大头鲤原种种群的遗传现状

大头鲤(Cyprinus pellegrini)是一种云南高原湖泊特有的国家Ⅱ级重点保护鱼类.土著种大头鲤与外来种鲤(C.carpio)的渐渗杂交在星云湖野生种群中已经广泛发生.本研究结合形态和微卫星及线粒体DNA分析检测了螺蛳铺大头鲤原种种群的遗传现状.结果显示,螺蛳铺大头鲤样本所有个体在形态上位于大头鲤与鲤的参照样本之间;在微卫星因子对应分析中也显示,其位于大头鲤与鲤的参照样本之间,但与大头鲤参照样本较为相似;在线粒体DNA分析中显示,都具有鲤的单倍型.中间性形态特征以及核基因组成与线粒体基因组成的不一致现象,表明螺蛳铺大头鲤样本均为杂种个体.因此,螺蛳铺大头鲤原种种群可能是一个杂种种群,有必要重新建立大头鲤人工繁殖计划.     

热休克法抑制第一次卵裂实现草鱼雌核发育的细胞学观察

用组织切片方法系统地观察了草鱼卵被经辐射处理的鲤精子激活后进行第一次卵裂的发育过程。实验表明：在24℃孵化水温下草鱼卵在被激活后24min进入第一次卵裂胶期,27－30min处于中期,33min进入后期。由此可知被激活的草鱼卵子在第24min时已经完成染色体的复制,使草鱼卵子雌核染色体人工加倍的最佳时期是在被激活后的27－30min这一时间区段内。此外,用不同热休克温度和不同的热休克强度处理已完成染色体复制的被激活草鱼卵,表明草鱼卵经41℃处理2min可得到较高比例的基因纯合型雌核发育二倍体鱼。     

鲤鳃表面结构扫描电镜研究

鲤的鳃丝表面显示了由三边形一六边形不等的表皮细胞,呈现出各种图案式的结构。     

鲤肠道正常菌群的研究

本实验用稀释滴种的定量方法,对淡水养殖地中健康鲤肠道内的１０种菌群进行了定性、定量分析,并对结果进行统计学处理,得到鲤肠菌群的一些生理值。结果表明鲤肠道中需氧、兼性厌氧优势菌是气单胞菌和酵母菌,厌氧优势菌是拟杆菌。对不同时间、不同温度条件下同一养殖池中鲤肠道菌群的测定结果比较表明：葡萄球菌、假单胞菌差异显著（ｐ＜０．０５）,气单胞菌、大肠杆菌、需氧芽胞杆菌、酵母菌、乳酸杆菌、双歧杆菌、拟杆菌、梭状芽胞杆菌差异不显著（ｐ＞０．０５）,表明该８种菌群在鲤肠道中的菌数处于相对稳定状态,属于肠道正常菌群。     

Effect of tributyltin on adenylate content and enzyme activities of teleost sperm: a biochemical approach to study the mechanisms of toxicant reduced spermatozoa motility

The effects of tributyltin (TBT) on the energy metabolism and motility of fish spermatozoa were investigated in vitro in African catfish and common carp. A significant (P<0.05) decrease of the duration and the intensity of motility was observed in catfish spermatozoa exposed to 0.27 microg/l TBT for 24 h. Exposure of catfish spermatozoa to 2.7-27 microg/l TBT caused an instant decrease in ATP content. In the presence of 27 microg/l TBT approximately 55% of the initial ATP concentration in catfish semen was lost after 60 min incubation while AMP concentrations increased and the total adenine nucleotide (TAN) pool remained unchanged. The reduction in sperm ATP levels could not be attributed to cell death since viability decreased only slightly over the period of exposure. In carp by contrast, none of the adenylates concentrations studied (ATP, ADP and AMP) were affected by TBT exposure at any experimental condition. However, carp sperm motility was significantly reduced by exposure to 2.7 microg/l TBT. Among the enzymes investigated only lactate dehydrogenase (LDH) in catfish sperm was significantly (P<0.01) affected by 27 microg/l TBT treatment with a reduction in activity of approximately 75%. Compared with carp sperm before TBT exposure, that of catfish had lower adenylate contents and overall lower enzymatic activities; this explains its slower sperm velocity and shorter duration of movement as measured by computer assisted sperm analysis (CASA). The present in vitro study shows that catfish spermatozoa are more sensitive to TBT exposure (and probably to other toxicants) than those of carp.     

草鱼CNBP的分子特征及其进化分析

从草鱼(Ctenopharyngodon idella)肝肾cDNA文库中克隆到细胞核酸结合蛋白基因CNBP的完整开放阅读框序列.分析表明草鱼CNBP由163个氨基酸残基组成,含有7个保守CCHC型锌指结构、核定位信号区和RGG框,与其他鱼类的同源性很高.与人及其他脊椎动物的相比,草鱼细胞核酸结合蛋白在第3个锌指中的第5个氨基酸残基由Gly变成His,另外在第1锌指和第2锌指结构间,缺失6～14个氨基酸残基.虽然如此,适应性进化分析显示细胞核酸结合蛋白没有经历正达尔文选择(ω≤1),即这种结构的差异还不足以产生新的功能.这表明CNBP处于中性进化中.     

Temperature acclimation of gross cardiovascular morphology in common carp (Cyprinus carpio)

Temperature is of fundamental importance in the functioning of the cardiovascular system of ectothermic fish, with cold-induced ventricular hypertrophy and increased red muscle mass being reported in a number of fish species upon cold acclimation. This study demonstrates a non-linear cold-induced ventricular hypertrophy in common carp (relative ventricular mass (RVM)=0.086±0.003%, 0.074±0.005% and 0.074±0.004% at 5, 15 and 25 °C, respectively), but a cold-induced atrophy of the lateral red muscle mass (RMM) with respect to total muscle mass (2.504±0.554%, 3.982±0.818% and 4.490±0.256% at 5, 15 and 25 °C, respectively). The ventricular hypertrophy in carp acclimated to 5 °C reflects a compensation against the increased workload of pumping viscous blood at low temperatures and the negative inotropic effects of the cold, whereas atrophy of the red muscle is likely due to disuse resulting from reduced locomotory activity in the cold.