兰州鲇与鲇消化系统的形态学及组织学比较研究

为探究黄河濒危鱼类兰州鲇（Silurus lanzhouensis）消化系统的形态学和组织学结构特点,以鲇（Silurus asotus）为对照,对兰州鲇消化系统形态学和组织学进行了深入研究。结果表明:（1）兰州鲇与鲇的消化道和消化腺形态相似,具有肉食性鱼类的特征。兰州鲇消化道较短,有发达的“U”型胃,胃内皱褶明显,无幽门盲囊,肠道短且粗,可分为前肠、中肠和后肠三部分,前肠粗大,后肠较细。两种鲇属鱼类都有独立致密的肝脏和胰脏。（2）兰州鲇的比肠长显著大于鲇（P < 0.05）,比胃重、比肝胰脏重显著低于鲇（P < 0.05）,但二者的比肠重无显著性差异（P>0.05）。（3）兰州鲇胃的皱襞幅度小于鲇,且环肌层比兰州鲇薄。兰州鲇与鲇前肠的肠黏膜均形成了大量皱襞,肠黏膜、褶皱粗大,但鲇的褶皱分支较细密。兰州鲇与鲇的后肠与前肠相比,肠腔变小,褶皱数量明显减少,高度降低。黏膜层分布有杯状细胞和柱状细胞。兰州鲇与鲇的肝脏肝小叶间缺少结缔组织,分界不明显,而兰州鲇肝细胞的密度大于鲇。综上所述,兰州鲇与鲇的消化系统相似,均符合肉食性鱼类消化系统特征,结合消化生理等研究结果,表明兰州鲇的消化能力弱于鲇,这可能是在自然情况下兰州鲇的分布区域及适应性不及鲇的原因之一。     

动物特殊动力作用的研究进展

特殊动力作用（SDA）是指动物摄食过程中的代谢产热增加的现象,自上世纪初,一直受到相关领域专家的关注。近十年来该方面研究十分活跃。我们以南方鲇（Southern catfish／Silurus meridionalis）和鲇鱼（catfish／Silurus asotus）为实验对象,开展了大量相关研究。本文就我们的研究成果结合相关研究进行探讨,并指出了该方面研究将来可能的方向。     

促性腺激素释放激素类似物对长臀鮠脑垂体促性腺激素分泌的影响

采用离体灌流孵育技术和促性腺激素的放射免疫测定方法,对长臀鮠(Cranoglanis bouderius)脑垂体碎片促性腺激素的分泌进行了研究。结果表明：持续的促性腺激素释放激素类似物(GnRH-A)能显著刺激退化期的长臀鮠离体脑垂体碎片促性腺激素(GTH)的分泌,并且长臀鮠脑垂体碎片对持续的GnRH-A刺激未表现出脱敏性,该结果与胡子鲇和鲇鱼相似,而与金鱼和鲤科鱼类不同;重复脉冲GnRH-A刺激对长臀鮠脑垂体碎片GTH分泌具有促进作用,而且存在剂量依存关系,与鲇鱼和鲤科鱼类相类似。上述结果表明在长臀鮠的人工繁殖中可以用持续高浓度GnRH-A刺激对长臀鮠进行催熟和催产。     

南方鲇免疫球蛋白单克隆抗体的制备及特性

采用PEG沉淀结合Sepharose-4B柱层析法分离纯化了健康非免疫状态下南方鲇血清免疫球蛋白,在SDS-PAGE电泳条件下血清免疫球蛋白重链和轻链的分子量分别约为77 kD和27 kD。应用杂交瘤单克隆抗体技术制备了4个南方鲇免疫球蛋白特异性的单克隆抗体细胞株,并对这些单克隆抗体的特性进行了分析。经抗体亚级份测定,其中IgG1有2株,IgG2a有1株,IgG2b有1株;抗体滴度为104—106,有三株单抗具有Western-blot反应特性,识别南方鲇免疫球蛋白的重链。4株单抗都能特异地识别南方鲇、鲇的免疫球蛋白,而与鲫、草鱼、罗非鱼、斑点叉尾、光泽黄颡鱼血清以及水产动物常见病原菌如气单胞菌、爱德华氏菌、弧菌、柱状屈桡杆菌、沙门氏菌及大肠杆菌等无任何交叉反应。单克隆抗体F4-A12对纯化的南方鲇免疫球蛋白的检测灵敏度为31 ng。实验结果证明这些单抗具有高度特异、高度灵敏等特点,可用于南方鲇免疫球蛋白的结构分析、免疫应答水平监测和病原诊断,具有广阔的应用前景。     

A unique epidermal mucus lectin identified from catfish (Silurus asotus): first evidence of intelectin in fish skin slime

The present study reports a new type of skin mucus lectin found in catfish Silurus asotus. The lectin exhibited calcium-dependent mannose-binding activity. When mannose eluate from chromatography with mannose-conjugated agarose was analysed by SDS-PAGE, the lectin appeared as a single 35-kDa band. Gel filtration showed that the lectin forms monomers and dimers. A 1216-bp cDNA sequence obtained by RACE-PCR from the skin encoded a 308 amino acid secretory protein with homology to mammalian and fish intelectins. RT-PCR demonstrated that the lectin gene was expressed in the gill, kidney and skin. Subsequent sequencing revealed the presence of an isoform in the gills. Antiserum detected the intelectin protein in club cells in the skin and gill, renal tubules and blood plasma. Although intelectin gene expression was not induced by in vivo bacterial stimulation, the intelectin showed agglutination activity against the pathogenic bacterium Aeromonas salmonicida, suggesting that the lectin plays an important role in self-defence against bacteria in the skin surface of the catfish. These findings represent one of the few examples of characterization and functional analysis of a fish intelectin protein.     

多马胺能药物对鲇鱼促性腺激素（GtH）分泌活动的影响

以珠江流域鲇鱼（silurus asotus)为实验材料,研究了多巴胺（DA）能药物（DA及其D－2型受体拮抗物 ,DOM）对鲇鱼促性腺激素（GtH)释放的影响,结果表明,在性腺发育的各个时期,单独注射DOM（5ug/g)均不能显著提高鲇鱼血液基础GtH水平,当DOM与LHRH－A联合注射时能显著增强LHRH－A刺激GtH释放的作用;DA只能抑制GnRH诱导的GtH释放,对基础GtH释放无抑制作用,这种生殖内分泌调节方式与鲇形目的革胡子鲇（Clarias gariepinus)和大鳍Hu（Mystus macropterus)相似,而与鲤形目的鲁科（Cyrpindiae)鱼类不同。     

Spawning and season affect lipid content and fatty acid composition of ovary and liver in Japanese catfish (Silurus asotus)

The influences of spawning and season on lipid content, lipid classes, and fatty acid composition were assessed in ovary and liver of wild and cultured Japanese catfish (Silurus asotus). The lipid content (7.3+/-1.6 g/100 g wet wt.) of ovary from wild catfish at spawning was higher than that at post-spawn. However, no influence of spawning on the lipid content of liver was observed. Docosahexaenoic acid [DHA, C22:6(n-3)] in ovary lipids was 12.3+/-0.5% of total fatty acids. The percentage of n-7 monounsaturated fatty acids in triacylglycerol from the ovary and liver in the spawning season was high. Percentages of C22:6(n-3) in phosphatidylcholine and phosphatidylethanolamine from ovary were higher during spawning than after spawning. No significant differences were observed in the lipid content of ovary and liver from cultured catfish between seasons (summer vs. winter). Content of arachidonic acid (C20:4n-6) in ovary and liver from cultured catfish was higher in summer than in winter. There were differences in lipid classes of ovary and liver by spawning and season. These results suggest that the lipid metabolism in Japanese catfish is greatly influenced by spawning and season.     

Dietary and seasonal effects on the dorsal meat lipid composition of Japanese (Silurus asotus) and Thai catfish (Clarias macrocephalus and hybrid Clarias macrocephalus and Clarias galipinus)

The effects of dietary lipids and seasonal variation on the lipids of wild and cultured catfish (Japanese catfish, Silurus asotus; Thai catfish, Clarias macrocephalus and hybrid Clarias macrocephalus x Clarias galipinus) were determined by analysis of the lipid content and fatty acid composition of their dorsal meat. The predominant fatty acids of dorsal meat were 16:0, 18:1n-9, 18:2n-6, 20:4n-6 (arachidonic acid, AA), and 22:6n-3 (docosahexaenoic acid, DHA). The DHA content in the diet of Japanese catfish was higher than that in the diet of Thai catfish, and this was reflected in the dorsal meat of the Japanese catfish, which had a remarkably high percentage of DHA compared with the meat of the Thai catfish. Cultured Japanese catfish had a higher percentage of 18:2n-6 than Thai fish and a lower percentage of AA in winter than in summer season. There were also seasonal variations in the percentage of n-6 fatty acids in Japanese catfish. In summer, the fatty acid composition of the cultured Japanese catfish was similar to that of the wild catfish. These fatty acid changes in the lipid classes, triacylglycerol, phosphatidylcholine and phosphatidylethanolamine were similar to those observed for total lipids. These results indicate that the percentage of DHA in the dorsal meat of catfish is influenced by dietary fatty acid, and it may be that it can be increased in cultivated fish by administering a diet containing a large amount of DHA.     

The complete mitochondrial genome of the spotted steed, Hemibarbus maculatus (Teleostei, Cypriniformes)

The complete mitogenome sequence of the spotted steed (Hemibarbus maculatus) was determined using long PCR reactions. The genome is 16,611 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The gene order and composition of H. maculatus was similar to that of most other vertebrates. The base composition of H-strand in descending order is A (29.16%), C (27.41%), T (25.93%), and G (17.50%), with an AT content of 55.09%. The Kimura two-parameter distances between mitogenome sequences of H. maculatus and Hemibarbus labeo, Hemibarbus barbus, Hemibarbus longirostris, Hemibarbus mylodon were 2.09%, 2.35%, 12.77%, and 13.92%, respectively. The phylogenetic relationships among the five Hemibarbus species based on the whole mitogenome sequence data were (((H. barbus, H. labeo), H. maculatus), (H. longirostris, H. mylodon)).     

Mitochondrial genome of Onychostoma lini (Teleostei, Cypriniformes)

The complete mitogenome sequence of a vulnerable species Onychostoma lini was determined using polymerase chain reaction and directly sequenced with primer walking method. The complete mitogenome was 16,595?bp in length, containing 37 genes of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region (D-loop). The gene order and composition of O. lini was similar to most other fishes. The descending order of the base composition on heavy strand was 31.6% A, 27.9% C, 24.6% T, and 15.9% G, with a relatively lower level of G and a slight AT bias of 56.2%. The codon usage followed the typical vertebrate mitochondrial pattern (ATG or GTG for start codon and TAA or TAG for stop codon). The complete mitogenome sequence of O. lini provides fundamental data for further conversation genetics and captive breeding studies on this species.     

The complete mitochondrial genome of sable, Martes zibellina

The complete mitogenome sequence of the Sable (NC_011579) was determined using long PCR (Polymerase Chain Reaction). The genome was 16,523?bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region. The gene composition and order of which was similar to most other mammals. The overall base composition of the heavy strand in descending order is A (32.0%), C (27. 6%), T (25.8%) and G (14.7%). The base compositions present clearly the A-C skew, which is most obviously in the control region and protein-coding genes. The extended termination-associated sequence domain, the central conserved domain, and the conserved sequence block domain are defined in the mitochondrial genome control region of Sable. This mitogenome sequence data would play an important role in phylogenetics and systematics of Martes zibellina.     

Complete mitochondrial genome of Oxuderces dentatus (Perciformes, Gobioidei)

The complete mitochondrial genome (mitogenome) of Oxuderces dentatus was determined first. The genome was 17,116?bp in length and consisted of 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, and 2 main non-coding regions [the control region (CR) and the origin of the light strand replication], the gene composition and order of which was similar to most other vertebrates. The overall base composition of the heavy strand was T 27.9%, C 26.8%, A 30.2%, and G 15.1%, with a slight A+T bias of 58.1%. In addition to the discrete and conserved sequence blocks, unusual long tandem repeat unit (three 150-bp tandem repeat units and an incomplete copy of 146?bp) was also detected within CR. This mitogenome sequence data would play an important role in population genetics and phylogenetic analysis of the Gobioidei.     

兰州鲇与鲇、黄河鲤肌肉品质比较研究

为深入探究兰州鲇(Silurus lanzhouensis)肌肉品质特性, 对黄河中兰州鲇、鲇(Silurus asotus)和黄河鲤(Cyrinus carpio)肌肉品质指标进行了测定。结果表明: 兰州鲇肌肉的pH、滴水损失、熟肉率、胶原蛋白、肌原纤维耐折力、黏附性、内聚性、胶黏性、咀嚼性、弹性和回复性等指标与鲇差异不显著(P>0.05), 失水率、肌纤维直径和硬度在二者间差异显著(P<0.05); 兰州鲇肌肉的pH、肌纤维直径、硬度、黏附性、回复性、胶黏性和咀嚼性与黄河鲤差异不显著(P>0.05), 肌肉滴水损失、熟肉率、失水率、胶原蛋白、肌原纤维耐折力、内聚性和弹性在二者间差异显著(P<0.05)。相关性分析表明, 兰州鲇肌肉咀嚼性与硬度呈极正相关, 其关系式为: y=0.3651x+25.339(R=0.97); 回复性与内聚性呈极正相关, 其关系式为: y=0.6279x-0.0929(R=0.91); 胶黏性与硬度呈极正相关, 其关系式为: y=2.4104x-41.155(R=0.97)。对兰州鲇7个质构指标进行了主成分分析, 提取出3个主成分, 累计方差贡献率为96.08%, 其中硬度是影响兰州鲇质构特性的主要因素。黄河中兰州鲇和鲇作为鲇属鱼类中形态十分相似的两个物种, 在肌肉品质特性上既有很大的相似性, 又有一定的不同, 这可能与这两种鱼种质特性的异同有关。     

草鱼GH单克隆抗体对9种硬骨鱼的免疫细胞化学定位

研究结果表明：１）鳜和鲇的胰岛中有大量的ＧＨ免疫活性内分泌细胞存在;８种有胃硬骨鱼的消化道中均未见到阳性特异性反应。２）草鱼的中腺,前腺垂体中均发现有ＧＨ和Ｓｏｍ两种免疫活性肉发泌细胞存在。     

The complete mitochondrial genome of Chinese rare minnow, Gobiocypris rarus (Teleostei: Cypriniformes)

The Chinese rare minnow, Gobiocypris rarus, which is endemic to China, is an attractive aquatic laboratory animal in China. In the present study, the complete mitogenome sequence of G. rarus has been determined using long polymerase chain reaction (PCR) method. It was 16,601 bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region, the gene composition and order of which are similar to most other vertebrates. Except for eight tRNA and ND6 genes, all other mitochondrial genes are encoded on the heavy strand. The overall base composition of the heavy strand is 29.5% A, 27.6% T, 25.7% C, and 17.2% G, with a slight AT bias of 57.1%. There are 10 regions of gene overlap totaling 27 bp and 13 intergenic spacer regions totaling 63 bp. The mitogenome sequence of G. rarus could contribute to a better solution of its phylogenetic position within cyprinid fishes based on the whole mitogenomic data.     

Complete mitochondrial genome of Chilo suppressalis (Walker) (Lepidoptera: Crambidae)

The complete sequence of the mitochondrial genome (mitogenome) of the rice stem borer Chilo suppressalis (Walker) (Lepidoptera: Crambidae) was determined to be 15,465 bp. It contains 13 protein-coding genes (PCGs), 22 tRNA genes, the large and small rRNA genes, and an A+T-rich region. The nucleotide composition of the mitogenome of C. suppressalis is highly A+T biased, accounting for 79.70% in whole mitogenome, 77.74% in PCGs, 84.70% in tRNAs, 81.20% in rRNAs and 94.19% in A+T-rich region, respectively. The PCGs have typical ATN start codons, except for cox1, which contains the unusual CGA. The C. suppressalis A+T-rich region contains a conserved structure combining the motif ATAGA and a 19-bp poly-T stretch, but absence of the 9-bp poly-A element upstream trnM.     

四个不同地理鲇群体肌肉营养组成的比较分析

为了丰富黄河、松花江和大洋河鲇的肌肉营养数据, 试验采用国家标准方法对4个自然河段鲇群体(黄河白银段BY、黄河郑州段ZZ、松花江哈尔滨段HEB和大洋河东港段DG)背部肌肉的营养组成进行测定。结果表明, BY群体粗蛋白显著(P0.05)高于ZZ和DG两群体, BY群体粗脂肪显著(P0.05)高于ZZ、DG和HEB三群体。四群体脂肪酸组成以不饱和脂肪酸为主, 单不饱和脂肪酸中油酸含量最高, BY群体油酸含量显著(P0.05)高于ZZ、DG和HEB三群体, BY群体EPA+DHA含量最低, 和ZZ、DG和HEB三群体有显著(P0.05)差异。四群体氨基酸组成均以谷氨酸含量最高。除缬氨酸和异亮氨酸外, 四群体其余氨基酸评分(AAS)均接近或大于1; 四群体各氨基酸的化学评分(CS)均大于0.5。缬氨酸为第一限制性氨基酸, 异亮氨酸为第二限制性氨基酸。必需氨基酸指数(EAAI), HEB群体最高, DG群体最低。该结果说明, BY群体与ZZ、DG和HEB三群体营养价值差别大, ZZ、DG和HEB三群体间营养价值接近。四群体的营养差异可能由不同地理环境导致。     

社鼠（Niviventer confucianus）线粒体基因组全序列分析

社鼠（Niviventer confucianus）属于啮齿目（Rodentia）、鼠科（Muridae）、白腹鼠属（Niviventer）,关于该物种的分子系统学研究极少。为获取社鼠线粒体基因组全序列,提取其基因组总DNA,参照近缘物种线粒体基因组全序列设计34对特异性引物,利用PCR扩增全部片段后进行测序,之后对其基因组组成及结构特点进行了初步分析。结果表明,社鼠线粒体基因组全序列长16 281 bp（GenBank收录号：KJ152220）,包含22个tRNA基因、13个蛋白质编码基因、2个rRNA基因和1个非编码控制区;基因组核苷酸组成为34.0%A、28.6%T、24.9%C、12.5%G。将所得序列与社鼠近缘物种（川西白腹鼠、小家鼠、褐家鼠）的线粒体全基因组进行比较,结果显示,四个物种的线粒体基因组虽然在基因组大小、部分tRNA二级结构、部分蛋白质编码基因的起始或终止密码子及控制区长度和碱基组成上有差异,但基因组结构和序列特征方面都具有较高的相似性。四个物种线粒体全基因组间的遗传距离显示,社鼠与川西白腹鼠距离最近,而与小家鼠距离最远。该研究为利用线粒体全基因组信息进行啮齿类分子系统学研究提供了有价值的资料。     

Complete mitochondrial genome of Trypauchen vagina (Perciformes, Gobioidei)

The complete mitochondrial genome of Trypauchen vagina was determined first. The genome is 16,686 bp in length and consists of 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, and 2 main non-coding regions [the control region (CR) and the origin of the light strand replication], the gene composition and order of which was similar to most other vertebrates. The overall base composition of T. vagina is T 27.6%, C 27.6%, A 29.5%, and G 15.3%, with a slight A+T bias of 57.1%. In addition to the discrete and conserved sequence blocks, an incomplete tandem repeat unit is detected within the CR. This mitogenome sequence data would play an important role in population genetics and phylogenetic analysis of the Gobioidei.     

Complete mitochondrial genome sequence of the Indian pipistrelle Pipistrellus coromandra (Vespertilioninae)

We characterized the complete mitogenome of Pipistrellus coromandra (Indian pipistrelle) for comparative analysis of mitogenomes and for resolving the phylogenetic relationship of four tribes in the subfamily Vespertilioninae. The mitogenome size of P. coromandra was 17,153?bp, with a control region and a typical set of 37 mitochondrial genes. The nucleotide composition of the P. coromandra mitogenome showed an AT bias with a nucleotide composition of 33.5% A, 30.7% T, 13.3% G, and 22.5% C. The mitochondrial protein-coding genes in P. coromandra use the standard start codon (ATN), two stop codons (TAA and AGA), and two incomplete stop codons (TA- and T--). The intertribal relationship of four tribes was highly resolved from the phylogenetic analysis of mitogenome sequences.