1) What is the role and sepcific activity of the cyclohexamide in the Actinomyces Isolation Agar? 2) What was the purpose of air-drying the soils treatments prior to the initial serial dilution? Solution Cycloheximide is the eukaryotic protein synthesis inhibitor produced by the bacterium streptomyces griseus. It interferes with the translocation step in the protein synthesis(movement of two tRNA molecules and an mRNA molecule in relation to ribosome.) thus blocking translational elongation. Significant toxic side effects of cycloheximide include Teratogenic defects ( birth defects ), Reproductive effects ( sperm defects ) and DNA damage. Uses of cycloheximide :It is used as an experimental tool to detect the half life of a protein. It is used as Rodenticide and Pesticide Actinomycetes Isolation agar is used for the isolation and propagation of actinomycetes from soil and water. Cycloheximide in a concentration of 50 micro gram per ml is used . It acts as a fungicide which acts aginst the growth of the fungi in the culture of actinomycetes in agar medium. Prior to the initial serial dilution, soil is air dried which helps in the isolation of rare actinomycetes species.later the soil is treated with phenol and grown on agar medium . the medium is treated with cycloheximide to act as fungicide ..