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43 Cards in this Set
- Front
- Back
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What is the the killing or removal of all living organisms? When is this process important (3 areas)?
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Sterilization
Preparing media (after adding water), medical protocols, food systems |
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What method is used to kill vegetative cells and spores?
What two places is it performed? What are the specific settings? |
Autoclaving
performed in an autoclave or in fermentors 121° C, for 15 minutes with 15 lbs/in2. |
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Describe the process of tyndallization
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The solution is heated to 100° C for 30 min in the presence of flowing steam for 3 successive days.
After each heat cycle the material is incubated at 37° C until the next for the grow out of endospores, going from initial to final material |
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Pasteurization kills most BLANK and BLANK BLANK but not all bacteria.
It kills many things in milk; name 1 of the 4. |
pathogens; spoilage organisms
Mycobacterium tuberculosis (TB), Brucella abortus, Salmonella, and Lactococci in milk. |
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Is pasteurization sterile?
What are the two methods of pasteurization? |
NO
1. LTH, low temp hold: 62.8° C for 30 min. 2. HTST, high temp short term: 71.7° C for 15 seconds (used for food) |
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What is a bacterial killing method that uses a membrane with a certain pore size, 0.22 milli microns?
Where is this method used? What are some downsides? |
Filtration method
Used bacteria, certain chemicals, amino acids, certain drugs Can't filter viruses and is very slow |
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What is a bacterial killing method that uses filters to remove particles 0.3 milli microns or bigger?
Where is it used? WHEN is it used? |
HEPA filtration
Used in hoods; used when working with tissue culture |
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What is a bacterial killing method that uses gamma rays from cobalt 60?
What is it used on? |
Ionizing radiation
Used with foods and medical equipment |
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What is a bacterial killing method that uses UV rads at 260nm and causes T-T dimers?
What is a downside to this method? |
Nonionizing radiation
Bacteria can easily fix the bulge in DNA caused by UV light |
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What are chemicals that inhibit or destroy microbial growth?
What are three specific chemicals? Describe them. |
Antimicrobial Agents
Cidal agents, kill the organism. Static agents, reversibly inhibit growth of the organism. Lytic agents, cidal agents that destroy the microbe by cell lysis. |
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What are chemical compounds that destroy disease causing microbes and their products on inanimate objects?
What are less toxic and usually inhibit but do not always kill microbes? |
Disinfectants
Antiseptics |
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What is the measurement of the germicidal action of a chemical (disinfectant) and comparing it to phenol called?
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Phenol coefficient
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Common Disinfectants and Antiseptics
What is a 5 % solution effectively kills all vegetative bacteria and many spores through leakage of cell contents? Where is it used nowadays? |
Phenol
DNA isolation |
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Common Disinfectants and Antiseptics
What is a lipid solvent that kill cells by disrupting the lipids in the cell membrane? |
Alcohols
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Common Disinfectants and Antiseptics
What are cleaners that disrupt cell membranes commonly called? Name specific examples |
Surfactants
Ex: soaps, emulsifiers, detergents and cleansing agents |
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Common Disinfectants and Antiseptics
What are strong oxidizers react with proteins, enzymes? How many PPM need for disinfection, and surfaces? |
Halogens: chlorine, fluorine, bromine and iodine
0.5-1.0 ppm for disinfection, 200 ppm better for surfaces |
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Common Disinfectants and Antiseptics
What is iodophor? What two places is it used? |
detergent + iodine
used in fermentation; industrial cleaner |
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Common Disinfectants and Antiseptics
What is triclosan? What are three places it is used? |
An antibacterial
Used in Dawn dish soap, chemicals in the food industry, and toothpaste to destory gingivitis |
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Common Disinfectants and Antiseptics
What are substances that attach methyl or ethyl groups to proteins and DNA and results in death of the microbe? Name specific examples (3) |
Alkylating agents
Ex: formaldehyde, glutaraldehyde, ethylene oxide |
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Common Disinfectants and Antiseptics
What are substances that are toxic to microbes because they bind to sulfhydryl groups of proteins? Name specific examples (3) |
Heavy metals
Ex: Mercury, copper sulfate (on plants), and silver nitrate (eye drops in infants) |
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Who termed the phrase antibiotic? What did he discover?
What does an antibiotic show? |
Waksman; Discovered streptomycin
Zone of inhibition |
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Who brought about penicillin? What is the yield today?
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Fleming
from 1mg/L to 50g/L |
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How many antibiotics today? How many currently in production? How many are related structurally to penicillin?
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4,000
50 25 |
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How much and how long does it take to develop an antibiotic?
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$300 million and 10-12 years
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What makes a good antibiotic?
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Selective toxicity that inhibits and/or kills the microbe and not damage the host.
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How is an antibiotic developed?
What are two specific methods? |
Isolate bacteria and fungi from soil/water samples that inhibit test organisms like E. coli; extract the genes for production and resistance.
1. combinatorial chemistry: start with spore structure and add groups 2. rational drug design: start with crystal structure of target molecule and design and synthesize chemical that will impact it (ex: some antivirals) |
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What are the four areas where antimicrobials work?
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1. inhibition of cell wall synthesis
2. damage the cell membrane 3. inhibition of protein and nucleic acid synthesis 4. inhibition of cell metabolism |
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What are the structures common to penicillin G and V?
What destroys penicillin? What is resistant to this? |
B-lactam ring and thiazolidine ring; synthethic ex: ampicillian
B-lactamase from resistant bacteria Cephalosporins have a β lactam structure that is resistant to β lactamases. |
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How does penicillin inhibit bacterial cell wall biosynthesis?
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inhibition of the transpeptidation step in peptidoglycan synthesis.
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What are three antibiotics that damage the plasma membrane in bacteria?
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Polymyxin
nystatin amphotericin |
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Inhibitors of protein and nucleic acid synthesis
What impairs prokaryotic ribosome function, by interacting with the 30s ribosome, causing misreading of mRNA? Name 3 examples |
Aminoglycosides
Ex: streptomycin (Sm), kanamycin, neomycin |
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What does streptomycin specificially do?
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Sm impacts the 30s ribosome; inhibits initiation and codon recognition in protein synthesis
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Inhibitors of protein and nucleic acid synthesis
What interferes with the attachment of the aminoacyl tRNA to the ribosome and also interferes with codon recognition? |
Tetracycline (Tc)
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Inhibitors of protein and nucleic acid synthesis
What binds to the 23S rRNA on the 50S ribosomal subunit, inhibits peptide bond formation? |
Chloramphenicol
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Inhibitors of protein and nucleic acid synthesis
What binds to the 50S ribosomal subunit that blocks peptide bond formation? (This is a macrolide antibiotic, lactone ring attached to a sugar.) |
Erythromycin
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Inhibitors of protein and nucleic acid synthesis
What inhibit bacterial DNA dependent RNA polymerases? |
Rifamycins
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What are structural analogs? Name an example
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Items that compete with cellular metabolites in reactions
Ex: Sulfonamides are similar to PABA (precursor of folic acid) and therefore blocks vitamin synthesis. |
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Today, 2 to 3 antibiotics are need to kill bacterial infections. What are two examples of such bacteria?
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MRSA (Methicillin-resistant Staphylococcus aureus) and VISA (vanocomycin insensitive S. aureus)
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What are the two methods of antimicrobial testing?
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Tube dilution and disk diffusion method aka Kirby Bauer
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How does tube dilution work?
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Tube dilution involves broth tubes with different conc of antibiotic, checking for growth or no growth
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How does Kirby Bauer disk diffusion work?
Nowadays, it occurs in a... |
In KB, antibiotic placed on a plate. Bacteria grows right up to the disk (resistance), or a zone of inhibition (sensistivity)
broth |
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What two systems help maintain a continuous culture? Why is a continuous system economical?
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chemostat: growth controlled by the flow rate of the system, via fresh nutrients
The product is collected continuously turbidostat: device measures the turbidity of the growing cultures and adds fresh nutrients |
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What is it called when all populations are growing in the same phase or stage of growth on a growth curve?
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synchronous cultures
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