Page 405 - AWSAR 2.0
P. 405

 Fig. 1. Graphical representation of morphological transition post sublethal SPC.
environments such as WWTPs, the current situation becomes exacerbated to many folds and thus calls for innovative methods, which are at par to counter the microbial response to the treatment. Hence, we challenged our process to check whether if it could pose a threat in the future by incurring microbes to
flare up AMR. We stopped SPC
before the system achieved full
disinfection, deliberately letting
some microbes to ‘escape’ the
treatment, rightfully called the
sublethal SPC. These microbes
were exposed to many such
sublethal SPC cycles to induce
evolution against the pressure
of SPC. Neither did they gain
SPC process resistance nor did
they acquire resistance against
an array of antibiotics used
in the study. Interestingly, the
superiority of SPC resulted in
an overall loss of AMR. During
this fascinating project, we were
sure that the microbial SOS
system might be working very
hard to fight off the effect of SPC. We observed a decreasing shift in the microbial colony size with the rise in treatment time. On validating
this observation under electron microscopy, we serendipitously discovered a significant change in the morphology of Salmonella typhimurium, converting them from original rod shape into a spherical morphotype, called as spheroplast-like structures. These
are cell membrane–defective structures, thus making sense in the loss of AMR after SPC treatment. However, these structures can revert to their original forms when we remove the oxidative stress and thereby gain back the intrinsic AMR. A graphical representation of the overall process is shown in Fig. 1. Since AMR is not a deciding factor, which makes a microbe ‘bad’, we also looked into the change in virulence factors after exposing the bug to a number of sublethal SPC cycles. In short, these molecular machines help microbes to invade and evade a host. We found that the
invasion potential of microbes subjected to sublethal SPC cycles decreased drastically. We believed that the morphological transition
Mr. Habeeb Rahman A.P. || 381
   The energy contributed to the surface of the NPs leads to jumping of electrons from their designated place called ‘valance band’ to an unstable state called ‘conduction band’. This reaction in the proximity of water molecules yields highly baneful reactive oxygen species (ROS) such as hydroxyl radicals (•OH), superoxide anions (O2•), hydrogen peroxide (H2O2), etc.
  







































































   403   404   405   406   407