Sponge-Associated Actinomycetes as Potential Sources of Bioactive Natural Products for Drug Discovery

Project Number
RI 2/14 TLT

Project Duration
March 2015 - December 2017


As sessile and filter-feeding metazoans, marine sponges represent an ecologically important and highly diverse component of marine benthic communities. It has been suggested that marine sponges are hosts to many microorganisms which can constitute up to 40-60% of its biomass. Recently, sponges have attracted a high interest from the scientific community due to two important factors: sponges have a wide range of associated bacteria and they are a rich source of biomedically important natural products. A number of bioactive molecules with various pharmacological functions, ranging from anti-infective to anticancer properties, have been isolated from marine sponges. Many of these substances were subsequently shown to be actually synthesized by sponge-associated bacteria. In spite of a number of reports on the diversity and biotechnological potential of sponge-associated bacteria, to date no information is available on the nature of bacteria associated with local sponge species. As such, the PI and students at NIE initiated a series of small scale pilot projects to assess the biomedical potential of marine bacteria associated with three marine sponge species found at Kusu Island, Singapore. Preliminary data indicated these sponges to harbor diverse bacterial community and a number of selected marine bacterial strains were shown to produce bioactive molecules. Encouraged by these early data, the present project is being proposed to expand research on sponge associated sponges by increasing the number of sponge species as well as the chemical nature of bioactive natural products derived from isolated bacterial strains. Using culture dependent method, based on various marine culture media selective for marine actinomycetes, the bacterial symbionts will be isolated from sponge samples and identified based on their 16S rRNA gene sequences. In addition, these marine bacterial strains will be screened for biological activities using in-house bioassays, including the brine shrimp toxicity assay and anti-microbial assay. Marine bacterial strains that displayed significant biological properties will be selected for large scale fermentation for the isolation and purification of natural products. The chemical structures of bacterial derived molecules will be elucidated using various spectroscopic techniques, such as mass spectroscopy and 1D and 2D NMR spectroscopy. This project on sponge associated bacteria is interdisciplinary in nature and unprecedented in scope. Data generated from this research will spur further research in several areas, particularly on marine microbial ecology, conservation biology, and biotechnology.

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