain with no lux gene expression or the same strain expressing only luciferase (luxAB) genes. This shows that UV resistance is dependent on light output, and not merely on luciferase production. Also, bacterial survival was found to be dependent on the conditions following UV irradiation, as bioluminescence-mediated repair was not as efficient as repair in visible light. Moreover, photon emission revealed a dose-dependent increase in light output per cell after UV exposure, suggesting that increased lux gene expression correlates with UV-induced DNA damage. This phenomenon has been previously documented in organisms where the lux genes are under their natural luxR regulation but has not previously been demonstrated under the regulation of a constitutive promoter. Copyright © 2007 John Wiley & Sons, Ltd. [source] Inhibition of Actinobacillus actinomycetemcomitans leukotoxicity by bacteria from the subgingival floraMOLECULAR ORAL MICROBIOLOGY, Issue 4 2000A. Johansson Actinobacillus actinomycetemcomitans produces a pore-forming leukotoxin that lyses human polymorphonuclear leukocytes and monocytes. Certain proteolytic bacteria may coexist with A. actinomycetemcomitans in periodontal pockets. We aimed therefore to examine whether oral bacteria can modify the leukotoxicity of A. actinomycetemcomitans. A total of 55 strains representing 45 bacterial species of the subgingival flora were tested. Each strain was incubated with the highly toxic strain of A. actinomycetemcomitans HK 1519 and the leukotoxic activity of the suspension against human polymorphonuclear leukocytes was determined from the activity of the lactate dehydrogenase released upon lysis of the leukocytes. Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica and Prevotella loeschii inhibited the leukotoxicity of A. actinomycetemcomitans cells as well as the activity of leukotoxin purified from the same strain. The bacterial strains without the ability to block leukotoxic activity also failed to destroy pure leukotoxin even after 5 h of incubation. The proteolytic degradation of leukotoxin by P. gingivalis was mainly dependent on the activity of the enzymes R- and K-gingipains. P. intermedia and P. nigrescens also degraded the leukotoxin by enzymes. The results imply a role of the periodontal microflora in modifying the virulence of A. actinomycetemcomitans by destroying its leukotoxin. [source] Use of magnetic beads to extract fungal DNAMYCOSES, Issue 1 2005E. Faggi Summary Authors compare two methods of extracting DNA from different fungi: the classic method with phenol/chloroform (P/C) and that with magnetic beads. Both were tested on Candida albicans and Cryptococcus neoformans var. neoformans, belonging to the yeast group and Microsporum canis, M. gypseum, Trichophyton rubrum, T. interdigitale, T. ajelloi, Epidermophyton floccosum, belonging to the dermatophytes group. Extraction products underwent polymerase chain reaction (PCR) fingerprinting with the appropriate primers to point out any disagreement in the genomic profiles. After having determined that the genomic profiles obtained from the DNA extracted from the same strain with the two methods correspond perfectly, the authors concluded that the extraction method with magnetic beads from fungal cells is simpler and quicker than with P/C extraction, greatly facilitating the obtainment of fungal DNA. [source] Metabolism of fungicidal cyanooximes, cymoxanil and analogues in various strains of Botrytis cinereaPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2009Frédérique Tellier Abstract BACKGROUND: The metabolism of cymoxanil [1-(2-cyano-2-methoxyiminoacetyl)-3-ethylurea] and fungicidal cyanooxime analogues was monitored on three phenotypes of Botrytis cinerea Pers. ex Fr. differing in their sensitivity towards cymoxanil. For this purpose, labelled [2- 14C]cymoxanil was added either to the culture medium of these strains or to its cell-free extract. RESULTS: In the culture medium of the most sensitive strain, four main metabolites were detected. Three were isolated and identified. Cymoxanil was quickly metabolised by at least three concurrent enzymatic pathways: (i) cyclisation leading, after hydrolysis, to ethylparabanic acid, (ii) reduction giving demethoxylated cymoxanil, (iii) hydrolysis followed by reduction and then acetylation leading to N -acetylcyanoglycine. In the cell-free extract of the same strain, only the first and the second of these enzymatic reactions occurred. By comparing the metabolic profile of the most sensitive strain with that of the less sensitive ones, it was shown that the decrease in sensitivity to cymoxanil correlates with a reduced acetylcyanoglycine formation. Among all metabolites, only N -acetylcyanoglycine is active against the most sensitive strain. Moreover, in a culture of this strain, two other fungicidal cyanooximes were also metabolised into this metabolite. CONCLUSION: The formation of N -acetylcyanoglycine may play an important role in the fungitoxicity of cymoxanil and cyanooxime derivatives. Copyright © 2008 Society of Chemical Industry [source] Negative cross-resistance between dihydropyrazole insecticides and pyrethroids in houseflies, Musca domesticaPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2001Bhupinder P, S Khambay Abstract A series of insecticidal dihydropyrazoles and related compounds have been shown to exhibit negative cross-resistance to a resistant (super-kdr) strain of houseflies with site-insensitivity to pyrethroids. The level of cross-resistance is similar to that observed previously for a range of N -alkylamides against the same strain. © 2001 Society of Chemical Industry [source] Proteomic analysis of the response of an acidophilic strain of Chlamydomonas sp. (Chlorophyta) to natural metal-rich waterPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 10 2010Cristina Cid Abstract A proteomic approach including 2-DE and MALDI-TOF analysis has been developed to identify the soluble proteins of the unicellular photosynthetic algae Chlamydomonas sp. isolated from an extreme acidic environment, Río Tinto (southwest Spain). We have analyzed the soluble proteome obtained from whole cells growing on metal-rich natural acidic water from the river in comparison with the same strain growing in artificial BG-11 media. The most drastic effect was the decrease in the abundance of the ribulose-1,5-biphosphate carboxylase as well as other enzymes related to photosynthesis. However, phytochrome B, phosphoribulokinase, and phosphoglycerate kinase were upregulated when cells were grown in metal-rich acidic water. Besides, increased accumulation of two Hsps, Hsp70 and Hsp90 as well as other stress-related enzymes were also found in the cells growing in natural acidic water. These results suggest that naturally occurring metal-rich water induces a stress response in acidophilic Chlamydomonas forcing algal cells to reorganize their metabolic pathways as an adaptive response to these environmental conditions. [source] Influence of biofilm formation in the susceptibility of Pseudomonas aeruginosa from Brazilian patients with cystic fibrosisAPMIS, Issue 8 2010ALEX GUERRA FERREIRA Ferreira AG, Leão RS, Carvalho-Assef APD, Folescu TW, Barth AL, Marques EA. Influence of biofilm formation in the susceptibility of Pseudomonas aeruginosa from Brazilian patients with cystic fibrosis. APMIS 2010; 118: 606,12. Biofilms play a key role in the occurrence of lung infections by Pseudomonas aeruginosa in patients with cystic fibrosis (CF). In this study, we examined 40 isolates of P. aeruginosa from CF patients according to their capacity to form biofilm. We also compared their in vitro response to antimicrobials according to different modes of growth (planktonic vs biofilm) and performed molecular typing. All isolates proved capable of forming biofilm. However, there was no difference in biofilm development according to the mucoid and nonmucoid phenotypes and among isolates obtained at different periods of the chronic infection. All isolates tested for antimicrobial susceptibility in the biofilm state (BIC) were consistently more resistant to antibiotics than the same isolate tested in the planktonic state. The molecular typing indicates a considerable clonal diversity among isolates. We identified five patients harboring the same strain over different periods. These strains, however, displayed different levels of biofilm formation and BIC values for antibiotics tested. The results of the present study demonstrate that there is a marked difference in the susceptibility profile according to the mode of growth of CF P. aeruginosa, as cells tested in the biofilm state proved consistently more resistant to antibiotics. [source] Application of ERIC PCR for the comparison of isolates of Haemophilus parasuisAUSTRALIAN VETERINARY JOURNAL, Issue 12 2000M. RAFIEE Objective To validate a polymerase chain reaction (PCR) based method, Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), for the fingerprinting of Haemophilus parasuis strains and to use that method to differentiate isolates from apparently related outbreaks of Glässers disease on three pig farms. Design ERIC-PCR was evaluated by comparing 15 different strains that represented all 15 recognised serovars in the Kielstein-Rapp-Gabrielson (KRG) scheme for serotyping H parasuis. Next, ERIC-PCR was used to examine 14 Australian field isolates of H parasuis; 12 collected from three farms suffering apparently related outbreaks of Glässers disease and two from two other farms with no known connection. Results The 15 serovar reference strains all gave unique, reproducible ERIC-PCR fingerprints. The 12 isolates from the three apparently related outbreaks all gave a single fingerprint, which was distinct from any seen in the 15 serovar reference strains and the two other Australian field isolates in the studied farms. The confirmation that all 12 isolates were the same strain allowed the development of a prevention and control program that has prevented the emergence of any further outbreaks of Glässer disease on the three farms. Conclusion ERIC-PCR is a suitable technique for the differentiation of unrelated strains of H parasuis. The finding that the 12 field isolates of H parasuis all shared the same fingerprint is strong evidence that there was a common source of infection on all three farms. This study has shown, for the first time, that ERIC-PCR is a suitable technique for the sub-typing of H parasuis and useful for studying the epidemiology of outbreaks of Glässers disease. [source] Understanding and Improving NADPH-Dependent Reactions by Nongrowing Escherichia coli CellsBIOTECHNOLOGY PROGRESS, Issue 2 2004Adam Z. Walton We have shown that whole Escherichia coli cells overexpressing NADPH-dependent cyclohexanone monooxygenase carry out a model Baeyer-Villiger oxidation with high volumetric productivity (0.79 g ,-caprolactone/L·h ) under nongrowing conditions (Walton, A. Z.; Stewart, J. D. Biotechnol. Prog.2002, 18, 262,268). This is approximately 20-fold higher than the space-time yield for reactions that used growing cells of the same strain. Here, we show that the intracellular stability of cyclohexanone monooxygenase and the rate of substrate transport across the cell membrane were the key limitations on the overall reaction duration and rate, respectively. Directly measuring the levels of intracellular nicotinamide cofactors under bioprocess conditions suggested that E. coli cells could support even more efficient NADPH-dependent bioconversions if a more suitable enzyme-substrate pair were identified. This was demonstrated by reducing ethyl acetoacetate with whole cells of an E. coli strain that overexpressed an NADPH-dependent, short-chain dehydrogenase from bakerapos;s yeast ( Saccharomyces cerevisiae). Under glucose-fed, nongrowing conditions, this reduction proceeded with a space-time yield of 2.0 g/L·h and a final product titer of 15.8 g/L using a biocatalyst:substrate ratio (g/g) of only 0.37. These values are significantly higher than those obtained previously. Moreover, the stoichiometry linking ketone reduction and glucose consumption (2.3 ± 0.1) suggested that the citric acid cycle supplied the bulk of the intracellular NADPH under our process conditions. This information can be used to improve the efficiency of glucose utilization even further by metabolic engineering strategies that increase carbon flux through the pentose phosphate pathway. [source] Is MRSA more virulent than MSSA?CLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2007F. Rozgonyi Abstract Numerous clinical studies have indicated, based on mortality rates, that methicillin-resistant Staphylococcus aureus (MRSA) strains are more virulent than methicillin-susceptible S. aureus (MSSA) strains. In contrast, quantitative laboratory examinations of the presence and magnitude of pathogenic mechanisms and virulence factors in strains of MRSA and MSSA have generated conflicting data. The most important reason for these conflicting results is probably the heterogeneic nature of the resistant population. A comparison of selected and congenic MRSA and MSSA sub-populations of the same strain is required to resolve this issue. [source] Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2005Associate Professor Dr Angel Angelov Abstract Fermentation of a prebiotic containing oat substrate with probiotic lactic acid bacteria and yeast strains is an intriguing approach for the development of new synbiotic functional products. This approach was applied in the present work by using pure and mixed microbial cultures to ferment a heat-treated oat mash. Results show that the strains studied were appropriate for oat fermentation and the process could be completed for 6,10 h depending on the strain. The viable cell counts achieved within this time were above the required levels of 106,107 cfu ml,1 for probiotic products. Both single lactic acid bacteria strains and mixed cultures of the same strains with yeast were found suitable for oat fermentation. However, the pure LAB cultures attributed better flavour and shelf life of the oat drinks. The content of the prebiotic oat component beta-glucan remained within 0.30,0.36% during fermentation and storage of the drinks obtained with each of the strains used. Thus, these products would contribute diet with the valuable functional properties of beta-glucan. Also, the viability of pure and mixed cultures in the oat products was good: levels of cell counts remained above the required numbers for probiotic products throughout the estimated shelf-life period. Copyright © 2005 Society of Chemical Industry [source] Inactivation of Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes on the surface of tomatoes by neutral electrolyzed waterLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2003M.A. Deza Abstract Aims:, To determine the efficacy of neutral electrolyzed water (NEW) in killing Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes, as well as nonpathogenic E. coli, on the surface of tomatoes, and to evaluate the effect of rinsing with NEW on the organoleptic characteristics of the tomatoes. Methods and Results:, The bactericidal activity of NEW, containing 444 or 89 mg l,1 of active chlorine, was evaluated over pure cultures (8·5 log CFU ml,1) of the above-mentioned strains. All of them were reduced by more than 6 log CFU ml,1 within 5 min of exposure to NEW. Fresh tomatoes were surface-inoculated with the same strains, and rinsed in NEW (89 mg l,1 of active chlorine) or in deionized sterile water (control), for 30 or 60 s. In the NEW treatments, independent of the strain and of the treatment time, an initial surface population of about 5 log CFU sq.cm,1 was reduced to <1 log CFU sq.cm,1, and no cells were detected in the washing solution by plating procedure. A sensory evaluation was conducted to ascertain possible alterations in organoleptic qualities, yielding no significant differences with regard to untreated tomatoes. Significance and Impact of the Study:, Rinsing in NEW reveals as an effective method to control the presence of E. coli O157:H7, S. enteritidis and L. monocytogenes on the surface of fresh tomatoes, without affecting their organoleptic characteristics. This indicates its potential application for the decontamination of fresh produce surfaces. [source] | |||||||||||||||||||||||||