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Gonad Development (gonad + development)
Selected AbstractsGonad development and evidence of protogyny in the red-throat emperor on the Great Barrier ReefJOURNAL OF FISH BIOLOGY, Issue 2 2003K. Bean The gonad development in the red-throat emperor Lethrinus miniatus is described and the first detailed evidence for protogyny in this species provided. The identification of transitional individuals, bimodal sex-specific size-frequency distributions and female biased sex ratios suggest that L. miniatus is most likely a protogynous hermaphrodite. Transitional L. miniatus gonads were characterized by the concurrent degeneration of all oocytes and the proliferation of spermatocysts near the edge of the lamellae, an increase in blood vessels along strands of stromal tissue within the lamellae and the formation of multiple sperm sinuses. The sites of oocyte degeneration and proliferation of spermatocysts were spatially segregated. An increase in blood vessels along strands of stromal tissue within the lamellae of transitional phase gonads is likely to assist in the breakdown of oocytes and the proliferation of spermatocysts. Most mature resting females containing spermatocysts occurred within the transitional size-frequency distribution, suggesting that the presence of spermatocysts in these females may be an early sign of sex change. Oocytes within female gonads were interrupted by filamentous strands of stromal tissue within the lamellae. The testis contained a remanent ovarian lumen but no residual oocytes. Three characteristics of transitional L. miniatus gonads were found to be unusual and described for few other species of coral reef fishes. These included the absence of oocytes within testes, increased numbers of blood vessels, and the presence of strands of stromal tissue within the lamellae. [source] China rose (Hibiscus rosasinensis) petals: a potent natural carotenoid source for goldfish (Carassius auratus L.)AQUACULTURE RESEARCH, Issue 11 2007Archana Sinha Abstract Goldfish (Carassius auratus) are in demand in world markets due to their attractive golden colour. Carotenoids are the primary source of colour in the skin of fish. To optimize the colour in captivity, fish must obtain an adequate level of carotenoids in their feed. With this objective, four natural colour enhancers were tested. A common batch of feed was divided into five equal portions and colour ingredients, spirulina (D-S), china rose petals (D-C), marigold petals (D-M) and Lactobacil, a commercial probiotic (D-L), were added at 5 mg kg,1 to four portions of feed; one portion (D-O) was kept as a control without any additive. A feeding trial was conducted for 8 weeks. Each 70 L aquarium was stocked with 10 fish (average weight 1.6 g) and feed was given at 5% of the body weight. Growth rate, survival, biochemical composition and pigmentation in the skin of fish were measured. Histological studies of gonads were also conducted. Growth of fish in different treatments was significantly different. There was no difference in the proximate composition of the fish at the start of the experiment but after 8 weeks of feeding, fish fed the diet supplemented with china rose petals had a lower moisture content (70.48%) and higher protein (17.7%) and lipid (5.25%) levels than the group fed the control diet. Pigmentation was the highest (4.01 ,g g,1) in D-C, followed by D-M (3.16 ,g g,1), D-S (2.92 ,g g,1) and D-L (2.84 ,g g,1) and the lowest (0.24 ,g g,1) in D-O. Gonad development of fish fed with the D-C diet was better compared with the gonads of control (D-O) fish, followed by D-M-, D-L- and D-S-fed fish. Gonads of fish, fed D-C, showed well-marked changes in the testis where a large number of seminiferous tubules bound together by means of a thin layer of connective tissue were observed. These tubules were highly convoluted and were separated from each other by thin connective tissue stroma. The intra space contained connective tissue, blood capillaries and interstitial cells. The spermatogonia could be seen as a large spherical cell containing a large central nucleus with a distinct nucleolus. The study shows that the china rose (Hibiscus rosasinensis) petal is a potent natural carotenoid source for goldfish to enhance its colour and also accelerate gonadal development. [source] Novel markers of early ovarian pre-granulosa cells are expressed in an Sry -like patternDEVELOPMENTAL DYNAMICS, Issue 4 2009Hyunjoo J. Lee Abstract Mammalian gonad differentiation involves sexually dimorphic cell-fate decisions within the bipotential gonadal primordia. Testis differentiation is initiated by a center-to-poles wave of Sry expression that induces supporting cell precursors (SCPs) to become Sertoli rather than granulosa cells. The initiation of ovary differentiation is less well understood. We identified two novel SCP markers, 1700106J16Rik and Sprr2d, whose expression is ovary-biased during early gonad development, and altered in Wnt4, Sf1, Wt1, and Fog2 mutant gonads. In XX and XY gonads, both genes were up-regulated at ,E11 in a center-to-poles wave, and then rapidly down-regulated in XY gonads in a center-to-poles wave, which is reminiscent of Sry expression in XY gonads. Our data suggest that 1700106J16Rik and Sprr2d may have important roles in early gonad development, and are consistent with the hypothesis that ovarian SCP differentiation occurs in a center-to-poles wave with similar timing to that of testicular SCP differentiation. Developmental Dynamics 238:812,825, 2009. © 2009 Wiley-Liss, Inc. [source] Reproduction in three species of rainbowfish (Melanotaeniidae) from rainforest streams in northern Queensland, AustraliaECOLOGY OF FRESHWATER FISH, Issue 2 2001B. J. Pusey Abstract , The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis, which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history., [source] Effects of the synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2005Bradley J. Park Abstract Estrogenic contaminants are known to disrupt growth and development in amphibians. Field-based research is needed to elucidate their potential impacts on wild populations. Hatch success, larval growth and development rates, and gonad development were examined in native amphibians exposed to low ng/L concentrations of 17,-efhinylestradiol (EE2) in a whole-lake addition experiment at the Experimental Lakes Area, northwestern Ontario, Canada. Egg masses were reared in situ in the EE2-amended lake and in two reference lakes in 2001 and 2002. Hatching success was reduced significantly in green frogs (Rana clamitans) but not in mink frogs (Rana septentrionalis) exposed to EE2. Ethinylestradiol had no consistent effect on mass or development stage of hatchlings in the early larval stages of the caging study. Ethinylestradiol had no effect on sex ratios of either species in situ, and no intersex gonads were observed in exposed or reference green frog tadpoles or in reference mink frog tadpoles. However, 5.6% (total n = 18) and 12.5% (total n = 56) of EE2-exposed mink frog tadpoles were intersex in the 2001 and 2002 caging studies, respectively. Wild mink frog tadpoles also were examined, and EE2 had no effect on sex ratios. No intersex gonads were observed in reference lake tadpoles or in tadpoles from the experimental lake prior to EE2 additions; however, 2.4, 0, and 28.6% of wild EE2-exposed first-year tadpoles had intersex gonads (2001, 2002, and 2003, respectively). These results indicate that exposure to EE2 in the wild and in situ at concentrations comparable to those detected in effluents and, occasionally, in surface waters can impact gonad development and hatch success in native amphibians. [source] Timing of exposure to a pulp and paper effluent influences the manifestation of reproductive effects in rainbow troutENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2002Michael R. Van den Heuvel Abstract Rainbow trout were exposed to a secondary treated, thermomechanical/bleached kraft pulp and paper effluent in 12,000-L, flow-through exposure tanks at an environmental research facility located at a pulp and paper mill in Kawerau, New Zealand. Trout (age, 2+ years) were obtained from a local hatchery and exposed either to upstream river water or a nominal concentration of 12% (v/v) effluent diluted in upstream river water. Three treatment groups were used: Effluent exposure that started approximately three months before gonadal growth (eight-month total exposure), effluent exposure that started approximately halfway through gonadal development (two-month total exposure), and trout exposed to reference water alone for the total duration of the experiment. Trout were sacrificed just before spawning; exposure, growth, and reproductive endpoints were assessed during and at the termination of the experiment. Reduction in growth was observed in both sexes in the eight-month treatment group relative to the river water reference treatment group. No differences were observed in condition factor or liver size in either treatment. Females in the eightmonth exposure group also had significantly lower ovary weight. The two-month exposure group showed no differences from the reference group in growth or somatic indices. Estradiol and testosterone were reduced in blood samples taken from the eight-month exposure group by four months into the experiment as compared to the reference treatment. Steroid and vitellogenin levels in individual female trout from this treatment were significantly correlated with gonadosomatic indices (GSI) measured at the termination of the experiment. The GSI was not correlated strongly or consistently with pregnenolone, nor were any treatment-related pregnenolone differences observed, indicating that the steroid hormone reductions likely were not related to cholesterol side-chain cleavage. Male trout showed significant induction of vitellogenin and lower 11-ketotestosterone during the experiment (only the eight-month group was examined), but this did not result in any significant differences in testes development. Thus, this study has shown an impact of pulp mill effluent exposure on the reproductive physiology of female trout that appeared to be hormonally mediated. Furthermore, the effect could only be manifest when the exposure was initiated before the start of gonad development. [source] Internal brooding of clonal propagules by a sea anemone, Anthopleura sp.INVERTEBRATE BIOLOGY, Issue 4 2003Naoko Isomura Abstract. We investigated the seasonal prevalence of reproductive activities and of the development of brooded propagules in an intertidal sea anemone, Anthopleura sp., on the rocky shore of Mutsu Bay, in northern Japan. A monthly examination of anemones, by dissection and histological techniques, revealed no sign of gonad development, but did reveal that they produce and internally brood propagules throughout the year. Release of propagules was observed in the field. This anemone population appears to be entirely asexual and agametic, and may persist solely through clonal propagation. [source] Estimating the timing of growth rings in Atlantic cod otoliths using stable oxygen isotopesJOURNAL OF FISH BIOLOGY, Issue 3 2006H. Hřie A technique involving micro-scale sampling of otolith carbonate and analyses of stable oxygen isotope composition was used to relate the zone appearance of the otolith to the seasonal temperature cycle. Otolith opacity could then be related to the timing of zone formation. Otoliths from two groups of Atlantic cod Gadus morhua held under known temperature conditions over a period of 4 and 6 years were examined. The otolith translucency followed the same pattern as the estimated temperature (from otolith ,18O values) in the yearly increments three and four, meaning that the translucent zones were deposited at the seasonal highest temperature in late summer and early autumn. The relative light intensities of otolith yearly increments five and six of older fish (deposited in the same years), however, were not significantly correlated to the estimated temperatures since increased otolith translucency also occurred at low temperatures. This might have been caused by stress in connection with gonad development or starvation during the spawning period. The results showed that this method of coupling otolith opacity and stable oxygen isotope composition can be used to estimate the timing of zone formations in otoliths. [source] The biology of Roule's goby in the Kvarner area, northern Adriatic SeaJOURNAL OF FISH BIOLOGY, Issue 4 2001M. Kova Roule's goby Gobius roulei in the Kvarner area of the northern Adriatic Sea attained , 87.5 mm LT and an age of 7 years. In both sexes gonad development began in their second year. All males were mature by 3 years, and females by 4 years. Fecundity was related to LT and varied between 1200 and 8000 eggs. The breeding season lasted from April to August. Nests were built under empty shells of Pitaria chione or stones. Roule's goby was a predator and picker, feeding mostly on mobile benthic fauna, including bivalves, gastropods, polychaets, pagurids, mysids, gammarids and fishes. Larger specimens ate mainly macrofauna, while smaller specimens ate both meiofauna and macrofauna. [source] The matricellular protein SPARC is internalized in Sertoli, Leydig, and germ cells during testis differentiationMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2006Megan J. Wilson Abstract The gene encoding the matricellular protein secreted protein, acidic and rich in cysteine (SPARC) was identified in a screen for genes expressed sex-specifically during mouse gonad development, as being strongly upregulated in the male gonad from very early in testis development. We present here a detailed analysis of SPARC gene and protein expression during testis development, from 11.5 to 15.5 days post coitum (dpc). Section in situ hybridization analysis revealed that SPARC mRNA is expressed by the Sertoli cells in the testis cords and the fetal Leydig cells, found within the interstitial space between the testis cords. Immunodetection with anti-SPARC antibody showed that the protein was located inside the testis cords, within the cytoplasm of Sertoli and germ cells. In the interstitium, SPARC was present intracellularly within the Leydig cells. The internalization of SPARC in Sertoli, Leydig, and germ cells suggests that it plays an intracellular regulatory role in these cell types during fetal testis development. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Expression of Serpinb6 serpins in germ and somatic cells of mouse gonads,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2006Yves Charron Abstract The serpin superfamily of serine protease inhibitors is implicated in the regulation of numerous physiological processes. In mice, Spi3/Serpinb6 has a broad tissue distribution. We have investigated the expression of Serpinb6 family members in embryonic and adult gonads. In male and female mice, Spi3/Serpinb6 and NK13/Serpinb6b were expressed in developing gonads and in both somatic and germ cells of adult gonads. By contrast, gonadal expression of Spi3C/Serpinb6c was sexually dimorphic and restricted to male germ cells and female somatic cells. These observations raise the question of the possible role(s) of the Serpinb6 family members in gonad development, gametogenesis, and/or fertilization. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source] Evaluation of practical diets containing different protein levels on gonad development of female redclaw crayfish Cherax quadricarinatusAQUACULTURE NUTRITION, Issue 4 2009H. RODRÍGUEZ-GONZÁLEZ Abstract The effect of five experimental diets with different crude protein content (220, 270, 330, 390 and 450 g kg,1) on gonad development of female Cherax quadricarinatus was tested under laboratory conditions. After 70 days, a significant linear relationship indicated that higher concentrations of protein and carbohydrates in the hepatopancreas were produced as the dietary crude protein increased (P < 0.05). There were significant responses of the gonadosomatic index, hepatosomatic index, biochemical composition of the gonad (protein, lipids, carbohydrates and energy) and frequency of secondary vitellogenic oocytes to dietary protein level, as indicated by significant fits of the quadratic equation to the observed experimental data. The optimal response of the criteria parameters corresponded to levels of crude protein in the range 284,355 g kg,1. Overall, 330 g kg,1 crude protein with a protein : energy ratio of 15.6 mg kJ,1 was considered the most adequate concentration of dietary protein for gonad development and biochemical composition in female redclaw crayfish. [source] Quantification of vitellin/vitellogenin-like proteins in the oyster Crassostrea corteziensis (Hertlein 1951) as a tool to predict the degree of gonad maturityAQUACULTURE RESEARCH, Issue 6 2009Fabiola G. Arcos Abstract The oyster's reproductive process is poorly documented, especially in terms of a quantitative approach. In recent years, investigations with this species have been directed at determining important reproductive factors. Within this scope, techniques that allow standardized and accurate quantitative estimations of gonad development have become of primary importance. In this study, the histological characteristics and the levels of vitellin/vitellogenin-like proteins (Vn/Vtg) from ovaries of the Mexican Pacific ,pleasure' oyster Crassostrea corteziensis (Hertlein 1951) were analysed during different stages of gonad maturation using quantitative histological techniques and an enzyme-linked immunosorbent assay. This was performed in order to evaluate a possible quantitative tool to predict the degrees of gonad maturity and to analyse the biological implications of the findings relative not only to broodstock conditioning but also to natural populations. Using this information, we expect to be able to undertake further research on different reproductive aspects of this oyster species, including, among others, evaluation of the response in Vn/Vtg concentrations to different diets and environmental conditions during laboratory conditioning. [source] Genetic characterization and gonad development of artificially produced interspecific hybrids of the abalones, Haliotis discus discus Reeve, Haliotis gigantea Gmelin and Haliotis madaka HabeAQUACULTURE RESEARCH, Issue 5 2008Faruq Ahmed Abstract Hybridization among abalone species has been suggested as a possible means to increase their growth rates for aquaculture. As a first step to test the usefulness of the hybrids of Japanese abalone species (Haliotis discus discus, Haliotis gigantea and Haliotis madaka) for aquaculture, we characterized the genetic background and gonad development of hybrids that were produced by artificial insemination. The hybrid status of the resulting offspring was confirmed by assaying 14 allozymes and by RFLP analysis of the 16s rRNA and cytochrome oxidase I (COI) regions of mtDNA using 13 restriction enzymes. Histological examination of the gonads of the hybrids was conducted in comparison with those of the parental species. Cross-breeding among the three species was conducted successfully in all combinations although with lower fertilization rates (means of 1.3,60.8%) than the parental species (34.3,90%). Crosses between H. discus discus and H. madaka had higher fertilization rates (22.4,60.8%) than those involving H. gigantea (1.3,19.9%). The hybrids were ascertained by the presence of both parental genotypes at the LDH-A, ME-A, MDH-A and GPI loci. The maternal origin of the hybrid mtDNA was confirmed by digestion with DdeI, TaqI, HpaII of the COI region. No polymorphism was observed in the 16S rRNA region. The hybrids had gonadal development and maturity stages similar to the parental species up to fully mature oocytes and sperm. They spawned upon stimulation and produced viable offspring with high fertilization rates and successful development to the juvenile stage in back- and homologous hybrid crosses. [source] Annual sex hormonal profiles, gonad development and age determination of the Mekong giant catfish (Pangasianodon gigas, Chevey)AQUACULTURE RESEARCH, Issue 15 2003A Manosroi Abstract Annual sex hormonal profiles, gonad development and age determination of 18 (13,14 kg body weight) and three (145,226 kg body weight) Mekong giant catfish (MGC) (Pangasianodon gigas, Chevey) reared in earthen ponds in Chiang Mai and from the Mekong River in Chiang Rai, Thailand, respectively, were investigated. The hormonal profiles were determined from blood samples of the fish by electrochemiluminescence immunoassay during May to August in 2000. The highest testosterone levels of 0.06 ng mL,1 in both sexes and the highest oestradiol of 47.8 and 14.23 pg mL,1 in females and males, respectively, were observed in May. The gonadosomatic index was found to be 0.07 for males and 0.38 for females from ponds in comparison with 2.27 for males and 8.29 for females from the Mekong River. Higher development stages of spermatocytes and oocytes of the cultured fish in May than in February and November were demonstrated. No mature germ cells were obtained from either the males or females, indicating no sexual maturity. The average age of fish was determined from the annual rings of the cross-section of the pectoral fins by a stereomicroscope. The average age of fish in earthen pond determined from the annual ring was 8 years, which agreed with the actual culture records, while those from the Mekong River were 21 years. This information will be beneficial for the breeding programmes and conservation of the MGC. [source] | |||||||||||||