Sperm storage within the female reproductive tract is widespread among animal species with internal fertilization, such as the fish family Poeciliidae, wherein the females possess a sperm storage micropocket (SSP) that can store sperm for up to a year. However, the underlying mechanism and morphogenesis of SSP remain unclear. Here, using histological analysis, we found that the SSP of the western mosquitofish (Gambusia affinis) was associated with protrusions arising from the previtellogenic oocyte (PO). Similar protrusions occur in the PO of Poecilia reticulata, P. latipinna, Xiphophorus helleri, and X. maculatus, suggesting that such PO-derived protrusions might be a universal feature in Poeciliidae. These protrusions exhibit significant differences in structural composition compared to the cytoplasm. Furthermore, the area of these protrusions positively correlates with the total area of the oocytes. After maturing, the protrusions split from the oocytes, leaving behind sac-like structures composed of germinal epithelium, which later develop into the SSP for storing sperm. The bottom of the SSP is composed of a single layer of germinal epithelium. We describe and depict the protrusion formation process in the fish family Poeciliidae during the previtellogenic stage, elucidating the SSP morphogenesis.

A new species, Ceratophysella gracilimucronata sp. nov. from Nan Ling Mountains (Guangdong Province, China), is described. It resembles C. ainu (Yosii, 1972), C. glancei Hammer, 1953 and C. falcifer Cassagnau, 1959 due to the B type chaeotataxy and short and slender mucro. Mitochondrial COI gene sequence of C. gracilimucronata sp. nov. is provided. A key to species of the C. armata group of the Sino-Japanese Region is given.

探讨牛至油对慢性氨氮胁迫下幼鲤各器官组织结构的保护作用,为集约化水产养殖提供参考依据.挑选450尾初始体重为(17.02±0.40)g的幼鲤,随机分为6组:L、L0、L300、L600、L900、L1200(L为对照组,养于正常水体中并饲喂基础饲料;其余5组为试验组,养于<4.87±0.21>mg/L氨氮水体中并分别饲喂添加0、300、600、900、1200 mg/kg牛至油的试验饲料),每组设3个重复,每个重复25尾鱼,养殖试验为期56 d.结果表明,添加量为900 mg/kg时,牛至油对鳃、肝、肾组织发挥的缓解作用最大;当牛至油添加量达到1200 mg/kg时,其缓解氨氮胁迫的作用降低.日粮中牛至油添加量为300、600、900 mg/kg可以显著增加肠绒毛高度;当牛至油添加量达到1200 mg/kg时,牛至油对于肠绒毛的促生长作用减弱.在试验条件下,日粮中添加900 mg/kg的牛至油能够最大程度地缓解由氨氮胁迫造成的幼鲤鳃、肝和肾组织的损伤,并且对于幼鲤肠绒毛的生长具有促进作用.

Environmental DNA (eDNA) is a good indicator of fish diversity and distribution in aquatic environments. This study used metabarcoding to assess fish diversity and distribution in two connected ponds during two sampling periods. The eDNA analysis of surface samples displayed differences in the fish communities between the two connected ponds, while within each sampling site the species detected across the two time points were not always the same. These results revealed poor horizontal transport of eDNA between the two connected ponds alongside poor mixing of eDNA for a single pond’s stocked fish. Additionally, water temperature, pH, and total nitrogen were the key environmental factors affecting fish eDNA spatial and temporal distribution. These findings have important implications for designing eDNA sampling strategies in lentic ecosystems; for example, complete fish diversity in a lentic ecosystem cannot be detected by collecting only surface samples and in only one sampling period.

成年胭脂鱼的因体色如胭脂而得名,是一种常见而美丽的观赏鱼,其演化历史可以追溯到中生代时期(距今1.4亿年).现生的胭脂鱼资源主要见于北美洲,在我国仅在长江流域有分布.目前,胭脂鱼由于人类的活动急剧减少,好在"十年禁渔"让它们迎来了恢复的转机,而科学保护的成果更值得人们期待.

Aquaculture plays a vital role in food security and economic stability worldwide (Houston et al., 2020). Selective breeding to genetically improve production traits has great potential in increasing the efficiency of aquaculture and reducing its environmental footprint (such as habitat destruction and infectious disease outbreaks). To achieve this, we require fish species with excellent economic traits and high-quality genomic data that can be applied at all stages of domestication for ongoing genetic improvement (Houston, et al., 2020). Siluriformes (catfish) is an order of major aquaculture species worldwide, especially in China, the United States, and Vietnam (De Silva and Phuong, 2011; Zhong et al., 2016; Kumar et al., 2020). Redtail catfish (Hemibagrus wyckioides), belonging to the family Bagridae, initially possess a white caudal fin that becomes bright red when it reaches approximately 15 cm. The red-tail catfish is the largest Bagridae fish in body size and weight, reaching 130 cm and 80 kg, respectively (Ng, 1999). Red-tail catfish were originally distributed throughout the Mekong River. In China, they are now only distributed in Yunnan Province. Here, it is a famous indigenous fish due to a variety of excellent economic traits such as high protein content, strong disease resistance, easy domestication, and better production performance; it also has ornamental value (Zhou et al., 2021). Therefore, it has recently become an important aquaculture species in China (Zhou et al., 2019; Zhou et al., 2021). H. wyckioides exhibits marked sex dimorphism in growth, with the males growing much faster than females. Sexual maturation takes over 3 years and a lack of selective breeding has resulted in a decline in the growth rate of red-tail catfish (Zhou et al., 2021). Thus, it is essential to construct a reference genome of H. wyckioides and establish a breeding program to improve the economic characteristics, maintaining and developing the industry, to ultimately create an economically viable local fishing industry.

The complete mitochondrial genome of Ancherythroculter nigrocauda was determined in this study. It contained 1 replication origin, 1 control region (D-Loop), 2 rRNA genes, 13 PCGs, and 22 tRNA genes with the base composition 31.40% A, 25.00% T, 27.60% C, and 16.00% G. Here, we compared this newly determined mitogenome with another one from the same species reported before. The variable sites and the genetic distances between the two mitogenomes were 608 bp and 0.038, respectively. The results from the phylogenetic analysis showed that the genus Ancherythroculter is not a monophyletic group and Ancherythroculter nigrocauda demonstrates a close relationship with Chanodichthys dabryi.

虎是当今体形最大的猫科动物,也是亚洲陆地上最凶猛的食肉动物之一.不要以为虎只能待在丛林中,其实,虎的适应能力远比我们想象的要强.在北方寒冷的西伯利亚山林里,在亚洲南部的热带雨林中,都可以见到虎的身影;甚至在非洲草原上,虎一样可以自由驰骋. 虎位居自然界食物链的顶端.相较而言,寒带的虎体形要大一些,如成年雄性东北虎(西伯利亚虎),体重可达350千克.据报道,最大的野生东北虎可长达3.38米、重388.7千克.

美洲大蠊Periplaneta americana胸腺素基因具有THY1、THY2和THY3三个不同剪接体,其中THY3结构域最多.本研究使用实时荧光定量PCR技术比较分析了THY3在美洲大蠊不同性别、不同发育阶段及不同组织中的表达差异,以及大肠杆菌Escherichia coli诱导对美洲大蠊血淋巴和脂肪体中THY3表达的影响.结果 表明:THY3在成虫期的表达量显著高于其他虫期,雌虫表达量显著高于雄虫,脂肪体表达量显著高于血淋巴、头部、肌肉、体壁组织.雌性成虫体腔注射大肠杆菌3h后血淋巴中THY3表达量显著增高,而在脂肪体中12h后才检测到THY3表达明显上调,研究结果为进一步研究美洲大蠊胸腺素的功能打下了基础.

虎皮鱼是一种小型热带观赏性鱼类,具有形态优美、易饲养等优点.阐述虎皮鱼生活习性、繁殖习性的特征及越冬技术.首次提出了该鱼繁殖时期准确的性别鉴别方法及其一些特殊的繁殖行为.

The insemination process of Myxocyprinus asiaticus egg was studied using artificial fertilization, his-tology, ultrastructural technology methods etc. The observation showed that there is only one micropyle in shell of egg’s animal pole of M. asiaticus. Micropylar apparatus of M. asiaticus belongs to the type of deep concave and short channel. At water temperature of 17-18℃, sperm passed through micropylar apparatus at 3 s after insemina-tion and entered ovum at 5 s. Sperm star light was formed at 10 s after insemination. After 15 min after insemina-tion ovum was in late time of second meiotic division and second polar body appeared. Ovum was in telophase after 20 min and second meiotic division was formed. Male and female pronucleus was fused after 90 min. Ovum was in metaphase of first karyokinesis at 140 min after insemination. At 180 min after insemination first karyoki-nesis was over and second cell was formed. The results showed that in micropylar apparatus of mature egg there is no micropylar cell and other stuff, which is similar to that of most other teleost. The inner diameter of micorpylar apparatus is 2.42 μm and near to the diameter of sperm head. There are many spines in inner walls of anterior mi-cropylar apparatus and holes are arranged in spiral way, which was one of the reasons for monospermy. This study aims to provide basic data for the research of artificial reproduction technology of M. asiaticus.

Chinese sucker ( Myxocyprinus asiaticus ) is an endangered fish species in China which is only distributed in Yangtze River basin. Here we isolated and characterized 34 polymorphic tri and tetra-nucleotide microsatellite loci in the genome of M. asiaticus using 454 sequencing. Of the 73 loci screened, 47 were amplified successfully and 34 were polymorphic. The genetic diversity in M. asiaticus Wanzhou population was moderate with the number of alleles per locus ranged from 2 to 8 (mean 3.97), and the observed and expected heterozygosities ranged from 0.08 to 1.000 (mean 0.50) and from 0.12 to 0.83 (mean 0.55), respectively. These polymorphic microsatellite markers should be useful for further studies of population structure, parentage analysis, and conservation management for this species.

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)).

胭脂鱼是一种名贵的经济鱼类,还具有观赏性.本文简要介绍其进化历程、生物学特性和科学保护.

The bronze gudgeon (Coreius heterodon) and the congeneric species largemouth bronze gudgeon (Coreius guichenoti), two endemic fish species in China, are important economic fishes in local areas. The bronze gudgeon is distributed in Yangtze River and Huanghe River basin, whereas the largemouth bronze gudgeon is distributed only in the middle and upper reaches of Yangtze River. Here, we sequenced the complete mitochondrial genomes of the two species and compared the evolutionary rate differences between the two species. The complete mitochondrial genomes of C. heterodon and C. guichenoti are 16,611 and 16,612 bp, respectively. Both of the complete mitogenome sequences contain 13 protein-coding genes, 2 rRNA subunits, 22 tRNAs and 1 non-coding control region, which are typical vertebrate mitogenomes. The relative rate test shows that the mitochondrial genome of C. heterodon evolves nearly threefold faster than that of C. guichenoti, which is mostly caused by the higher substitution rates in rRNAs and especially in tRNAs in C. heterodon.

The PKD1L3 gene encodes an ion channel protein that can interact with the PKD2L1 protein to form a candidate sour taste receptor. In the present study, we have analyzed the evolutionary patterns of PKD1L3 genes from 10 mammalian species. The results showed that PKD1L3 genes have evolved under a dominant purifying selection force. However, for some branches and sites, PKD1L3 genes were detected to have been operated by positive selection. Moreover, some of these positive evolutionary sites are likely to participate in acid stimulus recognition. In rodents, PKD1L3 genes evolved more rapidly than other mammalian lineages. Combined with other functional research reports, our results suggest that rodents may not be the most appropriate model for functional research on the PKD1L3 gene.

说起珊瑚,人们很可能会想到海洋中五颜六色、千姿百态的珊瑚,也可能会想到著名的澳大利亚大堡礁,还可能想到"海上年轮"的美名.的确,珊瑚是一种神奇而又了不起的动物.

According to the published gD gene sequence of IBRV in GenBank(NC_001847),one specific pair of primer was designed.The gD gene cDNA of Inner Mongolia strain was amplified by PCR and then cloned into PMD19-T plasmids and then sequenced.The results of restriction endonuclease pattern analysis of recombinant plasmid and DNA sequencing demonstrated that the cDNA is belong to the gD gene.The cDNA were 1 559bps long and contain a open reading frame(ORF) of 1 251 bases which encoding 417 amino acid.The comparison of the sequences and phylogenetic analysis showed that the homology of gD gene of Inner Mongolia strain compared with others in GenBank were 99.1% to 99.9% in nucleotide,90.6% to 99.8% of the deduced amino acid sequence.Phylogenetic tree revealed that the gD gene and the AJ004801 strain which were consistently located in the same lineages.Bioinformatics analysis of this sequence showed that the protein of the gD gene was hydrophilic and highly antigenic,includes three potential N-glycosylation site,two potential protein kinase C phosphorylation site,four potential casein kinase Ⅱphosphorylation site.

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.

中华倒刺鲃是杂食性淡水名优鱼类。具有生长快、食性杂、抗病力强等特点。其形态特征、生活习性、繁殖与生长及人工养殖有其自身的特点。