A surface mutant (G82R) of a human α-glutathione S-transferase shows decreased thermal stability and a new mode of molecular association in the crystal

A chimeric enzyme (GST121) of the human α-glutathione S-transferases GST1-1 and GST2-2, which has improved catalytic efficiency and thermostability from its wild-type parent proteins, has been crystallized in a space group that is isomorphous with that reported for crystals of GST1-1. However, a single-site (G82R) mutant of GST121, which exhibits a significant reduction both in vitro and in vivo in protein thermostability, forms crystals that are not isomorphous with GST1-1. The mutant protein crystallizes in space group P2₁2₁2₁, with cell dimensions a = 49.5, b = 92.9, c = 115.9 Å, and one dimer per asymmetric unit. Preliminary crystallographic results show that a mutation of the surface residue Gly 82 from a neutral to a charged residue causes new salt bridges to be formed among the GST dimers, suggesting that the G82R mutant might aggregate more readily than does GST121 in solution resulting in a change of its solution properties. © 1994 Wiley-Liss, Inc.     

横纹肌肌原纤维的第三肌丝──肌联蛋白

实验研究证明,在动物横纹肌肌原纤维中,除包含有粗肌丝、细肌丝外,还有纤肌丝的存在,肌联蛋白（肌巨蛋白）是具有挠性的线状蛋白质,分子量为3000 000,长度约为0.9μm,跨越肌原纤维的M－线和Z－线,形成纤肌丝.其生理功能是在粗肌丝装配中具有分子模板作用,并将粗肌丝稳定于肌原纤维肌小节中央以及可参与肌球蛋白活性的调节.     

The persistence of Golgi complexes during cell division in an insect epidermis

The Golgi complexes of animal cells are said to become vesicular during cell division in order to allow the equal partitioning of organelles between daughter cells (Warren, 1985). However, in the epidermis of fifth stage larval Calpodes ethlius (Lepidoptera, Hesperi idae), cutical deposition is concurrent with cell division in preparation for pupation. We therefore looked at the Golgi complexes of these epidermal cells to see if they maintained their interphase form to allow them to continue to function during cell division. Dividing cells were recognized by changes in the nucleus and nuclear envelope, the form of the cell cortex and cell surface, and by the disposition of microtubules. Epidermal Golgi complexes consist of 3-5 cisternae capped by endoplasmic reticulum with transfer vesicles and rings of GC beads next to the cis face, and secretory vesicles on the trans face. Golgi complexes of dividing cells are structurally indistinguishable from those in interphase, their beads are in the rings characteristic of active GCs, and cuticle continues in uninterrupted lamellae above the apical microvilli. The observations suggest that Golgi complexes in dividing insect cells differ from those of most vertebrates by remaining functional through mitosis.     

牛生长激素释放因子的融合表达及其产物的化学加工

通过寡核苷酸引导的定位突变,在人工全合成的第２７位为Ｉｌｅ的牛生长激素释放因子［Ｉｌｅ２７］ｂＧＲＦ（１－４４）ＯＨ基因的５＇端ＡＴＧ后插入Ｔｒｐ密码子序列,并分别了构建了Ｐｌ ｐｒｏｍｏｔｅｒ控制下、以β－半乳糖苷酶和ｐｒｏｔｅｉｎ Ａ结合ＩｇＧ ｄｏｍａｉｎＢ、Ｃ为载体蛋白的融合型基因表达质粒ｐＢＬＥ３１０和ｐＢＬＰＡＥ２Ｄ,在大肠杆菌中得到高效表达。经ＳＤＳ－ＰＡＧＥ分析,表达产物β－Ｇａｌ     

黄麻栽培种圆果种×长果种的种间杂交研究

１９８９—１９９１年对黄麻栽培种圆果种（Ｃｏｒｃｈｏｒｕｓｃａｐｓｕｌａｒｉｓ）和长果种（Ｃ．ｏｌｉｔ－ｏｒｉｕｓ）选用了具有不同茎色和腋芽性状的材料做了６个组合,获得１３４株杂种Ｆ＿１苗。但苗株发根不良,在移栽后两周陆续死亡,最后幸存ＲＲ－５×（ＢＬ×７７－１９）Ｆ＿１组合中两株植株并开花、结果。Ｆ＿１均有腋芽,表现为父本的性状;花果形状偏向母本;茎色红同双亲。这两株的Ｆ＿２,茎色和腋芽性状分离成４种表现型：红茎或青茎有腋芽及红茎或青茎无腋芽。其中红茎有腋芽的生长较快。对种间杂交技术、亲本间的花粉与柱头亲和性、杂交花的胚珠受精情况及染色体构型等方面也作了观察、研究。     

一级吸收药物的生物利用度估计的两点法

本文应用系统分析方法,建立了一种一级吸收药物的生物利用度的简便估计的两点法。这种方法,只需测量血管内和血管外给药后的两个相同时点的血药浓度值。不论该药的处置系统是多少室,均能得到较好的结果。这种方法不仅比目前常用的点一点法和点一面法简单,而且结果更精确。     

津白_3侏儒小鼠垂体前叶生长激素细胞的免疫细胞化学研究

津白_３侏儒小鼠（ｄＷ~ｔ）是１９８２年从津白_３纯系小鼠（ＴＡ_３）中发现,进而培育成侏的变种。本实验应用免疫细胞化学技术,对ｄｗ￣ｔ小鼠垂体前叶生长激素（ＧＨ）细胞进行观察,并根据体视学原理进行定量分析,以探讨ｄｗ~ｔ小鼠是否存在垂体发育缺陷。实验结果显示,ｄｗ~ｔ小鼠ＧＨ细胞的体积密度（Ｖｖ）和数密度（Ｎｖ）值均低于正常对照组,Ｐ＜０．０１～０．００１。表明ｄｗ~ｔ小鼠由于垂体前叶ＧＨ细胞数量减少,导致ＧＨ分泌不足,从而形成侏儒。     

HBIG,无环鸟苷,干扰素联合对慢性乙型肝炎抗病毒效应观察

本文报道血清ＨＢＶ复制标志阳性的慢乙肝５４例,随机分为治疗组及对照组各２７例进行ＨＢＩＧ、无环鸟苷、干扰素联合近、远期抗病毒效应观察。治疗组为无环鸟苷第一周按２５～２０ｍｇ／ｋｇ／ｄ计后改１７～１５ｍｇ／ｋｇ／ｄ×５３天,共６０天;人白细胞干扰素１×１０６Ｕ肌注每周３次×４周,后改１．０×１０６Ｕ肌注每周２次×６周,共１０周;ＨＢＩＧ４００Ｕ肌注隔日１次,共１０周,对照组仅给予一般“保肝”药物。其中治疗组１８例,对照组１９例进行治后半年到２年追踪观察,结果近、远期ＨＢｃＡｇ、ＤＮＡＰ、ＨＢＶ－ＤＮＡ阴转率治疗组均高于对照组,其中治疗组近、远期ＨＢｃＡｇ,ＨＢＶ－ＤＮＡ阴转率均达４０％以上,明显高于对照组（Ｐ＜０．０５～０．０１）,治疗组近、远期各有４例及２例ＨＢｓＡｇ阴转,而对照组则无一例阴转,从近、远期综合抗病毒效应观察,治疗组全阴率分别为３３．３％、４４．４％,而对照组分别为３．７９％及０％,Ｐ＜０．０１,治疗组无明显毒副反应。对比单用无环鸟苷,全阴率３１．８％;无环鸟苷加干扰素两药联合全阴率３７．５％,均有所提高,达到４４．４％,值得进一步研究。     

槟榔（Areca catechu L.）的民族植物学

本文从民族植物学的观点介绍了我国南方各省嚼槟榔的习俗、历史及演变,分析了这个习俗的形成原因及槟榔的药用价值。作者认为咀嚼槟榔有成瘾性,但是否对人的中枢神经系统有损害,必须进一步研究。作者对这种习俗提出了几点看法和建议,对槟榔的开发利用有重要参考价值。