Temperature range variants of Bacillus megaterium.

Area of Science:

• Microbiology
• Bacterial Genetics
• Thermophile Research

Background:

• Mesophilic Bacillus megaterium strains were investigated for thermophilic variants.
• Thermophilic variants were found at a low frequency (10^-8 - 10^-9).

Purpose of the Study:

• To isolate and characterize thermophilic variants of Bacillus megaterium.
• To investigate the genetic basis and properties of thermotolerance in these variants.

Main Methods:

• Isolation of thermophilic variants from mesophilic Bacillus megaterium.
• Curing of thermotolerance using acridine orange.
• Characterization of megacin production and activity.
• Phage sensitivity analysis.
• Arrhenius plot analysis for temperature characteristics.

Main Results:

• Facultatively and obligately thermophilic variants were successfully isolated.
• Thermotolerance was curable with acridine orange, suggesting plasmid involvement.
• A novel megacin produced by facultative thermophiles showed activity against mesophilic and obligate thermophilic strains.
• Taxonomic divergence was observed, but phage sensitivity and megacin spectrum indicated close relationships.
• Arrhenius plots confirmed temperature range variants with increased temperature characteristics at higher growth ranges.

Conclusions:

• The study suggests plasmid involvement in the thermotolerance of Bacillus megaterium variants.
• A novel bacteriocin (megacin) with a broad spectrum of activity was identified.
• Thermotolerance in Bacillus megaterium appears to be a phenomenon of temperature range variation rather than distinct species.