Microbiology is the study of microorganisms too small to be seen without a microscope. Microbes are found everywhere and play important roles in ecosystems and human bodies. While most microbes are harmless or beneficial, some can cause disease. Key figures like van Leeuwenhoek first observed microbes, Pasteur disproved spontaneous generation and established germ theory, Koch linked specific microbes to diseases, Jenner developed the first vaccine, Fleming discovered penicillin, and advances now help detect, treat, and prevent infectious diseases.
2. Microorganisms (microbes) What are microorganisms? - Very small organisms that usually need to be seen with a microscope. - Microbes are ubiquitous- They are EVERYWHERE!!! In terms of range of distribution & numbers, microbes are the dominant organisms on earth. - Most microbes on earth are NOT harmful to humans- in fact, they are very important parts of the world’s ecosystems. - Those microbes that can harm humans are calledpathogenic (disease causing) Microbiology studies: Bacteria, Viruses, Protozoa, Algae, Fungi (yeasts & molds) Helminths (parasitic worms)
3. Origins of Microorganisms Fossil records show bacteria-like organisms about 3.5 billion years ago! These fossils are the 1st evidence of life on earth. These simple cells are calledprokaryotic. (before nucleus). Bacteria have these prokaryotic cells and are therefore called prokaryotes. Prokaryotic cells then gave rise to a more complex type of cell that we call a eukaryotic cell (with true nucleus). All other forms of life have eukaryotic cells, we can call them eukaryotes. Eukaryotic organisms include animals, plants, fungi & protists. Deep sea vents & origins of life
4. Microbiological fields Microbiology: the study of many areas- cell structure, function, genetics, immunology, biochemistry, epidemiology & ecology. Bacteriology: study of bacteria Mycology: study of fungi (medical, agricultural, ecological) Parasitology: study of protozoa & parasitic worms Immunology: study of immune system, vaccine, allergy, blood testing Virology: study of viruses Epidemiology: study of public health: cause, distribution and control of disease in human populations. Biotechnology: altering microorganisms genetic material Microbial ecology: relationship between microbes & environment, recycling nutrients in soil, water. Food, dairy, aquatic, agricultural, astromicrobiology! Etc! etc!
5. Microbes are important part of life on earth! Recycle vital elements: Bacteria & fungi decompose matter into its elements to be used again. (greenhouse gas composition largely by gasses from microbes, soil composition etc.) 2. Symbiotic relationships with plants & animals. Microbes that live on/in other organisms are beneficial. 3. Sewage treatment: human waste, waste water, industrial waste, surface runoff. Treatment with chemical & bacteria. 4. BioremediationSome microbes can remove toxic substances from underwater wells, toxic spills, waste water, oil spills. 5. Insect pest control: bacteria & fungi can be used to control insect population that destroys crops. Better than pesticides that stay in soil & toxins get incorporated into food web. Eg) locusts & mold 6. Biotechnology:genetic engineering manipulates DNA of microbes, plants & animals. (plants resistant to pesticides, yeast that produce human proteins, pigs that make human hemoglobin etc. 7. Basis of food chain: Maintain ecological balance in marine and land life.
6. Microbes & our bodies Normal microbiotaOR normal flora are microorganisms that normally live on & inside our bodies. Functions: A) Our normal flora is important to our health! “The bacteria living in our digestive tract have been shown to help digestion, protect against infection, and aid the development of the intestine after birth.” Harvard newsletter B) Our normal flora creates an environment in which not one microbe will overgrow to cause problems. C) Normal flora makes it more difficult for pathogenic bacteria to colonize our bodies. D) Problems may arise when normal flora is killed off. Eg) women: yeast infection common when taking antibiotics
7. Taxonomy is the formal filing system used to classify living organisms by phylogenetic similarity which is based on evolutionary similarities in morphology, physiology & genetics. All living things belong to one of three domains: Bacteria, Archaea & Eukarya. (2 domains consist of only bacteria!) D. Bacteria: contain all “everyday” bacteria D. Archaea: contains all “extreme” bacteria video- geomicrobiologists D. Eukarya: contains everything else! (animals, plants, protists, fungi)
9. Scientific Nomenclature- Binomial system ● All scientific names for organisms are written using the binomial system written as: Genus species. ● Genus capitalized, species is lower case. ● In italics or underlined. Examples: Staphylococcus aureus Abbreviated to S. aureus Name can be descriptive: Staphylococcus epidermidis After the disease the organism causes: Mycobacterium tuberculosis According to who discovered it: Escherichia coli
10. History of Microbiology Up until the middle 1600’s people believed that living things can arise from non-living matter.This was called spontaneous generation, orabiogenesis. Without the knowledge of microscopic organisms (eggs, bacteria, larvae, etc) or the help of a microscope, people did not know what causes matter to rot, spoil, mold or how people got sick! Eg) Jan Baptista van Helmont’s recipe for mice: Place a dirty shirt or some rags in an open pot or barrel containing a few grains of wheat or some wheat bran, and in 21 days, mice will appear. There will be adult males and females present, and they will be capable of mating and reproducing more mice.
11. History of Microbiology Antoni van Leeuwenhoek “Father of Microbiology” Man obsessed with milling glass lenses. 1683: first to observe living organisms w/ magnifying lens. Took samples from rain water & teeth scrapings (people in these days almost never brushed their teeth!) Saw moving organisms he called “animalcules”, which were probably bacteria & protists. There was no knowledge of any microscopic organism before this & discovery of small living things prompted much research into this area. He was then recognized as a scientist by the Royal Society of London. 1753
12. History of Microbiology 1861 Louis Pasteur was an acclaimed microbiologist. Had been studying roles of microorganisms in the fermentation of beer & wine and how they can spoil. Until now, people thought that air converted sugar to alcohol. Pasteur found that yeast was responsible for fermentation & other organismscauses spoiling. Solution: raising the temperature of beer and wine so that bacteria are killed off. Now known as pasteurization! Monsieur Louie, why is our wine and beer spoiling?
13. Disproving spontaneous generation Louis Pasteur was certain that microorganisms werepresent in the air & could contaminate things. He performed a series of careful experiments which proved that organisms such as bacteria and fungi do not appear in liquid broths on their own, but the liquid must be contaminated with microbes found in the air.
14. Pasteur’s experiment Two sets of broths in flasks with S-shaped necks are boiled to sterilize liquid. Pasteur breaks off one of the necks to allow dust to travel down into flask. S-shaped neck traps dust & microbes on dust by gravity before they get to broth. Results: The open neck bottle was contaminated & grew microbes. S-shaped flask remained microbe free. Heating to kill all organisms Sterile broth Germs from air Germs trapped Re-infected Sterile
15. History of Microbiology Robert Koch His experiment linked microorganism to a specific disease! Before this time, it was known that microbes can “spoil” things, but the idea that they caused human disease was still new. Isolated Bacillus anthracisin infected animals & found that this bacteria causes anthrax disease. “Koch’s postulates” used today. Sequence of steps to relate a specific microbe to a specific disease.
16. Koch & Pasteur’s work Discovery of microbes in the air and that germs cause diseases in humans lead a surgeon (Joeseph Lister) to come up with aseptic techniques, aimed at reducing microbes in the hospital & need for sanitizing things. Surgeons began washing hands and using disinfectants! Before this, Dr would come from an autopsy and deliver a baby without washing his hands! Lots of women got infections this way. Pasteur’s experiments & Robert Koch confirmed the germ theory of disease. The germ theory of disease states thatmicroorganisms cause disease & infection!
17. History of Microbiology (1796) Edward Jenner Found milkmaids didn’t contract smallpox if they had contracted cowpox earlier. Jenner took cowpox lesions & inoculated a healthy boy. Later, he took smallpox lesion from sick person & inoculated the same boy. Boy did not come down with smallpox! This method was called “vaccination” from vacca (cow) in Jenner’s honor.
18. History of Microbiology 1928 Alexander Fleming Discovered the first antibiotic. Before this time, there was no cure for bacterial infections. People died from common bacterial infections. Discovered a mold could inhibit bacterial growth. The mold wasPenicilliumnotatum Today’s penicillin!
19. Why are diseases changing/emerging ? Ecological changes: deforestation, warming of oceans, drought, flood, etc. eg) malaria increase due to deforestation in South America Animal populations that harbor diseases are strongly influenced by environmental changes. In raising animals for food: types of feed, antibiotics, living conditions all affect animal health & spread of disease. Evolutionary/genetic changes in microorganisms: multi-drug resistant bacteria, mutating viruses etc. People misusing antibiotics, not finishing their course of antibiotics cause “super bugs”.
20. Population increase: Now world pop’l 6.5 billion. Estimated to reach 9.5 billion in 2050. Congested cities, people closer together, more poverty, less clean resources (clean water!) more stress on sanitation needs etc. World travel: People (and their diseases) are no longer isolated to certain regions. Eg) West Nile came from Uganda, Hanta virus first discovered in Korea. Migrating animals, pests hitch a ride on planes, people bringing in exotic plants & fruit carry microorganisms.
21. Advances of microbiology AIDS drugs (fatal to chronic disease) Gene therapy research hopes to treat SCID, muscular dystrophy, cystic fibrosis, genetic hypercholesterolemia. New tests for early detection for diseases: such as BSE blood test. New vaccines & eradicating disease from populations. New anti-viral & anti-bacterial medications being researched. Advances in food & water microbiology makes food preservation possible. Microbes and human welfare: Rx for survival
22. Quiz yourself 1) Which one of the following is NOT a microorganism? A) virus b) bacteria c) protozoan d) mushroom 2) An area of microbiology that is concerned with the occurrence of disease in human populations is: a) Immunology c) parasitology b) Epidemiology d) bioremediation 3) Which process involves the deliberate alteration of an organisms genetic material? a) Bioremediation c) biotechnology b) decomposition d) biotechnology 4) Which choice of taxonomic groups will allow the most diverse amount of organisms in it? a) Phyla b) class c) species d) order e) family
23. Abiogenesis refers to the: a) spontaneous generation of organisms from nonliving matter b) development of life froms from preexisting life forms c) development of aseptic techniques d) germ theory of disease Which of the following are prokaryotic? a) bacteria b) archaea c) protists d) both a and b 7. Which early microbiologist(s) were most responsible for disproving spontaneous generation? For making the first vaccine? For stopping the spoiling of alcoholic beverages? For discovering an antibiotic? For linking a microbe to a disease? For first seeing microorganisms? a) Leewenhook b) Koch c) Pasteur d) Jenner e) Flemming
