GPX－abzyme对受XO／HX系统损伤的心肌线粒体的保护作用

探讨了研制的具有谷胱甘肽过氧化物酶活力的含硒抗体酶（ＧＰＸ－ａｂｚｙｍｅ）对于受损心肌线粒体的保护作用,利用牛的心肌线粒体为实验材料,通过线粒体的膨胀度、脂质过氧化物含量、ＣＣＯ活力变化及电镜观察等几个方面证明ＧＰＸ－ａｂｚｙｍｅ能抵抗ＸＯ／ＨＸ系统产生的自由基的损伤作用,ＥＳＲ研究也表明ＧＰＸ－ａｂｚｙｍｅ能明显降低ＸＯ／ＨＸ损伤系统中的自由基含量。     

THE RELATIONSHIP BETWEEN A FLOWER GALL MIDGE PSEUDAS-PHONDYLIA SP. (DIPTERA: CECIDOMYIIDAE) AND ITS HOST PLANT ACTINIDIA VALVATA*

Abstract Kiwifruit plants, Actinidia sp., are native to subtropical China. The flower-bud gall of A. valvata, which is induced by an undescribed gall midge in the genus Pseud as phond ylia, is valued by the pharmaceutical industry. When studying the biology of the Actinid ia/Pseud as phond ylia interaction in Central-south China we found evidence suggesting that under certain circumstances the gall insect modifies the reproductive mode of the dioecious host plant. Surveys and field experiments in the National Hupingshan Natural Reserve showed a high frequency of galled trees. The density of galled trees varied among valleys and among trees within the valleys. In two valleys, 92% and 75%, respectively, of all trees were attacked, while in a third valley no trees were attacked. When infested, staminate tree only produced galls, whereas pistillate plants produced normal fruits as well as galls. Gall shape differed between male and female trees. Trees with galls tended to produce more fruits than treea without galls. We speculate that this is one of a few documented examples of an insect that induces androdioecy in an otherwise functionally dioecious plant.     

Induction of a Nerve Growth Factor-Sensitive Kinase that Phosphorylates the DNA-Binding Domain of the Orphan Nuclear Receptor NGFI-B

Abstract: Nerve growth factor (NGF) induces the synthesis and the phosphorylation of the orphan nuclear receptor NGFI-B in PC12 cells. Previous work has shown that phosphorylation, by protein kinase A, of a specific serine in the DNA-binding domain inhibits its binding to the NGFI-B response element. Also, cytoplasmic extracts from PC12 cells phosphorylate this serine, and phosphorylation is greater in extracts from cells treated with NGF. The present work describes the induction, identification, and partial purification of a kinase (termed NGFI-B kinase I) from PC12 cell extracts that catalyzes this phosphorylation. Phosphorylation of the DNA-binding domain with this purified preparation inhibits its binding to the NGFI-B response element. The kinase is rapidly activated by treatment of the cells with NGF, and the activation lasts for at least several hours. It also is activated by fibroblast growth factor and epidermal growth factor (EGF), but the activation by EGF is quite transient. The kinase requires Mg²⁺ but will use Mn²⁺. The molecular mass of the kinase is 95–100 kDa, and it is different from protein kinase A, Fos kinase, or pp90 ^rsk . Comparison with a partially purified preparation of cyclic AMP response element-binding protein kinase, however, indicates that the two are either very similar or identical.     

Se和V_E与克山病

以克山病病区粮配成基础饲料,另在基础饲料中分别补充Ｓｅ或ＶＥ,或Ｓｅ＋ＶＥ喂养大鼠,在细胞及亚细胞水平上以Ｃａ代谢为主研究并比较了Ｓｅ和ＶＥ在克山病病因中的作用。测量了心肌细胞和心肌线粒体的Ｃａ代谢及有关指标、心肌线粒体能量转换功能及心肌组织自由基含量。结果表明,在低Ｓｅ病区粮中补充Ｓｅ或ＶＥ均能在一定程度上预防病区粮中致病因素对心肌细胞及线粒体的损伤;并且补充Ｓｅ或ＶＥ均能使心肌组织中自由基含量减少。提示Ｓｅ和ＶＥ是通过清除体内过量自由基预防细胞和线粒体的损伤的。但值得注意的是,实验中所用病区粮ＶＥ含量不低于甚至高于非病区对照粮,在低Ｓｅ情况下,所补ＶＥ的量需要相当大（如本实验中补充２００μｇ／ｇ）才能较明显地预防心肌细胞和心肌线粒体的损伤。通过对这些结果的分析,进一步肯定低Ｓｅ是克山病形成的重要因素之一。     

甘蔗节间伸长过程赤霉素生物合成关键基因的表达及相关植物激素动态变化

以甘蔗(Saccharum officinarum)优良品种桂糖42号(GT42)为研究材料, 分别于未伸长期(9-10叶龄以前) (Ls1)、伸长初期(12-13叶龄) (Ls2)和伸长盛期(15-16叶龄) (Ls3)取甘蔗第2片真叶(自顶部起)对应的节间组织, 测定其赤霉素(GA)、生长素(IAA)、油菜素甾醇(BR)、细胞分裂素(CTK)、乙烯(ETH)和脱落酸(ABA)的含量, 并通过实时荧光定量PCR (qRT-PCR)分析赤霉素合成途径关键基因GA₂₀氧化酶基因(GA20-Oxidase1)、赤霉素受体基因(GID1)和DELLA蛋白编码基因(GAI)的差异表达。结果表明, 在甘蔗伸长期间, GA和IAA含量呈现上升趋势, CTK和ABA含量呈下降趋势, ETH含量先上升后下降, BR含量则变化不明显; GA20-Oxidase1和GID1的表达呈上升趋势, 而GAI的表达则呈下降趋势, 这与相关植物激素的变化基本一致。综上, 甘蔗节间伸长过程主要与GA和IAA相关, 其次为CTK和ABA, 而ETH受到IAA的调控影响节间伸长; 植物激素间通过相互作用调控GA20-Oxidase1、GID1和GAI的表达, 影响GA含量和GA的信号转导过程, 进而影响甘蔗节间的伸长。该研究揭示了甘蔗节间伸长过程中赤霉素生物合成途径和信号转导关键基因的差异表达及植物激素含量的动态变化规律。     

海南植物增补（三）

本文继续报道海南岛新记录的植物,计24个新记录种,4个新记录属。1个新记录科,其中指叶瓶蕨在我国是首次发现。本文引用的标本,全部收藏在中国科学院华南植物研究所标本室(SCBI)。     

成年去胸腺大鼠和老年大鼠肝微粒体混合功能氧化酶及血浆性激素水平的变化

成年去胸腺(ATx)大鼠和老年大鼠肝微粒体混合功能氧化酶(MFO,包括细胞色素P450、氨基比林-N-脱甲基酶)的活力比成年对照大鼠的低,且降低幅度雄性明显大于雌性。雄性ATx大鼠和老年大鼠血浆睾酮(T)水平降低,雌二醇(E_2)水平增高,E_2/T比值明显增高;雌性ATx大鼠和老年大鼠血浆E_2和T水平均降低,E_2/T比值无明显变化。给雄性ATx大鼠皮下注射丙酸睾丸素可使其肝微粒体MFO活力恢复。提示胸腺对肝脏MFO的影响可能是通过性激素介导的。     

Phosphorylation-dependent regulation of phospholipase A2 by G-proteins and Ca2+ in HL60 granulocytes.

We studied the regulation of arachidonic acid (AA) release by guanosine 5'-O-(3-thiotriphosphate (GTP gamma S) and Ca2+ in electropermeabilized HL60 granulocytes. Stimulation of AA release by GTP gamma S and Ca2+ was mediated by phospholipase A2 (PLA2) and required the presence of MgATP (EC50: 100-250 microM). The nucleotide effects were Ca(2+)-dependent (maximal effects detected at 1 microM free cation). UTP and ATP gamma S, which stimulate AA release in intact HL60 granulocytes with potencies and efficacies similar to those of ATP, were ineffective in supporting the effects of GTP gamma S in electropermeabilized cells. Pretreatment with pertussis toxin affected stimulation of AA release by ATP in intact cell, without altering the nucleotide effects in permeabilized cells. We observed the protein kinase C-dependent phosphorylation of PLA2 in permeabilized HL60 granulocytes, together with a correlation between the effects of phorbol esters and staurosporine on this reaction and on AA release. ATP-independent activation of PLA2 by GTP gamma S and/or Ca2+ was measured in subcellular fractions prepared from HL60 granulocytes. These data appear consistent with a model in which PLA2 activity in resting HL60 granulocytes is subjected to an inhibitory constraint that prevents its activation by Ca2+ and G-proteins. Removal of this constraint, either by the protein kinase C-dependent phosphorylation of the enzyme in vivo or physical disruption of the regulatory assembly (e.g. by N2 cavitation), allows its activation by Ca2+ and G-proteins.     

Monte Carlo studies of a model for lipid-gramicidin A bilayers.

This paper presents results of Monte Carlo simulations of a full bilayer of 200 lipid chains and one gramicidin A dimer. Simulations are described for systems with lipid chains of 14, 16, and 18 carbons, respectively. Using accepted potential functions to calculate interactions between all non-hydrogen atoms a Monte Carlo configuration sampling is generated from which order parameter profiles are calculated and specific configurations are displayed. Results are compared with experimental data for lipid-gramicidin bilayers.