不同光照周期对脊尾白虾生长、性腺发育以及血淋巴生化成分的影响

为探讨不同光照周期对脊尾白虾(Exopalaemon carinicauda)生长、性腺发育以及血淋巴生化成分的影响,本研究挑选体质量为(0.71±0.05) g、体长为(3.62±0.28) cm的脊尾白虾,在水温23~25℃、盐度22~24、pH 7.8~8.1、光照强度为1000 lx的养殖条件下,测定其在5种光照周期(全光照L、16L︰8D、12L︰12D、8L︰16D、全黑暗D,L表示光照时长,D表示黑暗时长)下的生长、性腺发育以及血淋巴生化成分等相关指标。结果显示,在存活率方面,全黑暗组最高[(86.67±5.77)%],其次为12L︰12D组[(83.33±8.82)%],再次为8L︰16D组[(80.00±3.33)%],3组之间无显著差异(P>0.05);在特定生长率方面,8L︰16D组的特定生长率为(2.49±0.20)%/d,显著高于全黑暗组(P<0.05);在蜕壳率方面,8L︰16D组蜕壳率最高,为(6.96±0.50)次/(尾·d)。性腺指数随光照时间的缩短逐渐增大,在光照时间为8L时达到最高值[(2.37±0.04)%],显著高于其他组(P<0.05);8L︰16D组卵巢成熟率为(42.93±4.57)%,显著高于全黑暗组(P<0.05);8L︰16D组卵巢相对长度在实验第30天时显著高于其他组(P<0.05)。8L︰16D组血淋巴蛋白质和胆固醇浓度显著高于全光照组、16L︰8D组和全黑暗组(P<0.05),与12L︰12D组无显著差异(P>0.05);8L︰16D组葡萄糖浓度显著高于全光照组和全黑暗组(P<0.05),与16L︰8D组和12L︰12D组差异不显著(P>0.05);8L︰16D组甘油三酯浓度显著高于其他组(P<0.05)。研究表明,不同光照周期对脊尾白虾生长、性腺发育以及血淋巴生化成分均产生不同程度的影响,8L︰16D是脊尾白虾亲虾促熟和工厂化养殖较为适宜的光照周期。     

Reproductive biology of freshwater fishes from the Venezuelan floodplains

This review describes the endocrine changes that occur during the annual reproductive cycle of Pygocentrus cariba, Pimelodus blochii, and Oxydoras sifontesi and their relationships with the environmental characteristics of Venezuelan floodplains. Most reproductive studies of teleosts have focused on changes that occur during annual cycles in temperate species but, in tropical fish, this has been examined less frequently. P. cariba, P. blochii, and O. sifontesi are seasonal breeders widely distributed along the Orinoco River. Under natural conditions they have an annual gonadal cycle closely related to changes in the annual hydrology cycle of the Orinoco River which defines two seasons on the floodplain: inundation and isolation. The reproductive cycle of these species seems to be controlled by cues from the external environment. Relevant data about gonadal maturation, for example gonadosomatic index and sexual hormones secretion, are contrasted. The role of catecholamines in neuroendocrine control of the reproductive axis is also considered in this work.     

海鳗性腺形态和发育的研究

本文对海鳗性腺的形态与组织结构及发育周年变化进行了研究。海鳗卵巢由许多紧密排列的卵巢叶片构成,精巢则由许多精巢叶片构成。整条卵巢或精巢的外部无被膜包裹。组织学表明,卵巢在５月下旬后陆续发育成熟,精巢在４月正旬陆续发育成熟。５月下旬进入繁殖期,６月－７月为繁殖盛期。随后产过卵的个体进入恢复期并重新发育。组织学与扫描电镜观察显示,海鳗的精子头部呈镰刀形,有一定较短的尾部     

三氯生对黄河鲤幼鱼性腺发育分化相关基因表达的影响

为了探讨三氯生（TCS）对黄河鲤(Cyprinus carpio)幼鱼性腺分化的分子机制,采用半静态水体暴露法,将体长为7.8～9.9 cm的黄河鲤幼鱼暴露于0（对照）、0.04、0.08、0.16 mg/L的三氯生溶液中42 d,利用RT-qPCR技术检测黄河鲤性腺发育分化相关基因表达情况。结果显示,雄鱼精巢中,dax1和sox9a基因在0.04 mg/L和0.08 mg/L TCS处理组中均极显著上升（P<0.01）,0.08 mg/L处理组中sox9b、dmrt1和foxl2基因显著或极显著上升（P<0.01,P<0.05,P<0.01）,nobox基因在0.04 mg/L和0.16 mg/L TCS处理组显著和极显著下降（P<0.05,P<0.01）,zp2基因在各TCS处理组显著或极显著上升（P<0.05,P<0.01）,ar和amh基因在各TCS处理组显著和极显著下降（P<0.05,P<0.01）;雌鱼卵巢中,sox9b基因在0.04 mg/L和0.08 mg/L TCS处理组均极显著上升（P<0.01）,s...     

Molecular mechanisms of sex determination and gonadal sex differentiation in fish

We have used various genetic and molecular approaches to investigate the mechanisms of sex determination and gonadal sex differentiation in fish. DMY was identified as the sex-determining gene of medaka. In tilapia, endogenous estrogens act as natural inducers of ovarian differentiation, while DMRT1 may be important for testicular differentiation. The roles of these regulators in sex determination and gonadal sex differentiation were ascertained using a gene or hormonal blockade strategy.     

A comparison of growth and biochemical composition of <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> (Lmk.) and <Emphasis Type="Italic">Mytilus edulis</Emphasis> (L.) on the West coast of Cotentin,Normandy, France 1999–2000

The blue mussel, Mytilus edulis has been reared along the Normandy coast line since the 1960s. The gonadal cycle of this mussel species shows a sharp decrease in meat quality during the winter period after spawning. This decline in meat quality is so severe that sales have to be suspended from December to July. Another species of mussel, Mytilus galloprovincialis, which is reared in the lagoons along the French shore of the Mediterranean Sea has a different spawning cycle. An experiment was undertaken to study the meat quality of M. Galloprovincialis throughout the year after the spat were transferred from the Mediterranean Sea to the Normandy coast. This species showed an immediate adaptation to the gonadal cycle of M. edulis. Despite suggestions from researchers, no interest was expressed to consider such transfers of M. galloprovincialis in the future.     

维甲酸X受体在杂色鲍性腺发育中的调控作用研究

[目的]研究维甲酸X受体在杂色鲍性腺发育中的调控作用。[方法]采用实时定量PCR技术和RNA干扰技术,分析RXR基因在杂色鲍性腺发育过程中的表达情况。[结果]RXR基因在性腺发育增殖期的不同组织的表达量与其他发育时期相比均存在显著差异,这表明增殖期是RXR在杂色鲍性腺分化与发育发挥作用的窗口期。注射dsRXR后,dsRXR注射组维甲酸X受体在卵巢中的表达量与绿色荧光阴性对照组和空白对照组相比显著下调。这些结果证实了对杂色鲍进行活体注射双链RNA可以让体内的目的基因产生基因沉默现象。[结论]RXR基因在杂色鲍性腺发育过程中起到关键作用,并且增殖期为RXR发挥作用的窗口期。     

The Relative Position of the Penis in Southern African Dassies (Hydracoidea) as a Character of Taxonomic Importance

Histological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to thatof freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus undergoes seasonal gross morphological and cytological gonadal changes with previtellogenesis dominating during the winter, vitellogenicdevelopment during spring and summer culminating in large-scale spawning at the end of summer. Post-spawning mass atresiaofoocytes was evident in autumn. The histological data presented support macroscopical evidence that L. cylindricus is a synchronous iteroparous spawner, reproducing over a short period each year throughout its life-span.     

杂色角孔海胆形态学观察、亲缘关系及性腺营养成分分析

本研究以杂色角孔海胆(Salmacis sphaeroides variegate)为研究材料,观察其形态,基于线粒体16S rDNA基因部分序列分析杂色角孔海胆与其他棘皮动物的亲缘关系,同时分析杂色角孔海胆性腺中的营养成分,为杂色角孔海胆种质改良和资源评估积累数据。结果显示,杂色角孔海胆的主要形态特征具有口器较小,每个步带板的外缘有3~4个小的圆形凹孔,管足壁内的骨片为C形。通过Mega 5.0对其他棘皮动物和得到的杂色角孔海胆的线粒体16S rDNA基因部分序列进行比较,基于距离法(NJ)和最大似然法(MP)分别构建系统树。结果显示,杂色角孔海胆与疏棘角孔海胆(Salmacis bicolor rarispina)的亲缘关系最近,其次是刻肋海胆属的3种海胆;杂色角孔海胆性腺中水分为86.1%,灰分为3.0%,粗脂肪为2.0%,蛋白质为8.01%;杂色角孔海胆性腺中的氨基酸种类共有16种,总含量为38.71 g/100 g,EAA/TAA为36.99%,EAA/NEAA为71.84%,DAA/TAA为37.17%;脂肪酸共检测到15种,含量最高的是棕榈酸C16:0、硬脂酸C18:0、EPA C20:5和花生四烯酸C20:4,含量最低的为二高-γ-亚麻酸C20:3,较其他海胆,其DHA含量较高。研究结果将为杂色角孔海胆的生物学研究提供基本资料,可用于经济海胆开发应用,同时也可为远缘杂交育种及经济海胆的种质鉴定提供理论依据。