Conjugative plasmid transfer between Pseudomonas strains within alginate bead microcosms: Effect of the internal gel structure

Because microorganisms frequently live in an immobilized state in natural habitats, a cell‐confined system was used to study bacterial conjugation. Two Pseudomonas putida strains were introduced together within calcium alginate gels. Different alginate beads were designed by varying the polysacchari...

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Bibliographic Details
Published in:Biotechnology and bioengineering 1999-10, Vol.65 (1), p.34-43
Main Authors: Mater, Denis D.G., Saucedo, José E. Nava, Truffaut, Nicole, Barbotin, Jean-Noël, Thomas, Daniel
Format: Article
Language:English
Subjects:
Algae
alginate
alginate beads
Alginates
Bacteria
Bacteriology
Biological and medical sciences
Biotechnology
cell confinement
Conjugation, Genetic
conjugative transfer
continuous cultures
Ecosystem
Fundamental and applied biological sciences. Psychology
Gelation
Gels
Gene transfer
Genetic Engineering
Genetics
Glucuronic Acid
Growth kinetics
Hexuronic Acids
Kinetics
Microbiology
microcosms
Microscopic examination
Microscopy, Electron, Scanning
Plasmids - genetics
Polysaccharides
Pseudomonas
Pseudomonas putida
Pseudomonas putida - genetics
Pseudomonas putida - growth & development
Solutions
Structure (composition)
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Summary:Because microorganisms frequently live in an immobilized state in natural habitats, a cell‐confined system was used to study bacterial conjugation. Two Pseudomonas putida strains were introduced together within calcium alginate gels. Different alginate beads were designed by varying the polysaccharide and the gelation solution concentrations. Microscopic examinations showed that 2% gels were quite homogeneous, but that 1.5% and 1% gels were rather heterogeneous. In these two last cases, shaft‐shaped macrostructures were pres‐ ent. They were colonized during the culture by great densities of highly motile bacteria. Gene transfers due to conjugation were investigated in such alginate gel bead microcosms, in batch and continuous cultures. High‐initial transfer frequencies were detected whatever the gel, but no conjugation events seemed to occur with further growth in the beads. Transfer frequency values were roughly similar in the different tested systems. Alginate gels used as artificial microcosms may be valuable to study the effect of cell microenvironment on genetic transfers in complex systems. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 65: 34–43, 1999.
ISSN:0006-3592
1097-0290
DOI:10.1002/(SICI)1097-0290(19991005)65:1<34::AID-BIT5>3.0.CO;2-Z