大珠母贝两个野生群体遗传多样性的微卫星分析

利用6对微卫星DNA分子标记对三亚和北海的大珠母贝群体进行遗传多样性分析。结果表明,两个群体的平均等位基因数A分别为10．5和9．7,平均有效等位基因数N。为7．0和6．3,平均观察杂合度Ho为0．588和0．445,平均期望杂合度Hc为0．859和0．828,平均多态信息含量PIC为0．853和0．796;卡方检验发现只有位点Pmx＋022、Pmx16—41和Pmxl6—23在三亚种群中Har—dy—Weinberg平衡偏离不显著（P〉O．05）,其他位点在两个种群都有不同程度的偏离。     

马氏珠母贝4个壳色选育系F1遗传结构的AFLP分析

本研究从湛江流沙港马氏珠母贝养殖群体中挑选不同壳色个体为亲本,共构建了黑（BS）、红（RS）、黄（YS）和白壳色（WS）4个壳色选系F1,然后分别在4个壳色选育系F,中随机取样,利用3对AFLP引物分析其遗传结构与遗传分化。结果表明,每对引物的扩增位点数在104～109之间,共得到331个扩增位点;BS、RS、YS和WS壳色选系F1的多态位点比例分别为49．2％、49．5％、51．6％和63．4％,Shannon’s多样性指数分别为0．1884、0．1886、0．1896和0．1954,4个壳色选育系F1的遗传分化系数（Fst）为0．1972。本研究说明经过一代壳色纯化4个壳色选育系F1出现显著遗传分化,也为马氏珠母贝壳色系选育或选育系间杂交提供了参考依据。     

Effects of glycopeptides on development,growth and non‐specific immunity of pearl oyster Pinctada fucata (Gould)

The effects of glycopeptides, prepared from pearl oyster Pinctada fucata, on embryonic development, larval and juvenile growth and adult non‐specific immunity of P. fucata were investigated in this study. Glycopeptides had a pronounced stimulatory effect on embryonic development and larval and juvenile growth of P. fucata. enhancing with increased glycopeptide concentrations. All of haemocytes, phagocytosis, aggregation, serum microbiostatic activity and bacteriocidal activity all showed significant increases after 60‐day feeding, relative to unfed controls. The major conclusion is that glycopeptides had a pronounced stimulatory effect on the non‐specific immunity of pearl oysters.     

Gametogenic cycle of the transplanted-cultured pearl oyster, Pinctada fucata martensii (Bivalvia: Pteriidae) in Korea

The gonadal development and gametogenic cycle of transplanted-cultured pearl oyster, Pinctada fucata martensii, were investigated using individuals collected monthly from Tong-Young along the south coast of Korea from October 2000 to September 2001. The result of monthly change of condition index was similar to tissue weight rate. The highest value was observed in June and the lowest value was observed in November. The gonad of the pearl oyster was located around the digestive diverticula. The ripe testis was milky white while the ovary was light brown. The spawning period of the pearl oyster extended from April to August, with a peak between June and July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (November to February), growing stage (January to March), mature stage (March and April), spawning stage (April to August) and resting stage (September to November).     

马氏珠母贝外套膜不同区域基因组DNA甲基化MSAP分析

通过甲基化敏感多态性扩增(methylation-sensitive amplification polymorphism,MSAP)技术,检测马氏珠母贝(Pinctada martensii)外套膜的边缘膜区(mantle edge,Me)、套膜区(mantle pallial,Mp)和中央膜区(mantle central,Mc)的基因组DNA甲基化修饰水平;回收具特异性的清晰甲基化修饰片段进行测序、比对分析并筛选基因;利用荧光定量PCR对筛选基因进行定量分析。结果显示:(1)利用15对引物进行扩增实验,平均每个个体外套膜3个区域能够产生(1163.25±124.34)条清晰可辨的条带,其中Me、Mp和Mc分别得到(401.00±40.37)条、(380.63±52.39)条和(381.63±53.57)条扩增条带,各组织甲基化总条数差异不显著(P0.05);Me、Mp和Mc的基因组甲基化水平分别为(17.07±2.19)%、(15.48±2.34)%和(19.61±2.88)%,Mc和Mp具有显著性差异(P0.05);组织间的基因组甲基化水平由高到低排列依次是McMeMp。(2)对特异性片段进行回收、测序后,经在线及本地Blast比对,得到8条存在甲基化修饰的基因序列,其中3条有同源序列,基因注释为40S核糖体蛋白SA(40S ribosomal protein SA)、iHog(interference hedgehog)、锌指蛋白(zinc finger protein castor)。iHog仅在中央膜上具有全甲基化修饰,且E值较低,为筛选的目的基因。(3)荧光定量结果表明iHog在Me、Mp和Mc中均有表达,以Me表达量最高,Mc表达量最低,差异显著(P0.05)。我们推测iHog的DNA序列的甲基化修饰抑制了该基因在Mc组织中的表达。综上研究结果表明,马氏珠母贝外套膜3个区域的甲基化修饰水平不一,且DNA甲基化在基因表达调控中具有作用,这对深入研究珍珠贝生物矿化和免疫反应机制具有一定的参考意义。     

Is pearl colour produced from Pinctada margaritifera predictable through shell phenotypes and rearing environments selections?

The black‐lipped pearl oyster, Pinctada margaritifera, is the most important farmed mollusc species in French Polynesia. Donor oyster selection among wild P. margaritifera individuals, chosen according to their inner shell colour, makes it possible to obtain the broadest range of cultured pearl colours of any species. This study demonstrates the relative influence of using black [B] or red [R] outer shell phenotypes, combined with green [G] or yellow [Y] inner shell phenotypes, on pearl darkness level, colour categories and lustre. A large scale grafting experiment was designed and carried out over five grow‐out locations, covering three archipelagos: Tuamotus, Society and Gambier. Results revealed that the [B + G] phenotypes may be used as donors to produce dark green pearl, which suit the demands of the Asian market; whereas, phenotypes incorporating [R] and/or [Y] phenotypes may be used to obtain multicolour pearls of medium/light darkness, which suit the demands of the European market. From an environmental point of view, the 1) [B] phenotype showed no significant variation for light and other pearl colour production, and 2) [Y] phenotype produced both the same rate of pearl darkness level and green colour pearls whatever the grow‐out location. A classification tree model was built to predict, according to shell phenotype and culture location, the colour and darkness level of harvested pearls. Lustre was shown to be more influenced by the environment than by phenotype. These results should be taken into account in pearl farm production management and in selective breeding programmes.     

Feeding the pearl oyster Pinctada margaritifera during reproductive conditioning

This study aimed to model the food intake of P. margaritifera to examine the relationship between food level and reproductive activity. The effect of microalgae concentration on ingestion rate and assimilation efficiency was studied over a broad concentration range, using a mixture of Isochrysis galbana and Chaetoceros gracilis. Reproductive effort was assessed using three microalgae concentrations of 0.5, 7 and 18 cell μL^?1. Reproductive status was assessed by gonad development index (GDI) – the ratio of the gonad surface to the visceral mass surface – and histological analysis of the gonad based on the presence (continuous or discontinuous) or the absence of gonial cells (GC). Ingestion is a saturating function of seston concentration for bivalves modelled with an adapted Michaelis‐Menten function. The maximum ingestion rate of P. margaritifera adults was 193.50 × 10⁶ cell h^?1 g^?1 dw and the half saturation coefficient was 15 cell μL^?1. The concentration of 18 cell μL^?1, supplied for 45 days, induced a significantly higher GDI than the other treatments. GC decreased significantly and even stopped when pearl oysters were under‐fed, suggesting that the mitotic process of the germinal stem cells was altered. Differentiation of germinal stem cells therefore appears to be controlled by food availability.     

马氏珠母贝不同组织同工酶的比较

采用聚丙烯酰酰胺凝胶水平平板电泳技术,研究了马氏珠母贝的８种组织７种同工酶的酶谱表型,结果表明：所测组织中未检出α－磷酸甘油脱氢酶（α－ＧＰＤＨ）和醇脱氢酶（ＡＤＨ）,乳酸脱氢酶（ＬＤＨ）只在肝脏一条微弱谱带,苹果酸脱氢酶（ＭＤＨ）、苹果酸酶（ＭＥ）和超氧化物岐化酶（ＳＯＤ）部分组织间有显著差异,而酯酶（ＥＳＴ）则具有明显的组织特异性。     

ECONOMIC FEASIBILITY OF SMALL-SCALE BLACK-LIPPED PEARL OYSTER (PINCTADA MARGARETIFERA) PEARL FARMING IN THE CENTRAL PACIFIC

ABSTRACT

This work provides an analysis of the economic feasibility of one of many small-scale aquaculture operations being considered, black pearl oyster farms, as one type of supplemental economic activity for outer island communities in the Central Pacific. Specifically, projections of financial performance of a small-scale 25,000 seeded pearl oyster farm using the Tahitian long-line method are being conducted. Estimates of initial capital investment and annual operating costs are being formulated, an annual cash flow and enterprise budget are being developed. Results show that initial capital investment is $202,076. Annual operating expenses are $293,726 during full operation. The largest costs contributing to annual operating expenses are seeding (46%), labor including farm owner's opportunity cost (24%), and depreciation (9%). The base model presented in this work suggests profitability over a 20-year horizon.

Net returns over a 20-year farm horizon based on an 8% discount rate indicate a positive NPV of $ 102945. Sensitivity analysis on profit due to the variability of market price, survival, and cost of seed and other inputs are conducted and results presented.     

马氏珠母贝CyPB基因的克隆与表达分析

为了探究亲环蛋白B(CyPB)在马氏珠母贝中的作用机制,运用cDNA末端快速扩增(RACE)技术克隆得到马氏珠母贝CyPB基因(PmCyPB)cDNA的全长序列,并且应用实时荧光定量PCR技术对PmCyPB基因在马氏珠母贝不同组织中的表达进行检测。结果显示,PmCyPB基因序列全长1266 bp,其中开放阅读框(ORF)为678 bp,编码225个氨基酸,5′-UTR为62 bp,3′-UTR为526 bp。预测其相对分子量为24829.3,理论等电点5.77。多序列比对结果显示PmCyPB基因与其他物种的CyPB具有较高的保守性。SMART软件对PmCyPB进行蛋白质序列分析,发现它包含亲环蛋白家族典型的肽脯氨酰顺反异构酶的结构域。实时荧光定量PCR数据分析表明,该PmCyPB基因在马氏珠母贝闭壳肌、肝胰腺、血细胞、外套膜、足、性腺、鳃这7种组织中均有表达,在外套膜表达量最高,其次是鳃。结果可为进一步阐述PmCyPB在马氏珠母贝中的免疫防御机制提供一定的理论基础。