Exploiting the diverse microbial ecology of marine sponges
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Date
2013
Authors
Jackson, Stephen A.
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Publisher
University College Cork
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Abstract
Marine sponges (phylum Porifera) are the oldest extant metazoan animals on earth and host
large populations of symbiotic microbes: Bacteria, Archaea and unicellular Eukaryota. Those
microbes play ecological functions which are essential to the health of the host including
carbon, nitrogen and sulfur cycling as well as host defence through the production of
bioactive secondary metabolites which protect against infection and predation. The diversity
of sponge-associated microbes is remarkable with thousands of OTUs reported from
individual sponge species. Amongst those populations are sponge-specific microbes which
may be specific to sponges or specific to sponge species.
While marine natural product discovery concerns many animal phyla, Porifera account for
the largest proportion of novel compounds. Evidence suggests that many of these compounds
are the products of symbiotic microbes.
Descriptions of sponge-associated microbial community structures have been advanced by
the development of next-generation sequencing technologies while the discovery and
exploitation of sponge derived bioactive compounds has increased due to developments in
sequence-based and function-based metagenomics.
Here, we use pyrosequencing to describe the bacterial communities associated with two
shallow, temperate water sponges (Raspailia ramosa and Stelligera stuposa) from Irish
coastal waters and to describe the bacterial and archaeal communities of a single sponge
species (Inflatella pellicula) from two different depths in deep waters in the Atlantic Ocean,
including at a depth of 2900m, a depth far greater than that of any previous sequence-based
sponge-microbe investigation. We identified diverse microbial communities in all sponges
and the presence of sponge-specific taxa recruiting to previously described and novel spongespecific
clusters. We also identified archaeal communities which dominated sponge-microbe
communities. We demonstrate that sponge-associated microbial communities differ from
seawater communities indicating host selection processes.
We used sequence-based metagenomic techniques to identify genes of potential industrial
and pharmacological interest in the metagenomes of various sponge species and functionbased
metagenomic screening in an attempt to identify lipolytic and antibacterial activities
from metagenomic clones from the metagenome of the marine sponge Stelletta normani.
In addition we have cultured diverse bacterial species from sponge tissues, many of which
display antimicrobial activities against clinically relevant bacterial and yeast test strains.
Other isolates represent novel species in the genus Maribacter and require emendments to the
description of that genus.
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Keywords
Marine sponges , Porifera , Metazoa , Symbiotic microbes , Sponge derived bioactive compounds , Metagenomics , Pyrosequencing , Raspailia ramosa , Stelligera stuposa , Inflatella pellicula , Stelletta normani , Maribacter
Citation
Jackson, S. A. 2013. Exploiting the diverse microbial ecology of marine sponges. PhD Thesis, University College Cork.