%0 Journal Article
%T Unified Theory of Bacterial Sialometabolism: How and Why Bacteria Metabolize Host Sialic Acids
%A Eric R. Vimr
%J ISRN Microbiology
%D 2013
%R 10.1155/2013/816713
%X Sialic acids are structurally diverse nine-carbon ketosugars found mostly in humans and other animals as the terminal units on carbohydrate chains linked to proteins or lipids. The sialic acids function in cell-cell and cell-molecule interactions necessary for organismic development and homeostasis. They not only pose a barrier to microorganisms inhabiting or invading an animal mucosal surface, but also present a source of potential carbon, nitrogen, and cell wall metabolites necessary for bacterial colonization, persistence, growth, and, occasionally, disease. The explosion of microbial genomic sequencing projects reveals remarkable diversity in bacterial sialic acid metabolic potential. How bacteria exploit host sialic acids includes a surprisingly complex array of metabolic and regulatory capabilities that is just now entering a mature research stage. This paper attempts to describe the variety of bacterial sialometabolic systems by focusing on recent advances at the molecular and host-microbe-interaction levels. The hope is that this focus will provide a framework for further research that holds promise for better understanding of the metabolic interplay between bacterial growth and the host environment. An ability to modify or block this interplay has already yielded important new insights into potentially new therapeutic approaches for modifying or blocking bacterial colonization or infection. 1. Introduction At least at some level common experience indicates to almost everyone that life is constrained by competition for limited resources. Formally trained biologists understand this competition as central to evolution, the only fundamental theory in biology. For some microorganisms competitive success in colonizing a mammalian or avian host depends upon specialized metabolism that may support growth in only certain niches. For example, Freter [1] has summarized his own and the work of others by describing the mechanisms of association of bacteria with mucosal surfaces. These mechanisms include ˇ°(a) chemotactic attraction of motile bacteria to the surface of the mucus [layer], (b) penetration and trapping within the mucus [layer], (c) adhesion to receptorsˇ­, (d) adhesion to epithelial cell surfaces, and (e) multiplication of the mucosa-associated bacteria.ˇ± The combined set of traits or phenotypes expressed by a given bacterium defines its potential ˇ°virulence factorsˇ± or relative colonization success [1, 2]. In the current paper the final stage of the host-microbial interaction is exclusively focused upon multiplication of bacteria at mucosal
%U http://www.hindawi.com/journals/isrn.microbiology/2013/816713/