久效磷对雄性金鱼分泌细胞超微结构的影响

利用电镜技术观察了久效磷暴露条件下,金鱼中腺垂体促性腺激素细胞、生长激素细胞和促甲状腺激素细胞以及精巢Leydig氏细胞超微结构的变化。结果表明,久效磷对中腺垂体分泌细胞及精巢Leydig氏细胞膜系统的损伤最为严重,主要表现为垂体3种分泌细胞核膜水肿、局部溶解,染色质有不同程度的收缩现象,粗面内质网水肿,部分溶解呈空泡状;精巢Leydig氏细胞核膜局部溶解,染色质轻微凝聚,粗面内质网水肿,局部溶解,线粒体内嵴水肿、局部溶解。久效磷对金鱼中腺垂体促性腺激素细胞、生长激素细胞和促甲状腺激素细胞及精巢Leydig氏细胞结构的损伤是影响内分泌细胞激素分泌功能的原因之一。     

LOCALIZATION OF A PUTATIVE EPIBOLY-DETERMINING FACTOR IN OOCYTES OF THE GOLDFISH (CARASSIUS AURATUS)

It is unknown whether cytoplasmic determinants in goldfish eggs are asymmetrically localized beforematuration. In this study fully grown goldfish oocytes with infact germinal vesicles (GVs) were ligated withbaby hair loops along desired planes into two parts, mature in vitro, and inseminated. Embryos developedfrom the animal halves with GV of oocytes ligated along the equator un unable to undergoepiboly, while those developed from the GV-containing parts of oocytes ligated along the animal-vegetal axiswere able to. Also, embryos developed from the animal halves obtained from fertilized eggs could undergo epiboly. From there results, it was postulated that the goldfish's premature oocyte possessed a putativefactor in the vegetal hemisphere which was responsible for epiboly of the embryonic cells.     

Localization of a putative epiboly-determining factor in oocytes of the goldfish (Carassius auratus)

It is unknown whether cytoplasmic determinants in goldfish eggs are asymetrically localized before maturation. In this study fully grown goldfish oocytes with intact germinal vesiles (GVs) were ligated with baby hair loops along desired planes into two parts, matured in vitro, and inseminated. Embryos developed from the animal halves with GV of oocytes ligated along the equator were unable to undergo epiboly, while those developed from the GV-containing parts of oocytes ligated along the animal-vegetal axis were able to. Also, embryos developed from the animal halves obtained from fertilized eggs could undergo epiboly. From these results, it was postulated that the goldfish's premature oocyte possessed a putative factor in the vegetal hemisphere which was responsible for epiboly of the embryonic cells. This work was supported by the NSFC and the “Climb Plan B” (PD-B6-1-1) of the Chinese Commission of Science and Technology. Contribution No. 2915 from the Institute of Oceanology, Chinese Academy of Sciences.     

Fish community responses to invasive fish removal and installation of an exclusion barrier at Lake Ohinewai,Waikato

Introduced common carp (Cyprinus carpio) are a recognised threat to New Zealand’s freshwater ecosystems. In 2011, an invasive fish removal programme was undertaken in 16.8 ha Lake Ohinewai, a Waikato riverine lake. Active fish removal using netting and boat electrofishing was supported by installation of a one-way exclusion barrier on the outflow to Lake Ohinewai. The barrier was designed to allow fish passage downstream out of the lake, while preventing adult carp from moving upstream. The estimated carp population was reduced from 8,548 fish (5,863–12,937, 95% confidence limits) in 2011–454 fish (251–889, 95% CL) in 2014. However, by 2016 the carp population had recovered to 2,063 fish (1,070–4,328, 95% CL) with increased abundance in invasive brown bullhead catfish (Ameiurus nebulosus) also observed. This research demonstrates that carp populations can be reduced to low abundances in the short to medium term, but continued removal will be required for on-going control.     

饥饿对金鱼卵巢型和脑型芳香化酶基因表达的影响研究

采用RT-PCR技术,研究了金鱼性腺型芳香化酶基因(CYP19A)和脑型芳香化酶基因(CYP19B)的表达对饥饿胁迫的响应机制.研究结果表明:正常投喂的雌性金鱼中CYP19A基因mRNA在卵巢、肝脏、肾脏、肌肉、鳃、头肾、脾脏、脑、肠和心脏10个组织均有表达,表达量呈现递减趋势;饥饿胁迫后,CYP19A基因mRNA在脑和卵巢中表达的变化规律基本一致,即饥饿5d时表达量显著降低(P<0.05),随后表达水平维持稳定.正常投喂的雌性金鱼CYP19B基因mRNA在脑、头肾、性腺、脾、肌肉和心脏6个组织中表达呈现递减趋势;CYP19B基因mRNA在脑和卵巢中的表达量,在饥饿5d时表达量显著降低(P<0.05),随后表达水平维持稳定.这些结果说明,雌性金鱼在饥饿条件下,性激素合成关键酶基因在脑和卵巢中的表达量显著降低,可能影响卵巢发育。