Role of Acid Metabolism in
            <i>Streptomyces coelicolor</i>
            Morphological Differentiation and Antibiotic Biosynthesis

Viollier, Patrick H.; Minas, Wolfgang; Dale, Glenn E.; Folcher, Marc; Thompson, Charles J.

doi:10.1128/jb.183.10.3184-3192.2001

Cited by 68 publications

(78 citation statements)

References 47 publications

(86 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pH differences between the wild-type and rsuA mutant cultures suggest that U activity affects the normal pathways of glucose metabolism in S. coelicolor. The dependence of aerial mycelium formation on the proper control of carbon utilization has been previously demonstrated, with the finding that many bald mutants are defective in carbon catabolite repression (44) and the observation of bald phenotypes for citrate synthase (citA) and aconitase (acoA) mutants of S. coelicolor (59,60). Further elucidation of the links between the regulation of carbon metabolism, extracellular protease activity, and U may illuminate the molecular basis for the bald phenotype of the rsuA mutant.…”

Section: Discussionmentioning

confidence: 89%

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor

et al. 2008

View full text Add to dashboard Cite

The filamentous bacterium Streptomyces coelicolor forms an aerial mycelium as a prerequisite to sporulation, which occurs in the aerial hyphae. Uncontrolled activity of the extracytoplasmic function sigma factor U blocks the process of aerial mycelium formation in this organism. Using a green fluorescent protein transcriptional reporter, we have demonstrated that sigU transcription is autoregulated. We have defined a U -dependent promoter sequence and used this to identify 22 likely U regulon members in the S. coelicolor genome. Since many of these genes encode probable secreted proteins, we characterized the extracellular proteome of a mutant with high U activity caused by disruption of rsuA, the presumed cognate anti-sigma factor of U . This mutant secreted a much greater quantity and diversity of proteins than the wild-type strain. Peptide mass fingerprinting was used to identify 79 proteins from the rsuA mutant culture supernatant. The most abundant species, SCO2217, SCO0930, and SCO2207, corresponded to secreted proteins or lipoproteins of unknown functions whose genes are in the proposed U regulon. Several unique proteases were also detected in the extracellular proteome of the mutant, and the levels of the protease inhibitor SCO0762 were much reduced compared to those of the wild type. Consequently, extracellular protease activity was elevated about fourfold in the rsuA mutant. The functions of the proteins secreted as a result of U activity may be important for combating cell envelope stress and modulating morphological differentiation in S. coelicolor.The Streptomyces species of gram-positive soil bacteria exhibit a complex life cycle that culminates in the production of unigenomic spores by sporulation of multigenomic, filamentous hyphae (8,56). While vegetative growth is characterized by the extension and branching of hyphae over and into the substratum, sporulation requires the construction of a distinct aerial mycelium composed of aerial hyphae that project above the colony surface. A number of mutants of the model organism Streptomyces coelicolor that fail to form an aerial mycelium have been described; these so-called bald (bld) mutants often have defects in antibiotic production, which is another hallmark of this genus. Many of the corresponding bld genes have been identified, and most are predicted to encode regulatory proteins (reviewed in reference 9).A growing body of evidence suggests that pathways mediating environmental stress responses and morphological development are linked in S. coelicolor (9,19,31,35,36,62). The functions of alternative sigma factors appear to play an important role in connecting these processes. The S. coelicolor genome encodes 65 sigma factors (4

show abstract

Section: Discussionmentioning

confidence: 89%

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Strong evidence comes from a triple mutant blocked in citrate synthase, aconitase, and isocitrate dehydrogenase; this mutant sporulates very poorly and lacks Spo0AϳP-mediated functions (54). Furthermore, there is evidence that citrate synthase function may be involved, indirectly, in morphological differentiation and antibiotic biosynthesis of S. coelicolor, although the mechanism by which this effect occurs is not clear (55) and that Krebs cycle function regulates adhesion and virulence factor expression in Staphylococcus aureus (56). Our previous finding that thiamine limita- tion leads to down-regulation of the Gac/Rsm pathway in P. fluorescens CHA0 may also be due to an underlying metabolic deficiency in the Krebs cycle (21).…”

Section: Discussionmentioning

confidence: 99%

Small RNA-dependent Expression of Secondary Metabolism Is Controlled by Krebs Cycle Function in Pseudomonas fluorescens

Takeuchi

Kiefer

Reimmann

et al. 2009

Journal of Biological Chemistry

View full text Add to dashboard Cite

Pseudomonas fluorescens CHA0, an antagonist of phytopathogenic fungi in the rhizosphere of crop plants, elaborates and excretes several secondary metabolites with antibiotic properties. Their synthesis depends on three small RNAs (RsmX, RsmY, and RsmZ), whose expression is positively controlled by the GacS-GacA two-component system at high cell population densities. To find regulatory links between primary and secondary metabolism in P. fluorescens and in the related species Pseudomonas aeruginosa, we searched for null mutations that affected central carbon metabolism as well as the expression of rsmY-gfp and rsmZ-gfp reporter constructs but without slowing down the growth rate in rich media. Mutation in the pycAB genes (for pyruvate carboxylase) led to down-regulation of rsmXYZ and secondary metabolism, whereas mutation in fumA (for a fumarase isoenzyme) resulted in up-regulation of the three small RNAs and secondary metabolism in the absence of detectable nutrient limitation. These effects required the GacS sensor kinase but not the accessory sensors RetS and LadS. An analysis of intracellular metabolites in P. fluorescens revealed a strong positive correlation between small RNA expression and the pools of 2-oxoglutarate, succinate, and fumarate. We conclude that Krebs cycle intermediates (already known to control GacA-dependent virulence factors in P. aeruginosa) exert a critical trigger function in secondary metabolism via the expression of GacA-dependent small RNAs.Secondary metabolism occurs in certain bacteria and fungi as part of developmental processes, which are often accompanied by morphological changes (1, 2). In natural environments, secondary metabolites are believed to confer a selective advantage to the producers when these organisms cannot rely on their full growth potential to compete with other organisms (3). Such a role is most plausible for secondary metabolites having antibiotic activities (4). In pure cultures, secondary metabolites are non-essential for the producers and are typically formed when cell population densities are high and growth is restricted. This distinct production phase, sometimes called idiophase, usually follows the phase of optimal growth, also termed trophophase (5). A fundamental question is what triggers the onset of the idiophase. Both extracellular and intracellular signal molecules are known to be involved. For instance, excreted quorum-sensing signal molecules, such as N-acyl-homoserine lactones of Pseudomonas species or ␥-butyrolactones of Streptomyces species, positively regulate the expression of antibiotic compounds, and the intracellular alarmone ppGpp is required for antibiotic production in Streptomyces coelicolor under conditions of nitrogen starvation (1, 6). However, these findings do not provide a generally valid picture of how secondary metabolism is initiated in microorganisms. For instance, some Pseudomonas species produce secondary metabolites without N-acyl-homoserine lactones and phosphate-limited S. coelicolor does not rely on ppGpp for antibio...

show abstract

“…In previous studies, the morphological differentiation of some S. coelicolor A3(2) mutants was inhibited by acidification of the medium, and the addition of appropriate buffers to the medium allowed these mutants to develop normally (44,48,49). Therefore, we added 50 mM HEPES or TES [N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid] to the YMP-GL solid medium to maintain the pH at ϳ7.5.…”

Section: Fig 5 Transcriptional Analysis Of Cebe and Cebr (A)mentioning

confidence: 99%

CebR as a Master Regulator for Cellulose/Cellooligosaccharide Catabolism Affects Morphological Development in Streptomyces griseus

2009

View full text Add to dashboard Cite

Streptomyces griseus mutants exhibiting deficient glucose repression of ␤-galactosidase activity on lactosecontaining minimal medium supplemented with a high concentration of glucose were isolated. One of these mutants had a 12-bp deletion in cebR, which encodes a LacI/GalR family regulator. Disruption of cebR in the wild-type strain caused the same phenotype as the mutant, indicating that CebR is required for glucose repression of ␤-galactosidase activity. Recombinant CebR protein bound to a 14-bp inverted-repeat sequence (designated the CebR box) present in the promoter regions of cebR and the putative cellobiose utilization operon, cebEFG-bglC. The DNA-binding activity of CebR was impaired by cellooligosaccharides, including cellobiose, cellotriose, cellotetraose, cellopentaose, and cellohexaose. In agreement with this observation, transcription from the cebE and cebR promoters was greatly enhanced by the addition of cellobiose to the medium. Seven other genes containing one or two CebR boxes in their upstream regions were found in the S. griseus genome. Five of these genes encode putative secreted proteins: two cellulases, a cellulose-binding protein, a pectate lyase, and a protein of unknown function. These five genes and cebEFG-bglC were transcribed at levels 4 to 130 times higher in the ⌬cebR mutant than in the wild-type strain, as determined by quantitative reverse transcription-PCR. These findings indicate that CebR is a master regulator of cellulose/cellooligosaccharide catabolism. Unexpectedly, the ⌬cebR mutant formed very few aerial hyphae on lactose-containing medium, demonstrating a link between carbon source utilization and morphological development.

show abstract

Role of Acid Metabolism in Streptomyces coelicolor Morphological Differentiation and Antibiotic Biosynthesis

Cited by 68 publications

References 47 publications

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor

Small RNA-dependent Expression of Secondary Metabolism Is Controlled by Krebs Cycle Function in Pseudomonas fluorescens

CebR as a Master Regulator for Cellulose/Cellooligosaccharide Catabolism Affects Morphological Development in Streptomyces griseus

Contact Info

Product

Resources

About

Role of Acid Metabolism in Streptomyces coelicolor Morphological Differentiation and Antibiotic Biosynthesis

Cited by 68 publications

References 47 publications

Secreted-Protein Response to σUActivity inStreptomyces coelicolor

Secreted-Protein Response to σUActivity inStreptomyces coelicolor

Small RNA-dependent Expression of Secondary Metabolism Is Controlled by Krebs Cycle Function in Pseudomonas fluorescens

CebR as a Master Regulator for Cellulose/Cellooligosaccharide Catabolism Affects Morphological Development in Streptomyces griseus

Contact Info

Product

Resources

About

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor

Secreted-Protein Response to σ^UActivity inStreptomyces coelicolor