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1.
Gwo JC  Chiu JY  Lin CY  Su Y  Yu SL 《Tissue & cell》2005,37(2):109-115
The mature spermatozoa of two Taiwan protandrous hermaphrodite Sparidae Acanthopagrus berda and Acanthopagrus australis are investigated and compared with those of other two Sparidae (Lagodon rhomboids and Archosargus probatocephus) from the Western hemisphere. Ultrastructurally the spermatozoon of these four species has a spherical, homogeneously electron-dense nucleus with an axial nuclear fossa. The midpiece contains one to four spherical mitochondria and encircles the basal body of the flagellum. The mature spermatozoa of the four species are of the primitive or ect-aquasperm form and conform to the teleostean type I spermatozoon with the flagellar axis inserts perpendicular and medial to the nuclear fossa. Variation in the depths of the nuclear fossa and mitochondria number is substantial in these four Sparidae species. This study provide useful systematic characters to the existing knowledge of comparative spermatology of Sparidae.  相似文献   

2.
The ultrastructure of spermatogenesis and of the spermatozoon of Acanthopagrus schlegeli (Sparidae) are described. The testis is of the unrestricted type. Germ cells are surrounded by cyst cells. Spermiogenesis involves conspicuous modifications such as intracellular movements (diplosome and mitochondria migration, nuclear rotation, and depression) and structural changes (chromatin condensation, shape of mitochondria, and loss of cytoplasm). The mature spermatozoon has a spherical nucleus with a deep, axial nuclear fossa, and an unusual notch, shaped like a bow tie. The short midpiece contains four spherical mitochondria and encircles the basal body of the flagellum. It is concluded that the A. schlegeli spermatozoon is of a primitive type, but that it is characterized by a unique feature which may provide a useful systematic character. © 1993 Wiley-Liss, Inc.  相似文献   

3.
Mature spermatozoa of two perciform teleost fishes, Paraupeneus spilurus (Mullidae) and Siganus fuscescens (Siganidae) from Taiwan were examined using transmission and scanning electron microscopy. Despite the fact that spermatozoa of both species are of the primitive type, the results of the present study highlight the potential application of spermatozoal morphology in studies of fish phylogenetic relationships. To our knowledge, the flattened nucleus observed in P. spilurus spermatozoa is reported for the first time. Several features common to Sigandae spermatozoa-the unusual almost parallel situation of the centrioles, the arrangement of mitochondria and the near absence of shallow nuclear fossa-are significantly different from other common teleost sperm types. These unique features may be synapomorphies for the Siganidae and Mullidae and evidently contribute to the study of phylogenetic relationships in teleosts.  相似文献   

4.
The ultrastructure of spermiogenic stages and spermatozoa of representatives of two gymnotiform families, Gymnotus cf. anguillaris (Gymnotidae) and Brachyhypopomus cf. pinnicaudatus (Hypopomidae) were studied. Spermiogenesis of both species is characterized by lateral development of the flagellum and formation of a nuclear fossa. Some differences were found between these species, such as whether (B. cf. pinnicaudatus) or not (G. cf. anguillaris) nuclear rotation occurs, permanence of the cytoplasmic channel, and type and localization of the nuclear fossa. In the G. cf. anguillaris spermatozoon the nucleus is spherical with highly condensed chromatin. The nuclear fossa is shallow and lateral and is associated with the centriolar complex through stabilizing fibrils. The midpiece is short, with many vesicles, a cytoplasmic channel, and elongate mitochondria. In the B. cf. pinnicaudatus spermatozoon the ovoid nucleus is elongated lateral and posterior to the centriolar complex, and has highly condensed chromatin. The eccentric nuclear fossa is of the moderate type, and contains the entire centriolar complex. The midpiece is long, with numerous vesicles, elongate mitochondria, and no cytoplasmic channel. In both species the flagella are laterally disposed in relation to the nucleus and comprise of the classical 9+2 axoneme. Most of the characteristics found in the spermatozoa of these two species of Gymnotiformes are shared with species of Characiformes, whereas only a few are also found in Siluriformes. This suggests that Gymnotiformes and Characiformes may be more closely related than previously proposed.  相似文献   

5.
Love CC 《Theriogenology》2011,76(3):547-557
Sperm quality has an important role in determining fertility. Although there have been numerous studies to document the relationship between sperm quality and fertility, the methods of determining this association and conclusions vary. In the present study, computer-assisted sperm analysis (CASA) was used for evaluation of sperm motility, and differential interference contrast (DIC) microscopy was used for evaluating sperm morphologic features of breeding stallions. Fertility was measured using three endpoints: seasonal pregnancy rate (PR), percent pregnant/cycle (PC), and percent pregnant/first cycle (FCP). Increased total sperm motility (P = 0.08) and progressive path velocity (P = 0.06) tended to be associated with higher PR, whereas percent coiled tails (P = 0.02) was associated with a lower PR. Sperm motility variables associated with an increase in PC and FCP included total, progressive, and rapid sperm motility, and increased path and progressive velocity. Percent pregnant/first cycle was the only fertility measure able to discriminate among high, average, and low fertility groups, based on total and progressive sperm motility. Percent normal sperm was the only morphology variable associated with an increased PC and FCP, whereas increased levels of most sperm morphologic abnormalities (including abnormal and detached heads, proximal and distal droplets, general midpiece abnormality, and coiled tails) were associated with a decline in PC and FCP. Sperm quality variables most highly correlated with fertility included percent total sperm motility (PR, r = 0.37, P < 0.05; PC, r = 0.59, P < 0.05; and FCP, r = 0.64, P < 0.05), and percent morphologically normal sperm (PC, r = 0.42, P < 0.05; and FCP, r = 0.39, P < 0.05).  相似文献   

6.
During spermiogenesis, the spermatids of the pimelodid species Pimelodus maculatus and Pseudoplatystoma fasciatum show a central flagellum development, no rotation of the nucleus, and no nuclear fossa formation, in contrast to all previously described spermatids of Teleostei. These characteristics are interpreted as belonging to a new type of spermiogenesis, named here type III, which is peculiar to the family Pimelodidae. In P. maculatus and P. fasciatum, spermatozoa possess a spherical head and no acrosome; their nucleus contains highly condensed, homogeneous chromatin with small electron-lucent areas; and a nuclear fossa is not present. The centriolar complex lies close to the nucleus. The midpiece is small, has no true cytoplasmic channel, and contains many elongate and interconnected vesicles. Several spherical to oblong mitochondria are located around the centriolar complex. The flagellum displays the classical axoneme (9+2) and no lateral fins. Only minor differences were observed among the pimelodid species and genera. Otherwise, spermiogenesis and spermatozoa in the two species of Pimelodidae studied exhibit many characteristics that are not found in other siluriform families, mainly the type III spermiogenesis.  相似文献   

7.
The morphological characteristics of Synbranchus marmoratus female germ cells in various development stages were described in details; then measurements of ovarian follicle diameters were taken from primary and secondary growth as during these development stages the oocyte size varied considerably along the fish growth. The results were correlated to total fish length, using the individuals division in six size classes. It was possible to group oocytes by stages according to histological characteristics but not according to morphometric diameter, as there was a wide variation in diameter in each stage and overlap between different maturation stages. These data make available new information on the reproductive biology of Synbranchidae.  相似文献   

8.
Summary The extracutaneous pigment cell system of the plaice (Pleuronectes platessa L.) was examined by light and electron microscopy in selected regions, including two cutaneous regions for comparison. The extracutaneous pigmentation consists of guanocytes and melanocytes with differing distributions within the body. The eyeless side lacks melanocytes. The pigment cells are differentiated as very flat elements with long processes. They display an affinity for loose connective tissue at boundary layers such as the peritoneal epithelium, organ capsules or blood vessels, to which they are parallelly arranged at a very constant distance. In some locations guanocytes are intimately associated with melanocytes forming reduced chromatophore units. Extracutaneous pigment cells are poor in mitochondria, endoplasmic reticulum, microfilaments, caveolae intracellulares, ribosomes and glycogen granules, all of which are more abundant in cutaneous pigment cells and pigment cells of the eye. In extracutaneous guanocytes the crystals are loosely arranged parallel to the cell surface, in cutaneous guanocytes perpendicular. Cells with rod-like vesicular cisternae are described as guanoblasts. No single pigment cell was found exhibiting different types of pigment granules. The varying colors of extracutaneous pigmentation arise from varying combinations of guanocytes and melanocytes in addition to the color of the tissue itself.In partial fulfillment for the degree of Doctor of Medicine under the direction of Prof. Dr. Dr. H.-R. Duncker (Giessen)  相似文献   

9.
In the present study spermiogenesis was investigated in Cetopsis coecutiens (Cetopsidae), and Bunocephalus amazonicus (Aspredinidae), while spermatozoa ultrastructure was investigated in C. coecutiens, B. amazonicus, and Nematogenys inermis (Nematogenyidae). Aspredinidae and Cetopsidae share a spermatogenesis of the semicystic type, and a particular type of spermiogenesis process not reported in any fish group. In the three species analyzed, spermatozoa are biflagellate with flagella having the classical axoneme formulae (9 + 2). The analysis of thirteen characters showed the presence of eight characters shared by Cetopsidae and Aspredinidae, and six characters shared by Cetopsidae and Nematogenyidae, which may suggest that these three families may be more related than actually hypothesized, comprising a very primitive siluriform lineage originated after Diplomystidae.  相似文献   

10.
Summary The ductus epididymidis of the tammar is lined by an epithelium composed of principal, mitochondria-rich, apical and basal cells, and intraepithelial leucocytes. The epithelium is structurally differentiated into 6 zones referred to as the initial segment, middle segment (3 subdivisions) and terminal segment (2 subdivisions). The occurrence of the initial, middle and terminal segments corresponds quite closely to the anatomical differentiation of the epididymis into a head, body and tail.The initial segment epithelium in the tammar is lower and has shorter and more slender stereocilia than in other mammals which have been described. Otherwise, the structure of the epithelium has similar characteristics in the tammar to that described in other mammals.Spermatozoa begin to develop the capacity for motility within the initial segment, but only show structural signs of maturation in the middle segment. The sperm head rotates through 90 degrees in the proximal subdivision of the middle segment. The cytoplasmic droplet is detached and spermatozoa develop the capacity for motility in the middle subdivision of the middle segment. The cytoplasmic droplets are phagocytosed by the epididymal epithelium of the middle segment. Sperm storage appears to be the main function of the terminal segment.  相似文献   

11.
Spawning behaviour of the blue sprat Spratelloides gracilis was observed at shallow reefs of Kuchierabu‐jima Island, southern Japan. The fish carried out promiscuous spawning behaviour on substrata covered with algal mats mainly in the intertidal region of a shallow inlet. The spawning events occurred only at predawn (20–50 min before sunrise) and daily for c . 25 days from mid‐June to mid‐July.  相似文献   

12.
运用电子显微镜技术和细胞化学方法对秀丽虾精子进行了形态和超微结构研究,结是要发现,秀丽白虾精荚中有形似外翻状的成熟精子,精子主体部凸面伸长约6-7um的单个棘突,主体部基部为非电子致密的均匀核,核膜呈半解体状态,帽状体中有约20根放射状纤丝和大量内含电子致密基质的膜泡,棘突和帽状构成顶体复合体,成熟精子中未发现中心体。  相似文献   

13.
14.
A total of 148 specimens of Mitsukurina owstoni were examined for morphology, distribution, stomach contents, and reproductive condition. Sixty-nine males (81.7–208.5 cm in total length, TL) and 56 females (92.8–196.1 cm TL) were collected with bottom gillnets along a steep slope of the Tokyo Submarine Canyon (100–350 m depth) from May 1995 to October 1996. In addition, data were obtained from 23 specimens of M. owstoni collected from Sagami Bay, Suruga Bay, and the Enshu-nada Sea from 1972 to 2001. Japanese catch records already published (from 1898) plus those in the present study were from the Pacific coast of Japan, from Choshi to the Kii Peninsula. The main fishing season for M. owstoni by bottom gillnet fishing in the Tokyo Submarine Canyon was October to April, at depths of 200–245 m. No specimens examined were sexually mature, including the largest male (208.5 cm TL) and female (196.1 cm TL) recorded. Of 110 stomachs from specimens from the Tokyo Submarine Canyon, 32 (29.1%) were empty. The remainder variously included teleost fishes, squids, decapods, isopods, digested food, and human refuse. Teleost fishes (Macrouridae sp. and Stomiidae spp.), an isopod (Cymothoidae), and decapods (Pasiphaea sinensis and Sergia sp.) were the only identifiable prey, the indication being that teleosts (all size ranges) were of primary importance as prey for M. owstoni.  相似文献   

15.
Summary The pattern of sperm retention and migration in the vagino-cervical region of rabbit was studied by means of scanning electron microscopy. The following phenomena were observed: 1) Spermatozoa located in the vagina and at the orifice of the ectocervix are usually distributed diffusely. They appear to be resting on the epithelial surface; many are structurally abnormal or decapitated. 2) The great majority of spermatozoa, however, seems to be anchored or retained in narrow epithelial channels with their heads in close file formations. This phenomenon was observed particularly in the fornix vaginae as late as 24 h post coitum. 3) A great number of spermatozoa invading the cervix evidently migrates in groups along the mucosal surface. Their heads are oriented toward the uterus and contact the epithelial cells. Spermatozoa that migrate beyond the cervico-uterine junction are distributed in the same manner. 4) Spermatozoa colonizing the cervical crypts appear to be attached via the anterior margins of their heads to the epithelial cells or to the tips of kinocilia. Their tails project into the crypt lumen. It is suggested that mainly three factors may be responsible for these phenomena: (i) the fact that only motile spermatozoa overcome the vagino-cervical barrier; (ii) the tendency of spermatozoa to move along the mucosa in close vicinity to the epithelial cells; and (iii) the inability to recognize mechanical barriers on the migration route (e.g., cervical crypts) and to overcome them quickly. This may be one of many possible causes leading to sperm retention in the vagino-cervical region.Supported by a grant from the Deutsche Forschungsgemeinschaft  相似文献   

16.
Six cohorts of the silver-stripe round herring Spratelloides gracilis , a fast-growing and short-lived tropical clupeid, were collected as juveniles and then as adults during austral summers from November to February in 1998–1999 and 1999–2000, using light traps in the Dampier Archipelago, Western Australia. Otolith analysis allowed backcalculation of size and growth rate at age to examine the relative influences of selective mortality and water temperature on early growth. Negative size-selective mortality and growth-selective mortality between the juvenile and the adult stages was found only in the cohort that was the smallest and slowest growing in the period immediately following hatching. Selective mortality preferentially removed members of this cohort that were smaller from age 0 to 15 days, and slower growing from 0 to 10 days, resulting in an elevation of size at age to, or even above, that of cohorts that had not undergone this process. Size and growth rate at 5 day age intervals in the first 20 days after hatching differed among cohorts within and between summers and were strongly and positively correlated ( r 2= 0·61–0·83) with water temperature.  相似文献   

17.
Nemerteans possess serially arranged gonads that lie between the midgut pouches. In both sexes the gonads are lined with an epithelium. During maturity, they gain contact to the exterior by a ciliated duct, which is generally assumed to be a derivative of the gonad. Gonad lining and sperm ultrastructure are little known in heteronemerteans, a group of nemerteans belonging to the Anopla, one of the two large nemertean subgroups. Reproduction biology in heteronemertean Lineus viridis allows predicting a modified sperm type, so-called introsperm for this taxon. Nothing is known on the fate of the testes at the end of the reproductive period of this perennial species. In order to test the predictions and to broaden the data base, males of L. viridis were collected at different times of the year. Histological and ultrastructural data show that the gonad wall is lined with different aciliated endothelial cells and germ cells, while the gonoduct is formed by densely ciliated cells. The testes are completely filled with sperm cells during maturity; there is no hint at ongoing spermiogenesis at this time. The sperm consists of head, midpiece and tail. Externally, head and midpiece cannot be discriminated. The acrosome is cup-shaped and lies anterior to the nucleus which contains 6–8 lateral ridges. Three long mitochondria mark the midpiece. They line the posterior section of the nucleus and extend up to the level of the ciliary basal structures. The sperm morphology corroborates the predictions derived from the mode of reproduction. At the end of the reproductive period the male gonads change cellular composition, while the gonoduct degenerates. Provided that both sexes show the same growth rate, male offspring acquire sexual maturity earlier than female offspring, since L. viridis males are always smaller than the females. In contrast to the males, females keep their gonads and gonoducts during most time of the year. Since large males were never found within the studied population, these data indicate that L. viridis might be a consecutive hermaphrodite.  相似文献   

18.
Gwo JC  Kuo MC  Chiu JY  Cheng HY 《Tissue & cell》2004,36(2):141-147
Transmission and scanning electron microscopy were used to investigate the ultrastructure of spermatozoa in two Sparinae species Pagrus major and Rhabdosargus sarba. Ultrastructurally, the spermatozoa of P. major and R. sarba both consist of a spherical, homogeneously electron-dense nucleus with a deep axial nuclear fossa, and an unusual notch, in the nuclear region. The midpiece contains two spherical mitochondria in R. sarba and one in P. major. The comparison of spermatozoal ultrastructure of these two species of Sparidae shows that they closely resemble one another and suggests that they are closely related. Variation in the geometry and dimensions of the mitochondrion and nucleus is substantial in these two Sparidae species. It is concluded that the spermatozoa of both species are of primitive type, and they are distinguished by several unique features which may provide useful systematic characteristics.  相似文献   

19.
The aim of this study was to elaborate cryopreservation methods for ex situ conservation of European catfish. The success of sperm cryopreservation was evaluated by post-thaw sperm motility and velocity, percentage of live spermatozoa and fertility (hatching rates) using frozen/thawed sperm. The best hatching rates of 82-86% were obtained with sperm stored for 5 h before freezing in immobilizing solution and frozen with Me2SO in concentrations of 8, 10, and 12%, or with a mixture of 5% Me2SO and 5% propandiole. These results did not significantly differ from the fresh sperm control sample. The percentage of live spermatozoa in frozen/thawed sperm did not correlate with hatching rate or motility of spermatozoa, but was negatively correlated with velocity of spermatozoa (r=-0.47, P=0.05). The percentage motility in frozen/thawed sperm ranged from 8 to 62%, when sperm was stored in immobilizing solution 5h before freezing. The average value in the fresh sperm (control) was 96%. The frozen/thawed sperm motility rate significantly correlated with the hatching rate (r=0.76, P=0.0002), but not with the percentage of live spermatozoa (r=0.16, P=0.52) or the sperm velocity (r=0.07, P=0.79). The velocity of frozen/thawed spermatozoa ranged from 37 to 85 microm/s, whereby methanol concentrations of 7.5 and 10% resulted in highest velocities. Freezing sperm volumes of 1-4 ml did not affect the quality of frozen/thawed sperm.  相似文献   

20.
The eyes of the sandlance, Limnichthyes fasciatus (Creediidae, Teleostei) move independently and possess a refractive cornea, a convexiclivate fovea and a non-spherical lens giving rise to a wide separation of the nodal point from the axis of rotation of the eye much like that of a chameleon. To investigate this apparent convergence of the visual optics in these phylogenetically disparate species, we examine feeding behaviour and accommodation in the sandlance with special reference to the possibility that sandlances use accommodation as a depth cue to judge strike length. Frame-by-frame analysis of over 2000 strikes show a 100% success rate. Explosive strikes are completed in 50 ms over prey distances of four body lengths. Close-up video confirms that successful strikes can be initiated monocularly (both normally and after monocular occlusion) showing that binocular cues are not necessary to judge the length of a strike. Additional means of judging prey distance may also be derived from parallax information generated by rotation of the eye as suggested for chameleons. Using photorefraction on anaesthetised sandlances, accommodative changes were induced with acetylcholine and found to range between 120 D and 180 D at a speed of 600–720 D s−1. The large range of accommodation (25% of the total power) is also thought to be mediated by corneal accommodation where the contraction of a unique cornealis muscle acts to change the corneal curvatures. Accepted: 8 December 1999  相似文献   

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