Effects of Bisphenol A and Its Substitute, Bisphenol F, on the Gut Microbiota in Mice.

Objective: The aim of this study was to assess the impact of bisphenol A (BPA) and its substitute, bisphenol F (BPF), on the colonic fecal community structure and function of mice. Methods: We exposed 6-8-week-old male C57BL/6 mice to 5 mg/(kg∙day) and 50 µg/(kg∙day) of BPA or BPF for 14 days. Fecal samples from the colon were analyzed using 16S rRNA sequencing. Results: Gut microbiome community richness and diversity, species composition, and function were significantly altered in mice exposed to BPA or BPF. This change was characterized by elevated levels of Ruminococcaceae UCG-010 and Oscillibacter and decreased levels of Prevotella 9 and Streptococcus. Additionally, pathways related to carbohydrate and amino acid metabolism showed substantial enrichment. Conclusion: Mice exposed to different BP analogs exhibited distinct gut bacterial community richness, composition, and related metabolic pathways. Considering the essential role of gut bacteria in maintaining intestinal homeostasis, our study highlights the intestinal toxicity of BPs in vertebrates.

Highly efficient expression of human extracellular superoxide dismutase (rhEcSOD) with ultraviolet-B-induced damage-resistance activity in transgenic silkworm cocoons.

Extracellular superoxide dismutase (EcSOD) protects tissues from oxidative stress, and thus is considered as a therapeutic agent for many diseases such as atherosclerosis, hypertension, and cancer. However, cost-effective production of bioactive recombinant human EcSOD (rhEcSOD) remains a challenge. Herein, we developed an efficient strategy for producing active rhEcSOD by transgenic silkworms. rhEcSOD was successfully synthesized as homodimers and homotetramers in the middle silk gland and spun into the cocoons with a concentration of 9.48 ± 0.21 mg/g. Purification of rhEcSOD from the cocoons could be conveniently achieved with a purity of 99.50% and a yield of 3.5 ± 0.5 mg/g. Additionally, N-glycosylation at the only site of N89 in rhEcSOD with 10 types were identified. The purified rhEcSOD gained the potent enzymatic activity of 4 162 ± 293 U/mg after Cu/Zn ions incorporation. More importantly, rhEcSOD was capable of penetrating and accumulating in the nuclei of cells to maintain cell morphology and attenuate ultraviolet B-induced cell apoptosis by eliminating reactive oxygen species and inhibiting the C-Jun N-terminal kinase signaling pathway. These results demonstrated that the transgenic silkworm could successfully produce rhEcSOD with enzymatic and biological activities for biomedical applications.

The interaction of MC3R and MC4R with MRAP2a in rainbow trout (Oncorhynchus mykiss).

Melanocortin 3 and 4 receptors are two important neural G protein-coupled receptors that regulate energy homeostasis in vertebrates. Melanocortin receptor accessory protein 2 (MRAP2) is also involved in the regulation of food intake and body weight as a variable regulator of melanocortin receptors. Rainbow trout (Oncorhynchus mykiss) is a valuable cold-water fish cultured worldwide. In the rainbow trout model, we cloned and identified mrap2a, a paralog of mrap2. Rainbow trout mrap2a consisted of a 690 bp ORF and was expected to encode a putative protein of 229 amino acids. The qPCR results showed that rainbow trout mrap2a was expressed at high levels in brain tissue similar to mc3r and mc4r. In addition, co-immunoprecipitation verified that MRAP2a interacts with MC3R and MC4R in vitro and that MRAP2a is involved in and regulates the constitutive activity and signaling of MC3R and MC4R. MRAP2a reduced constitutive and agonist-stimulated cAMP levels of MC3R; furthermore, MRAP2a increased constitutive ERK1/2 activation but reduced ligand-induced stimulation at high levels of expression. For MC4R, MRAP2a showed decreased cAMP basal activity but increased agonist-stimulated cAMP signaling and increased ACTH ligand sensitivity. However, MRAP2a failed to affect MC4R constitutive activity and agonist-induced ERK1/2 signaling. Undoubtedly, our study will have great significance for revealing the conserved role of MC4R and MC3R signaling in teleost fish, especially in cold-water fish growth and energy homeostasis.

[The effect of ethanol on sexual function of males and its mechanism].

Though an adequate volume of ethanol relieves nervousness and enhances sexual desire,long term and excessive intake of ethanol can induce sexual dysfunction. The reasons that ethanol results in sexual dysfunction are as follows: ethanol inhibits the hypothalamo-pituitary-testes axis and decreases serum testosterone level. The decline of smooth muscle, choline acetyltransferase and nitric oxide synthase in the penis may be responsible for it.