南沙群岛重点岛礁潟湖微型浮游动物的群落结构与摄食     

赵常升  刘永  肖雅元  谢志超  王学锋  李纯厚 《水产学报》2022,46(6):973-983

潟湖是岛礁生物多样性演变的重要环境场,在岛礁水生态系统的物质循环和能量流动中发挥重要作用,而微型浮游动物的生态功能研究是解析南沙群岛岛礁水域潟湖生态系统初级生产力组成、流向、能量流动效率的重要研究内容之一。实验通过对南沙群岛重点岛礁渚碧礁、美济礁与永暑礁潟湖表层水域中微型浮游动物与生态环境调查,研究了其群落结构及其与环境因子的关系,并通过稀释培养实验研究了微型浮游动物的摄食压力。结果显示,调查水域共发现微型浮游动物20种,总丰度的范围为320～1 460个/L,以无壳纤毛虫丰度最高。无壳纤毛虫在渚碧礁潟湖西部水域（ZB-1）丰度最高,砂壳纤毛虫峰值则出现在永暑礁潟湖中部水域（YS-3）,桡足类幼体丰度最大值出现在美济礁潟湖北部水域（MJ-2）。聚类分析结果显示,3个岛礁潟湖中部区域的微型浮游动物群落相似度较高,溶解氧是影响群落结构的最重要因素,特别是对MJ-3站位影响最为突出。摄食实验结果显示,3个岛礁潟湖水域浮游植物生长率为0.22～1.36 d^-1;微型浮游动物摄食率范围为0.22～0.60 d^-1,微型浮游动物每天约摄食浮游植物现存量的...  相似文献   

Karyotype analysis of Oreochromis mortimeri (Trewavas) and Sarotherodon melanotheron (Rüppell)     

S C Harvey  S F Powell  D D Kennedy  B J McAndrew  & D J Penman 《Aquaculture Research》2002,33(5):339-342

The karyotypes of both Oreochromis mortimeri (Trewavas) and Sarotherodon melanotheron (Rüppell) are shown to consist of 22 pairs of chromosomes (2n = 44). In O. mortimeri, the karyotype is composed of 9 sm/st and 13 t chromosomes. In the case of S. melanotheron, the karyotype is composed of 15 sm/st, 2 m and 5 t chromosomes. The karyotypes of these species are therefore similar to those of the majority of other tilapia species, with that of S. melanotheron being considerably different from that previously reported for this species.  相似文献   

琴鱼的核型、C带和银染分析   总被引：1，自引：0，他引：1  

张德华 《淡水渔业》2007,37(2):16-19

采用秋水仙素-低渗-空气干燥法和银染,以肾细胞为材料,对琴鱼(Ctenogobius giurinus)染色体的核型、C带和银染(Ag-NORs)进行了研究。结果表明:(1)琴鱼2n=44,核型组成为2n=8m+12sm+24t,NF=64,没有异型性染色体分化;(2)所有染色体着丝粒为阳性C带,而且第1对染色体短臂也呈C带阳性,其着色强度与该对染色体上的着丝粒C带相同;(3)Ag-NORs数目在不同细胞中表现出多态性,数目为1~2个,出现1个Ag-NORs的频率最低(9.8%),出现2个Ag-NORs的频率最高(78%),Ag-NORs主要出现在m1对和sm3对同源染色体上。  相似文献   

Molecular cloning of the cDNA encoding the β subunit of thyrotropin and regulation of its gene expression by thyroid hormones in the goldfish, Carassius auratus     

Y. Yoshiura  Y.C. Sohn  A. Munakata  M. Kobayashi  K. Aida 《Fish physiology and biochemistry》1999,21(3):201-210

A cDNA encoding the subunit of thyrotropin (TSH) was isolated from a goldfish (Carassius auratus) pituitary gland cDNA library. By comparing the sequence with other teleost TSHs, a signal peptide of 19 amino acids and a mature hormone of 131 amino acids were predicted for goldfish TSH subunits. The resulting putative mature hormone of 131 amino acids had well-conserved cysteine positions and a putative N-linked glycosylation site; homology was 51–67% with TSHs from other teleosts, 38–43% with tetrapod TSHs, but only 27 and 29% with goldfish GTH-I and -II, respectively. We also examined the effects of thyroid hormones (TH) and thiourea (TU, an inhibitor of TH production) treatments on TSH and GTH subunit gene expressions in the goldfish pituitary gland. After thyroxine (T₄) treatment, circulating T₄ concentration increased and TSH mRNA level decreased. Supressing the amount of circulating T₄ and triiodothyronine (T₃) by TU treatment increased the TSH mRNA level. Moreover, T₄ replacement therapy (simultaneous treatment of both TU and T₄) caused a high level of circulating T₄ and a low level of circulating T₃, and a decrease in the TSH mRNA level. Thus, changing levels of circulating TH exert a negative feedback on the level of TSH subunit mRNA in goldfish in vivo. On the other hand, GTH subunit mRNA levels were not affected by changes in the levels of circulating TH.  相似文献   

甘蔗的起源和进化   总被引：1，自引：0，他引：1  

杨翠凤  杨丽涛  李杨瑞 《广西农业科学》2014,45(10):1744-1750

文章通过总结近20年来有关甘蔗属分类、地理起源、栽培起源与传播、甘蔗进化以及甘蔗基因组进化等的研究结果,全面分析了甘蔗的起源和进化进程,分析结果支持Brandes于1958年提出的假说。建议今后应对割手密种、大茎野生种和热带种之间的相互关系展开深入研究,以便更全面了解甘蔗的起源和进化;同时应开展甘蔗全基因组测序研究、甘蔗叶绿体基因组学研究及构建甘蔗遗传连锁图谱,全面深入剖析甘蔗的遗传结构和驯化进程。  相似文献   

甘蔗多样性微阵列技术（DArT）标记体系的建立     

高轶静  黄东亮  李双喜  段维兴  王泽平  杨翠芳  张革民 《广西农业科学》2014,(5):720-724

[目的]建立成熟、稳定的甘蔗多样性微阵列技术（Diversity array technology,DArT）标记体系,为甘蔗的遗传多样性分析、遗传图谱构建及标记辅助育种等提供新的分子标记方法.[方法]以7份不同种属的甘蔗材料为样本,优化基因组复杂性降低方法并建立甘蔗DArT标记体系,同时应用该体系分析7份材料的遗传多样性.[结果]获得了基于PstⅠ/TaqⅠ酶切组合的最优基因组复杂性降低方法,利用该方法建立了DArT体系.利用DArT体系分析了7份材料之间遗传进化关系,发现供试7份材料的遗传相似系数为0.497～0.811,平均值为0.569.以遗传相似系数0.546为阀值,可以将供试材料分为三大类,其中第一类的GT29号、拔地拉和割手密GXS85-30均为甘蔗属材料,与预期相一致;第二类为河八王2号和滇蔗茅2号,第三类为芒84-8和斑茅GXA87-36.[结论]建立的甘蔗DArT标记体系具有有效性,其遗传相似性分析结果与材料预期的亲缘关系密切程度相一致.  相似文献   

褐菖鮋的染色体核型及其自发畸变率   总被引：1，自引：0，他引：1  

潘蔚明 《水产学报》1996,20(2)

褐菖Ｏ的染色体核型及其自发畸变率潘蔚明（浙江省海洋水产研究所，舟山３１６１００）关键词褐菖Ｏ，核型，染色体畸变ＴＨＥＫＡＲＹＯＴＹＰＥＡＮＤＴＨＥＲＡＴＥＯＦＣＨＲＯＭＯＳＯＭＥＳＰＯＮＬＡＮＥＯＵＳＧＥＮＥＲＡＴＩＯＮＡＢＥＲＲＡＴＩＯＮＯＦＳＥＢ...  相似文献   

Evolutionary implications of two rainbow trout growth hormone genes     

T. T. Chen  L. B. Agellon  C. M. Lin  H. J. Tsai  Peijun Zhang  L. I. González-Villasénor  D. A. Powers 《Fish physiology and biochemistry》1989,7(1-6):381-385

The primary structures of two rainbow trout growth hormone mRNAs (GH1 and GH2) have been deduced by direct sequencing of their respective cDNA clones and portions of the mRNA. Both GH1 and GH2 mRNA contain open reading frames comprised of 630 nucleotides and encode 210 amino acid residues of which 11 are variant. The translated regions of both mRNA are flanked by a short but rather conserved 5′-end, and a relatively long but highly diverged 3′-end. The differences at translated and 3′-untranslated regions suggest that the GH1 and GH2 mRNA originate from different loci. The GH1 and GH2 mRNA are likely transcribed from two distinct loci which were duplicated during tetraploidization of salmonid genome between 50 to 100 million years ago. The GH2 gene has been isolated and sequenced from a rainbow trout genomic library. This gene spans a region of approximately 4 kilobases. The trout GH gene is comprised of 6 exons and 5 introns, in contrast to 5 exons and 4 introns in mammals. The additional intron in the trout gene interrupts the translated regions that are analogous to the last exon of the mammalian counterpart. The alleged internally repeating sequences in mammalian GH, prolactin (Pr1) and placental lactogen (PL) are not observed in the predicted polypeptide sequence of trout GH. In addition, direct repeats that flank exons I, III and V of mammalian GH, Pr1 and PL genes are absent in trout gene. These findings indicate that the rainbow trout GH gene structure does not support the current hypothesis that internally repeated regions in GH, Pr1 and PL arose from a small primordial gene.  相似文献   

Karyological analysis of endangered Caspian salmon, Salmo trutta caspius (Kessler, 1877)     

Mohammad Reza Kalbassi  Salar Dorafshan  Tahereh Tavakolian  Mahmoud Khazab  & Hosein Abdolhay 《Aquaculture Research》2006,37(13):1341-1347

The karyotype and chromosomal characteristics of endangered Caspian salmon, Salmo trutta caspius, in the southern part of the Caspian Sea were investigated. From the total of 60 mitotic metaphases achieved from 15 individuals, 15, 9 and 36 metaphases were with the mode <76, 76 and 80 representing 25%, 15% and 60% of metaphases respectively. So, the most common pattern of chromosome number was 80 (36 metaphases, 60%) and the number of diploid chromosomes was thus confirmed as (2n=80) of this subspecies. The karyotype consists of seven metacentric, five submetacentric and 28 telocentric pairs. The karyological parameters of the Caspian salmon, the centromic index, arm ratio, relative length and length variation range of chromosomes, were 0–0.5, 1–∞, 0.011–0.045 and 0.507–2.028 μm respectively. The total length of chromosomes in haploid series was 44.776 μm and fundamental number of chromosome arms was 104. This study may provide the first knowledge on chromosome analysis in Caspian salmon and add basic information useful for its chromosomal manipulations.  相似文献   

中国贝类染色体研究现状与进展   总被引：1，自引：0，他引：1  

蔡岩  周永灿  冯永勤  谢珍玉  王世锋  袁卫 《热带生物学报》2014,5(3):297-306

对我国已报道的81种贝类染色体研究进行了综述,并结合贝类分子系统进化研究成果,探讨了我国贝类染色体数目与染色体组成的进化趋势。  相似文献