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91.
92.
Mammalian oocytes mature in follicular fluid (FF), surrounded by follicular cells. In the present study, in vitro maturation of bovine oocytes cultured in FF from dominant follicles 15-17mm in diameter (with various forms of heat pretreatment) and supplementation with follicular wall from follicles 3-5mm in diameter (FW1) were examined. Heat pretreatment of FF was as follows: (1) no treatment (FF1); (2) 56 degrees C for 30min (FF2); and (3) 100 degrees C for 20s (FF3). After IVM in FF1, oocytes underwent IVF and IVC and embryo development was assessed (up to the morula stage). The rate of oocyte maturation was decreased in pure FF1 versus control (44.5% versus 62.8%, P<0.001). In the control medium, FW1 did not significantly affect nuclear maturation. By contrast, the addition of FW1 to FF1 increased the rate of matured oocytes approximately two-fold (85.9% versus 45.6%, P<0.001). Furthermore, the maturation rate in the FF+FW1 system declined (from 85.9 to 71.0%, P<0.001), whereas that in the FF system increased (from 45.6 to 71.6%, P<0.001) with increased temperature of the FF treatment. Supplementation of the control medium with FW1 increased the yield of morulae (42.6% versus 13.7%, P<0.001). However, the stimulatory effect of FW1 on the morula rate was much higher in pure FF1 (72.5% versus 31.7%, P<0.001). These findings indicated, for the first time, the stimulatory impact of FW1 on in vitro maturation and early developmental capacity of bovine oocytes cultured in pure FF from dominant follicles. We also inferred that bovine FF constituents affecting bovine oocyte maturation and the meiosis-promoting ability of the FW were heat-labile. 相似文献
93.
Lyon CM Klinge DM Liechty KC Gentry FD March TH Kang T Gilliland FD Adamova G Rusinova G Telnov V Belinsky SA 《Radiation research》2007,168(4):409-414
Epigenetic inactivation of genes by promoter hypermethylation, a major mechanism in the initiation and progression of tobacco-induced cancer, has also been associated with lung cancer induced through environmental and occupational exposures. Our previous study of gene methylation in workers from the MAYAK nuclear enterprise identified a significantly higher prevalence for methylation of the p16 gene (CDKN2A) in adenocarcinomas from workers compared to tumors from non-worker controls. The purpose of this investigation was to determine whether genes in addition to p16 are "targeted" for silencing and whether overall gene methylation was more common in radiation-induced adenocarcinoma. A significant increase in the prevalence of methylation of GATA5 was seen in tumors from workers compared to tumors from controls. The prevalence for methylation of PAX5 beta and H-cadherin did not differ in tumors from workers and controls. Evaluating the frequency for methylation of a five-gene panel revealed that 93% of adenocarcinomas from workers compared to 66% of tumors from controls were methylated for at least one gene. Moreover, a twofold increase was seen in the number of tumors methylated for three or more genes for tumors from workers compared to controls. Increased frequency for inactivation of genes by promoter hypermethylation and targeting of tumor suppressor genes such as GATA5 may be factors that contribute to the increased risk for lung cancer associated with radiation exposure. 相似文献
94.
Kaznacheyeva E Glushankova L Bugaj V Zimina O Skopin A Alexeenko V Tsiokas L Bezprozvanny I Mozhayeva GN 《The Journal of biological chemistry》2007,282(32):23655-23662
In most non-excitable cells, calcium (Ca(2+)) release from the inositol 1,4,5-trisphosphate (InsP(3))-sensitive intracellular Ca(2+) stores is coupled to Ca(2+) influx through the plasma membrane Ca(2+) channels whose molecular composition is poorly understood. Several members of mammalian TRP-related protein family have been implicated to both receptor- and store-operated Ca(2+) influx. Here we investigated the role of the native transient receptor potential 3 (TRPC3) homologue in mediating the store- and receptor-operated calcium entry in A431 cells. We show that suppression of TRPC3 protein levels by small interfering RNA (siRNA) leads to a significant reduction in store-operated calcium influx without affecting the receptor-operated calcium influx. With single-channel analysis, we further demonstrate that reduction of TRPC3 levels results in suppression of specific subtype of store-operated calcium channels and activation of store-independent channels. Our data suggest that TRPC3 is required for the formation of functional store-operated channels in A431 cells. 相似文献
95.
Zawacka-Pankau J Issaeva N Hossain S Pramanik A Selivanova G Podhajska AJ 《The Journal of biological chemistry》2007,282(4):2466-2472
Photodynamic therapy (PDT) of cancer is an alternative treatment for tumors resistant to chemo- and radiotherapy. It induces cancer cell death mainly through generation of reactive oxygen species by a laser light-activated photosensitizer. It has been suggested that the p53 tumor suppressor protein sensitizes some human cancer cells to PDT. However, there is still no direct evidence for this. We have demonstrated here for the first time that the photosensitizer protoporphyrin IX (PpIX) binds to p53 and disrupts the interaction between p53 tumor suppressor protein and its negative regulator HDM2 in vitro and in cells. Moreover, HCT116 colon cancer cells exhibited a p53-dependent sensitivity to PpIX in a dose-dependent manner, as was demonstrated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and fluorescence-activated cell sorter (FACS) analysis of cell cycle profiles. We have also observed induction of p53 target pro-apoptotic genes, e.g. puma (p53-up-regulated modulator of apoptosis), and bak in PpIX-treated cells. In addition, p53-independent growth suppression by PpIX was detected in p53-negative cells. PDT treatment (2 J/cm2) of HCT116 cells induced p53-dependent activation of pro-apoptotic gene expression followed by growth suppression and induction of apoptosis. 相似文献
96.
97.
Fadeeva MS Yakovtseva EA Belevich GA Bertsova YV Bogachev AV 《Archives of microbiology》2007,188(4):341-348
The expression of genes encoding sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) was studied in the marine bacterium Vibrio harveyi and in the enterobacterium Klebsiella pneumoniae. It has been shown that such parameters as NaCl concentration, pH value, and presence of an uncoupler in the growth media
do not influence significantly the level of nqr expression. However, nqr expression depends on the growth substrates used by these bacteria. Na+-NQR is highly repressed in V. harveyi during anaerobic growth, and nqr expression is modulated by electron acceptors and values of their redox potentials. The latter effect was shown to be independent
of the ArcAB regulatory system.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Accession
number: EF394942 (Vibrio harveyi
arcB gene, partial cds). 相似文献
98.
Ploquin M Petukhova GV Morneau D Déry U Bransi A Stasiak A Camerini-Otero RD Masson JY 《Nucleic acids research》2007,35(8):2719-2733
Genetic analysis of fission yeast suggests a role for the spHop2–Mnd1 proteins in the Rad51 and Dmc1-dependent meiotic recombination pathways. In order to gain biochemical insights into this process, we purified Schizosaccharomyces pombe Hop2-Mnd1 to homogeneity. spHop2 and spMnd1 interact by co-immunoprecipitation and two-hybrid analysis. Electron microscopy reveals that S. pombe Hop2–Mnd1 binds single-strand DNA ends of 3′-tailed DNA. Interestingly, spHop2-Mnd1 promotes the renaturation of complementary single-strand DNA and catalyses strand exchange reactions with short oligonucleotides. Importantly, we show that spHop2-Mnd1 stimulates spDmc1-dependent strand exchange and strand invasion. Ca2+ alleviate the requirement for the order of addition of the proteins on DNA. We also demonstrate that while spHop2-Mnd1 affects spDmc1 specifically, mHop2 or mHop2-Mnd1 stimulates both the hRad51 and hDmc1 recombinases in strand exchange assays. Thus, our results suggest a crucial role for S. pombe and mouse Hop2-Mnd1 in homologous pairing and strand exchange and reveal evolutionary divergence in their specificity for the Dmc1 and Rad51 recombinases. 相似文献
99.
Extended exposure of Escherichia coli to temperatures above and below their growth optimum led to significant changes in oxidant production and antioxidant defense. At 20 °C an increase in the intracellular H2O2 concentration and oxidized glutathione (GSSG) level was observed against a background of low levels of reduced glutathione (GSH) and decreased catalase and glutathione reductase (GOR) activities. The intracellular H2O2 and GSSG concentrations had minimal values at 30 and 37 °C, but rose again at 42 °C, suggesting that oxidative processes were intensified at high temperatures. An increase in temperature from 20 to 42 °C led to an elevation in the oxygen respiration rate and superoxide production; a 5-fold increase in the intracellular GSH concentration and in the GSH:GSSG ratio occurred simultaneously. Catalase HPI and GOR activities were elevated 4.4- and 1.5-fold, respectively. Prolonged exposure to sublethal temperatures facilitated an adaptation to subsequent oxidative stress produced by the addition of H2O2. 相似文献
100.
Alhamadsheh MM Waters NC Huddler DP Kreishman-Deitrick M Florova G Reynolds KA 《Bioorganic & medicinal chemistry letters》2007,17(4):879-883
A series of cyclic sulfones has been synthesized and their activity against beta-ketoacyl-ACP-synthase III (FabH) has been investigated. The compounds are selectively active against Escherichia coli FabH (ecFabH), but not Mycobacterium tuberculosis FabH (mtFabH) or Plasmodium falciparum KASIII (PfKASIII). The activity against ecFabH ranges from 0.9 to >100microM and follows a consistent general SAR trend. Many of the compounds were shown to have antimalarial activity against chloroquine (CQ)-sensitive (D6) P. falciparum (IC(50)=5.3microM for the most potent inhibitor) and some were active against E. coli (MIC=6.6microg/ml for the most potent inhibitor). 相似文献