1
|
Bhattacharyya A, Mavrodi O, Bhowmik N, Weller D, Thomashow L, Mavrodi D. Bacterial biofilms as an essential component of rhizosphere plant-microbe interactions. METHODS IN MICROBIOLOGY 2023; 53:3-48. [PMID: 38415193 PMCID: PMC10898258 DOI: 10.1016/bs.mim.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Affiliation(s)
- Ankita Bhattacharyya
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Olga Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Niladri Bhowmik
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - David Weller
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Linda Thomashow
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Dmitri Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| |
Collapse
|
2
|
Zhang G, Lin M, Qin M, Xie Q, Liang M, Jiang J, Dai H, Xu S, Feng S, Liao M. Establishing Heterologous Production of Microcins J25 and Y in Bacillus subtilis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:5600-5613. [PMID: 36995900 DOI: 10.1021/acs.jafc.3c00675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Microcin J25 (MccJ25) and microcin Y (MccY) are lasso peptides and considered potential alternatives to antibiotics and harmful preservatives. The combination of these two microcins can provide a wide antimicrobial spectrum against food-borne Salmonella. Currently, MccJ25 and MccY are produced using Escherichia coli expression systems; however, the entire production process is accompanied by negative effects from endotoxins. In this study, we identified Bacillus subtilis as a suitable host for MccJ25 and MccY production. High-level production of microcins was achieved by promoter optimization, host strain selection, and recombinant expression. The engineered strains produced maximum yields of 2.827 μM MccJ25 and 1.481 μM MccY. This is the first study to demonstrate the expression of MccJ25 and MccY in B. subtilis, and it offers a few engineered strains that are without antibiotic resistance markers, inducer-free, sporulation-deficient, and free of the negative effects of endotoxins for antibacterial therapy and food preservation.
Collapse
Affiliation(s)
- Guangwen Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Min Lin
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Miaomiao Qin
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Qianmei Xie
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Mingzhi Liang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Jinfei Jiang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Huilin Dai
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Siqi Xu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
| | - Saixiang Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, P. R. China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, P. R. China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou 510642, P. R. China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou 510642, P. R. China
| | - Ming Liao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, P. R. China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, P. R. China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, P. R. China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou 510642, P. R. China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou 510642, P. R. China
| |
Collapse
|
3
|
He H, Choi Y, Wu SJ, Fang X, Anderson AK, Liou SY, Roberts MC, Lee Y, Dodd MC. Application of Nucleotide-Based Kinetic Modeling Approaches to Predict Antibiotic Resistance Gene Degradation during UV- and Chlorine-Based Wastewater Disinfection Processes: From Bench- to Full-Scale. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15141-15155. [PMID: 36098629 DOI: 10.1021/acs.est.2c00567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study investigated antibiotic resistance gene (ARG) degradation kinetics in wastewaters during bench- and full-scale treatment with UV light and chlorine─with the latter maintained as free available chlorine (FAC) in low-ammonia wastewater and converted into monochloramine (NH2Cl) in high-ammonia wastewater. Twenty-three 142-1509 bp segments (i.e., amplicons) of seven ARGs (blt, mecA, vanA, tet(A), ampC, blaNDM, blaKPC) and the 16S rRNA gene from antibiotic resistant bacteria (ARB) strains Bacillus subtilis, Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae were monitored as disinfection targets by qPCR. Rate constants for ARG and 16S rRNA gene amplicon degradation by UV, FAC, and NH2Cl were measured in phosphate buffer and used to expand and validate several recently developed approaches to predict DNA segment degradation rate constants based solely on their nucleotide contents, which were then applied to model ARG degradation during bench-scale treatment in buffer and wastewater matrixes. Kinetics of extracellular and intracellular ARG degradation by UV and FAC were well predicted up to ∼1-2-log10 elimination, although with decreasing accuracy at higher levels for intracellular genes, while NH2Cl yielded minimal degradation under all conditions (agreeing with predictions). ARB inactivation kinetics varied substantially across strains, with intracellular gene degradation lagging cell inactivation in each case. ARG degradation levels observed during full-scale disinfection at two wastewater treatment facilities were consistent with bench-scale measurements and predictions, where UV provided ∼1-log10 ARG degradation, and chlorination of high-ammonia wastewater (dominated by NH2Cl) yielded minimal ARG degradation.
Collapse
Affiliation(s)
- Huan He
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195, United States
| | - Yegyun Choi
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Sean J Wu
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195, United States
| | - Xuzhi Fang
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195, United States
| | - Annika K Anderson
- Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Sin-Yi Liou
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195, United States
| | - Marilyn C Roberts
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105, United States
| | - Yunho Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Michael C Dodd
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195, United States
| |
Collapse
|
4
|
Abstract
Some Bacillus species, such as B. velezensis, are important members of the plant-associated microbiome, conferring protection against phytopathogens. However, our knowledge about multitrophic interactions determining the ecological fitness of these biocontrol bacteria in the competitive rhizosphere niche is still limited. Here, we investigated molecular mechanisms underlying interactions between B. velezensis and Pseudomonas as a soil-dwelling competitor. Upon their contact-independent in vitro confrontation, a multifaceted macroscopic outcome was observed and characterized by Bacillus growth inhibition, white line formation in the interaction zone, and enhanced motility. We correlated these phenotypes with the production of bioactive secondary metabolites and identified specific lipopeptides as key compounds involved in the interference interaction and motile response. Bacillus mobilizes its lipopeptide surfactin not only to enhance motility but also to act as a chemical trap to reduce the toxicity of lipopeptides formed by Pseudomonas. We demonstrated the relevance of these unsuspected roles of lipopeptides in the context of competitive tomato root colonization by the two bacterial genera. IMPORTANCE Plant-associated Bacillus velezensis and Pseudomonas spp. represent excellent model species as strong producers of bioactive metabolites involved in phytopathogen inhibition and the elicitation of plant immunity. However, the ecological role of these metabolites during microbial interspecies interactions and the way their expression may be modulated under naturally competitive soil conditions has been poorly investigated. Through this work, we report various phenotypic outcomes from the interactions between B. velezensis and 10 Pseudomonas strains used as competitors and correlate them with the production of specific metabolites called lipopeptides from both species. More precisely, Bacillus overproduces surfactin to enhance motility, which also, by acting as a chemical trap, reduces the toxicity of other lipopeptides formed by Pseudomonas. Based on data from interspecies competition on plant roots, we assume this would allow Bacillus to gain fitness and persistence in its natural rhizosphere niche. The discovery of new ecological functions for Bacillus and Pseudomonas secondary metabolites is crucial to rationally design compatible consortia, more efficient than single-species inoculants, to promote plant health and growth by fighting economically important pathogens in sustainable agriculture.
Collapse
|
5
|
Gong JS, Ye JP, Tao LY, Su C, Qin J, Zhang YY, Li H, Li H, Xu ZH, Shi JS. Efficient keratinase expression via promoter engineering strategies for degradation of feather wastes. Enzyme Microb Technol 2020; 137:109550. [PMID: 32423677 DOI: 10.1016/j.enzmictec.2020.109550] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 01/29/2020] [Accepted: 03/08/2020] [Indexed: 01/13/2023]
Abstract
Keratinases are promising alternatives over ordinary proteases in several industrial applications due to their unique properties compared with their counterparts in the protease categories. However, their large-scale industrial application is limited by the low expression and poor fermentation efficiency of keratinase. Here, we demonstrate that the expression level of keratinase can be improved by constructing a more efficient enzyme expression system hereby enables the highest production titer as regarding recombinant keratinase production to date. Specially, ten promoters were evaluated and the aprE promoter exhibits a significant promotion of keratinase (kerBv) titer from 165 U/mL to 2605 U/mL in Bacillus subtilis. The batch fermentation mode resulted in a maximum keratinase activity of 7176 U/mL at 36 h in a 5-L fermenter. Furthermore, the extracellular keratinase activity attained up to 16,860 U/mL via fed-batch fermentation within 30 h. The combination of keratinase with l-cysteine brings about 66.4 % degree of degradation of feather. Our work provides a new insight into the development of efficient keratinase fermentation processes with B. subtilis cell factory.
Collapse
Affiliation(s)
- Jin-Song Gong
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Jin-Peng Ye
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Li-Yan Tao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Chang Su
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Jiufu Qin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Yan-Yan Zhang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Heng Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Hui Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Zheng-Hong Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, PR China
| | - Jin-Song Shi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China.
| |
Collapse
|
6
|
Price MA, Cruz R, Bryson J, Escalettes F, Rosser SJ. Expanding and understanding the CRISPR toolbox for
Bacillus subtilis
with MAD7 and dMAD7. Biotechnol Bioeng 2020; 117:1805-1816. [DOI: 10.1002/bit.27312] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/15/2020] [Accepted: 02/19/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Marcus A. Price
- School of Biological Sciences, Institute of Quantitative Biology, Biochemistry, and BiotechnologyUniversity of Edinburgh Edinburgh UK
| | - Rita Cruz
- Molecular Biology DepartmentIngenza Ltd., Roslin Innovation Centre Roslin UK
| | - James Bryson
- School of Biological Sciences, UK Centre for Mammalian Synthetic BiologyUniversity of Edinburgh Edinburgh UK
| | - Franck Escalettes
- Molecular Biology DepartmentIngenza Ltd., Roslin Innovation Centre Roslin UK
| | - Susan J. Rosser
- School of Biological Sciences, Institute of Quantitative Biology, Biochemistry, and BiotechnologyUniversity of Edinburgh Edinburgh UK
- School of Biological Sciences, UK Centre for Mammalian Synthetic BiologyUniversity of Edinburgh Edinburgh UK
- Centre for Synthetic and Systems Biology and UK Centre for Mammalian Synthetic Biology, School of Biological SciencesUniversity of Edinburgh UK
| |
Collapse
|
7
|
Guanidine Riboswitch-Regulated Efflux Transporters Protect Bacteria against Ionic Liquid Toxicity. J Bacteriol 2019; 201:JB.00069-19. [PMID: 30988034 DOI: 10.1128/jb.00069-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/09/2019] [Indexed: 11/20/2022] Open
Abstract
Plant cell walls contain a renewable, nearly limitless supply of sugar that could be used to support microbial production of commodity chemicals and biofuels. Imidazolium ionic liquid (IIL) solvents are among the best reagents for gaining access to the sugars in this otherwise recalcitrant biomass. However, the sugars from IIL-treated biomass are inevitably contaminated with residual IILs that inhibit growth in bacteria and yeast, blocking biochemical production by these organisms. IIL toxicity is, therefore, a critical roadblock in many industrial biosynthetic pathways. Although several IIL-tolerant (IILT) bacterial and yeast isolates have been identified in nature, few genetic mechanisms have been identified. In this study, we identified two IILT Bacillus isolates as well as a spontaneous IILT Escherichia coli lab strain that are tolerant to high levels of two widely used IILs. We demonstrate that all three IILT strains contain one or more pumps of the small multidrug resistance (SMR) family, and two of these strains contain mutations that affect an adjacent regulatory guanidine riboswitch. Furthermore, we show that the regulation of E. coli sugE by the guanidine II riboswitch can be exploited to promote IIL tolerance by the simple addition of guanidine to the medium. Our results demonstrate the critical role that transporter genes play in IIL tolerance in their native bacterial hosts. The study presented here is another step in engineering IIL tolerance into industrial strains toward overcoming this key gap in biofuels and industrial biochemical production processes.IMPORTANCE This study identifies bacteria that are tolerant to ionic liquid solvents used in the production of biofuels and industrial biochemicals. For industrial microbiology, it is essential to find less-harmful reagents and microbes that are resistant to their cytotoxic effects. We identified a family of small multidrug resistance efflux transporters, which are responsible for the tolerance of these strains. We also found that this resistance can be caused by mutations in the sequences of guanidine-specific riboswitches that regulate these efflux pumps. Extending this knowledge, we demonstrated that guanidine itself can promote ionic liquid tolerance. Our findings will inform genetic engineering strategies that improve conversion of cellulosic sugars into biofuels and biochemicals in processes where low concentrations of ionic liquids surpass bacterial tolerance.
Collapse
|
8
|
Prunty MP, Noone D, Devine KM. The distinct PhoPR mediated responses to phosphate limitation in Bacillus subtilis subspecies subtilis and spizizenii stem from differences in wall teichoic acid composition and metabolism. Mol Microbiol 2018; 109:23-40. [PMID: 29644746 DOI: 10.1111/mmi.13965] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2018] [Indexed: 11/28/2022]
Abstract
The PhoPR-mediated response to phosphate limitation (PHO response) in Bacillus subtilis subsp subtilis is amplified and maintained by reducing the level of Lipid VG composed of poly(glycerol phosphate), a wall teichoic acid (WTA) biosynthetic intermediate that inhibits PhoR autokinase activity. However, the reduction in Lipid VG level is effected by activated PhoP∼P, raising the question of how the PHO response is first initiated. Furthermore, that WTA is composed of poly(ribitol phosphate) in Bacillus subtilis subsp spizizenii prompted an investigation of how the PHO response is regulated in that bacterium. We report that the PHO responses of B. subtilis subsp subtilis and subsp spizizenii are distinct. The PhoR kinases of the two B. subtilis subspecies are functionally equivalent and are activated either by the TagA/TarA or TagB/TarB enzyme product. However, they are inhibited by Lipid VG composed of poly(glycerol phosphate) but not by Lipid VR composed of poly(ribitol phosphate). Therefore, the distinctive PHO responses of these B. subtilis subspecies stem from the differential sensitivity of PhoR kinases to the polyol composition of Lipid V and from the genomic organization of WTA biosynthetic genes and the regulation of their expression.
Collapse
Affiliation(s)
- Michael P Prunty
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - David Noone
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Kevin M Devine
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
9
|
Heidrich J, Junglas B, Grytsyk N, Hellmann N, Rusitzka K, Gebauer W, Markl J, Hellwig P, Schneider D. Mg 2+ binding triggers rearrangement of the IM30 ring structure, resulting in augmented exposure of hydrophobic surfaces competent for membrane binding. J Biol Chem 2018; 293:8230-8241. [PMID: 29618510 DOI: 10.1074/jbc.ra117.000991] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/20/2018] [Indexed: 12/24/2022] Open
Abstract
The "inner membrane-associated protein of 30 kDa" (IM30), also known as "vesicle-inducing protein in plastids 1" (Vipp1), is found in the majority of photosynthetic organisms that use oxygen as an energy source, and its occurrence appears to be coupled to the existence of thylakoid membranes in cyanobacteria and chloroplasts. IM30 is most likely involved in thylakoid membrane biogenesis and/or maintenance, and has recently been shown to function as a membrane fusion protein in presence of Mg2+ However, the precise role of Mg2+ in this process and its impact on the structure and function of IM30 remains unknown. Here, we show that Mg2+ binds directly to IM30 with a binding affinity of ∼1 mm Mg2+ binding compacts the IM30 structure coupled with an increase in the thermodynamic stability of the proteins' secondary, tertiary, and quaternary structures. Furthermore, the structural alterations trigger IM30 double ring formation in vitro because of increased exposure of hydrophobic surface regions. However, in vivo Mg2+-triggered exposure of hydrophobic surface regions most likely modulates membrane binding and induces membrane fusion.
Collapse
Affiliation(s)
- Jennifer Heidrich
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Benedikt Junglas
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Natalia Grytsyk
- Laboratoire de bioelectrochimie et spectroscopie, UMR 7140, CNRS Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, Germany
| | - Nadja Hellmann
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Kristiane Rusitzka
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Wolfgang Gebauer
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Jürgen Markl
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Petra Hellwig
- Laboratoire de bioelectrochimie et spectroscopie, UMR 7140, CNRS Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany.
| |
Collapse
|
10
|
Toymentseva AA, Mascher T, Sharipova MR. Regulatory Characteristics of Bacillus pumilus Protease Promoters. Curr Microbiol 2017; 74:550-559. [PMID: 28258295 DOI: 10.1007/s00284-017-1212-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/03/2017] [Indexed: 02/03/2023]
Abstract
Expression of extracellular protease genes of Bacilli is subject to regulation by many positive and negative regulators. Here we analyzed 5' regulatory regions of genes encoding proteolytic proteases AprBp, GseBp, and MprBp from Bacillus pumilus strain 3-19. Gfp fusion constructs with upstream genomic regions of different lengths were created for all three genes to identify their natural promoters (regulatory regions). Our results suggest that the aprBp gene, encoding the major subtilisin-like protease, has the most extensive promoter region of approximately 445 bp, while the minor protease genes encoding glutamyl endopeptidase (gseBp) and metalloproteinase (mprBp) are preceded by promoters of 150 and 250 bp in length, respectively. Promoter analysis of P aprBp -gfpmu3 and P gseBp -gfpmu3 reporter fusion constructs in degU and spo0A mutants indicates a positive regulatory effect of DegU and Spo0A on protease expression, while the disruption of abrB, sinR, and scoC repressor genes did not significantly affect promoter activities of all protease genes. On the other hand, the expression of P aprBp -gfpmu3 and P gseBp -gfpmu3 reporters increased 1.6- and 3.0-fold, respectively, in sigD-deficient cells, indicating that the prevention of motility gene expression promotes protease expression. Our results indicate that all examined regulators regulated serine proteases production in B. subtilis.
Collapse
Affiliation(s)
- Anna A Toymentseva
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan, 18 Kremlyovskaya St., Kazan, Russian Federation, 420008.
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany
| | - Margarita R Sharipova
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan, 18 Kremlyovskaya St., Kazan, Russian Federation, 420008
| |
Collapse
|
11
|
Chen J, Zhao L, Fu G, Zhou W, Sun Y, Zheng P, Sun J, Zhang D. A novel strategy for protein production using non-classical secretion pathway in Bacillus subtilis. Microb Cell Fact 2016; 15:69. [PMID: 27125780 PMCID: PMC4850722 DOI: 10.1186/s12934-016-0469-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/21/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The Gram-positive bacterium Bacillus subtilis has been widely used as a cell factory for the production of proteins due to its generally regarded as safe (GRAS) nature and secretion capability. Of the known secretory pathways in B. subtilis, the majority of proteins are exported from the cytoplasm by Sec pathway, Tat pathway and ABC transporters, etc. However, the production of heterologous proteins by B. subtilis is unfortunately not that straight forward because of the bottlenecks in classical secretion pathways. The aim of this work is to explore a new method for protein production based on non-classical secretion pathway. RESULTS One D-psicose 3-epimerase (RDPE) which converts D-fructose into D-psicose from Ruminococcus sp. 5_1_39BFAA was successfully and substantially secreted into the extracellular milieu without the direction of signal peptide. Subsequently, we demonstrated that RDPE contained no native signal peptide, and the secretion of RDPE was not dependent on Sec or Tat pathway or due to cell lysis, which indicated that RDPE is a non-classically secreted protein. Then, we attempted to evaluate the possibility of using RDPE as a signal to export eighteen reporter proteins into the culture medium. Five of eleven homologous proteins, two of five heterologous proteins from other bacterium and two heterologous proteins of eukaryotic source were successfully secreted into the extracellular milieu at different secretion levels when they were fused to RDPE mediated by a flexible 21-bp linker to keep a distance between two single proteins. Furthermore, the secretion rates of two fusion proteins (RDPE-DnaK and RDPE-RFP) reached more than 50 %. In addition, most of the fusion proteins retained enzyme or biological activity of their corresponding target proteins, and all of the fusions still had the activity of RDPE. CONCLUSIONS We found and identified a heterologous non-classically secreted protein RDPE, and showed that RDPE could direct proteins of various types into the culture medium, and thus non-classical protein secretion pathway can be used as a novel secretion pathway for recombinant proteins. This novel strategy for recombinant protein production is helpful to make B. subtilis as a more ideal cell factory for protein production.
Collapse
Affiliation(s)
- Jingqi Chen
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Liuqun Zhao
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Gang Fu
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />National Engineering Laboratory for Industrial Enzymes, Tianjin, 300308 People’s Republic of China
| | - Wenjuan Zhou
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Yuanxia Sun
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />National Engineering Laboratory for Industrial Enzymes, Tianjin, 300308 People’s Republic of China
| | - Ping Zheng
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Jibin Sun
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Dawei Zhang
- />Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- />National Engineering Laboratory for Industrial Enzymes, Tianjin, 300308 People’s Republic of China
| |
Collapse
|
12
|
Wolf D, Rippa V, Mobarec JC, Sauer P, Adlung L, Kolb P, Bischofs IB. The quorum-sensing regulator ComA from Bacillus subtilis activates transcription using topologically distinct DNA motifs. Nucleic Acids Res 2015; 44:2160-72. [PMID: 26582911 PMCID: PMC4797271 DOI: 10.1093/nar/gkv1242] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/30/2015] [Indexed: 11/27/2022] Open
Abstract
ComA-like transcription factors regulate the quorum response in numerous Gram-positive bacteria. ComA proteins belong to the tetrahelical helix-turn-helix superfamily of transcriptional activators, which bind as homodimers to inverted sequence repeats in the DNA. Here, we report that ComA from Bacillus subtilis recognizes a topologically distinct motif, in which the binding elements form a direct repeat. We provide in vitro and in vivo evidence that the canonical and non-canonical site play an important role in facilitating type I and type II promoter activation, respectively, by interacting with different subunits of RNA polymerase. We furthermore show that there is a variety of contexts in which the non-canonical site can occur and identify new direct target genes that are located within the integrative and conjugative element ICEBs1. We therefore suggest that ComA acts as a multifunctional transcriptional activator and provides a striking example for complexity in protein–DNA interactions that evolved in the context of quorum sensing.
Collapse
Affiliation(s)
- Diana Wolf
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Valentina Rippa
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Juan Carlos Mobarec
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Patricia Sauer
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Lorenz Adlung
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Ilka B Bischofs
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| |
Collapse
|
13
|
Genome-wide analysis of phosphorylated PhoP binding to chromosomal DNA reveals several novel features of the PhoPR-mediated phosphate limitation response in Bacillus subtilis. J Bacteriol 2015; 197:1492-506. [PMID: 25666134 DOI: 10.1128/jb.02570-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The PhoPR two-component signal transduction system controls one of three responses activated by Bacillus subtilis to adapt to phosphate-limiting conditions (PHO response). The response involves the production of enzymes and transporters that scavenge for phosphate in the environment and assimilate it into the cell. However, in B. subtilis and some other Firmicutes bacteria, cell wall metabolism is also part of the PHO response due to the high phosphate content of the teichoic acids attached either to peptidoglycan (wall teichoic acid) or to the cytoplasmic membrane (lipoteichoic acid). Prompted by our observation that the phosphorylated WalR (WalR∼P) response regulator binds to more chromosomal loci than are revealed by transcriptome analysis, we established the PhoP∼P bindome in phosphate-limited cells. Here, we show that PhoP∼P binds to the chromosome at 25 loci: 12 are within the promoters of previously identified PhoPR regulon genes, while 13 are newly identified. We extend the role of PhoPR in cell wall metabolism showing that PhoP∼P binds to the promoters of four cell wall-associated operons (ggaAB, yqgS, wapA, and dacA), although none show PhoPR-dependent expression under the conditions of this study. We also show that positive autoregulation of phoPR expression and full induction of the PHO response upon phosphate limitation require PhoP∼P binding to the 3' end of the phoPR operon. IMPORTANCE The PhoPR two-component system controls one of three responses mounted by B. subtilis to adapt to phosphate limitation (PHO response). Here, establishment of the phosphorylated PhoP (PhoP∼P) bindome enhances our understanding of the PHO response in two important ways. First, PhoPR plays a more extensive role in adaptation to phosphate-limiting conditions than was deduced from transcriptome analyses. Among 13 newly identified binding sites, 4 are cell wall associated (ggaAB, yqgS, wapA, and dacA), revealing that PhoPR has an extended involvement in cell wall metabolism. Second, amplification of the PHO response must occur by a novel mechanism since positive autoregulation of phoPR expression requires PhoP∼P binding to the 3' end of the operon.
Collapse
|
14
|
Trauth S, Bischofs IB. Ectopic integration vectors for generating fluorescent promoter fusions in Bacillus subtilis with minimal dark noise. PLoS One 2014; 9:e98360. [PMID: 24874808 PMCID: PMC4038550 DOI: 10.1371/journal.pone.0098360] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/01/2014] [Indexed: 11/19/2022] Open
Abstract
Fluorescent protein promoter reporters are important tools that are widely used for diverse purposes in microbiology, systems biology and synthetic biology and considerable engineering efforts are still geared at improving the sensitivity of the reporter systems. Here we focus on dark noise, i.e. the signal that is generated by the empty vector control. We quantitatively characterize the dark noise of a few common bacterial reporter systems by single cell microscopy. All benchmarked reporter systems generated significant amounts of dark noise that exceed the cellular autofluorescence to different extents. We then reengineered a multicolor set of fluorescent ectopic integration vectors for Bacillus subtilis by introducing a terminator immediately upstream of the promoter insertion site, resulting in an up to 2.7-fold reduction of noise levels. The sensitivity and dynamic range of the new high-performance pXFP_Star reporter system is only limited by cellular autofluorescence. Moreover, based on studies of the rapE promoter of B. subtilis we show that the new pXFP_Star reporter system reliably reports on the weak activity of the rapE promoter whereas the original reporter system fails because of transcriptional interference. Since the pXFP_Star reporter system properly isolates the promoter from spurious transcripts, it is a particularly suitable tool for quantitative characterization of weak promoters in B. subtilis.
Collapse
Affiliation(s)
- Stephanie Trauth
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Heidelberg, Germany
| | - Ilka B. Bischofs
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Heidelberg, Germany
- * E-mail:
| |
Collapse
|
15
|
Radeck J, Kraft K, Bartels J, Cikovic T, Dürr F, Emenegger J, Kelterborn S, Sauer C, Fritz G, Gebhard S, Mascher T. The Bacillus BioBrick Box: generation and evaluation of essential genetic building blocks for standardized work with Bacillus subtilis. J Biol Eng 2013; 7:29. [PMID: 24295448 PMCID: PMC4177231 DOI: 10.1186/1754-1611-7-29] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 11/12/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Standardized and well-characterized genetic building blocks are a prerequisite for the convenient and reproducible assembly of novel genetic modules and devices. While numerous standardized parts exist for Escherichia coli, such tools are still missing for the Gram-positive model organism Bacillus subtilis. The goal of this study was to develop and thoroughly evaluate such a genetic toolbox. RESULTS We developed five BioBrick-compatible integrative B. subtilis vectors by deleting unnecessary parts and removing forbidden restriction sites to allow cloning in BioBrick (RFC10) standard. Three empty backbone vectors with compatible resistance markers and integration sites were generated, allowing the stable chromosomal integration and combination of up to three different devices in one strain. In addition, two integrative reporter vectors, based on the lacZ and luxABCDE cassettes, were BioBrick-adjusted, to enable β-galactosidase and luciferase reporter assays, respectively. Four constitutive and two inducible promoters were thoroughly characterized by quantitative, time-resolved measurements. Together, these promoters cover a range of more than three orders of magnitude in promoter strength, thereby allowing a fine-tuned adjustment of cellular protein amounts. Finally, the Bacillus BioBrick Box also provides five widely used epitope tags (FLAG, His10, cMyc, HA, StrepII), which can be translationally fused N- or C-terminally to any protein of choice. CONCLUSION Our genetic toolbox contains three compatible empty integration vectors, two reporter vectors and a set of six promoters, two of them inducible. Furthermore, five different epitope tags offer convenient protein handling and detection. All parts adhere to the BioBrick standard and hence enable standardized work with B. subtilis. We believe that our well-documented and carefully evaluated Bacillus BioBrick Box represents a very useful genetic tool kit, not only for the iGEM competition but any other BioBrick-based project in B. subtilis.
Collapse
Affiliation(s)
- Jara Radeck
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Korinna Kraft
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Julia Bartels
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Tamara Cikovic
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Franziska Dürr
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Jennifer Emenegger
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Simon Kelterborn
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Christopher Sauer
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany.,Present affiliation: Institute of Cell and Molecular Biosciences, Newcastle University, Centre for Bacterial Cell Biology, Richardson Road, NE2 4AX Newcastle upon Tyne, UK
| | - Georg Fritz
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany.,Ludwig-Maximilians-University Munich, Arnold Sommerfeld Center for Theoretical Physics, Theresienstr. 37, D-80333 München, Germany
| | - Susanne Gebhard
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Thorsten Mascher
- Department Biology I, AG Synthetic Microbiology, Ludwig-Maximilians-Universität München, Grosshaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| |
Collapse
|
16
|
Gunka K, Stannek L, Care RA, Commichau FM. Selection-driven accumulation of suppressor mutants in bacillus subtilis: the apparent high mutation frequency of the cryptic gudB gene and the rapid clonal expansion of gudB(+) suppressors are due to growth under selection. PLoS One 2013; 8:e66120. [PMID: 23785476 PMCID: PMC3681913 DOI: 10.1371/journal.pone.0066120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/01/2013] [Indexed: 11/25/2022] Open
Abstract
Soil bacteria like Bacillus subtilis can cope with many growth conditions by adjusting gene expression and metabolic pathways. Alternatively, bacteria can spontaneously accumulate beneficial mutations or shape their genomes in response to stress. Recently, it has been observed that a B. subtilis mutant lacking the catabolically active glutamate dehydrogenase (GDH), RocG, mutates the cryptic gudBCR gene at a high frequency. The suppressor mutants express the active GDH GudB, which can fully replace the function of RocG. Interestingly, the cryptic gudBCR allele is stably inherited as long as the bacteria synthesize the functional GDH RocG. Competition experiments revealed that the presence of the cryptic gudBCR allele provides the bacteria with a selective growth advantage when glutamate is scarce. Moreover, the lack of exogenous glutamate is the driving force for the selection of mutants that have inactivated the active gudB gene. In contrast, two functional GDHs are beneficial for the cells when glutamate was available. Thus, the amount of GDH activity strongly affects fitness of the bacteria depending on the availability of exogenous glutamate. At a first glance the high mutation frequency of the cryptic gudBCR allele might be attributed to stress-induced adaptive mutagenesis. However, other loci on the chromosome that could be potentially mutated during growth under the selective pressure that is exerted on a GDH-deficient mutant remained unaffected. Moreover, we show that a GDH-proficient B. subtilis strain has a strong selective growth advantage in a glutamate-dependent manner. Thus, the emergence and rapid clonal expansion of the active gudB allele can be in fact explained by spontaneous mutation and growth under selection without an increase of the mutation rate. Moreover, this study shows that the selective pressure that is exerted on a maladapted bacterium strongly affects the apparent mutation frequency of mutational hot spots.
Collapse
Affiliation(s)
- Katrin Gunka
- Department of General Microbiology, Georg-August-University Göttingen, Göttingen, Germany
| | - Lorena Stannek
- Department of General Microbiology, Georg-August-University Göttingen, Göttingen, Germany
| | - Rachel A. Care
- Department of General Microbiology, Georg-August-University Göttingen, Göttingen, Germany
| | - Fabian M. Commichau
- Department of General Microbiology, Georg-August-University Göttingen, Göttingen, Germany
- * E-mail:
| |
Collapse
|
17
|
Immediate and heterogeneous response of the LiaFSR two-component system of Bacillus subtilis to the peptide antibiotic bacitracin. PLoS One 2013; 8:e53457. [PMID: 23326432 PMCID: PMC3543457 DOI: 10.1371/journal.pone.0053457] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/30/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Two-component signal transduction systems are one means of bacteria to respond to external stimuli. The LiaFSR two-component system of Bacillus subtilis consists of a regular two-component system LiaRS comprising the core Histidine Kinase (HK) LiaS and the Response Regulator (RR) LiaR and additionally the accessory protein LiaF, which acts as a negative regulator of LiaRS-dependent signal transduction. The complete LiaFSR system was shown to respond to various peptide antibiotics interfering with cell wall biosynthesis, including bacitracin. METHODOLOGY AND PRINCIPAL FINDINGS Here we study the response of the LiaFSR system to various concentrations of the peptide antibiotic bacitracin. Using quantitative fluorescence microscopy, we performed a whole population study analyzed on the single cell level. We investigated switching from the non-induced 'OFF' state into the bacitracin-induced 'ON' state by monitoring gene expression of a fluorescent reporter from the RR-regulated liaI promoter. We found that switching into the 'ON' state occurred within less than 20 min in a well-defined switching window, independent of the bacitracin concentration. The switching rate and the basal expression rate decreased at low bacitracin concentrations, establishing clear heterogeneity 60 min after bacitracin induction. Finally, we performed time-lapse microscopy of single cells confirming the quantitative response as obtained in the whole population analysis for high bacitracin concentrations. CONCLUSION The LiaFSR system exhibits an immediate, heterogeneous and graded response to the inducer bacitracin in the exponential growth phase.
Collapse
|
18
|
Botella E, Noone D, Salzberg LI, Hokamp K, Devine SK, Fogg M, Wilkinson AJ, Devine KM. High-resolution temporal analysis of global promoter activity in Bacillus subtilis. METHODS IN MICROBIOLOGY 2012. [DOI: 10.1016/b978-0-08-099387-4.00001-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
19
|
Fluorescent proteins in microbial biotechnology—new proteins and new applications. Biotechnol Lett 2011; 34:175-86. [DOI: 10.1007/s10529-011-0767-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 09/29/2011] [Indexed: 10/17/2022]
|
20
|
Bisicchia P, Bui NK, Aldridge C, Vollmer W, Devine KM. Acquisition of VanB-type vancomycin resistance by Bacillus subtilis: the impact on gene expression, cell wall composition and morphology. Mol Microbiol 2011; 81:157-78. [PMID: 21542863 DOI: 10.1111/j.1365-2958.2011.07684.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The vancomycin resistance operons from Enterococci, Staphylococci and Actinomycetes encode a VanRS two-component signal transduction system (TCS) and a suite of enzymes to modify the peptidoglycan biosynthetic precursor lipid II and to eliminate the D-Ala-D-Ala from the cell. Commingling of these regulatory and enzymatic activities with host functions has the potential to significantly impact host gene expression and cell wall metabolism. Here we report the effects of individually expressing the VanR(B) S(B) TCS and the VanY(B) WH(B) BX(B) resistance proteins in Bacillus subtilis. VanY(B) WH(B) BX(B) expression confers resistance to 2 µg ml(-1) of vancomycin with concomitant reduced Van-FL staining and leads to a cell division defect. In contrast to E. faecalis and S. aureus, VanS(B) is active in B. subtilis without vancomycin addition. Individual expression of the VanR(B) S(B) TCS and the VanY(B) WH(B) BX(B) resistance proteins repress and increase, respectively, expression of PhoPR regulon genes in the phosphate-limited state. When vancomycin-resistant cells are exposed to elevated vancomycin levels, mutant strains with increased resistance to vancomycin and a growth dependency on vanY(B) WH(B) BX(B) expression frequently arise. Mutation of the endogenous Ddl ligase is the necessary and sufficient cause of both phenotypes. We discuss how these effects may influence establishment of van operons in new host bacteria.
Collapse
Affiliation(s)
- Paola Bisicchia
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | | | | | | | | |
Collapse
|