Test 3 Blackboard Review material (topics 6- 7B)

Study Tips: Just some ideas I found useful:

1. Take good notes and review them every night for at least 15 minutes when you get home to see if you understand the material. Ask the professor questions if you find something confusing. She's really good about returning emails.
2. Find a partner to quiz you by asking you the questions below.
3. Take a blank lecture outline and see if you can fill it out by memory
4. Try drawing and labeling the diagrams and processes the professor had us draw from memory
5. Vocabulary, vocabulary, vocabulary:LEARN IT! Most of the key ones can be found on the lecture outline.
6. Try to attend the online review session on Blackboard: Sunday 8-9 pm. I found it very helpful.
7. Make sure to get some sleep the night before and eat a good breakfast.

Good luck! See you in class.

Lecture notes:

Topic 6: weapons of the Invaders July 12th

Topic 7: Immune System Defenses July 16  July 17  July 18 July 19

P.S I'll post the answers to the charts after the review session on Sunday. Dr. Maxwell wants you to try and fill them out yourself first. If you want the answers before then, just email her.

in addition to the above. i try and read the chapters to be covered before class from the textbook and throughout the week take the chapter text online and watch the animations, take the accompany quizzes, listen to the mp3 tutoring sessions, etc provided by the textbook company online.

it covers more then the professor requires but is interesting and useful information if you want to go more in depth on the subject in the future.

http://www.masteringmicrobiology.com/

Weapon	Type  (Chemical or Physical)	Specifically causes (molecular basis)	End result (symptoms or benefit)
ligand	P-molecule
Fimbrae	P-hairlike
Capsule/glycocalyx	P-slimy
Invasins	C-Enzyme
Coagulase	C-Enzyme
Kinase	C-Enzyme
Hyaluronidase	C-Enzyme
Collagenase	C-Enzyme
Leucocidin	C-Enzyme
M protein	C-Enzyme
Hemolysin	C-Enzyme
Digestive enzymes	C-Enzyme
Neurotoxin	C-Exotoxin/protein
Enterotoxin	C-Exotoxin/protein
Cytotoxin	C-Exotoxin/protein
Endotoxin	C-lipid

Weapon	Type  (Chemical or Physical)	Specifically causes (molecular basis)	End result (symptoms or benefit)
ligand	P-molecule
Fimbrae	P-hairlike
Capsule/glycocalyx	P-slimy
Invasins	C-Enzyme
Coagulase	C-Enzyme
Kinase	C-Enzyme
Hyaluronidase	C-Enzyme
Collagenase	C-Enzyme
Leucocidin	C-Enzyme
M protein	C-Enzyme
Hemolysin	C-Enzyme
Digestive enzymes	C-Enzyme
Neurotoxin	C-Exotoxin/protein
Enterotoxin	C-Exotoxin/protein
Cytotoxin	C-Exotoxin/protein
Endotoxin	C-lipid

WEAPONS OF THE INVADERS

Review - Key

For the following, read the scenario carefully, then answer each question pertaining to it.

1.       In the fall of 1863, a young confederate soldier is shot in the leg.  The ball goes straight through the calf, and he is able to staunch the flow of blood and keep up with his regiment when the battle is over and the troop moves on.  Two days later, however, the wound is showing signs of being infected.

• What chemical weapon would a bacterium use to cause the pus oozing from the wound?

Leucocidin – pus is mainly dead white blood cells

What chemical weapon would allow the pathogen to spread through tissues of his calf up into his thigh?

Hyaluronidase – it digests the cell cement between adjacent cells. Collagenase may also be present and work in conjunction with this enzyme

• What chemical weapon would allow the pathogen to enter the bloodstream and spread rapidly throughout his body?

(Strepto)kinase – dissolves clots to allow entry into bloodstream from local infected areas of leg

• What chemical weapon might allow a microaerophilic pathogen to adjust the body’s tissues to favor its reproduction?

Hemolysin – ruptures red blood cells to prevent the arrival of O2 and removal of CO2 in the tissues

2.       Aubrey is a teacher at an elementary school.  She is worried that the children that she works with might get her sick by sneezing into her face, and giving her the meningitis that has been occurring recently.

·         If Aubrey inhales bacteria, what hair-like structure might allow the pathogens to cling to her respiratory mucosa?

Fimbrae

·         What mucoid layer might allow the pathogens to cling to her mucosa?

Capsules or glycocalyx or slime layer

·         If the pathogen has neither of the above structures, what molecule on the surface of the bacterial cell might bind to receptor molecules of her respiratory epithelial cells?

ligands

3.       James has been hospitalized for a nasty pneumonia that did not respond to normal antibiotics, requiring him to get stronger IV antibiotics.  His symptoms of coughing and chest tightness began to subside after 24 hours of these drugs, but at 48 hours he suddenly developed a very high fever, drop in blood pressure, and went into a coma.

·         What type of toxin is likely to have caused his symptoms at 48 hours?  Justify this.

Endotoxins – these are released in large enough amounts when severe infections (lots of bacteria present) are treated, resulting in the death of bacteria and subsequent release of endotoxins.  Symptoms are usually lose of homeostatic functions, resulting in fever, inflammation, drop in blood pressure.

·         Where is this toxin located in/on the bacterial cell?

Within the LPS layer of the cell wall, also known as Lipid A

·         What is the gram reaction of the pathogen causing his pneumonia?

Gram -, since they are the only bacteria with an LPS layer in their walls

·         If James recovers, will he have antibodies against this toxin type?  What are such antibodies called?

James will not make antibodies against this toxin, which are called anti-toxins

·         What type of molecule is this toxin?

The molecule is a lipid, therefore non antigenic, which is why anti-toxins are not produced against them.

4.       The anthrax organism secretes a set of toxins that kill cells in various focal areas such as the brain, intestines, spleen and lungs, leading to necrotic, clotted lesions.

·         If these toxins are secreted, what general type of toxin is this?

exotoxins

·         What type of molecule is this?

protein

·         What specific toxin type causes cell death and necrosis?

cytotoxins

·         The vaccine for anthrax contains actual toxins that have been heated so that they cannot cause damage.  What is the term for a vaccine of this type?

toxoid

5.       Both botulism and tetanus interfere with neuromuscular junctions by binding to the nerve ending itself.  Answer the following questions pertaining to these two potent toxins:

·         What general type of toxin are both of these?

exotoxins

·         What specific type of toxin are both of these, in terms of specific effects seen?

neurotoxins

·         When botulism causes paralysis, why is it limp or flaccid? (What is happening at the molecular level to cause these symptoms?)

The toxin binds to the stimulatory nerve, and prevents the release of neurotransmitter at a synapse.  This means that the muscle does not receive the neurotransmitter, so does not get the signal to contract, therefore remaining in the relaxed state.

·         Would a vaccine made from the tetanus toxin prevent the organism from reproducing in the body?  Why or Why not?

A toxoid allows the body to make anti-toxins and memory cells to attack the actual toxin if it is seen later.  Since the exotoxin is secreted from the bacterial cell, rather than a structural part of the cell, the body does not produce antibodies or memory cells to any portion of the actual bacterium itself.  This means that even though you have been vaccinated against tetanus, you could still be infected by the bacterium, which would reproduce in the body without being recognized.  The vaccine would only allow your body to neutralize the toxin made by these bacteria, eliminating its ability to bind to and affect nerves.

 

FIRST AND SECOND LINES OF DEFENSE

(CASE STUDIES)

For the following, read the scenario carefully, then answer each question pertaining to it. This review is not all inclusive, but should guide you as to the types of information you should be familiar with.

1-The tuberculosis organism is well known for its ability to survive within macrophages of the lungs.
-How would the organism get inside the macrophages?
phagocytosis
-What is the name of the vessicle in which the bacteria would reside in the macrophage?
phagolysosome
-What specific chemicals must the organism be resistant to in order to surive in this location?
lysozyme, acids, digestive enzymes
-What nonspecific defense mechanisms must the bacterium have survived (or avoided) in order to get to the alveolar macrophages?

nasal turbines, hairs, mucus of nose, sneezing reflex, coughing reflex, mucociliary escalator

2-It has been shown that alcohol consumption slows the action of cilia within the body.
-Why would this evidence support the fact that alcholics have more respiratory infections than normal?
mucociliary escalator would not move particuate material, including bacteria, out of the respiratory passageways as effectively as in a healthy person.

3-Emily is talking to Leslie when Leslie unexpectedly sneezes in Emily's face. Emily is immediately concerned that she might get conjunctivitis (an infection of the covering of the eye), but Leslie tells her to chill, chances are low that she will become infected due to the defenses of her eyes.
-What are the non-specific mechanical defenses that could protect Emily?
blinking, flushing action of tears, hairs of eyelashes sweeping air...
-What are the non-specific chemical defenses that could protect Emily?
salt in tears, lysozyme in tears
-What is the specific defense molecule which could protect Emily?
IgA, secretory antibody

4-Athletes often get "athlete's foot", as do people who wear vinyl or plastic shoes or cowboy boots.
-What do these two groups have in common that makes them more vulnerable to foot infection?
Feet remain warm and moist more often, which makes foot area more hospitable to pathogens
-What are some suggestions you might give them to decrease their changes of infection?
Use absorbent powder in shoes, change shoes to more breathable canvas or sandals, take off shoes when arrive home, alternate shoes to allow drying between days.

5- Monishia spills some Staph. aureus culture on her arm. She disinfects the spill, and doesn't worry about the incident further, because she is confident in the ability of her skin to protect her from infection.
-What are all of the chemical and structural defenses on the skin of her arm?
thick layers, sloughing of layers, toughening of skin (cornification with keratin), salt on skin, dry skin, flora of skin
-What four signs of inflammation will she be on the lookout for on her skin?
rubor (redness), calor (heat), dolor (pain), tumor (swelling)

6-Alex has been exposed to the Hepatitis A virus from food at a restaurant. He is a healthy young man, so several non-specific defense mechanisms combine to limit his infection.
-What defenses of the stomach may destroy the virus before it gets into his bloodstream?
acids, flushing action
-What white blood cell will seek and destroy his own viral infected cells?
natural killers, using perforin
-His infected liver cells will release what chemical to help neighboring cells resist infection by the virus?
interferon

 

Level 1 Defenses Comparison

	Normal flora	Tough/thick Cornified	Hair	Salt	Acid	Lysozyme	Flushing	Digestive Enzymes	Ciliary escalator
Skin (epithelium, endothelium)
Respiratory tract
Eyes
Mouth
Urinary Tract (+ male genital tract)
Female Genital tract
Digestive tract

Level 2 Defenses of the body

Process	Cells	Secretions/chemicals	Action / Type of pathogen affected
Phagocytosis
Inflammation
Complement Activation
	Natural killers
		interferon

Level 3 Defenses of the body

Process	Cells involved	Activated by?	What leaves lymph node?	Action / Effect
Cell-Mediated
Humoral				1- 2- 3- 4-    a)    b)    c) 5-

Size comparison of antigens/pathogens: Tell what response would be effective against each.

	Tiny (too small to phagocytize)	Small	Large (too big to phagocytize)
Examples
Cell mediated
Humoral (specific)