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91.
The Msb3p and Msb4p proteins of Saccharomyces cerevisiae are members of the Ypt/Rab-specific GTPase-activating protein (GAP) family. They are essential to vesicular trafficking and
involved in the regulation of exocytosis and in the organization of the actin cytoskeleton, but their exact biological roles
have yet to be determined. The msb3 msb4 yeast double mutation causes growth inhibition in the presence of DMSO and/or caffeine, affects the organization of the actin
cytoskeleton, produces a random budding pattern in diploid cells, and affects segregation of the nucleus. To find cell components
that interact genetically with the products of the MSB3 and MSB4 genes, we screened a genomic library for multicopy suppressor genes restoring normal growth of the double mutant in the presence
of DMSO and caffeine. Six genes were identified, and the extent to which each gene corrects specific growth defects of the
msb3 msb4 mutant is described. The encoded suppressors were classified on the basis of functional features into four groups: vesicular
transport proteins (Sec7p, Vps35p, and Uso1p), a protein involved in cell division (Sap155p), a molecular chaperon (Ssz1p),
and a protein associated with the 25S proteasome (Cic1p). 相似文献
92.
93.
Sophie Biver Aurore Stroobants Daniel Portetelle Micheline Vandenbol 《Journal of industrial microbiology & biotechnology》2014,41(3):479-488
New β-glucosidase activities were identified by screening metagenomic libraries constructed with DNA isolated from the topsoil of a winter wheat field. Two of the corresponding proteins, displaying an unusual preference for alkaline conditions, were selected for purification by Ni-NTA chromatography. AS-Esc6, a 762-amino-acid enzyme belonging to glycoside hydrolase family 3, proved to be a mesophilic aryl-β-glucosidase with maximal activity around pH 8 and 40 °C. A similar pH optimum was found for AS-Esc10, a 475-amino-acid GH1-family enzyme, but this enzyme remained significantly active across a wider pH range and was also markedly more stable than AS-Esc6 at pH greater than 10. AS-Esc10 was found to degrade cellobiose and diverse aryl glycosides, with an optimal temperature of 60 °C and good stability up to 50 °C. Unlike AS-Esc6, which showed a classically low inhibitory constant for glucose (14 mM), AS-Esc10 showed enhanced activity in the presence of molar concentrations of glucose. AS-Esc10 was highly tolerant to hydrogen peroxide and also to sodium dodecyl sulfate, this being indicative of kinetic stability. This unique combination of properties makes AS-Esc10 a particularly promising candidate whose potential in biotechnological applications is worth exploring further. 相似文献
94.
95.
Methods were devised to standardize cardiopulmonary radiographs of infants and children. With these techniques, films can be taken either at the end of inspiration and in systole, or at the end of inspiration alone. A statistical evaluation of these two methods demonstrated their superiority over the usual procedure. The use of these techniques is strongly recommended in patients of the pediatric age group. 相似文献
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97.
Glucocorticoid (GC)-induced osteoporosis has been attributed to a GC-induced suppression of pre-osteoblast proliferation. Our previous work identified a critical role for mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) in mediating the anti-proliferative effects of GCs in immortalized pre-osteoblasts, but we subsequently found that MKP-1 null mice were not protected against the pathological effects of GCs on bone. In order to reconcile this discrepancy, we have assessed the effects of GCs on proliferation, activation of the MAPK ERK1/2 and MKP-1 expression in primary adipose-derived stromal cells (ADSCs) and ADSC-derived pre-osteoblasts (ADSC-OBs). ADSCs were isolated by means of collagenase digestion from adipose tissue biopsies harvested from adult male Wistar rats. ADSC-OBs were prepared by treating ADSCs with osteoblast differentiation media for 7 days. The effects of increasing concentrations of the GC dexamethasone on basal and mitogen-stimulated cell proliferation were quantified by tritiated thymidine incorporation. ERK1/2 activity was measured by Western blotting, while MKP-1 expression was quantified on both RNA and protein levels, using semi-quantitative real-time PCR and Western blotting, respectively. GCs were strongly anti-proliferative in both naïve ADSCs and ADSC-OBs, but had very little effect on mitogen-induced ERK1/2 activation and did not upregulate MKP-1 protein expression. These findings suggest that the anti-proliferative effects of GCs in primary ADSCs and ADSC-OBs in vitro do not require the inhibition of ERK1/2 activation by MKP-1, which is consistent with our in vivo findings in MKP-1 null mice. 相似文献
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99.
Micheline Kézia Cordeiro‐Araújo Maria do Carmo Bittencourt‐Oliveira 《Phycological Research》2013,61(1):1-6
The active release of microcystins in cyanobacterium Microcystis aeruginosa (Kützing) Kützing, strain BCCUSP232 was confirmed. The microcystin release is controlled by an endogenous rhythm, pointing to a biosynthetic pattern of toxins in cyanobacteria. Proofing tests for this active release were carried out by experiments at two independent 24 h cycles, light : dark and continuous light (12:12 h) along the exponential growing phase. Cultivation samples at light, temperature and photoperiod controlled conditions were collected in 2‐h intervals. Microcystin concentrations from the pellet aliquots (intracellular microcystin per cell‐quota –IMC) and supernatant (extracellular microcystin per equivalent cell‐quota – EMC) were quantified with enzyme linked immunosorbent assay. The IMC concentrations showed increases and decreases in both cycles. Decreases of IMC clearly demonstrate that the toxin was actively released to the surrounding medium and not by cell lysis. The total microcystins concentrations (IMC and EMC) between the light : dark and continuous light cycles presented similar variations between the same hours. 相似文献
100.
Câmara Paulo E. A. S. Eisenlohr Pedro V. Coelho Lívia C. Carvalho-Silva Micheline Amorim Eduardo T. Convey Peter Pinto Otavio H. B. Rosa Luiz Henrique 《Extremophiles : life under extreme conditions》2021,25(5-6):501-512
Extremophiles - Since the nineteenth century, a ring-forming disease attacking Antarctic mosses has been reported. However, to date, only the effects on the mosses themselves are known. In this... 相似文献