21. Respiratory burst (oxidative burst) Flashcards Preview

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Flashcards in 21. Respiratory burst (oxidative burst) Deck (22):
1

Respirator is AKA, and definition

oxidative burst is the release of ROS from different types of cells

2

Respiratory burst (oxidative burst ) playes important role in

immune response --> rapid release of ROS

3

NADPH oxidase deficiency

chronic granulomatous disease

4

Pyocyanic of P.aeruginosa function

generate ROS to kill competing microbes

5

Lactoferrin is a

protein found in secretory fluids and neutrophils that inhibits microbial growth via iron chelation

6

Patients with chronic granulomatous disease

can utilize H2O2 by ig infenctionnvading organisms and convert it to ROS. High risk at CAT+ species capable of neuralizizing their own H2O2, leaving phagocytes without ROS for fightin

7

Lactoferrin is a

protein found in secretory fluids and neutrophils that inhibits microbial growth via iron chelation

8

NaDPH - role in ROS

it plays role in both creation and neutraliation of ROS

9

Myeloperoxidase - function and appearance

H2O + CL ---> HCLO (myeloperoxidase ) --> destroys bacteria blue green heme-containing pigment that gives sputum its color

10

• Name two cells that utilize NADPH for an oxidative burst.

Neutrophils and macrophages

11

• Why do cells like neutrophils and macrophages have high concentrations of NADPH oxidase?


To aid in the immune response by rapidly releasing reactive oxygen species that kill bacteria

12


• Which form of glutathione must be readily available in the cell to remove reactive oxygen species to prevent cell lysis?


The reduced form (GSH)—reducing equivalents are created in the HMP shunt

13

• What is the end product of the oxygen-dependent respiratory burst that is used to kill bacteria in the phagolysosome?


Bleach (HClO), also known as hypochlorite

14


• A boy with chronic granulomatous disease gets recurrent catalase-positive infections. Why not recurrent catalase-negative infections?


He can utilize H2O2 produced by catalase-negative bacteria into ROIs, but catalase-positive bacteria neutralize their own H2O2

15

• A patient with chronic granulomatous disease has recurrent infections. What enzyme is deficient? Which bacteria are likely responsible?


NADPH oxidase; Staphylococcus aureus and Aspergillus are common catalase-positive bacteria in chronic granulomatous disease

16


• ___ is a protein found in secretory fluids and neutrophils that inhibits microbial growth via iron chelation.


Lactoferrin

17

• P. aeruginosa cultures can kill off competing bacteria with high levels of reactive oxygen species. How does this occur?


It produces pyocyanin, which can generate reactive oxygen species to kill competing microbes

18


• A patient with a bacterial infection coughs up blue-green sputum. What is likely giving the sputum its color? What does this compound do?


Myeloperoxidase; it converts H2O2 into HOCl

19

• A patient with numerous vitamin and mineral deficiencies is unable to regenerate reduced glutathione or break down hydrogen peroxide. Why?


Deficiency of selenium interferes with both glutathione peroxidase (converts H2O2 into H2O) and glutathione reductase (regenerates GSH)

20


• Describe the two reactions needed to convert O2 into H2O2.


O2to superoxide via NADPH oxidase; superoxide to H2O2 via superoxide dismutase

21

• In what part of the phagocyte does the respiratory (oxidative) burst take place?


The phagolysosome

22


• Bacteria resistant to the respiratory burst produce more H2O and O2. Will you see increased or decreased hypochlorite (bleach) levels?


Decreased; these bacteria degrade H2O2 into H2O and O2 via bacterial catalase, thus less H2O2 is available to become hypochlorite