P-55 Rapidithrix属海洋細菌が生産する新規抗菌性ポリケチドペプチドariakemicin類の構造(ポスター発表の部)

概要

論文の詳細を見る
In this symposium we will summarize our 6-year activity on construction of marine microbe library and present part of our results on the exploration of new bioactive molecules from our collection. The 6-year project entitled "Construction of a Genetic Resource Library of Unidentified Microorganisms", initiated by New Energy Industrial Technology Development Organization (Ministry of International Trade and Industry jurisdiction), aimed at establishing domestic sound research foundation to promote better utilization of microbial function in industry. As one of the contractors for this project, Marine Biotechnology Institute Co., Ltd. (Kamaishi, Japan) has focused on collecting microbes from marine environments. During 2002-2008, we have conducted more than 25 samplings along the coast of Japan Islands and around Micronesian Islands such as Yap, Palau, and Pohnpei, and constructed a comprehensive library of more than 25 thousands marine-derived microbes, with nearly one fifth being new at species level based on the 16S rDNA sequence. The library is mainly composed of proteobacteria belonging to Alpha- and Gamma- subclasses and Bacteroidetes group bacteria, but importantly includes many species from Phyla Planktomycetes, Verrucomicrobia, Chloroflexi, and Gemmatimonadates, which in the past the isolation have only been sparsely reported. Additionally, more than 500 of new fungi, based on the 28S rDNA sequence, were identified in our collection. The collected microorganisms were systematically cultivated to obtain their fermentation extracts and stocked in a 96-deep-well format to distribute as unique biomedical screening sources to our 20 collaborators from universities and companies. This extract library is also screened with our in-house assay settings to evaluate its biomedical potential. One of the promising strains that we encountered during the in-house antibacterial screening is HC35, which belongs to a recently proposed genus Rapidithrix within the Phylum Bacteroidetes. The strain was isolated with an E.coli-streaked seawater-agar plate method from subsurface silts of the muddy land alongside the Ariake Inland Sea, southwest Japan. Fermentation of strain HC35 in modified Marine Broth 2216 and bioassay-guided fractionation resulted in the isolation of novel antibiotics, ariakemicins A and B. The ariakemicins, a pair of positional isomers with regard to a double bond, are unusual linear polyketide-peptides marked by a oxazole ring, two highly unsaturated polyketide chains, and a terminal isovanilloylbutyl group, the latter two of which are connected through two enamide linkages. Antimicrobial testing against 7 strains composed of Gram-positive and Gram-negative bacteria and a yeast Candida albicans revealed that this chromatographically inseparable mixture was effective at killing Gram-positive bacteria, especially Staphylococcus aureus with the MIC of 0.46μg/mL. The discovery of ariakemicins represents the validity of focusing on untapped microbial sources for the exploration of bioactive molecules of novel structure classes.
天然有機化合物討論会の論文
2008-09-01

P-55 Rapidithrix属海洋細菌が生産する新規抗菌性ポリケチドペプチドariakemicin類の構造(ポスター発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク