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排序方式: 共有160条查询结果,搜索用时 31 毫秒
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Mustafa Numan Bucak Nazan Keskin Mehmet Taşpınar Kenan Çoyan Nuri Başpınar Mihai C. Cenariu Ali Bilgili Caner Öztürk Ahmet Nuri Kurşunlu 《Cryobiology》2013
The aim of this study was to determine the effects of raffinose and hypotaurine on sperm parameters after the freeze–thawing of Merino ram sperm. Totally 40 ejaculates of five Merino ram were used in the study. Semen samples, which were diluted with a Tris-based extender containing 10 mM raffinose, 5 mM hypotaurine, 5 mM raffinose +2.5 mM hypotaurine (H + R) and no antioxidant (control), were cooled to 5 °C and frozen in 0.25 ml French straws and stored in liquid nitrogen. Frozen straws were then thawed individually at 37 °C for 25 s in a water bath for evaluation. 相似文献
3.
Kenan Gumustekin Mehmet Ciftci Abdulkadir Coban Sayit Altikat Omer Aktas Mustafa Gul 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):497-502
Effects of nicotine, and nicotine + vitamin E on glucose 6-phosphate dehydrogenase (G-6PD) activity in rat muscle, heart, lungs, testicle, kidney, stomach, brain and liver were investigated in vivo and in vitro on partially purified homogenates. Supplementation period was 3 weeks (n = 8 rats per group): nicotine [0.5 mg/kg/day, intraperitoneal (ip)]; nicotine + vitamin E [75 mg/kg/day, intragastric (ig)]; and control group (receiving only vehicle). The results showed that nicotine (0.5 mg/kg, ip) inhibited G-6PD activity in the lungs, testicle, kidney, stomach and brain by 12.5% (p < 0.001), 48% (p < 0.001), 20.8% (p < 0.001), 13% (p < 0.001) and 23.35% (p < 0.001) respectively, and nicotine had no effects on the muscle, heart and liver G6PD activity. Also, nicotine + vitamin E inhibited G-6PD activity in the testicle, brain, and liver by 32.5% (p < 0.001), 21.5% (p < 0.001), and 16.5% (p < 0.001) respectively, and nicotine + vitamin E activated the muscle, and stomach G-6PD activity by 36% (p < 0.05), and 20% (p < 0.001) respectively. In addition, nicotine + vitamin E did not have any effects on the heart, lungs, and kidney G-6PD activity. In addition, in vitro studies were also carried out to elucidate the effects of nicotine and vitamin E on G-6PD activity, which correlated well with in vivo experimental results in lungs, testicles, kidney, stomach, brain and liver tissues. These results show that vitamin E administration generally restores the inactivation of G-6PD activity due to nicotine administration in various rat tissues in vivo, and also in vitro. 相似文献
4.
Alterations in DNA methylation and genome structure in two rice mutant lines induced by high pressure 总被引:2,自引:0,他引:2
Sile Shen Zhenwei Wang Xiaohui Shan Hua Wang Ling Li Xuyun Lin Likun Long Kenan Weng Bao Liu Guangtian Zou 《中国科学:生命科学英文版》2006,49(2):97-104
Pressure is expected to be an important parameter to affect characteristics of matters and control rate and equilibrium of chemical reactions. As a fundamental thermodynamic variable, it also has effects on bio-macromolecules and a lot of physiological an… 相似文献
5.
Kenan Gedik 《人类与生态风险评估》2018,24(3):754-766
The adverse effect of seafood consumption on human health is related to the bioaccessibility in contrast with the total heavy metal level in the tissues. In this study, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) edible soft tissues collected along the southern Black Sea coast were investigated using in vitro digestion model. Total Pb concentration in the tissues was found to be higher than the maximum permissible limits set by European Commission. The bioaccessibility of metals in the tissues was found to be decreased in the order: Ni (83.11%) > Cu (80.47%) > Zn (76.86%) > Cd (73.32%) > Mn (69.11%) > Pb (61.07%) > Cr (58.44%). While significant positive linear regression was observed between total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regression was found for Cd (p < .05). The hazard quotients (HQ) calculated using bioaccessible amount were detected lower than the limit (HQ <1), which may not pose a potential hazard to humans reported by US Environmental Protection Agency. In sum, mussel consumption from sampling sites may cause a potential risk concerning human health especially for Cd and Pb in case of increased portion sizes. 相似文献
6.
Fibrous poly(styrene-d-glycidylmethacrylate) (P(S-GMA)) brushes were grafted on poly(styrene-divinylbenzene) (P(S-DVB)) beads using surface initiated-atom transfer radical polymerization (SI-ATRP). Tetraethyldiethylenetriamine (TEDETA) ligand was incorporated on P(GMA) block. The multi-modal ligand attached beads were used for reversible immobilization of catalase. The influences of pH, ionic strength and initial catalase concentration on the immobilization capacities of the P(S-DVB)-g-P(S-GMA)-TEDETA beads have been investigated. Catalase adsorption capacity of P(S-DVB-g-P(S-GMA)-TEDETA beads was found to be 40.8 ± 1.7 mg/g beads at pH 6.5 (with an initial catalase concentration 1.0 mg/mL). The Km value for immobilized catalase on the P(S-DVB-g-P(S-GMA)-TEDETA beads (0.43 ± 0.02 mM) was found about 1.7-fold higher than that of free enzyme (0.25 ± 0.03 mM). Optimum operational temperature and pH was increased upon immobilization. The same support was repeatedly used five times for immobilization of catalase after regeneration without significant loss in adsorption capacity or enzyme activity. 相似文献
7.
Best T Li D Skol AD Kirchhoff T Jackson SA Yasui Y Bhatia S Strong LC Domchek SM Nathanson KL Olopade OI Huang RS Mack TM Conti DV Offit K Cozen W Robison LL Onel K 《Nature medicine》2011,17(8):941-943
Survivors of pediatric Hodgkin's lymphoma are at risk for radiation therapy-induced second malignant neoplasms (SMNs). We identified two variants at chromosome 6q21 associated with SMNs in survivors of Hodgkin's lymphoma treated with radiation therapy as children but not as adults. The variants comprise a risk locus associated with decreased basal expression of PRDM1 (encoding PR domain containing 1, with ZNF domain) and impaired induction of the PRDM1 protein after radiation exposure. These data suggest a new gene-exposure interaction that may implicate PRDM1 in the etiology of radiation therapy-induced SMNs. 相似文献
8.
Increased Oxidant Stress and Decreased Antioxidant Status in Erythrocytes of Rats Fed with Zinc-deficient Diet 总被引:2,自引:0,他引:2
Taysi S Cikman O Kaya A Demircan B Gumustekin K Yilmaz A Boyuk A Keles M Akyuz M Turkeli M 《Biological trace element research》2008,123(1-3):161-167
The aim of this study was to evaluate the lipid peroxidation, nitric oxide (NO), and free radical scavenging enzyme activities in erythrocytes of zinc (Zn)-deficient rats and to investigate the relationship among these parameters in either group. Sixteen male rats with a weight of 40-50 g were used for the experiment. The rats were divided into control (n = 8) and Zn-deficient groups. At the end of the experiment, the animals were anesthetized with ketamine-HCl (Ketalar, 20 mg/kg(-1), i.p.), and the blood was collected by cardiac puncture after thoracotomy. Blood samples were collected in vacutainer tubes without and with K(3)-EDTA as anticoagulant. Erythrocyte catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GRD), glutathione-S-transferase (GST), superoxide dismutase (SOD) activities, total (enzymatic plus nonenzymatic) superoxide scavenger activity (TSSA), nonenzymatic superoxide scavenger activity (NSSA), antioxidant potential (AOP), and serum zinc (Zn) values in the Zn-deficient group were significantly lower than those of the control group, whereas NO and malondialdehyde (MDA) levels were significantly higher than those of the control group. The results show that Zn deficiency causes a decrease in antioxidant defense system and an increase in oxidative stress in erythrocyte of rats. 相似文献
9.
The lambda Gam protein inhibits RecBCD binding to dsDNA ends 总被引:1,自引:0,他引:1
Murphy KC 《Journal of molecular biology》2007,371(1):19-24
Inactivation of the Escherichia coli RecBCD enzyme by the lambda Gam protein is an essential step that accompanies the lambda Red proteins for gene replacement using recombineering technology. It has been shown that Gam inhibits all the activities of RecBCD to the same extent. Nonetheless, some in vivo properties of recBCD mutants cannot be mimicked effectively by the expression of gam in vivo. An examination of the mechanism of Gam's inhibition of RecBCD was performed, and it was found that Gam inhibits the binding of RecBCD to double-stranded DNA ends, even if RecBCD is bound to DNA before its interaction with Gam. When ATP is added to the reaction to induce helicase activity, most of the reaction is inhibited by Gam, but residual amounts of unwinding are detected, despite a 40-fold excess of Gam/RecBCD. The same inhibitory effect of Gam was seen on RecBCD that had been modified by the P22 anti-RecBCD protein Abc2, though the inhibitory effect was diminished due to the tighter binding of Abc2-modified RecBCD to double-stranded DNA ends. These data suggest that cells containing Gam-expressing plasmids retain a small amount of uninhibited enzyme. Given the suspected instability of Gam in vivo, care must be taken when interpreting results from experiments containing Gam-inhibited RecBCD species. A revised model is proposed for Gam-induced radioresistance of E. coli to ionizing radiation. 相似文献
10.
Leard JS Cirillo MA Katsnelson E Kimiatek DA Miller TW Trebincevic K Garbalosa JC 《Journal of strength and conditioning research / National Strength & Conditioning Association》2007,21(4):1296-1299
Vertical jump height is frequently used by coaches, health care professionals, and strength and conditioning professionals to objectively measure function. The purpose of this study is to determine the concurrent validity of the jump and reach method (Vertec) and the contact mat method (Just Jump) in assessing vertical jump height when compared with the criterion reference 3-camera motion analysis system. Thirty-nine college students, 25 females and 14 males between the ages of 18 and 25 (mean age 20.65 years), were instructed to perform the countermovement jump. Reflective markers were placed at the base of the individual's sacrum for the 3-camera motion analysis system to measure vertical jump height. The subject was then instructed to stand on the Just Jump mat beneath the Vertec and perform the jump. Measurements were recorded from each of the 3 systems simultaneously for each jump. The Pearson r statistic between the video and the jump and reach (Vertec) was 0.906. The Pearson r between the video and contact mat (Just Jump) was 0.967. Both correlations were significant at the 0.01 level. Analysis of variance showed a significant difference among the 3 means F(2,235) = 5.51, p < 0.05. The post hoc analysis showed a significant difference between the criterion reference (M = 0.4369 m) and the Vertec (M = 0.3937 m, p = 0.005) but not between the criterion reference and the Just Jump system (M = 0.4420 m, p = 0.972). The Just Jump method of measuring vertical jump height is a valid measure when compared with the 3-camera system. The Vertec was found to have a high correlation with the criterion reference, but the mean differed significantly. This study indicates that a higher degree of confidence is warranted when comparing Just Jump results with a 3-camera system study. 相似文献