A new 1H-pyrazole-3-carboxylic acid 2, along with hydrazono-pyridazinone 3, a by-product, and its derivatives 4-7 were synthesized and the structures confirmed by infrared (IR) and 1 H and 13 C nuclear magnetic resonance (NMR) data. These new compounds were evaluated for their antibacterial activities against Gram-positive and Gram-negative bacteria using the tube dilution method. The minimal inhibitory concentrations (MICs) experiments revealed that most compounds exerted inhibitor effects against Klebsiella pneumonia, Escherichia coli, Bacillus subtilus, and Xanthomonas compestris test microorganisms. Moreover, the results showed that the pyrazolo[3,4-d]pyridazine compounds were the best compounds of the series, exhibiting antibacterial activity against both Gram-positive and Gram-negative bacteria.
The taxonomic positions of soil isolates known as Streptomyces groups A, B and C were clarified. Comparative 16S rDNA sequence studies indicated that representatives of all three taxa formed distinct phyletic lines within the Streptomyces tree though the group A strains were shown to be related to Streptomyces griseus and associated validly described species. The taxonomic integrity of all three groups was highlighted by DNA:DNA relatedness and ribotype data though the group A strains encompassed a higher degree of genetic variation than the group B and C strains. In light of these and earlier phenotypic data it is proposed that Streptomyces groups A, B and C be given species status as Streptomyces sanglieri sp. nov., Streptomyces aureus sp. nov. and Streptomyces laceyi sp. nov., respectively.
Members of three putatively novel Streptomyces species, designated Streptomyces groups A, B and C, were repeatedly isolated from environmental samples taken from four hay meadow plots at Cockle Park Experimental Farm, Northumberland (UK). Representative isolates were found to have properties consistent with their classification in the genus Streptomyces and were recovered in three taxa using different phenotypic criteria, namely morphological and pigmentation properties, rapid enzyme tests, and whole-organism fatty acid, protein electrophoretic and pyrolysis mass-spectrometric data. The isolates were rapidly characterised as three taxonomic groups using pyrolysis mass spectrometry. The three taxa were also distinguished from one another and from validly described species of Streptomyces using rapid enzyme tests based on the fluorophores 7-amino-methylcoumarin and 4-methylumbelliferone, and computer-assisted identification procedures. The results indicate that selective isolation and rapid characterisation of streptomycetes using pyrolysis mass spectrometry provide a practical way of determining the phenotypic species diversity of streptomycetes in natural habitats. The experimental data also indicate that representative sampling of cultivable streptomycetes from soil can best be achieved using a multi-step extraction procedure coupled with the use of selective isolation procedures.
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