Project description:If life exists on Mars, it would face several challenges including the presence of perchlorates, which destabilize biomacromolecules by inducing chaotropic stress. However, little is known about perchlorate toxicity for microorganism on the cellular level. Here we present a proteomic investigation on the perchlorate-specific stress responses of the halotolerant yeast Debaryomyces hansenii and compare these to generally known salt stress adaptations. We found that the responses to NaCl and NaClO4-induced stresses share many common metabolic features, e.g., signaling pathways, elevated energy metabolism, or osmolyte biosynthesis. However, several new perchlorate-specific stress responses could be identified, such as protein glycosylation and cell wall remodulations, presumably in order to stabilize protein structures and the cell envelope. These stress responses would also be relevant for life on Mars, which - given the environmental conditions - likely developed chaotropic defense strategies such as stabilized confirmations of biomacromolecules and the formation of cell clusters.
Project description:We found that the fungus, Debaryomyces hansenii (D. hansenii), is enriched in inflamed intestinal tissue from patients of Crohn's disease and its administration to mice impairs colonic wound healing in multiple models of colonic injury and repair. To understand the mechanism, we isolated bone marrow derived macrophages from mice and stimulated them in vitro with a pure isolate of D. hansenii. Total RNA was isolated at multiple time points and assayed for transcriptomic analysis.
Project description:The mechanisms of cellular and molecular adaptation of fungi to salinity have been commonly drawn from halotolerant strains, although some exceptions in basidiomycete fungi can be found. These studies have been conducted in settings where cells are subjected to stress, either hypo or hyperosmotic, which can be a confounding factor in describing physiological mechanisms related to salinity. Here, we have studied transcriptomic changes in Aspergillus sydowii, a halophilic species, when growing in three different salinity conditions (No salt, 0.5M and 2.0M NaCl). In this fungus salinity related responses occur under high salinity (2.0M NaCl) and not when cultured under optimal conditions (0.5M NaCl), suggesting that in this species, most of the mechanisms described for halophilic growth are a consequence of saline stress response and not an adaptation to saline conditions.
Project description:Phytate (myo-inositol hexakisphosphate) is the primary storage form of phosphate in seeds and legumes (Reddy et al., 1982). Phytases are phosphatases that hydrolyze phytate to less phosphorylated myo-inositol derivatives and inorganic phosphate. The crystal structure of phytase from Debaryomyces castellii has been determined at 2.3 A resolution. The crystals belonged to space group P6(5)22, with unit-cell parameters a = 121.65, c = 332.24 A. The structure was solved by molecular replacement and refined to a final R factor of 15.7% (R(free) = 20.9%). The final model consists of a dimer (with two monomers of 458 residues), five NAG molecules and 628 water molecules.
Project description:Here, we treated Escherichia coli strain TO114 expressing a halotolerant cyanobacterium Halothece sp. PCC7418-derived NhaC Na+/H+ antiporter (H2569) with salt stress (0.4 M NaCl) and performed RNA sequencing analysis.
