Elaboration of an Electroporation Protocol for Lactobacillus brevis

2011 ◽  
Vol 393-395 ◽  
pp. 729-732
Author(s):  
Ying Zhang ◽  
Kun Cheng ◽  
Qiang Gao ◽  
Nian Fa Gao
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Plasmid Dna ◽  
Transformation Efficiency ◽  
Shuttle Vector ◽  
Lactobacillus Brevis ◽  
Buffer Concentration ◽  
Optimal Conditions ◽  
Industrial Performance

A detailed electroporation protocol had been established for Lactobacillus brevis TCCC13007. To optimize the conditions for electroporation ofL. brevis TCCC13007, anE.coli-Lactobacillusshuttle vector, pMG36e-1 was used. Several experiments that involved manipulation of cell wall weakening agent, electric field strength, electroporation buffer, concentration of transforming plasmid were carried out. Treatment of the recipient L. brevis TCCC13007 with 2% glycine in the growth medium for 3 h improved transformation efficiency. Other electroporation parameters were an electric field strength of 10 kv/cm and plasmid concentration of 0.9 μg. The presence of sorbitol in the electroporation buffer improved the transformation efficiency. Under the optimal conditions, the transformation efficiency was up to 5.1×104transformants per μg of pMG36e-1. The L. brevis TCCC13007 was also transformed by other plasmids such as pMG36e, pMG36e-2, pGK12, pLP825, pLP82H, respectively. The ability to electroporate plasmid DNA provided a tool forLactobacillus’s molecular bioengineering to improve their industrial performance.

scholarly journals Electrotransformation on Selected Plant Growth-Promoting Rhizobacteria (PGPR) and Chromobacterium violaceum

2020 ◽  
Vol 11 (1) ◽  
pp. 63-69
Author(s):  
WAI KEONG LOKE ◽  
Halimi Mohd Saud
Keyword(s):  
Plant Growth ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Transformation Efficiency ◽  
Pulse Length ◽  
Plant Growth Promoting Rhizobacteria ◽  
Length Range ◽  
Plant Growth Promoting ◽  
Growth Promoting

Electrotransformation was successfully transferred a 21.6 kb cosmid vector pLAFR1 into the selected Plant Growth-Promoting Rhizobacteria (PGPR) and Chromobacterium violaceum with maximum efficiency about 107 transformants/µg at electric field strength of 10kV/cm for shorter pulse length range between 4.1 to 4.4 milliseconds and about 108 transformants/µg at electric field strength of 5kV/cm for a longer pulse length range between 8.5 to 8.7 milliseconds. Longer incubation period will increase the transformation efficiency but continuing increasing the period after 20 hours will decrease the transformation efficiency.  

scholarly journals Efficient Electrotransformation of Bacteroides fragilis

2010 ◽  
Vol 76 (10) ◽  
pp. 3325-3332 ◽  
Author(s):  
Minoru Ichimura ◽  
Haruyuki Nakayama-Imaohji ◽  
Shin Wakimoto ◽  
Hidetoshi Morita ◽  
Tetsuya Hayashi ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Transformation Efficiency ◽  
Genetic Manipulation ◽  
Bacteroides Fragilis ◽  
Optimal Growth ◽  
Competent Cell ◽  
Suicide Vector

ABSTRACT This study describes refined electroporation parameters for efficient transformation of Bacteroides fragilis by plasmids prepared from laboratory strains of Escherichia coli. Development of the method used included determination of the optimal growth conditions for competent cell preparation, selectable antimicrobial resistance markers, electric field strength, and postpulse incubation time. Of the four E. coli-Bacteroides shuttle plasmids tested (pVAL-1, pVAL-2, pNLY1, and pLYL05), pLYL05 containing the cefoxitin resistance marker was found to be the most suitable for B. fragilis transformation, and it generated 2- to 900-fold more transformants (about 104 transformants per μg pLYL05 DNA) than the other plasmids. For the 72-h cultivation period tested, B. fragilis cells harvested at 48 h yielded the highest numbers of transformants. The transformation efficiency of pLYL05 increased linearly with the electric field strength over a range from 5.0 to 12.5 kV/cm. At least 3 h of postpulse incubation was required to maximize the transformation efficiency. For deletion of B. fragilis genes by homologous recombination, competent cells grown to early exponential phase and 12 h of postpulse incubation were required for efficient integration of the pLYL05-based suicide vector into the target site. The expected integration was obtained in B. fragilis strain NCTC9343 only when a homologously prepared (i.e., in vivo methylated) suicide vector was used. Spontaneous resolution of the diploid successfully deleted the expected genetic region. Our simple and efficient plasmid transfer method enabled disruption of a B. fragilis gene using in vivo-methylated targeted vectors. Our optimized electroporation parameters provide a useful tool for genetic manipulation of Bacteroides species.

Optical Measurement of the Electric Field Strength in a Gel Insulator

2016 ◽  
Vol 136 (10) ◽  
pp. 1420-1421
Author(s):  
Yusuke Tanaka ◽  
Yuji Nagaoka ◽  
Hyeon-Gu Jeon ◽  
Masaharu Fujii ◽  
Haruo Ihori
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Optical Measurement

Effect of external magnetic field on lane formation in driven pair-ion plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Swati Baruah ◽  
U. Sarma ◽  
R. Ganesh
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Coupling Parameter ◽  
Critical Parameters ◽  
Coulomb Coupling ◽  
Lane Formation ◽  
Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

scholarly journals Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Chronic Stroke ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Wilcoxon Rank Sum Test ◽  
Gait Parameters ◽  
The Mean

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

scholarly journals Optical properties of c-Plane InGaN/GaN single quantum wells as a function of total electric field strength

2019 ◽  
Vol 58 (SC) ◽  
pp. SCCB09 ◽  
Author(s):  
George M. Christian ◽  
Stefan Schulz ◽  
Simon Hammersley ◽  
Menno J. Kappers ◽  
Martin Frentrup ◽  
...  
Keyword(s):  
Optical Properties ◽  
Field Strength ◽  
Electric Field ◽  
Quantum Wells ◽  
Electric Field Strength ◽  
Single Quantum ◽  
Total Electric Field
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