RESUMO
Pseudomonas aeruginosa isolates from cystic fibrosis patients are often mucoid (due to the overexpression of exopolysaccharide alginate) yet lost motility. It remains unclear about how P. aeruginosa coordinately regulates alginate production and the type IV pili-driven twitching motility. Here we showed that sigma 22 factor (AlgT/U), an activator of alginate biosynthesis, repressed twitching motility by inhibiting the expression of pilin (PilA) through the intermediate transcriptional regulator AmrZ, which directly bound to the promoter region of pilA in both mucoid strain FRD1 and non-mucoid strain PAO1. Four conserved AmrZ-binding sites were found in pilA promoters among 10 P. aeruginosa strains although their entire pilA promoters had low identity. AmrZ has been reported to be essential for twitching in PAO1. We found that AmrZ was also required for twitching in mucoid FRD1, yet a high level of AmrZ inhibited twitching motility. This result was consistent with the phenomenon that twitching is frequently repressed in mucoid strains, in which the expression of AmrZ was highly activated by AlgT. Additionally, AlgT also inhibited the transcription of pilMNOP operon, which is involved in efficient pilus assembly. Our data elucidated a mechanism for how AlgT and AmrZ coordinately controlled twitching motility in P. aeruginosa.
Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Pseudomonas aeruginosa/citologia , Pseudomonas aeruginosa/metabolismo , Fator sigma/metabolismo , Fatores de Transcrição/metabolismo , Alginatos/metabolismo , Proteínas de Bactérias/genética , Fibrose Cística/microbiologia , Proteínas de Fímbrias/genética , Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Humanos , Óperon , Regiões Promotoras Genéticas , Pseudomonas aeruginosa/genética , Fator sigma/genética , Fatores de Transcrição/genéticaRESUMO
Cyclic diguanosine monophosphate (c-di-GMP) is an important second messenger involved in bacterial switching from motile to sessile lifestyles. In the opportunistic pathogen Pseudomonas aeruginosa, at least 40 genes are predicted to encode proteins for the making and breaking of this signal molecule. However, there is still paucity of information concerning the systemic expression pattern of these genes and the functions of uncharacterized genes. In this study, we analyzed the phylogenetic distribution of genes from P. aeruginosa that were predicted to have a GGDEF domain and found five genes (PA5487, PA0285, PA0290, PA4367, and PA5017) with highly conserved distribution across 52 public complete pseudomonad genomes. PA5487 was further characterized as a typical diguanylate cyclase (DGC) and was named dgcH A systemic analysis of the gene expression data revealed that the expression of dgcH is highly invariable and that dgcH probably functions as a conserved gene to maintain the basal level of c-di-GMP, as reinforced by gene expression analyses. The other four conserved genes also had an expression pattern similar to that of dgcH The functional analysis suggested that PA0290 encoded a DGC, while the others functioned as phosphodiesterases (PDEs). Our data revealed that there are five DGC and PDE genes that maintain the basal level of c-di-GMP in P. aeruginosaIMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen that can cause infections in animals, humans, and plants. The formation of biofilms by P. aeruginosa is the central mode of action to persist in hosts and evade immune and antibiotic attacks. Cyclic-di-GMP (c-di-GMP) is an important second messenger involved in the regulation of biofilm formation. In P. aeruginosa PAO1 strain, there are around 40 genes that encode enzymes for making and breaking this dinucleotide. A major missing piece of information in this field is the phylogeny and expression profile of those genes. Here, we took a systemic approach to investigate this mystery. We found that among 40 c-di-GMP metabolizing genes, 5 have well-conserved phylogenetic distribution and invariable expression profiles, suggesting that there are enzymes required for the basal level of c-di-GMP in P. aeruginosa This study thus provides putative therapeutic targets against P. aeruginosa infections.
Assuntos
GMP Cíclico/análogos & derivados , GMP Cíclico/classificação , GMP Cíclico/genética , Diester Fosfórico Hidrolases/metabolismo , Fósforo-Oxigênio Liases/metabolismo , Filogenia , Pseudomonas aeruginosa/metabolismo , Transcriptoma , Proteínas de Bactérias/classificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , GMP Cíclico/metabolismo , Proteínas de Escherichia coli , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/genética , Genoma Bacteriano , Metanálise como Assunto , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , VirulênciaRESUMO
Zn lactate and SnF2 were used as active compounds in the dentifrice. Here, their anti-biofilm effects were evaluated on Pseudomonas aeruginosa, Acinetobacter baumannii and Streptococcus mutans. The biofilm prevention/dispersal assay of P. aeruginosa PAO1 demonstrated that Zn lactate and SnF2 can inhibit biofilm formation independently or by combined treatment. Zn lactate disrupted extracellular polysaccharides matrix formation and SnF2 reduced the biomass of biofilm. Most importantly, the combination of Zn lactate and SnF2 thoroughly abolished the biofilm formation of all three strains.
