Prioritization of Microorganisms Isolated from the Indian Ocean Sponge Scopalina hapalia Based on Metabolomic Diversity and Biological Activity for the Discovery of Natural Products

Abstract

Despite considerable advances in medicine and technology, humanity still faces many deadly diseases such as cancer and malaria. In order to find appropriate treatments, the discovery of new bioactive substances is essential. Therefore, research is now turning to less frequently explored habitats with exceptional biodiversity such as the marine environment. Many studies have demonstrated the therapeutic potential of bioactive compounds from marine macro- and microorganisms. In this study, nine microbial strains isolated from an Indian Ocean sponge, Scopalina hapalia, were screened for their chemical potential. The isolates belong to different phyla, some of which are already known for their production of secondary metabolites, such as the actinobacteria. This article aims at describing the selection method used to identify the most promising microorganisms in the field of active metabolites production. The method is based on the combination of their biological and chemical screening, coupled with the use of bioinformatic tools. The dereplication of microbial extracts and the creation of a molecular network revealed the presence of known bioactive molecules such as staurosporin, erythromycin and chaetoglobosins. Molecular network exploration indicated the possible presence of novel compounds in clusters of interest. The biological activities targeted in the study were cytotoxicity against the HCT-116 and MDA-MB-231 cell lines and antiplasmodial activity against Plasmodium falciparum 3D7. Chaetomium globosum SH-123 and Salinispora arenicola SH-78 strains actually showed remarkable cytotoxic and antiplasmodial activities, while Micromonospora fluostatini SH-82 demonstrated promising antiplasmodial effects. The ranking of the microorganisms as a result of the different screening steps allowed the selection of a promising strain, Micromonospora fluostatini SH-82, as a premium candidate for the discovery of new drugs.

Bioprospecting for the soil-derived actinobacteria and bioactive secondary metabolites on the Western Qinghai-Tibet Plateau

“…Firstly, the antiSMASH analysis revealed the biosynthetic potential of strain A133 to produce diverse secondary metabolites including rifamycins. The visualization, clustering, and annotation of the secondary metabolites were achieved by the UPLC-QTOF-MS/MS-based molecular networking ( Le Loarer et al, 2023 ; Zhang et al, 2023 ). This method enabled us to annotate two families of compounds, namely rifamycins and zampanolides.…”

OSMAC Method to Assess Impact of Culture Parameters on Metabolomic Diversity and Biological Activity of Marine-Derived Actinobacteria

“…In order to guide a future isolation work in the quest for new molecules with therapeutic potential, this study assessed the impact of culture parameters on the metabolic diversity and biological activities of the extracts of the cultures from three preselected marine-derived actinobacteria [15,19]. The aim was to identify favorable culture parameters by varying the culture medium composition and physical state, growth duration, and nature of the solvent used for extraction.…”

“…The OSMAC approach used in this study varied the selected culture parameters, such as incubation time (7, 14, 21 days), medium composition (A1BFe+C and Marin Broth), and support type (solid and liquid cultures). The selected strains were all kept in storage cryotubes and revived before pre-culturing, according to the protocol described in Le Loarer et al (2023) [19]. Pre-cultures and final cultures were carried out in the same medium to obtain the crude extracts.…”

“…A1BFe+C medium, simplified to A1 in this article, consists of [19]. Incubation times were 7, 14, or 21 days for A1 medium and 14 days only for MB medium.…”

“…The present work develops the impact of selected culture parameters on the metabolic diversity of the microbial extracts and their associated biological activities. These three strains were preselected based on previous studies using a prioritization method or their anti-aging properties [15,19]. An OSMAC culture strategy was then set up to evaluate the impact of cultivation time, support of growth (liquid or solid), or culture medium composition on the production of microbial metabolites.…”