Ultraviolet radiation-mediated damage and resilience strategies of Antarctic microbes with special emphasis on their potential biotechnological applications
摘要
Multiple stress factors of the Antarctic arid climate like cold, low nutrients, heavy metal, acidification, desiccation, and ultraviolet (UV) radiation have made it an inappropriate and unfavorable ecoplace for any living individual to survive. Antarctic microbes have evolved remarkable adaptive mechanisms to withstand multiple stressors, particularly UV radiation. Due to ozone depletion, the incoming UV-ray is responsible for macromolecule distortion, formation of cyclobutane pyrimidine dimers, pyrimidine–pyrimidone (6–4) photoproducts, reactive oxygen species generation, pigment bleaching, lipid peroxidation, etc. that affect metabolism, energy production, anabolism, and normal cellular function. Microbes produce UV-absorbing pigments, develop efficient DNA repair systems, and antioxidant enzymes that protect themselves from UV stress. These fascinating adaptations help them survive and contribute to the resilience and ecological balance in the extreme Antarctic environment. Antarctic bacteria, Hymenobacter metalli and Pseudomonas extremaustralis, could tolerate up to 12.6 J cm−2 and 9.0 J cm−2 of UV doses, respectively. Microorganisms like Alteromonas stellipolaris, Streptomyces griseus, and Lysobacter oligotrophicus, have evolved to produce melanin, which exhibits a range of beneficial properties, including photoprotection, antioxidant, and antimicrobial activity. Additively, microbes can generate spores, produce mycosporine-like amino acids (MAAs) and bioactive extracellular polymeric substances that provide an extracellular layer of protection, shielding the cells from UV damage. UV-resistant microbial bioactive substances are valuable natural compounds with potential therapeutic and cosmetic benefits which are highly consumed in the food, drug, textile, and pharmaceutical industries due to their wide range of biotechnological efficiency. In future, more refinement of these products could replace the chemical derivatives that are being used robustly in recent years.
Graphical abstract