青蛤抗菌肽基因的克隆及其在组织间的表达分析

利用构建的SMART-cDNA文库及高通量测序方法,获得了青蛤抗菌肽macin家族相关基因(mytimacin)的全长序列,采用荧光定量PCR方法分析了mytimacin在青蛤各组织的表达情况,并在鳗弧菌胁迫下分析了mytima-cin在外套膜中的时序表达关系。结果表明,mytimacin基因全长461bp,开放阅读框为261bp,编码86个氨基酸,具有24个氨基酸的信号肽序列;荧光定量PCR结果显示,该基因在血液、肝脏、外套膜、鳃和闭壳肌等组织中普遍表达,其中外套膜表达水平最高,在鳃中表达最低;在鳗弧菌刺激后6～24h,青蛤外套膜中mytimacin的表达量出现明显上调的趋势且与对照组差异显著(P<0.05),说明mytimacin抗菌肽基因在青蛤的免疫反应中具有重要作用。     

青蛤Kazal型丝氨酸蛋白酶抑制剂基因的克隆及其在组织间的表达分析

利用构建的SMART-cDNA文库及高通量测序方法,获得了青蛤Kazal家族丝氨酸蛋白酶抑制剂基因(Serine Protease Inhibitor,SPI)的全长序列,采用荧光定量PCR方法分析了SPI在青蛤各组织的表达情况,并在鳗弧菌胁迫下分析了SPI在青蛤血液中的时序表达关系。结果表明,青蛤SPI基因全长587 bp,CDS为67~520 bp,编码151个氨基酸,具有19个氨基酸的信号肽序列;荧光定量PCR结果显示,该基因在血液、肝脏、外套膜、鳃和闭壳肌等组织中表达差异明显,其中血液中表达水平最高,在闭壳肌中表达水平较低,其他组织表达量极少;在鳗弧菌刺激后3 h和48 h青蛤血液中SPI的表达量出现明显上调的趋势且与对照组有极显著性差异(P0.01),说明SPI基因在青蛤的免疫反应中具有重要的作用。     

文蛤SRBI基因克隆及其在不同壳色群体中的差异表达

为了研究SRBI基因的结构、功能以及在贝类壳色形成中的作用, 利用SMART RACE技术克隆得到文蛤(Meretrix meretrix) SRBI (Mm-SRBI)基因的全长序列, 并对其内含子特征及不同组织、不同壳色群体外套膜中的表达差异进行了分析。结果表明: Mm-SRBI基因cDNA全长1676 bp, 开放阅读框1515 bp, 编码504个氨基酸, 结构域预测发现有一个CD36结构域; 氨基酸序列比对发现, 与华贵栉孔扇贝的同源性最高(55%), 与其他物种的相似性在34%—40%, 表明该基因变异较大; 在Mm-SRBI基因中扩增出12个内含子, 均存在于开放阅读框中, 且都遵循GT-AG原则; 荧光定量PCR (qRT-PCR)结果表明, Mm-SRBI在闭壳肌、外套膜、斧足、鳃、内脏团和水管6个组织均有表达, 其中在外套膜中表达量显著高于其他组织(P<0.01), 这可能与外套膜中类胡萝卜素含量较高有关; 不同壳色群体外套膜中基因表达分析表明,Mm-SRBI在黑斑和红壳文蛤中的表达量显著高于白壳文蛤(P<0.05)。实验结果为文蛤壳色形成研究奠定了基础。     

日本血吸虫毛蚴对钉螺的钻穿及在螺体内的分布和移行

采自安徽省池的钉螺每粒感染５０只湖南株日本血吸虫毛后的组织学观察说明：毛蚴钻穿钉螺有从螺鳃部、头足总后有皮以及实质组织（外套膜、触角和阴茎）等三方面途径,其中以前二者尤为重要;毛蚴进入螺鳃丝后直接进入血液循环系统,从头足表皮进入的毛蚴,除了少数在钻穿部位附近滞留外,多数继续向头足部深层的肌肉和窦状组织间隙移行,以前头足窦、直肠和消化道外的组织间隙以及肾脏为主要的移行部位;从外套膜、触角、阴茎等部位     

江西玉山晚奥陶世三分贝类一新属--Zhuzhaiia

论文描述的三分贝类化石标本发现于江西省玉山县祝宅和马鞍山地区的三衢山组中,新种Zhuzhaiia transitense gen.et sp.nov,的特征是贝体大,两壳近等大,光滑;假铰合面大;腹内肌痕台悬空,无中板;背内肌痕台也悬空,腕腔中部有内向隆起,文中讨论该种的分类位置,根据假铰合面和肌痕台的特征,在总体上可以归入三分贝类,但发育了三分贝科没有的一些特征,如两壳近等大,肌痕台完全悬空,有简单的铰齿和铰窝,所以作者另立新科Zhuzhaiidae fam.nov.,Costitrimerella Rong et Li,1993属的一些特征,如其背壳内肌痕台前部悬空,无中板支持,似乎显示从三分贝科到新科的过渡性质,而新科在许多特征上也显示了从三分贝类到五房贝类的一些过渡性质。     

Silenites Coryell et Booth,1933(Ostracoda)的系统分类位置

本文记述介形类Silenites属的3新种和1未定种,标本采自山西太原西山七里沟上石炭统太原组。关于Silenites属的系统分类位置,迄今还未确定,鉴于当前标本所显示的闭壳肌痕系由众多痕斑聚集成圆形;铰合构造在大瓣上为槽,小瓣上为脊,且光滑无齿;壳面光滑无饰;壳体侧视近三角形,高大于长之半;左壳大于右壳,周缘超覆等特征,笔者认为,Silenites属应归入Bairdiocyprididae科(Shaver,1961)。     

两种软体动物神经系统一氧化氮合酶的组织化学定位

运用一氧化氮合酶(NOS)组织化学方法研究了软体动物门双壳纲种类中国蛤蜊和腹足纲种类嫁Qi神经系统中NOS阳性细胞以及阳性纤维的分布。结果表明：在蛤蜊脑神经节腹内侧,每侧约有10-15个细胞呈强NOS阳性反应,其突起也呈强阳性反应,并经脑足神经节进入足神经节的中央纤维网中;足神经节内只有2个细胞呈弱阳性反应,其突起较短,进入足神经节中央纤维网中,但足神经节中,来自脑神经节阳性细胞和外周神经系统的纤维大多呈NOS阳性反应;脏神经节的前内侧部和后外侧部各有一个阳性细胞团,其突起分别进入后闭壳肌水管后外套膜神经和脑脏神经索。脏神经节背侧小细胞层以及联系两侧小细胞层的纤维也呈NOS阳性反应。嫁Qi中枢神经系统各神经节中没有发现NOS阳性胞体存在;脑神经节、足神经节、侧神经节以及脑—侧、脑—足、侧—脏连索中均有反应程度不同的NOS阳性纤维,这些纤维均源于外周神经。与已研究的软体动物比较,嫁Qi和前鳃亚纲其它种类一样,神经系统中NO作为信息分子可能主要存在于感觉神经。而中国蛤蜊的神经系统中一氧化氮作为信息分子则可能参与更广泛的神经调节过程。     

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     

广西六景和刘家早泥盆世介形类中华豆石介族

报道广西六景和隆安刘家早泥盆世中华豆石介族１属、１亚属和２０种，其中包括９新种和７未定种。根据统计，莲花山组的中华豆石介族下垂“Ｖ”字型肌痕与闭壳肌痕的垂直高度之比值约为０．７０，而那高岭组的中华豆石介族下垂“Ｖ”字型肌痕与闭壳肌痕的垂直高度之比值约为０．７４。通过对中华豆石介族，特别是肌痕的研究认为，莲花山组可与云南曲靖西屯组对比。     

近江牡蛎HSP70基因对溶藻弧菌感染的反应

采用实时荧光定量RT-PCR方法,检测了注射溶藻弧菌(Vibiro alginolyticus)后近江牡蛎鳃,闭壳肌,消化腺,外套膜,心脏以及血细胞中HSP70基因的表达变化。结果显示近江牡蛎这五种器官组织中的HSP70基因表达量均出现显著性高表达,且在鳃、外套膜和血细胞中的HSP70基因表达变化规律表现为典型的时间依赖性。血细胞中,显著高表达的峰值出现在24h,至72h恢复到对照水平,高表达持续时间最长:鳃中表达峰值出现时间较早,在第3h,随后在第12h便恢复到对照水平;外套膜,消化腺以及心脏中的峰值分别出现在6h,6h和3h,而在闭壳肌组织中,没出现显著性高表达。由此可见,近江牡蛎HSP70s可能在机体抗菌免疫过程中起了重要作用。     

Structure and formation of the adventitious tube of the Japanese watering-pot shell Stirpulina ramosa (Bivalvia, Anomalodesmata, Clavagellidae) and a comparison with that of the Penicillidae

Abstract. Stirpulina ramosa is the only extant endobenthic representative of the Clavagellidae and is restricted to the waters of Japan. A single intact adventitious tube of this species has been obtained and its structure is described. The right valve is 16 mm long and located within the adventitious tube. It has an opisthodetic ligament located on resilifers. There are anterior and posterior adductor muscle scars, a thick pallial line, and pallial and pedal gape (right valve only) sinuses. The left shell valve is but 9 mm long and is united into the fabric of the adventitious tube via the intermediary of a shelly saddle. Internally, only the anterior adductor muscle scar and a small element of the pallial line scar are identifiable on the left valve. The posterior adductor and the rest of the pallial line scar (including a pallial sinus) are, remarkably, located on the adventitious tube beyond the shell valve margin. The adventitious tube of S. ramosa is formed in a manner wholly dissimilar from that of Brechites vaginiferus (Penicillidae). In B. vaginiferus, the tube is secreted as a single entity from the general outer mantle surface, including the siphons, covering the body. As a consequence, both shell valves are incorporated into the structure of the tube and the watering pot is bilaterally symmetrical. In S. ramosa, the tube and watering pot are secreted from the mantle margin and surface surrounding and extending from the left shell valve, so that only the left valve is incorporated into its structure. A dorsally derived mantle element is progressively extended over to the right side of the body, meeting a ventrally derived counterpart that passes beneath it, forming a pleat in the calcareous structure of the right side of the tube that they secrete. This pleat extends into the complex of watering‐pot tubules and forms the pedal gape. The watering pot is thus Ω shaped. The ventrally derived mantle element forms a sinusoidal crest on the right‐hand base of the watering pot, creating a pedal gape sinus scar on the right valve. The Clavagellidae radiated widely in the Mesozoic, leaving behind a rich fossil record for Stirpulina. Only S. ramosa, however, has survived until the present. In contrast, the Cenozoic Penicillidae has a poor fossil record, but there is a rich variety of extant endobenthic watering‐pot shells. It has been argued hitherto that the two families represent a remarkable example of convergent evolution. In view of the success of the Penicillidae and thus the endobenthic, tube‐dwelling lifestyle, however, it is hard to understand why Stirpulina has largely died out—even S. ramosa being known by but one or two specimens. A study of the anatomy of S. ramosa might one day answer this question.     

THE ADDUCTOR AND RETRACTOR MUSCLES OF THE VELIGER OF PECTEN MAXIMUS (L.) (BIVALVIA)

In Pecten maximus (L.), retractor and adductor muscles becomefunctional in the early veliger larva. The twelve-day-old veligerhas four pairs of velar retractors, three pairs of retractorsattached to the posterior body wall and an anterior adductor.The pediveliger has in addition, pedal retractor muscles anda posterior adductor. The retractors consist of striated muscle:the adductors have both smooth and striated portions. The retractorsattach near the hinge, branch to a greater or lesser extent,then attach to specific areas of the velum, posterior body walland foot. Some features of the branching and of the dispositionof points of attachment form a pattern which exhibits mirrorsymmetry about the plane between the two shell valves. Thispattern is characteristic of the species. It is deduced thatretraction and protraction of the velum result from co-ordinatedsequences of muscle contractions. ^*Present address: Forest Products Research Centre, P.O. Box1358, Boroko, Papua New Guinea. (Received 15 June 1984;     

Nuclear and cytosolic distribution of metallothionein in the blue mussel Mytilus edulis L

Four tissues from the blue mussel, Mytilus edulis L., were examined for the presence of nuclear metallothionein (MT), and the nuclear:cytosolic (N:C) MT ratios and nuclear MT:DNA ratios investigated. Gill, digestive gland, gonad and posterior adductor muscle tissues were dissected, homogenized and subjected to differential centrifugation in order to isolate the nuclear and cytosolic fractions, which were then analyzed for MT and DNA. MT was present in all samples of the nuclear fractions from all four tissues. The nuclear MT concentration was either lower or the same as the cytosolic MT concentration from the same tissue. The mean N:C MT ratio of the digestive gland was significantly lower than that of the gill. The mean nuclear MT:DNA ratio of the digestive gland was significantly higher than that of the gill and posterior adductor muscle. In addition to being the first report of nuclear MT in bivalves, we showed that N:C MT ratios and nuclear MT:DNA ratios differ among tissues of the same organism. This raises important questions concerning the regulation of nuclear MT concentrations and the role of nuclear MT in metal regulation and DNA protection.     

Assessment of the state of the Japanese scallopMizuhopecten yessoensis in Alekseeva Bight (Peter the Great Bay, Sea of Japan) based on morphological and biochemical parameters

The results of an integrated examination of the state of the scallopMizuhopecten yessoensis in Alekseeva Bight (Peter the Great Bay, Sea of Japan) are presented. In mollusks of different ages, shell height was measured; in animals of commercial size (over 100 mm), some size and weight characteristics (annual increment of shell and adductor muscle and soft tissue weight) were determined. The morphology of the digestive gland and gills was studied. In the adductor muscle and digestive gland, the concentration of heavy metals (HMs) (Hg, Cu, Zn, Mn, Pb, Cd, Ni, Co, and Cr) was determined. In the digestive gland, metallothionein and reduced glutathione concentration was also determined, as was the activity of glutathione-dependent enzymes (glutathione peroxidase and glutathione reductase). In scallops collected outside Alekseeva Bight, the linear growth rate and adductor muscle weight were on average 1.3 and 1.7 times greater, respectively, than in those collected in the bight. In scallop organs, numerous histomorphological alterations were revealed: digestive cell vacuolization and hemocyte infiltration of the digestive gland, hyperplasia and vacuolization of the respiratory epithelium, and connective tissue hypertrophy in gill filaments. The biochemical parameters of scallops from Alekseeva Bight differed substantially from those of mollusks collected outside the bight. We conclude that one of the factors negatively affecting the state of theM. yessoensis population in Alekseeva Bight is the contamination of the bight with HMs, especially mercury. This is consistent with the results of chemical analysis of bottom sediments and tissues of two mytilid species,Modiolus kurilensis andCrenomytilus grayanus, specimens of which were collected in the bight together with the scallops [3].     

New freshwater mussels (Bivalvia,Unionida) with potential trigonioidid and hyriid affinities from the Early Cretaceous of Brazil

Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed or splayed articulated valves, some of them potentially in life position, forming an autochthonous to parautochthonous assemblage. Monginellopsis bellaradiata nov. gen., nov. sp. shares key characters with the Trigonioidoidea: (i) the anterior pedal retractor muscle scar is clearly separated from the anterior adductor muscle scar; (ii) the shell has fold-like radial ribs on the posterior half; (iii) a right valve anterior tooth has a striated facet. Araripenaia elliptica nov. gen., nov. sp. is the most abundant and widely distributed unionid of the Crato Formation. Its ornament of anterior inverted V-shaped riblets, and central and posterior radial and sub-radial riblets resembles modern and fossil Hyriidae from the Americas, but also Trigonioidoidea from Eurasia. Its dentition of two smooth anterior pseudocardinals and two smooth posterior laterals in each valve provides no further clues for systematic assignment; muscle scars are not preserved. Assignment to the Hyriidae would make Araripenaia the oldest member of this family known from South America. Moreover, this bivalve assemblage of trigonioidoidids, hyriids, and previously reported silesunionoids suggests palaeobiogeographic links to other areas in both Gondwana and Laurasia.     

Growth and reproduction of the bay scallop, Argopecten irradians (Lamarck) at its southern distributional limit

Growth and reproduction in a Florida population of bay scallop, Argopecten irradians (Lamarck), existing at the southern limit of its distribution, was monitored over a 3-yr period. Somatic growth accompanied increasing water temperature between May and August, when maximum mantle, digestive gland, and adductor muscle weights and indexes were observed. From July through September, reproductive development was correlated with a decline in adductor muscle weight and index. Maximum gonad weight, gonad index, and oocyte diameter were found in late September and early October. Spawning commenced at this time in conjunction with decreasing water temperature.In comparison to more northern populations, the reproductive cycle of the Florida bay scallop occurs later in the year and is characterized by a higher gametogenic initiation temperature, a decreased maximum gonad index and decreased oocyte diameter, and a shift in reproductive energy resources from digestive gland (available food) to adductor muscle (pre-stored reserves). Increased metabolic rate associated with higher temperature and coupled with decreased food supply results in the Florida bay scallop having less energy available for reproduction, ultimately limiting its southern distribution.     

Sterol composition of gonad,muscle and digestive gland of Pecten maximus from Málaga (South Spain)

Sterol composition and content and their seasonal variations over 18 months were investigated in adductor muscle, digestive gland and gonads of Pecten maximus. Sterols were isolated by Silicagel 60 thin layer chromatography and identified by gas chromatography/mass spectrometry. Eleven sterols were identified, with cholesterol, brassicasterol, 24-methylenecholesterol and 22-trans-dehydrocholesterol being the principal components. The same sterols were found in all three tissues independent of season. The relative amounts of each sterol present in each tissue differed. Total sterol levels in gonad and muscle were higher than in digestive gland. Statistically significant differences (P<0.05) were found between the concentrations of each of the sterols isolated from the gonad or muscle and digestive gland. The seasonal variations in the sterol content of the gonad seem be related to the reproductive cycle, while the sterol content of the digestive gland appears to be linked to diet, mainly diatoms or dinoflagellates. The muscle sterol content showed minor changes throughout the year.     

Oxidative-stress: comparison of species specific and tissue specific effects in the marine bivalves Mytilus edulis (L.) and Dosinia lupinus (L.)

This study describes a novel approach to the objective of identifying a suitable biomarker of oxidative-stress in marine animals and evaluates an established assay under controlled experimental conditions in vivo and in vitro. Live animals and tissue homogenates of the euryoxic blue mussel Mytilus edulis (L.), and the stenoxic smooth artemis Dosinia lupinus (L.), were exposed to oxidative-stress generated using a 60Co gamma-radiation source. In live organisms, mortality-rates were significantly different between species. M. edulis showed zero mortality and D. lupinus 30% mortality over 18 h. Protein-carbonyl (PC=O) content was determined by colourimetric assay (total protein-carbonyl) or immunodetection (for individual proteins) in four tissue types: digestive gland, mantle, adductor muscle and foot. In tissue homogenates, digestive gland and adductor muscle of both species showed significant increases (greater for D. lupinus) in PC=O content following irradiation in vitro. All tissues from live animals (with the exception of M. edulis mantle and adductor muscle of D. lupinus which died under irradiation) showed significantly different levels of PC Os following irradiation; D. lupinus PC=O levels were increased whilst in M. edulis PC=O content decreased. In D. lupinus which died during irradiation, PC=O content was greater than in those D. lupinus which survived, particularly in the adductor muscle, the former were inceased by 74% above controls. The findings support the hypothesis that species-specific adaptations to euryoxic and stenoxic environments, and metabolic requirements of different tissues, should result in differing ROS defences.     

Musculature and Muscle Scars in the Cytherid Ostracode Cytheridea papillosa (Bosquet)

The intrinsic and extrinsic musles in Cytheridea papillosa are described and their function discussed. Special attention has been paid to the extrinsic muscles and the scars these muscles form on the valves. Two scars, close together, in the central area, earlier referred to as frontal or an-tennal scars, have muscular origin. The larger of these belongs to the carapax adductor system, and the name frontal adductor muscle scar is suggested for it. The smaller scar is associated with the mandible, whose muscle acts as an abductor. The name mandibular abductor muscle scar is suggested for it.     

Extraction and Identification of the Pigment in the Adductor Muscle Scar of Pacific Oyster Crassostrea gigas

In this study, UV (ultraviolet) and IR (infrared radiation) spectral analysis were integrated to identify the pigment in the adductor muscle scar of the Pacific oyster Crassostrea gigas. The pigment was extracted from the adductor muscle scars of cleaned oyster shells that were pulverized, hydrolyzed in hot hydrochloric acid, purified with diethyl ether, and dissolved in 0.01 mL/L NaOH. The maximum absorption of the pigment in the UV absorption spectrum within the range of 190–500 nm was observed between 210–220 nm. The UV absorbance decreased with increasing wavelength which was consistent with the UV spectral absorption characteristics of melanin. In addition, Fourier transform infrared spectroscopy scanning revealed characteristic absorption peaks that emerged near 3440 cm^-1 and 1630 cm^-1, which was consistent with infrared scanning features of eumelanin (a type of melanin). This study has demonstrated for the first time that the pigment in the adductor muscle scar of the Pacific oyster is melanin, hinting that the adductor muscle could be another organ pigmenting the mollusc shell with melanin other than mantle.