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A bacterial cytokine
G V Mukamolova1, A S Kaprelyants, D I Young
1Bakh Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr.33, 117071 Moscow, Russia.
Abstract:
Viable cells of Micrococcus luteus secrete a factor, which promotes the resuscitation and growth of dormant, nongrowing cells of the same organism. The resuscitation-promoting factor (Rpf) is a protein, which has been purified to homogeneity. In picomolar concentrations, it increases the viable cell count of dormant M. luteus cultures at least 100-fold and can also stimulate the growth of viable cells. Rpf also stimulates the growth of several other high G+C Gram-positive organisms, including Mycobacterium avium, Mycobacterium bovis (BCG), Mycobacterium kansasii, Mycobacterium smegmatis, and Mycobacterium tuberculosis. Similar genes are widely distributed among high G+C Gram-positive bacteria; genome sequencing has uncovered examples in Mycobacterium leprae and Mb. tuberculosis and others have been detected by hybridization in Mb. smegmatis, Corynebacterium glutamicum, and Streptomyces spp. The mycobacterial gene products may provide different targets for the detection and control of these important pathogens. This report is thus a description of a proteinaceous autocrine or paracrine bacterial growth factor or cytokine.
Insights
Micrococcus luteus secretes a resuscitation-promoting factor (Rpf) that stimulates dormant cell growth. This protein enhances viable cell counts and promotes growth in various high G+C Gram-positive bacteria, including mycobacteria.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- Dormant bacterial cells pose challenges in culture and detection.
- Micrococcus luteus produces a factor that aids in the revival of non-growing cells.
- This factor, the resuscitation-promoting factor (Rpf), is a purified protein.
Purpose of the Study:
- To characterize the Rpf protein from Micrococcus luteus.
- To investigate the effects of Rpf on dormant and growing bacterial cells.
- To explore the distribution and potential applications of Rpf and its related genes in other bacteria.
Main Methods:
- Purification of the resuscitation-promoting factor (Rpf) to homogeneity.
- Assaying Rpf's effect on viable cell counts of dormant M. luteus.
- Testing Rpf's growth-promoting activity on various bacterial species, including mycobacteria.
- Analyzing genome sequences and hybridization data for Rpf-like genes in Gram-positive bacteria.
Main Results:
- Rpf, a protein, promotes resuscitation and growth of dormant M. luteus cells at picomolar concentrations.
- Rpf significantly increases viable cell counts (over 100-fold) and stimulates growth.
- Rpf also stimulates the growth of several high G+C Gram-positive bacteria, notably mycobacteria (M. avium, M. bovis, M. kansasii, M. smegmatis, M. tuberculosis).
- Genes encoding Rpf homologs are widespread in high G+C Gram-positive bacteria, including Mycobacterium, Corynebacterium, and Streptomyces species.
Conclusions:
- Rpf is a potent bacterial growth factor with autocrine and paracrine functions.
- The widespread distribution of Rpf-like genes suggests conserved mechanisms for bacterial resuscitation and growth.
- Mycobacterial Rpf homologs represent potential targets for pathogen detection and control strategies.