heat shock response

(noun)

The cellular response to heat shock.

Examples of heat shock response in the following topics:

  • The Heat-Shock Response

    • Heat shock response is a cell's response to intense heat, including up-regulation of heat shock proteins.
    • Heat shock response is the cellular response to heat shock includes the transcriptional up-regulation of genes encoding heat shock proteins (HSPs) as part of the cell's internal repair mechanism .
    • The up-regulation of HSPs during heat shock is generally controlled by a single transcription factor; in eukaryotes this regulation is performed by heat shock factor (HSF), while σ32 is the heat shock sigma factor in Escherichia coli.
    • Heat shock protein come in many sizes.
    • This is an example of small heat shock proteins produced by Pseudomonas aeruginosa Clonal Variants Isolated from Diverse Niches.

  • Repression of Anabolic Pathways

    • For example, when E. coli bacteria are subjected to heat stress, the σ32 subunit of its RNA polymerase changes in such a way that the enzyme binds to a specialized set of promoters that precede genes for heat-shock response proteins.

  • Activation of Starvation by Survival Genes

    • Stringent response is a stress response that occurs in bacteria and plant chloroplasts in reaction to stress conditions.
    • Stringent Response, also called stringent control, is a stress response that occurs in bacteria and plant chloroplasts in reaction to amino-acid starvation, fatty acid limitation, iron limitation, heat shock, and other stress conditions.
    • The stringent response is signaled by the alarmone (p)ppGpp and modulating transcription of up to 1/3 of all genes in the cell.
    • In other bacteria, stringent response is mediated by a variety of RelA/SpoT Homologue (RSH) proteins.
    • In bacteria stringent response is mediated by a variety of RelA/SpoT Homologue (RSH) proteins.

  • The Stringent Response

    • The stringent response is a stress response that occurs in bacteria in reaction to amino-acid starvation or other stress conditions.
    • The stringent response, also called stringent control, is a stress response that occurs in bacteria and plant chloroplasts in reaction to amino-acid starvation , fatty acid limitation, iron limitation, heat shock, and other stress conditions.
    • The stringent response is signaled by the alarmone (p)ppGpp and modulating transcription of up to 1/3 of all genes in the cell.
    • During the stringent response, (p)ppGpp accumulation affects the resource-consuming cell processes replication, transcription, and translation.
    • Explain the function of the alarmone (p)ppGpp in the stringent response

  • Sepsis and Septic Shock

    • Septic shock occurs when a body's response to an infection (sepsis) leads to life-threatening low blood pressure.
    • The mortality rate from septic shock is approximately 25–50%.
    • Sepsis is an illness in which the body has a severe response to bacteria or other germs.
    • A bacterial infection anywhere in the body may set off the response that leads to sepsis.
    • There are new drugs that act against the extreme inflammatory response seen in septic shock.

  • Bacterial Transformation

    • For transformation to happen, bacteria must be in a state of competence, which might occur as a time-limited response to environmental conditions such as starvation and cell density.
    • Typically, the cells are incubated in a solution containing divalent cations; most commonly, calcium chloride solution under cold condition, which is then exposed to a pulse of heat shock.
    • The heat-pulse is thought to create a thermal imbalance on either side of the cell membrane, which forces the DNA to enter the cells through either cell pores or the damaged cell wall.
    • Using this method, the cells are briefly shocked with an electric field of 10-20 kV/cm which is thought to create holes in the cell membrane through which the plasmid DNA may enter.
    • After the electric shock, the holes are rapidly closed by the cell's membrane-repair mechanisms.

  • Growth Rate and Temperature

    • For example, in molecular biology, the cold-shock domain (CSD) is a protein domain of about 70 amino acids which has been found in prokaryotic and eukaryotic DNA-binding proteins.
    • During the lag phase, the expression of around 13 proteins, which contain cold shock domains is increased two- to ten-fold.
    • These so-called cold shock proteins are thought to help the cell survive in temperatures lower than optimum growth temperature, by contrast with heat shock proteins, which help the cell survive in temperatures greater than the optimum, possibly by condensation of the chromosome and organization of the prokaryotic nucleoid.

  • Pyelonephritis

    • Severe cases of pyelonephritis can lead to pyonephrosis (pus accumulation around the kidney), sepsis (a systemic inflammatory response of the body to infection), kidney failure and even death.
    • Pyelonephritis that has progressed to urosepsis may be accompanied by signs of septic shock, including rapid breathing, decreased blood pressure, violent shivering, and occasionally delirium.

  • Superantigens

    • The immune system over-reaction to the antigen causes a group of diseases that manifest in fever and shock, such as food poisoning, toxic shock syndrome, and Kawasaki disease.
    • The large number of activated T-cells generates a massive immune response which is not specific to any particular epitope on the SAg.

  • Classic Viral Hemorrhagic Fevers

    • All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases.
    • The family Arenaviridae include the viruses responsible for Lassa fever, Lujo virus, Argentine, Bolivian, Brazilian and Venezuelan hemorrhagic fevers.
    • Manifestations of VHF often also include flushing of the face and chest, petechiae, frank bleeding, edema, hypotension, and shock.