Adaptive evolution of a duplicated pancreatic ribonuclease gene in a leaf-eating monkey

Although the complete genome sequences of over 50 representative species have revealed the many duplicated genes in all three domains of life(1-4), the roles of gene duplication in organismal adaptation and biodiversity are poorly understood. In addition,

The unusual adaptive expansion of pancreatic ribonuclease gene in carnivora

Pancreatic ribonuclease (RNASE1) is a digestive enzyme that has been recognized to be one of the most attractive model systems for molecular evolutionary studies. The contribution of RNASE1 gene duplication to the functional adaptation of digestive physio

Duplication and functional diversification of pancreatic ribonuclease (RNASE1) gene

Adaptation is one of the most fundamental issues in the studies of organismal evolution. Pancreatic ribonuclease is a very important digestive enzyme and secreted by the pancreas. Numerous studies have suggested that RNASE1 gene duplication is closely related to the functional adaptation of the digestive system in the intestinal fermentation herbivores. RNASE1 gene thus becomes one of the most important candidate genetic markers to study the molecular mechanism of adaptation of organisms to the feeding habit. Interestingly, RNASE1 gene duplication has also been found in some non-intestinal fermentation mammals, suggesting that RNASE1 gene may have produced novel tissue specificity or functions in these species. In this review, RNASE1 gene and its implications in adaptive evolution, especially in association with the feeding habit of organisms, are summarized.

Adaptive Evolution of Digestive RNASE1 Genes in Leaf-Eating Monkeys Revisited: New Insights from Ten Additional Colobines

Pancreatic RNase genes implicated in the adaptation of the colobine monkeys to leaf eating have long intrigued evolutionary biologists since the identification of a duplicated RNASE1 gene with enhanced digestive efficiencies in Pygathrix nemaeus. The recent emergence of two contrasting hypotheses, that is, independent duplication and one-duplication event hypotheses, make it into focus again. Current understanding of Colobine RNASE1 gene evolution of colobine monkeys largely depends on the analyses of few colobine species. The present study with more intensive taxonomic and character sampling not only provides a clearer picture of Colobine RNASE1 gene evolution but also allows to have a more thorough understanding about the molecular basis underlying the adaptation of Colobinae to the unique leaf-feeding lifestyle. The present broader and detailed phylogenetic analyses yielded two important findings: 1) All trees based on the analyses of coding, noncoding, and both regions provided consistent evidence, indicating RNASE1 duplication occurred after Asian and African colobines speciation, that is, independent duplication hypothesis; 2) No obvious evidence of gene conversion in RNASE1 gene was found, favoring independent evolution of Colobine RNASE1 gene duplicates. The conclusion drawn from previous studies that gene conversion has played a significant role in the evolution of Colobine RNASE1 was not supported. Our selective constraint analyses also provided interesting insights, with significant evidence of positive selection detected on ancestor lineages leading to duplicated gene copies. The identification of a handful of new adaptive sites and amino acid changes that have not been characterized previously also provide a necessary foundation for further experimental investigations of RNASE1 functional evolution in Colobinae.

用酶联免疫吸附试验快速检测虹鳟的传染性胰脏坏死病病毒

<正> 我国于1987年从进口的虹鳟中分离了传染性胰脏坏死病病毒(Infectious pancreatic necrosis virus简称IPNV),并进行了血清学鉴定。由于病鱼没有特有的临床症状,所以迅速查找鱼体内特异性的病毒是十分必要的。本文报道了用酶联免疫吸附试验(ELISA)鉴定细胞培养中分离出的IPN病毒及从鱼组织中直接检测IPN

虹鳟传染性胰脏坏死病病毒(IPNV)的初步研究

山西省虹鳟试验场用从日本引进的鱼卵孵化的虹鳟稚鱼暴发流行病,死亡率高达90％以上。经组织培养分离到病毒,能在鲑鳟细胞系中产生细胞病变,形成直径0.5—1mm的空斑。感染健康虹鳟稚鱼能复制出与天然发病相同的症状和死亡率。病毒对氯仿不敏感,耐酸、耐热。病毒负染后电镜观察为直径55—65mm的二十面体颗粒,无囊膜,具单层衣壳。经血清学鉴定为传染性胰脏坏死病病毒(Infectious pancreatic necrosis virus简称IPNV)在血清学交叉中和反应中与抗IPN-Sp株的抗血清有强烈的交叉反应,

Molecular characterization and expression pattern of AFPIV during embryogenesis in gibel carp(Carassiu auratus gibelio)

As a new type of AFPs, AFPIV has been firstly identified in longhorn sculpin (Myoxocephalus octodecimspinosus), and in recent years, its cDNA and amino acid sequence have been reported, and its pancreatic synthesis has been firstly reported in polar fish. However, its expression patterns during fish embryogenesis have not been elucidated yet. By differential screening, we cloned the CagAFPIV in gibel carp, Carassius auratus gibelio, demonstrated its predominant expression during embryogenesis. RT-PCR detection revealed that CagAFPIV was first transcribed from blastula stage and kept a high level during embryogenesis and declined remarkably in hatched larva. In situ hybridization revealed that CagAFPIV transcripts were firstly distributed over the margin and marginal blastomere in blastula stage embryos, at the early-gastrula stage the positive signals distributed in the marginal cells and the internalization cells, and later restricted to the cells the yolk syncytial layer (YSL) from later gastrula stage to larva stage. Consistently, the CagAFPIV protein also kept a high level during embryogenesis, and the high protein level retained some days after the larva hatched. Our work, for the first time, revealed the dynamic expression and distribution of CagAFPIV during embryogenesis.

Zebrafish eaf1 and eaf2/u19 Mediate Effective Convergence and Extension Movements through the Maintenance of wnt11 and wnt5 Expression

Studies have attributed several functions to the Eaf family, including tumor suppression and eye development. Given the potential association between cancer and development, we set forth to explore Eaf1 and Eaf2/U19 activity in vertebrate embryogenesis, using zebrafish. In situ hybridization revealed similar eaf1 and eaf2/u19 expression patterns. Morpholino-mediated knockdown of either eaf1 or eaf2/u19 expression produced similar morphological changes that could be reversed by ectopic expression of target or reciprocal-target mRNA. However, combination of Eaf1 and Eaf2/U19 (Eafs)-morpholinos increased the severity of defects, suggesting that Eaf1 and Eaf2/U19 only share some functional redundancy. The Eafs knockdown phenotype resembled that of embryos with defects in convergence and extension movements. Indeed, knockdown caused expression pattern changes for convergence and extension movement markers, whereas cell tracing experiments using kaeda mRNA showed a correlation between Eafs knockdown and cell migration defects. Cardiac and pancreatic differentiation markers revealed that Eafs knockdown also disrupted midline convergence of heart and pancreatic organ precursors. Noncanonical Wnt signaling plays a key role in both convergence and extension movements and midline convergence of organ precursors. We found that Eaf1 and Eaf2/U19 maintained expression levels of wnt11 and wnt5. Moreover, wnt11 or wnt5 mRNA partially rescued the convergence and extension movement defects occurring in eafs morphants. Wnt11 and Wnt5 converge on rhoA, so not surprisingly, rhoA mRNA more effectively rescued defects than either wnt11 or wnt5 mRNA alone. However, the ectopic expression of wnt11 and wnt5 did not affect eaf1 and eaf2/u19 expression. These data indicate that eaf1 and eaf2/u19 act upstream of noncanonical Wnt signaling to mediate convergence and extension movements.

Isolation, characterization and genome sequence of a birnavirus strain from flounder Paralichthys olivaceus in China

A birnavirus strain, Paralichthys olivaceus birnavirus (POBV), was isolated and characterized from cultured flounder in China, and its complete genomic sequence was subsequently determined. The virus could induce cytopathic effects (CPE) in four of seven fish cell lines and was resistant to chloroform, 5-iodo-2'-deoxyuridine, acid and alkaline pH, and heat treatment. Purified virus particles had a typical icosahedral shape, with a diameter of approximately 55-60 nm. The genomic segments A and B of POBV were 3,091 and 2,780 bp in length and shared many of the features of the members of the family Birnaviridae. Segment A contained two partially overlapping ORFs encoding a polyprotein, pVP2-VP4-VP3, and a nonstructural protein, VP5, while segment B had only one ORF encoding for the VP1, a viral RNA-dependent RNA polymerase (RdRp). This is the first report about a birnavirus strain from a new non-salmonid host in China and its complete genome sequence.

Enzymatic degradation of poly(epsilon-caprolactone) film in phosphate buffer solution containing lipases

The enzymatic degradation of poly(epsilon-caprolactone) (PCL) films in phosphate buffer solution containing lipases has been studied by DSC, WAXD and SEM. Three lipases, pseudomonas lipase (PS), porcine pancreatic lipase (PP), and candida cylindracea lipase (AY), were used. The results showed that the degradation of PCL films in phosphate buffer solution containing PP or AY was very slow: no weight loss could be found within 1 week. However, PCL film could degrade rapidly and completely within 4 days in phosphate buffer solution containing PS lipase. (C) 1997 Elsevier Science Limited.

海州湾前三岛海域栉孔扇贝生态增养殖原理与关键技术

以海州湾前三岛周围海域为研究地点，开展了栉孔扇贝岛屿生态增养殖理论和关键技术研究。调查了海区的地理、水文、水化学环境以及饵料供应能力；现场测定了栉孔扇贝的滤水率，根据扇贝实际生长情况结合水动力学因子评估了该海域的养殖容量；监测了不同养殖模式情况下栉孔扇贝的存活、生长以及污损生物附着情况；利用免疫学指标揭示了各种养殖方式下栉孔扇贝的健康状态；研究了不同水温、扇贝规格对敌害生物捕食的影响；优化了该海域栉孔扇贝的养殖模式和关键技术。主要研究结果如下： 1．查明了前三岛海域理化环境、生物资源等现状。前三岛海域水质优良，生物资源丰富，虽然饵料浓度相对较低，但是该海域海流畅通，水交换条件好，较高的流速可以弥补饵料浓度的不足，适合开展栉孔扇贝增养殖。由于各项理化因子随着时间和水深的变化而发生变化，必须根据实际情况，对养殖模式等进行相应调整，才能获得更高经济和生态效益。 2．较为系统地研究了前三岛海域深水筏式养殖栉孔扇贝生理生态学特征，评估了养殖容量。周年监测了海域的环境因子和栉孔扇贝的生长情况，利用生物沉积法，现场研究了各时期扇贝的滤食作用。结果表明：该海域养殖栉孔扇贝在当年秋、冬季和次年春季生长迅速，夏季生长相对缓慢，周年平均软组织生长速度为11.29 mg/d，平均干贝壳生长速度为48.84 mg/d，扇贝能够于次年年初达到商品规格（6cm）。不同时期栉孔扇贝的滤水率之间差异显著，滤水率随水温的升高和扇贝规格的增大而增加。利用改进的Incze等（1981）的养殖容量模型，评估了该海域养殖容量，结果表明：在现有条件下，各时期沿着海流方向适养区域长度分别为：4.0，4.6，4.7，5.1，4.5和3.2 km，平均为4.35 km。 3．揭示了不同养殖水层栉孔扇贝存活、生长以及免疫指标特征。于2007年夏、秋高温季节监测了5个不同水层（2, 5, 10, 15, 与 20 m）筏式养殖栉孔扇贝的存活、生长以及免疫指标特征。研究表明各水层栉孔扇贝成活率差异显著，其中15 m（78.0%）和20 m（86.7%）成活率要明显高于2 m（62.9%），5 m（60.8%），和10 m（66.8%）；夏季（7~9月）各水层壳高生长速度有较大差异，其中10m （205.0 μm/d）与20 m（236.9 μm/d）要显著高于2，5，和15 m，而秋季（9~11月份）20m生长速度最低，5m水层（262.9 μm/d）要显著高于其他水层；不同水层扇贝软组织生长情况与壳的生长情况类似；扇贝血淋巴SOD活性随着水深的加深而增大，15 和 20 m 养殖的栉孔扇贝ACP活性要高于其他水层，这表明深水养殖栉孔扇贝健康状态要优于浅水层。 4．比较研究了筏式和底播两种养殖方式情况下栉孔扇贝的存活、生长以及免疫指标的周年变化。结果表明夏季栉孔扇贝的生长、免疫酶活性要低于其他季节，扇贝死亡也基本集中于夏季高温季节。除了2008年春季壳高以外，筏式养殖栉孔扇贝的生长、免疫酶活性都要高于底播养殖。实验结束时筏式养殖的成活率（54.6 ± 12.3 %）要显著地低于底播养殖（86.8 ± 3.5 %）。由此可见，在夏季高温季节采取底播养殖提高成活率，然后转为筏式养殖以提高生长速度，这样可以获得更高的产量。 5．研究了日本蟳和多棘海盘车对栉孔扇贝的捕食机制。现场研究表明，成年日本蟳可以捕食壳高小于5.0 cm的栉孔扇贝，捕食强度随着水温的升高而增大，而壳高大于5.9 cm的栉孔扇贝则可以免遭日本蟳的捕食；与栉孔扇贝相比，日本蟳更倾向于捕食贻贝；室内模拟研究表明水温低于10 ℃时，日本蟳对大规格扇贝的捕食作用不明显。相同温度条件下，室内实验日本蟳的捕食强度要低于现场，但其温度系数（Q10）差别不大。室内试验表明多棘海盘车对栉孔扇贝也有很强的捕食作用。提出了提高底播栉孔扇贝成活率的方法，即选择大规格的扇贝在水温较低的秋、冬季进行底播。