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This Concept Map, created with IHMC CmapTools, has information related to: Answers_QS, Formation of biofilms. advantages Adhere to environmental surfaces and resist flushing, The production, release, and community-wide sensing of molecules called autoinducers that modulate gene expression in response to the density of a bacterial population interspecies communication Communicating with bacteria that are not of their genus and species., Most of the virulence factors that enable bacteria to colonize the body and/or harm the body are the products of quorum sensing genes. Many bacteria are able to sense their own population density, communicate with each other by way of secreted chemical factors, and behave either as individual bacteria or as a population of bacteria. virulence factors Molecules expressed and secreted by that enable them to colonize the host, evade or inhibit the immune responses of the host, enter into or out of a host cell, and/or obtain nutrition from the host., The production, release, and community-wide sensing of molecules called autoinducers that modulate gene expression in response to the density of a bacterial population function in virulence Most of the virulence factors that enable bacteria to colonize the body and/or harm the body are the products of quorum sensing genes. Many bacteria are able to sense their own population density, communicate with each other by way of secreted chemical factors, and behave either as individual bacteria or as a population of bacteria., Formation of biofilms. advantages Resist phagocytosis and attack by the body's complement pathways, Aspects of Bacterial Genetics that are Directly Related to Bacterial Pathogenicity pathogenicity islands PAIs Pathogenic bacteria often show extra genes coding for virulence factors, that is, molecules expressed and secreted by the bacterium that enable them to colonize the host, evade or inhibit the immune responses of the host, enter into or out of a host cell, and/or obtain nutrition from the host., By behaving as a multicellular population, individual bacteria within a group are able to benefit from the activity of the entire group. As the entire population of bacteria simultaneously turn on their virulence genes, the body's immune systems are much less likely to have enough time to counter those virulence factors before harm is done. examples Producing enzymes and toxins to enable bacteria to obtain nutrients from host cells., Once P. aeruginosa is able to replicate and achieve a high population density, quorum sensing leads to activation virulence genes coding for exoenzyme, toxins, and formation of a biofilm. secreting an adhesive matrix Biofilm formation, type 3 secretion system function Enables the bacterium to directly inject bacterial effector molecules into the cytoplasm of the host cell in order to alter its cellular machinery or cellular communication., The autoinducers diffuse away from the bacteria. Sufficient quantities of these molecules are unable to bind to the signaling\receptors on the bacterial surface and the quorum sensing genes that enable the bacteria to act as a population are not activated. This enables the bacteria to behave as individual, single-celled organisms. advantages of individual bacterial behavior Acting as individual organisms may better enable that low density of bacteria to gain a better foothold in their new environment., Pathogenicity and virulence are terms that refer to an organism's ability to cause disease. virulence The degree of pathogenicity within a group or species of microbes., Once P. aeruginosa is able to replicate and achieve a high population density, quorum sensing leads to activation virulence genes coding for exoenzyme, toxins, and formation of a biofilm. enzymes/toxins Enables the bacteria to get nutrients from damaged host cells., By behaving as a multicellular population, individual bacteria within a group are able to benefit from the activity of the entire group. As the entire population of bacteria simultaneously turn on their virulence genes, the body's immune systems are much less likely to have enough time to counter those virulence factors before harm is done. examples Formation of biofilms., Pseudomonas aeruginosa causes severe nosocomial infections, chronic infections in people with cystic fibrosis, and potentially fatal infections in those who are immunocompromised. multicellular bacterial behavior Once P. aeruginosa is able to replicate and achieve a high population density, quorum sensing leads to activation virulence genes coding for exoenzyme, toxins, and formation of a biofilm., Aspects of Bacterial Genetics that are Directly Related to Bacterial Pathogenicity pathogenicity islands PAIs Most genes coding for virulence factors in bacteria are located in pathogenicity islands or PAIs and are usually acquired by horizontal gene transfer involving conjugative plasmids., When P. aeruginosa first enters the body, motility genes coding for flagella, and adhesin genes coding for pili and cell wall adhesins are expressed. type IV pili As the bacteria begin to replicate, type IV pili enable the bacteria, by way of twitching motility, to crawl along the surface of the mucous membranes and spread out., Most of the virulence factors that enable bacteria to colonize the body and/or harm the body are the products of quorum sensing genes. Many bacteria are able to sense their own population density, communicate with each other by way of secreted chemical factors, and behave either as individual bacteria or as a population of bacteria. low density of bacteria The autoinducers diffuse away from the bacteria. Sufficient quantities of these molecules are unable to bind to the signaling\receptors on the bacterial surface and the quorum sensing genes that enable the bacteria to act as a population are not activated. This enables the bacteria to behave as individual, single-celled organisms., The production, release, and community-wide sensing of molecules called autoinducers that modulate gene expression in response to the density of a bacterial population intraspecies communication Communicating with members of their own species., type 6 secretion system function Not only injects effector molecules into eukaryotic cells, but also is able to inject antibacterial effector molecules into other bacteria in order to kill those bacteria., Pathogenicity and virulence are terms that refer to an organism's ability to cause disease. pathogenicity The ability of a microbe to cause disease and inflict damage upon its host.
