Search results for " STRESS"
showing 10 items of 3936 documents
Rapid adaptation of signaling networks in the fungal pathogen Magnaporthe oryzae
2019
Abstract Background One fundamental question in biology is how the evolution of eukaryotic signaling networks has taken place. “Loss of function” (lof) mutants from components of the high osmolarity glycerol (HOG) signaling pathway in the filamentous fungus Magnaporthe oryzae are viable, but impaired in osmoregulation. Results After long-term cultivation upon high osmolarity, stable individuals with reestablished osmoregulation capacity arise independently from each of the mutants with inactivated HOG pathway. This phenomenon is extremely reproducible and occurs only in osmosensitive mutants related to the HOG pathway – not in other osmosensitive Magnaporthe mutants. The major compatible so…
Specific stress-induced storage of trehalose, glycerol and D-arabitol in response to oxidative and osmotic stress in Candida albicans.
2012
Candida albicans exponential yeast cells are able to face environmental challenges by mounting a rapid and efficient "general stress response". Here we show that one of the main components of this response consists of the intracellular protective accumulation of the non-reducing disaccharide trehalose and two polyols, glycerol and D-arabitol, an accumulation that occurs in a stress-specific dependent manner. Thus, oxidative exposures promoted a marked increase in both trehalose and D-arabitol in the wild type strain, RM-100, whereas the glycerol content remained virtually unaffected with respect to basal levels. In contrast, osmotic challenges induced the significant storage of glycerol acc…
The yeast osmosensitive mutant fps1Δ transformed by the cauliflower BobTIP1;1 aquaporin withstand a hypo-osmotic shock
2005
AbstractOsmoregulation plays an important role in cellular responses to osmotic stress in plants and in yeast. Aquaporins contribute to osmotic adjustment by facilitating transport of water or solutes across membranes. The tonoplastic water channel BobTIP1;1 (original name BobTIP26-1) genes are upregulated during dessication stress in cauliflower meristematic tissue. To investigate the physiological importance of BobTIP1;1, we expressed it in a Saccharomyces cerevisiae osmosensitive mutant fps1Δ. We showed that the defect in the yeast glycerol plasma membrane transporter is complemented by a plant cDNA encoding the aquaporin BobTIP1;1 which is localized in the vacuolar membrane of the compl…
The influence of the mean stress on fatigue life of 10HNAP steel under random loading
2001
Abstract This paper contains the results of uniaxial random load fatigue tests with different mean values performed on 10HNAP steel specimens. The experimental fatigue life was compared with the life determined according to different methods of amplitude transformation of the cycles. Cycles were counted with the rain flow algorithm and damage was cumulated with the Palmgren–Miner hypothesis. It has been shown that in the case of “symmetric” stress histories with zero expected values, the mean values of selected cycles do not strongly influence the calculated fatigue life and transformation of the cycle amplitudes; hence, no mean stress correction for cycle mean values different from zero is…
Oxidative stress tolerance, adenylate cyclase, and autophagy are key players in the chronological life span of Saccharomyces cerevisiae during winema…
2012
Most grape juice fermentation takes place when yeast cells are in a nondividing state called the stationary phase. Under such circumstances, we aimed to identify the genetic determinants controlling longevity, known as the chronological life span. We identified commercial strains with both short (EC1118) and long (CSM) life spans in laboratory growth medium and compared them under diverse conditions. Strain CSM shows better tolerance to stresses, including oxidative stress, in the stationary phase. This is reflected during winemaking, when this strain has an increased maximum life span. Compared to EC1118, CSM overexpresses a mitochondrial rhodanese gene-like gene, RDL2, whose deletion lead…
DNA damage by bromate: Mechanism and consequences
2005
Abstract Exposure of mammalian cells to bromate (BrO3−) generates oxidative DNA modifications, in particular 7,8-dihydro-8-oxo-guanine (8-oxoG). The damaging mechanism is quite unique, since glutathione, which is protective against most oxidants and alkylating agents, mediates a metabolic activation, while bromate itself does not react directly with DNA. Neither enzymes nor transition metals are required as catalysts in the activation. The ultimate DNA damaging species has not yet been established, but experiments under cell-free conditions suggest that neither molecular bromine nor reactive oxygen species such as superoxide, hydrogen peroxide or singlet oxygen are involved. Rather bromine …
Fanconi's anaemia cells have normal steady-state levels and repair of oxidative DNA base modifications sensitive to Fpg protein
1998
Abstract Cells from Fanconi's anaemia (FA) patients are abnormally sensitive to oxygen. However, a distinct genetic defect in either the cellular defence against reactive oxygen species (ROS) or in their metabolic generation has not been identified to date. Recently, the gene for the human 8-hydroxyguanine (8-oxoG) glycosylase, which removes this oxidative base modification from the genome, has been localized on chromosome 3p25, i.e., in the same region as the FA complementation group D (FAD) gene. We therefore studied the removal of photosensitization-induced 8-oxoG residues from the DNA of FA cells, using Fpg protein, the bacterial 8-oxoG glycosylase, to quantify the lesions by alkaline e…
tert-Butoxyl radicals generate mainly 7,8-dihydro-8-oxoguanine in DNA.
2000
Abstract Like hydroxyl radicals, alkoxyl radicals have been implicated in the generation of cellular oxidative DNA damage under physiological conditions; however, their genotoxic potential has not yet been established. We have analyzed the DNA damage induced by a photochemical source of tert- butoxyl radicals, the water soluble peroxy ester [4-( tert -butyldioxycarbonyl)benzyl]triethylammonium chloride (BCBT), using various repair endonucleases as probes. The irradiation (UV 360 ) of BCBT in the presence of bacteriophage PM2 DNA was found to generate a DNA damage profile that consisted mostly of base modifications sensitive to the repair endonuclease Fpg protein. Approximately 90% of the mo…
Extracellular cyclic GMP and its derivatives GMP and guanosine protect from oxidative glutamate toxicity.
2013
Cell death in response to oxidative stress plays a role in a variety of neurodegenerative diseases and can be studied in detail in the neuronal cell line HT22, where extracellular glutamate causes glutathione depletion by inhibition of the glutamate/cystine antiporter system xc(-), elevation of reactive oxygen species and eventually programmed cell death caused by cytotoxic calcium influx. Using this paradigm, we screened 54 putative extracellular peptide or small molecule ligands for effects on cell death and identified extracellular cyclic guanosine monophosphate (cGMP) as a protective substance. Extracellular cGMP was protective, whereas the cell-permeable cGMP analog 8-pCPT-cGMP or the …
Prädiktoren von lebenslanger Delinquenz
2006
Zusammenfassung. Theoretischer Hintergrund: Die Unterscheidung zwischen jugendgebundener und persistierender Delinquenz ist von theoretischer und praktischer Relevanz. Fragestellung: Relevante Merkmale für persistierende Delinquenz sollen identifiziert werden. Methode: Frühe Delinquenz, belastende Lebensereignisse, Copingstile und Persönlichkeitsvariablen wurden an 241 männlichen Straftätern untersucht. Ergebnisse: Straftäter mit langen Haftstrafen unterschieden sich von solchen mit kürzerer Haftdauer in der Persönlichkeitsstruktur sowie dem Bewältigungsverhalten. Früheres aggressives, antisoziales Verhalten leistete keinen substanziellen Anteil zur Gruppentrennung, während das Ausmaß schw…