盐度对条石鲷胚胎发育的影响

为了确定条石鲷胚胎孵化的适宜盐度,在试验水温为23.0℃～25.2℃条件下,设置了8个盐度组进行条石鲷胚胎孵化试验,研究了盐度对条石鲷胚胎发育的影响。结果表明:低盐度和高盐度对胚胎有持续性伤害,均可造成胚胎和卵黄球在卵裂期收缩而死亡,一部分胚胎在原肠期之后收缩死亡;低盐度可造成初孵仔鱼畸形率增加,主要引起仔鱼脊柱"L"形和"C"形弯曲,而高盐度可导致胚体胚孔关闭以后尾部的畸形发育;通过分析各盐度组的孵化率、仔鱼畸形率和盐度之间的关系,得出健康仔鱼比例(PHL)和盐度(S)的关系式为PHL=-0.0018S2-0.1135S-0.8853(R2=0.948),以PHL70%为适宜孵化盐度范围,以PHL90%为最适孵化盐度范围,由此确定在23.0℃～25.2℃条件下,条石鲷的适宜孵化盐度范围为21～42(PHL70%),最适为30～33(PHL90%)。     

卵形鲳鲹胚胎及早期仔鱼耗氧量的研究

运用SKW-3微量呼吸仪对卵形鲳鲹(Trachinotus ovatus)胚胎和早期仔鱼的耗氧量进行测定,研究温度、盐度及pH的变化对胚胎耗氧量和Cu²⁺、Cd²⁺等重金属离子对早期仔鱼的耗氧量的影响。结果表明:在(25±0.5)℃条件下,卵形鲳鲹胚胎和早期仔鱼的耗氧量均随着发育时间的延长总体上呈上升的趋势,胚胎耗氧量在出膜前达到最大值,其中以原肠期和出膜期耗氧量变化最为显著。胚胎耗氧量随着温度、盐度、pH的增大而逐渐升高,在水温25℃、盐度35和pH为8时耗氧量到达最大值,随后逐渐减小。随着Cu²⁺浓度的升高,早期仔鱼耗氧量呈先增大后减小,在0.01mg·L^-1时耗氧率最大:胚胎耗氧量随着Cd²⁺浓度的升高而逐渐降低。     

扁平圆扁螺(Hippeutis complanatus)早期发育的形态观察

在水温18℃左右条件下培养扁平圆扁螺(Hippeutis complanatus),使其产卵,在光镜下观察其早期发育过程,详细描述各发育阶段的形态特征.扁平圆扁螺胚胎发育属典型的包囊幼虫发育类型,其过程共分为6个时期,即卵裂期、囊胚期、原肠期、担轮幼虫期、面盘幼虫期和仔螺形成期.胚胎于面盘幼虫晚期孵化,在水中完成仔螺形成过程,腹足从三角变为长楔形,幼虫肾退化,螺壳平伏形成仔螺.     

贝氏高原鳅胚胎和仔鱼的形态发育

通过人工授精获得受精卵,对贝氏高原鳅胚胎和仔鱼的发育过程进行了观察和描述。结果表明,成熟卵淡黄色,卵径较小(直径0.94－1.10mm),遇水后产生强黏性。在水温9.0－12.8℃下,胚盘在受精后4h20min开始分裂,在19h50min和27h40min时达到囊胚期和原肠期,64h40min胚孔封闭,287h时部分胚胎开始出膜,405h30min全部出膜。初孵仔鱼全长(4.32±0.23)mm,肌节36－38对,眼和躯干部黑色素细胞明显,胸鳍原基发育良好。出膜后第5天仔鱼体侧和头部出现浓密的感觉芽。到第8天时全长(6.05±0.41)mm,卵黄吸收完全。仔鱼鳔一室和鳔二室分别于出膜后第30天和第50天形成。第55天的仔鱼全长(14.05±1.01)mm,肌节52－53对,体侧出现7－8条黑色素带,各鳍鳍条数目与成鱼基本一致,但仍有少量鳍褶存在。仔鱼的卵黄囊体积减小速度为0.027mm3/d,鱼体长度生长、鱼体长度性状间的比例关系并不相同,其中,肛后长／全长比例随胚后发育逐渐增加,由初出膜时的31%增加到最后的42％左右。     

杂色鲍的胚胎发育

杂色鲍（Ｈaliotis diversicolor Reeve）的胚胎发育分为个阶段共３２个发育期,其中,卵裂阶段有１３个时期：受精期、第１极体放出期、第２极体放出期、２细胞分裂早期、２细胞期、４细胞期、８细胞期、１６细胞期、３２细胞期、６４细胞期、１２８细胞期、桑椹期和囊胚期。胚胎发育阶段有４个时期：原肠期、担轮幼体早期、担轮幼体晚期和担轮幼体孵化瞬期、胚后发育阶段有１３个时期：担轮幼体期、面盘幼虫早期、面盘幼体中期、面盘幼体后期、匍匐幼体中期、铺匐幼体后期、围口壳幼体早期、围口壳幼体中期、围口壳幼体后期、上足分化幼体早期、上足分化幼体中期和上足分化幼体后期。幼鲍阶段有２个时期：第１呼吸孔出现早期,和１呼吸孔出现,须适宜水温范围内,随着水温升高,孵化期相应缩短,在水温１８－３４℃条件下,受精卵不同程度都能孵化,但孵化率和孵化时间则有很大差别。在水温18℃时,鲍卵从受精至开始孵化需经历11hr32min,孵化率占2.5‰,平均孵化期为26hr15min,孵化速率为0.0381,周限增长率为1.0010/hr;而在水温22℃条件下,经过7hr30min才开始孵化,平均孵化期为23hr5min,孵化速率为0.0415,周限增长率为1.0202/hr。鲍卵受精后,在水温为23.7-28.5℃、盐度为32.8‰-34.5‰（比重10223-1.0229）的条件下,只需经23－24d能发育为幼鲍（为第一个呼吸孔出现期）。     

红螯螯虾胚胎发育研究Ⅰ.胚胎外部结构的形态发生

详细研究了红螯螯虾（Ｃｈｅｒａｘ ｑｕａｄｒｉｃａｒｉｎａｔｕｓ）胚胎的外部形态发育过程。在水温２８℃的条件下,整个发育过程约需３９ｄ,顺次经历卵裂期、囊胚期、原肠期、前无节幼体期、后无节幼体期、复眼色素形成期及孵化准备期。刚孵化出的幼体在形态结构上与成体相似。     

拟赤梢鱼的胚胎发育和仔稚鱼生长特性观察

为阐明拟赤梢鱼(Pseudaspius leptocephalus)胚胎发育和仔稚鱼发育特点, 采用人工催产的方式获得受精卵, 观察分析了拟赤梢鱼胚胎发育和仔稚发育的时序特征。结果表明: 拟赤梢鱼成熟卵粒为黄色圆球形, 平均卵径为(1.77±0.20) mm, 遇水具微黏性; 在水温23℃条件下, 胚胎发育经历合子期、卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期和孵化出膜期7个阶段26个时期, 共历时47h 55min完成孵化过程。初孵仔鱼在(23±1)℃水温条件下, 经历卵黄囊期仔鱼(0—7d)、晚期仔鱼(8—26d)和稚鱼期(27—31d), 进入幼鱼期; 卵黄囊期仔鱼游泳能力差, 随着卵黄囊逐渐消耗, 体表色素斑、胸鳍和尾鳍等逐渐形成, 消化道贯通, 鳔充气; 晚期仔鱼卵黄囊完全消失, 仔鱼游泳能力增强, 开口摄食, 腹鳍形成, 皮肤透明; 稚鱼期鳞片形成并覆盖全身, 鱼体形态已逐渐与成鱼无异。拟赤梢鱼仔稚鱼阶段全长生长特性公式为TL=0.0125x2+0.3579x+6.2058 (R2=0.9953), 出膜15d内, 仔鱼生长速度缓慢, 全长日生长率仅为(0.38±0.02) mm/d, 15d后, 仔鱼生长速度变快, 全长日生长率可达(1.24±0.09) mm/d。研究初步阐明了拟赤梢鱼的胚胎发育和仔稚鱼发育的时序特征, 为拟赤梢鱼的苗种规模化繁育提供了理论基础。     

低温处理对金银花尺蠖卵和蛹的影响

将金银花尺蠖Heterolocha jinyinhuaphaga Chu的卵、蛹分别在5℃和8℃下处理1 d、3 d、5 d、7 d后,放在25℃下培养,研究低温处理对金银花尺蠖卵和蛹的影响。结果表明,低温处理对金银花尺蠖卵的发育历期和孵化率、蛹的发育历期和羽化率均有显著的影响。低温处理后,卵、蛹的发育历期比对照显著缩短,并且随着低温处理天数的增加,发育历期逐渐缩短,差异达显著水平;卵的孵化率和蛹的羽化率比对照也显著下降。经过5℃低温处理1 d、3 d卵的发育历期分别比对照缩短286 d、473 d;孵化率分别比对照下降了4234%和4967%;处理5 d、7 d的卵均不能孵化。经过8℃低温处理1 d、3 d卵的发育历期分别比对照缩短125 d、300 d;卵的孵化率分别比对照下降了3035%和4500%,处理5 d、7 d的卵也均不能孵化。经过5℃低温处理1 d、3 d、5 d的金银花尺蠖蛹的发育历期分别比对照缩短了249 d、454 d和701 d;羽化率分别比对照下降了5777%、6784%和7810%;处理7 d的蛹均不能羽化。经过8℃低温处理1 d、3 d、5 d的金银花尺蠖蛹的发育历期分别比对照缩短了133 d、354 d和549 d;羽化率分别比对照下降了3945%、5873%和7441%;处理7 d的蛹均不能羽化。     

大竹蛏胚胎发生及稚贝发育研究

在人工培育条件下,对大竹蛏(Solen grandis)胚胎发生及稚贝发育进行显微观察,探究大竹蛏胚胎及幼虫发育规律。结果表明,大竹蛏胚胎及幼虫发育过程为：受精卵、卵裂、囊胚期、原肠期、担轮幼虫、D形幼虫、稚贝。在水温为22.4℃时,受精后20~24h发育成D形幼虫,5~7d变态为稚贝,38d稚贝贝壳已具备成贝形态,壳长壳高比为2.60。从受精卵到附着所需积温为3088.79~5005.19℃?h。稚贝先形成出水管后形成进水管,最终形成“一管双孔”。壳长与壳高关系式为     

东北七鳃鳗早期发育研究

通过开展东北七鳃鳗(Lampetra morii)胚胎、卵黄囊期仔鱼和幼鱼发育研究, 系统地描述东北七鳃鳗的早期发育形态特征和生长发育规律。研究结果表明: 东北七鳃鳗的卵裂为全裂类型, 在(18±1)℃水温下, 受精卵经卵裂期、囊胚期、原肠胚期、神经胚期、头凸期、孵出前期以及孵出期, 历时11—12d孵育出仔鱼。初孵仔鱼体重为(0.00032±0.00002) g, 全长为(0.29±0.02) cm。在卵黄囊期内, 仔鱼体重和全长随日龄的增加而增长, 吻长、眼径、眼鳃间距、口笠长、鳃前长、鳃长、头长、体长、尾长和泄殖孔长均存在异速生长现象。初孵仔鱼经过约15d(卵黄囊期)发育成幼鱼, 幼鱼卵黄囊完全吸收, 消化道贯通, 形成肠道, 开始摄食。在幼鱼期, 经5 个月的培育, 幼鱼体重和全长随月龄的增加而增长, 体色逐渐加深, 5月龄幼鱼的体重和全长分别为(0.07±0.01) g和(3.87±0.32) cm。东北七鳃鳗的早期发育研究为七鳃鳗发育生物学积累基础资料, 同时也为七鳃鳗的人工增养殖提供了科学依据, 推进七鳃鳗的模式化进程。     

TOTAL CELL NUMBER AND NUMBER OF THE PRIMARY MESENCHYME CELLS IN WHOLE, 1/2 AND 1/4 LARVAE OF CLYPEASTER JAPONICUS*

Total cell number and number of the primary mesenchyme cells of 1/2 and 1/4 larvae were counted at several developmental stages after hatching in comparison with those of a whole larva, using Clypeaster japonicus as material. To obtain partial larvae, blastomeres were isolated at the 2- or 4-cell stage in Ca-free sea water and cultured in natural sea water at around 23°C. Isolated blastomeres cleaved as in situ, namely, as a part of an embryo. Although each partial embryo tended to spread into a plate, it acquired spherical shape prior to hatching of control whole embryo and developed normally in terms of both developmental rate and morphogenesis. Total cell number of a whole larva was about 620 just after hatching and increased almost linearly until i t reached 1850 at the pluteus stage. A half and quarter larvae contained roughly 1/2 and 1/4, respectively, of the number of cells of whole larva through all stages counted. Numbers of the primary mesenchyme cells in the partial larvae, however, tended to be slightly larger than a half or a fourth of that in whole larva. In whole larva, 35, 50, 56 and 58 was counted at the mesenchyme blastula, early gastrula, late gastrula and pluteus stage, respectively.     

Structural and ultrastructural analysis of embryonic development of Prochilodus lineatus (Valenciennes, 1836) (Characiforme; Prochilodontidae)

This survey was performed to characterize the embryogenesis of Prochilodus lineatus. Seven stages of embryo development were identified--zygote, cleavage, blastula, gastrula, segmentation, larval and hatching--after a period of incubation of 22 h (24 degrees C) or 14 h (28 degrees C). The following cleavage pattern was identified: the first plane was vertical (2 blastomeres); the second was vertical and perpendicular to the first (4 blastomeres); the third was vertical and parallel to the first (4 x 2); the fourth cleavage was vertical and parallel to the second (4 x 4); the fifth was vertical and parallel to the first (4 x 8); and the sixth cleavage was horizontal (64 blastomeres). At the blastula stage (3.0-4.0 h (24 degrees C); 1.66-2.0 h (28 degrees C)) irregular spaces were detected and periblast structuring was initiated. At the gastrula stage (4.0-8.0 h (24 degrees C); 3.0-6.0 h (28 degrees C)) the epiboly, convergence and cell movements, as well as the formation of embryonic layers, had begun. The segmentation stage (10.0-15.0 h (24 degrees C); 7.0-10.0 h (28 degrees C)) was characterized by a rudimentary formation of organs and systems (somites, optic vesicle and intestinal delimitation). The embryo at the larval stage (16.0-21.0 h (24 degrees C); 11.0-13.0 h (28 degrees C)) showed a free tail, more than 25 somites, an optic vesicle and a ready-to-hatch larval shape. The blastomeres at cleavage stage had disorganized nuclei indicating high mitotic activity. At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption.     

Sensitivity to chilling of medaka (Oryzias latipes) embryos at various developmental stages

As an essential step toward cryopreservation of fish embryos, we examined the chilling sensitivity of medaka (Oryzias latipes) embryos at various developmental stages. Embryos at the 2-4 cell, 8-16 cell, morula, blastula, and early gastrula stages were suspended in Hanks solution. They were chilled to various temperatures (usually 0 degrees C), kept for various periods (usually 20 min), then cultured for up to 14 d to determine survival (assessed by the ability to hatch). Embryos at the 2-4 cell stage were the most sensitive to chilling to 0 degrees C, but sensitivity decreased as development proceeded. The survival rate of 2-4 cell embryos was affected after 2 min of chilling at 0 degrees C; although the rate decreased gradually as the duration of chilling increased, 38% of them still survived after 40 min of chilling. Embryos at the 2-4 cell stage were sensitive to chilling at 0 or -5 degrees C, but much less sensitive at 5 or 10 degrees C. The survival rate of 2-4 cell embryos subjected to repeated rapid cooling and warming was similar to that of those kept chilled. When early gastrula embryos were preserved at 0 or 5 degrees C, the hatching rate did not decrease after 12 and 24h of chilling, respectively, but then decreased gradually as storage was prolonged; however, 3-10% of the embryos hatched even after storage for 10 d. In conclusion, although later-stage medaka embryos would be suitable for cryopreservation (from the perspective of chilling sensitivity), chilling injury may not be serious in earlier stage embryos.     

Sea-urchin RNAs displaying differences in developmental regulation and in complementarity to a collagen exon probe

Sea-urchin embryo RNAs of 9 kb and 7 kb hybridise with a collagen-coding probe. The delta Tm of the hybrids indicates a 70% sequence identity between these RNA regions. Both RNAs are localised in the pluteus endomesoderm, but accumulate over different developmental periods: the 9 kb RNA first appears in the blastula and reaches a maximum concentration during the gastrula stages, while the 7 kb RNA is first detected in the gastrula and is at maximal concentration in the pluteus larva. Animalization by transient exposure of the early stage embryo to Zn2+ alters the developmental profile of the 9 kb collagen mRNA in a way that is clearly different from responses of other mRNAs whose accumulations are initiated during the blastula stage (Nemer, M. (1986) Dev. Biol. 114, 214-224).     

RNA synthesis in nuclei isolated from early embryos of Xenopus laevis.

1. Rates of RNA synthesis in isolated Xenopus embryo nuclei decrease from blastula through gastrula and neurula stages to hatching tadpoles. 2. In blastula and gastrula nuclei, net synthesis of RNA continues for over 30 min, both in the presence of KCl at 0.4 M and in its absence. In nuclei from later stages, net synthesis continues for only about 10 min in the absence of KCl. 3. At low ionic strength, RNA synthesis in all nuclei is greater with optimum Mg-2+ (6 mM) than with optimum Mn-2+ (1 mM). At high ionic strength the reverse is true. 4. An unusual feature, which gradually disappears as development proceeds, is that curves relating RNA synthesis to KCl concentration show a peak at 0.1 M KCl. In blastula nuclei, RNA synthesis is more rapid at 0.1 M KCl than at 0.4 M. 5. This peak at low ionic strength is not observed in the presence of the initiation inhibitor rifamycin AF/013. It is concluded that the peak arises from initiation of RNA synthesis by an excess of RNA polymerases bound non-specifically to the isolated nuclei. The residual synthesis, representing elongation of chains that were initiated in vivo, still declines as development progresses. 6. In blastula nuclei, over half of the RNA synthesis is effected by polymerase II (inhibited by alpha-amanitin), the proportion remaining roughly constant with increasing ionic strength. In neurula nuclei, the proportion rises from about one-half to three-quarters. The initiation-dependent peak in blastula and gastrula nuclei is contributed by both alpha-amanitin-sensitive and alpha-amanitin-resistant enzymes.     

鳙鱼ARISTICHTHYS NOBILIS早期发育的一些生物化学上的变化

本实验第一部分对鳙鱼卵及胚胎在不同的发育时期蛋白质合成的速度进行了研究,实验采用微量克氏定氮法,对鳙卵从未受精卵到受精卵、尾芽期和出膜期,共测定了十三个不同的发育时期。实验结果表明了在鱼的不同胚胎发育时期蛋白质合成速度有着明显的差异。 实验的第二部分对鳙鱼胚胎发育过程氨基酸组成和氨基酸含量进行了测定,其结果显示出鳙鱼卵和胚胎的各发育时期氨基酸的组分十分相似,但氨基酸的含量在各个时期是有差异的。     

Lipid peroxidation in embryos and larvae of the sea urchinStrongylocentrotus intermedius

Lipid peroxidation (LP) and glutathione content were studied at different developmental stages of the sea urchinStrongylocentrotus intermedius: egg cell, fertilization, 4 blastomers, blastula, hatching, gastrula, prism, pluteus. A high rate of LP in the total membrane fraction of sea urchin embryos and larvae at the stages from the egg cell to hatching was observed at enzymatic and nonenzymatic activation of LP. The LP rate was significantly reduced at the gastrula stage and at subsequent stages, there was practically no further development of the process. The glutathione concentration remained unchanged at different stages. The alterations in LP seem to reflect participation of free radicals in regulation of individual development.     

Free radical processes in the embryogenesis of Anura]

The localization of free radical processes and changes in their level during the common frog development have been studied by means of grafted copolymerisation and autoradiography. The maps of distribution of relative concentrations of free radicals were obtained for the beginning of cleavage, blastula, gastrula and neurula. The distinct regionalization was found in the beginning of cleavage: the concentration of the free radicals in the cortical layer and dorsal half of embryo is lower than in the central area and ventral half, resp. At the early blastula stage this regionalization is preserved in its general features. The region of embryo characterized by active free radical processes corresponds to the presumptive endo- and mesoderm in the period of inductive interaction. The possible participation of regional changes in oxidative metabolism in the fertilized egg in the determination of cytoplasmic localization of morphogenetic potencies is discussed. At the later stages there were variations observed in free radicals concentration, which are discussed as being related to the determination and morphogenesis of some rudiments of embryo. A local rise of free radicals concentration was also found out in the eye rudiment just before the onset of its components differentiation.     

美洲鲥胚胎及仔稚鱼的发育

对美洲鲥(Alosa sapidissima)早期生活史阶段的生长发育特征进行了观察和测量, 描述了胚胎和仔、稚鱼的生长发育特征。美洲鲥受精卵球形、无油球, 为沉性卵, 卵径2.85-3.28 mm。在水温20.3℃-21.9℃孵化条件下, 经过82h 孵化出膜, 根据其胚胎发育过程的形态特征, 胚胎发育分为受精卵、卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期和出膜期7 个发育阶段。美洲鲥初孵仔鱼全长为(8.56±0.36) mm, 其卵黄囊体积为(4.57±0.77) mm3。1 日龄仔鱼脑部发育明显, 口张开, 肛门开通, 胸鳍形成。2 日龄仔鱼卵黄囊体积(0.71±0.23)mm3, 只有刚孵化的15.54%。3 日龄仔鱼经过1d 的混合营养期, 卵黄被完全吸收, 4 日龄仔鱼完全营外源性营养, 卵黄囊的体积(V)随孵化时间(h)的变化方程为V=4.1583e?0.0356h(R2=0.9901)。此后, 背鳍鳍条、尾鳍鳍条、臀鳍鳍条和腹鳍鳍条相继在晚期仔鱼出现, 9 日龄仔鱼尾椎开始弯曲, 21 日龄仔鱼尾椎弯曲完成。27 日龄鱼鳞开始形成, 到33 日龄稚鱼全身披鳞, 个体发育进入幼鱼期, 仔稚鱼期间的生长模型方程为: TL=0.0049D2+0.5091D+9.2578 (R2=0.9885, TL 为全长, D 为日龄)。       

Embryonic development of the sea urchin after low-temperature preservation

The sea urchin embryos were cooled to -196 degrees by two-step freezing with the use of 1-1.5 M dimethyl sulfoxide as a cryoprotectant. The embryos were equilibrated with the cryoprotectant for 20-30 min at 0 +/- 2 degrees. At -7 degrees ice crystallization was induced and the embryos were cooled to -38-42 degrees at a rate of 6-8 degrees /min. The embryos were then transferred into liquid nitrogen. The embryos were thawed in a water bath at 19 degrees. No less than 90% of the embryos frozen at the stages of blastula, gastrula, or pluteus were capable of recovery and normal development. The length of cryopreservation did not affect the survival of the embryos.