It is inferred that amino acids, such as alanine or valine, initially bind to the B-subunit of these receptors, thereby causing their activation 4, 8. These proteins are each composed of three subunits and can be triggered by several types of germinants including specific amino acids 4, 7. subtilis three GRs are well known - GerA, GerB and GerK.
As discussed throughout this thesis, the resistance properties of spores are mainly caused by their layered structure and the chemical composition of those various layers 2, 4 and the germination receptor proteins (GRs), located in the inner membrane (IM), facilitate spore germination 5, 6. Therefore, gaining a detailed knowledge of sporulation and spore germination is of utmost importance. However, empirical studies on spores, fail to reveal the mechanistic basis of the spore’s resistance to the generally deployed bacterial elimination methods 1– 3. This observation has challenged the food industries and the medical sector to extensively investigate both these processes to minimise microbiological risks by developing novel targeted strategies to eliminate spores. Sporulation and germination of genetically identical bacterial cells or spores have been extensively studied and shown to occur heterogeneously. Our findings also show that the different sporulation conditions and the maturation time of spores affect the expression of MalS-GFP and the germination behaviour of the spores. Thus the instantaneous increase in fluorescence of MalS-GFP may likely due to a change in the physical environment as the spore germination is triggered. Western blot analyses, however, indicate no increase in the levels of the MalS-GFP fusion protein during the first 15 minutes after the addition of the germinants.
Our results show an initial increase within the first 15 minutes of germination, followed by a drop and stabilization of the fluorescence throughout the spore ripening period. subtilis spore germination by investigating the dynamics of the fluorescence level of a MalS-GFP fusion protein using time-lapse fluorescence microscopy. The present study focuses on the synthesis of protein MalS during B. This leads to the formation of vegetative cells via germination and subsequent outgrowth. When environmental conditions become favourable, they can germinate as the germinant receptors located on the spore’s inner membrane get activated via germinant binding.
The spores remain in a dormant state for extended periods due to their highly resistant features. Spore forming bacteria of the orders Bacillales and Clostridiales play a major role in food spoilage and food-borne diseases.