黄鳝一种新的生殖腺发育状况报道

早在六十年前,刘建康就报道过黄鳝存在着自然性逆转现象[1]。在随后的几十年里,众多的学者对于黄鳝性逆转开展了较为广泛的研究[2—8]。目前一般认为黄鳝属于雌性先熟的雌雄同体鱼类,其性别发育为单方向进行,雌性发育阶段→间性发育阶段→雄性发育阶段。黄鳝雌性成熟发育第一次性周期内黄鳝个体全部表现为雌性发育,性成熟产卵后,卵巢内卵细胞败育,卵巢结构逐渐退化,与此同时雌性生殖细胞开始发育,通过雌雄间性发育过渡到雄性发育[2、3、7]。在这一发育程序中尚未有黄鳝同一个体生殖腺中精、卵巢结构均为成熟发育的报道。作者在对于黄鳝生殖…     

未产卵雌性黄鳝的性转变

为探讨产卵是否为雌性黄鳝(Monopterus albus Zuiew)性转变的必经过程, 研究分析了实验室内从受精卵或幼苗开始养殖至不同时间段的黄鳝性腺组织学状况, 采用性腺活检技术跟踪了34月龄雌性黄鳝性腺发育变化, 并以免疫组织化学方法探讨了黄鳝不同发育状态性腺中增殖细胞核抗原(PCNA)的分布。在养殖过程中, 实验黄鳝没有出现产卵现象或者繁殖行为。在5月龄黄鳝中, 间性占比13.3%, 雄性占比20.0%; 在12月龄(1龄)黄鳝中, 雄性占比17.6%; 34月龄(3龄)黄鳝中, 间性占比12.8%, 雄性占比8.5%。通过性腺活检技术对36条34月龄雌性黄鳝性腺发育变化进行了为期1个月的跟踪研究, 结果表明, 16.7%的雌性黄鳝发生了性转变, 性腺发育到间性阶段。黄鳝间性早期性腺生殖褶增厚, 部分细胞呈现明显PCNA免疫阳性, 包括间质细胞、精原细胞和初级精母细胞。上述结果提示, 产卵并非雌性黄鳝发生性转变的必经过程; 黄鳝性转变初期, 性腺结构变化包括生殖褶中间质细胞和精原细胞的发生和增殖。     

三种果蝇精巢生殖干细胞半衰期的研究

果蝇精巢生殖干细胞(Germline stem cells,GSCs)的数量伴随衰老呈现递减趋势。本文以两种野生型果蝇品系Oregon、W1118以及Stat基因突变体的精巢为研究材料,采用免疫荧光染色技术,标记果蝇精巢Hub组织及生殖干细胞,研究了室温(25℃)条件下三种果蝇羽化后六个时间点(第1、15、30、45、60、75 d)精巢GSC的数量。结果表明,两种野生型Oregon、W1118与stat突变体果蝇羽化后第1 d的GSC平均数分别为8.55、8.60与8.15,根据曲线图得到,两种野生型果蝇GSCs半衰期均为60 d左右,而stat突变体果蝇约为30 d,两者存在显著差异,表明stat基因突变加速了果蝇精巢GSCs的衰老。     

苔藓植物生殖生态学研究

近年来苔藓植物生殖生态学研究主要集中于繁育系统、生殖代价与对策,以及不同生殖方式对种群遗传变异的影响等方面。生殖结构的原始性及其对水分的独特需求,以及雌雄异株比例较高等导致苔藓植物中有性生殖比例偏低;雌配子体很少完成整个有性生殖过程,其“真实的生殖代价”主要指雌性性表达(雌配子发生)的能耗,并且显著低于雄性性表达;基于对资源有效分配的生殖对策而导致雌性偏向及部分孢子体败育。无性生殖有利于不同生境条件下有效种群的发展与维持,其多样化的繁殖方式导致复杂的种群动态。苔藓植物具有较高的种群遗传多样性,生殖方式与种群遗传变异无直接因果关系,孢子与无性繁殖体不同的散布能力对于种群间遗传分化具有一定的影响。     

哺乳动物雌性生殖干细胞研究的质疑、进展及挑战

传统观点认为雌性哺乳动物在出生后即失去产生新生殖细胞的能力,但近年来研究人员在多种出生后的哺乳动物卵巢内成功分离并培养到一类生殖细胞,这类细胞具有自我增殖和分化成卵母细胞的能力,从而确认出生后的哺乳类动物卵巢内存在雌性生殖干细胞的事实。该文拟从雌性生殖干细胞的研究历史及发现,生殖界对雌性生殖干细胞的质疑,近年来雌性生殖干细胞的研究进展和应用,以及当前雌性生殖干细胞研究所存在的不足、所面临的机遇与挑战作一评述。     

精原干细胞与睾丸生殖衰老的研究进展

雄性睾丸内精子的生成及其质量随年龄增长逐渐降低。精原干细胞是精子生成的起点,其数量和质量决定了精子的生成,而精原干细胞niche是调节精原干细胞自我更新与分化的重要因素。在衰老过程中,干细胞微环境退化,精原干细胞自我更新和分化失衡,被认为是衰老导致睾丸生殖功能衰退的的主要因素。本文将综述衰老引起的精原干细胞与niche变化及其对生殖的影响相关研究进展。     

牛雄性生殖系干细胞的体外诱导分化

雄性生殖系干细胞(Male germ-line stem cells, mGSCs)是一群具有高度自我更新能力和分化潜能的细胞, 是雄性成体内唯一可复制的二倍体永生细胞。转基因技术与雄性生殖系干细胞异体及异种移植技术相结合, 将会为克隆动物、转基因动物生产及一些人类遗传性疾病的基因治疗提供新的机遇与途径。本试验采用组合酶消化和选择贴壁法, 对5月龄、6月龄牛胎儿及新生牛雄性生殖系干细胞体外培养及分化进行了研究。试验结果显示, 睾丸支持细胞对雄性生殖系干细胞体外增殖、分化所必需的, 同时对数期睾丸支持细胞对雄性生殖系干细胞贴壁、增殖与分化效果明显; 共培养16 d后, 牛雄性生殖系干细胞分化为长形精子细胞, 试验建立了牛雄性生殖系干细胞体外诱导培养分化体系。     

外源性甲基睾丸酮对雌性和间性黄鳝性腺发育的影响

本文研究了大剂量外源雄性激素（甲基睾丸酮,MT）对活检后的雌性和雌雄间性黄鳝发育的影响。我们应用色拉油溶解外源雄性激素对雌性和雌雄间性黄鳝进行腹腔注射,采用石蜡组织切片法,对MT对活检后的雌性和雌雄间性黄鳝性腺发育的影响进行组织学研究。试验未得到具有生殖能力的性逆转雄鱼,但发现了一些十分有趣的结构,将为进一步揭开黄鳝性逆转之谜奠定了一定的基础。结果如下：① MT可促进雌鳝卵母细胞退化,但不能使卵巢完全解体; ② MT可促进雌性和间性黄鳝性腺生殖板扩大、伸展,但不能使间质细胞增生;③ MT可促进雌性和间性黄鳝性腺生殖板上出现“中空小叶”,这种结构可以分成两种类型,即Ⅰ型“中空小叶”(“HL-Ⅰ”)和Ⅱ型“中空小叶”(“HL-Ⅱ”),Ⅱ型“中空小叶”可能是非正常发育下产生的生精小叶;④ MT对雌雄间体早期的黄鳝的雄性生殖细胞的发育有促进作用,对雌雄间性晚期的黄鳝可促进其生精小叶内的雄性生殖细胞外排,而形成另一类型的“中空小叶”。 ⑤ MT对雌雄间体黄鳝的作用强于对雌性黄鳝的作用。     

季节性变化对雌性恒河猴生殖功能的影响

目的　研究季节性变化对雌性恒河猴生殖功能的影响。方法　采用随机抽样法和放射免疫测定法 ,分析了不同时期雌性恒河猴性皮肤变化、月经周期和生殖激素变化的特点。结果　 ( 1)性征的季节性变化 :在生殖季节雌性恒河猴几乎都出现性皮肤反应 ,出现比较规则月经周期 ,在非生殖季节只有部分雌性恒河猴出现性皮肤反应 ,月经周期不规则 ,行经频率低 ,有的出现长时间的闭经 ;( 2 )生殖激素的季节性变化 :在生殖季节促性腺激素和性类固醇激素的分泌水平都出现周期性的变化 ,而非生殖季节促性腺激素和性类固醇激素的分泌水平没有显著的差异。结论　雌性恒河猴性皮肤变化、月经周期和生殖激素存在明显的季节性差异 ,这种差异导致了雌性恒河猴生殖功能的季节性变化     

低浓度84消毒液对小鼠生殖生理的影响

目的：观察低浓度84消毒液对小鼠生殖生理的影响。方法将72只KM小鼠随机分为3组,即：0.5％84消毒液组（ A组）、2.0％84消毒液组（ B组）和生理盐水组（ C组）,每组24只,雌雄各半,各组每天1次灌胃给予相应药物,连续9周。阴道涂片镜检观察雌性小鼠的动情周期。9周后,观察雄性小鼠的精子畸形率;并用ELISA法测定小鼠血清中性激素的水平;并取睾丸（或卵巢）、心、肝、肺、肾进行组织学观察。结果与C组比较,A和B组小鼠体重差异无显著性（ P ＞0.05）;血清性激素水平差异无显著性（ P ＞0.05）;雌性小鼠动情周期差异无显著性（P ＞0.05）;组织学观察未见异常;与C组比较,A组小鼠精子畸形率差异无显著性（P ＞0.05）,B组小鼠精子畸形率显著增高（ P ＝0.041＜0.05）。结论0.5％84消毒液对小鼠的生殖生理无明显影响,在实际使用中要严格控制消毒液浓度。     

The structure of the gonad during natural sex reversal in Monopterus albus (Pisces: Teleostei)

A detailed study on the structure of the gonad of Monopterus albus was made as a basis for analysis of gonadal steroids in this sex-reversing teleost. Two types of males were identifiedand their existence appeared to be a result of the difference in gonadal ontogeny among the individuals in natural populations. The germinal area of the gonad, the gonadal lamellae, exhibited à zoned nature with regard to the location of the female and male germ cells. Observations suggested that the male germ cells originated from gonia pre-existing in the inner zone of the gonadal lamellae before sex reversal. Natural reversal of sex in this protogynous hermaphrodite was found to be usually a postnuptial event and was always accompanied by loss of ovarian tissue and by development of interstitial (Leydig) cells. In the mesogonial region of the gonadal wall, peculiar mesenchyme cells were found, their significance remained uncertain.     

The atretic structures in the gonads of the rice-field eel (Monopterus albus) during natural sex-reversal

The gonad of the protogynous, hermaphroditic teleost, Monopterus albus were examined histologically at monthly intervals throughout one year. In particular, the epithelium of the maturing follicles of the female and the atretic follicles in the female, intersex and male were studied. Atretic follicles were common in the gonads and were classified as corpora atretica types 1 to 5 according to histological criteria. In addition, other regressive structures were observed in the gonads of some males. The histology and the frequency of occurrence of the atretic structures in the three sexual phases is described and discussed.     

不同性别黄鳝六种组织中LDH同工酶电泳谱的初步研究

本文报告了运用聚丙烯酰胺凝胶圆盘电泳研究不同性别黄鳝的血清、心肌、骨骼肌、肝、肾和生殖腺等六种组织器官中ＬＤＨ同工酶。结果表明六种不同组织中ＬＤＨ同工酶谱各不相同,具有明显的组织特异性。在不同性别中某些同一种组织的ＬＤＨ同工酶谱也发生变化,这说明决定黄鳝ＬＤＨ同工酶表达的因素在不同性别中有差异。     

鄱阳湖黄鳝的生长特征

以基舌骨和脊椎骨作为年龄鉴定的材料,研究了鄱阳湖黄鳝(Monopterus albus)种群的生长特征.结果表明,种群的年龄结构分别为:雌性1～5龄,雄性2～6龄,2～5龄为黄鳝性别的过渡期(间性).2～4龄为优势年龄组,占渔获物的89.75%,相对应的体长为30～50 cm,体重为30～120 g.体长(L)与体重(W)的关系为:W=0.000 4L3.2601(♀);W=0.001 4L2.9008(∮).按生长指标值分析,阶段生长可以明显地划分为两个时期,即2龄前的生长迅速期和2龄后的生长稳定期.拟合的Von Bertalanffy生长参数分别为雌性L∞=78.5 Cm,k=0.174 02/y,t0=-1.203 2 Y,W∞:602.01 g;雄性L∞=102.3 cm,k=0.118 45/y,t0=-1.310 1 Y,W-=947.32 g;生长特征参数分别为ψ=3.030 3(♀)和ψ=3.093 4(∮);雌雄个体生长差异显著.     

Seasonal changes in the distribution of gonadal lipids and spermatogenetic tissue in the male phase of Monopterus albus (Pisces: Teleostei)

The gonad of Monopterus albus undergoes cyclical changes after the reversal of sex from female to male. The seasonally variable events include a prenuptial accumulation of cholesterol-positive lipid droplets in the cytoplasm of the interstitial cells when spermatogenetic activity is resumed in late February and early March. The development of the interstitial Leydig cells reaches a maximum in May just before spawning. There occurs a sudden depletion of the interstitial lipids during the breeding season in June at a time when the male animals exhibit active nuptial behaviour. After spermiation, the old interstitial cells degenerate, and during the succeeding phase of gonadal inactivity, become replaced by a new generation from connective tissue cells in the interstitium of the gonadal lamellae which gradually accumulate lipoidal material.
The lobular cycle comprises a postnuptial accumulation of amorphous intralobular lipids which become completely cleared in February when active spermatogenesis is restored. Spermatogenesis resumes shortly after spawning, but only advances as far as primary spermatocytes during the postnuptial period of inactivity.
The authors conclude that, as far as the seasonal variations in gonadal lipid distribution is concerned, the cycles in the gonad of the hermaphroditic teleost, M. albus , conform to the same pattern as those of the gonochoristic seasonal breeders studied.     

黄鳝性逆转时生殖腺的组织学与超微结构的变化

黄鳝由雌转雄性时,其生殖腺滤泡细胞变得肥大和充满分泌物,卵母细胞的微绒毛、线粒体与放射带退化,卵黄液化。滤泡细胞吞噬卵黄颗粒并消化吸收后,最后形成类胡罗卜素瘤。随着卵巢的退化,精细胞与精巢逐渐形成。     

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。       

Cloning and Characterization of a Rice Field Eel vasa-Like Gene cDNA and Its Expression in Gonads During Natural Sex Transformation

The vasa (vas)-related gene encodes an RNA helicase protein member of the DEAD-box family and plays key roles in germ-cell formation in higher metazoans. Using degenerate PCR and RACE, we cloned the vasa gene of the rice field eel (Monopterus albus), which is homologous to the Drosophila vasa gene. We named it ma-vas (Monopterus albus vas). Ma-vas encodes a protein of 618 amino acids, which contains all of the known characteristics of vasa homologs. RT-PCR analysis revealed that ma-vas was exclusively expressed in the gonads of the female, intersex, and male. During gonadal natural sex reversal, ma-vas is expressed in oocytes at all stages of oogenesis, in degenerating oocytes of ovotestis, and in spermatogonia and spermatocytes at early stages. The vasa positive signal was also observed in the peripheral layer of late ovary. It was not found, however, in that layer of the testis. Alkaline phosphatase (AKP) staining on the ovary and testis also indicated that some cells had differentiational potential in the peripheral layer of the ovary, suggesting that spermatogonia might arise from cells with AKP and vasa-positive staining in the peripheral layer of the female gonad.