Protein Secreted By Bacillus Subtilis ATCC 21332 In The Presence Of Allium Sativum

Many studies have reported that the primary activity of most inhibitors of bacterial function is to modulate
transcription processes at much lower concentrations than that required for antibiosis. Therefore, the bacteria
might be produced and secreted more proteins in the mild stress surroundings (e.g. in the presence of low doses
of antimicrobial agents) than in the normal environment. However, not much is known about unexpected ability
of natural antimicrobial compounds at low concentration to become a signaling agent that capable to modulate
biological functions in bacteria. Thus, this study aims to explore the potential of natural antimicrobial compound
(Allium sativum) at sub-minimal inhibitory concentration (sub-MIC) in regulating proteins production by
Bacillus subtilis ATCC 21332. The Minimum Inhibition Concentration (MIC) of A. sativum on B. subtilis
resulting 14.29% was determined by microdilution assay. The bacteria cells were further exposed to A. sativum
at sub-MIC (0.05 x MIC) in fermentation process. SDS-PAGE profile showed that two protein bands with
approximate size of 51.36 kD and 9.74 kD were produced for the bacteria treated with A. sativum. LC-MS/MS
analysis identified six possible proteins from the two bands expressed in mild stress condition. The proteins
exhibited antimicrobial activity towards several Gram-positive and Gram-negative bacteria. Hence, B. subtilis
ATCC 21332 in mild stress condition with the presence of 0.05 x MIC A. sativum could regulate bioactive
proteins production. Copyright © AJBCPS, all rights reserved.
Keywords: Bacillus subtilis ATCC 21332, Allium sativum, proteins, sub-MIC, antimicrobial agent,
transcription