Antibiotic Production By Streptomyces Flashcards
What is the genus Streptomyces known for?
Comprises more than 800 species of obligately aerobic, Gram-positive, filamentous bacteria
Streptomyces are abundant in soil and produce geosmin compounds that give soil its characteristic aroma.
What do many species of Streptomyces produce?
Antibiotics
Antibiotics are organic metabolites that inhibit or kill other microorganisms.
How do antibiotics typically function?
By interfering with an essential cell process such as the synthesis of protein, nucleic acid, or peptidoglycan.
What was the significance of the discovery and use of antibiotics in modern medicine?
They represented the first known therapeutic agents that selectively targeted pathogenic microorganisms with little or no harmful effect on the patient.
What are narrow-spectrum antibiotics?
Antibiotics that inhibit or kill only limited types of microorganisms.
What are broad-spectrum antibiotics?
Antibiotics that inhibit or kill a wide range of microorganisms, including both Gram-positive and Gram-negative bacteria.
Besides Streptomyces, what are other producers of antibiotics?
Certain types of fungi and a few other bacteria.
What is the first step in testing for antibiotic production by Streptomyces?
Inoculate a Streptomyces isolate as a straight line down the middle of an agar plate.
What is the purpose of testing four strains of bacteria in the antibiotic production experiment?
To see if their growth is inhibited by any compounds produced and released by the Streptomyces cells.
What materials are needed per student for the antibiotic production experiment?
1 TSY agar plate, 1 Czapek’s agar plate.
What characteristic appearance do Streptomyces colonies have?
Small, look like hardened powder, usually white or gray with darkly pigmented centers.
Why might Streptomyces not be found on plates from heated dilutions?
Heated dilutions kill many microorganisms, including Streptomyces.
What is the procedure for isolating a pure culture of Streptomyces?
Use a well-isolated colony as an inoculum and streak it on a Czapek’s agar plate.
What should be done if a loop cannot easily pick a Streptomyces colony?
Pick a chunk of agar containing the organisms or use a loopful of tap water to scrub the surface of the colony.
At what temperature should the plates be incubated?
Room temperature.
