Exam 1 Flashcards
Symbionts that harm or live at the expense of their host
parasitic organisms
Microbes frequently found on or within the bodies of healthy persons:
commensal organsims
Commensal organisms may also be referred to as:
normal microbiota
What makes up the vast majority of normal flora?
bacteria
Colonization of ___ occurs rapidly after birth
bacteria
Locations in which large amounts of bacteria reside:
- skin (esp. moist areas)
- respiratory tract (nose and oropharynx)
- digestive tract (mouth & large intestine)
- urinary tract (anterior parts of urethra)
- genital system (vagina)
locations in which small amounts of bacteria reside:
remainder of respiratory and digestive tracts
Locations in the body in which NO bacteria are present (sterile):
blood, CSF, synovial fluid, and deep tissue
Normal flora found all over:
resident organisms
Resides in an area for a limited time:
transient organisms
Growth or multiplication of parasite on or within host:
infection
Disease resulting from infection:
infectious disease
Any parasitic organisms that cause infectious disease:
Parasite
Causes disease by DIRECT interaction with host:
primary (frank) pathogen
Causes disease only under certain circumstances (such as after antibiotic tx)
opportunistic pathogen
ability of a parasite to cause disease:
pathogenicity
any component of a pathogenic micro that is required fro or that potentiates its ability to cause disease:
virulence factor
Pathogenicity and virulence depend on:
the host
What are the steps in an infectious disease:
- encounter
- entry
- spread
- multiplication
- damage
- outcome
What are three types of encounters with a pathogen?
- exogenous
- endogenous
- congenital
When a pathogen is externally derives (such as a sneeze)
exogenous encounter
When a pathogen is internally derived (such as a change in immunity/health; already inside)
endogenous enconter
When a pathogen is picked up during birth (such as HIV from mother to fetus)
congenital encounter
What are two forms of entry of a pathogen?
- ingress
- penetration
Entry of a pathogen via inhalation or ingestion:
ingress
Entry of microbes through epithelial directly (via attachment and internalization):
penetration
Insect bites, cuts and wounds, organ transplants, and blood transfusions are all examples of what type of pathogenic entry into the host?
penetration
What are three components to the spread of a pathogen:
- lateral propagation vs. dissemination
- anatomical factors
- active participation by microbes
Spread of a pathogen to neighboring tissues:
lateral propagation
Spread of a pathogen to distant sites:
dissemination
What are the two components to the multiplication of a pathogen when causing an infectious disease?
- environmental factors
- subversion of host defenses
Damage inflicted by an infectious disease can be cause by:
- direct damage
- immune response
What are the outcomes of an infectious disease?
- microbe wins
- host wins
- they learn to coexist
If an infection comes from our normal flora, the source of infection is considered:
endogenous
Overgrowth of particular bacteria in gingival crevices:
periodontitis
When defenses are lowered and micro aspirations of pneumococci occur:
pneumococcal pneumonia
Catheter-associated infections are typically a result of:
staphylococci
What do the following have in common:
- periodontitis
- pneumococcal pneumonia
- catheter-associated infections:
All have endogenous source of infection- normal flora actin up
What are the roles of normal flora?
- immune stimulation
- keeping out pathogens
- assist in nutrition
- source of carcinogens vs. detoxification of carcinogens
Normal oral flora include:
bacteria, fungi, protozoa, and viruses
How many different species are estimated to be present in the oral cavity?
over 500
What are the different oral habitats?
- buccal mucosa
- dorsum of tongue
- tooth surfaces
- crevicular epithelium
- dental appliances
Issues for microbial cells include:
- nutritional fluxes
- maintaining occupancy
- resistance to damage
List all of the factors modulating oral microbial growth:
- anatomical features that create areas that are difficult to clean
- saliva
- gingival crevicular fluid
- microbial factors
- local pH
- redox potential
- antimicrobial therapy
- diet
- iatrogenic factors
____ are an absolute require for all living organisms
membranes
describe the plasma membrane:
- highly organized
- asymmetric
- flexible
- dynamic
The lipid components of the plasma membrane form a:
lipid bilayer
The polar end of the lipids in the lipid bilayer are ____, while the non polar ends of the lipids in the lipid bilayer are ____.
polar –> hydrophilic
nonpolar–> hydrophobic
Proteins that are loosely associated with the plasma membrane that can easily be removed:
peripheral proteins
Proteins that are embedded within the membrane that are not easily removed:
integral proteins
bacteria version of cholesterol that provides rigidity:
bacteriohopanetetrol
Functions of the plasma membrane include:
- separation of cell from environment
- selectively permeable barrier
- location of crucial metabolic processes
- detection & response to chemicals via receptor molecules
granules of organic and inorganic materials that are stockpiled by the cell for future use:
inclusion bodies
some inclusion bodies are enclosed by a:
single layered membrane
The single layered membrane that encloses some inclusion bodies: (2)
- vary in composition
- some made of proteins, others of lipids
Complex structures consisting of protein and RNA:
ribosomes
Sites of protein synthesis:
ribosomes
Compare the size of eukaryotic and prokaryotic ribosomes:
prokaryotic ribosomes are smaller
Size of prokaryotic ribosome:
Size of eukaryotic ribosome:
70s; 80s
Irregularly shaped region in bacteria in which a chromosome resides:
nucleoid
Is the nucleoid membrane bound?
no
In cells, what do the nucleoid projections indicate?
cells are actively growing; DNA being actively transcribed
Describe a prokaryotic chromosome:
- closed, circular, double-stranded DNA molecule that is looped and coiled extensively
Proteins that help to fold prokaryotic chromosomes:
nucleoid proteins
Describe some unusual circumstances of nuceloids:
- more than one chromosome
- LINEAR double stranded DNA
- membrane-delimited nucleoids
Small, closed, circular DNA molecules that exist and replicate independently of the chromosome:
plasmids
Plasmids are NOT required for:
growth and reproduction
Plasmids may carry genes that confer ____ such as ____.
selective advantage; drug resistance
Rigid structure that lies outside the plasma membrane:
prokaryotic cell wall
List the functions of the prokaryotic cell wall:
- provides characteristic shape to cell
- protects the cell from osmotic lysis
- may contribute to pathogenicity
- may protect cell from toxic substances
Bacteria are divided into two major groups based on:
response to staining (rx due to cell wall structure)
Gram positive cells stain:
purple
Gram negative cells stain:
pink
In a gram positive cell, the cell wall is composed of:
primarily of peptidoglycan
Cells that contain large amounts of techoic acids:
gram positive cells
polymers of glycerol or ribitol joined by phosphate groups
techoic acid
Space between plasma membrane and cell wall:
periplasmic space
Gram positive bacteria secrete:
exoenzymes
In gram positive bacteria, the exoenzymes serve as the ____ do for gram negative bacteria
periplasmic enzymes
Cell wall that consists of a thin layer of peptidoglycan surrounded by an outer membrane:
gram negative bacteria
The outer membrane in gram negative bacteria is composed of:
lipids, lipoproteins, LPSs
NO techoic acid present:
gram negative bacteria
What type of bacteria are more permeable?
Gram-negative
space between plasma membrane and outer membrane in bacteria:
periplasmic space
In gram negative bacteria, what is contained within the periplasm?
periplasmic enzymes
What are roles of periplasmic enzymes?
- nutrient acquisition
- electron transport
- peptidoglycan synthesis
- modification of toxic compounds
Describe the structure of peptidoglycan:
- polysaccharide formed from two peptidoglycan subunits
- two alternating sugars form backbone
What two alternating sugars form the backbone in peptidoglycan?
N-acteylglucosamine (NAG); N-acetylmuramic acid (NAM)
Within the peptidoglycan structure, _____ have a direct link between peptide chains, while ____ contain a peptide inter bridge (Gly) between side chains
Gram-negative bacteria; Gram positive bacteria
This image is showing a ____ cell wall
gram-positive
what is under the thick peptidoglycan layer in a gram-positive cell wall?
single membrane bilayer
This image is showing a ___ cell wall
gram negative
In a gram-negative cells, there is a ____ structure with each being a bilayer.
double membrane structure
Connect outer membrane to peptidoglycan in gram-negative bacteria:
Braun’s lipoproteins
Sites of direct contact between plasma membrane and outer membrane in gram negative bacteria:
adhesion sites
Substances may move DIRECTLY into gram negative bacteria via:
adhesion sites
What are the three components of a lipopolysaccharide (LPS)?
- lipid A
- core polysaccharide
- o-side chain (O-antigen)
Component of the LPS that inserts into the outer membrane structure for stabilization & can also act as an endotoxin:
Lipid A
The lipid A component of the lPS inserts into:
the outer membrane
Component of the LPS that contributes to the negative charge on the cell surface:
Core polysaccharide
What does the negative charge contributed by the core polysaccharide portion of LPS function to do?
avoids/masks host defenses
What two components does the core polysaccharide portion of the LPS contain?
keto-deoxyoctoenic acid and heptose
Portion of the LPS that provides protection from host defenses:
O-side chain
What component of the LPS is visible to our immune system:
O-antigen
Which membrane in more permeable in a gram-negative cell?
outer membrane
Why is the outer membrane of a gram-negative cell more permeable than the plasma membrane?
due to presence of porin proteins and transporter proteins
Form channels in the outer membrane through which small molecules can pass:
porin proteins
Layer outside of the cell wall that is well-organized, not easily removed from the cell, and takes the shape of the underlying cell
capsule
Layer outside of the cell wall that is similar to the capsules except diffuse, unorganized, and easily removed
slime layer
Capsules and slime layers are both referred to as:
glycocalyx
network of polysaccharides extending from the cell surface:
glycocalyx
What are the functions of the glycocalyx? (4)
- protection from viral infection or predation by bacteria
- protection from chemicals in environment
- motility of gliding bacteria
- protection against osmotic stress
Short, thin, hairlike, proteinaceous appendages (1000/cell)
fimbriae
What is the function of fimbriae?
mediate attachment to cell surfaces
Similar to fimbriae except longer, thicker, and less numerous (1-10/cell)
sex pili
What are sex pili required for?
mating; transfer of genetic material
What is the function of flagella?
motility
List the arrangements of flagella:
- monotrichous
- polar flagellum
- amphiptrichous
- lophotrichous
- peritrichous
One flagellum:
monotrichous
Flagellum at end of cell:
polar flagellum
One flagellum at each end of cell:
amphitrichous
cluster of flagella at one or both ends of cell:
lophotrichous
flagellum spread over entire surface of cell
peritrichous
Describe the flagellum ultrastructure:
- filament
- basal body
- hook
Portion of flagellum that projects out of cell surface
filament
Portion of flagellum that is anchored within the plasma membrane or within both plasma & outer membrane
basal body
portion of the flagellum that is a protein components that gives a bend to the structure:
hook
dormant form created when a bacterium encounters environmentally challenging conditions that make it difficult for the cell to keep growing
endospore
The bacterial endospore is resistant to numerous harsh environmental conditions such as:
- heat
- radiation
- chemicals
- desiccation
Overview of eukaryotic cells include:
- membrane-delimited nuclei
- membrane-bound organelles that perform specific functions
- more structurally complex than prokaryotic cell
- generally larger than prokaryotic cell
Elements required in large amounts:
macroelements
List the macroelements required for microbial physiology that are cell components of carbs, lipids, proteins, and nucleic acids:
- carbon
- oxygen
- nitrogen
- hydrogen
- sulfur
- phosphorus
The macroelements required for microbial physiology make up components of:
- carbohydrates
- lipids
- proteins
- nucleic acids
List the macroelements required for microbial physiology that exist as cations and play many roles including cofactors of enzymes:
- potassium
- calcium
- magnesium
- iron
List the trace elements required for microbial physiology:
- manganese
- zinc
- cobalt
- molybdenum
- nickel
- copper
Trace elements are mainly needed as:
cofactors of enzymes
components required for ALL organism survival:
- source of energy
- source of reducing equivalents (electron donors)
- source of carbon
Organisms that utilize light as a source of energy:
phototrophs
Organisms that oxidize organic or inorganic compounds as a source of energy:
chemotrophs
Organisms need electron donors for:
- ETC (energy producton)
- Redox reactions (energy production)
- Biosynthesis (in autotrophs from CO2)
utilize INORGANIC molecules as a source of reducing agent:
lithotrophs
utilize ORGANIC molecules as a source of reducing agent:
organotrophs
Utilize CO2 as the main/only source of carbon:
autotrophs
Utilize reduced, preformed organic molecules (such as glucose) for source of carbon:
heterotrophs
due to the the source of carbon utilized, most pathogenic bacteria are considered:
heterotrophs
- light energy source
- Inorganic electron donor
- CO2 carbon source
photolithotrophic autotrophy
- light energy source
- organic electron donor
- organic carbon source
photoorganotrophic heterotrophy
- chemical energy source
- inorganic electron donor
- CO2 carbon source
chemolithotrophic autotrophy
- chemical energy source
- organic electron donor
- organic carbon source
chemoorganotrophic heterotrophy (all pathogens)
Other nutrient sources required for bacteria include:
- nitrogen source
- phosphate source
- sulfur source
- growth factors
List where bacteria may get their source of nitrogen from:
amino acids, ammonia or nitrate (NO3-)
A few may obtain nitrogen from N2 (atmospheric nitrogen)
List where bacteria may get their source of phosphate from:
inorganic phosphate (PO4^3-)
List where bacteria may get their source of sulfur from:
sulfate (SO4^2-), or reduced sulfur (cysteine)
List where bacteria may get their growth factors from:
amino acids, purines and pyrimidines, & vitamins (small organic molecules)
- perform aerobic respiration only
- final electron acceptor is oxygen (reduced to H20)
strict aerobes
- perform anaerobic respiration
- final electron acceptor is an inorganic molecule (such as nitrate of Fe3+)
strict anaerobe
- perform fermentation
- final electron acceptor is an organic molecule (such as pyruvate reduced to lactate or acetyl-coA reduced to ethanol)
strict anaerobe
- can perform respiration & fermentation
- most medically relevant bacteria
facultative anaerobe
Final electron acceptor of strict aerobes:
oxygen (reduced to H2O)
Final electron acceptor is an inorganic molecule
strict anaerobe that performs anaerobic respiration
Final electron acceptor is an organic molecule:
strict anaerobe perfomring fermentation
Give an example of a facultative anaerobe and explain:
E. coli- can survive on a Petri dish (aerobic), and can survive in the intestines (anaerobic)
The respiratory chain of E. coli occurs in ______ ; for us it occurs in the _____.
membrane of cell; mitochondria
Unique to the oral cavity and requires a certain amount of CO2 in addition to oxygen
Capnophillic
List the gram positive bacteria in the oral cavity:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
List the shapes of the following gram-positive oral bacteria:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
- cocci
- cocci
- rods
- rods
List the oxygen requirements for the following gram-positive oral bacteria:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
- facultative anaerobes
- strict anaerobes
- strict/facultative anaerobes
- facultative anaerobes
List the gram-negative bacteria found in the oral cavity:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
List the shapes of the following gram-negative oral bacteria:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
- cocci
2-6. rods - spirals
List the oxygen requirements of the following gram-negative oral bacteria:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
- strict anaerobes
- capnophillic
- capnophillic
4-7. strict anaerobes
- move from higher concentration to lower concentration
- NO ENERGY requirements
facilitated diffusion
What is facilitated diffusion uptake driven by?
intracellular use of the compound
Compare the rate of facilitated diffusion vs. passive diffusion:
facilitated diffusion is much faster
What happens to the rate of facilitated diffusion as the concentration gets smaller:
as concentration gets smaller, the rate gets smaller, however the rate is more magnified at smaller concentrations
Carrier proteins embedded in the plasma membrane:
permeases
An active transport mechanism in which transported substances are chemically altered during the process:
group translocation
Group translocation may also be called:
phosphorylation-linked transport or phosphotransferase system
An example of group translocation would be:
glucose –> glucose-6-phosphate
system that moves a phosphate group and covalently links it to a transporter molecule; very common within bacterial cells:
group translocation
Where does the phosphate bond come from in group translocation and what does this serve as:
phosphoenolpyruvate (PEP); energy source
Some ____ & ____ are transported via group translocation
sugars & cariogenic bacteria
Energy is used to drive accumulation of a substance, which remains unchanged by the transport process:
active transport
Form of active transport that uses proton motive force (gradient of protons) by coupling to an energetically unfavorable transport event (concentration of a substance against a gradient)
Ion-driven transport systems
Give an example of a molecule that would use ion-driven transport systems:
amino acids
Coupling energetically favorable + unfavorable processes:
symport
Form of active transport that use membrane proteins that form a channel and drive substances through the channel using the energy from ATP hydrolysis:
binding protein-dependent transport systems
Give an example of a molecule that would use binding protein-dependent transport systems:
sugars & aminoacids
In all active transport mechanisms the transport processes use carriers that:
can become saturated
ferric iron is very ____, so ____ is difficult.
insoluble; uptake
Because ferric iron is insoluble and difficult to uptake, microorganisms use ____ to aid in the uptake.
siderophores
Describe the process of ferric iron uptake in microorganisms:
siderophore complexes with ferric iron and the entire complex is then transported into the cell
E. coli can grown on greater than 30 different ___ compounds, using each to obtain ____ , ____ & ____.
Organic compounds; carbon, H+/electrons, and energy
Bacteria that can use several hundred compounds to obtain carbon, reducing agents, and energy:
pseudomonas
_______ organisms have complex needs and can only grow in association with the human body or in complex culture medium (example: blood agar)
nutritionally fastidious
Given and example of a nutritionally fastidious bacteria:
staphylococci and streptococci
Have to replicate within living cells, but unlike viruses, they can carry out metabolic processes
obligate intracellular parasites
Give an example of a bacteria that is an obligate intracellular parasite:
chlamydia
Microbial growth in the real world is considered:
suboptimal
Different organisms have ___ growth rates
variable
What is a factor that protects bacteria?
stress responses
bacteria can still cause damage to the host when not growing through
- toxin production
- immunogenic processes
Mechanisms of adaption of bacteria function to:
- maximize efficiency in using energy and resources
- respond to changes
What are the results of regulation by microorganisms:
- pathways can be switched on or off
- pathways can be turned up or down
How is control among microorganisms established:
- enzyme activity
- number of enzyme molecules
All enzymes have ____ for catalysis, but some enzymes have ____ for regulation.
active sites; allosteric sites
____ sites bind regulatory molecules
allosteric sites
Describe the binding of a regulatory molecule to an allosteric site:
- noncovalent
- reversible
- affect activity of enzyme
Positive effectors ____ activity; while negative effectors ____ activity of an enzyme.
increase; decrease
In allosteric regulation: the higher concentration of regulatory molecules=
more activity
In allosteric regulation, effectors act to:
- change affinity of enzyme for substrate
- change vmax (rate of reaction)
Results in premature termination of transcription of mRNA:
attentuation
In attenuation, the ___ becomes stalled in the ___ of the mRNA (upstream of the coding region on the enzyme)
ribosome; attenuator region
During attenuation, even though transcription is not complete, what can occur and why?
translation can begin because transcription and translation occur simultaneously in bacteria
During attenuation, ____ are important for mRNA folding.
secondary structures (hairpin)
An example of a secondary structure used for mRNA folding during attenuation:
hairpin
In attenuation, what happens when leucine is present?
When leucine is present, leucine-rich region allows ribosome to read and translate A and B regions, causing formation of a C-D hairpin strucutre
In attenuation when leucine is present and a C-D hairpin is formed, this causes:
the RNA polymerase to dissociate from the DNA, terminating transcription
In attenuation when leucine is present and a C-D hairpin is formed, this causes termination of transcription, ultimately:
preventing the cell from making the enzyme to create more leucine
In attenuation, what happens when leucine is absent?
When leucine is absent, a high demand for leucine tRNA causes the ribosome to stall, allowing for formation of B-C hairpin structure
In attenuation when leucine is absent and a B-C hairpin has formed this allows for:
transcription to occur
In attenuation when leucine is absent and a B-C hairpin has formed, this allows for transcription to occur and ultimately:
RNA polymerase will transcribe the rest of the operon and produce more leucine
In attenuation if abundant leucine is present, the ribosome:
reads through leucine-rich region
In attenuation if no leucine is present, the ribosome:
stalls with high demand for leucine tRNA
Controlling the NUMBER of enzymes can be accomplished through:
attenuation
Controlling the initiation of transcription can be accomplished through:
catabolic & anabolic pathways
Controlling transcription initiation in a catabolic pathway is accomplished through:
gene induction (by inducer)
When controlling transcription initiation, when lactose is absent:
repressor molecule binds to operator region
When controlling transcription initiation, when lactose is absent and the repressor molecule binds to operator region this:
prevents RNA polymerase from beginning transcription process
When a repressor is bound to the operator region and preventing RNA polymerase from binding:
NO mRNA or enzymes are produced
Describe what occurs in a catabolic pathway when lactose is absent:
Repressor molecule binds to operator region, preventing RNA polymerase from beginning transcription = no mRNA or enzymes produced
Describe what occurs in a catabolic pathways when lactose is present:
Inducer molecule binds to/inactivates the repressor and stops it from binding to the operator region = increased transcription
When lactose is present in a catabolic pathway, resulting in increased transcription, ultimately:
enzymes are produced to break down lactose for sugars
Catabolic pathways: ______
Anabolic pathways: _______
gene induction (by inducer); gene repression (by corepressor)
Controlling transcription initiation in anabolic pathways is accomplished through:
gene repression (by corepressor)
Anabolic pathways use of gene repression via a corepressor is considered the:
default- mRNA is produced
When is gene repression via a corepressor turned on in anabolic pathways?
when tryptophan (end-product) is at very high levels
Discuss what happens in an anabolic pathway when tryptophan is at very high levels:
tryptophan will act as corepressor by binding to repressor, allowing it to bind to operator site
When tryptophan (at high levels) acts as a corepressor, this ultimately:
inhibits transcription
Genetic complementation is a genetic approach to studying:
bacteria pathogenesis
In our study, we studied Yersina psudotuberculosis genes that confer ____ on ____.
invasiveness on E. coli
List the first 4 steps of genetic complementation:
- Isolate DNA and cut into restriction fragments
- Splice (insert) donor DNA into the plasmid
- Introduce into recipient
- Enrich for invasive clones
In step 3 of genetic complementation “introduce into recipient”, why are we introducing the Y. Psuedotubercolisis plasmid into E. coli?
Because E. coli is not invasive, so if we can cause it to become invasive with fragments of yersinia DNA, we can identify the invasive gene
In genetic complementation, when we introduce the DNA into the recipient (E.coli), the plasmids will:
divide and replicate right along with E.coli
In step 4 of genetic complementation “Enrich for invasive clones”, what is the goal?
goal is to screen different Yersinia genes to determine which one can invade a mammalian cell
In step 4 of genetic complementation “Enrich for invasive clones”:
Certain ____ that have acquired a plasmid with the ___ gene for ____ will enter the mammalian cells
E. coli; Yersinia gene for invasiveness
In step 4 of genetic complementation “enrich for invasive clones”
What is added to kill all the E. coli cells that are outside the mammalian cells and why?
Gentamicin (antibiotic) is added to kill all E. coli cells that are outside the mammalian cells (because those did not invade)
In step 4 of genetic complementation “Enrich for invasive clones”
After the antibiotic is added to kill the non-invasive E. coli, what occurs next?
Mammalian cells are then washed off, lysed, and their contents (including any E. coli that invaded), are plated onto antibiotic petrie dish
In step 4 of genetic complementation “Enrich for invasive clones”,
After the mammalian cells are washed, lysed. They then are plated onto antibiotic petrie dish. What does this allow for?
This process allows for positive selection of the cells that contain the invasive gene/ antibiotic-resistance
In genetic complementation process, after the positive selection of the cells that contain the invasive gene/ antibiotic-resistance, what next occurs? (4 steps)
- generate DNA sequence = INV gene
- deduce protein coding region= invasin protein
- manipulate (mutate) gene further
- reintroduce into Yersinia
During genetic complementation process when manipulating gene further and reintroducing into yersinia, what is the first step to accomplish this?
- Inv gene is cloned into suicide plasmid for yersinia
During genetic complementation process when manipulating gene further and reintroducing into yersinia, following the Inv gene being cloned into a suicide plasmid for yersinia, what occurs next?
a majority of the INV gene on suicide plasmid is replaced with a kanamycin-resistance gene (Km^r)
During genetic complementation, when reintroducing the manipulated/mutated gene back into yersinia, the Inv on the suicide plasmid may be replaced with the Km^r gene. What will this mutation result in?
Loss-of-function mutation
During genetic complementation, when reintroducing the manipulated/mutated gene back into yersinia, the Inv on the suicide plasmid may be replaced with the Km^r gene resulting in a loss of function mutation, What will then be done with the plasmids containing the mutated copies?
suicide plasmids containing inv loss-of-function mutation is transferred from E. coli to yersinia
In genetic complementation when the suicide plasmid containing the inv loss-of- function mutations are transferred from E. coli to Yersinia, the suicide plasmid will:
replicate in E.coli but NOT replicate in Yersinia (so plasmids lost after next cell division)
In genetic complementation, in the final steps, what is needed to replace the INV gene in yersinia chromosome with the loss-of-function Inv allele from the plasmid?
Double recombination event
What is ultimately the final step of genetic complementation with yersinia?
Test Yersinia INV mutatnts and show that they DO NOT invade (due to loss-of-function mutation)
Genetic complementation is used to study:
bacteria pathogenesis
move from place to place within a genome; jumping genes:
transposons
Insertion of a transposon in a gene often creates a:
loss of function mutation
What marks the site of mutation in transposon-based methods?
transposon
Unlike simple transposons, composite transposons contain:
separate IS elements at either end and intervening genes in between
The intervening genes in between the IS elements in composite transposons are often responsible for:
drug resistance
Tn-phoA is an example of:
engineered transposon
Tn-phoA mutagenesis identifies ____ in vibrio cholera
virulence genes
Transposon-based methods function to identify:
virulence factors
In Tn-phoA mutagenesis, experimenters are looking for vibrio genes that are: (2)
- exported into perioplasm
- expressed under certain physiologic conditions
In Tn-phoA mutagenesis, experimenters are looking for vibrio genes under what physiologic conditions?
@ pH 6.5 and high osmolarity
What its the first step in Tn-phoA mutagenesis?
- introduce Tn-phoA on a suicide plasmid
In Tn-phoA mutagenesis, when we introduce Tn-phoA on a suicide plasmid, the transposon may:
jump into vibrio chromosome (transposition)
In Tn-phoA mutagenesis, after Tn-PhoA is introduced on a suicide plasmid, we use ____ to select for cells containing a transposon (as some transposons jumped into the Vibrio chromosome)
Kanamycin
In Tn-phoA mutagenesis, what is required for colonies to grow?
kanamycin-resistance
In Tn-phoA mutagenesis, the third step is to screen for blue colonies, what are we looking for?
phoA+ gene
In Tn-phoA mutagenesis, phoA encodes the enzyme:
periplasmic phosphatase
In Tn-phoA mutagenesis, the expression of phoA gene depends on:
fusion of reading frame to an adjacent gene (V. cholera) AFTER transposition
In Tn-phoA mutagenesis, expression of phoA gene depends on fusion of the reading Fram to an adjacent gene (vibrio cholera) AFTER transposition. What does this fusion do?
This fusion tells the protein to go into the periplasm
In Tn-phoA mutagenesis, why do we see a blue color only if the cell was exported into the periplasm?
PhoA enzyme will cut the X-P dye to produce a blue color ONLY if the cell was exported
In Tn-phoA mutagenesis, PhoA is expressed ____ of bacterial cells.
outside
In Tn-phoA mutagenesis, within the blue colonies, ______ is no longer present
Tn-phoA plasmid
In Tn-phoA mutagenesis, after screening for blue colonies (phoA +), what is measured in the next step?
Measure phoA activity after growth in liquid medium
In Tn-phoA mutagenesis, after measuring phoA activity following growth in a liquid medium, we will ONLY select for bacteria that have have ____ activity at pH 6.5 and _____ osmolarity while having ____ activity at pH 8.0 and ___ osmolarity.
high; high
low; low
The final step in Tn-phoA mutagenesis is to:
test virulence in mouse model
In Tn-phoA mutagenesis, what should we expect to see when testing virulence in a mouse model?
Expect to see DECREASED virulence, because the transposon creates a loss-of-function mutation
What is used in the mouse model for typhoid fever?
signature tagged mutagenesis
Examines individual bacteria for a desirable trait:
genetic SCREEN
only bacteria with desirable trait grow:
genetic SELECTION
Genetic screening is based on:
phenotype (color, something you can see)
Genetic selection is based on:
what survives vs. what dies (antibiotic resistance)
Signature-tagged mutagenesis (mouse model for typhoid fever) is a ____ for a ____trait. Inability to grow in spleen.
screen; negative trait
What is the negative trait that is screened for in the signature-tagged mutagenesis (mouse model for typhoid fever)
inability to grow in the spleen
In signature-tagged mutagenesis (mouse model for typhoid fever) by screening for a negative trait (inability to grow in spleen), we are looking for:
mutants of salmonella that CAN’T infect a mouse
In signature-tagged mutagenesis (mouse model for typhoid fever): What is put into each transposon?
Km^r marker + DNA sequence tag (tiny variable region)
In signature-tagged mutagenesis (mouse model for typhoid fever), what is responsible for creating slight differences between the transposons?
PCR
In signature-tagged mutagenesis (mouse model for typhoid fever), After PCR of transposons, All the transposons are transferred into:
salmonella genome
In signature-tagged mutagenesis (mouse model for typhoid fever), All transposons are transferred into the salmonella genome by using a ____ that moves ____ from E. coli into salmonella
suicide plasmid; mini-Tn5
In signature-tagged mutagenesis (mouse model for typhoid fever), All transposons are transferred into the salmonella genome by using suicide plasmid that moves mini-Tn5 from:
E.coli to salmonella
In signature tagged mutagenesis: If transposition has occurred, all will have:
kanamycin resistance
In signature tagged mutagenesis: What do we select for after all transposons are transferred into the salmonella genome?
Kanamycin resistance
In signature tagged mutagenesis, selecting for kanamycin resistance will create:
a library of salmonella mutants that each contain a unique mini Tn5 insertion
In signature tagged mutagenesis, what do we inject the mouse with?
Pooled mutants
In signature tagged mutagenesis, once mouse is injected with pooled mutants, we then:
recover bacteria from the spleen
In signature tagged mutagenesis, what do we do with the recovered bacteria from the spleen and why?
place recovered bacteria on a kanamycin dish to identify those with transposon insertions
In signature tagged mutagenesis- What are the DNA sequence tags (variable region) used for?
used to compare the input and recovered pools of bacteria
In signature tagged mutagenesis, what do the blank spots in the covered pool blot represent?
bacteria mutants that did NOT grow in mice
In signature tagged mutagenesis, the mutants NOT recovered are:
avirulent
IVET:
In-Vivo Expression Technology
What mechanism is used in IVET?
Promotor trapping
In IVET we are looking for genes of salmonella that are:
expressed in infection but not in the lab
What is the first step of IVET?
- Put fragments of salmonella DNA into plasmid with PurA, LacZ, and ampicillin resistant gene
What type of plasmid is used in the first step of IVET?
Suicide plasmid
In IVET in the first step, what happens to the suicide plasmid?
undergoes double recombination
In IVET following the creation of a suicide plasmid containing salmonella, PurA, LacZ, and Ampicillin resistant gene, we engineer the bacteria further by inserting:
Loss-of-function PurA mutant
In IVET after further engineering the bacteria with a loss-of-function PurA mutant, what occurs?
Integration of plasmid onto chromosomes
In IVET after integration of plasmid onto the chromosomes, what is the following step>
Screen for PurA by injecting pool of fusions into mouse
In IVET once the mice have been injected with the pool of fusions, we then:
recover bacteria from spleen of mouse
In IVET, the bacteria recovered from mouse spleen must have:
functional promoter fused to PurA-LacZ operon because they were able to be recovered
Gene use to identify virulence genes that are transcriptionally active in the mouse: (IVET)
PurA
In IVET, the gene used to select for salmonella bacteria that contain the plasmid inserted within their genome
Ampicillin Resistance Gene
In IVET, after the bacteria have been recovered from the spleen, _____ is screened for in-vitro
LacZY
In IVET, the gene used to identify virulence genes that are not expressed during laboratory growth
LacZY
In IVET, ______ do NOT contain LacZ protein.
Light-colored colonies
In IVET, the light colored colonies that do NOT contain LacZ protein are the ones that are:
linked to a promotor expressed in infection (in mouse) but NOT in lab
DFIT
Differential Fluorescence Induction Technique
In DFIT what are we looking for?
Looking to identify genes continuing potential macrophage survival factors
(DFIT) _____ can survive within macrophages while ____ cannot.
Pathogenic salmonella; normal salmonella
In DFIT, fragments of ___ chromosome are placed into ____.
salmonella; GFP-fusion plasmid
(DFIT):
GFP can only be expressed if:
It is inserted next to a gene with an open reading Fram and promoter
In the second step of DFIT, macrophages are infected with transformed GFP salmonella and separated by:
fluorescence activated cell sorting (FACS)
In DFIT, what happens to the macrophages with fluorescent bacteria after separation via FACS?
They are lysed, grown on media, and then sorted again by FACS
In DFIT, why are cells ran through FACS a second time?
In order to identify bacterial cells that do NOT fluoresce on their own
In the final step of DFIT, what are we looking for?
bacterial cells that fluoresce within macrophages from the bacterial cell population that did not fluoresce when growing on their own in lab environment
IVIAT:
In vivo-induced antigen technology
IVIAT is an _____ approach
antibody-based
Uses patient serum to identify genes of bacterial pathogens expressed during infection
IVIAT
In IVIAT, what do antibodies typically respond to?
antibodies typically respond to protein on the surface or secreted by bacteria
In IVIAT, why do only some of the pathogen proteins react with patient serum?
Because only a subset of the pathogen proteins are secreted or expressed on the bacterial cell surface
In IVIAT, what vector is used?
bacteriophage
In IVIAT, the bacteriophages are placed into:
E.coli
In IVIAT, when the bacteriophages are put into & replicate in E. coli, what results?
zones of clearing
In IVIAT, what causes the zones of clearing?
Clear areas remain after local population of bacteria are lysed
In IVIAT, in addition to the zones of clearing, what else is present following the replication of bacteriophages in E. coli?
phage derby (plaque) and Recombinate bacterial proteins
In IVIAT, we remove intact E. coli because some antibodies will bind to the E. coli, we don’t want those antibodies, we only want:
antibodies for Tb
In IVIAT, we must remove antibodies from patient serum because antibodies will bind to each phase plaque replicate, generating a signal from all plaques, which would appear as:
black spots
In IVIAT, once you remove antibodies, the remaining serum is:
incubated with plaques on membrane filter
In IVIAT, the TB antigens will turn:
Black
In the microarray scheme, genes encoding potential virulence factors are identified by identifying:
genes whose mRNAs are expressed at different levels in bacteria growth in the lab compared to bacteria isolated from a patient
In the microarray scheme we convert ____ to ___, label with ____, and then mix ___ with array on glass slide.
RNA to DNA; fluorescent dye; copy-DNA
In the microarray scheme, PCR can be used to:
amplify individual coding regions of particular bacterial genome
Microarray Scheme:
Signal for a gene that has increased expression during infection:
Green fluorescent signal
Microarray Scheme:
Green fluorescent signal = singal for a gene that has increased expression during infection =
Cy3> Cy5
Microarray Scheme:
Signal for “house-keeping” gene expressed at the same level in choler both during an infection and during growth in lab
Yellow fluorescent signal
Microarray Scheme:
Yellow fluorescent signal = signal for “house-keeping” gene expressed at the same level in choler both during an infection and during growth in lab =
Cy3= Cy5
Microarray Scheme:
Signal for a gene that has an increased expression during growth in laboratory
Red fluorescent signal
Microarray Scheme:
Red fluorescent signal =signal for a gene that has an increased expression during growth in laboratory =
Cy5 > Cy3
Chemical compounds used to treat disease
chemotherapeutic agent
Destroy pathogenic microbes or inhibit their growth within host:
antimicrobials
Destroy or inhibit bacteria; a class of a chemotherapeutic agent:
antibiotics
Most antibiotics are _____ or their ____.
microbial products; derivatives
When bacteria produces material to kill each other and we those materials to kill bacteria:
germ warfare
What are some bacterial sources of antibiotics?
- streptomyces
- micromonospora
- bacillus
What are some fungal sources of antibiotics?
- penicillium
- cephalosporium
What are the four general characteristics of ANTIMICROBIAL drugs?
- selective toxicity
- therapeutic dose
- toxic dose
- therapeutic index
The ability of a drug to kill or inhibit a pathogen while damaging host as little as possible:
selective toxicity
Drug level required for clinical treatment:
therapeutic dose
Drug level at which drug becomes too toxic for patient: (i.e., produces side effects)
toxic dose
Ratio of toxic dose to therapeutic dose:
therapeutic index
What are the four general characteristics of ANTIBIOTICS?
- bactericidal
- bacteriostatic
- broad spectrum
- narrow spectrum
Kill bacteria:
bactericidal
inhibit growth of bacteria:
bacteriostatic
attack many different bacteria (gram positive and negative)
Broad-spectrum
attack many different bacteria (gram positive and negative)
Broad-spectrumA
Attack only a few different bacteria:
narrow-spectrum
How is the effectiveness of antimicrobial drug therapy expressed?
- minimal inhibitory concentration (MIC)
- Minimal bacteriocidal concentration (MBC)
Lowest concentration of drug that inhibits growth of pathogen:
minimal inhibitory concentration
Lowest concentration of drug that kills pathogen:
Minimal bactericidal concentration
What are the two techniques used to determine MIC and MBC?
- Dilution Susceptibility Test
- Disk Diffusion Test
Involves inoculating media containing various concentrations of drug:
Dilution susceptibility test
In a dilution susceptibility test, how do we know which is the MIC?
broth or agar with lowest concentration showing no growth
To introduce an infective agent or vaccine into organism/medium to produce immunity:
Inoculate
In a dilution susceptibility test, how do we know which is the MBC:
Broth from which microbe cannot be recovered
In a dilution susceptibility test, if broth is used, tube showing ____ can be subcultured into drug-free medium
no growth
Process in which disks impregnated with specific drugs are placed on agar plates inoculated with test microbe
disk diffusion test
How does a disk diffusion test work?
drug diffuses from disk into agar, establishing concentration gradient
In a disk diffusion test, what signifies no growth?
clear zones of inhibition around disk
What is the standardized method for carrying out disk diffusion tests?
Kirby-bauer method
In the Kirby-bauer method for carrying out a disk diffusion test, sensitivity and resistance are determined using tables that relate:
zone diameter to degree of microbial resistance
In the Kirby-Bauer Method for carrying out disk diffusion test, the table values are plotted and used to determine if:
concentration of drug reached in body will be effective
In the Kirby-Bauer method for carrying out disk diffusion test, the zone of inhibition depends on:
how effective the antibiotic is at stopping the bacterial growth
In the kirby-bauer method for carrying out disk diffusion test, a larger zone of inhibition =
smaller MIC
In the kirby-bauer method for carrying out disk diffusion test, designations are based on studies to establish:
the levels a drug can safety reach in the human bod
In the kirby-bauer method for carrying out disk diffusion test, what is considered RESISTANT:
What does this mean?
Less than 12 mm ; weaker antibiotic, requires higher concentration to stop growth
In the kirby-bauer method for carrying out disk diffusion test, what is considered SENSITIVE and what does this mean?
greater than 17mm; a stronger antibiotic
In order to be considered effective in the blood, concentration of drug at infection side must be:
Greater than or equal to the MIC
Describe the growth of colonies if antibiotics are effective:
No colonies will grow
What can be used to determine the concentration of drug in blood? (5)
Microbiological, chemical, immunological, enzymatic, or chromatographic assays
What are the three factors influencing the effectiveness of antimicrobial drugs?
- ability of drug to reach site of infection
- ability of drug to reach concentrations in the body that exceed MIC of pathogen
- Susceptibility of pathogen to the drug
The ability of the drug to reach site of infection depends in part on:
mode of administration
What are the three modes of administration of drugs?
- oral
- topical
- parenteral routes
What does parenteral routes of drug administration mean?
non-oral routes of administration
Orally administered drugs must be able to overcome:
stomach acid- some drugs are destroyed by this
What are two cases in which drugs can be exluded?
- blood clots
- necrotic tissue
The ability of a drug to reach concentrations in the body that exceed MIC of pathogen depend on:
- amount administered
- route of administration
- speed of uptake
- rate of clearance (elimination) from body
When discussing the susceptibility of a pathogen to drug:
A drug requires ___ to be effective
bacterial cell growth
How soon a drug stops bacterial growth:
speed of action
When discussing the mechanism of action of antimicrobial agents, the agent can impact the pathogen by targeting:
some function necessary for its reproduction or survival
Mechanism of action of antimicrobial agent:
Ideal, target function is:
very specific to pathogen
Mechanism of action of antimicrobial agent:
If targeted function is very specific to pathogen this means:
high therapeutic index
What are four mechanisms of action of antimicrobial agents?
- disruption of bacterial cell wall
- inhibition of protein synthesis
- inhibition of nucleic acid synthesis
- antimetabolites
Disruption of bacterial cell wall:
____ is unique to bacteria:
peptidoglycan
Disruption of bacterial cell wall:
Many antibiotics target this pathway:
peptidoglycan synthesis
Disruption of bacterial cell wall:
Acts as a carrier and links to NAM prior to addition of peptide side chain
Uridine Diphosphate (UDP)
Steps to peptidoglycan synthesis:
- Peptidoglycan repeat unit forms in ____
- Repeat unit then transported across membrane by ____.
- Repeat unit attached to ____ .
- Cross-links formed by ___ .
- cytoplasm
- bactoprenol (lipid)
- growing peptidoglycan chain
- transpeptidation
The exchange of one peptide bond for another:
transpeptidation
Inhibits transpeptidation:
B-Lactam antibiotics
What is an example of a B-lactamase inhibitor?
- clavulanic acid
- sulbactam
- tazobactum
Are not antibiotics but help B-lactam antibiotics by preventing their degredation by B-lactamases:
B-lactamase inhibitor
Enzymes produced by some bacteria that are resistant to B-lactam antibiotics
B-lactamases
Used in combination with B-lactam antibiotics:
B-lactamase inhibitor
The first combination of B-lactam antibiotic + B-lactamase inhibitors:
Specifically what was used?
Augmentin
amoxicillin + clavulanic acid
Binds terminal D-Ala-D-Ala and sterically inhibits the addition of peptidoglycan subunits to the cell wall
vancomycin
Vancomycin binding to existing peptidoglycan chains inhibits the:
transpeptidation reaction that cross-links the chains
Important for the treatment of antibiotic resistant staph and enterococcal infections:
vancomycin
Penicillins
Cephalosporins
Carbapenems & Monobactams
are all:
B-Lactams
Vancomycin & Teichoplanin are both
Glycopeptides
Bacitracin & Polymixins are both:
Polypeptides
Polypeptides, Glycopeptides, and B-Lactams are all responsible for:
disrupting cell wall
Second line treatment for mycobacterium tuberculosis:
Cycloserine
Sulfonamides, Trimethoprim, Dapsone, P-aminosalicyclic acid are all:
anti-metabolites
Unlike bacteria, humans do not make ____, we require it in our diet
folic acid
Antimetabolites act to inhibit ___ in bacteria
folic acid synthesis
Once resistance originates in a population, it can be transmitted to other bacteria via:
- new mutations
- pre-existing resistance genes
Resistance mechanism:
Hydrolysis of B-Lactam ring by B-lactamase:
Plasmidborne?
Penicillins & Cephalosporins
yes
Resistance mechanism:
Change in penicillin-binding protein:
Plasmidborne?
Methicillin
No
Resistance mechanism:
Efflux pump pushes drug out of cell:
Plasmidborne?
Tetracyclines
yes
Resistance mechanism:
Mutations in 23S rRNA:
Plasmidborne?
Oxazolidinones
no
Resistance mechanism:
Mutations in genes encoding DNA gyrase and topoisomerase IV
Plasmidborne?
Quinolones
No
Resistance mechanisms: How do bacteria resist antibiotics?
- impermeable barrier
- target modification
- antibiotic modification
- efflux pump mechanism
Resistance mechanism in which the bacterial cell membrane develops an impermeable barrier which blocked antibiotics:
impermeable barrier
Resistance mechanism in which modification of components of the bacteria which are targeted by the antibiotic, meaning the antibiotic can no longer bind properly to its target in order to destroy the bacteria:
target modification
Resistance mechanism in which the cell produces substances, usually an enzyme that inactivate the antibiotic before it can harm the bacteria:
antibiotic modification
Resistance mechanism in which the antibiotic is actively pumped out of the bacteria so that it cannot harm the bacteria:
efflux pump
Genetic elements involved in resistance gene dissemination include:
- plasmids
- transducing bacteriophage
- bacterial chromosomal genes
- transposons
- Integrons
Genetic elements involved in resistance gene dissemination:
Some plasmids can promote their own transfer by:
conjugation
Genetic elements involved in resistance gene dissemination:
Some transducing bacteriophage can package non-phage DNA resulting in transfer by:
transduction
Genetic elements involved in resistance gene dissemination:
Bacterial chromosomal genes can undergo ___ or transfer by ____.
mutations; transformation
Development and spread of drug-resistant pathogens caused by drug treatment, which destroys sensitive strains:
superinfection
What steps can be taken to prevent emergence of drug resistance?
- give drug in high concentrations
- give 2 or more drugs at the same time
- use drugs only when necessary
What are two possible future solutions for preventing emergence of drug resistance?
- continued development of new drugs
- use of bacteriophages to treat bacterial disease
Common organisms in superinfections include:
- C-diff
- MDR gram negative rods
- MRSA
- candida
Resistance to infectious disease:
immunity
Collection of cells, tissues, and molecules that mediate resistance to infections
immune system
Coordinated reaction of the immune system to infectious microbes
immune response
study of the immune system, including its responses to microbial pathogens and damaged tissues and its role in disease
immunology
Immune response that acts immediately
Innate
Immune response that is NOT antigen specific
Innate
Innate immune response recognizes ____ that are shared by many different microbes, as well as _____.
PAMPs & DAMPS
Pathogen Associated Molecular Patterns:
PAMPs
Damage Associated Molecular Patterns:
DAMPs
Genes encoding pattern recognition receptors (PRRs) are present in the:
germ line
Genes encoding receptors that recognize PAMPs are present in the germ line and do not under go:
somatic recombination or hyper mutation
In response to infection, innate immune cells do NOT undergo:
clonal expansion
Immune charaterized by no memory and cells that are not reactive to self:
Innate
The adaptive immune system requires ___ before it is effective
days to weeks
The adaptive immune system is highly:
antigen-specific
The adaptive immune system recognizes ____ on ____ of _____
specific epitopes; specific proteins; specific pathogens
In the adaptive immune system, functional genes encoding antigen receptors are:
NOT present in the germ line
In the adaptive immune system, functional antigen receptor genes are generated by ___ and ___ of germ line genes during maturation of B cells and T cells.
somatic recombination & mutation
In the adaptive immune system, the functional antigen receptor genes that are generated by somatic recombination and mutation of germ line genes, are produced:
prior to exposure to any antigens
In the adaptive immune response, clonal selection and proliferation of B and T lymphocytes specific for particular antigens occurs:
following exposure to those antigens
The adaptive immune response is ____ to self
non-reactive
Gives rise to immunologic memory:
adaptive immune system
Innate or Adaptive:
Provide initial defense against infections
innnate
Innate or Adaptive:
Develops later and is mediated by lymphocytes and their products
Adaptive
Innate or Adaptive:
Some mechanisms (epithelial barriers) prevent infections
Innate
Innate or Adaptive:
Other mechanisms (phagocytes, NK cells, complement system) eliminate microbes
Innate
Innate or Adaptive:
Involves humoral and cell-mediated immunity
adaptive
B-lymphocytes secrete antibodies that block infections and eliminate extracellular microbes:
Humoral immunity
____ secrete antibodies that block infections and eliminate extracellular microbes
B-lymphocytes
T-lymphocytes eradicate intracellular microbes
Cell-mediated immunity
T-lymphocytes eradicate ____ microbes (in cell-mediated immunity)
intracellular
Eliminate phagocytosed (ingested) microbes
Helper T cells
Kill infected cells and eliminate reservoirs of infection:
Cytotoxic T cells
Feature of adaptive immunity which ensures that distinct antigen elicit specific responses
specificity
Feature of adaptive immunity that enables the immune system to respond to a large variety of antigens
diversity
Feature of adaptive immunity that increases number of antigen-specific lymphocytes from a small number of naive lymphocytes:
clonal expansion
Lymphocyte clones with diverse receptors arise in primary lymphoid organs:
clonal selection
In clonal selection, lymphocyte clones with diverse receptors arise in:
primary lymphoid organs
A population of lymphocytes with identical antigen receptors (sam specificity); all derived from the same precursor cell:
Clone
In clonal selection, clones of mature lymphocytes specific for many antigens enter:
lymphoid tissue
In clonal selection, after entering lymphoid tissues, antigen-specific clones are activated by:
antigens
In clonal selection, what occurs when antigen-specific clones are activated by antigens?
stimulation of proliferation & differentiation of that clone
The secondary response to a specific antigen is:
large and more rapid (due to memory)
The primary response to a one antigen is:
different than to a different antigen (specificity)
Antigen recognition of B lymphocytes:
soluble or cell surface antigens
Effector function of ______ includes:
Secretion of antibodies:
- neutralization of microbe
- phagocytosis
- complement activation
B-lymphocytes
Antigen recognition of helper T cells:
antigens on surfaces of APC
The effector function of ____ includes:
Secretion of cytokines:
- activation of macrophages
- inflammation
- activation of T & B lymphocytes
helper T-cells
Antigen recognition of cytotoxic T-cells:
Antigens in infected cells
The effector function of ____ includes:
Killing of infected cells
Cytotoxic T cells
Regulatory T cells function to:
Surpress immune response
Antigen recognition of of natural killer cells:
Recognize change on surface of infected cells
Natural killer cells respond by:
killing infected cell
After lymphocytes are activated by antigen, ____ cells migrate towards each other and meet at the edge of follicle
B & T cells
After lymphocytes are activated by antigen, B & T Cells migrate towards each other and meet at the edge of follicle and there, helper T cells interact with and help B cells:
differentiate into antibody producing cells
- innate defensive mechanisms to keep out microbes
- if defensive barriers are crossed = inflammation & antiviral mechanisms
Early innate immune response
Secreted antibodies, phagocytes & helper T cells, cytotoxic T cells:
adaptive immune response
Includes microbial antigen from vaccine or infection
active immunity
Is active immunity specific? Does it cause memory?
Yes & Yes
Includes serum antibodies from immune individual administered to uninfected individual:
passive immunity
Is passive immunity specific? Does it cause memory?
Yes and yes
In innate immunity, specificity is based on:
PAMPs and DAMPs
In adaptive immunity, specificity is based on:
structural details of microbial molecules (antigens)
The receptors of the innate immune system are encoded in the:
This results in:
germline; limited diversity
The receptors of the adaptive immune system are encoded by:
This results in:
genes produced by somatic recombination; greater diversity
The distribution of receptors in the innate immune system are:
non-clonal
Identical receptors on all cells of the same lineage:
nonclonal (seen in innate immunity)
The distribution of receptors in the adaptive immune system are:
clonal
Clones of lymphocytes with distinct specificities express different receptors:
clonal (seen in adaptive immunity)
The two principal types of reaction of the innate immune system are:
- stimulate acute inflammation
- anti-viral defenses
The accumulation of leukocytes, phagocytic cells, plasma proteins, and fluid derived from the blood at an extravascular tissue site of infection or injury:
acute inflammation
NK cell-mediated killing of virus-infected cells
anti-viral defenses
Interferon A/B (Type 1 interferons), are secreted by virus-infected cells, bind to receptors on surrounding cells, and induce an antiviral state in those cells:
anti-viral defenses
List the prominent cell-associated pattern recognition receptors and sensors of innate immunity:
- Toll-Like Receptors (TLRs)
- NOD-like receptors (NLRs)
- RIG-like receptors (RLRs)
Where are the prominent cell-associated pattern recognition receptors and sensors of innate immunity located?
extracellularly in the cytoplasm or in endosomes
TLRs that recognize microbial products (such as PAMPs) will be found in the _____ ,while TLRs that recognize nucleic acids will be present within the _____
cytoplasm; endosome
TLR engagement by bacterial or viral molecules ultimately leads to:
- acute inflammation
- stimulation of adaptive immunity
- antiviral state
A family of more than 20 different cytosolic proteins that recognize PAMPs and DAMPs in the cytoplasm and recruit other proteins to form signaling complexes (such as inflammasomes) that promote inflammation:
NOD-like receptors (NLRs)
Cytosolic sensors of viral RNA that respond to viral nucleic acids by inducing production of the antiviral type 1 interferons
RIG-like receptors (RLRs)
Physical barrier to infection:
epithelial barrier
- Killing of microbes by locally produced antibiotics & killing of microbes and infected cells by intraepithelial lymphocytes are both functions of the:
epithelial barrier
- secrete cytokines that induce inflammation and ingest and destroy microbes
macrophages (can survive long periods of time in tissues)
- circulating phagocytic cells
- most abundant leukocyte in blood
- first responder to most infections
- live only a few hours in tissues
neutrophils
What happens to blood monocytes after entering into tissues?
differentiate into macrophages
What cells are the phagocytes of the innate immune response?
neutrophils and monocytes/macrophages
- microbes binding to TLRs
- cytokines binding to cytokine receptors
- complement fragments binding to complement receptors
These all cause:
activation of macrophages
Component of the innate immune system:
- secretes cytokines
- presents antigenic peptides to T cells
Dendritic cells (sentinel cells)
Component of the innate immune system:
- abundant cytoplasmic granules
- present in skin and mucosal epithelium
- contain vasoactive amines (e.g. histamine)
- cause vasodilation and capillary permeability
mast cells
Component of the innate immune system:
- lymphocyte-like cells
- produce cytokines but lack T-cell antigen receptors (TCRs)
innate lymphoid cells
Both mast cells and dendritic cells are part of:
innate immune system
Induce inflammation, opsonize microbes enhancing their phagocytosis, cause osmotic lysis of microbes:
complement
List the complement proteins involved in the early steps and late steps:
early steps: C3a, C3b
late steps: C5a, C6-C9
C3a is responsible for:
inflammation
C3b is responsible for:
opsonization and phagocytosis
C5a is responsible for:
inflammation
C6-9 are responsible for:
lysis of microbe
- rolling
- integrin activation by chemokines
- stable adhesion
- migration through endothelium
These are the steps in:
migration of blood leukocytes to site of infection
- kill virus-infected cells
- secrete interferon Y which activates macrophages
natural killer cells
secreted by virus-infected cells, induce anti-viral state in surrounding cells (local)
IFN a/b (Type 1 interferons)
_____ & _____ are combated mainly by an acute inflammatory response, in which neutrophils and monocytes are recruited to the site of infection, and by the complement system
extracellular bacteria & fungi
_____, which can survive inside phagocytes, are eliminated when the microbial killing functions of phagocytes are activated by TLRs and other sensors, as well as by cytokines
Intracellular bacteria
Defense against ___ is provided by type 1 interferons (interferons a & b) and by natural killer (NK) cells
viruses
