Proximicin A, B and C, Novel Aminofuran Antibiotic and Anticancer Compounds Isolated from Marine Strains of the Actinomycete Verrucosispora†

Abstract

A family of three novel aminofuran antibiotics named as proximicins was isolated from the marine Verrucosispora strain MG-37. Proximicin A was detected in parallel in the marine abyssomicin producer "Verrucosispora maris" AB-18-032. The characteristic structural element of proximicins is 4-amino-furan-2-carboxylic acid, a hitherto unknown g -amino acid. Proximicins show a weak antibacterial activity but a strong cytostatic effect to various human tumor cell lines.

Analytical characterization and structure elucidation of metabolites from Aspergillus ochraceus MP2 fungi

“…These structures suggest most of the metabolites to be derived from metabolic pathways is also common to terrestrial fungi. Such a similarity is, for example, obvious for sesquiterpenes of the hirsutane-type [16] . Studies show that secondary metabolites in sponges play a crucial role in their survival in the marine ecosystem.…”

“…Although the natual function is not known, it is assumed that they play an important role in chemical defense and communication of the organism [16] . Many of them have been suggested to act as pheromones, antifeedants or repellents and regulators in the development of organisms.…”

Terpenoids produced by actinomycetes: isolation, structural elucidation and biosynthesis of new diterpenes, gifhornenolones A and B from Verrucosispora gifhornensis YM28-088

“…[2][3][4] In addition, proximicin A produced by the same strain was reported to show antitumor activities. 5,6 Examples of bioactive metabolites isolated from the genus Verrucosispora were, however, quite limited presumably due to limited distribution of the genus Verrucosispora in the marine environment.…”

Prauserella shujinwangii sp. nov., from a desert environment

“…The study of organisms from unique, untapped ecological niches, such as deep-sea, salt lakes and deserts, provides an efficient approach for identification of novel microbes which have the significant potential for producing unique active compounds. The most significant examples include the isolation of strains representing members of the genera Salinispora and Verrucosispora from marine sediments, producing salinosporamides and abyssomicins, respectively (Bister et al, 2004;Buck, 1982; Fenical et al, 2009;Fiedler et al, 2008;Goodfellow & Fiedler, 2010;Keller et al, 2007;Maldonado et al, 2005;Riedlinger et al, 2004;Wang et al, 2013;Williams et al, 2005). Our laboratory has been devoted to systematics-guided bioprospecting for discovery of antiinfective natural products from actinomycetes, especially the rare ones from sea sediments, salt lakes and deserts (Bian et al, 2009; Dai et al, 2010;Mao et al, 2011; Wang et al, 2010).…”

“…Rare actinomycetes are usually regarded as the actinomycete strains with a lower isolation frequency than the members of the genus Streptomyces isolated by conventional methods (Fiedler et al, 2008;Kurtböke, 2012). The identification of rare actinomycetes of previously underrepresented genera from unexplored environments is considered to be an effective avenue for discovery of novel antibiotics (Tiwari & Gupta, 2012).…”