BIOM 250n 1st Edition Lecture 13Outline of Last Lecture I. Disease StagesII. ReservoirIII. Transmission of DiseaseIV. Disease VectorsV. Nosocomial Infection VI. EpidemiologyVII. Microbial PathogenicityVIII. Adherence IX. InvasionX. ToxinsOutline of Current Lecture I. Membrane-Disrupting ToxinsII. SuperantigensIII. EndotoxinsIV. Plasmids and Lysogeny Current LectureI. Membrane-Disrupting Toxinsa. Membrane disrupting toxins lyse host cells by:i. Forming protein channels in the plasma membraneii. Disrupting the phospholipid bilayerb. Leukocidins kill white blood cells (leukocytes)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Hemolysins kill red blood cells (erythrocytes)d. Streptolysins lyse both blood cell typesII. Superantigens a. Antigens that induce very powerful immune responsei. An antigen is any substance that can cause the production of an antibodyii. an antibody is a protein that can bind to an antigenb. Superantigens stimulate an increase in the number of T-cellsi. T-cells are leukocytes that can signal immune system activation or suppression c. T cells release cytokinesi. Cytokines: soluble proteins responsible for induction of an immune responsed. Staph aureus can release a superantigen—which causes toxic shock syndromeIII. Endotoxins a. Lipid A component of outer cell wall of a gram negative bacteriab. Released when cells die or are killed by antibioticsc. Stimulates macrophages to produce cytokinesd. Symptoms from endotoxins include: chills, fever, aches, and potentially severe shock/deathi. Shock is defined as low blood pressuree. Endotoxic shock:i. Phagocytosis of gram negative bacterium releases a tumor necrosis factor(TNF)ii. TNF increases the permeability of blood vessels—makes them more leakyiii. Low blood pressure leads to shock which has damaging results to many organsf. Poor antitoxin formation against endotoxinsIV. Plasmids and Lysogenya. Plasmids can carry genes for pathogenicityi. Uptake of plasmid can causes bacterium to produce a toxinb. Bacteriophages can also carry toxin genesi. Phage is a bacterial virusii. Some cause cell lysis which destroys the cell and releases the virusiii. Some are lysogenic and insert genes into the bacterial chromosomeiv. Lysogenic phage change some bacteria to
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