Carl Richard Woese
Famous for defining the Archaea (a new domain or kingdom of life). Created the 3 Domain system based on RNA structure.
An invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages (these include fleas, ticks, and mosquitos).
Italian scientist who first attempted to disprove the idea of Abiogensis with his meat experiment.
English doctor who vaccinated people against small pox (with the help of the milk maids).
Proved Fermentation due to yeast; developed Pasteurization; and disproved Abiogensis.
The Father of Medical Microbiology. Proved Germ Theory through the development of pure culture techniques.
Koch's Postulates ( All 4)
1. The organism must be found in all cases of the disease.
2. The organism should be isolated in a pure culture.
3. When the pure culture of the organism is injected into a susceptible host, the identified disease should result.
4. The identical microbe should isolated from this host and isolated in a pure culture.
Was able to isolate Microbacterium Tuberculosis. Studied Cholera, Plague, and African Sleeping Sickness. Identified and discovered 20 major bacterial pathogens.
Compound Light Microscope
Uses visible Light, has a modified condenser which directs light towards the side of the specimen, is sometimes called Dark Field Microscope, and illuminated the specimen while leaving the surrounding dark. It typically used for bacteria which cannot be stained.
Phase Contrast Microscope
Uses visible light, takes advantage in refractive indexes (optical density) of cellular structures, to see objects light waves must be "in phase." Typically used for unstained specimens.
Differential Interference Microscope
Similar to phase contrast, contains additional light source and multiple prisms, 3-D appearance and more colorful. Also referred to as a "Nomarski Scope."
Modified microscope with an ultraviolet light source and protective eye filters uses dye that emit visible light when bombarded with shorter UV rays (useful in diagnosing infections using clinical specimens and fluorescent labeled antibodies.
Fluorescent-antibody techniques. Antibodies are attached to dyes, and if the antibody binds to its specific target, the target cell will show via fluorescence microscopy.
Laser illuminated, a laser scans over the specimen with the help of some scanning mirrors and the image is put on a computer for analysis, lasers are used because of their wavelength, salt can be seen in this microscope
Microscope that forms an image by focusing beams of electrons onto a specimen.
Scanning Electron Microscope
A microscope that is especially useful for the detailed study of the surface of a specimen; electron beams scan the surface of the sample, which is usually coated with a thin film of gold, allowing electrons on the surface to be deleted and translated into an image; result is a 3D topographic image. Can magnify from 1000x-100,000x
Transmission Electron Microscope
Magnifies about 1 million times; used to view the inside of the cell; a disadvantage is that the specimen must be: dead, frozen and cut into small slices in order to view it. Can magnify from 10,000x-1,000,000x
Membrane Bound Organelles: Present
DNA Structure: Multiple chromosomes. Histons Present
Chlorophyll: When present, in chloroplasts.
Ribosomes: In Cytoplasm and Rough ER, larger than Prokaryotes
Cell Walls: Only in Plants and Fungi.
Nucleus: No Nucleus.
Membrane Bound Organelles: None
DNA Structure: Single closed loop. No histons.
Chlorophyll: When present, dissolved in cytoplasm.
Ribosomes: In the Cytoplasm, Smaller than Eukaryotes.
Reproduction: Binary Fission
Cell Walls:Usually Chemically Complex
a localized region on the surface of an antigen that is chemically recognized by antibodies; also called antigenic determinant
Recognition of conserved and non-conserved regions.
Cells manufactured in the bone marrow that create antibodies for isolating and destroying invading bacteria and viruses.
Specialized white blood cells that fight disease either by activating B cells (helper____cells) or by attacking antigens directly (killer____cells)
Cell Mediated Immunity (T Cell)
Type of acquired immunity mediated by Helper T Cells and Cytotoxic T Cells
Toll-like Receptors (TLRs)
Receptors on phagocytes that often bind bacterial appendages, signaling as a trigger for the immune system.
Flagellum used by bacterial spirochetes, not a true appendage, offers crude motility
filamentous projection on a bacterial cell, used not for motility but for adhering to other bacterial cell (especially for mating) or to animal cells. Composed of "pilin" protein. Similar to "fuzz on a peach"
The 3 parts composing the Flagella structure
The filament, the hook, and the basal body (the motor)
Functions in attachments to substrates (help things bind to rocks in some cases), important virulence factor, composed of protein similar to pilin, and is tissue specfic
Composed of polysaccharides, function in retention of water and cell nutrients, can be easily removed in a stream/running water
Composed of repeating ogliosaccharide subunits or proteins, functions in the prevention of phagocytosis, cause adherence and promotion of biofilm formation
Stages of Phagocytosis
A community of cells surrounded by a capsule, composed of organic and inorganic constituents, form on surfaces in aquatic systems, resistant to biocides, release of organisms into bulk fluid
Stages of Biofilm formation
3. Microcolony Formation
4. Biofilm Formation
Biofilm Resistence to Antimicrobial Agents Steps
1. Slow penetration
2. Resistant Physiology
Impacts of Biofilms
Teeth, cooling water (Nuclear reactors), food processing, ship hulls, oil recovery, drinking water, paper manufacturing, and medical implants
Cell Wall Function
Binds cations (Mg++ and Ca++), rigidity and shape of the cell, protection from osmotic lysis, active site of certain antimicrobial agents (penicillin), antigens, and virulence factors
Composed of peptides and sugars, NAM-NAG-NAM-NAG-NAM alternating chains, connected via Beta 1-->4 linkages (Lysozymes can break this linkage)
Teichoic acids, a fortification wall, are bacterial polysaccharides of glycerol phosphate or ribitol phosphate linked via phosphodiester bonds. Play an important role in cell growth and antigenicity
an enzyme found in saliva and sweat and tears that destroys the cell walls of certain bacteria
Alternating L and D amino acids in sets of 4 (Linked only to the NAMs, not the NAGs), Pentaglycine (5 glycines) connects the linkages of NAG-NAM chains
Gram Positive Linkages present in peptidoglycan layer?
Yes. ~100% Cross-linking. In Gram + organisms, you can have ~40 layers of peptidoglycan, all with cross linking
Gram Negative Linkages present in peptidoglycan layer?
Yes. ~20% Cross-linking. In Gram - organisms, you can have ~1-3 layers, with only ~20% cross linking
Proteins that allow the passage of certain ions and small polar molecules through membranes.
In Gram-negative cells, the space between the cell membrane and the outer membrane containing peptidoglycan and periplasm.
Provides a protective barrier; help in adhesion, B Cell and Macrophage activator. The longer the sugar residue, the more antigenic and mucoid it becomes. It is composed of 3 sections: O Antigen region, Core polysaccharide region, and the Lipid A regions. Lipid A region is endotoxic (Causes fever, shock, spontaneous abortion, and death)
Essay Question for the first exam:
In detail, give the structure of the Gram Positive and Gram Negative cell walls. (At least a paragraph for each)
Exceptions to GP and GN structure:
1. Mycobacterium and Nocardia
4. Rickettsia and Chlamydia
Mycobacterium and Nocardia
Both genera cause respiratory disease, contain peptidoglycan along with high concentrations of lipids - mycolic acid, resist decolorization in the presence of acid. Therefore, these bacteria are termed Acid Fast Bacilli (AFB)
Mycobacterium Avium-intracellulare Complex
A type of infection particularly common in HIV patients
Are found in humans and most have no cell wall. Can cause pneumonia. Not affected by antibiotics which target the cell wall, no morphology
Obligate Intracellular parasite, cannot be grow outside of the cell (but IS NOT a virus), transmitted by arthropods, (Rocky Mountain Spotted Fever and Typhus)
Obligate Intracellular parasite, Chlamydia trachomatis is the most often seen, most common venerial disease in the world, the most common cause of preventable blindness in the world today
Composition: Phosopholip bilayer with embedded protein
Function: Osmotic barrier, transport, energy extraction, nutrient catalysis and processing, enzymatic biosynthesis and degradation
Extra chromosomal DNA elements. Can replicate independent of chromosome. Sometimes aid organisms by giving them a selective advantage (ex: antibacterial agent resistance, metal resistance, virulence factors).
Chemically similar to tubulin and actin. May help stabilize structure of bacterial cell and play a role in movement.
Small particles composed of rRNA and protein which direct the synthesis of proteins during translation. Composed of large and small subunits. Not bound to membrances. Smaller in prokaryotes than in eukaryotes.
How fast or slow a ribosome moves through a sucrose gradient. Dependent on mass and surface area.
Storage sites for nutrients or gas. Include: Lipids, Polysaccharides, Sulfur/Iron, and Polyphosphates.
Resilient structures which maintain the bacterial cell through periods of stress. Resistant to heat, radiation, dessication, and chemical treatment. Resistant outer coat contains high concentrations of dipicolinic acid and Ca++. Present in selected genera. [Bacillus (aerobic) and Clostridium (anaerobic)]
Vegetative cell --> Sporulating Cell --> Spore --> Germinating Spore --> Outgrowth --> Vegetative Cell
Bacillus anthracis (anthrax)
Bacillus cereus (GI infection)
Clostridium botulinum (botulism - muscles can't contract)
Clostridium tetani (tetnus - muscles stay contracted)
Clostridium perfringens (gas gangrene)
gas gangrene, works through the production of exospores (hard to find), produces lots of CO2 and H2, blows tissues apart.
Exotoxin blocks release of acetylcholine at neuromuscular junction preventing muscle contraction. Often transmitted through the food chain.
Disease affected Fore Tribe of New Guinea. Transmitted through cannibalism. Caused loss of muscle coordination, dementia, progressive insomnia, and death. Resistant to nucleases, proteases, heat, irradiation
Diseases similar to Kuru in animals:
Scrapie (in sheep/goats), Bovine Spongiform Encephalopathy (Mad Cow Disease), Chronic Wasting Disease (Deer/elk)
Diseases similar to Kuru in humans:
CJD, Fatal Familial Insomnia, GSS, and New Variant CJD (nvCJD)
Common features (Kuru)
Presence of amyloid rods, made of proteins, prions, associated with long incubation periods culminating in death
Infectious protein particles. Textbook definition: The protinaceous infectious agent of transmissable spongiform encephalopathies.
Protein sequencing revealed them to be proteins 27,000-30,000 daltons and composed of 145aa. Very similar to a protein in normal cells. Prions were termed: PrP^sc. Normal protein termed: PrP^c Normal proteins functions in binding Cu++
Transmission of Prions:
Horizontal transfer (i.e. cannibalism)
Effects of Prions:
Misfolding happens without the coding of nucleic acids. Misfolded proteins compel other proteins to misfold as well. Alpha helices form to Beta sheets. Rogue proteins aggregate to form amyloid fibils. Amyloid fibrils kill neurons.