scholarly journals Natural Electrotransformation of Lightning-Competent Pseudomonas sp. Strain N3 in Artificial Soil Microcosms

2006 ◽  
Vol 72 (4) ◽  
pp. 2385-2389 ◽  
Author(s):  
Hélène Cérémonie ◽  
François Buret ◽  
Pascal Simonet ◽  
Timothy M. Vogel
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Residence Time ◽  
Lightning Strike ◽  
Pseudomonas Sp ◽  
Electrical Field ◽  
Soil Microcosms ◽  
Electrical Fields ◽  
Cell Lysate ◽  
Electrical Field Gradient

ABSTRACT The lightning-competent Pseudomonas sp. strain N3, recently isolated from soil, has been used to study the extent of natural electrotransformation (NET) or lightning transformation as a horizontal gene transfer mechanism in soil. The variation of electrical fields applied to the soil with a laboratory-scale lightning system provides an estimate of the volume of soil affected by NET. Based on the range of the electric field that induces NET of Pseudomonas strain N3, the volume of soil, where NET could occur, ranges from 2 to 950 m3 per lightning strike. The influence of DNA parameters (amount, size, and purity) and DNA soil residence time were also investigated. NET frequencies (electrotransformants/recipient cells) ranged from 10−8 for cell lysate after 1 day of residence in soil to 4 × 10−7 with a purified plasmid added immediately before the lightning. The electrical field gradient (in kilovolts per cm) also played a role as NET frequencies ranging from 1 × 10−5 at 2.3 kV/cm to 1.7 × 10−4 at 6.5 kV/cm.

scholarly journals Laboratory-Scale Evidence for Lightning-Mediated Gene Transfer in Soil

2001 ◽  
Vol 67 (8) ◽  
pp. 3440-3444 ◽  
Author(s):  
Sandrine Demanèche ◽  
Franck Bertolla ◽  
François Buret ◽  
Renaud Nalin ◽  
Alain Sailland ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Laboratory Scale ◽  
Electrical Field ◽  
Antibiotic Resistant ◽  
Electrical Fields ◽  
Bacterial Membranes ◽  
Naked Dna ◽  
Electrical Field Gradient ◽  
Lightning Discharges ◽  
Storm Cloud

ABSTRACT Electrical fields and current can permeabilize bacterial membranes, allowing for the penetration of naked DNA. Given that the environment is subjected to regular thunderstorms and lightning discharges that induce enormous electrical perturbations, the possibility of natural electrotransformation of bacteria was investigated. We demonstrated with soil microcosm experiments that the transformation of added bacteria could be increased locally via lightning-mediated current injection. The incorporation of three genes coding for antibiotic resistance (plasmid pBR328) into the Escherichia coli strain DH10B recipient previously added to soil was observed only after the soil had been subjected to laboratory-scale lightning. Laboratory-scale lightning had an electrical field gradient (700 versus 600 kV m−1) and current density (2.5 versus 12.6 kA m−2) similar to those of full-scale lightning. Controls handled identically except for not being subjected to lightning produced no detectable antibiotic-resistant clones. In addition, simulated storm cloud electrical fields (in the absence of current) did not produce detectable clones (transformation detection limit, 10−9). Natural electrotransformation might be a mechanism involved in bacterial evolution.

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