Water and temperature relations of soil Actinobacteria


Autoria(s): Stevenson, Andrew; Hallsworth, John E.
Data(s)

01/12/2014

Resumo

<p>Actinobacteria perform essential functions within soils, and are dependent on available water to do so. We determined the water-activity (a<sub>w</sub>) limits for cell division of <em>S</em><em>treptomyces albidoflavus</em>, <em>S</em><em>treptomyces rectiviolaceus</em>, <em>M</em><em>icromonospora grisea</em> and <em>M</em><em>icromonospora</em> (JCM 3050) over a range of temperatures, using culture media supplemented with a biologically permissive solute (glycerol). Each species grew optimally at 0.998 a<sub>w</sub> (control; no added glycerol) and growth rates were near-optimal in the range 0.971–0.974 (1 M glycerol) at permissive temperatures. Each was capable of cell division at 0.916–0.924 a<sub>w</sub> (2 M glycerol), but only <em>S</em><em>. albidoflavus</em> grew at 0.895 or 0.897 a<sub>w</sub> (3 M glycerol, at 30 and 37°C respectively). For <em>S</em><em>. albidoflavus</em>, however, no growth occurred on media at ≤ 0.870 (4 M glycerol) during the 40-day assessment period, regardless of temperature, and a theoretical limit of 0.877 a<sub>w</sub> was derived by extrapolation of growth curves. This level of solute tolerance is high for non-halophilic bacteria, but is consistent with reported limits for the growth and metabolic activities of soil microbes. The limit, within the range 0.895–0.870 a<sub>w</sub>, is very much inferior to those for obligately halophilic bacteria and extremely halophilic or xerophilic fungi, and is inconsistent with earlier reports of cell division at 0.500 a<sub>w</sub>. These findings are discussed in relation to planetary protection policy for space exploration and the microbiology of arid soils.</p>

Identificador

http://pure.qub.ac.uk/portal/en/publications/water-and-temperature-relations-of-soil-actinobacteria(3675c513-2339-466d-962a-4ffe70d1cac2).html

http://dx.doi.org/10.1111/1758-2229.12199

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Stevenson , A & Hallsworth , J E 2014 , ' Water and temperature relations of soil Actinobacteria ' Environmental Microbiology Reports , vol 6 , no. 6 , pp. 744-55 . DOI: 10.1111/1758-2229.12199

Tipo

article