不同pH对海湾扇贝胚胎发育及幼虫生长发育的影响

为探究pH对海湾扇贝(Argopecten irradia)胚胎发育及幼虫生长发育的影响，本研究以pH 8.0~8.2为对照组，分析不同pH (分别为7.6~7.7、7.3~7.4、7.0~7.1和6.7~6.8)对海湾扇贝胚胎及幼虫的影响。结果显示，随着pH的降低，各实验组孵化率降低，畸形率增高，孵化时间延长，且幼虫个体明显小于对照组(P<0.05)。D形幼虫期与壳顶幼虫期幼虫存活率与生长速率均显著低于对照组(P<0.05)。幼虫发育至第8天时，pH 7.0~7.1与pH 6.7~6.8实验组的存活率分别为6.1%和5.6%，而对照组为75.2%，除pH 7.6~7.7组外，各实验组生长速率均在3.4 μm/d及以下，基本呈现生长停滞状态。眼点幼虫附着率与对照组差异显著(P<0.05)，第7天时，pH 6.7~6.8实验组附着率仅为31.7%。研究表明，海水pH变化对海湾扇贝早期胚胎及幼虫生长发育具有显著影响，该研究为评估pH变化对海湾扇贝等经济贝类资源和养殖产业的影响提供了参考资料。     

3种滤食性贝类对塔玛亚历山大藻的摄食研究

20 0 3年 4月在实验室内采用静水法 ,研究了长牡蛎、紫贻贝、栉孔扇贝对塔玛亚历山大藻的清滤率 (CR)和摄食率 (IR) ,实验时间持续 3d ,水温 17℃。实验中每 1种贝都分别投喂 :(1)叉鞭金藻 (对照藻 ) ,(2 )叉鞭金藻 +塔玛亚历山大藻去藻过滤液 1.5L ,(3)叉鞭金藻 +塔玛亚历山大藻细胞。结果表明 ,塔玛亚历山大藻过滤液 ,对 3种贝的清滤率的无明显影响 (P >0 .0 5 ) ;3种贝对塔玛亚历山大藻和叉鞭金藻混合液的清滤率与对照组相比明显降低 (P <0 .0 1) ;而对塔玛亚历山大藻的摄食率和保留率 3d间无显著变化 ;实验期间 ,随时间的变化 ,牡蛎对混合液的清滤率变化最大 ,贻贝次之 ,扇贝则无明显著变化 (P >0 .0 5 ) ;如果以摄食率作为指标 ,贻贝在控制赤潮方面的潜力较大 ,值得今后进一步研究。     

海湾扇贝“中科红”品种与普通养殖群体不同温度下早期性状的比较

采用自交、杂交和混交等不同的交配方式分别获得海湾扇贝“中科红”品种和普通养殖群体（对照组）的受精卵和幼虫，在20 ℃、23 ℃和26 ℃三个温度条件下培养，比较了两个群体在不同温度下的孵化率、10日龄幼虫存活率、1日龄和10日龄幼虫壳长。实验结果表明：“中科红”海湾扇贝自交系、杂交系和混交系的孵化率均大于对照组。自交系10日龄幼虫存活率显著高于对照组（P＜0.05），而杂交系和混交系的10日龄幼虫存活率小于对照组，但差异不显著（P＞0.05）。“中科红”海湾扇贝自交系（P＜0.05）和混交系幼虫的1日龄壳长大于对照组，杂交系的显著小于对照组（P＜0.05）。幼虫生长10日后，“中科红”海湾扇贝自交系、杂交系（P＜0.05）和混交系幼虫壳长均比对照组大，表现了较强的生长优势。温度对4个性状均有显著影响（P＜0.05）。“中科红”海湾扇贝对低温（20 ℃）和高温（26 ℃）的耐受性均高于对照组。     

4种海洋微藻酸性磷酸酶的分离纯化及其性质的研究

提取、纯化了4种海洋徽藻的酸性磷酸酶,确定了酸性磷酸酶的条件并研究其性质.结果显示,在37℃条件下,塔玛亚历山大藻酸性磷酸酶回收得率低,但酶活最高;确定各徽藻酶促反应初速度均恒定的时间为15 min;三角褐指藻、塔胞藻、塔玛亚历山大藻、海链藻的酸性磷酸酶分别在酶浓度为0.96、0.29、0.25、14.9 mg/mL酶促反应速度达最高；三角褐指藻、塔胞藻、海链藻的酸性磷酸酶最适pH值为3,而塔玛亚历山大藻为4;37℃下各藻产生的酸性磷酸酶米氏常数为:塔玛亚历山大藻＜塔胞藻＜三角褐指藻＜海链藻.试验证实,塔玛亚历山大藻在磷源限制条件下,较其他3种海洋徽藻更易于利用有机溶解磷;塔玛亚历山大藻在利用海洋微藻生产酸性磷酸酶方面极具应用前景.     

水温对石磺胚胎发育的影响

通过实验室研究，对石磺（Onchidium sp．）胚胎发育过程进行了详细观察，比较了不同水温下石磺胚胎发育的速度，探讨了膜内面盘幼虫孵化出膜的主要条件。结果表明：石磺的胚胎发育过程类似于肺螺亚纲其他贝类，行体内受精，刚产出的卵为受精卵，细胞未进行分裂，卵裂从卵产出体外开始，分别经过卵裂期，囊胚期，原肠期，膜内担轮幼虫期，膜内面盘幼虫期，经过孵化期孵化出膜为自由生活的面盘幼虫期。对各阶段幼体的大小、形状、内部器官等特征以及发育变态过程进行了详细的显微观察和描述。26℃，28℃，30℃3个水温组中，从受精卵到膜内面盘幼虫孵化出膜分别需要300h，290h，288h；发现影响幼虫孵化出膜的主要因素是水温和海水的刺激作用；繁殖盛期卵群工厂化水泥池自然水温孵化时间为10～14d。并报道了水温低于23℃时石磺胚胎停止发育现象。     

扇贝异源三倍体诱导

荧光显微观察表明,20℃水温下,栉孔扇贝(Chlamysfarreri)的卵与海湾扇贝(Argopecten irradians)的精子可以正常受精和发育,具备人工诱导三倍体的可行性.亲贝充分促熟后,分开催产,以20:1的精卵比授精;在50%的受精卵排出第1极体时,以60mg/L 6-二甲基氨基嘌呤(6-DMAP)处理受精卵10～25 min,可诱导75.23%～92.14%的三倍体;6-DMAP处理15 min综合诱导效果最好,三倍体诱导率可达88.56%,孵化率可达53.52%.得到的三倍体幼虫经基因组原位杂交(Genomicin situ hybridization,GISH)验证,为含有2套栉孔扇贝染色体组和1套海湾扇贝染色体组的异源三倍体.孵化后诱导组与杂交对照组(未经6-DMAP处理)幼虫生长越来越缓慢,受精后14 d其幼虫存活率分别下降到0.000 67%和0.002 24%,没有幼虫度过附着变态期.GISH分析显示,栉孔扇贝与海湾扇贝不同倍性的杂种后代早在担轮幼虫阶段就出现母本偏向性染色体转变.     

低盐诱导海湾扇贝三倍体育苗技术的研究

通过低盐海水浸泡海湾扇贝受精卵抑制受精卵第二极体释放的方法诱导海湾扇贝产生三倍体。当海湾扇贝的受精卵40%出现第一极体时,立即用不同盐度梯度即22.5、20、17.5、15、12.5、10、7.5、对照组(盐度30)的海水对受精卵进行处理10、15min后,马上将处理的受精卵移入正常海水中孵化。实验结果表明,不同梯度低盐海水可以诱导海湾扇贝产生三倍体,盐度为20以上时,三倍体诱导率小于2.91%,但随着盐度的下降,三倍体诱导率迅速提高,当盐度为12.5时,三倍体诱导率高达85.91%。当盐度低于7.5时,由于D形幼虫极少,三倍体诱导率无法测出。在处理时间上,15min的处理效果比10min处理效果好。因此,本研究在低盐度条件下抑制受精卵第二极体产生海湾扇贝三倍体的最佳处理方法是低盐范围在12.5～15之间,处理时间为15min,三倍体诱导率高,孵化率也较高,适合生产上推广应用。     

塔玛亚历山大藻对中国明对虾肝胰腺和鳃SOD、GST和MDA的影响

本文选择在我国分离得到的一株能典型产生麻痹性贝毒(PSP,Paralytic Shellfish Poison)的有毒赤潮甲藻塔玛亚历山大藻(Alexandrium tamarense,ATHK株),研究其是否能通过引发中国明对虾的脂质过氧化作用, 使机体产生过多活性氧自由基, 导致氧化损伤而发挥其毒性作用。塔玛亚历山大藻粗提液经肌肉注射方式染毒中国明对虾,于染毒后1、3、6、12、24和48 h 测定肝胰腺和鳃SOD,GST活力和MDA含量的影响。结果显示,染毒后 1-6 h, 对虾肝胰腺和鳃组织SOD,GST酶活力均增加,12和48h鳃组织的上述指标受到抑制。对虾肝胰腺MDA含量除1h外未见明显改变,鳃中MDA含量随时间增加呈升高趋势。研究表明：塔玛亚历山大藻粗提液在中国明对虾体内代谢过程中能诱导对虾产生活性氧自由基,塔玛亚历山大藻粗提液能诱导MDA含量增加,降低SOD和GST活力,能够引发鳃的脂质过氧化,对鳃造成氧化损伤。     

细胞凝集素探针对典型赤潮生物的定量检测

采用14种异硫氰酸荧光素（FITC）标记的细胞凝集素探针对23株典型的有害赤潮生物进行了检测，结合流式细胞仪、荧光显微镜、荧光分光光度计对探针标记区分和识别目标藻的特异性和有效性进行定性和定量测定。结果表明，DBA可以把裸甲藻（Gymnodinium）GIXM01株与其他裸甲藻区分开：SBA、WGA和PNA探针能定性或定量地区分形态相似的裸甲藻GMDH01和TPXM01。PHA-E和SJA能分别将塔玛亚历山大藻（Alexandrium tamarense）ATDH04、ATMJ02株系与同种其他的藻株区分开：PNA也能从同种其他株系中识别塔玛亚历山大藻ATDH01，ATDH02，ATDH03株系：UEAⅠ能从同种藻株中识别塔玛亚历山大藻ATCI01．JN、ATCI01藻株；RCA120可以区分产毒水平不同的亚历山大藻属（Alexandrium）的ASPGX01和ASPGX02。DBA、SBA、PNA和LCA探针能定性和定量区分微小原甲藻（Prorocentrum minimum）PMDH01和PMXM01;而PNA探针仅能定量区分原甲藻属（Prorocentrum）PDDH01与PMXM01。用WGA探针结合流式细胞仪、荧光显微镜、荧光分光光度等检测手段可以把探针标记的目标裸甲藻GSPXM01和TPXM01从米氏凯伦藻（Karenia mikimotoi）、东海原甲藻（P.donghaiense）和微小原甲藻（P.minimum）等组成的混合样品中区分开。[中国水产科学，2008，15（2）：279-292]     

栉孔扇贝急性病毒性坏死病毒（AVNV）卵内的垂直传播途径

急性病毒性坏死病毒已被证实为是一种对养殖栉孔扇贝危害极大的病原体，探讨其传播途径是防控扇贝“大规模死亡症”的前提之一。将亲贝各放在一独立育苗水体内产卵、孵化，并进行幼虫培育。通过春季和秋季室内人工育苗，从40个独立育苗水体中，采获亲贝、卵各23个家系样品，受精卵、D形幼虫、壳顶幼虫各12个家系样品，眼点幼虫2个家系样品。采用间接ELISA法、间接免疫荧光技术和电子显微镜技术对亲贝、卵和发育各期的幼虫进行定性和定位的检测。结果发现，栉孔扇贝的性腺组织中存在病毒粒子，而卵、受精卵及各期发育幼虫体内均未检测到病毒。由此可以判断：AVNV可以感染栉孔扇贝的性腺，但并不存在卵内垂直传播的可能性。     

墨西哥湾扇贝与华贵栉孔扇贝的远缘杂交

为进一步研究扇贝属间远缘杂交的可行性,以墨西哥湾扇贝(Argopecten irradians concentricus)与华贵栉孔扇贝(Chlamys nobilis)作为亲本,建立了两种扇贝的正交组MH、反交组HM、墨西哥湾扇贝自交组MM和华贵栉孔扇贝自交组HH。对各实验组的胚胎发育速度、受精率、孵化率、D形幼虫发生率和幼虫生长速度进行比较,分析了不同温度、盐度和精子浓度对各实验组配子亲和力及合子育性的影响,并尝试运用BP神经网络模型预测杂交组浮游幼虫的生长趋势。结果表明,两种扇贝的正反杂交均可获得早期杂交子代(F_1)。从胚胎发育情况看,正反杂交组幼虫发育到D形幼虫的时间均少于两个自交对照组;其受精率、孵化率、D形幼虫发生率也低于两个自交对照组;即使在不同温度、盐度和不同精子浓度下正反交组的受精率和孵化率也均低于两个自交组。从浮游幼虫生长情况看,正反交组D形幼虫的壳长和壳高均高于两个自交组,具有显著的差异性(P0.01),表现出较明显的杂种优势。运用BP神经网络模型对正反交组的浮游幼虫进行预测,其预测值与实测值的误差率均小于4%。     

Triploid induction by hyperosmotic shock in the Yesso scallop,Patinopecten yessoensis

The triploid technology is a new frontier in shellfish aquaculture and has shown encouraging results in numerous shellfish species. We induced triploid larvae in the Yesso scallop, Patinopecten yessoensis, using hyperosmotic shock for the first time in this study. Different induction parameters, including salinity strength, treatment starting point, and the duration, were tested. The highest triploid ratio of D‐shaped larvae (72.12%) was obtained by 60 ppt salinity treatment for 20 min at the first appearance of zygote showing polar body II (PB2). A significantly faster growth rate was observed during the swimming larvae stage despite a decrease in the hatching and survival ratios. The triploid ratio decreased to 46.67%, and approximately 1.76 million triploid juveniles were harvested after 90 days of cultivation. The treatment parameters can be further optimized to improve the yield of Yesso scallop triploids.     

The effects of cadmium and copper on embryonic and larval development of ide Leuciscus idus L.

The effects of Cd and Cu on embryos and larvae of the ide Leuciscus idus were evaluated. The ide is an European cyprinid fish, natural populations of which tend to decrease. The ide is also used as a bioindicator organism to evaluate water quality. However, sensitivity of ide early developmental stages to heavy metal intoxication is not known. Fish were exposed to Cd or Cu (100 μg/L) during embryonic, larval or both developmental periods. Survival of the embryos, time of hatching, size and quality of newly hatched larvae were evaluated at the end of embryonic period. Correctly developed larvae from the control and Cd or Cu-exposed groups were transferred to clean water, Cd or Cu solutions (100 μg/L) immediately after hatching. Larval development was observed, and the larvae were photographed. Time of yolk sac resorption, onset of active feeding and swim bladder inflation were evaluated, and the measurements were done on body and swim bladder size. The results showed that exposure of embryos to Cd and Cu significantly reduced embryonic survival and increased frequency of body malformations and death in newly hatched larvae and delayed hatching. Exposure to Cd and Cu during larval period reduced larval survival, growth and delayed development (yolk utilization, beginning of active feeding and swim bladder inflation). Cadmium was more toxic to the ide embryos and larvae than copper. Exposures to metals during embryonic period alone caused adverse impact on larval performance even when larval development took place in clean water. However, exposure of embryos to Cu reduced toxic impact of metal on larvae in continuous Cu exposure compared to the non-preexposed fish, but no such an effect occurred in case of Cd exposure. The results show that even a short-term exposure to Cd or Cu during early development of ide may adversely affect recruitment of this species. Among the measured endpoints, quality of newly hatched larvae (frequency of body malformations and larvae dead immediately after hatching) and swim bladder size were the most sensitive to intoxication with both metals. Embryos were more sensitive to Cu intoxication than larvae, while in case of Cd, sensitivity of both stages was similar.     

pH对龟足胚胎和幼虫发育的影响

为探讨水体pH对龟足(Capitulum mitella)胚胎孵化和幼虫生长发育的影响,采用单因子实验的方法,在水温25-28℃条件下,研究了不同pH(5.0,5.5、6.0、6.5、7.0、7.5、8.0、8.5、9.0、9.5)对龟足胚胎的孵化时间、孵化率和幼虫存活率、变态率的影响.结果表明:pH为5.0时,胚胎不...     

Possible cytotoxic effects of the dinoflagellate, Gyrodinium aureolum, on juvenile bivalve molluscs

Juveniles of eight commercially important species of bivalve molluscs (Spisula solidissima, Argopecten irradians, Crassostrea virginica, Mytilus edulis, Mya arenaria, Ostrea edulis, Mercenaria mercenaria, Placopecten magellanicus) were exposed in the laboratory to the commonly occurring dinoflagellate, Gyrodinium aureolum. Histological analyses of gut tissues indicated that the impact of G. aureolum on the shellfish was species-specific. High rates of mortality were noted in the bay scallop, A. irradians, but not in other molluscan species. There were no pathological differences between control animals and animals fed G. aureolum in S. solidissima, M. arenaria, or M. mercenaria. The most severely affected molluscs were C. virginica and A. irradians. C. virginica did not exhibit differences in digestive gland parameters between control and experimental animals; however, several animals did show significant mantle and gill lesions. Bay scallops exhibited decreased height of absorptive cells and increased lumen diameter after exposure to Gyrodinium suggesting, at least, poor food quality of Gyrodinium. Evidence of toxic effects was not identified in the digestive gland. Several bay scallops also showed variable amounts of inflammation in the kidney associated with protozoal infestations and variable amounts of predominately rod-shaped bacteria within the urinary space. Aquaculturists, especially of scallop species, should monitor for the presence of G. aureolum. Given its large size (25-30 m), G. aureolum could be filtered from incoming water to hatcheries, thus avoiding mass mortalities of spat and juvenile scallops.     

Developmental changes in drinking rate and ion and water permeability during early life stages of euryhaline tilapia, Oreochromis mossambicus, reared in fresh water and seawater

Euryhaline tilapia (Oreochromis mossambicus) can breed either in fresh water (FW) or in seawater, and the developing embryos and larvae withstand direct transfer from FW to SW or vice versa, before the development of osmoregulatory organs. In the study, developmental changes in drinking rate and ion and water permeability were examined after transfer of the embryos from FW to SW. Drinking was measured by accumulation of fluorescent beads in the intestine and also by 14C-dextran accumulation he whole body. The drinking rate increased steadily from 2 to 10 days after hatching, and the larvae in SW consistently imbibed more water than those in FW. The diffusional water permeability remained low during embryonic stages but increased markedly after hatching in both FW and SW; the water permeability was consistently less in SW-adapted embryos and larvae than those in FW. In contrast, the turnover rates of chloride ion in SW were 50 to 100 times greater than those in FW, and increased markedly after hatching. The drinking rate as well as ion and water permeability of the tilapia embryos and larvae in FW and SW were comparable with those reported for stenohaline species. These results clearly indicate that different water and ion regulatory mechanisms are operating in the tilapia embryos and larvae in FW and those in SW to convey their strong euryhalinity.     

Production of a base population and its responses to F1 selection in the bay scallop, Argopecten irradians irradians Lamarck (1819)

A base population of the bay scallop, Argopecten irradians irradians Lamarck, was produced by crossing two cultured bay scallop populations. After 1 year of rearing, the top 10% truncation selection of the top 10% ( i =1.755) was carried out in the base population of about 1300 adults. A control parental group with a an identical number to the select parental group was randomly selected from the entire population before isolation of the select parental group. The result showed that, at the larval stage, the growth rate of larvae in the selected line was significantly higher than that of the control ( P <0.05), and that the genetic gain was 6.78%. Owing to the lower density of control at the spat stage, the mean shell length of the control line was larger than that of the select line at day 100. When the same density was adjusted between two lines in the grow-out stage (from day 100 to 160), the daily growth rate of the selected line was significantly higher than that of the control line ( P <0.05). Survival of the select line was significantly larger than that of the control line in the grow-out stage. In conclusion, the results obtained from this experiment indicate that selective breeding from a base population with a high genetic diversity established by mass spawning between different populations appears to be a promising method of genetic improvement in bay scallop, A. irradians irradians Lamarck.     

温度对玫瑰无须鲃胚胎发育的影响

为了探索温度对玫瑰无须鲃(Puntius conchonius)胚胎发育的影响,将玫瑰无须鲃的受精卵置于不同温度培养容器中进行孵化观察。结果显示,在温度为18～32℃的环境条件下,玫瑰无须鲃的胚胎均能孵化,最适孵化温度范围为24～28℃。如果温度高于32℃或低于18℃时,玫瑰无须鲃的胚胎不能孵出仔鱼。在温度为34℃时,胚胎发育到原肠胚晚期全部死亡,温度为16℃时,胚胎发育停止于神经胚期,孵化时间随温度的升高而缩短,呈幂函数相关。玫瑰无须鲃胚胎发育的生物学零度为12.35℃,有效积温为419.40℃.h。