遗传变异与修复机制的量子观点

根据一种使得量子可以完全克隆的机制——量子半保留克隆机制,并以量子相干态可以半保留克隆为基础,作了推广到研究生物DNA分子克隆上的尝试,提出了量子半保留克隆、量子涨落与量子压缩相干态可以作为分别研究生物的遗传、变异与修复机制的可行性基础.研究指出:细胞分裂事件或者细胞死亡事件服从泊松分布;DNA复制的过程中存在着自发的、不可避免的出错几率,相对大小为平均的基因数乘以4π之后的倒数(该公式的计算与实验结果十分吻合);存在修复机制,由此导致了生物体的特殊基因座不同的自发突变频率.     

高等植物体内激子相干迁移与俘获

依据所建立的色素分子排列和取向的新型结构模型,利用激发能传递的广义主方程理论,提出了高等植物体内激子相干迁移与俘获的点阵理论,研究了静态荧光量子产额、定态能量传递速率和荧光强度的变化规律。指出激子相干迁移有助于活体的激发能转移与俘获,并且它有可能是活体内激子寿命的限制因素之一。     

天然的氮肥工厂——豆科植物的根瘤

氮是一切生物的重要构成元素。空气中存在着大量的分子态氮,约占空气成分的80％,估计整个地球大气层中有4,000万亿吨分子态氮,可惜,这么多的分子态氮,除了少数微生物外,大多数生物都不能利用,植物只能从土壤中吸收结合态氮,合成自己的蛋白质一类的含氮化合物,而动物和人以植物为食物,摄取植物中的含氮化合物,合成自己的蛋白质一类的有机氮化合物。那么土壤中的结合态氮又从什么地方来的呢?土壤中的氮化合物,不是土壤本身     

肌球蛋白工作循环的一个新模型

分析总结关于分子马达肌球蛋白的最新研究结果,给出一个新的肌球蛋白工作循环的机械化学偶联模型.从新模型出发,用一组化学动力学方程描述肌肉中大量肌球蛋白的集体工作行为.利用动力学方程的非平衡定态解,并结合Pate和Cooke的实验结果得到了力作为变量的肌肉态方程.理论结果同热力学原理一致,与传统的肌肉收缩理论有一定区别.根据肌肉的特殊结构,对肌肉态方程做了进一步讨论.     

光学相干层析分子成像方法初探

介绍了分子对比剂在光学相干层析成像(optical coherence tom ography,OCT)技术中的研究现状,概述了迄今出现的几种不同的光学相干层析分子成像方法(m olecu lar contrast OCT,简称为MCOCT),讨论了MCOCT的几个重要的实际问题:对比剂的选择范围、激发光强的限制、各种方法灵敏度比较以及MCOCT应用于临床与生物学领域需要考虑的因素。     

氮循环浅析

1　氮循环自然界中的氮素物质以 3种形式存在 ,即 :有机态氮 :据估计 ,地球上蕴藏的有机态氮至少有 2 0 0～ 2 50亿 t;无机态氮 :铵盐、硝酸盐 ,约为有机态氮总量的 1% ;分子态氮 :空气中大约 79%是氮气 ,整个大气层中的含氮量是极其巨大的。其中含量特别多的有机态氮和分子态氮 ,植物都不能直接利用。但是在自然界 ,通过微生物及人类的生产活动 ,以上 3种氮素物质可以相互转化。所谓氮循环就是指氮气、无机氮化合物、有机氮化合物在自然界中相互转化过程的总称 ,包括氨化作用、硝化作用、反硝化作用、固氮作用以及有机氮化合物的合成等。氮…     

萤火虫荧光素酶单克隆抗体的制备与抗原决定簇的研究

以大肠杆菌表达的萤火虫荧光素酶 (fireflyluciferase)为抗原 ,免疫小鼠并进一步筛选与克隆 ,共得到 6株单克隆抗体 .制备腹水并纯化获得抗体后 ,对这 6株抗体与天然态和热变性态蛋白质以及蛋白酶解片段的结合性质进行了鉴定 .认为这 6株抗体的抗原决定簇都是顺序决定簇 .发现其中有 2株单抗与热变性态蛋白质及酶解片段的结合能力较强 ,而不与天然态蛋白质结合 ,其抗原决定簇可能是位于蛋白质内部的肽段 .另外 4株抗体既可与热变性态蛋白质以及酶解片段结合 ,也可与天然态蛋白质结合 ,其抗原决定簇可能位于蛋白质分子表面 .     

水合溶菌酶及其热稳定性的NMR研究

本文用90MHz脉冲NMB波谱仪记录了具不同含水量的溶菌酶的质子宽谱线NMR谱图及自由感应衰减曲线,并记录了水合度为0.10及0.19克水/克溶菌酶的溶菌酶样品从室温到热变性温度范围内的谱图.用线宽参量随水合度及温度的变化讨论溶菌酶在水合及热变性过程中溶菌酶分子及水分子运动性的变化.结果表明,溶菌酶分子及水分子的运动性与水合溶菌酶中的水含量密切相关;低水含量的水合溶菌酶在热变性过程中酶分子运动性的变化经历了两个转变,分别对应于酶分子间的解缔合及分子内的解旋.     

医学影像技术在心脑血管疾病诊断和预防中的应用

<正>文章阐述了多模态医学影像技术在心脑血管疾病诊断和预防中的应用,有创的医学影像技术(包括血管造影、血管内超声、光学相干断层扫描、光声成像等)和无创的医学影像技术(包括超声、MRI、CT、分子影像技术等)可用于展示动脉粥样硬化和斑块的内部结构特征和功能,及其发展过程。未来。医学影像技术的挑战在于发展具有高敏感度的高分辨率成像技术,客观准确地评估易损斑块的形态结构和成分以及病理生物标记物。     

生物分子在溶液中的构象和动力学的自旋-晶格驰豫研究 Ⅰ.丙氨酸

对丙氨酸在水溶液中的构象阳动力学进行了~(13)C自旋—晶格弛豫研究.它的C_α和C_β都有完全的核奥佛好塞效应(NOE),但弛豫特性有明显差异;表明它的甲基在丙氨酸分子整体作各向同性重取向运动的同时绕C_α—C_β键快速旋转.根据这个转动扩散模型,利用实验测定的自旋—晶格弛豫时间和溶液粘度计算了丙氨酸在不同pH值下的体积.对它的体积随离子态的变化,从丙氨酸分子内和丙氨酸间以及丙氨酸与水相互作用加以讨论.此外,还得出了丙氨酸在溶液中作整体运动和甲基内旋转的势垒.以及与之结合的水分子数.     

Antibiotics in the treatment of wounds in the victims of the earthquake in the Armenian SSR

Purulent wounds in 88 victims of the Armenian earthquake with the syndrome of long-term squeezing were examined microbiologically and the experience with using antimicrobial drugs for their treatment was analyzed. In all the cases microbial associations were detected, coliform and nonfermenting gram-negative bacilli, enterococci, anaerobes and yeast-like fungi being isolated from 80, 20, 15 and 25 per cent of the patients respectively. 130 bacterial strains were studied in detail. 80 to 100 per cent of the bacterial isolates were resistant to the antibiotics routinely used in surgical practice, i.e. benzylpenicillin, tetracycline, levomycetin, kanamycin, cephalothin and cefazolin and highly sensitive to new antimicrobial drugs belonging to ureidopenicillins (mezlocillin), quinolones (ciprofloxacin) and cephalosporins of the 3rd generation (cefoperazone and ceftazidime). Retrospective estimation of the antibiotic therapy revealed its inadequacy in 55.7 per cent of the patients for the most part because of the isolates resistance. The 19 variants of the antibiotic use prescribed by the physicians mainly included penicillins, aminoglycosides and their combinations (in 67.2 per cent of the cases). The use of the highly efficient drugs of the groups of ureidopenicillins and quinolones was extremely rare which was likely due to lacking of information on the drugs.     

Histogenesis of the taste buds of the vallate papilla in the in the rat in the postnatal stages of development

The developing taste buds of vallate papillae were studied with electron microscope in rats during the first 7 days after birth. Two types of cells--light and dark--are identified in the taste buds of a one day old animal. The apical parts of dark cells are characterized by numerous dark granules. A distinguishing feature of light cells is the presence of synaptic contacts with afferent intragemmal nerves. On the 4th day of development on the top of the apical parts of the cell, a microvillar apparatus is seen to form, which does not yet communicate with the oral cavity. On the 7th day, basal cells appear in the taste buds. Some of these cells are seen mitotically dividing. The differentiated microvillar apparatus now communicates with oral cavity. The structure of the taste buds is getting similar to that in the adults. The structural and functional peculiarities of the developing taste buds are discussed in association with the period of ontogenesis under consideration.     

Changes in the size of the nucleoli of the Purkinje cells in the canine cerebellum in the postresuscitation period

The changes in the size of Purkinje cell (PC) nucleolus in the lateral and medial cerebellum zones were studied in dogs with different degree of neurologic status recovery after clinical death of various etiology and duration. PC always possess one nucleolus in the control and experimental groups. In the case of complete neurologic status recovery of animals the area of PC nucleolus increases in both zones studied, irrespective of the cause of clinical death. In the case of neurologic disorders the increase in PC nucleolus area is clearly expressed only in the medial zone of the cerebellum, being insignificant in the lateral zone. It is suggested that adaptive characteristics of PC are distinct in the two compared zones, which leads to greater PC vulnerability in the lateral zone during deep hypoxia.     

Frequency of the stages in the cycle of the seminiferous epithelium in the rat

This study determined the optimum number of tubules to be counted per testis cross section, and the number of animals per treatment group, when changes in stage frequencies in the cycle of the seminiferous epithelium are criteria for assessing effects of treatment on spermatogenesis. A data base of 9,672 observed and staged tubules was collected from testicular cross sections of 15 Sprague-Dawley rats. A significant variation between animals was found for the frequencies of Stages I, II, IV, VI, VIII, and XIII. Computer simulation was used to randomly select different combinations of animal and tubule numbers from the observed data. Stage frequency means from each simulation experiment were compared statistically to observed mean frequencies. A model that used data from all 14 stages was analyzed. The following conclusions were made: a) a minimum of 200 tubule cross sections/testis is recommended for estimating stage frequencies; b) for a fixed number of tubules scored, the number of animals sampled is more important than the number of tubules per animal in reducing variance; c) to detect a difference of 2 standard deviations from the mean with a 2% error rate and examining 200 tubules/testis, at least 12 animals must be used per group when assessing all 14 stages; d) when individual stages are examined using 10 animals per group, only Stage VII has 80% or greater power of test (alpha = 0.05) to detect a frequency difference; e) pooling stages into 3-4 groups is recommended to improve the power of detecting a treatment difference.     

Psychological Attributes of the Culture of the Ukrainians in the Modern Stage of the Development of Society and Trends in Changes in These Attributes in the Post-Soviet Period

The authors of the article focus on the transition of the former Soviet state of Ukraine to a market economy. One aspect of the analysis is the cultural values and attitudes of the citizens in a new situation. Market economy and entrepreneurship demand new types of motivation and individual values from people. A challenge for social psychology in the country is the further elaboration of methodological basis of research.     

Immunohistochemistry of the cytoskeleton in the excurrent ducts of the testis in birds of the Galloanserae monophyly

The presence, location and degree of immunoexpression of various microfilament (MF) and intermediate filament (IF) systems (actin, cytokeratins, desmin, vimentin) were studied in the excurrent ducts of the testis in sexually mature and active galliform (Japanese quail, domestic fowl, turkey) and anseriform (duck) birds. These proteins were variably expressed between the epithelia and periductal tissue (periductal smooth muscle cell layer and interductal connective tissue) types and between species. Variable heterogeneous co-expression of filament systems was also found in the various duct epithelia and periductal tissue types: co-expression of filament systems was the rule rather than the exception. In the duck, neither vimentin nor cytokeratin was present in any of the tissues, whereas actin and desmin (absent in the rete testis) were co-expressed in the efferent ducts and epididymal duct unit (comprising the ductus conjugens, ductus epididymidis and ductus deferens). Actin, desmin and vimentin were generally co-expressed in the rete testis, efferent ducts and epididymal duct unit of the quail, domestic fowl and turkey, with vimentin being more strongly immunoreactive than actin and desmin in the epididymal duct unit, but more weakly immunoexpressed in the efferent ducts. Cytokeratin was present and co-expressed with actin, desmin and vimentin in the rete testis, efferent ducts and epididymal duct unit of the domestic fowl and turkey, but not in the quail and duck. The periductal smooth muscle cell layer and interductal tissue co-expressed actin, desmin and vimentin variably in all birds. Luminal spermatozoa of both the turkey and duck were immunonegative for all protein systems, whereas those of the quail and domestic fowl co-expressed actin, desmin and vimentin moderately or strongly. The tissues of the reproductive tract of male birds thus contain cytoskeletal protein systems that are variably but mostly co-expressed and whose contractile ability appears necessary and sufficient for transportation through the various excurrent ducts of the voluminous testicular fluid and its high sperm content, characteristic features of male avian reproduction.