Novel Functions of (p)ppGpp and Cyclic di-GMP in Mycobacterial Physiology Revealed by Phenotype Microarray Analysis of Wild-Type and Isogenic Strains of Mycobacterium smegmatis
| Autor: | Kuldeepkumar Ramnaresh Gupta, Sanjay Kasetty, Dipankar Chatterji |
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| Rok vydání: | 2015 |
| Předmět: |
Cyclic di-GMP
Surface Properties Physiology Mycobacterium smegmatis Virulence Guanosine Tetraphosphate Biology medicine.disease_cause Applied Microbiology and Biotechnology Bacterial Adhesion Microbiology Ligases chemistry.chemical_compound medicine Cyclic GMP Phospholipids Microbiology & Cell Biology Microbial Viability Ecology Pseudomonas aeruginosa Guanosine Pentaphosphate Wild type Biofilm Phenotype microarray Microarray Analysis biology.organism_classification Anti-Bacterial Agents Quorum sensing Phenotype chemistry Biochemistry Biofilms Chromatography Thin Layer Glycolipids Gene Deletion Locomotion Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 81:2571-2578 |
| ISSN: | 1098-5336 0099-2240 |
| Popis: | The bacterial second messengers (p)ppGpp and bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) regulate important functions, such as transcription, virulence, biofilm formation, and quorum sensing. In mycobacteria, they regulate long-term survival during starvation, pathogenicity, and dormancy. Recently, a Pseudomonas aeruginosa strain lacking (p)ppGpp was shown to be sensitive to multiple classes of antibiotics and defective in biofilm formation. We were interested to find out whether Mycobacterium smegmatis strains lacking the gene for either (p)ppGpp synthesis (Δ rel Msm ) or c-di-GMP synthesis (Δ dcpA ) would display similar phenotypes. We used phenotype microarray technology to compare the growth of the wild-type and the knockout strains in the presence of several antibiotics. Surprisingly, the Δ rel Msm and Δ dcpA strains showed enhanced survival in the presence of many antibiotics, but they were defective in biofilm formation. These strains also displayed altered surface properties, like impaired sliding motility, rough colony morphology, and increased aggregation in liquid cultures. Biofilm formation and surface properties are associated with the presence of glycopeptidolipids (GPLs) in the cell walls of M. smegmatis . Thin-layer chromatography analysis of various cell wall fractions revealed that the levels of GPLs and polar lipids were reduced in the knockout strains. As a result, the cell walls of the knockout strains were significantly more hydrophobic than those of the wild type and the complemented strains. We hypothesize that reduced levels of GPLs and polar lipids may contribute to the antibiotic resistance shown by the knockout strains. Altogether, our data suggest that (p)ppGpp and c-di-GMP may be involved in the metabolism of glycopeptidolipids and polar lipids in M. smegmatis . |
| Databáze: | OpenAIRE |
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