Altered glutathione status in atlantic croaker (Micropogonias undulatus) tissues exposed to lead

Metals which induce the synthesis of metallothioneins, such as cadmium and mercury, also elevate glutathione (GSH) concentrations in fish tissues.^1,2 To determine whether metals which do not stimulate metallothionein synthesis increase GSH levels, the GSH status of Atlantic croaker tissues was examined after oral administration of lead. Lead significantly increased GSH levels in the intestine and liver, but not in kidney or brain tissues. Lead was not bound to GSH and the increase in GSH did not appear to be linked to lead accumulation in these tissues. Investigations of hepatic GSH synthesis and turnover in vitro using a radiolabelled amino acid precursor, C¹⁴ glycine, showed that the elevation of GSH was due to an increase in GSH synthesis rather than decreased utilization of GSH. These studies suggest that the interactions between GSH and lead are indirect and involve a stimulatory effect of the metal on the activity of the enzymes for GSH synthesis.     

Distribution of whitemouth croaker (Micropogonias furnieri, Desmarest 1823) larvae in the Río de la Plata estuarine front

Whitemouth croaker (Micropogonias furnieri) larvae obtained and hydrographic data collected in the Rio de la Plata estuary (35°S–56°W) between 1987 and 2000 were used to explore the early life stages spatial and temporal distribution patterns and their relation to oceanographic features. The spatial distribution, restricted to a band in the inner part of the estuary, coincided with the bottom salinity front and the maximum turbidity zone (MTZ, turbidity front). Larvae were present during the warmest months (October through May) within a range of 14–24.5 °C temperature and 0.9–33 salinity. A vertically stratified sampling performed in the region where the largest abundance was found (December 2005 and March 2006) was used to test the hypothesis that larvae retention occurs in the bottom salinity front.The vertically stratified sampling showed larvae throughout the water column with high predominance in the river–estuary transition zone. A positive correlation between abundance and the bottom salinity horizontal gradient was found. The size analysis showed that the largest individuals (>10 mm SL), probably undergoing the settlement process, inhabited near the bottom and that the smallest (<10 mm SL) were present in the whole water column. Length distribution along the front showed no trend.Results support the estuarine retention hypothesis of previous studies on whitemouth croaker gravid females, eggs distribution and outcomes from a numerical simulation model. Retention in the salinity front/MTZ would allow larvae to benefit from food accumulation in the region, the high turbidity level provide shelter against predators and retention in the estuary secure closeness to the main nursery ground.     

波纹唇鱼骨骼系统特征的研究

为揭示波纹唇鱼(Cheilinus undulatus)骨骼形态特征,作者采用X射线成像法对波纹唇鱼骨骼进行相关研究。研究发现,波纹唇鱼下口位具牙齿,颌骨密度较大,舌颌骨下端具臼齿状结构;脊柱由10枚躯椎和13枚尾椎构成,第1~10枚脊椎骨连接10对腹肋,第6~9枚脊椎骨具椎体横突,第11~22枚脊椎连接12枚脉棘,第1~21枚脊椎骨连接21枚髓棘,第22枚脊椎上脉棘不明显;第2~8枚脊椎可观察到背肋;4块尾上骨(含1块髓棘)和5块尾下骨(含两块脉棘);肩带位于第1~3枚脊椎下方;腰带位于第5枚脊椎骨下方腹面;背鳍位于第5~21枚脊椎骨上方;臀鳍位于第13~19枚脊椎骨下方腹面。研究结果表明,X射线法可以清晰观察波纹唇鱼骨骼,实现无伤化研究珍稀鱼类;为适应在珊瑚礁中穿梭、捕食和增加消化能力,波纹唇鱼具有独特的骨骼构造。波纹唇鱼骨骼的研究丰富了南海珊瑚礁鱼类的研究基础,为其分类及演化提供参考。     

波纹唇鱼微卫星分子标记的筛选及适用性分析

采用磁珠富集法及利用生物素标记的(CA)15寡核苷酸探针从波纹唇鱼(Cheilinus undulatus)基因组DNA Bsp143Ⅰ酶切位点的400~1000 bp片段中筛选CA/GT微卫星位点。洗脱的杂交片段克隆到PMD18-T载体上构建富集微卫星基因组文库后,通过PCR筛选出阳性克隆进行测序。在120条序列中有88条序列包含有重复次数不少于5次的微卫星位点,阳性序列比例达到73.33%。其中完美型(perfect)类型微卫星最多的重复次数为26次。在88条非冗长序列中,共有28条(31.82%)微卫星重复序列两端有侧翼序列能够进行引物设计。用波纹唇鱼3个个体的混合基因进行引物筛选,其中的24对具有清晰的扩增条带。将筛选的24对引物对波纹唇鱼1个群体的39个个体进行遗传多样性分析,其中4对引物扩增产物为单态,20对扩增产物呈多态性;20对扩增多态的引物在39个个体中扩增出等位基因数为2~12,平均有效等位基因数为3.5。该波纹唇鱼群体的PIC、Ho、He的平均值分别为0.0782、0.8513、0.5667。这20个微卫星位点适于波纹唇鱼群体遗传结构的研究分析。     

大黄鱼EBI3基因的克隆与表达分析

通过克隆大黄鱼(Larimichthys crocea)的EBI3(Epstein-Barr virus-induced gene 3)基因并对其进行了序列分析.大黄鱼EBI3(Lyc EBI3)基因开放阅读框长747bp,编码248个氨基酸,存在1个信号肽序列和2个FN3结构域(37~130,145~230).多序列比对发现Lyc EBI3分子与其他已知EBI3氨基酸水平一致性为27.68%~57.53%.Real-time PCR结果表明,Lyc EBI3基因在脾脏和血液中表达量最高,且溶藻弧菌(Vibrio alginolyticus)刺激后,大黄鱼头肾和脾脏中Lyc EBI3基因的转录水平会显著升高,说明Lyc EBI3基因可能参与了抑制由细菌引起的炎症反应.     

大黄鱼( Larimichthys crocea ) CRFB13 基因的克隆与表达分析

IFN-γ是哺乳动物的一个关键免疫调节因子,通过特异性地结合IFN-γ受体1(IFNGR1)和IFN-γ受体2(IFNGR2)组成的异源四聚受体复合物,来发挥其生物学功能.目前,在鱼类中已经克隆出IFNGR1基因的2个亚型:细胞因子受体家族B 13(CRFB13)和细胞因子受体家族B17(CRFB17).本研究从大黄鱼(Larimichthys crocea)中克隆得到了一个CRFB13基因(Lyc CRFB13),其开放阅读框全长1 158个核苷酸,编码由385个氨基酸组成的1个蛋白.Lyc CRFB13蛋白具有典型的II型细胞因子受体特征,包括1个信号肽、1个胞外的FN III-like结构域,1个单次跨膜结构域,以及胞内的JAK1和STAT1结合位点.氨基酸序列分析表明鱼类的CRFB13都具有JAK1和STAT1结合位点.系统进化分析表明鱼类的2种IFNGR1,CRFB13和CRFB17形成2个独立的分支,Lyc CRFB13和鱼类的CRFB13聚在一起,与雀鲷(Stegastes partitus)CRFB13的亲缘关系最近.组织分布显示Lyc CRFB13为组成型表达,在大黄鱼鳃中的表达量最高,而在小肠中的表达量最低.Poly(I:C)刺激后,大黄鱼鳃和头肾中CRFB13的mRNA转录水平都显著升高.此外,poly(I:C)和LPS还能够诱导大黄鱼头肾白细胞中Lyc CRFB13的表达,这些结果表明Lyc CRFB13可能在大黄鱼抗病毒、抗细菌免疫反应中发挥重要作用.     

Antagonistic effects of xenobiotics on steroid-induced final maturation of Atlantic croaker oocytes in vitro

The antagonistic effects of Kepone (chlordecone) and o,p'-DDD on maturation-inducing steroid (17α,20β,21-trihydroxy-4-pregnen-3-one, 20β-S) induced final maturation of Atlantic croaker (Micropogonias undulatus). Oocytes were investigated in an in vitro germinal vesicle breakdown (GVBD) bioassay. Exposure to Kepone or o,p'-DDD (100 nM-100 μM) prevented the majority of the oocytes from completing GVBD in response to 20β-S; many of them were arrested at the lipid coalescence or germinal vesicle migration stages when exposed to high xenobiotic concentrations (100 μM). In addition, clearing of the ooplasm, oil droplet formation and hydration were incomplete in xenobiotic-exposed oocytes that underwent GVBD. The xenobiotics inhibited GVBD in a concentration-dependent manner. One minute exposure to either of the xenobiotics was sufficient to block GVBD. Washing the follicle-enclosed oocytes after xenobiotic exposure restored their ability to undergo GVBD in response to 20β-S. These results suggest that o,p'-DDD and Kepone exert antagonistic effects on 20β-S action, possibly by competing for the ovarian 20β-S membrane receptor.     

养殖波纹唇鱼雌鱼形态性状对体质量的相关性及通径分析

为确定波纹唇鱼雌性亲鱼选育标准,了解形态性状与体质量的关系,筛选出主要生长性状。本研究开展了波纹唇鱼雌性亲鱼形态性状相关性分析、通径分析和回归分析。结果显示:波纹唇鱼雌性亲鱼体质量变异系数最大;各性状之间除头长X₃与胸鳍长X₆,X₃与躯干长X₁₁和眼径X₅与腹鳍长X₇相关性不显著,其余各性状间显著相关(P<0.05)或极显著(P<0.01)相关;筛选出4个与体质量相关性最大的形态性状体长X₂、体高X₄、臀鳍长X₈、尾长X₁₂;直接作用最大的形态性状是X₂,间接作用最大的形态性状是X₄;直接决定系数最大的是形态性状X₂, X₂-X₄的间接决定系数最大;构建多元回归方程为Y=-3.402+0.016X₂+0.453X₄     

渤海小黄鱼生殖力及其变化

根据2004年5月在渤海进行的拖网调查资料,分析了小黄鱼(Pseudosciaenapolyatics)在经过近半世纪的捕捞后的生殖群体生殖力及其与体长、纯体质量的关系,并对小黄鱼生殖力的变化作了比较。结果表明,小黄鱼的个体绝对生殖力为14729粒±1360粒;个体绝对生殖力与叉长、纯体质量的关系变化较大;与1964年历史资料相比,相同体长组小黄鱼的个体绝对生殖力F和相对生殖力FL都显著增大(P<0.01)。小黄鱼的生殖力增加可能是小黄鱼在长期捕捞等外部环境影响下的遗传进化以及对其生存环境的适应性响应。     

中国近海大黄鱼和日本带鱼群体数量变动及其资源保护措施探讨

作者根据长期调查研究,分析了大黄鱼(Larimichthys crocea)和日本带鱼(Trichiurus japonicus)群体数量变动的因果关系,并提出了加强我国海洋渔业资源科学监管的建议:(1)正确划分大黄鱼和带鱼地理种群及其产卵群体,为资源繁殖保护提供参考依据;(2)修订若干《渔业法》条款,重新审定《官井洋大黄鱼繁殖保护区管理规定》;(3)充分合理开发利用闽东渔场近海岛屿周边海域,并且采用抗风浪升降式圆柱形深水养殖网箱养殖大黄鱼;建立内湾性官井洋大黄鱼海洋牧场渔业基地,并新建中国著名舟山渔场大黄鱼繁殖保护区;(4)继续加强大黄鱼原种场建设,大力开展大黄鱼良种选育研究,每年提供大批量野生大黄鱼人工培育的原种子一代幼鱼进行增殖放流;(5)巩固和扩大伏季休渔效果,全年禁止违法而严重损害带鱼幼鱼资源的各种张网作业;(6)以法治渔,加快制定符合于我国实情的海洋渔业科学监管的有效措施.     

大黄鱼精液的高效超低温保存

采用2 mL的冷存管和程序降温仪高效超低温保存大黄鱼(Pseudosciaena croce)精液。分析比较了5种不同浓度抗冻剂(二甲基亚砜、乙二醇、丙二醇和甘油和甲醇)、3种降温速率(10,20和30℃/min)和2种解冻温度(28℃和43℃)对大黄鱼精液超低温保存效果的影响。实验结果表明,采用Hanks’作为稀释液,10%～20%甘油或10%DMSO作为抗冻剂,20℃/min的降温速率对精液进行超低温保存43℃水浴解冻,冻精激活后获得理想的运动率(76.6%±11.4%～80.0%±12.6%),而且对10%甘油保存的冻精进行人工授精实验获得了与新鲜精液相似的受精率和孵化率。     

波纹唇鱼mtDNA D-loop 序列变异分析

为研究波纹唇鱼(Cheilinus undulatus)线粒体D-loop 序列遗传多样性, 作者采用聚合酶链式反应和克隆技术对海波纹唇鱼群体(n=25)的mtDNA D-loop 序列进行克隆和测序, 获得长度大约为1 400 bp的产物。用ClustalX 软件进行排序比较, 将结果导入MEGA5.0, 结果显示出在这25 尾个体中, 共检测出66 个变异位点, 包括0 个碱基缺失, 4 个碱基插入, 59 转换位点, 2 颠换位点及1 个转换和颠换同时存在的位点。并用MEGA5.0 软件构建该群25 尾个体的NJ 和UPGMA 系统树。由DNASP 软件计算出该波纹唇鱼群体的多态位点数(S)为62, 核苷酸多样性(P_i)为0.00606, 平均核苷酸差异数为6.907。结果表明波纹唇鱼群体的mtDNA-loop 基因个体差异程度不明显。     

Metabolism and organ distribution of nonylphenol in Atlantic salmon (Salmo salar)

Nonylphenol (NP) is a breakdown product of alkylphenol polyethoxylates (APEs), an important class of non-ionic surfactants that are widely used in many detergent formulations and plastic products for industrial and domestic use. A complex microbial degradation pattern, characterized by the formation of several metabolic products that are more toxic than the parent compound, has been established for APEs. We have studied the in vivo metabolism and organ distribution of NP in juvenile salmon. Fish were exposed to a single oral dose of [³H]-4-n-NP (1295 KBq, 25 μg) and sampled at 24, 48 and 72 h after exposure. Metabolites were separated by radio-high-performance liquid chromatography and tentatively identified by co-chromatography with standards characterized by mass spectrometry. Our results show that 4-n-NP was mainly metabolized in vivo to its corresponding glucuronide conjugate and to a lesser extent to various hydroxylated and oxidated compounds. Biliary excretion at 72 h after dosing amounted to 2.83±0.75% of the administered radioactivity. Kinetic analysis shows that NP-glucuronide accounted for 83, 95 and 81% of total radioactivity in the HPLC-injected bile sample at 24, 48 and 72 h, respectively, after exposure. The half-life of residues in carcass and muscle was between 24 and 48 h after exposure.     

Genetic variation of the small yellow croaker (Larimichthys polyactis) inferred from mitochondrial DNA provides novel insight into the fluctuation of resources

The small yellow croaker (Larimichthys polyactis) belongs to the family Sciaenidae, which is an offshore warm fish species and widely distributed in the western Pacific. In this study, the variation of genetic diversity and genetic differentiation among L. polyactis populations was analyzed by mitochondrial DNA control region. A total of 110 polymorphic sites were checked, which defined 134 haplotypes. High level of haplotype diversity (h=0.993±0.002) was detected in the examined range. Population genetic structure analyse (analysis of molecular variance, F_st) showed there were high gene flow among L. polyactis populations. The result showed that there were relatively high genetic diversity and low genetic differentiation among the Yellow Sea and the East China Sea populations, which can be attributed to diverse habitats, wide distribution range and high mutation rate of control region. Using phylogenetic methods, coalescent analyses (neutrality tests, mismatch distribution analysis, Bayesian skyline analyses) and molecular dating interpreted in conjunction with paleoclimatic and physiographic evidence, we inferred that the genetic make-up of extant populations of L. polyactis was shaped by Pleistocene environmental impacts on the historical demography of this species. Besides, relatively constant genetic diversity and larger effective population size were detected in recent L. polyactis population. The result showed that the fishing policy certainly, such as the summer closed fishing, played a role in protecting resources of L. polyactis. This study can offer a wealth of biological novelties which indicates genetic structure of L. polyactis population and provides the foundation for resources protection and policy setting.     

大黄鱼选育群体与普通养殖群体部分免疫指标的比较

以本课题组选育的“闽优1 号”及未经选育的普通大黄鱼(Larimichthys crocea)养殖群体为研究对象, 比较了两者的白细胞吞噬活性、血清溶菌酶活性、杀菌活力、白蛋白及免疫球蛋白含量、血清及血细胞超氧化物歧化酶(SOD)活性等免疫指标的差异。结果表明: 选育的“闽优1 号”大黄鱼血清溶菌酶和血细胞SOD 活力显著高于对照组(P<0.05), 而血清中的免疫球蛋白含量低于普通养殖群体。在病原菌攻毒后8 d 内, 选育群体累积死亡率显著低于非选育群体, 提示非特异性免疫在大黄鱼抗病免疫的早期阶段可能起着重要作用。     

大黄鱼脊椎骨及其早期发育研究

为完善大黄鱼(Larimichthys crocea)的骨骼生物学特性和以脊椎骨为数量性状的新品种选育提供理论依据,作者统计了大黄鱼成鱼脊椎骨骨节数量性状,并采用软骨—硬骨双染色方法对其成体及5～40日龄仔稚幼鱼脊椎骨骨节的发育过程进行观察,并对骨节数量和生长进行统计分析.结果表明:统计成体48尾中,骨节数主要是26,...     

中国沿海小黄鱼种群动力学及其空间异质性研究

小黄鱼是我国近海四种最重要的经济鱼类之一,在过去的几十年中小黄鱼种群及其两个地理亚种群经历了巨大的变化。小黄鱼的种群动力学研究,对于维持这一重要渔业的可持续管理是至关重要的。目前仅有的两个小黄鱼种群动力学模型只涵盖了较短的时间,且没有关注其空间差异。本文研究了1968年至2015年间黄渤海和东海小黄鱼的种群动力学模型,包含和不包含空间分层结构的两种贝叶斯模型被用于分析其种群动力学的大尺度空间异质性。本文分析了不同的假设,来研究小黄鱼种群动力学潜在的变化趋势。研究结果表明小黄鱼种群动力学特征具有明显的时间和空间变化。种群的增长速度从20世纪八十年代开始增加,而可捕系数从1981年到2015年增加了两倍多。与黄渤海亚种群相比,东海的小黄鱼亚种群生长速度更快,遭受的捕捞压力也更大。基于最大可持续产量MSY的参考点表明,无论是整个小黄鱼种群还是两个亚种群,近年来都有非常高的过度捕捞风险。因此我国小黄鱼的渔业管理急需更加保守的管理策略,同时考虑其地域差异。本文所用的方法可以应用于其他种类的资源评估和渔业管理,尤其是具有空间异质性和数据有限的种类。     

Comparative studies on some genetic characteristics among four large yellow croaker (Pseudosciaena crocea) populations

The genetic structure was compared among four large yellow croaker (Pseudosciaena crocea) populations, an important aquaculture species in China. RAPD and ISSR results show that the genetic distances between domestic stocks and their wild counterparts are significantly larger than those between the three wild stocks. The sequence of mtDNA cyt b shows that the three wild populations share the same sequence, with differences in the four bases from the cultured stock: two transitions [57(C-T), 291(G-A)] and two transversions [66(C-G),223(A-C)]. Cluster analysis reveals that the domestic stock has diverged from its parental wild stock [Min—Yuedong (Fujian Province—eastern Guangdong Province, China) stock]. Results demonstrate that 20 a of domestication of the Pseudosciaena crocea stock has resulted in significant genetic changes.