Molecular and Physiological Adaptations to Low Temperature in Strains Isolated from Soda Lakes with Different Temperature Regimes.

The genus comprises sulfur-oxidizing bacteria thriving in soda lakes at high pH and salinity. Depending on the geographical location and the season, these lakes can strongly vary in temperature. To obtain a comprehensive understanding of the molecular and physiological adaptations to low temperature, we compared the responses of two strains to low (10°C) and high (30°C) temperatures.

Exploiting Substrate Promiscuity of Ectoine Hydroxylase for Regio- and Stereoselective Modification of Homoectoine.

Extant enzymes are not only highly efficient biocatalysts for a single, or a group of chemically closely related substrates but often have retained, as a mark of their evolutionary history, a certain degree of substrate ambiguity. We have exploited the substrate ambiguity of the ectoine hydroxylase (EctD), a member of the non-heme Fe(II)-containing and 2-oxoglutarate-dependent dioxygenase superfamily, for such a task. Naturally, the EctD enzyme performs a precise regio- and stereoselective hydroxylation of the ubiquitous stress protectant and chemical chaperone ectoine (possessing a six-membered pyrimidine ring structure) to yield -5-hydroxyectoine.

Hydroxyl radical scavenging of the compatible solute ectoine generates two N-acetimides.

Living cells employ various defence mechanisms against reactive oxygen species and free radicals. Besides protecting enzymes such as superoxide dismutase, catalase and peroxidase, non-enzymatic antioxidant molecules also play an important role as radical scavengers. Within bacteria the amino acid derivative ectoine (2-methyl-3,4,5,6-tetrahydropyrimidine-4-carboxylate) is the most abundant compatible solute and stress protectant.

Homoectoine Protects Against Colitis by Preventing a Claudin Switch in Epithelial Tight Junctions.

Background: Inflammatory bowel diseases (IBD) are multifactorial disorders affecting millions of people worldwide with alarmingly increasing incidences every year. Dysfunction of the intestinal epithelial barrier is associated with IBD pathogenesis, and therapies include anti-inflammatory drugs that enhance intestinal barrier function. However, these drugs often have adverse side effects thus warranting the search for alternatives.