The interplay of glycogen metabolism and differentiation provides an insight into the developmental biology of Streptomyces coelicolor

Abstract

Mycelial colonies of the developmentally complex actinomycete Streptomyces coelicolor growing on solid medium contain glycogen in two distinct locations. Phase I deposits are found in a substrate mycelium region bordering the developing aerial mycelium. Their production involves GlgBI, one of two glycogen branching enzyme isoforms. Phase II deposits occur in the upper regions of aerial hyphae, in long tip cells that are dividing, or have just divided, into unigenomic prespore compartments. Their formation involves a second branching enzyme isoform, GlgBII. To find out if the gene for the second isoform, glgBII, is regulated by any of the well-studied whiA, B, G, H or I genes needed for sporulation septation, glgBI or glgBII was disrupted in a set of whi mutants, and the glycogen phenotypes examined by transmission electron microscopy. In the whiG mutants, deposits were found throughout the aerial mycelium and the adjacent region of the substrate mycelium, but the morphology of all the deposits, i.e. whether they were in the form of granules of branched glycogen or large blobs of unbranched glycan, depended solely on GlgBI. In contrast, the whiA, B, H and I mutations had no obvious effect on the pattern of glycogen deposition, or on the spatial specificity of the branching enzyme isoforms (though phase II glycogen deposits were reduced in size and abundance in the whiA and B mutants, and increased in the whiH mutant). These results indicate that glgBII is regulated (directly or indirectly) by whiG, and not by any of the other whi genes tested, and that the aerial hyphae of a whiG mutant are atypical in being physiologically similar to the substrate hyphae from which they emerge. A new role for aerial hyphae is proposed.

Polyphosphate Storage during Sporulation in the Gram-Negative Bacterium Acetonema longum

“…Homology searches. Several kinds of storage granules (SGs) have been described in bacteria, including glycogen, poly-␤-hydroxybutyrate (PHB), polyphosphate, "sulfur-rich" granules, and "nitrogen-rich" granules (18)(19)(20)(21)(22). We searched for genes encoding enzymes associated with the production of storage granules in the genomes of A. longum and a number of "control" species, including Ralstonia eutropha (known to form PHB granules) (23), Caulobacter crescentus (known to form polyphosphate granules) (24), Escherichia coli (known to store glycogen) (25), and Allochromatium vinosum (known to form sulfur globules).…”

The glgX gene product of Corynebacterium glutamicum is required for glycogen degradation and for fast adaptation to hyperosmotic stress

“…Glycogen consists of a-1,4-a-1,6-linked glucose residues (Manners, 1991), and serves as a major reserve polysaccharide in eukaryotes and in a variety of bacteria (Ball & Morell, 2003;Iglesias & Preiss, 1992). Although there have been some investigations of enzymes or genes involved in glycogen synthesis and degradation in other bacteria (Buschiazzo et al, 2004;Horcajada et al, 2006;Yeo & Chater, 2005), most studies have been done with Escherichia coli (Ballicora et al, 2003;Preiss, 1996). In this organism, glycogen is synthesized in a two-step process.…”

Structure of Streptomyces Maltosyltransferase GlgE, a Homologue of a Genetically Validated Anti-tuberculosis Target

“…For example, it is involved in carbon management in Streptomyces coelicolor (13)(14)(15). The genes of this pathway are duplicated and separately and developmentally regulated in this organism, such that each is respectively associated with transient glycogen deposition at the initiation of aerial growth (phase I) and during the first stages of sporulation (phase II).…”