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[Variability of Bacillus thuringiensis under various growth conditions]
Mikrobiologiia
|May 1, 1984
Summary
Chemostat cultivation of Bacillus thuringiensis subsp. galleriae 69-6 dramatically increased S-variants and induced temperate phage h-mutants, impacting spore formation. Growth conditions significantly alter bacterial population dynamics and phage behavior.
Area of Science:
- Microbiology
- Bacteriology
- Virology
Context:
- Lysogenic Bacillus thuringiensis subsp. galleriae 69-6 cultures exhibit distinct R-form and S-form colony variants under different growth conditions.
- Batch cultivation favors R-form colonies (93-99%) with high spore-forming capacity (99%), while S-form colonies are rare (ca. 1%) with low spore formation (8%).
Purpose:
- To investigate the influence of batch versus chemostat cultivation on the population dynamics of Bacillus thuringiensis subsp. galleriae 69-6.
- To determine the emergence and characteristics of temperate phage h-mutants under varying growth-limiting conditions in chemostat cultures.
Summary:
- Chemostat cultivation led to a significant shift towards S-variants (up to 99%), with their numbers increasing with growth rate and duration.
- Temperate phage h-mutants, absent in batch cultures, appeared in chemostat cultures, with titers up to 10(8) particles/ml under yeast extract limitation.
- Phage titers did not correlate with R/S-form ratios, and phosphorus limitation increased S-forms while inhibiting spontaneous phage induction.
Impact:
- Chemostat conditions profoundly alter bacterial morphology and phage interactions, revealing environmental influences on microbial populations.
- The study highlights the emergence of specific phage variants under controlled nutrient limitations, impacting bacterial culture stability and characteristics.