家养动物的起源与驯化研究进展

一_二部分则涉及家养动物驯化的条件、过程、性状改变及其遗传机制等方面.最后指出了家养动物起源与驯化研究中依然存在的问题,并对未来研究发展的趋势进行了讨论.

猪线粒体DNA多态性与中国地方猪种起源分化的关系

用24种限制性内切酶分析了我国21个具代表性地方猪品种、1个引进品种和2个来自中国和越南的野生近缘种mtDNA的RFLP。结果表明:在74个个体中检出的32种限制性态型可归结成7种单倍型,其间的差异主要来源于少数几个限制性位点的点突变;地方猪种4种单倍型间的平均遗传距离为0.143％,遗传多态程度(π值)仅为0.007％,说明遗传多样性非常贫乏,提示中国地方猪种可能起源于一个野猪亚种。

不同渗透压的稀释液对猕猴精子低温冷冻保存的影响

以稀释液TTE (382 mOsm/ kg) 为对照, 研究了5 种渗透压(688 、389 、329 、166 、43 mOsm/ kg) 的TEST 稀释液(TEST、mTEST1、mTEST2、mTEST3、mTEST4) 在冷冻过程中对猕猴精子功能的影响。精液一 步稀释于含甘油的防冻液中, 甘油的终浓度为5 % (v/ v) 。在冷冻前后分别检测精子的运动度和质膜完整性, 后者用Hoechst 33342 和碘化丙锭双色标记流式细胞术分析。结果表明: 冷冻之前, 与鲜精相比, 用TEST 和 mTEST4 稀释的精子运动度和质膜完整性显著降低( P < 01001) , 其余组中除mTEST2 稀释的精子质膜完整性显 著降低( P < 0105) 外, 精子运动度无差异; 冷冻复苏后, TTE、mTEST3 和mTEST1 冻存精子的运动度和质膜 完整性最高, 其次是mTEST2 , TEST和mTEST4 冷冻效果最差( P < 0105) 。提示等渗、适当高渗或低渗的稀释 液适合猕猴精子的冷冻保存; 对精子产生高渗毒害作用是导致猕猴精子用TEST 冷冻存活率低的主要原因。

云南滇池濒危特有种滇池金线鲃人工繁殖初报

滇池金线鲃(Sinocyclocheilus grahami)是滇池湖泊生态系统的指示物种和特有种.因水质污染和外来物种入侵等因素的影响,该鱼类自1986年起就从湖体中消失,仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃.至2007年3月初,有两次繁殖试验取得了成功.先后试验了5尾雌鱼和6尾雄鱼,获得鱼卵约1 600粒,并实施干法受精.约有1 320粒受精,平均受精率为73%.孵化出鱼苗约480尾,平均孵化率为36%.经10天饲养,约有95%以上的鱼苗存活,体长达8-12 mm.滇池金线鲃人工繁殖成功的意义有三点:能有效保护该物种免于灭绝;繁殖的鱼苗放归湖泊合适水域,将有助于恢复滇池的土著生物多样性;有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变.

Structural and functional characterization of the human CCR5 receptor in complex with HIV gp120 envelope glycoprotein and CD4 receptor by molecular modeling studies

The entry of human immunodeficiency virus (HIV) into cells depends on a sequential interaction of the gp120 envelope glycoprotein with the cellular receptors CD4 and members of the chemokine receptor family. The CC chemokine receptor CCR5 is such a receptor for several chemokines and a major coreceptor for the entry of R5 HIV type-1 (HIV-1) into cells. Although many studies focus on the interaction of CCR5 with HIV-1, the corresponding interaction sites in CCR5 and gp120 have not been matched. Here we used an approach combining protein structure modeling, docking and molecular dynamics simulation to build a series of structural models of the CCR5 in complexes with gp120 and CD4. Interactions such as hydrogen bonds, salt bridges and van der Waals contacts between CCR5 and gp120 were investigated. Three snapshots of CCR5-gp120-CD4 models revealed that the initial interactions of CCR5 with gp120 are involved in the negatively charged N-terminus (Nt) region of CCR5 and positively charged bridging sheet region of gp120. Further interactions occurred between extracellular loop2 (ECL2) of CCR5 and the base of V3 loop regions of gp120. These interactions may induce the conformational changes in gp120 and lead to the final entry of HIV into the cell. These results not only strongly support the two-step gp120-CCR5 binding mechanism, but also rationalize extensive biological data about the role of CCR5 in HIV-1 gp120 binding and entry, and may guide efforts to design novel inhibitors.

Disconnection of the hippocampal-prefrontal cortical circuits impairs spatial working memory performance in rats

There is a unidirectional, ipsilateral and monosynaptic projection from the hippocampus to the prefrontal cortex. The cognitive function of hippocampal-prefrontal cortical circuit is not well established. In this paper, we use muscimol treated rats to inv