Reaction of 3-acetonyl-5-cyano-1,2,4-thiadiazole with phenylhydrazine hydrochlorides: indolization and phenylpyrazolation.

Treatment of 3-acetonyl-5-cyano-1,2,4-thiadiazole (1) with 4-methyl or 4-methoxyphenylhydrazine hydrochloride provided 5-cyano-3-(2,5-dimethylindol-3-yl)-1,2,4-thiadiazole (2) or 5-cyano-3-(5-methoxy-2-methylindol-3-yl)-1,2,4-thiadiazole (3) as the sole product, respectively. In contrast, treatment of 1 with phenylhydrazine hydrochloride resulted in the formation of 5-cyano-3-(2-methylindol-3-yl)-1,2,4-thiadiazole (4) and the unexpected 5-cyano-3-(3,5-dimethyl-1-phenylpyrazol-4-yl)-1,2,4-thiadiazole (5). In a similar manner, when 1 was treated with 4-chlorophenylhydrazine hydrochloride, indolization was suppressed by phenylpyrazolation giving rise to 5-cyano-3-(5-chloro-2-methylindol-3-yl)-1,2,4-thiadiazole (6) and 5-cyano-3-[1-(4-chlorophenyl)-3,5-dimethylpyrazol-4-yl]-1,2,4-thia diazole (7). The reaction mechanism is discussed. Compounds 4, 5 and 6 exhibited weak antimicrobial activity against Helicobacter pylori.

Effect of Tween 80 on formation of the superficial L1 layer of the Mycobacterium avium-Mycobacterium intracellulare complex.

The effects of Tween 80 supplementation of liquid culture medium on the formation of the superficial L1 layer of the Mycobacterium avium-Mycobacterium intracellulare complex (MAC) were examined by serological and scanning electron microscopic experiments. Specific antiserum to the glycopeptidolipids on the L1 layer of M. avium S-139, made in a rabbit, was used for seroagglutination reactions with antigens prepared from strain S-139 grown in medium supplemented with various levels of Tween 80 (0, 0.05, 0.5, 5, and 50 mg/ml). The agglutination titers gradually decreased as the concentration of Tween 80 rose. Scanning electron microscopy showed that the fibrillar materials consisting mainly of glycopeptidolipids on the L1 layer of strain S-139 also disappeared with increases in the concentration of Tween 80. In addition, there was no obvious correlation between (i) the plasmid DNAs and serotypes of MAC and (ii) formation of the L1 layer of MAC. It is therefore concluded that Tween 80 used to supplement liquid culture medium affects formation of the L1 layer, which has been considered to be one of the pathogenic factors of MAC.

Effect of Tween 80 on the growth of Mycobacterium avium complex.

The effect of Tween 80 on the growth of Mycobacterium avium complex (MAC) in liquid culture condition was investigated. Observation of the colony-forming units (CFU) and the morphology of MAC with transmission and scanning electron microscopy showed that Tween 80 at 0.05% in the medium (ca. 0.5 mg/ml) had bacteriostatic action and caused cell elongation. Tween 80 at 0.5% or more in the medium (ca. 5 mg/ml) reduced the quantity of MAC glycolipids and also led to false positive or positive results in biochemical tests for mycobacterial identification using nitrate reductase, urease, or arylsulfatase. To determine whether or not surfactants could reduce the MAC permeability barrier, the minimal inhibitory concentration (MIC) of antituberculosis drugs on MAC was determined in liquid medium with or without several kinds of surfactants including Tween 80. Five surfactants including Tween 80 increased the activity of antituberculosis drugs to MAC. These findings suggest that Tween 80 acts directly on the cell wall of MAC.

Plasmid profiles of Mycobacterium avium complex isolated from swine.

Twenty strains of Mycobacterium avium complex (MAC) isolated from swine and five strains from humans were examined for drug susceptibility and plasmid content. Four strains of swine origin and two strains of human origin harbored plasmid DNAs differing in molecular weights. No relationship between plasmid contents and drug resistance was observed. Southern DNA-DNA hybridization showed that small plasmids from swine MAC strains were homologous to those from human origin at the nucleotide level.

Serologic response to Haemophilus gallinarum in artifically infected and vaccinated chickens.

Serologic responses to Haemophilus gallinarum (HG) were compared in chickens artifically inoculated with living HG and vaccinated with HG bacterin, using tube agglutination (AGG), hemagglutination-inhibition (HI), and agar-gel precipitation (AGP) tests. Infected and vaccinated chickens differed markedly, as did infection routes early after treatment. HI response was delayed and lower in chickens infected intranasally than in vaccinated chickens. Both AGG and AGP responses peaked sooner than HI. AGP response was earlier in infected chickens, but later in vaccinated chickens. A maximum of three lines were observed. All which appeared for vaccinated chickens were similar to those for inoculated ones. A residual line remaining for very long periods for inoculated and vaccinated chickens appeared near the side of well of the HG antigen. The duration of symptoms following HG infection had no correlation with HI, AGG, and AGP titers. From these results, the HI test seems not to be the only serological diagnosis of HG infection in the field.