big mechanism in the how chemical agents work. Destroys the proteins tertiary shape-non covalent bonds are being broken

ex: fried egg-the protein is permenantly denatured

warmed milk-the protein can be reconfigured, only temporary denaturation

membran alteration-allows penetration by reducing the surface tension

ex: greasy skillet- soap (surfactant) binds to the grease and disoldges it

surfactant binds to a cell and the cell dies

Heavy metal

Alochols

Phenol compounds (lysol)

Oxidizing agent (Hydrogen peroxide)

Soaps and detergents

Halogentated Compounds (iodine)

Heat

Autoclave

Pasterurization

Filtration

Radiation

Moist-boiling (more effective-penetrates better)

Dry- flame

One of the most popular ways to destroy microbes

Exposure to boiling water for 10 mins is sufficient to destroy vegetative cells and eukaryotic spores.

moist heat+pressure

kills spores

all air must be removed from the chamber-pressure is needed to break the spores.

invented by pasteur to destroy microbes that caused wine to sour-does not acheive sterility.

kills salmonella and mycobacterium

flash method-heated at high temp/short time

holding method- heated at lower temp/longer time

Ionizing radiation

excellent sterilizing agent because of its ability to penetrate deep into objects

-electrons are released from the atoms creating ions

will destroy bacterial endospores and both prokaryotic and eukaryotic vegatative cells

can be used to sterilize substances that are destroyed by heat (drugs, serum vitamins, sucrose)

helpful in making vaccines

anything bacteria produce that will kill or inhibit another organism

-anything of microbial origin

Summary of targets

-works in five ways

1. Inhibition of cell wall synthesis

2. Disruption of cell membrane function

3. Inhibition of protein synthesis

4. Inhibiton of nucleic acid synthesis

5. Action as antimetabolites

beta lactem ring

binds to enzymes involved in make the cross link in the cell wall-weakening the cell wall, the pressure on the inside of the cell is enough to destroy the cell.

toxicty

allergy

disruption of microflora

a gene has mutated and has an altered protein, the antibiotic doesnt recognize the protein

(specific resistance)

a single plasmid may carry the resistance gene for many products.

plasmids are scattered all throughout the cytoplasm

much more worrysome

-effective drug concentrations (improper dosages)

-restricting drug prescriptions (many prescriptions are given unnecessarily)

great 1st step in determining microbial sensitivites.

place disks of antibiotics into culture. done most often, but takes time.

culture could be classified as sensitive, intermediate or resistant.

Solubility

Selective Toxicity

Stable toxicity level

Allergenicity

Tissue Stability

Resistance Aquisition

Shelf life

Cost

Penicllins

Cephalosporins

=

all have the beta lactem rings

biosynthetic pathway

sulfa drugs mimic the intermediate in the production of folic acid-then stops production

tricks the cell into thinking it has the specifc part it needs but then stops-meaning the cell is missing that vital part to surive so it dies off.

beneficial

those organisms that we always have

occupies sites on our bodies so the bad bacteria cant bind

may colonize for a few weeks, and then leaves

bacterium that is usually apart of our normal flora and usually causes no harm. however if our body is compromised it can cause disease

candida albicans-yeast infections due to low number of lactobacillus.

doesnt follow the normal progression, organism may be carried for year before symptoms appear

-cold sores

-leprocy

-tuberculosis

-organism must get into the body, bind and replicate

-organism goes thru and incubation period

-clinical symptoms begin to show up

-recovery period

Invasivion

Toxin production

Endotoxin

(LPS)

only produced by gram (-) bacteria

when bacteria are lysed, endotoxin is released which causes a spike in fever

very broad-many different types, but each kind has a  specific mode of action (neurotoxins, enterotoxins)

gram (-) bacteria has endotoxins and exotoxins

chemically inactivated version of an exotoxin, still recognized by the body-body can build and immunity against it---used in vaccines

impossible to make toxoid out of endotoxin

Non-specific (innate) immunity

what we're born with

requires no previous exposure to organism

ex; lysozyme, skin, cilia, phagocytosis

Complement proteins

form of innate immunity

~20 proteins binds to surface of cell and punches holes in the suface

puts a red flag on the cell to enhance the ability of the phagocytes to recognize the intruder

is considered to be a specific and a non specific form of immunity

molecule that recognizes an antigen

made by a b-cell

requires previous exposure

includes b and t cells

responsible for cell-mediated immunity

useful for organisms that invade cells

3rd position in a codon

it doesnt usually matter what nucelic acid is in this spot because it will still attract the same tRNA and code the same amino acid

can bind w/ A,C,G, and T

lacks base pairing rules

initiation

elongation

termination

Initiation

30s ribosome binds to rbs

the first tRNA binds

50s ribosome binds

p, a, and e site are now present

for elongation to occur, the a site must be empty

incoming tRNA's enter thru the empty a site

starts when the a site is over a stop codon

there is nothing to bind to, so the polypeptide chain gets released by release factors and the ribosome detaches from the mRNA and tRNA

form of gene regulation

if the gene is needed the repressor falls off

if a gene is on, you make the protein, if its off, you dont