共查询到20条相似文献,搜索用时 9 毫秒
1.
The development of the female Drosophila reproductive system 总被引:2,自引:0,他引:2
2.
橙黄豆粉蝶生殖系统形态学研究 总被引:5,自引:1,他引:5
解剖并描述了橙黄豆粉蝶Colias fieldii Ménétriés的生殖系统结构。结果表明:橙黄豆粉蝶雄性内生殖器包括精巢(睾丸)、2个贮精囊、2条输精管、1对复射精管、2根附腺和单射精管。其中2个睾丸体彼此密接似单一器官包被在半透明的睾丸膜中,单射精管较长且分化为形态不同的4段。外生殖器包括抱器瓣、阳茎及其附属结构;雌性内生殖器由1对卵巢、2根侧输卵管、1根中输卵管、肾型受精囊、附腺、外生殖腔及产卵孔组成。卵巢左右对称,每个卵巢具4根多滋式卵巢管。外生殖器包括导精管、囊导管、交配囊及其附属结构、前后表皮突和肛突。 相似文献
3.
目的:探讨磁处理水对家免睾丸、附睾重量以及精子活力、沃纱、密度的影响。方法:新西兰雄性大白免36只,随机分为实验组和对照组。对照组饮用自来水,实验组饮用磁处理水,磁处理水每天更换,实验进行90天。光镜下检测每只家免附睾尾精子密度,精子活力,精子活率,最后将睾丸、附睾称重。结果:实验组与对照组比较,其睾丸附睾重量明显增加,精子密度增加14 % ,精子活力增加8% ,精子活率增加11% ,两组差异有显著性(P <0 .0 5 )。结论:实验结果提示饮用磁处理水能显著提高家免的生殖能力。 相似文献
4.
J. B. S. Haldane (Amer. Nat. 71, 337–349, 1937) argued that, in equilibrium populations, the effect of deleterious mutation on average fitness depends primarily on the mutation rate and is independent of the severity of the mutations. Specifically, the equilibrium population fitness is e−μH, where μH is the haploid genomic mutation rate. Here we extend Haldane's result to a variety of reproductive systems. Using an analysis based on the frequency of classes of individuals with a specified number of mutations, we show that Haldane's principle holds exactly for haploid sex, haploid apomixis, and facultative haploid sex. In the cases of diploid automixis with terminal fusion, diploid automixis with central fusion, and diploid selfing, Haldane's principle holds exactly for recessive mutations and approximately for mutations with some heterozygous effect. In the cases of K-ploid apomixis, diploid endomitosis, and haplodiploidy, we show that Haldane's principle holds exactly for recessive lethal mutations. In addition we extend Haldane's result to various mixtures of the above-mentioned reproductive systems. In the case of diploid out-crossing sexuals, we do not obtain an exact analytic result, but present arguments and computer simulations which show that Haldane's result extends to this case as well in the limit as the number of loci becomes large. Although diverse reproductive systems are equally fit at equilibrium, different reproductive systems harbor vastly different numbers of recessive genes at equilibrium and we provide estimates of these numbers. These different numbers of mutations may create transient selective pressures on individuals with reproductive systems different from that of the equilibrium population. 相似文献
5.
The reproductive system of the female Urodacus manicatus (Scorpionidae) is described. Situated on the ventral side of the ovariuterus tubes are buds and diverticulae belonging to three developmental phases: (1) Bud-like, rudimentary diverticulae that will form future generations. (2) Embryonic diverticulae that will house the present generation. (3) Degenerating (= 'post-partum') diverticulae that contained the previous generation of juveniles just born. The smallest buds could be identified only by scanning electron microscopy of the ovariuterus tube. The various diverticulae were counted and their dimensions were measured. Based on the average number of the embryonic diverticulae, it appears that the average number of young that can be produced by a female during a single parturition is 16.8. This number does not appear to increase significantly with the growth of the female. 相似文献
6.
This paper begins a series aimed at clarifying the structure and function of reproductive organs in Gastrotricha Macrodasyida. Morphological data are presented for Dolichodasys carolinensis sp.n. and D. delicatus sp.n. Both are elongate, have reduced adhesive organs and complex accessory reproductive organs, termed the frontal-caudal organ system. The system consists of a band of cells behind the gonads in the central body chamber. The anterior portion, the frointal organ, stores foreign spermatozoa; the posterior portion, the caudal organ, may function as a copulatory organ. The caudal organ has two canals forming a loop opening at a single ventral pore. One canal contains a spiralled secretion, the other elongated filaments that appear to be muscle cell derivatives. Systematic groupings are made for other long-bodied Gastrotricha Macrodasyida. 相似文献
7.
8.
A study was performed on freshwater gastrotrichs living in the interstitial habitat of some lakes in Latium and of Lake Garda (Italy). Thirty-two chetonotids were collected, twenty-five of which could be identified. Four are new to science (Chaetonotus (Hystricochaetonotus) benacensis, Heterolepidoderma lamellatum, Ichthydium plicatum, I. squamigerum), and two are new to the Italian fauna (Heterolepidoderma macrops, H. majus). The faunistic composition of the lakes is compared with previous data. Interstitial gastrotrichs are less varied and abundant than those of epibenthos and periphyton, but often are of taxonomical and zoogeographical interest. The presence in the interstitial of some epibenthic and periphytic species demonstrates their capacity to colonize ecologically different habitats. The grain size of the substrate was not clearly correlated with faunal richness, but there was a possible influence of the amount of the organic detritus in the sediment. Morphological analysis showed a prevalence of small sized animals, with poorly ornamentated cuticular covering and well developed locomotory ciliature, as probable adaptations to interstitial life. 相似文献
9.
Spermatogonia of the nine-banded armadillo, Dasypus novemcinctus mexicanus, were studied morphologically using light and electron microscopy and examined histochemically using light microscopy. Immature flat type spermatogonia have ovoid or irregular nuclei with loosely condensed chromatin. Free ribosomes are abundant while profiles of rough endoplasmic reticulum are scarce. Smooth endoplasmic reticulum is a prominent feature occasionally taking an unusual cylindrical form. Mature spermatogonia exhibit rounder nuclei with greater degrees of chromatin clumping. Smooth endoplasmic reticulum is no longer prominent whereas profiles of rough endoplasmic reticulum are quite common. Occasional lysosomal configurations are found in mature spermatogonia. The majority of spermatogonial cells exhibit weak to moderate reactivity when stained with the periodic acid-Schiff (PAS) reaction. Certain cells in each tubular cross section stain vividly with this reaction and the PAS positivity is removable with salivary amylase. Because of nuclear characteristics, position of the cell immediately upon the basal lamina, intensity of the PAS reaction and the relative paucity of the vividly staining cells, it is suggested that they are members of the immature spermatogonial cell line, perhaps acting as stem cells. None of the several other histochemical procedures employed was capable of selectively demonstrating these cells. 相似文献
10.
The female reproductive system plays a major role in regulating the acquisition and loss of bone by the skeleton from menarche through senescence. Onset of gonadal sex steroid secretion at puberty is the major factor responsible for skeletal longitudinal and radial growth, as well as significant gain in bone density, until peak bone density is achieved in third decade of life. Gonadal sex steroids then help maintain peak bone density until menopause, including during the transient changes in skeletal mineral content associated with pregnancy and lactation. At menopause, decreased gonadal sex steroid production normally leads to rapid bone loss. The most rapid bone loss associated with decreased estrogen levels occurs in the first 8-10 years after menopause, with slower age-related bone loss occurring during later life. Age-related bone loss in women after the early menopausal phase of bone loss is caused by ongoing gonadal sex steroid deficiency, vitamin D deficiency, and secondary hyperparathyroidism. Other factors also contribute to age-related bone loss, including intrinsic defects in osteoblast function, impairment of the GH/IGF axis, reduced peak bone mass, age-associated sarcopenia, and various sporadic secondary causes. Further understanding of the relative contributions of the female reproductive system and each of the other factors to development and maintenance of the female skeleton, bone loss, and fracture risk will lead to improved approaches for prevention and treatment of osteoporosis. 相似文献
11.
以线虫Distolabrellus veechi的卵巢和精巢为材料,用甲醇固定,DAPI荧光染料对细胞核进行染色,通过Normaski荧光显微镜对其生殖系统结构、性细胞染色体数目、体细胞染色体数目进行了观察.结果显示了该线虫雌虫和雄虫生殖细胞减数分裂Ⅰ前期的细胞核的变化特征;减数分裂Ⅰ前期丝球期雌、雄生殖细胞的二价体数目均为6;卵细胞染色体数目为6,精细胞染色体数目为5或6,其性别决定机制为XX/X0型;体细胞染色体数目为11(雄虫)或12(雌虫)[动物学报 54(3):500-509,2008]. 相似文献
12.
Mystacocarids are dioecious. Their gonopores are on the medial side of the third thoracic limb. The male's paired testes lie in the thorax and abdomen. They develop from paired rows of six small follicles dorsally. In the mature animal they fill most of the abdomen. The spermatophores develop within the follicles from spermatogonia mixed with follicle cells, which support and nourish the spermatocytes and produce the seminal fluid. The short vas deferens runs along the bottom of the testes and then continues forward to the gonopore. The vas deferens has a small group of cells near the gonopore that becomes a closure mechanism. The female has reproductive cells and also support cells that provide nutrition and form the wall of the ovary and oviduct. The unpaired female ovary begins in the third thoracic segment. During maturation, the oocytes are pushed posteriorly. The enormous mature ovum extends into a caudal pocket of the ovary. Starting with its anterior end, this ovum is extruded into the short oviduct, which extends laterally and ventrally to the gonopore. During extrusion, the pocket is reabsorbed from behind. There are no accessory structures connected to the reproductive system, nor any external specializations on the third limb. 相似文献
13.
Data on the reproductive biology of the genus Hippolyte are available from studies of Hippolyte inermis. These findings support the idea that these species are protandric hermaphrodites, exhibiting sex reversal. However, recent studies of this and other species, such as Hippolyte obliquimanus and Hippolyte williamsi, have not reported sex reversal and suggest a gonochoric condition. In the present study, histological analyses were conducted of the ovaries, testes, oviducts, vasa deferentia and the development of the male appendage. The results of this study show that the Hippolyte niezabitowskii population from southern Spain should also be viewed as a gonochoric species. The study found no evidence of sex reversals. These conclusions are also supported by information on the structure of the population and by the results of studies of the male appendage. The population structure involves different size distributions of males and of females. Size classes 2-14 exhibit substantial overlap. No evidence of sex reversal was obtained from the study of the male appendage. 相似文献
14.
R W Melvold 《Genetical research》1974,23(3):319-325
15.
Recently, it has been shown that the environment contains a large variety of chemical substances possessing estrogenic activity
(ecoestrogens/environmental estrogens). In this connection, the problem of estrogenic effects exerted by the environment on
animal ontogenesis is very important. Here, we review the available data concerning the effects of ecoestrogens on the development
of the reproductive system in mammals. We discuss issues of reproductive toxicology related to the effects of these substances
during prenatal and postnatal development, with special attention to the effect of ecoestrogens and modern reproductive technologies
on preimplantation embryonic development. 相似文献
16.
P M Wise 《Journal of steroid biochemistry》1987,27(4-6):713-719
We have investigated the role of neuroendocrine and neurochemical changes in the age-related deterioration of cyclic female reproductive function. During middle age the timing and amplitude of the proestrous and estradiol-induced LH surge is altered. We have found that the diurnal pattern of norepinephrine turnover is altered in critical hypothalamic areas known to regulate the release of LHRH. These changes may contribute to alterations in the timing and the amplitude of LH release, which may, in turn, affect the ability of rats to maintain regular estrous cycles. 相似文献
17.
18.
Recently, it has been shown that the environment contains a large variety of chemical substances possessing estrogenic activity (ecoestrogens/environmental estrogens). In this connection, the problem of estrogenic effects exerted by the environment on animal ontogenesis is very important. Here, we review that available data concerning the effects of ecoestrogens on the development of the reproductive system in mammals. We discuss issues of reproductive toxicology related to the effects of these substances during prenatal and postnatal development, with special attention to the effect of ecoestrogens and modern reproductive technologies on preimplantation embryonic development. 相似文献
19.
Silphaduang U Hincke MT Nys Y Mine Y 《Biochemical and biophysical research communications》2006,340(2):648-655
Antimicrobial activity was detected in the ovary and oviduct tissues of healthy mature White Leghorn hens, Gallus gallus. Two antimicrobial proteins were purified to homogeneity using acid extraction followed by multiple steps of chromatography and the pure proteins were further characterized biochemically. Peptide mixtures obtained after enzymatic digestion of the chicken antimicrobial proteins were analyzed using peptide mass fingerprinting and partial sequencing by tandem nanoelectrospray mass spectrometry and the proteins were identified as histones H1 and H2B. Chicken histone antimicrobial proteins were active against both Gram-positive and Gram-negative bacteria. The abundance of these proteins in the reproductive tissues and their broad-spectrum antimicrobial nature may indicate their defensive role against pathogens during the follicle development in the ovary and egg formation in the oviduct. The discovery of antimicrobial histones in chicken reproductive system provides further evidence that histones may play a role in innate immunity against microorganisms in a wide range of animal species. 相似文献
20.
The male genitalia of the rock hyrax (Procavia and Heterohyrax) are described. Features of the gross anatomy and histology of the testes and male accessory organs are presented, and comparison is made between the sexually active and sexually quiescent animal.
Microscopical observations have revealed the main area of storage of spermatozoa in this mammal and partly on these grounds, a new nomenclature for different parts of the reproductive system is proposed. Seasonal variations in male sexual activity in these mammals are also discussed, in addition to anatomical considerations. 相似文献
Microscopical observations have revealed the main area of storage of spermatozoa in this mammal and partly on these grounds, a new nomenclature for different parts of the reproductive system is proposed. Seasonal variations in male sexual activity in these mammals are also discussed, in addition to anatomical considerations. 相似文献