RESUMO
The influences of medium type, inoculum density, and a cold incubation on antimicrobial assay sensitivity were tested. The largest and most distinct zones were produced using nutrient agar and the 1/10 4 inoculum density for Staphylococcus aureus and Proteus mirabilis but a 1/10 12 inoculum density for Pseudomonas aeruginosa and Escherichia coli . The greatest number of zones were detected without cold incubation. Using this method, eight plants from Belize were screened for antibacterial activity. Six plants showed activity against the four organisms tested. Both inoculum density and medium type played important roles in assay sensitivity; however, inoculum density was of more practical significance.
RESUMO
Pyrolysis gas chromatography coupled with infrared identification of eluted peaks confirms that paraquat is pyrolyzed into chloromethane and 4,4'-dipyridyl at smoking temperatures and above. This reaction occurs at 610 degrees C to completion in small amounts in an inert atmosphere. The toxicity of 4,4'-dipyridyl remains to be determined. Pyrolysis of contaminated marijuana also produces the same two products, although detection at low limits is difficult with this procedure.