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Germination of the decoated spores of Bacillus megaterium
Abstract:
Decoated spores of Bacillus megaterium ATCC 12872 were prepared by extracting the inner coat components with an alkaline solution containing sodium dodecyl sulfate and dithiothreitol (SDS-DTT) from outer coat-deficient mutant spores, which were produced from one of the mutants isolated and named MAE-05 by us. The decoated mutant spores germinated as well as the intact spores of the mutant and the parent, indicating that the outer and inner spore cats cannot be essential structures for the initiation of germination. When the SDS-DTT-treated MAE-05 spores were converted to H-spores by incubation in citrate-phosphate buffer (pH 3.5) at 30 C for 3 hr, they lost their germinability by glucose and KNO3. Ca-spores, prepared by treating H-spores with 10 mM calcium acetate at 37 C for 60 min, regained the germinability. Experiments on the interaction of 45Ca with the cortex and the inner membrane isolated from H-spores suggested that the calcium present in the inner membrane might be related to germinability.
Insights
Bacillus megaterium spore coats are not essential for germination initiation. Calcium in the inner membrane appears crucial for spore germination, as its removal inhibits and re-addition restores germinability.
Area of Science:
- Microbiology
- Bacterial spore germination
- Cellular structures
Background:
- Bacillus megaterium spore coats play roles in protection and germination.
- Previous studies have focused on the role of outer spore coats.
Purpose of the Study:
- To investigate the necessity of Bacillus megaterium spore coats for germination.
- To elucidate the role of calcium in spore germination.
Main Methods:
- Preparation of decoated Bacillus megaterium spores using SDS-DTT treatment.
- Induction of H-spores and Ca-spores to assess germinability.
- Analysis of 45Ca interaction with spore components.
Main Results:
- Decoated spores germinated similarly to intact spores, indicating spore coats are non-essential for germination initiation.
- H-spores (lacking calcium) lost germinability, which was restored upon Ca-spore formation.
- Calcium in the inner membrane was implicated in spore germinability.
Conclusions:
- Outer and inner spore coats are not essential for Bacillus megaterium spore germination.
- Calcium ions, particularly within the inner membrane, are critical for initiating spore germination.