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Conjugative plasmid transfer between Pseudomonas strains within alginate bead microcosms: Effect of the internal gel structure
Author(s) -
Mater Denis D.G.,
Saucedo José E. Nava,
Truffaut Nicole,
Barbotin JeanNoël,
Thomas Daniel
Publication year - 1999
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19991005)65:1<34::aid-bit5>3.0.co;2-z
Subject(s) - microcosm , bead , pseudomonas putida , calcium alginate , polysaccharide , homogeneous , chemistry , microorganism , bacteria , pseudomonadaceae , pseudomonadales , gene transfer , bioreactor , sodium alginate , chemical engineering , biophysics , microbiology and biotechnology , chromatography , pseudomonas , biology , biochemistry , materials science , calcium , organic chemistry , environmental chemistry , gene , sodium , physics , genetics , engineering , composite material , thermodynamics
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.