Microbial Symbionts in Marine Sponges

Our oceans are rich with biological and chemical diversity a large amount of which is still waiting to be discovered. From relatively limited knowledge of marine plants, animals and microbes we have already identified more than 12,000 novel chemicals. The possibilities of us finding more useful chemicals for things like: pharmaceuticals, cosmetics and enzymes are very promising. Sponges are well known to harbour diverse microbial communities and represent a significant source of bioactive compounds. Recent studies of the microbial communities associated with marine sponges have identified a number of new species and an array of new chemical compounds.

Sponges are among the most primitive of multicellular animals. There around approximately 15,000 species of sponge (phylum Porifera) found in our marine environments. Sponges filter particles from water as their primary source for nutrients. They are so abundant that collectively the amount of water they filter is considered to have great ecological importance. They exhibit a vast array of secondary metabolites to carry out functions for example deterring predators, communication and protection against infection. Some of these secondary metabolites have been identified to have anticancer properties making them the subject of much research.

It has often been believed that many products from larger organisms are actually derived from microbial sources. Recent research has identified significant similarities between hosts and their associated microorganisms. Bacteria-sponge associations present a promising source for bioactive compounds. One of the most significant problems that have hindered the search for secondary metabolites is their low concentration. In marine invertebrates many compounds are only found at concentrations of less than 0.00001% of the body weight. So understandable they are very hard to isolate and identify. Compounds that we have already sourced from sponges are suspected to actually be produced by bacterial symbionts due to the resemblance of known bacterial products. This presents very exciting possibilities for large scale production of these compounds because they will be much easier to cultivate then sponges. The symbionts could be cultured or the biosynthetic genes could be transferred into culturable bacteria.

The paper has very limited detailed information. It primarily made up of broad statements which are, in many cases, not backed up with facts, figures or references. However the paper does introduce a very interesting field of marine microbe research highlighting the exciting possibilities for natural products being exploited for our benefit.

A review of: Agus Sabdono. (2008). Microbial Symbionts in Marine Sponges: marine natural product factory . Journal of Costal Development. 11 (2), 57-61