Cellular localization of a Hsp90 homologue in Porphyromonas gingivalis

We previously reported an association between elevated serum antibody titers to the 90-kDa human heat shock protein (Hsp90), periodontal health and colonization by Porphyromonas gingivalis. In this study, we examined the cellular localization of the Hsp90 homologue of P. gingivalis. Cultures of P. gingivalis were heat-stressed (45 degrees C) and examined for localization of the Hsp90 homologue. Heat stress induced a 4-5-fold increase in anti-Hsp90 antibody reactivity over that of the unstressed controls. Western blot analysis revealed two bands (44 and 68 kDa) that reacted with anti-Hsp90 antibodies. The 68-kDa band was heat-inducible, while the 44-kDa band was not. Immunogold staining revealed that the Hsp90 homologue localized principally to the membrane and extracellular vesicles. Subcellular fractionation confirmed that the Hsp90 homologue was primarily membrane-associated.     

Ecophysiology and polymorphism of the unicellular extremely natronophilic cyanobacterium <Emphasis Type="Italic">Euhalothece</Emphasis> sp. Z-M001 from Lake Magadi

Strain Z-M001 of a unicellular cyanobacterium, assigned by analysis of the 16S rRNA gene sequence to the phylogenetic group of the generic level Euhalothece, was isolated from soda Lake Magadi. It was shown that strain Z-M001, unlike all other known cultured and uncultured organisms of the Euhalothece group, is extremely natronophilic, and it was named accordingly “Euhalothece natronophila”. In its ecophysiological characteristics, it is comparable to extremely alkaliphilic organotrophic natronobacteria, which is essential for soda ecosystems, because cyanobacteria belong to primary producers. E. natronophila exhibits considerable morphological variability depending on the concentration of carbonates in the medium. The polymorphism of “ E. natronophila” is primarily connected to limitation by utilizable forms of carbon.     

Environmental adaptation factors of two yeasts isolated from the leachate of a uranium mineral heap

Mycosporine-like amino acids (MAAs) were extracted from a unicellular cyanobacterium (Euhalothece sp.) isolated from a gypsum crust on the bottom of a hypersaline saltern pond in Eilat, Israel. When grown at high light intensities, this isolate contained high concentrations of two MAAs, one showing maximum optical density at 331 nm and one at 362 nm. The compound absorbing at 331 nm was purified by preparative high performance liquid chromatography, and its structure was elucidated by one-dimensional ((1)H and (13)C) and two-dimensional nuclear magnetic resonance, mass spectrometry and amino acid analysis, and identified as mycosporine-2-glycine. This is the first report of mycosporine-2-glycine in cyanobacteria.     

Structure of euhalothece-362, a novel red-shifted mycosporine-like amino acid, from a halophilic cyanobacterium (Euhalothece sp.)

The unicellular cyanobacterium Euhalothece sp. strain LK-1, isolated from a gypsum crust on the bottom of a hypersaline saltern pond in Eilat, Israel, contains high concentrations of two mycosporine-like amino acids with maximum absorbance at 331 and 362 nm when grown at high light intensities. The 331 nm-absorbing compound has previously been identified as mycosporine-2-glycine. Here, we confirm this identification and document the elucidation of the structure of the 362 nm absorbing compound ('euhalothece-362'), using liquid chromatography/mass spectrometry combined with other techniques, as a novel compound, 2-(E)-3-(E)-2,3-dihydroxyprop-1-enylimino-mycosporine-alanine.