51 resultados para 2glycosidic-isoprenoid-glycerol dibiphytanyl nonitol tetraether

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Glycerol and dimethyl sulfoxide (DMSO) are widely used as penetrating cryoprotectants in the freezing of sperm, and various concentrations are applied in different species and laboratories. The present study aimed to examine the effect of these two cryoprotectants at different concentrations (2%, 5%, 10%, and 15% glycerol or DMSO) on rhesus monkey sperm cryopreservation. The results showed that the highest recovery of post-thaw sperm motility, and plasma membrane and acrosome integrity was achieved when the sperm was frozen with 5% glycerol. Spermatozoa cryopreserved with 15% DMSO showed the lowest post-thaw sperm motility, and spermatozoa cryopreserved with 15% glycerol and 15% DMSO showed the lowest plasma membrane integrity among the eight groups. The results achieved with 5% glycerol were significantly better for all parameters than those obtained with 5% DMSO. The functional cryosurvival of sperm frozen with 5% glycerol was further assessed by in vitro fertilization (IVF). Overall, 85.7% of the oocytes were successfully fertilized, and 51.4% and 5.7% of the resulting zygotes developed into morulae and blastocysts, respectively. The results indicate that the type and concentration of the penetrating cryoprotectant used can greatly affect the survival of rhesus monkey sperm after it is frozen and thawed. The suitable glycerol level for rhesus monkey sperm freezing is 5%, and DMSO is not suitable for rhesus monkey sperm cryopreservation. (C) 2004 Wiley-Liss, Inc.

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Various organometallic compounds (diphenylzinc, dibenzylzinc, dicyclohexylzinc, bis( pentafluorophenyl) zinc, diethylzinc, di(n-butyl) zinc, triethylaluminum) were used to form Y(CCl3COO)(3)-organometallic compound-glycerol catalyst for the copolymerization of carbon dioxide and propylene oxide. It was found that Y(CCl3COO)(3)-diphenylzinc-glycerol catalyst showed the highest catalytic activity, at optimum conditions the yield could be as high as 478.8 ( g polymer/mol Zn h).

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Vapor-phase dehydration of glycerol to produce acrolein was investigated at 320 A degrees C over rare earth (including La, Ce, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu) pyrophosphates, which were prepared by precipitation method. The most promising catalysts were characterized by means of XRD, FT-IR, TG-DTA, BET and NH3-TPD measurements. The excellent catalytic performance of rare earth pyrophosphate depends on the appropriate surface acidity which can be obtained by the control of pH value in the precipitation and the calcination temperature, e.g. Nd-4(P2O7)(3) precipitated at pH = 6 and calcined at 500 A degrees C in the catalyst preparation.

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The biosynthesis of glycolipids in E. fasciculatus was studied by C-14 label and chase. The fatty acids in sulphoquinovosyl diacylglycerol (SQDG) were almost 16-carbon and 18-carbon ones. In addition to the two fatty acids, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) contained 8.5 mol% and 31.0 mol% of eicosapentaenoic acid (20 : 5), respectively, and this fatty acid was usually distributed in the sn-1 position of the glycerol backbone. When plants were incubated with [2-C-14] acetate, differences existed in the positional distribution of the labeled fatty acids in sn-1 and sn-2 among the three glycerolipids. In SQDG C-14-labeled fatty acids were distributed uniformly in the sn-1 and sn-2 positions. In DGDG, C-14-labeled fatty acids were mainly distributed in the sn-2 position. In MGDG, the radioactivity of fatty acids in sn-1 position was far greater than that in sn-2 position after a 30 min pulse label, and the difference in radioactivity between the two positions decreased rapidly. The above results indicated that differences in the positional distribution of C-14-labeled fatty acids between sn-1 and sn-2 positions might be related to 20 : 5 and the biosynthesis of DGDG. Our results also suggested that E. fasciculatus had the same DGDG biosynthetic pathway as that in higher plants and galactosyl transferase was selective for MGDC.

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利用反义技术研究生物代谢途径以及对其生物合成进行调控成为植物次生代谢研究领域内一个重要手段之一,并与新兴的RNAi技术一起成为本领域内重要的研究热点。在植物类异戊二烯代谢途径中存在着羟甲基戊二酰辅酶A还原酶(HMGR)、法呢基焦磷酸合酶(FPS)和鲨烯合酶(SQS)等几种关键的分支酶,他们被认为在异戊二烯类的生物合成中发挥着关键的调节作用。其中,鲨烯合酶处于HMGR和FPS的下游,并与倍半萜合酶等利用共同的前体-法呢基二磷酸(FPP),以FPP起始合成一系列的下游产物。因此,FPP成为类异戊二烯途径中的关键调节点之一。本论文基于此目的,利用反义技术研究了FPP合成鲨烯这一途径受到抑制对其他以FPP为生物合成前体的代谢支路的影响。 利用植物双元转化载体pBI121,将青蒿中鲨烯合酶基因的cDNA(约1.5kb)序列插入到pBI121中,取代原有的GUS序列,构建成植物转化载体pBIASS。以根癌农杆菌为介导,将青蒿鲨烯合酶反义基因序列导入到烟草,整合到其基因组中 ,成功获得转基因植株。对转基因烟草进行分子检测表明,外源鲨烯合酶基因的序列已经稳定整合到烟草基因组中,并对内源的烟草鲨烯合酶基因表达产生影响。转基因烟草中检测到内源鲨烯合酶基因的mRNA的水平降低。对鲨烯合酶下游产物之一的胆固醇的含量分析显示,活性减低的鲨烯合酶使胆固醇的生物合成下降约40%左右。同时,另一条以FPP为共同前体的二萜代谢途径产物之一GA3的含量得到了提高,比对照提高约30%。

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利用反义技术研究生物代谢途径以及对其生物合成进行调控成为植物次生代谢研究领域内一个重要手段之一,并与新兴的RNAi技术一起成为本领域内重要的研究热点。在植物类异戊二烯代谢途径中存在着羟甲基戊二酰辅酶A还原酶(HMGR)、法呢基焦磷酸合酶(FPS)和鲨烯合酶(SQS)等几种关键的分支酶,他们被认为在异戊二烯类的生物合成中发挥着关键的调节作用。其中,鲨烯合酶处于HMGR和FPS的下游,并与倍半萜合酶等利用共同的前体-法呢基二磷酸(FPP),以FPP起始合成一系列的下游产物。因此,FPP成为类异戊二烯途径中的关键调节点之一。本论文基于此目的,利用反义技术研究了FPP合成鲨烯这一途径受到抑制对其他以FPP为生物合成前体的代谢支路的影响。 利用植物双元转化载体pBI121,将青蒿中鲨烯合酶基因的cDNA(约1.5kb)序列插入到pBI121中,取代原有的GUS序列,构建成植物转化载体pBIASS。以根癌农杆菌为介导,将青蒿鲨烯合酶反义基因序列导入到烟草,整合到其基因组中 ,成功获得转基因植株。对转基因烟草进行分子检测表明,外源鲨烯合酶基因的序列已经稳定整合到烟草基因组中,并对内源的烟草鲨烯合酶基因表达产生影响。转基因烟草中检测到内源鲨烯合酶基因的mRNA的水平降低。对鲨烯合酶下游产物之一的胆固醇的含量分析显示,活性减低的鲨烯合酶使胆固醇的生物合成下降约40%左右。同时,另一条以FPP为共同前体的二萜代谢途径产物之一GA3的含量得到了提高,比对照提高约30%。

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在光系统I(PSI)内部结合有大量的水分子,而这些水分子的生理功能还不清楚。在本工作中,我们通过外加具有渗透活性和吸水强的多羟基化合物甘油和蔗糖来改变PSI环境中水的含量,研究水的改变对PSI结构与功能的影响。主要结果如下: 1.甘油和蔗糖对PSI的电子传递产生影响,影响程度和大小与它们的浓度有关。一般地,低浓度的甘油和蔗糖可促进PSI的电子传递,而在高浓度时,这种促进作用有所减弱。但过高浓度的甘油(>60%, v/v)会抑制PSI的电子传递活性。 2.与对PSI电子传递的影响趋势相类似,在低浓度的甘油和蔗糖存在下,PSI的光化学反应活性(PSI反应中心色素P700的光氧化还原能力)大为增加,而较高浓度的甘油和蔗糖对P700的氧化还原能力有所抑制。 3.甘油和蔗糖也会改变PSI中的主体色素(bulk chlorophyll)和长波色素或红色素(red chlorophyll)之间的能量分布。它们的作用导致激发能分配失衡,使更多的激发能分配到红色素。 4.甘油和蔗糖的作用还会影响PSI的蛋白质构象。甘油使PSI蛋白质内部的色氨酸残基(Trpapolar)处于更加疏水的微环境,而蔗糖却使极性环境中的色氨酸残基(Trppolar)周围微环境的极性继续增大。它们均会使色氨酸残基邻近的具有淬灭活性的蛋白质的位置和/或方向有所变化。同时,甘油和蔗糖的作用也会导致PSI的疏水性增加。

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A novel strain, D3(T), isolated from a field-soil sample obtained from Anhui Province, PR China, was characterized taxonomically by using a polyphasic approach. The cells were Gram-negative, yellow-pigmented rods devoid of flagella, but showing gliding motility. The organism was able to grow at 5-37 degrees C and at pH 4.0-10.0. A comparative 16S rRNA gene sequence analysis indicated that strain D3(T) is a member of the genus Flavobacterium, sharing highest sequence similarity with the type strain of Flavobacterium defluvii (96.7 %). The major isoprenoid quinone was MK-6 and the predominant fatty acids were iso-C-15:0, summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH) and C-16:0. The DNA G + C content was 31.4 mol%. On the basis of phylogenetic and phenotypic data, strain D3(T) represents a novel species within the genus Flavobacterium, for which the name Flavobacterium anhuiense sp. nov. is proposed. The type strain is D3(T) (=KCTC 22128(T)= CGIVICC 1.6859(T)).

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Aim: To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. Methods: Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. The spermatozoa were frozen in straws by liquid nitrogen vapor using egg-yolk-free Tes-Tris (mTTE) synthetic extender and glycerol as cryoprotectant. The effects of glycerol concentration (1%,3%, 5%, 10% and 15% [v/v]) and its equilibration time (10 min, 30 min, 60 min and 90 min) on post-thaw spermatozoa were examined by sperm motility and sperm head membrane integrity. Results: The post-thaw motility and head membrane integrity of spermatozoa were significantly higher (P < 0.05) for 5% glycerol (42.95 +/- 2.55 and 50.39 +/- 2.42, respectively) than those of the other groups (1%: 19.19 +/- 3.22 and 24.84 +/- 3.64; 3%: 34.23 +/- 3.43 and 41.37 +/- 3.42; 10%: 15.68 +/- 2.36 and 21.39 +/- 3.14; 15%: 7.47 +/- 1.44 and 12.90 +/- 2.18). The parameters for 30 min equilibration (42.95 2.55 and 50.39 2.42) were better (P < 0.05) than those of the other groups (10 min: 31.33 +/- 3.06 and 38. 98 +/- 3.31; 60 min: 32.49 +/- 3.86 and 40.01 +/- 4.18; 90 min: 31.16 +/- 3.66 and 38.30 +/- 3.78). Five percent glycerol and 30 min equilibration yielded the highest post-thaw sperm motility and head membrane integrity. Conclusion: Cynomolgus monkey spermatozoa can be successfully cryopreserved in a chemically defined extender, which is related to the concentration and the equilibration time of glycerol.

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The cryoprotective effects of 11 different extenders, TTE, DM, mDM, LG-DM, G-DM, TCG, TEST, TSM, Test-M, Test-H, and LM, on sperm cryopreservation of cynomolgus monkey (Macaca fascicularis) have been compared with glycerol as cryoprotectant. Sperm motility, plasma membrane, and acrosomal integrity were examined to evaluate frozen-thawed sperm function. The results showed that TTE, DM, mDM, LG-DM, G-DM, and TCG exhibited the best and similar protective efficiencies for cynomolgus monkey sperm cryopreservation in terms of sperm motility and plasma membrane integrity (P > .05). The acrosomal integrity for spermatozoa cryopreserved in TCG was statistically lower than that of TTE, DM, mDM, LG-DM, and G-DM (P < .05) but was significantly higher than that of TEST, TSM, Test-M, Test-H, and LM (P < .05). The postthaw sperm motility for 5 other extenders (TEST, TSM, Test-M, Test-H, and LIVI) did not exceed 30%, and the 3 sperm parameters evaluated for them were significantly lower than that of TTE, DM, mDM, LG-DM, G-DM, and TCG (P < .05). On the basis of these findings, 5 commonly used permeating cryoprotectants, glycerol, ethylene glycol, dimethyl sulfoxide, acetamide and propylene glycol have further been tested for their effectiveness on sperm cryopreservation in extenders of TTE, DM, mDM, LG-DM, G-DM, and TCG. The results showed that the sperm cryoprotective efficiencies of glycerol and ethylene glycol were similar and best among 5 permeating cryoprotectant treatments (P > .05). Dimethyl sulfoxide or acetamide resulted in average cryoprotection for cynomolgus monkey spermatozoa: poorer than glycerol or ethylene glycol but better than that of propylene glycol (P < .05). In addition, the action of permeating cryoprotectant appeared to be independent of extenders. The results in the present study demonstrate that 1) TTE, DM, mDM, LG-DM, G-DM, and TCG are excellent extenders and suitable for cynomolgus monkey sperm cryopreservation; 2) the mechanism of action of permeating cryoprotectants are not affected by extender composition; 3) ethylene glycol has a similar cryoprotective efficacy to glycerol that makes it a successful cryoprotectant for sperm cryopreservation in cynomolgus monkeys.

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Ejaculated spermatozoa from cynomolgus monkeys and rhesus monkeys were frozen in straws with six different extenders (TTE, DM, mDM, LG-DM, G-DM, and TCG) containing glycerol. Sperm motility and head membrane and acrosomal integrity were evaluated after fr

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Clinorotation experiments were established to simulate microgravity on ground. It was found that there were obvious changes of Dunaliella salina FACHB435 cells and their metabolic characteristics during clinorotation. The changes included the increases of glycerol content, the rate of H+ secretion and PM H+-ATPase activity, and the decrease of ratio of the plasma membrane (PM) phospholipid to PM protein. These results indicated that microgravity was a stress environment to Dunaliella salina. It is deduced that it would be possible to attribute the effect of microgravity on algal cells to the secondary activation of water stress.