Exopolysaccharide synthesis

K+ has a role in substrate uptake and during effident exopolysaccharide synthesis, adequate supplies of this ion is essential for ensuring suffident intracellular carbon substrate is maintained. Other ions, such as phosphate and magnesium, have roles in the acylation of exopolysaccharides and influence their physical properties. 

Briefly outline the major organisational features of genes encoding the enzymes responsible for exopolysaccharide synthesis, using X. campestris as the example. 

Complete the following diagram by identifying the components to give a generalised scheme for the regulation of exopolysaccharide synthesis based on die examples from X. campestris and E. coli. 

The genes responsible for encoding the proteins specifically involved in exopolysaccharide synthesis are dustered in one large operon. The genes encoding the proteins for sugar nucleotide phosphates, which are not necessarily spedfically used for exopolysaccharide synthesis, also tend to be dustered. 

Janczarek, M., and Skorupska, A., 2001, The Rhizobium leguminosarum bv. Trifolii pssB gene product is an inositol monophosphatase that influences exopolysaccharide synthesis. Arch. Microbiol. 175 143-151. 

Anderson AJ, Dawes EA (1990) Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates. Microbiol Rev 54 450 72 Aneja P, Dai M, Lacorre DA, PUlon B, Charles TC (2004) Heterologous complementation of the exopolysaccharide synthesis and carbon utilization phenotypes of Sinorhizobium meliloti Rml021 polyhydroxyalkanoate synthesis mutants. FEMS Microbiol Lett 39 277-283 Arora NK, Singhal V, Maheshwari DK (2006) Salinity-induced accumulation of poly- 3-hydroxy-butyrate in rhizobia indicating its role in cell protection. World J Microbiol Biotechnol 22 603-606... 

Vandevivere P, Kirchman DL (1993) Attachment stimulates exopolysaccharide synthesis by a bacterium. Appl Environ Microbiol 59 3280-3286 Vandevivere P (1995) Bacterial closing of porous media a new modelling approach. Bifouling 8 281—291... 

Matsukawa, M., Greenberg, E. P. Imitative exopolysaccharide synthesis genes influence P eu-domonas aeruginosa biofihn development. J Bacterial 2004,186,4449-4456. 

Sutherland, I. W. Microbial exopolysaccharide synthesis, fst Extracellular Microbial Polysaccharides, Vol. 5, Sanford, P. A., Laskin, A. (Ed.), American Chemical Society Washington DC, 1977, pp. 40-57. 

---