scholarly journals Heat Shock Proteins Do Not Influence Wet Heat Resistance of Bacillus subtilis Spores

2001 ◽  
Vol 183 (2) ◽  
pp. 779-784 ◽  
Author(s):  
Elizabeth Melly ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Resistance ◽  
Significant Role ◽  
Vegetative Cell ◽  
Heat Shock Genes ◽  
Wet Heat ◽  
Shock Proteins

ABSTRACT Spores of Bacillus subtilis are significantly more resistant to wet heat than are their vegetative cell counterparts. Analysis of the effects of mutations in and the expression of fusions of a coding gene for a thermostable β-galactosidase to a number of heat shock genes has shown that heat shock proteins play no significant role in the wet heat resistance of B. subtilis spores.

scholarly journals Functional Analysis of Genes Comprising the Locus of Heat Resistance in Escherichia coli

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
Ryan Mercer ◽  
Oanh Nguyen ◽  
Qixing Ou ◽  
Lynn McMullen ◽  
Michael G. Gänzle
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Resistance ◽  
Growth Phase ◽  
Genomic Island ◽  
Enteric Bacteria ◽  
Content Type ◽  
E Coli ◽  
Shock Proteins

ABSTRACT The locus of heat resistance (LHR) is a 15- to 19-kb genomic island conferring exceptional heat resistance to organisms in the family Enterobacteriaceae, including pathogenic strains of Salmonella enterica and Escherichia coli. The complement of LHR-comprising genes that is necessary for heat resistance and the stress-induced or growth-phase-induced expression of LHR-comprising genes are unknown. This study determined the contribution of the seven LHR-comprising genes yfdX1 GI, yfdX2, hdeD GI, orf11, trx GI, kefB, and psiE GI by comparing the heat resistances of E. coli strains harboring plasmid-encoded derivatives of the different LHRs in these genes. (Genes carry a subscript “GI” [genomic island] if an ortholog of the same gene is present in genomes of E. coli.) LHR-encoded heat shock proteins sHSP20, ClpKGI, and sHSPGI are not sufficient for the heat resistance phenotype; YfdX1, YfdX2, and HdeD are necessary to complement the LHR heat shock proteins and to impart a high level of resistance. Deletion of trx GI, kefB, and psiE GI from plasmid-encoded copies of the LHR did not significantly affect heat resistance. The effect of the growth phase and the NaCl concentration on expression from the putative LHR promoter p2 was determined by quantitative reverse transcription-PCR and by a plasmid-encoded p2:GFP promoter fusion. The expression levels of exponential- and stationary-phase E. coli cells were not significantly different, but the addition of 1% NaCl significantly increased LHR expression. Remarkably, LHR expression in E. coli was dependent on a chromosomal copy of evgA. In conclusion, this study improved our understanding of the genes required for exceptional heat resistance in E. coli and factors that increase their expression in food. IMPORTANCE The locus of heat resistance (LHR) is a genomic island conferring exceptional heat resistance to several foodborne pathogens. The exceptional level of heat resistance provided by the LHR questions the control of pathogens by current food processing and preparation techniques. The function of LHR-comprising genes and their regulation, however, remain largely unknown. This study defines a core complement of LHR-encoded proteins that are necessary for heat resistance and demonstrates that regulation of the LHR in E. coli requires a chromosomal copy of the gene encoding EvgA. This study provides insight into the function of a transmissible genomic island that allows otherwise heat-sensitive enteric bacteria, including pathogens, to lead a thermoduric lifestyle and thus contributes to the detection and control of heat-resistant enteric bacteria in food.

The expression of heat-shock genes in higher plants

1986 ◽  
Vol 314 (1166) ◽  
pp. 453-468 ◽  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Higher Plants ◽  
Structural Features ◽  
Amino Acid Sequences ◽  
Heat Shock Gene ◽  
Regulatory Sequences ◽  
Heat Shock Genes ◽  
Control Of Gene Expression ◽  
Shock Proteins

High-temperature stress or heat shock induces the vigorous synthesis of heat-shock proteins in many organisms including the higher plants. This response has been implicated in the acquisition of thermotolerance. The biological importance of a group of low-molecular-mass proteins in the response of plants is indicated by the conservation of the corresponding genes. The steady-state levels of mRNAs for these proteins shift from undetectable levels at normal temperature to about 20 000 molecules per gene in the cell after heat shock. The analysis of ‘run-off’ transcripts from isolated soybean nuclei suggests a transcriptional control of gene expression. The DNA sequence analysis of soybean heat-shock genes revealed a conservation of promoter sequences and 5'-upstream elements. A comparison of the deduced amino acid sequences of polypeptides showed a conservation of structural features in heat-shock proteins between plants and animals. The implication of a common regulatory concept in the heat-shock response makes genes belonging to this family (15-18 kDa proteins) in soybean favourable candidates for investigating thermoregulation of transcription. We have exploited the natural gene transfer system of Agrobacterium tumefaciens to introduce a soybean heat-shock gene into the genomes of sunflower and tobacco. The gene is thermoinducibly transcribed and transcripts are faithfully initiated in transgenic plants. Experiments are in progress to define the regulatory sequences 5'-upstream from the gene. The expression of heat-shock genes in a heterologous genetic background also provides the basis for studying the function of the proteins and their possible role in thermoprotection.

The Escherichia coli chaperones involved in DNA replicadon

1993 ◽  
Vol 339 (1289) ◽  
pp. 271-278 ◽  
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Conformational Changes ◽  
Heat Shock Genes ◽  
Dnab Helicase ◽  
Initiation Of Dna Replication ◽  
Shock Proteins

Mutadons in the Escherichia coli heat shock genes, dnaK , dnaJ or grpE , alter host DNA and RNA synthesis, degradation of other proteins, cell division and expression of other heat shock genes. They also block the initiation of DNA replication of bacteriophages λ and P1, and the mini-F plasmid. An in vitro λDNA replication system, composed entirely of purified components, enabled us to describe the molecular mechanism of the dnaK , dnaJ and grpE gene products. DnaK , the bacterial hsp 70 homologue, releases λP protein from the preprimosomal complex in an ATP- and DnaJ-dependent reaction (GrpEindependent initiation of λDNA replication). In this paper, I show that, when GrpE is present, λP protein is not released from the preprimosomal complex, rather it is translocated within the complex in such a way that it does not inhibit DnaB helicase activity. Translocation of λP triggers the initiation event allowing DnaB helicase to unwind DNA near the ori λ sequence, leading to efficient λDNA replication. Chaperone activity of the DnaK -DnaJ-GrpE system is first manifested in the selective binding of these heat shock proteins to the preprimosomal complex, followed by its ATP-dependent rearrangement. I show that DnaJ not only tags the preprimosomal complex for recognition by DnaK, but also stabilizes the multi-protein structure. GrpE also participates in the binding of DnaK to the preprimosomal complex by increasing DnaK ’s affinity to those λP proteins which are already associated with DnaJ. After attracting DnaK to the preprimosomal complex, DnaJ and GrpE stimulate the ATPase activity of DnaK , triggering conformational changes in DnaK which are responsible for the rearrangement of proteins in the preprimosomal complex and recycling of these heat shock proteins. The role of DnaK , DnaJ and GrpE in λDNA replication is in sharp contrast to our understanding of their role in the oriC , P1, and probably mini-F DNA replication systems. In the cases of oriC and P1 DNA replication, these heat shock proteins activate initiation factors before they are in contact with DNA, and are not required during the subsequent steps leading to the initiation of DNA replication. The common feature of DnaK , DnaJ and GrpE action in these systems is their ATP-dependent disaggregation or rearrangement of protein complexes formed before or during initiation of DNA replication.

scholarly journals Short Review on Types of Heat Shock Proteins and Their Fundamental Characters for Body Maintenance Together With Role in Cancer

2020 ◽  
pp. 103-108
Author(s):  
Muhammad Muneeb ◽  
Moazam Ali ◽  
Tahir Sarfaraz ◽  
Wajid Ali ◽  
Zeeshan Ahmad Bhutta
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Protein ◽  
Significant Role ◽  
Cancer Diagnosis ◽  
Short Review ◽  
The Body ◽  
Normal Functions ◽  
Wide Range ◽  
Shock Proteins

Body of living thing is a complex machine that works on multifunctional processes and needs maintenance. Heat shock protein is a specific type of protein that cares about many normal functions of the body. These proteins have many dynamic occupations to shield the body from various diseases and also a key role in the coiling and uncoiling of proteins, prevent from apoptosis and transportation of proteins. Along with these all properties, the foremost function of these proteins is prevention from cancer and a significant role in cancer diagnosis. Commonly heat shock protein known as chaperones and a wide range of their types have been discovered with their functions as well. Recently many scientists are working on additional investigation of heat shock proteins. This review concludes some basic types of heat shock proteins and their elegant purposes and also providing an open eye for new scientist about a further investigation of heat shock protein.

scholarly journals High constitutive levels of heat-shock proteins in human-pathogenic parasites of the genus Leishmania

1995 ◽  
Vol 310 (1) ◽  
pp. 225-232 ◽  
Author(s):  
S Brandau ◽  
A Dresel ◽  
J Clos
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
State Level ◽  
Protozoan Parasite ◽  
Cellular Stress Response ◽  
Transcriptional Level ◽  
Heat Shock Genes ◽  
Leishmania Promastigotes ◽  
Shock Proteins

We have analysed the transcription of three heat-shock genes, HSP70, HSP83 and ClpB, in the protozoan parasite Leishmania. All three heat-shock genes are transcribed constitutively and not heat-inducibly. However, we find that two major heat-shock proteins, HSP70 and HSP83, are synthesized at elevated rates during heat stress. We conclude that the cellular stress response in Leishmaniae is regulated exclusively on a post-transcriptional level much in contrast with all other eukaryotes examined so far. The induced synthesis of HSP70 and HSP83, however, does not increase the steady-state level of either protein significantly. This is compensated by high constitutive levels of both proteins: HSP70 and HSP83 make up 2.1% and 2.8%, respectively, of the total protein in unstressed Leishmania promastigotes. Also, HSP70 is a strictly cytoplasmic protein in Leishmania and does not relocate into the nucleus during heat stress, as it does in other eukaryotes examined in the past.

scholarly journals Activation of Heat Shock Genes Is Not Necessary for Protection by Heat Shock Transcription Factor 1 against Cell Death Due to a Single Exposure to High Temperatures

2003 ◽  
Vol 23 (16) ◽  
pp. 5882-5895 ◽  
Author(s):  
Sachiye Inouye ◽  
Kensaku Katsuki ◽  
Hanae Izu ◽  
Mitsuaki Fujimoto ◽  
Kazuma Sugahara ◽  
...  
Keyword(s):  
Cell Death ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Response ◽  
Single Exposure ◽  
Heat Shock Genes ◽  
Amino Terminal ◽  
Shock Response ◽  
Shock Proteins

ABSTRACT Heat shock response, which is characterized by the induction of a set of heat shock proteins, is essential for induced thermotolerance and is regulated by heat shock transcription factors (HSFs). Curiously, HSF1 is essential for heat shock response in mammals, whereas in avian HSF3, an avian-specific factor is required for the burst activation of heat shock genes. Amino acid sequences of chicken HSF1 are highly conserved with human HSF1, but those of HSF3 diverge significantly. Here, we demonstrated that chicken HSF1 lost the ability to activate heat shock genes through the amino-terminal domain containing an alanine-rich sequence and a DNA-binding domain. Surprisingly, chicken and human HSF1 but not HSF3 possess a novel function that protects against a single exposure to mild heat shock, which is not mediated through the activation of heat shock genes. Overexpression of HSF1 mutants that could not bind to DNA did not restore the susceptibility to cell death in HSF1-null cells, suggesting that the new protective role of HSF1 is mediated through regulation of unknown target genes other than heat shock genes. These results uncover a novel role of vertebrate HSF1, which has been masked underthe roles of heat shock proteins.

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