Characterization of CRH-Binding Protein (CRHBP) in Chickens: Molecular Cloning, Tissue Distribution and Investigation of Its Role as a Negative Feedback Regulator within the Hypothalamus-Pituitary-Adrenal Axis.

Corticotropin (ACTH) is a pituitary hormone playing important roles in stress response within the hypothalamus-pituitary-adrenal (HPA) axis. The biosynthesis and secretion of ACTH are controlled by multiple factors, including corticotropin-releasing hormone (CRH). As a key hypothalamus-derived regulator, CRH binds to corticotropin-releasing hormone receptor 1 (CRHR1) in the anterior pituitary gland to regulate ACTH synthesis and release. Thus, CRH-binding protein (CRHBP), which binds CRH with high affinity to inhibit CRH-induced ACTH secretion from pituitary cells, draws wide attention. In contrast to the extensive investigation of CRHBP in mammals and other lower vertebrates, the gene structure, tissue expression and physiological functions of CRHBP in birds remain largely unknown. In the present study, using chicken (c-) as our animal model, we examined the gene structure, tissue expression and functionality of CRHBP. Our results showed that: (1) cCRHBP cDNA encodes a 345 amino acid precursor, which shares high sequence identity with that of mammals, reptiles, frogs and fish; (2) cCRHBP is abundantly expressed in the brain (cerebrum and hypothalamus), pituitary and ovary; (3) cCRHBP inhibits the signaling of cCRHRs induced by cCRH, thus reducing the cCRH-induced ACTH secretion from cultured chick pituitary cells; (4) stress mediators (e.g., glucocorticoids) and stress significantly upregulate CRHBP mRNA expression in chickens, supporting its role as a negative feedback regulator in the HPA axis. The present study enriches our understanding of the conserved roles of CRHBP across vertebrates. In addition, chicken is an important poultry animal with multiple economic traits which are tightly controlled by the HPA axis. The characterization of the chicken CRHBP gene helps to reveal the molecular basis of the chicken HPA axis and is thus beneficial to the poultry industry.

Twelve natural estrogens in urines of swine and cattle: Concentration profiles and importance of eight less-studied.

Although four major natural estrogens (i.e., estrone (E1), 17ß-estradiol (E2), estriol (E3) and 17α-estradiol (αE2)) have been commonly found in livestock urine, this study reports the occurrence of eight other less-studied natural estrogens in urine of swine and cattle, i.e. 2-hydroxyestone (2OHE1), 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 16-epiestriol (16epiE3), 16α-hydroxyestrone (16αE1), 16-ketoestradiol (16ketoE2), and 17epiestriol (17epiE3). Results showed that each estrogen was found in at least one urine sample, and 6 of 8 the less-studied estrogens were present at frequencies of ≥90% in boars, ≥70% in sows, and ≥50% in dairy cattle. Five of eight the less-studied estrogens were present at frequencies of ≥33.3% in four beef cattle and one bull. On a concentration basis, the 8 less-studied natural estrogens represented 73.2%, 85.2%, 39.9%, 47.7%, 26.9%, 56.0% and 44.1% of total concentrations of the twelve natural estrogens when combining data from all animals. Similar results were observed based on estrogen equivalence, which indicated these newly detected eight less-studied natural estrogens were not negligible. This work is the first to figure out the importance of these less-studied natural estrogens in livestock urine, and their potential environmental risks associated with discharge of livestock wastewater should be urgently assessed in a holistic manner.

Impacts of silver nanoparticles on performance and microbial community and enzymatic activity of a sequencing batch reactor.

The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated under silver nanoparticles (Ag NPs) stress. Over 5 mg/L Ag NPs inhibited the COD and phosphorus removals, whereas the NH4+ removal kept stable during the whole operational period. The organic matter, nitrogen and phosphorus removal rates were obviously inhibited under Ag NPs stress, which showed similar varying trends with the corresponding microbial enzymatic activities. The change of Ag content in the activated sludge indicated that some Ag NPs were absorbed by the sludge. The presence of Ag NPs promoted the increase of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) of microorganism due to the microbial response to the Ag NPs toxicity, which could impact on the microbial morphology and physiological functions. The presence of Ag NPs could produce some evident changes in the microbial community.