Cloning and expression patterns of two Smad genes during embryonic development and shell formation of the Pacific oyster Crassostrea gigas

Increasing evidence indicates that transforming growth factor β(TGF-P) signaling pathways play many important roles in the early development of mollusks.However,limited information is known concerning their detailed mechanisms.Here,we describe the identification,cloning and characterization of two Smad genes,the key components of TGF-P signaling pathways,from the Pacific oyster Crassostrea gigas.Sequence analysis of the two genes,designated as cgi-smad1/5/8 and cgi-smad4,revealed conserved functional characteristics.The two genes were widely expressed in embryos and larvae,suggesting multiple roles in the early development of C.gigas.The mRNA of the two genes aggregated in the D quadrant and cgi-smad4 was highly expressed on the dorsal side of the gastrula,indicating that TGF-P signaling pathways may be involved in dorsoventral patterning in C.gigas.Furthermore,high expression levels of the two genes in the shell fields of embryos at different stages suggested important roles for TGF-P signaling pathways in particular phases of shell development,including the formation of the initial shell field and the biomineralization of larval shells.The results of this study provide fundamental support for elucidating how TGF-P signaling pathways participate in the early development of bivalve mollusks,and suggest that further work is warranted to this end.     

深圳市潮间带动物体内的重金属含量

2005年12月和2006年5月调查了深圳海岸潮间带动物体内的重金属含量.结果表明,动物体内重金属Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Se、Mo、Pb、Cd、Sn、Sb、Ba和Hg的平均含量分别为0.63、9.24、137.22、0.13、1.46、97.36、283.77、1.96、0.49、0.27、0.68、0.62、0.28、0.01、1.23和0.01mg·kg-1(湿重).采用中国海岸带污染综合调查技术组推荐使用的海洋生物污染评价标准以及贾晓平等提出的污染评价标准参考值,结果表明深圳潮间带软体动物体内的Cu、Zn超标较为严重,其中牡蛎的Cu、Zn超幅分别达到5.27和9.05倍.所有样品中的Cr、Ni、Pb和Hg都没有超标,而As则全部超过人类食用限量标准,部分样品如疣荔枝螺Thais clavigera的超幅达5.63倍.分析表明,深圳市潮间带软体动物Cu含量超标源自珠江口、深圳湾及大鹏湾海水中的Cu超标,而所调查动物中Zn和As的超标原因有待进一步研究.     

黄土高原35万年来冬、夏季风变化周期的差异——陆生蜗牛化石的证据

针对我国北方风积黄土广泛分布、不同地点黄土-古土壤序列可准确对比和黄土沉积剩磁稳定等特征,通过对不同地壳块体上相同层位的黄土样品沉积剩磁方向的测定,进一步探讨了应用"虚磁极法"研究鄂尔多斯块体与相邻块体的相对运动的可能性.初步的研究结果显示:该方法有可能应用于块体相对运动的定量研究,并初步得到,在第四纪时期鄂尔多斯块体相对于邻近块体作逆时针转动,自2.5Ma B.P.以来相对秦岭块体的转动约为31.5°±11.4°,自1.17Ma B.P.以来相对西宁块体的转动约为29.8°±14.7°,自0.46Ma B.P.以来相对太行山块体的转动约为8.2°±5.8°,相对于西宁块体的转动约为10.5°±6.4°.本文还根据这些块体间相对转动的角度初步估算了鄂尔多斯块体与相邻块体之间的活动断裂带不同时期的水平位移总量.     

Zoogeography and paleozoology of leeches,molluscs, and amphibians in Western Bonneville Basin,Utah, USA

The artesian springs of Tule Valley are similar to those of adjacent Snake Valley and Fish Springs Flat based on conductivity and temperature. All three valleys support Ranidae amphibians and the leechErpobdella punctata. The artesian springs in Snake Valley and Fish Springs Flat contain six and two species of fish and contained up to 18 and 12 species of mollusk respectively, whereas Tule Valley artesian springs contain neither fish nor mollusks. The leechesHelobdella stagnalis, Glossiphonia complanata, andHaemopis grandis were found in Snake Valley whereasHelobdella triserialis, Theromyzon rude, andHaemopis marmorata were found in Tule Valley. These springs which were covered by Lake Bonneville to a depth of several hundred meters, 16 000 BP., became isolated after the paleolake desiccated 13 000 years BP. The marsh snailCatinella is found above the paleolake level in Snake and Tule Valley and has not penetrated to the valley floor habitats once covered by the paleolake, whereas another marsh snailOxyloma has penetrated into these habitats in Snake Valley. The leech and molluscan distributions in Tule, Snake and Fish Springs Valleys suggest that the paleolake did not allow for much movement among the valleys, and successful passive aerial transport has not occurred after the paleolake desiccation 13 000 years BP. Paleozoological models are proposed to explain the presence and absence of these species in Tule Valley. Both lateral movement (along paleolake shorelines) and vertical movement (to new habitats formed after the desiccation of the paleolake) by amphibians, mollusks and leeches is restricted in large terminal lakes and is species dependent in both spatial and temporal scales of the hydrological cycle.     

江苏省宜兴西溪、骆驼墩篮蚬与环棱螺研究

江苏宜兴西溪、骆驼墩篮蚬(Corbicula)与环棱螺(Bellamya)计有10种,其中篮蚬8种,环棱螺2种,属种虽然不多,但是个体数量极多。可分成4个组合类群:一是Corbicula fluminea-Corbicula largillierti组合。这个组合类群地质历程长,适应性强,个体数量多,分布广泛;最早发现于青海柴达木盆地第三系,代表古老类群。二是Corbicula obrutschewi-Corbicula takasaga组合,这个组合类群壳体较大,轮廓三角形,壳长略大于壳高;C. obrutschewi产于河北张家口岔道村附近的下更新统;C. takasaga发现于台湾新竹的上新统苗栗组;但在中、上更新统时期未发现本组合代表,可是到全新世时,宜兴的西溪、骆驼墩又出现本组合代表,似乎是返祖现象。三是Corbicula celsusapica-Corbicula yixingensis组合。本类群壳体中等大小,厚而膨凸,轮廓高圆三角形,壳高大于壳长,壳顶宽大而高耸,铰板宽,壳顶腔很深;Corbicula celsusapica发现于浙江湖州上更新统,C. yixingensis到目前仅见于宜兴。本组合为长江下游的宜兴和浙江湖州新生代晚期的特有种。四是Bellamya quadrata-Bellamya viviparoides组合。本组合在上更新统至现在的河流、湖泊均有,其中B. quadrata化石发现于江苏新沂上更新统,B. viviparoides化石发现于江苏句容上更新统下蜀组。     

Preliminary study of mollusk fossils in the Qinan Miocene loess-soil sequence in western Chinese Loess Plateau

The Qinan Miocene loess-soil sequence (~22―6.2 Ma)[1] discovered from the Gansu Group[2] several years ago extends the well-known Quaternary loess-soil sequence and the late Tertiary Red Clay se-quence of the Loess Plateau to early Miocene epoch. Most recently, the Dongwan late Miocene–Pliocene loess-soil sequence (~7.1―3.5 Ma)[3] further extends the upper limit of the reported Qinan Miocene loess-soil sequence into the Pliocene. These extensions have great potentials for the study o…     

几种软体动物对~14C-DDT和~14C─杀灭菊酯的积累和排泄

应用同位素示踪技术研究了几种软体动物：翡翠贻贝Pernaviridis、波纹巴非蛤Paphia（Paphia）undulata、凸加夫蛤Gafrariumtumidum、曲畸心蛤Anomalocardiaflexuosa、伊萨伯雪蛤Chione（Clausinella）isabellina、纵带滩栖螺Batillariazonalis和珠带拟蟹守螺Cerithideacingulata,对~14C－DDT和~14C－杀灭菊酯的积累和排泄。结果表明：~14C－DDT很快地在动物体中积累。翡翠贻贝和波纹巴非蛤积累DDT的能力最高,腹足类的纵带滩栖螺和珠带拟蟹守螺积累DDT的能力较差。~14C－DDT在动物中的分布具有器官特异性,在消化腺和鳃中分布最多,外套膜、足和水管次之,贝壳中的积累最少。DDT在波纹巴非蛤中的半衰期最长,除鳃以外,DDT在波纹巴非始的软组织中的半衰期在30d以上,提示波纹巴非蛤可能作为海区DDT污染的指示生物。杀灭菊酯在软体动物中的积累和排泄类似DDT,但其浓集系数和半衰期均远远小于DDT。     

中国梭螺科一新记录属

本研究记述了采集自海南陵水海域的梭螺科(Ovulidae)一新记录属：舟梭螺属(Naviculavolva)及一新记录种：折唇舟梭螺(N.deflexa),对标本进行了形态描述并附标本照,且通过比对样品的COⅠ基因序列证实了形态鉴定的准确性。本研究为梭螺科分类与研究提供参考资料,丰富了我国海域梭螺科物种的多样性,并使得折唇舟梭螺的分布范围延伸至海南省海域。     

海产贝类体内类胡萝卜素的研究进展

类胡萝卜素是一类脂溶性的大分子量的有机化合物,在染色、医药、食品等行业中具有很高的应用价值.类胡萝卜素也广泛地存在于海产贝类体内.本文详细综述了国内外海产贝类体内类胡萝卜素的来源、种类和含量、功能及吸收代谢方面的研究状况,为今后的研究提供参考.