马氏珠母贝珍珠囊发育的组织和组织化学研究

按照常规技术进行马氏珠母贝插核育珠,在手术后第1、3、7、15、20、30和60天解剖剪取珍珠囊,利用H E染色等组织化学方法研究马氏珠母贝珍珠囊形成过程中的组织学和组织化学变化。结果表明:珍珠囊表皮细胞来自于移植细胞小片的表皮细胞;在水温27℃条件下,插核后1~3 d来自育珠贝的游走细胞逐渐将细胞小片包围;插核后7~15 d,珠核表面密集来自育珠贝的游走细胞;插核后15～20 d,细胞小片外表皮细胞增殖形成珍珠囊,珍珠囊表皮细胞和细胞核均呈扁平状;插核后20～30 d,扁平状珍珠囊表皮细胞逐渐转变为高柱型,并分泌形成透明的壳皮层物质;在插核后第60天,已形成具有分泌珍珠质功能的扁平状珍珠囊表皮细胞,细胞核呈椭圆形或近圆形。     

马氏珠母贝选系F_2早期选择反应和现实遗传力估计

对马氏珠母贝基础群体进行持续选择建立选系F2,比较了选系F2与对照群体早期生长差别,并估计了选择反应和现实遗传力。结果表明,在第8、14、21和35天,选系F2的平均壳长显著大于对照群体(P<0.05)。在第8、14、21和35天,选择反应和现实遗传力变化范围分别为0.63～0.89和0.36～0.51。本研究表明利用群体选择可以明显改良马氏珠母贝养殖群体的生长性状。     

Construction of cDNA subtractive library from pearl oyster (Pinctada fucata Gould) with red color shell by SSH

The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for differentially expressed genes in red- and non-red-shelled pearl oysters. We constructed forward and reverse cDNA subtractive libraries consisting of 2 506 and 797 clones, respectively. Among 343 randomly selected clones in the forward library, 304 sequences were identified in GenBank using BLASTx and BLASTn. Of the 304 sequences, 13 showed no similarity to known sequences and 291 were matched with known genes of the pearl oyster, including shematrin-1, shematrin-2, shematrin-6, shematrin-7, nacrein, nacrein-like protein, aspein for shell matrix protein, glycine-rich protein, mantle gene 5, 28S, EST00031, EST00036, 16S, and COΙ. In the reverse library, 7 clones were sequenced and analyzed by BLAST. Two sequences shared similarity with EST00036 from the P. fucata subtraction cDNA library, four with the P. fucata mitochondrial gene for 16S rRNA and 1 with P. fucata shematrin-2. We evaluated the expression of 12 genes from the forward library using RT PCR. Two sequences matched with 16S and COΙ so were considered to be false positives. The remaining 10 sequences were differentially expression in the red-shelled pearl oysters. Our results suggest that differential expression of these genes may be related to color variation in the red-shelled family line of the pearl oyster.     

室外大池马氏珠母贝育苗试验

本试验利用一个室外露天水容量为187立方米的水泥池进行马氏珠母贝人工育苗,一次育出贝苗5065万只,平均每立方米水体收贝苗27.08万只。室外大池育苗具有耗饵量少,节约人力,培育的幼虫和贝苗生长快和产苗量大等优点,能够迅速提高贝苗总产量,解决目前存在的贝苗(?)足的困难,值得提倡推广。     

企鹅珍珠贝人工养殖及育珠的研究

在幼贝中间养成中采用柱形笼养殖法,母贝的养成中采用穿耳开放式养殖法,与全程采用锥形笼的传统式养殖方法相比较,进行企鹅珍珠贝人工养殖。结果表明:采用本技术养殖企鹅珍珠贝,在幼贝中间养成阶段,比传统养殖的壳高生长速率提高32·1%(P<0·05),壳长生长速率提高30·3%(P<0·01),成活率提高36%(P<0·01);母贝养成阶段,比传统养殖的壳高生长速率提高28·1%(P<0·05),壳长生长速率提高26·7%(P<0·01),成活率提高18·3%(P<0·01)。同时进行企鹅珍珠贝人工培育游离珠实验,植核贝在休养期和育珠期存活率分别为71·2%和54·3%,留核率分别为29·6·6%和21·0%,成珠率58·6%,优质珠比例为26·7%。     

引进印尼种大珠母贝繁育F1母贝植核育珠研究

以印度尼西亚引进大珠母贝亲本繁育的子代F1群体进行植核育珠,育珠贝数量8086只,在海区休养20d后,统计育珠母贝的成活率与留核率,比较3月与4月植核手术育珠贝的育珠性状差异。结果表明：休养期结束后,育珠贝的成活率与留核率分别为97.57％和90.69％;育珠期3个月时（6月17日）育珠贝的成活率为81.22％;4月植核育珠母贝的留核率与成活率明显高于在3月的植核育珠母贝,但两者之间差异不具统计学意义（P〉0.05）。     

马氏珠母贝的术前处理试验

本试验根据马氏珠母贝手术贝的不同生理状态，分别用控制海水流量、饵料等抑制贝的生殖腺发育，或促进生殖腺发育并诱导产卵排精的方法，对手术贝进行术前处理，结果表明：手术后休养期成活率平均为９２．９％，最高的达９５．３％；育珠期成活率平均为７５．３％。最高的一组达８５．３％；平均每个贝留核数１．０６粒，最高的达１．１７粒，同时珍珠质量明显提高。用术前处理方法，产量和产值可提高５２．３％。     

大珠母贝主要污损及寄居生物的研究

研究雷州半岛自然生活条件、养殖条件下的野生贝和全人工养殖条件下的养殖贝主要污损及寄居生物。结果表明:大珠母贝主要污损及寄居生物共46种,其中自然生活条件下野生贝的污损及寄居生物有24种,养殖条件下野生贝的污损与寄居生物42种,养殖贝的污损及寄居生物有31种;根据附着或寄居部位可将大珠母贝污损及寄居生物可分为4种类型:贝壳表面附生型、贝壳层寄居型、贝壳内侧寄居型、外套腔寄居型;海绵、缨鳃虫、龙介沙蚕、长鳃树蛰虫为贝壳表面附生型主要种类,砗磲江珧虾为外套腔寄居型种类,对大珠母贝危害较小;石蛏、开腹蛤、厥目革囊星虫、有盾海扇虫、才女虫、钻穿裂虫为贝壳层寄居型的主要种类;吻蛇稚虫为贝壳内侧寄居型,对大珠母贝危害较大。自然生活条件下野生贝主要危害种类为石蛏、开腹蛤、厥目革囊星虫、才女虫、钻穿裂虫,养殖条件下野生贝主要危害种类有石蛏、开腹蛤、厥目革囊星虫、有盾海扇虫、吻蛇稚虫、才女虫、钻穿裂虫;养殖贝受寄居生物危害较小。     

合浦珠母贝两个种群染色体组型的分析

以北部湾和大亚湾两个地域的野生合浦珠母贝种群为研究对象，采用成贝的鳃组织，经空气干燥法制片进行染色体组型分析。结果表明两地种群的核型公式都为2N=28=16m+6sm+4st+2t，NF=50，但在染色体排序方面表现出较明显的群体差异。并与以往研究报道相比较，分析了不同的实验结果及可能产生差异的原因。     

马氏珠母贝早春育苗,缩短母贝养成期试验

在室内人工飼养马氏珠母贝亲贝,进行早春育苗。比常规生产育苗提前二个月。生长快,贝体健壮,经养殖18个月长至壳高7.1厘米,体重52克。60％以上达施术贝标准,相当于常规生产贝苗26个月的生长水平。相对地缩短了养殖周期,提高了经济效益。且设备简单,操作方便,利于推广。     

企鹅珍珠贝附壳珍珠的培育

以7种聚乙烯塑料核型为珠核,正常壳形与二壳隆起的畸形企鹅珍珠贝为手术贝,培育附壳珍珠。养殖6个月,结果表明:壳形正常的育珠贝成活率为73.3%～93.8%,成珠率55.0%～82.0%;畸形贝成活率为60%,成珠率53.3%。统计分析表明:珠核高度是影响育珠贝成活率和成珠率的主要因素,珠核越高,育珠贝成活率和成珠率越低。畸形贝与正常壳形贝成活率和成珠率存在极显著差异(P<0.01),畸形贝不宜用作手术贝。     

马氏珠母贝育珠细胞小片和珠核处理技术研究Ⅱ:不同处理液在广东徐闻的育珠效果

通过海区插核育珠试验,对不同处理液匹配组进行进一步优化、筛选,找出适于广东育珠海区的育贝小片处理液及与之匹配的珠核处理液。结果表明:1)匹配适宜的处理液有降低吐核率的作用,8个试验小组中W0、Y3组的吐核率仅31%~32%,明显低于对照组的46.2%(P<0.01),说明匹配液有明显增加组织亲和力、降低吐核率的效果;2)育珠贝的死亡主要发生在育珠前期,与贝的吐核行为有关;3)小片处理液中,C类药物成分对吐核率的高低有影响,0.6%C2不适宜添加到处理液中,而1%C3添加到处理液中有降低吐核率的效果;4)筛选出W0、W1、Y3三组适宜的匹配方案,即W0、W1、Y3三种小片处理液与核处理液C3匹配适宜,其中W0匹配组育珠效果最佳,即成活率为57.8%,百贝收珠数为101.2粒、优珠率为67.5%,比传统处理组(对照组)有明显提高;5)对W0、W1、Y3三组的不同育珠时限(8、10、13个月)的育珠情况进行了比较,当育珠期延长至1年时,Y3组育珠效果良好;6)利用评价指数(即优质珍珠数占手术贝总数的比例)可评判育珠效果,与分析、综合评估结论一致,前者可量化评判数值,使评判更加直观,简易。     

马氏珠母贝黄壳色选系F1和养殖群体形态性状比较

<正>马氏珠母贝(Pinctada martensii)是我国南方养殖的一种重要经济贝类,长期以来一直是我国主要的海水育珠的主要贝类,用马氏珠母贝育珠是广东、广西和海南沿海部分地区经济发展的支柱性产业。近年来,我国海水珍珠的质量出现明显滑坡,严重地削弱了在国际市场上的竞争力。为提高海水珍珠质量和在国际市场上的竞争力,国内科技工作者已经进行了大量的研究工作,这些工作主要包括对马氏珠母贝养殖群体性状的改良、育珠技术的优化和海水珍珠形成机理的研究[1-5]。     

马氏珠母贝黄壳色选育系G_1遗传结构的ISSR分析

挑选11个黄壳色的马氏珠母贝养殖个体为亲本繁殖子代群体,并随机选取50个体为亲本,建立对照群体。采用ISSR分子标记对马氏珠母贝黄壳色群体和对照群体的遗传结构差异进行分析。结果表明,黄壳色和对照群体的遗传多样性分别为0.358 7和0.373 3,多态位点比例分别为86.89%和90.16%;群体间遗传分化系数为3.75%。可见,经过一代选择后,黄壳色群体遗传结构指标略低于对照群体,但两个群体未发生明显分化。     

马氏珠母贝育珠细胞小片和珠核处理技术研究Ⅰ:不同处理液在海南陵水育珠的效果

研究8组不同小片和核处理液在海南陵水海区的育珠效果,优化、筛选适宜该海区育珠的小片处理液及与之匹配的珠核处理液。结果显示:1)处理组手术贝休养期的吐核率与死亡率均显著低于对照组,表明处理液可促进伤口愈合并抗感染;2)处理组育珠8个月后的珠层厚度平均可达0.5 mm以上,与对照组0.3 mm的珠层厚度差异极显著(P<0.01),表明处理液具有明显促进珍珠质分泌的作用;3)优化筛选出核处理液C3,其增强核亲和力的效果明显优于C1(P<0.05);4)W处理组育珠贝死亡率平均小于22%,明显低于对照组(36.7%)和Y处理组(31.45%)(P<0.01),表明W处理液效果优于Y处理液;5)在8个处理组中,筛选出W0、W2、Y3三个匹配组,其育珠效果明显优于对照组(P<0.01)。引入综合评价指数即优良珍珠数占育珠贝总数的比例,以量化育珠效果便于比较     

High Pressure Treatment Changes Spoilage Characteristics and Shelf Life of Pacific Oysters(Crassostrea gigas) During Refrigerated Storage

The effects of high pressure(HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters(Crassostrea gigas) during refrigerated storage were studied.Results showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle,pressures higher than 350 MPa caused excessive release as the shells of oysters were broken,thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of shells.HP treatment(300 MPa,2 min) was proper for the shucking of Pacific oyster(Crassostrea gigas) in China.This treatment caused no organoleptic disadvantage.Moreover,HP treatment resulted in obvious differences in biochemical spoilage indicators(p H,TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during storage.HP treatment(300 MPa,2 min) also led to a reduction of aerobic bacterial count(APC) by 1.27 log cycles.Furthermore,the APC values of oysters treated by HP were always lower than those of the control samples during storage.Based on the organoleptic,biochemical and microbiological indicators,shelf life of 6-8 d for control and 12 d for HP-treated oysters could be expected.HP treatment showed great potential in oyster processing and preservation.     

珍珠的扫描电镜观察

作者应用扫描电子显微镜,对褶纹冠蚌(Cristaria plicata Leach)不同形成阶段的无核珍珠,对三角帆蚌(Hyriopsis cumingii Lea)、大珠母贝(Pinctada maxima Jameson)和马氏珠母贝(P.martensii Dunker)的有核珍珠进行表面和断面的比较观察,以探讨珍珠的形成过程及其细微空间结构。实验表明,珍珠的最内层是不定形的基质,往往还有一些结晶颗粒;在很多珍珠中,紧邻基质层的是或薄或厚的方解石晶层;珍珠的外围是较厚的霰石晶层。组成霰石晶层的单元晶为长3-5微米、宽2-3微米和厚0.2-0.5微米的不规则多边形板块。板块的大小由珍珠囊上皮细胞的表面积决定。随着育珠蚌(贝)的种类不同,霰石单元晶在珍珠表面的融合状况也有所差异,进而造成珍珠质地的差异。实验还观察到了珍珠的一种新的结晶形式。     

工厂化培育海水珍珠的研究

在海区中养殖珍珠常受到台风、淡水、低温等自然灾害的影响和敌害生物的侵袭,使育珠贝大量死亡。在岸上水槽系统,在人为控制的条件下养殖海水珍珠——工厂化育珠,则可避免上述的影响。本文介绍工厂化培育海水珍珠的试验设施、育珠试验、试验结果与评价。     

Genome-wide survey and analysis of microsatellites in the Pacific oyster genome: abundance,distribution, and potential for marker development

Microsatellites are a ubiquitous component of the eukaryote genome and constitute one of the most popular sources of molecular markers for genetic studies. However, no data are currently available regarding microsatellites across the entire genome in oysters, despite their importance to the aquaculture industry. We present the fi rst genome-wide investigation of microsatellites in the Pacifi c oyster Crassostrea gigas by analysis of the complete genome, resequencing, and expression data. The Pacifi c oyster genome is rich in microsatellites. A total of 604 653 repeats were identifi ed, in average of one locus per 815 base pairs(bp). A total of 12 836 genes had coding repeats, and 7 332 were expressed normally, including genes with a wide range of molecular functions. Compared with 20 different species of animals, microsatellites in the oyster genome typically exhibited 1) an intermediate overall frequency; 2) relatively uniform contents of(A)n and(C)n repeats and abundant long(C)n repeats(≥24 bp); 3) large average length of(AG)n repeats; and 4) scarcity of trinucleotide repeats. The microsatellite-fl anking regions exhibited a high degree of polymorphism with a heterozygosity rate of around 2.0%, but there was no correlation between heterozygosity and microsatellite abundance. A total of 19 462 polymorphic microsatellites were discovered, and dinucleotide repeats were the most active, with over 26% of loci found to harbor allelic variations. In all, 7 451 loci with high potential for marker development were identifi ed. Better knowledge of the microsatellites in the oyster genome will provide information for the future design of a wide range of molecular markers and contribute to further advancements in the fi eld of oyster genetics, particularly for molecular-based selection and breeding.     

利用原子吸收光谱测定珍珠加工前后元素含量的变化

利用空气—乙炔火焰原子吸收光谱法对马氏珍珠进行了１３个元素的测定，结果表明优质珍珠与劣质珍珠主要在Ｚｎ、Ｍｇ、Ｃｕ、Ｍｎ、Ｐｈ、Ｋ、Ｃｒ、Ｓｒ等元素含量方面有差异。珍珠在加工前后变化很大的元素是Ｚｎ、Ｍｇ、Ｃｕ、Ｎａ、Ｍｎ、Ｃｒ、Ｓｒ等。根据一些元素对珍珠质量的显著影响，提出在加工过程应注意对珍珠质量有利元素的加入和有损珍珠质量的元素的去除。