Elevation of the heat resistance of Salmonella typhimurium by sublethal heat shock

The survival of Salmonella typhimurium after a standard heat challenge at 55°C for 25 min increased by several orders of magnitude when cells grown at 37°C were pre-incubated at 42°, 45° or 48°C before heating at the higher temperature. Heat resistance increased rapidly after the temperature shift, reaching near maximum levels within 30 min. Elevated heat resistance persisted for at least 10 h. Preincubation of cells at 48°C for 30 min increased their resistance to subsequent heating at 50°, 52°, 55°, 57° or 59°C. Survival curves of resistant cells were curvilinear. Estimated times for a '7D' inactivation increased by 2.6- to 20-fold compared with cells not pre-incubated before heat challenge.     

Elevation of the heat resistance of Salmonella typhimurium by sublethal heat shock

The survival of Salmonella typhimurium after a standard heat challenge at 55 degrees C for 25 min increased by several orders of magnitude when cells grown at 37 degrees C were pre-incubated at 42 degrees, 45 degrees or 48 degrees C before heating at the higher temperature. Heat resistance increased rapidly after the temperature shift, reaching near maximum levels within 30 min. Elevated heat resistance persisted for at least 10 h. Pre-incubation of cells at 48 degrees C for 30 min increased their resistance to subsequent heating at 50 degrees, 52 degrees, 55 degrees, 57 degrees or 59 degrees C. Survival curves of resistant cells were curvilinear. Estimated times for a '7D' inactivation increased by 2.6- to 20-fold compared with cells not pre-incubated before heat challenge.     

Interaction of the Neurospora crassa heat shock factor with the heat shock element during heat shock and different developmental stages

The interaction of the heat shock factor (HSF) with the heat shock element (HSE) was determined by a non-radioactive electrophoretic mobility shift assay, in order to analyze HSF regulation in Neurospora crassa. HSF binds to HSE under normal, non-stress conditions and is thus constitutively trimerized. Upon heat shock, the HSF-HSE complex shows a retarded mobility. This was also observed in Saccharomyces cerevisiae, where this mobility shift was shown to be due to HSF phosphorylation [Sorger and Pelham (1988) Cell 54, 855-864]. In N. crassa, HSE-dependent electrophoretic mobility shift is temperature- and time-dependent. Under normal growth conditions, the HSF is located in the cytoplasm as well as in the nucleus. In germinating conidia the HSF shows a retarded mobility typical for heat shock even at normal growth temperatures. No HSF-dependent mobility shift was detectable in aerial hyphae.     

温度和渗透应激对植物乳杆菌稳定性的影响

在植物乳杆菌对数期后期,高温（43—47℃）、低温（15—25℃）及10-30g/L NaCl等应激处理60min均可使植物乳杆菌耐热性和耐酸性得到较大的提高。其中,尤以高温应激45℃应激处理效果最好,细胞耐热残存率和耐酸残存率较对照分别提高124％和56．8％。     

Discovery of the heat shock response

No Abstract Available     

Characterization of the heat shock response in cultured sugarcane cells : I. Physiology of the heat shock response and heat shock protein synthesis

Effect of heat shock on the growth of cultured sugarcane cells (Saccharum officinarum L.) was measured. Heat shock (HS) treatment at 36 to 38°C (2 hours) induced the development of maximum thermotolerance to otherwise nonpermissive heat stress at 54°C (7 minutes). Optimum thermotolerance was observed 8 hours after heat shock. Development of thermotolerance was initiated by treatments as short as 30 minutes at 36°C. Temperatures below 36°C or above 40°C failed to induce maximum thermotolerance. In vivo labeling revealed that HS at 32 to 34°C induced several high molecular mass heat shock proteins (HSPs). A complex of 18 kilodalton HSPs required at least 36°C treatment for induction. The majority of the HSPs began to accumulate within 10 minutes, whereas the synthesis of low molecular mass peptides in the 18 kilodalton range became evident 30 minutes after initiation of HS. HS above 38°C resulted in progressively decreased HSP synthesis with inhibition first observed for HSPs larger than 50 kilodaltons. Analysis of two-dimensional gels revealed a complex pattern of label incorporation including the synthesis of four major HSPs in the 18 kilodalton range and continued synthesis of constitutive proteins during HS.     

NCLX pumps up the heat

Mitochondrial Ca²⁺ signaling is a well-appreciated regulator of cell metabolism and energy production. A major function of mitochondria in brown adipose tissue (BAT) is thermogenesis. Assali et al. offer new insights into how the mitochondrial Ca²⁺ extrusion mediator NCLX is crucial for BAT survival and thermogenesis.