肾素－血管紧张素系统──应激激素反应系统

各种急性与慢性应激时,循环血中及脑、心血管、肾腺等组织中血管紧张素Ⅱ（ＡⅡ）显著增多;人剧烈运动后血浆ＡⅡ与皮质醇一样均剧烈增加,在慢性应激性高血压动物循环及组织中,ＡⅡ含量持续地增高。还发现高浓度ＡⅡ对肾上腺糖皮质激素的分泌有直接的刺激作用,而组织ＡⅡ增多又受肾上腺素能β受体的激发。根据近年来的系列工作,并结合文献,我们认为ＡⅡ是一种重要的应激激素;肾素－血管紧张素系统是一个应激激素反应系统;它与经典的应激激素反应系统,下丘脑－垂体－肾上腺皮质系统及交感－肾上腺髓质系统也存在着密切的关系。     

黄皮种子发育过程中脱水敏感性与细胞膜透性的关系

黄皮（Ｃｌａｕｓｅｎａ ｌａｎｓｉｕｍ （Ｌｏｕｒ．） Ｓｋｅｅｌｓ）胚轴与完整种子的发育模式以及发育中电解质渗漏率变化有些不同． 种子生理成熟前、后的胚轴对脱水的反应也不同,前者经轻微脱水可提高萌发率和活力指数,后者不耐任何程度的脱水．活力指数的急剧下降伴随着电解质渗漏率的迅速上升．实验表明,黄皮种子在发育过程中没有形成耐脱水性． 细胞膜透性变化可反映脱水对种子的伤害程度     

可育的抗除草剂溴苯腈转基因小麦

报道了采用微粒轰击（Ｍｉｃｒｏｐｒｏｊｅｃｔｉｌｅ ｂｏｍ ｂａｒｄｍ ｅｎｔ） 幼胚将除草剂抗性基因导入小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ Ｌ．）的转化研究。实验共使用了１３ 个小麦品种, 从开花后１４～１８ ｄ 的籽粒中剥取幼胚, 植物表达质粒含有ＣａＭＶ ３５Ｓ启动子控制的除草剂溴苯腈抗性基因ｂｘｎ 以及筛选标记基因ＮＴＰⅡ。采用高压放电基因枪,用质粒ＤＮＡ 包被的钨粒轰击预培养３ ｄ 的幼胚。在含有卡那霉素类似物ｇｅｎｅｔｉｃｉｎ Ｇ４１８ｓｕｌｐｈａｔｅ 的ＭＳ培养基上, 经过多步骤筛选和分化, 从８００ 多个幼胚中获得了１６ 株转化苗。除草剂抗性鉴定和Ｓｏｕｔｈｅｒｎ 杂交分析证明, 其中４ 株为转基因植物,具有溴苯腈抗性, 并且自交可育。转化工作从分离幼胚到转化苗鉴定完毕, 最短时间为６ 个月, 因此, 该方法是一项快速有效的基因导入技术     

水稻幼芽细胞生物膜上的赤霉素结合蛋白的结合特性

在水稻 (Oryza sativa)幼芽中存在膜结合的赤霉素结合蛋白 ,其与 GA3 结合的平衡解离常数(Kd)为 6.5× 1 0 -8mol/ L,总浓度为 0 .3 pmol· mg-1 蛋白质。结合蛋白与 GA3 结合活力在 0℃时比 2 5℃时高 1 4 0 %。它与 GA3 结合的最适 p H为 5。 GA3 与此结合蛋白的结合量随反应时间延长而增加 ,1 h达最大值 ,以后又逐渐下降。 IAA、ABA可与 GA3 竞争赤霉素结合蛋白。     

己酸菌LⅡ己酸发酵过程中生理及代谢特点

在了解了产己酸细菌ＬＩＩ的发酵最适条件的基础上,进一步对己酸发酵过程中的生理及代谢特性作了较详细的分析。结果表明,在己酸发酵过程中除产生正常代谢产物己酸外,还产生丁酸、乙酸、戊酸等其它酸类和甲烷,氢气和ＣＯ_２等气体。用１—^１３Ｃ－乙酸钠和未标记的乙醇作为底物发酵,用色质联用仪（ＧＣ／ＭＳ）分析,结果表明：在己酸合成中碳的来源为乙醇和乙酸,中间代谢产物为丁酸。     

从玉米胚中大量制备植物钙调素

从每公斤萌发２４ｈ的玉米胚丙酮粉中可提纯得６３ｍｇ的钙调素（ＣａＭ）,这是目前从每公斤植物材料中所提纯得ＣａＭ的最高记录。对其理化性质的研究表明,玉米胚ＣａＭ 有较高的生物学活性,能较好地激活磷酸二酯酶,其紫色吸收光谱,ＳＤＳ－ＰＡＧＥ电泳行为及氨基酸组成与其它的植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ的适宜材料。     

华东植物区系成分与日本植物间的联系

华东和日本两地为东亚地区重组成部分,同属于中国－日本森林植物亚区。两地植区物系成具有较高的相似性。两地共有连香树科（Ｃｒｃｉｄｉｐｈｙｌｌａｃｅａｅ）、三尖杉科（Ｃｅｐｈａｌｏｔａｃｅａｅ）、领春木科（Ｅｕｐｔｅｌｅａｃｅａｅ）、旌节花科ǎ樱簦幔悖瑁酰颍幔悖澹幔澹┑榷翘赜锌啤;腿毡玖降毓灿惺粼迹叮福岸嗍簟Ｈ缌迹ǎ茫颍穑簦铮恚澹颍椋幔⑺荆ǎ模椋螅幔睿簦瑁酰螅⑿」炊ǎ拢澹颍悖瑁     

Cellobiose-oxidizing enzyme from a newly isolated cellulolytic bacterium Cytophaga sp. LX-7

Summary The cellobiose oxidizing enzyme of the newly isolated cellulolytic bacterium Cytophaga sp. LX-7 was produced extracellularly when grown on cellulose or other saccharides, which was previously noted only in fungi. The enzyme could use not only cellobiose, maltose, glucose and other saccharides but also cellulose as substrates, and use dichlorophenol indophenol and oxygen as electron acceptors.     

细小病毒非结构蛋白转基因小鼠模型建立

将小鼠乳腺癌病毒启动子控制的细小病毒非结构蛋白基因(长5.7kb)氯化铯超速离心,纯化透析后用显微注射法导入C57BL/SJL F_1小鼠受精卵雄核,植入假孕母鼠输卵管,得成活小鼠15只。抽取鼠尾DNA,对其中10只小鼠作PCR和southern blot鉴定,其中4只(40％)整合有目的基因。对首建者B_6()的8只子代小鼠鉴定,3只(37.5％)整合有目的基因。说明导入的目的基因能传代。     

Genetic diversity and its relationship to hybrid performance and heterosis in rice as revealed by PCR-based markers

Ten elite inbred lines (four japonica, six indica), chosen from those widely used in the hybrid rice breeding program at Human Hybrid Rice Research Center in China, were crossed to produce all possible hybrids excluding reciprocals. The 45 F₁ hybrids along with the ten parents were evaluated for eight traits of agronomic importance, including yield potential, in a replicated field trial. The ten parents were analyzed with 100 arbitrary decamer oligonucleotide primers and 22 microsatellite (simple sequence repeats, SSRs) primer sets via polymerase chain reaction (PCR). Out of the 100 random primers used, 74 were informative and amplified 202 non-redundant bands (variants) with a mean of 2.73 bands per polymorphic primer. All 22 microsatellite primer sets representing 23 loci in the rice genome showed polymorphisms among the ten parents and revealed 90 alleles with an average of 3.91 per SSR locus. Cluster analysis based on Nei's genetic distance calculated from the 291 (202 RAPDs, 89 SSRs) non-redundant variants separated the ten parental lines into two major groups that corresponds to indica and japonica subspecies, which is consistent with the pedigree information. Strong heterosis was observed in hybrids for most of the traits examined. For the 43 diallel crosses (excluding 2 crosses not heading), yield potential, its components (including panicles per plant, spikelets per panicle and 1000-grain weight) and their heterosis in F₁ hybrids showed a significant positive correlation with genetic distance. When separate analyses were performed for the three subsets, yield potential and its heterosis showed significant positive correlations with genetic distance for the 15 indica x indica crosses and the 6 japonica x japonica crosses; however, yield potential and its heterosis were not correlated with genetic distance for the 22 indica x japonica crosses. Results indicated that genetic distance measures based on RAPDs and SSRs may be useful for predicting yield potential and heterosis of intra-subspecific hybrids, but not inter-subspecies hybrids.