A Review on the Extraction, Bioactivity, and Application of Tea Polysaccharides.

Tea is a non-alcoholic drink containing various active ingredients, including tea polysaccharides (TPSs). TPSs have various biological activities, such as antioxidant, anti-tumor, hypoglycemic, and anti-cancer activities. However, TPSs have a complex composition, which significantly limits the extraction and isolation methods, thus limiting their application. This paper provides insight into the composition, methodological techniques for isolation and extraction of the components, biological activities, and functions of TPSs, as well as their application prospects.

Differential expression of three estrogen receptors mRNAs in tissues, growth development, embryogenesis and gametogenesis from large yellow croaker, Larimichthys crocea.

The biological activity of estrogens in target organs is mainly mediated by estrogen receptors (ERs). Herein, we addressed the isolation and expression analysis of three nuclear estrogen receptors, namely LcERα, LcERß1, and LcERß2 from Larimichthys crocea by means of SMART-RACE, qRT-PCR, and in situ hybridization. Results in different tissues showed that both LcERα and LcERß2 had the highest expression levels in female liver, followed by testis, but LcERß1 expression level was significantly higher in testis and ovary than in other tissues. Expression of LcERα and LcERß2 was significantly higher than LcERß1 in female liver, and LcERß2 was significantly higher than LcERα and LcERß1 in male liver. Moreover, we analyzed the expression of LcERs in gonad and liver at three different growth stages during the same breeding season. Significant up-regulated expression of LcERα and LcERß2 were found in female liver at 1000dph compared with at 270dph. The expression of LcERß2 was prominently higher in male liver than LcERα, LcERß1 and LcAR, while LcERß1 was lower than other receptors in male and female liver at all the three stages. In ovary, LcERα at 270dph was lower than at 635dph and 1000dph, but had no significant change in testis. The two LcERß subtypes and LcAR highly expressed in the early testis, and gradually decrease with the development of testis. In embryogenesis, a significant increase in the expression of LcERα and LcERß2 were observed after appearance of optic vesicles phase (11.8hpf). LcERß1 gradually decrease with the embryogenesis but increased dramatically at 1dph. Results of in situ hybridization showed that signals of LcERα and LcERß1 mRNA were mainly detected in Stage I-Stage IV oocytes, as well as in follicle cells around the Stage II-Stage IV and degenerated oocytes. Signals of LcERß2 were detected in the cytoplasm of Stage I and Stage II oocytes but not in the follicle cells of all oocytes stages. In parallel, LcERα and LcERß1 were detected in all cell types of spermatogenesis, but in terms of LcERß2, little or no signals were detected during spermatogenesis. Based on these results, we deduced that both LcERα and LcERß2 play a major role in mediating the physiological effects of estrogen in female liver, and LcERß2 maybe also play an important role in regulation of vitellogenesis in male liver. Differential expression of LcERs and LcAR imply their physiological functions during development and differentiation of gonad. The signals for LcERα and LcERß1 in follicle cells suggested that the follicle cell maybe an important site of estrogen action, by which estrogens exert influences on the maturation oocytes and ovulation. Furthermore, the steroid hormones produced by follicle cells may be related to the differential distributions among ER subtypes. Besides, we deduced that LcERα and LcERß1 rather than LcERß2 may play a major role in spermatogenesis of croaker. However, the differential expression of LcERß2 during gametogenesis also implicates its certain functions in mediating physiological process of estrogen action.

Molecular cloning, characterization, and gene expression of the androgen receptor in the large yellow croaker, Larimichthys crocea.

Androgens mediate a wide range of physiological responses and developmental processes in vertebrates, involving both reproductive and nonreproductive systems. The activity of androgens is mediated by the androgen receptor (AR), a member of the nuclear receptor superfamily. In this study, an AR gene was cloned from the large yellow croaker (Larimichthys crocea) for the first time. qRT-PCR revealed ubiquitous expression of AR in all adult tissues examined, with higher expression in the gonad and liver of both sexes and highest expression in the blastula stage of embryonic development. Using in situ hybridization, we detected positive signals of AR in the spermatogonium, spermatocyte, spermatid, and spermatozoon during spermatogenesis, in the cytoplasm of all oocytes during oogenesis and in the follicle cells of stage IV oocytes. Our findings support the important role that AR plays in gametogenesis, gonadal development, and the early stages of embryonic development.