【作者】 刘长水；

【导师】 张士璀；

【作者基本信息】 中国海洋大学 ， 海洋生物学， 2010， 硕士

【摘要】 贡氏假鳃鳉是一年生季节性鱼类,由于在野外环境中长期受季风性气候的影响,形成了遗传性的短暂的生命周期。在旱季到来前,它们将卵产在水底的泥土中；等到雨季来临时,小鱼快速孵化,长大,产卵后急速衰老,并且这些性状的表达对温度的变化极为敏感。因此,本论文的研究目的就是对不同温度下饲养的贡氏假鳃鳉的生长、发育、性成熟及衰老等几个方面展开研究,以证明温度这一外部因素所起到的重要的影响作用。研究方法简述如下,将同日孵化的贡氏假鳃鳉饲养于4个不同温度的容器中,温度分别设置为25℃、27℃、29℃、31℃。每日观察4个温度组中贡氏假鳃鳉的生长发育和存活状况,每周进行一次相关数据的测量记录工作,并按月份汇总,绘制曲线。在贡氏假鳃鳉7月龄时,使用体格强健的雄鱼为代表展开各温度组的衰老研究工作,衰老检测选用以下四类衰老标记物：上皮组织中的SA-β-Gal(衰老特异性β—半乳糖苷酶),骨骼肌中蛋白的氧化水平,肝脏中的脂褐素,大脑皮层的神经退行性变。最终比较各温度组衰老标记物量的差别以揭示机体的衰老情况。结果表明,温度对贡氏假鳃鳉的影响显著,并且较低的温度更适于贡氏假鳃鳉的生存。其中,25℃、27℃、29℃、31℃四个温度组中,25℃表现出最良好的生长发育和成熟状况,存活数量最多,并且衰老程度相比其他温度组最轻。相比于25℃组,随着温度的增高,贡氏假鳃鳉的生长和发育情况会出现下降的趋势,其中29℃、31℃两组下降最为显著。如生长会受到高温的抑制而有所减弱；脊椎在29℃、31℃两组中出现了异常发育的现象。此外,将雄鱼和雌鱼的性成熟和存活状况比较后发现,雌鱼受到温度变化的影响更为明显。如低温下,雌鱼的首次排卵期会比高温组提前1-2周到来,而雄鱼发色期较为稳定,早晚未发生显著改变；并且雌鱼在低温下更易存活,致使雄鱼所占总数比例变化不大。上述四类衰老标记物的表达量,随着温度的降低也呈逐次下降趋势,说明低温下的贡氏假鳃鳉衰老程度较轻,即降低温度可以延缓贡氏假鳃鳉的衰老进程。综上得知,贡氏假鳃鳉的生长、发育、成熟、存活数和衰老等方面都对温度的变化十分敏感,并且较低的温度对贡氏假鳃鳉的生存具有积极显著的影响。更多还原

【Abstract】 As a annual killifish, Nothobranchius guentheri (N. guentheri) has a genetic short lifespan which results from the constant monsoon climate in their original habitat. N. guentheri originates from savannah regions in East Africa and has adapted to the seasonal changes between heavy rains and severe draught. They are egg-layers and deposit their eggs in the mud during the dry season, and the eggs will continue to develop and hatch when the rainy season begins. After hatched out, the fish will rapidly grow up, mate and become aging in months. And their living and aging is sensitive to the change of ambient temperature. Therefore, the aim of our research is to study the effects of different temperatures on the growth, development, sexual maturation and aging of N. guentheri.Research methods are stated briefly as follows. An equal number of N.guentheri fry are raised separately under the four temperatures 25℃,27℃,29℃and 31℃dating from their birth. Daily observation and record are taken on their development and survival, and weekly measures are carried on the variation of their body length and egg number. Then summary is done once a month and curves based on the results will be drawn. Moreover, aging research is commenced on the strongest male fish at the age of seven months old in the four temperature groups. And four aging markers are selected and utilized below:SA-β-Gal in the epithelium, lipofuscin in the liver, protein oxidation in the muscle and neurodegeneration in the brain. The amount of the four markers are compared to show the overall aging of organism.The conclusion illustrated that the effects of temperature were prominent on N.guentheri, which showed a better growing and living at lower temperature. Especially, the fish in the 25℃group presented the best situation of growth, development, maturation and surviving among all the four groups. And they were getting aging more slowly.Compared with the 25℃group, higher temperatures bated the growth, and the backbones of the fish developed a unnormal bending in the groups of 29℃and 31℃.Furthermore, it has been found that the female were influenced more obviously than the male by the change of temperature. At lower temperatures, the first spawn appeared over one weeks earlier than that at higher temperatures, while the time had hardly differed when the male of 4 groups turn colorful. Also, low temperature could keep the population of the female steady as well as the male.Besides, quantification of the four aging markers also demonstrateed that at lower temperatures, expression of the 4 aging markers stated above were reduced compared with those at higher temperatures. That means low temperature can slow and defer the process of aging in N.guentheri.In summary, N.guentheri is sensitive to the change of temperature on the aspects of growth, development, sexual maturation, survival and senescence, and low temperature has apositive and distinct effects on their lives.更多还原