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91.
Biotechnological conversion of agro-industrial wastewaters into biodegradable plastic, poly beta-hydroxybutyrate 总被引:1,自引:0,他引:1
Khardenavis AA Suresh Kumar M Mudliar SN Chakrabarti T 《Bioresource technology》2007,98(18):3579-3584
Waste activated sludge generated from a combined dairy and food processing industry wastewater treatment plant was evaluated for its potential to produce biodegradable plastic, poly beta-hydroxybutyric acid (PHB). Deproteinized jowar grain-based distillery spentwash yielded 42.3% PHB production (w/w), followed by filtered rice grain-based distillery spentwash (40% PHB) when used as substrates. Addition of di-ammonium hydrogen phosphate (DAHP) resulted in an increase in PHB production to 67% when raw rice grain-based spentwash was used. Same wastewater, after removal of suspended solids by filtration and with DAHP supplementation resulted in lower PHB production (57.9%). However, supplementing other wastes with DAHP led to a substantial decrease in PHB content in comparison to what was observed in the absence of DAHP. 相似文献
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Gadd45alpha is shown to be induced by a wide spectrum of DNA-damaging agents and implicated in negative regulation of cell growth by causing G2-M arrest or induction of apoptosis. In the present study, we explored the involvement of p53 in the promoter activation of Gadd45alpha as well as the role of Gadd45alpha in carboplatin (Carb) or 5-fluorouracil (5-FU)-induced apoptosis in human papillomavirus virus (HPV)-positive HEp-2 and HeLa cells. We report that Carb or 5-FU upregulate Gadd45alpha and p53 in both these cells. Transient transfection of chloramphenicol acetyl transferase (CAT)-reporter construct driven by Gadd45alpha promoter clearly indicated that Gadd45alpha upregulation was mediated through activation of its promoter. Inhibition of p53 function by dominant-negative-p53 expression partially suppressed the activation of Gadd45alpha promoter. Further, the induction of apoptosis was assessed by detection of poly (ADP-ribose) polymerase (PARP) cleavage by Western blot analysis. Inhibition of upregulated Gadd45alpha expression by antisense expression vector did not modulate the Carb or 5-FU-induced apoptosis. Overall, we conclude that Gadd45alpha promoter activation partially depends on p53 function in HPV-positive cells. Moreover, Gadd45alpha protein does not modulate Carb or 5-FU-induced apoptosis in these cells. 相似文献
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Expression of TGFβ superfamily components and other markers of oocyte quality in oocytes selected by brilliant cresyl blue staining: Relevance to early embryonic development 下载免费PDF全文
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Probing the different chaperone activities of the bacterial HSP70-HSP40 system using a thermolabile luciferase substrate 总被引:1,自引:0,他引:1
During mild heat-stress, a native thermolabile polypeptide may partially unfold and transiently expose water-avoiding hydrophobic segments that readily tend to associate into a stable misfolded species, rich in intra-molecular non-native beta-sheet structures. When the concentration of the heat-unfolded intermediates is elevated, the exposed hydrophobic segments tend to associate with other molecules into large stable insoluble complexes, also called "aggregates." In mammalian cells, stress- and mutation-induced protein misfolding and aggregation may cause degenerative diseases and aging. Young cells, however, effectively counteract toxic protein misfolding with a potent network of molecular chaperones that bind hydrophobic surfaces and actively unfold otherwise stable misfolded and aggregated polypeptides. Here, we followed the behavior of a purified, initially mostly native thermolabile luciferase mutant, in the presence or absence of the Escherichia coli DnaK-DnaJ-GrpE chaperones and/or of ATP, at 22 °C or under mild heat-stress. We concomitantly measured luciferase enzymatic activity, Thioflavin-T fluorescence, and light-scattering to assess the effects of temperature and chaperones on the formation, respectively, of native, unfolded, misfolded, and/or of aggregated species. During mild heat-denaturation, DnaK-DnaJ-GrpE+ATP best maintained, although transiently, high luciferase activity and best prevented heat-induced misfolding and aggregation. In contrast, the ATP-less DnaK and DnaJ did not maintain optimal luciferase activity and were less effective at preventing luciferase misfolding and aggregation. We present a model accounting for the experimental data, where native, unfolded, misfolded, and aggregated species spontaneously inter-convert, and in which DnaK-DnaJ-GrpE+ATP specifically convert stable misfolded species into unstable unfolded intermediates. 相似文献
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