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84 Cards in this Set

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What size are most microbes?
Smaller than 100 um.
What is the size range of a typical bacterium?
1-5 um.
What is the biggest bacterium and how big can it get?
Eupolpiscium, 600x80 um!!
How do viruses and viroids compare to bacteria? What is their size range?
They are truly molecular, and thus much smaller than bacteria. They range between 20-200 nm!!!
What are some larger microorganisms and how much might they weigh?
Fungi and algae can weigh many pounds.
What are the two major approaches to studying microbiology?
1) Studying microbiology for the sake of learning about the microbes themselves and their biology

2) Studying microbiology as an applied science centering on issues surrounding human affairs (medicinal microbiology, etc.)
Who discovered that prokaryotes are not a single evolutionary line and when did this shiznit go down?
Carl Woese in 1978
What are the three domains or "Superkingdoms" of organisms?
Bacteria, Archaea and Eukarya
Briefly distinguish bacteria from the other groups in the Three Domains
"Traditional" bacteria (formerly called Eubacteria)- They are prokaryotes
Briefly distinguish Archaea from the other groups in the Three Domains
Formerly called "Archaebacteria", they are prokaryotes. A unique and ancient evolutionary lineage, believed by some to be on the same early branch as eukaryotes.
Distinguish Eukarya from the other two groups of the Three Domains of organsisms
Eukaryotic orgnaisms that include traditional Kingdoms (animals, plants, fungi), as well as an incredily diverse number of transitional lineages (about 80 lineages in all!)
What are some "Organism-like" groups relevant to microbiology?
Viruses, Viroids and Prions
Whats a virus?
A simple molecular structure consisting of nucleic acid (DNA or RNA) and protein; obligate intracellular parasites; technically non-living.
Whats a viroid?
naked RNA only; obligate parasites.
Whats a prion?
Infectious protein, lack nucleic acid altogether, a biological paradigm. An example is the protein which causes bovine spongiform encephalopathy (or "Mad Cow Disease")
What are the two general features of microorganisms?
Simplicity and Diversity
Why are microorganisms "simple"?
They are largely unicellular, generally lack organization into specialized tissues, cells totipotent)
Why are microorganisms "diverse"?
The evolutionary, genetic and biochemical diversity of microorgnaisms is greater than all other organisms combined!
What were some early uses of microbes by humankind?
As food both directly (fleshy fungi) and indirectly (yeast to make bread, wine, etc.)

Medicinal herbs and plants used to control disease

Alcohol production dates back to 2400 B.C.

Salt was used to preserve foods from microbes but they didn't understand the microbial basis for it until much later
What are some of the issues and technological breakthroughs that microbiology developed around as a scientific discipline?
Technological breakthroughts: Discovery of microbes, culturing methods, biochemsitry, and molecular biology

Issues: spontaneous generation, the germ theory of diseases, discovery of immunology, development of chemotherapeutic agents.
Who desiged the first microscope based on a 2-lense design and when did they do it?
Johannes and Zacharias Jannsen in 1590
Who published the first drawings of cells and microfungi and when?
Robert Hooke in 1665
Who was Antoni van Leeuwenhoek and what did he do?
He was an amaeur microscopist who perfected methods of lens grinding; made the first accurate observations of bacteria (including coccoid, bacillarhy and spiral forms), protozoa, red blood cells, spimatozoa, yeasts, etc.
What did Martinus Beijerinck do in 1889?
He introduced the concept of viruses (sub-microscopic organisms)
Who was responsible for discovering the HIV is the cause of AIDS and when did they do it?
Robert Gallo and Luc Monatgnier in 1983
What is the theory of spontaneous generation?
A critical issue in the 17th and 18th centuries; debate concering association between appearance of microbial populations on organic substrate and simultaneous chemical changes (fermentation, putrefaction).
What did Lazarro Spallanzani do and when?
He did an experiment in 1765 in which he boiled broth and sealed the broth and the broth indefinetly remained sterile; he was trying to prove the spontaneous generation theory wrong, but critics claimed that it was because fresh oxygen was needed for it to work.
Who is Louis Pasteur and what/when is swan-necked experiment all about?
Louis Pasteur is known as the father of modern microbiology and he modified the Spallanzani experiment by using a swan-necked flask and proved that life could not be generated spontaenously by nonliving materials.
What were some of the other acheievements for which Louis Pasteur is so highly regarded other than his swan-necked flask experiment and when did they occur?
1854- His research saved the French wine industry- observations on good and sour fermentation; association of yeast with productive vats (bacteria with souring).

1857- Demonstrated microbial basis for souring of milk

1867- Developed pasterization (partial killing) process; commerical application by 1880 in Germany; pasterization does not kill heat-resistant endospores; John Tyndall later demonstrated effective killing of endospore-forming bateria by repreated boiling/incubation (Tydalliztion)
In Germny, Robert Koch and his colleagues did what in 1881?
They developed a rapid sterilization method using steam under pressure (160 degrees C) for one hour; development of standard laboratory autoclaves soon followed.
Germ Theory of Disease: What horrific incident happens in the 14th cenutry?
The bubonic plague kills 25 million people in Europe and the middle East. Numerous attempts to control the plague including prayer and flagellation are fruitless, until Venetian discovery of the quarantine.
Germ Theory of Disease: What occurs during the 16th century?
Girolama Fracostoro publishes De Contagione, a philosophical treatise on contagion via invisible 'germs', noted for insight into disease specificity and modes of transmission
Germ Theory of Disease: What occurs between 1840-1860?
OW Holmes and Ignaz Philipp Semmelweiss both made observations on the transmission of puerperal fever (child-bed fever), a major cause of maternal death during labor, and the effectiveness of sanitary practices in prevention. Semmelweiss was especially attacked by the medical community by insuiting that that physicians may have been responsible for thousands of deaths. Distraught and devastated by the scorn of his colleagues, Semmelweis had a nervous breakdown and died early.
What are Koch's Postulates?

*VERY IMPORTANT*
1) Organism must be present in diseased host and absent in the healthy ones

2) Causative organism must be isolated and grown in pure culture

3) Isolated organism must be able to cause disease in a susceptible host

4) Caussative pathogen must be reisolated and demonstrated to be identical with the original pure culture from postulate 2
What are some limitations/problems with Koch's postulates?
1) Many fastidious microorganisms and all viruses cannot be grown in pure culture

2) Some host may have immunity to a pathogen and are not susceptible to it

3) Many commensal microorganisms exist as part of a "healthy" host microflora but may later become opportunistic pathogens if host immunity is weakened or healthy flora becomes disturbed

4) Ethical considerations may limit testing of Koch's postulates, especially for experimentation with human and animal subjects, and especially with death-causing organisms
What were some of Koch's other contributions to microbiology outside of his postulates?
1) Development of solid media (agar and gelatin) for culturing microbes

2) Development of the Petri dish (by his student Richard Petri)
What are the Molecular Koch's Postulates?
They are an update to Koch's postulates proposed by Stanley Falkow in 1988 which employs molecular biology as a tool to associate microbial agents with disease; can even be used to prove that certain genes are assoicated with a particular disease
Development of Chemotherapy and Antibiotics: What did Joe Lister do and when?
Joe Lister introduced antiseptic techniques to the operating room; used carbolic acid (phenol) to soak bandages and mist working area
Development of Chemotherapy and Antibiotics: What did Paul Elrich do?
He was a student of Koch who performed studies on chemotherapeutic agents called "magic bullets"; developed salvarsan and neosalvarsan in 1912 for treatment of syphilis.
Development of Chemotherapy and Antibiotics: What did Sir Alexander Fleming do?
He discovered the anitbiotic properties of penecillin notatum.
Development of Chemotherapy and Antibiotics: What did Gerhard Domagk do?
He developed prontosil (first sulfa drug); the Trefouels later found the active ingredient of his prontosil to be slfanilamide (the first true "wonder drug" that was effective against many pathogens)
Development of Chemotherapy and Antibiotics: Who was Selman Waksman and what did he do?
He and his coworkers discovered streptomycin, a common soil actinomycete
Immunization and Immunology: Where is the origin of immunization?
It first occured in the Far East where controlled exposure to some diseases found to have a preventative effect.
Immunization and Immunology: What were cowpox pustules used for in 1798?
Used to innoculate against smallpox.
What term did Pasteur coin in the 1870's and what did he create?
He termed the coin "vaccination" for his vaccines that he created to ward against cholera, anthrax and rabies.
Molecular biology, Biochemistry and Biotechnology: What did Sergei Winogradsky do?
He described the first chemolithic bacteria
Molecular biology, Biochemistry and Biotechnology: What did Griffith do?
In 1928 he demonstated transformation using Steptococcus
Molecular biology, Biochemistry and Biotechnology: What did Avery, McLeod and McCarty do?
Demonstrated that DNA is the tranforming chemical.
Molecular biology, Biochemistry and Biotechnology: What did Beadle and Tatum do?
Demonstrated in 1950 the one-gene-one-enzyme theory in the fungus Neurospora crassa
Molecular biology, Biochemistry and Biotechnology: What did Watson and Crick do?
In 1953 they solved the structure of DNA
What occured between 1961-1980?
Recomibant genetics methods developed in E. coli and other microorganisms
What did Carl Woese and George Fox announce in 1977?
The discovery of Archaebacteria
What experimental release occured in the 1980's?
The experimental release of genetically altered bacteria into California potato fields; the patenting of microorganisms; first recominant drugs (insulin)
Molecular biology, Biochemistry and Biotechnology: What did Stanly Prsiner do?
He characterized prions in 1981
Molecular biology, Biochemistry and Biotechnology: What did Kerry Mullis do?
He discovered the polymerase chain reaction while driving in northern california in 1988
What occured between 1995-1999?
Sequencing of 100's of bacterial and several eukaryotic genomes
Basic Bacteriology: What are some of the primary methods for studying microboes?
1) Direct micropscopy examination -fundamental method

2) Cultivation of pure cultures

3) Biochemical tests- including enzymology, genetic characterization

4) Animal inoculation - used to study host specificity and etiology of disease

5) Immunological methods - based largely on antigen-antibody interactions, as well as study of mammalian immune system as it relates to specific microorganisms

6) Genertic characterization employing methodsof molecular biology, including DNA/DNA hybridization, PCR amplification, and DNA sequencing
What are the main components of light microscopy design?
Based upon compound design: light source, condenser, and two magnifying lenses (objective and ocular).
Basic micropscopy concepts: What is magnfication?
Product of ocular and objective magnification.
Basic micropscopy concepts: What is abberation and distortion?
Due to imperfections in lens, result in failure to focus in single plane.
Basic micropscopy concepts: What is chromatic aberration?
It results from differential refraction of different wavelengths, corrected by using multilayered lenses of different composition, as well as by using monochromatic light.
Basic micropscopy concepts: What is spherical aberration?
Due to differential refraction resulting from curvature of convex lens, corrected by use of plan apochromatic lenses.
Basic micropscopy concepts: What is pinhead and barrelhead distortion?
Results of uneven magnification at center or edge of lens
Basic micropscopy concepts: What is astigmatism?
Results from imperfections in lens causing uneven magnification
Basic micropscopy concepts: What is curvature of field?
Results in curved lines at edge of viewing filed, corrected with plan achromatic lenses
Basic micropscopy concepts: What is resolution?
Resolving power, based on ability to maintain detail. Closest discernible distance between two points.
Basic micropscopy concepts: What is resolution dependent upon?
Resolution (d) is dependent upon wavelength used (lambda) and numerical aperture (NA) of objective lens. Limit of resolution for light microscopy = 0.2 um.
What is the formula for resolution?
d= (wavelength of light in nm or Lambda) / (2*NA)
What is achieved by staining?
Contrast
What are simple stains?
Methylene blue is a postive simple stain and India ink is a negative simple stain. They stain everything they bind to the same color.
What is the difference between a positive and negative simple stain?
The electrical charges of the stains. Positive stains are positively charged and thus will bind to negatively charged molecules. Most general-use stains are positive stains b/c most of the things people are interested in seeing under light microscopy are negatively charged (cell membranes, etc.)
What is differential staining?
It is when a stain does not stain all kinds of cells the same caolor. A gram stain is an example of a differential stain.
What is the benefit of using a gram stain?
Gram stain uses mordant ot incresae stain affinity in certain bacteria but not in others, and thereby differentiates on basis of cell wall characteristics
What is an immunoflourescence stain?
Its a stain based upon antigen-antibody reaction, uses UB fluorescence (e.g. fluorescein isothiocyanate (green) and rhomadime (red)).
What is Phase Contrast microscopy (based on interference optics technology)?
A type of microscopy used to overcome the diffculties of seeing the intermal components of live, unstained cells. They work so that whe light passes through refractive material it slows down, goes out of phase, and thus causes intracellular features to appear lighter on a dark background.

The advantage of intereference methods is that they include the study of live material
What is electron microscopy?
Use of high-energy electron beam (60,000 volts), permitting shorter wavelengths (.005nm), and thus higher resolution (.2nm and less). Transmission EM is based on similar principles as compound light microscope - use of electron-dense stains and thin-sectioned specimen. Scanning EM is used to study surface details by detecting scatter of an electron beam aimed at the specimen. Preparation for SEM involves coating the specimen with an electron-scattering material (usually gold-palladium).
What is scanning probe and atomic force microscopy?
The most recent generation of microscopes can measure surface features by moving a sharp probe over an object's surface at magnifications of 100 millio or more (resolution of <.5 nm!). Scanning tunneling microscope has recently been used to view DNA directly. Atomic force microscopy can be used to study surface features of living cells at extremely high resolution.
What do growth media for microbes contain?
Source of reduced organic carbon, minerals and water. All bacteria require CHOPKNSCaFeMg (macronutrients) as well as Zn, Cu, Mn, Mo, Ni, B, Co And Na in some (micronutrients)
What is the difference between defined and undefined media?
Defined medium is a medium whose precise chemical composition is known
Preparation of media involves sterilization; what are some ways of sterilizing a medium?
Steam under pressure, gamma radiation, ultra-filtration (for heat labile material), chemical sterilization (ethylene oxide used to treat soil), or dry heat (150 degrees Celsius for 1-4 hours, used to sterilize implements).
What are the THREE requirements for aseptic technique?
1) Wiork area cleansed with anitseptic/wetting agent before and after;

2) Transfer instruments and container openings sterilized directly before and after transfer

3) Work is done quickly and efficiently
What are some methods of isolating pure cultures?
Use of streak-plate method (not quantitative), spread-plate (serial-dilution permits quantitation), pour plate (dilution into melted agar), and micromanipulation.
What are some of the goals of a successful maintenance/preservation of an organism
Goals: minimize risk of contamination, death, and mutation
What are some methods of maintenance/preservation?
Periodic subculturing, refrigeration with periodic subculturing, storage under mineral oil, under liquid nitrogen, or lyophilization (indefinite storage). Valuable 'type' strains and research strains maintained by non-profit culture collections, such as the American Type Culture Collection (ATCC).