75 Questions
Which group of antibiotics is related both structurally and clinically to penicillins?
Cephalosporins
What is the sulfur-containing amino acid responsible for the antibiotic action in fresh garlic?
Alliine
Who first synthesized usnic acid between 1933 and 1937?
Curd and Robertson
From which non-microbial source do the essential oils of Juniperus and Pinus spp. derive their antibacterial activity?
Order Coniferae
What is the antifungal agent mentioned in the text that is of fungal origin?
Griseofulvin
Which naturally occurring compound was found in kombucha tea along with lichens?
Usnic acid
Which group of microorganisms are commonly found in soil samples and are known for antibiotic production?
Actinomycetes
Which marine organism is known for producing istamycin A and B, active against both Gram-negative and Gram-positive bacteria?
Streptomycete
Which compound found in Cruciferae is known for treating Malta fever?
Sulfur-containing compounds
What is the effective treatment against Helicobacter pylori, an organism linked to gastric ulcers?
Mastic gum
Which plant has bacteriostatic activity due to its bee glue preparation known as propolis?
Hieracium pilosella
What method involves treating soil samples with chemicals that inhibit interfering bacteria and fungi but not actinomycetes during antibiotic screening?
Using cycloheximide as an antifungal and phenol dilution as an antibacterial agent
What chromatographic tools can improve the detection method for TLC and PC in bioautography?
High performance thin layer chromatography (HPTLC)
What is the main process involved in the industrial production of antibiotics?
Fermentation
Why must the population size of microorganisms be controlled carefully during antibiotic production?
To ensure maximum yield before cell death
What method is preferred to extract and purify antibiotics into a crystalline product?
Solvent extraction
What is typically done to microorganisms used in fermentation to increase antibiotic production?
Genetic modification for higher yield
How is mutation encouraged in microorganisms during antibiotic production?
Through exposure to mutagens like UV radiation
What is the purpose of incubating the agar plates at 25-30C for 3-7 days?
To examine the characteristic colonies of actinomycetes
What is the purpose of transferring the characteristic colonies of actinomycetes onto fresh medium containing pathogenic microorganisms and antibiotics?
To assess the potential usefulness of the antibiotics against different microorganisms
What is the purpose of the bioautography assay mentioned in the text?
To identify whether a chemical substance inhibits bacterial growth
Why is it difficult to detect antibiotics on chromatograms using chemical methods?
Chemical methods cannot accurately detect biological substances like antibiotics
What does the appearance of clear zones on agar medium after incubation indicate during antibiotic detection?
Inhibition of test organism growth by antibiotics
What is the purpose of chromatographing the extract containing newly discovered antibiotics along with a reference in different solvent systems?
To confirm if the extract contains known compounds
Which technique can increase yields by 20-fold or more?
Gene amplification
Which mechanism of action do antibiotics like penicillins and cephalosporins fall under?
Inhibit cell wall synthesis
Which category of antibiotics includes aminoglycosides and tetracyclines?
Inhibitors of protein synthesis
What is a mode of resistance to antibiotics that involves the development of altered enzymes or alternate metabolic pathways in the pathogen?
Development of less sensitive enzymes
Which group of antibiotics is classified as disrupters of cell membranes?
Polymyxins and tyrocidins
What technique, if closely linked with retesting, can significantly impact antibiotic production?
Gene amplification
What is the purpose of using advanced chromatographic tools like HPTLC, OPLC, and PLC in antibiotic detection methods?
To improve the detection sensitivity of antibiotics
How are microorganisms commonly modified during the fermentation process to increase antibiotic yield?
By introducing mutagens like ultraviolet radiation or x-rays
Why is it important to ensure that antibiotics are soluble in organic solvents during the extraction and purification process?
To facilitate the extraction process into a crystalline product
What method is typically used if an antibiotic is not soluble in organic solvents during the extraction process?
Ion exchange
How are mutations encouraged in microorganisms to increase antibiotic production?
By exposing them to ultraviolet radiation or certain chemicals
What is the difference between bactericidal and bacteriostatic antibiotics?
Bactericidal antibiotics kill bacteria while bacteriostatic ones inhibit growth of bacteria.
Who discovered Penicillin?
Alexander Fleming
Which bacterial genus is known for producing streptomycin, chloramphenicol, and erythromycin?
Streptomyces
What was the purpose of Paul Ehrlich's search for a 'magic bullet'?
To develop antibiotics that attack bacterial structures selectively
What is the main difference between synthetic antibacterial agents and natural antibiotics?
Synthetic agents are created in a laboratory, while natural antibiotics come from microorganisms.
What is the purpose of incubating the plates for 3-7 days at 25-30C after streaking the soil sample on agar plates?
To examine the characteristic colonies of actinomycetes
What is the purpose of transferring the characteristic colonies of actinomycetes onto fresh medium containing pathogenic microorganisms and antibiotics?
To check for potential usefulness of the antibiotics against specific bacteria
What is the purpose of the bioautography assay mentioned in the text?
To determine if a substance inhibiting growth is a new antibiotic or a known compound
Why is chemical detection of antibiotics on chromatograms considered difficult according to the text?
Chemical methods are not specific to antibiotics
What does the appearance of clear zones on agar medium after incubation indicate during antibiotic detection?
Inhibition of test organism growth by antibiotics
Which type of marine organism produces istamycin A and B, known for their activity against both Gram-negative and Gram-positive bacteria?
Marine actinobacteria
What is the primary compound found in bee glue (propolis) that gives it bacteriostatic activity?
Flavonoids
Which group of branching procaryotic microorganisms are commonly found in soil samples and contribute to antibiotic production?
Actinobacteria
In antibiotic screening methods, what is the primary purpose of treating the soil sample with chemicals that inhibit interfering bacteria and fungi but not actinomycetes?
To create a selective environment for actinomycetes
Which plant, known for its bacteriostatic activity, is prepared by bees from the pollen of various tree species?
Propolis
What technique involves inserting copies of genes back into a cell to increase antibiotic production?
Gene manipulation
Which mechanism of action involves injury to the plasma membrane in antibiotics?
Inhibit synthesis of essential metabolites
What is the category of antibiotics that includes rifampin and quinolones based on their mode of action?
Inhibitors of nucleic acid synthesis
Which antibiotics classifies as disrupters of cell membranes according to their mode of action?
Polymyxins
What is the method of resistance that involves the development of less sensitive enzymes or alternate metabolic pathways in pathogens?
Development of altered enzymes
What is the purpose of introducing mutagens like ultraviolet radiation or x-rays during antibiotic production?
To encourage mutations that may increase antibiotic production
Why are species of microorganisms often genetically modified during industrial antibiotic production?
To yield maximum amounts of antibiotics
What is the main factor that must be controlled carefully to ensure maximum antibiotic yield before the cells die?
Population size of microorganisms
What is the primary reason for extracting and purifying antibiotics to a crystalline form?
To aid in identification and standardization
How does the use of ion exchange, adsorption, or chemical precipitation impact the purification process of antibiotics?
It removes unwanted impurities from the antibiotic
Why are antibiotics typically grown in large containers with a liquid growth medium during industrial production?
To maintain optimal growth conditions for microorganisms
What role does oxygen concentration play in antibiotic industrial production?
It must be optimal for microorganism growth
What is a critical requirement for maximum antibiotic yield before cells die in industrial production?
Controlled population size of microorganisms
Why must antibiotic extraction and purification aim for a crystalline product?
For better identification and standardization
In what way do advanced chromatographic tools like HPTLC, OPLC, and PLC improve antibiotic detection methods?
By enhancing the detection sensitivity and accuracy
High performance thin layer chromatography (HPTLC) is not mentioned as an advanced chromatographic tool for improving antibiotic detection methods.
False
Antibiotics are primary metabolites produced during industrial fermentation.
False
Mutation is discouraged in microorganisms by introducing mutagens like ultraviolet radiation or x-rays during antibiotic production.
False
Strains used for production microorganisms are always identical to the wild type in industrial antibiotic production.
False
Antibiotics must be soluble in water to be easily extracted and purified to a crystalline product.
False
The population size of microorganisms in industrial antibiotic production does not need to be carefully controlled.
False
Fermentation is the only process involved in the industrial production of antibiotics.
False
Ion exchange, adsorption, or chemical precipitation have no impact on the purification process of antibiotics.
False
Antibiotics like penicillins and cephalosporins disrupt cell membranes according to their mechanism of action.
False
Species of microorganisms are never genetically modified during industrial antibiotic production.
False
This quiz covers the process of streaking varying dilutions of treated soil sample on agar plates to test for the growth of actinomycetes. It includes topics such as incubation conditions, examination of characteristic colonies, and testing for antibiotic activity. Example activities against specific bacteria are also discussed.
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