MCB2004 Exam 3 Review Guide 4 1 15 Lecture 17 18 Bacteria Summary I 1 The three domain system a Archaea i Prokaryotic no peptidoglycan membrane lipids composed of branched carbon chains attached to glycerol by ether linkage not antibiotic sensitive lack rRNA loop i Prokaryotic contains peptidoglycan membrane lipids composed of straight carbon chains attached to glycerol by ester linkage sensitive to antibiotics present rRNA loop b Bacteria c Eukarya i Eukaryotic CHO cell wall membrane lipids composed of straight carbon chains attached to glycerol by ester linkage not sensitive to antibiotics lack rRNA loop Cell type Cell wall Membrane lipids Antibiotic sensitivity rRNA loop Archaea Prokaryotic No peptidoglycan Branched carbon chains attached to glycerol by ether linkage No Lacking Bacteria Prokaryotic Peptidoglycan Straight carbon chains attached to glycerol by ester linkage Yes Present Eukarya Eukaryotic Contain CHO Straight carbon chains attached to glycerol by ester linkage No Lacking 2 Characteristics of bacteria Gram negative and gram positive a Peptidoglycan cell walls b Ester linked lipids mostly phospholipids c 70S ribosomes d Genomes are single circular ds DNAs e Genome range 585 9450 kbp f Operons are common g Many have plasmids and transposons i Plasmids small DNA molecule within the cell that is physically separated from a chromosomal DNA and can replicate independently ii Transposons small piece of DNA that inserts itself into another place in the genome 3 The alphaproteobacteria a Mainly plant microbes b Plant pathogen argobacterium i Insert a plasmid into plant cells introducing a tumor An important tool for transgenic plants c Rhizobium fix nitrogen in the roots of plants d Obligate intracellular parasites i Rickettsia 1 Anthropod borne 2 Mitochondria appear to be descendants of ancient rickettsia parasites 4 The betaproteobacteria a Neisseria meningitis gonorrhoeae b Bordetella pertussis i Rods ii Pertussis cause of whooping cough c Spirillum i Helical 5 The gammaproteobacteria a Enterics E coli salmonella shigella Yersinia black death i Peritrichous flagella facultatively anaerobic b The vibrios c Haemophilus i Found in coastal water causes cholera i Require X and V factors NAD and NADP d Pseudomonas opportunistic i Metabolically diverse ii Polar flagella e Legionella Coxiella Francisella i Found in streams water etc ii Intra cellular parasite transmitted by aerosols or milk 6 The deltaproteobacteria i Prey on other bacteria 7 The low GC gram positive bacteria a Gram positive thick peptidoglycan cell wall teichoic acids b The bacillus class i Bacillus anthracis thuringiensis aerobic spore formers ii Streptococcus many pathogens iii Staphylococcus aureus 1 Produce endotoxin common cause of food poisoning iv Listeria monocytogenes 8 Clostridial class obligate anaerobic spore formers a C botulinism causes botulinism b C tetani causes tetanus 9 The wall less bacteria mycoplasma a smallest genomes 10 The high GC gram positive bacteria a Actinomyces b Streptomyces i Filamentous forms i Many soil bacteria rich smell of soil due to Streptomyces c Mycobacterium and other acid fast bacteria 11 Chlamydia obligate intracellular parasites life cycles associated diseases a Life cycles i Bacterium s infectious form the elementary body attaches to a host cell ii The host cell phagocytizes the elementary body housing it in a vacuole iii The elementary body reorganizes to form reticulate body iv The reticulate body divides successfully producing multiple reticulate bodies v The reticulate bodies begin to convert back to elementary bodies vi The elementary bodies are released from the host cell 12 Spirochaetes axial filaments treponema pallidum syphilis borrelia burgdorferi lyme disease a Spiral organisms with a sheath and axial filaments b Slow growing aquatic free living or parasitic 13 Microbial Diversity a PCR indicates 10 000 bacteria per gram of soil b Many bacteria haven t been identified because they haven t been cultured need special ingredients are a part of complex food chains requiring the products for other bacteria need to be cultured to understand their metabolism and ecological role Lecture 19 Principle of disease and epidemiology 14 Terminology 15 Normal microbiota and the host a Normal microbiota permanently colonize the host b Transient microbiota may be present for days weeks or months c Normal bacteria protect the host by occupying niches that pathogens might occupy producing acids producing bacteriocins 16 Symbiosis three relationships a Mutualism both organisms benefit b Commensalism one organism benefits the other is unaffected c Parasitism one organism is benefitted at the expense of the other 17 Koch s postulates and exceptions a Postulates i Same pathogen must be present in every case of the disease ii The pathogen must be isolated from the diseases host and grown in pure culture iii The pathogen from the pure culture must cause the disease when it is inoculated into a healthy susceptible lab animal iv The pathogen must be isolated from the inoculated animal and must be shown to be the original animal b Exceptions i Some pathogens can cause several disease conditions or the same pathogen can cause different disease symptoms ii Some pathogens can cause disease in only humans iii Some pathogens need cofactors iv Development of some disease takes years 18 Types of infectious diseases a Noncommunicable b Communicable c Contagious disease 19 Predisposing factors 20 Transmission of diseases a Contact a Continual sources of infection human animal nonliving b Pandemic worldwide epidemic c Epidemic disease acquired by many hosts in a given area in a short period of time d Endemic disease constantly present in a population i Direct close association between infected and susceptible host ii iii Droplet airborne droplets Indirect fomites i Transmission by an inanimate reservoir food water b Vehicle c Vectors i Arthropods fleas ticks mosquitoes ii Biological pathogen reproduces in vector 21 Epidemiology history key figures tools a Epidemiology study of diseases in populations i Occurrence distribution control and prevention John Snow cholera Ignaz Semmelweis puerperal fever b c d Florence Nightingale typhus 22 CDC WHO and their functions a Collects and analyzes epidemiological information the US i Morbidity rate number of people affected in relation to the total population in a given time period Lecture 20 Nosocomial infections and emerging infectious diseases EIDs
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