Analysis of the germination proteins in Alicyclobacillus acidoterrestris spores subjected to external factors.

Abstract

The presence of Alicyclobacillus acidoterrestris, a thermoacidophilic and spore-forming bacterium, in pasteurized acidic juices poses a serious problem for the processing industry. Therefore, the use of other more effective techniques, such as high hydrostatic pressure (HHP) and supercritical carbon dioxide (SCCD), is considered for preserving juices in order to inactivate these bacteria, while reducing the loss of nutrients and sensory quality of juices. On the other hand, HHP and SCCD when combined with a moderately elevated temperature can induce germination of bacterial spores, making them more vulnerable to inactivation. The spore germination can be also induced by nutrients, such as L-alanine or a mixture of asparagine, glucose, fructose and potassium ions (AGFK). The aim of this work was to determine whether applying activating agents: HHP, SCCD and nutrient germinants (L-alanine and the AGFK mixture), could influence the number of spores which start to germinate and how this affects the proteins involved in the spore germination. SDS-PAGE was used to resolve proteins isolated from the A. acidoterrestris spores. The results that were obtained indicate that the germination of A. acidoterrestris spores treated with HHP, SCCD and nutrient germinants reflect the number of spores which start to germinate. The SDS-PAGE data indicated changes in the level of selected proteins occurring when subjected to the germination activating factors as well as noticeable differences in those proteins' molecular weights.