The malic enzyme from Halobacterium cutirubrum requires monovalent cations for both activation and stabilization. NaCl, the best stabilizer, is ineffective as activator; NH(4)Cl, the best activator, is a poor stabilizer. These results support the idea that the roles of salts in both processes are different.

A group of moderately halophilic bacteria able to degrade aromatic organic compounds contaminating hypersaline habitats in southern Spain have been isolated and characterized. The taxonomic position of these strains was determined using phenotypic, phylogenetic and genotypic methods. The G + C content of their DNA ranged from 61.0 to 62.9 mol%. DNA-DNA hybridization studies showed that they con...

The nicotinamide adenine dinucleotide phosphate-specific isocitrate dehydrogenase of Halobacterium cutirubrum is rapidly inactivated at low NaCl levels. As much as 75% of the initial activity can be restored by dialyzing the inactive enzyme against 4 m NaCl. A mixture of 4 mm isocitrate and 10 mm MnCl(2) gives the same protection as 4 m NaCl but does not replace the NaCl requirement for reactiv...

A Gram-negative bacterium, designated LA31B(T), was isolated from water collected from a hypersaline lagoon on Laysan Atoll in the north-western Hawaiian Islands. Single cells of LA31B(T) were slightly curved but became helical as their length increased. Preliminary characterization based on 16S rRNA gene sequence analysis showed that LA31B(T) shared 96.0 % identity with an Arcobacter sp. isola...

Halobacterium salinarum is a bioenergetically flexible, halophilic microorganism that can generate energy by respiration, photosynthesis, and the fermentation of arginine. In a previous study, using a genome-scale metabolic model, we have shown that the archaeon unexpectedly degrades essential amino acids under aerobic conditions, a behavior that can lead to the termination of growth earlier th...

A moderately halophilic, Gram-positive coccus, designated strain W24(T), was isolated from saline soil in Qinghai province, China. The isolate was able to grow at salinities of 0-24 % (w/v) NaCl (optimally at 8 %, w/v), at pH 5.5-9.0 (optimally at pH 7.5) and at 8-43 degrees C (optimally at 28 degrees C). The genomic DNA G+C content of strain W24(T) was 45.8 mol%. The predominant isoprenoid qui...

Compatible solutes like ectoine and its derivatives are deployed by halophile organisms as osmolytes to sustain the high salt concentration in the environment. This work investigates the relation of the thermodynamic properties of compatible solutes and their impact as osmolytes. The ectoines considered in this work are ectoine, hydroxyectoine, and homoectoine. Besides solution densities (15-45...

Hypersaline environments are important for both surface extension and ecological significance. As all other ecosystems, they are impacted by pollution. However, little information is available on the biodegradation of organic pollutants by halophilic microorganisms in such environments. In addition, it is estimated that 5% of industrial effluents are saline and hypersaline. Conventional nonextr...