The spermatozoa and eggs of the cardinal fish (original) (raw)
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Characterization of spermatozoa and eggs of the rabbitfish
Journal of Fish Biology, 1999
The spermatozoon of Siganus rivulatus is symmetrical in its longitudinal axis, has no acrosome, an almost spherical nucleus, a small mid-piece with six mitochondria, centrioles arranged at an acute angle to each other, no nuclear fossa, and a flagellum without fins. Sperm motility is reversibly inhibited in the seminal plasma, and in electrolyte and non-electrolyte solutions of 100 mosmol kg 1 and activated by an increase in osmotic pressure. The sperm motility parameters remain constant for 5 min after activation, then motility starts to decrease and stops 25-30 min after activation. Osmolalities between 600 and 1100 mosmol kg 1 and a pH between 7·5 and 9·0 do not affect the sperm motility parameters. The eggs of S. rivulatus contain several large central lipid droplets composed of neutral lipids and glycolipids. Glycogen granules and sialoglycoproteins are dispersed between the lipid droplets. The protein yolk, consisting of neutral and slightly basic proteins is located peripherally. The cortical alveoli containing neutral polysaccharids are located in the outermost regions in close vicinity to the oolemma. The chorion is two-layered and has no specialized surface structures. 1999 The Fisheries Society of the British Isles
Animal Reproduction Science, 2013
The present study on wild caught Atlantic cod Gadus morhua provides a detailed description of the spermatozoa ultrastructure. The spermatozoa of G. morhua are composed of a head (nucleus) with no acrosome, a midpiece and a single flagellum. The total length is 67.69 ± 6.33 m with a lanceolate sperm head that is 2.34 ± 0.26 m long and 1.32 ± 0.26 m wide. The nucleus presents homogeneous condensation of chromatin with few lacunae of decondensed chromatin. The nuclear fossa penetrates over three third of the nuclear axis and is tubiform. The axoneme is composed of a typical 9 + 2 microtubular doublet structure and is enclosed by the plasma membrane. Central microtubules are absent from the proximal portion of the anterior end of nuclear notch and a distal centriole complex is perpendicular to the axoneme. A group of mitochondria and vesicles is present in the midpiece. The ultrastructure of the Gadidae G. morhua spermatozoon differs from the structures described earlier for other Gadiformes. The unique features may be synapomorphic for marine Gadidae, and may contribute to the study of phylogenetic relationships in teleost fishes, and be a reference for future studies on spermatozoon quality and morphology in fish.
African Journal of Biotechnology, 2012
The current study was designed to study the ultrastructure of the spermatogenic stages of the protandrous hermaphrodite sparid Diplodus cervinus cervinus. Although, it is a useful tool to enhance understanding of germ cells differentiation in this economic species, none of the available references paid attention to the studied species. The testis of the studied specie is tubular in shape and the germ cells are arranged in cysts or clusters within the seminiferous lobules. Spermatogenesis occurs in several places along the length of each lobule and induced by the action of the somatic steroidogenic secretory cells which are known as Leydig cells. Such cells contained four main morphological structural characteristics a vesicular nucleus, ovoid and elongated mitochondria with tubular cristae, a number of smooth endoplasmic reticula, and a considerable amount lipid droplets in the cytoplasm. Spermatogenic cyst displays round shaped cells with large nuclei containing clumps of heterogenic dense chromatin and reduced cytoplasm known as primary spermatogonia. They undergo a series of mitotic divisions to reach the secondary spermatogonia stage; such cells irreversibly divide meiotically to form primary and secondary spermatocytes.
Structure and composition of the fish egg chorion
Journal of Ultrastructure and Molecular Structure Research, 1988
The mature egg of fishes is surrounded by an acellular coat conventionally called the chorion. In Carassius auratus three main layers can be recognized at the electron microscopic level, and we have termed them chl, ch2, and ch3 starting from the outer side to the inner side close to the egg plasma membrane. Isolated chorion from mature ovarian and ovulated eggs can be obtained by homogenization and further purification techniques. We analyzed these preparations on sodium dodecyl sulfate-palyacrylamide gel electrophoresis, and at least 20 polypeptide chains were reproducibly observed. The solubilization conditions were tested by means of various agents under reducing and nonreducing conditions. The present report focuses on the temporal and spatial pathway of chorion formation during oocyte growth, and we report the solubilization and partial characterization of protein and glycoprotein components of purified chorions.
IOSR Journal of Pharmacy and Biological Sciences, 2014
Transmission and scanning electron microscopy were used to investigate the ultrastructure of spermatogenesis of the Sparid fish Rhabdosargus sarba. The testis is lobular in shape and spermatogensis is of unrestricted type. Spermatogonia occur isolated or in clusters within the seminiferous lobules. The germ cells are found in cysts formed by sertoli cell processes. Cells within cysts are found in the same developmental stage. Spermiogenesis is characterized by chromatin condensation, movement of the centrioles, flagellum development, nuclear rotation, nuclear indentation and nuclear fossa formation, reduction of the cytoplasm and differentiation of the flagellar complex. Ultrastructurally the spermatozoa of R. sarb belonges, like that of other sparid fish, to the teleosean "type 1" spermatozoan with the flagellum axis perpendicular to the nuclear fossa. It has an ovoidal head, a short, cylindrically shaped midpiece and a long tail region. The nucleus reveals a deep invagination (nuclear fossa) in which the centrriolar complex is located, and a satellite nuclear noch shaped like a bell. The centriolar complex lies inside the nuclear fossa and is composed of a proximal and a distal centriole. The two centerioles are perpendicular to each other. The distal centriole is traversed by a conspicuous basal plate in its base. At the neck of the flagellum the necklace is observed. A nuclear noch is located above the proximal centeriol. The short midpiece houses two spherical mitochondria. The flagellum is inserted medio-laterally into the head, contains the conventional 9+2 axoneme.
Marine fish spermatozoa: racing ephemeral swimmers
Reproduction, 2008
Abbreviations : SW = sea water, SM = swimming medium, SF = seminal fluid, BF = beat frequency, WA = wave amplitude, OP = osmotic pressure, ATP = adenosine triphosphate, ADP = adenosine diphosphate, P Cr = phosphocreatine.
Tissue and Cell, 2004
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.
Histology and histopathology
Scanning and transmission electron microscopy were used to investigate the fine structure of the sperm of the sparid fish Sparus aurata L. The mature spermatozoon of gilthead sea bream belongs, like that of the other sparid fish, to a "type I" as defined by Mattei (1970). It has a spherical head which lacks an acrosome, a short, irregularly-shaped midpiece and a long cylindrical tail. The nucleus reveals a deep invagination (nuclear fossa) in which the centriolar complex is located. The two centrioles are approximately perpendicular to each other and show a conventional "9+0" pattern. The proximal centriole is associated with a cross-striated cylindrical body lying inside a peculiar satellite nuclear notch which appears as a narrow invagination of the nuclear fossa. The distal centriole is attached to the nuclear envelope by means of a lateral plate and radial fibres made of an electron-dense material. The short midpiece houses one mitochondrion. The flagellum is...
Structural analysis of fertilization in the fish Brycon orbignyanus
Zygote, 2009
SummaryIn the present work, we analyzed the structure of oocytes and fertilized eggs of the piracanjuba fish (Brycon orbignyanus) under light and scanning electron microscopy. After inducing spawning, samples were collected at the moment of oocyte extrusion, when oocytes and semen were mixed (time 0), as well as at 10, 20 and 30 s after mixing, every minute up to 10 min, and then at 15 and 20 min. The oocytes are spherical, translucent and greenish with a mean diameter of 1.3 ± 0.11 mm. During the extrusion, cytoplasmic movement was observed in eggs towards the micropyle, characterizing the animal pole. At the moment of fertilization, the cortical cytoplasm showed a higher concentration of cortical alveoli at the animal pole than at the vegetal pole. The cortical alveoli breakdown promoted the elevation of the chorion with a consequent increase in egg diameter (1.95 ± 0.08 mm). The penetration of the spermatozoon promotes the formation of a fertilization cone of spherical external s...