Diversity of Actinobacteria Associated with the Marine Ascidian Eudistoma toealensis

Abstract

Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudistoma toealensis from Micronesia has been identified as the source of a series of staurosporine derivatives, though the exact origin of these derivatives is still unknown. To identify known staurosporine-producing microbes associated with E. toealensis, we analyzed with 16S rRNA gene tag pyrosequencing the overall bacterial community and focused on potential symbiotic bacteria already known from other ascidians or other marine hosts, such as sponges. The described microbiota was one of very high diversity, comprising 43 phyla: two from archaea, 34 described bacterial phyla, and seven candidate bacterial phyla. Many bacteria, which are renowned community members of other ascidians and marine holobionts, such as sponges and corals, were also part of the E. toealensis microbial community. Furthermore, two known producers of indolocarbazoles, Salinispora and Verrucosispora, were found with high abundance exclusively in the ascidian tissue, suggesting that microbial symbionts and not the organism itself may be the true producers of the staurosporines in E. toealensis.

Taxonomic and Metabolite Diversity of Actinomycetes Associated with Three Australian Ascidians

“…Other culture-independent ascidian microbiome studies from different geographical regions, including Asian-Pacific, South Pacific, and the Caribbean, reported similar phylum distributions, where Proteobacteria were generally reported as the most dominant phylum and also Cyanobacteria were commonly found in high abundance [9,17,19,[47][48][49]. Actinobacteria were usually reported in lower numbers in these studies.…”

Origins and Bioactivities of Natural Compounds Derived from Marine Ascidians and Their Symbionts

“…The genus Streptomyces is known as the most diverse actinomycete that widely exists in the ascidians E. turbinata and Molgula manhattensis, respectively (Figure 17) [129,130]. By analyzing the overall bacterial communities of the ascidian Eudistoma toealensis, the genera Salinispora and Verrucosispora were found to be the most notable colonies in the host [131]. These two actinomycetes are known for their production of indolocarbazole, which also has been isolated from the ascidian L. patella and enables it to be cultured in vitro [103].…”

In silico and in vitro research of potential antineoplastic amino acid derivatives of indolocarbazol glycosides properties

“…В настоящее время проходят II-III фазы клинических испытаний разработанные на основе соединений этого класса производные противоопухолевого антибиотика ребеккамицина эдотекарин и бекатекарин, производное алкалоида стауроспорина мидостаурин [6]. Тем не менее продолжается поиск новых противоопухолевых агентов класса индолокарбазолов путем выделения из природных источников методами химического синтеза [7][8][9]. Введение различных заместителей в молекулу индолокарбазола, в первую очередь к атомам азота индола и / или имидного атома азота 5-членного цикла, позволяет модулировать физико-химические и биологические свойства полученных соединений [10].…”