In Silico Analysis of PKS and NRPS Gene Clusters in Arisostatin- and Kosinostatin-Producers and Description of Micromonospora okii sp. nov.

Hisayuki Komaki,Akira Hosoyama,Natsuko Ichikawa,Yasuhiro Igarashi,Moriyuki Hamada

doi:10.3390/antibiotics10121447

Abstract

Micromonospora sp. TP-A0316 and Micromonospora sp. TP-A0468 are producers of arisostatin and kosinostatin, respectively. Micromonospora sp. TP-A0316 showed a 16S rRNA gene sequence similarity of 100% to Micromonospora oryzae CP2R9-1T whereas Micromonospora sp. TP-A0468 showed a 99.3% similarity to Micromonospora haikouensis 232617T. A phylogenetic analysis based on gyrB sequences suggested that Micromonospora sp. TP-A0316 is closely related to Micromonospora oryzae whereas Micromonospora TP-A0468 is an independent genomospecies. As Micromonospora sp. TP-A0468 showed some phenotypic differences to its closely related species, it was classified as a novel species, for which the name Micromonospora okii sp. nov. is proposed. The type strain is TP-A0468T (= NBRC 110461T). Micromonospora sp. TP-A0316 and M. okii TP-A0468T were both found to harbor 15 gene clusters for secondary metabolites such as polyketides and nonribosomal peptides in their genomes. Arisostatin-biosynthetic gene cluster (BGC) of Micromonospora sp. TP-A0316 closely resembled tetrocarcin A-BGC of Micromonospora chalcea NRRL 11289. A large type-I polyketide synthase gene cluster was present in each genome of Micromonospora sp. TP-A0316 and M. okii TP-A0468T. It was an ortholog of quinolidomicin-BGC of M. chalcea AK-AN57 and widely distributed in the genus Micromonospora.

Highlights

Actinomycetes are Gram-positive filamentous bacteria and its members are recognized as a rich source of bioactive secondary metabolites, many of which have been utilized for pharmaceutical purposes [1]
The relationships that exist between taxonomic species and secondary metabolites are still unclear because many strains that produce bioactive secondary metabolites have not been classified at species level
This study aimed to elucidate the taxonomic positions of both Micromonospora sp

Summary

Introduction

Actinomycetes are Gram-positive filamentous bacteria and its members are recognized as a rich source of bioactive secondary metabolites, many of which have been utilized for pharmaceutical purposes [1]. Soil is the main habitat of actinomycetes, including the genus Streptomyces, marine environments such as sea water have been identified as sites for the isolation of actinomycetal strains producing new bioactive compounds. Members of the genus Micromonospora are often isolated from marine environments and have been found to produce diverse secondary metabolites [2]. TP-A0316 produces novel compounds, named arisostatins A and B, in addition to tetrocarcin A [3] whereas Micromonospora sp. Arisostatins are new members of the tetrocarcin class of antibiotics (Figure 1a), providing antibiotic activity against Gram-positive bacteria and demonstrating antitumor activity [3]. The tetrocarcin A-biosynthetic gene cluster (BGC) was identified

Objectives

Methods

Findings

Conclusion