E2L19: Chemical Methods - Inhibit Protein Synth + Nucleic Acid Synth

Question 1

What do agents that inhibit protein synth do?

Answer 1

affect translation, effects ribosomes, toxic b/c we make proteins

Question 2

Name some groups of agents that inhibit protein synth.

Answer 2

• aminoglycosides, tetracyclines, nitrobenzene, macrolide, linezolid

Question 3

What are aminoglycosides? Examples?

Answer 3

• glycosides common in plants
• add sugar to chemical so it can go into soln
• broad spectrum, but clinically typ for G-
• 2 toxicities: OTO (ears) and Nephro (kidneys), severe infections
• ex: streptomycin, neomycin, gentamycin, capreomycin, kanamycin, amikacin

Question 4

Streptomycin?

Answer 4

• aminoglycoside - inhibit protein synth

- DOC for severe infections of TB (MDR/XDR) and for Black Plague (Yersinia pestis)

Question 5

Neomycin?

Answer 5

• aminoglycoside - inhibit protein synth
• broad spectrum
• in triple ointments
• DON’T USE for LARGE BURNS –> can go systemic and cause HEARING LOSS

Question 6

Gentamycin?

Answer 6

• aminoglycoside - inhibit protein synth
• replacing streptomycin, esp for G- infections (esp. if nosocomial)
• typ w/ ticarcillin
• for Pseudomonas aeruginosa Other infection, typ in combo with ticarcillin

Question 7

Capreomycin, Kanamycin, Amikacin

Answer 7

• aminoglycosides - inhibit protein synth

- MDR or XDR TB

Question 8

Tetracyclines? Example?

Answer 8

• ex: Doxycycline
• -> common for most infections:
• > Substitute for Penicillin for G+
• > Borrelia (Lyme, spirochete)
• > Chlamydia trachomatis UTI (STD, adult form)
• > Mycoplasma pneumo (CAP)
• > Rocky Mountain Spotted Fever (Rickettsia)

Question 9

Nitrobenzene Derivative? Example?

Answer 9

• toxic
• inhibits protein synth
• causes aplastic anemia (prevents bone marrow from making RBC/WBC)
• ex: chloramphenicol - LAST CHOICE
• -> for VRE (vancomycin resistant entereococci)
• -> for typhoid fever (salmonella typhii)
• -> meningitis (haemophilus influ.)

Question 10

Macrolides? Examples?

Answer 10

• ex: Azithromycin (Zithromax)
• -> DOC for many infections:
• > N. gonorrhea in pregnant women allergic to beta-lactam antibiotics (ex: cephalosporins, penicillins, carbetalactams)
• > Chlamydia trach. UTI, Myco. pneumo. (CAP), Bordetella Pertussis, Legionella Pneumophila
• ex: Erythromycin
• -> DOC for:
• > ophthalmia neonatorum + Chlamydia trachomatis + N. gonorrhea in babies
• > Myco. pneumo.
• > Bordetella pertussis
• > Corynebacterium diphtheria

Question 11

Linezolid? Aka?

Answer 11

• inhibits protein synth
• aka Zyvox
• toxic, blocks 1st ternary complex during translation
• DOC for systemic MRSA serious infections

Question 12

What do agents that inhibit nucleic acid synthesis do? Some interfere with RNA synthesis! Some DNA synthesis!

Answer 12

• they’re structural analogues -> fit into DNA and are mutations, organism dies
• toxic to humans, all eukaryotes, prokary, and viral DNA

Question 13

What are some examples of agents that inhibit RNA synthesis?

Answer 13

rifampin, ethambutol

Question 14

Rifampin?

Answer 14

• inhibits RNA synthesis
• DOC for TB
• blocks RNA polymerase

Question 15

Ethambutol?

Answer 15

• inhibits RNA synthesis
• DOC for TB
• might interfere w/ RNA polymerase?
• definitely blocks mycolic acid in TB tho

Question 16

Name some examples that interfere w/ DNA synth.

Answer 16

acyclovir, AZT (azidothymidine), griseofulvin, fluoroquinolones (ciprofloxacin, moxifloxacin), metronidazole (aka Flagyl), mebendazole

Question 17

Acyclovir?

Answer 17

• inhibits DNA synth
• purine analogue (adenine, guanine)
• DOC for Herpes (cold sores, genital)

Question 18

AZT? aka?

Answer 18

• aka azidothymidine
• inhibits DNA synth
• pyrimidine analogue for thymine
• in past, used for long term AIDS patients
• -> formally #1 DOC for AIDS
• now used to prevent pregnant mom passing AIDS to baby

Question 19

Griseofulvin?

Answer 19

• inhibits DNA synth
• from penicillium
• antifungal
• affects microtubules, blocks mitosis, toxic!!!
• DOC for severe athlete’s foot (trichophyton sp) oral
• -> trichophyton can get into hair and very difficult to get rid of
• blocks mitosis (cell division) by affecting cytoskeleton

Question 20

Fluoroquinolones? Examples?

Answer 20

• ex: ciprofloxacin and moxifloxacin
• lots of side effects
• inhibits DNA synth
• blocks DNA gyrase from coiling DNA
• -> CIPROFLOXACIN DOC for Pseudo. aeruginosa UTIs and Bacillus anthracis

Question 21

Metronidazole? aka?

Answer 21

• aka Flagyl
• inhibits DNA synth
• gets reduced in anaerobic conditions, acts as structural analogue in DNA –> for anaerobic infections
• DOC for: amoebic dysentery, trichomonas vaginalis, antibiotic colitis (get after use of broad spectrum antibiotics like ampicillin, caused by Clostridium difficile)

Question 22

Mebendazole?

Answer 22

• inhibits DNA synth
• binds to microtubules, affects ATP synthase
• antihelminthic (worm infections)

Question 23

All of the following antibiotics inhibit protein synth except:

a) chloramphenicol
b) tetracycline
c) erythromycin
d) streptomycin
e) rifampin

Answer 23

e) rifampin

rifampin inhibits nucleic acid synth, blocks RNA synthesis

Question 24

Which of the following descriptions of antiviral chemotherapeutic agents are mismatched?

a) acyclovir - herpes simplex virus
b) ribavirin - respiratory syncytial virus (RSV)
c) azidothymidine - AIDS
d) interferon - produced naturally by infected animals
e) none of these

Answer 24

e) none

iunno what ribavirin or interferon are, but w/e

Question 25

Uses of antiparasitic drugs includes all of the following except?

a) mebendazole - malaria
b) quinine - malaria
c) chloroquine - malaria
d) metronidazole - amebicide
e) metronidazole - trichomonas

Answer 25

a) mebendazole - malaria

mebendazole is an antihelminth