1.
3 types of RNA: 1. ribosomal (rRNA)
2. transfer (tRNA)
3. messenger (mRNA)
2.
acute period: - period of invasion
- Individual experiences classic signs and symptoms of disease
a. Sign: measurable, observed
b. Symptom: subjective, felt
3.
additive effects: - give the same effects as they would alone
4.
adverse effects of drugs: - allergic responses
- toxicity
- destruction of normal microbes
5.
aerotolerant: - don't care if oxygen is present, they will always use fermentation
- called obligate fermenters
6.
alcohols: a. Diluted solutions are more effective than pure alcohol, but evaporates rapidly.
- proteins more soluble and denature more easily when mixed with water
b. Antiseptic - coagulates enzymes, disrupts lipid membranes, little effect on endospores or naked viruses.
7.
aldehydes: - disinfectant/sterilizer
-toxic to humans
a. Formaldehyde-preservation of biological samples
b. Gluteraldehyde-sterilize medical instruments
*Problems? Carcinogenic.
- used for heat sensitive items!
8.
Alexander Fleming: - discovered the first antibiotic (penicillin) in 1928
- naturally occurring substance produced by fungus or other microbes
9.
alkylating agents: - add alkyl groups to nuclotides
- makes it so no Hydrogen bonding
10.
alteration in target molecule: - antibiotics recognize and bind to specific target molecules in a bacterium, interfering with its function
- BUT minor structural changes in target can prevent antibiotics form binding
11.
aminoglycosides: - PROTEIN SYNTHESIS
-Streptomycin, gentamicin
- Changes shape of ribosome causeing misreading of the mRNA (irreversible-cidal)
- Actively transported into cell by respiratory processes, therefore are not effective against anaerobes, enterococci, and obligate fermenters (streptococci)
12.
animal virus replication: 1. adsorption/attachment
2. penetration
3. uncoating
4. biosynthesis of genetic material
5. maturation
6. release
13.
animal virus replication - adsorption/attachment: attach to receptor molecule
14.
animal virus replication - biosynthesis of genetic material: 1) DNA virus- uses host cellular machinery. May make their own DNA polymerase
2) RNA virus (more on this when we discuss DNA). Requires production of a RNA dependent RNA Polymerase
a. If the genome is like mRNA it is termed positive stranded
b. If the genome is like template DNA it is termed negative stranded
3) Reverse transcription-requires reverse transcriptase which creates DNA from an RNA template.
15.
animal virus replication - maturation: -viral components self-assemble, usually near plasma membrane close to site of release
16.
animal virus replication - penetration: 1) Enveloped- can enter in one of two ways
a. Fusion
- lipid envelope fuses w/ plasma membrane --> nucleocapsid inside envelope released directly into cytoplasm
b. Endocytosis
- bind to receptors normally triggered for and facilitate mechanisms which cells bring in extracellular material, so cell takes virus in making an endocytic vesicle
2) Naked- endocytosis only
17.
animal virus replication - release: 1) Enveloped viruses bud (Fig. 13.15)
a. Must acquire envelope from living cell plasma membrane or ER/golgi. See constant production of virions.
b. Can modify envelope by inserting viral proteins (receptor/ligands) into the plasma membrane before budding.
2) Naked viruses generally burst and kill the infected cell and virions are released in a viral burst.
18.
animal virus replication - uncoating: nucleic acid separates from capsid
- fusion: envelope remains part of plasma membrane
- endocytosis: envelope fuses with endosomal membrane
19.
antagonistic effects: - interfere with each other
20.
antifungal drugs - cell division: - griseofulvin
- ring worm or jock itch
21.
antifungal drugs - cell wall synthesis: - echinocandins
22.
antifungal drugs - nucleic acid synthesis: - flucytosine
- yeast infection
23.
antifungal drugs - plasma membrane synthesis: - polyenes, azoles, allylamines
24.
antiparallel: two separate directions
25.
antiviral drugs: A. No naturally occurring antiviral drugs.
B. Use host's metabolic machinery to replicate, giving very few targets for antiviral therapy.
C. Mainly target three areas (what can we target on viruses?). Additionally, they are specific for a unique virus or genus of viruses and NOT used for all viruses.
26.
antiviral drugs - assembly and release of particles: - Protease inhibitors (HIV), neuraminidase inhibitors (influenza/ Tamiflu, Renlenza)
27.
antiviral drugs - nucleid acid synthesis: - herpesvirus family members and HIV
- Nucleoside analogs, Non-nucleoside polymerase inhibitors, non-nucleoside reverse transcriptase inhibitors
28.
antiviral drugs - viral uncoating: - Amantadine, Rimantadine
- only used against Influenza A.
29.
arthopods: A. Include insects, ticks, lice, and mites.
B. Some are simply vectors that transfer microorganism to humans and they themselves are not pathogenic. These are termed mechanical vectors
C. Some have a role in the life cycle of an infectious organism and are termed biological vectors.
30.
autoclave: - add pressure to wet heat (steam)
a. 15 minutes at 121oC, at 15 psi sterilizes most objects. Larger volumes of fluid will take more time to sterilize.
b. Need to allow steam into item being sterilized. Use sponges to block entry of airborne particulates for fluids, or just keep lids slightly unscrewed for bottles or beakers. Covering with aluminum foil works for materials inside beakers. Paper wrapping also works (similar to what Louis Pasteur did with his swan necked-flasks to keep bacteria out of his media)
31.
autoimmune response: - genetic component to autoimmune progression and higher risk for disease in women
32.
axial fibrils: - unique flagella
- covered by a sheath
****found only in spirochetes
- very motile
- can burrow through mucus membranes into tissues
33.
bacillus: rod
34.
bacitracin: - CELL WALL SYNTHESIS
- acts on the bactophrenol that transports peptidoglycan monomers out of the cell
35.
bacteria: -limited morphology
-divide by binary fission
-different shapes and organizations
36.
bacterial cell wall: 1) Peptidoglycan is composed of sugars and proteins (peptides)
a) Sugars are N-acetylmuramic acid (NAM) and N-acetylgucosamine (NAG).
b) A four amino acid peptide (tetrapeptide) is attached to every NAM sugar and is crosslinked by a peptide bridge or directly to another pentapeptide.
c) Some animo acids in the tetrapeptide are found ONLY in peptidoglycan:
(1) D-amino acids
(2) Diaminopimlemic acid
37.
bacterial cytoplasmic membrane: 1) Lipid bilayer composed of hydrophilic head and hydrophobic tails.
2) Selectively permeable - Water, O2 and CO2 can all enter and leave the cell by simple diffusion.
3) Water can cause the cell to swell and burst or in the presence of high osmotic concentrations to become dessicated or undergo plasmolysis.
4) Used to generate energy in prokaryotes
5) Has transport proteins embedded in membrane
a) Facilitated diffusion
b) Active transport
(1) Major Facilitator superfamily-Proton motive force
(2) ABC transporters-utilize ATP to bring molecules in
c) Group translocation-modify molecule chemically
6) Protein secretion (Fig. 3.30)-membrane bound protein structures that allow bacteria to excrete enzymes/toxins/effector molecules into the environment or cell.
38.
bacterial spores: - entirely resistant to disinfectants
39.
bacteriocidal: - kill organism
40.
bacteriostatic: - slow growth enough for immune system to come and wipe out
41.
base analogs: - synthetic bases that improperly base pair
- used in place of normal nucleotides b/c resemble them
- only work in viral infected cells
42.
beta lactam drugs: - CELL WALL SYNTHESIS
- active against growing/dividing microorganisms
- they bind and inactivate the transpeptidases used to create the peptidoglycan wall (transpeptidases are also called penicillin binding proteins)
- all have a beta lactam ring structure
43.
biosynthesis of DNA: 1) DNA viruses can use normal cellular enzymes to create genome or bring in special DNA polymerases that can allow a virus to replicated DNA when cell is not dividing.
2) Life cycles may complex.
44.
boiling water bath for 5 mins: destroys most microorganisms and viruses, but not effective means of sterilization
*requires minimus 30 mins to kill endospores
45.
broad spectrum: - affect on wide range
- acute life-threatening situations
- disrupts normal microbiota
46.
broad spectrum penicillin: -Semisynthetic penicillins- Ampicillin, amoxicillin
- works against gram negatives as well as gram positives
47.
carbapenems and monobactams: -CELL WALL SYNTHESIS
- aztreonam
- very resistant to beta-lactamases
- Carbapenems work against gram positive and negatives, monobactams work best against enterbacteria (gram negatives).
48.
cephalosporin: - CELL WALL SYNTHESIS
- have four generations of cephalosporins
- Cephalosporins of higher generation are normally broader spectrum against gram negatives (but lose their ability to target gram positives)
- Each generation of cephalosporin is more resistant to the action of beta-lactamases (however, beta-lactamases DO act on these drugs at low frequencies due to the presence of the beta-lactam ring)
49.
Chain and Florey: - followed through on Fleming's findings to isolate and produce penicillin
50.
chemical mutagens: A. Chemical mutagens- generally causes altered base pairing by changing the hydrogen bond formation of affected bases
51.
chloramphenicol: - PROTEIN SYNTHESIS
- inhibits peptide bond formation (static to cidal depending on concentration)
- Can cause aplastic anemia
- Has a low therapeutic index.
52.
cocci: spheres
53.
coccusbacillus: short rod/long sphere
54.
codon: - a three nucleotide sequence that determines the amino acid needed in protein
- Start Codon sets the reading frame for translation
55.
colonization: - microbe establishing itself and multiplying on body surface
56.
conjugation: 1) The F (fertility) plasmid contains information for the transfer of the plasmid and synthesis of a sex pilus. A cell containing an F plasmid is called F+. A cell without an F plasmid is F-
2) F+ Donor attaches to F- recipient via the sex pilus. The F plasmid is replicated and transferred to F- cell via rolling replication. The plasmid is reformed in recipient cell. F- recipient is then an F+cell
3) Integration of F plasmid into bacterial chromosome--> Hfr cell. Sometimes when the F factor excises itself, it does so incorrectly, taking a fragment of the bacterial chromosome with it. This is then termed an F'
57.
convalescent period: - period of recuperation and recovery
58.
D value: - the time it takes to reduce a bacterial population by 90% under specific conditions
59.
decreased uptake of drug: - changes in porin proteins can prevent certain drugs from entering the cell, so organism avoids effect of antibiotics
60.
degenerate/redundant: means that more than one codon can encode a specific amino acid
*However, each codon will always only specify ONE amino acid
61.
differences from DNA: 1. ribose sugar group
2. No thymine --> instead uracil
3. And RNA polymerase does NOT need a primer to start. Binds and recognizes a sequence in the DNA strand called a promoter
62.
direct repair: - uses Photolyase and light to repair thymine dimers
**this is only in bacteria!!
- methylguanine methyltransferase repairs improperly methylated/alkylated guanines
63.
DNA synthesis: 1. DNA is always synthesized in the 5' to 3' direction
2. 5' and 3' indicate which base of the sugar molecule being used
3. DNA nucleotides, Deoxyribose sugar/phosphate backbone.
a. C---G base pair
b. T--A base pair
4. Replication fork starts at the origin of replication HOWEVER!!!! DNA polymerase CANNOT START REPLICATION ON ITS OWN. DNA polymerase can only ADD DNA nucleotides to the 3' OH of a nucleotide.
5. DNA polymerase requires Primase to make an RNA sequence to allow DNA polymerase to start replication.
6. Helicase unwinds double strand. DNA gyrase allows the resulting tension in the double helix to be released.
a. Leading strand-continuous synthesis.
b. Lagging strand-discontinuous synthesis requiring many RNA primers. Okazaki fragments formed.
c. DNA ligase joins all fragments into on long continuous strand.
64.
drug-inactivating enzymes: - some bacteria produce enzymes that chemically modify a specific drug, interfering with its function
65.
dry heat: (item must be heat resistant)
- denatures, but proteins can be more stable in dry heat
1) Flaming inoculating loop - incinerates!
2) Bake items at 160-170OC for 2-3 hours. (not including heating up and cooling down time!)
66.
dyring/lyophilization: - decrease availability of water, limiting growth of most microbes b/c they NEED water to survive!
67.
E-test: - modification of K-B method
- multiple strips containing a gradient of concentrations of antimicrobial drug placed on surface of agar that has been inoculated with organisms
- produces teardrop shape clearing
- can help asses MIC
68.
emhambutol, isonazid, pyrazinamide: - acts specifically on the synthesis of the cell wall of the organism that cause tuberculosis, Mycobacterium tuberculosis.
69.
endospore: A. Forms when conditions for growth are poor. Allows bacteria to survive until conditions improve.
**SUSPENDED ANIMATION
1) Spore coat
2) Cortex is created from layers of peptidoglycan.
3) Core contains dipicolinic acid and calcium which helps protect the spore/DNA from environmental assaults.
B. Made primarily by gram positive bacteria.
C. Very resistant to drying, heat, and toxic chemicals
70.
environmental/animal: - you CANNOT eradicate these diseases ïƒ impossible!!!
1. i.e. tetanus, botulism, anthrax are out in the environment and can't be controlled
71.
ethylene oxide gas: -gas penetrates hard to reach places and fabrics
*Problems-toxic/explosive when mixed with CO2
- used for heat/moisture sensitive items!
72.
eukaryotic cell: A. Contain membrane bound organelles such as a nucleus, and golgi apparatus. Prokaryotes do NOT contain membrane bound organelles.
B. May have cilia or flagella, which differs in structure from prokaryotic flagella.
C. Have a cell wall (plants), but no peptidoglycan!
D. Eukaryotic ribosomes are 80S and composed of a 40S and a 60S subunit.
E. Mitochondria supply energy for cell. They divide by binary fission, contain 70S ribosomes, and have own circular DNA
73.
evolution: - new organisms evolve into pathogens.
i. i.e. turtles and salamanders are now dying off exponentially from diseases jumping from humans to salamanders that are not transferring the disease to turtles
74.
excision repair: - Dark repair
- uses enzymes to remove dimers
75.
experimental study: a. Placebo
b. Double-blind - physician as well as patient does not know who is on actual medication and who is not (placebo)
76.
extended spectrum penicillins: - more effective against gram negatives, but still can be rendered useless by beta-lactamases
- Ticarcillin and piperacillin
77.
facultative anaerobes: - use oxygen when present, but can grow by fermentation or anaerobic respiration when oxygen is absent
-Can produce both catalase and superoxide dismutase
*grow better when O2 present b/c aerobic respiration yields more ATP
78.
filtration: 1) Membrane filters -mainly for fluids
2) HEPA (high efficiency particulate air) filters
- removes particles larger than 0.3um
79.
fimbriae/pili: 1) bacterial appendages.
2) attachment, movement or some are specialized for conjugation
80.
flagella: 1) Allows bacteria motility:
chemotaxis-directed movement in response to a certain chemical in the environment.
a) monotrichious- Single polar flagella
b) peritrichious- flagella over entire surface
2) A bacterial flagellum is composed of:
a) Basal body - anchors structure to cell wall and cytoplasmic membrane; motor
b) Hook - flexible curved segment; connects filament to cell surface
c) Filament - extends into external environment; made up of 2 flagellin that twist into helical structure w/ hollow core
81.
fluoroquinolones: - NUCLEIC ACID SYNTHESIS
- ciprofloxacin inhibit topoisomerases (DNA gyrase) and acts to inhibit DNA synthesis (cidal)
82.
frameshift mutation: -addition or deletion of one or more basepairs to the genetic code
-a three nucleotide frameshift will result in the addition or deletion of one amino acid
**usually results in knockout mutation = shortened, non-functional protein
83.
fungi: A. Cell walls contain chitin, and plasma membrane contains ergosterol (not cholesterol)
B. Yeast- single celled, reproduce by budding or binary fission.
1) Molds- filamentous
a) Only molds form reproductive structures called spores
b) A spore germinates to form filaments that create a mycelium (Fig. 12.4).
2) Dimorphic fungi-grow as either molds or yeasts depending on environment.
84.
generalized transduction: 1) Bacteriophage injects phage DNA into a cell.
2) Phage DNA, capsid proteins, and phage structural proteins are made. The bacterial chromosome is destroyed.
3) Assembly of phage with phage DNA and a few that have mistakenly packaged bacterial chromosomal DNA instead of phage DNA.
4) Infection of new cell by newly synthesized phage- some containing bacterial chromosome fragments.
5) Cells infected by phage containing bacterial DNA can utilize information they receive. No new phage can be produced from these infections because viral genome is missing.
6) Undergoes homologous recombination with chromosome.
85.
genomic islands: - DNA that originated in another species
86.
glycocalyx: -predominantly composed of polysaccharides and is used for adherence and evasion of host defenses
1) Capsule-distinct and gelatinous
2) Slime layer-diffuse and irregular
87.
gram - cell wall: a) Periplasm-Space between plasma membrane and outer membrane. Contains peptidoglycan layer and enzymes.
(1) The peptidoglycan layer in a gram negative can be only a sheet or two thick.
(2) The peptide side-chains are directly linked (no interbridge).
(3) Lipoproteins connect outer membrane to peptidoglycan.
b) Outer membrane
(1) Lipid bilayer with embedded porin proteins. Porins allow molecules through the outer membrane into the periplasmic space.
(2) Lipopolysaccharide (LPS)- composed of Lipid A and highly organized series of polysaccharides -Lipid A, Core polysaccharides and O-side chain (Fig. 3.33, inset).
(3) LPS is also known as endotoxin, which has a large number of biological effects.
88.
gram + cell wall: a) Peptidoglycan with peptide interbridges.
b) Teichoic/lipoteichoic acid
(1) Helps to stabilize the gram positive cell wall and linked to NAM.
(2) Lipoteichoic acid helps to anchor the cell wall to the bacterial plasma membrane.
(3) Give the cell its negative charge.
89.
groups of bacteria: diplo=two
strepto=chains
staphlo=clusters
90.
growth curve - death phase: - total number viable cells decreases
- population decreases as cell die off at constant, exponential rate
(slower than log)
91.
growth curve - lag phase: - begin synthesizing enzymes required for growth
- length of phase depends on conditions in original culture and new
--> longer length if new medium has decreased nutrients b/c cell has to make new amino acids
92.
growth curve - log phase: - cells divide at constant, exponential rate
**when bacteria are most sensitive to antibiotics
- primary metabolites
-->Cells synthesize primary metabolites during log phase that allows them to grow more rapidly, such as amino acids, peptidoglycan and nucleic acids
-secondary metabolites
-->Cells start to synthesize secondary metabolites that allow them to become better competitors during late log but produce most secondary metabolites during stationary phase
93.
growth curve - prolonged decline: - some cells survive the death phase
*survival of the fittest as these cell are better equipped for survival
94.
growth curve - stationary phase: - nutrient levels too low to sustain growth --> scavenger mode
- # multiplying = # dying (plateau)
- use nutrients from dead cell to fuel living cells
95.
growth of organisms in a biofilm: 1. Free floating organisms attach to surface. Use glycocalyx, fimbriae, enhanced polymeric substances (EPS).
2. Highly structured with anaerobic, aerobic organisms growing in same structure.
3. More resistant to the effects of antibiotics and body defenses b/c are within EPs
ex) gunk in drain, plaque on teeth, buildup in toilet bowl
96.
gycosolyase: - repairs oxidized bases by cutting out oxidized bases
97.
halogen: -can be inactvated by organic compounds or impurities present on surface.
a. Chlorine- effective against almost all bacteria, viruses, fungi, and endospores. Common source of chlorine- sodium hypochlorite (bleach).* Only disinfectant.*
b. Iodine- used as a tincture (in alcohol) or as an iodophore. Can be used as a *disinfectant or antiseptic*
98.
helminth - cestodes: *TAPEWORM
a) Scolex-for attachment to intestine
- head has suckers and hooks for attachment
b) Proglottids-reproductive segments-**hermaphroditic
-up to 13-14 ft
99.
helminth - nematoda: *ROUNDWORMS
a) Dioecious
b) Can be found in gastrointestinal tract or in tissues/blood
--> host malnourished
c) Disease depends on infecting organisms.
-up to 30-40 cm
100.
helminth - trematodes: *FLUKES
a) Flat, leaf shaped, hermaphroditic and usually require an intermediate host such as a snail.
b) Infectious form is the cercaria that can penetrate skin
- can burrow through skin and get into respiratory system
101.
helminths: 1) Multicellular eukaryotic organisms. Parasitic helminths are not free living, lack digestive system, have reduced nervous system, with complex reproductive system (dioecious vs. hermaphroditic).
2) Life cycle may be extremely complex with a series of intermediate hosts for completion of a larval stage with definitive host for adult stage
102.
herd immunity: - protecting individuals who are not vaccinated (too young, too old, religious beliefs, cultural beliefs) by restricting the reservoir the pathogen
**NC nursing rules and guidelines require that every nurse must be properly vaccinated so that don't spread to patients b/c more likely to be vector or reservoir
103.
Hfr genetic transfer: - the integrated F plasmid is rarely completely transferred because replication includes the entire bacterial chromosome. Separation usually occurs before entire F plasmid is transferred. Therefore recipient cell receives DNA but usually remains F-.
104.
high pressure: -(130,000psi) pasteurizes food by denaturing proteins and permeability of bacteria
105.
how to get tapeworm disease: (1) Animals eating the eggs of tapeworms (or tapeworm proglottids filled with eggs) will develop into cysticerci in their gut. These then migrate out of the digestive tract and into the tissues.
(2) Eating undercooked meat (fish, swine or beef) containing cysticerci allows the scolex pass into the intestine and form a tape worm in your intestinal tract. You can ONLY get tapeworms from eating undercooked meat with cysticerci.
(3) However, eating the eggs of tapeworms (specificially pork tapeworms) allows the cysticerci to infect YOUR tissues, and these can embed in your muscles, eyes, or brain (called cysticercosis)
106.
human reservoir: - you can eradicate these diseases
1. i.e. smallpox is eradicated b/c everyone got vaccinated and the virus couldn't infect any humans, so it died
107.
hydrogen peroxide: - sterilant
- can be broken down by catalyase created by microbes (as well as human cells) can be used BEST as a disinfectant and not an antiseptic
- leaves no residue and can be used to sterilize food containers
108.
ID50: - number of microbes in a dose that will produce a demonstrable infection in 50% of inoculated test animals.
- the lower the ID 50 number is, the more infectious it is b/c it takes a lesser amount of the virus to cause the infection
- infectious dose
109.
If a drug is unstable at low pH, how is it administered?: IV or butt shot
110.
immunocompromised individuals: 1) Age-especially the very young (<1 year) and anyone over the age of 50.
2) Stress-especially college age students.
3) HIV
4) Organ transplant recipients
5) Pregnant women
6) Genetic factors
7) Excess in Drinking/Drugs
111.
incidence: - number of cases of a disease in a specific time
112.
increased elimination of drug: - when cell makes more efflux pumps, can expel antibiotic faster so not effective
113.
incubation period: - time between introduction of organism to onset of symptoms, no clue you have been infected
114.
infection: 1) Primary versus secondary infections.
- primary is initial infection
- secondary is additional infection as a result from primary infection
2) Primary vs secondary response
115.
innate or intrinsic resistance: - organism cannot be acted upon because of inherent resistance
**gram - more resistant to antibiotics b/c lipid bilayer of outer membrane prevents drugs from entering
116.
intercalating discs: - insert b/t pairs into DNA double helix and cause addition/deletion mutations
- increase frequency of frameshift mutations
117.
ionizing (gamma radiation): - sterilizes fairly rapidly
- protein, DNA damage, free radicals
- penetrates well
- can sterilize non-dividing organisms
**gram - most sensitive
- can sterilize heat sensitive items
i.e. medical equipment, surgical supplies
118.
issues with chemicals: may be toxic, lose activity in presence of organic material, be expensive, environmentally risky, have problems storing, or just not be compatible with what is being treated
119.
Kirby-Bauer Method: - used to determine susceptibility of given bacterial strain to a battery of antimicrobial drugs
- clear zone = bacteria is susceptible to drug!
120.
Koch's postulate: A. The microorganism must be present in every case of the disease.
B. The organism must be grown in pure culture
C. The same disease must be produced when a pure culture of the organism is introduced into susceptible hosts.
D. The organism must be recovered from the experimentally infected hosts.
121.
LD50: - number of microbes in a dose that will kill 50% of inoculated test animals
- lethal dose
122.
lincosamindes: - PROTEIN SYNTHESIS
- clindamycin inhibit protein synthesis (static)
- Good against wide variety of gram pos. and gram neg. organisms, however Clostridium difficile is resistant, emerging threat
123.
lytic viral replication: 1) Attachment-must bind to a receptor on a cell to attach. If the receptor is not present, the virus will not be able to attach, affords tropism to the virus
2) Genome entry - tail contracts and phage DNA injected into bacterial cell
3) Synthesis - phage genome transribed and phage protein synthesized --> phage DNA replicated, virion components made, host DNA degraded
4) Assembly - phage components assembled into mature virions
5) Release - bacterial cell lyses and new infectious virions released
124.
macrolides: - PROTEIN SYNTHESIS
- Erythromycin, clarithromycin, azithromycin-prevents protein synthesis (static)
- Works best against gram positives
125.
major differences - introns: prokaryotes - no introns
eukaryotes - introns which are removed by splicing
126.
major differences - processing: prokaryotes - mRNA not processed
eukaryotes - cap is added to 5' end of mRNA and poly A tail added to 3' end
127.
major differences - translation: prokaryotes - translation of mRNA begins as being transcribed
eukaryotes - mRNA transcript transported out of nucleus to be translated in the cytoplasm
128.
major differences between prokaryotic and eukaryotic transcription/translation: 1. Processing
2. Introns
3. Translation
4. Humans only make monocistronic mRNA whereas bacteria are capable of making polycistronic mRNA
129.
mechanisms of pathogenesis: A. Production of toxins that are ingested.
B. Colonization of mucous membranes of host, followed by toxin production.
C. Invasion of host tissues.
D. Invasion of host tissues followed by toxin production.
130.
microaerophile: - can tolerate only low levels of oxygen
- can only produce small amounts of catalase and superoxide dismutase
131.
microwaves: - just heating water in cells
132.
minimum bactericidal concentration (MBC): - lowest concentration of an antimicrobial that kills 99.9% of a given organism
- this assay is performed in combination with the MIC assay
---> the actual organisms used in the MIC test, which survived the MIC of the drug, are exposed to increasing concentrations of the same drug
---> the lowest concentration of antibiotic that then kills all bacteria will be the MBC
133.
minimum inhibitory concentration (MIC): - lowest concentration of a specific antimicrobial drug needed to prevent visible growth of a given organism in vitro, without killing
- determined using serial dilutions of one antimicrobial drug
134.
mismatch repair: - repair uses methylation to indicate parental strand of DNA and removal of incorrectly paired bases
- bacteria methylate adenines
135.
missense: -changes codon and wrong amino acid is inserted into peptide chain
**change in the phenotype as well as genotype
136.
morbidity: - incidence of illness in regard to specific disease
137.
mortality: - death rate in regard to specific disease/population
138.
mycobacterium species: - thick waxy cell calls can't be penetrated by gram stains
139.
naked viruses: - resistant to alcohol and many disinfectants
140.
narrow spectrum: - limited range
- pathogen must be identified
- less disruption to microbiota
141.
natural penicillins: - Penicillin G& V-(narrow spectrum)- work only against gram positive organisms
142.
nitrous oxide: - changes base structure
- converts C to U
143.
non-ionizing (UV): - due to lower energy waves, need longer time to sterilize
- does not penetrate
- damages DNA
- works best on actively multiplying organisms
144.
nonsense: - causes the formation of a stop codon. **change in the phenotype as well as genotype
145.
nosocomial infections: - infections and disease not present before hospitalization.
i. Responsible for about 20,000 deaths in the U.S. per year.
1. Approximately 10% of American hospital patients (about 2 million every year) acquire a clinically significant nosocomial infection
146.
nucleoid: 1) Nuclear area containing usually containing a single, circular closed chromosome of DNA. 2) No structural component involved.
3) Chromosome is supercoiled and must be replicated prior to or during cell division.
147.
nutritional requirements: a. Carbon source
A. carbon from inorganic source (CO2): autotrophs
B. Carbon from organic sources (other organisms): heterotrophs
b. Energy source is either light (phototrophs) or chemicals (chemotrophs)
c. Organisms that get electrons from same source as their carbon (organotrophs), from inorganic molecules such as H2S and Fe2+ (lithotrophs)
148.
obligate aerobes: require oxygen, can produce both catalase and superoxide dismutase
149.
obligate anaerobes: -cannot TOLERATE the presence of oxygen-grow only in the absence of oxygen -cannot produce either catalase or superoxide dismutase
150.
operons: 1. Operons consist of promoter, operator region, and set of regulated genes.
2. Control of transcription of the operon is regulated by DNA binding proteins known as repressors or activators.
a. Repressors stop transcription.
(a) An inducer blocks the ability of a repressor to bind to DNA.
(b) A co-repressor will block transcription by enhancing binding of DNA by a repressor.
b. Activators induce transcription. When an inducer binds to an activator, it causes the activator to bind to DNA and induces transcription.
151.
osmolarity and water availability: a. Plasmolysis- loss of H2O due to osmosis of water out of an organism. This causes the plasma membrane to shrink from the cell wall.
b. Halophiles/halotolerant-capable of growing in high salt concentration. Can control the loss of water from the cytoplasm in highly osmotic circumstances.
152.
ozone: -unstable form of oxygen used as an alternative to chlorine for disinfecting drinking/waste water
- unstable and breaks down very rapidly.
153.
pasteurization: - reduces number of organisms, does not sterilize.
a. HTST (high temperature short time) 72OC for 15 sec
b. UHT (ultra high temperature)- 140-150OC for 2-3 sec.
154.
pathogen factors: A. Virulence
B. Dose
C. Incubation period
155.
penicillinase: - resistant penicillins
- methicillin, dicloxicillin
156.
penicillins + beta-lactamase inhibitor: - Augmentin (amoxicillin and clavulanic acid)
157.
peracetic acid: - more potent than H2O2
- can be used in the presence of organic compounds, leaves no residue and can be used on a wide range of materials
**Only disinfectant
158.
persistence of infection - acute: - illness is short term b/c pathogen is eliminated by the host defenses
- person is usually immune to reinfection
159.
persistence of infection - chronic: - illness persists over a long time period
1) i.e. mononucleosis: can have symptoms for 3 weeks, but then still shed the virus for up to 18 months after
160.
persistence of infection - latent: - illness may recur if immunity weakens
1) i.e. chicken pox: can reactivate later in life as a result of stress, age, etc.
2) another example is herpes viruruses
161.
pH: a. Neutrophiles- grow at neutral pH of about 7 (body pH- normal range is 6.5-7.5 pH).
b. Acidophiles- grow optimally at low pH < 6.5 pH.
c. Alkaliphiles- grow best in high pH of > 8.5
162.
pH - acetic acid: - vinegar
- plasmolysis
163.
phenolics: - act on cytoplasmic membrane and denatures proteins. Do not reliably inactivate all viruses. However, they can leave an active antimicrobials residue. Non-toxic.
a. Hexachlorophene -works best against S. aureus however, may be neurotoxic.
b. Triclosan-where isn't it?
**one of earliest disinfectants!
164.
plasmid: 1) Small, circular extrachromosomal DNA.
2) Self-replicating. Therefore can replicate independently from the chromosome and cell division.
3) Vitally important in obtaining genetic codes for virulence factors from other bacteria.
*this increases antibiotic resistance
165.
pleomorphic: many shaped
not specific shape
166.
point mutation/base substiution: single change in base pair
**most common type of mutation
167.
polycistronic messages: - Some viruses create polycistronic messages that get translated into a polyprotein.
1) Requires the polyprotein to be cleaved into functional proteins.
2) Requires a virally encoded protease to be processed.
168.
polymyxin B: - PLASMA MEMBRANE
- topical only
169.
prevalence: - total number of cases (old and new) that has occurred in a given population
170.
primary vs opportunistic pathogen: A. Primary pathogen - When we have them, Will always cause infection/disease
1) i.e. the flu
B. Opportunistic pathogen - Commensal organism that is allowed into protected sites.
1) i.e. Staph epidermidis (catheters can transmit this if not properly used and sterilized; increased resistance in hospitals now)
171.
prodromal period: - initial feelings of malaise
172.
prokaryotic binary fission: 1. One cell divides into two daughter cells. Must replicate its chromosome during division.
2. Generation or doubling time- the time it takes for a cell to reproduce under optimal conditions.
3. Results in exponential growth. To determine the number of microbes afte N0 x 2n
173.
prokaryotic ribosome: A. 70S -Composed of a 30S and 50S subunit. Each subunit is composed of specific proteins that are complexed with RNA to form a structure.
B. Found in cytoplasm of bacterium and can be directly associated with mRNA that is being transcribed
174.
promoter: - genes can be located on either strand of DNA, so it is the promoter that indicates where the gene is
- the promoter is always upstream from the gene and the gene is in the 5' to 3' direction from the promoter
175.
protozoan cysts and oocysts: - more innately resistant to disinfectants, BUT killed by boiling for 5 minutes
176.
protozoans: A. Very few are pathogenic
B. Unicellular, eukaryotic, found in water and soil.
1) Feed on bacteria and particulate nutrients, digestion occurs in vacuole and waste eliminated via plasma membrane or anal pore.
2) May reproduce sexually or asexually
a) Trophozoite- vegetative or feeding form
b) Cyst- resting form of protozoan, allows it to survive during adverse conditions, similar to bacterial endospores.
3) May have cilia, flagella or pseudopodia
177.
pseudomonas species: - can grow in tap water with little nutrition
- can grow in disinfectants b/c resistant
178.
quaternary ammonium: - aka Quats
a. Like commons soaps and detergents reduce surface tension of liquids.
b. Quats are cationic (positively charged) and attracted to the negative charge of cell surface and reacts with membrane
i Destroys vegetative bacteria and enveloped viruses
ii Not effective on endospores, mycobacteria and naked viruses
iii Aids in removal of dirt and organic matter and facilitates mechanical removal of organisms
179.
quorum sensing/ antigenic: A. Specific genes are activated only when critical mass is achieved
B. Antigenic/phase variation uses different transcripts which allows organisms to evade host responses.
*can "sense" and "talk" to each other
180.
refrigeration: - inhibits growth of many pathogens and spoilage microorganisms by slowing or stopping critical enzyme reactions but NOT psychophilic or psychotrophic organisms!
181.
reproductive cycle of temperate (lysogenic) bacteriophages: 1) Attachment to bacterium
2) Insertion of genome
- linear chromosome
3) Depending on environmental circumstances virus can do one of two pathways.
a. Lytic infection - replication of phage DNa and synthesis and release
b. Lysogenic infection - occurs during lysogeny, but allows specific bacteriophages to be produced
i) Insertion of viral DNA into bacterial chromosome at specific sites generating a prophage.
ii) Bacterial replication
iii) Excision of phage DNA
iv) Progression into lytic cycle
v) Lysogenic conversion
182.
reservoirs: A. Human
1) Carriers
2) Symptomatic/asymptomatic infections
B. Animal reservoirs
1) Animal reservoirs for disease that can infect humans and animals (rabies)
2) Zoonosis-accidental infection of human by animal pathogens (Lyme disease)
C. Environmental
183.
resistance factors: 1) Plasmid is a circular extrachromosomal piece of DNA that replicates independently of chromosome. Has own origin of replication.
2) R plasmid confers resistance to various antimicrobials agents such as antibiotics, or heavy metals. May or may not be conjugative.
184.
rifamycins: - NUCLEIC ACID SYNTHESIS
- binds RNA polymerase and inhibits mRNA synthesis (cidal)
- resistance develops rapidly
185.
RNA Viruses usually replicate in the cytoplasm: 1) Positive stranded RNA virus-its genome is like mRNA.
a. Genome can be directly read by cell's ribosomes to create enzymes, viral components.
b. Can encode a viral RNA dependent RNA polymerase. (Remember, similar to mRNA).
2) Negative stranded RNA-genome is in the negative orientation.
a. Needs to bring in a viral RNA dependent RNA polymerase (working enzyme) so that it can make viral mRNA to create viral proteins.
b. No enzyme in living organisms to create mRNA from mRNA...
c. Targets for anti-viral drugs?
186.
salting/sugaring: - draws water out of cells and dehydrates them
- freeze-drying - first frozen, then dried in vacuum
187.
Salvarson: first antimicrobial agent
188.
selection pressure: - result of use of antibiotics to select organism that have mutated or acquired resistance factors that allow them to survive
189.
selective toxicity: - causing greater harm to microbes than to human host
190.
semi-conservative replication: 1. DNA replication occurs ONLY when the cell is dividing.
2. Double stranded DNA is ALWAYS created by copying a new strand using an existing/template strand of DNA.
3. The template is commonly termed the parental strand
4. The newly synthesized strand is commonly termed the daughter strand.
191.
shape of bacteriophage and animal viruses: 1) Helical/Filamentous
2) Isometric/icosohedral (20 faces)
3) Pleomorphic
4) Complex (bacteriophages)
192.
silent: no effect on the phenotype because of degeneracy of genetic code
**normally 3rd base in codon
193.
similarities to DNA: 1. RNA polymerase can only make mRNA in the 5' to 3' direction.
2. Must use DNA as a template to create the proper sequence.
194.
SOS repair: - Repair enzymes induced when TOO many thymine dimers have been created
- new polymerase is activated that repairs DNA by replicating DNA with many mutations due to the presence of many too many dimers
**NEVER DONE IN HUMANS B/C SO SLOPPY!
*guess at bases and hopes to get them right!
195.
specialized transduction: -only regions of chromosome near phage attachment sites can be moved
1) Lysogenic conversion occurs.
2) However, when phage genome is excised some of the bacterial chromosomal DNA is excised instead of the entire bacteriophage genome.
3) Transfer of bacterial chromosome to new bacteria occurs.
4) Phages may still be able to generate progeny phage depending on how much DNA from bacterial chromosome was excised.
196.
spiral/spirillum: spiral rod
197.
spirochete: helical rod, corkscrew, VERY MOTILE
198.
spontaneous mutations: - chances of mutation low
- can accumulate over time with selection pressure
ex. one base pair change can make streptomycin resistant
199.
start codon: - AUG (ATG in DNA), is always the first codon in a protein following a ribosomal binding site sequence
- If AUG is internal in protein, will also code for methionine
200.
stop codon: - three stop codons indicate the end of the coding sequence which terminates translation
- these do NOT code for an amino acid.
201.
streptogramins: - PROTEIN SYNTHESIS
- synergistic combination of two drugs that can together be bactericidal
- they act on TWO sites of the 50S subunit
- individually they are static
202.
sulfonamides: - FOLIC ACID, NUCLEOTIDE SYNTHESIS
- sulfa drugs
- chemotherapeutic
203.
surfactants: - detergents which act to primarily disrupt cell membrane.
a. Anionic detergents -common soaps and detergents reduce surface tension of liquids- Aids in removal of dirt and organic matter and facilitates mechanical removal of organisms
b. Little antimicrobial effect
204.
synergistic effects: - enhance each other
205.
technical: ability to create pathogens
206.
temperature requirements: a. Psychrophiles-cold loving bacteria.
b. Psychrotrophs- grow best between 20 oC and 30 oC .
--> important cause of spoilage in refrigerated foods
c. Mesophiles- Primarily body temp. (Human body temperature is 37 oC).
*common bacteria*
d. Thermophiles and hyperthermophiles-heat loving prokaryotes, mostly archaea
**cold and freezing temps don't necessarily/usually kill bacteria, but rather inhibit them!
207.
tetracyclines/glycylcycline: - PROTEIN SYNTHESIS
- Block attachment of tRNAs reversibly (static)
*Problems: cause discoloration in teeth of children
208.
therapeutic index: - lowest dose toxic to patient divided by the dose typically used to therapy
*high therapeutic index = less toxic!
209.
transcription: 1. The negative strand is the template strand and is used to create a copy of the positive strand (which contains the gene).
2. RNA polymerase binds promoter with help from sigma factor (this recognizes promoter regions). Other transcription factors aid in ribosomal binding (yes, bacteria DO have transcription factors).
3. RNA polymerase melts open a stretch of DNA and reads the negative strand of DNA (it has to read in the 3' to 5' direction in order to synthesize mRNA in the 5' to 3' direction-just like with DNA).
4. Transcription ends when a terminator is encountered. The terminator occurs when the RNA forms a hairpin structure, which allows the RNA polymerase to dissociate from the DNA.
5. mRNA released
210.
transfer of genetic information: - horizontal
- conjugation --> R plasmids that carry several different resistance genes
211.
transformation (experimentally induced): - Electroporation can induce a bacterium that is not competent to take up naked DNA - Plasmids or double stranded DNA (dsDNA) can be taken up
- Cells can be made chemically competent where large pores are induced in the plasma membrane
212.
transformation (naturally occurring): - naturally competent cells receive naked DNA, via a receptor on their cell surface.
1) Single stranded pieces get incorporated into bacterial chromosome by homologous recombination.
2) Mismatch repair or cell division determines if the newly acquired genetic material is expressed.
213.
translation: **process of decoding info carried on mRNA to synthesize a specific protein
a. All three RNAs come together: ribosome (rRNA)/mRNA/ tRNA
b. Initiating tRNA with fMet amino acid moves into P site on ribosome. This is the only amino acid that enters at the P site.
c. Next tRNA fills A site.
d. Peptide bond formation occurs and the 1st tRNA released via the E site.
e. Ribosome shifts and amino acids are added by reading codons until a stop codon is encountered.
1) Termination of protein synthesis at stop codon.
2) Translation machinery falls off.
f. Translation in Bacteria - can occur simultaneously with transcription.
214.
transmission: A. Contact
1) Direct
a. easiest way to get infected with cold
2) Indirect-fomites or inanimate objects which can transfer disease.
3) Droplet transmission
B. Food/water
C. Air
D. Vectors
215.
transposable elements: - jumping genes --> have ability to insert ANYWHERE regardless of promoter, etc
1) Barbara McClintock
2) Insertion sequence (IS) (most basic form of moveable element) -Inverted repeats and the enzyme transposase. Transposase is the enzyme that allows transposon to "jump". Can inactivate the gene they jump into
3) Composite transposon-contains two IS that flank a resistance factor.
**don't need homologous recombination
216.
transposons: - randomly insert into DNA causing inactivation of the gene
217.
trimethroprim: - FOLIC ACID, NUCLEOTIDE SYNTHESIS
- bacteriostatic
218.
UV radiation: - causes thymine dimers --> covalent bonds b/t adjacent T molecules
- thymine dimers do not allow DNA polymerase to correctly read DNA coding sequence due to kinks in structure
- UV irradiation does not penetrate well
219.
vancomycin: - CELL WALL SYNTHESIS
- binds to the tetrapeptide sidchain, not to penicillin binding proteins
220.
vibrio: curved rod
221.
viral genome: 1) Nucleic acid containing all the genes necessary for virus to reproduce.
2) Contain only a single species of nucleic acid, either DNA or RNA, never both.
222.
viral mutation and mutation rates - integration: - integration of viral/cellular genetic material can change cell morphology, insertional inactivation or change the way the cell divides
223.
viral mutation and mutation rates - viral oncogenes: - gene whose activity is involved in turning a normal cell into a cancer cell.
a. Termed viral transformation (this is different from bacterial transformation).
b. Example: HeLa cells, transformed cells from Henrietta Lacks.
224.
virion: one single infectious viral particle
1) Nucleocapsids
2) Genetic material
3) Viral envelope
4) Viral spikes
225.
viroids: -simpler than virus
-single, short piece RNA
-obligate intracellular parasites
PLANT DISEASES!
ONLY RNA!!
226.
virulence: - degree of pathogenicity of an organism
- makes more harmful and more of a primary pathogen instead of opportunistic
227.
virulence factor: - traits of microorganism that specifically allow it to cause disease
228.
viruses: A.Are not alive but can replicate in a living cell.
B.Are obligate intracellular parasites.
(not active unless INSIDE HOST!)
C.Viruses are usually not named in the binomial manner like living organisms and usually just referred to by species names.
(named based on shape and appearance, genome, and where they infect)
RNA or DNA!!
229.
viruses: A. Bacteriophage (phage) infect prokaryotes
B. Animal viruses infect eukaryotes
1) Naked
2) Enveloped
230.
Viruses associated with cancer in humans are usually ? viruses?: DNA
231.
What is made when a cell wants to make a specific protein?: mRNA
232.
X-rays /gamma rays: - ionizing
-causes double stranded breaks in DNA backbone due to higher energy wave
- Ionizing radiation penetrates most material well
**harder to repair than thymine kink
