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Questions and Answers
What is the common name of the group of branching procaryotic microorganisms that are rich sources of antibiotics?
What is the common name of the group of branching procaryotic microorganisms that are rich sources of antibiotics?
- Cephalosporium
- Cruciferae
- Actinomycetes (correct)
- Dicotyledons
What is the main function of antibiotics?
What is the main function of antibiotics?
- To boost the immune system
- To stimulate the growth of microorganisms
- To suppress the growth of other microorganisms and destroy them (correct)
- To enhance the growth of fungi
What is the purpose of adding cycloheximide to the soil sample in the screening process for antibiotics?
What is the purpose of adding cycloheximide to the soil sample in the screening process for antibiotics?
- To inhibit the growth of bacteria
- To inhibit the growth of interfering fungi (correct)
- To promote the growth of actinomycetes
- To inhibit the growth of actinomycetes
What is the difference between bactericidal and bacteriostatic antibiotics?
What is the difference between bactericidal and bacteriostatic antibiotics?
Who discovered penicillin in 1929?
Who discovered penicillin in 1929?
What is the purpose of adding a 1:40 dilution of phenol to the soil sample in the screening process for antibiotics?
What is the purpose of adding a 1:40 dilution of phenol to the soil sample in the screening process for antibiotics?
What is the temperature range for incubating the agar plates during the screening process for antibiotics?
What is the temperature range for incubating the agar plates during the screening process for antibiotics?
What is the genus of bacteria that is particularly noteworthy for producing antibiotics?
What is the genus of bacteria that is particularly noteworthy for producing antibiotics?
How long are the agar plates incubated during the screening process for antibiotics?
How long are the agar plates incubated during the screening process for antibiotics?
What is the source of antibiotics such as streptomycin and chloramphenicol?
What is the source of antibiotics such as streptomycin and chloramphenicol?
What is the origin of cephalosporins?
What is the origin of cephalosporins?
What is the purpose of transferring characteristic colonies of actinomycetes onto fresh medium containing pathogenic microorganisms?
What is the purpose of transferring characteristic colonies of actinomycetes onto fresh medium containing pathogenic microorganisms?
What is the purpose of using varying dilutions of the treated soil sample during the screening process for antibiotics?
What is the purpose of using varying dilutions of the treated soil sample during the screening process for antibiotics?
What is the property of some cephalosporins that allows them to be administered orally?
What is the property of some cephalosporins that allows them to be administered orally?
What is the purpose of using agar plates containing medium that supports the growth of actinomycetes during the screening process for antibiotics?
What is the purpose of using agar plates containing medium that supports the growth of actinomycetes during the screening process for antibiotics?
What is the antibacterial compound found in fresh garlic?
What is the antibacterial compound found in fresh garlic?
What is the purpose of bioautography assay in antibiotic discovery?
What is the purpose of bioautography assay in antibiotic discovery?
Which of the following is NOT a type of chromatography used in bioautography?
Which of the following is NOT a type of chromatography used in bioautography?
What is the role of the agar medium in bioautography?
What is the role of the agar medium in bioautography?
Why are antibiotics produced industrially through fermentation?
Why are antibiotics produced industrially through fermentation?
What is the purpose of controlling the population size in fermentation?
What is the purpose of controlling the population size in fermentation?
What is the characteristic of antibiotics that requires careful control of population size in fermentation?
What is the characteristic of antibiotics that requires careful control of population size in fermentation?
What is the purpose of using different solvent systems in bioautography?
What is the purpose of using different solvent systems in bioautography?
What is the advantage of using advanced chromatographic tools in bioautography?
What is the advantage of using advanced chromatographic tools in bioautography?
Study Notes
Antibiotics
- Substances produced by microorganisms (bacteria, fungi, actinomycetes) to suppress the growth of other microorganisms and destroy them.
- Include synthetic antibacterial agents: sulfonamides and quinolones.
Types of Antibiotics
- Bactericidal: kill bacteria.
- Bacteriostatic: inhibit growth of susceptible bacteria, leading to eventual death.
History of Antimicrobial Therapy
- 1909: Paul Ehrlich developed salvarsan, used against syphilis.
- 1929: Penicillin discovered by Alexander Fleming.
- 1935: Sulfa drugs discovered.
- 1944: Streptomycin discovered by Waksman from Streptomyces griseus.
Sources of Antibiotics
- Most clinically used antibiotics are of bacterial or fungal origin.
- Streptomyces genus produces antibiotics such as streptomycin, chloramphenicol, chlortetracycline, tetracycline, erythromycin, and neomycin.
- Penicillins, griseofulvin, and cephalosporins are of fungal origin.
Non-Microbial Sources of Antibacterials
- Lichens: usnic acid and vulpinic acid contribute to bacteriostatic and antifungal properties.
- Order Coniferae: Essential oils from Juniperus and Pinus spp. have antibacterial activity.
- Monocotyledons: Fresh garlic's antibiotic action is due to alliine, a sulfur-containing amino acid; ginger has antibacterial properties and aloe vera gel.
Screening for Antibiotics
- Method involves treating soil samples with chemicals that inhibit growth of interfering bacteria and fungi, but not actinomycetes.
- Varying dilutions of treated soil samples are streaked on agar plates containing medium that supports actinomycete growth.
- Incubation for 3-7 days at 25-30°C, then examination for characteristic colonies of actinomycetes.
Detection of Antibiotics
- Bioautography assay: a rapid method for determining whether a chemical substance produced inhibition is a new antibiotic or a known compound.
- Involves chromatographing the extract containing the newly discovered antibiotic along with reference in different solvent systems.
- Detection of antibiotics on chromatogram uses biologic method by placing the developed chromatogram on agar medium seeded with an appropriate test organism.
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Description
This quiz covers examples of compounds found in dicotyledons, including sesquiterpene ketones, sulfur-containing compounds, and others from various plants like hops, myrrh, and compositous plants.
