Showing papers by "Erwin A. Galinski published in 1991"

Isolation and structure determination of a novel compatible solute from the moderately halophilic purple sulfur bacterium Ectothiorhodospira marismortui

Abstract: The halophilic phototrophic bacterium Ectothiorhodospira marismortui produces three organic osmolytes to counterbalance the osmotic pressure of the surrounding medium: glycine betaine, sucrose, and a novel compound. This new compound, which accounts for approximately 30% of the cells' compatible solutes, was isolated and identified by mass spectrometry and nuclear magnetic resonance. It was characterized as Nα-carbamoyl-l-glutamine 1-amide, an unusual amino acid derivative with no previous reference in the chemical literature. The relatively high cytoplasmic concentration of this compound (∼ 0.5 M) observed at all growth conditions suggests that it may serve a vital function as an osmoticum and/or protectant for Ectothiorhodospira marismortui in a saline environment.

Halophily, Taxonomy, Phylogeny and Nomenclature

Abstract: On a first view there is apparently little correlation between taxonomy and halophily The distribution of different compatible solutes in the eubacterial phyla Proteobacteria and Firmacutes follows a pattern, however, that at least follows certain regularities: (1) All eubacteria that gain energy from photosynthesis or respiration and are capable of haloadaptation are able to accumulate and/or synthesize compatible solutes (2) When a eubacterium can grow in a non-complex medium, it usually can synthesize ectoine Growth on yeast extract does not necessarily exclude ectoine synthesis (3) Extreme halophily in eubacteria is always accompanied by glycine betaine synthesis The complete synthesis of glycine betaine from CO2 or simple carbon compounds has only been proven for cyanobacteria, Ectothiorhodospiraceae and Actinopolyspora halophila (4) A not yet identified compound “Y” occurs preferably in Firmacutes; Bacillus species accumulate and synthesize proline and glutamate as compatible solutes

Intracellular salt and solute concentrations in Ectothiorhodospira marismortui : glycine betaine and Nα-carbamoyl glutamineamide as osmotic solutes

Abstract: Ectothiorhodospira marismortui, a moderately halophilic purple sulfur bacterium from a hypersaline sulfur spring, contains glycine betaine and Nα-carbamoyl glutamineamide (CGA) as the main intracellular osmotic solutes, with sucrose as a minor component. The concentration of glycine betaine was found to increase with increasing salt concentration of the medium, from 0.47 M to 1.29 M in cells grown from 0.85 to 2.56 M NaCl, while the estimated CGA concentration rose from about 0.2 M to 0.5 M. The concentration of sucrose remained constant at a value of around 0.05 M. Intracellular sodium and potassium concentrations were relatively low (around 0.5 and 0.3 M, respectively, at an external NaCl concentration of 1.8 M). The concentration of the novel compound Nα-carbamoyl glutamineamide was enhanced when l-glutamine was added to the growth medium, suggesting that glutamine served as a precursor for the synthesis of the compound.

Novel Compatible Solutes and Their Potential Application as Stabilizers in Enzyme Technology

Abstract: A novel class of compatible solutes, the “ectoines”, are evidently widespread in nature and seem to serve both osmotic and enzyme protective functions. The ectoines are characterized by the following structural features: - hydrogenated pyrimidine carboxylic acid in the conformation of a half chair, - delocalized π-bonding (and positive charge) between nitrogen 1 and 3, - permanent zwitterionic properties at physiological pH. Using an unidentified actinomycete (strain A5-1) as a producer strain and a chemical extraction method followed by chromatographic purification procedures we are presently able to gain approximately 10 g of ectoines from 100 g of bacterial dry mass. A preliminary investigation has shown that ectoines exert a remarkable protective effect on a number of labile enzymes, which in many cases surpasses that of betaine.