Abstract:The ultrastructural features of the sperm were studied in the hermaphroditic teleost Satanoperca jurupari HECKEL, 1840 from Amazon River. Spermatocytes, spermatids and sperm develop in the testicular cysts among the different oocyte stages. Different stages of early spermatocyte development, mainly the ones with synaptonemal complexes were often observed. The mature spermatozoa belong to the introsperm type, with a short head (~ 3 µm long and 1.3 µm wide) without acrosome, short midpiece (~ 1.2 µm long and 1.8… Show more
“…According to Jamieson (1991) it has occurred at least six times in fishes. Recently, Matos et al (2002) described biflagellar tails in a cichlid fish, Satanoperca jurupari, not observed in testes of a larger group of species from the same family studied by Fishelson (2003a, b). According to these authors the sperm flagella in Satanoperca are separated, each bearing lateral cytoplasmic extensions (wings).…”
Section: Discussionmentioning
confidence: 92%
“…Studies by Franzen (1970), Mattei (1971Mattei ( , 1988, Billard (1986), Lashnsteiner and Patzner (1990), and Fishelson (2003a, b) revealed a diversified structure of the sperm and their tails (flagella) in various fish families. All these studies demonstrated that in most teleosts, as in other vertebrates, the sperm possess a single flagella, while only a few families, e.g., batrachids, bagrids, myctophids, gobiesocids, and more recently cichlids, contain species that have been found with biflagellar sperm (Mattei 1988;Matos et al 2002). The published studies enable comparison of the various components of the developing gametocytes, and consequent evolutionary considerations (Mattei 1988(Mattei , 1991.…”
The testes in all 16 of the studied cardinal fish species are shown to be bilobed, with spermatogonia dispersed throughout the gametogenic epithelium of the seminiferous tubules. Each testicular lobe is covered luminally by an epithelium consisting of primary germ cells and Sertoli cells. At maturation the seminiferous tubules reach around 0.6-2.3 mm in length. They number from 60 in the smallest species to over 300 in the largest one, increasing both in dimension and number with increase in length of the male, and are species-specific. The highest number of spermatogonia is found at the apical ends of the tubules. During maturation extensions of Sertoli cells surround single or small groups of B-spermatogonia, forming the spermatocysts, the final dimensions of which reflect the final number of contained spermatozoids. Back-calculations of serial sections reveal that within the spermatocysts the spermatogonia undergo eight generations of mitotic divisions before the first and second meiotic divisions and formation of spermatids. The largest mature spermatocysts in large species attain around 180 microm in diameter, a volume of 25 mm(3), and contain around 8,200 spermatids. The total volume of sperm in the mature spermatocysts leaves enough space for the discarded cytoplasm and developing flagella. The bursting cysts liberate the ripe sperm and maturing spermatids, into the tubule lumen and spermduct, with the spermatids often still connected by cytoplasm bridges. The sperm, with one or two flagella, features round or oval heads and a cytoplasmic collar bearing a few mitochondria. The percentage of biflagellate or monoflagellate sperm differs in proportion in males of different lengths and in different species. Differences in spermatogenesis of small and larger species of cardinal fish are discussed.
“…According to Jamieson (1991) it has occurred at least six times in fishes. Recently, Matos et al (2002) described biflagellar tails in a cichlid fish, Satanoperca jurupari, not observed in testes of a larger group of species from the same family studied by Fishelson (2003a, b). According to these authors the sperm flagella in Satanoperca are separated, each bearing lateral cytoplasmic extensions (wings).…”
Section: Discussionmentioning
confidence: 92%
“…Studies by Franzen (1970), Mattei (1971Mattei ( , 1988, Billard (1986), Lashnsteiner and Patzner (1990), and Fishelson (2003a, b) revealed a diversified structure of the sperm and their tails (flagella) in various fish families. All these studies demonstrated that in most teleosts, as in other vertebrates, the sperm possess a single flagella, while only a few families, e.g., batrachids, bagrids, myctophids, gobiesocids, and more recently cichlids, contain species that have been found with biflagellar sperm (Mattei 1988;Matos et al 2002). The published studies enable comparison of the various components of the developing gametocytes, and consequent evolutionary considerations (Mattei 1988(Mattei , 1991.…”
The testes in all 16 of the studied cardinal fish species are shown to be bilobed, with spermatogonia dispersed throughout the gametogenic epithelium of the seminiferous tubules. Each testicular lobe is covered luminally by an epithelium consisting of primary germ cells and Sertoli cells. At maturation the seminiferous tubules reach around 0.6-2.3 mm in length. They number from 60 in the smallest species to over 300 in the largest one, increasing both in dimension and number with increase in length of the male, and are species-specific. The highest number of spermatogonia is found at the apical ends of the tubules. During maturation extensions of Sertoli cells surround single or small groups of B-spermatogonia, forming the spermatocysts, the final dimensions of which reflect the final number of contained spermatozoids. Back-calculations of serial sections reveal that within the spermatocysts the spermatogonia undergo eight generations of mitotic divisions before the first and second meiotic divisions and formation of spermatids. The largest mature spermatocysts in large species attain around 180 microm in diameter, a volume of 25 mm(3), and contain around 8,200 spermatids. The total volume of sperm in the mature spermatocysts leaves enough space for the discarded cytoplasm and developing flagella. The bursting cysts liberate the ripe sperm and maturing spermatids, into the tubule lumen and spermduct, with the spermatids often still connected by cytoplasm bridges. The sperm, with one or two flagella, features round or oval heads and a cytoplasmic collar bearing a few mitochondria. The percentage of biflagellate or monoflagellate sperm differs in proportion in males of different lengths and in different species. Differences in spermatogenesis of small and larger species of cardinal fish are discussed.
“…In addition, light microscopy and TEM revealed that they are biflagellate. To our knowledge, the only cichlid with biflagellate sperm described so far is Satanoperca jurupari, a self-fertilizing hermaphrodite with introsperm-type spermatozoa (Matos et al 2002). The existence of two flagella is even more exceptional among cichlids.…”
Rey Vázquez, G., Da Cuña, R.H., Meijide, F.J., and Guerrero, G.A. 2012. Spermatogenesis and changes in testicular structure during the reproductive cycle in Cichlasoma dimerus (Teleostei, Perciformes). -Acta Zoologica (Stockholm) 93: 338-350.The present study aimed at analyzing spermatogenesis and the changes occurring in the testis throughout the reproductive cycle in the South American perciform fish Cichlasoma dimerus. Testes were studied using light and electron microscopy techniques. This species has an unrestricted lobular testis composed of two compartments: germinal, containing Sertoli and germ cells, exhibiting a cystic mode of spermatogenesis; and interstitial, composed of Leydig cells and connective tissue elements. Spermatozoa belong to the anacrosomal type I aquasperm and possess two flagella, this being the first report of an externally fertilizing cichlid exhibiting biflagellate sperm. Under laboratory conditions, C. dimerus proved to be a multiple spawner throughout the year, with a season of higher reproductive activity extending from September to March, during which fish spawned on average every 29.4 days. Changes in the germinal epithelium and the germ cell stages present allowed the description of five reproductive classes: regressed, early, mid-, and late maturation, and regression. During the high reproductive season, each cycle went through the first four classes. The regressed class overlapped with the late maturation class, because sperm was being released while spermatogonia were proliferating. The regression class occurred solely in sexually inactive males during the period of low reproductive activity.
“…Often, the plasma membrane also forms one or two fin-like ridges along the fish sperm flagellar tail, which are oriented along the horizontal axis defined by the central microtubules [34][35][36][37]. The ribbon shape instead of the usual cylindrical shape of the flagellum makes it brighter when observed by dark-field microscopy and allows to better visualization and recording of wave shapes [6].…”
A fish spermatozoon has a minimalist structure: head, mid-piece and flagellum with the active inner core, called "axoneme". The axoneme represents a cylindrical scaffold of microtubular doublets arranged around a pair of single microtubules and assorted along the entire length with the dynein-ATPase motors. The mechanisms of wave generation along the flagellum becomes possible due to sliding of microtubules relative to each other and their propagation is a result of a balance between mechanical constraints and intra-flagellar biochemical actors that generate force.How fish sperm flagella mechanics adapt to external constraints, such as vicinity of surfaces or viscosity, during the very short period of motility? By use of high-speed video microscopy, stroboscopic system, modelisation and simulation approaches, we show that fish sperm flagella respond to physical and chemical signals from environment in a very brief period of time.This review chapter presents a brief description of the biological and biochemical features that characterize fish spermatozoa. Then it describes the biophysical aspects of flagellar movement covering various topics involved in fish sperm motility and offering a compilation of the recent knowledge acquired on different physical properties, such as wave propagation, energetics, hydrodynamics, temperature, viscosity, axonemal microtubules dynamics, among other aspects.
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