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Predominant Population (predominant + population)
Selected AbstractsGlutamate dehydrogenase activity in lactobacilli and the use of glutamate dehydrogenase-producing adjunct Lactobacillus spp. cultures in the manufacture of cheddar cheeseJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006A.G. Williams Abstract Aims:, The study was undertaken to investigate the occurrence of glutamate dehydrogenase activity in different species of lactobacilli, and to determine, in a series of cheese-making trials, the effects of glutamate dehydrogenase-producing adjunct cultures on sensory attribute development during the maturation of cheddar cheese. Methods and Results:, The presence of dehydrogenase activity with glutamate as substrate was monitored in cell lysates of >100 strains from 30 different species of lactobacilli using a qualitative colorimetric plate screening assay. Activity was detectable in 25 of the 29 representative species obtained from culture collections and in 12 of the 13 non-starter species isolated from cheese. There were pronounced interspecies and strain differences in the occurrence, level and pyridine nucleotide specificity of the glutamate dehydrogenase activity detected. Among the non-starter lactobacilli the highest frequency of enzyme occurrence and activity was detected in the Lactobacillus plantarum isolates. The establishment of glutamate dehydrogenase-producing adjunct strains in the predominant population of lactobacilli in the cheese curd affected the formation of a number of volatile compounds in ripening cheddar cheese, while the presence of Lact. plantarum strains, in particular, was associated with an intensification and acceleration of aroma and flavour development during the maturation period. Conclusions:, Glutamate dehydrogenase formation by lactobacilli is a strain-dependent metabolic attribute, and adjunct cultures expressing the activity that are able to proliferate during cheese ripening have a positive impact on the rate of development and the intensity of cheddar cheese aroma and flavour development. Significance and Impact of the Study:, It has been demonstrated that some strains of glutamate dehydrogenase-producing lactobacilli have potential use as adjunct cultures to accelerate and intensify aroma and flavour formation during the manufacture of cheddar and, by analogy, other similar varieties of cheese. The importance of phenotypic discriminative monitoring of the dominant lactobacilli present during ripening to confirm adjunct establishment and population complexity was highlighted as was the requirement to establish the metabolic attributes of the non-starter population in uninoculated control cheeses in comparative trials. [source] Gamma/delta T cells are the predominant source of interleukin-17 in affected joints in collagen-induced arthritis, but not in rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 8 2009Yoshinaga Ito Objective Although interleukin-17 (IL-17),producing ,/, T cells were reported to play pathogenic roles in collagen-induced arthritis (CIA), their characteristics remain unknown. The aim of this study was to clarify whether ,/, T cells or CD4+ T cells are the predominant IL-17,producing cells, and to determine what stimulates ,/, T cells to secret IL-17 in mice with CIA. The involvement of IL-17,producing ,/, T cells in SKG mice with autoimmune arthritis and patients with rheumatoid arthritis (RA) was also investigated. Methods IL-17,producing cells in the affected joints of mice with CIA were counted by intracellular cytokine staining during 6 distinct disease phases, and these cells were stimulated with various combinations of cytokines or specific antigens to determine the signaling requirements. Similar studies were performed using SKG mice with arthritis and patients with RA. Results Gamma/delta T cells were the predominant population in IL-17,producing cells in the swollen joints of mice with CIA, and the absolute numbers of these cells increased in parallel with disease activity. IL-17,producing ,/, T cells expressed CC chemokine receptor 6, were maintained by IL-23 but not by type II collagen in vitro, and were induced antigen independently in vivo. Furthermore, IL-17 production by ,/, T cells was induced by IL-1, plus IL-23 independently of T cell receptor. In contrast to what was observed in mice with CIA, IL-17,producing ,/, T cells were nearly absent in the affected joints of SKG mice and patients with RA, and Th1 cells were predominant in the joints of patients with RA. Conclusion Gamma/delta T cells were antigen independently stimulated by inflammation at affected joints and produced enhanced amounts of IL-17 to exacerbate arthritis in mice with CIA but not in SKG mice with arthritis or patients with RA. [source] Epidemiology of irritable bowel syndrome in Asia: Something old, something new, something borrowedJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2009Kok-Ann Gwee Abstract In this review we have unearthed epidemiological data that; support the ,old' concept of irritable bowel syndrome (IBS) as a disorder of civilization, build a ,new' symptom profile of IBS for Asia, and persuade us against the use of ,borrowed' Western diagnostic criteria and illness models by Asian societies. In the 1960s, IBS was described as a disorder of civilization. Early studies from Asia suggested a prevalence of IBS below 5%. Recent studies from Asia suggest a trend for the more affluent city states like Singapore and Tokyo, to have higher prevalence of 8.6% and 9.8%, respectively, while India had the lowest prevalence of 4.2%. Furthermore, there was a trend among the better educated and more affluent strata of society in several urban Chinese populations for a higher prevalence of IBS, as well as a trend for a higher consultation rate. Across Chinese and Indian predominant populations, a majority of patients with IBS criteria report upper abdominal symptoms such as epigastric pain relieved by defecation, bloating and dyspepsia. Bloating and incomplete evacuation appear to be more important determinants of consultation behavior, than psychological factors. The failure of the Rome criteria to recognize the relationship to meals, may have led to a substantial misclassification of IBS as dyspepsia. The relevance of the Western model of psychological disturbance as a determinant of consultation behavior is questionable because of the accessibility and acceptability of medical consultation for gastrointestinal complaints in many Asian communities. [source] Low-level plasma HIVs in patients on prolonged suppressive highly active antiretroviral therapy are produced mostly by cells other than CD4 T-cellsJOURNAL OF MEDICAL VIROLOGY, Issue 1 2009Gautam K. Sahu Abstract The cellular source(s) and the clinical significance of persistent low-level viremia, below 50 HIV RNA copies per ml of plasma, achieved in many patients with high adherence to highly active antiretroviral therapy (HAART) remain unclear. Also, it is not clear if residual plasma HIVs during HAART can become predominant populations in the rebounding plasma viral loads after therapy interruption. Since, different HIV quasispecies tend to compartmentalize in various cell types and tissue locations in patients during chronic infection, the phylogenetic relationships between HIV sequences amplified from residual plasma viruses and CD4 T cells of five patients on long-term suppressive therapy were examined. Three of these patients stopped therapy voluntarily for 3 weeks, but only one of them demonstrated viral load rebound in plasma. In phylogenetic analyses, the residual plasma viruses were found to be distinct genetically from the majority of CD4 T cell-associated virus populations in four of five patients. The compartmental analyses revealed that in all patients, plasma- and CD4 T cell-derived viral sequences were compartmentalized separately. Interestingly, the plasma sequences obtained before and after HAART-off in two patients were produced apparently from the same compartment, which was different from the circulating CD4 T cell-compartment. These results suggest the possibility that residual plasma viruses in patients on long-term suppressive HAART may be produced persistently from a cellular source yet to be identified, and are capable of spreading quickly in vivo, accounting for the rapid rebound of viral loads in plasma after therapy interruption. J. Med. Virol. 81:9,15, 2009. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||