海湾扇贝衣原体样生物超微结构观察

对海湾扇贝生长不同阶段的样品进行了透射电镜观察,在样品消化腺上皮细胞内发现类衣原体感染。该类衣原体具有原体、网状体和中间体等典型发育阶段,原体个体小而致密,网状体大而疏松,以等体积分裂进行繁殖。在细胞质内形成单层膜包被的包涵体,包涵体发育晚期破裂,宿主细胞崩解,衣原体逸出。衣原体感染可导致细胞核变形,染色质凝聚,内质网核糖体脱落,线粒体内嵴消失。     

用流式细胞仪测定扇贝血细胞吞噬活性

采用流式细胞仪技术对栉孔扇贝(Chlamysfarreri)和海湾扇贝(Argopectenirradians)血细胞吞噬活性进行了测定。通过对缓冲体系的筛选和比较,建立了扇贝血细胞吞噬活性的流式细胞仪检测方法,并应用该技术对两种扇贝血细胞的吞噬活性进行了比较研究。结果发现在TBS(0.05mol.L-1Tris-HCl,pH7.4;2%glucose;2%NaCl;20mmol.L-1EDTA)和PBS体系中,扇贝血细胞的吞噬活性几乎完全受到抑制,在CMPBS(0.1mol.L-1PBS,pH7.4;2%NaCl;2%glucose;1.0mmol.L-1CaCl2;0.5mmol.L-1MgCl2)体系中细胞吞噬活性略有升高,而在海水缓冲液中细胞吞噬活性最高,其中海湾扇贝和栉孔扇贝血细胞的吞噬率分别达到了26.73%和19.89%,且海湾扇贝血细胞的吞噬率显著高于栉孔扇贝(P<0.05)。研究结果为进一步探讨扇贝血细胞吞噬功能提供了方法依据。     

墨西哥湾扇贝精子的超微结构

报道了墨西哥湾扇贝成熟精子在SEM和TEM下的超微结构观察结果。墨西哥湾扇贝的精子为典型的原生型,精子全长约43～45μm,头部长约2．1～2．4μm。精子主要由头部、中段和尾部三部分组成。头部顶体明显突出,呈倒V形;顶体下方为细胞核,细胞核近似卵圆形。在细胞核内部或边缘,能观察到有一个或几个形状较为规则的核泡。中段的主要结构有线粒体和中心体,中段的横切面有4个线粒体围绕在中心体的周围。尾部细长,尾部鞭毛横切面为典型的“9 2”结构。     

扬子鳄外周血细胞的超微结构

对扬子鳄血细胞亚显微结构进行透射电镜观察。结果表明：在外周血细胞中可区分出红细胞、嗜中性粒细胞、嗜酸性粒细胞、嗜碱性粒细胞、单核细胞、淋巴细胞以及血栓细胞。电镜图像显示：与其它爬行动物相比,各类血细胞体积较小并具有不同程度的变形运动及吞噬能力。红细胞的特征是长梭形,其长短径之比值超过3.0。在外周血液中发现了多种未成熟型血细胞;进入外周血液中的红细胞普遍已分化到一定程度,但有的仍须在外周血液中完成其最后的发育;单核细胞在外周血液中经历了从幼单核细胞到成熟单核细胞的过程,并描述了从未成熟到成熟阶段细胞的超微结构的变化;嗜中性粒细胞在外周血液中经历了从早幼粒细胞、中幼粒细胞,晚幼粒细胞到成熟粒细胞的过程,描述了嗜中性粒细胞各个发育阶段细胞的超微结构及特征,并讨论了嗜天青粒细胞和嗜中性粒细胞的关系。     

四种对虾血细胞组成及超微结构

本文应用电镜超薄切片技术,对中国对虾,日本对虾,长毛对虾和草虾的血细胞进行超微结构的研究,根据血细胞形态,超微结构特点,特别是胞质中特征性颗粒的大小和内部结构,区分为四类：１．透明细胞,其胞质不含特征性颗粒,具有较强的吞噬能力;２．小颗粒细胞,其胞质含有高电子密度的小圆形颗粒和条纹状大颗粒,在对虾防御反应中起着关键性作用;３．大颗粒细胞,其胞质中含有高电子密度的均质大颗粒,在宿主防御反应中起着细胞     

成年草鱼外周血细胞的超微结构

用透视电镜技术研究了成年草鱼外周血细胞的超微结构，结果表明：在外周血细胞中可区分出红细胞，淋巴细胞，单核细胞，嗜中性白细胞，嗜酸性白细胞和血检细胞；嗜碱性白细胞无论在血涂片上或超薄切片上都没有发现。电镜图像显示，在红细胞中，仅能看到少数线粒体和液泡。淋巴细胞以短的伪足，较多的游离核糖体和滑面内质网为其特征。单核细胞的特征是具有较多的伪足和胞质液泡以及偏位核。在外周血液中发现了嗜中性白细胞生长、发育、功能成熟和衰退的全过程，描述了嗜中性白细胞的幼稚型、成熟型和衰退型细胞的超微结构。在成年草鱼外周血中，还发现了一种新型的颗粒细胞，它的特殊颗粒为大的六角形或棒状致密结晶颗粒，对上述特殊颗粒细胞的属性也进行了讨论。     

虾夷扇贝精子的超微结构

用扫描和透射电镜研究了虾夷扇贝(Patinopecten yessoensis)精子的超微结构.虾夷扇贝精子为典型的原生型,全长50μm左右,头部长约3 μm.精子主要由头部、中段和尾部三部分组成.头部顶体突出,呈倒"V"形;顶体下方为精核,电子密度较高且占头部大部分,具有核前窝(anterior nuclear fossa)、核后窝(posterior nuclear fossa)和植入窝(implantation fossa);4～5个近圆形的线粒体围绕着中心粒复合体形成精子的中段.尾部细长,尾部鞭毛横切面为典型的"9 2"结构.     

史氏鲟外周血细胞的显微及超微结构

采用血细胞计数、光学显微及电子显微技术对二龄史氏鲟外周血细胞的数目、形态及结构进行了研究。二龄史氏鲟红细胞的数目为47.75×104个/mm3,白细胞数目为2.9万个/mm3,其中淋巴细胞所占比率最高。史氏鲟的外周血中除正常红细胞外,还有处于分裂状态及未成熟的红细胞。史氏鲟外周血中的白细胞有四种类型,分别为淋巴细胞、粒细胞、血栓细胞和单核细胞。其中粒细胞有两种,即嗜中性粒细胞和嗜酸性粒细胞。嗜中性粒细胞含有多种形状的核,其中分叶的核数目较多,粒细胞及淋巴细胞均类似于哺乳动物。对史氏鲟外周血细胞细微结构的观察显示:红细胞中具有少量的细胞器;淋巴细胞结构典型;单核细胞较粒细胞稍小且具有较多线粒体;血栓细胞具有梭形和圆形两种,胞质较少,其中梭形的血栓细胞胞质几乎透明;对粒细胞的颗粒按照形状和电子密度进行了分类。     

紫扇贝与海湾扇贝通用SSR的检测及其在杂交子代鉴定中的应用

以紫扇贝DNA为模板,用已开发的147个海湾扇贝微卫星标记引物扩增,结果表明100个微卫星标记能成功扩增,其中有47个表现出多态性,等位基因数目从2到9不等.观测杂合度范围为0.128 0～1.000 0(平均0.660 4),期望杂合度范围为0.503 1～0.862 1(平均0.671 9),有6个位点偏离Hardy-Weinberg平衡(P<0.05).用7对引物分别对紫扇贝、海湾扇贝及其种间正反杂交F1各30个个体进行PCR扩增,发现它们可明确区分紫扇贝与海湾扇贝,且所检测60个杂交子代均同时含海湾扇贝与紫扇贝的相应种特异性条带,证明全部为种间杂交子代.将该7对引物的扩增产物克隆测序,发现这些位点在两种扇贝中的序列同源率为40.22%～91.95%,其中3个位点在紫扇贝中的扩增产物仍然含有微卫星.     

人工雌核发育草鱼外周血细胞的显微及超微结构观察

本文利用光学显微镜、透射电子显微镜、扫描电子显微镜首次对人工雌核发育草鱼的外周血细胞进行了观察。观察结果表明,雌核发育草鱼外周血液中可区分出七种不同类型的血细胞：红细胞、血栓细胞、淋巴细胞、单核细胞、嗜中性粒细胞、嗜酸性粒细胞和嗜碱性粒细胞,这些血细胞的显微及超微结构与已报道过的鲤鱼、鲫鱼、普通草鱼相应血细胞的结构基本相同。     

Three ferritin subunits involved in immune defense from bay scallop Argopecten irradians

Ferritin is a ubiquitous protein that plays an important role in iron storage and iron-withholding strategy of innate immunity. In this study, three genes encoding different ferritin subunits were cloned from bay scallop Argopecten irradians (AiFer1, AiFer2 and AiFer3) by rapid amplification of cDNA ends (RACE) approaches based on the known ESTs. The open reading frames of the three ferritins are of 516 bp, 522 bp and 519 bp, encoding 171,173 and 172 amino acids, respectively. All the AiFers contain a putative Iron Regulatory Element (IRE) in their 5′-untranslated regions. The deduced amino acid sequences of AiFers possess both the ferroxidase center of mammalian H ferritin and the iron nucleation site of mammalian L ferritin. Gene structure study revealed two distinct structured genes encoding a ferritin subunit (AiFer3). Quantitative real-time PCR analysis indicated the significant up-regulation of AiFers in hemocytes after challenged with Listonella anguillarum, though the magnitudes of AiFer1 and AiFer2 were much higher than that of AiFer3. Taken together, these results suggest that AiFers are likely to play roles in both iron storage and innate immune defense against microbial infections.     

化学物质对墨西哥湾扇贝幼虫变态的诱导

用KCl、肾上腺素、去甲肾上腺索和氯化胆碱进行了墨西哥湾扇贝(Argopecten irradians concentricus)幼虫变态的诱导作用实验。结果表明,KCl、肾上腺素、去甲肾上腺素和氯化胆碱对墨西哥湾扇贝幼虫变态均有显著诱导作用。KCl在处理时间为12～48h范围内均有诱导作用,13．42mmol／L和20．13mmol／L,的KCl诱导效果较好,变态率均提高10％以上。1．0～50gmol／L的肾上腺素在处理时间为1～12h较适宜,此时变态率均提高10％以上。1．0～50μmol／L,的去甲肾上腺素在处理时间为1～24h都较适宜,变态率均提高10％以上,最高可提高31．07％。10～100μmol／L氯化胆碱的适宜诱导时间为12～48h,变态提高率均超过10％,在10．37％～16．40％之间。1000μmol／L的氯化胆碱在处理时间为12h时诱导效果较明显,变态率可以提高19．14％,超过12h,变态率明显下降。10000μmol／L的氯化胆碱明显产生毒害作用,幼虫变态率均为零,而幼虫的死亡率均为100％。     

盐度对墨西哥湾扇贝幼虫和稚贝生长与存活的影响

2000年4月和2001年4月在浙江省玉环县抛西水产育苗场研究了海水盐度对墨西哥湾扇贝浮游幼虫和稚贝生长和存活的影响。结果表明：浮游幼虫的适宜盐度为16．54—36．58,最适生长盐度为23．38—30．02;稚贝的适宜盐度为23．38—42．70,最适生长盐度为23．38—36．58。     

Warming and hypoxia reduce the performance and survival of northern bay scallops (Argopecten irradians irradians) amid a fishery collapse

Warming temperatures and diminishing dissolved oxygen (DO) concentrations are among the most pervasive drivers of global coastal change. While regions of the Northwest Atlantic Ocean are experiencing greater than average warming, the combined effects of thermal and hypoxic stress on marine life in this region are poorly understood. Populations of the northern bay scallop, Argopecten irradians irradians across the northeast United States have experienced severe declines in recent decades. This study used a combination of high-resolution (~1 km) satellite-based temperature records, long-term temperature and DO records, field and laboratory experiments, and high-frequency measures of scallop cardiac activity in an ecosystem setting to quantify decadal summer warming and assess the vulnerability of northern bay scallops to thermal and hypoxic stress across their geographic distribution. From 2003 to 2020, significant summer warming (up to ~0.2°C year⁻¹) occurred across most of the bay scallop range. At a New York field site in 2020, all individuals perished during an 8-day estuarine heatwave that coincided with severe diel-cycling hypoxia. Yet at a Massachusetts site with comparable DO levels but lower daily mean temperatures, mortality was not observed. A 96-h laboratory experiment recreating observed daily temperatures of 25 or 29°C, and normoxia or hypoxia (22.2% air saturation), revealed a 120-fold increased likelihood of mortality in the 29°C-hypoxic treatment compared with control conditions, with scallop clearance rates also reduced by 97%. Cardiac activity measurements during a field deployment indicated that low DO and elevated daily temperatures modulate oxygen consumption rates and likely impact aerobic scope. Collectively, these findings suggest that concomitant thermal and hypoxic stress can have detrimental effects on scallop physiology and survival and potentially disrupt entire fisheries. Recovery of hypoxic systems may benefit vulnerable fisheries under continued warming.     

Cytogenetic characterization of the bay scallop, Argopecten irradians irradians, by multiple staining techniques and fluorescence in situ hybridization

The chromosomes of Argopecten irradians irradians were studied by various cytogenetic approaches. Conventional chromosome characterization built on C-banding, DAPI-staining, and silver staining was complemented by the physical mapping of ribosomal DNA and telomeric sequence (TTAGGG)n by FISH. Results showed that the constitutive heterochromatin revealed by C-banding was mainly distributed at telomeric and centromeric regions. However, interstitial C-bands were also observed. The pattern of DAPI banding was almost consistent with that of C-banding. Silver staining revealed that NORs were located on the short arms of chromosome 3 and 10, and this was further confirmed by FISH using 18S-28S rDNA. 5S rDNA was mapped as two distinguishable loci on the long arm of chromosome 11. 18S-28S and 5S rDNA were located on different chromosomes by sequential FISH. FISH also showed that the vertebrate telomeric sequence (TTAGGG)n was located on both ends of each chromosome and no interstitial signals were detected. Sequential 18S-28S rDNA and (TTAGGG)n FISH demonstrated that repeated units of the two multicopy families were closely associated on the same chromosome pair.     

Development of Expressed Sequence Tags from the Bay Scallop, Argopecten irradians irradians

The bay scallop, Argopecten irradians irradians, introduced from North America, has become one of the most important aquaculture species in China. Inan effort to identify scallop genes involved in host defense, a high-quality cDNA library was constructed from whole body tissues of the bay scallop. A total of 5828 successful sequencing reactions yielded 4995 expressed sequence tags (ESTs) longer than 100 bp. Cluster and assembly analyses of the ESTs identified 637 contigs (consisting of 2853 sequences) and 2142 singletons, totaling 2779 unique sequences. Basic Local Alignment Search Tool (BLAST) analysis showed that the majority (73%) of the unique sequences had no significant homology (E-value ≤ 0.005) to sequences in GenBank. Among the 748 sequences with significant GenBank matches, 160 (21.4%) were for genes related to metabolism, 131 (17.5%) for cell/organism defense, 124 (16.6%) for gene/protein expression, 83 (11.1%) for cell structure/motility, 70 (9.4%) for cell signaling/communication, 17 (2.3%) for cell division, and 163 (21.8%) matched to genes of unknown functions. The list of host-defense genes included many genes with known and important roles in innate defense such as lectins, defensins, proteases, protease inhibitors, heat shock proteins, antioxidants, and Toll-like receptors. The study provides a significant number of ESTs for gene discovery and candidate genes for studying host defense in scallops and other molluscs.     

Different responses to selection in two stocks of the bay scallop, Argopecten irradians irradians Lamarck (1819)

Two different stocks (A and B) of the bay scallop Argopecten irradians irradians (Lamarck, 1819) were used to test mass selection on growth. Stock A was a descending stock from the initial introduction from U.S.A. in 1982, which had been cultured in China for about 20 years. Stock B was the third generation from a recent introduction from U.S.A. in 1999. Truncation selection was conducted by selecting the largest 11% scallops in shell length from Stock A and the largest 12.7% scallops from Stock B as parents for the respective selected groups. Before the removal of parents for truncation selection, equal numbers of scallops were randomly chosen from Stock A and B to serve as parents for the control groups. Offspring from the four groups were reared under the same hatchery, nursery, and grow-out conditions. Values of response to selection and realized heritability at larvae, spat and grow-out stages for Stock B were all significantly (P<0.001) higher than its counterpart for Stock A. For Stock A, no significant response to selection was observed (P>0.05) at any stage, and the realized heritability for shell length was 0.015±0.024 for larvae, 0.040±0.027 for spat, and 0.080±0.009 for grow-out, respectively. For Stock B, however, significant (P<0.05) response to selection was observed, and the realized heritability for shell length was 0.511±0.010 for larvae, 0.341±0.022 for spat, and 0.338±0.015 for grow-out. On average, responses to selection at the three stages for Stock B was 30×, 7.1×, and 3× higher than its counterpart for Stock A, respectively. Accordingly, realized heritability at above stages for Stock B was 33×, 7.5×, and 3.2× higher than its counterpart for Stock A, respectively. Differences in response to selection and realized heritability between the two stocks are presumably due to differences in genetic variability. As the 20th generation from the initial introduction consisted of only 26 scallops, Stock A is known to be highly inbred, while inbreeding in Stock B is negligible.     

不同大小规格墨西哥湾扇贝(Argopecten irradians concentricus)转录组分析及生长相关基因筛选

墨西哥湾扇贝(Argopecten irradians concentricus)是中国双壳贝类养殖的重要经济品种,具有较高的研究价值,然而,转录组学及基因组学信息的匮乏,严重制约了该贝的遗传改良进程。本研究基于Illumina Hi SeqTM2000平台,对5月龄大规格(平均体质量16.05 g)和小规格(平均体质量5.57 g)墨西哥湾扇贝进行转录组测序,经de nove组装,大、小规格墨西哥湾扇贝分别获得120 563和118 794条高质量unigenes,unigene的平均长度分别为944 bp和969 bp;按照FDR≤0.001且|log2Ratio|≥1的原则,共筛选出9 901个差异表达基因,其中,大规格组相对于小规格组,上调基因4 976个(50.26%),下调基因4 925个(49.74%);六大公共数据库Blast比对结果显示,差异表达基因在Nr数据库的注释率最高,其次是GO数据库;从已获功能注释的差异表达基因中筛选得到47个生长相关候选基因,涉及多个生长因子及其受体;GO功能富集结果显示,膜、L-氨基酸运输和糖基键水解酶活性分别是细胞组分、生物过程和分子功能富集unigene最多的条目;Pathway富集分析发现,3 699条差异表达基因被成功注释到252条代谢通路中,其中33条为显著性富集通路(p<0.05),富集度最高的是焦点粘附;大规格组中共鉴定出10 870个SSRs和242 551个SNPs,小规格组中共鉴定出10 857个SSRs和228 121个SNPs。研究结果为墨西哥湾扇贝分子标记批量开发、功能相关基因挖掘以及分子遗传育种提供了理论数据支撑。