This study tests the hypothesis that lowering intracellular pH (pHi) in melanoma cells grown at low extracellular pH (pHe) selectively abrogates 42 degrees C-induced heat shock protein (HSP) expression and reduces survival. Cells were acidified by a combination of a 0.2-pH-unit decrease in pHe coupled with the lactate/H+ transport inhibitor ...

Eukaryotic cells have a highly conserved response to an increase in temperature, termed the heat shock response. Recent research has revealed multiple roles for various sphingolipids in the heat shock responses of both yeast and mammalian cells. Heat stressed or shocked yeast and mammalian cells have an acute activation of ...

Stress-induced effects in human acute leukaemia cells (HL-60) were studied by flow cytometry using the fluorescent dye carboxyfluorescein succinimidyl ester which allows the analysis of several successive cell generations for up to 10 days. Asynchronously cycling cells subjected to heat shock (30 min at 41 degrees C) responded in two ...

Recently the low host specificity of some microsporidians has been demonstrated and it has been indicated that many of these micro-organisms could be transmitted from invertebrates to mammals and adapt to changes in temperature. In this work, we demonstrate the first successful in vitro culture of a fish microsporidia of ...

The threat of pathogen survival following ozone treatment of meat necessitates careful evaluation of the microorganisms surviving under such circumstances. The objective of this study was to determine whether sublethal aqueous ozone treatment (3 ppm of O3 for 5 min) of microorganisms on beef surfaces would result in increased or ...

The chronological changes in intracellular Ca(2+)concentrations ([Ca(2+)](i)) were analysed during heat-induced apoptosis in human lung cancer cell lines LK-2 (squamous cell carcinoma) and LU65A (large cell carcinoma). In LK-2 cells, increased [Ca(2+)](i) levels were maintained at levels between 250-350 nm 9 h after heat-shock. Treatment with BAPTA, an intracellular Ca(2+) ...

The neurodegenerative properties of the organophosphate ester leptophos (LEP) and the carbamate ester carbaryl (CB), both of which can cause neuropathic effects in animals, were investigated in differentiating mouse N2a neuroblastoma cells. At a sublethal concentration of 3 microM, both LEP and CB were able to inhibit the outgrowth of ...

The detrimental effects of heat stress on fertility in cattle are less pronounced in heat-tolerant breeds. Although these genetic differences reflect differences in thermoregulation, cells from heat-tolerant breeds are less adversely compromised by increased temperature (that is, heat shock) than cells from heat-sensitive breeds. Experiments were performed to test the ...

The heat resistance of exponential phase cells of environmental barley isolates <I>Enterococcus faecium</I> BAR<SUB> 1</SUB> and a hospital isolate <I>Enterococcus faecalis</I> MI <SUB>2</SUB> grown at 37 or 45<SUP> </SUP>was determined at 55, 60 and 62.5 ° C for 30 min. From the survival curves, the decimal reduction times (D-values) were ...

Accumulation of HSP70 is related to the cytoprotection. It was evaluated whether hyperosmotic stress induces HSP70 accumulation in LLC-PK1 cells, and protects cells against toxicity provoked by cisplatin (Cis) and cyclosporine A (CyA). Cells were maintained in isosmotic (Iso) or hyperosmotic (H) culture medium for 24 h and then exposed ...

A biowaste kill system was implemented to treat biological waste generated from a clinical manufacturing and R&D antibody facility. To confirm that design parameters of this continuous decontamination system are sufficient to inactivate mammalian cell culture waste, bench-scale experiments were conducted. The biowaste kill system heat inactivates mammalian cell cultures ...

Thermotherapy has been applied to various joint diseases and injuries, but its direct effects on articular cartilage have remained unclear. The present study examined the effects on cell viability and metabolism by using the chondrocyte-like cell line HCS-2/8. The temperatures and durations of heat stimulation were 39 degrees, 41 degrees, ...

We investigated the characteristics of morphology, DNA synthesis and argyrophilic nucleolar organizer regions (AgNORs) on murine Dunn osteosarcoma cells in response to heat (42 degrees C, 1 h) or dibutyryl cyclic adenosine 3',5'-monophosphate (Bt(2)cAMP). The cell morphology changes to a fibroblast-like appearance with long and thin protoplastic processes with the ...

The enterocytes of the small intestine are occasionally exposed to pathogenic bacteria, such as Salmonella enteritidis 857, an etiologic agent of intestinal infections in humans. The expression of the heat shock response by enterocytes may be part of a protective mechanism developed against pathogenic bacteria in the intestinal lumen. We ...

We determined whether the cytoprotective heat shock protein HSP72 protects against the injurious effects of Clostridium difficile toxin A (TxA) on intestinal epithelial cells. Colonic epithelial Caco-2/bbe (C2) cells were stably transfected with HSP72 antisense (C2AS) or vector only (C2VC), resulting in low and high HSP72 expression, respectively. Measurements of ...

We have used human cell lines, namely, K562 and HeLa cells as model systems in understanding the mechanism of lead toxicity and heat shock, that may be mediated by the heme-regulated eIF-2alpha kinase which is also called the heme-regulated inhibitor (HRI). RT-PCR analysis using HRI-specific primers indicated a two- to ...

The effect of sodium azide in heat shock-induced cell death was studied in Debaryomyces vanrijiae, Candida albicans, and Saccharomyces cerevisiae yeasts. The results presented demonstrate that the azide addition induced a drastic decrease in the thermotolerance of glucose-grown D. vanrijiae. In contrast, glucose-grown S. cerevisiae and C. albicans cells treated ...

High concentrations of oxygen (hyperoxia) are known to cause cellular injury and death. The heat shock response is a highly conserved cellular defense mechanism that protects cells against various environmental stressors, including hyperoxia. Herein we determined the role of heat shock factor-1 (HSF-1), a major component of the heat shock ...

The 90-kDa heat shock proteins (HSP90) are important in the regulation of numerous intracellular processes in eukaryotic cells. In particular, HSP90 has been shown to be involved in the control of the cellular differentiation of the protozoan parasite Leishmania donovani. We investigated the role of HSP90 in the related parasite ...

Plasmodesmata establish a pathway for the trafficking of non-cell-autonomously acting proteins and ribonucleoprotein complexes. Plasmodesmal enriched cell fractions and the contents of enucleate sieve elements, in the form of phloem sap, were used to isolate and characterize heat shock cognate 70 (Hsc70) chaperones associated with this cell-to-cell transport pathway. Three ...

Sphingolipids are abundant components of eucaryotic membranes, where they perform essential functions. To uncover new roles for sphingolipids, we studied Saccharomyces cerevisiae lcb1-100 cells, which have a temperature-sensitive block in the first step in sphingolipid synthesis. We find that the level of all five species of the sphingoid long chain ...

The intermediate filament cytoskeleton is thought to confer physical resilience on tissue cells, on the basis of extrapolations from the phenotype of cell fragility that results from mutations in skin keratins. There is a need for functional cell assays in which the impact of stress on intermediate filaments can be ...

The latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) causes cellular transformation and activation of several intracellular signaling events. In this report, we show that BLMP1 (encoded by the LMP1 gene derived from the B95-8 strain of EBV) triggers the expression of inducible nitric oxide synthase (iNOS) in Balb/3T3 ...

Physiological studies of neurons in raphe magnus (RM) and the adjacent nucleus reticularis magnocellularis (NRMC) have demonstrated that the response to noxious cutaneous stimulation predicts the response to opioid administration and therefore a cell's functional role in nociceptive modulation. Although visceral stimulation, like opioids, elicits antinociception, little is known about ...

Bone is subjected to a variety of physiological, as well as cell-deforming biomechanical stresses, including hydrostatic compression and fluid flow. However, little is known about the molecular mechanisms that protect bone cells from mechanical, ischemic, or oxidative damage. Crystallins are 20 kD heat shock proteins that function as molecular chaperones. ...

In order to determine whether there is a difference in effect on cell morphology and function between two common arthroscopic irrigation solutions, primary cultures of cells derived from the surgically excised human menisci were incubated for 3 or 6 h in lactated Ringer's solution, isotonic sodium chloride solution, or serum-free ...

Renal medullary cells are exposed to elevated and variable osmolarities and low oxygen tension. Despite the harsh environment, these cells are resistant to the effects of many harmful events. To test the hypothesis that this resistance is a consequence of these cells developing a stress tolerance phenotype to survive in ...

We have investigated the role of stress-activated signaling pathways and the small heat shock protein, Hsp27, in protecting PC12 cells from heat shock and nerve growth factor (NGF) withdrawal-induced apoptosis. PC12 cells and a stable cell line overexpressing Hsp27 (HSPC cells) were subjected to heat shock. This resulted in the ...

Treatment (>/=6 h) of cultured bovine adrenal chromaffin cells with geldanamycin (GA) or herbimycin A (HA), an inhibitor of the 90-kDa heat-shock protein (Hsp90) family, decreased cell surface (125)I-insulin binding. The effect of GA was concentration (EC(50) = 84 nM)- and time (t(1/2) = 8.5 h)-dependent; GA (1 microM for ...

Inducible nitric oxide synthase (iNOS) is responsible for nitric oxide (NO) synthesis from l-arginine in response to inflammatory mediators. We have previously shown that iNOS is degraded through the 26S proteasome. Targeting of proteins for proteasomal degradation may or may not require their covalent linkage to multiubiquitin chains (ubiquitination). In ...

The present study was undertaken to determine if short duration (1-2 h), moderate hyperthermia (41.1 degrees C) could radiosensitize human tumour cells. It was found that moderate hyperthermia (41.1 degrees C), for as little as 1 h, can radiosensitize heat resistant human adenocarcinoma cells, NSY42129 (NSY), provided the cells are ...

The nuclear phenotypes of Malpighian tubule cells in fifth instar nymphs of Triatoma infestans, one of the most important vectors of Chagas disease, were studied following sequential shocks at 0 degrees C, separated by intervals of 8 h and 24 h at 30 degrees C, under conditions of moderate fasting ...

OBJECTIVE: To examine the relationships between the form of cell death (apoptosis or necrosis), reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and the level of heat-shock protein 70 (hsp 70) expression after thermotherapy of PC-3 prostate cancer cells; also assessed were the tumoricidal effects of combined treatment with ...

Rat H9c2 myoblasts were preconditioned by heat or metabolic stress followed by recovery under normal conditions. Cells were then subjected to severe ATP depletion, and stress-associated proteotoxicity was assessed on 1) the increase in a Triton X-100-insoluble component of total cellular protein and 2) the rate of inactivation and insolubilization ...

In eukaryotic cells, environmental stress signals are transmitted by evolutionarily conserved MAPKs, such as Hog1 in the budding yeast Saccharomyces cerevisiae, Spc1 in the fission yeast Schizosaccharomyces pombe and p38/JNK in mammalian cells. Here, we report the identification of the Aspergillus nidulans sakA gene, which encodes a member of the ...

We identified the recA gene of the moderately thermophilic bacterium Streptococcus thermophilus and investigated the role of its product in the adaptation to heat shock and nutrient starvation. Expression of recA was required for optimal viability and normal cell morphology upon induction of both stresses. Normal induction of GroEL and ...

Huntington's disease is one of nine known neurodegenerative disorders caused by an expanded polyglutamine (poly(Q)) tract in the disease protein. These diseases are associated with intraneuronal protein aggregates. Heat-inducible chaperones like HSP70 and HSP27 suppress poly(Q) aggregation and/or toxicity/cell death. Heat shock transcription factors, including HSF-1, regulate HSP70 and HSP27 ...

A chimeric protein consisting of enhanced green fluorescent protein (EGFP) fused to the N-terminus of human Hsp27 conferred stress protection in human A549 lung carcinoma and murine L929 cells that were stably transfected to express the chimera constitutively. The resultant protection was comparable with that in the same cell lines ...

Normal human diploid cells and various human tumour cells were heat shocked at 43 degrees C for 2h and allowed to recover at 37 degrees C. It was found that heat shock treatment transiently disrupted the immunostaining of centrosomes, and no centrosome staining was detected in either normal or tumour ...

A rapid, reliable microwell plate method based on the most probable number (MPN) technique was used to determine the effectiveness of five enrichment regimes in the recovery and enumeration of Listeria spp. cells from five seafood products. The products tested were chosen to reflect conditions under which cells were exposed ...

Heat-induced cell death and apoptosis were studied with respect to intracellular ATP. Studies on the relationship between hyperthermic cell-killing at 44 degrees C and cellular ATP levels in four cell lines grown as monolayers and six cell lines grown in suspension showed good correlations between cellular ATP levels and the ...

The stress metabolic activities of Panax ginseng (P. ginseng) cells induced by low-energy ultrasound (US) were examined. P. ginseng cells in suspension cultures were exposed to 38.5 kHz US at two power levels (power density 13.7 and 61 mW/cm(3)) for 2 min. The US treatment caused rapid increase in the ...

The thermal responses of mouse colorectal carcinoma cells were investigated in the wild type cells and the transfected cells with human FUT1 gene which encodes alpha 1,2fucosyltransferase. The heat sensitivity was observed to increase in the FUT1 gene transfected cells and the effect of hyperthermia at 44 degrees C on ...

PURPOSE: It is well established that salicylate and several other non-steroidal anti-inflammatory agents (NSAID), including indomethacin, can activate the heat-shock response, albeit at high concentrations. This is significant since heat shock significantly alters the cellular cytotoxic response to ionizing radiation (IR). It was previously shown that heat shock, as well ...

We previously reported that steryl glucoside (SG) is rapidly induced in cells from molds to humans by exposure to environmental stress (Murakami-Murofushi et al. (1997) J. Biol. Chem., 272, 486-489, Kunimoto et al. (2000) Cell Stress & Chaperones, 5, 3-7), and in mold cells SG production is followed by activation ...

The 90-kDa heat shock protein, HSP90, is an abundant molecular chaperone which functions in cellular homeostasis in prokaryotes and eukaryotes. It is well known that HSP90 plays a critical and indispensable role in regulating cell growth through modulations of various signal transduction pathways, but its roles in cell cycle control ...

PURPOSE: To determine potential hazards from exposure to a high-frequency electromagnetic field (HFEMF) at 2.45 GHz by studies of the expression of heat-shock protein 70 (hsp70) in MO54 cells. METHOD: MO54 cells were exposed to a HFEMF at average specific absorption rates (SAR) of 5, 20, 50 and 100 W/kg, ...

The antimicrotubule drug estramustine phosphate (EMP) has been shown to sensitize prostate carcinoma cells to radiation via synchronization at the G2/M phase of the cell cycle. This synchronization may also render cells more sensitive to hyperthermia, providing a rationale for multimodal treatment approaches. We have investigated the effects of EMP ...

CHO cells are normally sensitized to hyperthermia by acidic pH. However, CHO cells adapted to growth in pH 6.7 medium become less sensitive to heat killing at the reduced pH. The adapted cells maintain their ability to develop thermotolerance at pH 6.7 and their steady state intracellular pH is elevated. ...

A new type of cell-cultivation system based on photo-thermal etching has been developed for the on-chip cultivation of living cells using an agarose microchamber array. The method can be used to flexibly change the chamber structure by photo-thermal etching, even during the cultivation of cells, depending upon the progress in ...