瓦氏黄颡鱼的胚后发育观察

2002年5~6月,在四川省泸州市、合江县分数批收集到长江野生瓦氏黄颡鱼(Pelteobagrusvachelli)亲本,通过人工催产、人工授精获得受精卵,对其胚后发育过程进行了观察。瓦氏黄颡鱼的胚后发育过程可以分为卵黄囊仔鱼、晚期仔鱼和幼鱼3个阶段。初孵仔鱼淡黄色,肌节40对,平均全长5.2mm。水温20~22℃时,孵出后第3d口张开;第7d开始摄食;第9d卵黄吸尽,此时鱼苗平均全长12mm,卵黄囊仔鱼阶段结束。晚期仔鱼阶段的仔鱼,胸鳍、尾鳍、臀鳍、背鳍、腹鳍先后发育,至鳍褶消失时晚期仔鱼阶段结束。经过30d的生长和发育,进入幼鱼阶段;此时平均全长达37mm,其形态特征和生态习性均与成鱼相似。     

壮体沙鳅早期发育及红水河来宾江段资源补充量评估

2017年4月中旬至8月底于红水河来宾江段进行鱼卵、鱼苗监测, 发现壮体沙鳅Botia robusta (Wu, 1939)为所采集鱼卵中的主要优势种。研究对壮体沙鳅卵进行培育、观察并详细记录了14个重要发育期的形态特征。卵膜无黏性, 卵膜径平均为6.8 mm; 鳔一室期, 鱼苗体长为7.1 mm, 身体肌节数为33对。孵出后第20日, 鳍条完全形成、体表色素整体形成, 进入稚鱼阶段。该江段壮体沙鳅的产卵繁殖主要集中在5—6月, 当年补充群体总量估计达2.23×108颗, 然而伴随下游大藤峡水利枢纽的建成其年际补充量将受到严重威胁; 将壮体沙鰍卵的单位捕捞努力量与主要环境因子进行相关性分析, 发现仅水温变动与其产卵动态呈显著性相关（P<0.05）, 现场水温记录表明:水温达到20℃时开始产卵, 水温超过28℃时产卵量明显减少, 且最适产卵温度为22℃。     

野生玫瑰果实发育过程中种子的细胞组织结构和内源激素变化对其休眠性的影响

以吉林珲春自然群落的野生玫瑰(Rosa rugosa Thunb.)为试验材料,探究野生玫瑰在果实形成过程中种子的发育及休眠性的形成和变化。选取青果期(1~35 d)、转色期(35~60 d)、红果期(60~75 d)的果实及种子,结合形态学、组织细胞学观察法及高效液相色谱技术,对果实各发育时期的种子形态、种胚及内果皮的发育进行研究,并分析种子内源激素含量变化与果实发育、种子休眠之间的关系。结果表明:果实和种子在青果期(1~35 d)时发育速度最快,种胚在花后24 d发育完全,种子不存在形态休眠。花后24 d内果皮开始沉积木质素并逐渐木质化,种子开始产生机械休眠。种子激素含量的变化与果实的发育、转色及内果皮的木质化密切相关,种子内源GA3和ABA含量在青果期(1~35 d)达到峰值,内源IAA含量在果实转色期(35~60 d)达到最大值,高浓度的ABA含量是种子尚未脱离果实时便已进入生理休眠的主要原因。     

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。     

高等植物胚胎的发育生物学研究——Ⅸ.稻胚发育过程中呼吸强度及细胞色素氧化酶活力的变化

前文已报道稻胚在分化发育过程中细胞分裂增殖迅速,生物大分子物质的含量亦相应增长(唐锡华等1980;朱治平等1980;覃章铮和唐锡华1982),而且淀粉在胚乳及胚中积累时还可能通过β淀粉酶而降解被发育中的胚所利用(高锦华和唐锡华1982)。为了研究这个过程中的生理变化,本文作者结合稻胚分化器官原基及积累贮藏物质各发育期的进展,研究了胚的呼吸强度与细胞色素氧化酶活力的变化规律;因为呼吸强度标志着胚体总的生理活性变化,而细胞色素氧化酶是呼吸链中末端氧化的一个重要酶,它直接关系到高能键ATP的形成。过去已有作者(1960;夏叔芳等1966)证明;水稻幼苗或籽粒中有末端氧化酶系统存在;而且较幼嫩籽粒中糖的末端氧化主要是通过金属末端氧化酶类,乳熟后磷酸戊糖支路(HMP)及非金属氧化酶类逐渐加强。夏叔芳(1964)还指出水稻种子成熟时,稻胚的呼吸强度并不下降。因此有必要在了解稻胚分化发育过程中胚呼吸作用的变化的同时,研究稻胚中金属末端氧化酶中的细胞色素氧化酶活力变化规律,以便了解稻胚分化发育过程中胚细胞分化发育与物质代谢的能量来源。     

侧金盏胚和胚乳发育的细胞胚胎学研究

利用石蜡切片技术对毛茛科植物侧金盏胚及胚乳发育进行了研究,以明确其胚胎发育的特征,为毛茛科植物的系统研究提供资料。结果表明:(1)侧金盏胚的发育属于柳叶菜型,胚乳发育为核型;初生胚乳核的分裂早于合子的第一次分裂。(2)种子成熟时,种胚尚未分化完全,尚处于球形胚后期或心形胚早期阶段,整个胚发育大约需要50~60d。(3)侧金盏种子存在明显的形态生理休眠现象,经后熟作用逐渐完成种胚的分化与生长,形成子叶形胚;侧金盏种子在相同处理条件下胚分化和发育的速度存在差异。     

小鼠不同阶段胚胎玻璃化冷冻保存的比较研究

采用玻璃化冷冻法对ICR、C57BL/6、DBA~*C57BL/6杂交F1代三种品系小鼠的不同阶段胚胎进行冷冻保存,比较胚胎解冻后形态良好率、体外发育率和移植后的出生率,结果表明解冻后各品系小鼠胚胎从2细胞到桑椹胚形态良好率在75%以上,其中8细胞胚胎形态良好率在83%以上,而囊胚的形态良好率仅在40%左右。解冻后胚胎体外培养的发育率随胚胎发育阶段的提高而提高,桑椹胚的发育达93%以上。体外受精2细胞冷冻胚与体内受精2细胞冷冻胚比较,二者形态良好率差异无显著意义(74%∶75%),但体内受精冷冻胚的发育率明显高于体外受精冷冻胚(76%:40%,p<0.01);胚胎经过三次反复冻融后形态良好率无显著差别;冷冻2细胞胚移植后的受孕率与仔鼠出生率分别达64%和40%,但均低于新鲜2细胞胚。     

稀有鮈鲫眼的形态发生研究

详细观察和描述了稀有鮈鲫眼发育的形态变化,并分别对视网膜发育早期神经层、色素上皮层的厚度及眼发育后期视网膜的总厚度进行了测量。结果表明:稀有鲫眼的发生始于神经胚时期形成的眼原基,与两栖、哺乳类动物不同,其眼原基是由间脑向左右伸出的对称外突实体;在尾芽期眼原基向腹侧弯曲、侧向伸长,随后开始内陷,在尾泡期形成视杯。眼原基外层与外胚层紧贴的部分将发育为视杯的内层、神经视网膜,而眼原基其余部分将分化为视杯的外层、视网膜色素层。在尾泡期之后,视网膜色素层停止有丝分裂开始形成色素颗粒,此时视网膜神经层开始分化。视网膜这两层结构在发育早期分化的有序进行可能与早期胚胎头部内空间以及附近的间充质细胞有关。从神经胚期到尾泡期,视网膜色素层厚度由42.3±0.8μm减小到4.8±0.4μm,视网膜神经层厚度从37.1±0.2μm增加到43.7±0.6μm,而从尾鳍期到孵出期视网膜总厚度从42.7±1.2μm逐渐增加到98.3±2.1μm。与所有脊椎动物一样,稀有鲫眼的视网膜分化也是按照由内向外的顺序进行,晶状体、角膜及其他结构在孵出时已基本发育完全。     

增殖细胞核抗原在小鼠肾小体发育中的表达

目的研究小鼠肾小体发生发育过程中增殖细胞核抗原(PCNA)的表达水平.方法采用免疫组织化学方法结合光学显微镜技术.结果比较发育不同阶段肾小体PCNA表达时,处于原始阶段,即Ⅰ期和Ⅱ期肾小体内PCNA阳性率最高;而随着肾小体生长发育和成熟,即Ⅲ、Ⅳ、Ⅴ期肾小体,PCNA的表达会逐渐减弱.在比较不同胚龄及生后日龄的同期肾小体时发现,Ⅰ期、Ⅱ期肾小体内PCNA阳性细胞率不因胚(日)龄的增加而变化;而Ⅲ期、Ⅳ期和Ⅴ期随着胚龄的增加,特别是生后日龄的增加阳性率逐渐下降.结论细胞增殖在肾小体发育的整个过程中是由高逐渐减低.生后龄肾内生长阶段肾小体的PCNA阳性率明显低于胚龄时生长阶段肾小体.     

珠江下游广东鲂体长-体重关系和肥满度的年间变化北大核心CSCD

本研究通过对2010至2018年珠江下游肇庆江段广东鲂(Megalobrama terminalis)的生物资料调查,探究了其体长-体重关系以及肥满度及年龄结构年间变化趋势。结果表明,2010至2018年珠江下游肇庆段广东鲂种群的体长及5+龄以上个体占比率总体呈现下降趋势。2010至2018年珠江下游广东鲂种群体长-体重幂函数相关的条件因子a为0.011~0.004,异速生长因子b为2.816~3.261。广东鲂种群在2010、2011和2014年呈现负异速生长,而在2013及2015至2018年份表现出正异速生长。2010至2018年珠江下游广东鲂种群肥满度总体呈现出上升趋势。此外,2010至2018年珠江下游肇庆段日平均水温20℃以上天数占比率呈现逐渐上升趋势,而洪峰数量减少且相对集中。本研究发现广东鲂异速生长因子与日平均水温和径流量呈现一定线性正相关关系,揭示栖息地环境与广东鲂生长潜在的关联性。持续的高捕捞压力加快了广东鲂种群生长速度,并导致了该种群负异速生长。珠江禁渔期制度实施及其栖息地水温变化,可能是珠江下游广东鲂种群肥满度逐渐升高的原因。     

Dirofilaria macrodemos and D. panamensis spp. n. (Nematoda: Filarioidea) from Central and South Americal sloths

Two new species of Diorfilaria, Dirofilaria macrodemos and Dirofilaria panamensis, are described from the subserosa of Central and South American sloths. Dirofilaria macrodemos, described from the three-toed sloth, Bradypus tridactylus, in Guyana, is characterized and differentiated from other dirofilarias by its length (female 214mm, male 64mm), relatively long tail (female 140 micron, male 110 micron), and the number and distribution of the caudal papillae (7 pairs) in the male. Dirofilaria panamensis, parasite of the two-toed sloth, Cholopeus hoffmanni, in Panama, was previously described as Dirofilaria incrassata by Caballero (1947), but can be distinguished from both D. macrodemos and D. incrassata on the basis of body size (female 66 mm long by 360 micron wide, male 34 mm long by 250 micron wide), tail length (female 80 micron, male 80 micron), and number (6 pairs) of caudal papillae in the male.     

四种杂交组合奥尼罗非鱼及其亲本的生长对比研究

通过RFID电子标记注射、跟踪和生长性状测量,对2个奥利亚罗非鱼品系(ZZ、AA)、2个尼罗罗非鱼品系(XX、EE)自交群体及其杂交奥尼罗非鱼4个群体(XZ、XA、EZ、EA)进行生长对比研究,罗非鱼亲本来自国家罗非鱼产业技术体系研发中心。结果表明:XZ、XA、EZ、EA四个奥尼罗非鱼群体雄性率均达94%以上,全长、体长、头长、体高等性状特征值显著高于亲本品系(P<0.05),奥尼罗非鱼的生长速率相对其亲本品系具有一定的优势,同时4个奥尼群体间生长性状特征值也存在显著差异(P<0.05);生长性状相关分析显示罗非鱼各配组群体的体质量与尾柄长相关性较低(0.690—0.846),与全长、体长、体高、体厚相关性较高;对罗非鱼各配组群体的比例性状进行主成分分析,第1主成分主要代表BS、HS、CDS、BWS性状特征,第2主成分主要代表TS、HS、CLS性状特征,通过第1、第2主成分作图可将AA与其他6个罗非鱼配组群体有效区分。     

Cell lineage analysis in ascidian embryos by intracellular injection of a tracer enzyme: I. Up to the eight-cell stage

Cell lineages during development of ascidian embryos were analyzed by injection of horseradish peroxidase as a tracer enzyme into identified cells at the one-, two-, four-, and eight-cell stages of the ascidians, Halocynthia roretzi, Ciona intestinalis, and Ascidia ahodori. Identical results were obtained with eggs of the three different species examined. The first cleavage furrow coincided with the bilateral symmetry plane of the embryo. The second furrow did not always divide the embryo into anterior and posterior halves as each of the anterior and posterior cell pairs gave rise to different tissues according to their destinies, which became more definitive in the cell pairs at the eight-cell stage. Of the blastomeres constituting the eight-cell stage embryo, the a4.2 pair (the anterior animal blastomeres) differentiated into epidermis, brain, and presumably sense organ and palps. Every descendant cell of the b4.2 pair (the posterior animal blastomeres) has been thought to become epidermis; however, the horseradish peroxidase injection probe revealed that the b4.2 pair gave rise to not only epidermis but also muscle cells at the caudal tip region of the developing tailbud-stage embryos. The A4.1 pair (the anterior vegetal blastomeres) developed into endoderm, notochord, brain stem, spinal cord, and also muscle cells next the caudal tip muscle cells. From the B4.1 pair (the posterior vegetal blastomeres) originated muscle cells of the anterior and middle parts of the tail, mesenchyme, endoderm, endodermal strand, and also notochord at the caudal tip region. These results clearly demonstrate that muscle cells are derived not only from the B4.1 pair, as has hitherto been believed, but also from both the b4.2 and A4.1 pairs.     

An experimental breakage ofReissner's fibre in the central canal of the pike (Esox lucius)

Summary The spinal cords of newly hatched pike (Esox lucius) fry were divided into two pieces by transverse cuts. After periods of different lengths, the appearances of the brokenReissner's fibres were investigated anatomically. The fibre normally terminates in the caudal end as a secretory accumulation, a caudal mass. After the operation this mass gradually disappears, apparently through the spinal cord wall cells. The new termination of the broken fibre, in front of the scar, forms a new caudal mass. This fact indicates thatReissner's fibre is a secretory transport mechanism.Supported by a grant from the Swedish Natural Science Research Council.     

长吻(鱼危)幼鱼发育的研究

长吻(鱼危)的幼鱼发育共分为仔鱼前期、仔鱼期和稚鱼期三个阶段。本文记述的是幼鱼发育各阶段外部形态的变化和内部器官的建成以及不同时期出现的集群、摄食、避光等生物学特性。对提高鱼苗成活率,培育出优质健壮的苗种有指导意义。       

鲂属团头鲂、三角鲂及广东鲂种间遗传关系及种内遗传差异

采用形态判别、同工酶分析和RAPD分析相结合的方法,从3个层次研究分析了鲂属团头鲂、三角鲂和广东鲂的种间亲缘关系和种内遗传差异。结果表明：（1）3种鲂在形态可数性状上差异不显著,而可量性状与框架分析揭示团头鲂与三角鲂亲缘关系较近,它们同广东鲂差异较大;（2）团头鲂和三角鲂均具有MDH同工酶的s-Mdh-D位点,而广东鲂未见,引物S11扩增的结果在3种鲂间均显示种的特异性,这些同工酶谱带和DNA扩增带可作为3种鲂的种间分子标记;（3）3种鲂种间亲缘关系在三个研究层面上相互吻合：即广东鲂和头鲂、三角鲂差异较大,亲缘关系较远,而三角鲂和团头鲂之间差异小,亲缘关系较近;（4）同工酶和RAPD分析揭示,三角鲂种内遗传多样性显著地高于广东鲂和团头鲂。     

Factors affecting the survival of dace, Leuciscus leuciscus (L.), in the early post-hatching period

Young dace fry were stocked into nylon mesh cages at densities ranging from 0·044 to 7·230 1^-1, and the cages anchored in a backwater area where the fry gathered naturally. The fry began feeding on small organisms drifting into the cages 2-4 days after hatching. The growth rate of the fry was inversely proportional, and the death rate directly proportional, to initial density. Soon after the exhaustion of endogenous food reserves (as determined from unfed fry), there was a period of massive mortality at the highest initial densities, probably due to starvation. After 20 weeks, the cages stocked at the two highest initial densities contained the lowest biomass of fry. Transfer of fry to cages with a larger mesh size produced increased growth and 46% survival over 20 weeks at the lowest initial density. These fry reached an overwintering length of 35·5 mm compared with 48·0 mm for naturally occurring fry.     

Embryonic and larval development of Thai Pangas (Pangasius sutchi Fowler, 1937)

The embryonic and larval development of Thai pangas was investigated during peak (May-July 1995) and late spawning (August-October 1995) periods. The fertilized eggs are adhesive and spherical with a yellowish or greenish-brown egg capsule. The yolk sac is yellowish-brown in color and 1.20-1.80 mm in diameter. Nine hours post-fertilization, the first cleavage stage, embryonic shield, head, tail region, neural grooves and somites were evident. The incubation period ranges from 24-36 h at a temperature of 20-30 degrees C. The newly hatched larvae are quite transparent and light yellowish in color with a body length of 2.98-3.10 mm. Eye pigments appear and the heart starts to work within 12-14 h of hatching. In 1-day-old pro-larvae, the mouth becomes well developed; barbules are elongated, prominent and look like tiny threads. The yolk sac is fairly well absorbed and the palatine teeth are fully developed during the 3 day pro-larval stage. At the end of 12 days of larval development, the stomach becomes functional and aerial respiration starts. After 2 weeks, the young fry is well-developed, and is of an adult appearance, that is, measuring up to 13.56 mm in length.     

Identification of development and tissue-specific gene expression in the fathead minnow Pimephales promelas, Rafinesque using computational and DNA microarray methods

The fathead minnow Pimephales promelas serves as a model organism for assessing the effects of environmental contaminants on early life stage growth and development. Yet, the utilization of genomic tools has been hindered by the lack of genome sequence and genomic information known from this model species. Utilizing published cDNA library sequences, the authors used sequence similarity to compare 4105 cDNAs isolated from fathead minnow fry (<14 days old) with over 250 000 adult cDNA sequences derived from whole body and various tissue types. The objectives of the computational subtraction were to (1) assess the extent of sequence similarity between developing and adult cDNA libraries and (2) predict which cDNA clones are expressed only in developing organisms. The results of the computational predictions were assessed through the construction of a development‐specific DNA microarray targeting all 4105 sequences in the fry cDNA library as well as 56 known mRNAs in P. promelas. Gene expression was determined by comparing total RNA isolated from fry with total RNA isolated from adult samples (whole animal, kidney, liver, brain, ovary and testes). The results showed that 1381 of the targeted fry cDNA sequences (34%) displayed expression across all sample comparisons, and of these, only 166 genes were found to harbour fry‐specific expression (i.e. no expression in adult samples). Of note, 69% of the genes computationally predicted to be fry specific were found across all experimental results; yet, only 27% of the computationally predicted fry‐specific sequences were experimentally confirmed to be fry specific. An important result was the identification of many novel mRNA sequences specific to the developing minnow, which lack homology with any other known sequence. In addition, the study results included tissue‐specific expression in adult samples. These results demonstrate the capabilities and limitations of inter‐library sequence comparisons as a predictor of gene activity in non‐sequenced organisms and tissues, as well as DNA microarray gene expression studies in non‐sequenced organisms.