RAPD标记在大连湾牡蛎种群研究中的应用

对四个不同地点（莱州,荣成,青岛和日照）的大连湾牡蛎（Ｃｒａｓｏｓｔｒｅａｔａｌｉｅｎｗｈａｎｅｎｓｉｓ）进行了ＲＡＰＤ分析,结果表明相邻两地种群的遗传距离不明显。地理相距越远,遗传距离越大。莱州种群中具有ＯＰＫ１１—６８５标记,日照种群具有ＯＰＫ１１—７８０标记。上述两地之间的青岛和荣成种群中,６２．５％的个体同时具有这两个标记;只有２０％的个体为ＯＰＫ—７８０标记。莱州和日照种群间的基因流动有一定的局限性,而位于这两地之间的种群存在明显的基因流动现象     

长牡蛎二倍体和三倍体生殖腺发育的组织学观察

对长牡蛎二倍体和三倍体生殖腺涂片检查结果表明,三倍体生殖腺发育较二倍体差,三倍体成熟卵母细胞和细胞核的体积分别是二倍体的１．６４和１．４４倍。组织切片检查结果,二倍体生殖腺发育正常,三倍体生殖腺发育受阻,大部分停留在增殖期的休止期,一部分虽发育至生长期和成熟期,但与同一发育期一二倍体比较,生殖腺发育差。三倍体雌性生殖腺发育较雌性好,三倍体雌雄性比为２．６２：１,在所取的样品中到３个雌雄同体个体。     

太平洋牡蛎受精过程中的精核扩散与成熟分裂

光镜下观察了太平洋牡蛎受精过程中的原核形成和成熟分裂。受精前,卵子处于第一次成熟分裂前期（即生发泡阶段）。精子入卵后开始进行成熟分裂,过程如下：（1）生发泡破裂前精核只进行轻微增大。（2）生发泡破裂,精核迅速去致密,体积迅速增大。（3）第一次成熟分裂结束,精核扩散速度减慢,核内染色体致密环状结构。（4）第二次成熟分裂结束,精核膨胀到最大程度。（5）两性原核形成,准备进行第一次卵裂。在整个受精过程中,核仁一直存在,其体积逐渐减小;有多精入卵并有多个精原核同时形成的现象。     

几种化学物质对两种牡蛎幼虫附着和变态的诱导

本文研究5种神经递质和1种神经肽对两种牡蛎幼虫附着和变态的诱导效应。结果表明：L－多巴对牡蛎幼虫附着行为的诱导快速而有效，浓度10μmol/dm^3，2h内有附着行为的幼虫约占50％，并使之正常变态，肾上腺素、去甲肾上腺素和L－多巴均能有效地诱导两种牡蛎幼虫变态，它们的最适诱导浓度分别为50、50和5μmol/dm^3，诱导变态率分别达97．1％、90．6％和70．5％（长牡蛎），74．9％、74．3％和37．2％（僧帽牡蛎）；多巴胺的诱导变态效果不显著，而γ－氨基丁酸和5－羟色胺不能有效诱导变态。两种牡蛎幼虫对上述有效诱导药物的反应，长牡蛎优于僧帽牡蛎。肾上腺素诱导长牡蛎，最适处理时机在眼点幼虫后期，持续处理时间为2h之内。     

近江牡蛎核糖体DNA片段基因序列及其分子分类研究

本文应用分子系统发育学的方法,以“白蚝”和“赤蚝”的18SrDNA、ITS1和ITS2片段序列信息为分子标记,对它们的分类地位进行了探讨.综合上述3种分子标记的分析结果,初步认为“白蚝”应属于近江牡蛎,而“赤蚝”可能不属于近江牡蛎.     

环渤海潮间带长牡蛎微塑料富集特征研究

微塑料是指最大粒径小于5 mm的塑料微粒,近年来其污染问题受到广泛的关注。2017年6月,在环渤海潮间带9个站位采集了野生长牡蛎(Crassostrea gigas)样品,通过组织消解、滤膜分离和显微镜检筛分微塑料样品,并利用显微傅里叶变换红外光谱仪(μ-FT-IR)对其化学成分进行分析。结果表明,环渤海潮间带长牡蛎体内的微塑料摄入率为73.91%～95.65%;微塑料平均丰度为2.03个/个体,每克生物组织平均丰度为0.89个。长牡蛎体内的微塑料形状以纤维类最多,所占比例为67.06%,其次为碎片类,薄膜和颗粒类所占比例较少。微塑料颜色以蓝色居多,其次为白色。长牡蛎体内粒径小于500μm的微塑料所占比例最高,其次为粒径500～1 000μm的微塑料。微塑料化学成分包括人造纤维、聚乙烯、聚对苯二甲酸乙二醇酯、聚丙烯、聚酰胺、聚苯乙烯等6种类型,其中人造纤维所占比例高达50.00%。以上结果表明,环渤海潮间带长牡蛎体内均存在一定的微塑料富集;与国内外其它研究相比,整体处于中等偏下水平;港口等站位的长牡蛎体内的微塑料丰度较高,而自然保护区站位的长牡蛎体内的微塑料丰度较低,表明微塑料污染与人类活动频繁程度密切相关。     

钦州湾海水和香港牡蛎体内脂溶性贝类毒素污染特征

近年中国沿海普遍受到脂溶性贝类毒素(lipophilic shellfish toxins,LSTs)的污染。钦州湾是国内外闻名的牡蛎养殖基地,目前仍不了解该海域海水和主要养殖品种香港牡蛎(Crassostrea hongkongensis)沾染LSTs毒素情况与食用安全性。本文于2015年10月至2016年9月,在钦州湾香港牡蛎养殖区海水交换口处,通过固相吸附毒素跟踪技术(solid phase adsorption toxin tracking,SPATT)吸附收集海水中的脂溶性贝类毒素,同时每月采集香港牡蛎样品,应用液相色谱串联质谱法分析海水和香港牡蛎体内的LSTs毒素含量与组成,并对香港牡蛎食用安全性进行评估。结果表明:(1)海水共检出GYM、OA和PTX2三种组分,平均浓度分别为0.44、14.20和1.67μg/(kg resin·30d)。香港牡蛎共检出DTX2、GYM、SPX1、Homo-YTX四种组分,其中Homo-YTX为定性结果, DTX2、GYM、SPX1三者平均浓度分别为0.95、18.86和0.95μg/kg。(2) GYM毒素均值在海水中和香港牡蛎体内含量变化趋势呈正相关,Pearson相关系数为0.70;OAs毒素在海水中和香港牡蛎体内变化趋势类似, Pearson相关系数为0.35。(3)毒素存在一定季节变化。海水OA和PTX2夏季高,其他季节低,均值最高值分别发生在7月和6月;香港牡蛎体内GYM冬季和夏季较高,DTX2春季和夏季较高;但海水中的GYM和香港牡蛎体内的SPX1全年变化均不明显。总体而言,钦州湾海水和香港牡蛎已受到多个LSTs毒素组分污染,海水LSTs毒素含量较国内其他海域低,参考欧盟LSTs毒素标准,本海域的香港牡蛎脂溶性贝类毒素仍未超标,可放心食用。     

黄河口与长江口近江牡蛎的比较转录组分析

为进一步开发近江牡蛎Crassostreaariakensis的基因资源,探究黄河口与长江口近江牡蛎的遗传差异,采用Illumina HiSeq 4000测序平台对东营垦利和南通海门的近江牡蛎进行高通量转录组测序。对测序数据进行拼接后分别得到83680条和71269条unigene,并对unigene进行了基因功能注释和正选择基因的富集分析。结果表明,同源基因经筛选得到正选择基因259个,GO (Gene Ontology)功能分析中共涉及到967个相关功能类别,其中有关到生物学过程的分类条目占比最多,为590项。总体上看,与细胞器、代谢过程、结合以及催化活性相关的类别占主导地位。KEGG( Kyoto Encyclopedia of Genes and Genomes)富集分析表明,共涉及48个代谢通路,其中与核糖体、细胞凋亡相关的通路占比最大。上述结果不仅加深了对黄河口以及长江口近江牡蛎基因表达水平差异的认识,同时也为今后进行近江牡蛎各类遗传学分析和一些关键基因的克隆以及具体功能分析提供了基础数据。     

Cellular responses of oysters, Crassostrea virginica, to metal-contaminated sediments

Elevation of metal concentrations in coastal environments associated with anthropogenic enrichment pose a significant threat to estuarine organisms. The purpose of this study was to evaluate the relationships between cellular responses that may be potentially valuable as indicators of chronic stress and metal-contaminated sediments. For these studies, hatchery-reared juvenile oysters were deployed in situ at 15 sites for approximately 1 month around Charleston Harbor, SC. The effects on lysosomal destabilization and glutathione concentrations were determined; and the relationships between the cellular responses and sediment metal concentrations were described. Both single metal and multiple metal parameters (based on total metal concentrations, aluminum normalizations, and summed sediment quality guidelines) were considered. Generally, significant correlations were observed for individual metal analytes and multiple metal parameters. Since many of the individual metal analytes covary, the responses may reflect overall contaminant loading rather than responses to individual metals. Methods for estimating overall contaminant loading based on multiple analytes provide a more realistic estimate of potential adverse effects.     

The Role of Suspended Oyster Culture on Nitrogen Cycle in Hiroshima Bay

The predominance of bivalves affects the cycle of materials in the coastal ecosystem. In the present study, the role of suspended oyster culture on the nitrogen cycle was demonstrated for the northern Hiroshima Bay. The nitrogen cycle was considered as two systems, (1) the primary production (PP) system and (2) the oyster culture (OC) system. The results show that about 26% of N productivity was supplied to process by cultured oysters in the OC system. This process varies seasonally due to the seasonal variations of PON, physiological activities and biomass of oysters. The N processing rates were found to be high in summer and low in winter. The biodeposition and excretion of N in the OC system are 3.0 and 2.1 ton N d^–1, while the natural sedimentation rate and N regeneration in the PP system are 8.3 and 18.0 ton N d^–1, which indicates that the PP system is a major system regenerating N in the water column. The release of total dissolved N from the bottom to the water column is about 8.3 ton N d^–1. The amount of N harvested as oyster product was about 1.3 ton N d^–1, which is about 10% of daily N loading in north Hiroshima Bay. According to the N cycle developed in the present study, the results suggest the significant role of suspended oyster culture on the nitrogen cycle in Hiroshima Bay. In addition, our results indicate that oyster production was efficiently harvested, suggesting that oyster culture could probably be used as a tool to remove N from Hiroshima Bay.