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B Digat

Publications and source records attributed to B Digat.

4 recordsLinked to original sources
PubMed1987

Population Heterogeneity of Agrobacterium tumefaciens in Galls of Populus L. from a Single Nursery.

This study focused on the natural crown gall infections occurring in a Leuce poplar nursery. Soil effects on crown gall frequency were detected, indicating that contamination was due to a resident Agrobacterium tumefaciens population, which was present before seedling plantation. The crown gall frequency on poplar progenies varied from 3 to 67%, indicating the feasibility of improvement in crown gall resistance. Of 129 tumor isolates, 128 were pathogenic. These isolates were of biotype 1 or 2. Biochemical, serological, and antibiotic resistance typing results concurred, indicating the presence of four biotype 1 and two biotype 2 resident subpopulations. No significant change was noticed in the relative proportions of subpopulations from one year to another. Pathogenic subpopulations both in vitro and in planta were susceptible to Kerr K84 (P. B. New and A. Kerr, J. Appl. Bacteriol. 90:172-179, 1972). In addition, no serological cross-reactions were found to occur between K84 and the pathogenic subpopulations.

Journal Article↗
PubMedDate not supplied

Microencapsulation of rhizobacteria by spray-drying: formulation and survival studies.

This research deals with the microencapsulation of the bacteria Pseudomonas fluorescens-putida, using the spray-drying technique. These bacteria act as a plant growth stimulator and the microparticles are subsequently included in the seed coating or pelleting material. The objective was to maintain living encapsulated bacteria for a minimum of 5-6 months. Three polymers were tested: a methacrylic copolymer from the Eudragit range, an ethylcellulose and a modified starch. A silica additive to the spraying food was also examined. The granulometric distribution and the morphology of the microparticles were studied and the residual moisture was measured after each bacteria survival control test. The best results were obtained with the methacrylic copolymer Eudragit, particularly for microparticles collected in the cone of the spray-drying chamber. The mean diameter of the microspheres was 44.6 microns, 85% of these particles having a size between 6.2 and 84.4 microns. The bacterial survival time of a particular strain incorporated in these microparticles, strain M3.1, was one year. A relationship was found between the bacterial survival and the microspheres' residual moisture, the best survival of the stored bacteria being observed when the residual moisture was around 25%.

Acrylic Resins↗