scholarly journals Analysis of the efficiency factors of electrotransformation of Bacillus subtilis to inactivate the aroK gene by the method of homologous recombination

Author(s):  
Yui Chao ◽  
Aleksei V. Lahodzich

A hyper-osmotic electrotransformation method was developed for strain Bacillus subtilis. Sorbitol and mannitol are included in the hyper-osmotic electroporation medium and recovery medium. In this study, the hyper-osmotic electroporation method was optimised to increase the transformation efficiency of B. subtilis strain 5434 (non-transformable by chemical methods) by 430 fold, with a maximum value of 8.6 ⋅ 105 CFU/µg of integrative plasmid DNA. With the electroporation setted 25 µF, 23 kV/cm, 200 Ω, the method was optimised as follows: a) the OD600 value of the bacterial culture solution was increased to about 1.2, which significantly enhanced survival of bacteria and quantity of viable B.subtilis strain 5434 cells after electroporation; b) the elution frequency of washing solution (hyper-osmotic electroporation medium) for complement cells was increased from 3 to 5 times, resulted in significantly reducing the conductivity of the hyper-osmotic electoporation medium with competent cells (electrocompetent cultue), and effectively extending the pulse time under the same electric field strength; c) quantity of integrative plasmid DNA added to hyper-osmotic electrocompetent culture was optimised. These results indicate that increasing the number of viable B. subtilis strain 5434 cells and reducing the number of metal ions in the electroporation solution mix (integrative plasmid DNA, competent cells of B. subtilis strain 5434, electroporation medium) are useful approach to improve transfomation efficiency of B. subtilis strain 5434. Concentration of shikimic acid in the fermentation medium was quantified by high performance liquid chromatography. Quantification of shikimic acid revealed that B. subtilis strain 5434p4SA produced 403.98 ± 9.1 µg/mL of shikimic acid.

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3457 ◽  
Author(s):  
Te-Sheng Chang ◽  
Chien-Min Chiang ◽  
Yu-Han Kao ◽  
Jiumn-Yih Wu ◽  
Yu-Wei Wu ◽  
...  

Ganoderic acid A (GAA) is a bioactive triterpenoid isolated from the medicinal fungus Ganoderma lucidum. Our previous study showed that the Bacillus subtilis ATCC (American type culture collection) 6633 strain could biotransform GAA into compound (1), GAA-15-O-β-glucoside, and compound (2). Even though we identified two glycosyltransferases (GT) to catalyze the synthesis of GAA-15-O-β-glucoside, the chemical structure of compound (2) and its corresponding enzyme remain elusive. In the present study, we identified BsGT110, a GT from the same B. subtilis strain, for the biotransformation of GAA into compound (2) through acidic glycosylation. BsGT110 showed an optimal glycosylation activity toward GAA at pH 6 but lost most of its activity at pH 8. Through a scaled-up production, compound (2) was successfully isolated using preparative high-performance liquid chromatography and identified to be a new triterpenoid glucoside (GAA-26-O-β-glucoside) by mass and nuclear magnetic resonance spectroscopy. The results of kinetic experiments showed that the turnover number (kcat) of BsGT110 toward GAA at pH 6 (kcat = 11.2 min−1) was 3-fold higher than that at pH 7 (kcat = 3.8 min−1), indicating that the glycosylation activity of BsGT110 toward GAA was more active at acidic pH 6. In short, we determined that BsGT110 is a unique GT that plays a role in the glycosylation of triterpenoid at the C-26 position under acidic conditions, but loses most of this activity under alkaline ones, suggesting that acidic solutions may enhance the catalytic activity of this and similar types of GTs toward triterpenoids.


Genetics ◽  
1989 ◽  
Vol 121 (3) ◽  
pp. 411-422
Author(s):  
M F Wojciechowski ◽  
M A Hoelzer ◽  
R E Michod

Abstract In Bacillus subtilis, DNA repair and recombination are intimately associated with competence, the physiological state in which the bacterium can bind, take up and recombine exogenous DNA. Previously, we have shown that the homologous DNA transformation rate (ratio of transformants to total cells) increases with increasing UV dosage if cells are transformed after exposure to UV radiation (UV-DNA), whereas the transformation rate decreases if cells are transformed before exposure to UV (DNA-UV). In this report, by using different DNA repair-deficient mutants, we show that the greater increase in transformation rate in UV-DNA experiments than in DNA-UV experiments does not depend upon excision repair or inducible SOS-like repair, although certain quantitative aspects of the response do depend upon these repair systems. We also show that there is no increase in the transformation rate in a UV-DNA experiment when repair and recombination proficient cells are transformed with nonhomologous plasmid DNA, although the results in a DNA-UV experiment are essentially unchanged by using plasmid DNA. We have used din operon fusions as a sensitive means of assaying for the expression of genes under the control of the SOS-like regulon in both competent and noncompetent cell subpopulations as a consequence of competence development and our subsequent experimental treatments. Results indicate that the SOS-like system is induced in both competent and noncompetent subpopulations in our treatments and so should not be a major factor in the differential response in transformation rate observed in UV-DNA and DNA-UV treatments. These results provide further support to the hypothesis that the evolutionary function of competence is to bring DNA into the cell for use as template in the repair of DNA damage.


2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Daniel R. Reuß ◽  
Andrea Thürmer ◽  
Rolf Daniel ◽  
Wim J. Quax ◽  
Jörg Stülke

Bacillus subtilis ∆6 is a genome-reduced strain that was cured from six prophages and AT-rich islands. This strain is of great interest for biotechnological applications. Here, we announce the full-genome sequence of this strain. Interestingly, the conjugative element ICE Bs 1 has most likely undergone self-excision in B. subtilis ∆6.


1979 ◽  
Vol 179 (2) ◽  
pp. 333-339 ◽  
Author(s):  
A Y Strongin ◽  
D I Gorodetsky ◽  
I A Kuznetsova ◽  
V V Yanonis ◽  
Z T Abramov ◽  
...  

Intracellular serine proteinase was isolated from sporulating cells of Bacillus subtilis Marburg 168 by gramicidin S-Sepharose 4B affinity chromatography. The enzymological characteristics, the amino acid composition and the 19 residues of the N-terminal sequence of the enzyme are reported. The isolated proteinase was closely related to, but not completely identical with, the intracellular serine proteinase of B. subtilis A-50. The divergence between these two intracellular enzymes was less than that between the corresponding extracellular serine proteinases (subtilisins) of types Carlsberg and BPN′!, produced by these bacterial strains. This may be connected with the more strict selection constraints imposed in intracellular enzymes during evolution.


2017 ◽  
Vol 12 (1) ◽  
pp. 255-263 ◽  
Author(s):  
Kanjana Thumanu ◽  
Darawadee Wongchalee ◽  
Mathukorn Sompong ◽  
Piyaporn Phansak ◽  
Toan Le Thanh ◽  
...  

1988 ◽  
Vol 56 (1) ◽  
pp. 67-70 ◽  
Author(s):  
C.P. Rubinstein ◽  
L.C. Moratinos ◽  
O.A. Coso ◽  
C. Sánchez-Rivas

Sign in / Sign up

Export Citation Format

Share Document