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Huijboom L, Tempelaars M, Fan M, Zhu Y, Boeren S, van der Linden E, Abee T. l-tyrosine modulates biofilm formation of Bacillus cereus ATCC 14579. Res Microbiol 2023; 174:104072. [PMID: 37080258 DOI: 10.1016/j.resmic.2023.104072] [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] [Received: 10/22/2022] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/22/2023]
Abstract
Bacillus cereus is a food-borne pathogen capable of producing biofilms. Following analysis of biofilm formation by B. cereus ATCC 14579 transposon mutants in defined medium (DM), a deletion mutant of bc2939 (Δbc2939) was constructed that showed decreased crystal violet biofilm staining and biofilm cell counts. In addition, Δbc2939 also produced smaller colony biofilms with lower cell counts and loss of wrinkly morphology. The bc2939 gene encodes for Prephenate dehydrogenase, which converts Prephenate to 4-Hydroxy-phenylpyruvate (4-HPPA) in the l-tyrosine branch of the Shikimate pathway. While growth of the mutant and WT in DM was similar, addition of l-tyrosine was required to restore WT-like (colony) biofilm formation. Comparative proteomics showed reduced expression of Tyrosine-protein kinase/phosphatase regulators and extracellular polysaccharide cluster 1 (EPS1) proteins, aerobic electron transfer chain cytochrome aa3/d quinol oxidases, and iso-chorismate synthase involved in menaquinone synthesis in DM grown mutant biofilm cells, while multiple oxidative stress-related catalases and superoxide dismutases were upregulated. Performance in shaking cultures showed a 100-fold lower concentration of menaquinone-7 and reduction in cell counts of DM grown Δbc2939 indicating increased oxygen sensitivity. Combining all results, points to an important role of Tyrosine-modulated EPS1 production and menaquinone-dependent aerobic respiration in B. cereus ATCC 14579 (colony) biofilm formation.
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Affiliation(s)
- Linda Huijboom
- Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
| | - Marcel Tempelaars
- Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
| | - Mingzhen Fan
- Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
| | - Yourong Zhu
- Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, Wageningen, 6708, WE, the Netherlands.
| | - Erik van der Linden
- Laboratory of Physics and Physical Chemistry of Foods, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
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Abstract
The DNA-binding protein from starved cells, Dps, is a universally conserved prokaryotic ferritin that, in many species, also binds DNA. Dps homologs have been identified in the vast majority of bacterial species and several archaea. Dps also may play a role in the global regulation of gene expression, likely through chromatin reorganization. Dps has been shown to use both its ferritin and DNA-binding functions to respond to a variety of environmental pressures, including oxidative stress. One mechanism that allows Dps to achieve this is through a global nucleoid restructuring event during stationary phase, resulting in a compact, hexacrystalline nucleoprotein complex called the biocrystal that occludes damaging agents from DNA. Due to its small size, hollow spherical structure, and high stability, Dps is being developed for applications in biotechnology.
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SigB regulates stress resistance, glucose starvation, MnSOD production, biofilm formation, and root colonization in Bacillus cereus 905. Appl Microbiol Biotechnol 2021; 105:5943-5957. [PMID: 34350477 DOI: 10.1007/s00253-021-11402-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/25/2021] [Accepted: 05/29/2021] [Indexed: 10/20/2022]
Abstract
Bacillus cereus 905, originally isolated from wheat rhizosphere, exhibits strong colonization ability on wheat roots. Our previous studies showed that root colonization is contributed by the ability of the bacterium to efficiently utilize carbon sources and form biofilms and that the sodA2 gene-encoded manganese-containing superoxide dismutase (MnSOD2) plays an indispensable role in the survival of B. cereus 905 in the wheat rhizosphere. In this investigation, we further demonstrated that the ability of B. cereus 905 to resist adverse environmental conditions is partially attributed to activation of the alternative sigma factor σB, encoded by the sigB gene. The sigB mutant experienced a dramatic reduction in survival when cells were exposed to ethanol, acid, heat, and oxidative stress or under glucose starvation. Analysis of the sodA2 gene transcription revealed a partial, σB-dependent induction of the gene during glucose starvation or when treated with paraquat. In addition, the sigB mutant displayed a defect in biofilm formation under stress conditions. Finally, results from the root colonization assay indicated that sigB and sodA2 collectively contribute to B. cereus 905 colonization on wheat roots. Our study suggests a diverse role of SigB in rhizosphere survival and root colonization of B. cereus 905 under stress conditions. KEY POINTS : • SigB confers resistance to environmental stresses in B. cereus 905. • SigB plays a positive role in glucose utilization and biofilm formation in B. cereus. • SigB and SodA2 collectively contribute to colonization on wheat roots by B. cereus.
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Tirumalai MR, Stepanov VG, Wünsche A, Montazari S, Gonzalez RO, Venkateswaran K, Fox GE. Bacillus safensis FO-36b and Bacillus pumilus SAFR-032: a whole genome comparison of two spacecraft assembly facility isolates. BMC Microbiol 2018; 18:57. [PMID: 29884123 PMCID: PMC5994023 DOI: 10.1186/s12866-018-1191-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/18/2018] [Indexed: 11/16/2022] Open
Abstract
Background Bacillus strains producing highly resistant spores have been isolated from cleanrooms and space craft assembly facilities. Organisms that can survive such conditions merit planetary protection concern and if that resistance can be transferred to other organisms, a health concern too. To further efforts to understand these resistances, the complete genome of Bacillus safensis strain FO-36b, which produces spores resistant to peroxide and radiation was determined. The genome was compared to the complete genome of B. pumilus SAFR-032, and the draft genomes of B. safensis JPL-MERTA-8-2 and the type strain B. pumilus ATCC7061T. Additional comparisons were made to 61 draft genomes that have been mostly identified as strains of B. pumilus or B. safensis. Results The FO-36b gene order is essentially the same as that in SAFR-032 and other B. pumilus strains. The annotated genome has 3850 open reading frames and 40 noncoding RNAs and riboswitches. Of these, 307 are not shared by SAFR-032, and 65 are also not shared by MERTA and ATCC7061T. The FO-36b genome has ten unique open reading frames and two phage-like regions, homologous to the Bacillus bacteriophage SPP1 and Brevibacillus phage Jimmer1. Differing remnants of the Jimmer1 phage are found in essentially all B. safensis / B. pumilus strains. Seven unique genes are part of these phage elements. Whole Genome Phylogenetic Analysis of the B. pumilus, B. safensis and other Firmicutes genomes, separate them into three distinct clusters. Two clusters are subgroups of B. pumilus while one houses all the B. safensis strains. The Genome-genome distance analysis and a phylogenetic analysis of gyrA sequences corroborated these results. Conclusions It is not immediately obvious that the presence or absence of any specific gene or combination of genes is responsible for the variations in resistance seen. It is quite possible that distinctions in gene regulation can alter the expression levels of key proteins thereby changing the organism’s resistance properties without gain or loss of a particular gene. What is clear is that phage elements contribute significantly to genome variability. Multiple genome comparison indicates that many strains named as B. pumilus likely belong to the B. safensis group. Electronic supplementary material The online version of this article (10.1186/s12866-018-1191-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Madhan R Tirumalai
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Victor G Stepanov
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Andrea Wünsche
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Saied Montazari
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Racquel O Gonzalez
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Kasturi Venkateswaran
- Biotechnology & Planetary Protection Group, NASA Jet Propulsion Laboratories, California Institute of Technology, Pasadena, CA, 91109, USA
| | - George E Fox
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA.
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Chen JC, Chang CF, Hsu DW, Shu JC, Chen HY, Chen CY, Lu CY, Chen CC. Temporal regulation of σ B by partner-switching mechanism at a distinct growth stage in Bacillus cereus. Int J Med Microbiol 2017; 307:521-532. [PMID: 28919098 DOI: 10.1016/j.ijmm.2017.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/15/2017] [Accepted: 09/04/2017] [Indexed: 12/01/2022] Open
Abstract
The alternative transcription factor σB in Bacillus cereus governs the transcription of a number of genes that confer protection against general stress. This transcription factor is regulated by protein-protein interactions among RsbV, RsbW, σB, RsbY, RsbM and RsbK, all encoded in the sigB cluster. Among these regulatory proteins, RsbV, RsbW and σB comprise a partner-switching mechanism. Under normal conditions, σB remains inactive by associating with anti-sigma factor RsbW, which prevents σB from binding to the core RNA polymerase. During environmental stress, RsbK activates RsbY to hydrolyze phosphorylated RsbV, and the dephosphorylated RsbV then sequesters RsbW to liberate σB from RsbW. Although the σB partner-switching module is thought to be the core mechanism for σB regulation, the actual protein-protein interactions among these three proteins in the cell remain to be investigated. In the current study, we show that RsbW and RsbV form a long-lived complex under transient stress treatment, resulting in high persistent expression of RsbV, RsbW and σB from mid-log phase to stationary phase. Full sequestration of RsbW by excess RsbV and increased RsbW:RsbV complex stability afforded by cellular ADP contribute to the prolonged activation of σB. Interestingly, the high expression levels of RsbV, RsbW and σB were dramatically decreased beginning from the transition stage to the stationary phase. Thus, protein interactions among σB partner-switching components are required for the continued induction of σB during environmental stress in the log phase and significant down-regulation of σB is observed in the stationary phase. Our data show that σB is temporally regulated in B. cereus.
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Affiliation(s)
- Jung-Chi Chen
- Department of Biotechnology, National Kaohsiung Normal University, 62 Shenjhong Road, Yanchao District, Kaohsiung 82444, Taiwan
| | - Chuan-Fu Chang
- Department of Biotechnology, National Kaohsiung Normal University, 62 Shenjhong Road, Yanchao District, Kaohsiung 82444, Taiwan
| | - Duen-Wei Hsu
- Department of Biotechnology, National Kaohsiung Normal University, 62 Shenjhong Road, Yanchao District, Kaohsiung 82444, Taiwan
| | - Jwu-Ching Shu
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan County 333, Taiwan
| | - Hong-Yi Chen
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan County 333, Taiwan
| | - Chien-Yen Chen
- Department of Earth and Environmental Sciences, National Chung Cheng University, 168 University Road, Min-Hsiung, Chiayi 62102, Taiwan
| | - Chi-Yu Lu
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Chien-Cheng Chen
- Department of Biotechnology, National Kaohsiung Normal University, 62 Shenjhong Road, Yanchao District, Kaohsiung 82444, Taiwan.
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Volpicella M, Leoni C, Manzari C, Chiara M, Picardi E, Piancone E, Italiano F, D'Erchia A, Trotta M, Horner DS, Pesole G, Ceci LR. Transcriptomic analysis of nickel exposure in Sphingobium sp. ba1 cells using RNA-seq. Sci Rep 2017; 7:8262. [PMID: 28811613 PMCID: PMC5557971 DOI: 10.1038/s41598-017-08934-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/10/2017] [Indexed: 02/06/2023] Open
Abstract
Nickel acts as cofactor for a number of enzymes of many bacteria species. Its homeostasis is ensured by proteins working as ion efflux or accumulation systems. These mechanisms are also generally adopted to counteract life-threatening high extra-cellular Ni2+ concentrations. Little is known regarding nickel tolerance in the genus Sphingobium. We studied the response of the novel Sphingobium sp. ba1 strain, able to adapt to high Ni2+ concentrations. Differential gene expression in cells cultured in 10 mM Ni2+, investigated by RNA-seq analysis, identified 118 differentially expressed genes. Among the 90 up-regulated genes, a cluster including genes coding for nickel and other metal ion efflux systems (similar to either cnrCBA, nccCBA or cznABC) and for a NreB-like permease was found. Comparative analyses among thirty genomes of Sphingobium species show that this cluster is conserved only in two cases, while in the other genomes it is partially present or even absent. The differential expression of genes encoding proteins which could also work as Ni2+-accumulators (HupE/UreJ-like protein, NreA and components of TonB-associated transport and copper-homeostasis systems) was also detected. The identification of Sphingobium sp. ba1 strain adaptive mechanisms to nickel ions, can foster its possible use for biodegradation of poly-aromatic compounds in metal-rich environments.
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Affiliation(s)
- M Volpicella
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - C Leoni
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - C Manzari
- IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - M Chiara
- Department of Biosciences, University of Milan, Milan, Italy
| | - E Picardi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - E Piancone
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - F Italiano
- IPCF-CNR, Institute for Chemical-Physical Processes, Bari, Italy
| | - A D'Erchia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - M Trotta
- IPCF-CNR, Institute for Chemical-Physical Processes, Bari, Italy
| | - D S Horner
- IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy.,Department of Biosciences, University of Milan, Milan, Italy
| | - G Pesole
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - L R Ceci
- IBIOM-CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy.
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Shu JC, Soo PC, Chen JC, Hsu SH, Chen LC, Chen CY, Liang SH, Buu LM, Chen CC. Differential regulation and activity against oxidative stress of Dps proteins in Bacillus cereus. Int J Med Microbiol 2013; 303:662-73. [DOI: 10.1016/j.ijmm.2013.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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8
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Desriac N, Broussolle V, Postollec F, Mathot AG, Sohier D, Coroller L, Leguerinel I. Bacillus cereus cell response upon exposure to acid environment: toward the identification of potential biomarkers. Front Microbiol 2013; 4:284. [PMID: 24106490 PMCID: PMC3788345 DOI: 10.3389/fmicb.2013.00284] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/03/2013] [Indexed: 01/20/2023] Open
Abstract
Microorganisms are able to adapt to different environments and evolve rapidly, allowing them to cope with their new environments. Such adaptive response and associated protections toward other lethal stresses, is a crucial survival strategy for a wide spectrum of microorganisms, including food spoilage bacteria, pathogens, and organisms used in functional food applications. The growing demand for minimal processed food yields to an increasing use of combination of hurdles or mild preservation factors in the food industry. A commonly used hurdle is low pH which allows the decrease in bacterial growth rate but also the inactivation of pathogens or spoilage microorganisms. Bacillus cereus is a well-known food-borne pathogen leading to economical and safety issues in food industry. Because survival mechanisms implemented will allow bacteria to cope with environmental changes, it is important to provide understanding of B. cereus stress response. Thus this review deals with the adaptive traits of B. cereus cells facing to acid stress conditions. The acid stress response of B. cereus could be divided into four groups (i) general stress response (ii) pH homeostasis, (iii) metabolic modifications and alkali production and (iv) secondary oxidative stress response. This current knowledge may be useful to understand how B. cereus cells may cope to acid environment such as encountered in food products and thus to find some molecular biomarkers of the bacterial behavior. These biomarkers could be furthermore used to develop new microbial behavior prediction tools which can provide insights into underlying molecular physiological states which govern the behavior of microorganisms and thus opening the avenue toward the detection of stress adaptive behavior at an early stage and the control of stress-induced resistance throughout the food chain.
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Affiliation(s)
- Noémie Desriac
- ADRIA Développement, UMT 08.3 PHYSI’Opt, QuimperFrance
- EA3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT 08.3 PHYSI’Opt, IFR148 ScInBioS, Université de BrestQuimper, France
| | - Véronique Broussolle
- UMR408, Sécurité et Qualité des Produits d’Origine Végétale, Institut National de la Recherche AgronomiqueAvignon, France
- UMR408, Sécurité et Qualité des Produits d’Origine Végétale, Université d’Avignon et des Pays de VaucluseAvignon, France
| | | | - Anne-Gabrielle Mathot
- EA3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT 08.3 PHYSI’Opt, IFR148 ScInBioS, Université de BrestQuimper, France
| | | | - Louis Coroller
- EA3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT 08.3 PHYSI’Opt, IFR148 ScInBioS, Université de BrestQuimper, France
| | - Ivan Leguerinel
- EA3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT 08.3 PHYSI’Opt, IFR148 ScInBioS, Université de BrestQuimper, France
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9
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Chen LC, Chen JC, Shu JC, Chen CY, Chen SC, Chen SH, Lin CY, Lu CY, Chen CC. Interplay of RsbM and RsbK controls the σ(B) activity of Bacillus cereus. Environ Microbiol 2012; 14:2788-99. [PMID: 22640257 DOI: 10.1111/j.1462-2920.2012.02788.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The alternative transcription factor σ(B) of Bacillus cereus controls the expression of a number of genes that respond to environmental stress. Four proteins encoded in the sigB gene cluster, including RsbV, RsbW, RsbY (RsbU) and RsbK, are known to be essential in the σ(B)-mediated stress response. In the context of stress, the hybrid sensor kinase RsbK is thought to phosphorylate the response regulator RsbY, a PP2C serine phosphatase, leading to the dephosphorylation of the phosphorylated RsbV. The unphosphorylated RsbV then sequesters the σ(B) antagonist, RsbW, ultimately liberating σ(B). The gene arrangement reveals an open reading frame, bc1007, flanked immediately downstream by rsbK within the sigB gene cluster. However, little is known about the function of bc1007. In this study, the deletion of bc1007 resulted in high constitutive σ(B) expression independent of environmental stimuli, indicating that bc1007 plays a role in σ(B) regulation. A bacterial two-hybrid analysis demonstrated that BC1007 interacts directly with RsbK, and autoradiographic studies revealed a specific C(14)-methyl transfer from the radiolabelled S-adenosylmethionine to RsbK when RsbK was incubated with purified BC1007. Our data suggest that BC1007 (RsbM) negatively regulates σ(B) activity by methylating RsbK. Additionally, mutagenic substitution was employed to modify 12 predicted methylation residues in RsbK. Certain RsbK mutants were able to rescue σ(B) activation in a rsbK-deleted bacterial strain, but RsbK(E439A) failed to activate σ(B), and RsbK(E446A) only moderately induced σ(B). These results suggest that Glu439 is the preferred methylation site and that Glu446 is potentially a minor methylation site. Gene arrays of the rsbK orthologues and the neighbouring rsbM orthologues are found in a wide range of bacteria. The regulation of sigma factors through metylation of RsbK-like sensor kinases appears to be widespread in the microbial world.
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Affiliation(s)
- Lei-Chin Chen
- Department of Nutrition, I-Shou University, Jiaosu Village, Yanchao District, Kaohsiung 82445, Taiwan
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Pesek J, Büchler R, Albrecht R, Boland W, Zeth K. Structure and mechanism of iron translocation by a Dps protein from Microbacterium arborescens. J Biol Chem 2011; 286:34872-82. [PMID: 21768097 PMCID: PMC3186433 DOI: 10.1074/jbc.m111.246108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dps (DNA protection during starvation) enzymes are a major class of dodecameric proteins that bacteria use to detoxify their cytosol through the uptake of reactive iron species. In the stationary growth phase of bacteria, Dps enzymes are primarily used to protect DNA by biocrystallization. To characterize the wild type Dps protein from Microbacterium arborescens that displays additional catalytic functions (amide hydrolysis and synthesis), we determined the crystal structure to a resolution of 2.05 Å at low iron content. The structure shows a single iron at the ferroxidase center coordinated by an oxo atom, one water molecule, and three ligating residues. An iron-enriched protein structure was obtained at 2 Å and shows the stepwise uptake of two hexahydrated iron atoms moving along channels at the 3-fold axis before a restriction site inside the channels requires removal of the hydration sphere. Supporting biochemical data provide insight into the regulation of this acylamino acid hydrolase. Moreover, the peroxidase activity of the protein was determined. The influence of iron and siderophores on the expression of acylamino acid hydrolase was monitored during several stages of cell growth. Altogether our data provide an interesting view of an unusual Dps-like enzyme evolutionarily located apart from the large Dps sequence clusters.
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Affiliation(s)
- Jelena Pesek
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany
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Ševců A, El-Temsah YS, Joner EJ, Černík M. Oxidative Stress Induced in Microorganisms by Zero-valent Iron Nanoparticles. Microbes Environ 2011; 26:271-81. [DOI: 10.1264/jsme2.me11126] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Alena Ševců
- Institute for Nanomaterials, Advanced Technologies and Innovations, Technical University of Liberec
| | | | | | - Miroslav Černík
- Institute for Nanomaterials, Advanced Technologies and Innovations, Technical University of Liberec
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12
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de Been M, Tempelaars MH, van Schaik W, Moezelaar R, Siezen RJ, Abee T. A novel hybrid kinase is essential for regulating the sigma(B)-mediated stress response of Bacillus cereus. Environ Microbiol 2009; 12:730-45. [PMID: 19958380 DOI: 10.1111/j.1462-2920.2009.02116.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A common bacterial strategy for monitoring environmental challenges is to use two-component systems, which consist of a sensor histidine kinase (HK) and a response regulator (RR). In the food-borne pathogen Bacillus cereus, the alternative sigma factor sigma(B) is activated by the RR RsbY. Here we present strong indications that the PP2C-type phosphatase RsbY receives its input from the multi-sensor hybrid kinase BC1008 (renamed RsbK). Genome analyses revealed that, across bacilli, rsbY and rsbK are located in a conserved gene cluster. A B. cereus rsbK deletion strain was shown to be incapable of inducing sigma(B) upon stress conditions and was impaired in its heat adaptive response. Comparison of the wild-type and rsbK mutant transcriptomes upon heat shock revealed that RsbK was primarily involved in the activation of the sigma(B)-mediated stress response. Truncation of the RsbK RR receiver domain demonstrated the importance of this domain for sigma(B) induction upon stress. The domain architecture of RsbK suggests that in the B. cereus group and in other bacilli, environmental and intracellular stress signalling routes are combined into one single protein. This strategy is markedly different from the sigma(B) activation pathway in other low-GC Gram-positives.
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Affiliation(s)
- Mark de Been
- TI Food and Nutrition (TIFN), Wageningen, the Netherlands.
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