Osmotic adaptation of moderately halophilic methanogenic Archaeobacteria,and detection of cytosolicN,N-dimethylglycine |
| |
Authors: | J A G F Menaia J C Duarte D R Boone |
| |
Institution: | (1) Department of Environmental Science and Engineering, Oregon Graduate Institute, 19600 N. W. von Neumann Dr., 97006-1999 Beaverton, Oregon, USA;(2) Department of Chemical and Biological Sciences, Oregon Graduate Institute, 19600 N. W. von Neumann Dr., 97006-1999 Beaverton, Oregon, USA;(3) Department of Technology of Chemical Industries, National Laboratory of Engineering and Industrial Technology, Estrada Palmeiras, Queluz de Baixo, 2745 Queluz, (Portugal) |
| |
Abstract: | Methanohalophilus mahii SLP andMethanohalophilus halophilus Z-7982, two closely-related, moderately halophilic, methylotrophic methanogens, were tested for their adaptation to saline conditions. They grew in a wider range of salinities than previously reported, in a defined medium with as little as 0.1 M NaCl, and with a high as 4.0 M NaCl forM. halophilus and 4.5 M NaCl forM. mahii. Fastest growth occurred with 1.5 M NaCl forM. mahii and 1.0 M NaCl forM. halophilus. M. mahii also grew in media in which NaCl was replaced by sucrose or KCl as osmolytes up to the osmolal equivalent of 2 and 2.5 M NaCl (these media contained other sodium salts totaling about 0.1 M Na+). In media with either sucrose of KCl replacing NaCl,M. mahii grew fastest at osmolalities approximately equiosmolal to 1 M NaCl.M. mahii not only grew well at a wide range of osmosities, it also tolerated rapid shifts in osmolality. Cells subjected to a rapid 10-fold hypertonic shift resumed growth without a prolonged lag. When cells were subjected to a rapid 10-fold hypotonic shift, 90% of cells lysed, but the remaineder continued to swell with little further lysis during the next 45 min. Surviving cells resumed growth.Methanohalophilus strains grown in defined medium had low cytosolic Na+ concentrations; K+ concentrations were as high as 0.35 M. Organic osmotica in the cytosol include glycine betaine and larger amounts of N,N-dimethylglycine. |
| |
Keywords: | N N-dimethylglycine methanogens compatible solutes halophilic bacteria osmotic adaptation |
本文献已被 SpringerLink 等数据库收录! |
|