Transtorine (1), a new quinoline alkaloid, isolated from the aerial part of Ephedra transitoria by column chromatography, was identified as 4-quinolone-2-carboxylic acid. The structure was determined by spectroscopic methods. Transtorine exhibited growth inhibitory activity against the common bacteria, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

Pure pyocyanin was prepared from 120 strains of Pseudomonas aeruginosa isolated from different clinical specimens. The modified method used increased the purification 425-fold. The spectra of pyocyanin of all strains were found to be identical with a single major peak at 363 nm. The only difference between these spectra appeared to be the level value absorbance. Strains recovered from different clinical specimens differ in their ability for pigment production. The strains isolated from urine produced higher amounts of pyocyanin than other isolates.

Five types of pyocins were found in Pseudomonas aeruginosa strain 112. Production of these types was induced by UV irradiation. The pyocin activity was found to be resistant to trypsin treatment. Their molar mass was found to be 282, 251, 112, 89.1 and 54.9 kg/mol, respectively. The pyocins obtained were different from any known type (such as R, S, F) in their chemical and physical properties.

Fifty-six selected strains of Pseudomonas aeruginosa belonging to 8 different pyocin types (H, I, 15, 6, PTI-1, PTI-2, PTI-3, PTI-4) were treated with subinhibitory concentrations (MIC/2) of either gentamicin or carbenicillin. Both treatments induced changes in pyocin patterns for all types but at different levels. The percentage of strains that retained their pyocin pattern were more or less equal in both treatments. In treated and untreated producers, the growth inhibition ability for 5 different strains of Enterobacteriaceae (Escherichia coli K12, E. coli EB, Proteus vulgaris, Salmonella typhi, Shigella flexneri) was also investigated. In all pyocin patterns the number of producers that inhibit the growth of these strains was lower after treatment with gentamicin or with carbenicillin, a smaller decrease was detected in the latter treatment. It appeared that the subinhibitory concentrations of these antibiotics are capable of protecting the Enterobacteriaceae strains from the action of the pyocins.

Three types of pyocins were found in Pseudomonas aeruginosa strain 986 and named pyocin type P25, P50, and P70. Production of these types was inducible by UV irradiation. Their molar mass was estimated. The pyocins obtained were different from the known pyocins R, S, and F in their chemical and physical properties. No immunological cross reaction was observed among these pyocins.