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Chapter 45 : Biofilms on Living Surfaces
Recent progress in studies of the microbiology of the surfaces of marine algae and sponges has provided new insights into a series of ecological processes. This chapter presents contemporary approaches to the study of several such processes, including the establishment of community composition and diversity, gene function in complex microbial consortia, chemically mediated interactions between prokaryotes and eukaryotes, key events in bacterial interspecies competition and colonization of surfaces, and factors facilitating persistence and survival of pathogens in the environment. While several aspects of modern technologies and methods are discussed, the intent of this chapter is to familiarize the reader with such approaches in the context of the biological processes displayed by marine microbial epiphytic and epibiotic communities on living surfaces. Biofilms occur on practically all surfaces, and most bacteria can make biofilms. The formation of biofilms on living surfaces has consequences for the individual (plant or animal), and hence, a number of defenses have evolved to either prevent such colonization or recruit specific bacteria to their surface that thwart subsequent colonization by other bacteria. Bacteria are the primary colonizing organisms on surfaces and serve as a focus for the attachment and growth of other organisms within the marine environment, including complex fouling communities of invertebrates, sessile plants, and animals. Similar to other model biofilms, Pseudoalteromonas tunicata biofilms develop a complex architecture consisting of matrix-enclosed structures called microcolonies separated by a network of open water channels. The chapter focuses on biofilm formation by vibrio spp. on living surfaces.
Sampling scheme for comparing microbial community compositions in three marine sponges and surrounding seawater. Reproduced with permission from reference 96 .
DGGE-based analysis of bacterial community composition in the marine sponge Cymbastela concentrica (Cc) and seawater (Sw) from southeastern Australia. (A) 16S rRNA gene DGGE gel. Sample numbers and letters refer to collection sites and replicate sponges, respectively. The bands which were excised and sequenced are indicated 1 to 7. (B) Cluster diagram representing the presence or absence of bands in panel A. (C) Phylogenetic analysis of excised DGGE bands from panel A.