Resumption of donor-origin spermatogenesis in senescent goldfish Carassius auratus (Linnaeus, 1758) following spermatogonial cell therapy

Stem cell research has come into prominence because of its applications in assisted reproductive technology and the treatment of deadly diseases. In teleost fishes, spermatogonial stem cells have been effectively used to produce surrogate gametes and progeny through germ cell transplantation technique. The present study is the first report of an innovative application of stem cell therapy in fish species for revitalising the reproductive competence of senescent individuals. Senescent male goldfish, Carassius auratus, approximately 10 years of age were procured from a fish-breeding farm and were reared locally in the lab for an additional two years. The senescence of the individuals was then evaluated and confirmed using histological analysis, gonadal index assessment, and germ-cell specific vasa gene expression. Analyses revealed absence of spermatogonial cells and other germ cells in the testes of the senescent fish (n = 5). Spermatogonial cells from sexually immature C. auratus male donor were isolated using discontinuous percoll gradients, labelled with the fluorescent dye PKH-26, and transplanted into the gonads of senescent C. auratus males through urogenital papilla. Six months after the transplant, spermatozoa were collected through applying gentle manual pressure on the abdomen and were observed under a microscope. All C. auratus males with the transplant had produced spermatozoa from the transplanted cells. This was confirmed by the retention of PKH-26 in the spermatozoa and diagnostic SSR locus. Gravid C. auratus females were artificially inseminated with the spermatozoa of those senescent males and natural spawning was allowed. As a result viable progeny were produced. These observation suggests that the reproductive competence of senescent male fishes can be revitalised through spermatogonial stem cell therapy to produce functional gametes.

Geographic distribution of Phalloceros Eigenmann, 1907 (Cyprinodontiformes, Poeciliidae) in the Ilha Grande Bay Hydrographic Region, Rio de Janeiro, Brazil

The diversity and geographic distribution of Phalloceros Eigenmann, 1907 in the Ilha Grande Bay Hydrographic Region, in southeastern Brazil, is investigated. Examination of 81 samples revealed the presence of 5 species in the region: Phalloceros anisophallos Lucinda, 2008, P. aspilos Lucinda, 2008, P. enneaktinos Lucinda, 2008, P. harpagos Lucinda, 2008, and P. tupinamba Lucinda, 2008. Phalloceros harpagos and P. tupinamba are recorded for the first time in the area. The geographic ranges of P. anisophallos and P. enneaktinos are expanded. The 5 species belong to 3 distinct morphologies of the female urogenital papilla. Species from these distinct morphological lineages may occur sympatrically, but species within the same lineage are always allopatric. A key for the identification of these species is provided.

Resumption of spermatogenesis in senescent goldfish Carassius auratus (Linnaeus, 1758) through spermatogonial cell therapy

In recent times, stem cell research has gained considerable prominence because of its applications in assisted reproductive technology and the treatment of deadly diseases. In teleost fishes, spermatogonial stem cells have been effectively used to produce progeny of difficult-to-breed fish species and/or commercially valuable species through the surrogacy technique. The present study is the first report of an innovative application of stem cell therapy in teleostean fish species for revitalising the reproductive competence of senescent individuals. Senescent male goldfish, Carassius auratus aged approximately 10 years were procured from an ornamental fish-breeding farm and were reared locally for an additional 2 years. The senescence of the fish was evaluated and confirmed using histological analysis, gonadal index assessment, and germ-cell specific vasa gene expression. Analyses revealed the absence of spermatogonial cells and other germ cells in the testes of the senescent fish (n = 5). Spermatogonial cells from a prepubertal C. auratus male donor were isolated using discontinuous percoll gradients, labelled with the fluorescent dye PKH-26, and transplanted into the gonads of senescent C. auratus males through the urogenital papilla. Six months after the therapy, spermatozoa from males were collected through applying gentle manual pressure on the abdomen and were observed under the microscope. All the senescent therapy-treated C. auratus males produced spermatozoa from the transplanted cells; this was confirmed by retention of PKH-26 in the spermatozoa and diagnostic SSR locus. The senescent males were crossed with gravid C. auratus females through artificial insemination and natural spawning, and viable progeny was produced. These observations suggest that the reproductive competence of senescent individuals of commercially valuable and/or endangered fish species can be revitalised and extended through spermatogonia stem cell therapy to produce functional gametes.

Morphology of the urogenital papilla and its component ducts in Astyanax altiparanae Garutti & Britski, 2000 (Characiformes: Characidae)

The histological description of the urogenital papilla is an important tool to comprehension of the reproductive mechanisms in fish, as well as a pre-requisite to germ cell transplantation in adult fish, besides to be a good biological indicator to environmental changes. Was performed the histological description of the urogenital papilla and its component ducts in the tetra Astyanax altiparanae. The genital and urinay ducts pass separately throughout most part of its extension, joining in a single duct before opening. In males this opening is asymmetric and seems to have double origin, being completely surrounded by striated muscle fibers, while in females it is symmetric and the muscle fibers does not surround it totally. Spermatic duct and oviduct undergo changes throughout their extension, mainly in the morphology of the surrounding epithelium. In the spermatic duct, squamous epithelial cells change to columnar and cuboid with possible secretory activity, close to testes. In the oviduct, anteriorly epithelial cells are also squamous, however, close to ovary there are lamellae composed by a pseudostratified epithelium with columnar and cuboid cells. The urinary duct is highly similar for both sexes presenting globoid cells, which description is known in mammals, however, rare in fish.

Callogobius winterbottomi, a new species of goby (Teleostei: Gobiidae) from the Western Indian Ocean

Callogobius winterbottomi new species is described from the 33.8 mm SL holotype and two paratypes (32.2 mm SL and 22.9 mm SL) from the Comoros, Western Indian Ocean. It is distinguished from all other known Callogobius species by the following combination of characters: sensory pores absent, 23–26 scales in lateral series, and sensory papillae pre-opercular row not continuous with transverse opercular row. One additional specimen of Callogobius winterbottomi was located from South Africa. A new standardized naming system for Callogobius sensory papillae rows is presented for identification and clarification of character states among Callogobius species. The new species is tentatively placed among what we term the “sclateri group”, a clade including C. sclateri (Steindachner) and three other species that exhibit a modified female urogenital papilla with lateral distal flaps and elongate ctenii on the caudal peduncle scales. Callogobius tutuilae (Jordan & Seale) is removed from synonymy with C. sclateri because it has partially united pelvic fins (vs separate) and the preopercular sensory papillae row is continuous with the transverse opercular row (vs separate).

A new species of Microlepidogaster (Siluriformes: Loricariidae: Hypoptopomatinae) from the upper rio Paraná basin, Brazil

Microlepidogaster longicolla, new species, is described from the rio São João of the upper rio Paraná basin near Brasília, in central Brazil. The new species differs from M. perforatus, the only other species in this genus, by having a continuous lateral line, median lateral plate series reaching, rather than falling short of, the end of the caudal peduncle, a shorter pectoral-fin spine (13.4-16.2 vs. 18.2-21.0% standard length), a smaller interorbital distance (38.9-43.1 vs. 47.7-53.3% head length), and more numerous dentary teeth (16-29 vs. 12-15), in addition to several osteological features. Microlepidogaster longicolla shows a remarkable suite of secondary sexually dimorphic characters, involving the presence of a conical urogenital papilla in males, the presence of a fleshy flap along the dorsal margin of first thickened pelvic-fin ray of males, longer pelvic fin in males, and a more strongly arched first pelvic-fin ray in females.