Psychrophiles

• Published in: Annual Review of Earth and Planetary Sciences
• Main Authors: Siddiqui, KS, Williams, TJ, Wilkins, D, Yau, S, Allen, MA, Brown, MV, Lauro, FM, Cavicchioli, R
• Other Authors: Jeanloz, R
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Annual Reviews 2013
• Subjects: 14 Life Below Water; anzsrc-for: 0601 Biochemistry and Cell Biology; anzsrc-for: 0605 Microbiology; anzsrc-for: 060504 Microbial Ecology; anzsrc-for: 02 Physical Sciences; anzsrc-for: 04 Earth Sciences; Antarctic; Antarc*
• Online Access: http://hdl.handle.net/1959.4/unsworks_49977; https://doi.org/10.1146/annurev-earth-040610-133514

Psychrophilic (cold-adapted) microorganisms make a major contribution to the Earth’s biomass and perform critical roles in global biogeochemical cycles. The vast extent and environmental diversity of Earth’s cold biosphere has selected for equally diverse microbial assemblages that can include archaea, bacteria, eucarya and viruses. Molecular biology-based studies, and particularly DNA sequencing of whole environmental samples (metagenomics), has not only revealed the diversity of psychrophilic taxa, but revealed a capacity to perform a broad range of functions and microbial processes. Underpinning the important ecological roles of psychrophiles are exquisite mechanisms of physiological adaptation, involving specific cellular components (e.g. lipid membranes), genomic traits and patterns of global gene expression. Evolution has also selected for cold-active traits at the level of molecular adaptation, and enzymes from psychrophiles are characterized by specific structural, functional and stability properties. These characteristics of enzymes from psychrophiles not only manifest in efficient low temperature activity, but result in a flexible protein structure that enables biocatalysis in non-aqueous solvents, and provides the basis for significant enhancement of catalytic performance under a wide range of challenging conditions. In this review we examine the ecology of Antarctic psychrophiles, physiological adaptation of psychrophiles, and properties of cold-adapted proteins, and provide a view of how these characteristics inform studies of astrobiology.