蝮蛇毒碱性磷脂酶A_2基因的克隆

从蝮蛇毒腺中抽提总ＲＮＡ．利用人工合成寡核苷酸引物作逆转录,以ｃＤＮＡ为模板进行体外扩增,获得磷脂酶Ａ２（简称ＰＬＡ２）基因,克隆至ｐＢＳ－ｋｓ载体中。通过对３个碱性ＰＬＡ２（简称ＢＰＬＡ２）基因单独克隆分别作ＤＮＡ全序列分析,推导ｐｒｏ－ＢＰＬＡ２由１３８个氨基酸残基构成,与已测定的部分氨基酸序列比较,基本相符。该基因成功的克隆,不仅推导出ＢＰＬＡ２的蛋白质全序列,也为进一步开展蛇毒功能肽蛋白质工程的研究工作打下了良好的基础。     

肿瘤坏死因子α对白血病细胞作用的^31P核磁共振研究

木文用３１Ｐ核磁共振（ＮＭＥ）观察了人淋巴瘤白血病细胞系Ｍｏｌｔ－４和人早幼粒白血病细胞系ＨＬ－６０的细胞代谢。Ｍｏｌｔ－４和ＨＬ－６０细胞系的３１Ｐ谱主要由磷酸单酯、无机磷（Ｐｉ）、双磷酸双酯、ＡＴＰ的共振峰组成。３１Ｐ谱显示Ｍｏｌｔ－４细胞在受肿瘤坏死因子α（ＴＮＦ－α）作用后,ＡＴＰ／Ｐｉ比值降低。ＨＬ－６０细胞在受ＴＮＦ－α作用后,ＡＴＰ减少。３１Ｐ－ＮＭＲ提供了一种非损伤性研究细胞代谢的重要方法。     

西双版纳石灰岩森林的植物区系地理研究

西双版纳石灰岩森林植物区系经调查有维管束植物１５３科,６４０属,１３９４种及变种,其中,种子植物占１２９科５５８属１２６９种及变种。种子植物的分布区类型组成是热带和主产热带的科占总科数的７１．３％;热带分布属占总属数的９０．１％;热带分布种超过总种数的９０％。热带分布属中又以热带亚洲分布属最多,占总数的３５．３％;热带分布种中则以热带亚洲分布及其变型的种类占总种数的６４．５％为特点。这表明该石灰岩森林植物区系是热带性质的植物区系,属于热带亚洲区系的一部分。由于特殊的地理位置,西双版纳地区是许多典型热带植物的分布北界,同时又是几种地理成分的交汇地带,这又使该石灰岩区系带有明显热带边缘性质和多种地理成分交汇的特点。     

栝楼核糖核酸酶在RNA序列分析中的应用

栝楼核糖核酸酶（RNase TCS）对U碱基具有高度的专一性,在无脲、pH3.5、50℃时,它几乎都在-NP ↓ U-处裂解RNA.它与RNase T1,U₂和有限的碱水解一起,可用于直接的酶法RNA序列分析．     

具收获与投放的三种群Volterra模型的周期轨道

本文在文〔2〕的基础上,研究三维动力系统的Lyapunov分枝问题．放宽了文〔2〕中关于向量场函数的限制,相应地给出从空间闭轨族扰动产生孤立周期解的判定方法．应用判定定理及椭圆函数的积分技巧,研究了具有收获与投放的三种群Volterra模型,得到了存在周期轨道的充分条件．     

DNA fingerprinting of human cell lines using PCR amplification of fragment length polymorphisms

Summary Methods for monitoring cell line identification and authentication include species-specific immunofluorescence, isoenzyme phenotyping, chromosome analysis, and DNA fingerprinting. Most previous studies of DNA fingerprinting of cell lines have used restriction fragment length polymorphism analysis. In this study, we examined the utility of an alternative and simpler method of cell line DNA fingerprinting—polymerase chain reaction (PCR) amplification of fragment length polymorphisms. Fourteen human cell lines previously found by other methods to be either related or disparate were subjected to DNA fingerprinting by PCR amplification of selected fragment length polymorphism loci. Cell identification patterns by this method were concordant with those obtained by isoenzyme phenotyping and restriction fragment length polymorphism-DNA fingerprinting, and were reproducible within and between assays on different DNA extracts of the same cell line. High precision was achieved with electrophoretic separation of amplified DNA products on high resolution agarose or polyacrylamide gels, and with fragment length polymorphism (FLP) loci-specific “allelic ladders” to identify individual FLP alleles. Determination of the composite fingerprint of a cell line at six appropriately chosen fragment length polymorphism loci should achieve a minimum discrimination power of 0.999. The ability of PCR-based fragment length polymorphism DNA fingerprinting to precisely and accurately identify the alleles of different human cell lines at multiple polymorphic fragment length polymorphism loci demonstrates the feasibility of developing a cell line DNA fingerprint reference database as a powerful additional tool for future cell line identification and authentication.     

稻茎毛眼水蝇幼虫田间分布型及抽样技术

根据14丘稻田稻茎毛眼水蝇幼虫调查资料．对其幼虫分布型进行了分析。结果表明;用I、CAm／m、Iσ四种聚集指标法测定,64．3％的田块呈随机分布．28．4%为均匀分布．7．3%为聚集分布。用Iwao平均拥挤度和Taylor幂法则测定．其田间分布型符合随机分布。用频次拟合法测验,50%的田块同时符合渡松、奈曼和负二项分布三种分布型;35．7%的田块同时符合2种分布型。根据该虫田间分布型的特点．制定了相应的序贯抽样技术。     

A NEW SPECIES OF GENUS GRYPOCENTRUS RUTHE (HYMENOPTERA: ICHNEUMONIDAE)

Abstract  One new species of Grypocentrus , namely G. kasparyani , collected in Shenyang, China, is described.     

Caloric Restriction: Conservation of in Vivo Cellular Replicative Capacity Accompanies Life-Span Extension in Mice

In male mice of a long-lived hybrid strain (B6D2F1), long-term 40% caloric restriction (CR) extended both mean and maximum life spans by 36 and 20%, respectively, over that of ad libitum fed (AL) controls. Measurements of entry into S-phase were made in vivo of six different cell types in five different organs using 2-week exposures to BrdU. The labeling index (L.I.) in all organs studied was lower in young CR mice than in young AL fed mice. In most cases, the L.I. in AL mice fell to the levels of that in the CR mice by 13 months of age, and the two groups then remained so through old age. However, when the L.I. was measured in old CR mice which had been placed on the AL diet for a period of 4 weeks (this was termed refeeding (RF)), it was found to be above that of similar age AL or CR mice and almost at the level of young AL mice. This was still true, but to a lesser degree, in a repeat study using an 8-week period of RF. In a separate but parallel in vitro study (companion paper, this volume), the superiority of CR over AL for retention of cellular replication capacity was confirmed by clone size distribution measurements made in several cell types in mice of several age groups. These results indicate that: (1) the rate of cell replication in AL diet mice diminishes greatly by early middle age in all organ sites studied and then plateaus or declines much more slowly; (2) CR broadly preserves in vivo cellular replicative capacity but often requires the energy levels provided by a switch to AL feeding to demonstrate this late in life; (3) accordingly, the replicative deficit in AL fed mice appears to be cumulative and is significant only in old age. The mechanism(s) involved is yet to be discovered but may be related to, or even the same as, that which extends life spans in CR animals. Correspondingly, and with corroborative data from our in vitro companion study, (W. R. Pendergrass et al., 1995. Exp. Cell. Res. 217, 309-316), we suggest that cell populations sustain an accrual of biochemical damage or physiological alterations which increasingly limit their replicative capacity as the animal ages, and that CR reduces the accrual of this damage.     

上海四膜虫接合生殖期间皮层细胞骨架蛋白的研究

本文采用生化抽提,结合电泳及显微技术,对上海四膜虫（Ｔｅｔｒａｈｙｍｅｎａｓｈａｎｇｈａｉｅｎｓｉｓ）Ｓ１皮层细胞骨架（ｃｏｒｔｉｃａｌｃｙｔｏｓｋｅｌｅｔｏｎ）的蛋白组份,及其在接合生殖期间的变化进行了一系列的研究,初次探索了Ｓ１株上海四膜虫在接合生殖中皮细胞骨架的蛋白组份及含量,并分析了它们与间期,接合分开时期同类蛋白相互间的差异,发现在接合生殖时期７６－８８ｋＤ蛋白有突出的表现,而９０ｋＤ和