Deoxyribonucleic acid-protein and deoxyribonucleic acid interstrand cross-links induced in isolated chromatin by hydrogen peroxide and ferrous ethylenediaminetetraacetate chelates

DNA-protein and DNA interstrand cross-links were induced in isolated chromatin after treatment with H2O2 and ferrous ethylenediaminetetraacetate (EDTA). Retention of DNA on membrane filters after heating of chromatin in a dissociating solvent indicated the presence of a stable linkage between DNA and protein. Treatment of protein-free DNA with H2O2/Fe2+-EDTA did not result in enhanced filter retention. Incubation of cross-linked chromatin with proteinase K completely eliminated filter retention. Resistance to S1 nuclease after a denaturation-renaturation cycle was used to detect DNA interstrand cross-links. Heating the treated chromatin at 45 degrees C for 16 h and NaBH4 reduction enhanced the extent of interstrand cross-linking. The following data are consistent with, but do not totally prove, the hypothesis that cross-links are induced by hydroxyl radicals generated in Fenton-type reactions: (1) cross-linking was inhibited by hydroxyl radical scavengers; (2) the degree of inhibition of DNA interstrand cross-links correlated very closely with the rate constants of the scavengers for reaction with hydroxyl radicals; (3) cross-linking was eliminated or greatly reduced by catalase; (4) the extent of cross-linking was directly related to the concentration of Fe2+-EDTA. Partial inhibition of cross-linking by superoxide dismutase indicates that superoxide-driven Fenton chemistry is involved. The data indicate that DNA cross-linking may play a role in the manifestation of the biological activity of agents or systems that generate reactive hydroxyl radicals.     

黑胸大蠊（Periplaneta fuliginosa）病毒的分离及某些特性

从黑胸大蠊(Periplaneta fuliginosa)自然罹病的虫尸中分离得到一株非包涵体病毒。将病毒悬液均匀拌入无菌饲料并供食154～169日龄黑胸大蠊健康若虫时,能使其感染、发病,死亡率可达98％以上。在电子显微镜下观察时,病毒为球形二十面体颗粒,直径约23nm。病毒悬液具有典型核蛋白紫外吸收光谱。病毒用DNase和RNase处理并经吖啶橙染色、二苯胺和苔黑酚试验及甲醛反应证明:该病毒含有单链DNA。以上特性与细小病毒科的特征有点类似。     

MIXED MODEL APPROACHES FOR ESTIMATING GENETIC VARIANCES AND COVARIANCES

The limitations of methods for analysis of variance(ANOVA)in estimating genetic variances are discussed. Among the three methods(maximum likelihood ML, restricted maximum likelihood REML, and minimum norm quadratic unbiased estimation MINQUE)for mixed linear models, MINQUE method is presented with formulae for estimating variance components and covariances components and for predicting genetic effects. Several genetic models, which cannot be appropriately analyzed by ANOVA methods, are introduced in forms of mixed linear models. Genetic models with independent random effects can be analyzed by MINQUE(1)method whieh is a MINQUE method with all prior values setting 1. MINQUE(1)method can give unbiased estimation for variance components and covariance components, and linear unbiased prediction (LUP) for genetic effects. There are more complicate genetic models for plant seeds which involve correlated random effects. MINQUE(0/1)method, which is a MINQUE method with all prior covariances setting 0 and all prior variances setting 1, is suitable for estimating variance and covariance components in these models. Mixed model approaches have advantage over ANOVA methods for the capacity of analyzing unbalanced data and complicated models. Some problems about estimation and hypothesis test by MINQUE method are discussed.     

大鼠实验性脾虚证胃粘膜内分泌细胞变化的免疫组织化学研究

用正常成年雄性Wistar大鼠53只,体重100～150g,分为正常对照组、实验性脾虚组、自然恢复组和四君子汤治疗组。取胃,固定于Bouin液。制成石蜡切片,进行(1)HE染色;(2)免疫组织化学染色,按Sternberger PAP法显示胃泌素细胞(G细胞)、生长抑素细胞(D细胞)和5-HT细胞。根据细胞的免疫反应程度,将细胞分为强阳性、中等阳性和弱阳性三级,每例动物计数三种细胞各1,000个,并计算各级细胞占的百分比;(3)从正常对照组,脾虚组随机选择各5例动物,对D细胞和G细胞进行显微分光光度计的定量测定;(4)由四组动物随机选择各5例,进行G细胞和D细胞密度及G/D细胞比值的测定。本文的观察表明:(1)脾虚组胃粘膜未见明显的组织学变化;(2)内分泌细胞:与对照组相比,脾虚组G细胞和5-HT细胞中,弱阳性细胞增多,表明分泌活动增强;D细胞弱阳性和中等阳性细胞减少,强阳性细胞增多,表明分泌释放减弱,合成增强。与自然恢复组比较,治疗组G细胞和D细胞的分泌活动接近于对照组;5-HT细胞无明显的恢复;(3)显微分光光度计的测定结果与光镜观察一致,脾虚组G细胞胃泌素反应物的含量低于对照组,D细胞内生长抑素反应物的含量高于对照组;(4)脾虚组G细胞密度低于对照组(P<0.01),D细胞密度略高于对照组,G/D细胞比值也低于对照组(P<0.01)。本文结果提示,脾虚证这些内分泌细胞的分泌活动出现异常,可能是导致消化功能紊乱的原因之一。经四君子汤治疗后,内分泌细胞的分泌活动接近于对照组,说明此药对脾虚证有一定的治疗作用。     

土牛膝碱（abidenine）的分离及结构测定

从土牛膝(Achyraanthes bidentata Bl.)的根中分离到一种新的生物碱——土牛膝碱(ubidenine),通过波谱方法测定出土牛膝碱的化学结构为5,6—二氢化—2,3,10,11—四甲氧基—二苯并[a,g]—喹嗪盐(1)。     

去传入神经引起大鼠延髓后角P物质、胆囊收缩素、神经降压肽、亮-脑啡肽变化机制的探讨

去传入神经可引起后角一些肽类变化和含肽的大颗粒小泡以胞吐的形式在非突触部位释放。为了探讨这一作用机制,本文切除一侧刚髭部皮肤,应用免疫组化方法观察并定量分析术后不同时间延髓后角浅层SP、CCK、NT、L-ENK阳性纤维的变化及利多卡因对后角浅层SP的影响。结果显示:术后1小时,延髓后角浅层SP损伤侧较对照侧升高,第3～7天未见显著性减少或升高,第8天开始脱失(P<0.05),第14天脱失更甚,第30天开始恢复,第90～120天基本恢复。CCK变化基本同SP。NT、L-ENK术后不同时间(7～120天),两侧比较未见显著性差异(P>0.05)。应用和多卡因后,后角浅层SP损伤侧较对照侧未见明显减少(P>0.05)。根据上述结果,本文推测:去传入神经导致延髓后角浅层神经肽的变化,可能是神经损伤区(神经瘤或再生芽)产生异常电活动,引起延髓后角浅层神经肽释放的结果。     

新疆药用延胡索资源调查

作者对新疆维吾尔自治区的9个市、县进行了药用延胡索的资源调查,采集植物标本70余份,弄清药用种类主要是3种,即Corydalis glaucescens Regel,C.ledebouriana Kir.et Kar.和C.schanginii(Pall.)Fedtsch.;初步了解了3种药用延胡索植物的分布状况,并对块茎中总生物碱的含量作了分析。     

用细胞融合的方法选育耐高酒精度的酿酒酵母

选择耐高渗透压、耐高酒精度和发酵终了产酒精量较高的黄酒酵母H—1和目前酒精工业生产用菌K号酒精酵母K—1,运用细胞融合技术选育发酵速度快、产酒精量高的工业用酒精酵母.双倍体黄酒酵母H—1和双倍酒精酵母K—1经过产孢前预培养和产孢培养后,蜗牛酶水解子囊孢子壁,离心收集单倍体子囊孢子,培养后得到单倍体黄酒酵母H—2和单倍体酒精酵母K—2.用硫酸二乙醇诱变处理单倍体细胞,得到单倍体黄酒酵母的维生素缺陷型H—3和单倍体酒精酵母的氨塞骏营养缺陷型K—3通过正交试验找出了H—3和K—3原生质体形成及再生的较优条件是:对数生长后期的细胞33℃、0.2%的β—巯基乙醇预处理15分钟,然后4%蜗牛酶作用2小时.用35%聚乙二醇和10mMCaC1_2诱导融合40分钟,于再生基本夹层培养基上培养获得营养互补融合子,并且考查了融合子的遗传稳定性.通过耐酒精度、一发酵速度和最终产酒精量的测定,筛选出融合子HK—6.HK—6与生产用K号酒精酵母相比,发酵速度相接近,而最终产酒精量提高了11%.可耐受16%的酒精度.     

长白山区瓦蛛属三新纪录种（蜘蛛目：皿蛛科：微蛛亚科）

本文记述了我国瓦蛛属三新纪录种,即突褶瓦蛛Walckenaeria sounkyoensis、钉角瓦蛛Walckenaeria claviornis、霍氏瓦蛛Walckenaeria holmi。本文量度单位:mm。标本保存在长春市白求恩医科大学生物教研室。