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Margarethe Spindler-Barth 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1976,105(2):197-205
Juvenile and young adult specimens ofCarcinus maenas were kept in the laboratory under controlled conditions. The main organic constituents and their variations during the molt cycle were quantitatively determined.
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1. | During postmolt the chitin concentration rises rapidly (20–74 mg/g dry weight) in parallel to the dry weight (120–293 mg/g fresh weight). Both decrease again before ecdysis (Fig. 1). |
2. | The glycose level in the hemolymph (50–80 g/ml) shows no significant variation during the molt cycle (Fig. 2). |
3. | The glycogen concentrations in integument, (14–180 mg/g dry weight), gills (5.5–66 mg/g dry weight), muscle (8.8–41 mg/g dry weight), heart (135–308 mg/g dry weight) and hemolymph (160–690 g/ml) reach their maximum values during the premolt stage. The highest glycogen content in the midgut gland (83 mg/g dry weight) is observed immediately before and after ecdysis. Glycogen storage in heart and hemolymph, can, account for about half of the glycogen stored in the midgut gland (Figs. 3,4 and 5). |
4. | The lipid concentration in the hemolymph (120–440 g/ml) and in gills (33.6–70 mg/g dry weight) rises during the premolt stage (Figs. 6 and 7). |
5. | The protein concentration in the hemolymph increased during premolt (9–31 mg/ml). The copper content (13–42 g/ml) varies in parallel to the protein concentration indicating that the proportion of hemocyanin to total proteins remains constant during the molting cycle (Fig. 8). |
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Background
The number of patients seeking health care is a central indicator that may serve several different purposes: (1) as a proxy for the impact on the burden of the primary care system; (2) as a starting point to estimate the number of persons ill with influenza; (3) as the denominator data for the calculation of case fatality rate and the proportion hospitalized (severity indicators); (4) for economic calculations. In addition, reliable estimates of burden of disease and on the health care system are essential to communicate the impact of influenza to health care professionals, public health professionals and to the public.Methodology/Principal Findings
Using German syndromic surveillance data, we have developed a novel approach to describe the seasonal variation of medically attended acute respiratory infections (MAARI) and estimate the excess MAARI attributable to influenza. The weekly excess inside a period of influenza circulation is estimated as the difference between the actual MAARI and a MAARI-baseline, which is established using a cyclic regression model for counts. As a result, we estimated the highest ARI burden within the last 10 years for the influenza season 2004/05 with an excess of 7.5 million outpatient visits (CI95% 6.8–8.0). In contrast, the pandemic wave 2009 accounted for one third of this burden with an excess of 2.4 million (CI95% 1.9–2.8). Estimates can be produced for different age groups, different geographic regions in Germany and also in real time during the influenza waves. 相似文献6.
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Przibilla S Hitchcock WW Szécsi M Grebe M Beatty J Henrich VC Spindler-Barth M 《Biological chemistry》2004,385(1):21-30
The functional insect ecdysteroid receptor is comprised of the ecdysone receptor (EcR) and Ultraspiracle (USP). The ligand-binding domain (LBD) of USP was fused to the GAL4 DNA-binding domain (GAL4-DBD) and characterized by analyzing the effect of site-directed mutations in the LBD. Normal and mutant proteins were tested for ligand and DNA binding, dimerization, and their ability to induce gene expression. The presence of helix 12 proved to be essential for DNA binding and was necessary to confer efficient ecdysteroid binding to the heterodimer with the EcR (LBD), but did not influence dimerization. The antagonistic position of helix 12 is indispensible for interaction between the fusion protein and DNA, whereas hormone binding to the EcR (LBD) was only partially reduced if fixation of helix 12 was disturbed. The mutation of amino acids, which presumably bind to a fatty acid evoked a profound negative influence on transactivation ability, although enhanced transactivation potency and ligand binding to the ecdysteroid receptor was impaired to varying degrees by mutation of these residues. Mutations of one fatty acid-binding residue within the ligand-binding pocket, 1323, however, evoked enhanced transactivation. The results confirmed that the LBD of Ultraspiracle modifies ecdysteroid receptor function through intermolecular interactions and demonstrated that the ligand-binding pocket of USP modifies the DNA-binding and transactivation abilities of the fusion protein. 相似文献
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Ligand binding to ecdysone receptor (EcR) is an autonomous function of the ligand binding domain (LBD) and is not modified by other receptor domains or tags fused to the LBD. Association and dissociation velocity of hormone to EcR was studied in the absence and presence of its main dimerization partner Ultraspiracle (USP). Mutational analysis of the EcR(LBD) revealed that ligand entry and exit is affected differently by the same point mutation, indicating that different pathways are used for association and dissociation of the ligand. Heterodimerization with wild type USP(LBD) increases ligand association to EcR(LBD) about fivefold and reduces dissociation 18-fold. Opposite effects of the same mutation (N626K) on dissociation velocity of ligand in EcR and EcR/USP indicate that not only hormone binding itself, but also the kinetic behaviour of ligand binding is modified by the dimerization partner. A general effect of the point mutations on the 3D architecture seems unlikely due to the highly selective effects on the kinetics of hormone binding. 相似文献
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Vander Heiden MG Choy JS VanderWeele DJ Brace JL Harris MH Bauer DE Prange B Kron SJ Thompson CB Rudin CM 《The Journal of biological chemistry》2002,277(47):44870-44876
All eukaryotic organisms have mechanisms to adapt to changing metabolic conditions. The mammalian cell survival gene Bcl-x(L) enables cells to adapt to changes in cellular metabolism. To identify genes whose function can be substituted by Bcl-x(L) in a unicellular eukaryote, a genetic screen was performed using the yeast Saccharomyces cerevisiae. S. cerevisiae grows by anaerobic glycolysis when glucose is available, switching to oxidative phosphorylation when carbohydrate in the media becomes limiting (diauxic shift). Given that Bcl-x(L) appears to facilitate the switch from glycolytic to oxidative metabolism in mammalian cells, a library of yeast mutants was tested for the ability to efficiently undergo diauxic shift in the presence and absence of Bcl-x(L). Several mutants were identified that have a defect in growth when switched from a fermentable to a nonfermentable carbon source that is corrected by the expression of Bcl-x(L). These genes include the mitochondrial chaperonin TCM62, as well as previously uncharacterized genes. One of these uncharacterized genes, SVF1, promotes cell survival in mammalian cells in response to multiple apoptotic stimuli. The finding that TCM62 and the analogous human prohibitin gene also inhibit mammalian cell death following growth factor withdrawal implicates mitochondrial chaperones as regulators of apoptosis. Further characterization of the genes identified in this screen may enhance our understanding of Bcl-x(L) function in mammalian cells, and of cell survival pathways in general. 相似文献