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Showing papers on "Salinispora arenicola published in 2013"


Journal ArticleDOI
TL;DR: A polyphasic analysis was carried out to clarify the taxonomic status of four marine actinomycete strains that share a phylogenetic relationship and phenotypic characteristics with the genus Salinispora, and it is proposed that the strains be designated as Salinisporapacifica sp.
Abstract: A polyphasic analysis was carried out to clarify the taxonomic status of four marine actinomycete strains that share a phylogenetic relationship and phenotypic characteristics with the genus Salinispora. These strains formed a distinct lineage within the Salinispora 16S rRNA and gyrB trees and were found to possess a range of phenotypic properties and DNA:DNA hybridization values that distinguished them from the type strains of the two validly named species in this genus, Salinispora tropica (CNB-440T, ATCC BAA-916T) and Salinispora arenicola (CNH-643T, ATCC BAA-917T). The combined genotypic and phenotypic data support this conclusion. It is proposed that the strains be designated as Salinispora pacifica sp. nov., the type strain of which is CNR-114T (DSMZ YYYYT = KACC 17160T).

47 citations


Journal ArticleDOI
TL;DR: Phylogenetic congruence and a well-supported concatenated tree provide strong support for the delineation of the three species as currently described and the basal relationship of Salinispora arenicola to the more recently diverged sister taxa S. tropica and S. pacifica.
Abstract: The three closely related species that currently comprise the genus Salinispora were analyzed using a multilocus sequence typing approach targeting 48 strains derived from four geographic locations. Phylogenetic congruence and a well-supported concatenated tree provide strong support for the delineation of the three species as currently described and the basal relationship of Salinispora arenicola to the more recently diverged sister taxa S. tropica and S. pacifica. The phylogeny of the initial region of the rpoB gene sequenced was atypical, placing the related genera Micromonospora and Verrucosispora within the Salinispora clade. This phylogenetic incongruence was subsequently ascribed to a homologous-recombination event in a portion of the gene associated with resistance to compounds in the rifamycin class, which target RpoB. All S. arenicola strains produced compounds in this class and possessed resistance-conferring amino acid changes in RpoB. The phylogeny of a region of the rpoB gene that is not associated with rifamycin resistance was congruent with the other housekeeping genes. The link between antibiotic resistance and homologous recombination suggests that incongruent phylogenies provide opportunities to identify the molecular targets of secondary metabolites, an observation with potential relevance for drug discovery efforts. Low ratios of interspecies recombination to mutation, even among cooccurring strains, coupled with high levels of within-species recombination suggest that the three species have been described in accordance with natural barriers to recombination.

28 citations


Journal ArticleDOI
TL;DR: The developmental cycle of the obligate marine antibiotic producer actinobacterium Salinispora arenicola isolated from a Great Barrier Reef marine sponge was investigated in relation to mycelium and spore ultrastructure, synthesis of rifamycin antibiotic compounds, and expression of genes correlated with spore formation and with r ifamycin precursor synthesis.
Abstract: The developmental cycle of the obligate marine antibiotic producer actinobacterium Salinispora arenicola isolated from a Great Barrier Reef marine sponge was investigated in relation to mycelium and spore ultrastructure, synthesis of rifamycin antibiotic compounds, and expression of genes correlated with spore formation and with rifamycin precursor synthesis. The developmental cycle of S. arenicola M413 on solid agar medium was characterized by substrate mycelium growth, change of colony color, and spore formation; spore formation occurred quite early in colony growth but development of black colonies occurred only at late stages, correlated with a change in spore maturity in relation to cell wall layers. Rifamycins were detected throughout the growth cycle, but changed in relative quantity at particular phases in the cycle, with a marked increase after 32 days. Expression of the spore division gene ssgA and the rifK gene for 3-amino-5-hydroxybenzoate synthase responsible for rifamycin precursor synthesis was seen even at early stages of the growth cycle. ssgA expression significantly increased between days 26 and 31, but rifK expression effectively remained constant throughout the growth cycle, consistent with the early synthesis of rifamycin. Factors other than precursor synthesis may be responsible for an observed late increase in rifamycin production. A useful approach for measuring and exploring the regulation of antibiotic synthesis and gene expression in the marine natural product producer S. arenicola has been established.

15 citations