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Biology 318Introduction to Microbiology
MicrobiologyThe study of small living
thingsCells - Bacteria, Algae,
Protozoa, FungiNot Cells - Viruses and
PrionsAll are UBIQUITOUS
Prokaryotic CellsSimpler, smaller, and the most primitiveInclude Eubacteria - 3% disease, a.k.a. BacteriaInclude Archaea - extreme habitats, no disease
Eukaryotic CellsMore complex, larger, and modernInclude Algae, Protozoa, Fungi, Animals, Plants
Penicillium
Viruses and PrionsAll are infectious pathogensNot made of cells
Microbiology Is Far-Reaching and Beneficial
Sub-Disciplines of MicrobiologyMedical and VeterinaryAgricultureWaste ManagementIndustrial Biotechnology Basic Research and GeneticsEnvironmental
Waste ManagementSoil bacteria and fungi - decomposersMany perform bioremediation - consume toxinsWater treatment, composting, landfills (produce
methane)
Industrial and Biotechnology Products
Vitamins and essential amino acids in the gut
Soured foods and alcohol - food preservation
Medical tools - antibiotics and vaccines
Genetic engineering -cloning tools
Nitrogen FixationOnly some bacteria capture nitrogen from airConvert it to parts of proteins and DNABasis for crop rotation, biological fertilizers
Indigenous Microflora or Normal Flora Natural inhabitants of or on the body (1011) 10 TIMES more of them than your own cellsEither beneficial OR have no effect
Microbes and Medicine
PathogenMicrobes that cause diseaseOnly 3% of known microbes are pathogens
Infectious Diseases
50,000 people per day die from these24 million people per year die from these40% third world deaths4% first world deaths
Opportunistic PathogenCause disease given the opportunity“wrong place” or “wrong time”Some normal flora can become opportunists
Infectious Diseases
B.C. MicrobiologyEgypt, Greece, ChinaHygiene standardsUnderstood transmissionPrimitive vaccinesPracticed biowarfare
Biblical Laws and Public HealthLeviticus refers to personal hygiene practicesDefines public waste managementProhibits eating animals that died naturally
Middle AgesCultural stagnation and crowding - epidemicsSmallpox, syphilis, plague, rabies…People believed diseases were acts of GodBizarre and illogical treatments
Spontaneous GenerationFalse idea spawned in Middle AgesSaid that life could arise from non-living thingsMaggots from meat, spoilage for no reason
Anton van Leewenhoek (1600s)Built microscopes (300X) - saw first microbesPepper water, tooth plaque, gutter water, fecesAlso saw cells in semen, urine, and blood
Redi’s Experiments
Louis Pasteur (1800s)
Alcohol fermentation and anaerobic metabolism
Disproved Spontaneous Generation
Decontamination standards -Pasteurization
Improved hospital practices to reduce disease
Developed many early vaccines
Downfall of Spontaneous GenerationMilk, broth, beer/wine did not spoilIf heated to 50-70°C for 15 minutesPasteurization - decontamination
Robert Koch (1800s)
Germ Theory of Disease and Koch’s Postulates
Isolated anthrax, TB, and cholera bacteriaDeveloped fixing and staining methodsWith colleagues, developed media and
toolsDeveloped skin test for TB - immunology
Germ Theory of DiseaseDiseases do not come from nothingSpecific diseases are caused by specific agentsFirst link - Bacillus anthracis and anthrax
Koch’s PostulatesAgent detected ONLY in diseased individualsIsolated in pure culture outside hostPure isolates cause disease in test animals Same agent re-cultured from test animals
Modern Exceptions to Koch’s PostulatesMany agents do not grow outside living cellsNot all agents cause disease in animal hostsMany diseases are asymptomatic Some diseases involve more than one agentSome diseases not caused by microorganismsSome diseases involve more than one agentDetection now includes antibodies and DNA
HIV/AIDS REQUIRES that we use and accept many of these modern exceptions.