长江刀鲚mor-4k13基因的分离鉴定及表达分析

分布于长江的刀鲚(Coilia nasus)具有洄游和定居两个生态型,生殖洄游是区别两者的主要表征。为了探索嗅觉受体(OR)基因是否参与了刀鲚的生殖洄游过程,本文采用RACE技术从洄游型刀鲚中获得了mor-4k13基因,该基因全长1 098 bp,编码区长963 bp,单外显子结构,可编码320个氨基酸。预测表明,mor-4k13基因编码的蛋白质,为7个疏水性的α-螺旋跨膜结构,属G-蛋白偶联受体,有胆固醇和油酸两个配体。MOR-4K13蛋白与已报道的其他鱼类OR蛋白的同源性在40%~68%之间,其中,与近缘种大西洋鲱(Clupea harengus)嗅觉受体蛋白同源性高达68%。采用Real-time PCR方法对10个组织或器官所作的荧光定量分析显示,mor-4k13基因在定居型刀鲚嗅囊和性腺中高表达,在肌肉、眼球、胃壁、肝和鳃中低表达,心肌中几乎不表达。mor-4k13基因在洄游型刀鲚嗅囊中的表达量总体高于定居型,且洄游型雄性刀鲚嗅囊中此基因的表达量约是其雌性嗅囊中的3倍。这表明mor-4k13基因不仅与嗅觉功能和性腺发育相关,也可能与生殖洄游习性相关,不同性别的个体间也存在着嗅觉能力的差异。     

长江安庆段刀鲚寄生线虫群落结构及感染特征

为理清刀鲚(Coilia nasus)洄游时间与体内寄生线虫的关系,于2018年4—7月在长江安庆段调查了刀鲚寄生线虫的感染情况及群落结构。结果显示,刀鲚线虫感染率为96.0%,平均感染强度为8.06±7.26,平均感染丰度为7.74±7.29。经ITS分子标记共鉴定出7种线虫,其中异尖属2种,宫脂属4种,针晶蛔属1种,均为海水性寄生虫,可作为刀鲚有海水生活经历的生物标记。其中派氏异尖线虫(Anisakis pegreffii)的感染率最高,为84.5%,其次为内弯宫脂线虫(Hysterothylacium aduncum)(31.0%),二者的感染强度和感染丰度也较高,其中平均感染强度分别为6.40±6.08和2.81±2.49,平均感染丰度分别为5.41±6.05和0.87±1.90;派氏异尖线虫感染丰度和感染强度在洄游早期呈上升趋势,到6月下旬稍有降低但不显著(P>0.05),内弯宫脂线虫感染丰度和强度则均表现为下降趋势。刀鲚寄生线虫的群落结构在不同洄游时间也有所差异,其中刀鲚感染线虫的平均物种丰富度和Brillouin多样性指数均呈下降趋势,但优势物种一直是派氏异尖线虫,...     

长江安庆江段刀鲚耳石微化学及洄游生态学意义

刀鲚(Coilia nasus)属辐鳍鱼纲、鲱形目、鳀科,是我国长江下游一种传统的名贵经济鱼类。长江安徽江段为刀鲚的主要分布区之一,但近年来由于人类活动干扰、栖息地衰退及过捕等原因,资源量急剧下降。近期发布的《国家重点保护野生动物名录》水生野生动物调整方案已拟将刀鲚列入国家二级重点野生动物保护名录。为客观了解长江安庆江段刀鲚的生境"履历"及探讨其洄游史,利用X射线电子探针微区分析技术对2008年7月捕获于长江安庆江段的10尾刀鲚(均为传统意义上的长颌鲚)进行了耳石微化学研究。结果表明:这些个体均具典型的溯河洄游习性。从耳石核心到边缘定量线分析结果表明,耳石的沉积过程中元素Sr/Ca比值波动显著,不仅有对应淡水生境的低值(3)阶段,还具有对应河口半咸水、海水生境的高值(3)阶段。这种现象亦得到了16色Sr元素面分布分析结果的印证。根据耳石淡水系数、Sr/Ca比值高低波动特征及Sr元素面分布图谱的差异性可以将这些刀鲚分为3种淡-海水生境转换生活史类型。这种现象明显地反映出长江安庆江段刀鲚的群体具有个体组成和洄游模式的多样性。     

西藏拉萨河鱼类内寄生蠕虫的种类组成及其群落特征

2004年7月对西藏拉萨河鱼类的体内寄生蠕虫进行了调查,共采集到7种鱼类,其中6种隶属于裂腹鱼亚科,1种隶属于鳅科。在这些鱼类中,共发现了2种棘头虫和1种棘头虫未定种、3种线虫、3种绦虫及异肉吸虫属(Allocreadium)的种类。它们分别是青海新棘吻虫(Neoechinorhynchus qinghaiensis)、裸鲤棘头虫(Echinorhynchus gymnocyprii)和新棘吻虫未定种(Neoechinorhynchus sp.),希蚋杆咽线虫(Rhabdochona hellichi)、对盲囊线虫(Contracaecum sp.)和胃瘤线虫(Eustrongylides sp.),东方短结绦虫(Breviscolex orientalis)、舌状绦虫(Ligula sp.)和裂头绦虫(Diphyllobothrium sp.),以及寄生裂腹鱼的异肉吸虫(Allocreadium spp.)。对青海新棘吻虫、杆咽线虫、东方短结绦虫、异肉吸虫和新棘吻虫未定种在鱼类中发育成熟的寄生虫进行了形态描述。从不同的裂腹鱼中获得的异肉吸虫属的种类未能鉴定到种;其他没有鉴定到种的寄生虫主要是利用鱼类作为中间寄主的种类,其种类鉴定则有赖于成虫的获得。迄今为止,青海新棘吻虫和裂腹鱼异肉吸虫(A.schizothoracis)仅在裂腹鱼类中被发现,可能表明裂腹鱼具有特异性的棘头虫和异肉吸虫。在所检查的7种鱼类中,除异齿裂腹鱼(Schizothorax oconnori)没有发现蠕虫外,其他6种鱼都发现了4~6种蠕虫,显示较高的物种丰富度;5种裂腹鱼蠕虫群落的Shannon-Wiener指数较高(0·6131~1·5434),而细尾高原鳅(Triplophysa stenura)的较低(0·2911);5种裂腹鱼寄生虫群落之间的相似性相对较高,为(0·1732±0·2303)~(0·3751±0·2758),而裂腹鱼与细尾高原鳅的相似性则较低,为(0·0288±0·0877)~(0·0916±0·1618)。在这些寄生蠕虫中,以鱼类为中间宿主的寄生虫种类有4种,他们都以鸟类为终末寄主,因而也在一定程度上反映了该地区的动物区系组成。     

洞庭湖中是否存在溯河洄游型刀鲚

利用电子探针微区分析(EPMA)技术, 分析了2018年8月采自湖南省岳阳市洞庭湖畔水产市场2尾刀鲚(Coilia nasus)干制个体的矢耳石中锶和钙微化学特征。定量线分析结果显示, 2尾样本的耳石锶钙比值(Sr/Ca×1000)波动显著, 从耳石核心到边缘可分别出现对应淡水生境的锶钙比值<3的低值区, 对应于半咸水生境的3—7高值区和再次为对应于淡水生境<3的低值区。面分布分析结果更直观显示两尾刀鲚个体的耳石从核心到边缘对应于不同盐度生境的锶含量变化图谱, 即从耳石核心到边缘可分别出现对应于淡水生境的蓝色区域, 对应长江口外半咸水生境的黄绿色区域和再次对应于淡水生境的蓝色区域。这种淡水-半咸水-淡水的生境转换显示出了上述个体的典型溯河洄游生活史“履历”。研究显示目前距长江河口约1400 km的洞庭湖中仍可能存在溯河洄游型刀鲚个体。     

基于耳石微化学的长江安徽和县江段刀鲚生境履历重建

为了解长江刀鲚(Coilia nasus)的“生境履历”, 利用电子探针微区分析技术研究了2015年5月17日在长江安徽和县江段捕获的刀鲚短颌鲚与长颌鲚类型耳石Sr和Ca微化学特征。短颌鲚的耳石Sr/Ca值变化动态为2类, 一类比值稳定在2.00左右(1.65±0.87—2.03±0.96), 反映了其纯淡水的生境履历; 另一类比值波动显著, 不仅具有对应淡水生境的低值(2.39±1.18—2.63±0.85), 还具有对应半咸水生境的高值(3.22±1.17—3.29±1.14), 显现了其江海生活的生境履历。长颌鲚耳石的Sr/Ca值均波动显著, 同时具有对应淡水生境的低值(1.35±1.07—2.37±1.04)和半咸水、海水生境的高值(3.47±1.09—8.35±1.25), 表现了其均为溯河洄游的生境履历。Sr面分析结果也与上述Sr/Ca值的结果相印证。长江安徽和县江段刀鲚资源组成复杂, 群体可由纯淡水型和江海生活型的个体共同组成。     

从线粒体控制区全序列变异看短颌鲚和湖鲚的物种有效性

经克隆测序获得我国七丝鲚(Coilia grayii)、凤鲚(C. mystus)、刀鲚(C. nasus)和短颌鲚(C. brachygnathus)以及太湖湖鲚(C. nasus taihuensis)等4个种和1亚种32尾个体的mtDNA D-loop区全序列, 以日本鳀(Engraulis japonicus)和秘鲁鳀(E. ringens)为外类群构建了中国鲚属的分子系统发育树, 并讨论了短颌鲚和湖鲚的物种有效性。结果显示, 七丝鲚的D-loop区全序列长1,208 bp, 凤鲚1,279–1,361 bp, 刀鲚1,252–1,290 bp, 短颌鲚1,214–1,252 bp, 湖鲚1,252–1,442 bp, 除七丝鲚外的其他种类个体间均表现出序列长度的多态性。短颌鲚、刀鲚和湖鲚三者间的平均K 2-P遗传距离仅为0.011–0.020, 明显小于它们与凤鲚、七丝鲚及外类群间的遗传距离(0.051–0.349)。以邻接法和最大简约法构建的系统发育树表明, 刀鲚、短颌鲚及湖鲚均未各自构成单系, 而是共同构成一个单系群, 三者并未发生显著分化。研究表明, 短颌鲚和湖鲚为刀鲚的淡水生态型种群, 并非有效物种。系统发育分析表明, 中国鲚属3个有效物种间以凤鲚最为原始, 刀鲚和七丝鲚为姐妹群, 处于较进化的位置。推测凤鲚可能是鲚属祖先种最早从起源中心扩散到西北太平洋的后裔, 而刀鲚和七丝鲚则是凤鲚在演化过程中分别适应寒冷和温暖气候而分化出的物种。     

中国狗寄生虫名录

1.本文将中国已发现之狗寄生虫,列成名录。 2.迄目前止,中国已知之狗寄生虫自然感染者有原虫12种、线虫18种、吸虫34种、絛虫17种、蛭1种,蜱25种、螨4种、舌形虫2种、昆虫18种,计131种;实验感染者有线虫2种、棘头虫1种、吸虫13种,计16种,共147种。 3.上海发现的马氏斜睾吸虫Plagiorchis(M.)massino Petrov and Tichonov,1927及Alaria sp.均为国内狗寄生虫之新纪录。     

四川省鸡的寄生虫调查简报

1982年—1985年,在全省9个农业区40个调查县中,解剖鸡1409只,对其寄生虫作了系统的调查研究。经分类鉴定,发现鸡有体内外寄生虫70种(不包括原虫)。隶属于24科40属。其中线虫8科12属16种;吸虫8科13属31种;绦虫4科9属14种;蜘蛛昆虫4科6属9种。本调查在鸡体内首次发现美彩膜钩绦虫Hymenosphenacanthus venustus、角杯尾吸虫Coty-lurus coruntus、凹形隐叶吸虫Cryptoutyle cencava、长刺光口吸虫Psilochamus longicirratus,鸡为上述虫种的新宿主。厚尾束首线虫Streptocara crasscauda通常寄生于鸭,苏联曾有寄生于鸡的记载。本调查在叙永县一鸡…     

丹江口水库鲤肠道寄生蠕虫群落结构与季节动态

2004年2月到2005年11月在丹江口水库库区206尾鲤(Cyprinus carpio)肠道中检获蠕虫11种,其中复殖吸虫3种,线虫5种,棘头虫2种,绦虫1种。总体感染率为45.63%,平均感染丰度为4.23±12.65,平均感染强度为9.29±17.48,其中饭岛盾腹吸虫(Aspidogaster ijimai)的总感染率(25.24%)和平均感染丰度(1.76±6.46)最大,瓣睾鲫吸虫(Carassatrema lamellorchis)的感染强度(25.00±46.68)最大。除部分平均感染丰度较低的线虫如鲤带巾线虫(Cucullanus cyprini)外,其他蠕虫的分布类型均为聚集分布,蠕虫群落多样性指数为4.63,均匀度指数为0.60,对群落多样性的季节动态分析表明,各季节群落多样性和均匀度波动较大,并无明显变化规律。每尾鲤感染蠕虫种数多在1—4种之间,所有感染的11种蠕虫中优势种为饭岛盾腹吸虫;次优势种为日本侧殖吸虫(Asymphylodora japonica)、中华许氏绦虫(Khawia sinensis)、瓣睾棘吸虫和鲤长棘吻虫(Rhadinarhynchus cyprini);非优势种为对盲囊线虫(Contracaecum sp.)、鲤带巾线虫、鲤杆咽吸虫(Rhabdochona cyprini)、黄颡刺盖线虫(Spinitectus gigi)、毛细线虫(Capillaria sp.)和木村小棘吻虫(Micracanthorhynchina motomurai)。在种间协调关系方面,鲤杆咽线虫和瓣睾鲫吸虫、鲤长棘吻虫和饭岛盾腹吸虫、对盲囊线虫和木村小棘吻虫、鲤长棘吻虫和木村小棘吻虫之间分别存在显著正关联。对优势种和次优势种蠕虫中种群的季节动态分析表明,鲤寄生蠕虫各组分的感染率和平均感染丰度存在显著的季节差异,在秋、冬季节的感染水平普遍比较高,而到春夏则急剧下降,但中华许氏绦虫无显著季节变化。     

Seasonal occurrence of helminths in the anadromous fish Coilia nasus (Engraulidae): parasite indicators of fish migratory movements

To understand the seasonal migration of the anadromous Coilia nasus , we attempted to identify the parasites infecting C. nasus and determine their seasonal occurrence. From June 2007 to July 2008, a survey of 775 C. nasus individuals from the estuary of the Yangtze River and the coast of the East China Sea revealed more than 7,300 parasites associated with the gills and alimentary tracts of C. nasus . The following 6 helminth taxa were identified, i.e., the monogeneans Heteromazocraes lingmueni and Helciferus tenuis, the digenean Elytrophallus coiliae, the acanthocephalan Acanthosentis cheni , and larvae of the nematodes Anisakis simplex and Contracaecum sp., all of which are marine or brackish-water parasites. The absence of freshwater helminths suggested that the parasites acquired in freshwater may have been accidentally, and easily, lost by the time the fish had reached the estuary and coast. Contrary to seasonal occurrence of the parasites' life cycles, the lowest mean abundance and prevalence of H. lingmueni and A. cheni occurred in August, which suggested the immigration of C. nasus from freshwater to the Yangtze estuary, with lower parasite burdens. The highest mean abundance and prevalence of the nematodes A. simplex and Contracaecum sp. in May and June, and the lowest in August, indicated the arrival of the fish from the coast and the Yangtze River, to the estuary, respectively. These findings suggested that a majority of the fish prepared for spawning migration in the estuary in spring and early summer and returned to the estuary after spawning in the lower and middle reaches of the Yangtze River in late summer.     

Richness and diversity of helminth communities in the Japanese grenadier anchovy, Coilia nasus, during its anadromous migration in the Yangtze River, China

To determine the relationship between the species richness, diversity of helminth communities, and migration distance during upward migration from coast to freshwater, helminth communities in the anadromous fish Coilia nasus were investigated along the coast of the East China Sea, the Yangtze Estuary, and 3 localities on the Yangtze River. Six helminth species were found in 224 C. nasus . Changes in salinity usually reduced the survival time of parasites, and thus the number of helminth species and their abundance. Except for the 2 dominant helminths, the acanthocephalan Acanthosentis cheni and the nematode Contracaecum sp., mean abundance of other 4 species of helminths was rather low (<1.0) during the upward migration in the Yangtze River. Mean abundance of the 2 dominant helminths peaked in the Yangtze Estuary and showed no obvious decrease among the 3 localities on the Yangtze River. Mean species richness, Brillouin's index, and Shannon index were also highest in the estuary (1.93 ± 0.88, 0.28 ± 0.25, and 0.37 ± 0.34, respectively) and did not exhibit marked decline at the 3 localities on the Yangtze River. A significant negative correlation was not seen between the similarity and the geographical distance (R = -0.5104, P = 0.1317). The strong salinity tolerance of intestinal helminths, relatively brief stay in the Yangtze River, and large amount of feeding on small fish and shrimp when commencing spawning migration perhaps were responsible for the results.     

Multiple freshwater invasions of the tapertail anchovy (Clupeiformes: Engraulidae) of the Yangtze River

Freshwater fish evolved from anadromous ancestors can be found in almost all continents. The roles of paleogeographic events and nature selection in speciation process often are under focus of research. We studied genetic diversity of anadromous and resident tapertail anchovies (Coilia nasus species complex) in the Yangtze River Basin using 4,434 nuclear loci, and tested the history of freshwater invasion of C. nasus. We found that both C. brachygnathus and C. nasus were valid species, but the resident C. nasus taihuensis and the anadromous C. nasus were not different genetically based on Bayes factor species delimitation (BFD*). Maximum likelihood tree, Network, PCA and STRUCTURE analyses all corroborated the results of BFD*. Two independent freshwater invasion events of C. nasus were supported, with the first event occurring around 4.07 Ma and the second happened around 3.2 Ka. The time of the two freshwater invasions is consistent with different paleogeographic events. Estimation showed that gene flow was higher within ecotypes than between different ecotypes. F‐DIST analyses identified 120 disruptive outliers by comparing C. brachygnathus to anadromous C. nasus, and 21 disruptive outliers by comparing resident C. nasus to anadromous C. nasus. Nine outliers were found to be common between the two comparisons, indicating that independent freshwater invasion of C. nasus might involve similar molecular pathways. The results of this study suggest that adaptation to landlocked freshwater environment of migratory fish can evolve multiple times independently, and morphology of landlocked ecotypes may cause confusion in their taxonomy.     

Helminth parasites of the tropical gar, Atractosteus tropicus Gill, from Tabasco, Mexico

A total of 8 helminth species were recorded in an examination of 43 tropical gar, Atractosteus tropicus Gill, collected at the Pantanos de Centla Biosphere Reserve, Tabasco, Mexico. The parasite species included 1 adult trematode, 3 metacercariae, 1 cestode, 1 adult nematode, and 2 nematode larvae. Six of these 8 species were rare, with low prevalence (< 17%) and abundance (< 1.0 helminths per examined fish). The larvae of Contracaecum sp. were the most abundant in the sample, constituting 60% of the total helminths (64% prevalence, 3.8 +/- 5.2 abundance), followed by the cestode Proteocephalus singularis, constituting 18% of the worms (30.5% prevalence, 1.1 +/- 3.0 abundance). Species richness, individual parasite abundance, and diversity were low in the infracommunities. The recording of 3 specialist species in the tropical gar confirms that the helminth fauna of gar has an appreciable degree of specificity. This study indicates the importance of ecological determinants of richness in helminth communities of the tropical gar.     

Genetic structure and diversity of Japanese kokanee Oncorhynchus nerka stocks as revealed by microsatellite and mitochondrial DNA markers

Genetic structure and diversity of nine Japanese kokanee (landlocked) Oncorhynchus nerka stocks and anadromous O. nerka from the North Pacific and the Canadian Lake Cultus population were examined using microsatellite and mitochondrial DNA. Sequence analyses of the cytochrome b region of mtDNA for Japanese kokanee O. nerka stocks on Honshu and Hokkaido islands revealed that most Japanese stocks were monomorphic of one major haplotype, which was also dominant in the Lake Cultus population and anadromous O. nerka in the North Pacific. Assignment tests using microsatellite DNA revealed that there was no clear-cut population structure in Japanese kokanee O. nerka stocks.     

西藏羊卓雍错高原裸鲤肠道寄生蠕虫的群落生态

为研究西藏羊卓雍错Yamdrok Lake高原裸鲤肠道寄生蠕虫的群落生态,探索寄生虫与西藏高原环境和独特的鱼类宿主三者之间的相互关系,以肠道寄生蠕虫为对象,于2020年7月对180尾高原裸鲤Gymnocypris waddellii [雌性120尾,雄性60尾,全长22.20—49.20 cm,平均全长(36.76±4.18) cm,体重77.3—896.7 g,平均体重(425.92±148.27) g]进行了剖检,对群落结构和种间关系等群落生态进行了分析。羊卓雍错高原裸鲤肠道寄生蠕虫群落由5个物种构成,分别为聂氏似短节绦虫Parabreviscolex niepini、对盲囊线虫Contracaecum eudyptulae、束首线虫未定种Streptocara sp.、新棘吻虫未定种Neoechinorhynchus sp.和异肉吸虫未定种Allocreadium sp.。感染率从高到低依次为新棘吻虫未定种、聂氏似短节绦虫、异肉吸虫未定种、对盲囊线虫和束首线虫未定种。平均丰度从高到低依次为聂氏似短节绦虫、新棘吻虫未定种、束首线虫未定种、异肉吸虫未定种和对盲囊线虫。群落的Marga...     

Age at maturity in landlocked and anadromous Atlantic salmon parr from two Québec rivers

Synopsis Age at maturity in male Atlantic salmon parr from landlocked populations in the Watshishou and Musquaro Rivers is significantly greater than in anadromous populations from the same rivers. We conclude that high post-smolt mortality in anadromous stocks is conducive to male parr maturity at an early age. We also suggest that the lower proportion of maturing male parr in landlocked stocks may be related to competition among males for mates and the smaller ultimate size of spawning adult landlocked salmon.