Cyclic AMP negatively regulates prodigiosin production by Serratia marcescens

Abstract

Many Serratia marcescens strains produce the red pigment prodigiosin, which has antimicrobial and anti-tumor properties. Previous reports suggest that cyclic AMP (cAMP) is a positive regulator of prodigiosin production. Supporting this model, the addition of glucose to growth medium inhibited pigment production in rich and minimal media. Unexpectedly, we observed highly elevated levels of prodigiosin production in isogenic strains with mutations in genes involved in cAMP production (cyaA and crr) and in cAMP-dependent transcriptional signaling (crp). Multicopy expression of the Escherichia coli camp phosphodiesterase gene, cpdA, also conferred a striking increase in prodigiosin production. Exogenous cAMP decreased both pigment production and pigA-lacZ transcription in the wild-type (WT) strain, and pigA-lacZ transcription was significantly increased in a crp mutant relative to WT. Suppressor and epistasis analysis indicate that the hyperpigment phenotype was dependent upon pigment biosynthetic genes (pigA, pigB, pigC, pigD and pigM). These experiments establish cAMP as a negative regulator of prodigiosin production in S. marcescens.

Serratia marcescens Cyclic AMP Receptor Protein Controls Transcription of EepR, a Novel Regulator of Antimicrobial Secondary Metabolites

“…Culture optical density was recorded, 1 ml of culture was transferred to a microcentrifuge tube, and the cells were pelleted. Prodigiosin was extracted from centrifuged cell pellets with 1 ml acidified ethanol (2 ml of 2 N HCl added to 98 ml of 95% ethanol), and pigment levels were measured by absorbance at 534 nm based on the method of Slater et al (33), as previously described (18).…”

“…When this construct integrates, the promoter region is duplicated such that the lacZ gene becomes a reporter for eepR expression, and the native eepR gene comes under the control of the regulatory elements in the 263 bp of DNA upstream of the ORF, maintaining EepR, which may be necessary for eepR expression. For pigA and swrW promoter analysis, transcriptional lacZ fusions to internal fragments of the pigB and swrW genes (plasmids pMQ268 and pMQ223) were targeted to the chromosome by homologous recombination, verified by PCR, and used as previously described (18,21,23).…”

“…Whereas recombinant S. marcescens CRP bound directly to the promoter of flhDC to regulate flagellum production (18), interactions were not detected between recombinant CRP and promoters of the prodigiosin biosynthetic operon (pigA-N) or the swrW gene, required for serratamolide production (18,21,23). Based on these observations, we hypothesized an intermediate regulatory protein, regulated by cAMP-CRP, that in turn regulates expression of pigA-N and swrW.…”

“…Mutation of genes involved in 3=-5=-cAMP production (cyaA) and the transcription factor that responds to cAMP (crp) confers robust phenotypes beyond catabolite repression, including increased prodigiosin production (18), elevated serratamolide pro-duction (19), increased biofilm formation through increased type I pili production (20), enhanced extracellular protease production (21), and a loss of flagellum-based motility (22). CRP similarly regulates motility, adhesion, and secondary metabolite production by such diverse bacteria as Salmonella enterica serovar Typhimurium and Streptomyces coelicolor (1)(2)(3)(4).…”

<b>Petroleum biodegrading and co-resistance to antibiotics by <i>Serratia marcescens</i> strain isolated in Coari, Amazonas

“…Serratia species have been described in the literature as being able to grow in environments containing petroleum hydrocarbons (Rojas et al, 2002; Wongsa et al, 2004;Ortega-González et al, 2013), and in environments saturated with heavy metals (Alzubaidy, 2012;Silva et al, 2012;Ibrahim, Syed, Shukor, & Ahmad, 2014). The S. marcescens specie has been reported as the most important Serratia species due to its ability to produce compounds, like prodigiosin, a natural red pigment, Serrawettina, a biotensoative that gives it adherence in the process of colonization of surfaces, and also enzymes, like as proteases, nucleases, lipases, chitinases, benzonases and cloroperoxidases (Montaner et al, 2000;Pérez-Tomás, Montaner, Llagostera, & Soto-cerrato, 2003;Morohoshi et al, 2007;Kalivoda et al, 2010). Due to the metabolic capacity of S. marcescens strains to degrade petroleum, these strains have been used alone or in microbial consortia, aiming at the recovery of environments impacted by petroleum spills and derivatives (Wongsa et al, 2004;Ortega-González et al, 2013;Silva et al, 2015).…”