Leptocephalus larvae are the unique stage of larval development in all groups of fishes from the superorder Elopomorpha (Anguilliformes, Elopiformes and Notacanthiformes). To explain the leptocephalus strategy of larv...Leptocephalus larvae are the unique stage of larval development in all groups of fishes from the superorder Elopomorpha (Anguilliformes, Elopiformes and Notacanthiformes). To explain the leptocephalus strategy of larval development, various attempts have been made on the morphology, physiology and biochemistry of leptocephalus larvae. However, the feeding mechanism of leptocephalus larvae is still unknown. The Japanese eel (Anguilla japonica) larvae were found to have well developed scotopic vision, mechanoreception and chemoreception. Both early and leptocephalus larvae of Japanese eel actively ingested a kind of paste food by first touching the food with their snout and then tearing off a big mouthful of the paste with their sharp teeth. Chemoreception was shown to be critical to elicit the feeding response. Feeding by Sflex posture from a distance might be of some significance for the early larvae to catch movable food. It is proposed that that the natural food of Japanese eel larvae would be relatively large, rather soft, inactive and negatively phototactic. The developmental mode of sensory system and behavior of Japanese eel larvae seems to be similar to some deep sea fishes but contrast with most marine teleost fishes.展开更多
为初步阐明拟赤梢鱼(Pseudaspius leptocephalus)卵巢发育特征及sox3(sry related high mobility group box 3)基因在其卵巢发育过程中的作用,本研究通过组织切片观察了拟赤梢鱼卵巢早期发育过程,利用RACE技术克隆了该鱼sox3基因c DNA...为初步阐明拟赤梢鱼(Pseudaspius leptocephalus)卵巢发育特征及sox3(sry related high mobility group box 3)基因在其卵巢发育过程中的作用,本研究通过组织切片观察了拟赤梢鱼卵巢早期发育过程,利用RACE技术克隆了该鱼sox3基因c DNA全长序列,并进行生物信息学分析;利用实时荧光定量PCR技术分析了sox3基因在拟赤梢鱼不同组织及性腺不同发育时期的表达模式。结果显示,拟赤梢鱼卵巢在孵化后45 d分化形成,160 d时由Ⅰ期进入Ⅱ期,孵化后360 d,卵巢仍处于Ⅱ期。拟赤梢鱼sox3基因cDNA全长为1800 bp(GenBank登录号:MT952206),编码299个氨基酸,存在保守的HMG(histidine,methionine,glycine-rich)结构域。氨基酸序列比对和系统进化树分析结果显示,拟赤梢鱼SOX3蛋白与斑马鱼(Danio rerio)和翘嘴鲌(Culter alburnus)亲缘关系最近。此外,sox3基因在拟赤梢鱼卵巢中表达量最高,其次是脑和眼睛,在精巢和其他组织中微量表达;在性腺分化过程中,sox3基因在卵巢中表达量显著高于未分化性腺和精巢,在卵巢发育阶段表达量不断升高,而在精巢中持续低水平表达。综上,本研究推测sox3基因主要参与拟赤梢鱼卵巢的分化和发育。展开更多
文摘Leptocephalus larvae are the unique stage of larval development in all groups of fishes from the superorder Elopomorpha (Anguilliformes, Elopiformes and Notacanthiformes). To explain the leptocephalus strategy of larval development, various attempts have been made on the morphology, physiology and biochemistry of leptocephalus larvae. However, the feeding mechanism of leptocephalus larvae is still unknown. The Japanese eel (Anguilla japonica) larvae were found to have well developed scotopic vision, mechanoreception and chemoreception. Both early and leptocephalus larvae of Japanese eel actively ingested a kind of paste food by first touching the food with their snout and then tearing off a big mouthful of the paste with their sharp teeth. Chemoreception was shown to be critical to elicit the feeding response. Feeding by Sflex posture from a distance might be of some significance for the early larvae to catch movable food. It is proposed that that the natural food of Japanese eel larvae would be relatively large, rather soft, inactive and negatively phototactic. The developmental mode of sensory system and behavior of Japanese eel larvae seems to be similar to some deep sea fishes but contrast with most marine teleost fishes.
文摘为初步阐明拟赤梢鱼(Pseudaspius leptocephalus)卵巢发育特征及sox3(sry related high mobility group box 3)基因在其卵巢发育过程中的作用,本研究通过组织切片观察了拟赤梢鱼卵巢早期发育过程,利用RACE技术克隆了该鱼sox3基因c DNA全长序列,并进行生物信息学分析;利用实时荧光定量PCR技术分析了sox3基因在拟赤梢鱼不同组织及性腺不同发育时期的表达模式。结果显示,拟赤梢鱼卵巢在孵化后45 d分化形成,160 d时由Ⅰ期进入Ⅱ期,孵化后360 d,卵巢仍处于Ⅱ期。拟赤梢鱼sox3基因cDNA全长为1800 bp(GenBank登录号:MT952206),编码299个氨基酸,存在保守的HMG(histidine,methionine,glycine-rich)结构域。氨基酸序列比对和系统进化树分析结果显示,拟赤梢鱼SOX3蛋白与斑马鱼(Danio rerio)和翘嘴鲌(Culter alburnus)亲缘关系最近。此外,sox3基因在拟赤梢鱼卵巢中表达量最高,其次是脑和眼睛,在精巢和其他组织中微量表达;在性腺分化过程中,sox3基因在卵巢中表达量显著高于未分化性腺和精巢,在卵巢发育阶段表达量不断升高,而在精巢中持续低水平表达。综上,本研究推测sox3基因主要参与拟赤梢鱼卵巢的分化和发育。
