About this Research Topic
From its very beginning, life has flourished in almost all imaginable environments, a number of them encompassing truly harsh physical and chemical conditions that once were thought to preclude the existence of living organisms. In this line, the term "extremophile" - from the Latin "extremus" for extreme and the Greek "philos" for love - refers to those organisms, belonging to all domains of life (Archaea, Bacteria and Eukarya), in which unique physiologies are present to cope with the challenges posed by extreme habitats. These include extreme pH values and temperatures, high salinity and pressure, desiccation, low nutrient availability, high UV radiation and even the presence of toxicants such as metal(loid)s that can poison the cell metabolism, among others. It is worth noting that a number of these harsh conditions may apply at once so that bacteria able to withstand them are known as polyextremophiles.
Regardless of the growth conditions, all polyextremophiles were selected for survival in a great variety of niches, thus ensuring such an evolutionary success which results in an extraordinary diversity of microorganisms. In particular, if water is really essential for life, then a number of physical limitations for it to take place are apparent. Water remains liquid within certain limits of temperature and pressure so that organisms living at extreme temperatures (< 0°C and > 100°C) are represented mainly by Archaea and Bacteria.
Since their discovery, research on extremophiles has gained strength, not only because of the interest in defining their lifestyle, physiology and adaptation to hostile environments, but also for exploring their biotechnological potentials and even identify bacterial model systems for life in other planets (astro- or exo-microbiology).
Although many species from all kind of extreme environments have been isolated and taxonomically described, very little is known about the molecular strategies that allow them to grow in these conditions. Here we propose an Interdisciplinary Research Topic that aims to address this issue by using multidisciplinary approaches for integrating data from biochemical, genomic, transcriptomic, proteomic, bioinformatics and evolutionary aspects of polyextremophilic Archaea and Bacteria. Finally, the various and unique physiologies that have evolved to meet the challenges posed by the above described harsh conditions, strongly suggest that life could exist in outer space.
Keywords: Extremophiles, Environmental stress, molecular mechanisms, adaptive evolution, resistance.
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.