Sandbox WWC6: Difference between revisions
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== Function == | == Function == | ||
Hemolysins are most commonly proteins found in red blood cells that allow for the rapid release of small molecules and ions across the membrane. <ref >https://en.wikipedia.org/wiki/Hemolysin#cite_note-pmid20692229-3</ref> or lipid biosurfactants that disrupt membrane composition resulting in cell lysis. Hemolysins act through disruption of the cell membrane. <ref>http://www.sciencedirect.com/science/article/pii/S0005273610002610</ref> Pore formation | Hemolysins are most commonly proteins found in red blood cells that allow for the rapid release of small molecules and ions across the membrane. <ref >https://en.wikipedia.org/wiki/Hemolysin#cite_note-pmid20692229-3</ref> or lipid biosurfactants that disrupt membrane composition resulting in cell lysis. Hemolysins act through disruption of the cell membrane. <ref>http://www.sciencedirect.com/science/article/pii/S0005273610002610</ref> Pore formation is the olgomerization of the pore sunbunits within the membrane. The pore is quickly filled with water, ions, and small molecules that rapidly exit the cell, dissipating ionic gradients and membrane potential. Osmotic pressure causes a rapid swelling of the cell, leading to total rupture of the membrane <ref>http://www.ks.uiuc.edu/Research/hemolysin/<ref>. These proteins are important for some erythrocyte nutrient accession, but cause massive erythrocyte destruction in bacterial infection, specifically responsible forhemolytic anemia, which causes fatigue, pain, arrythmias, and even heart failure in affected individuals. <ref>http://www.nhlbi.nih.gov/health/health-topics/topics/ha/</ref> | ||
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==Pathogenic microorganisms== | ==Pathogenic microorganisms== | ||
Pore-forming toxins have been shown to closely relate to the pathogenicity of the toxin-producing organism <ref>http://www.ncbi.nlm.nih.gov/pubmed/1930675<ref> Both gram positive and gram negative bacteria are producers of hemolysins, as well as some clinically relevant fungi. Toxin secretion facillitates the availability of water, ions, and small molecules like sugar for the secreting pathogen. Hemolysin producing pathogen are identified by their ability to lyse cells in vitro <ref>https://en.wikipedia.org/wiki/Hemolysin<ref> | Pore-forming toxins have been shown to closely relate to the pathogenicity of the toxin-producing organism. <ref>http://www.ncbi.nlm.nih.gov/pubmed/1930675<ref> Both gram positive and gram negative bacteria are producers of hemolysins, as well as some clinically relevant fungi. Toxin secretion facillitates the availability of water, ions, and small molecules like sugar for the secreting pathogen. Hemolysin producing pathogen are identified by their ability to lyse cells in vitro. <ref>https://en.wikipedia.org/wiki/Hemolysin<ref> | ||
==Mechanism== | ==Mechanism== | ||
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{{Template:ColorKey_Polar}} | {{Template:ColorKey_Polar}} | ||
===Pore formation=== | ===Pore formation=== | ||
Pore formation of hemolysins is believed to be a conserved process | Pore formation of hemolysins is believed to be a conserved process across subtypes. <ref>http://www.nature.com/ncomms/2014/140929/ncomms5897/full/ncomms5897.html<ref> | ||
Studies suggest that pore formation is achieved through a nonlytic intermediate oligomer, known as a prepore. The prepore model proposal suggests that the monomeric components assemble on the cell membrane surfacte into a prepore with prestem subunits packed inside. The formed prepore then goes through a conformational change prestem, forming the β-barrel pore. Several issues with the proposed pore formation mechanism have been identified including steric hindrance of the packed prestem structure. | Studies suggest that pore formation is achieved through a nonlytic intermediate oligomer, known as a prepore. The prepore model proposal suggests that the monomeric components assemble on the cell membrane surfacte into a prepore with prestem subunits packed inside. The formed prepore then goes through a conformational change prestem, forming the β-barrel pore. Several issues with the proposed pore formation mechanism have been identified including steric hindrance of the packed prestem structure. | ||
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===Oncology=== | ===Oncology=== | ||
Thermostable direct hemoslysin (TDH) is one type of hemolysin, secreted by ''Vibrio parahaemolyticus'', that may be linked to the down regulation of | Thermostable direct hemoslysin (TDH) is one type of hemolysin, secreted by ''Vibrio parahaemolyticus'', that may be linked to the down regulation of colon carcinoma cell proliferation. <ref>http://www.sciencedirect.com/science/article/pii/S030441651200116X<ref> | ||
===Hemolytic anemia=== | ===Hemolytic anemia=== | ||
Hemolytic anemia occurs when lysis of red blood cells occurs are rates faster than they can be replaced by bone marrow. <ref>https://www.nhlbi.nih.gov/health/health-topics/topics/ha<ref> | Hemolytic anemia occurs when lysis of red blood cells occurs are rates faster than they can be replaced by bone marrow. <ref>https://www.nhlbi.nih.gov/health/health-topics/topics/ha<ref> | ||
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