蚌科钩介幼虫比较形态学研究 I.四个种幼虫的形态

本文报道圆顶珠蚌,鱼尾楔蚌,中国尖嵴蚌,卵形脊嵴蚌育儿囊的特点和钩介幼虫的形态,应用光镜和扫描电镜对四种蚌的钩介幼虫形态进行了观察和比较,结果表明,四种蚌的育儿囊均为外鳃类的同生型,钩介幼虫为有钩型幼虫的大小,形状,壳表面,壳钩,棘刺,幼虫丝,感觉毛等在不同种之间存在着差异,文中对这些特征在分类上的意义进行了讨论。     

蚌科钩介幼虫比较形态学研究──Ⅰ.四个种幼虫的形态

本文报道圆顶珠蚌、鱼尾楔蚌、中国尖嵴蚌、卵形尖嵴蚌育儿囊的特点和钩介幼虫的形态。应用光镜和扫描电镜对四种蚌的钩介幼虫形态进行了观察和比较。结果表明,四种蚌的育儿囊均为外鳃类的同生型,钩介幼虫为有钩型,幼虫的大小、形状、壳表面、壳钩、棘刺、幼虫丝、感觉毛等在不同种之间存在着差异。文中对这些特征在分类上的意义进行了讨论。     

珠蚌科六种蚌的钩介幼虫形态比较研究

本文观察了背角无齿蚌、沼纹冠蚌、剑状矛蚌、圆顶珠蚌、刻裂丽蚌和洞穴丽蚌等６种蚌的育儿囊类型;用光镜和扫描电镜观察和研究了幼虫的形态特征。结果表明,前４种蚌的育儿囊属外鳃类的同生型,后２种的育儿囊属外鳃类的四生型;６种幼虫均为钩介幼虫,其中前４种为有钩型,后２种为无钩型;６种幼虫的大小、形态有别,并证明种间幼虫的壳钧和壳饰的亚显微形态显然有异。本文还就６种蚌在Ｓｉｍｐｓｏｎ分类系统中的地位与按它们的育儿囊和钩介幼虫类型得到的归类进行比较。结果表明,Ｓｉｍｐｓｏｎ对６种蚌中３种的分类与归类不妥。本文为研究我国淡水贝类的分类提供一条新的途径,并为建立珠蚌类的自然分类系统积累资料。     

背角无齿蚌生殖细胞及钩介幼虫的扫描电镜观察

本文报告背角无齿蚌的精子、卵子、钩介幼虫的扫描电镜观察。精子头部呈椭圆形，由顶体帽、顶体后区、核区和颈部组成，尾细长呈线状，卵子圆形，有许多卵闰，在生殖腺中有各种不同发育程度的卵细胞，钩介幼虫在育儿囊（外鳃）中发育，有一系列变态过程，表明卵子是分期分批排出，钩介幼虫也是分批发育和成熟的。     

蚌科钩介幼虫的比较形态学研究Ⅱ.六个种幼虫的形态

研究了真柱矛蚌、剑状矛蚌,洞穴丽蚌、角月丽蚌、三解帆蚌、褶纹完蚌等六种蚌的育作囊的类型和钩介幼虫的形态,应用光镜及扫描电僮对钩介幼虫的形态结构进行了观察和比较。结果表明 柱矛蚌、剑状矛蚌、三角帆蚌、褶纹冠的育儿囊为外鳃类同生型,洞穴丽蚌、角月丽蚌的育儿囊为外鳃类四生型、钩介幼虫可为二类：真柱矛蚌、剑状矛蚌、褶 纹冠蚌为有钩型,三角帆蚌、油穴丽蚌、角月丽蚌为无钩型。一些细微结构在不同种之间也存在着差     

绢丝丽蚌寄生变态发育的研究

绢丝丽蚌钩介幼虫在雌蚌外鳃中发育成熟后于冬季排放到体外,而后寄生到宿主鱼的鳃丝进行变态发育,寄生期历时近4个月.寄生后3d,内、外足丝消失;35d后,肉足形成;90d后,肠、闭壳肌、肾脏和鳃原基等生成;壳面加厚且外凸.次年春季,钩介幼虫变态发育成大小为253.37×273.26×179.96μm的稚蚌,脱离鱼鳃营独立生活     

钩介幼虫壳表面结构的扫描电镜观察

利用扫描电镜技术研究了鱼尾楔蚌和圆顶珠蚌钩介幼虫的形态特征,并进行了比较．结果表明,两种蚌的钩介幼虫均为有钩型,幼虫的大小、形态、壳表面、壳钩、棘刺等存在着差异、对这些特征在分类学上的意义进行了讨论．     

背瘤丽蚌胚胎发育的初步研究

用显微技术研究了背瘤丽蚌(Lamprotula leai)胚胎发育和钩介幼虫结构。结果表明,背瘤丽蚌卵为均黄卵,受精卵分布在雌蚌内、外鳃腔中进行胚胎发育;胚胎发育同步;胚胎发育过程包括受精卵、卵裂期、囊胚期、原肠期、膜内钩介幼虫期和钩介幼虫期;卵裂为螺旋不等完全卵裂;未受精的成熟卵在鳃腔内退化;胚胎发育期与胚胎、外鳃和内鳃颜色相关;怀卵母蚌胚胎在外界环境变化时容易全部流产。分析认为背瘤丽蚌胚胎发育期的繁殖特征可指导人工苗种生产。     

绢丝丽蚌胚胎发育的研究

绢丝丽蚌卵为均黄卵,爱精卵在雌蚌外鳃中进行胚胎发育,其卵裂为不等完全卵裂。在秋季自然常湿（水温变幅为２４－８℃）时,胚胎发育历时５１ｄ,经过卵裂期、原肠期,发育为具有透明原壳、过钩、闭壳肌丝、内足丝、刚毛和外足丝的成熟钩介幼虫。胚胎发育的不同时期与外鳃特征具相关性。     

江西青岚湖圆顶珠蚌的种群结构与繁殖特征研究

2008年7月至2009年7月研究了江西青岚湖圆顶珠蚌(Unio douglasiae)的种群结构与繁殖特征。从其种群结构的周年变动情况来看,该种群趋于稳定状态,壳长40-65mm的个体占大多数。在采集的标本中,最大个体壳长为83.6mm,最小个体壳长为20.3mm。圆顶珠蚌自然种群性比为1:1.20,性成熟最小雌体壳长为27.6mm,体重为2.62g;最小雄体壳长为27.9mm,体重为2.21g;5至6月间繁殖盛期,检测到最小妊娠个体壳长为29.8mm,体重为2.98g,推断一周年的圆顶珠蚌可能达到性成熟。根据圆顶珠蚌生殖细胞的发育规律和滤泡的变化特点,性腺发育分为生长期和成熟期、排放期、恢复期;属多次产卵类型。育儿囊属外鳃型,胚胎在胶质索中发育,钩介幼虫成熟后,胶质索消失成黏液状,成熟钩介幼虫附在新形成的黏液丝上排出体外。妊娠母蚌在受到刺激后,易发生流产,提前排出胶质索。繁殖期为2至7月,4、5、6月为繁殖高峰期,妊娠率分别为80.43%、84.21%和78.05%。平均繁殖力为(183.72±6.43)千粒/个,最大繁殖力为344.64千粒/个,壳长为54.5mm;最小繁殖力为49.95千粒/个,壳长为29.8mm。繁殖力与壳长和体重显著相关。这些结果不仅可以丰富淡水蚌的生物学内容,也能为淡水蚌保护和湖泊与河流的规范管理提供理论依据。       

GENETIC DIVERSITY OF FIVE FRESHWATER MUSSELS IN GENUS ANODONTA (MOLLUSCA: BIVALVIA) REVEALED BY RAPD ANALYSIS

Unionidae(Bivalvia)are distributed infreshwaters,and represent a significanttaxonof benthic community[1].In China,freshwater mussels are abundant resources[2].Since1949,substantial investigations onthe unionidfau-na had been undertakenin China[3—8].Withreference tooverseas research[9,10],a preliminary reorganization onthe Unionidae was performed accordingtosome classifica-tion characteristics such as shell shape,larvae character-istics,and breeding habit[11].Due tothe serious conver-gence of freshwater muss...     

通过RAPD分析揭示五种淡水无齿蚌（软体动物门：双壳类）的遗传多样性

Unionidae(Bivalvia)are distributed infreshwaters,and represent a significanttaxonof benthic community[1].In China,freshwater mussels are abundant resources[2].Since1949,substantial investigations onthe unionidfau-na had been undertakenin China[3—8].Withreference tooverseas research[9,10],a preliminary reorganization onthe Unionidae was performed accordingtosome classifica-tion characteristics such as shell shape,larvae character-istics,and breeding habit[11].Due tothe serious conver-gence o…     

In vitro culture of glochidia from the freshwater mussel Anodonta cygnea

Abstract. Larvae of the freshwater swan mussel, Anodonta cygnea , were cultured in artificial media at the controlled temperature of 23°±2°C, with successful metamorphosis for the first time. The artificial medium contained a mixture of M199, common carp plasma, and antibiotics/antimycotics. Glochidia were reared to the juvenile stage in the medium after 10–11 d of culture. After 15 d of controlled feeding with phytoplankton, the juveniles showed an elongated shell with several growth lines. Larval survival was 34.3±9.3%, whereas the proportion undergoing metamorphosis was ≤60.8±4.2%. The ultrastructure of early developmental stages was observed by scanning electron microscopy, from the glochidial to the juvenile stage. Glochidia had a hooked shell, with two equal triangular valves formed by a calcareous layer with numerous pores and covered by a thin cuticle of chitin–keratin. The appearance of the complete foot within 11 d of in vitro culture was considered the final feature of metamorphosis to the juvenile stage. The main alteration during juvenile development was the formation, under the glochidial shell, of a new periostracum with growth lines. The prominent foot, gradually covered by long, dense cilia, showed rhythmical movements involved in the capture of particulate matter. Similarly, cilia and microvilli present in the mantle also performed the same role. Longer cilia, sparsely distributed in the mantle, may function as chemotactile sensors.     

Scanning electron microscopy of glochidia and juveniles of the freshwater mussel,Hyriopsis myersiana

Summary

The ultrastructure of early stages of the mussel, Hyriopsis (Limnoscapha) myersiana (Lea, 1856), was observed by scanning electron microscopy from the glochidial period until the onset of the juvenile stage 10 days later. Further observations were performed for an additional 13 days to assess juvenile development. Glochidia extracted from the brood chambers have a hookless, semi-oval and equivalve calcareous shell with numerous pores in the internal surface, pits in the external surface and cuticular spines in the ventral region. Keratin fibers with a random arrangement in the cuticle of the glochidial shell were also detected. The appearance of the foot within 10 days of in vitro glochidial culture was considered the main feature of metamorphosis to the juvenile stage. Another change during the following 13 days was the formation of a new periostracum exhibiting growth lines under the old glochidial shell. This development occurs mainly in the anterior region and is followed by hardening of the periostracum matrix by calcium deposition. Periostracum growth gradually became apparent in the lateral and posterior regions at the end of this period. The retraction of spines and the alteration of the external surface of the old shell are also described. It is speculated that transcuticular filaments identified in the juvenile stage may have sensory or metabolic exchange functions. The prominent foot, gradually covered by long dense cilia, shows rhythmical movements which suggest a role in feeding. Similarly, cilia present in the mantle may also be involved in the capture of food, while microvilli may facilitate absorption of dissolved materials. Longer cilia, sparsely distributed in the mantle, may function as chemo- or tactile sensors.     

MARSUPIAL ANATOMY OF THE DEMIBRANCH OF MARGARITIFERA MARGARITIFERA (LIN.) IN NORTHEASTERN NORTH AMERICA (PELECYPODA: UNIONACEA)

On morphological, biological and behavioral characters the freshwatermussel family Margaritiferidae generally is accepted as themost primitive of the Unionacea. Microscopic examination ofthe marsupial demibranch further supports this assumption, inthat the interlamellar junctions lack elastic properties necessaryfor lateral hyperextension of the gravid demibranch. A temporarymodification of marsupial anatomy in the form of a fibrous elastinaccessory material is produced during the final phase of glochidialincubation. Its appearance coincides with the enlargement ofepithelial cells that line the marsupium and interlamellar junctions.The material, which is situated between the glochidial massand the inner lamellar surfaces, may provide increased aerationand support for the resting glochidia. (Received 18 February 1978;     

Breeding patterns in the oniscid isopod,Porcellio ficulneus Verh., at high temperature and under different photophases

Summary

Porcellio ficulneus Verhoeff inhabits xeric Mediterranean grassland habitats. During winter vitellogenesis takes place and mancas are released in April. Under natural conditions some oocytes (about 20%) were lost. Both high temperature (25°C) at long or short photophases affected the reproductive pattern. Thus at 25°C and constant light vitellogenesis was markedly shorter than under field conditions. Oocytes matured sooner, but many were resorbed. The marsupium was formed earlier and contained fewer eggs. In some cases mancas that had developed could not emerge from the marsupium and died inside. In conclusion, P. ficulneus responds to warmer conditions by breeding earlier and reducing the number of offspring.     

河蚌C反应蛋白一级结构分析

经亲和层析纯化的河蚌 C反应蛋白 ( CRP)具有 SDS- PAGE纯度 ,用经改进的双偶联 Ed-man方法测得其 N端残基为谷氨酸 ,而不是高等动物 (人与家兔 ) C反应蛋白 N端的焦谷氨酸 .河蚌 C反应蛋白 N端的一级结构由固相 Edman方法测得 ,依次为 H2 N- E- T- A- Y- S- C- I- T- A- V- ;C端的一级结构由羧肽酶 A降解法测得 ,依次为 - L/V- S- S- T- Y- COOH,也不同于人和家兔的 C反应蛋白 .在河蚌 CRP的胰蛋白酶酶解肽段中 ,其 N端及 C端的结构也得到了证实 .河蚌 C反应蛋白经 V8蛋白内切酶酶解 ,溴化氰裂解 ,肽段经 HPLC反相柱分离 ,共得到 35个肽段 ,所有肽段的氨基酸序列均由气相氨基酸自动分析仪测得 .结合河蚌 C反应蛋白的胰蛋白酶酶解肽段的分析结果 ,其一级结构已初步拼接完成 .在其一级结构中发现有类似于其它 CRP的 Ca2 + 结合部位和磷酸胆碱结合部位 .河蚌 C反应蛋白的分子结构中存在微观不均一性 .从已知河蚌 C反应蛋白的分子特点 ,包括分子量 ,糖基化比例 ,一级结构不均一等特点 ,可以推测它与高等动物的免疫蛋白有许多相关之处 .对于河蚌 C反应蛋白分子结构的分析 ,将有助于免疫系统蛋白的发生 ,进化等方面的研究     

Site selection and attachment duration of Anodonta woodiana (Bivalvia: Unionacea) glochidia on fish hosts

The relationship between parasitic glochidia of Anodonia woodiana (Unionidae: Anodonti-nae) and potential fish hosts was investigated in the laboratory. Intensity of parasitism was highest on the exotic fish Gambusia affinis , lower on the native species Puntius semijascio-latus and Metzia takakii , and least on Rhodeus sinensis . Glochidia generally attached at fin margins, particularly the pectorals and caudal. In Gambusia affinis , the incidence of glochidia on the pectorals was higher than would be expected on the basis of ratios between fin margin lengths. Apparently, the role of the pectoral fins in locomotion makes them more liable to glochidial contact, thereby increasing their susceptibility to attachment.
The duration of glochidial attachment was shortened as temperatures increased. Mean values ranged from 14-4 days at 15°C to 6 days at 27°C. At 33°C glochidia rapidly detached and metamorphosis was unsuccessful. Significantly, water temperatures in A. woodiana habitats in Hong Kong rarely exceed 30°C.