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Microbiology Exam 2
7-17 and labs
214
Biology
Undergraduate 1
04/14/2009

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Term
Nutrients
Definition
the chemical substances which the microbe needs for cellular activities
Term
Elements
Definition
Carbon, Hydrogen, Oxygen, Phosphorous, potassium (K), Iodine, Nitrogen, Sulfur, Calcium, iron (Fe), Sodium, chlorine (Chloride), magnesium (Mg = Mighty good)

( CHOPKINS Café, Sodium Chloride Mighty good! )
Term
Essential nutrients
Definition
must be provided to the microbe to sustain life and allow growth
Term
chemotroph
Definition
gain energy from chemical compounds
Term
phototroph
Definition
gain energy through sunlight, photosynthesis
Term
Autotroph
Definition
can use CO2 as sole source of carbon
Term
Chemoautotroph
Definition
an organism that relies upon inorganic chemicals for its energy and carbon dioxide for its carbon
Term
Lithoautotrophs
Definition
"eat rocks"; inorganic diet
Term
Heterotroph
Definition
uses sources of carbon other than CO2 for metabolism and biosynthesis needs
Term
Chemoheterotroph
Definition
relies upon organic compounds for carbon and energy needs
a. Fermentation
b. Aerobic respiration: (use O2 as ultimate electron acceptor)
Term
Fastidious
Definition
require complex nutrients or growth factors
Term
Growth Factors
Definition
essential organic compound which is needed by the microbe, but cannot be produced by that microbe.
Term
Saprobes
Definition
normally feed on non-living organic material
Term
Phagocytosis
Definition
larger particles
▪ Pseudopod extensions encircle
Term
Pinocytosis
Definition
fluids and molecules
▪ Microvillius extension(s) surround droplet
▪ Oil droplets (lipids) can just fuse with or go through membrane (hydrophobic)
Term
Extracellular digestion
Definition
Digest outside of the cell and transport in small molecules into the cell across the cell membrane
Term
Active transport
Definition
a. Active transport
▪ Carrier-mediated; i.e. pump protein
▪ Energy required for transport proteins to change shape and “force” the nutrient molecule across the bilayer. (Fig. 7.7)
b. Group translocation – nutrient molecule may be chemically altered as part of the transport process. e.g. addition of phosphate group
c. Bulk transport – endocytosis, exocytosis
Term
Isotonic
Definition
similar concentrations of solute inside vs. outside
Term
Hypotonic
Definition
low outside solute/salt concentration
Term
Hypertonic
Definition
high outside solute concentration
Term
Psychrophile
Definition
▪ Range of temperatures between with a microbe can grow < 15°C
Term
Mesophile
Definition
▪ Range of temperatures between with a microbe can grow normally 20–40°C
** most medically relevant group
Term
Thermoduric
Definition
can survive short exposures to higher temps
Term
Psychrotrophs or facultative psychophiles
Definition
can grow slowly at lower temps even though they are mesophiles
Term
Thermophile
Definition
▪ Range of temperatures between with a microbe can grow > 45°C
Term
Microaerophile
Definition
needs oxygen, but requires reduced levels of oxygen
Term
Strict or obligate anaerobe
Definition
cannot tolerate any free oxygen; will die if exposed to oxygen

superoxide dismutase (O2–>H2O2) catalase (H2O2->2H2O)
Term
Aerotolerant anaerobes
Definition
don’t use O2, but are not harmed by its presence
Term
halophiles
Definition
live in high salt conditions without shriveling up
Term
Symbiosis
Definition
beneficial relationships between organisms
Term
Mutualism
Definition
reciprocal, obligate, beneficial
Term
Commensalism
Definition
= one benefits and doesn’t harm other
Term
Synergism
Definition
cooperation
Term
Antagonism
Definition
competition and inhibition by opposing organisms, each of which is capable of independent growth
Term
Quorum sensing
Definition
microbial “communication”
▪ Allows for self-monitoring of cell density (population growth)
▪ Secretion of chemical signals – following attachment to a surface, microbe secretes an inducer molecule;
▪ more inducer present = greater population
▪ inducer molecules can stimulate expression (“turning on”) of specific genes
▪ Genetic activation – when quorum (“critical mass”)is reached (i.e. inducer build-up) changes in gene expression occur.
▪ =coordinated expression of digestive enzymes, toxins, etc.
Term
Binary fission
Definition
Grow population by cellular division
Term
Lag phase
Definition
slower rate of cell division AS the microbe “recognizes” and adapts to fresh growth-promoting environment
Term
Exponential phase
Definition
rapid doubling rate; plenty of nutrients and space; few cells are dying
Term
Stationary phase
Definition
nutrient/space limitations; sense crowding; death of cells offsets new cell numbers formed by division;
▪ NET viable cell concentration in culture remains constant
Term
Death phase
Definition
more cells die than are replaced by division
Term
Metabolism
Definition
refers to the large variety of enzymatic reactions constantly occurring in the cell to make (synthesize) and/or degrade (utilize, catabolize) nutrients.
Term
Metabolites
Definition
compounds resulting from complex set of cellular enzymatic reactions
Term
Enzyme
Definition
biological catalyst (usually proteins)

increase the rate of a chemical reaction
▪ is NOT a reactant (substrate) or product
▪ is NOT consumed as part of the reaction
Term
Labile
Definition
subject to inactivation; chemically unstable
Term
Denaturation
Definition
weak bonds and interactions which hold protein in its native shape are broken
Term
Apoenzyme
Definition
the naked (folded) polypeptide chain(s)
Term
Holoenzyme
Definition
Apoenzyme + other essential non-protein components
Term
Coenzyme
Definition
organic molecule used/needed by the apoenzyme to do the catalysis (Vitamins)
Term
Cofactor
Definition
usually refers to a metal ion needed for the apoenzyme to do the catalysis and is bound by/to the polypeptide chain. (Trace metals)
Term
constitutive
Definition
always present in cell and at relatively constant levels
Term
induced (inducible/regulated)
Definition
enzyme produced in high amounts only under appropriate conditions
Term
Synthesis (Condensation)
Definition
build larger molecules from smaller precursors
▪ usually involve condensation (joining reaction releases a water molecule)
Term
Hydrolysis (Degradation)
Definition
splitting of larger molecules, requiring a water molecule
Term
Transfer reactions
Definition
simple addition/removal of a functional group
e.g. Oxidoreductase (transfer electrons)
e.g. Dehydrogenase (transfer hydrogen with electrons)
e.g. Transferase (transfer functional groups; e.g. carboxyl, amino)
Term
Aerobic respiration
Definition
▪ Glycolysis  TCA Cycle  ETC (O2 is required for ETC to function)
Net total with TCA + ETC = 38 ATP


(Glycolysis itself does NOT require O2 )
▪ O2 is the final electron acceptor in ETC chain;
▪ continued TCA requires continued function of the ETC to regenerate NAD+.
▪ metabolic intermediates can be used to make proteins, lipids, carbohydrates
▪ Glucose + O2  CO2 + H2O + ATP
Term
Fermentation
Definition
▪ Incomplete oxidation or metabolism of glucose (or other sugars)
▪ O2 not required
▪ Organic molecules serve as final electron acceptors rather than O2
▪ Relatively small amount of ATP produced (only 2 ATP per glucose)
▪ Alternate (non- O2 requiring ) solution to regeneration of NAD+
Term
Anaerobic respiration
Definition
▪ Glycolysis  TCA Cycle  ETC (use of NO3, or other as final e– acceptor)

▪ O2 is not the final acceptor (another chemical such as nitrate)
Term
Glycolysis
Definition
REFERS to conversion of glucose to 2 pyruvates (pyruvic acid), anaerobic, ATP consumed = 2
Term
TCA cycle
Definition
▪ Enzymes located in: (1) matrix of mitochondria (eukaryotes)
(2) cytoplasm (prokaryotes)
6 CO2 used per glucose
Term
Electron Transport Chain and Oxidative Phosphorylation
Definition
▪ Enzymes embedded in: (1) mitochondrial inner membrane (cristae; eucaryotes)
(2) cell membrane (procaryotes)
End Goals:
(1) Convert reducing equivalents carried by NADH (and FADH2) into ATP energy

(2) Regenerate NAD+ (and FAD) – essential if glycolysis and TCA are to continue
Term
Chemiosmosis
Definition
as the series of carriers (cytochromes) shuttle electrons, they pump H+ ions
Term
Cyanide poisoning
Definition
– blocks last enzyme in transfer chain of ETC (cytochrome oxidase)
Term
Fermentation
Definition
: incomplete oxidation (use) of glucose or other carbohydrate (usually a sugar) due to the absence of oxygen (or absence of ETC capability)
▪ Net yield = 2 ATP per glucose
Term
Organic acid (usually one type ex. Lactic Acid), Mixed acids (Lactic Acid, Formic Acid ect.) , Not an acid (Neutral end product)
Definition
Other Options for Pyruvate Utilization
Term
Amphibolism
Definition
use of metabolites (intermediates) in anabolic and/or catabolic pathways
Term
Amination
Definition
make amino acid from sugar
Term
Transamination
Definition
make other amino acids(swap NH2)
Term
Deamination
Definition
(remove NH2) – allows amino acids to be used for energy production
Term
nucleosomes
Definition
beads on a string" DNA helix is wound around organization proteins called histones in structures further wrapped into higher order arrangements etc. (e.g. supercoiling)
Term
DNA Helicase
Definition
unwinds the helix and separates (“unzips”) strands
Term
DNA polymerase III
Definition
builds (polymerizes) new DNA strand by (1) aligning a nucleotide with the correct complementary base with the base in the template strand and (2) catalyzing the sugar-phosphate bond between nucleotides in the forming strand.
Read 3' to 5', Build 5’ to 3’
Term
Ribosomal RNA (rRNA)
Definition
join with protein subunits to form ribosome
▪ transcribed very actively
▪ genes encoding rRNA (on different chromosomes) are arranged to form nucleolus
Term
Messenger RNA (mRNA)
Definition
temporary copy of protein-encoding gene
Term
Transfer RNA (tRNA)
Definition
very small RNAs which are specifically linked to one of 20 different amino acids
▪ fold in hairpin loops to form cloverleaf-shaped structure
▪ contain anticodon – used by ribosomes as decoding tools to match codons (every 3 nucleotides in mRNA) with the proper amino acid.
Term
Promoter
Definition
DNA sequence that determines whether a gene will be transcribed
Term
Degeneracy
Definition
some amino acids can be “called for” by multiple different codons/ anticodons
Term
Substitutions (point mutations)
Definition
▪ Silent = no change in amino acid
▪ Missense = encode different amino acid
▪ Nonsense = creates a stop codon
Term
Frameshifts
Definition
an insertion/deletion of a DNA nucleotide into the DNA sequence; changes entire ‘downstream’ protein sequence
Term
▪ The AMES test
Definition
▪ Combine potential carcinogen with rat liver enzyme extract
▪ Add results of the “conversions” to special mutated strain of bacteria
Mutations that revert the his – gene to HIS+ allow individual bacterial cells to survive and form colonies
The more highly carcinogenic a chemical, the more colonies would form due to the increased potential to cause mutations
Term
polysomes
Definition
more than one ribosome is usually translating a given mRNA
Term
RNA Splicing
Definition
enzymes “clip” out introns, and join exons together
Term
Conjugation
Definition
bacterial sex: pilus-mediated transfer of plasmid or chromosome)
Term
Transformation
Definition
(uptake of naked DNA from solution by bacterial cell)
Term
Transduction
Definition
(virus involved in the transfer)
Term
Hfr transfer
Definition
F+ factor is in the host chromosome
Part of chromosome is transferred rather than the F+ plasmid
Term
Sterilization
Definition
any process that destroys or inactivates ALL viable microorganisms and/or viruses
Term
Sterile
Definition
condition of a material after it has been sterilized
▪ complete absence of living microbes or microbes capable of life
▪ for viruses: incapable of replication
Term
Disinfection
Definition
destruction of vegetative pathogens on inanimate objects.
Term
Antisepsis
Definition
use of chemical agents (antiseptics) to destroy/inhibit vegetative pathogens on body surfaces (skin, mucous membranes, wounds, surgical incisions).
Term
sepsis
Definition
growth of microorganisms or presence of toxins in blood or tissues
Term
Sanitization
Definition
cleansing, removal of debris, microbes, and toxins from inanimate surfaces to reduce potential for infection/spoilage
Term
Degermation
Definition
dramatically reduce numbers of microbes on living tissue (skin)
▪ typically combined with use of antiseptics
Term
(1) Time (not all cells of the same microbe will become inactivated simultaneously)
(2) Type (vegetative cells are more easily killed)
(3) Microbial load = number to start with (killing of higher numbers takes longer)
(4) Action of the Agent (-cidal vs. -static agent)
Definition
Conditions that influence ability to kill microbes
Term
Thermal death time (TDT)
Definition
shortest length of time required to kill microbes at a specified temperature
Term
Ionizing radiation
Definition
▪ gamma rays, x-rays
▪ impact forms ions, esp. chemically active ionized free radicals
▪ DNA breaks or major changes are lethal, so cell dies
▪ Applications: Food irradiation, mail, medical instruments
Term
Non-ionizing radiation
Definition
▪ UV light (lower energy, shallower penetration)
▪ excites atoms to higher energy state (doesn’t move electrons)
▪ Cause less dramatic chemical changes
▪ Crosslinking of nucleotide bases in DNA (Fig. 11.9)
▪ thymine dimers
▪ problems for DNA replication and cell division (eventually cell death)
▪ Applications: Treatment of municipal water supplies (Fig. 11.11), work surfaces
Term
Halogens
Definition
microbicidal; sporicidal with longer exposure
far right of periodic chart
Term
Phenolics
Definition
(aromatic rings like phenol) (Fig. 11.12)
▪ Mechanism: @ High conc. – disrupt cell wall/membrane
@ Low conc. – inactivates enzymes
▪ Toxic: many not useful as antiseptics
▪ not reliably sporicidal
Term
. triclosan
Definition
phenolic derivative that is widely used as disinfectant / antiseptic
antibacterial soap, deodorant
Term
Aldehydes
Definition
(glutaraldehyde, formaldehyde)
▪ chemically crosslink biomolecules so they cannot function
(disinfection of instruments or plastics)

▪ formalin = dissolved formaldehy
Term
GAS sterilization
Definition
ethylene oxide (ETO; see structure on page 336) – reacts with functional groups of DNA and protein
Term
Antimicrobial chemotherapy
Definition
use of chemical agents (drugs or antibiotics) to control infection
Term
Chemotherapeutic drug
Definition
any chemical used in treatment of, relief from, or prevention of disease
Term
Prophylaxis
Definition
use of treatment ahead of time to prevent infection or disease in person at risk
Term
Antibiotics
Definition
inhibitory compounds that are produced by natural metabolic processes by living organisms (usually microbes produce them to inhibit growth of other microbes)
Term
parenteral
Definition
beyond intestine = bypass gastrointestinal tract
injection into vein (intravenous)
injection in muscle (intramuscular)
apply to skin surface (topical)
injection beneath skin (subcutaneous) or body cavity (e.g. intraperitoneal)
Term
Beta-lactam group
Definition
three-carbon, one-nitrogen ring; interferes with proteins involved in synthesis of cell wall
▪ penicillins, Cephalosporins block crosslinking of peptidoglycan cell wall
Vancomycin, Bacitracin – hinders elongation of peptidoglycan
Isoniazid (INH) – works by interfering with mycolic acid synthesis; used to treat infections with Mycobacterium tuberculosis; oral doses in combination with other antimicrobials such as rifampin, ethambutol
Term
Polymyxins
Definition
intermix with, intercalate into, disrupt or weaken the phospholipid bilayer (cause leakage of proteins, nitrogen bases; esp. gram neg. bacteria)
Term
Quinolones
Definition
inhibits DNA gyrase/helicase ( DNA unwinding enzymes)
 stopping transcription
Term
Rifampin
Definition
inhibits RNA polymerase  block transcription (no protein production!)
Term
Aminoglycosides
Definition
cause misreading of mRNA Target 30s subunit (smaller one)
Term
Tetracyclines
Definition
– block attachment of tRNA to Acceptor site (A-site) Target 30s subunit (smaller one)
Term
Chloramphenicol
Definition
blocks formation of peptide bonds Target 50s subunit
Term
Erythromycin
Definition
inhibits translocation (shift) of ribosome to read mRNA Target 50s subunit
Term
Oxazolidinones
Definition
prevents initiation by blocking assembly of 50s and 30s subunits with the mRNA
Synthetic-last resort
Term
metabolic analogs
Definition
mimic the natural substrate and therefore vie for active site of enzyme and prevent it from binding substrate
Term
Trimethoprim
Definition
– inhibits subsequent step in folic acid synthesis
▪ use in combination with sulfa drugs
Term
Polyenes
Definition
complexes with the sterols on fungal membranes, disrupt membranes
Term
quinine, chloroquine
Definition
Antimalarial
Term
Metronidazole
Definition
amoebicide
Term
Tamiflu, Relenza
Definition
Block (complete) penetration into host cell
Term
Acyclovir
Definition
Block viral replication/transcription
▪ synthetic purine
▪ blocks DNA synthesis
Term
AZT (azidothymidine/Zidovudine)
Definition
Block viral replication/transcription
▪ thymine analog
▪ blocks Reverse transcriptase
Term
Protease inhibitors
Definition
Prevent particle maturation
Term
Interferon (IFN):
Definition
▪ Normally endogenous signal released by infected cells
▪ Induces antiviral (inhibitory) “programs” to turn on within neighboring uninfected cells
▪ Helps to enhance immune responses that can detect and destroy the virus and/or virus infected host cells
Term
intrinsic
Definition
some microbes are not sensitive to some drugs, naturally
Term
Drug inactivation , Decreased permeability or uptale, Change in number or affinity of drug "receptor" sites, Alternate metabolic pathway
Definition
Specific mechanisms of drug resistance
Term
Kirby-Bauer or disc diffusion technique ,
E-test: different concentrations of antibiotic as gradient on single test strip allows for calibration of MIC with single test.
Dilution testing
Definition
Testing for Drug Sensitivity & Safety
Term
Therapeutic Index
Definition
toxic dose/(minimum effective dose (MED))
Term
Infection
Definition
condition in which pathogenic microorganisms penetrate host defenses, enter tissues and multiply.
Term
Disease
Definition
any deviation from health
Term
lactase deficiency
Definition
leftover undigested lactose is catabolized by microbes leading to gas and cramps
Term
True Pathogen
Definition
capable of causing infection in “normal” healthy individuals
Term
Predispose
Definition
factors make it more likely that you will succumb to infection
Term
Virulence
Definition
degree of pathogenicity
Term
Virulence factors
Definition
factors which enable a microbe to invade the host and produce toxins/toxic effect
Term
toxemia
Definition
spread of toxin by blood
Term
intoxication
Definition
– toxin is injested (botulism food poisoning)
Term
toxinoses
Definition
diseases caused by toxins
Term
Focal infection
Definition
systemic seeding/progression from originally local infection
Term
Primary infection
Definition
– the initial infection
Term
Secondary infection
Definition
– subsequent infection allowed by altered host defenses
Term
Sign
Definition
objective, observable evidence (what someone else can see/measure)
Term
septicemia
Definition
– microbes present and multiplying in blood in large numbers
(you are in trouble!!)
Term
bacteremia
Definition
bacteria detected, but not necessarily multiplying
Term
viremia
Definition
virus is present/detected, but not necessarily multiplying
Term
Reservoir
Definition
habitat in natural environment from which pathogen originates
Term
Source
Definition
individual or object from which you actually obtain the infection
Term
Vector
Definition
live animal that transmits an infectious agent from one host to another
▪ Biological vector – participate in life cycle e.g. flea, mosquito, tick
▪ Mechanical vector – only transport e.g. houseflies, cockroaches
Term
Vehicle
Definition
– inanimate material e.g. food, water, tissues, fomites (inanimate objects)
Term
CDC (Center for Disease Control and Prevention)
▪ weekly Morbidity (death) and Mortality (sick) Report
WHO (World Health Organization)
Definition
reportable diseases are reported to these organizations
Term
Prevalence
Definition
number of existing cases / total population
Term
Incidence
Definition
number of new cases / number of healthy persons
Term
Endemic
Definition
relatively stable frequency of disease in a particular region
Term
Epidemic
Definition
any rise beyond what is expected for frequency within a population
Term
reticuloendotheilial system
Definition
network of fibrous connective elements occupies extracellular space
areas in which white blood cells can migrate and chemicals diffuse
extracellular fluids which surround individual cells
some space between edges of cells
Term
serum
Definition
plasma less cells, less clotting proteins
Term
chemotaxis
Definition
move in response to chemical signals
Term
diapedesis
Definition
migration between gaps in capillary endothelial cells
Term
Neutrophils
Definition
Phagocytosis (esp. bacteria)

increased neutrophil levels signal bacterial infection vs. viral infection
most numerous
(55-90%)
Term
Eosinophils
Definition
Few
(1-3%) Anti-helminth, anti-fungal
Term
Basophils
Definition
Rare
(<0.5%) Similar to mast cells in tissues.
Promote inflammation, etc.
Term
Granulocytes
Definition
▪ polymorphonuclear – characteristic multilobed nuclei
▪ named for abundant cytoplasmic granules which stain by Wright Stain procedure
Term
Agranulocytes
Definition
reportable diseases are reported to these organizations
Term
Monocytes
Definition
Few
(3-7%) Large oval or kidney-shaped nucleus
Very active phagocytes; immune regulation
Circulate only 1-few days  exit into tissues, differentiate into Macrophages
Term
Lymphocytes
Definition
2nd-most numerous
(20-35%) Specific immune response
B cells: [B = bursa, a gland in chickens]
production of antibodies
T cells: [T = thymus]
(1) control immune responses (activate or suppress)
(2) help B cells by producing cytokines
(3) kill infected host cells
Term
medulla
Definition
special epithelial cells in thymus that provide signals for T cell development
Term
cortex
Definition
undifferentiated T lymphocytes (thymocytes)
Term
pyrogens
Definition
chemicals which cause temperature increases
Term
phagosome
Definition
compartment in a macrophage or neutrophil where recently endocytosed materials are
Term
phagolysosome
Definition
oxygen radicals (“respiratory burst”)
other strong oxidizing agents
lactic acid, nitric oxide, lysozyme
all are combined with a phagosome making a ...
Term
Specific immune signal (classical pathway) = antibody targeting (an antibody which binds to foreign molecules on a cell surface and attracts C1)
Innate recognition (alternate pathway) = farther down on the pathway, the C3 form can bind to generic bacterial surfaces and trigger the pathway (innate)
Definition
two ways compliment can be triggered
Term
membrane attack complex
Definition
Final unit formed from compliment
▪ bores holes (pores) in cell wall/membrane
Term
antigen
Definition
substance which provokes an immune response; can be protein, glycoprotein, carbohydrate
Term
epitope
Definition
small portion of the antigenic substance
▪ the particular part of the antigen molecule that is actually "recognized by" (bound by) specific immune receptors/molecules like antibodies or T cell receptors
Term
Antibodies (B cell receptors):
Definition
can bind to intact antigen structures by binding to epitopes located within the antigen
Term
T cell receptors
Definition
can only bind to epitopes that have been removed from the original antigen structures (processing); the epitopes must be presented to the T cell receptors on host major histocompatibility proteins (presentation)
Term
Recombination of V-J-D Sequences
Definition
▪ occurs during B cell development
▪ genomic DNA of an individual B cell is randomly "cut and pasted" to give rise to a unique combination of gene sequences
Term
Plasma cells
Definition
Activated B-cell undergoes clonal expansion, multiplying and secreting large volumes of antibody (same specificity!) in soluble form
Term
Memory cells
Definition
Activated B-cell undergoes clonal expansion, multiplying and remaining (~20 yrs) for quick response to repeat infection
▪ memory B cells respond more readily than naïve/virgin B cells
▪ less requirement for T cells to help them upon repeat infection
Term
IgM
Definition
Produced at first response; secreted, Pentamer, B-cell receptor
Term
IgD
Definition
Receptor on B-cells
Term
IgG
Definition
largest class (80% of Ig), memory (repeat) response, crosses placenta
Term
IgA
Definition
Secreted; mucous membranes, glands (saliva, tears, mucous, milk)
Term
IgE
Definition
Allergy, worm infections (binds to mast cells & basophils)
Term
Neutralization
Definition
binds to surface so that pathogen becomes inactivated. esp. viruses
Term
Complement fixation
Definition
kills cells by specifically pointing out target to complement system
Term
Agglutination
Definition
crosslinking of large aggregates due to bivalency of antibody molecules; contains them; more attractive for phagocytosis; causes precipitation
Term
Opsonization
Definition
coating to facilitate phagocytosis
Term
Tolerance
Definition
Events in the thymus kill off T cells that can recognize self = host cell antigens/epitopes
Term
Major Histocompatibility molecules (MHC)
Definition
▪ cell surface proteins that (1) signify “self”
(2) present epitopes for immune surveillance
Term
Antigen processing
Definition
the process in which long polypeptide chains (protein antigens) are cleaved by proteinases into short peptides by the action of proteinases (proteases) inside of cells
Term
proteases
Definition
enzymes which cleave peptide bonds
Term
MHC Class I
Definition
almost all nucleated human cells (including phagocytes)
Proteins synthesized inside the presenting cell
(including normal host proteins, viral proteins, mutated cancer proteins)
8-10 amino acids
CD8+ T cells
Term
MHC class II
Definition
only phagocytic cells
▪ macrophages
▪ professional antigen presenting cells (APCs) e.g. dendritic cells
From outside of presenting cell (engulfed material)
12-20 amino acids
CD4+ T cells
Term
CD4+ = Helper T cells (TH)
Definition
produce cytokines which are NECESSARY growth and activation signals for…
(1) Macrophage activation:
Stimulate macrophages which have ingested bacteria – to produce higher levels of killing enzymes etc. (activated macrophages)

(2) Stimulate B cell division and differentiation:
Stimulate B cells which have been stimulated by antigen binding – to multiply, produce more antibody and secrete it (Cytokine = Interleukin-2)
(3) Stimulate B cell class switching e.g. IgM  IgG, etc.
▪ class switching accompanies additional mutations to antibody producing genes which lead to improvement of avidity of antibody for pathogen targets

(4) Stimulate TC cells:
Stimulate CD8+ cells which have bound appropriate antigen (with TCR) – to divide
Term
CD8+ = Cytotoxic (Killer) T cells (TC or CTL)
Definition
▪ Antigen-specific – must “see” proper antigen signal on cell surface (MHC I complex)

▪ Kill target cells: virus-infected host cells or cancer cells
▪ Release perforins (punch holes in target membrane) and granzymes (attack target cell intracellular proteins)
Term
Memory T cells (both CD4+ and CD8+)
Definition
pathogen-specific memory cells are later established; remain long term for future infections
Term
type I immune hypersensitivity
Definition
allergy, key is abnormally high levels of IgE antibody
IgE is produced on primary exposure to an antigen (allergen attaches by Fc region to mast cells in tissue locations
Term
type II immune hypersensitivity
Definition
recognition of cell-bound antigen by antibody
e.g. transfusion reactions: lysis of cells due to antibody recognition followed by activation of complement when inappropriate blood type is used for transfusion
Term
type III immune hypersensitivity
Definition
= responses to abnormal formation and deposition of immune complexes antibody-antigen complexes) formation of Ab-Ag complexes that form deposits
Term
type IV immune hypersensitivity
Definition
DTH (delayed type hypersensitivity) Fig. 16.5
may resemble a local skin allergy, BUT
occurs over a longer time period
involves T cell responses to processed antigens (peptides)
poison ivy
Term
serology
Definition
diagnostic testing of serum
Term
Agglutination testing / immune precipitation
Definition
antibody-antigen cross-links can form -so many interconnected cross-links form that visible clumps are formed
Term
Western blotting
Definition
electrophoresis, stamp onto membrane, antibody has bound to the membrane (test antibody linked to color-generating enzyme), dark blobs in given location (bands) indicate good reactivity or a lot of the target protein that was recognized by the test antibody
Term
Complement fixation
Definition
competition between antibodies which may be in patient serum and an anti-RBC control antibody that will bind to RBCs
Term
Immunofluorescence
Definition
making pathogens glow!
direct vs. indirect
Term
ELISA (enzyme linked immunosorbent assay)
Definition
detect presence of antigen-specific antibodies in serum of patient (a)
detect presence of antigen by using known antibody
Note use of Fc portion of antibody as second specificity handle
Term
Basic Dyes
Definition
crystal violet, carbolfuchsin, methylene blue
Term
bacterial smear
Definition
dried preparation of bacterial cells that have been lightly fixed onto a glass slide by gentle heating
Term
mordant
Definition
increases the interaction between the bacterial cell and the dye so that the dye is more tightly bound or the cell is more strongly stained
Term
presumptive test
Definition
dilutions from water sample are placed in lactose/lauryl trytose broth fermentation tubes (selects of gram -). check for lactose? or gas?
Term
confirmed test
Definition
highest dilution of gas+ and growth+ are inoculated into brilliant green lactose bile broth. gas+ = confirmation of coliforms
Term
completed test
Definition
coliform+ from green lactose bile broth is streaked on Levine's EMB or LES Endo agar. this is to isolate and characterize individual bacteria
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