Chapter 14 micro notes

Chapter 14 micro notes - Micro notes Microbes can colonize...

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Micro notes Microbes can colonize only nutrients that can supply the appropriate nutrients Although the bodily defenses are extremely important against pathogens, their role in determining and regulating the normal microbiota is unclear. Certain regions of the body are subjected to mechanical forces that may affect colonization by the normal microbiota. Microbes are not absolutely essential to animal life, but lab grown germ free animals have underdeveloped immune systems and are unusually susceptible to infection a serious disease. Germ free animals also require more calories and vitamins than do normal animals. Pathology is the scientific study of disease (pathos-suffering; logos-science) Etiology- the cause of a disease Pathogenesis- the manner in which a disease develops. Infection- invasion or colonization of the body by pathogenic microorganism Disease- any change in the state of health resulting from an infection Normal microbiota (flora)- the organisms that normally reside in the human body but do not produce disease under normal conditions Transient microbiota- may be present for several days, weeks, or months then disappear Microbial antagonism / competitive exclusion – the normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms. The adult human vagina maintains a local pH of about 4 E. coli cells produce bacteriocins, proteins that inhibit the growth of other bacteria such as pathogenic salmonella and shigella Bacteriocins are used in medical microbiology to help identify different strains of bacteria. Clostridium difficile in the large intestine are inhibited by normal microbiota by making host receptors unavailable, competing for available nutrients, or producing bacteriocins. This microbe is responsible for nearly all gastrointestinal infections that follow antibiotic therapy from mild diarrhea to severe or even fatal colitis. Symbiosis- a relationship between two organisms in which at least one organism is dependent on the other. Commensalism- a symbiotic relationship where one of the organisms benefits and the other is unaffected. This includes the cornyebacteria that inhabit the surface of the eye and certain saprophytic (feeds on dead organic matter) mycobacteria that inhabit the ear and external genitals.
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Mutualism- A type of symbiosis that benefits both organisms. For example, the large intestine contains contains some bacteria, such as E. coli that synthesize vitamin K and some B vitamins. Probiotics- live microbial cultures applied to or ingested that are intended to exert a beneficial effect. Prebiotics- chemicals that select for growth of beneficial bacteria. Under certain conditions, the symbiotic relationship of normal microbiota can change, for example E. coli is harmless as long as it stays in the large intestine.
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This note was uploaded on 05/04/2011 for the course BIOL 2421 taught by Professor Allen-mierl during the Spring '11 term at Austin Community College.

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Chapter 14 micro notes - Micro notes Microbes can colonize...

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