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.