Evolutionarily Conserved Essential Genes from Arctic Bacteria: A Tool for Vaccination

Sir, Due to advancement in various molecular biological techniques, several indispensable evolutionarily conserved essential genes (genes that are necessary for viability of the living organisms) have been identified over the past decades among various groups of bacteria. Moreover, the amino acid sequences of some of these essential genes were highly conserved across various classes of bacteria such as thermophiles (heat-loving) and psychrophiles (cold-loving). However, some of the product of essential genes of psychrophiles have been adapted to the cold environments for millions to billions of years[+] thus making these bacteria temperature-sensitive (TS), reduced viability at higher temperatures. In accordance with the above mentioned facts, the human body temperature varies depending upon the body parts, temperature of the skin varies between 32 and 36°C whereas the body core is about 37-42°C. Over decades, attempts have been made to develop TS bacterial strains and viral strains, 9-12] yet bacterial strains were not adapted for human vaccination, for example, the TS version of Yersinia pestis and because of their reversion this strain was not further developed [13] Further, small numbers of TS bacterial strain vaccines (developed by chemical mutagenesis) were developed for veterinary use; but it is uncertain whether the TS nature is primary attenuating phenotype or merely a coincidental phenotype. [13] In the following work, Duplantis and colleagues have successfully transformed mesophilic pathogenic bacteria to a TS bacterial strain using essential genes from psychrophile and provide evidences for a successful vaccination strategy developed using such TS bacterial strain. The highlight, in the following work, is provided by the concept of using temperature adapted essential orthologue genes from psychrophile to develop the TS non-pathogenic version of bacterial strains.