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Zegeye ED, Aspholm M. Efficient Electrotransformation of Bacillus thuringiensis for Gene Manipulation and Expression. Curr Protoc 2022; 2:e588. [PMID: 36350250 DOI: 10.1002/cpz1.588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Genetic manipulation of Bacillus spp., such as B. thuringiensis and B. cereus, is laborious and time consuming due to challenges in transformation of the plasmid DNA construct. Larger shuttle plasmids, such as pMAD, that are commonly used in markerless gene replacement are particularly difficult to transform into Bacillus spp. Here, we present robust protocols that work efficiently for the transformation of both small and large plasmid constructs into B. thuringiensis. Our protocols involve preparation of efficient electrocompetent Bacillus cells by cultivating the cells in the presence of a cell wall-weakening agent, followed by washing the cells with optimized solutions. The protocols further highlight the importance of using unmethylated plasmid DNA for the efficient transformation of B. thuringiensis. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Preparation of electrocompetent B. thuringiensis Basic Protocol 2: Transformation of B. thuringiensis.
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Affiliation(s)
- Ephrem Debebe Zegeye
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Marina Aspholm
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
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Wang JF, Li WL, Ahmad I, He BY, Wang LL, He T, Wang FP, Xu ZM, Li QS. Biomineralization of Cd 2+ and inhibition on rhizobacterial Cd mobilization function by Bacillus Cereus to improve safety of maize grains. CHEMOSPHERE 2021; 283:131095. [PMID: 34144288 DOI: 10.1016/j.chemosphere.2021.131095] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Reducing cadmium (Cd) bioavailability and rhizobacterial Cd mobilization functions in the rhizosphere via the inoculation of screened microbial inoculum is an environmental-friendly strategy to improve safety of crop grains. In this study, Bacillus Cereus, a model Cd resistant strain, was selected to explore its effects on Cd bioavailability and uptake, bacterial metabolic functions related to Cd mobilization. Results indicated that inoculation of Bacillus Cereus in maize roots of sand pot with water-soluble Cd (0.06-0.15 mg/kg) and soil pot with high Cd-contaminated soil (total Cd: 2.33 mg/kg; Cd extracted by NH4NO3: 38.6 μg/kg) could decrease water-soluble Cd ion concentration by 7.7-30.1% and Cd extracted with NH4NO3 solution by 7.8-22.5%, inducing Cd concentrations in maize grains reduced by 10.6-39.9% and 17.4-38.6%, respectively. Even for a single inoculation in soil, Cd concentration in maize grains still satisfy food safety requirements (Cd content: 0.1 mg/kg dry weight) due to its successful colonization on root surface of maize. Bacillus Cereus could enrich more plant growth promotion bacteria (PGPB) and down-regulate the expression of genes related to bacterial motility, membrane transports, carbon and nitrogen metabolism in the rhizosphere soil, decreasing Cd bioavailability in soil. Approximately 80% Cd2+ in media was transferred into intracellular, meanwhile Cd salts (sulfide and/or phosphate) were produced in Bacillus Cereus through biomineralization process. Overall, this study could provide a feasible method for improving safety of maize grains via the inoculation of Bacillus Cereus under Cd pollution.
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Affiliation(s)
- Jun-Feng Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Wan-Li Li
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Iftikhar Ahmad
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan
| | - Bao-Yan He
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Li-Li Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Tao He
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Fo-Peng Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Zhi-Min Xu
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Qu-Sheng Li
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
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Hu L, Guo S, Yan X, Zhang T, Xiang J, Fei Q. Exploration of an Efficient Electroporation System for Heterologous Gene Expression in the Genome of Methanotroph. Front Microbiol 2021; 12:717033. [PMID: 34421878 PMCID: PMC8373458 DOI: 10.3389/fmicb.2021.717033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/07/2021] [Indexed: 11/20/2022] Open
Abstract
One-carbon (C1) substrates such as methane and methanol have been considered as the next-generation carbon source in industrial biotechnology with the characteristics of low cost, availability, and bioconvertibility. Recently, methanotrophic bacteria naturally capable of converting C1 substrates have drawn attractive attention for their promising applications in C1-based biomanufacturing for the production of chemicals or fuels. Although genetic tools have been explored for metabolically engineered methanotroph construction, there is still a lack of efficient methods for heterologous gene expression in methanotrophs. Here, a rapid and efficient electroporation method with a high transformation efficiency was developed for a robust methanotroph of Methylomicrobium buryatense 5GB1. Based on the homologous recombination and high transformation efficiency, gene deletion and heterologous gene expression can be simultaneously achieved by direct electroporation of PCR-generated linear DNA fragments. In this study, the influence of several key parameters (competent cell preparation, electroporation condition, recovery time, and antibiotic concentration) on the transformation efficiency was investigated for optimum conditions. The maximum electroporation efficiency of 719 ± 22.5 CFU/μg DNA was reached, which presents a 10-fold improvement. By employing this method, an engineered M. buryatense 5GB1 was constructed to biosynthesize isobutyraldehyde by replacing an endogenous fadE gene in the genome with a heterologous kivd gene. This study provides a potential and efficient strategy and method to facilitate the cell factory construction of methanotrophs.
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Affiliation(s)
- Lizhen Hu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Shuqi Guo
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Tianqing Zhang
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jing Xiang
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China.,Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, China
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