A phenazine antibiotic (mp, 243 to 244°C), isolated in a yield of 134 ,ug/ml from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132), was indistinguishable in all of its measured physicochemical (melting point, UV and infrared spectra, and gas chromatography-mass spectrometry data) and biological properties from synthetic phenazine-1-carboxylic acid. Weller and Cook (10) reported that the wheat root disease take-all, which is caused by Gaeumannomyces graminis var.tritici, can be suppressed by inoculating wheat seeds with Pseudomonas fluorescens 2-79 (NRRL B-15132). Gurusiddaiah et al. (6) characterized an antibiotic (mp, 242°C) produced by this culture and considered to be significant in this suppressive activity as having an unusual phenazine-1-carboxylic acid dimer structure. However, the physicochemical properties (UV and infrared [IR] spectra and the melting point) of this compound are similar to those of the phenazine-1-carboxylic acid (mp, 238 to 241°C), isolated from P. aeruginosa by Chang and Blackwood (4), and also to the properties of a material (mp, 243 to 244°C) isolated from P. fluorescens 2-79 in our laboratory. These similarities warranted a critical assessment of the data and a direct comparison with synthetic phenazine-1-carboxylic acid. MATERIALS AND METHODSOrganisms. Bacillus cereus, Escherichia coli HB101, and fluorescent pseudomonad strains A37, 2-79, K2-79, and PGPR were routinely maintained on tryptic soy agar (8) or nutrient agar (Difco Laboratories). For long-term storage, bacteria were kept in 40% glycerol at -12°C. The fungi G. graminis var. tritici 500 and Rhizoctonia solani Rh2l were maintained on half-strength PDA medium (potato-dextrose agar powder [Oxoid Ltd.] Antibiosis bioassays. The PDA medium was adjusted by the addition of a suitable pH buffer (20 mM phosphate, 20 mM citrate) instead of water. Bacteria were mixed in 5 ml of molten 2% agar containing 0.1% (wt/vol) peptone and poured over the PDA medium. Portions of the 1.5 mM phenazine-1-carboxylic acid in ethanol were evaporated on sterile paper disks (11-mm diameter) and applied to the agar. Fungi were centrally inoculated onto buffered PDA plates with 3-mm agar plugs obtained from the outer perimeter of actively growing mycelia, and the paper disks treated with phenazine-1-carboxylic acid were applied 2 to 3 days later.Sources. P. fluorescens 2-79 (10) was kindly supplied by

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The reduction of 1-(furan-2'-yl)nonan-1-one with lithium and ammonia in the presence of alcohols gave 1-(2',3'-dihydrofuran-2'-yl)nonan-1-one as the major product or a mixture of 1-(tetrahydrofuran-2'-yl)nonan-1-one and tridecane-1,5-diol depending on the conditions. 1-(Furan-2'-y1)nonyl acetate, 2-(1'-methoxynonyl)furan, 1-(furan-2'-yl)nonan-1-ol, 2-(1',1'-ethylenedioxynonyl)furan and 2-(pent-1'-eny')furan have also been reduced both in the presence and absence of an alcohol.