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Baev V, Iliev I, Stefanov Y, Tsankova M, Marhova M, Apostolova E, Gozmanova M, Yahubyan G, Kostadinova S. Exploring the Genomic Landscape of Bacillus paranthracis PUMB_17 as a Proficient Phosphatidylcholine-Specific Phospholipase C Producer. Curr Issues Mol Biol 2024; 46:2497-2513. [PMID: 38534774 DOI: 10.3390/cimb46030158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
Phospholipases find versatile applications across industries, including detergent production, food modification, pharmaceuticals (especially in drug delivery systems), and cell signaling research. In this study, we present a strain of Bacillus paranthracis for the first time, demonstrating significant potential in the production of phosphatidylcholine-specific phospholipase C (PC-PLC). The investigation thoroughly examines the B. paranthracis PUMB_17 strain, focusing on the activity of PC-PLC and its purification process. Notably, the PUMB_17 strain displays extracellular PC-PLC production with high specific activity during the late exponential growth phase. To unravel the genetic makeup of PUMB_17, we employed nanopore-based whole-genome sequencing and subsequently conducted a detailed genome annotation. The genome comprises a solitary circular chromosome spanning 5,250,970 bp, featuring a guanine-cytosine ratio of 35.49. Additionally, two plasmids of sizes 64,250 bp and 5845 bp were identified. The annotation analysis reveals the presence of 5328 genes, encompassing 5186 protein-coding sequences, and 142 RNA genes, including 39 rRNAs, 103 tRNAs, and 5 ncRNAs. The aim of this study was to make a comprehensive genomic exploration that promises to enhance our understanding of the previously understudied and recently documented capabilities of Bacillus paranthracis and to shed light on a potential use of the strain in the industrial production of PC-PLC.
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Affiliation(s)
- Vesselin Baev
- Department of Molecular Biology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Ivan Iliev
- Department of Biochemistry and Microbiology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | | | - Marinela Tsankova
- Department of Biochemistry and Microbiology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Mariana Marhova
- Department of Biochemistry and Microbiology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Elena Apostolova
- Department of Molecular Biology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Mariyana Gozmanova
- Department of Molecular Biology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Galina Yahubyan
- Department of Molecular Biology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
| | - Sonya Kostadinova
- Department of Biochemistry and Microbiology, Faculty of Biology, University of Plovdiv, Tzar Assen 24, 4000 Plovdiv, Bulgaria
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Sun Y, Shuai W, Nie L, Li X, Jiang L. Investigating the Role of OrbF in Biofilm Biosynthesis and Regulation of Biofilm-Associated Genes in Bacillus cereus BC1. Foods 2024; 13:638. [PMID: 38472751 DOI: 10.3390/foods13050638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 03/14/2024] Open
Abstract
Bacillus cereus (B. cereus), a prevalent foodborne pathogen, constitutes a substantial risk to food safety due to its pronounced resilience under adverse environmental conditions such as elevated temperatures and ultraviolet radiation. This resilience can be attributed to its capacity for biofilm synthesis and sustained high viability. Our research aimed to elucidate the mechanisms governing biofilm biosynthesis in B. cereus. To this end, we constructed a 5088-mutant library of the B. cereus strain BC1 utilizing the transposon TnYLB-1. Systematic screening of this library yielded mutants exhibiting diminished biofilm formation capabilities. Twenty-four genes associated with the biofilm synthesis were identified by reverse PCR in these mutants, notably revealing a significant reduction in biofilm synthesis upon disruption of the orbF gene in B. cereus BC1. Comparative analysis between the wild type and orbF-deficient BC1 strains (BC1ΔorbF) indicated a marked downregulation (decreased by 11.7% to 96.7%) in the expression of genes implicated in biofilm formation, flagellar assembly, and bacterial chemotaxis in the BC1ΔorbF. Electrophoretic mobility shift assay (EMSA) further corroborated the role of OrbF, demonstrating its binding to the promoter region of the biofilm gene cluster, subsequently leading to the suppression of transcriptional activity of biofilm-associated genes in B. cereus BC1. Our findings underscore the pivotal role of orbF in biofilm biosynthesis in B. cereus, highlighting its potential as a target for strategies aimed at mitigating biofilm formation in this pathogen.
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Affiliation(s)
- Yang Sun
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Wenjing Shuai
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Lanmengya Nie
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Xiangfei Li
- Engineering Laboratory for Industrial Microbiology Molecular Beeding of Anhui Province, College of Biologic & Food Engineering, Anhui Polytechnic University, 8 Middle Beijing Road, Wuhu 241000, China
| | - Ling Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
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Hu G, Wang Y, Liu X, Strube ML, Wang B, Kovács ÁT. Species and condition shape the mutational spectrum in experimentally evolved biofilms. mSystems 2023; 8:e0054823. [PMID: 37768063 PMCID: PMC10654089 DOI: 10.1128/msystems.00548-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 08/11/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE Biofilm formation is a vital factor for the survival and adaptation of bacteria in diverse environmental niches. Experimental evolution combined with the advancement of whole-population genome sequencing provides us a powerful tool to understand the genomic dynamic of evolutionary adaptation to different environments, such as during biofilm development. Previous studies described the genetic and phenotypic changes of selected clones from experimentally evolved Bacillus thuringiensis and Bacillus subtilis that were adapted under abiotic and biotic biofilm conditions. However, the full understanding of the dynamic evolutionary landscapes was lacking. Furthermore, the differences and similarities of adaptive mechanisms in B. thuringiensis and B. subtilis were not identified. To overcome these limitations, we performed longitudinal whole-population genome sequencing to study the underlying genetic dynamics at high resolution. Our study provides the first comprehensive mutational landscape of two bacterial species' biofilms that is adapted to an abiotic and biotic surface.
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Affiliation(s)
- Guohai Hu
- China National GeneBank, BGI, Shenzhen, China
- BGI Research, Shenzhen, China
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Yue Wang
- China National GeneBank, BGI, Shenzhen, China
- BGI Research, Shenzhen, China
- BGI Research, Beijing, China
| | - Xin Liu
- China National GeneBank, BGI, Shenzhen, China
- BGI Research, Shenzhen, China
- BGI Research, Beijing, China
| | - Mikael Lenz Strube
- Bacterial Ecophysiology and Biotechnology Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Bo Wang
- China National GeneBank, BGI, Shenzhen, China
- BGI Research, Shenzhen, China
- Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI Research, Shenzhen, China
| | - Ákos T. Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
- Institute of Biology, Leiden University, Leiden, The Netherlands
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4
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Yehuda A, Malach E, Vanunu Ofri S, Slamti L, Kuo SH, Lau JZ, Oh MW, Adeoye J, Shlezinger N, Lereclus D, Lau GW, Hayouka Z. The quorum-sensing peptidic inhibitor rescues host immune system eradication: A novel infectivity mechanism. Proc Natl Acad Sci U S A 2023; 120:e2301045120. [PMID: 37607229 PMCID: PMC10469338 DOI: 10.1073/pnas.2301045120] [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: 01/19/2023] [Accepted: 06/23/2023] [Indexed: 08/24/2023] Open
Abstract
Subverting the host immune system is a major task for any given pathogen to assure its survival and proliferation. For the opportunistic human pathogen Bacillus cereus (Bc), immune evasion enables the establishment of potent infections. In various species of the Bc group, the pleiotropic regulator PlcR and its cognate cell-cell signaling peptide PapR7 regulate virulence gene expression in response to fluctuations in population density, i.e., a quorum-sensing (QS) system. However, how QS exerts its effects during infections and whether PlcR confers the immune evading ability remain unclear. Herein, we report how interception of the QS communication in Bc obliterates the ability to affect the host immune system. Here, we designed a peptide-based QS inhibitor that suppresses PlcR-dependent virulence factor expression and attenuates Bc infectivity in mouse models. We demonstrate that the QS peptidic inhibitor blocks host immune system-mediated eradication by reducing the expression of PlcR-regulated major toxins similarly to the profile that was observed for isogenic strains. Our findings provide evidence that Bc infectivity is regulated by QS circuit-mediated destruction of host immunity, thus reveal a interesting strategy to limit Bc virulence and enhance host defense. This peptidic quorum-quenching agent constitutes a readily accessible chemical tool for studying how other pathogen QS systems modulate host immunity and forms a basis for development of anti-infective therapeutics.
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Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Einav Malach
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Shahar Vanunu Ofri
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Leyla Slamti
- Unité Micalis, Domaine de La Minière, Unité Mixte de Recherche 1319, Institut National de la Recherche Agronomique, 78280Guyancourt, France
| | - Shanny Hsuan Kuo
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Jonathan Z. Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Myung Whan Oh
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - John Adeoye
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Neta Shlezinger
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Didier Lereclus
- Unité Micalis, Domaine de La Minière, Unité Mixte de Recherche 1319, Institut National de la Recherche Agronomique, 78280Guyancourt, France
| | - Gee W. Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
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Toukabri H, Lereclus D, Slamti L. A Sporulation-Independent Way of Life for Bacillus thuringiensis in the Late Stages of an Infection. mBio 2023:e0037123. [PMID: 37129506 DOI: 10.1128/mbio.00371-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
The formation of endospores has been considered the unique survival and transmission mode of sporulating Firmicutes due to the exceptional resistance and persistence of this bacterial form. However, nonsporulated bacteria (Spo-) were reported at the early stages following the death of a host infected with Bacillus thuringiensis, an entomopathogenic sporulating bacterium. Here, we investigated the characteristics of the bacterial population in the late stages of an infection in the B. thuringiensis/Galleria mellonella infection model. Using fluorescent reporters and molecular markers coupled to flow cytometry, we demonstrated that the Spo- cells persist and constitute about half of the population 2 weeks post-infection (p.i.). Protein synthesis and growth recovery assays indicated that they are in a metabolically slowed-down state. These bacteria were extremely resistant to the insect cadaver environment, which did not support growth of in vitro-grown vegetative cells and spores. A transcriptomic analysis of this subpopulation at 7 days p.i. revealed a signature profile of this state, and the expression analysis of individual genes at the cell level showed that more bacteria mount an oxidative stress response as their survival time increases, in agreement with the increase of the free radical level in the host cadaver and in the number of reactive oxygen species (ROS)-producing bacteria. Altogether, these data show for the first time that nonsporulated bacteria are able to survive for a prolonged period of time in the context of an infection and indicate that they engage in a profound adaptation process that leads to their persistence in the host cadaver. IMPORTANCE Bacillus thuringiensis is an entomopathogenic bacterium widely used as a biopesticide. It belongs to the Bacillus cereus group, comprising the foodborne pathogen B. cereus sensu stricto and the anthrax agent Bacillus anthracis. Like other Firmicutes when they encounter harsh conditions, these Gram-positive bacteria can form dormant cells called spores. Due to its highly resistant nature, the spore was considered the unique mode of long-term survival, eclipsing any other form of persistence. Breaking this paradigm, we observed that B. thuringiensis was able to persist in its host cadaver in a nonsporulated form for at least 14 days. Our results show that these bacteria survived in the cadaver environment, which proved hostile for actively growing bacteria by engaging in a profound adaptation process. Studying this facet of the life cycle of a sporulating bacterium provides new fundamental knowledge and might lead to the development of strategies to combat sporulating pathogenic species.
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Affiliation(s)
- Hasna Toukabri
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Didier Lereclus
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Leyla Slamti
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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Guerrero M. GG. Sporulation, Structure Assembly, and Germination in the Soil Bacterium Bacillus thuringiensis: Survival and Success in the Environment and the Insect Host. MICROBIOLOGY RESEARCH 2023. [DOI: 10.3390/microbiolres14020035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
Bacillus thuringiensis (Bt) is a rod-shaped, Gram-positive soil bacterium that belongs to the phylum Firmicutes and the genus Bacillus. It is a spore-forming bacterium. During sporulation, it produces a wide range of crystalline proteins that are toxic to different orders of insects. Sporulation, structure assembly, and germination are essential stages in the cell cycle of B. thuringiensis. The majority of studies on these issues have focused on the model organism Bacillus subtilis, followed by Bacillus cereus and Bacillus anthracis. The machinery for sporulation and germination extrapolated to B. thuringiensis. However, in the light of recent findings concerning the role of the sporulation proteins (SPoVS), the germination receptors (Gr), and the cortical enzymes in Bt, the theory strengthened that conservation in sporulation, structure assembly, and germination programs drive the survival and success of B. thuringiensis in the environment and the insect host. In the present minireview, the latter pinpointed and reviewed.
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Affiliation(s)
- Gloria G. Guerrero M.
- Unidad Académica de Ciencias Biológicas, Laboratorio de Immunobiología, Universidad Autónoma de Zacatecas, Av. Preparatoria S/N, Col. Agronomicas, Zacatecas 98066, Mexico
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7
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Kumar S, Balaya RDA, Kanekar S, Raju R, Prasad TSK, Kandasamy RK. Computational tools for exploring peptide-membrane interactions in gram-positive bacteria. Comput Struct Biotechnol J 2023; 21:1995-2008. [PMID: 36950221 PMCID: PMC10025024 DOI: 10.1016/j.csbj.2023.02.051] [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: 12/21/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023] Open
Abstract
The vital cellular functions in Gram-positive bacteria are controlled by signaling molecules known as quorum sensing peptides (QSPs), considered promising therapeutic interventions for bacterial infections. In the bacterial system QSPs bind to membrane-coupled receptors, which then auto-phosphorylate and activate intracellular response regulators. These response regulators induce target gene expression in bacteria. One of the most reliable trends in drug discovery research for virulence-associated molecular targets is the use of peptide drugs or new functionalities. In this perspective, computational methods act as auxiliary aids for biologists, where methodologies based on machine learning and in silico analysis are developed as suitable tools for target peptide identification. Therefore, the development of quick and reliable computational resources to identify or predict these QSPs along with their receptors and inhibitors is receiving considerable attention. The databases such as Quorumpeps and Quorum Sensing of Human Gut Microbes (QSHGM) provide a detailed overview of the structures and functions of QSPs. The tools and algorithms such as QSPpred, QSPred-FL, iQSP, EnsembleQS and PEPred-Suite have been used for the generic prediction of QSPs and feature representation. The availability of compiled key resources for utilizing peptide features based on amino acid composition, positional preferences, and motifs as well as structural and physicochemical properties, including biofilm inhibitory peptides, can aid in elucidating the QSP and membrane receptor interactions in infectious Gram-positive pathogens. Herein, we present a comprehensive survey of diverse computational approaches that are suitable for detecting QSPs and QS interference molecules. This review highlights the utility of these methods for developing potential biomarkers against infectious Gram-positive pathogens.
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Key Words
- 3-HBA, 3–Hydroxybenzoic Acid
- AAC, Amino Acid Composition
- ABC, ATP-binding cassette
- ACD, Available Chemicals Database
- AIP, Autoinducing Peptide
- AMP, Anti-Microbial Peptide
- ATP, Adenosine Triphosphate
- Agr, Accessory gene regulator
- BFE, Binding Free Energy
- BIP Inhibitors
- BIP, Biofilm Inhibitory Peptides
- BLAST, Basic Local Alignment Search Tool
- BNB, Bernoulli Naïve-Bayes
- CADD, Computer-Aided Drug Design
- CSP, Competence Stimulating Peptide
- CTD, Composition-Transition-Distribution
- D, Aspartate
- DCH, 3,3′-(3,4-dichlorobenzylidene)-bis-(4-hydroxycoumarin)
- DT, Decision Tree
- FDA, Food and Drug Administration
- GBM, Gradient Boosting Machine
- GDC, g-gap Dipeptide
- GNB, Gaussian NB
- Gram-positive bacteria
- H, Histidine
- H-Kinase, Histidine Kinase
- H-phosphotransferase, Histidine Phosphotransferase
- HAM, Hamamelitannin
- HGM, Human Gut Microbiota
- HNP, Human Neutrophil Peptide
- IT, Information Theory Features
- In silico approaches
- KNN, K-Nearest Neighbors
- MCC, Mathew Co-relation Coefficient
- MD, Molecular Dynamics
- MDR, Multiple Drug Resistance
- ML, Machine Learning
- MRSA, Methicillin Resistant S. aureus
- MSL, Multiple Sequence Alignment
- OMR, Omargliptin
- OVP, Overlapping Property Features
- PCP, Physicochemical Properties
- PDB, Protein Data Bank
- PPIs, Protein-Protein Interactions
- PSM, Phenol-Soluble Modulin
- PTM, Post Translational Modification
- QS, Quorum Sensing
- QSCN, QS communication network
- QSHGM, Quorum Sensing of Human Gut Microbes
- QSI, QS Inhibitors
- QSIM, QS Interference Molecules
- QSP inhibitors
- QSP predictors
- QSP, QS Peptides
- QSPR, Quantitative Structure Property Relationship
- Quorum sensing peptides
- RAP, RNAIII-activating protein
- RF, Random Forest
- RIP, RNAIII-inhibiting peptide
- ROC, Receiver Operating Characteristic
- SAR, Structure-Activity Relationship
- SFS, Sequential Forward Search
- SIT, Sitagliptin
- SVM, Support Vector Machine
- TCS, Two-Component Sensory
- TRAP, Target of RAP
- TRG, Trelagliptin
- WHO, World Health Organization
- mRMR, minimum Redundancy and Maximum Relevance
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Affiliation(s)
- Shreya Kumar
- Centre for Integrative Omics Data Science, Yenepoya (Deemed to be University), Mangalore 575018, India
- Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India
| | | | - Saptami Kanekar
- Centre for Integrative Omics Data Science, Yenepoya (Deemed to be University), Mangalore 575018, India
| | - Rajesh Raju
- Centre for Integrative Omics Data Science, Yenepoya (Deemed to be University), Mangalore 575018, India
- Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India
| | | | - Richard K. Kandasamy
- Centre of Molecular Inflammation Research (CEMIR), and Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Department of Laboratory Medicine and Pathology, Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Grizanova EV, Krytsyna TI, Kalmykova GV, Sokolova E, Alikina T, Kabilov M, Coates CJ, Dubovskiy IM. Virulent and necrotrophic strategies of Bacillus thuringiensis in susceptible and resistant insects, Galleria mellonella. Microb Pathog 2023; 175:105958. [PMID: 36572197 DOI: 10.1016/j.micpath.2022.105958] [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: 10/11/2022] [Revised: 12/03/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022]
Abstract
Bacillus thuringiensis (Bt) is one of the most common entomopathogenic bacteria used as a biopesticide, and source of endotoxin genes for generating insect-resistant transgenic plants. The mechanisms underpinning an insect's susceptibility or resistance to B. thuringiensis are diverse. The bacterial lifecycle does not end with the death of a host, they continue to exploit the cadaver to reproduce and sporulate. Herein, we studied the progression of B. thuringiensis subsp. galleriae infection in two populations of wax moth larvae (Galleria mellonella) to gain further insight into the "arms race" between B. thuringiensis virulence and insect defences. Two doses of B. thuringiensis subsp. galleriae (spore and crystalline toxin mixtures) were administered orally to compare the responses of susceptible (S) and resistant (R) populations at ∼30% mortality each. To investigate B. thuringiensis-insect antibiosis, we used a combination of in vivo infection trials, bacterial microbiome analysis, and RNAi targeting the antibacterial peptide gloverin. Within 48 h post-inoculation, B. thuringiensis-resistant insects purged the midgut of bacteria, i.e., colony forming unit numbers fell below detectable levels. Second, B. thuringiensis rapidly modulated gene expression to initiate sporulation (linked to quorum sensing) when exposed to resistant insects in contrast to susceptible G. mellonella. We reinforce earlier findings that elevated levels of antimicrobial peptides, specifically gloverin, are found in the midgut of resistant insects, which is an evolutionary strategy to combat B. thuringiensis infection via its main portal of entry. A sub-population of highly virulent B. thuringiensis can survive the enhanced immune defences of resistant G. mellonella by disrupting the midgut microbiome and switching rapidly to a necrotrophic strategy, prior to sporulation in the cadaver.
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Affiliation(s)
- Ekaterina V Grizanova
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Tatiana I Krytsyna
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Galina V Kalmykova
- Faculty of Physical Engineering, Novosibirsk State Technical University, 630039, Novosibirsk, Russia.
| | - Elina Sokolova
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Tatyana Alikina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630039, Novosibirsk, Russia.
| | - Marsel Kabilov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630039, Novosibirsk, Russia.
| | - Christopher J Coates
- Zoology, Ryan Institute, School of Natural Sciences, University of Galway, Galway, H91 TK33, Ireland; Department of Biosciences, Faculty of Science and Engineering, Swansea University, Swansea, SA2 8PP, Wales, UK.
| | - Ivan M Dubovskiy
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
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Manoharan S, Taylor-Joyce G, Brooker TA, Hernández Rodríguez CS, Hapeshi A, Baldwin V, Baillie L, Oyston PCF, Waterfield NR. From cereus to anthrax and back again: Assessment of the temperature-dependent phenotypic switching in the "cross-over" strain Bacillus cereus G9241. Front Microbiol 2023; 14:1113562. [PMID: 36937299 PMCID: PMC10017872 DOI: 10.3389/fmicb.2023.1113562] [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: 12/01/2022] [Accepted: 02/07/2023] [Indexed: 03/06/2023] Open
Abstract
Bacillus cereus G9241 was isolated from a Louisiana welder suffering from an anthrax-like infection. The organism carries two transcriptional regulators that have previously been proposed to be incompatible with each other in Bacillus anthracis: the pleiotropic transcriptional regulator PlcR found in most members of the Bacillus cereus group but truncated in all B. anthracis isolates, and the anthrax toxin regulator AtxA found in all B. anthracis strains and a few B. cereus sensu stricto strains. Here we report cytotoxic and hemolytic activity of cell free B. cereus G9241 culture supernatants cultured at 25°C to various eukaryotic cells. However, this is not observed at the mammalian infection relevant temperature 37°C, behaving much like the supernatants generated by B. anthracis. Using a combination of genetic and proteomic approaches to understand this unique phenotype, we identified several PlcR-regulated toxins to be secreted highly at 25°C compared to 37°C. Furthermore, results suggest that differential expression of the protease involved in processing the PlcR quorum sensing activator molecule PapR appears to be the limiting step for the production of PlcR-regulated toxins at 37°C, giving rise to the temperature-dependent hemolytic and cytotoxic activity of the culture supernatants. This study provides an insight on how B. cereus G9241 is able to "switch" between B. cereus and B. anthracis-like phenotypes in a temperature-dependent manner, potentially accommodating the activities of both PlcR and AtxA.
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Affiliation(s)
- Shathviga Manoharan
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Grace Taylor-Joyce
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Thomas A. Brooker
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Alexia Hapeshi
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Les Baillie
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | | | - Nicholas R. Waterfield
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
- *Correspondence: Nicholas R. Waterfield,
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10
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Ge Z, Kuang Z, Chen J, Chen J, Liu T, She Z, Lu Y. Comparative genomics analysis of Bacillus velezensis LOH112 isolated from a nonagenarian provides insights into its biocontrol and probiotic traits. Gene 2022; 835:146644. [PMID: 35680027 DOI: 10.1016/j.gene.2022.146644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/28/2022] [Accepted: 06/02/2022] [Indexed: 11/17/2022]
Abstract
Bacillus velezensis has recently received increasing attention as a biological fungicide and a potential probiotic agent because of its broad spectrum of antibacterial and antifungal activities. Here, we evaluated the beneficial traits of a newly isolated B. velezensis strain LOH112 using comprehensive bioinformatics and comparative genomic analyses and in vitro experimental approaches. Whole genome sequencing and assembly results showed that the genome of LOH112 consists of a circular chromosome and a circular plasmid, which encodes proteins involved in important biological processes such as sporulation, quorum sensing, and antibiotic synthesis. LOH112 contains 13 secondary metabolism gene clusters responsible for the production of antimicrobial compounds. In vitro experiments showed that LOH112 effectively inhibits several fungi and Gram-positive pathogenic bacteria, hydrolyzes protein and cellulose, and is capable of forming strong adhesive biofilms. Furthermore, comparative genomics revealed that LOH112 contains 34 strain-specific orthologous gene clusters, including two caseinolytic protease P (clpP) genes responsible for proteomic homeostasis. Selective pressure analysis indicated that the transmembrane transporter and ATP-dependent alanine/valine adenylase genes were strongly positively selected, which may endow LOH112 with better biocontrol ability and potential probiotic properties. Collectively, these results not only provide insights into a deeper understanding of the genomic characterization of LOH112 but also imply the potential application of LOH112 as biocontrol and probiotic agents.
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Affiliation(s)
- Zhenhuang Ge
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhiqi Kuang
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiahao Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China
| | - Junyi Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China
| | - Tianhao Liu
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhigang She
- School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Yongjun Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou 510275, China.
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11
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Korša A, Lo LK, Gandhi S, Bang C, Kurtz J. Oral Immune Priming Treatment Alters Microbiome Composition in the Red Flour Beetle Tribolium castaneum. Front Microbiol 2022; 13:793143. [PMID: 35495655 PMCID: PMC9043903 DOI: 10.3389/fmicb.2022.793143] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
It is now well-established that the microbiome is relevant for many of an organism’s properties and that its composition reacts dynamically to various conditions. The microbiome interacts with host immunity and can play important roles in the defenses against pathogens. In invertebrates, immune priming, that is, improved survival upon secondary exposure to a previously encountered pathogen, can be dependent upon the presence of the gut microbiome. However, it is currently unknown whether the microbiome changes upon priming treatment. We here addressed this question in a well-established model for immune priming, the red flour beetle Tribolium castaneum exposed to the entomopathogenic bacterium Bacillus thuringiensis (Bt). After priming treatments, the microbiota composition of beetle larvae was assessed by deep sequencing of the V1-V2 region of the bacterial 16S rRNA gene. We compared the effect of two established routes of priming treatments in this system: injection priming with heat-killed Bt and oral priming via ingestion of filtered sterilized bacterial spore culture supernatants. For oral priming, we used several strains of Bt known to vary in their ability to induce priming. Our study revealed changes in microbiome composition following the oral priming treatment with two different strains of Bt, only one of which (Bt tenebrionis, Btt) is known to lead to improved survival. In contrast, injection priming treatment with the same bacterial strain did not result in microbiome changes. Combined with the previous results indicating that oral priming with Btt depends on the larval microbiome, this suggests that certain members of the microbiome could be involved in forming an oral priming response in the red flour beetle.
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Affiliation(s)
- Ana Korša
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Lai Ka Lo
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Shrey Gandhi
- Department of Genetic Epidemiology, Institute of Human Genetics, University of Münster, Münster, Germany.,Institute of Immunology, University of Münster, Münster, Germany
| | - Corinna Bang
- Institute of Clinical Molecular Biology, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
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12
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Chen H, Verplaetse E, Jauslin T, Cosson P, Slamti L, Lereclus D. The Fate of Bacteria of the Bacillus cereus Group in the Amoeba Environment. MICROBIAL ECOLOGY 2022; 83:1088-1104. [PMID: 34342700 DOI: 10.1007/s00248-021-01828-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
The Bacillus cereus sensu lato group consists of several closely related species, including B. anthracis, B. cereus sensu stricto, and B. thuringiensis. Spores of these pathogenic bacteria are commonly found in the soil but evidence suggests that they are unable to grow in such a natural environment in the absence of nutrient input. Amoebas have been reported to be an amplifier for several species of pathogenic bacteria and their potential involvement to explain the large amount of B. thuringiensis and B. cereus spores in soil has been frequently proposed. Here, we studied the fate of Bacillus and amoebas when cultured together. We show that the virulence factors produced by B. thuringiensis and B. cereus do not affect the amoeba Acanthamoeba castellanii, which, on the contrary, can phagocytose and effectively digest vegetative Bacillus cells to grow and prevent the formation of cysts. Bacterial spores can germinate in the amoeba environment and the vegetative cells can then form chains or aggregates that appear to be less efficiently phagocyted by the amoeba. The use of transcriptional fusions between fluorescent reporter genes and stationary phase- and sporulation-specific promoters showed that the sporulation process occurs more efficiently in the presence of amoebas than in their absence. Moreover, our results showed the amoeba environment to promote spore germination and allow the bacteria to complete their developmental cycle. Overall, this study suggests that the amoeba-Bacillus interaction creates a virtuous circle in which each protagonist helps the other to develop.
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Affiliation(s)
- Haibo Chen
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Emilie Verplaetse
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Tania Jauslin
- Cell Physiology and Metabolism Dpt, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, CH-1211, Geneva 4, Switzerland
| | - Pierre Cosson
- Cell Physiology and Metabolism Dpt, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, CH-1211, Geneva 4, Switzerland
| | - Leyla Slamti
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Didier Lereclus
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France.
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13
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Zhao L, Liu Q, Xu FH, Liu H, Zhang J, Liu F, Wang G. Identification and analysis of Rap-Phr system in Bacillus cereus 0-9. FEMS Microbiol Lett 2022; 369:6549557. [PMID: 35293995 DOI: 10.1093/femsle/fnac026] [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: 09/25/2021] [Revised: 02/15/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
In this study, eight rap-related genes were found in the Bacillus cereus 0-9 genome; five rap genes were located on chromosomes and three on large plasmids. Five Rap proteins in B. cereus 0-9 were annotated as 'tetratricopeptide repeat proteins'. SMART Server analysis showed that the eight Rap proteins had typical tetrapeptide repeat sequence (TPR) domains. Biofilm assays and crystal violet staining showed that overexpression of the rapp1 and rap5 genes affected the biofilm formation of B. cereus 0-9, and the activities of Rapp1 and Rap5 proteins were inhibited by their corresponding cognate Phr, suggesting that the Rap-Phr quorum sensing (QS) system might also exist in the B. cereus 0-9 strain. In addition, overexpression of rap1 genes inhibited in the extracellular amylase decomposition capacity of B. cereus 0-9. The results of the sporulation assay indicated that overexpression of the eight rap genes inhibited the spore formation of B. cereus 0-9 to varying degrees. These results provide a reference for research on the regulation of the Rap-Phr QS system in B. cereus.
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Affiliation(s)
- Linlin Zhao
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China
| | - Qing Liu
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China
| | - Feng Hua Xu
- School of Pharmaceutical, Henan University, Kaifeng, China
| | - Huiping Liu
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China
| | - Juanmei Zhang
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China.,School of Pharmaceutical, Henan University, Kaifeng, China
| | - Fengying Liu
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China.,Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, China
| | - Gang Wang
- Institute of Microbial Engineering, Laboratory of Bioresource and Applied Microbiology, School of Life Sciences, Henan University, Kaifeng, China.,Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, China
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14
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Waheed H, Mehmood CT, Li Y, Yang Y, Xiao Y. Genetic insights unraveling quorum quenching potential of indigenous isolates from an anaerobic membrane bioreactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 811:152349. [PMID: 34914989 DOI: 10.1016/j.scitotenv.2021.152349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/08/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Despite a few reports of quorum quenching (QQ) in anaerobic membrane bioreactors (AnMBRs), the sensing, regulation and degradation mechanism for quorum sensing (QS) signals by indigenous QQ isolates have been barely studied. This study employed isolation and screening of indigenous QQ strains from anaerobic sludge for acyl-homoserine lactones (AHLs) degradation and membrane biofouling control. High-quality whole genome sequences of Micrococcus luteus anQ-m1, Bacillus pacificus anQ-h4, and Lysinibacillus capsici anQ-h6 were obtained, with a genome size of 2.5, 5.6, and 4.7 Mbp, respectively. Amidase-encoding amiE was the only QQ gene in anQ-m1, while anQ-h6 carries both amiE and lactonase-encoding aiiB genes. Genes responsible for QS autoinducer synthesis were not identified in anQ-m1 and anQ-h6, suggesting low potential of biofilm promotion via QS. Despite a peptidic QS system responsible for biofilm formation, anQ-h4 bears the most comprehensive QQ system, including amiE-amidase, aiiA-lactonase, CYP102A5-cytochrome oxidoreductase, and lsrK-autoinducer-2 kinase. This study elucidates QS and QQ mechanisms of potential anaerobes and provides fundamentals for designing QQ consortia to effectively control biofouling in AnMBRs.
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Affiliation(s)
- Hira Waheed
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong 515063, China
| | - Ch Tahir Mehmood
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong 515063, China; Department of Chemical Engineering, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong 515063, China
| | - Yiwei Li
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong 515063, China
| | - Yongyu Yang
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong 515063, China
| | - Yeyuan Xiao
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong 515063, China.
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15
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Lin Y, Briandet R, Kovács ÁT. Bacillus cereus sensu lato biofilm formation and its ecological importance. Biofilm 2022; 4:100070. [PMID: 35243332 PMCID: PMC8861577 DOI: 10.1016/j.bioflm.2022.100070] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 12/20/2022] Open
Abstract
Biofilm formation is a ubiquitous process of bacterial communities that enables them to survive and persist in various environmental niches. The Bacillus cereus group includes phenotypically diversified species that are widely distributed in the environment. Often, B. cereus is considered a soil inhabitant, but it is also commonly isolated from plant roots, nematodes, and food products. Biofilms differ in their architecture and developmental processes, reflecting adaptations to specific niches. Importantly, some B. cereus strains are foodborne pathogens responsible for two types of gastrointestinal diseases, diarrhea and emesis, caused by distinct toxins. Thus, the persistency of biofilms is of particular concern for the food industry, and understanding the underlying mechanisms of biofilm formation contributes to cleaning procedures. This review focuses on the genetic background underpinning the regulation of biofilm development, as well as the matrix components associated with biofilms. We also reflect on the correlation between biofilm formation and the development of highly resistant spores. Finally, advances in our understanding of the ecological importance and evolution of biofilm formation in the B. cereus group are discussed.
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16
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Ruiz CH, Osorio-Llanes E, Trespalacios MH, Mendoza-Torres E, Rosales W, Gómez CMM. Quorum Sensing Regulation as a Target for Antimicrobial Therapy. Mini Rev Med Chem 2021; 22:848-864. [PMID: 34856897 DOI: 10.2174/1389557521666211202115259] [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: 10/04/2020] [Revised: 05/20/2021] [Accepted: 09/04/2021] [Indexed: 11/22/2022]
Abstract
Some bacterial species use a cell-to-cell communication mechanism called Quorum Sensing (QS). Bacteria release small diffusible molecules, usually termed signals which allow the activation of beneficial phenotypes that guarantee bacterial survival and the expression of a diversity of virulence genes in response to an increase in population density. The study of the molecular mechanisms that relate signal molecules with bacterial pathogenesis is an area of growing interest due to its use as a possible therapeutic alternative through the development of synthetic analogues of autoinducers as a strategy to regulate bacterial communication as well as the study of bacterial resistance phenomena, the study of these relationships is based on the structural diversity of natural or synthetic autoinducers and their ability to inhibit bacterial QS, which can be approached with a molecular perspective from the following topics: i) Molecular signals and their role in QS regulation; ii) Strategies in the modulation of Quorum Sensing; iii) Analysis of Bacterial QS circuit regulation strategies; iv) Structural evolution of natural and synthetic autoinducers as QS regulators. This mini-review allows a molecular view of the QS systems, showing a perspective on the importance of the molecular diversity of autoinducer analogs as a strategy for the design of new antimicrobial agents.
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Affiliation(s)
- Caterine Henríquez Ruiz
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Estefanie Osorio-Llanes
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Mayra Hernández Trespalacios
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Evelyn Mendoza-Torres
- Faculty of Health Sciences. Grupo de Investigación Avanzada en Biomedicina-Universidad Libre. Barranquilla. Colombia
| | - Wendy Rosales
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Carlos Mario Meléndez Gómez
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
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17
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Peña-Rico MA, Bravo-D HR, Roldan-Sabino C, Castro-Cerritos KV, Huerta-Heredia A, Navarro-Mtz AK. Addition of proteinase K during the culture alter the physiology of Bacillus thuringiensis culture and the cry1Ac, nprX, nprA, and spo0A gene transcription. Antonie van Leeuwenhoek 2021; 115:89-102. [PMID: 34797466 DOI: 10.1007/s10482-021-01683-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022]
Abstract
Bacillus thuringiensis is the major bioinsecticide worldwide produced due to the Cry protein activity. Several studies have been done to improve the cost-productivity relation. The neutral protease A (NprA) is the major extracellular protein massively produced during the stationary phase by this bacterium, contributing to the Cry proteins' degradation. Also, the deletion of aprA and nprA genes enhanced the yield of Cry protein, stabilizing it. Therefore, to increase Cry production, one possibility is to degrade the NprA protease in the culture media. In the present study, proteinase K was used to hydrolyze the NprA to increase Cry production. Proteinase K was added during the exponential growth of B. thuringiensis culture. The bacilli and endospores were measured along all culture, while the Cry protein was measured at the end of the culture. The addition of PK affects the bacilli and spore kinetics positively but negatively to the Cry protein (there is no Cry protein detection). Therefore, the gene expression of the cry1Ac, nprX, nprA, and spo0A was measured. The expression of each gene was followed along all culture. Results demonstrated that PK alters both the transcriptional levels and the expression order of the genes.
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Affiliation(s)
- Miguel A Peña-Rico
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Humberto R Bravo-D
- División de Estudios de Posgrado, Doctorado en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Crisanto Roldan-Sabino
- Ingeniería en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Karla V Castro-Cerritos
- Instituto de Química Aplicada, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Ariana Huerta-Heredia
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.,CONACyT-UNPA, Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - A Karin Navarro-Mtz
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.
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18
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Lin Y, Alstrup M, Pang JKY, Maróti G, Er-Rafik M, Tourasse N, Økstad OA, Kovács ÁT. Adaptation of Bacillus thuringiensis to Plant Colonization Affects Differentiation and Toxicity. mSystems 2021; 6:e0086421. [PMID: 34636664 PMCID: PMC8510532 DOI: 10.1128/msystems.00864-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/27/2021] [Indexed: 01/11/2023] Open
Abstract
The Bacillus cereus group (Bacillus cereus sensu lato) has a diverse ecology, including various species that are vertebrate or invertebrate pathogens. Few isolates from the B. cereus group have however been demonstrated to benefit plant growth. Therefore, it is crucial to explore how bacterial development and pathogenesis evolve during plant colonization. Herein, we investigated Bacillus thuringiensis (Cry-) adaptation to the colonization of Arabidopsis thaliana roots and monitored changes in cellular differentiation in experimentally evolved isolates. Isolates from two populations displayed improved iterative ecesis on roots and increased virulence against insect larvae. Molecular dissection and recreation of a causative mutation revealed the importance of a nonsense mutation in the rho transcription terminator gene. Transcriptome analysis revealed how Rho impacts various B. thuringiensis genes involved in carbohydrate metabolism and virulence. Our work suggests that evolved multicellular aggregates have a fitness advantage over single cells when colonizing plants, creating a trade-off between swimming and multicellularity in evolved lineages, in addition to unrelated alterations in pathogenicity. IMPORTANCE Biologicals-based plant protection relies on the use of safe microbial strains. During application of biologicals to the rhizosphere, microbes adapt to the niche, including genetic mutations shaping the physiology of the cells. Here, the experimental evolution of Bacillus thuringiensis lacking the insecticide crystal toxins was examined on the plant root to reveal how adaptation shapes the differentiation of this bacterium. Interestingly, evolution of certain lineages led to increased hemolysis and insect larva pathogenesis in B. thuringiensis driven by transcriptional rewiring. Further, our detailed study reveals how inactivation of the transcription termination protein Rho promotes aggregation on the plant root in addition to altered differentiation and pathogenesis in B. thuringiensis.
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Affiliation(s)
- Yicen Lin
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Monica Alstrup
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Janet Ka Yan Pang
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Mériem Er-Rafik
- National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Lyngby, Denmark
| | - Nicolas Tourasse
- Université Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, Bordeaux, France
| | - Ole Andreas Økstad
- Centre for Integrative Microbial Evolution, University of Oslo, Oslo, Norway
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Ákos T. Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
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19
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Salamun, Fatimah, Fauzi A, Praduwana SN, Ni'matuzahroh. Larvicidal toxicity and parasporal inclusion of native Bacillus thuringiensis BK5.2 against Aedes aegypti. J Basic Clin Physiol Pharmacol 2021; 32:379-384. [PMID: 34214353 DOI: 10.1515/jbcpp-2020-0472] [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: 11/29/2020] [Accepted: 02/21/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Native Bacillus thuringiensis BK5.2, isolated from soil of Baluran National Park, East Java, Indonesia, has been shown to be toxic against Aedes aegypti larvae. This study aims to determine the strength and the speed of the toxicity of B. thuringiensis BK5.2 against A. aegypti larvae in lethal concentration (LC) and lethal time (LT), as well as detection of toxin structure and parasporal inclusion. METHODS LC values were determined by the mortality of A. aegypti third instar larvae after 24 and 48 h exposure to five various concentrations of B. thuringiensis BK5.2, while LT values were determined based on the mortality of A. aegypti third instar larvae due to exposure to LC90 concentration at 0; 0.5; 1; 2; 4; 8; 10; 20; 24; and 48 h. Larvicidal toxicity was determined based on value of LC50 and LC90 (CFU/mL), as well as LT50 and LT90 (hours) analysed with Probit analysis. Parasporal inclusion was detected using transmission electron microscope (TEM) and scanning electron microscope (SEM). RESULTS Based on bioassay, LC50 and LC90 values were 11.6 × 106 and 22.7 × 106 CFU/mL, respectively, at 24 h exposure, as well as 8.3 × 106 and 15.4 × 106 CFU/mL, respectively, at 48 h exposure, while the value of LT50 and LT90 were 19.0 and 26.6 h, respectively. Morphological observation of the dead larvae showed there was damage on abdomen and thorax region. Detection by TEM and SEM showed there was cuboidal parasporal inclusion. CONCLUSIONS Native B. thuringiensis BK5.2 has high toxicity against A. aegypti larvae and detected flatcuboidal toxin in parasporal inclusion.
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Affiliation(s)
- Salamun
- Faculty of Science and Technology, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
| | - Fatimah
- Faculty of Science and Technology, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
| | - Ahmad Fauzi
- Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Seling N Praduwana
- Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Ni'matuzahroh
- Faculty of Science and Technology, Faculty of Advanced Technology and Multidiscipline, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
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20
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Shikov AE, Malovichko YV, Lobov AA, Belousova ME, Nizhnikov AA, Antonets KS. The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis. Int J Mol Sci 2021; 22:2244. [PMID: 33668147 PMCID: PMC7956386 DOI: 10.3390/ijms22052244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/02/2021] [Accepted: 02/18/2021] [Indexed: 02/06/2023] Open
Abstract
Bacillus thuringiensis, commonly referred to as Bt, is an object of the lasting interest of microbiologists due to its highly effective insecticidal properties, which make Bt a prominent source of biologicals. To categorize the exuberance of Bt strains discovered, serotyping assays are utilized in which flagellin serves as a primary seroreactive molecule. Despite its convenience, this approach is not indicative of Bt strains' phenotypes, neither it reflects actual phylogenetic relationships within the species. In this respect, comparative genomic and proteomic techniques appear more informative, but their use in Bt strain classification remains limited. In the present work, we used a bottom-up proteomic approach based on fluorescent two-dimensional difference gel electrophoresis (2D-DIGE) coupled with liquid chromatography/tandem mass spectrometry(LC-MS/MS) protein identification to assess which stage of Bt culture, vegetative or spore, would be more informative for strain characterization. To this end, the proteomic differences for the israelensis-attributed strains were assessed to compare sporulating cultures of the virulent derivative to the avirulent one as well as to the vegetative stage virulent bacteria. Using the same approach, virulent spores of the israelensis strain were also compared to the spores of strains belonging to two other major Bt serovars, namely darmstadiensis and thuringiensis. The identified proteins were analyzed regarding the presence of the respective genes in the 104 Bt genome assemblies available at open access with serovar attributions specified. Of 21 proteins identified, 15 were found to be encoded in all the present assemblies at 67% identity threshold, including several virulence factors. Notable, individual phylogenies of these core genes conferred neither the serotyping nor the flagellin-based phylogeny but corroborated the reconstruction based on phylogenomics approaches in terms of tree topology similarity. In its turn, the distribution of accessory protein genes was not confined to the existing serovars. The obtained results indicate that neither gene presence nor the core gene sequence may serve as distinctive bases for the serovar attribution, undermining the notion that the serotyping system reflects strains' phenotypic or genetic similarity. We also provide a set of loci, which fit in with the phylogenomics data plausibly and thus may serve for draft phylogeny estimation of the novel strains.
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Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (M.E.B.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia;
| | - Yury V. Malovichko
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (M.E.B.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia;
| | - Arseniy A. Lobov
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia;
- Laboratory of Regenerative Biomedicine, Institute of Cytology of the Russian Academy of Science, 194064 St. Petersburg, Russia
| | - Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (M.E.B.); (A.A.N.)
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (M.E.B.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia;
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (M.E.B.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia;
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The Alternative Sigma Factor SigB Is Required for the Pathogenicity of Bacillus thuringiensis. J Bacteriol 2020; 202:JB.00265-20. [PMID: 32817096 DOI: 10.1128/jb.00265-20] [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: 05/04/2020] [Accepted: 08/11/2020] [Indexed: 11/20/2022] Open
Abstract
To adapt to changing and potentially hostile environments, bacteria can activate the transcription of genes under the control of alternative sigma factors, such as SigB, a master regulator of the general stress response in several Gram-positive species. Bacillus thuringiensis is a Gram-positive spore-forming invertebrate pathogen whose life cycle includes a variety of environments, including plants and the insect hemocoel or gut. Here, we assessed the role of SigB during the infectious cycle of B. thuringiensis in a Galleria mellonella insect model. We used a fluorescent reporter coupled to flow cytometry and showed that SigB was activated in vivo We also showed that the pathogenicity of the ΔsigB mutant was severely affected when inoculated via the oral route, suggesting that SigB is critical for B. thuringiensis adaptation to the gut environment of the insect. We could not detect an effect of the sigB deletion on the survival of the bacteria or on their sporulation efficiency in the cadavers. However, the gene encoding the pleiotropic regulator Spo0A was upregulated in the ΔsigB mutant cells during the infectious process.IMPORTANCE Pathogenic bacteria often need to transition between different ecosystems, and their ability to cope with such variations is critical for their survival. Several Gram-positive species have developed an adaptive response mediated by the general stress response alternative sigma factor SigB. In order to understand the ecophysiological role of this regulator in Bacillus thuringiensis, an entomopathogenic bacterium widely used as a biopesticide, we sought to examine the fate of a ΔsigB mutant during its life cycle in the natural setting of an insect larva. This allowed us, in particular, to show that SigB was activated during infection and that it was required for the pathogenicity of B. thuringiensis via the oral route of infection.
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Lingeswaran A, Metton C, Henry C, Monnet V, Juillard V, Gardan R. Export of Rgg Quorum Sensing Peptides is Mediated by the PptAB ABC Transporter in Streptococcus Thermophilus Strain LMD-9. Genes (Basel) 2020; 11:genes11091096. [PMID: 32961685 PMCID: PMC7564271 DOI: 10.3390/genes11091096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 12/26/2022] Open
Abstract
In streptococci, intracellular quorum sensing pathways are based on quorum-sensing systems that are responsible for peptide secretion, maturation, and reimport. These peptides then interact with Rgg or ComR transcriptional regulators in the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP) family, whose members are found in Gram-positive bacteria. Short hydrophobic peptides (SHP) interact with Rgg whereas ComS peptides interact with ComR regulators. To date, in Streptococcus thermophilus, peptide secretion, maturation, and extracellular fate have received little attention, even though this species has several (at least five) genes encoding Rgg regulators and one encoding a ComR regulator. We studied pheromone export in this species, focusing our attention on PptAB, which is an exporter of signaling peptides previously identified in Enterococcus faecalis, pathogenic streptococci and Staphylococcus aureus. In the S. thermophilus strain LMD-9, we showed that PptAB controlled three regulation systems, two SHP/Rgg systems (SHP/Rgg1358 and SHP/Rgg1299), and the ComS/ComR system, while using transcriptional fusions and that PptAB helped to produce and export at least three different mature SHPs (SHP1358, SHP1299, and SHP279) peptides while using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using a deep sequencing approach (RNAseq), we showed that the exporter PptAB, the membrane protease Eep, and the oligopeptide importer Ami controlled the transcription of the genes that were located downstream from the five non-truncated rgg genes as well as few distal genes. This led us to propose that the five non-truncated shp/rgg loci were functional. Only three shp genes were expressed in our experimental condition. Thus, this transcriptome analysis also highlighted the complex interconnected network that exists between SHP/Rgg systems, where a few homologous signaling peptides likely interact with different regulators.
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Rap-Phr Systems from Plasmids pAW63 and pHT8-1 Act Together To Regulate Sporulation in the Bacillus thuringiensis Serovar kurstaki HD73 Strain. Appl Environ Microbiol 2020; 86:AEM.01238-20. [PMID: 32680861 DOI: 10.1128/aem.01238-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Bacillus thuringiensis is a Gram-positive spore-forming bacterium pathogenic to various insect species. This property is due to the Cry toxins encoded by plasmid genes and mostly produced during sporulation. B. thuringiensis contains a remarkable number of extrachromosomal DNA molecules and a great number of plasmid rap-phr genes. Rap-Phr quorum-sensing systems regulate different bacterial processes, notably the commitment to sporulation in Bacillus species. Rap proteins are quorum sensors acting as phosphatases on Spo0F, an intermediate of the sporulation phosphorelay, and are inhibited by Phr peptides that function as signaling molecules. In this study, we characterize the Rap63-Phr63 system encoded by the pAW63 plasmid from the B. thuringiensis serovar kurstaki HD73 strain. Rap63 has moderate activity on sporulation and is inhibited by the Phr63 peptide. The rap63-phr63 genes are cotranscribed, and the phr63 gene is also transcribed from a σH-specific promoter. We show that Rap63-Phr63 regulates sporulation together with the Rap8-Phr8 system harbored by plasmid pHT8_1 of the HD73 strain. Interestingly, the deletion of both phr63 and phr8 genes in the same strain has a greater negative effect on sporulation than the sum of the loss of each phr gene. Despite the similarities in the Phr8 and Phr63 sequences, there is no cross talk between the two systems. Our results suggest a synergism of these two Rap-Phr systems in the regulation of the sporulation of B. thuringiensis at the end of the infectious cycle in insects, thus pointing out the roles of the plasmids in the fitness of the bacterium.IMPORTANCE The life cycle of Bacillus thuringiensis in insect larvae is regulated by quorum-sensing systems of the RNPP family. After the toxemia caused by Cry insecticidal toxins, the sequential activation of these systems allows the bacterium to trigger first a state of virulence (regulated by PlcR-PapR) and then a necrotrophic lifestyle (regulated by NprR-NprX); ultimately, sporulation is controlled by the Rap-Phr systems. Our study describes a new rap-phr operon carried by a B. thuringiensis plasmid and shows that the Rap protein has a moderate effect on sporulation. However, this system, in combination with another plasmidic rap-phr operon, provides effective control of sporulation when the bacteria develop in the cadavers of infected insect larvae. Overall, this study highlights the important adaptive role of the plasmid Rap-Phr systems in the developmental fate of B. thuringiensis and its survival within its ecological niche.
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Unique inducible filamentous motility identified in pathogenic Bacillus cereus group species. ISME JOURNAL 2020; 14:2997-3010. [PMID: 32770116 PMCID: PMC7784679 DOI: 10.1038/s41396-020-0728-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 07/11/2020] [Accepted: 07/23/2020] [Indexed: 01/03/2023]
Abstract
Active migration across semi-solid surfaces is important for bacterial success by facilitating colonization of unoccupied niches and is often associated with altered virulence and antibiotic resistance profiles. We isolated an atmospheric contaminant, subsequently identified as a new strain of Bacillus mobilis, which showed a unique, robust, rapid, and inducible filamentous surface motility. This flagella-independent migration was characterized by formation of elongated cells at the expanding edge and was induced when cells were inoculated onto lawns of metabolically inactive Campylobacter jejuni cells, autoclaved bacterial biomass, adsorbed milk, and adsorbed blood atop hard agar plates. Phosphatidylcholine (PC), bacterial membrane components, and sterile human fecal extracts were also sufficient to induce filamentous expansion. Screening of eight other Bacillus spp. showed that filamentous motility was conserved amongst B. cereus group species to varying degrees. RNA-Seq of elongated expanding cells collected from adsorbed milk and PC lawns versus control rod-shaped cells revealed dysregulation of genes involved in metabolism and membrane transport, sporulation, quorum sensing, antibiotic synthesis, and virulence (e.g., hblA/B/C/D and plcR). These findings characterize the robustness and ecological significance of filamentous surface motility in B. cereus group species and lay the foundation for understanding the biological role it may play during environment and host colonization.
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Optimal Response to Quorum-Sensing Signals Varies in Different Host Environments with Different Pathogen Group Size. mBio 2020; 11:mBio.00535-20. [PMID: 32487754 PMCID: PMC7267880 DOI: 10.1128/mbio.00535-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Quorum sensing describes the ability of microbes to alter gene regulation according to their local population size. Some successful theory suggests that this is a form of cooperation, namely, investment in shared products is only worthwhile if there are sufficient bacteria making the same product. This theory can explain the genetic diversity in these signaling systems in Gram-positive bacteria, such as Bacillus and Staphylococcus sp. The possible advantages gained by rare genotypes (which can exploit the products of their more common neighbors) could explain why different genotypes can coexist. We show that while these social interactions can occur in simple laboratory experiments, they do not occur in naturalistic infections using an invertebrate pathogen, Bacillus thuringiensis. Instead, our results suggest that different genotypes are adapted to differently sized hosts. Overall, social models are not easily applied to this system, implying that a different explanation for this form of quorum sensing is required. The persistence of genetic variation in master regulators of gene expression, such as quorum-sensing systems, is hard to explain. Here, we investigated two alternative hypotheses for the prevalence of polymorphic quorum sensing in Gram-positive bacteria, i.e., the use of different signal/receptor pairs (‘pherotypes’) to regulate the same functions. First, social interactions between pherotypes or ‘facultative cheating’ may favor rare variants that exploit the signals of others. Second, different pherotypes may increase fitness in different environments. We evaluated these hypotheses in the invertebrate pathogen Bacillus thuringiensis, using three pherotypes expressed in a common genetic background. Facultative cheating could occur in well-mixed host homogenates provided there was minimal cross talk between competing pherotypes. However, facultative cheating did not occur when spatial structure was increased in static cultures or in naturalistic oral infections, where common pherotypes had higher fitness. There was clear support for environment-dependent fitness; pherotypes varied in responsiveness to signals and in mean competitive fitness. Notably, competitive fitness varied with group size. In contrast to typical social evolution models of quorum sensing which predict higher response to signal at larger group size, the pherotype with highest responsiveness to signals performed best in smaller hosts where infections have a lower pathogen group size. In this system, low signal abundance appears to limit fitness in hosts, while the optimal level of response to signals varies in different host environments.
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Multiple and Overlapping Functions of Quorum Sensing Proteins for Cell Specialization in Bacillus Species. J Bacteriol 2020; 202:JB.00721-19. [PMID: 32071096 DOI: 10.1128/jb.00721-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In bacterial populations, quorum sensing (QS) systems participate in the regulation of specialization processes and regulate collective behaviors that mediate interactions and allow survival of the species. In Gram-positive bacteria, QS systems of the RRNPP family (Rgg, Rap, NprR, PlcR, and PrgX) consist of intracellular receptors and their cognate signaling peptides. Two of these receptors, Rap and NprR, have regained attention in Bacillus subtilis and the Bacillus cereus group. Some Rap proteins, such as RapH and Rap60, are multifunctional and/or redundant in function, linking the specialization processes of sporulation and competence, as well as global expression changes in the transition phase in B. subtilis NprR, an evolutionary intermediate between Rap and RRNPP transcriptional activators, is a bifunctional regulator that modulates sporulation initiation and activates nutrient scavenging genes. In this review, we discuss how these receptors switch between functions and connect distinct signaling pathways. Based on structural evidence, we propose that RapH and Rap60 should be considered moonlighting proteins. Additionally, we analyze an evolutionary and ecological perspective to understand the multifunctionality and functional redundancy of these regulators in both Bacillus spp. and non-Bacillus Firmicutes Understanding the mechanistic, structural, ecological, and evolutionary basis for the multifunctionality and redundancy of these QS systems is a key step for achieving the development of innovative technologies for health and agriculture.
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Wu S, Liu J, Liu C, Yang A, Qiao J. Quorum sensing for population-level control of bacteria and potential therapeutic applications. Cell Mol Life Sci 2020; 77:1319-1343. [PMID: 31612240 PMCID: PMC11104945 DOI: 10.1007/s00018-019-03326-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/13/2019] [Accepted: 09/30/2019] [Indexed: 02/07/2023]
Abstract
Quorum sensing (QS), a microbial cell-to-cell communication process, dynamically regulates a variety of metabolism and physiological activities. In this review, we provide an update on QS applications based on autoinducer molecules including acyl-homoserine lactones (AHLs), auto-inducing peptides (AIPs), autoinducer 2 (AI-2) and indole in population-level control of bacteria, and highlight the potential in developing novel clinical therapies. We summarize the development in the combination of various genetic circuits such as genetic oscillators, toggle switches and logic gates with AHL-based QS devices in Gram-negative bacteria. An overview is then offered to the state-of-the-art of much less researched applications of AIP-based QS devices with Gram-positive bacteria, followed by a review of the applications of AI-2 and indole based QS for interspecies communication among microbial communities. Building on these general-purpose QS applications, we highlight the disruptions and manipulations of QS devices as potential clinical therapies for diseases caused by biofilm formation, antibiotic resistance and the phage invasion. The last part of reviewed literature is dedicated to mathematical modelling for QS applications. Finally, the key challenges and future perspectives of QS applications in monoclonal synthetic biology and synthetic ecology are discussed.
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Affiliation(s)
- Shengbo Wu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Jiaheng Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China
| | - Chunjiang Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Aidong Yang
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK.
| | - Jianjun Qiao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China.
- Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China.
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Rap Protein Paralogs of Bacillus thuringiensis: a Multifunctional and Redundant Regulatory Repertoire for the Control of Collective Functions. J Bacteriol 2020; 202:JB.00747-19. [PMID: 31871034 DOI: 10.1128/jb.00747-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 12/20/2019] [Indexed: 01/01/2023] Open
Abstract
Quorum sensing (QS) is a mechanism of synthesis and detection of signaling molecules to regulate gene expression and coordinate behaviors in bacterial populations. In Bacillus subtilis, multiple paralog Rap-Phr QS systems (receptor-signaling peptides) are highly redundant and multifunctional, interconnecting the regulation of differentiation processes such as sporulation and competence. However, their functions in the Bacillus cereus group are largely unknown. We evaluated the functions of Rap proteins in Bacillus thuringiensis Bt8741, which codes for eight Rap-Phr systems; these were individually overexpressed to study their participation in sporulation, biofilm formation, spreading, and extracellular proteolytic activity. Our results show that four Rap-Phr systems (RapC, RapK, RapF, and RapLike) inhibit sporulation, two of which (RapK and RapF) probably dephosphorylate Spo0F from the Spo0A phosphorelay; these two Rap proteins also inhibit biofilm formation. Four systems (RapC, RacF1, RacF2, and RapLike) participate in spreading inhibition; finally, six systems (RapC, -F, -F2, -I, and -I1 and RapLike) decrease extracellular proteolytic activity. We foresee that functions performed by Rap proteins of Bt8741 could also be carried out by Rap homologs in other strains within the B. cereus group. These results indicate that Rap-Phr systems constitute a highly multifunctional and redundant regulatory repertoire that enables B. thuringiensis and other species from the B. cereus group to efficiently regulate collective functions during their life cycle in the face of changing environments.IMPORTANCE The Bacillus cereus group of bacteria includes species of high economic, clinical, biological warfare, and biotechnological interest, e.g., B. anthracis in bioterrorism, B. cereus in food intoxications, and B. thuringiensis in biocontrol. Knowledge about the ecology of these bacteria is hindered by our limited understanding of the regulatory circuits that control differentiation and specialization processes. Here, we uncover the participation of eight Rap quorum-sensing receptors in collective functions of B. thuringiensis These proteins are highly multifunctional and redundant in their functions, linking ecologically relevant processes such as sporulation, biofilm formation, spreading, extracellular proteolytic activity, and probably other functions in species from the B. cereus group.
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Wang CH, Hsieh YH, Powers ZM, Kao CY. Defeating Antibiotic-Resistant Bacteria: Exploring Alternative Therapies for a Post-Antibiotic Era. Int J Mol Sci 2020; 21:E1061. [PMID: 32033477 PMCID: PMC7037027 DOI: 10.3390/ijms21031061] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 12/11/2022] Open
Abstract
Antibiotics are one of the greatest medical advances of the 20th century, however, they are quickly becoming useless due to antibiotic resistance that has been augmented by poor antibiotic stewardship and a void in novel antibiotic discovery. Few novel classes of antibiotics have been discovered since 1960, and the pipeline of antibiotics under development is limited. We therefore are heading for a post-antibiotic era in which common infections become untreatable and once again deadly. There is thus an emergent need for both novel classes of antibiotics and novel approaches to treatment, including the repurposing of existing drugs or preclinical compounds and expanded implementation of combination therapies. In this review, we highlight to utilize alternative drug targets/therapies such as combinational therapy, anti-regulator, anti-signal transduction, anti-virulence, anti-toxin, engineered bacteriophages, and microbiome, to defeat antibiotic-resistant bacteria.
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Affiliation(s)
- Chih-Hung Wang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan;
| | - Yi-Hsien Hsieh
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung 40201, Taiwan;
| | - Zachary M. Powers
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA;
| | - Cheng-Yen Kao
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei 11221, Taiwan
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Huillet E, Bridoux L, Barboza I, Lemy C, André-Leroux G, Lereclus D. The signaling peptide PapR is required for the activity of the quorum-sensor PlcRa in Bacillus thuringiensis. MICROBIOLOGY-SGM 2020; 166:398-410. [PMID: 32067627 DOI: 10.1099/mic.0.000883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The transcriptional regulator PlcR, its cognate cell-cell signaling heptapeptide PapR7, and the oligopeptide permease OppABCDF, required for PapR7 import, form a quorum-sensing system that controls the expression of virulence factors in Bacillus cereus and Bacillus thuringiensis species. In B. cereus strain ATCC 14579, the transcriptional regulator PlcRa activates the expression of abrB2 gene, which encodes an AbrB-like transcriptional regulator involved in cysteine biosynthesis. PlcRa is a structural homolog of PlcR: in particular, its C-terminal TPR peptide-binding domain could be similarly arranged as in PlcR. The signaling peptide of PlcRa is not known. As PlcRa is a PlcR-like protein, the cognate PapR7 peptide (ADLPFEF) is a relevant candidate to act as a signaling peptide for PlcRa activation. Also, the putative PapRa7 peptide (CSIPYEY), encoded by the papRa gene adjacent to the plcRa gene, is a relevant candidate as addition of synthetic PapRa7 induces a dose-dependent increase of abrB2 expression. To address the issue of peptide selectivity of PlcRa, the role of PapR and PapRa peptides in PlcRa activity was investigated in B. thuringiensis 407 strain, by genetic and functional complementation analyses. A transcriptional fusion between the promoter of abrB2 and lacZ was used to monitor the PlcRa activity in various genetic backgrounds. We demonstrated that PapR was necessary and sufficient for PlcRa activity. We showed that synthetic PapRs from pherogroups II, III and IV and synthetic PapRa7 were able to trigger abrB2 expression, suggesting that PlcRa is less selective than PlcR. Lastly, the mode of binding of PlcRa was addressed using an in silico approach. Overall, we report a new role for PapR as a signaling peptide for PlcRa activity and show a functional link between PlcR and PlcRa regulons in B. thuringiensis.
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Affiliation(s)
- Eugénie Huillet
- INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France
| | - Ludovic Bridoux
- INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France
| | - Isabelle Barboza
- Present address: IBENS Institute, CNRS UMR8197, Inserm U1024, Paris, France.,INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France
| | - Christelle Lemy
- Present address: CERTIA, Unité Matériaux et Transformations, INRA, Villeneuve d'Ascq, France.,INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France
| | | | - Didier Lereclus
- INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France
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The oligopeptide ABC-importers are essential communication channels in Gram-positive bacteria. Res Microbiol 2019; 170:338-344. [PMID: 31376485 DOI: 10.1016/j.resmic.2019.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/12/2019] [Indexed: 12/27/2022]
Abstract
The transport of peptides in microorganisms plays an important role in their physiology and behavior, both as a nutrient source and as a proxy to sense their environment. This latter function is evidenced in Gram-positive bacteria where cell-cell communication is mediated by small peptides. Here, we highlight the importance of the oligopeptide permease (Opp) systems in the various major processes controlled by signaling peptides, such as sporulation, virulence and conjugation. We underline that the functioning of these communication systems is tightly linked to the developmental status of the bacteria via the regulation of opp gene expression by transition phase regulators.
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Yehuda A, Slamti L, Malach E, Lereclus D, Hayouka Z. Elucidating the Hot Spot Residues of Quorum Sensing Peptidic Autoinducer PapR by Multiple Amino Acid Replacements. Front Microbiol 2019; 10:1246. [PMID: 31231335 PMCID: PMC6568020 DOI: 10.3389/fmicb.2019.01246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022] Open
Abstract
The quorum sensing (QS) system of Bacillus cereus, an opportunistic human pathogen, utilizes the autoinducing PapR peptide signal that mediates the activation of the pleiotropic virulence regulator PlcR. A set of synthetic 7-mer PapR-derived peptides (PapR7; ADLPFEF) have been shown to inhibit efficiently the PlcR regulon activity and the production of virulence factors, reflected by a loss in hemolytic activity without affecting bacterial growth. Interestingly, these first potent synthetic inhibitors involved D-amino acid or alanine replacements of three amino acids; proline, glutamic acid, and phenylalanine of the heptapeptide PapR. To better understand the role of these three positions in PlcR activity, we report herein the second generation design, synthesis, and characterization of PapR7-derived combinations, alternate double and triple alanine and D-amino acids replacement at these positions. Our findings generate a new set of non-native PapR7-derived peptides that inhibit the PlcR regulon activity and the production of virulence factors. Using the amino acids substitution strategy, we revealed the role of proline and glutamic acid on PlcR regulon activation. Moreover, we demonstrated that the D-Glutamic acid substitution was crucial for the design of stronger PlcR antagonists. These peptides represent potent synthetic inhibitors of B. cereus QS and constitute new and readily accessible chemical tools for the study of the PlcR system. Our method might be applied to other quorum sensing systems to design new anti-virulence agents.
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Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Leyla Slamti
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Einav Malach
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
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Lima-Pérez J, López-Pérez M, Viniegra-González G, Loera O. Solid-state fermentation of Bacillus thuringiensis var kurstaki HD-73 maintains higher biomass and spore yields as compared to submerged fermentation using the same media. Bioprocess Biosyst Eng 2019; 42:1527-1535. [DOI: 10.1007/s00449-019-02150-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/08/2019] [Indexed: 01/02/2023]
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Cardoso PDF, Perchat S, Vilas-Boas LA, Lereclus D, Vilas-Bôas GT. Diversity of the Rap-Phr quorum-sensing systems in the Bacillus cereus group. Curr Genet 2019; 65:1367-1381. [PMID: 31104082 DOI: 10.1007/s00294-019-00993-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 12/20/2022]
Abstract
Bacteria of the Bacillus cereus group colonize several ecological niches and infect different hosts. Bacillus cereus, a ubiquitous species causing food poisoning, Bacillus thuringiensis, an entomopathogen, and Bacillus anthracis, which is highly pathogenic to mammals, are the most important species of this group. These species are closely related genetically, and their specific toxins are encoded by plasmids. The infectious cycle of B. thuringiensis in its insect host is regulated by quorum-sensing systems from the RNPP family. Among them, the Rap-Phr systems, which are well-described in Bacillus subtilis, regulate essential processes, such as sporulation. Given the importance of these systems, we performed a global in silico analysis to investigate their prevalence, distribution, diversity and their role in sporulation in B. cereus group species. The rap-phr genes were identified in all selected strains with 30% located on plasmids, predominantly in B. thuringiensis. Despite a high variability in their sequences, there is a remarkable association between closely related strains and their Rap-Phr profile. Based on the key residues involved in RapH phosphatase activity, we predicted that 32% of the Rap proteins could regulate sporulation by preventing the phosphorylation of Spo0F. These Rap are preferentially located on plasmids and mostly related to B. thuringiensis. The predictions were partially validated by in vivo sporulation experiments suggesting that the residues linked to the phosphatase function are necessary but not sufficient to predict this activity. The wide distribution and diversity of Rap-Phr systems could strictly control the commitment to sporulation and then improve the adaptation capacities of the bacteria to environmental changes.
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Affiliation(s)
- Priscilla de F Cardoso
- Depto. Biologia Geral, Universidade Estadual de Londrina, Londrina, Brazil.,Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Stéphane Perchat
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | | | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
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Buisson C, Gohar M, Huillet E, Nielsen-LeRoux C. Bacillus thuringiensis Spores and Vegetative Bacteria: Infection Capacity and Role of the Virulence Regulon PlcR Following Intrahaemocoel Injection of Galleria mellonella. INSECTS 2019; 10:insects10050129. [PMID: 31060274 PMCID: PMC6571593 DOI: 10.3390/insects10050129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/19/2019] [Accepted: 04/30/2019] [Indexed: 11/16/2022]
Abstract
Bacillus thuringiensis is an invertebrate pathogen that produces insecticidal crystal toxins acting on the intestinal barrier. In the Galleria mellonella larvae infection model, toxins from the PlcR virulence regulon contribute to pathogenicity by the oral route. While B. thuringiensis is principally an oral pathogen, bacteria may also reach the insect haemocoel following injury of the cuticle. Here, we address the question of spore virulence as compared to vegetative cells when the wild-type Bt407cry- strain and its isogenic ∆plcR mutant are inoculated directly into G. mellonella haemocoel. Mortality dose-response curves were constructed at 25 and 37 °C using spores or vegetative cell inocula, and the 50% lethal dose (LD50) in all infection conditions was determined after 48 h of infection. Our findings show that (i) the LD50 is lower for spores than for vegetative cells for both strains, while the temperature has no significant influence, and (ii) the ∆plcR mutant is four to six times less virulent than the wild-type strain in all infection conditions. Our results suggest that the environmental resistant spores are the most infecting form in haemocoel and that the PlcR virulence regulon plays an important role in toxicity when reaching the haemocoel from the cuticle and not only following ingestion.
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Affiliation(s)
- Christophe Buisson
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
| | - Michel Gohar
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
| | - Eugénie Huillet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
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Ehling-Schulz M, Lereclus D, Koehler TM. The Bacillus cereus Group: Bacillus Species with Pathogenic Potential. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0032-2018. [PMID: 31111815 PMCID: PMC6530592 DOI: 10.1128/microbiolspec.gpp3-0032-2018] [Citation(s) in RCA: 235] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Indexed: 12/17/2022] Open
Abstract
The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis, B. cereus, and B. thuringiensis, are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.
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Affiliation(s)
- Monika Ehling-Schulz
- Institute of Microbiology, Department of Pathology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Theresa M Koehler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center - Houston, Houston, TX 77030
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Dubois T, Lemy C, Perchat S, Lereclus D. The signaling peptide NprX controlling sporulation and necrotrophism is imported into Bacillus thuringiensis by two oligopeptide permease systems. Mol Microbiol 2019; 112:219-232. [PMID: 31017318 DOI: 10.1111/mmi.14264] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2019] [Indexed: 11/30/2022]
Abstract
The infectious cycle of Bacillus thuringiensis in the insect host is regulated by quorum sensors of the RNPP family. The activity of these regulators is modulated by their cognate signaling peptides translocated into the bacterial cells by oligopeptide permeases (Opp systems). In B. thuringiensis, the quorum sensor NprR is a bi-functional regulator that connects sporulation to necrotrophism. The binding of the signaling peptide NprX switches NprR from a dimeric inhibitor of sporulation to a tetrameric transcriptional activator involved in the necrotrophic lifestyle of B. thuringiensis. Here, we report that NprX is imported into the bacterial cells by two different oligopeptide permease systems. The first one is Opp, the system known to be involved in the import of the signaling peptide PapR in B. thuringiensis and Bacillus cereus. The second, designated as Npp (NprX peptide permease), was not previously described. We show that at least two substrate binding proteins (SBPs) are able to translocate NprX through OppBCDF. In contrast, we demonstrate that a unique SBP (NppA) can translocate NprX through NppDFBC. We identified the promoter of the npp operon, and we showed that transcription starts at the onset of stationary phase and is repressed by the nutritional regulator CodY during the exponential growth phase.
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Affiliation(s)
- Thomas Dubois
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Christelle Lemy
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Stéphane Perchat
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
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Wan L, Lin J, Du H, Zhang Y, Bravo A, Soberón M, Sun M, Peng D. Bacillus thuringiensistargets the host intestinal epithelial junctions for successful infection ofCaenorhabditis elegans. Environ Microbiol 2019; 21:1086-1098. [DOI: 10.1111/1462-2920.14528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/02/2018] [Accepted: 12/12/2018] [Indexed: 01/28/2023]
Affiliation(s)
- Liting Wan
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Jian Lin
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Hongwen Du
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Yulan Zhang
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Alejandra Bravo
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Mario Soberón
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Ming Sun
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Donghai Peng
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
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Tharsius Raja WR, Antony S, Pachaiyappan S, Amalraj J, Narasimhan P, Keduki B, Veeramuthu D, Perumal P, Savarimuthu I. Antibacterial Activity study of Musizin isolated from Rhamnus wightii Wight and Arn. Bioinformation 2018; 14:511-520. [PMID: 31223211 PMCID: PMC6563663 DOI: 10.6026/97320630014511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 11/27/2022] Open
Abstract
The crude extracts and the compounds isolated from traditional medicinal plants are used to treat infectious diseases caused by bacteria, fungi, and viruses. An attempt has been made in the present investigation to evaluate the antibacterial activity of musizin isolated from Rhamnus wightii, (Family: Rhamnaceae) against Gram-positive (Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis), and Gramnegative (Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa) bacteria. The tested compound showed more pronounced antibacterial activity against the tested pathogens than the standard antibiotics like streptomycin and gentamycin with the lowest minimum inhibitory concentration (MIC). Molecular docking analysis was performed to study the effectiveness of musizin compared to the standard antibiotics; it showed a significant interaction with the target proteins such asalgR (P. arginosa), divIVA (E. faecalis), icaA (S. aureus), plcR(B. cereus), treC (K. pneumonia) and ftsl (E. coli) and found that musizin showed higher potential with least binding energy. It has also been found that musizin had better ADMET properties than the standard drugs. Thus,musizin acts as an inhibitor of bacterial growth for consideration as a drug to treat bacterial infections.
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Affiliation(s)
| | - Stalin Antony
- 2Division of Bioinformatics,Entomology Research Institute, Loyola College, Chennai
- Centre of Advanced Studies in Botany and Centre for Herbal Sciences,University of Madras, Guindy Campus, Chennai 600 025, India
| | | | - Jackson Amalraj
- Division of Microbiology, Entomology Research Institute, LoyolaCollege, Chennai - Chennai
| | - Poorva Narasimhan
- Centre of Advanced Studies in Botany and Centre for Herbal Sciences,University of Madras, Guindy Campus, Chennai 600 025, India
| | - Balakrishna Keduki
- Division of Ethnopharmacology, Entomology Research Institute, Loyola College, Chennai
| | - Duraipandiyan Veeramuthu
- Division of Microbiology, Entomology Research Institute, LoyolaCollege, Chennai - Chennai
- Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies Collegeof Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Palani Perumal
- Centre of Advanced Studies in Botany and Centre for Herbal Sciences,University of Madras, Guindy Campus, Chennai 600 025, India
| | - Ignacimuthu Savarimuthu
- Division of Ethnopharmacology, Entomology Research Institute, Loyola College, Chennai
- International Scientific Partnership Program, King Saud University, PostBox 2455, Riyadh 1011 11451, Kingdom of Saudi Arabia
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Yehuda A, Slamti L, Bochnik-Tamir R, Malach E, Lereclus D, Hayouka Z. Turning off Bacillus cereus quorum sensing system with peptidic analogs. Chem Commun (Camb) 2018; 54:9777-9780. [PMID: 30105347 DOI: 10.1039/c8cc05496g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We explored quenching of the PlcR-PapR quorum-sensing system in Bacillus cereus. We generated PapR7-peptidic derivatives that inhibit this system and thus the production of virulence factors, reflected by a loss in hemolytic activity, without affecting bacterial growth. To our knowledge, these peptides represent the first potent synthetic inhibitors of quorum-sensing in B. cereus.
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Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
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Fu Y, Yu Z, Liu S, Chen B, Zhu L, Li Z, Chou SH, He J. c-di-GMP Regulates Various Phenotypes and Insecticidal Activity of Gram-Positive Bacillus thuringiensis. Front Microbiol 2018; 9:45. [PMID: 29487570 PMCID: PMC5816809 DOI: 10.3389/fmicb.2018.00045] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/09/2018] [Indexed: 12/26/2022] Open
Abstract
C-di-GMP has been well investigated to play significant roles in the physiology of many Gram-negative bacteria. However, its effect on Gram-positive bacteria is less known. In order to more understand the c-di-GMP functions in Gram-positive bacteria, we have carried out a detailed study on the c-di-GMP-metabolizing enzymes and their physiological functions in Bacillus thuringiensis, a Gram-positive entomopathogenic bacterium that has been applied as an insecticide successfully. We performed a systematic study on the ten putative c-di-GMP-synthesizing enzyme diguanylate cyclases (DGCs) and c-di-GMP-degrading enzyme phosphodiesterases (PDEs) in B. thuringiensis BMB171, and artificially elevated the intracellular c-di-GMP level in BMB171 by deleting one or more pde genes. We found increasing level of intracellular c-di-GMP exhibits similar activities as those in Gram-negative bacteria, including altered activities in cell motility, biofilm formation, and cell-cell aggregation. Unexpectedly, we additionally found a novel function exhibited by the increasing level of c-di-GMP to promote the insecticidal activity of this bacterium against Helicoverpa armigera. Through whole-genome transcriptome profile analyses, we found that 4.3% of the B. thuringiensis genes were differentially transcribed when c-di-GMP level was increased, and 77.3% of such gene products are involved in some regulatory pathways not reported in other bacteria to date. In summary, our study represents the first comprehensive report on the c-di-GMP-metabolizing enzymes, their effects on phenotypes, and the transcriptome mediated by c-di-GMP in an important Gram-positive bacterium.
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Affiliation(s)
- Yang Fu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhaoqing Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Bo Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Li Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhou Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- NCHU Agricultural Biotechnology Center, Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Ben Rejeb S, Lereclus D, Slamti L. Analysis of abrB Expression during the Infectious Cycle of Bacillus thuringiensis Reveals Population Heterogeneity. Front Microbiol 2017; 8:2471. [PMID: 29312181 PMCID: PMC5732988 DOI: 10.3389/fmicb.2017.02471] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/28/2017] [Indexed: 11/19/2022] Open
Abstract
Using the model host/pathogen pair Galleria mellonella/Bacillus thuringiensis, we have shown that these bacteria could kill their insect host, survive in its cadaver and form spores by sequentially activating virulence, necrotrophism and sporulation genes. However, the population isolated from the cadavers was heterogeneous, including non-sporulating cells in an unknown physiological state. To characterize these bacteria, we used a transcriptional fusion between the promoter of a gene expressed during early exponential growth (abrB) and a reporter gene encoding a destabilized version of GFP, in combination with a fluorescent reporter of the necrotrophic state. The composition of the bacterial population during infection was then analyzed by flow cytometry. We showed that the PabrB promoter was activated in the population that had turned on the necrotrophic reporter, suggesting a re-entry into vegetative growth. Strikingly, the cells that did not go through the necrotrophic state did not activate the PabrB promoter and appear as a dormant subpopulation. We propose a new model describing the B. thuringiensis cell types during infection.
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Affiliation(s)
- Samia Ben Rejeb
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Didier Lereclus
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Leyla Slamti
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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Fazion F, Perchat S, Buisson C, Vilas-Bôas G, Lereclus D. A plasmid-borne Rap-Phr system regulates sporulation ofBacillus thuringiensisin insect larvae. Environ Microbiol 2017; 20:145-155. [DOI: 10.1111/1462-2920.13946] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/28/2017] [Accepted: 09/23/2017] [Indexed: 10/18/2022]
Affiliation(s)
- Fernanda Fazion
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay; 78350 Jouy-en-Josas France
- Universidade Estadual de Londrina, Bio/CCB; Londrina Brazil
| | - Stéphane Perchat
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay; 78350 Jouy-en-Josas France
| | - Christophe Buisson
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay; 78350 Jouy-en-Josas France
| | | | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay; 78350 Jouy-en-Josas France
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Gauvry E, Mathot AG, Leguérinel I, Couvert O, Postollec F, Broussolle V, Coroller L. Knowledge of the physiology of spore-forming bacteria can explain the origin of spores in the food environment. Res Microbiol 2017; 168:369-378. [DOI: 10.1016/j.resmic.2016.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 07/22/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
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Duport C, Jobin M, Schmitt P. Adaptation in Bacillus cereus: From Stress to Disease. Front Microbiol 2016; 7:1550. [PMID: 27757102 PMCID: PMC5047918 DOI: 10.3389/fmicb.2016.01550] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/15/2016] [Indexed: 12/23/2022] Open
Abstract
Bacillus cereus is a food-borne pathogen that causes diarrheal disease in humans. After ingestion, B. cereus experiences in the human gastro-intestinal tract abiotic physical variables encountered in food, such as acidic pH in the stomach and changing oxygen conditions in the human intestine. B. cereus responds to environmental changing conditions (stress) by reversibly adjusting its physiology to maximize resource utilization while maintaining structural and genetic integrity by repairing and minimizing damage to cellular infrastructure. As reviewed in this article, B. cereus adapts to acidic pH and changing oxygen conditions through diverse regulatory mechanisms and then exploits its metabolic flexibility to grow and produce enterotoxins. We then focus on the intricate link between metabolism, redox homeostasis, and enterotoxins, which are recognized as important contributors of food-borne disease.
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Affiliation(s)
- Catherine Duport
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
| | - Michel Jobin
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
| | - Philippe Schmitt
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
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Perchat S, Talagas A, Poncet S, Lazar N, Li de la Sierra-Gallay I, Gohar M, Lereclus D, Nessler S. How Quorum Sensing Connects Sporulation to Necrotrophism in Bacillus thuringiensis. PLoS Pathog 2016; 12:e1005779. [PMID: 27483473 PMCID: PMC4970707 DOI: 10.1371/journal.ppat.1005779] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 06/29/2016] [Indexed: 11/28/2022] Open
Abstract
Bacteria use quorum sensing to coordinate adaptation properties, cell fate or commitment to sporulation. The infectious cycle of Bacillus thuringiensis in the insect host is a powerful model to investigate the role of quorum sensing in natural conditions. It is tuned by communication systems regulators belonging to the RNPP family and directly regulated by re-internalized signaling peptides. One such RNPP regulator, NprR, acts in the presence of its cognate signaling peptide NprX as a transcription factor, regulating a set of genes involved in the survival of these bacteria in the insect cadaver. Here, we demonstrate that, in the absence of NprX and independently of its transcriptional activator function, NprR negatively controls sporulation. NprR inhibits expression of Spo0A-regulated genes by preventing the KinA-dependent phosphorylation of the phosphotransferase Spo0F, thus delaying initiation of the sporulation process. This NprR function displays striking similarities with the Rap proteins, which also belong to the RNPP family, but are devoid of DNA-binding domain and indirectly control gene expression via protein-protein interactions in Bacilli. Conservation of the Rap residues directly interacting with Spo0F further suggests a common inhibition of the sporulation phosphorelay. The crystal structure of apo NprR confirms that NprR displays a highly flexible Rap-like structure. We propose a molecular regulatory mechanism in which key residues of the bifunctional regulator NprR are directly and alternatively involved in its two functions. NprX binding switches NprR from a dimeric inhibitor of sporulation to a tetrameric transcriptional activator involved in the necrotrophic lifestyle of B. thuringiensis. NprR thus tightly coordinates sporulation and necrotrophism, ensuring survival and dissemination of the bacteria during host infection. Bacillus thuringiensis is an entomopathogenic bacterium used worldwide as biopesticide. Its life cycle in insect larvae, which includes virulence, necrotrophism and sporulation, is regulated by cell-cell communication systems involving sensor proteins directly regulated by re-internalized peptide pheromones. After toxaemia caused by pore-forming Cry toxins, the PlcR sensor activates the production of virulence factors leading to insect death. B. thuringiensis then shifts to a necrotrophic lifestyle preceding sporulation. Previously, we showed that this process is regulated by the sensor NprR, which, in the presence of its cognate signaling peptide NprX, adopts a tetrameric conformation allowing its binding to specific DNA sequences and transcription of genes involved in survival of the bacteria in insect cadavers. Here, we demonstrate that, in the absence of NprX, NprR is a dimer, which negatively controls sporulation, independently of its transcription factor activity. We show that NprR prevents the phosphorylation of the phosphoprotein Spo0F and inhibits the phosphorylation cascade regulating sporulation. This demonstrates that NprX binding switches the bifunctional sensor NprR from a dimeric sporulation inhibitor to a tetrameric transcription factor. By establishing a close coordination between cell density, necrotrophism and sporulation, this communication system benefits a pathogenic bacterium feeding on death matter like B. thuringiensis. NprR is found in all strains of the B. cereus group, including B. anthracis and B. cereus involved in food poisoning. Our results may provide new insights for controlling the development and the survival of these undesirable bacteria.
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Affiliation(s)
- Stéphane Perchat
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Antoine Talagas
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Sandrine Poncet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Noureddine Lazar
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Inès Li de la Sierra-Gallay
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Michel Gohar
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
- * E-mail: (DL); (SN)
| | - Sylvie Nessler
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
- * E-mail: (DL); (SN)
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47
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Do H, Kumaraswami M. Structural Mechanisms of Peptide Recognition and Allosteric Modulation of Gene Regulation by the RRNPP Family of Quorum-Sensing Regulators. J Mol Biol 2016; 428:2793-804. [PMID: 27283781 DOI: 10.1016/j.jmb.2016.05.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/19/2016] [Accepted: 05/29/2016] [Indexed: 11/19/2022]
Abstract
The members of RRNPP family of bacterial regulators sense population density-specific secreted oligopeptides and modulate the expression of genes involved in cellular processes, such as sporulation, competence, virulence, biofilm formation, conjugative plasmid transfer and antibiotic resistance. Signaling by RRNPP regulators include several steps: generation and secretion of the signaling oligopeptides, re-internalization of the signaling molecules into the cytoplasm, signal sensing by the cytosolic RRNPP regulators, signal-specific allosteric structural changes in the regulators, and interaction of the regulators with their respective regulatory target and gene regulation. The recently determined structures of the RRNPP regulators provide insight into the mechanistic aspects for several steps in this signaling circuit. In this review, we discuss the structural principles underlying peptide specificity, regulatory target recognition, and ligand-induced allostery in RRNPP regulators and its impact on gene regulation. Despite the conserved tertiary structure of these regulators, structural analyses revealed unexpected diversity in the mechanism of activation and molecular strategies that couple the peptide-induced allostery to gene regulation. Although these structural studies provide a sophisticated understanding of gene regulation by RRNPP regulators, much needs to be learned regarding the target DNA binding by yet-to-be characterized RNPP regulators and the several aspects of signaling by Rgg regulators.
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Affiliation(s)
- Hackwon Do
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Hospital Research Institute, and Department of Pathology and Genomic Medicine, Houston Methodist Hospital System, Houston, TX, 77030, USA
| | - Muthiah Kumaraswami
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Hospital Research Institute, and Department of Pathology and Genomic Medicine, Houston Methodist Hospital System, Houston, TX, 77030, USA.
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48
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Fagerlund A, Smith V, Røhr ÅK, Lindbäck T, Parmer MP, Andersson KK, Reubsaet L, Økstad OA. Cyclic diguanylate regulation of Bacillus cereus group biofilm formation. Mol Microbiol 2016; 101:471-94. [PMID: 27116468 DOI: 10.1111/mmi.13405] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2016] [Indexed: 12/30/2022]
Abstract
Biofilm formation can be considered a bacterial virulence mechanism. In a range of Gram-negatives, increased levels of the second messenger cyclic diguanylate (c-di-GMP) promotes biofilm formation and reduces motility. Other bacterial processes known to be regulated by c-di-GMP include cell division, differentiation and virulence. Among Gram-positive bacteria, where the function of c-di-GMP signalling is less well characterized, c-di-GMP was reported to regulate swarming motility in Bacillus subtilis while having very limited or no effect on biofilm formation. In contrast, we show that in the Bacillus cereus group c-di-GMP signalling is linked to biofilm formation, and to several other phenotypes important to the lifestyle of these bacteria. The Bacillus thuringiensis 407 genome encodes eleven predicted proteins containing domains (GGDEF/EAL) related to c-di-GMP synthesis or breakdown, ten of which are conserved through the majority of clades of the B. cereus group, including Bacillus anthracis. Several of the genes were shown to affect biofilm formation, motility, enterotoxin synthesis and/or sporulation. Among these, cdgF appeared to encode a master diguanylate cyclase essential for biofilm formation in an oxygenated environment. Only two cdg genes (cdgA, cdgJ) had orthologs in B. subtilis, highlighting differences in c-di-GMP signalling between B. subtilis and B. cereus group bacteria.
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Affiliation(s)
- Annette Fagerlund
- Laboratory for Microbial Dynamics (LaMDa), Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PB1068, Oslo, 0316, Norway
| | - Veronika Smith
- Laboratory for Microbial Dynamics (LaMDa), Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PB1068, Oslo, 0316, Norway.,Centre for Integrative Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
| | - Åsmund K Røhr
- Department of Biosciences, University of Oslo, PB1066, Oslo, 0316, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, PB8146 Dep, Oslo, 0033, Norway
| | - Marthe P Parmer
- Bioanalytics, Section for Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, PB1068, Oslo, 0316, Norway
| | | | - Leon Reubsaet
- Bioanalytics, Section for Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, PB1068, Oslo, 0316, Norway
| | - Ole Andreas Økstad
- Laboratory for Microbial Dynamics (LaMDa), Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PB1068, Oslo, 0316, Norway.,Centre for Integrative Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
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49
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Perez-Pascual D, Monnet V, Gardan R. Bacterial Cell-Cell Communication in the Host via RRNPP Peptide-Binding Regulators. Front Microbiol 2016; 7:706. [PMID: 27242728 PMCID: PMC4873490 DOI: 10.3389/fmicb.2016.00706] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/28/2016] [Indexed: 12/23/2022] Open
Abstract
Human microbiomes are composed of complex and dense bacterial consortia. In these environments, bacteria are able to react quickly to change by coordinating their gene expression at the population level via small signaling molecules. In Gram-positive bacteria, cell–cell communication is mostly mediated by peptides that are released into the extracellular environment. Cell–cell communication based on these peptides is especially widespread in the group Firmicutes, in which they regulate a wide array of biological processes, including functions related to host–microbe interactions. Among the different agents of communication, the RRNPP family of cytoplasmic transcriptional regulators, together with their cognate re-internalized signaling peptides, represents a group of emerging importance. RRNPP members that have been studied so far are found mainly in species of bacilli, streptococci, and enterococci. These bacteria are characterized as both human commensal and pathogenic, and share different niches in the human body with other microorganisms. The goal of this mini-review is to present the current state of research on the biological relevance of RRNPP mechanisms in the context of the host, highlighting their specific roles in commensalism or virulence.
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Affiliation(s)
- David Perez-Pascual
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas France
| | - Véronique Monnet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas France
| | - Rozenn Gardan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas France
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50
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Martin-Verstraete I, Peltier J, Dupuy B. The Regulatory Networks That Control Clostridium difficile Toxin Synthesis. Toxins (Basel) 2016; 8:E153. [PMID: 27187475 PMCID: PMC4885068 DOI: 10.3390/toxins8050153] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/03/2016] [Accepted: 05/05/2016] [Indexed: 12/19/2022] Open
Abstract
The pathogenic clostridia cause many human and animal diseases, which typically arise as a consequence of the production of potent exotoxins. Among the enterotoxic clostridia, Clostridium difficile is the main causative agent of nosocomial intestinal infections in adults with a compromised gut microbiota caused by antibiotic treatment. The symptoms of C. difficile infection are essentially caused by the production of two exotoxins: TcdA and TcdB. Moreover, for severe forms of disease, the spectrum of diseases caused by C. difficile has also been correlated to the levels of toxins that are produced during host infection. This observation strengthened the idea that the regulation of toxin synthesis is an important part of C. difficile pathogenesis. This review summarizes our current knowledge about the regulators and sigma factors that have been reported to control toxin gene expression in response to several environmental signals and stresses, including the availability of certain carbon sources and amino acids, or to signaling molecules, such as the autoinducing peptides of quorum sensing systems. The overlapping regulation of key metabolic pathways and toxin synthesis strongly suggests that toxin production is a complex response that is triggered by bacteria in response to particular states of nutrient availability during infection.
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Affiliation(s)
- Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
- UFR Sciences du vivant, University Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris 75015, France.
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
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