Home About us Contact
|
Home About us Contact | ||
|
|
||
Special Relevance (special + relevance)
Selected AbstractsExported proteins in probiotic bacteria: adhesion to intestinal surfaces, host immunomodulation and molecular cross-talking with the hostFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2008Borja Sánchez Abstract The group of exported proteins of a bacterium are those proteins that are sorted from the cytoplasm to the bacterial surface or to the surroundings of the microorganism. In probiotic bacteria, these proteins are of special relevance because they might determine important traits such as adhesion to intestinal surfaces and molecular cross-talking with the host. Current knowledge about the presence and biological relevance of exported proteins produced by the main genera of probiotic bacteria in the gastrointestinal environment is reviewed in this minireview. As will be seen, some of these proteins are involved in host adhesion or are able to modify certain signalization pathways within host cells, whereas others are important for the physiology of probiotic bacteria in the gastrointestinal tract. [source] Ethanol synthesis from glycerol by Escherichia coli redox mutants expressing adhE from Leuconostoc mesenteroidesJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2010P.I. Nikel Abstract Aims:, Analysis of the physiology and metabolism of Escherichia coli arcA and creC mutants expressing a bifunctional alcohol-acetaldehyde dehydrogenase from Leuconostoc mesenteroides growing on glycerol under oxygen-restricted conditions. The effect of an ldhA mutation and different growth medium modifications was also assessed. Methods and Results:, Expression of adhE in E. coli CT1061 [arcA creC(Con)] resulted in a 1·4-fold enhancement in ethanol synthesis. Significant amounts of lactate were produced during micro-oxic cultures and strain CT1061LE, in which fermentative lactate dehydrogenase was deleted, produced up to 6·5 ± 0·3 g l,1 ethanol in 48 h. Escherichia coli CT1061LE derivatives resistant to >25 g l,1 ethanol were obtained by metabolic evolution. Pyruvate and acetaldehyde addition significantly increased both biomass and ethanol concentrations, probably by overcoming acetyl-coenzyme A (CoA) shortage. Yeast extract also promoted growth and ethanol synthesis, and this positive effect was mainly attributable to its vitamin content. Two-stage bioreactor cultures were conducted in a minimal medium containing 100 ,g l,1 calcium d -pantothenate to evaluate oxic acetyl-CoA synthesis followed by a switch into fermentative conditions. Ethanol reached 15·4 ± 0·9 g l,1 with a volumetric productivity of 0·34 ± 0·02 g l,1 h,1. Conclusions:,Escherichia coli responded to adhE over-expression by funnelling carbon and reducing equivalents into a highly reduced metabolite, ethanol. Acetyl-CoA played a key role in micro-oxic ethanol synthesis and growth. Significance and Impact of the Study:, Insight into the micro-oxic metabolism of E. coli growing on glycerol is essential for the development of efficient industrial processes for reduced biochemicals production from this substrate, with special relevance to biofuels synthesis. [source] Effects of timing and rate of N supply on leaf nitrogen status, grape yield and juice composition from Shiraz grapevines grafted to one of three different rootstocksAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2007B.P. HOLZAPFEL Abstract Yeast cells have a minimum N requirement to ferment a must through to dryness, so that grape N content (hence must N) becomes critical in meeting that prerequisite. Viticultural practices aimed at meeting that N requirement are of special relevance because interactions between rootstock and vineyard nitrogen supply strongly influence scion mineral nutrient status as well as shoot vigour, and via those processes, fruit composition. Such outcomes were investigated in a field trial involving Shiraz on three rootstocks viz. Teleki 5C, Schwarzmann and Ramsey. Five N supply regimes, varying from 0 to 80 kg/(haseason), were imposed through a drip-irrigation system during two periods (either flowering to veraison, or post-harvest to leaf-fall, or both) over three successive growing seasons. Post-harvest N supply increased scion leaf N and nitrate N concentrations at flowering for vines on Teleki 5C and Schwarzmann. By veraison, N recently applied in the flowering to veraison period elevated these indicators of N status in all vines on all rootstocks. Grape yields from vines on Teleki 5C and Schwarzmann were elevated by N supply after harvest, whereas juice soluble solids levels were lowered. Free amino acids in Shiraz juice were dominated by non-assimilable N, amounting to about 50% or more of the total free amino-N in the juice. Increasing N supply increased free amino acid concentrations in the juice of berries from vines on all rootstocks, but only vines on Schwarzmann derived any benefit from N supplied after harvest. The highest concentrations of free amino acids were measured in the berries from vines on Schwarzmann receiving 80 kg N/(ha.season). Of immediate practical relevance for N management of Shiraz grapevines on either Teleki 5C or Ramsey rootstocks, the minimum value for assimilable free amino-N concentration required to ferment a must through to dryness was not achieved if vineyard N application was limited to the post-harvest period. [source] The Interface Between Physical and Mental Health Problems and Medical Help Seeking in Children and Adolescents: A Research PerspectiveCHILD AND ADOLESCENT MENTAL HEALTH, Issue 4 2004M. Elena Garralda This paper addresses child and adolescent psychopathology as it presents to general practitioners and paediatricians, and explores psychosocial aspects of unexplained medical symptoms in children and adolescents. High rates of psychopathology have been identified amongst children and adolescents attending general practice and paediatric services, most of it ,,hidden'' at presentation and emotional in nature. It is often linked to poor physical well being and to maternal stress focused on the child. It may be of special relevance to medical help seeking in socio-economically advantaged areas. Co-morbid psychopathology, mainly emotional disorders, is common amongst children with unexplained medical symptoms. However, there are specific psychosocial aspects that differentiate these children from those with emotional disorders. They involve disease beliefs, illness behaviour and predicament. The latter may be characterised by special reactivity to stress in children with personality vulnerability, in a context of parents with high levels of mental distress, unexplained medical symptoms and emotional over-involvement with the child. There is comparatively little interface work between CAMHS and primary health care. An important research priority would seem to lie in the development of interventions that can be adapted for use by primary care staff. Similarly, there are few dedicated CAMHS paediatric liaison teams. Their more extensive development should help attend in a more informed and focused way than at present to children and adolescents suffering from unexplained physical symptoms and disorders. Further research is needed into vulnerability mechanisms and maintaining factors, health beliefs, treatment engagement and interventions. [source] The Legacy of Child Development's 1990 Special Issue on Minority Children: An Editorial RetrospectiveCHILD DEVELOPMENT, Issue 5 2006Vonnie C. McLoyd Sixteen years have passed since the publication of Child Development's Special Issue on Minority Children. It is suggested that the most critical legacy of the special issue is the conceptual and ideological zeitgeist it fostered. The issue set culture and ecological context in the foreground of analyses, advanced a cultural-variant perspective, and further discredited the deficit perspective that long dominated the study of ethnic minority children and families. The special issue is also significant for its role in shaping post-1990 research agenda. In addition, it underscored the need for more nuanced articulations of what cultural or ethnic characteristics are of special relevance for understanding specific domains of development and the need for well-crafted methodological tools with which to test these ideas. [source] | ||||||||||