采用显微观察和测绘法对条斑星鲽早期生长发育的数量和形态特征进行了系统的观察和测量。结果表明,条斑星鲽成熟卵子为悬浮性、端黄卵,圆球形,卵径1.7—1.9mm,无油球。在水温(9.0±0.5)℃条件下,受精卵经196.3h孵化出膜。在水温12—14℃条件下,7日龄(DAH,days after hatching)仔鱼卵黄囊消耗殆尽,开口,肛门与外界相通,开始进入外源性营养阶段。仔鱼开口饵料为轮虫,8日龄仔鱼开始摄食轮虫,12日龄开始摄食卤虫无节幼体,30日龄开始进行配合饲料转化,40日龄后苗种摄食配合饲料良好。生活史无鳔。脊椎骨末端上曲发生在21日龄,至28日龄完成。70日龄幼鱼鳞片和侧线已形成,鳍条数量与成体完全一致。变态过程:32日龄苗种进入变态期,左侧眼睛开始上移,42日龄眼睛转移至头顶,50日龄眼睛转到右侧,完成变态。研究了鳍的发生及生长过程:背鳍、胸鳍、腹鳍、尾鳍、臀鳍分别发生于19、0、20、19、10天,至50日龄幼鱼,除胸鳍外其它鳍的鳍条数与成鱼一致。
Natural resistance associated macrophage protein (Nramp) is an innate resistance protein to intracellular parasites, which is expressed plentifully in macrophage cells. Nramp has been studied in mouse, human, cattle, ...
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Natural resistance associated macrophage protein (Nramp) is an innate resistance protein to intracellular parasites, which is expressed plentifully in macrophage cells. Nramp has been studied in mouse, human, cattle, rainbow trout and channel catfish. However, little was known about the structure of Pagrus major Nramp. In order to get the complete sequence of Pagrus major Nramp, a pair of primer is designed according to a 200bp known sequence of Pagrus major Nramp cDNA. By the use of SMART RACE, the full Nramp of Pagrus major cDNA about 5 000 bp was obtained, including about 200 bp 5′ terminal region (UTR), complete encoding region and 3′ terminal region. There were 3 ployA signals, which showed many possibilities of cutting at 3′ terminal region. The character of Pagrus major Nramp nucleotide sequence and deduced amino acid sequence are analyzed. 12 putative transmembrane(TM) regions, a consensus transport motif (CTM), a predicted protein kinase C phosphroylation site and three predicted N-link glycosylation sites are indicated in its deduced amino acid sequence. The ’consense transport motif’ CTM is located between TM8 and TM9. Furthermore, a protein kinase C phosphroylation site and three N-link glycosylation sites were predicted. The alignment of amino acid sequences between Pagrus major Nramp cDNA and several animals is analyzed and the deduced amino acid sequence of Pagrus major Nramp had 77.8%, 83.0%, 82.3%, 80.0%, 81.1%, 60.4%, 70.3%, 58.5%, 69.5% identity with rainbow trout α(AAD20721), rainbow trout β (AAD20722), channel catfish(AF400108), fathead minnow (AAF01778), common carp (CAB60196), mouse 1(AAA39838), mouse 2(AAC42051), human 1(D50403), human 2(NP-000608), respectively. The alignment reveals high conservation in TM and CTM regions. Analysis result makes us get familiar with the structure and character of fish Nramp, furthermore, offers some information for the enhancement of immunity of fish and genetic amelioration on fish breeding.
Electron microscopic examinations of ultrathin sections reveal the presence of spherical virus like particles in the digestive gland, kidney, and the intestine of moribund scallop Chlamys farreri collected during a se...
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Electron microscopic examinations of ultrathin sections reveal the presence of spherical virus like particles in the digestive gland, kidney, and the intestine of moribund scallop Chlamys farreri collected during a severe mortality in Jiaozhou Bay (Qingdao, China) in 2000. The virions are approximately 130 to 170 nm in diameter and have a bilaminal envelope, while the nucleocapsids are 90-140 nm. The virus occurs and distributes in the cytoplasmic vesicles of infected cells, and it is arranged in a scattered form without occluding protein. The viral particles are consistent in size and morphology in preparations derived from the isolation and also from ultrathin sections. The spikes of envelope are clearly observed with negative staining. By the same methods, this virus was not found in the healthy scallop, indicating that this virus might be the causative aetiology for the abnormal mortality.
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