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261.
Mutations in the p53 tumor-suppressor gene promote increased genomic instability and cancer. Mutations in the WRN gene, encoding a DNA helicase, underlie the segmental progeroid Werner syndrome (WS). WS is also associated with increased genomic instability and elevated cancer risk. The p53 and WRN proteins can engage in direct protein-protein interactions. We report that excess WRN elicits increased cellular p53 levels and potentiates p53-mediated apoptosis. Importantly, cells derived from WS patients exhibit an attenuated and delayed induction of p53 by UV or by the topoisomerase I inhibitor camptothecin. These results suggest that WRN may participate in the activation of p53 in response to certain types of DNA damage. Furthermore, the failure to induce p53 effectively may contribute to enhanced genomic instability and elevated cancer risk in WS patients. 相似文献
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Aharon Oren 《FEMS microbiology letters》1990,73(1):41-47
Abstract Bile salts (deoxycholate, taurocholate) were used to estimate the contribution of bacteria of the Halobacterium group to bacterial community size and activity at different salinities as found in a multi-pond saltern. Low concentrations of bile salts cause lysis of halophilic archaebacteria of the Halobacterium group, while halophilic eubacteria and halococci remain microscopically intact. Upon addition of bile salts, total bacterial numbers (as estimated microscopically) in saltern ponds at salinities below 250 g/l did not decrease, while above this salinity bacterial numbers decreased by 30–50%. To estimate the contribution of halobacteria to overall heterotrophic activity, the effect of bile salt addition was tested on the incorporation of labelled amino acids. In saltern ponds of a salinity below 250 g/l activity was not greatly inhibited by taurocholate, while at salinity above 300 g/l taurocholate completely abolished incorporation of amino acids. 相似文献
264.
Factors determining the development of algal and bacterial blooms in the Dead Sea: a study of simulation experiments in outdoor ponds 总被引:2,自引:0,他引:2
Abstract To simulate the occurrence of bacterial and algal blooms in the Dead Sea, we filled 5.6 m3 outdoor ponds with mixtures of Dead Sea water and Mediterranean water, at different seasons, and studied the effect of salinity and of addition of glycerol, glucose and different concentrations of phosphate on the rate and extent of bacterial and algal growth. Addition of phosphate appeared to be essential for the development of mass blooms of both the green alga Dunaliella and of the red halobacteria. In the presence of phosphate the growth rates were high only when the Dead Sea water was diluted by at least 25–35% with Mediterranean water. Also, at low temperatures (14–17°C) mass blooms of bacteria and algae occurred, but growth rates were reduced, and the maximal salinity at which growth was observed shifted to a lower value. Glucose, glycerol and a Dunaliella bloom all proved to be suitable carbon sources for mass development of halobacteria. 相似文献
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Smoothened is a member of the G-protein coupled receptor (GPCR) family responsible for the transduction of the Hedgehog signal to the intracellular effectors of the Hedgehog signaling pathway. Aberrant regulation of this receptor is implicated in many cancers but also in neurodegenerative disorders. Despite the pharmacological relevance of this receptor, very little is known about its functional mechanism and its physiological ligand. In order to characterize this receptor for basic and pharmacological interests, we developed the expression of human Smoothened in the yeast Saccharomyces cerevisiae and Smoothened was then purified. Using Surface Plasmon Resonance technology, we showed that human Smoothened was in a native conformational state and able to interact with its antagonist, the cyclopamine, both at the yeast plasma membrane and after purification. Thermostability assays on purified human Smoothened showed that this GPCR is relatively stable in the classical detergent dodecyl-β-d-maltoside (DDM). The fluorinated surfactant C8F17TAC, which has been proposed to be less aggressive towards membrane proteins than classical detergents, increased Smoothened thermostability in solution. Moreover, the replacement of a glycine by an arginine in the third intracellular loop of Smoothened coupled to the use of the fluorinated surfactant C8F17TAC during the mutant purification increased Smoothened thermostability even more. These data will be very useful for future crystallization assays and structural characterization of the human receptor Smoothened. 相似文献
267.
Aharon Oren 《FEMS microbiology letters》1990,73(3):187-192
Abstract Antibiotics affecting protein synthesis were used to differentiate between the activity of different groups of organisms (halophilic archaebacteria, eubacteria and eukaryotes) in water samples from hypersaline ecosystems. Anisomycin (inhibiting both archaebacterial halophiles and eukaryotes) can be used to quantitate the contribution of the archaebacterial halophiles to amino acid incorporation by the microbial community, when cycloheximide (inhibiting eukaryotic protein synthesis, but not affecting halobacteria) is used as a control. Both in saltern ponds at salinities above 300 g/1 and in Dead Sea surface water more than 95% of the amino acid incorporation activity was abolished by anisomycin, but not by cycloheximide. Inhibition by anisomycin was well correlated with inhibition by low concentrations of bile salts, which specifically affect bacteria of the Halobacterium group. Chloramphenicol (an inhibitor of eubacterial protein synthesis) quantitatively inhibited amino acid incorporation in saltern brines of relatively low salinity, but also caused significant (28–42%) inhibition at high salinities. Erythromycin was also found valuable in the estimation of activities of the different bacterial groups. 相似文献
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Cumoniscus kruppi Bonnier, the only tantulocarid known from a cumacean host, is redescribed from a tantulus larva collected from the Bay of Biscay. The host is a male leuconid cumacean. This genus is placed in the family Deoterthridae, and can be distinguished from other genera by the pore pattern on the cephalic shield, the reduced setae on the sixth legs and the presence of tiny curved spinules on the endopod of thoracopods 2 to 5. 相似文献
270.
Victoria R. Rendell Robert H. Gilman Edward Valencia Gerson Galdos-Cardenas Manuela Verastegui Leny Sanchez Janet Acosta Gerardo Sanchez Lisbeth Ferrufino Carlos LaFuente Maria del Carmen Abastoflor Rony Colanzi Caryn Bern 《PloS one》2015,10(3)