Marine Spong
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Part A | 8.1
8. Marine Sponges – Molecular Biology
and Biotechnology
Stephen A. Jackson, Jonathan Kennedy, Lekha Menon Margassery, Burkhardt Flemer, Niall O’Leary,
John P. Morrissey, Fergal O’Gara, Alan D. W. Dobson
Marine sponges are an ancient and diverse
animal phylum that host well-established symbiotic microbial communities. The vast majority
of the microbial genetic diversity in sponges is,
however, currently inaccessible by traditional
methods. This large genetic resource may be of
use for biotechnological applications, particularly
as the physicochemical parameters under which
the genes within these microbes function are
likely to dictate that they may be significantly
different from similar genes or gene products
currently in use in industry, offering in some instances improved performance. Emerging tools
and technologies in the field of metagenomics
offer enormous potential for the discovery and
exploitation of new biosynthetic entities. Both
sequence-based and function-based technologies have to date been employed to identify genes
with novel or improved functions. Marine sponges,
as well-recognized sources of novel marine natural products with varied applications, are the
ideal target for the implementation of these new
technologies. We detail here some successes in
the discovery and development of marine natural
products for industrial or pharmaceutical applications and we also highlight some technical
impediments to gene and gene product exploitation which as yet still need to be overcome.
8.1 Marine Sponges .................................... 219
8.1.1 Sponge Anatomy and Physiology ... 220
8.1.2 Sponge Skeletons ......................... 220
8.1.3 Sponge Cell Types ......................... 220
8.1.4 Sponge Physiology ....................... 220
8.2 Sponge-Associated Microorganisms ....... 222
8.2.1 Sponge-Associated Bacteria .......... 222
8.2.2 Sponge-Associated Archaea .......... 225
8.2.3 Sponge-Associated Eukaryota ....... 225
8.2.4 Sponge-Specific Microorganisms ... 227
8.3 Symbiotic Functions
of Sponge-Associated Microorganisms ... 227
8.3.1 Molecular Methods to Elucidate
Sponge Symbiont Functions .......... 227
8.3.2 Discrimination Between Food
Microbes and Symbiotic Microbes .. 228
8.4 Biotechnological Potential
of Marine Sponges –
Pharmacological Potential ..................... 229
8.5 Exploiting the Pharmacological Potential
of Marine Sponges ................................ 229
8.6 Metagenomic Strategies
for Natural Product Discovery ................ 230
8.6.1 Functional Screening
of Large-Insert Metagenomic Clone
Libraries ...................................... 233
8.6.2 Problems Associated
with Functional Screening
of Metagenomic Libraries.............. 236
8.6.3 Sequence-Based Screening
of Metagenomic Libraries
to Identify Novel Biocatalysts ........ 237
8.6.4 Sequence-Based Screening
of Metagenomic Libraries
to Identify Genes Involved
in the Biosynthesis of Natural
Products...................................... 239
8.7 Conclusions .......................................... 243
References................................................... 243
8.1 Marine Sponges
Marine sponges (phylum Porifera) are the oldest extant metazoan animals (Fig. 8.1), with the oldest fossils
dating back almost 630 million years [8.1]. Sponges
are globally distributed (Fig. 8.2) and are impor-