质体醌在两个光系统激发能分配中的功能

用非极性有机溶剂正己烷抽提菠菜类囊体膜,Mg~(2 )调节激发能在两个光系统间的分配效率降低:向抽提过的类囊体膜加入人工合成的PQ类似物PQ_2,有部分恢复Mg~(2 )对能量分配的调节作用,但对类囊体膜表面静电性质不产生影响.向非抽提的类囊体膜加入二溴百里香醌(DBMIB),一种抑制PQ氧化的抑制剂,同样发现DBMIB抑制Mg~(2 )调节激发能分配的效率,但对类囊体膜表面静电性质也不发生影响.以上实验结果表明,PQ对Mg~(2 )诱导激发能在两个光系统间的分配具有调节作用.这种调节作用不依赖于类囊体膜的表面电荷变化,而与PQ的氧化还原状态密切相关.     

弱有机碱对光合磷酸化的影响

类囊体内部介质可被弱有机碱如吡啶、苯胺、咪唑缓冲,致使[H_(in)~ ] 减少,ΛpH幅度降低,光合磷酸化(PSP)反应被抑制,对苯二胺(p—PD)降低ΛpH,但显著促进PSP反应、在MV或PMS系统中均有此现象;在 MV DBMIB;MV DCMU或PMS DBMIB系统中,p—PDH_2重建ΛpH并恢复PSP反应活力。从p—PD(H_2)既具有弱有机碱性质,又可作为电子供体、氢递体,代替QH_2或PQH_2调节电子传递起转移质子的两种作用,解释了p—PD对ΛpH的抑制,却又促进PSP反应的现象。讨论了PSP反应对[H_(in)~ ],ΛpH幅度大小的依赖关系。     

质体醌在两个光系统激发能分配中的功能

用非极性有机溶剂正己烷抽提菠菜类囊体膜,Mg~(2+)调节激发能在两个光系统间的分配效率降低:向抽提过的类囊体膜加入人工合成的PQ类似物PQ_2,有部分恢复Mg~(2+)对能量分配的调节作用,但对类囊体膜表面静电性质不产生影响.向非抽提的类囊体膜加入二溴百里香醌(DBMIB),一种抑制PQ氧化的抑制剂,同样发现DBMIB抑制Mg~(2+)调节激发能分配的效率,但对类囊体膜表面静电性质也不发生影响.以上实验结果表明,PQ对Mg~(2+)诱导激发能在两个光系统间的分配具有调节作用.这种调节作用不依赖于类囊体膜的表面电荷变化,而与PQ的氧化还原状态密切相关.     

光合磷酸化偶联机制的研究——C_4植物鞘细胞与叶肉细胞叶绿体光合磷酸化与高能态的关系

用去除类囊体膜内外质子梯度(⊿H~+)的解联剂氯化铵(NH_4Cl)或尼日利亚菌素(nigericin+KCl),以及去除膜电位(⊿φ)的载离子体短杆菌肽(gramicidin D)和缬氨霉素(valinomycin+KCl)等解联剂,观察和比较了它们对玉米鞘细胞和叶肉细胞叶绿体光合磷酸化(PSP)反应的影响。在恒态照光下,发现氯化铵对叶肉细胞叶绿体光合磷酸化反应的抑制作用比鞘细胞叶绿体光合磷酸化反应要强烈得多。gramicidla D对这两种叶绿体的作用与NH_4Cl作用则相反,它对鞘细胞叶绿体磷酸化反应的抑制远比对叶肉细胞叶绿体磷酸化反应的抑制作用强烈。缬氨霉素对叶肉细胞叶绿体PSP活力无显著的影响,但对鞘细胞叶绿体PSP活力有明显的抑制作用。说明在恒态下这种叶肉细胞叶绿体的PSP反应中驱使ATP形成的PMF主要由(⊿H~+)组成,鞘细胞叶绿体中推动ATP形成的PMF主要组成为⊿φ。叶肉细胞叶绿体在氯化铵和短杆菌肽共同作用下它的PSP反应几乎完全被抑制,而鞘细胞叶绿体的PSP反应还残留为对照的23％。在⊿H~+和⊿φ完全消失的情况下,鞘细胞叶绿体仍能形成相当数量的ATP。这种现象再次说明可能还有一种不以膜内外势差(⊿H~+,⊿φ)形式的膜上高能态存在,这种高能态可直接推动ATP形成。     

光合磷酸化偶联机制的研究寡霉素对PSP、ATP酶和ATP_b-Pi交换反应的作用

在过去工作基础上,我们进一步研究类囊体膜上牢固结合的ATP_b 与Pi 的交换反应和PSP 的关系。主要结果是:①在线粒体中对ATP 酶复合体的疏水蛋白专一敏感的寡霉素,对叶绿体中ATP 的光下形成和水解均表现为抑制,其中对ATP 酶活力的抑制要比对ATP 形成的抑制强烈得多,对核苷酸交换和光下H~ 吸收也有明显的抑制作用(表1)。②去除内源游离核苷酸的叶绿体悬浮液,与Pi(~(31)Pi ~(32)Pi)照光(不外加ADP),发现在适当的寡霉素浓度(20微克/毫克蛋白)下显著促进此系统ATP 中~(32)Pi 参入的数量;并且在所测温度下均促进,温度升高(30℃),促进作用更为明显(表2,3)。③用荧光素酶测定ATP 的方法对上述系统的反应产物进行鉴别,并与~(32)Pi酯化法相比较,证明寡霉素促进的是ATP_b-Pi 交换(图1,2;表4,6)。④ATP_b-Pi 交换反应与类囊体膜的能量转换有密切的关系。这交换反应需光、需辅助因子,也受解联剂的影响(表5),是需能反应。这ATP_b-Pi 交换,较之PSP 受解联剂的影响要小得多,可能它与膜上高能态有更为直接的联系。     

铁氧还素对二溴百里香醌抑制光合电子传递的解抑现象

铁氧还素(Fd)能解除二溴百里香醌(DBMIB)对光合电子传递的抑制作用。DBMIB的抑制效果与反应系统中的Fd和DBMIB的浓度,以及两者混合后的保温时间有关。Fd—DBMIB动态差示吸收光谱显示Fd与DBMIB之间有直接的化学作用。因此,在用DBMIB来研究有Fd参与的光合电子传递实验时,都须注意两者间的直接作用。     

光合磷酸化偶联机制研究——Ⅱ.金霉素对光合磷酸化促进作用的研究

用金霉素溶液处理菠菜离体叶绿体,对循环( PMS)和非循环光合磷酸化( FeCy、MV或BQ DBMIB)均可表现出促进作用,表明它对两个能量保存部位都有促进作用。它能提高磷酸化的偶联程度,增加ADP/O及PC比值。在对光合磷酸化有促进作用的情况下,用两阶段光合磷酸化法测定,它对高能态的积累略有增加或影响不大,但它能显著增加叶绿体的延迟发光。它对叶绿体膜上Mg~(2 )-ATP_(ase)及偶联因子Ca~(2 )-ATP_(ase)活力有抑制。金霉素溶液的荧光强度可被加入偶联因子所提高,这些都表明金霉素至少有一个作用部位与偶联因子有关。文中对它能促进光合磷酸化作用的机理进行了讨论。     

Clotrimazole对叶绿体ATPase功能的影响及其作用部位

clotrimazole能抑制 DTT+光激活的类囊体膜上Mg~(2+)—ATPase的活力。这种抑制属于可逆非竞争性抑制。进一步的实验还表明clotrimazole可以消除 9—AA光下荧光粹灭指示的正常类囊体及DCCD重组残缺膜的跨膜质子梯度。卵磷脂可以减缓 clotrimazole对9—AA荧光粹灭的抑制作用。clotrimazole还能抑制DTT加热激活的游离CF_1 Ca~(2+)—ATPase的活力。根据以上结果我们推测 clotrimazole在类囊体上可能有两个作用部位,一个在类囊体膜脂;另一个在CF_1。     

光系统Ⅱ电子受体p－BQ及DMBQ的耗氧的动态变化

对苯醌（ｐ—ＢＱ）及二甲基对苯醌（ＤＭＢＱ）作为类囊体膜中光系统ＩＩ电子受体时，可同时作为电子递体促进耗氧反应，这个过程在低浓度下即可发生。因耗氧的速率较放氧速率低，所以在氧变化动力学测量开始阶段，耗氧过程为放氧过程所掩盖。ｐ－ＢＱ为４０μｍｏｌ／Ｌ时耗氧活力与放氧活力之比为０．１６，在３００μｍｏｌ／Ｌ时，比值为０．５５。因此，在计算光系统ＩＩ电子传递活力时，不可忽略耗氧活力。耗氧速率随浓度增加而增加。在相同浓度下促进耗氧速率的关系为：而耗氧速率达到饱和的浓度则是：实验表明ｐ－ＢＱ作为电子递体参与耗氧反应的位置不先于ＤＣＭＵ抑制位置。     

寡霉素对叶绿体质子传导的作用

在叶绿体中,寡霉素具有加速类囊体内部质子(H~ in)流出的作用,相应地加速光合磷酸化高能态的暗衰变;寡霉素完全不能恢复叶绿体残缺膜在光下形成膜内外质子浓度梯度的作用,它对H~ in流出的加速,不是由于对类囊体膜透性的影响,而是影响于ATP酶复合体的质子传导。由于这种加速作用,导致类囊体在光下形成的膜内外质子浓度梯度的降低,从而抑制了光合磷酸化活力。 可溶性的CF_1经用DTT或胰蛋白酶活化后所表现出的Ca~( )ATP酶活力对寡霉素敏感不同,DTT活化者受寡霉素的抑制,而胰蛋白酶活化者则不敏感。说明它的作用部位是在CF_1上而不在CF_0上,而且可能与胰蛋白酶活化时切去的多肽有关。 寡霉素对电子传递有一抑制作用部位,但其作用较轻微。     

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.     

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.     

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.     

Self-organization in the determination of the size of the axial structures in the embryogenesis of the clawed toad

Experiments were performed using X. laevis embryos during gastrulation and neurulation (stages 10, 11 1/2, 12 1/2, 13 1/2, 15 and 18). Part of presumptive epidermis and lateral plate mesoderm was removed, and embryos raised until stage 25. The size of axial structures (notochord, somite mesoderm, central nervous system) was determined using serial histological sections and compared with that of control embryos. In experimental embryos, the size of axial structures was decreased. Until a specific stage of development, close correlation was found between the volume of embryonic compartment corresponding to a particular, structure and the volume of presumptive epidermis and lateral plate mesoderm. This stage is individual for each axial organ: middle gastrula (stage 11 1/2) for notochord, late gastrula (stage 12 1/2) for somite mesoderm, and late neurula (stage 18) for central nervous system. This data suggest that differentiation pattern of ecto-mesodermal rudiment is subject to regulation during gastrulation-neurulation, and subdivision of ectoderm and mesoderm into axial and non-axial tissues is a self-organizing process.     

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.