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171.
Yongmei Guo Sumei Yan Jian Gong Lu Jin Binlin Shi 《Biological trace element research》2018,184(1):75-82
To elucidate the effect of selenium (Se) on antioxidant function of mammary glands in dairy cows and the underlying mechanism, an experiment was conducted using a single-factor completely randomized design study. Bovine mammary epithelial cells (BMECs) were randomly divided into four groups: control, Se treatment, 2,4-dinitrochlorobenzene (DNCB) inhibition, and Se prevention. Treatment of BMECs with Se was found to significantly reverse decreased cell proliferation and the expression of thioredoxin reductase (TrxR) after DNCB exposure. DNCB-induced activation of apoptosis signaling kinase-1 (ASK-1), which activates the mitogen-activated protein kinase (MAPK) pathway, was reduced in BMECs treated with Se. Additionally, our results indicated that Se treatment resulted in lower intracellular accumulation of arachidonic acid (ARA) and 15-hydroperoxyeicosatetraenoic acid (15-HPETE) due to suppressed expression of cytosolic phospholipase A2 (cPLA2) regulated by p38MAPK and c-Jun N-terminal kinase (JNK) in DNCB-stimulated BMECs. Taken together, these findings suggest that Se treatment improved the antioxidant function of dairy cow mammary glands and protected cells from oxidative damage primarily by increasing the activity of TrxR, inhibiting the activation of the MAPK signaling pathway, and thus decreasing the content of ARA and its related metabolites. 相似文献
172.
以黄瓜品种‘津春2号’为材料,在育苗基质中添加亚精胺(Spd)和丛枝菌根真菌(AMF),研究外源Spd和AMF对黄瓜幼苗生长、光合作用、果实产量和品质以及根际微生物和酶活性的影响.结果表明:育苗基质中同时添加Spd和AMF,可促进黄瓜幼苗生长,提高根系活力和果实产量,改善品质,并促进养分吸收;Spd和AMF提高黄瓜幼苗净光合速率、实际光化学效率、表观量子效率、羧化效率和光呼吸速率,增加基质中细菌和放线菌数量,而降低真菌数量,并提高蔗糖酶、中性磷酸酶、过氧化氢酶和脲酶的活性.说明育苗基质中同时添加Spd和AMF,可提高黄瓜植株光能利用效率,促使黄瓜幼苗根际微生物区系从低肥力的"真菌型"向高肥力的"细菌型"转化,加速有机磷和有机态氮的分解与转化,为黄瓜生长发育提供比较充足的N、P等养分,从而促进黄瓜植株生长,提高产量并改善品质.Spd可提高AMF侵染率,两者对黄瓜幼苗生长具有明显的叠加效应,说明在接种AMF的基质中添加Spd,是一种可增强AMF侵染率的有效方法. 相似文献
173.
冷冻干燥对重组酵母乙型肝炎疫苗效力(抗原性)的影响 总被引:5,自引:0,他引:5
重组酵母乙型肝炎疫苗(酵母乙肝疫苗)加入保护剂后冷冻干燥,观察是否影响疫苗抗原性和稳定性。按5%和1%的比例,在酵母乙肝疫苗原液中分别加入蔗糖和明胶,低温冷冻干燥,制备3批冻干疫苗,分别进行体外相对效力和小鼠ED50测定。加保护剂冻干后酵母乙肝疫苗体外相对效力和小鼠ED50值较冻干前改变不大,而4℃放置和热加速后的稳定性均优于液体疫苗。因此现有酵母乙肝疫苗加入保护剂冻干后,显著提高了疫苗的稳定性,为进一步制备稳定的疫苗参考品打下了初步基础。 相似文献
174.
Conventional kinesin KIF5B mediates insulin-stimulated GLUT4 movements on microtubules 总被引:15,自引:0,他引:15
Semiz S Park JG Nicoloro SM Furcinitti P Zhang C Chawla A Leszyk J Czech MP 《The EMBO journal》2003,22(10):2387-2399
Insulin stimulates glucose uptake in muscle and adipose cells by mobilizing intracellular membrane vesicles containing GLUT4 glucose transporter proteins to the plasma membrane. Here we show in live cultured adipocytes that intracellular membranes containing GLUT4-yellow fluorescent protein (YFP) move along tubulin-cyan fluorescent protein-labeled microtubules in response to insulin by a mechanism that is insensitive to the phosphatidylinositol 3 (PI3)-kinase inhibitor wortmannin. Insulin increased by several fold the observed frequencies, but not velocities, of long-range movements of GLUT4-YFP on microtubules, both away from and towards the perinuclear region. Genomics screens show conventional kinesin KIF5B is highly expressed in adipocytes and this kinesin is partially co-localized with perinuclear GLUT4. Dominant-negative mutants of conventional kinesin light chain blocked outward GLUT4 vesicle movements and translocation of exofacial Myc-tagged GLUT4-green fluorescent protein to the plasma membrane in response to insulin. These data reveal that insulin signaling targets the engagement or initiates the movement of GLUT4-containing membranes on microtubules via conventional kinesin through a PI3-kinase-independent mechanism. This insulin signaling pathway regulating KIF5B function appears to be required for GLUT4 translocation to the plasma membrane. 相似文献
175.
HaploBlockFinder: haplotype block analyses 总被引:8,自引:0,他引:8
Recent studies have unveiled discrete block-like structures of linkage disequilibrium (LD) in the human genome. We have developed a set of computer programs to analyze the block-like LD structures (haplotype blocks) based on haplotype data. Three definitions of haplotype block are supported, including minimal LD range, no historic recombination, and chromosome coverage. Tagged SNPs that uniquely distinguish common haplotypes are identified. A greedy algorithm was used to improve the efficiency. Two separate utilities were also provided to assist visual inspection of haplotype block structure and pattern of linkage disequilibrium. AVAILABILITY: A web interface for the HaploBlockFinder is available at http://cgi.uc.edu/cgi-bin/kzhang/haploBlockFinder.cgi the source codes are also freely available on the web site. 相似文献
176.
Lee SC Kim JH Park ES Kim DK Kim YG Yun HY Kwon NS Im MJ Baek KJ 《Molecules and cells》2003,16(3):285-290
Galphah (transglutaminase type II; tissue transglutaminase) is a bifunctional enzyme with transglutaminase (TGase) and guanosine triphosphatase (GTPase) activities. The GTPase function of Galphah is involved in hormonal signaling and cell growth while the TGase function plays an important role in apoptosis and in cross-linking extracellular and intracellular proteins. To analyze the regulation of these dual enzymatic activities we examined their calcium-dependence and thermal stability in enzymes from several cardiac sources (mouse heart, and normal, ischemic and dilated cardiomyopathic human hearts). The GTP binding activity of Galphah was markedly inhibited by Ca2+ whereas the TGase activity was strongly stimulated, suggesting that Ca2+ acts as a regulator, switching Galphah from a GTPase to a TGase. The TGase function of Galphah of both mouse and human hearts was more thermostable in the presence of Ca2+. 相似文献
177.
荧光假单胞菌抗噬菌体菌株的选育 总被引:4,自引:2,他引:4
本实验从荧光假单胞菌(Pseudomonasfluorescens)AS—3菌株的不正常发酵液中分离到一种噬菌体,将其命名为PFAS。AS—3菌株能利用葡萄糖发酵产生D-异维生素C的前体物质2-酮基-D-葡萄糖酸。电镜观察表明PFAS噬菌体呈蝌蚪形,具有直径为66nm的六角形头部及长117nm的尾部。通过紫外线诱变及自然选育两种途径,配合简便有效的初筛方法,经多次分离、纯化、复筛最终在摇并发酵试验中获得6株产量稳定地高于对照敏感菌的抗噬菌体菌株,可望用于生产。 相似文献
178.
179.
Ding Xiaotao Jiang Yuping Wang Hong Jin Haijun Zhang Hongmei Chen Chunhong Yu Jizhu 《Acta Physiologiae Plantarum》2013,35(5):1427-1438
The effects of 6-benzylaminopurine (6-BA) on plant growth, net photosynthetic rate, relative chlorophyll content, soluble protein, carbohydrates contents and antioxidant systems of cucumber (Cucumis sativus L.) under low-light environment were investigated using two different cucumber cultivars. The results showed that the weak light resulted in the remarkable decrease in plant net photosynthetic rate, relative chlorophyll content, soluble protein and carbohydrates contents, but promoted the superoxide dismutase and guaiacol peroxidase activities. However, application of 6-BA alleviated the reduction of the correlative parameters and mediated the changes of antioxidant systems. The potential mechanisms may involve the following aspects: 6-BA clearly enhanced the plants’ tolerance to low light by increasing chlorophyll content, reducing the production of superoxide radical (O 2 ·? ), and enhancing the quenching of hydrogen peroxide (H2O2), consequently alleviating the injury of photosynthetic system, and further increasing the efficiency of CO2 assimilation, producing more carbohydrates which can meet the growth need of cucumber. Meanwhile, the present study indicated that cucumber of Europe mini type (Chunqiuwang) was more tolerant to low light than HuaNan type (Huza No.3). 相似文献
180.
辽东栎叶片凋落物在不同气候带下的分解及其主要元素释放的比较
王立新 王 瑾 黄建辉 相似文献