鲫鱼肠道温和气单胞菌的分离鉴定及药敏试验

从鲫鱼肠道分离纯化获得一株细菌,编号为XA-2,对其进行形态观察,并对理化特性、16S rDNA克隆测序及系统发育进化树构建等研究．结果表明,XA-2菌株为革兰氏阴性短杆菌,可发酵葡萄糖产气;进一步采用 PCR方法克隆16S rDNA序列,测得长度为1508 bp ;对系统发育进化树分析,发现XA-2菌株与温和气单胞菌（Aero-monas sobria）模式菌株NCIMB 12065的亲缘关系最近,同源性达99.73％,从而鉴定XA-2菌株为温和气单胞菌．采用27种抗生素进行药敏试验,结果显示该菌株对头孢噻吩、头孢噻肟、头孢克肟、头孢哌酮、新霉素、诺氟沙星、复方新诺明等药物敏感,对先锋霉素Ⅳ、阿莫西林、庆大霉素、卡那霉素、红霉素等药物不敏感．     

异育银鲫对糖利用性的研究──饲料糖含量对生长、消化吸收率及体成分的影响

用糊精含量分别为５％、２５％、５０％的三种饲料饲养异育银鲫,研究异育银鲫对糖利用性特点,每个循环过滤水族箱中放养４０尾鱼,每种饲料喂两箱之鱼,饲养六周．摄食不同饲料的异育银鲫增重率有显著差异（ｐ＜０．１）,２５％糊精组生长最快,５％糊精组生长最慢．异育银鲫对三种饲料中糖的消化吸收率随着饲料糖含量的增加而极显著提高（ｐ＜ ０．０１）,粗蛋白的消化吸收率虽然各组间差异不显著,但也有相同的趋势．摄自不同糖含量饲料的鱼其肌肉含水量随饲料糖含量增加明显下降（ｐ＜０．０５）,粗蛋白和脂肪的含量随饲料糖含量的增加而增加,但差异不显著．在禁食２４小时时,肝糖元含量随饲料糖含量增加而显著提高,但能降解肝糖元的肝脏淀粉酶活性差异不显著（ｐ＜０．０５）．     

实验红鲫对137Cs 辐射的氧化应激响应

摘要: 目的探讨实验红鲫对137 Cs 辐射的氧化应激响应和氧化应激生物标记物。方法实验红鲫分别以0 Gy、1. 94 Gy、3. 88 Gy、7. 76 Gy、15. 53 Gy137Cs 辐照,分别于24 h,48 h,72 h,96 h 取出肝脏、性腺,按试剂盒方法检测SOD、GSH-PX 活性,于7 d 和14 d 取出肝脏、肾脏、心脏、脑,按Western blot 方法检测HSP70 含量。结果1. 94 Gy至15. 53 Gy137Cs 辐照能引起实验红鲫氧化应激,SOD、GSH-PX 活性和HSP70 含量发生改变。1. 94 Gy137Cs 辐照诱导实验红鲫肝脏SOD 活性升高, 3. 88 Gy、7. 76 Gy、15. 53 Gy137Cs 辐照诱导实验红鲫肝脏SOD 活性下降,且随辐射剂量升高,其SOD 活性逐渐降低。1. 94 Gy 以上137Cs 辐照诱导实验红鲫性腺SOD 活性下降,并随辐射剂量升高和时间的延长而下降,且下降幅度较大。各辐照处理组实验红鲫肝脏和性腺的GSH-PX 活性变化不大,表现出随辐射剂量升高则活性降低的变化趋势。137Cs 辐照处理后7 d 和14 d,各辐照处理组实验红鲫肝脏、肾脏、心脏和脑的HSP70 表达量均比对照组的高,且随着137Cs 辐照剂量的增加和时间的延长而升高,均存在着一定的“剂量－ 时间－效应”关系。结论实验红鲫性腺对137Cs 辐射的氧化应激响应较敏感,性腺SOD 和肝脏或肾脏的HSP70 可作为氧化应激标志物。     

Rapid growth and sterility of growth hormone gene transgenic triploid carp

Triploid carp (100%) with 150 (3n=150) chromosomes were obtained by crossing the females of improved tetraploid hybrids (♀, 4n=200) of red crucian carp (♀)×common carp (♂) with the males of diploid yellow river carp (♂, 2n=100). The crosses yielded transgenic triploid carp (positive triploid fish, 44.2% of the progeny) and non-transgenic triploid carp (negative triploid fish). Histological examination of the gonads of 24-month-old positive triploid fish suggested they were sterile and the fish were not able to produce mature gametes during the breeding season. Morphologically, both the positive and negative triploid fish were similar. They had a spindle-shaped, laterally compressed, steel grey body with two pairs of barbells. Most of the quantifiable traits of the triploid carp were intermediate between those of the two parents. The positive and negative triploid fish were raised in the same pond for 2 years. The mean body weight of the positive triploid fish was 2.3 times higher than the negative triploid fish. The weight of the largest positive triploid fish was 2.91 times higher than that of the largest negative triploid fish. Thus, we produced fast-growing transgenic triploid carp that have a reduced ecological risk because of their inability to mate and produce progeny.     

A new type of triploid crucian crap?red crucian carp (♀)×allotetraploid (♂)

A new type of triploid hybrids (TC) was produced by crossing red crucian carp (♀) with allotetraploid hybrids (♂). This type of triploids with no barbel was spindle-shaped and gray in color. Compared with their parents, some data of the morphological traits in the triploid hybrids were intermediate to those of their parents, and some were beyond their parents with heterozygous traits. Under the same culture conditions, the growth rate of the new type triploids was faster than their maternal red crucian carp (RC). The gonadal development of triploids was obviously slower than that of diploids, and the germ cells in them were degenerated. Compared with another type of triploids produced by Japanese crucian carp (♀) with allotetraploid hybrids (♂), the new type triploids not only kept faster growth rate and sterility, but also had no barbel that was similar to the common carp. The absence of the barbel in the new type of triploids has the important significance in both the inheritance and fish breeding.     

复合四倍体彭泽鲫雌核发育生殖方式的 胚胎同工酶证据

复合四倍体彭泽鲫是在尖鳍鲤精子刺激的彭泽鲫雌核发育子代中发现的少数特殊个体．本文分别用母本种彭泽鲫和父本种尖鳍鲤的精子与复合四倍体彭泽鲫的卵子受精，得到两种胚胎FP和FS．采用聚丙烯酰胺凝胶垂直板电泳技术对两种胚胎10个时期的5种同工酶（LDH、MDH、ME、SOD和EST）进行比较分析．结果表明:两种胚胎的5种同工酶表型在谱带上完全一致，不同来源的精子对胚胎的同工酶表型没有影响．表明复合四倍体彭泽鲫可能继承了母本种的雌核发育生殖方式．     

改进的遗传算法在球面点分布问题中的应用

球面点的分布问题,是世界性数学难题.对基本遗传算法进行了改进.采用实数编码,同时在遗传算法中引入了正交算子、变维子空间算子、灾变算子等高效演化算子,形成了自适应遗传算法.这样改进的算法极大地促进了个体多样性,并能促进优秀基因型的杂交和遗传,在收敛和鲁棒性方面优于一般的遗传算法,将它应用于球面点分布问题取得了较好的效果.