Preliminary results of the in vivo studies on ovarian resorption in carp (Cyprinus carpio L.)

Oocyte resorption in the ovaries of sexually mature carp, which did not spawn, was investigated using a method of sampling ovaries in vivo . A 2-year study revealed that a portion of the oocytes had undergone a slow resorption while the basic mass of the ovaries, throughout the experiment, consisted of the oocytes similar to those of stage IV of sexual maturity. At the same time no growth of the oocytes of the earlier maturation stages was found. The condition of the ovaries in the females studied indicated their complete infertility, at least for three successive spawning periods.     

Asynchronism in sterlet oocyte development under industrial conditions

Under natural conditions in the course of gametogenesis, the asynchronism in oocyte development in fish ovaries is observed on early stages of gonad maturation and mostly in species with batch spawning. When investigating gametogenesis in sterlet under conditions of a warm-water farm (Konakovsky sturgeon farm), rather uniform development of gametes is noted; asynchronism occurs in separate individuals and also in fishes grown under conditions of recirculating aquaculture system (RAS) at a constant high water temperature.     

A study of the kinetics of microsporogenesis in Campelia zanonia (L.) H.B.K.

During maturation, microspores pass through a series of morphologically distinguishable stages or compartments. A study has been made of the systematic fluctuations in the frequency of microspores in these compartments, when plants are grown under rigidly controlled conditions. A new approach to the construction of cumulative flux rate curves is described; these give the number of cells passing the compartment boundaries per unit time. The curves obtained indicate that simple models, which assume constant flux rates and compartment transit times, will not explain the observations. It is evident that not only do microspores mature at different rates, but that the maturation rate of individual microspores varies during the developmental sequence. The overall process may be controlled by the intimate relationship which exists between the microspores and the tapetal periplasmodium in the Tradescantiae.     

Sex differentiation and aspects of gametogenesis in shortnose sturgeon Acipenser brevirostrum Lesueur

Shortnose sturgeon Acipenser brevirostrum gonad samples were collected from industry-reared fish and wild broodstock at various developmental stages to elucidate patterns of gonadal differentiation and maturation. Genital ridges, containing germ cells, were present in 26 day-old fish and distinct gonads were present by day 54. Sturgeon gonads are known to consist of two tissue types (adipose and gametogenic) and both were present at 72 day. Anatomical differentiation of gonads occurred by 6 months and was advanced by 15 months. Ovaries had distinct lamellae while testes remained non-lamellate. Gonial proliferation had occurred by 15 months, but the cells were not identifiable as spermatogonia or oogonia. Small white 'pinhead' oocytes were macroscopically visible in ovaries as early as 36 months. At 43 months ovaries were clearly organized, with some areas containing only immature oocytes and other containing oocytes apparently developing as cohorts. Individual fish showed considerable variation: the level of development remained unchanged at 84 months in some females, while others showed clear progression towards sexual maturation at 48 months. Sperm cells were present in males as early as 52 months. Advanced development of ovarian follicles was observed only in biopsies of re-conditioned broodstock of wild origin. In the year before spawning, the most advanced oocytes became pigmented, the chorion thickened, the nucleus (germinal vesicle) migrated towards the micropyle complex at the animal pole, and ovulation occurred in May under appropriate environmental conditions.     

Histo-chemical mapping of phosphomonoesterases in the gonads of Notopterus notopterus and Colisa fasciatus during different seasons. Part II. Adenosine triphosphatase and glucose-6-phosphatase

Histochemical techniques described by McManus (1960) have been applied in the fishes, Notopterus notopterus and Colisa fasciatus, for the study of Glucose-60phosphatase and adenosine triphosphatase in the four stages of gonads in different seasons. It has been observed that the activity of adenosine triphosphatase is more intense in comparison to the activity of Glucose-6-phosphatase in all the stages i.e. I (immature), II (maturing), III (mature) and IV (spent) of the gonads in both the fishes. The general tendency of the adenosine triphosphatase and Glucose-6-phosphatase distribution in the gonads are much more remarkable in stage II in comparison to stage I, III and IV. The stage I seems to be the stage of synthesis of these enzymes. In stage III and IV, these enzymes show the tendency of declination with the time period. The possible role of these enzymes seems to be the transport of glucose across the cell membrane involving phosphorylation and dephosphorylation which depend on the different stages of gonad maturation.     

两种发育型鱼类卵母细胞成熟过程中促精核发育现象的研究

采用实验细胞学技术,比较研究了红鲤精核在雌核发育鱼类(银鲫)和两性融合发育鱼类(红鲤、彩鲫)卵母细胞成熟各阶段中的发育状况,结果表明:在两性融合发育鱼类中,当卵母细胞发育到胚泡破裂期吋,精核开始解凝发育,及至第一次成熟分裂中期后阶段,高度解凝的精核才开始原核化,相应地,在雌核发育银鲫中,精核也只有在与胚泡物质接触后,才能开始解凝,并且在三极纺锤体形成后期初步原核化,但与两性融合发育鱼类相比,精核的原核化程度明显降低。这些实验结果初步揭示,在两性融合和雌核发育鱼类卵中均可产生促精核解凝和原核化的两类因子(SNDFs和SPDFs),其中SNDFs的活性表达起始于卵母细胞胚泡破裂时期,而SPDFs活性则产生于第一次成熟分裂中期后或三极纺锤体形成后阶段,并且两性融合发育鱼类卵中的SPDFs活性远远高于雌核发育鱼类卵母细胞。     

A STUDY OF THE KINETICS OF MICROSPOROGENESIS IN CAMPELIA ZANONIA (L.) H.B.K.

During maturation, microspores pass through a series of morphologically distinguishable stages or compartments. A study has been made of the systematic fluctuations in the frequency of microspores in these compartments, when plants are grown under rigidly controlled conditions. A new approach to the construction of cumulative flux rate curves is described; these give the number of cells passing the compartment boundaries per unit time. The curves obtained indicate that simple models, which assume constant flux rates and compartment transit times, will not explain the observations. It is evident that not only do microspores mature at different rates, but that the maturation rate of individual microspores varies during the developmental sequence. The overall process may be controlled by the intimate relationship which exists between the microspores and the tapetal periplasmodium in the Tradescantiae.     

萍乡肉红鲫的性腺发育研究

萍乡肉红鲫(Pingxiang red-transparent crucian carp,Carassius auratus L.)是在江西省萍乡地区分布的天然三倍体鲫突变体经人工选育后获得的遗传性状基本稳定的后代,具有两性生殖和雌核生殖两种生殖方式.研究以F5代萍乡肉红鲫为材料,自孵化后每满1个月开始取性腺,观察了其卵巢1周年性成熟和精巢的发育过程,结果表明萍乡肉红鲫的性腺为1年成熟类型.卵巢发育进程町以分为6个时期,卵母细胞发育相应可分为6个时相.统计了卵巢成熟系数周年变化,体重为95 g左右的雌性萍乡肉红鲫,其成熟卵巢的成熟系数约为(11.73±2.8)%,成熟的卵母细胞内充满卵黄,相对怀卵量为(3018±310)粒/g.萍乡肉红鲫精巢属于小叶型,在精小叶中可观察到不同发育阶段的生殖细胞.由精原细胞分裂而来的仞级精母细胞经分裂增殖,产生次级精母细胞并最终发育成为精子.萍乡肉红鲫的精巢发育程序与普通鲫鱼和鲤鱼相似,卵巢和精巢的发育过程基本同步,孵化后50日龄内性腺分化不明显,到70日龄左右开始出现雌雄分化,3月龄发育为第1期,4-5月龄发育为第2期,6-7月龄发育至第3期,7-10月龄可见第4期卵巢,1年即可成熟产卵,精巢可排出精液.结果表明,该鲫鱼突变体的性腺发育与普通二倍体鲤(鲫)鱼的性腺发育方式类似.     

Ovarian development in the Amazonian red discus, Symphysodon discus Heckel (Osteichthyes: Cichlidae).

The Neotropical red discus fish, Symphysodon discus, originates from the Amazonian basin and has a discoid body. Although this species is popularly used in aquaria and is exported as an ornamental fish, it has not been intensively studied. The purpose of this work was to study the morphological and histological aspects of the ovarian development in the red discus. Forty females of S. discus of varying body sizes and different stages of gonadal development were used in this study. The ovaries were weighed and examined macroscopically in order to observe the maturation stages. Histological staining of hematoxilin-eosin was used for microscopic observations of the ovaries. Macroscopic observations showed immature, maturing, mature and partially spent stages of ovarian development. Microscopic examination of the ovaries revealed five stages and five phases of ovarian development. The ovaries of the mature females showed all the different phases of oocyte development, indicating the multiple spawning habit of this species.     

Ovarian development of a river catfish Hemibagrus nemurus (Valenciennes, 1840) in captivity

Hemibagrus nemurus is a riverine catfish with high economic and nutritive values. Investigations on ovarian development of this fish were carried out to determine the mode of ovarian development and describe the oocyte developmental stages. Histological studies were done on ovaries using light microscopy and scanning electron microscopy. Fish were sampled monthly for a period of six months (August 2009 to January 2010). The mean oocyte diameter (OD) ranged from 871 ± 161.41 μm to 1,167 ± 26.77 μm and the highest OD was in November. Oocyte size-frequency distribution showed a polymodal distribution. The mean gonadosomatic index (GSI) ranged from 1.14 ± 0.87% to 7.06 ± 1.40% and highest GSI was in November. The ovaries exhibited three phases of oocyte growth, which were primary growth, secondary growth and maturation phases. Based on histological criteria, the oocyte developmental stages were divided into seven stages as chromatin nucleolar, early perinucleolar, late perinucleolar, cortical alveolar, vitellogenesis, mature oocyte and germinal vesicle migration stages. All the seven stages of oocyte development were observed in the ovaries. Oogonia were always present throughout the developmental stages. The ovaries had more than two stages of oocyte development. This is the first report on the mode of ovarian development of H. nemurus. These findings indicated that H. nemurus has asynchronous mode of ovarian development and is capable of spawning several times in a year under favourable conditions.     

多倍体银鲫F系bmp15不同等位基因的分子特征、基因组结构和表达模式

为探究骨形态发生蛋白15(Bone morphogenetic protein 15, bmp15)在银鲫(Carassius gibelio Bloch) F系卵巢发育过程中的表达特征, 研究采用cDNA末端快速扩增(RACE)方法首先从银鲫F系卵巢cDNA中克隆了2个bmp15部分同源基因(Homeologs), 将其命名为Cgbmp15a和Cgbmp15b, 它们各自具有3个不同等位基因。不同脊椎动物Bmp15蛋白序列多重比对和系统进化树均表明, 银鲫为异源六倍体, 在其进化历程中发生了两轮多倍化, 其中早期的异源多倍化整合了来自2个原始祖先的染色体组, 导致银鲫和鲫的四倍体共同原始祖先基因组中包含bmp15a和bmp15b; 随后第二轮同源多倍化最终导致银鲫存在6个bmp15等位基因。bmp15基因及其邻近基因同线性分析表明, 银鲫在形成异源多倍体后, 其基因组发生了复杂的变化, 包括bmp15邻近基因的丢失。Cgbmp15a和Cgbmp15b均主要在卵巢中表达, 在皮质泡期卵母细胞中表达量最高; 无论是在银鲫成体组织还是不同发育阶段的卵子中, Cgbmp15a的表达水平显著高于Cgbmp15b的表达水平。在孕酮激素DHP体外诱导银鲫F系GV1期卵母细胞6h后, Cgbmp15a开始上调表达, 诱导8h后达到最高表达水平, 随后下降; 而Cgbmp15b在诱导8h后表达水平有微弱上调, 随后下降。上述的结果表明, Cgbmp15a和Cgbmp15b在银鲫F系成体组织和不同发育和成熟阶段的卵子中, 均表现出偏性表达的特征, 暗示Cgbmp15a在银鲫的卵母细胞发育和成熟中起着主要作用。     

Hira基因产物在银鲫和彩鲫卵子发生过程中的动态变化

为进一步研究Hira基因在卵子发生和雌核发育过程中的作用,通过原位杂交和免疫荧光定位的方法检测了Hira mRNA和蛋白质在雌核发育银鲫和两性生殖彩鲫卵子发生过程中的动态变化。结果表明,银鲫和彩鲫卵子发生过程中Hira基因转录产物的变化基本一致,在Ⅰ期卵母细胞的细胞核中大量表达,至Ⅱ期卵母细胞时转至细胞质中均匀分布,在Ⅲ期卵母细胞中,杂交信号逐渐移向细胞的周边,到Ⅳ期时随着卵黄物质大量积累,杂交信号几乎不见。HIRA蛋白在银鲫和彩鲫卵子发生过程中的变化略有差别。HIRA蛋白在银鲫Ⅰ期卵母细胞中没有表达,在Ⅱ期卵母细胞的细胞质中有弱表达,在Ⅲ期早期卵母细胞的周边有强烈表达;而在彩鲫Ⅰ期卵母细胞中就有HIRA蛋白的弱表达,至Ⅱ期时HIRA蛋白在细胞质中大量表达,Ⅲ期早期卵母细胞的细胞质中有弱表达。在银鲫和彩鲫Ⅲ期末和Ⅳ期卵母细胞中都很难观察到荧光信号。Hira mRNA和蛋白质在银鲫和彩鲫早期卵母细胞中有较强表达,且在银鲫和彩鲫卵子发生过程中没有显著差异,说明其可能对于脊椎动物卵子发生和减数分裂没有显著影响,而是在受精和/或胚胎发育过程中起作用。       

Effects of diet supplementation with carp ovary on gonad differentiation and growth of the European eel

Treating elvers of European eel Anguilla anguilla with mature carp ovary for 3–6 months during early growth induced female differentiation in 51·6–66·7% of treated animals compared with c . 5% in controls. The treatment also induced differentiation of ovaries in eels <13 cm L _T and a higher number of Syrski organs with ambisexual characters, and was most effective when administered at an early growth stage. The results could be attributed to the natural steroid content of the carp ovary. The total weight of treated animals at the end of the farm experiment was 84·7% higher than controls. The specific growth rate for weight was significantly higher in female yellow eels than in males, for both control and treated groups. The enhanced growth was related to induced feminization. A diet supplementation with mature carp ovary could be a good approach to control of sex differentiation and growth in eels.     

Oogenesis of paliya <Emphasis Type="Italic">Salvelinus alpinus</Emphasis> complex (Salmonidae) during its breeding under fish-farm conditions

A histological study of oogenesis of paliya Salvelinus alpinus complex (from larvae aged 3 weeks after hatching to the age of 3 years and 9 months) has been carried out. The fish was bred in tanks of the Federal Center of Fish Genetics and Selection (FCFGS, Ropsha, Leningrad oblast). Three-week-old larvae had primordial cells and gonia of the first orders in rudimentary gonads. Sex differentiation was completed and development of ovarian plates started in young fish aged 3.5 months. There were already previtellogenic oocytes in fish ovaries at this age. The morphology of the circumnuclear zone in previtellogenic oocytes of all stages, which appear as the age of the fish increases, as well as the morphology of oocytes of the period of trophoplasmatic growth, are described. In FCFGS conditions, paliya females aged 3 years and 9 months did not mature or oocytes degenerated in mature females. Only after a year, normal spawn was obtained from mature females.     

Gonadal maturation,fecundity, spawning,and timing of reproduction in the mud snail,Cerithidea cingulata,a pest in milkfish ponds in the Philippines

Summary

Gonadal maturation, spawning, fecundity and timing of reproduction of the snail Cerithidea cingulata in a brackish water pond in Molo, Iloilo, Philippines, are described. Snails 4–41 mm in shell length were sampled monthly from May 1997 to May 1998; 25% were <25 mm, 67% were 20–30 mm, and 8% were >30 mm. The sexes are separate and could first be distinguished at 15 mm. Males are aphallic, have narrower shells than females of the same length, and have bright yellow-orange testes overlying the digestive gland deep inside the shell. Females have more robust shells, an ovipositor at the right side of the foot, and yellow-green ovaries overlying the digestive gland. The sex ratio was one male to two females in the pond population studied. Gonadal maturation was monitored by means of gonadosomatic index (GSI, gonad weight as a percent of visceral weight); maturation stages were based on the gonad appearance (immature, developing, mature) and histology (immature, developing, mature, redeveloping). GSI increased with snail size, and reached 16% in a 33-mm female. The smallest mature males and females were 18–19 mm, and most snails >20 mm were mature, spawning, or redeveloping. Histological sections showed all stages of gametogenesis in mature male snails. The oocyte size-frequency distributions in mature females showed mostly mature oocytes and secondary oocytes, but also oogonia and primary oocytes. GSI and the frequency of snails at different maturation stages varied over the year. Both GSI and the frequency of mature snails were highest during the summer months, April to August. Nevertheless, mature snails occurred throughout the whole year, as did mating and egg-laying. Fecundity (= number of oocytes >70 pμ) increased with size in mature females 2041 mm; an average 25-mm female produced about 1,500 oocytes and larger females produced a maximum of about 2,500 oocytes. Eggs strings laid on the pond bottom were 45–75 mm long; an average 64-mm string contained 2,000 eggs 210+20 pm in diameter. The density of eggs strings was highest (80–120/m²) during March-September. Eggs hatched after 6–7 d into planktonic veligers, which in turn settle on the pond bottom 11–12 d later as juveniles. Juveniles 2–6-mm long were most abundant in the pond during August-October.     

The cloning of Dmc1 cDNAs and a comparative study of its expression in different ploidy cyprinid fishes

Dmc1 (disrupted meiotic cDNA) is a functionally specific gene, which was firstly discovered in yeast and then found to encode a protein required for homologous chromosome synapsis during the process of meiosis. In this investigation, we cloned the partial cDNAs of Dmc1 of diploid red crucian carp, Japanese crucian carp, common carp, triploid crucian carp and allotetraploid hybrids by using a pair of degenerate primers based on the conservative sequence of amino acids of the DMC1 protein in yeast, mouse and human. The full length cDNAs were then obtained by rapid amplification of cDNA ends (RACE). Our data showed that the full length cDNAs of Dmc1 in the three diploid fishes are all 1375 bp long, while it is 1383 bp long in triploids and 1379 bp long in allotetraploids. And despite of the variation in length, all the cDNAs encode a protein of 342 amino acids. A high homology of 97.3% of the DMC1 protein can be drawn by comparing the amino acid sequences in the three diploids, which is also of 86%, 86% and 95% similarity to human, mouse and zebrafish, respectively. A comparative study of the expression pattern of Dmc1 was carried out by RT-PCR using specific primers against the same se-quences of coding regions in different ploidy cyprinid fishes, from which it was showed that Dmc1 was expressed only in gonads of these five kinds of fishes. The expression pattern of Dmc1 in both ovaries and testes from different ploidy fishes within breeding season was also studied by Real-time PCR, and the results showed that the expression of this gene was greatly different among the three different ploidy fishes, which was the highest of triploid and lowest of allotetraploids. The histological sections data showed matured gonads of both diploid red crucian carp and allotetraploids in breeding season, although the latter demonstrated a higher maturation, and no gonadal maturation could be observed in triploids. In conclusion, we suggest that Dmc1 is specifically expressed in the period of meiosis in all the ploidy cyprinid fishes and directly related with the development of gonad in a manner of ploidy-independent way. And further, the high expression of Dmc1 in female triploids might be associ-ated with abnormal meiosis and sterility.     

尼罗罗非鱼性腺发育的研究

湖南地区生长于池塘环境的尼罗罗非鱼(Tilapia nilotica),性成熟日龄是110—130天,雄性比雌性普遍早熟20天。精细胞的发生能够完成由精原细胞到精子的全部发育过程,同样,卵细胞的发生也能完成由卵原细胞到卵子的全部发育过程。初级卵母细胞处于Ⅲ时相阶段时,可由包被卵周的滤泡细胞分泌产生放射膜,但放射膜不在动物性极形成受精孔,也无精孔细胞的分化,证实尼罗罗非鱼是属于非受精孔受精类型。初级卵母细胞由Ⅲ时相发育到Ⅳ时相是非同步性的,产后卵巢的组织学结构为第Ⅳ期,卵巢系数在繁殖季节可出现三次高峰,证实尼罗罗非鱼是属于多次产卵类型。通过对精巢组织学的研究,发现尼罗罗非鱼的第Ⅰ期精巢是自然两性嵌合体。       

Selection of follicles, preculture oocyte evaluation, and duration of culture for in vitro maturation of equine oocytes

Equine oocytes (n = 537) were collected from slaughterhouse ovaries (n = 118 mares) by scraping the internal follicular wall. Preculture record was made of the appearance of oocyte investments (no cumulus, corona radiata only, compact cumulus, expanded cumulus), appearance of cytoplasm (homogeneous, condensed heterogeneous/fragmented), and nuclear maturation stages (germinal vesicle, germinal-vesicle breakdown, metaphase I, metaphase II, degenerated). There was no difference between follicles > 30 mm and follicles < or = 30 mm in the preculture frequency distribution among the 5 nuclear stages; 96% were at either the germinal vesicle or germinal-vesicle breakdown stages. Oocytes from follicles 5 to 30 mm were cultured in modified TCM-199 for 18, 24, 36 and 48 h. Postculture nuclear maturation classifications were immature (germinal vesicle, germinal-vesicle breakdown, and metaphase I), mature (metaphase II or secondary oocyte), and degenerated. The frequency distribution of oocytes among the 3 postculture maturation classifications changed (P < 0.05) at 18 h (15% mature oocytes), changed (P < 0.05) further at 24 h (55% mature oocytes), with no additional change for 36 or 48 h. The only preculture cytoplasm group that affected the postculture results was the heterogeneous/fragmentation group which had a high proportion of postculture degenerated oocytes (67%); however, only 4% of oocytes were in this group. Luteal status of the mare had an effect (P < 0.05) on the frequencies of the maturation classifications, but not enough to be useful in selecting oocytes. Consistency of the follicle and the type of oocyte investment did not alter significantly the maturation frequencies. The frequency of degenerated oocytes after culture was high under the following conditions: 1) diameter of the follicle from which the oocyte was selected was 5 to 10 mm (44% degenerated oocytes), 2) the largest follicle per pair of ovaries was < or = 10 mm (63%), and 3) the mare was pregnant (66%). These results were probably related to the reported high frequency of atretic follicles in the 5- to 10-mm population. In summary, oocytes from individual follicles < or = 10 mm or from follicles in which the largest follicle per mare was < or = 10 mm were the poorest candidates for in vitro maturation.     

Comparative investigation on spindle behavior and MPF activity changes during oocyte maturation between gynogenetic and amphimictic crucian carp

The spindle behavior and MPF activity changes in the progression of oocyte maturation were investigated and compared with cytological observation and kinase assay between gynogenetic silver crucian carp and amphimictic colored crucian carp.MPF activity was measured by using histone H1 as phosphorylation substrate.There were two similar oscillatory MPF kinase activity changes during oocyte maturation in two kinds of fishes with different reproductive modes,but there existed some subtle difference between them.The subtle difference was that the first peak of MPF kinase activity was kept to a longerlasting time in the gynogenetic silver crucian carp than in the amphimictic colored crucian carp.It was suggested that the difference may be related to the spindle behavior changes,such as tripolar spindle formation and spindle rearrangement in the gynogenetic crucian carp.     

广西鲮鱼的生物学及其养殖

本文对鲮鱼的食性、年龄、生长和繁殖进行了研究,并对渔业生产提出了建议。鲮鱼以浮游植物为主要食料。在水温14.6—29.4℃时食欲旺盛。当水中溶氧量0.24—0.65毫克/升时,绝大部分个体停止摄食,而溶氧量在0.99毫克/升以上时,摄食强度很大。见到的最大个体:雌鱼体长595毫米,体重4,100克,10龄;雄鱼体长580毫米,体重3,850克,9龄。鲮鱼能在大王滩水库中自然繁殖。鲮鱼人工繁殖季节以5月初至6月中旬较适宜;催产时水温以22—29℃为好,注射催产剂的效应时间一般为4.5—6小时。见到的性成熟最小个体:郁江鲮鱼雌体长273毫米,体重525克,雄体长275毫米,体重415克;池养鲮鱼雌体长247毫米,体重366克,雄体长235毫米,体重291克。根据群众经验,一般池塘中鲮鱼每亩放养1,000尾,鲮与鲢的放养比例以3∶1较好,以鲮鱼为主体的池塘则每亩放养1,500—2,000尾较好。