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BIO234 Lecture 10-25-20056


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the 5 physical methods of microbial death/or slow growth?
1) Heat
2) Cold
3) Filtration
4) Drying
5) Radiation
3 different ways heat can be used in microbial death?
1) Moist - autoclave; kills everything (sterilization)
2) Dry - Flaming; less effecient
3) Pasteurization - heat up to 63C for about 30 min; kills off most human pathogens
process of cold meathod is also called?
explain filtration, as in a short essay?
passage of fluid/gas through a sieve designed to trap particles (cells or viruses) and separtate them from fluid/gas.
when would filtration be a possible method of removal of microbes?
used to sterilize such heat senstive materials as opthalmic solutions, antibiotics, cvaccines, liquid vitamins, enzymes, and culture media
why does drying work as a method of physically destroying microbes?
removal of water inhibits cellular metabolism because enzymes are fully functional only in aqueous environments
what are the two types of Radiation that can be used as a physical method of microbial death?
1) Ionizing
2) Non-Ionizing
what is the difference of two types of radiation?
Ionizing - damages DNA (in food) by use of X-rays
Non-Ionizing - damages DNA and Proteins by use of UV radiation.
explain how Ionizing radiation works?
x-ray wavelengths stike molecules, they have a suffiecint energy to eject electrons from atoms, creating ions
explain how Non-Ionizing radiation works?
UV radiation contains enough energy to excite electrons and cause them to make a new covalent bond - affect 3D struture of proteins and nucleic acids
what are the 7 types of chemical Methods of microbial death?
1) Phenols/Biguanides
2) Halogens
3) Alcohol
4) Surface agents
5) Quats
6) Aldehydes
7) Peroxides
how do and what are examples of Phenols/Biguanides?
they denature enzymes, and injure plasma membranes
Listeren, surgical Lysol scrubs
how do and what are examples of Halogens?
kill viruses; strong oxidizers - lose e-, also loosing H making molecules not functional anymore.
Betadines, chlorine
how do and what are examples of alchol?
70-95% alcohol to be effecive
destroys lipids, and plasma enzymes
how do and what are examples of surface agents?
Mechanical removal - not as effective as other methods
soaps and etergents
how do and what are examples of Quats?
destroys cell membranes (Gram negative bacteria)
Scope, foaming mouthwash
how do and what are examples of Aldehydes?
denature proteins and nuclic acids
these kill spores
Ethylene oxide, disinfectant and embalming fluid
*cancer causing - not commonly used method
how do and what are examples of Peroxides?
destroy dysulfide bridges; denature proteins by braking up dysolfide bonds
Benzoyl peroxide (acne medicine)
Super Infection
infection caused by the removal of normal microbes so pathogens thrive
they kill off competition
Broad-spectrum antibiotic
an antimicrobial agent which attacks a wide variety of microbes
two antimicrobial work best when used together
Nucleoside analogy
kills viruses
mimics precurses to DNA (will mimic a G,C,T,A)
antimocrobial that is produced by a mold or naturally
senthetically or naturally occuring
5 causes for antibiotic resistance?
1) overuse and misuse of antibiotics
2) use of antibiotics as a precaustion
3) failure of patients to follow tx
4) antibiotics in animal feed
5) world travel
4 ways antimicrobial drugs work?
1) inhibition of cell wall synthesis
2) Interference with cell membrane function
3) Inhibition of protein synthesis
4) Interference with nucleic acid syntheis
how does selective toxicity work?
*focus to kill invader without killing the host
*taking advantage/disadvantage of bacteria and host
what is an example of an inhibitor of cell wall synthesis and how does it work?
Beta-Lactam Ring: stops petidogylcan cross bridges from being formed - effects Gram Positive bacteria (we do not have peptidoglcan)
what enzyme is resistan to Penicillin?
enzyme that breaks down Beta-Lactam ring
2 different antimicrobials used in interfering with cell membrane function?
Polymyxins and Tyrocidins
explain how Polymyxins are used to interfere with cell membrane function?
insert themselve into plasma membrane - punching holes into them causing cell rupture
what are the drawbacks of using Polymyxins and why?
human cells contain cell membranes - can cause liver damage
how is Tyrocidin used, how does it work, and what are the drawbacks to the antimicrobial
topical application to rupture membrans of microbes. Highly toxic and can cause skin infections.
4 medication that inhibit protein synthesis?
1) tetracycline
2) erthyromycine
3) streptomycine
4) chloramphenicol
explain what tetracyline does.
inhibits protein synthesis - blocks docking site of tRNA
explain what erythromycine does.
inhibits protein synthesis - bind to ribosomes physically stops it from moving down RNA
explain what streptomycine does.
inhibits protein synthesis - causes mRNA to be miss read, with wrong protein
explain what chloramphenicol does.
inhibits protein synthesis - stops peptid bonds from being formed - last resort
of the 4 medications that inhibit protein synthesis, which are classified as broad spectrum?
tetracycline and erthyromycine
what medication interferes with nucleic acid synthesis?
what does Rifampin do?
interfers with nucleic acid synthesis -
blocks transcription, mRNA can not be made
what two diseases is Rifampin rx for?
TB and minigities
what is an example of an antivial agent?
what is Acyclovir and what does it do?
antiviral agent -
blocks DNA replication; nucleoside anologe
Acyclovir is rx for ?
Herpes virus
8 key elements that make a virus a virus?
1) oblige intrecellular parisit
2) few or no enzymes for metabolism
3) cannot make protein
4) cannot make ATP
5) must use host machinery to replicate
6) only has either DNA or RNA
7) protein coat surrounds nucleic acid
8) ALL transfer DNA or RNA to other cells
3 viral components
nucleic acid
what 4 things can viral nucleic acid be?
single strand
double strand
capsid is what?
a protein coat that surrounds the nucleic acid
what makes up the viral capsid
what is an envelope when talking about viruses?
portion of membrane system of host cell aquired during viral replication or release - composed of phospholipid bilayer and protein of host cell
3 shapes of viruses
Helical refers to?
capsomers bond together in spiral fasion to form tube around the nucleic acid
Attachment occures with bacteriophage, where/how?
via tail fibers to cell wall
attachment occures with animal virus, where/ how?
attach to plasma membrane
penetration occurs with bacteriophage how?
Injection - capsid doesn't enter
Penetration occurs with animal virus, how?
capsid enters by endocytosis or fusion
uncoating occurs with bacteriophage?
None - it doesn't
Uncoating occurs with animal virus how?
Enzymes remove capsid
Biosynthesis in bacteriophage occurs where?
in cytoplasm
Biosynthesis in animal virus occurs where?
in nucleus (DNA) or cytoplams (RNA)
Chronic infections occurs bacteriophage?
chronic infection occus in animal virus?
Latency, slow viral infection
How does release occurs in bacteriophage?
Hose cell lysed
How does release occur in animal virus?
Enveloped viruses bud, non-enveloped viruses rupture plasma membrane
4 specific things about normal body flora
1) compete for nutrients
2) can affect pH
3) affect amount of O2
4) generate compounds (bactereocidins)
2 kinds of "disease"
non-communicable and communicable
explain non-communicable disease
disease that is not easisily pass to other people
explain Opportunisitic pathogen
an organism that thrives when normal flora die
example Candida albicans (yeast infection)
explain Communicable disease
spread easily
example - TB, Measels, Herpies, flu
3 types of infectious disease
1) acute disease
2) chronic disease
3) latent disease
explain acute disease
disease that develops quicky and runs it course quickly
explain chronic disease
disease which developes more slowly, persist longer period of time
explain latent disease
Herpies, infection followup /c inactive chickenpox
what are the 5 stages of infectious disease
1) Incubation period - no s/s
2) Prodromal phase - vague, general symptoms
3) Invase phase - most severe s/s
4) declice phase - declining s/s
5) convalescence period - no s/s
what stages are the most contagious
2,3,4; prodromal, invasive and decline stages
what is nosocomial infection?
hospital aquired infections
what percent of all pt aquire nosocomial infection?
5- - 15% of all patients
how many pt die each year of nosocomial infections
20,000 people
explain portals of entry for disease
disease has to get into cause damage and evade the immune system
what are "capsules"?
polysaccharide coating on the outside of the cell wall and membrane
how is a capsule different from a spore?
capsules are still living and multiplying; stop phagocyctosis from happening
how is a cell wall a defense for envading?
mycobacterium waxy coating that doesn't get phagocised
what do hemolysins do?
break down red blood cells
difference between alpha hemolysins and beta hemolysins?
Alpha - not a virulent and only break down part of the cell
Beta - completely break down the red blood cells
what do Leukocidin enzymes do?
break down white blood cells
what do coagulases do?
enzymes that clots blood cells, and walls itself off from the immune system
what does Kinase do?
disolves clots and allows the bacteria to get in the blood stream and then goes through out the body
what are bacterial toxins?
bacteria that form toxins ar the ones that make us sick
what is the percent of toxings that damage cell membrane?
40 %
what are the 7 bacterial toxins we studied?
1) exotoxins
2) cytoxins
3) Neurotoxins
4) enterotoxins
5) endotoxins
6) plasmid toxins
7) phage genes
what are specifics of Exotoxins?
going to be release while bacteria cell is living
specificis of Cytoxins?
kill the cells completly - Diphtheria
specifics of Neurotoxins?
interfere with nerve transmissions - Botox
Tetnis in a state of contraction all the time
specifics of Enterotoxins?
are going to affect the lining of the GI tract
specifics of endotoxins?
only released when the bacteria cell is dead - they start causing chills, fever, and shock. ALL are Gram Negative
specifics of Plasmid toxins?
need plasmids to be able to cause an infection
specifics of Phage genes?
carried by the phage to infect. Has toxins in their DNA and is transferred to the bacteria
anything foreign in the body
6 types of non-specific defense
1) physical barriers
2) chemical barriers
3) cellular defenses
4) inflammation
5) fever
6) molecular defenses
what are you first lines of defense.
physical and chemical barriers
what is your third line of defense?
specific immune responses that form antibodies and t-cells
how is skin antimicrobial?
dry - bacteria love wet, and skin sloughs off and bacteria get swept away
how are lysozomes a chemical barrier
able to break down gramnegative cell walls
Sebum - how does it work at a chemical barrier
oil on skin contains an antimicrobial
sweat - how does it work as a chemical barrier
high in salt and it kills bacteria
4 elements to respritory system that act as barriers
1) hair in nose, and ciliated cells in trachea filters
2) mucus - traps anything foreign
3) epiglotis covers airway when you eat adn keeps microbes out of your lungs
4) gastric juices when you swallow mucus it kills it
uro-genital system works as a barrier, how?
urninary tract flushes stuff out. Secretions from the vagina also get rid of bacteria
Pluripotent stem cells?
all white blood cells or all cells come from stem cells
3 types of granulocytes
1) basophiles - release histamines
2) neutrophils - phagocytes
3) eosinophils - phagocytosis involved with parasitic worm infections
difference between agranulocytes and granulocytes?
angranulocytes do not have specs were as granulocytes when they are stained they look like they have specs of sand allover it
example of an agranulocytes is?
Monocytes - immature macrophages
what are Opsonins?
antibody coat that help with adhesive they make sticky
Phagocytosis phases are refered to as?
Seatch and Destroy
what are the 5 phases of phagocytosis?
1) Chemotaxis
2) Adherence
3) Ingestion
4) Digestion
5) Elimination
what does chemotaxis do?
Chemotaxis is when macrophages sense bacteria and go after it
what happens in the adherence phase?
bacteria sticks to the macrophages
what happens int he ingestion phase of phagocytosis?
bacteria is stuck and the macrophage engulfs bacteria phagosome
what happens during the elimination phase?
all the bacteria are released via exocytosis
what happens during th edigestion phase of phagocytosis
chews up bacteria; phagosome fuses to a lysome and becomes a phagolysome.
what does the microbe Chlamydia do?
Chlamydia is a bacteria inside cells stop that phagosome from binding with a lysome
7 steps of inflammation /c bacteria
1) redness
2) pain
3) swelling
4) heat
5) wants to destroy agent of injury
6) wall off agent or injury
7) repair any tissue
what does histoamine do to blood?
increase blood vessels permeability - makes vesssels leaky
what is Kinnis?
increase permeability and vasodilation
help the white blood cells squeeze through gaps in blood vessels
help phagocyte attach to bacteria, also increase blood vessels permeability
how fast is the migration of phagocytes?
they get to the injry within an hour
blood cells getting to injury site and squeezing through capillaries, Monocyte and Neutrophils
what are the 3 elements of a fever?
1) Interleukin-1 - came from macrophage, into blood stream
2) hits Hypothalamus - release protoglandin
3) progoglandins reset interrnal thermostate to increase body temp
pros and cons of fever?
Pros - 1) body makes temp. to inhibit bacterial growth
2) antiviral proteins - temp could intensivfy effects
3) metabolic reason - reactions can speak up repair processes
cons - high temp can damage body over long period of time
to interfer /c viral replications and overall synthesis of virus
Anti-viral proteins
cell will produce interferons - released to act on neighboring cells not yet infected - neighboring cell will synthesis AVP, if cells gets infected, virus will not replicate
Gramma cell is different than Alpha and Beta how?
cell producing AVP does not need to be infected by virus to produce interferon
Complement referse to ? in regards to melecular defenses
20 different proteins from blood plasm which signal cascade of events in the immune system
explain Classical pathway of complement
bacteria bound /c antibitics (opsonization)
c1 proeins will bind to antibody antigen complex
c1 causes c2 & c4 to split
c2a and c4b will cleave c3
c3a & c3b start effects
c3b cleaves c5
c5b,c6,c7,and c8 bind together to form complex
c9 punch hold causes cytolysis
what 2 things does c3a do?
increases blood vessel permeability and chemotactic atraction of phagocytes
what is the main event of c3b
how is alternative pathway different than classic pathway?
alternative pathway outcome the same, but no antibodies were needed to start the process
explain nuclic acid of HIV
single stranded RNA viruses -
sense RNA
what are the cellular targes of HIV
the immune system - specificaly T4 - cd4, macrophages, and leangerhans (epidermis, skin, no blood cells)
what are the 2 strains of HIV
clades1 - HIV most common in US, 15-20% variability of mutations
clades2 - WEstern Arican - longer incubation time,not as pathogenic
routs of tranmission of HIV
body fluid contact - sexual, vaginal oral anul
sharing needles
receive or give blood tranfusion
passage from mother to child

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