title: Physicochemical and biological characterizations of Pxt peptides from amphibian (Xenopus tropicalis) skin.
abstract: Pxt peptides (Pxt-1 through Pxt-12) have been isolated from amphibian, Xenopus tropicalis Pxt-related peptides (Pxt-2, Pxt-5, Pxt-12, reverse Pxt-2, reverse Pxt-5 and reverse Pxt-12) with significant foaming properties were further characterized. In the physicochemical experiments, all Pxt-related peptides formed significant amphiphilic α-helices in 50% 2,2,2-trifluoroethanol by circular dichroism measurements. Among Pxt-related peptides, both Pxt-5 and reverse Pxt-5 were the most effective in reducing their surface tensions. Moreover, Pxt-2, Pxt-5 and reverse Pxt-5 produced constant surface tensions above their critical association concentrations, suggesting the micelle-like assemblies. In the biological experiments, Pxt-5 possessed the most potent hemolytic activity, while reverse Pxt-5 exhibited the most remarkable gene expression of interleukin 8 and heme oxygenase 1 and the most potent cytotoxicity in HaCaT cells. In contrast, Pxt-12 and reverse Pxt-12 were much weaker in antimicrobial assays for Gram-negative bacteria, Gram-positive bacteria and yeasts, as well as in hemolytic, cell viability and cytotoxicity assays in HaCaT cells. All Pxt-related peptides exhibited about 20-50% of the total cellular histamine release at 10(-5) M, as well as mastoparan and melittin in mast cells. Real-time polymerase chain reaction analysis confirmed the gene expressions of Pxt-5 in testis and Pxt-12 in muscle, in addition to skin, while Pxt-2 was only in skin.
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan; yasushi.shigeri@aist.go.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shigeri
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan;
authors.forename: Masanori
authors.initials: M
authors.lastname: Horie
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan;
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan;
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Hagihara
authors.affiliation: Research Institute for Chemical Process Technology, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan;
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imura
authors.affiliation: Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 Japan; and.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Inagaki
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Haramoto
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Asashima
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development*; D002460:Cell Line; D003603:Cytotoxins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008297:Male; D009928:Organ Specificity; D017433:Protein Structure, Secondary; D014981:Xenopus; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D023181:Antimicrobial Cationic Peptides; D003603:Cytotoxins; D029867:Xenopus Proteins
keywords: Xenopus tropicalis; amphiphilic α-helical peptides; antimicrobial peptide; expression; surface tension