Electro-transformation of Lactobacillus spp.
Overview
While there is a wide variety of methods used for the electrotransformation of Lactobacillus spp., there are a few steps all of them share. This page will list many of these protocols in a standard format so that you can compare them and choose the one that works for you. In some cases an apples to apples comparison may not be acceptable (e.g. the differences in electroporators can be dramatic) so be sure to check the actual paper.
Procedures
Josson (1989)
- Species = L. plantarum, L. casei.
- Dilution = 1/50
- Growth = MRS + 20mM DL threonine, 37°C, OD600=0.5-1.0
- Wash = 2x w/ water (RT°C)
- Buffer = 30% PEG 1000
- Voltage = 8,500 V/cm
- Recovery = 30min ice / 2hrs MRS
Bringel (1990)
- Species = L. plantarum
- Dilution = to OD600=0.05
- Growth = MRS + 1% Glycine, 0.75M Sorbitol, 30°C, Shake vigorously, OD600=0.3 (~4 hours)
- Wash = 3x w/ water (RT°C)
- Buffer = 30% PEG
- Voltage = 12,500 V/cm
- Recovery = 30min ice / 3hrs MRS
Posno (1991)
- Species =
- Dilution = 1/50
- Growth = 1% Glycine or Threonine, 37°C
- Wash = 5mM NaH2PO4 1mM MgCl2 (Ice Cold)
- Buffer = 0.3M Sucrose 5mM NaH2PO4 1mM MgCl2 (Ice Cold)
- Voltage = 7,000 V/cm
- Recovery = 90min MRS
Aukrust (1992)
- Species =
- Dilution = 1/50
- Growth = 1% Glycine, Shake
- Wash = 1mM MgCl2 (RT°C)
- Buffer = 30% PEG 1500
- Voltage = 7,500 V/cm
- Recovery = 2hrs MRS 0.5M Sucrose, 0.1M MgCl2
Wei (1995)
- Species =
- Dilution = 1/50
- Growth = 1% Glycine, 37°C
- Wash = 5mM NaH2PO4 1mM MgCl2 (0°C)
- Buffer = 0.9M Sucrose 3mM MgCl2
- Voltage = 12,500 V/cm
- Recovery = 2hrs MRS 0.5M Sucrose, 0.1M MgCl2
Berthier (1996)
- Species =
- Dilution = unspecified
- Growth = MRS, 30°C
- Wash = 10mM MgCl2 (0°C)
- Buffer = 0.5M Sucrose, 10%Glycerol
- Voltage = 7,000 V/cm
- Recovery = 2hrs MRS, 80mM MgCl2
Thompson (1996)
- Species =
- Dilution = 1/20
- Growth = MRS, 6% Glycine, 37°C
- Wash = 2X water, 1X 50mM EDTA, 2X 0.3M Sucrose ALL ICE COLD
- Buffer = 0.3M Sucrose
- Voltage = 7,500 V/cm
- Recovery = 2hrs MRS
Serror (2002)
- Species =
- Species =
- Dilution =
- Growth =
- Wash =
- Buffer =
- Voltage =
- Recovery =
Alegre (2004)
- Species =
- Species =
- Dilution =
- Growth =
- Wash =
- Buffer =
- Voltage =
- Recovery =
Mason (2005)
- Species =
- Dilution = 1/6
- Growth = MRS, 8% Glycine, 90mins, 37°C
- Wash = 2X water; 1X 50mM EDTA; 2X 0.3M Sucrose. ALL ICE COLD
- Buffer = 0.3M Sucrose
- Voltage = 7,500 V/cm
- Recovery = 2hrs MRS
Notes
All questions, input and feedback are welcome!
- Centrifugation at 4000 rpm for 2 minutes was sufficient to pellet the competent cells to give a clear supernatant.
- Most of these papers use the Bio-Rad Gene Pulser and have time constants in the range of 9-10 ms with the lower voltages (7.5-9kV/cm). If you're using a preset electroporator (like the Eppendorf 2510) you should try a higher voltage (~1200) as your time constand will be in thee range of 5-6 ms. If you're using PEG in your electroporation buffer expect your time constant to be significantly lower.
References
This protocol is based mostly on the protocols described by Thompson and Collins (1996) and Mason et al. (2004) but other literature are also listed.
Alegre et al (FEMS Microbiology Letters 241 (2004) 73-77)
Aukrust, T. and H. Blom (1992). "TRANSFORMATION OF LACTOBACILLUS STRAINS USED IN MEAT AND VEGETABLE FERMENTATIONS." Food Research International 25(4): 253-261.
Berthier, F., M. Zagorec, et al. (1996). "Efficient transformation of Lactobacillus sake by electroporation." Microbiology-Uk 142: 1273-1279.
Josson, K., T. Scheirlinck, et al. (1989). "CHARACTERIZATION OF A GRAM-POSITIVE BROAD-HOST-RANGE PLASMID ISOLATED FROM LACTOBACILLUS-HILGARDII." Plasmid 21(1): 9-20.
Mason, C. K., M. A. Collins, et al. (2005). "Modified electroporation protocol for Lactobacilli isolated frorn the chicken crop facilitates transformation and the use of a genetic tool." Journal of Microbiological Methods 60(3): 353-363.
Posno, M., R. J. Leer, et al. (1991). "INCOMPATIBILITY OF LACTOBACILLUS VECTORS WITH REPLICONS DERIVED FROM SMALL CRYPTIC LACTOBACILLUS PLASMIDS AND SEGREGATIONAL INSTABILITY OF THE INTRODUCED VECTORS." Applied and Environmental Microbiology 57(6): 1822-1828.
Thompson, K. and M. A. Collins (1996). "Improvement in electroporation efficiency for Lactobacillus plantarum by the inclusion of high concentrations of glycine in the growth medium." Journal of Microbiological Methods 26(1-2): 73-79.
Wei, M. Q., C. M. Rush, et al. (1995). "AN IMPROVED METHOD FOR THE TRANSFORMATION OF LACTOBACILLUS STRAINS USING ELECTROPORATION." Journal of Microbiological Methods 21(1): 97-109.
Contact
- morto077@uottawa.ca
- mas853@psu.edu
or instead, discuss this protocol.
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