Brevinin-2Eg

Four structurally related peptides with potent growth-inhibitory activity towards Escherichia coli were isolated from an extract of the stomach of the European green frog Rana esculenta, and were identified as members of the brevinin-2 family. Two peptides, termed brevinin-2Eg (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCK LS30GQC) and brevinin-2Eh (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCKL S30 KQC) have not been described previously. One peptide is identical to brevinin-2Ec, previously isolated from R. esculenta skin secretions, and one peptide is identical to brevinin-2Ef whose structure has been deduced from a cloned cDNA prepared from a R. esculenta skin cDNA library. The data demonstrate that certain peptides of the brevinin-2 family, like the magainins in the toad, Xenopus laevis, may play an important role in protecting the gastrointestinal tract of Ranid frogs against microbial invasion.

Objective: To study the expressions of differential proteins in the expressed prostatic secretion (EPS) of patients with III A chronic prostatitis and healthy men. Methods: We collected EPS samples from 35 patients with III A chronic prostatitis and 18 age-matched healthy men, and detected the differentially expressed proteins in EPS by MALDI-TOF/MS. Based on the data obtained, we conducted a statistical analysis on the mass-to-charge (m/z) ratios of different proteins and a retrieval analysis on the relevant proteins using the protein database. Results: In the comparative studies of the III A chronic prostatitis patients and healthy men, 5 proteins were detected as at least 2-fold differentially expressed, which were probably brevinin-2Eg, big endothelin-1, alpha-defensin 15, beta-defensin 134 and prostatic steroid-binding protein C2. The m/z ratios were significantly up-regulated in 3 372, 3 487, 425 and 5 325 Da proteins (P < 0.01) and down-regulated in 10631Da (P < 0.01). Conclusion: Proteins are differentially expressed in the EPS of III A chronic prostatitis patients and healthy men, and these proteins may be significantly correlated with the development and progression of III A chronic prostatitis.