Studies On Androgen Receptor And C-fos Regulation In Oogenesis Of Reticulitermes Aculabialis

Reticulitermes aculabialis (Isoptera: Rhinotermitidae) is one of the major building pests in China. The present paper revealed the microstructure of castes differentiation, spermatogenesis, sex hormone and the immediate early-gene c-fos regulation of oogenesis in nymph and worker by histology , cytology and immuneohistochmistry methods for probing into molecular regulation . The main results are as follow:1. Five stages in spermatogenesis of Reticulitermes aculabialis were distinguished and described according to the changes of the shape of cells. The five stages were spermatogonia, primary speramtocyte, second spermatocyte, spermatid and sperm. The mature sperm was vented from copulating. Termite spermatogenesis is similar to other insects. That is, the nucleolus becomes smaller and smaller, the cohesion of the cytoplasm becomes stronger and stronger. The isogenous cluster was found in spermatogenesis.2. Worker is the largeste caste in termite colony, whose gonad development is restrained. Usually, worker can turn into reproductives according the demand of the termite colony. Our research showed that the oogenesis of worker was similar to the level of last nymph. Yolk forming stage didn't exist in worker. This was the reason of no mature ovum in worker. But worker has a potential ability to turn into reproductives because of its complete differentiation stage and the growth stage in oogenesis. The spermatogenesis in worker included spermatogonia, primary speramtocyte, second spermatocyte and spermatid, but mature sperm was not found. The results revealed the facts of gonad development restraining of worker in histological level.3. Androgen receptor (AR) is important in the regulation of the gonad development, such as oogenesis and spermatogenesis of vertebrates. In order to understand the role of AR during the oogenesis of termite, method of immunocytochemical localization was employed to investigate the location of AR at different stages of female reproductives and workers during the oogenesis of Reticulitermes aculabialis. The results indicated that the receptors of androgen existed in all the ovaries of the last instar nymph, the swarming females and the workers. Androgen receptor was located in the cytoplasm of oocytes at differentiation stage and growth stage in last instar female nymphs and swarming females, but it was located in the follicular cells at the yolk forming stage in swarming females. In the ovary of the workers, AR was distributed in the cytoplasm of oocytes at differentiation stage and growth stage. Yolk forming stage didn't exist in workers. AR played an important role in oogenesis of termites. These results provide a new proof of AR participating in the regulation of oogenesis development.4. The immediate early-gene c-fos palys an important role in cell multiplication and differentiation. It has been confirmed that c-fos is a factor in germ cell multiplication and differentiation. Method of immunocytochemical localization was employed to investigate whether the c-fos was expressed in oogenesis of termite. The result revealed that the immunopositive c-fos was showed in the nucleus of oocytes and follicular cells at differentiation stage and growth stage in last instar nymph and swarming female. It revealed that c-fos and oogenesis was colosely-related. This indicates that c-fos plays an important role in the adjustment of oogenesis.In conclusion, the gonad of woker and reproductives were compared, the gonad development of the worker was found to be restrained. The oogenesis of workers was similar to the level of last nymph.The spermatogenesis included spermatogonia, primary speramtocyte, second spermatocyte and spermatid, but mature sperm was not found. Worker can turn into reproductives according the demand of the termite colony. AR and c-fos played an important role in oogenesis of termites, indicating that AR and c-fos participating in the regulation of oogenesis and castes differentiation.