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Microbiology Unit One Review VOCABULARY Microorganisms: organisms that are too small to be seen with the unaided eye. Normal microbiota: microorganisms that are normally found on or in the body and do not cause disease. Germ: rapidly growing cell Pathogen: microbe that causes disease. Bacteriology: a study of bacteria. Mycology: a study of fungi. Parasitology: the study of protozoa, parasites, and warms. Immunology: a study of immunity. Virology: the scientific study of viruses. Biotechnology: the industrial application of microorganisms, cells, or cell components to make a useful product. Microbial ecology: the study of the relationship between microorganisms and their environment; originated from Beijerinck and Windogradskyi. Microbial genetics: study of the mechanisms by which microorganisms inherit traits. Microbial physiology: the study of the metabolism of microbes. Molecular biology: the science of dealing with DNA and protein synthesis of living organisms. Genomics: the study of an organisms genes; used to classify a microorganisms. Bio remediation: bacteria degrade organic matter in sewage. Bacteria also degrade or detoxify pollutants such as oil and mercury. Genetic engineering: a new technique for biotechnology. Bacteria and fungi can produce a variety of proteins including vaccines and enzymes. Taxonomy: the science of the classification of organisms. Spontaneous generation: the idea that life could arise spontaneously from nonliving matter. Biogenesis: the theory that living cells arise only from pre-existing cells. Probiotic: adding microbes to your diet. Nosocomial diseases: acquired in hospitals; an infection that develops during the course of a hospital stay and was not present at the time the patient was admitted. Neonate: newborn Immunocompromised: vulnerable to disease caused by normal microbiota. Fermentation: the enzymatic degeneration of carbohydrates in which the final electron acceptor is an organic molecule (contains carbon). For example, ATP is synthesized by phosporylation (adding phosphate) and oxygen it is not required. Fermentation is the process that yeasts use to convert sugars to alcohol in the absence of air. Pasteurization: the process of mild heating to kill particular spoilage microorganisms or pathogens. Anaerobic: without oxygen MICROORGANISMS Too small to be seen with the unaided eye. Decompose organic wastes. Are producers in the ecosystem by photosynthesis. These include plants, algae, fungi, and cyanobacteria only. Produce industrial chemicals such as ethanol (a solvent; solvents dissolve substances) and acetone. Produce fermented foods such as vinegar, cheese, bread, beer, wine, and other useful products. Produce products used in manufacturing (e.g. cellulose) and disease treatment (e.g. insulin from E. coli). A few microorganisms are pathogenic (cause disease). Knowledge of microorganisms allows humans to: Prevent food spoilage Prevent disease Understand aseptic technique to prevent contamination and medicine, surgery, and in microbiology labs. THE GERM THEORY OF DISEASE Louis Pasteur, while he was studying fermentation, found that microorganisms are what cause disease. KOCH’S POSTULATES OBSERVE: the same pathogen must be present in every case of the disease. ISOLATE: the pathogen must be isolated from the diseased host and grown in pure culture. INOCULATE: the pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal. RE-ISOLATE: the pathogen must be isolated from the inoculated animal and must be shown to be the original organism. MICROBIOLOGISTS Aristotle: Spontaneous generation: darkness + dampness + grain = mice. Linnaeus: established a system of scientific nomenclature. Each organism has two names; genus and specific epithet (species). Janssen: invented the compound microscope Galileo: improved both the microscope and telescope. Van Leeuwenhoek: first observation of life microorganisms in teeth scrapings, and rain water. Hooke: first observation of cells. Devised cell theory: all living things are composed of cells. Redi: demonstrated that maggots grew only in the meat in which the flasks were not covered. Virchow: cells arise from pre-existing cells; the beginning of the biogenesis (cell) theory. Agostino Bassi: showed that a silkworm disease was caused by a fungus. Ignaz Semmelwise: advocated midwives to wash their hands when going from one obstetric patient to another to prevent transmission of for puerperal fever. Pasteur: fermentation, pasteurization processes. Pasteur showed that microbes are in the air, rain, spoiled foods, and cause disease in animals. Discoveries included the relationship between microbes and disease, immunity, and anti-microbial drugs (Germ Theory of disease). His work led to the first vaccine (chicken cholera). He also invented the rabies vaccine. His evidence was proof of biogenesis; led to aseptic technique (by Lister) to prevent contamination in laboratory and medical procedures. Koch: Koch’s postulates, pure cultures; he proved that a bacterium causes anthrax and provided the experimental steps (Koch’s postulates) to prove that a specific microbe causes a specific disease. Lister: studied sewage in cattle fields; used phenol for aseptic surgery to disinfect and prevent surgical wound infections after looking at Louis Pasteur’s work. Jenner: invented the vaccine for small pox: he inoculated a person with the non-deadly cow pox virus. The person became protected from the deadly smallpox virus. He called this protection “immunity”. He then made the first “vacca” (vaccination) for cows. His work began when he saw milkmaids touching cows with lesions on their udders; milkmaids were not contracting smallpox. Ehrlich: developed first antibiotic drug: Salvarsan, to treat syphilis; coined the term "chemotherapy". Von Behring: Discovered diptheria antitoxin. Ross: discovered that mosquitoes transmitted malaria Metchnikoff: discovered phagocytosis of white blood cells when he observed a thorn in a starfish. He began the field of immunology and studied the immune response. Fleming: discovered the first antibiotic (penicillin). He discovered that Penicillium fungus killed Staphylococcus aureus, when he found a green mold growing on his Petri dish of bacteria. Chain and Florey: produced penicillin for large-scale manufacture during WWII. Lancefield: classification of Streptococcus. Griffith: found a “transformation principle” in bacteria, known as DNA today. Non-virulent streptococci (can’t cause disease) were formed into virulent strains. Watson and Crick: discovered the structure of the DNA molecule Jacob and Monod: discovered the role of messenger RNA in protein synthesis. Delbruck and Hershey: discovered the replication mechanism and the genetic structure of viruses. Tonegawa: antibody genetics Prusiner: discovered the disease-causing protein called a prion (smaller than a virus). SELECTED NOBEL PRIZES IN PHYSIOLOGY 1901 1902 1905 1908 1945 1952 1969 1987 1997 Behring Ross Koch Metchnikoff Fleming, Chain, Florey Waksman Delbruck, Hershey Tohegawa Prusiner diphtheria antitoxin malaria transmission TB bacterium phagocytosis penicillin streptomycin viral replication antibody genetics prions MICROSCOPY Immersion oil: keeps light from bending and allows lens to be refracted. Resolution: ability of two lenses to distinguish two points. Parfocal: focused in all lenses. Depth of field: how much of the background is in focus at the same time that the foreground is in focus. Refractive Index: a measure of the light-bending ability of a medium Numerical aperture: numerical aperture increases as depth of field decreases. Resolution power: limits the useful magnification of the microscope resolving ESSAY QUESTIONS Compare and contrast the seven major groups of microbes. Explain the debate over spontaneous generation, name the scientists involved in the debate, and describe their contributions, stating whether they were for or against the theory of spontaneous generation. List ten microbiology pioneers that we studied, and describe their contributions to microbiology. Differentiate among the brightfield, darkfield, dissecting, phase contrast, fluorescence, differential interference contrast, SEM, TEM, and scanning probe types of microscopes, including their purpose, function, or any advantages and disadvantages that we studied. Differentiate between eukaryotic and prokaryotic cells. Draw a picture of a typical prokaryotic cell and label it. Below your drawing, pick any five structures you drew and discuss the structure and function of each one. MICROBES COMPARISON CHART BACTERIA Prokaryotic Peptidoglycan cell walls Reproduced by binary fission Uses organic and inorganic chemicals or photosynthesis for energy Shapes are rod, coccus, spiral ARCHAEA Prokaryotic Lack peptidoglycan Live in extreme environments Include methanogens, extreme Halophiles (love salt), extreme thermophiles (love heat and cold) FUNGI Eukaryotes Cell walls have chitin Heterotrophes: use only organic chemicals for energy Molds and mushrooms are multicellular; consist of masses of mycelia, which are composed of filaments hyphae. Yeasts are unicellular MICROBES COMPARISON CHART PROTOZOA Eukaryotes Absorb or ingests organic compounds May be motile via pseudopods, cilia, or flagella ALGAE Eukaryotes Cell wall contain cellulose Uses photosynthesis for energy Produces oxygen and organic food for other species VIRUSES Non-cellular intracellular parasites; lives at the expense of host Contain either DNA or RNA surrounded by a protein coat May have an envelope Smallest of all microbes Replicates in living host cell Antibiotics do not work; requires antiviral agents HELMINTHES AND NEMATODES Eukaryotes Helminthes: parasitic flat worms and tapeworms Nematodes: parasitic roundworms Endoparasites: animals that live inside other animals through fecal contamination Microscopic stages of life cycle Parasite is in the bite of mosquito or bug; spreads infection in body Spontaneous Generation Theory Aristotle thought that the mice grew from the grain and hay, and he coined the term “Spontaneous generation” Virgil: bees grew from honey and that flies grew from meat. Redi: maggots in meat were caused by flies laying eggs; they only grew on the meat in which the jars were not covered. John Needham believed in spontaneous generation; boiled nutrient broth to kill all microbes, put a non-sterile cork in the flask, found that the broth grew microbes. Louis Pasteur: made a glass flask with an “S” shaped bend in it so that bacteria could not enter into it but air could get in. He placed chicken broth in the flask and boiled it so that it was sterile and observed that there was no bacterial growth in the broth. COMPARISON OF MICROSCOPES BRIGHTFIELD Dark objects are visible against a bright background. Light reflected off the specimen does not enter the objective lens Not for looking at live cells Maximum resolution is 0.2µm and maximum magnification is 2000x Stains are used on specimens DARKFIELD Light objects are visible against dark background Used for live cells, cilia, flagella Especially good for spirochetes Uses special condenser with an opaque disc that eliminates all light in the center PHASECONTRAST No staying required Accentuates diffraction of the light that passes through a specimen Good for live cells; good contrast Most sensitive; cilia shows up Not three-dimensional DIFFERENTIAL Uses two beams of light INTERFERENCE Shows three dimensions CONTRAST Has a prism to get different colors Good for live cells (unstained) Best resolution COMPARISON OF MICROSCOPES FLUORESCENCE Uses ultraviolet light Stained cells with fluorescent dye; energizes electrons and creates visible light No live cells Quick diagnosis of TB and syphilis TRANSMISSION ELECTRON Get flat images Have vacuum pumps to allow electrons to float better Stain with heavy metal salts Shows sections of cell, revealing organelles Requires an ultramicrotome Best resolution SCANNING ELECTRON Surface view only Needs a vacuum No live cells Three-dimensional view SCANNING PROBE Physical probe scans the specimen Raster scan: image is cut up into pixels and transmitted to computer Not limited by diffraction Slower in acquiring images Maximum image size is smaller EUKARYOTIC PROKARYOTIC One circular chromosome, not membrane-bound Paired chromosomes, membrane-bound No histones Histones present No organelles Organelles present: Golgi complex, ER, mitochondria, chloroplasts Peptidoglycan cell walls Polysaccharide cell walls Reproduce by binary fission Reproduce by mitosis No true nucleus; no nuclear membrane True nucleus; nuclear membrane; also has nucleoli Glycocalyx present as capsule or slime layer Present in some cells that lack a cell wall Plasma membrane has no carbohydrates and lack sterols Plasma membrane has carbohydrates and sterols No cytoskeleton Has a cytoskeleton Ribosomes are small (70S) Ribosomes are large (80S) Prokaryotic Cell Drawing Structure and Function of Prokaryotic cells PLASMA MEMBRANE CELL WALL GLYCOCALYX CAPSULE SLIME LAYER FLAGELLUM SEX PILUS FIMBRAE PLASMA MEMBRANE Consists of a phospholipid bilayer, peripheral and integral proteins, and transporter proteins. Function: selectively permeable; allows for passage of only certain molecules. Gram negative organisms also have an outer plasma membrane with LPS, which is an antigen and contains a toxin. CELL WALL Composed of peptidoglycan, which is a series of two sugars, NAM and NAG, connected with a peptide (or protein) bond. Function of cell wall: provides rigidity and protection from osmotic lysis. GLYCOCALYX A sticky coating external to the cell wall, made of polysaccharide, polypeptide, or both. Made inside of the cell and secreted to the cell surface. May be either a capsule (organized) or a slime layer (not organized). Capsule function: to protect from phagocytosis. Slime layer function: allows for attachment to host. FLAGELLUM Made of a protein called flagellin. Consists of a basal body, turning disc, hook, and filament. Function: ATP is used to turn the discs in the basal body, which turns the whole flagella to provide movement. FIMBRAE Hair-like structures around the cell, made of protein. Function: Allows bacteria to attach to host. Strains of bacteria that are without fimbrae cannot attach and disease does not occur. SEX PILUS Special kind of fimbrae, but longer. Function: allows two cells to attach for conjugation and transfer of DNA from one cell to another.