Microbiology Exam I

an infecting microorganism able to cause disease

• biotechnology- manipulate microorganisms to make products to in an industrial setting
• recombinant DNA technology- potential in terms of medical, industrial, and agricultural uses
• bioremediation- introduction of microbes into the environment to restore stability or to clean up toxic pollutants

• biogenesis- living organisms arise only from others of their same kind (cells could only come from other cells, the cell was the simplest component of an organism)
• abiogenesis (spontaneous generation)- belief that living organisms arose from vital forces present in nonliving and decomposing matter

1673- reports the 1st observation of bacteria and protozoans

• (biogenesis)
• 1670's- 1st to disprove spontaneous generation
• Left out jars of rotting meat, some were sealed and others were not
• Meat in the jars exposed to the air developed maggots. Those covered did not
• Scientists concluded that killing the microorganisms that caused disease could prevent the disease from occurring (proved biogenesis law correct)

• (biogenesis)
• 1748- did hay infusion experiment
• boiled hay & water & put in jar; no microbes
• unboiled hay & water in jar; got microbes
• infusion lacked endospores

• (abiogenesis)
• experiment on mutton gravy
• microbes still grew in the gravy flasks
• done before the realization that heat resistant microbes are not killed by mere boiling.
• microbes in the gravy produced endospores

• (biogenesis)
• Repeated Needham’s experiment, but he boiled the meat broth longer than Needham. The sealed flask did not become cloudy with microorganisms, but the open flask did.
• 1. Needham had either failed to heat his vials sufficiently to kill all microbes
• 2. Microorganisms exist in the air and contaminate all experiments
• 3. Spontaneous generation of microorganisms does not occur; all living arise from other living

• (biogenesis)
• 1857- refined the process of fermentatio
• propesed the germ theory of disease which states that microorganisms cause infectious disease
• 1861- last to disprove the doctrine of spontaneous generation
•      experimented with boiling beef broth ( airbone organisms contaminated open flasks)
•     used swan necked jars
• 1864- discovered the process of pasteurization which is one of the best known sterilization techniques
• 1855- introduced the vaccines against rabies and anthrax

• 1867- introduced aseptic techniques
• surgeons to use phenol to wash and disinfect their hands before surgery
• disinfection of wounds with phenol
• supported the germ theory of disease

• studied Anthrax bacterium and its transmission in animals
• 1876- verified germ theory of disease with Koch's postulates
• 1881- introduced techniques for pure cultures introducing solid culture medium
• 1882- discovered M. tuberculosis
• 1905- won Nobel Prize in Medicine/ Physiology

• Postulate #1: the same microorganism must be present in every case of the disease
• Postulate #2: the organism should be isolated from the tissues of the infected animal and grown in a pure culture
• Postulate #3: the organism from the pure culture is inoculated into a healthy animal and the same disease should be produced
• Postulate #4: the pathogen must be isolated from the experimental animal and shown to be the original organism

• 1928- discovered penicillin (growing bacteria in media)
• Penicllin notatum, at one time, killed Staphylococcus aureus, leading cause of infection

• 1. Redi (first 1670's)
• 2. Jablot
• 3. Spallanzani
• 4. Pasteur (last, 1861)

• 60's "time to close the book on infectious disease" (Luther Terry, 1964)
• 90's "infectious diseases a rising peril- up 58% since 1980" (David Satcher, 1998)

infectious diseases most common death in much of fumanity

• no nucleus is visable (single circular chromosome) (nucleoid)
• lack membrane bound organelles
• have cell walls that generally consist of peptidoglycan
• divide by binary fission
• appendages
• motility
• cell envolope
• cell wall
• gram staining
• no mitochondria
• plasmids
• ribosomes
• bacterial endospores
• fimbriae and pili

• nucleus
• membrane bound organelles
• no cell wall
• have mitochondria
• the chromatin is associated with histone proteins

• Flagella (propellers)- motility
• 1. Monotrichous- 1 flagella
• 2. Amphitrichous- flagella on both sides
• 3. Lophotrichous- tuft of flagella
• 4. Peritrichous- around the cell

• Polar flagellum rotates:
• counterclockwise---> swim forward
• clockwise--> stops and tumbles
• Petrichous flagella:
• all flagella sweep toward one end of the cell and rotate as a single group ---> forward
• flagella rotate in the opposite direction cause the cell to lose cordination--> tumbles

• internal flagella
• between the cell wall and cell membrane and spirals around the cell
• aka axial filaments or endoflagella
• present in bacteria known as spirochetes:
• 1. Treponema pallidum
• 2. Borrelia burgdorferi
• curl, free to contract and allow the cell to twist and flex
• Spirochetes

• the outer wrapping of bacteria
• 3 layers:
• 1. Glycocalyx
• 2. Cell Wall
• 3. Cell Membrane

• outermost coating of bacterial cells
• subcategories:
• 1. Slime layer
• 2. Capsule

• part of glycocalyx sublayer of bacterial cells
• loose and disorganized layer of macromolecules
• for attachment
• white plaque formed by surface slimes

• part of glycocalyx sublayer of bacterial cells
• formed by:
• 1. Stephtococcus pneumonia
• 2. Haemophillus influenzae
• 3. Bacillus anthrax
• 4. Streptococcus mutans

• Negative stains are used to reveal the presence of negatively charged bacterial capsules.
• Encapsulated cells appear to have a
• halo around them.

• second layer of the cell envelope of a bacterial cell
• consits mainly of a macromolecule called peptidoglycan , peptides, lipoproteins and lipopolysaccharides
• give bacteria their characteristic shape and structural support
• Most bacteria to live, or capable of living in hypotonic environments. Their cell walls protect them from bursting from the increased osmotic pressure.
• Hypertonic solutions inhibit or kill bacteria

• Two types of cell walls:
• 1. gram (+) cell walls
• 2. gram (-) cell walls

• stain purple
• lack outer membrane
• larger peptidoglycan layers (20-80nm)
• high PG content--> allows to retain dye
• stain purple
• the many layers of peptidoglycan are resistant to alcohol, therefore, it will stain purple

• stain red
• have an outer membrane (lipopolysaccharides)
• thin layer of peptidoglycan
• the alcohol dissolves lipids in the outer membrane and removes dye
• because the gram(-) bacteria are colorless, the red dye adheres to the cell
• may prevent the movement of penicillin to the underlying peptidoglycan, impeditive to the treatment of disease

• 1. Mycobacterium and Nacardia
• contain peptidoglycan and stain gram (+)
• composed of mycolic acid (fatty acid chain)
• not found on gram stain
• found by Ziehl-Neelsen stain
• 2. Acid fast stains
• 3. Archae
• 4. Mycoplasmas

• have a cell wall but may have lost it due to :
• mutations in the wall forming genes
• treatment with lysozyme or penicillin that disrupts the cell wall
• L forms are associated with some chronic infections

• innemost layer of the cell envelope
• phospholipid bilayer
• functions:
• site where energy reactions take place (cellular or anaerobic respiration, donate and accept e-)
• selectively permeable

• small pieces of DNA (1-4 genes)
• plasmids acquired from other bacteria allow cells to grow fimbriae (hair-like structures sprouting off some bacterial cells for attachment) and capsules
• may allow a cell to become resistant to anitbiotics

• extension of the cell membrane that folds into the cytoplasm and increases surface area

• elongate, hollow appendage used in transfers of DNA to other cells and in cell adhesion

• "inclusion bodies" extra food
• store bodies
• Metachromatic granules: contain inorganic phosphate reserves (nucleic acids)
• Polysaccharide granules: glycogen and starch
• Lipid and sulfer inclusions
• inorganic compounds and are not bound by membranes

• resting cells or dormant bodies
• by gram (+) genera
• Bacillus and Clostridium
• these cause anthrax, tetanus, and gangrene
• are dehydrated and have a very thick cell wall rich in dipicolinic acid, which makes them extremely hard to destroy
• can resist for extremely long periods of:
• 1. Drying
• 2. Freezing
• 3. Radiation
• 4. Chemicals
• 5. Alcohols

• triggered by depletion of nutrients
• triggered by water, favorable conditions, and the presence of a germination agent (an amino acid or an inorganic salt)

• uses heat to drive the primary stain
• malachite green (spore)

• 1. Bacillus anthrax (Anthrax)
• 2. Clostridium tetani (Tetanus)
• 3. Clostridium botulinum (Botulism)

• 1. Gram
• 2. Shape
• 3. Arrangement

• 1. Coccus
• 2. Bacilli
• 3. Spirilla

spheres, oval shaped, kidney or bean-shaped, or slightly pointed

• 1. Diplococci
• 2. Tetrads
• 3. Steptococci (chains)
• 4. Staphylococci (clusters)

rod shaped or cylindrical

• 1. Bacilli
• 2. Coccobacillus
• 3. Diplobacilli
• 4. Palisades
• 5. Streptobacilli

• curved rods
• polar flagella
• Cholerae
• gram (-)

• type of spiral bacteria; helical and flexible; move by means of axial filaments
• (resemble flagella but are contained within a flexible external sheath)
• syphilis and Lyme

• DNA or RNA (nucleic acid)
• genetic material is surrounded by a protein coat (caspid)
• not a complete cell

• made out of hyphae (filaments)
• exist in two forms:
• 1. Yeast: single celled organisms
• 2. Molds: when they produce long, tubular, branching filaments known as hyphae
• ability to switch from the hyphal cells typical of molds to yeast cells typical of the parasitic phase  (thermal dimorphism)

unicellular eukaryotic cells that contain specialized structures for feeding movement and reproduction

• Eukaryotic, multicellular organims (animals)
• 0.3mm to tapeworms over 20 ft long
• 3 main groups:
• 1. Nematodes (roundworms)
• 2. Cestodes (tapeworms)
• 3. Trematodes (flukes)

• Nematodes (roundworms)
• cylindrical with cuticles

• Cestodes (tapeworms)
• have long ribbon like bodies composed of proglottids and a scolex

• Trematodes (flukes)
• flatworms with leaf like bodies bearing suckers