独龙牛遗传多样性及其种群遗传结构的等位酶分析

用水平切片淀粉凝胶电泳技术, 进行30头独龙牛41种蛋白质共计44个遗传座位的等位酶分析,只在Tf、Hp、Amy、Est等4个座位发现多态性。每个座位等位基因的平均数、多态座位百分 比和平均杂合度值分别为A=1.0909、P=0.0682和H=0.0262。贡山县和福贡县独龙牛群体从酶基因的角度上看遗传多样性贫乏, 可能是分别由小种群引种而来, 受到瓶颈效应的作用, 并伴随着创立者事件的发生。表3参12

中国大白蚁亚科壤白蚁新属新种(等翅目:白蚁科)

壤白蚁属 Parahypotermes Zhu et Huang, 新属模式种: 曼允壤白蚁Parahy potermes manyunensis, 新种. 属征: 兵蚁头近卵圆形, 头背面被毛稀少, 两侧缘于触角前骤然狭缩, 头中部最宽, 后缘宽圆, 头背面中部明显隆起; 左上颚内缘中部第1缘齿上方具2—3枚小齿. 比较与讨论: 本新属与地白蚁属 Hypotermes Holmgren 较接近. 但 Hypotermes 头两侧缘触角前不呈狭缩状; 左上颚第1缘齿上方不具锯齿状小齿; 头背面中部呈弧状隆起。

RESERPINE IMPAIRS SPATIAL WORKING-MEMORY PERFORMANCE IN MONKEYS - REVERSAL BY THE ALPHA-2-ADRENERGIC AGONIST CLONIDINE

Repeated daily treatment with the catecholamine-depleting agent, reserpine, dramatically reduced performance on the delayed response task, a test of spatial working memory that depends upon the integrity of the prefrontal cortex. Delayed response performance fell from an average of 27.2/30 trials correct before reserpine treatment to an average of 20.4/30 trials correct after repeated reserpine administration. Injection of the alpha2-adrenergic agonist, clonidine (0.0001-0.05 mg/kg), to chronic reserpine-treated monkeys significantly restored performance on the delayed response task; performance after an optimal dose averaged 27.8/30 trials correct. Clonidine's beneficial effects on delayed response performance were longlasting; monkeys remained improved for more than 24 h after a single clonidine injection. The finding that clonidine is efficacious in reserpinized animals supports the hypothesis that alpha2-adrenergic agonists improve cognitive function through actions at postsynaptic, alpha2-adrenergic receptors on non-adrenergic cells. In contrast to the delayed response task, reserpine had little effect on performance of a visual discrimination task, a reference memory task which does not depend on the prefrontal cortex. These results emphasize the importance of postsynaptic alpha2-adrenergic mechanisms in the regulation of working memory,

High prevalence of HIV-1 and hepatitis C virus coinfection among injection drug users in the southeastern region of Yunnan, China

The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities, HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) (p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.