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INCREASE IN BACTERIOPHAGE AND GELATINASE CONCENTRATION IN CULTURES OF BACILLUS MEGATHERIUM
1Laboratories of The Rockefeller Institute for Medical Research, Princeton, New Jersey.
Abstract:
1. The increase in bacteria, phage concentration, and gelatinase concentration in cultures of B. megatherium has been determined. 2. With lysogenic cultures the phage concentration, gelatinase concentration, and bacteria concentration increase logarithmically at first. The phage and gelatinase concentration then decrease while the bacteria concentration increases to a maximum. 3. The results are the same with sensitive cultures if the ratio of phage to bacteria is small. If the ratio of phage to bacteria is large phage, gelatinase, and bacteria concentration all increase at first and then decrease. The maximum rate of increase coincides approximately with the maximum rate of oxygen consumption of the culture. 4. 60-90 per cent of the phage is free from the cells. 5. The amount of phage produced is determined by the combined phage and not by the total phage. 6. Phage is produced during growth of the cells and not during lysis. 7. In a very narrow range of pH near 5.55 no increase in bacteria occurs but large increases in phage may be obtained.
Insights
Bacteriophage (phage) and gelatinase concentrations increase with Bacillus megatherium bacteria, especially under specific pH conditions. Phage production occurs during bacterial growth, not lysis, with most phage released from cells.
Area of Science:
- Microbiology
- Bacteriology
- Virology
Background:
- Bacillus megatherium is a common soil bacterium.
- Bacteriophages (phages) are viruses that infect bacteria.
- Lysogenic cultures contain integrated phage DNA.
Purpose of the Study:
- To determine the concentration changes of bacteria, phage, and gelatinase in B. megatherium cultures.
- To investigate the dynamics of phage and gelatinase production in relation to bacterial growth and lysis.
Main Methods:
- Culturing B. megatherium under various conditions.
- Measuring concentrations of bacteria, phage, and gelatinase over time.
- Monitoring oxygen consumption and pH levels.
Main Results:
- In lysogenic cultures, bacteria, phage, and gelatinase initially increase logarithmically, followed by a decrease in phage and gelatinase as bacteria reach maximum levels.
- In sensitive cultures, low phage-to-bacteria ratios mirror lysogenic dynamics; high ratios lead to initial increases in all components before decreasing.
- Maximum growth rates correlate with peak oxygen consumption.
- 60-90% of phage is cell-free.
- Phage production is linked to combined phage levels and occurs during bacterial growth.
- A narrow pH range (around 5.55) inhibits bacterial growth but promotes significant phage increase.
Conclusions:
- Bacterial growth, phage concentration, and gelatinase production are interdependent and influenced by phage-to-bacteria ratios and environmental factors like pH.
- Phage replication dynamics are complex, occurring during bacterial growth and influenced by the amount of intracellular phage.
- Optimal conditions for phage production can be achieved even when bacterial growth is suppressed.
