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Physiological Understanding (physiological + understanding)
Selected AbstractsGluconeogenesis in Candida albicansFEMS YEAST RESEARCH, Issue 3 2002D. Eschrich Abstract According to different metabolic situations in various stages of Candida albicans pathogenesis the regulation of carbohydrate metabolism was investigated. We report the genetic characterization of all major C. albicans gluconeogenic and glyoxylate cycle genes (fructose-1,6-bisphosphatase, PEP carboxykinase, malate synthase and isocitrate lyase) which were isolated after functional complementation of the corresponding Saccharomyces cerevisiae deletion mutants. Remarkably, the regulation of the heterologously expressed C. albicans gluconeogenic and glyoxylate cycle genes was similar to that of the homologous S. cerevisiae genes. A C. albicans,Cafbp1 deletion strain failed to utilize non-fermentable carbon sources but hyphal growth was not affected. Our results show that regulation of gluconeogenesis in C. albicans is similar to that of S. cerevisiae and that the current knowledge on how gluconeogenesis is regulated will facilitate the physiological understanding of C. albicans. [source] Lichen acclimatization on retention trees: a conservation physiology lessonJOURNAL OF APPLIED ECOLOGY, Issue 4 2009Kadi Jairus Summary 1.,Green-tree retention (GTR) has been suggested as a means to effectively support epiphytic lichen species in managed forests, given the low lichen mortality on retention trees in the short term. However, a long-term perspective requires a physiological understanding of lichen responses to logging. This study compares anatomical, morphological and physiological traits of lichens on retention trees and on intact forest trees. 2.,Thalli of nine taxa (Buellia griseovirens, Cladonia digitata, Hypogymnia physodes, Lecanora allophana, Lecanora pulicaris, Lepraria spp., Peltigera praetextata, Pertusaria amara and Phlyctis argena) were sampled from birch Betula spp. and aspen Populus tremula in GTR cuts, where they had previously been reported to survive well, and in adjacent managed forests. In the laboratory, chlorophyll fluorescence parameter Fv/Fm, thickness of the upper cortex, photobiont to mycobiont ratio and (in Lecanora species) the relative area of the apothecia were measured. 3.,All the lichen samples collected from GTR cuts appeared alive, but their Fv/Fm was significantly lower, relative areas of the apothecia were larger and the upper cortices of thalli were thicker compared with the samples from adjacent forests. No difference in photobiont to mycobiont ratio was found. These patterns were broadly consistent among species, indicating a common mechanism: while suffering from photoinhibition, the lichens had acclimatized to the open conditions and increased their investment to sexual reproduction in a few years. 4.,Synthesis and applications. The study highlights the value of a morpho-physiological framework for conservation management by pointing out that, in GTR areas, lichen survival is high-irradiation limited and heavily dependent on phenotypic plasticity. A thin upper cortex may be a common feature of the most sensitive species. To sustain epiphyte populations in managed forests, precautionary harvesting strategies (gradual felling; group-retention; extended rotations) should be preferred and large-enough populations should be preserved, even though short-term studies suggest a high survival of lichens in cut areas. [source] Some highlights of research on aging with invertebrates, 2006,2007AGING CELL, Issue 5 2007Linda Partridge Summary The invertebrate model organisms continue to be engines of discovery in aging research. Recent work with Drosophila stem cells has thrown light on their human equivalents, and on the role of stem cells and their niches in the decline in fecundity with age. Inspired by observations of aging in bacteria and yeast, a new theoretical study has revealed evolutionary forces that could favour asymmetry in the distribution of damaged cell constituents at division, and hence pave the way for the evolution of aging and selective maintenance of integrity of the germ line. Mechanisms of nutrient sensing and cell signalling in the response of lifespan to dietary restriction have been elucidated. Powerful invertebrate models of human aging-related disease have been produced, and used to start to understand how the aging process acts as a risk factor for disease. In the near future, studies of invertebrate aging are likely to move away from an exclusive reliance on genetic manipulation towards a more biochemical and physiological understanding of these systems. [source] John Thelwall and the Politics of SympathyLITERATURE COMPASS (ELECTRONIC), Issue 9 2010Mary Fairclough John Thelwall's diverse achievements in the fields of literature, science and politics have been read as the reason for his omission from the Romantic literary canon. But Thelwall's scientific research arms him with a unique understanding of the connections between these disciplines, which upset the very notion of canonicity. Thelwall's model of sympathy, developed in his Essay Towards a Definition of Animal Vitality (1791) offers a physiological understanding of the term which he applies to radical effect in his literary and political works. For Thelwall, sympathy is the physical force through which one organ of the body is inextricably connected with the rest. This physical model radicalises the sentimental tropes Thelwall employs in The Peripatetic (1793), where benevolence is figured as an instinctive impulse. In Thelwall's political lectures, sympathy is an index of solidarity, but its rational, material basis offers a riposte to charges that Thelwall seeks to exploit the unruly energies of his audience. Thelwall figures sympathy instead as the medium for his political ideal, the diffusion of information and ideas. [source] The seminal fluid proteome of the honeybee Apis melliferaPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2009Boris Baer Dr. Abstract Ejaculates contain sperm but also seminal fluid, which is increasingly recognized to be of central importance for reproductive success. However, a detailed biochemical composition and physiological understanding of seminal fluid is still elusive. We have used MS to identify the 57 most abundant proteins within the ejaculated seminal fluid of the honeybee Apis mellifera. Their amino acid sequences revealed the presence of diverse functional categories of enzymes, regulators and structural proteins. A number have known or predicted roles in maintaining sperm viability, protecting sperm from microbial infections or interacting with the physiology of the female. A range of putative glycoproteins or glycosylation enzymes were detected among the 57, subsequent fluorescent staining of glycolysation revealed several prominant glycoproteins in seminal fluid, while no glycoproteins were detected in sperm samples. Many of the abundant proteins that accumulate in the seminal fluid did not contain predictable tags for secretion for the cell. Comparison of the honeybee seminal fluid proteins with Drosophila seminal fluid proteins (including secreted accessory gland proteins known as ACPs), and with the human seminal fluid proteome revealed the bee protein set contains a range of newly identified seminal fluid proteins and we noted more similarity of the bee protein set with the current human seminal fluid protein set than with the known Drosophila seminal fluid proteins. The honeybee seminal fluid proteome thus represents an important addition to available data for comparative studies of seminal fluid proteomes in insects. [source] | ||||||||||