马氏珠母贝肉酶解产物的抗酒精性肝损伤作用

为探究马氏珠母贝肉酶解产物(Enzymatic hydrolysate from Pinctada martensii,EP)对酒精性肝损伤(Alcoholic liver damage,ALD)的保护作用,该研究将EP超滤分级为截留分子量>10 kD(EP-Ⅰ)、3~10 kD(EP-Ⅱ)和<3 kD(EP-Ⅲ)3个组分,检测其体外抗肝损伤活性及对ALD小鼠肝保护作用的影响。体外试验结果显示,EP-Ⅲ可显著激活体外乙醇脱氢酶(ADH)活性(P<0.01),3个超滤组分均具有一定的体外抗氧化能力且EP-Ⅲ>EP-Ⅱ>EP-Ⅰ;动物试验结果显示,与模型对照组相比,各超滤组分均能够显著降低小鼠血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)活力、小鼠肝脏指数及肝脏中丙二醛(MDA)和甘油三酯(TG)含量,同时显著增强小鼠肝脏中超氧化物歧化酶(SOD)、乙醇脱氢酶(ADH)和乙醛脱氢酶(ALDH)活力,提高肝脏中的谷胱甘肽(GSH)含量。综上,马氏珠母贝肉酶解超滤组分对急性ALD具有一定的辅助保护作用,其中EP-Ⅲ的保护作用效果最佳,其机制可能与加快机体乙醇代谢和减缓乙醇对机体造成的氧化损伤相关。     

不同运输条件对合浦珠母贝稚贝存活比较

比较运输方式及环境温度对合浦珠母贝稚贝运输中的存活影响,从而为稚贝运输过程中的运输方式、环境温度及运输时间的把握提供借鉴和参考。以3月龄稚贝为实验材料,运用无水干露、加水淹没及包装充氧等3种方式,分别在环境温度为5、13、21和29℃下模拟运输。每隔3 h从每组运输条件下取出1组实验贝,转移到正常养殖环境下暂养恢复,经48 h后统计其存活率。对运输时间与存活率之间进行非线性参数曲线拟合,计算每组运输条件下的致死时间(T_0)、半致死时间(T_(0.5))及全致死时间(T_1);运用双因素方差分析,Duncan氏方法比较3种运输方式及4种环境温度间的均值。结果显示:包装充氧优于其他两种运输方式,而加水淹没又优于无水干露;温度为13℃和21℃时优于其他2个环境温度,环境温度为17.60～20.05℃是稚贝运输的最佳温度。     

Phenotypic indicators for cultured pearl size improvement in the black‐lipped pearl oyster (Pinctada margaritifera): towards selection for the recipient growth performance

The black‐lipped pearl oyster, Pinctada margaritifera, is the most important farmed species in French Polynesia and the basis of the most valuable export industry. Mass production of black pearls relies on a surgical operation requiring tissue from a donor pearl oyster to be grafted, together with a nucleus made of shell, into the gonad of a recipient oyster. Improving pearl size through family selection remains one of the main challenges for future aquaculture development. This study analyses the relative contribution of donor and recipient oysters to pearl size. To this end, hatchery‐produced donor oysters of two batches, large and small (based on shell height), were used to supply grafts for recipients, which were then monitored individually for their growth performance by recording shell height, width, and thickness, and total live weight (flesh + shells) every 6 months (four biometric measurement times) over 20 months of culture. Pearls issued from the two batches of donors showed no significant differences in nacre weight or thickness. In contrast, recipient oyster shell height and total weight were increasingly positively correlated with these pearl size parameters over the culture period, becoming significant at 8 months post‐grafting. Potential therefore exists to use shell height and oyster weight as phenotypic indicators for selective breeding of recipient oysters with high growth performance to increase pearl size in P. margaritifera.     

基于3种线粒体基因的珠母贝属系统进化关系

为了研究珠母贝属的分类地位和系统演化情况,通过聚合酶链式反应技术(PCR)扩增并直接测序出雷州半岛珠母贝属中的马氏珠母贝、大珠母贝、珠母贝、斑珠母贝和黑珠母贝的3种线粒体基因(12S r RNA、16S r RNA和COⅠ)部分序列,分析其碱基组成和种间遗传距离。同时结合Gen Bank上发表的白珠母贝序列,构建珠母贝属的分子系统树。结果显示,5种珍珠贝的3种基因部分序列碱基AT含量大于GC含量,与其他无脊椎动物线粒体DNA序列基本一致,序列都处于高度饱和的状态。系统分析显示,构建的分子系统树与传统的形态分类基本一致。在黑珠母贝和白珠母贝亲缘关系上,3种线粒体DNA片段在碱基组成、种间遗传距离和系统进化树上都显示黑珠母贝和白珠母贝非常相近,可以认为是同一种中的2个亚种。在斑珠母贝的亲缘关系上,系统分析显示斑珠母贝与黑珠母贝和白珠母贝更为接近。研究表明,大珠母贝和珠母贝在系统进化中较早的分离出来,是一个比较原始的种类。3种分子标记对马氏珠母贝亲缘关系分析上存在一定差异,根据现有的数据尚不足以得出结论,需进一步做分子系统研究并结合形态特征和解剖结构进行分析。     

Pearl grafting: Tracking the biological origin of nuclei by straightforward immunological methods

French Polynesia is renowned for the production of Tahitian black pearl. These gems are obtained by grafting a nucleus into the gonad of a receiving oyster together with a graft, i.e. a small section of mantle tissue of a donor oyster. This procedure initiates the formation of a pearl sack around the nucleus, and subsequently, the deposition of concentric layers of nacre. The nucleus plays a key‐role in pearl formation and its characteristics influence markedly the quality of the final product. As it is manufactured from mollusc shells, it contains a small percentage of organics. In the present paper, we used a set of biochemical techniques to characterize and compare the organic matrices from two types of nuclei that are currently used in French Polynesia: that from the freshwater mussel Amblema sp., and that from the pearl oyster Pinctada sp. To this end, we extracted the matrices from nuclei and performed FT‐IR, monodimensional electrophoresis, and enzyme‐linked immuno‐sorbent assay (ELISA). Our data show that the matrix associated with Amblema nuclei has a very different biochemical signature from that of Pinctada nuclei, a fact that may explain the improved tolerance of grafted oysters to nuclei of Pinctada origin. In the absence of complex physical methods of investigation, simple immunological techniques and FT‐IR performed on the extracted organic matrix are extremely reliable and effective for discriminating nuclei from these two sources. We assert that such techniques can be used as a diagnostic test to track unambiguously the biological origin of nuclei to avoid fraud.     

合浦珠母贝表皮生长因子样(EGF-like)基因的克隆与表达分析

为探究表皮生长因子(epidermal growth factor,EGF)在合浦珠母贝幼体发育以及组织生长过程中的作用,实验通过RACE技术克隆了合浦珠母贝EGF-like基因并做了相应的表达分析。实验结果获得cDNA全长序列4 107 bp,命名为Pf-egf1,开放阅读框(ORF)702 bp,编码234个氨基酸,包含一个信号肽序列和一个跨膜结构域,功能结构域分析发现Pf-egf1具有一个EGF-like结构域,有6个半胱氨酸残基,由3个二硫键维持,是表皮生长因子家族及其相关蛋白的特征结构域,但其余序列与现有相关基因序列差异较大,推测可能是一个新的EGF-like基因。表达结果显示,Pf-egf1 mRNA在合浦珠母贝外套膜、闭壳肌、鳃、肝胰腺、珍珠囊、肠和性腺中均有表达,在肠中的表达显著高于其他组织;在合浦珠母贝幼体发育的担轮期、D型期、壳顶期、眼点期和变态期的表达呈现逐渐升高的趋势,并且其在变态期的表达量极显著地高于其他时期。上述结果表明,Pf-egf1基因可能在合浦珠母贝肠道修复和幼虫变态发育阶段起着重要作用,为进一步开展育珠与生长调控奠定了基础。     

Spat availability of commercial bivalve species recruited on artificial collectors from the northern Gulf of California. Seasonal changes in species composition

This study reports a year‐round recruitment of spat of four commercial bivalve species; Pteria sterna, Euvola vogdesi, Pinctada mazatlanica and Pinna rugosa collected in the region of Puerto Peñasco, north‐eastern coast of the Gulf of California. Bimonthly recruitment of commercial bivalve spat on netlon^® collectors was evaluated for six sites from June 2007 to August 2008. To describe spat recruitment abundances with environmental parameters, sea surface temperature (°C) and surface chlorophyll a concentration (mg m^?3) were characterized by means of monthly Aqua/MODIS satellite data. For each species a repeated measures anova was used to evaluate differences in the number of spat between months, sites and depths. Maximum sea surface temperature was recorded in August–September (~31.5°C) and the minimum in January–February (~15°C), while the minimum surface chlorophyll a was observed in June–September (mean range = 1.5–2 mg m^?3) and the maximum in January–March (mean range = 2–5 mg m^?3). Spat recruitment showed distinct patterns; P. sterna can be characterized as having a Winter–Spring pattern, E. vogdesi a winter pattern, while P. mazatlanica and P. rugosa a summer spat recruitment pattern. This information constitutes part of the fundamental data needed for the development of aquaculture and conservation initiatives in the region based on wild spat supply.     

Comparison of harvested rate and nacre deposition parameters between cultured pearls issued from initial graft and second nucleus insertion in P. margaritifera

Cultured pearls produced with Pinctada margaritifera, using the surgreffe method (implantation of a second nucleus following pearl harvest) were studied for the first time to: (1) examine family effect on nacre thickness, nacre weight and nacre deposition speed and (2) compare variation in these three traits with that obtained from the cultured pearls previously harvested after the corresponding initial grafts. A surgreffe experiment using 783 recipient oysters was realized in Rangiroa atoll (French Polynesia). After 24 months of culture, 389 cultured pearls were harvested. Significant donor family effect was found for the harvested pearl rate from surgreffe (P = 0.046). Highly significant donor family effect was recorded for nacre thickness (P = 0.004). Very highly significant donor family effects were recorded for nacre weight and nacre deposition speed (P < 0.0001). Comparison between surgreffe and initial graft showed: (1) no significant effect for the average cultured pearl rate harvested (P = 0.052) and average cultured pearl nacre deposition speed (P = 0.622) and (2) very highly significant differences (P < 0.0001) for the average cultured pearl nacre thickness and nacre weight. This study highlighted three major implications for pearl industry management: (1) donor family effect was maintained from initial graft to surgreffe, for nacre thickness, weight and deposition speed, (2) the persistence of the pearl sac metabolic activity over three years of culture and (3) the relation between harvested pearl rate and the size of the nucleus inserted in the pearl sac.     

珠母贝糖胺聚糖的纯化及其化学性质

珠母贝糖胺聚糖粗制品经吸附、等电点沉淀、醇沉、溴化十六浣基三甲铵（ＣＴＡＢ）络合等进行分离纯化，得一糖胺聚糖级分。经醋酸纤维素薄膜电泳显示为单一区带。化学组成分析表明：该级分氨基已糖含量较高（７１．３％），其中以氨基半乳糖为（５９％），含量少量的乙糖醛酸，含硫酸基、半乳糖、岩藻糖。元素分析表明其碳、氢、氮、硫的含量分别为３７．７％、５．８％、３．０％。对级分的残余氨基酸分析表明，８４．２％氨基酸已     

马氏珠母贝肉的营养成分及其游离氨基酸组成

对马氏珠母贝肉的营养成分及游离氨基酸组成进行了较系统的食品化学特性研究，结果表明：马氏珠母贝含粗蛋白７４．９％（干基），蛋白质的氨基酸组成中，富含Ｇｌｕ（２．２１％）、Ａｓｐ（１．４５）、Ｇｌｙ（１．０１％）等呈味氨基酸；蛋白质营养价高，氨基酸价为８２，第一限制氨基酸是含硫氨基酸（１９７３年（ＦＡＯ／ＷＨＯ标准）；无机盐含量丰富，尤其是微量元素Ｚｎ和Ｓｅ；游离氨基酸中，牛磺酸含量最高达１．３８％，