By: Azreena (D11A005) & Nur Nabila (D11A027)
description
Transcript of By: Azreena (D11A005) & Nur Nabila (D11A027)
![Page 1: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/1.jpg)
By: Azreena (D11A005) & Nur Nabila (D11A027)
![Page 2: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/2.jpg)
WHAT IS ANTIBIOTICS?
• Also known as antibacterial, the drugs used to treat infections caused by bacteria.
• Antibiotics target microorganisms such as bacteria, fungi and parasites. However, they are not effective against viruses.
• If antibiotics are overused or used incorrectly there is a chance that the bacteria will become resistant .
![Page 3: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/3.jpg)
TRANSCRIPTION
• A process where the genetic information in DNA is transferred to a complementary sequence of RNA nucleotides by DNA-RNA polymerase.
• 3 Antibiotics that will inhibit TRANSCRIPTION process:
A) Actinomycin DB) Rifampin (Rifampicin or Rifamycin)C) Quinolones
![Page 4: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/4.jpg)
A) Actinomycin D• Antibiotics that inhibits transcription by
binding DNA at the transcription initiation complex and preventing elongation by RNA polymerase.
![Page 5: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/5.jpg)
B) Rifampin (Rifampicin or Rifamycin)
• Antibiotics that inhibits protein synthesis by inhibit DNA-RNA polymerase. It does this by binding to the ß subunit of RNA polymerase.
• .
![Page 6: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/6.jpg)
C) Quinolones
• Antibiotics that inhibit the bacterial DNA gyrase or the topoisomerase IV enzyme, thereby inhibiting DNA replication and transcription.
![Page 7: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/7.jpg)
EXAMPLES OF QUINOLONES ANTIBIOTICS:
![Page 8: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/8.jpg)
Mechanism of Action of Antibiotics
![Page 9: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/9.jpg)
Actinomyocin D
• Actinomyocin D inhibits initiation of DNA transcription.
• It does this by binding DNA at the transcription initiation complex and preventing elongation by RNA polymerase.
![Page 10: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/10.jpg)
Transcription initiation complex
![Page 11: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/11.jpg)
Rifampicin• Rifampicin acts directly on
messenger RNA synthesis.
• It inhibits RNA polymerase in bacterial cells by binding to its beta-subunit, thus preventing transcription to RNA and subsequent translation to proteins.
• It inhibits only prokaryotic DNA-primed RNA polymerase, especially those that are Gram-stain-positive .
• Its lipophilic nature makes it a good candidate to treat the meningitis form of tuberculosis, which requires distribution to the central nervous system and penetration through the blood-brain barrier.
![Page 12: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/12.jpg)
RNA Polymerase
![Page 13: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/13.jpg)
Quinolone
• Quinolones inhibit bacterial replication by blocking their DNA replication pathway.
• Quinolones binds to the A-subunit of the DNA gyrase (Topisomerase II) in Gram-negative bacteria and Topoisomerase IV in Gram-positive bacteria.
• This causes the topoisomerase unable to unwind the DNA coiling hence, inhibiting replication and transcription.
![Page 14: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/14.jpg)
![Page 15: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/15.jpg)
TASK 2 : LIST DOWN THE ANTIBIOTICS THAT INHIBIT THE PROCESS OF TRANSLATION & EXPLAIN THE MECHANISM OF ITS ACTION
TOWARDS INHIBITING THE PATHOGEN INVASION
By: Murshida (D11A019) & Fathiyah (D11A006)
![Page 16: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/16.jpg)
Antibiotics :
• A number of antibiotics act by inhibiting translation are :
1) Chloramphenicol
2) Tetracyclines
3) Macrolides (eg : Erythromycin)
![Page 17: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/17.jpg)
CHLORAMPHENICOL
• Antibiotics that inhibits translation by binding to ribosomes and preventing the binding of aminoacylated tRNA to the A site.
• It might also inhibit the peptidyl transferase reaction, preventing the formation of peptide bonds.
Aminoacyl-Trnabound to A site
![Page 18: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/18.jpg)
TETRACYCLINES
• Tetracyclines bind to the 30S subunit of microbial ribosomes.
• They inhibit protein synthesis by blocking the attachment of charged aminoacyl-tRNA to the A site on the ribosome.
![Page 19: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/19.jpg)
MACROLIDES (ERYTHROMYCIN)
• Inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit.
• The binding inhibits the translocation steps of protein synthesis.
![Page 20: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/20.jpg)
Mechanism of Action of Antibiotics
![Page 21: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/21.jpg)
INTRODUCTION
• Many useful antibiotics owe their action to inhibit some steps in complex process of translation
• Their attack always during events occuring on ribosomes,rather than stage of amino acid activation or attachment t particular trna.
• Most have affinity to 70s ribosomes• The most important antibitics with this mode of
action are tetracyclines,chloramphenicol,macrolides and aminoglycosides
![Page 22: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/22.jpg)
Aminoglycosides Mechanism
Interfering with translocation by causing misreading of codons along Mrna
• Aminoglycosides inhibit translation of Mrna by binding to 30s ribosome causes misreading of codons along Mrna
• The misreading of codons causes error in proofreading process of translation leading to improper protein expression
![Page 23: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/23.jpg)
Interfering with translocation of tRNA from A site to P site.Aminoglycosides inhibit translation of Mrna by binding irreversibly to 30s subunit of ribosomes.This will inhibit translocation of Trna from A site to P site of ribosomes, preventing elongation of polypeptide chainLead to incomplete protein expression
![Page 24: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/24.jpg)
Tetracyclines Mechanism• Entry of these agents into
organism is mediated both by passive diffusion and energy-dependent transport protein mechanism to bacterial inner cytoplasmic membrane.
• Tetracyclines binds reversibly to 30s subunit of ribosomes
• This prevent binding of aminoacyl Trna to A site of ribosome.
• The protein synthesise is inhibited.
![Page 25: By: Azreena (D11A005) & Nur Nabila (D11A027)](https://reader035.fdocuments.in/reader035/viewer/2022062410/56816621550346895dd977f4/html5/thumbnails/25.jpg)
Macrolides mechanism• Microlides bind reversibly
to 50S subunit of ribosomes.Some macrolides appear to inhibit elongation of protein by preventing enzyme peptidyltransferase from forming peptide bonds between amino acids.
• There is evidence that some prevent transfer of peptidyl tRNA from A site to Psite,thus prevent elongation of polypeptide chain.