丁酸钠和pH值对离体蚕豆花药中小孢子有丝分裂的影响

含单核中后期至后期花粉的蚕豆离体花药,经过2mM丁酸钠24小时预处理后,再漂浮培养于pH5.8或7.0的液体培养基。以不经预处理的作为对照。结果如下: 1.培养后9天内,丁酸钠预处理和培养基pH值并不明显影响花粉退化百分率。2.培养初期,pH7.0显著促进小孢子不等分裂。3.丁酸钠预处理抑制培养初期的小孢子有丝分裂,而后又显著增加小孢子均等分裂百分率。4.丁酸钠预处理导致小孢子有丝分裂类型的趋向改变。本文还对丁酸钠导致有丝分裂类型趋向改变的可能原因,进行了讨论。     

青海高原中华双腔吸虫等四种双腔吸虫成熟尾蚴的扫描电镜比较观察

青海高原中华双腔吸虫,矛形双腔吸虫等四种双腔吸虫尾蚴经扫描电镜比较观察显示它们体表具有明显的差别。中华双腔吸虫尾蚴体部末部表皮呈具间隔的纵嵴,矛形双腔吸虫尾蚴在此部位呈如同玉米棒的玉米珠粒,未定名的“B”型和“D”型尾蚴,前者呈海棉状,后者介于矛形双腔和中华双腔的形态之间。这四种尾蚴的口吸盘、腹吸盘及体两侧表皮上,具有触毛及乳突的情况亦不相同。     

Baseline and sodium arsenite-induced sister chromatid exchanges in cultured lymphocytes from patients with Blackfoot disease and healthy persons

Summary A significantly higher frequency of baseline sister chromatid exchange (SCE) was found in the cultured lymphocytes of 13 Blackfoot disease patients (BFP) in comparison with that of healthy persons (HP). Twelve of these BFP consumed well water containing a high concentration of arsenic for 15 years or longer and had switched to drinking tap water 12 years before the time of this study. Sodium arsenite was found to be effective in increasing the SCE frequency and delaying the cell growth of the lymphocytes from both BFP and HP. However, the SCE increment induced by sodium arsenite as well as the progression of the cell divisions in the cultured lymphocytes showed no significant difference between BFP and HP.     

针刺对同时在丘脑束旁核和尾核记录的痛兴奋与痛抑制神经元单位放电的影响

在44只大白鼠上,通过两根玻璃微电极同时引导丘脑束旁核和尾核神经元的放电,观察伤害性刺激作用于坐骨神经和电针“足三里”对两个神经元放电的影响。实验共记录到81对两个神经元的同时放电,其中包括26对痛兴奋、3对痛抑制、28对痛兴奋和痛抑制、24对其他组合类型的神经元放电。实验结果表明:1.从大白鼠尾核可同时记录到痛兴奋和痛抑制两种神经元的电活动,未见痛兴奋和痛抑制神经元的放电型式相互转换。2.同一伤害性刺激可同时引起丘脑束旁核和尾核中的两个痛兴奋神经元兴奋、两个痛抑制神经元抑制、或一个痛兴奋神经元兴奋和另一个痛抑制神经元的抑制。3.电针“足三里”可同时使丘脑束旁核和尾核的痛兴奋神经元兴奋减弱或痛抑制神经元抑制反应减弱(抑制解除)。本工作证明,伤害性刺激可同时影响丘脑束旁核和尾核中痛兴奋和痛抑制神经元的单位放电变化,而电针“足三里”又同时对两核团中痛兴奋和痛抑制神经元的活动具有调整作用。     

杉木人工林水量平衡和蒸散的研究

 本文根据我们严密设计的小集水区径流场连续6年的水文测定数据,进行了杉木人工林水量平衡和蒸散的研究。结果表明：集水区年平均降雨量1065.5mm, 在林冠作用面降雨量的分配中,林冠截留雨量264.6mm,截留率24.8%;穿透过林冠层的雨量799.82mm,树干径流量1.08mm,分别占降雨量的75.1%和0.1%。林内降水到达林地时,在枯枝落叶层这个作用面上净降水进行再分配,其中,地表径流量9.27mm,地下径流量203.00mm,总径流系数0.199。土壤蓄水量月变化较大,但年变化很小,占降雨量的1.2%。系统水量最大的输出是蒸散,每年以气态形式返回大气的水量866.03mm,占降雨量81.3%。在蒸散的水量中,林冠截留雨量的直接物理蒸发量为264.6mm,占总蒸散量的31.6%。     

固定化葡萄糖异构酶最适pH值的调节

用多孔强碱性三乙醇胺基聚苯乙烯树脂作为载体,用CNBr与载体上多羟基作用共价偶联葡萄糖异构酶(GI)。最适偶联条件表明:CNBr量增多,蛋白载量增加,但比活下降。固定化葡萄糖异构酶(IGI)最适反应温度比天然酶提高15℃。并系统地研究了影响IGI活力-pH的曲线的各种因素:用具有不同平均孔径的载体(R=137A,185A,230A,365A)固定化GI,在低离子强度条件下(0.0064mol/L),测定其最适pH值分别7.76,7.56,7.50,8.20。选择平均孔径为230A且具有不同数量三乙醇胺基的载体(0.94,1.05,1.13,1.37mmol/g干胶)分别固定化GI,其最适pH值分别为7.70,7.50,7.46,7.36。     

等彩蝇属五新种(双翅目:丽蝇科)

等彩蝇属的研究,国外做过很多工作,国内近年陆续有报道(方建明、范滋德,1984,1985,1986),本文报道5个新种,3个中国新纪录,均采自云南。模式标本存中国科学院昆明动物研究所。     

Isolation, expression, and mutation of a rabbit skeletal muscle cDNA clone for troponin I. The role of the NH2 terminus of fast skeletal muscle troponin I in its biological activity.

A cDNA for rabbit fast skeletal muscle troponin I (TnI) was isolated and sequenced. The clone contains a coding sequence predicting a 182-amino-acid protein with a molecular mass of 21,162 daltons. The translated sequence is different from that reported by Wilkinson and Grand (Wilkinson, J. M., and Grand, R. J. A. (1978) Nature 271, 31-35) in that Arg-153, Asp-154, and Leu-155 must be inserted into their original sequence. Amino acid sequencing of adult rabbit TnI confirmed this result. In order to investigate the role of the NH2 terminus of TnI in its biological activity, we have expressed a recombinant deletion mutant (TnId57), which lacks residues 1-57, in a bacterial expression system. Both wild type TnI (WTnI) and TnId57 inhibited acto-S1-ATPase activity and this inhibition could be fully reversed by troponin C (TnC) in the presence of Ca2+. Additionally both WTnI and TnId57 bound to an actin affinity column. Thus, both inhibitory actin binding and Ca(2+)-dependent neutralization by TnC were retained in TnId57. TnC affinity chromatography was used to compare the binding of TnI and TnId57 to TnC. Using this method, two types of interaction between TnC and TnI were observed: 1) one which is metal independent (or structural) and 2) one dependent on Ca2+ or Mg2+ binding to the Ca(2+)-Mg2+ sites of TnC. The same experiments with TnId57 demonstrated that the type 1 interaction was weakened, and type 2 binding was lost. This method also revealed an interaction between TnC and TnI which is dependent upon Ca2+ binding to the Ca(2+)-specific sites of TnC and which is retained in TnId57. Taken together, these results suggest that the NH2 terminus of TnI may constitute a Ca(2+)-Mg(2+)-dependent interaction site between TnC and TnI and play, in part, a structural role in maintaining the stability of the troponin complex while the COOH terminus of TnI contains a Ca(2+)-specific site-dependent interaction site for TnC as well as the previously demonstrated Ca(2+)-sensitive inhibitory and actin binding activities.     

Molecular cloning and mapping of phenol degradation genes from Bacillus stearothermophilus FDTP-3 and their expression in Escherichia coli.

Two genes of the meta pathway of phenol degradation were cloned from a phenol-utilizing strain of Bacillus stearothermophilus and were mapped by subcloning and by use of a Tn5 insertion mutation. They code for phenol hydroxylase and catechol 2,3-dioxygenase, respectively. The gene encoding catechol 2,3-dioxygenase, which is more thermostable than catechol 2,3-dioxygenase encoded by the other gene, shares rather limited homology with that from Pseudomonas putida.     

Biosynthesis of the cell surface sialomucin complex of ascites 13762 rat mammary adenocarcinoma cells from a high molecular weight precursor

Cell surfaces of metastatic 13762 ascites rat mammary adenocarcinoma cells are covered with a sialomucin complex composed of the high Mr sialomucin ASGP-1 (approximately 600,000) and a concanavalin A-binding, integral membrane glycoprotein ASGP-2 (120,000). Antibodies prepared against ASGP-2 and deglycosylated ASGP-1 react on immunoblots of ascites cells or their isolated microvilli with the Mr = 120,000 species and the high Mr sialomucin, respectively. No cross-reactivity was observed. Under complex dissociating conditions, anti-ASGP-2 immunoprecipitated primarily components of Mr = 120,000 and about 400,000 from lysates of cells labeled for 1 h with mannose, glucosamine, and threonine. Under similar conditions, anti-ASGP-1 immunoprecipitated the Mr = 400,000 component and a second major labeled component of about 330,000. Pulse-chase labeling with 35S-labeled amino acids followed by immunoprecipitation with anti-ASGP-2 indicated a precursor-product relationship for the Mr = 400,000 component, designated pSMC-1 (precursor, sialomucin complex), and ASGP-2. Similar pulse-chase analyses of threonine-labeled cells using anti-ASGP-1 showed equivalent amounts of immunoprecipitated pSMC-1 and pSMC-2, both of which disappeared with kinetics similar to those observed for pSMC-1 immunoprecipitated with anti-ASGP-2. A precursor-product relationship of both pSMC-1 and pSMC-2 to ASGP-1 was suggested by combined precipitations with anti-ASGP-1 and peanut agglutinin, which precipitates ASGP-1 specifically. Immunoblot and lectin blot analyses indicated that pSMC-1 and pSMC-2 from the immunoprecipitates bind anti-ASGP-2, anti-ASGP-1, and concanavalin A. Moreover, these three components can also be labeled with mannose; the mannose was removed from 30-min pulse-labeled anti-ASGP-2 immunoprecipitates by incubation with endo-beta-N-acetylglucosaminidase H, indicating the presence of only high mannose N-linked oligosaccharides in pSMC-1. One-dimensional peptide maps of 35S-labeled pSMC-1 and Mr = 120,000 ASGP-2 showed several corresponding bands. These results indicate that both ASGP-1 and ASGP-2 can be synthesized from a common high Mr precursor. We propose that complex is formed from pSMC-1 by proteolytic cleavage to yield Mr = 120,000 ASGP-2 plus the precursor to ASGP-1 early in the transit pathway from the endoplasmic reticulum to the cell surface.