Heat Shock Response in the Thermophilic Enteric Yeast Arxiozyma telluris

1998 ◽  
Vol 64 (8) ◽  
pp. 3063-3065 ◽  
Author(s):  
Michelle L. Deegenaars ◽  
Kenneth Watson

ABSTRACT Heat stress tolerance was examined in the thermophilic enteric yeast Arxiozyma telluris. Heat shock acquisition of thermotolerance and synthesis of heat shock proteins hsp 104, hsp 90, hsp 70, and hsp 60 were induced by a mild heat shock at temperatures from 35 to 40°C for 30 min. The results demonstrate that a yeast which occupies a specialized ecological niche exhibits a typical heat shock response.

1994 ◽  
Vol 21 (6) ◽  
pp. 857 ◽  
Author(s):  
HT Nguyen ◽  
CP Joshi ◽  
N Klueva ◽  
J Weng ◽  
KL Hendershot ◽  
...  

The occurrence of heat-shock proteins (HSPs) in response to high temperature stress is a universal phenomenon in higher plants and has been well documented. However, in agriculturally important species, less is known about the expression of HSPs under natural environments. A review of the heat-shock response in wheat (Triticum aestivum L.) is presented and recent results on the expression of wheat HSPs under diurnal stress and field conditions are reported. In the field experiment, flag leaf blade temperatures were obtained and leaf blades collected for northern blot analysis using HSP 16.9 cDNA as a probe. Temperatures of leaf blades ranged from 32 to 35�C under the tested field conditions at New Deal near Lubbock, Texas. Messenger RNAs encoding a major class of low molecular weight HSPs, HSP 16.9, were detected in all wheat genotypes examined. The results suggested that HSPs are synthesised in response to heat stress under agricultural production, and furthermore, that HSPs are produced in wheats differing in geographic background. In the controlled growth chamber experiment, HSP expression in two wheat cultivars, Mustang (heat tolerant) and Sturdy (heat susceptible) were analysed to determine if wheat genotypes differing in heat tolerance differ in in vitro HSP synthesis (translatable HSP mRNAs) under a chronic, diurnal heat-stress regime. Leaf tissues were collected from seedlings over a time-course and poly (A)+RNAs were isolated for in vitro translation and 2-D gel electrophoresis. The protein profiles shown in the 2-D gel analysis revealed that there were not only quantitative differences of individual HSPs between these two wheat lines, but also some unique HSPs which were only found in the heat tolerant line. This data provides evidence of a correlation between HSP synthesis and heat tolerance in wheat under a simulated field environment and suggests that further genetic analysis of HSPs in a segregating population is worthy of investigation. In conclusion, the results of this study provide an impetus for the investigation of the roles of HSP genes in heat tolerance in wheat.


Genes ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 867
Author(s):  
Anthony D. Tercero ◽  
Sean P. Place

The suborder Notothenioidae is comprised of Antarctic fishes, several of which have lost their ability to rapidly upregulate heat shock proteins in response to thermal stress, instead adopting a pattern of expression resembling constitutive genes. Given the cold-denaturing effect that sub-zero waters have on proteins, evolution in the Southern Ocean has likely selected for increased expression of molecular chaperones. These selective pressures may have also enabled retention of gene duplicates, bolstering quantitative output of cytosolic heat shock proteins (HSPs). Given that newly duplicated genes are under more relaxed selection, it is plausible that gene duplication enabled altered regulation of such highly conserved genes. To test for evidence of gene duplication, copy number of various isoforms within major heat shock gene families were characterized via qPCR and compared between the Antarctic notothen, Trematomus bernacchii, which lost the inducible heat shock response, and the non-Antarctic notothen, Notothenia angustata, which maintains an inducible heat shock response. The results indicate duplication of isoforms within the hsp70 and hsp40 super families have occurred in the genome of T. bernacchii. The findings suggest gene duplications may have been critical in maintaining protein folding efficiency in the sub-zero waters and provided an evolutionary mechanism of alternative regulation of these conserved gene families.


1998 ◽  
Vol 23 (3) ◽  
pp. 245-260 ◽  
Author(s):  
J. Lon Kilgore ◽  
Timothy I. Musch ◽  
Christopher R. Ross

Selye (1936) described how organisms react to various external stimuli (i.e., stressors). These reactions generally follow a programmed series of events and help the organism adapt to the imposed stress. The heat shock response is a common cellular reaction to external stressors, including physical activity. A characteristic set of proteins is synthesised shortly after the organism is exposed to stress. Researchers have not determined how heat shock proteins affect the exercise response. However, their role in adaptation to exercise and training might he inferred, since the synthetic patterns correlate well with the stress adaptation syndrome that Selye described. This review addresses the 70 kilodalton heat shock protein family (HSP70), the most strongly induced heat shock proteins. This paper provides an overview of the general heat shock response and a brief review of literature on HSP70 function, structure, regulation, and potential applications. Potential applications in health, exercise, and medicine are provided. Key words: heat shock, protein, exercise


1991 ◽  
Vol 11 (2) ◽  
pp. 1062-1068
Author(s):  
H J Yost ◽  
S Lindquist

In the yeast Saccharomyces cerevisiae, the splicing of mRNA precursors is disrupted by a severe heat shock. Mild heat treatments prior to severe heat shock protect splicing from disruption, as was previously reported for Drosophila melanogaster. In contrast to D. melanogaster, protein synthesis during the pretreatment is not required to protect splicing in yeast cells. However, protein synthesis is required for the rapid recovery of splicing once it has been disrupted by a sudden severe heat shock. Mutations in two classes of yeast hsp genes affect the pattern of RNA splicing during the heat shock response. First, certain hsp70 mutants, which overproduce other heat shock proteins at normal temperatures, show constitutive protection of splicing at high temperatures and do not require pretreatment. Second, in hsp104 mutants, the recovery of RNA splicing after a severe heat shock is delayed compared with wild-type cells. These results indicate a greater degree of specialization in the protective functions of hsps than has previously been suspected. Some of the proteins (e.g., members of the hsp70 and hsp82 gene families) help to maintain normal cellular processes at higher temperatures. The particular function of hsp104, at least in splicing, is to facilitate recovery of the process once it has been disrupted.


2000 ◽  
Vol 278 (4) ◽  
pp. H1091-H1097 ◽  
Author(s):  
L. Sun ◽  
J. Chang ◽  
S. R. Kirchhoff ◽  
A. A. Knowlton

Heat-shock proteins (HSPs) are an important family of endogenous protective proteins, which increase in response to myocardial ischemia and other stresses. Overexpression of HSP72 is cardioprotective. We were interested in the regulation of heat-shock factor (HSF), the transcription factor for HSP genes. Previously we have observed that the inflammatory cytokine tumor necrosis factor-α increases HSP72 levels and postulated that dexamethasone might effect the heat shock response. In the adult rat cardiac myocyte we found that treatment with either low (10 μM)- or high (100 μM)-dose dexamethasone activated HSF by 2–6 h as determined by gel shift assay without evidence of cytotoxicity. Although HSF activation is a key step in expression of HSP72, this may not result in an increase in HSP72. We found that 10 μM dexamethasone increased HSP72 38%, and 100 μM dexamethasone increased HSP72 62% ( P < 0.05). HSP27 and HSP60 were unchanged. The selective increase in HSP72 was associated with protection of the cardiac myocytes from hypoxia and reoxygenation. We conclude that dexamethasone is a novel inducer of the heat shock response.


1988 ◽  
Vol 34 (10) ◽  
pp. 1148-1153 ◽  
Author(s):  
Michael W. Lema ◽  
Arnold Brown ◽  
Charles A. Butler ◽  
Paul S. Hoffman

The heat-shock response of Legionella pneumophila was examined by radiolabelling bacterial cell proteins with [35S]methionine following a temperature shift from 30 to 42 °C. Five heat-shock proteins were identified as having molecular masses of 17, 60, 70, 78, and 85 kilodaltons (kDa). The 85- and 60-kDa proteins were equally distributed between supernatant and pellet fractions following ultracentrifugation at 100 000 × g, the 70- and 78-kDa proteins were found primarily in the supernatant, and the 17-kDa protein was found primarily in the pellet. Synthesis of subsets of the heat-shock proteins could be stimulated by novobiocin, patulin, or puromycin. Ethanol, an effector of the heat-shock response in other microorganisms, had little effect on L. pneumophila, even at the highest concentration tolerated by the bacterial cells (1.9%). Finally, the 60-kDa heat-shock protein of L. pneumophila was immunologically cross-reactive with a polyclonal antibody prepared to the Escherichia coli groEL protein. However, a mouse monoclonal antibody reactive with the 60-kDa protein of all legionellae tested did not cross-react with the E. coli groEL protein, suggesting that the Legionella 60-kDa protein contains common and unique epitopes.


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