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Agrobacterium tumefaciens C58 grown on acidic medium containing glucose and solidified with bacteriological agar expressed a virB::lacZ fusion. No expression of this fusion was observed on a similar medium which was solidified with purified agarose. The fraction from bacteriological agar which was responsible for vir gene induction was extracted with(More)
Little is known about the effect of the host on the genetic stability of bacterial plant pathogens. Crown gall, a plant disease caused by Agrobacterium tumefaciens, may represent a useful model to study this effect. Indeed, our previous observations on the natural occurrence and origin of nonpathogenic agrobacteria suggest that the host plant might induce(More)
The polymerase chain reaction was used to amplify the spacer region located between the 16S and 23S ribosomal RNA genes of strains of Pseudomonas fluorescens and Pseudomonas putida isolated from peat bog, canola field, or arctic plants. Some of spacer region of four of the P. fluorescens strains examined, strains 64-3, 63-28, QP5, and R17-FP2, was about 515(More)
Agrobacterium tumefaciens C58F is a variant of strain C58 which generates a high proportion of avirulent mutants in the presence of the virulence (vir) gene inducer acetosyringone. These mutants are altered in the Ti plasmid and do not respond to the acetosyringone signal (C. Fortin, E. W. Nester, and P. Dion, J. Bacteriol. 174:5676-5685, 1992). The(More)
Bacteria were isolated from soil and crown gall tumors by selection in minimal medium with an opine, such as succinamopine or mannopine, as the sole carbon source. The isolates were characterized for the pattern of opine utilization and identified. They were classified as mannityl opine or imino diacid utilizers and exhibited specificity of utilization(More)
A PCR-denaturing gradient gel electrophoresis (DGGE) method was used to examine on-farm sources of Clostridium cluster I strains in four dairy farms over 2 years. Conventional microbiological analysis was used in parallel to monitor size of clostridial populations present in various components of the milk production chain (soil, forage, grass silage, maize(More)
Acetosyringone, a phenolic inducer of the virulence (vir) genes of Agrobacterium tumefaciens, inhibited the growth of the nopaline-type strains T37 and C58 incubated under acidic conditions. In the course of a 6-day incubation with acetosyringone, avirulent clones were produced in different proportions by strains T37 and C58 and also by a spontaneous(More)
This study was conducted to determine the capacities of 37 fungi to utilize various crown gall opines as their sole carbon and nitrogen source. One strain of Fusarium solani, two of Cylindrocarpon destructans, and six of Cylindrocarpon heteronema catabolized octopine, mannopine, octopinic acid, succinamopine, or a combination of these opines. One C.(More)
The characteristics of mannopine and mannopinic acid utilization by Agrobacterium tumefaciens B6S3, Arthrobacter sp. strain MBA209, and Pseudomonas putida NA513 were studied. Strain B6S3 utilized the four mannityl opines, mannopine, mannopinic acid, agropine, and agropinic acid. It also utilized several mannityl opine analogs, which were modified in either(More)
Diauxic growth was observed upon incubation of Agrobacterium tumefaciens 15955 on a mixture of succinate and mannopine as the carbon source. Diauxic growth was also observed when either fumarate or L-malate was mixed with mannopine. No diauxie was detectable when A. tumefaciens 15955 was grown on a mixture of mannopine and glucose, fructose, sucrose, or(More)