The purpose of the present study was to examine the seminiferous epithelium cycle of Bombina orientalis using a light microscope. The cycle was divided into a total of 10 stages, according to the morphological characteristics of the cells. The spermatogenetic cells included primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatid and sperm. At stageⅠ, the primary spermatogonia was located closer to basal lamina of the seminiferous tubule without spermatocyst formations. Especially at the stage Ⅱ, the secondary spermatogonia were located in the spermatocyst. The primary and secondary spermatocytes were found from stages Ⅲ to Ⅵ. The secondary spermatocytes were smaller in size than the primary spermatocytes, but they had thicker nucleoplasm and smaller nuclei. The round-shaped, early sperm cells were formed in stage Ⅶ, and further divided at stage Ⅷ to have more concentrated nucleoplasm before division to matured sperm cells. At stage Ⅹ, the matured sperm cells emerged from the spermatocyst. Considering the above results, this study presented the special characteristics in the generation and type of sperm formation. The germ cell formation occurred in various stages, like the perspectives of Franca et al (1999), ultimately, providing taxonomically useful information.
This study investigated possible involvement of photoperiodic regulation in reproductive endocrine system of female olive flounder. To investigate the influence on brain-pituitary axis in endocrine system by regulating photoperiod, compared expression level of Kisspeptin and sbGnRH mRNA in brain and FSH-β, LH-β and GH mRNA in pituitary before and after spawning. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from Aug. 2013 to Jun. 2014. Continuous long photoperiod treatment from Aug. (post-spawning phase) was inhibited gonadal development of female olive flounder. In natural photoperiod group, the Kiss2 expression level a significant declined in Mar. (spawning period). And also, FSH-β, LH-β and GH mRNA expression levels were increasing at this period. However, in long photoperiod group, hypothalamic Kiss2, FSH-β, LH-β and GH mRNA expression levels did not show any significant fluctuation. These results suggest that expression of hypothalamic Kiss2, GtH and GH in the pituitary would change in response to photoperiod and their possible involvement of photoperiodic regulation in reproductive endocrine system of the BPG axis.
This study was conducted to determine the stress response [ethological (operculum movement number (OMN)), hematological (hematocrit and hemoglobin), biochemical (glucose, cortisol and glutamic oxaloacetic transaminase (GOT))] in red spotted grouper, Epinephelus akaara during exposure of different water temperature in winter season. This species (Total length, 18.56±0.34 cm) previously maintained in water temperature of 15°C were transferred to 15, 20 and 25°C. During experimental period (7 days), OMN, hematocrit (Ht), glucose and GOT values were significantly high in 15°C when compared to 20 and 25°C. Hemoglobin value was also increased at 15°C, but no significant differences. There was no differences in cortisol levels among the temperature groups. No fish mortality was observed during the experimental period. From these results, 15°C is likely more stressful to red spotted grouper than 20°C and 25°C. These observations confirm that red spotted grouper adapts better to temperatures between 20 and 25°C during the winter season.
We have launched an investigation for Embryonic Development, Larvae and Juvenile Morphology, of Buenos aires tetra in order to build basic data of Characidae and fish seeding production. We brought 50 couples of Characidae from Bizidduck aquarium in Yeosu-si, Jeollanamdo, from Korea on March of 2015. We put them in the tetragonal glass aquarium (50×50×30 cm). Breeding water temperature was 27.5~28.5°C (mean 28.0±0.05°C) and being maintained. The shape of fertilized egg was round shape, and it was adhesive demersal egg. The egg size was 0.63~0.91 mm (mean 0.74±0.07 mm, n=20). After getting fertilized egg, the developmental stage was gastrula stage, and embryo covered almost two-thirds of Yolk. Incubation was happened after 16 hours 13 minutes from gastrula stage, and the tail of juvenile came out first with tearing egg capsule. Immediately after the incubation, prelarvae had 3.78~3.88 mm length (mean 3.84±0.04 mm, n=5), and it had no mouth and anus yet. 34 days after hatching from the incubation, juvenile had 8.63~13.1 mm (mean 10.9±1.66 mm), and it had similar silver-colored body shape with its mother.
The gonadosomatic index (GSI), gonadal development and changes in hormones in plasma level of the indoor cultured grunt (Hapalogenys nitens) were investigated by histological study from August 2011 to October 2012. The GSI showed similar trends with gonad developmental stages during the culture periods. Changes in plasma level of estradiol-17β of female H. nitens reached the highest value before the spawning period, and seasonal changes in plasma level of estradiol-17β were similar in trends of oocyte developments and GSI changes. Testosterone levels of male H. nitens reached the highest value before and after the spent stage. Ovarian developmental stages of H. nitens could be classified into early growing stage, late growing stage, mature stage, ripe and spawning stage, recovery and resting stage. The testicular developmental stages could be divided into growing stage, mature stage, ripe and spent stage, and recovery and resting stage.
Connexin (Cx) is a complex which allows direct communication between neighboring cells via exchange of signaling molecules and eventually leads to functional harmony of cells in a tissue. The initial segment (IS) is an excurrent duct of male reproductive tract and expression of numerous genes in the IS are controlled by androgens and estrogens. The effects of these steroid hormones on gene expression in the IS during postnatal development have not extensively examined. The present research investigated expressional modulation of Cx isoforms in the IS by exogenous exposure to estrogen agonist, estradiol benzoate (EB), or androgen antagonist, flutamide (Flu), at weaning age. Two different doses of EB or Flu were subcutaneously administrated in 21-day old of male rats, and expressional changes of Cx isoforms in the adult IS were analyzed by quantitative real-time PCR. Treatment of a low-dose EB (0.015 μg/kg body weight) resulted in an increased expression of Cx31 gene and a decreased expression of Cx37 gene. A high-dose EB (1.5 μg/kg body weight) treatment caused an increase of Cx31 gene expression. Increased levels of Cx30.3 and Cx40 transcripts were observed with a low-dose Flu (500 μg/kg body weight) treatment. Treatment of high-dose Flu (50 mg/kg body weight) led to expressional increases of Cx30.3, 40, and 43 genes. Our previous and present findings suggest differential responsiveness on gene expression of Cx isoforms in the IS by androgens and estrogens at different postnatal ages.
Environmental conditions during early mammalian embryo development are critical and some adaptational phenomena are observed. However, the mechanisms underlying them remain largely masked. Previously, we reported that AQP5 expression is modified by the environmental condition without losing the developmental potency. In this study, AQP11 was examined instead. To compare expression pattern between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP11 by whole mount immunofluorescence. When the fertilized embryos were developed in the maternal tracts, the level of Aqp11 transcripts was decreased dramatically until 2-cell stage. Its level increased after 2-cell stage and peaked at 4-cell stage, but decreased again dramatically until morula stage. Its transcript level increased again at blastocyst stage. In contrast, the levels of Aqp11 transcript in embryos cultured in vitro were as follows. The patterns of expression were similar but the overall levels were low compared with those of embryos grown in the maternal tracts. AQP11 proteins were localized in submembrane cytoplasm of embryos collected from maternal reproductive tracts. The immune-reactive signals were detected in both trophectoderm and inner cell mass. However, its localization was altered in in vitro culture condition. It was localized mainly in the plasma membrane of the blastocysts contacting with external environment. The present study suggests that early stage embryo can develop successfully by themselves adapting to their environmental condition through modulation of the expression level and localization of specific genes like AQP11.