Micro 106 Exam 4

How is the cell wall affected by different agents?

damaged

* blocks synthesis or it is digested

How is the cytoplasmic membrane affected by different agents?

disrupts the lipid layer and allows things to enter and exit

How is cellular synthesis affected by different agents?

interrupts the synthesis of proteins via ribosomes

* inhibits proteins needed for functions
* changes genetic code

How are proteins affected by different agents?

denatures proteins or attaches to active site of protein preventing it from interacting properly

what are things to consider with chemical agents?

* effectiveness
* time to work
* effects on surface
* toxicity
* cost
* degradation

what is the phenol coefficient

* used to measure effectiveness of cleaning agent
* phenol (carbolic acid)

what is permeant destruction by antibiotics

bacteriocidal

* kills microbes directly
* only works on metabolically active microbes

what is temporary reduction by antibiotics

bacteriostatic

* cuts down # and relies on immune system

what factors affect the ability of chemical to destroy germs

* type of material being treated
* degree of contamination
* time of exposure
* strength of germicide
* MOA of germicide

how does soap work

partially pH, partial disruption of membranes

* soap doesn’t need additional elements added

why are soap dispensers better than bars

microbes can live on soap bars

what is detergent for cleaning

can be referred to as Quaternary Ammonium Compounds

* used to kill viruses , bacteria, and mold
* cleans a disinfects
* less effective in presence of organic material

what are halogens

* on periodic table
* harsh, commonly toxic

what are heavy metals

* Ag/Au
* used in fillings (don’t degrade)
* silver nitrate: rinse eye of newborns
* selenium: shampoo for dandruff

what are alcohols for cleaning

* solubilize cell membranes
* denatures proteins
* when mixed with water can be more effective

what are phenols for cleaning

* solubilize cell membrane and denature proteins
* Lysol derivative
* benefit: disinfection lasts for hours/days
* creosote: black/brown on railroad ties/poles

what are oxidizing agents for cleaning

H2O2: toxic to cell

* O2 in certain forms: very damaging
* peroxide

what are aldehydes for cleaning

formaldehydes, glutaraldehyde

* rapid inactivation of enz in cell
* works well on organisms resistant to chem control methods
* toxic
* slow release

what are gaseous compounds for cleaning?

ethyl oxide

* only chem that is sterilant
* will sterilize plastic or drugs
* toxic
* used in chamber that holds the gas, no heat

how do antibiotics work

toxic to pathogen, selective toxicity, internal

what are the two effects antibiotics can have on bacteria?

* bacteriostatic
* bactericidal

what is selective toxicity

act on structures unique to bacterial cells

what do antibiotics target

* cell membrane synthesis
* cell membrane function
* protein synthesis
* nucleic acid synthesis
* bacterial enz/metab pathways

what are two antibiotics at cell wall

* penicillin
* cephalosporin

how does penicillin work?

* interfere with cell wall by inhibiting peptidoglycan
* works best on cells building wall

what is cephalosporin

* next gen penicillin
* good against G+ / G-
* toxic to kidneys

what are antibiotics are active at cell membrane

* polymixin

what is polymixin

* integrates within outer membrane of G- bacteria
* membrane loses integrity as cell becomes sensitive to osmosis
* bactericidal
* last resort to drug resistance strains

what is bacteriocidal

can kill bacteria even if not actively growing

what are antibiotics affecting protein synthesis

* streptomycin
* tetracycline
* chloramphenicol

what is streptomycin

* disrupts bacteria reading of mRNA
* wrong amino acid placed in order

what is tetracycline

* binds to ribosome in bacteria and blocks tRNA binding
* only metabolically active cells
* teeth staining
* photosensitivity

what is chloramphenicol

* disrupts enzyme that forms peptide bonds
* older drug not used much due to resistance
* toxic effects at high pH

what are antibiotics that affect nucleic acid synthesis

rifamycin

what is rifamycin

* selectively binds to bacterial RNA polymerase
* works best on G+ cells
* red, change color of urine/sweat
* harmless

what are antibiotics that inhibit metabolism

metabolic antagonists: competitive inhibitors

* sulfonamides

what are sulfonamides

* interferes with bacteria ability to produce folic acid
* essential nutrient for naming RNA DNA
* doesn’t effect us b/c don’ make folic acid
* cause allergic reaction

what are characteristics of the idea antimicrobial drugs

* toxic to microbe nontoxic to cell
* microbicidal not microbistatic
* soluble
* doesn’t lead to resistance
* remains active in tissue/fluids
* easily delivered
* doesn’t bother host

what is prophylaxis

use of a drug to prevent infection of a person at risk

what is antimicrobial chemo

use of drugs to control infection

what are antimicrobials

all-inclusive term for any antimicrobial drug

what are antibiotics

substance produced by natural metabolic processes of microorganisms . drugs targeting bacteria

what are semisynthetic drugs

drugs that are chemically modified in the lab after being isolated from natural source

what are synthetic drugs

drugs produced by chemical reactions

what are the first steps to treating with antibiotics

* ID microorganism
* determine microorganisms susceptibility
* overall medical condition of patient

what are two reasons for resistance

* arms race (mutations during cell division or exposure to mutagen)
* bacteria undergo transformation, conjugation, transduction, or plasmid

what are resistance mechanisms

* attack antibiotic
* resist entry of antibiotics
* remove antibiotic from cell
* change antibiotic binding site
* alter metabolic pathways

what is meant by attacking the anitbiotic

* organic molecule with specific shape/fxn
* bacteria enzyme break bonds and destroy molecule

what is meant by resist entry of antibiotic

* bacteria mutate and change receptors on cell surface
* antibiotics unable to bind and gain entry

What is meant by remove antibiotic from cell

mutation may allow membrane protein to expel antibiotic that make it inside

what is meant by changing antibiotic binding site

* antibiotic bind to prokaryotic structure
* prevents binding from occurring

what is meant by altering metabolic pathways

* sulfonamides disrupting folic acid synthesis
* some bacteria can use alternate pathways to production

what is the lymphatic system

* collects excess fluids from blood and tissues
* also collects whatever else may be contained within

where is the fluid in the lymphatic system from

* endothelial cells of lymph vessels let fluid in, not out
* tissue without blood vessels → no lymph vessels

why would capillaries leak

* blood pumped under pressure
* fluid leaks out and needs to be returned
* part f the job of lymphatic system
* one way valves OUT ONLY

where are lymph nodes

primarily neck and groin

what is the thymus

* site of T-cell maturation
* largest and most active during childhood
* build immunity

what is a T-cell

* produced in bone marrow
* move to thymus to become fully functioning immune cells

what is the largest lymph organ

spleen

what does the spleen do?

screen blood

* acts as lymph node
* removes old blood cells
* b-cell activation location

what takes over if the spleen is removed

red bone marrow and live take over function

is the immune system one of the 11 systems of the body?

no!

what is the function of the immune system

* keep foreign invaders out
* recognizes self from non-self

what are antibodies

proteins produced by immune system to attack invaders

what is an antigen

* antibody generator
* body recognizes and non-self and attacks
* each has specific 3D shape

what are the 2 types of pathogens?

true and opportunistic

what is a true pathogen

fully capable of causing illness/diseases on their own

can overcome body’s defense

what are opportunistic pathogens

cannot make someone sick unless there are pre-existing conditions

immunological specificity

* immune system specifically targets individual invaders
* each cell has distinctive shape in cell membrane

what is MHC complex

* marker
* found in all cells of host
* how self is distinguished

what is immunological memory

* body can “remember” a disease
* next exposure causes quick response

what do chemical and physical non-specific barriers do?

* prevent invaders from gaining entrance in body
* nothing specific targeted

what is the role of skin

* covers internal tissue and keeps pathogens out
* microbial growth inhibited on surface by low moisture, low pH, and oily reside

what is the role of lysozyme

* enzyme with antibacterial properties
* tears: reduce eye infection
* saliva: prevent oral cavity bacteria

what is the role of normal flora

* harmless bacteria living on skin and GI tract
* compete with pathogens for food/space
* keep bad bacteria at low population

what is the role of stomach acid

* prevent most intestinal illnesses
* few bacteria an get past stomach to intestine

what is the role of urinary tract

* low pH, high salt helps prevent microbes from getting to bladder
* cranberry juice increases acidity of urine

what is the role of macrophages

* immune cells found in tissues and screen for invaders

what do macrophages secrete

interleukin 1

what does interleukin 1 do

* signals for WBC to come
* causes drowsiness and fever

what is acute inflammation

* caused by damage that kills cells in a tissue


* clotting

what do mast cells release

histamine

what do specific responses do?

* target particular antigens
* cell mediated
* antibody mediated

cell mediated

t-cells

antibody mediated

b-cells and antibodies

what are pro-inflammatory cytokines

encourage adaptive and innate immune response

what are anti-inflammatory cytokines

discourage adaptive and innate immune response

what are vasodilators and vasoconstrictors

change the diameter of blood vessels or vessel permeability

what are growth factor cytokines

regulate lymphocyte growth and activation

what is second line defense

* phagocytosis
* inflammation
* fever
* antimicrobial products

what are complement proteins

* groups of proteins found in blood
* can attack bacteria with attached antibody

what are lymphokines

chemical signals used by immune cells to coordinate attack

* interleukin and interferon

what is an antibody-mediated response

* bacteria or parasite infections
* bacterial toxin from other sources
* viral infections when virus leave the host

what are cell-mediated responses

* cells infected by virus
* cancer cells
* transplanted cells

what are the 3 types of t cells

helper, regulatory, cytotoxic

what are helper t cells

* activate macrophages
* assist b-cell processes
* help activate cytotoxic t-cells

what are regulatory t-cells

* control t-cells response through cytokines
* prevent proliferation

what are cytotoxic t-cells

destroy foreign or infected host cells

what are the steps of b-cell response

1. when activated by antigen, divides, and forms plasma cells
2. plasma cells release antibodies into tissues and blood
3. antibodies attach to specific antigen and target for destruction

what produce antibodies/immunoglobulins

mature B cells