| Product |
Screen |
| Extracellular enzymes |
|
Amylase |
Starch in agar; detected by clear zones on iodine staining |
Proteases |
Protein suspended in agar; detected by cleared zones |
Lipases |
Target lipid emulsified in agar; detected by cleared zones |
Urease |
PH indicator in urea agar (indicator, phenol red) |
| Enzyme inhibitors |
Enzyme-containing agar; the procedure for enzyme detection suitably modified |
| Antimicrobials |
l. Primary screen is based on a broad range of specific resistant or hypersensitive microorganisms, e.g., Penicillium avellaneum and recombination-deficient strains of Bacillus subtilis and E. coli for antitumour agents; Acholeplasma laidlawii for polyether antibiotics, etc. |
| 2. Secondary screen uses more specialized media and conditions |
| Antifungals |
Chitin synthase inhibition (chitin, i.e., (1 à 4)-β-homopolymer of N-acetylglucosamine, is a major constituent of fungal cell wall) |
| Antiviral agent |
Agar-diffusion tissue culture method for in vitro and in vivo screens using complex fermentation broths; antiviral agents pyrazomycin and mycophenolic acid identified in this manner |
| Antitumour agents |
1. Prescreen uses microorganisms known to be sensitive to antitumour agents, e.g., P. avellaneum, mutants of B. subtilis, E. coli etc., mycoplasma Acholeplasma laidlawii, etc. |
| 2. Initial screens are based on in vivo animal testing which is complex and time-consuming. |
