镉、铅对蟾蜍精巢毒作用的酶学研究

为研究镉、铅对精巢的生化毒作用机理 ,应用氯化镉、硝酸铅溶液对成年雄性蟾蜍进行腹腔染毒 (按镉计 0 .1、0 .2、0 .4、0 .8mg/ kg体重 ;按铅计 1、2、4、8mg/ kg体重 ) ,连续染毒 7d后活体解剖 ,测定分析精巢中各种酶的活性。结果显示 ,在镉染毒下 ,精巢乳酸脱氢酶 (L DH)和酸性磷酸酶 (ACP)的活性随镉染毒剂量的增加而降低 ,而碱性磷酸酶 (AL P)未发现明显变化 ;在铅染毒下 ,乳酸脱氢酶 (L DH)和碱性磷酸酶 (AL P)的活性随铅染毒剂量的增加而降低 ,而酸性磷酸酶 (ACP)未发现明显变化 ;乳酸脱氢酶 (L DH)同工酶在镉、铅染毒下则主要表现为酶带 L DH1 、L DH2 的抑制或缺失和 L DH5活性的增强。因此 ,镉、铅对蟾蜍的雄性生殖毒性机理可能与酶的活性存在着一定的关系 ,L DH可以考虑作为反映镉、铅中毒对精巢功能影响程度的一种有价值的生化指标     

高效氯氰菊酯对中华蟾蜍蝌蚪的毒性影响

以中华蟾蜍蝌蚪为实验对象,采用半静态毒性试验方法研究了高效氯氰菊酯对其的急性毒性和生理毒性。结果表明:高效氯氰菊酯对中华蟾蜍蝌蚪的96h半致死浓度(96h-LC50)为1.147mg/L,其毒性为中级;蝌蚪的总抗氧化能力(T-AOC)随染毒时间的延长而逐渐降低,当高效氯氰菊酯质量浓度达到1μg/L以上时,蝌蚪的T-AOC在出现兴奋效应后随即下降;蝌蚪体内的谷胱甘肽-S转移酶(GSH-ST)活性随着农药浓度的增大和染毒时间的延长呈现出不断增加的趋势,当高效氯氰菊酯质量浓度达到1μg/L以上时,蝌蚪的GSH-ST活性较对照组有极显著的提高。研究表明,高效氯氰菊酯对中华蟾蜍蝌蚪会造成一定的毒性影响。     

阿维菌素对黑斑侧褶蛙毒理效应的研究

本文选用生物农药阿维菌素作为染毒试剂,以农田中常见黑斑侧褶蛙Pelophylax nigromaculatus为研究对象,分别从急性毒性、亚急性毒性、遗传毒性和生理毒性四个方面的实验综合探讨了阿维菌素对黑斑侧褶蛙的生态毒理学效应。急性毒性实验结果表明,阿维菌素对黑斑侧褶蛙24h、48h、72h、96h的LC50分别为:0.3227mg/L、0.0966mg/L、0.0623mg/L、0.0432mg/L,其对黑斑侧褶蛙的安全浓度(SC)为0.004316mg/L。亚急性毒性实验结果表明,暴露期间,随着浓度的升高,毒害作用越大,其对黑斑侧褶蛙肝脏组织损害也越大,而经恢复期后,各实验组肝脏组织受损程度较暴露期都有降低。红细胞核异常及微核诱导实验结果表明,微核和核异常现象与阿维菌素浓度的相关性有一定的范围;随着时间的延长,红细胞核异常率及微核率先上升后下降。肝脏LDH同工酶聚丙烯酰胺凝胶电泳实验结果表明,在一定时间条件下,随浓度的升高,LDH1和LDH2酶带活性呈现降低趋势,LDH4酶带活性无明显变化,LDH5酶带活性先升高后再降低,在同一浓度条件下,随着时间的延长,肝脏LDH同工酶活性均呈升高的趋势。实验结果表明阿维菌素对黑斑侧褶蛙能够造成不同程度的生理、病理及遗传性损伤。     

卡麦角林对黄毛鼠睾丸组织结构及四种标志酶活力的影响

为探讨卡麦角林剂量和处理后时间对雄性黄毛鼠睾丸组织结构和相关酶活力的影响,以50μg/kg和100mg/kg卡麦角林连续3d灌胃雄鼠,在处理后第7d和24 d镜检睾丸组织并分析组织中酸性磷酸酶（Acid phosphatase,ACP）、碱性磷酸酶（Alkaline phosphatase,AKP）、乳酸脱氢酶（Lactate dehydrogenase,LDH）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GSH-Px）的活力。结果发现：卡麦角林可使曲细精管内生精细胞、间质细胞和支持细胞受损,脱落解体。100µg/kg卡麦角林可降低ACP酶活力,处理后24 d时恢复;处理后AKP酶与对照无显著差异。处理组LDH酶活力显著增加,但剂量增加导致LDH活力增加幅度下降,且处理后24 d时恢复。100 µg/kg卡麦角林处理后24 d 时,GSH-Px酶活力显著高于对照组,且高于同浓度处理组第7d时的酶活力。处理后相同时间检测的GSH-Px活力高于50µg/kg处理组。结果表明卡麦角林对雄鼠生殖系统有一定的影响,可明显影响睾丸标志酶的活力。     

青霉酸对尼西鸡的毒性作用

采用人工染毒的方法,观察或检测了青霉酸（penicillic acid）中毒60d内尼西鸡的病理组织变化、血液生理生化指标、血清酶活性和青霉酸在脏器中的残留量。结果表明：（1）青霉酸中毒尼西鸡的主要病理变化是肝细胞脂肪变性、肾小管上皮细胞浊肿、心肌细胞颗粒变性;（2）红细胞平均压积（MCV）和红细胞平均血红蛋白浓度（MCHC）显著低于对照组;而谷丙转氨酶（SGPT）、乳酸脱氢酶（LDH）和碱性磷酸酶（AKP）等血清酶活性显著高于对照组;（3）青霉酸在各脏器中含量分布依次为肝＞肾＞心,表明青霉酸的分布与各脏器的病变程度具有相关性,肝脏是青霉酸作用的靶器官。其结果为家禽青霉酸中毒疾病的防治和青霉酸的中毒机理提供了科学依据。     

铅对鲫鱼碱性磷酸酶和酸性磷酸酶活性的影响

在实验条件下,将鲫鱼置于1、10、40 mg/L的Pb2 溶液中静态染毒,分别在24 h、48 h、96 h、144 h测定鳃、肝、胰、肾、脑组织的碱性磷酸酶(AKP)和酸性磷酸酶(ACP)活性.结果 表明,鲫鱼鳃、肝、胰、肾、脑组织中碱性磷酸酶和酸性磷酸酶的活性随着铅浓度的升高和染毒时间的延长均呈下降趋势,其中以肾脏和脑下降最明显.     

除草剂稻草隆对蝌蚪生长发育的影响

本文从形态学和红细胞核异常两方面观察了除草剂稻草隆对黑眶蟾蜍蝌蚪生长发育的影响. 结果表明,实验组与对照组间卵的最终出膜率差异不显著.在除草剂浓度分别为0,10,14,18,20 mg/L时,蝌蚪存活率从高到低顺序为：96.7%〉86.7%〉76.7%〉53.3%〉33.3%.经浓度为2,8,10,15 mg/L的除草剂溶液处理后,发现除草剂溶液对蝌蚪体长、体重有显著性影响（P＜0.05）,而引起的红细胞核异常率随浓度增加而升高.     

复合肥对花背蟾蜍蝌蚪红细胞微核及核异常的影响

以花背蟾蜍蝌蚪外周血红细胞微核及核异常作为毒理监测指标,对Gosner 31、42和46期蝌蚪进行观察,研究了复合肥对水生生物的毒性效应.结果表明:用复合肥溶液浓度为1、1.5、2、2.5和3g·L-1进行染毒时,红细胞出现了大、小2种类型的微核,在核异常类型中出现了严重的核分叶和双核类型;在3个被观察的蝌蚪发育期中,42期蝌蚪红细胞微核细胞率和核异常细胞率数值明显低于其他两个发育期;在5个浓度的染毒中,2.5g·L-1浓度组在微核、双核和核分叶与对照组间无显著性差异;花背蟾蜍不同发育时期的蝌蚪,对生境中不良因素的抵抗能力存在着明显的差别,且微核和核异常与复合肥浓度之间没有明显的剂量-效应关系.     

重金属铅对鲫鱼乳酸脱氢酶和过氧化氢酶活性的影响

在实验室条件下,采用毒性实验方法研究不同浓度重金属铅(Pb2 )对鲫鱼血清乳酸脱氢酶(LDH)和血液过氧化氢酶(CAT)活性的影响.研究结果表明,随着金属离子铅浓度的增高血清中乳酸脱氢酶和过氧化氢酶活性下降,但两种酶对铅离子影响的敏感程度不同.影响LDH活性的最低铅离子浓度为0.1mmol/L,而CAT为0.5mmol/L,当Pb2 浓度为1mmol/L时,LDH活性降至10%左右,而CAT仅下降50%左右.对重金属离子浓度与酶活性的定性和定量分析为有效监控鱼类生存环境提供了有价值的参考资料.     

重金属镉对鲫鱼碱性磷酸酶和酸性磷酸酶活性的影响

研究了重金属镉对鲫鱼肠、肝胰脏、鳃组织碱性磷酸酶和酸性磷酸酶活性的影响。结果表明,在0.2、0.4、0.8mg/L镉浓度条件下静态染毒12h、24h、48h、96h后,鲫鱼肠、鳃组织中碱性磷酸酶(AKP)和酸性磷酸酶(ACP)的活性降低,肝和胰脏的碱性磷酸酶活性没有明显变化,其酸性磷酸酶活性则升高。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.