鳜鱼肌肉的氨基酸及无机元素

<正> 鳜鱼是名贵的鱼类,开展鱼类营养分析研究,具有实践及理论意义。材料与方法 1988年4月22日子天津蓟县于桥水库取体长296—372毫米的鳜鱼5尾,性腺发育到     

鳜鱼病毒结构特征与形态发生

从患流行病的鳜鱼脾脏组织超微切片中观察到大量的病毒颗粒。该完整病毒颗粒直径约 135nm± 10 ,具包膜。成熟病毒核壳体约 90nm± 5 ,包膜厚度约 18nm± 3,核壳体与包膜间的非电子致密区约有 2 7nm± 2。通过对不同发病阶段发病鳜鱼脾脏组织切片的电镜观察 ,在感染初期的鳜鱼脾脏组织观察到病毒的吸附及典型的内吞入侵方式 ,在感染中后期的脾脏组织细胞质内观察到病毒发生基质及病毒核壳、包膜形成与病毒的释放。此外 ,在染病鳜鱼的肾、心、肝、及鳃组织亦观察到相同结构的病毒粒子。回接实验证实该病毒为引起鳜鱼暴发流行病的病原     

鳜鱼病毒结构特征与形态发生

从患流行病的鳜鱼脾脏组织超微切片中观察到大量的病毒颗粒.该完整病毒颗粒直径约135nm±10,具包膜.成熟病毒核壳体约90nm±5,包膜厚度约18nm±3,核壳体与包膜间的非电子致密区约有27nm±2.通过对不同发病阶段发病鳜鱼脾脏组织切片的电镜观察,在感染初期的鳜鱼脾脏组织观察到病毒的吸附及典型的内吞入侵方式,在感染中后期的脾脏组织细胞质内观察到病毒发生基质及病毒核壳、包膜形成与病毒的释放.此外,在染病鳜鱼的肾、心、肝、及鳃组织亦观察到相同结构的病毒粒子.回接实验证实该病毒为引起鳜鱼暴发流行病的病原.     

梁子湖鳜鱼的生物学

1956年1月至1957年3月,作者在梁子湖进行了鳜鱼[Siniperca chuatsi(Basilew-sky)]生态学的调查。材料主要取自梁子镇鲜鱼收购站。每月取材的次数自3次至10次不等,一般5次以上。在生殖季节,有时直接从渔船取得材料。材料取得后,除记录体长、体重外,还进行了性腺发育情形、胃内食物等观察,然后取下鳃盖骨,以作测定年龄之用。先后共解剖了360尾鳜鱼。     

梁子湖鳜鱼的生物学

1956年1月至1957年3月,作者在梁子湖进行了鳜鱼[Siniperca chuatsi(Basilewsky)]生态学的调查。材料主要取自梁子镇鲜鱼收购站。每月取材的次数自3次至10次不等,一般5次以上。在生殖季节,有时直接从渔船取得材料。材料取得后,除记录体长、体重外,还进行了性腺发育情形、胃内食物等观察,然后取下鳃盖骨,以作测定年龄之用。先后共解剖了360尾鳜鱼。     

鳜鱼口咽腔味蕾和行为反应特性及其对捕食习性的适应

用扫描电镜观察和行为学实验研究鳜鱼口咽腔味蕾形态和分布及吞食行为反应特性，结果表明，鳜鱼口咽腔味蕾丰富，几乎都是Ｉ型和Ⅱ型味蕾，着生于表皮乳突上，主要分布于上颌骨齿周围及内侧，下颌齿周围及外侧，舌前中区，下鳃骨细齿内侧等部位，其它区域分布较少，鳜鱼口咽腔味蕾对食物味道和软硬均非常敏感，鳜鱼仅吞食同时具有一定味道和软硬度的食物，本文探讨了鳜鱼口咽腔味蕾的结构功能关系及其对捕食习性的适应意义。     

鳜鱼头肾的组织发生及成鱼头肾B淋巴细胞的分布

通过整体连续切片,研究了鳜鱼不同发育时期的头肾结构,并利用原位PCR方法检测了B淋巴细胞在鳜鱼头肾中的分布。在孵化后第1d观察到了肾组织,主要由肾小管组成。尔后头肾的发育经历了三个结构和功能的转变。第一个阶段为孵化后第1d到第7d,头肾作为滤过性器官存在,由肾小管及少量淋巴细胞组成。第二个阶段从第8d到第36d,是一个功能混合型阶段,头肾中既有肾小管,又有造血组织;随时间推移,肾小管数量减少,淋巴细胞数量剧增。紧接着进入第三个阶段：肾小管完全消失,头肾中开始出现大量的嗜铬细胞,头肾作为淋巴-肾上腺组织而存在。肾上腺首先出现在头肾前端,随发育成熟,集中分布于头肾门静脉周围。IgM在鳜头肾中大量表达,IgM分泌细胞分布于整个头肾组织,在血管周围有集中趋势[动物学报51(3)：440—446,20051。     

三种鳜鱼骨骼肌生长及相关调控基因表达比较

通过制作骨骼肌石蜡切片研究了鳜、斑鳜及斑鳜(♀)×鳜(♂)杂交一代不同发育时期(孵化后10D、20D、30D、60D、90D)骨骼肌肌纤维的生长特征,同时,利用q PCR技术分析了肌肉中myostatin、Myo D、myogenin三个基因m RNA的表达变化。结果表明,3种鳜鱼全长均随日龄呈增大趋势,种间生长差异显著,鳜生长最快,斑鳜最慢,杂交一代介于斑鳜和鳜之间。不同发育时期,3种鳜鱼骨骼肌肌纤维数目较为接近,增生生长种间无明显差异,而肌纤维平均直径大小与其生长快慢间呈正相关,表明不同鳜鱼种间生长差异主要由肌肉肥大生长引起的。鳜、斑鳜和杂交一代myostatin m RNA在D20出现表达高峰,之后表达量呈下降趋势。Myo D在D10、D20表达水平较高,后期表达水平下降;Myogenin在D20时表达量最低,之后,鳜表达量升高最为明显,杂交一代次之,斑鳜保持平稳。不同种类鳜鱼肌肉生长差异与3种基因表达差异间存在一定相关性。     

qRT-PCR分析鳜鱼内参基因的筛选

选择合适的内参基因是提高实时荧光定量PCR分析(quantitative real-time polymerase chain reaction,qRT-PCR)准确性的首要条件。本实验采取鳜鱼8个不同胚胎发育阶段、5个胚后发育时期和8个成鱼组织为研究对象,应用qRT-PCR技术,分析了RPL13、RPL19、EF1a、RPL13a、B2M、hprt1和rps29七个内参基因的表达稳定情况。经GeNorm软件分析发现,B2M和RPL13a在鳜鱼成鱼不同组织中表达最稳定;在胚后不同时期中表达最稳定的是EF1a和RPL13a;EF1a和B2M是在不同胚胎发育阶段中表达最稳定的两个基因。根据内参基因标准化因子的配对差异分析V_(n/n+1),在鳜鱼不同组织和不同发育阶段中,均使用两个最稳定表达的内参基因即可达到准确校正的目的。因此,该实验结果为鳜鱼基因表达分析时内参基因的选择提供了参考。     

鳜鱼胰蛋白酶和淀粉酶与胃蛋白酶原基因的克隆与序列分析

采用RT-PCR及RACE法,克隆得到鳜鱼(Siniperca chuatsi)肝胰脏胰蛋白酶(trypsin, Try)、淀粉酶(amylase, Amy)基因 cDNA全序列.结果表明,鳜鱼Try基因cDNA全长为896 bp,其中开放阅读框 (open reading frame,ORF)为744 bp,编码247个氨基酸. 序列同源性分析发现,鳜鱼Try与 斑马鱼(Danio rerio)、非洲爪蟾(Xenopus laevis)、 小鼠Try和人TRY氨基酸序列同源性分别为81.4%、75.3%、74.5%和71.4%.鳜鱼Amy 基因cDNA全长为1 647 bp,其中ORF为1 539 bp,编码512个氨基酸.鳜鱼Amy与斑马鱼 、非洲爪蟾、小鼠Amy和人AMY氨基酸序列同源性分别为79.7%、75.4%、71.9%和70.9%. 同时对鳜鱼基因组进行PCR,获得鳜鱼Try、Amy与胃蛋白酶原(pepsinogen, Pep)全基因组DNA序列.序列分析表明,鳜鱼Try基因由4个内含子和5个外显子组成,全长1 362 bp;鳜鱼Amy基因由8个内含子和9个外显子组成,全长4 267 bp;鳜鱼Pep基因由8个内含子和9个外显子组成,全长 4 032 bp,与其它脊椎动物基因结构相似.应用Genome walker方法在鳜鱼克隆得到长度分别为1 189 bp、413 bp和527 bp的Try、Amy和Pep基因的5′侧翼区序列以及1段长为704 bp的Pep 基因3′侧翼区序列,并利用相关软件预测其中具有多个可调节其表达的调控元件.鳜鱼Try、Am y和Pep基因组全序列的克隆及其序列、结构分析和分子系统进化等的研究,为鱼类消化代谢相关基因的生理功能及表达调控机理进一步研究提供依据.     

北草蜥和中国石龙子几种消化酶活力比较研究

应用酶学分析法测定了越冬后北草蜥和中国石龙子的胃、肠、胰组织中蛋白酶、淀粉酶、纤维素酶的活力。结果表明：不同组织中的消化酶活力差异显著;同一组织中不同消化酶的活力差异显著;不同动物的同一组织中消化酶活力也有差异。这些差异说明消化酶的活力与动物种类和器官的分化有关,并受食物组成和遗传因素的影响,产生了不同的酶活力分布。这也是生物长期适应环境,形成不同的代谢水平的结果。     

Developmental changes in the activities of prostaglandin synthesizing enzymes in the digestive and immune systems of rat

The developmental changes of prostaglandin (PG) synthesizing enzymes in the digestive system (stomach and small intestine) and the immune system (spleen and thymus) of rats were investigated. In all the digestive organs, the predominant PG produced from PGH2 changed at around 2 weeks after birth to another PG. Further, the predominant activities of PG synthesizing enzymes were different organ by organ in the digestive system. In the case of the immune system, only the activity of PGD2 synthesizing enzyme displayed a significant increase during development and the activities of other PG synthesizing enzymes remained insignificant throughout the development. These results suggest that PGs may play important roles during the development of each organ.     

Unique and conserved aspects of gut development in zebrafish

Although the development of the digestive system of humans and vertebrate model organisms has been well characterized, relatively little is known about how the zebrafish digestive system forms. We define developmental milestones during organogenesis of the zebrafish digestive tract, liver, and pancreas and identify important differences in the way the digestive endoderm of zebrafish and amniotes is organized. Such differences account for the finding that the zebrafish digestive system is assembled from individual organ anlagen, whereas the digestive anlagen of amniotes arise from a primitive gut tube. Despite differences of organ morphogenesis, conserved molecular programs regulate pharynx, esophagus, liver, and pancreas development in teleosts and mammals. Specifically, we show that zebrafish faust/gata-5 is a functional ortholog of gata-4, a gene that is essential for the formation of the mammalian and avian foregut. Further, extraembryonic gata activity is required for this function in zebrafish as has been shown in other vertebrates. We also show that a loss-of-function mutation that perturbs sonic hedgehog causes defects in the development of the esophagus that parallel those associated with targeted disruption of this gene in mammals. Perturbation of sonic hedgehog also affects zebrafish liver and pancreas development, and these effects occur in a reciprocal fashion, as has been described during mammalian liver and ventral pancreas development. Together, these data define aspects of digestive system development necessary for the characterization of zebrafish mutants. Given the similarities of teleost and mammalian digestive physiology and anatomy, these findings have implications for developmental and evolutionary studies as well as research of human diseases, such as diabetes, liver cirrhosis, and cancer.     

Ribosome biogenesis protein Urb1 acts downstream of mTOR complex 1 to modulate digestive organ development in zebrafish

Ribosome biogenesis is essential for the cell growth and division. Disruptions in ribosome biogenesis result in developmental defects and a group of diseases, known as ribosomopathies. Here, we report a mutation in zebrafish urb1, which encodes an essential ribosome biogenesis protein. The urb1 cq31 mutant exhibits hypoplastic digestive organs, which is caused by impaired cell proliferation with the differentiation of digestive organ progenitors unaffected. Knockdown of mtor or raptor leads to similar hypoplastic phenotypes and reduced expression of urb1 in the digestive organs. Overexpression of Urb1 results in overgrowth of digestive organs, and can efficiently rescue the hypoplastic liver and pancreas in the mtor and raptor morphants. Reduced syntheses of free ribosomal subunits and impaired assembly of polysomes are observed in the urb1 mutant as well as in the mtor and raptor morphants, which can be rescued by the Urb1 overexpression. These data demonstrate that Urb1 plays an important role in governing ribosome biogenesis and protein synthesis downstream of mammalian/mechanistic target of rapamycin complex 1(mTORC1), thus regulating the development of digestive organs. Our study indicates the requirement of hyperactive protein synthesis for the digestive organ development.     

北草蜥几种消化酶活力比较

应用酶学分析法测定了越冬后北草蜥胃、肠组织中蛋白酶、淀粉酶、纤维素酶的活力。结果表明 ,不同年龄、性别的北草蜥同一组织中消化酶活力有显著差异 ;不同地理种群的北草蜥同一组织中消化酶活力有显著差异 ;不同消化酶在北草蜥同一组织中的活力有显著差异 ;在北草蜥不同的组织中同一消化酶的活力有显著差异。说明北草蜥消化酶的活力与年龄、性别、部位和地理环境等因素有关 ,受食物组成、能量需求和遗传等因素的影响 ,产生了不同的酶活力和分布。这也说明生物长期适应环境 ,形成了不同的代谢水平     

Visualizing digestive organ morphology and function using differential fatty acid metabolism in live zebrafish

Lipids are essential for cellular function as sources of fuel, critical signaling molecules and membrane components. Deficiencies in lipid processing and transport underlie many metabolic diseases. To better understand metabolic function as it relates to disease etiology, a whole animal approach is advantageous, one in which multiple organs and cell types can be assessed simultaneously in vivo. Towards this end, we have developed an assay to visualize fatty acid (FA) metabolism in larval zebrafish (Danio rerio). The method utilizes egg yolk liposomes to deliver different chain length FA analogs (BODIPY-FL) to six day-old larvae. Following liposome incubation, larvae accumulate the analogs throughout their digestive organs, providing a comprehensive readout of organ structure and physiology. Using this assay we have observed that different chain length FAs are differentially transported and metabolized by the larval digestive system. We show that this assay can also reveal structural and metabolic defects in digestive mutants. Because this labeling technique can be used to investigate digestive organ morphology and function, we foresee its application in diverse studies of organ development and physiology.     

Fine structure and absorption of ferritin in the digestive organs of Loligo vulgaris and L. Forbesi (Cephalopoda,Teuthoidea)

The digestive organs possibly involved in food absorption in Loligo vulgaris and L. forbesi are the caecum, the intestine, the digestive gland, and the digestive duct appendages. The histology and the fine structure showed that the ciliated organ, the caecal sac, and the intestine are lined with a ciliated epithelium. The ciliary rootlets are particularly well developed in the ciliated organ, apparently in relation to its function of particle collection. Mucous cells are present in the ciliated organ and the intestine. Histologically, the digestive gland appears rather different from that of other cephalopods. However, the fine structure of individual types of squid digestive cell is actually similar to that of comparable organs in other species, and the squid cells undergo the same stages of activity. Digestive cells have a brush border of microvilli, and numerous vacuoles, which sometimes contain “brown bodies.” However, no “boules” (conspicuous protein inclusions of digestive cells in other species) could be identified in their cytoplasm; instead only secretory granules are present. In the digestive duct appendages, numerous membrane infoldings associated with mitochondria are characteristic features of the epithelial cells in all cephalopods. Two unusual features were observed in Loligo: first, the large size of the lipid inclusions in the digestive gland, in the caecal sac, and in the digestive duct appendages; and second, the large number of conspicuous mitochondria with well-developed tubular cristae. When injected into the caecal sac, ferritin molecules can reach the digestive gland and the digestive duct appendages via the digestive ducts, and they are taken up by endocytosis in the digestive cells. Thus, it appears that the digestive gland of Loligo can act as an absorptive organ as it does in other cephalopods.     

Developmental changes in digestive physiology of nestling house sparrows, Passer domesticus

Six decades of studies have speculated that digestive capacity might limit avian growth rate or that developmental changes in the gut might determine developmental changes in digestive efficiency. However, there are no studies on digestive enzymes during avian development, except for studies on mainly domestic birds that exhibit the precocial mode of development. We studied alimentary organ masses, intestinal enzyme activities (sucrase, maltase, isomaltase, aminopeptidase-N), and pancreatic enzyme activities (amylase, trypsin, chymotrypsin) during development of a wild passerine bird exhibiting the altricial mode of development. Wild nestling house sparrows were studied immediately after removal from the nest (days 0, 3, 6 of age; day 0=hatch), whereas captives were raised in the laboratory beginning day 3 on a formulated casein/starch-based diet until fledging age (after day 12). Digestive biochemistry was dynamic. Tissue-specific activities of some digestive enzymes continued to increase through fledging, by >10 times in some cases (e.g., sucrase and maltase in midintestine). Total pancreatic amylase activity increased 100 times between hatch and day 12 through a combination of increases in tissue-specific activity and pancreas mass. House sparrows differ from poultry, in whom after about 2 wk of age the specific activity of intestinal and pancreatic digestive enzymes is generally constant or declines during development. The data on intestinal and pancreatic enzymes help explain why digestive efficiency of nestling house sparrows improves with age, and the data seem consistent with the idea that digestive capacity might limit feeding rate and hence growth rate.     

化学反应器理论与食草动物的消化对策

动物的消化道结构直接决定动物从食物中获得能量和营养物质的速率。最优消化道结构和消化对策是动物充分利用食物中的营养物质同时使能量净获得速率最大的决定因素。利用化学反应器模型及理论可以定量地描述动物的消化过程,阐述动物采取的消化对策和分析食物的消化动力等。章综述了化学反应器理论在食草消化对策中可能的应用。包括理想的化学反应器模型、食草动物的类型、消化对策以及化学反应器理论的局限性等几个方面。     

Nil per os encodes a conserved RNA recognition motif protein required for morphogenesis and cytodifferentiation of digestive organs in zebrafish

Digestive organ development occurs through a sequence of morphologically distinct stages, from overtly featureless endoderm, through organ primordia to, ultimately, adult form. The developmental controls that govern progression from one stage to the next are not well understood. To identify genes required for the formation of vertebrate digestive organs we performed a genetic screen in zebrafish. We isolated the nil per os (npo) mutation, which arrests morphogenesis and cytodifferentiation of the gut and exocrine pancreas in a primordial state. We identified the npo gene by positional cloning. It encodes a conserved protein, with multiple RNA recognition motifs, that is related to the yeast protein Mrd1p. During development npo is expressed in a dynamic fashion, functioning cell autonomously to promote organ cytodifferentiation. Antisense-mediated knockdown of npo results in organ hypoplasia, and overexpression of npo causes an overgrowth of gastrointestinal organs. Thus, npo is a gene essential for a key step in the gut morphogenetic sequence.