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Influence of urea on the growth of T-strain mycoplasmas
Abstract:
T-strain mycoplasmas require urea for propagation, but urea metabolism also occurs in nonpropagating viable cultures. Ammonia results from this metabolism and alkalinizes the medium. Ammonium ions and an alkaline pH both inhibit the multiplication of T strains and reduce the viability of T strains in broth. These toxic effects of urea metabolism currently limit the growth of T strains in broth. Stock T-strain cultures are optimally maintained in continuous culture if the routine medium at pH 6.0 is supplemented with 0.05% urea and 0.002% phenol red, but an incubation temperature of 30 C is preferable to 37 C for subculture at 24-hr intervals.
Insights
T-strain mycoplasmas need urea to grow, but their metabolism produces ammonia, which inhibits their multiplication. Optimizing T-strain culture involves adding urea and phenol red to the medium at pH 6.0 and incubating at 30°C.
Area of Science:
- Microbiology
- Bacteriology
Background:
- T-strain mycoplasmas are microorganisms that require urea for propagation.
- Urea metabolism in T-strain mycoplasmas produces ammonia, leading to medium alkalinization.
- Ammonia and alkaline pH inhibit T-strain multiplication and reduce viability.
Purpose of the Study:
- To investigate the effects of urea metabolism on T-strain mycoplasma growth.
- To determine optimal conditions for maintaining T-strain cultures.
Main Methods:
- Culturing T-strain mycoplasmas in media with varying urea concentrations.
- Monitoring ammonia production and pH changes.
- Assessing T-strain viability and multiplication rates.
- Evaluating different incubation temperatures and media supplements.
Main Results:
- Urea metabolism generates ammonia, causing significant medium alkalinization.
- Elevated ammonia levels and alkaline pH were found to be toxic to T-strain mycoplasmas.
- Optimal maintenance of stock T-strain cultures was achieved in continuous culture at pH 6.0 with 0.05% urea and 0.002% phenol red.
- An incubation temperature of 30°C was found to be preferable to 37°C for subculture at 24-hour intervals.
Conclusions:
- The toxic effects of ammonia and alkaline pH resulting from urea metabolism currently limit T-strain growth in broth.
- Specific supplementation and controlled conditions (pH 6.0, 30°C) are crucial for optimal T-strain propagation and stock culture maintenance.