丝裂素活化蛋白激酶参与内皮素刺激的兔主动脉平滑肌细胞增生

内皮素（ｅｎｄｏｔｈｅｌｉｎ,ＥＴ）是已知的体内活性最强的缩血管物质,其缩血管作用由Ｇ蛋白偶联受体所介导。但ＥＴ强大的促血管平滑肌细胞（ＶＳＭＣ）增生效应的机理尚未完全阐明。本研究选用培养的兔胸主动脉ＶＳＭＣ,探讨丝裂素活化蛋白激酶（ＭＡＰＫ）在ＥＴ促细胞增生中的作用。结果表明：ＥＴ－１呈时间和浓度依赖性地促进细胞摄取￣３Ｈ－ＴｄＲ和激活ＭＡＰＫ,此作用可被蛋白激酶Ｃ（ｐｒｏｔｅｉｎｋｉｎａｓｅＣ,ＰＫＣ）抑制剂Ｓｔａｕｒｏｓｐｏｒｉｎｅ（ＳＴＰ）,Ｈ－７和ＥＴ＿Ａ受体拮抗剂ＢＱ１２３所抑制,但不被酪氨酸激酶抑制剂ＨｅｒｂｉｍｙｃｉｎＡ（Ｈｅｒｂ）所抑制,用ＰＫＣ激动剂ＰＭＡ（Ｐｈｏｒｂｏｌｍｙｒｉｓｔａｔｅａｃｅｔａｔｅ）预处理ＶＳＭＣ,使其ＰＫＣ活性下调,可显著减弱ＥＴ－１对ＭＡＰＫ的激活能力。本结果提示：（１）ＭＡＰＫ参与ＥＴ－１所致的ＶＳＭＣ增生;（２）ＥＴ－１促细胞增生与激活ＭＡＰＫ的作用是由ＥＴ＿Ａ受体和ＰＫＣ介导的。     

正常小鼠高频心电图时域值和功率谱的研究

本文用南京新博公司生产的ＮＨＥ－１０００型心电高频信息检测分析仪研究了正常小鼠（昆明种）高频心电图（ＨＦ－ＥＣＧ）的时域值和ＱＲＳ波群的功率谱。主要结果如下（以正导为例,－Ｘ±ＳＤ）：心率６０３±８８次／ｍｉｎ（ｎ＝７４）;Ｐ－Ｒ间期相对较长。为３４．９±４．７ｍｓ（ｎ＝５８）,占心动周期的３４．９±４．９％,这与人类有很大的不同;ＱＲＳ波宽９．２±１．２ｍｓ,占心动周期的９．２±１．４％（ｎ＝７４）,这一结果与以前的文献报道相差较大。Ｔ波宽１０．３±３．２ｍｓ,占心动周期的１０．３±３．２％;Ｑ－Ｔ间期１９．４±３．２ｍｓ,占心动周期的１９．５±３．６％;ＱＲＳ波群峰－峰值（Ｖｐ－ｐ）为１．４５６±０．４８０ｍＶ;Ｔ波高０．３３６±０．１１５ｍＶ;７３只动物Ⅱ导联高频切迹总数只有３个,扭挫２６个。Ⅱ导联ＱＲＳ波群的功率谱特点：０—８０Ｈｚ的相对能量为４５．４８±１５．３２％;８０—２００Ｈｚ为４３．９７±９．９５％;２００—３００Ｈｚ为８．８９±７．３８％;３００—１０００Ｈｚ为１．６６±２．７４％。     

几种昆虫生长调节剂对家白蚁的毒效试验

在室内条件下测定了卡死克、抑太保、灭幼豚3号、爱力螨克和扑虱灵五种昆虫生长调节剂对家白蚁的毒杀效果。初步筛选结果表明：卡死克、抑太保和爱力螨克对家白蚁的毒杀效果均较好,家白蚁对爱力螨克尤其敏感。2．30pm。yL爱力螨克、327．36pm0VL、卡死克和369．80V＊wL抑太保处理白蚁5～6天后,其死亡率可达100％。忌避性试验表明：卡死克、抑太保和爱力螨克对家白蚁均无明显的驱避作用。     

Cold acclimation and photoinhibition of photosynthesis in Scots pine

Cold acclimation of Scots pine did not affect the susceptibility of photosynthesis to photoinhibition. Cold acclimation did however cause a suppression of the rate of CO₂ uptake, and at given light and temperature conditions a larger fraction of the photosystem II reaction centres were closed in cold-acclimated than in nonacclimated pine. Therefore, when assayed at the level of photosystem II reaction centres, i.e. in relation to the degree of photosystem closure, cold acclimation caused a significant increase in resistance to photoinhibition; at given levels of photosystem II closure the resistance to photoinhibition was higher after cold acclimation. This was particularly evident in measurements at 20° C. The amounts and activities of the majority of analyzed active oxygen scavengers were higher after cold acclimation. We suggest that this increase in protective enzymes and compounds, particularly Superoxide dismutase, ascorbate peroxidase, glutathione reductase and ascorbate of the chloroplasts, enables Scots pine to avoid excessive photoinhibition of photosynthesis despite partial suppression of photosynthesis upon cold acclimation. An increased capacity for light-induced de-epoxidation of violaxanthin to zeaxanthin upon cold acclimation may also be of significance.Abbreviations APX ascorbate peroxidase - DHA dehydroascorbate - DHAR dehydroascorbate reductase - Fm maximal fluorescence when all reaction centres are closed - Fv/Fm maximum photochemical yield of PSII - GR glutathione reductase - GSH reduced glutathione - Je rate of photosynthetic electron transport - MDAR monodehydroascorbate reductase - q_N nonphotochemical quenching of fluorescence - q_P photochemical quenching of fluorescence - SOD superoxide dismutase This work was supported by the Swedish Natural Science Research Council and the National Natural Science Foundation of China.     

中华双腔吸虫精子发生的超微结构研究

应用透射电镜技术,研究中华双腔吸虫的精子发生,并与其它复殖吸虫进行比较,提出了复殖吸虫精子发生的一般过程,结果显示它与大多数复殖吸虫精子发生的超微结构相似,原始的精原细胞经过次有丝分裂,两次减数分裂成为精细胞,它经过分化,形态变化后成为成熟精子,精子形成共分为六个阶段。其中形成共分为六个阶段,其中有以下首次报道的特征,（１）中央胞持区的生长速度在开始时比鞭毛裂快;（２）在鞭毛与中央胞质区融合前,线     

Analysis of Lactobacillus phages and bacteriocins in American dairy products and characterization of a phage isolated from yogurt.

Yogurt and acidophilus milk that contain Lactobacillus acidophilus could promote human health because L. acidophilus can inhibit enteric and food-borne microbial pathogens. To evaluate the stability of diary L. acidophilus cultures, we studied whether some diary lactobacilli could be inhibited by phages or bacteriocins released by other dairy lactobacilli. From 20 yogurts and two acidophilus milks purchased at local food markets, 38 Lactobacillus strains were isolated. Eight Lactobacillus type strains were used as controls. With mitomycin induction and agar spot assay, phages and bacteriocins were isolated from these strains and their activities were analyzed. Lactobacillus strains from 11 yogurts released phages, while the strains from most of the remaining products released bacteriocins. One phage, designated phi y8, was characterized. It was spontaneously released from its host strain L. acidophilus Y8, at a rate of about 10(4)/ml. This phage lysed nine other dairy Lactobacillus strains tested. It had a burst size of 100, an elongated prolate head of 39 by 130 nm, a long, flexible but noncontractile tail of 300 nm, and a 54.3-kb linear double-stranded DNA. DNA fingerprinting analysis indicated that L. acidophilus phages of nine yogurts in this study belonged to the same type as phi y8. Although they may be sensitive to bacteriocins, all lysogens resisted further phage attacks, whereas most nonlysogens were sensitive to both phages and bacteriocins. Therefore, Lacotbacillus cultures of some American yogurts and acidophilus milks may be unstable or unsafe because they can either be inhibited by phages or bacteriocins or release them to inhibit lactobacilli or other diary products.     

Is there an error correcting code in the base sequence in DNA?

Modern methods of encoding information into digital form include error check digits that are functions of the other information digits. When digital information is transmitted, the values of the error check digits can be computed from the information digits to determine whether the information has been received accurately. These error correcting codes make it possible to detect and correct common errors in transmission. The sequence of bases in DNA is also a digital code consisting of four symbols: A, C, G, and T. Does DNA also contain an error correcting code? Such a code would allow repair enzymes to protect the fidelity of nonreplicating DNA and increase the accuracy of replication. If a linear block error correcting code is present in DNA then some bases would be a linear function of the other bases in each set of bases. We developed an efficient procedure to determine whether such an error correcting code is present in the base sequence. We illustrate the use of this procedure by using it to analyze the lac operon and the gene for cytochrome c. These genes do not appear to contain such a simple error correcting code.     

甜菜碱醛脱氢酶在菠菜叶细胞中的定位

将菠菜叶片匀浆后．用差速离心和梯度率心分离叶绿体、过氧物酶体、微粒体等细胞器和１０００００×ｇ上清法部分。用酶活测定法测定各部分甜菜碱醛脱氢酶（ＢＡＤＨ）的活性;用免疫扩散法鉴定各组分的ＢＡＤＨ。除叶绿体外,过氧物酶体、微粒体．以及１０００００×ｇ上清液中也存在ＢＡＤＨ。     

用蛋白质工程方法改变葡萄糖异构酶最适pH和最适温度

用寡核苷酸诱导的定点突变方法构建了葡萄糖异构酶基因的突变体（Ｎ１８４Ｄ和Ａ１９８Ｃ）。含突变体的重组质粒ｐＴＫＤ－ＧＩ１（Ｎ１８４Ｄ）和ｐＴＫＤ－ＧＩ２（Ａ１９８ｃ）在Ｅ．ｃｏｌｉＫ３８菌株中表达,用ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ ＦＦ和Ｓｅｐｈａｃｒｙｌ Ｓ－３００ＨＲ柱层析分离纯化突变酶。与野生型葡萄糖异构酶比较实验表明：（１）突变酶Ｎ１８４Ｄ的最适ｐＨ值下降了１个单位;等电点下降了０．６个单位