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Xu G, Wang Z, Bai Y, Crickmore N, Wang K, Hassen AI, Geng L, Shu C, Zhang J. Identification of a biomarker for Bacillus thuringiensis strains with high toxicity against Spodoptera frugiperda based on insecticidal gene linkage analysis. PEST MANAGEMENT SCIENCE 2024. [PMID: 38940437 DOI: 10.1002/ps.8276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/29/2024]
Abstract
BACKGROUND Bacillus thuringiensis (Bt) is a Gram-positive bacterium that produces various insecticidal proteins used to control insect pests. Spodoptera frugiperda is a global insect pest which causes serious damage to crops, but bio-insecticides currently available to control this pest have limited activity and so new ones are always being sought. In this study we have tested the hypothesis that a biomarker for strain toxicity could be found that would greatly facilitate the identification of new potential products. RESULTS Using genomic sequencing data we constructed a linkage network of insecticidal genes from 1957 Bt genomes and found that four gene families, namely cry1A, cry1I, cry2A and vip3A, showed strong linkage. For 95 strains isolated from soil samples we assayed them for toxicity towards S. frugiperda and for the presence of the above gene families. All of the strains that showed high toxicity also contained a member of the vip3A gene family. Two of them were more toxic than a commercially available strain and genomic sequencing identified a number of potentially novel toxin-encoding genes. CONCLUSIONS The presence of a vip3A gene in the genome of a Bt strain proved to be a strong indicator of toxicity towards S. frugiperda validating this biomarker approach as a strategy for future discovery programs. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Guoli Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Zeyu Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuqi Bai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Neil Crickmore
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Kui Wang
- School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Ahmed Idris Hassen
- Agricultural Research Council-Plant Health and Protection, Pretoria, South Africa
| | - Lili Geng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Changlong Shu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Plant Protection, Anhui Agricultural University, Hefei, China
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2
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Barla RJ, Raghuvanshi S, Gupta S. Reforming CO 2 bio-mitigation utilizing Bacillus cereus from hypersaline realms in pilot-scale bubble column bioreactor. Sci Rep 2024; 14:6354. [PMID: 38491100 PMCID: PMC10943127 DOI: 10.1038/s41598-024-56965-8] [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: 01/19/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024] Open
Abstract
The bubble column reactor of 10 and 20 L capacity was designed to bio-mitigate 10% CO2 (g) with 90% air utilizing thermophilic bacteria (Bacillus cereus SSLMC2). The maximum biomass yield during the growth phase was obtained as 9.14 and 10.78 g L-1 for 10 and 20 L capacity, respectively. The maximum removal efficiency for CO2 (g) was obtained as 56% and 85% for the 10 and 20 L reactors, respectively. The FT-IR and GC-MS examination of the extracellular and intracellular samples identified value-added products such as carboxylic acid, fatty alcohols, and hydrocarbons produced during the process. The total carbon balance for CO2 utilization in different forms confirmed that B. cereus SSLMC2 utilized 1646.54 g C in 10 L and 1587 g of C in 20 L reactor out of 1696.13 g of total carbon feed. The techno-economic assessment established that the capital investment required was $286.21 and $289.08 per reactor run of 11 days and $0.167 and $0.187 per gram of carbon treated for 10 and 20 L reactors, respectively. The possible mechanism pathways for bio-mitigating CO2 (g) by B. cereus SSLMC2 were also presented utilizing the energy reactions. Hence, the work presents the novelty of utilizing thermophilic bacteria and a bubble column bioreactor for CO2 (g) bio-mitigation.
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Affiliation(s)
- Rachael J Barla
- Faculty Division-1, Department of Chemical Engineering, Birla Institute of Technology and Science (BITS), BITS PILANI, Pilani, 333031, Rajasthan, India
| | - Smita Raghuvanshi
- Faculty Division-1, Department of Chemical Engineering, Birla Institute of Technology and Science (BITS), BITS PILANI, Pilani, 333031, Rajasthan, India.
| | - Suresh Gupta
- Faculty Division-1, Department of Chemical Engineering, Birla Institute of Technology and Science (BITS), BITS PILANI, Pilani, 333031, Rajasthan, India
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3
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Carlsen ECL, Hjelset S, Gomes T, Igartua A, Sørensen L, Booth AM, Hylland K, Eiler A. Synthetic and natural rubber associated chemicals drive functional and structural changes as well as adaptations to antibiotics in in vitro marine microbiomes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 273:116134. [PMID: 38387143 DOI: 10.1016/j.ecoenv.2024.116134] [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: 10/13/2023] [Revised: 02/06/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
The leaching of additives from plastics and elastomers (rubbers) has raised concerns due to their potential negative impacts on the environment and the development of antibiotic resistance. In this study, we investigated the effects of chemicals extracted from two types of rubber on microbiomes derived from a benthic sea urchin and two pelagic fish species. Additionally, we examined whether bacterial communities preconditioned with rubber-associated chemicals displayed adaptations to antibiotics. At the highest tested concentrations of chemicals, we observed reduced maximum growth rates and yields, prolonged lag phases, and increased alpha diversity. While the effects on alpha and beta diversity were not always conclusive, several bacterial genera were significantly influenced by chemicals from the two rubber sources. Subsequent exposure of sea urchin microbiomes preconditioned with rubber chemicals to the antibiotic ciprofloxacin resulted in decreased maximum growth rates. This indicates a more sensitive microbiome to ciprofloxacin when preconditioned with rubber chemicals. Although no significant interaction effects between rubber chemicals and ciprofloxacin exposure were observed in bacterial alpha and beta diversity, we observed log-fold changes in two bacterial genera in response to ciprofloxacin exposure. These findings highlight the structural and functional alterations in microbiomes originating from various marine species when exposed to rubber-associated chemicals and underscore the potential risks posed to marine life.
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Affiliation(s)
- Eira Catharine Lødrup Carlsen
- Section for Aquatic Biology and Toxicology, Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Blindernveien 31, Oslo 0371, Norway
| | - Sverre Hjelset
- Section for Aquatic Biology and Toxicology, Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Blindernveien 31, Oslo 0371, Norway; Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Økernveien 94, Oslo 0579, Norway
| | - Tânia Gomes
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Økernveien 94, Oslo 0579, Norway
| | - Amaia Igartua
- Department of Climate and Environment, SINTEF Ocean, SINTEF Sealab, Brattørkaia 17C, Trondheim 7010, Norway
| | - Lisbet Sørensen
- Department of Climate and Environment, SINTEF Ocean, SINTEF Sealab, Brattørkaia 17C, Trondheim 7010, Norway
| | - Andy M Booth
- Department of Climate and Environment, SINTEF Ocean, SINTEF Sealab, Brattørkaia 17C, Trondheim 7010, Norway
| | - Ketil Hylland
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Blindernveien 31, Oslo 0371, Norway
| | - Alexander Eiler
- Section for Aquatic Biology and Toxicology, Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Blindernveien 31, Oslo 0371, Norway.
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4
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Jia B, Wan J, Liu H, Yan B, Zhang L, Su X. DIET-like and MIET-like mutualism of S. oneidensis MR-1 and metal-reducing function microflora boosts Cr(VI) reduction. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133401. [PMID: 38171202 DOI: 10.1016/j.jhazmat.2023.133401] [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: 11/15/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024]
Abstract
Microbial treatment of Cr(VI) is an environmentally friendly and low-cost approach. However, the mechanism of mutualism and the role of interspecies electron transfer in Cr(VI) reducing microflora are unclear. Herein, we constructed an intersymbiotic microbial association flora to augment interspecies electron transfer via functionalizing electroactive Shewanella oneidensis MR-1 with metal-reducing microflora, and thus the efficiency of Cr(VI) reduction. The findings suggest that the metal-reducing active microflora could converts glucose into lactic acid and riboflavin for S. oneidensis MR-1 to act as a carbon source and electron mediator. Thus, when adding initial 25 mg/L Cr (VI), this microflora exhibited an outstanding Cr (VI) removal efficiency (100%) at 12 h and elevated Cr (III) immobilization efficiency (80%) at 60 h with the assistance of 25 mg/L Cu(II). A series of electrochemical experiments proved this remarkable removal efficiency were ascribed to the improved interspecies electron transfer efficiency through direct interspecies electron transfer and riboflavin through mediated interspecies electron transfer. Furthermore, the metagenomic analysis revealed the expression level of the electron transport pathway was promoted. Intriguing high abundance of genes participating in the bio-reduction and biotransformation of Cr(VI) was also observed in functional microflora. These outcomes give a novel strategy for enhancing the reduction and fixation of harmful heavy metals by coculturing function microflora with electrogenic microorganisms.
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Affiliation(s)
- Boyu Jia
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Juanjuan Wan
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Hui Liu
- Huadian Coal Industry Group Co., Ltd, Beijing 100035, China
| | - Bo Yan
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Lijuan Zhang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
| | - Xintai Su
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China.
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5
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Alves GB, Lemes TSO, Pereira EJG, Jurat-Fuentes JL, Smagghe G, Santos GR, Haddi K, Corrêa RFT, Melo FL, Jumbo LOV, Oliveira EE, Peron AJ, Ribeiro BM, Aguiar RWS. Draft genome of neotropical Bacillus thuringiensis UFT038 and its potential against lepidopteran soybean pests. Folia Microbiol (Praha) 2024; 69:91-99. [PMID: 38017300 DOI: 10.1007/s12223-023-01114-3] [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: 06/14/2023] [Accepted: 11/15/2023] [Indexed: 11/30/2023]
Abstract
Bacillus thuringiensis (Bt) is known for its Cry and Vip3A pesticidal proteins with high selectivity to target pests. Here, we assessed the potential of a novel neotropical Bt strain (UFT038) against six lepidopteran pests, including two Cry-resistant populations of fall armyworm, Spodoptera frugiperda. We also sequenced and analyzed the genome of Bt UFT038 to identify genes involved in insecticidal activities or encoding other virulence factors. In toxicological bioassays, Bt UFT038 killed and inhibited the neonate growth in a concentration-dependent manner. Bt UFT038 and HD-1 were equally toxic against S. cosmioides, S. frugiperda (S_Bt and R_Cry1 + 2Ab populations), Helicoverpa zea, and H. armigera. However, larval growth inhibition results indicated that Bt UFT038 was more toxic than HD-1 to S. cosmioides, while HD-1 was more active against Chrysodeixis includens. The draft genome of Bt UFT038 showed the cry1Aa8, cry1Ac11, cry1Ia44, cry2Aa9, cry2Ab35, and vip3Af5 genes. Besides this, genes encoding the virulence factors (inhA, plcA, piplC, sph, and chi1-2) and toxins (alo, cytK, hlyIII, hblA-D, and nheA-C) were also identified. Collectively, our findings reveal the potential of the Bt UFT038 strain as a source of insecticidal genes against lepidopteran pests, including S. cosmioides and S. frugiperda.
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Affiliation(s)
- Giselly B Alves
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Timóteo S O Lemes
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Eliseu J G Pereira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Juan L Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Gil R Santos
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Khalid Haddi
- Departamento de Entomologia, Universidade Federal de Lavras, Lavras, MG, 37200-900, Brazil
| | - Roberto F T Corrêa
- Departamento de Biologia Celular, Universidade de Brasília, Brasília, DF, 70910-900, Brazil
| | - Fernando L Melo
- Departamento de Biologia Celular, Universidade de Brasília, Brasília, DF, 70910-900, Brazil
| | - Luis O Viteri Jumbo
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
- Carrera de Agronomía, Universidad Nacional de Loja (UNL), Loja, 110103, Ecuador
| | - Eugenio E Oliveira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Antônio J Peron
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Bergmann M Ribeiro
- Departamento de Biologia Celular, Universidade de Brasília, Brasília, DF, 70910-900, Brazil
| | - Raimundo W S Aguiar
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil.
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6
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El Bestawy E, El-Hameed ASA, Fadl E. Desalination of seawater using integrated microbial biofilm/cellulose acetate membrane and silver NPs/activated carbon nanocomposite in a continuous mode. Sci Rep 2024; 14:274. [PMID: 38168504 PMCID: PMC10762133 DOI: 10.1038/s41598-023-50311-0] [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: 08/17/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
The main objective of the present study was to desalinate seawater using Bacillus cereus gravel biofilm and cellulose acetate (CA) membranes with and without silver nanoparticles (AgNPs) as a potent and safe disinfectant for the treated water. Six desalination trials (I, II, III, IV, V and VI) were performed using the proposed biofilm/cellulose membrane. Results confirmed that Bacillus cereus gravel biofilm (microbial desalination) is the optimal system for desalination of seawater. It could achieve 45.0% RE (initial salinity: 44,478 mg/L), after only 3 h compared to the other tested treatments. It could also achieve 42, 42, 57, 43 and 59% RE for TDS, EC, TSS, COD and BOD, respectively. To overcome the problem of the residual salinity and reach complete elimination of salt content for potential reuse, multiple units of the proposed biofilm can be used in sequence. As a general conclusion, the Bacillus cereus biofilm system can be considered as remarkably efficient, feasible, rapid, clean, renewable, durable, environmentally friendly and easily applied technology compared to the very costly and complicated common desalination technologies. Up to our knowledge, this is the first time microbial biofilm was developed and used as an effective system for seawater desalination.
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Affiliation(s)
- Ebtesam El Bestawy
- Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt.
| | - Adel Salah Abd El-Hameed
- Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt
| | - Eman Fadl
- Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt
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7
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Liu J, Cui T. Expression, Characterisation, Homology Modelling and Molecular Docking of a Novel M17 Family Leucyl-Aminopeptidase from Bacillus cereus CZ. Int J Mol Sci 2023; 24:15939. [PMID: 37958921 PMCID: PMC10649214 DOI: 10.3390/ijms242115939] [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: 09/28/2023] [Revised: 10/27/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Leucyl-aminopeptidase (LAP), an important metallopeptidase, hydrolyses amino acid residues from the N-terminus of polypeptides and proteins, acting preferentially on the peptide bond formed by N-terminus leucine. A new leucyl-aminopeptidase was found in Bacillus cereus CZ. Its gene (bclap) contained a 1485 bp ORF encoding 494 amino acids with a molecular weight of 54 kDa. The bcLAP protein was successfully expressed in E. coli BL21(DE3). Optimal activity is obtained at pH 9.0 and 58 °C. The bcLAP displays a moderate thermostability and an alkaline pH adaptation range. Enzymatic activity is dramatically enhanced by Ni2+. EDTA significantly inhibits the enzymatic activity, and bestatin and SDS also show strong inhibition. The three-dimensional model of bcLAP monomer and homohexamer is simulated byPHYRE2 server and SWISS-MODEL server. The docking of bestatin, Leu-Trp, Asp-Trp and Ala-Ala-Gly to bcLAP is performed using AutoDock4.2.5, respectively. Molecular docking results show that the residues Lys260, Asp265, Lys272, Asp283, Asp342, Glu344, Arg346, Gly372 and His437 are involved in the hydrogen bonding with the ligands and zinc ions. There may be two nucleophilic catalytic mechanisms in bcLAP, one involving His 437 or Arg346 and the other involving His437 and Arg346. The bcLAP can hydrolyse the peptide bonds in Leu-Trp, Asp-Trp and Ala-Ala-Gly.
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Affiliation(s)
| | - Tangbing Cui
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China;
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8
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More's the Same-Multiple Hosts Do Not Select for Broader Host Range Phages. Viruses 2023; 15:v15020518. [PMID: 36851732 PMCID: PMC9960766 DOI: 10.3390/v15020518] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/15/2023] Open
Abstract
Bacteriophage host range is a result of the interactions between phages and their hosts. For phage therapy, phages with a broader host range are desired so that a phage can infect and kill the broadest range of pathogen strains or related species possible. A common, but not well-tested, belief is that using multiple hosts during the phage isolation will make the isolation of broader host range phage more likely. Using a Bacillus cereus group system, we compared the host ranges of phages isolated on one or four hosts and found that there was no difference in the breadth of host ranges of the isolated phages. Both narrow and broader host range phage were also equally likely to be isolated from either isolation procedure. While there are methods that reliably isolate broader host range phages, such as sequential host isolation, and there are other reasons to use multiple hosts during isolation, multiple hosts are not a consistent way to obtain broader host range phages.
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Meng L, Zhang R, Dong L, Hu H, Liu H, Zheng N, Wang J, Cheng J. Characterization and spoilage potential of Bacillus cereus isolated from farm environment and raw milk. Front Microbiol 2022; 13:940611. [PMID: 36177462 PMCID: PMC9514233 DOI: 10.3389/fmicb.2022.940611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Bacillus cereus sensu lato (B. cereus sl) is important spoilage bacteria causing milk structure and flavor changes and is ubiquitous in the environment. This study addresses the biodiversity, toxicity, and proteolytic activity of B. cereus sl from 82 environmental samples and 18 raw bovine milk samples from a dairy farm in the region of Tianjin. In sum, 47 B. cereus sl isolates were characterized through biochemical tests, 16S rRNA gene sequencing, and panC gene analysis. Fourteen sequence types (STs) of B. cereus sl were found in raw bovine milk samples, and five new STs (ST2749, ST2750, ST2751, ST2752, and ST2753) were identified in this study. ST1150 was the dominant ST, associated with fecal, air, drinking water, teat skin, teat cup, and teat dip cup. The results of toxin gene analyses showed that 12.77% and 8.51% of isolates carried hblACD and nheABC operons, respectively. In addition, the detection rate of emetic cesB gene was 21.28%. B. cereus sl demonstrated high spoilage potentials even at 7°C, which has the proteolytic activity of 14.32 ± 1.96 μmol of glycine equivalents per ml. Proteolytic activities were significantly (p < 0.05) decreased after the heat treatment. The residual activity of protease produced at 7°C was significantly higher than that produced at 25°C and 37°C after treatment at 121°C for 10 s and 135°C for 5 s (p < 0.01). Together, the results provide insights into the characteristics of B. cereus sl from farm environment and raw bovine milk and revealed that B. cereus sl contamination should also be monitored in raw milk for ultra-high temperature (UHT) products. This knowledge illustrates that strict cleaning management should be implemented to control B. cereus sl and assure high-quality milk products.
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Affiliation(s)
- Lu Meng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ruirui Zhang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
| | - Lei Dong
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Precision Livestock and Nutrition Laboratory, Teaching and Research Centre (TERRA), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Haiyan Hu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huimin Liu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Nan Zheng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaqi Wang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Jiaqi Wang
| | - Jianbo Cheng
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
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10
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Malinga LN, Laing MD. Efficacy of Biopesticides in the Management of the Cotton Bollworm, Helicoverpa armigera (Noctuidae), under Field Conditions. INSECTS 2022; 13:insects13080673. [PMID: 35893028 PMCID: PMC9332838 DOI: 10.3390/insects13080673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022]
Abstract
Simple Summary Cotton remains the most important cash crop in the world. The key insect pests of cotton include the African bollworm Helicoverpa armigera. This pest causes damage to crops estimated at greater than USD 2 billion per year worldwide. Excessive use of insecticides to control this pest has a negative effect on the environment, and is expensive for the farmers. The aim of this study is to explore the field efficacy of different biopesticides as an alternative to control H. armigera. Four biopesticides—namely, Eco-Bb® (Beauveria bassiana), Bb endophyte (Beauveria bassiana), Bolldex® (nucleopolyhedrovirus), and Delfin® (Bacillus thuringiensis)—were evaluated and compared with the pyrethroid Karate® (lambda-cyhalothrin) and an untreated control. Plots treated with Karate® had significantly lower numbers of H. armigera larvae compared to the untreated control, and were comparable to the plots treated with Bolldex®. On average, plots treated with Bolldex® had a high seed cotton yield compared to the other treatments. Biopesticides showed a moderate reduction in the numbers of H. armigera larvae, and could thus be used within an integrated pest management programme. Abstract Cotton is one of the most valuable materials in the world, popularly used in the clothing industry and other products. However, its production is limited by the high infestation of insect pests. A study was conducted to evaluate the effects of different biopesticides on the control of the African bollworm (Helicoverpa armigera) under cotton field conditions. Four biopesticides—namely, Eco-Bb® (Beauveria bassiana), Bb endophyte (Beauveria bassiana), Bolldex® (Nucleopolyhedrovirus), and Delfin® (Bacillus thuringiensis)—were evaluated and compared with the pyrethroid Karate® (lambda-cyhalothrin) and an untreated control against H. armigera. Field trials were conducted at the Agriculture Research Council, Rustenburg, in the North West Province of South Africa during the 2017 and 2018 cotton seasons. The results revealed that in plots sprayed with Karate® and Bolldex®, the numbers of H. armigera were significantly reduced compared to the untreated controls. Plots treated with Bolldex® had the lowest number of damaged bolls in 2017, while those treated with Karate® had the lowest number of damaged bolls in 2018. All treated plots had significantly fewer damaged bolls when compared to the controls. A seed cotton yield of 5987 kg/ha was recorded in the plots that were treated with Bolldex®—significantly higher than the yields from plots treated with Eco-Bb®, Delfin®, and Bb endophyte—in 2017. However, the yield in treatments with Eco-Bb®, Delfin®, and Bb endophyte was lower than that from the untreated controls during this season. In 2018, plots treated with Bolldex® had the highest yield, at 6818 kg/ha, which was not different from the other treatments. The highest average seed cotton yield of 6400 kg/ha was recorded in the plots treated with Bolldex®, followed by Karate®. In summary, the efficacy of different biopesticides against H. armigera varied significantly, while the synthetic pesticide (Karate®) and Bolldex® resulted in more consistent control of this pest. The results suggest that biopesticides may, however, have the potential for use in the sustainable control of cotton bollworms as part of integrated pest management programmes, although further work is required to support this hypothesis.
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Affiliation(s)
- Lawrence N. Malinga
- Agricultural Research Council–Industrial Crops, Rustenburg 0300, South Africa
- South African Sugarcane Research Institute, Mount Edgecombe 4300, South Africa
- Correspondence: ; Tel.: +27-84-900-9262
| | - Mark D. Laing
- School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering & Science, University of KwaZulu-Natal, Pietermaritzburg 3209, South Africa;
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Liang Z, Ali Q, Wang Y, Mu G, Kan X, Ren Y, Manghwar H, Gu Q, Wu H, Gao X. Toxicity of Bacillus thuringiensis Strains Derived from the Novel Crystal Protein Cry31Aa with High Nematicidal Activity against Rice Parasitic Nematode Aphelenchoides besseyi. Int J Mol Sci 2022; 23:ijms23158189. [PMID: 35897765 PMCID: PMC9331774 DOI: 10.3390/ijms23158189] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/11/2022] [Accepted: 07/19/2022] [Indexed: 11/16/2022] Open
Abstract
The plant parasitic nematode, Aphelenchoides besseyi, is a serious pest causing severe damage to various crop plants and vegetables. The Bacillus thuringiensis (Bt) strains, GBAC46 and NMTD81, and the biological strain, FZB42, showed higher nematicidal activity against A. besseyi, by up to 88.80, 82.65, and 75.87%, respectively, in a 96-well plate experiment. We screened the whole genomes of the selected strains by protein-nucleic acid alignment. It was found that the Bt strain GBAC46 showed three novel crystal proteins, namely, Cry31Aa, Cry73Aa, and Cry40ORF, which likely provide for the safe control of nematodes. The Cry31Aa protein was composed of 802 amino acids with a molecular weight of 90.257 kDa and contained a conserved delta-endotoxin insecticidal domain. The Cry31Aa exhibited significant nematicidal activity against A. besseyi with a lethal concentration (LC50) value of 131.80 μg/mL. Furthermore, the results of in vitro experiments (i.e., rhodamine and propidium iodide (PI) experiments) revealed that the Cry31Aa protein was taken up by A. besseyi, which caused damage to the nematode's intestinal cell membrane, indicating that the Cry31Aa produced a pore-formation toxin. In pot experiments, the selected strains GBAC46, NMTD81, and FZB42 significantly reduced the lesions on leaves by up to 33.56%, 45.66, and 30.34% and also enhanced physiological growth parameters such as root length (65.10, 50.65, and 55.60%), shoot length (68.10, 55.60, and 59.45%), and plant fresh weight (60.71, 56.45, and 55.65%), respectively. The number of nematodes obtained from the plants treated with the selected strains (i.e., GBAC46, NMTD81, and FZB42) and A. besseyi was significantly reduced, with 0.56, 0.83., 1.11, and 5.04 seedling mL-1 nematodes were achieved, respectively. Moreover, the qRT-PCR analysis showed that the defense-related genes were upregulated, and the activity of hydrogen peroxide (H2O2) increased while malondialdehyde (MDA) decreased in rice leaves compared to the control. Therefore, it was concluded that the Bt strains GBAC46 and NMTD81 can promote rice growth, induce high expression of rice defense-related genes, and activate systemic resistance in rice. More importantly, the application of the novel Cry31Aa protein has high potential for the efficient and safe prevention and green control of plant parasitic nematodes.
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Affiliation(s)
- Zhao Liang
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Qurban Ali
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Yujie Wang
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Guangyuan Mu
- Shenzhen Batian Ecotypic Engineering Co., Ltd., Shenzhen 518057, China; (G.M.); (X.K.)
| | - Xuefei Kan
- Shenzhen Batian Ecotypic Engineering Co., Ltd., Shenzhen 518057, China; (G.M.); (X.K.)
| | - Yajun Ren
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Hakim Manghwar
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang 332000, China;
| | - Qin Gu
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Huijun Wu
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Xuewen Gao
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, China; (Z.L.); (Q.A.); (Y.W.); (Y.R.); (Q.G.); (H.W.)
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: ; Tel.: +86-025-8439-5268
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Hinnekens P, Mahillon J. Conjugation-mediated transfer of pXO16, a large plasmid from Bacillus thuringiensis sv. israelensis, across the Bacillus cereus group and its impact on host phenotype. Plasmid 2022; 122:102639. [PMID: 35842001 DOI: 10.1016/j.plasmid.2022.102639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/27/2022] [Accepted: 07/10/2022] [Indexed: 11/17/2022]
Abstract
pXO16, the 350 kb-conjugative plasmid from Bacillus thuringiensis sv. israelensis promotes its own transfer at high efficiency, triggers the transfer of mobilizable and non-mobilizable plasmids, as well as the transfer of host chromosomal loci. Naturally found in B. thuringiensis sv. israelensis, pXO16 transfers to various strains of Bacillus cereus sensu lato (s.l.) at a wide range of frequencies. Despite this host diversity, a paradox remains between the relatively large host spectrum and the natural occurrence of pXO16, so far restricted to B. thuringiensis sv. israelensis. Proposing first insights exploring this paradox, we investigated the behaviour of pXO16 amongst different members of the B. cereus group. We first looked at the transfer of pXO16 to two new host clusters of B. cereus s.l., Bacillus mycoides and Bacillus anthracis clusters. This examination brought to light the impairment of the characteristic rhizoidal phenotype of B. mycoides in presence of pXO16. We also explored the stability of pXO16 at different temperatures as some B. cereus group members are well-known for their psychro- or thermo-tolerance. This shed light on the thermo-sensitivity of the plasmid. The influence of pXO16 on its host cell growth and on swimming capacity also revealed no or limited impact on its natural host B. thuringiensis sv. israelensis. On the contrary, pXO16 affected more strongly both the growth and swimming capacity of other B. cereus s.l. hosts. This reinforced the running hypothesis of a co-evolution between pXO16 and B. thuringiensis sv. israelensis, enabling the plasmid maintenance without impairing the host strain development.
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Affiliation(s)
- Pauline Hinnekens
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
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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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14
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Yu Z, Fu Y, Zhang W, Zhu L, Yin W, Chou SH, He J. The RNA Chaperone Protein Hfq Regulates the Characteristic Sporulation and Insecticidal Activity of Bacillus thuringiensis. Front Microbiol 2022; 13:884528. [PMID: 35479624 PMCID: PMC9037596 DOI: 10.3389/fmicb.2022.884528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Bacillus thuringiensis (Bt) is one of the most widely used bio-insecticides at present. It can produce many virulence factors and insecticidal crystal proteins during growth and sporulation. Hfq, on the other hand, is a bacterial RNA chaperone that can regulate the function of different kinds of RNAs, thereby affecting various bacterial phenotypes. To further explore the physiological functions of Hfq in Bt, we took BMB171 as the starting strain, knocked out one, two, or three hfq genes in its genome in different combinations, and compared the phenotypic differences between the deletion mutant strains and the starting strain. We did observe significant changes in several phenotypes, including motility, biofilm formation, sporulation, and insecticidal activity against cotton bollworm, among others. Afterward, we found through transcriptome studies that when all hfq genes were deleted, 32.5% of the genes in Bt were differentially transcribed, with particular changes in the sporulation-related and virulence-related genes. The above data demonstrated that Hfq plays a pivotal role in Bt and can regulate its various physiological functions. Our study on the regulatory mechanism of Hfq in Bt, especially the mining of the regulatory network of its sporulation and insecticidal activity, could lay a theoretical foundation for the better utilization of Bt as an effective insecticide.
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Affiliation(s)
- Zhaoqing Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yang Fu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.,National Engineering Research Center of Edible Fungi, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Wei Zhang
- 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
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Ricietto APS, Gonçalves KCB, Appel RJC, Sosa-Gómez DR, Vilas-Bôas GT, Vilas-Boas LA. Complete genome sequence of Bacillus thuringiensis BR145, a strain with insecticidal activity against Lepidoptera pests. Genet Mol Biol 2022; 45:e20210289. [PMID: 35298585 PMCID: PMC8929511 DOI: 10.1590/1678-4685-gmb-2021-0289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/03/2022] [Indexed: 11/22/2022] Open
Abstract
Bacillus thuringiensis BR145 isolated from a soybean field in Southern Brazil showed toxicity against two important insect pests from soybean crop, Helicoverpa armigera, and Chrysodeixis includens, with LC50 0.294 µg.cm-2 and 0.277 µg.cm-2, respectively. We analyzed the genome of this strain through sequences obtained by Next Generation DNA Sequencing and de novo assembly. The analysis of the genome revealed insecticidal genes cry1Aa, cry1Ab, cry1Ac, cry1Ia, cry2Ab, cyt1, and vip3Aa, suggesting the use of this strain in new strategies of biological control.
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Affiliation(s)
| | | | | | - Daniel Ricardo Sosa-Gómez
- Empresa Brasileira de Pesquisa Agropecuária (Embrapa Soja), Centro Nacional de Pesquisa de Soja, Londrina, PR, Brazil
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Gaballa A, Cheng RA, Trmcic A, Kovac J, Kent DJ, Martin NH, Wiedmann M. Development of a database and standardized approach for rpoB sequence-based subtyping and identification of aerobic spore-forming Bacillales. J Microbiol Methods 2021; 191:106350. [PMID: 34710512 DOI: 10.1016/j.mimet.2021.106350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 10/20/2022]
Abstract
Aerobic spore-forming Bacillales are a highly diverse and ubiquitous group that includes organisms that cause foodborne illnesses and food spoilage. Classical microbiological and biochemical identification of members of the order Bacillales represents a challenge due to the diversity of organisms in this group as well as the fact that the phenotypic-based taxonomic assignment of some named species in this group is not consistent with their phylogenomic characteristics. DNA-sequencing-based tools, on the other hand, can be fast and cost-effective, and can provide for a more reliable identification and characterization of Bacillales isolates. In comparison to 16S rDNA, rpoB was shown to better discriminate between Bacillales isolates and to allow for improved taxonomic assignment to the species level. However, the lack of a publicly accessible rpoB database, as well as the lack of standardized protocols for rpoB-based typing and strain identification, is a major challenge. Here, we report (i) the curation of a DNA sequence database for rpoB-based subtype classification of Bacillales isolates; (ii) the development of standardized protocols for generating rpoB sequence data, and a scheme for rpoB-based initial taxonomic identification of Bacillales isolates at the species level; and (iii) the integration of the database in a publicly accessible online platform that allows for the analysis of rpoB sequence data from uncharacterized Bacillales isolates. Specifically, we curated a database of DNA sequences for a 632-nt internal variable region within the rpoB gene from representative Bacillales reference type strains and a large number of isolates that we have previously isolated and characterized through multiple projects. As of May 21, 2021, the rpoB database contained more than 8350 rpoB sequences representing 1902 distinct rpoB allelic types that can be classified into 160 different genera. The database also includes 1129 rpoB sequences for representative Bacillales reference type strains as available on May 21, 2021 in the NCBI database. The rpoB database is integrated into the online Food Microbe Tracker platform (www.foodmicrobetracker.com) and can be queried using the integrated BLAST tool to initially subtype and taxonomically identify aerobic and facultative anaerobic spore-formers. While whole-genome sequencing is increasingly used in bacterial taxonomy, the rpoB sequence-based identification scheme described here provides a valuable tool as it allows for rapid and cost-effective initial isolate characterization, which can help to identify and characterize foodborne pathogens and food spoilage bacteria. In addition, the database and primers described here can also be adopted for metagenomics approaches that include rpoB as a target, improving discriminatory power and identification over what can be achieved using 16S rDNA as a target.
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Affiliation(s)
- Ahmed Gaballa
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA.
| | - Rachel A Cheng
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Aljosa Trmcic
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Jasna Kovac
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA; Department of Food Science, The Pennsylvania State University, University Park, PA 16802, USA
| | - David J Kent
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Nicole H Martin
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
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Zhang Y, Zhang A, Li M, He K, Guo S. Nanoparticle-loaded microcapsules providing effective UV protection for Cry1Ac. J Microencapsul 2021; 38:522-532. [PMID: 34615422 DOI: 10.1080/02652048.2021.1990424] [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: 10/20/2022]
Abstract
AIM To prepare several novel microcapsules using chitosan (Cs) and Alginate (Alg) as coating materials, and nano-ZnO, nano-SiO2, nano-TiO2 as UV protective agents for improving UV resistance of Cry1Ac. METHODS Microcapsules were prepared by the layer-by-layer (LbL) self-assembly technique and electrostatic adsorption. The morphologies were observed by scanning electron microscopy (SEM), and the stability under UV radiation was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and bioassay. RESULTS SEM showed that nano-ZnO and nano-TiO2 could be adsorbed on the negatively charged MC with the outermost layer being Alg, while nano-SiO2 could be adsorbed on the positively charged MC with Cs as the outermost layer. SDS-PAGE and bioassay showed that nano-ZnO and nano-SiO2 could provide effective UV protection after 8 h UV irradiation (p > 0.05), and nano-TiO2 could provide effective UV protection after 4 h UV irradiation (p > 0.05). CONCLUSION The microcapsules loaded with nanoparticles provided excellent UV resistance for Cry1Ac.
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Affiliation(s)
- Yongjing Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Aijing Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Mengyuan Li
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Kanglai He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shuyuan Guo
- School of Life Science, Beijing Institute of Technology, Beijing, China
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Transition Phase Regulator AbrB Positively Regulates the sip1Ab1 Gene Expression in Bacillus thuringiensis. Microbiol Spectr 2021; 9:e0007521. [PMID: 34319140 PMCID: PMC8552724 DOI: 10.1128/spectrum.00075-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Bacillus thuringiensis secreted insecticidal proteins (Sip) are a secretion that is toxic to coleopteran pests. However, the transcriptional mechanism of sip genes is still unknown. The transcriptional regulation of the sip1Ab1 gene and the expression of the Sip1Ab1 protein were investigated in this study. The results demonstrated that the secretion of the Sip1Ab1 protein in HD73 was almost the same as that in the original QZL38 strain during the transition phase. Analysis of the β-galactosidase activities of sip1Ab1-lacZ in both the HD73 and abrB mutant strains indicated that the transcription of sip1Ab1 is dependent on AbrB. Electrophoretic mobility shift assays showed that AbrB could bind with the sip1Ab1 promoter, and two binding sites of AbrB in the region of the promoter of sip1Ab1 were determined by DNase I footprinting assays. All of the above-described results proved that AbrB positively regulates the sip1Ab1 gene. IMPORTANCEBacillus thuringiensis Sip proteins are secreted insecticidal toxins that are toxic to coleopteran pests. In this study, we investigated the transcriptional mechanism of the sip gene and showed strong evidence that Sip1Ab1 is secreted in the transition phase and that AbrB, a transition phase regulator that is usually a repressor, positively and directly regulates sip1Ab1. Reports of AbrB positive regulation are rare, even in Bacillus subtilis. To the best of our knowledge, no toxic gene has been reported to be positively regulated by AbrB in Bacillus species.
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Isolation, molecular characterization and pathogenicity of native Bacillus thuringiensis, from Ethiopia, against the tomato leafminer, Tuta absoluta: Detection of a new high lethal phylogenetic group. Microbiol Res 2021; 250:126802. [PMID: 34174672 DOI: 10.1016/j.micres.2021.126802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 11/23/2022]
Abstract
Tuta absoluta (tomato leafminer) is one of the devastating agricultural pest that attack mainly tomatoes. The continuous use of chemical pesticides is not affordable and poses a collateral damage to human and environmental health. This requires integrated pest management to reduce chemical pesticides. B. thuringiensis is a cosmopolitan, antagonistic soil bacterium used to control agricultural pests. In this study, effective Bt strains were screened from different sample sources based on their lepidopteran specific cry genes and larvicidal efficacy against tomato leafminer, T. absoluta under laboratory conditions. Of the 182 bacterial isolates, 55 (30 %) of isolates harbored parasporal protein crystals. Out of these, 34 (62 %) isolates possess one or more lepidopteran specific cry genes: 20 % of isolates positive for cry2, 18.2 % for cry9, 3.6 % for cry1, 16.4 % for cry2 + cry9, 1.8 % for cry1 + cry9, and 1.8 % for cry1 + cry2 + cry9. However, 21 (38.2 %) isolates did not show any lepidopteran specific cry genes. Isolates positive for cry genes showed 36.7-75 % and 46.7-98.3 % mortality against second and third instar larvae of the T. absoluta at the concentration of 108 colony forming units (CFUs) ml-1. Cry1 and cry1 plus other cry gene positive isolates were relatively more pathogenic against T. absoluta. However, third instar larvae of the T. absoluta was more susceptible than second instar larvae. Two of the isolates, AAUF6 and AAUMF9 were effective and scored LT50 values of 2.3 and 2.7 days and LC50 values of 3.4 × 103 and 4.15 × 103 CFUs ml-1 against the third instar larvae, respectively. The phylogenetic studies showed some congruence of groups with cry gene profiles and lethality level of isolates and very interestingly, we have detected a putative new phylogenetic group of Bt from Ethiopia.
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Belousova ME, Malovichko YV, Shikov AE, Nizhnikov AA, Antonets KS. Dissecting the Environmental Consequences of Bacillus thuringiensis Application for Natural Ecosystems. Toxins (Basel) 2021; 13:toxins13050355. [PMID: 34065665 PMCID: PMC8155924 DOI: 10.3390/toxins13050355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 12/30/2022] Open
Abstract
Bacillus thuringiensis (Bt), a natural pathogen of different invertebrates, primarily insects, is widely used as a biological control agent. While Bt-based preparations are claimed to be safe for non-target organisms due to the immense host specificity of the bacterium, the growing evidence witnesses the distant consequences of their application for natural communities. For instance, upon introduction to soil habitats, Bt strains can affect indigenous microorganisms, such as bacteria and fungi, and further establish complex relationships with local plants, ranging from a mostly beneficial demeanor, to pathogenesis-like plant colonization. By exerting a direct effect on target insects, Bt can indirectly affect other organisms in the food chain. Furthermore, they can also exert an off-target activity on various soil and terrestrial invertebrates, and the frequent acquisition of virulence factors unrelated to major insecticidal toxins can extend the Bt host range to vertebrates, including humans. Even in the absence of direct detrimental effects, the exposure to Bt treatment may affect non-target organisms by reducing prey base and its nutritional value, resulting in delayed alleviation of their viability. The immense phenotypic plasticity of Bt strains, coupled with the complexity of ecological relationships they can engage in, indicates that further assessment of future Bt-based pesticides' safety should consider multiple levels of ecosystem organization and extend to a wide variety of their inhabitants.
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Affiliation(s)
- Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
| | - Yury V. Malovichko
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 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; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Correspondence:
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Cerar Kišek T, Pogačnik N, Godič Torkar K. Genetic diversity and the presence of circular plasmids in Bacillus cereus isolates of clinical and environmental origin. Arch Microbiol 2021; 203:3209-3217. [PMID: 33830284 DOI: 10.1007/s00203-021-02302-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
The diversity of 61 Bacillus cereus strains isolated from different clinical specimens, food including raw milk and milk products, and water was evaluated. PFGE analysis could discriminate 61 distinct pulsotypes with similarity levels from 25 to 82%, which were divided into 13 clonal complexes. The similarity between clonal complexes was at least 40%. Clinical strains were divided into 10 clonal complexes, while the strains, isolated from milk, food and water were included in 9, 6 and 6 clonal complexes, respectively. Three clonal complexes were dominated by clinical isolates, while they were absent in two complexes. Bacterial isolates from food, being a probable source of alimentary toxoinfection, showed low similarity to isolates from stool specimens. The isolates from both sources were classified together in only 4 out of 13 clonal complexes. The large circular and linear plasmids with the sizes between 50 and 200 kb were detected in 24 (39.3%) and 14 (23%) B. cereus strains, respectively. Thirteen (21.3%) strains contained only one plasmid, two plasmids were found in 6 (9.8%) of strains, and three or more plasmids were obtained in 5 (8.2%) of tested strains. The plasmids were confirmed in 30.8% and 40% of isolates from clinical specimens and food and milk samples, respectively. No clear correlation between the PFGE profiles, the source as well as plasmid content among all tested strains was observed.
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Affiliation(s)
- Tjaša Cerar Kišek
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Nežka Pogačnik
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000, Ljubljana, Slovenia
| | - Karmen Godič Torkar
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000, Ljubljana, Slovenia.
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Risk of Bacillus cereus in Relation to Rice and Derivatives. Foods 2021; 10:foods10020302. [PMID: 33540849 PMCID: PMC7913059 DOI: 10.3390/foods10020302] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/26/2021] [Indexed: 11/18/2022] Open
Abstract
Rice is a very popular food throughout the world and the basis of the diet of the citizens of many countries. It is used as a raw material for the preparation of many complex dishes in which different ingredients are involved. Rice, as a consequence of their cultivation, harvesting, and handling, is often contaminated with spores of Bacillus cereus, a ubiquitous microorganism found mainly in the soil. B. cereus can multiply under temperature conditions as low as 4 °C in foods that contain rice and have been cooked or subjected to treatments that do not produce commercial sterility. B. cereus produces diarrhoeal or emetic foodborne toxin when the consumer eats food in which a sufficient number of cells have grown. These circumstances mean that every year many outbreaks of intoxication or intestinal problems related to this microorganism are reported. This work is a review from the perspective of risk assessment of the risk posed by B. cereus to the health of consumers and of some control measures that can be used to mitigate such a risk.
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Bacillus thuringiensis Cells Selectively Captured by Phages and Identified by Surface Enhanced Raman Spectroscopy Technique. MICROMACHINES 2021; 12:mi12020100. [PMID: 33498471 PMCID: PMC7909556 DOI: 10.3390/mi12020100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 12/11/2022]
Abstract
In this work, the results on the detection and identification of Bacillus thuringiensis (Bt) cells by using surface-enhanced Raman spectroscopy (SERS) are presented. Bt has been chosen as a harmless surrogate of the pathogen Bacillus anthracis (Ba) responsible for the deadly Anthrax disease, because of their genetic similarities. Drops of 200 μL of Bt suspensions, with concentrations 102 CFU/mL, 104 CFU/mL, 106 CFU/mL, were deposited on a SERS chip and sampled after water evaporation. To minimize the contribution to the SERS data given by naturally occurring interferents present in a real scenario, the SERS chip was functionalized with specific phage receptors BtCS33, that bind Bt (or Ba) cells to the SERS surface and allow to rinse the chip removing unwanted contaminants. Different chemometric approaches were applied to the SERS data to classify spectra from Bt-contaminated and uncontaminated areas of the chip: Principal Component Regression (PCR), Partial Least Squares Regression (PLSR) and Data Driven Soft Independent Modeling of Class Analogy (DD-SIMCA). The first two was tested and trained by using data from both contaminated and un-contaminated chips, the last was trained by using data from un-contaminated chips only and tested with all the available data. All of them were able to correctly classify the SERS spectra with great accuracy, the last being suitable for an automated recognition procedure.
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Traceability of potential enterotoxigenic Bacillus cereus in bee-pollen samples from Argentina throughout the production process. Int J Food Microbiol 2020; 334:108816. [PMID: 32835996 DOI: 10.1016/j.ijfoodmicro.2020.108816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/23/2020] [Accepted: 08/02/2020] [Indexed: 11/21/2022]
Abstract
Bee-pollen is a functional food sold for human and animal consumption but also is a favorable microhabitat for many spore-forming bacteria. Among them, Bacillus cereus can produce several toxins and other virulence factors, causing an emetic or diarrheal syndrome after ingestion. The study involved 36 bee-pollen samples obtained from different sampling points throughout the production process (collecting, freezing, drying, and cleaning) in Argentina. Fifty isolates of B. cereus yielded 24 different fingerprint patterns with BOX and ERIC primers. Only three fingerprint patterns were maintained throughout the production process. In contrast, others were lost or incorporated during the different steps, suggesting that cross-contamination occurred as shown by differences in fingerprint patterns after freezing, drying, and cleaning steps compared to the initial collection step. Genes encoding for cereulide (ces), cytotoxin K (cytK), sphingomyelinase (sph), the components of hemolysin BL (hblA, hblB, hblC, hblD) and non-hemolytic complex (nheAB) were studied. All the isolates displayed one or more enterotoxin genes. The most frequent virulence genes detected belong to the HBL complex, being the most abundant hblA (98%), followed by hblD (64%), hblB (54%), and hblC (32%), respectively. Ten strains (20%), present at all sampling points, carried all the subunits of the HBL complex. The non-hemolytic enterotoxic complex (nheAB) was found in 48 strains (96%), while seven strains (14%) present at all sampling points showed the amplification product for sphingomyelinase (sph). One cereulide-producer was isolated at the cleaning step; this strain contained all the components for the hemolytic enterotoxin complex HBL, the NHE complex, and cytotoxin K related to the foodborne diarrhoeal syndrome. In total, 11 different virulence patterns were observed, and also a correlation between rep-fingerprint and virulence patterns. The results suggest that bee-pollen can be contaminated at any point in the production process with potential enterotoxic B. cereus strains, emphasizing the importance of hygienic processing.
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Nawrot-Esposito MP, Babin A, Pasco M, Poirié M, Gatti JL, Gallet A. Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae. INSECTS 2020; 11:E697. [PMID: 33066180 PMCID: PMC7601982 DOI: 10.3390/insects11100697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes.
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Affiliation(s)
| | | | | | | | | | - Armel Gallet
- Université Côte d’Azur, CNRS, INRAE, ISA, UMR CNRS 7254/INRAE 1355/UCA, 400 route des Chappes, BP 167, 06903 Sophia Antipolis CEDEX, France; (M.-P.N.-E.); (A.B.); (M.P.); (M.P.); (J.-L.G.)
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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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Aminu OR, Lembo T, Zadoks RN, Biek R, Lewis S, Kiwelu I, Mmbaga BT, Mshanga D, Shirima G, Denwood M, Forde TL. Practical and effective diagnosis of animal anthrax in endemic low-resource settings. PLoS Negl Trop Dis 2020; 14:e0008655. [PMID: 32925904 PMCID: PMC7513992 DOI: 10.1371/journal.pntd.0008655] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 09/24/2020] [Accepted: 07/28/2020] [Indexed: 11/19/2022] Open
Abstract
Anthrax threatens human and animal health, and people's livelihoods in many rural communities in Africa and Asia. In these areas, anthrax surveillance is challenged by a lack of tools for on-site detection. Furthermore, cultural practices and infrastructure may affect sample availability and quality. Practical yet accurate diagnostic solutions are greatly needed to quantify anthrax impacts. We validated microscopic and molecular methods for the detection of Bacillus anthracis in field-collected blood smears and identified alternative samples suitable for anthrax confirmation in the absence of blood smears. We investigated livestock mortalities suspected to be caused by anthrax in northern Tanzania. Field-prepared blood smears (n = 152) were tested by microscopy using four staining techniques as well as polymerase chain reaction (PCR) followed by Bayesian latent class analysis. Median sensitivity (91%, CI 95% [84-96%]) and specificity (99%, CI 95% [96-100%]) of microscopy using azure B were comparable to those of the recommended standard, polychrome methylene blue, PMB (92%, CI 95% [84-97%] and 98%, CI 95% [95-100%], respectively), but azure B is more available and convenient. Other commonly-used stains performed poorly. Blood smears could be obtained for <50% of suspected anthrax cases due to local customs and conditions. However, PCR on DNA extracts from skin, which was almost always available, had high sensitivity and specificity (95%, CI 95% [90-98%] and 95%, CI 95% [87-99%], respectively), even after extended storage at ambient temperature. Azure B microscopy represents an accurate diagnostic test for animal anthrax that can be performed with basic laboratory infrastructure and in the field. When blood smears are unavailable, PCR using skin tissues provides a valuable alternative for confirmation. Our findings lead to a practical diagnostic approach for anthrax in low-resource settings that can support surveillance and control efforts for anthrax-endemic countries globally.
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Affiliation(s)
- Olubunmi R. Aminu
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Tiziana Lembo
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Ruth N. Zadoks
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Suzanna Lewis
- Public Health England, Porton Down, Salisbury, United Kingdom
| | - Ireen Kiwelu
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | | | - Gabriel Shirima
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Matt Denwood
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Taya L. Forde
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNA Cys-PCR. Microorganisms 2020; 8:microorganisms8040524. [PMID: 32268545 PMCID: PMC7232370 DOI: 10.3390/microorganisms8040524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/25/2020] [Accepted: 04/03/2020] [Indexed: 01/06/2023] Open
Abstract
Endospore-forming bacteria related to the Bacillus cereus group produce toxins that cause illnesses in organisms from invertebrates to mammals, including foodborne illnesses in humans. As commercial bee pollen can be contaminated with these bacteria, a comprehensive microbiological risk assessment of commercial bee pollen must be incorporated into the relevant regulatory requirements, including those that apply in Mexico. To facilitate detection of members of this group of bacteria, we have developed a PCR strategy that is based on the amplification of the single-copy tRNACys gene and specific genes associated with tRNACys to detect Bacillus cereus sensu lato (B. cereus s.l.). This tRNACys-PCR-based approach was used to examine commercial bee pollen for endospore-forming bacteria. Our analysis revealed that 3% of the endospore-forming colonies isolated from a commercial source of bee pollen were related to B. cereus s.l., and this result was corroborated by phylogenetic analysis, bacterial identification via MALDI-TOF MS, and detection of enterotoxin genes encoding the HBL and NHE complexes. The results show that the isolated colonies are closely related phylogenetically to B. cereus, B. thuringiensis, and B. bombysepticus. Our results indicate that the tRNACys-PCR, combined with other molecular tools, will be a useful approach for identifying B. cereus s.l. and will assist in controlling the spread of potential pathogens.
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Adame-Gómez R, Muñoz-Barrios S, Castro-Alarcón N, Leyva-Vázquez MA, Toribio-Jiménez J, Ramírez-Peralta A. Prevalence of the Strains of Bacillus cereus Group in Artisanal Mexican Cheese. Foodborne Pathog Dis 2020; 17:8-14. [DOI: 10.1089/fpd.2019.2673] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Roberto Adame-Gómez
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero, México
| | - Salvador Muñoz-Barrios
- Laboratorio de Investigación en Inmunotoxigenómica, Universidad Autónoma de Guerrero, Guerrero, México
| | - Natividad Castro-Alarcón
- Laboratorio de Investigación en Microbiología, Universidad Autónoma de Guerrero, Guerrero, México
| | | | - Jeiry Toribio-Jiménez
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Universidad Autónoma de Guerrero, Guerrero, México
| | - Arturo Ramírez-Peralta
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero, México
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Teramura H, Otsubo M, Saito H, Ishii A, Suzuki M, Ogihara H. Comparative Evaluation of Selective Media for the Detection of Bacillus cereus. Biocontrol Sci 2019; 24:221-227. [PMID: 31875614 DOI: 10.4265/bio.24.221] [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: 11/01/2022]
Abstract
The commercially available 3 types of selective media in Japan were compared for the detection of Bacillus cereus. When assessed inclusivity using 25 B. cereus strains, MYP agar, NGKG agar, and chromogenic X-BC agar demonstrated excellent inclusivity. For exclusivity study using 50 non-B. cereus strains, MYP, NGKG, and X-BC allowed to grow 11, 7, and 3 strains, respectively. Of the grown bacteria on each strains tested, only 2 strains of B. thuringiensis formed typical B. cereus colonies on all selective media tested. The NGKG and X-BC were compared with MYP as a reference using artificially contaminated food (fried rice, plain rice, fried noodle, and potato salad ), since MYP is recommended in ISO 7932: 2004. The both correlation coefficients between NGKG and MYP, and X-BC and MYP were 0.999. Therefore, we demonstrated that NGKG and X-BC can be adapted to ISO 7932: 2004 method for selected food as well as MYP.
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Affiliation(s)
- Hajime Teramura
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University.,Yokohama Research Center, JNC Corporation
| | - Megumi Otsubo
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University
| | - Hitomi Saito
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University
| | - Aoi Ishii
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University
| | - Misa Suzuki
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University
| | - Hirokazu Ogihara
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University
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Bacillus subtilis, an ideal probiotic bacterium to shrimp and fish aquaculture that increase feed digestibility, prevent microbial diseases, and avoid water pollution. Arch Microbiol 2019; 202:427-435. [PMID: 31773195 DOI: 10.1007/s00203-019-01757-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 05/05/2019] [Accepted: 10/24/2019] [Indexed: 12/17/2022]
Abstract
Beneficial microorganisms maintain the ecosystems, plants, animals and humans working in healthy conditions. In nature, around 95% of all microorganisms produce beneficial effects by increasing nutrients digestion and assimilation, preventing pathogens development and by improving environmental parameters. However, increase in human population and indiscriminate uses of antibiotics have been exerting a great pressure on agriculture, livestock, aquaculture, and also to the environment. This pressure has induced the decomposition of environmental parameters and the development of pathogenic strains resistant to most antibiotics. Therefore, all antibiotics have been restricted by corresponding authorities; hence, new and healthy alternatives to prevent or eliminate these pathogens need to be identified. Thus, probiotic bacteria utilization in aquaculture systems has emerged as a solution to prevent pathogens development, to enhance nutrients assimilation and to improve environmental parameters. In this sense, B. subtilis is an ideal multifunctional probiotic bacterium, with the capacity to solve these problems and also to increase aquaculture profitability.
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Complete genome sequence of novel isolate SYJ15 of Bacillus cereus group, a highly lethal pathogen isolated from Chinese soft shell turtle (Pelodiscus Sinensis). Arch Microbiol 2019; 202:85-92. [DOI: 10.1007/s00203-019-01723-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 08/16/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022]
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López AC, Alippi AM. Feasibility of using RFLP of PCR-amplified 16S rRNA gene(s) for rapid differentiation of isolates of aerobic spore-forming bacteria from honey. J Microbiol Methods 2019; 165:105690. [PMID: 31425714 DOI: 10.1016/j.mimet.2019.105690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 11/24/2022]
Abstract
This study aimed to assess the feasibility of using RFLP of PCR-amplified 16S rRNA gene (s) by using universal primers 27f/1492r and a combination of three restriction enzymes, AluI, CfoI, and TaqI, for a low-cost, rapid screen for a primarily differentiation of isolates of the complex of aerobic spore-forming bacteria commonly found in honey samples. The described method produced unique and distinguishable patterns to differentiate among 80 isolates belonging to 26 different species of Bacillus, Brevibacillus, Lysinibacillus, Rummeliibacillus, and Paenibacillus reported in honey and other apiarian sources.
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Affiliation(s)
- Ana C López
- Unidad de Bacteriología, Centro de Investigaciones de Fitopatología, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, cc 31, calle 60 y 119, 1900 La Plata, Argentina
| | - Adriana M Alippi
- Unidad de Bacteriología, Centro de Investigaciones de Fitopatología, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, cc 31, calle 60 y 119, 1900 La Plata, Argentina.
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Sensitivity of Heterotrophic Bacteria in the Low-Salinity Water Areas and Estuary in Siak District toward Pathogenic Bacteria in Fish. Int J Microbiol 2019; 2019:7456410. [PMID: 31281364 PMCID: PMC6590592 DOI: 10.1155/2019/7456410] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/21/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
The high rate of bacterial diseases in fishes and shrimps has lead scientists seek for natural antibiotic products that would act as a solution. An example of this product is the secondary metabolic products from heterotrophic bacteria. These bacteria could easily be found in many water regions and estuaries, including the Siak District, Riau, Indonesia. Therefore, this study aims at determining the ability of bacterial isolates in inhibiting the growth of pathogens (Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas sp.). The research was conducted from June to September 2018. It actuates the type of heterotrophic bacteria in the sampling area using the PCR technique. The phylogenetic structure of bacterial isolates obtained during this study was assessed by nucleotide sequencing of the 16S rRNA gene. The antagonism test showed that bacteria had the ability to inhibit the growth of pathogens (Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas sp.). The results showed that 25 pure bacterial isolates were obtained, in which 10 of those were carried out by DNA sequencing; hence, it could be used as antimicrobes. Based on the analysis of 16S rDNA, 10 isolates were identified: 6 were Bacillus cereus and 2 were Pseudomonas aeruginosa with homology levels ranging from 97 to 99%, while the remaining two were suspected as the new species of isolates. From the result, it could be concluded that heterotrophic bacteria are found to be better used as antipathogens against Vibrio alginolitycus than hydrophila and Pseudomonas sp.
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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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Yuan Y, Peng Q, Zhang S, Liu T, Yang S, Yu Q, Wu Y, Gao M. Phage Reduce Stability for Regaining Infectivity during Antagonistic Coevolution with Host Bacterium. Viruses 2019; 11:v11020118. [PMID: 30699954 PMCID: PMC6410104 DOI: 10.3390/v11020118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/15/2019] [Accepted: 01/28/2019] [Indexed: 12/19/2022] Open
Abstract
The coevolution between phage and host bacterium is an important force that drives the evolution of the microbial community, yet the coevolution mechanisms have still not been well analyzed. Here, by analyzing the interaction between a Bacillus phage vB_BthS_BMBphi and its host bacterium, the coevolution mechanisms of the first-generation phage-resistant bacterial mutants and regained-infectivity phage mutants were studied. The phage-resistant bacterial mutants showed several conserved mutations as a potential reason for acquiring phage resistance, including the mutation in flagellum synthesis protein FlhA and cell wall polysaccharide synthesis protein DltC. All the phage-resistant bacterial mutants showed a deleted first transmembrane domain of the flagellum synthesis protein FlhA. Meanwhile, the regain-infectivity phage mutants all contained mutations in three baseplate-associated phage tail proteins by one nucleotide, respectively. A polymorphism analysis of the three mutant nucleotides in the wild-type phage revealed that the mutations existed before the interaction of the phage and the bacterium, while the wild-type phage could not infect the phage-resistant bacterial mutants, which might be because the synchronized mutations of the three nucleotides were essential for regaining infectivity. This study for the first time revealed that the synergism mutation of three phage baseplate-associated proteins were essential for the phages’ regained infectivity. Although the phage mutants regained infectivity, their storage stability was decreased and the infectivity against the phage-resistant bacterial mutants was reduced, suggesting the phage realized the continuation of the species by way of “dying to survive”.
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Affiliation(s)
- Yihui Yuan
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Qin Peng
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
| | - Shaowen Zhang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Tingting Liu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Shuo Yang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Qiuhan Yu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
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Search for Cry proteins expressed by Bacillus spp. genomes, using hidden Markov model profiles. 3 Biotech 2019; 9:13. [PMID: 30622851 DOI: 10.1007/s13205-018-1533-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/14/2018] [Indexed: 12/12/2022] Open
Abstract
This report focuses on a systematic search for Cry proteins in Bacillus spp. other than B. thuringiensis by analyzing reported Bacillus spp. genomes, using conserved sequences from the C-terminal half of reported Cry proteins in hidden Markov model profiles. A high-throughput model based on the use of HMMER and CD-HIT tools was designed, which identified Cry proteins. This model was used on 857 reported Bacillus spp. genomes, where 174 Cry protein sequences were identified, mostly, as expected, in B. thuringiensis genomes but, interestingly, 42 were identified on other species. Despite including 89 species of Bacillus in the HMMER analysis, Cry protein sequences were found only in genomes from species within the B. cereus group. According to the species registered at the NCBI database containing each genome, this group was formed by 18 non-B. thuringiensis strains. However, when sequences in those genomes were analyzed by multilocus sequence typing, the number of non-B. thuringiensis strains increased to 39, indicating that as many as 119 Cry protein sequences were found in four non-B. thuringiensis species. Therefore, dispersion of Cry proteins is much wider and frequent than previously thought, questioning its role in nature.
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Yuan Y, Peng Q, Yang S, Zhang S, Fu Y, Wu Y, Gao M. Isolation of A Novel Bacillus thuringiensis Phage Representing A New Phage Lineage and Characterization of Its Endolysin. Viruses 2018; 10:v10110611. [PMID: 30404215 PMCID: PMC6266608 DOI: 10.3390/v10110611] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/29/2018] [Accepted: 11/06/2018] [Indexed: 01/03/2023] Open
Abstract
Phages, the parasites of bacteria, are considered as a new kind of antimicrobial agent due to their ability to lyse pathogenic bacteria. Due to the increase of available phage isolates, the newly isolated phage showed increasing genomic similarities with previously isolated phages. In this study, the novel phage vB_BthS_BMBphi, infecting the Bacillus thuringiensis strain BMB171, is isolated and characterized together with its endolysin. This phage is the first tadpole-like phage infecting the Bacillus strains. Genomic analysis shows that the phage genome is dissimilar to all those of previously characterized phages, only exhibiting low similarities with partial regions of the B. thuringiensis prophages. Phylogenetic analysis revealed that the phage was distant from the other Bacillus phages in terms of evolution. The novel genome sequence, the distant evolutionary relationship, and the special virion morphology together suggest that the phage vB_BthS_BMBphi could be classified as a new phage lineage. The genome of the phage is found to contain a restriction modification system, which might endow the phage with immunity to the restriction modification system of the host bacterium. The function of the endolysin PlyBMB encoded by the phage vB_BthS_BMBphi was analyzed, and the endolysin could lyse all the tested Bacillus cereus group strains, suggesting that the endolysin might be used in controlling pathogenic B. cereus group strains. The findings of this study enrich the understanding of phage diversity and provide a resource for controlling the B. cereus group pathogenic bacteria.
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Affiliation(s)
- Yihui Yuan
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Qin Peng
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
| | - Shuo Yang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Shaowen Zhang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
| | - Yajuan Fu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
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Daas MS, Rosana ARR, Acedo JZ, Douzane M, Nateche F, Kebbouche-Gana S, Vederas JC. Insights into the draft genome sequence of bioactives-producing Bacillus thuringiensis DNG9 isolated from Algerian soil-oil slough. Stand Genomic Sci 2018; 13:25. [PMID: 30344888 PMCID: PMC6186030 DOI: 10.1186/s40793-018-0331-1] [Citation(s) in RCA: 10] [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: 02/26/2018] [Accepted: 09/28/2018] [Indexed: 12/16/2022] Open
Abstract
Bacillus thuringiensis is widely used as a bioinsecticide due to its ability to form parasporal crystals containing proteinaceous toxins. It is a member of the Bacillus cereus sensu lato, a group with low genetic diversity but produces several promising antimicrobial compounds. B. thuringiensis DNG9, isolated from an oil-contaminated slough in Algeria, has strong antibacterial, antifungal and biosurfactant properties. Here, we report the 6.06 Mbp draft genome sequence of B. thuringiensis DNG9. The genome encodes several gene inventories for the biosynthesis of bioactive compounds such as zwittermycin A, petrobactin, insecticidal toxins, polyhydroxyalkanoates and multiple bacteriocins. We expect the genome information of strain DNG9 will provide another model system to study pathogenicity against insect pests, plant diseases, and antimicrobial compound mining and comparative phylogenesis among the Bacillus cereus sensu lato group.
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Affiliation(s)
- Mohamed Seghir Daas
- Valcore Laboratory, Department of Biology, University M’Hamed Bougara of Boumerdes, 35000 Boumerdes, Algeria
- Food Technology Research Division, Institut National de la Recherche Agronomique d’Algérie, 16200, El Harrach, Algiers, Algeria
| | | | - Jeella Z. Acedo
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada
| | - Malika Douzane
- Food Technology Research Division, Institut National de la Recherche Agronomique d’Algérie, 16200, El Harrach, Algiers, Algeria
| | - Farida Nateche
- Microbiology Group, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Science and Technology–Houari Boumediene, 16111, Bab Ezzouar, Algiers, Algeria
| | - Salima Kebbouche-Gana
- Valcore Laboratory, Department of Biology, University M’Hamed Bougara of Boumerdes, 35000 Boumerdes, Algeria
| | - John C. Vederas
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada
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Walia K, Kapoor A, Farber J. Qualitative risk assessment of cricket powder to be used to treat undernutrition in infants and children in Cambodia. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.04.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Peng Q, Yuan Y. Characterization of a novel phage infecting the pathogenic multidrug-resistant Bacillus cereus and functional analysis of its endolysin. Appl Microbiol Biotechnol 2018; 102:7901-7912. [PMID: 30008020 DOI: 10.1007/s00253-018-9219-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/24/2018] [Accepted: 07/03/2018] [Indexed: 01/01/2023]
Abstract
Bacillus cereus is widely distributed food-borne pathogenic bacterium. Due to the harmness to human hearth and the generation of multidrug-resistant B. cereus, it is urgent to develop novel antimicrobial agents. Phage and phage endolysin were taken as novel antimicrobial substance for their specific lytic activity against pathogenic bacteria. In this study, a Myoviridae family phage, designated as vB_BceM-HSE3, infecting the pathogenic multidrug-resistant B. cereus strain was isolated and characterized along with its endolysin. Phage vB_BceM-HSE3 can specially infect the B. cereus group strains, including B. cereus, B. anthracis, and B. thuringiensis, and exhibits high temperature and pH tolerance, which endow it with high potential for been used in controlling pathogenic B. cereus group strains. Genomic analysis reveals that vB_BceM-HSE3 is a novel phage and only shows extremely low genome similarity with available phage genome. Functional analysis of endolysin PlyHSE3 encoding by vB_BceM-HSE3 shows that PlyHSE3 exhibits broader lytic spectrum than the phage and can lyse all the tested B. cereus group strains as well as the tested pathogenic strain of P. aeruginosa. PlyHSE3 also shows broad temperature and pH tolerance, and can efficiently lyse B. cereus strain at temperature at 4 °C and higher than 45 °C, which indicating that PlyHSE3 might can be used in controlling food-borne B. cereus during both the cold storage of food and the stage after the heat treatment of food. The findings of this study enrich our understanding of phage diversity as well as providing resources for developing phage therapy.
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Affiliation(s)
- Qin Peng
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, People's Republic of China
| | - Yihui Yuan
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, China.
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Genes under positive selection in the core genome of pathogenic Bacillus cereus group members. INFECTION GENETICS AND EVOLUTION 2018; 65:55-64. [PMID: 30006047 DOI: 10.1016/j.meegid.2018.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 11/24/2022]
Abstract
In this comparative genomics study our aim was to unravel genes under positive selection in the core genome of the Bacillus cereus group. Indeed, the members of this group share close genetic relationships but display a rather large phenotypic and ecological diversity, providing a unique opportunity for studying how genomic changes reflect ecological adaptation during the divergence of a bacterial group. For this purpose, we screened ten completely sequenced genomes of four pathogenic Bacillus species, finding that 254 out of 3093 genes have codon sites with dN/dS (ω) values above one. These results remained unchanged after having disentangled the confounding effects of recombination and selection signature in a Bayesian framework. The presumably adaptive nucleotide polymorphisms are distributed over a wide range of biological functions, such as antibiotic resistance, DNA repair, nutrient uptake, metabolism, cell wall assembly and spore structure. Our results indicate that adaptation to animal hosts, whether as pathogens, saprophytes or symbionts, is the major driving force in the evolution of the Bacillus cereus group. Future work should seek to understand the evolutionary dynamics of both core and accessory genes in an integrative framework to ultimately unravel the key networks involved in host adaptation.
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Novel Cell Wall Hydrolase CwlC from Bacillus thuringiensis Is Essential for Mother Cell Lysis. Appl Environ Microbiol 2018; 84:AEM.02640-17. [PMID: 29374039 DOI: 10.1128/aem.02640-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/10/2018] [Indexed: 11/20/2022] Open
Abstract
In this study, a sporulation-specific gene (tentatively named cwlC) involved in mother cell lysis in Bacillus thuringiensis was characterized. The encoded CwlC protein consists of an N-terminal N-acetylmuramoyl-l-alanine amidase (MurNAc-LAA) domain and a C-terminal amidase02 domain. The recombinant histidine-tagged CwlC proteins purified from Escherichia coli were able to directly bind to and digest the B. thuringiensis cell wall. The CwlC point mutations at the two conserved glutamic acid residues (Glu-24 and Glu-140) shown to be critical for the catalytic activity in homologous amidases resulted in a complete loss of cell wall lytic activity, suggesting that CwlC is an N-acetylmuramoyl-l-alanine amidase. Results of transcriptional analyses indicated that cwlC is transcribed as a monocistronic unit and that its expression is dependent on sporulation sigma factor K (σK). Deletion of cwlC completely blocked mother cell lysis during sporulation without impacting the sporulation frequency, Cry1Ac protein production, and insecticidal activity. Taken together, our data suggest that CwlC is an essential cell wall hydrolase for B. thuringiensis mother cell lysis during sporulation. Engineered B. thuringiensis strains targeting cwlC, which allows the crystal inclusion to remain encapsulated in the mother cell at the end of sporulation, may have the potential to become more effective biological control agents in agricultural applications since the crystal inclusion remains encapsulated in the mother cell at the end of sporulation.IMPORTANCE Mother cell lysis has been well studied in Bacillus subtilis, which involves three distinct yet functionally complementary cell wall hydrolases. In this study, a novel cell wall hydrolase, CwlC, was investigated and found to be essential for mother cell lysis in Bacillus thuringiensis CwlC of B. thuringiensis only shows 9 and 21% sequence identity with known B. subtilis mother cell hydrolases CwlB and CwlC, respectively, suggesting that mechanisms of mother cell lysis may differ between B. subtilis and B. thuringiensis The cwlC gene deletion completely blocked the release of spores and crystals from the mother cell without affecting insecticidal activity. This may provide a new effective strategy for crystal encapsulation against UV light inactivation.
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Schneider S, Tajrin T, Lundström JO, Hendriksen NB, Melin P, Sundh I. Do Multi-year Applications of Bacillus thuringiensis subsp. israelensis for Control of Mosquito Larvae Affect the Abundance of B. cereus Group Populations in Riparian Wetland Soils? MICROBIAL ECOLOGY 2017; 74:901-909. [PMID: 28600590 DOI: 10.1007/s00248-017-1004-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Bacillus thuringiensis subsp. israelensis (Bti) is a soil-borne bacterium affiliated to the Bacillus cereus group (Bcg) and has been used in biocontrol products against nematoceran larvae for several decades. However, knowledge is limited on whether long-term Bti application can affect the structure of indigenous communities of Bcg and the overall abundance of Bti. Using species- and group-specific quantitative PCR assays, we measured the Bcg- and Bti-abundances in riparian wetlands in the River Dalälven floodplains of central Sweden. On five occasions during one vegetative season, soil samples were collected in alder swamps and wet meadows which had been treated with Bti for mosquito larvae control during the preceding 11 years, as well as in untreated control sites and well-drained forests in the same area. The average abundance of Bcg in alder swamps was around three times higher than in wet meadows. Across all sites and habitats, the Bti treatments had no effect on the Bcg-abundance, whereas the Bti-abundance was significantly higher in the treated than in the control sites. However, for individual sampling sites, abundances of Bti and Bcg were not correlated with the number of Bti applications, indicating that added Bti possibly influenced the total population of Bti in the short term but had only a limited effect in the longer term. The findings of this study increase the understanding of the ecology of Bti applications for mosquito control, which can facilitate environmental risk assessment in connection with approval of microbiological control agents.
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Affiliation(s)
- Salome Schneider
- Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
- Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
| | - Tania Tajrin
- Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Jan O Lundström
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden
- Swedish Biological Mosquito Control Project, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden
| | - Niels B Hendriksen
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | | | - Ingvar Sundh
- Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- Department of Molecular Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
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The CodY-dependent clhAB2 operon is involved in cell shape, chaining and autolysis in Bacillus cereus ATCC 14579. PLoS One 2017; 12:e0184975. [PMID: 28991912 PMCID: PMC5633148 DOI: 10.1371/journal.pone.0184975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 09/05/2017] [Indexed: 11/19/2022] Open
Abstract
The Gram-positive pathogen Bacillus cereus is able to grow in chains of rod-shaped cells, but the regulation of chaining remains largely unknown. Here, we observe that glucose-grown cells of B. cereus ATCC 14579 form longer chains than those grown in the absence of glucose during the late exponential and transition growth phases, and identify that the clhAB2 operon is required for this chain lengthening phenotype. The clhAB2 operon is specific to the B. cereus group (i.e., B. thuringiensis, B. anthracis and B. cereus) and encodes two membrane proteins of unknown function, which are homologous to the Staphylococcus aureus CidA and CidB proteins involved in cell death control within glucose-grown cells. A deletion mutant (ΔclhAB2) was constructed and our quantitative image analyses show that ΔclhAB2 cells formed abnormal short chains regardless of the presence of glucose. We also found that glucose-grown cells of ΔclhAB2 were significantly wider than wild-type cells (1.47 μm ±CI95% 0.04 vs 1.19 μm ±CI95% 0.03, respectively), suggesting an alteration of the bacterial cell wall. Remarkably, ΔclhAB2 cells showed accelerated autolysis under autolysis-inducing conditions, compared to wild-type cells. Overall, our data suggest that the B. cereus clhAB2 operon modulates peptidoglycan hydrolase activity, which is required for proper cell shape and chain length during cell growth, and down-regulates autolysin activity. Lastly, we studied the transcription of clhAB2 using a lacZ transcriptional reporter in wild-type, ccpA and codY deletion-mutant strains. We found that the global transcriptional regulatory protein CodY is required for the basal level of clhAB2 expression under all conditions tested, including the transition growth phase while CcpA, the major global carbon regulator, is needed for the high-level expression of clhAB2 in glucose-grown cells.
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Hassim A, Dekker EH, Byaruhanga C, Reardon T, Van Heerden H. A retrospective study of anthrax on the Ghaap Plateau, Northern Cape province of South Africa, with special reference to the 2007-2008 outbreaks. Onderstepoort J Vet Res 2017; 84:e1-e15. [PMID: 29041790 PMCID: PMC8616768 DOI: 10.4102/ojvr.v84i1.1414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 05/31/2017] [Accepted: 07/04/2017] [Indexed: 11/20/2022] Open
Abstract
Anthrax is a zoonotic disease caused by the gram-positive, endospore-forming and soil-borne bacterium Bacillus anthracis. When in spore form, the organism can survive in dormancy in the environment for decades. It is a controlled disease of livestock and wild ungulates in South Africa. In South Africa, the two enzootic regions are the Kruger National Park and the Ghaap Plateau in the Northern Cape province. Farms on the Plateau span thousands of hectares comprising of wildlife - livestock mixed use farming. In 2007-2008, anthrax outbreaks in the province led to government officials intervening to aid farmers with control measures aimed at preventing further losses. Because of the ability of the organism to persist in the environment for prolonged periods, an environmental risk or isolation survey was carried out in 2012 to determine the efficacy of control measures employed during the 2007-2008, anthrax outbreaks. No B. anthracis could be isolated from the old carcass sites, even when bone fragments from the carcasses were still clearly evident. This is an indication that the control measures and protocols were apparently successful in stemming the continuity of spore deposits at previously positive carcass sites.
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Affiliation(s)
- Ayesha Hassim
- Department of Veterinary Tropical Diseases, University of Pretoria.
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Bartoszewicz M, Czyżewska U. Spores and vegetative cells of phenotypically and genetically diverse Bacillus cereus sensu lato are common bacteria in fresh water of northeastern Poland. Can J Microbiol 2017; 63:939-950. [PMID: 28930645 DOI: 10.1139/cjm-2017-0337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Gram-positive rods Bacillus cereus sensu lato (sl) are common in natural habitats and food products. It is believed that they are restricted to spores; however, their ecology in aquatic habitats is still poorly investigated. Thus, the aim of the study was to assess the rain-dependent fluctuations in the concentration of B. cereus sl vegetative cells and spores, with evaluation of their phylogenetic and population structure in relation to the toxicity and psychrotolerance. We proved that vegetative cells of B. cereus sl are widely distributed in fresh water of rivers and lakes, being as common as spores. Moreover, heavy rain has a huge impact on their concentration in undisturbed environments. The diversity of B. cereus sl reflects the multiple sources of bacteria and the differences between their distinct environments. Next, their diverse genetic structure and phenotypes better fit their ecological properties than their taxonomic affiliation.
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Affiliation(s)
- Marek Bartoszewicz
- a Department of Microbiology, Institute of Biology, Faculty of Biology and Chemistry, University of Bialystok, 1J Ciolkowski Street, Bialystok 15-245, Poland
| | - Urszula Czyżewska
- b Department of Cytobiochemistry, Institute of Biology, Faculty of Biology and Chemistry, University of Bialystok, 1J Ciolkowski Street, Bialystok 15-245, Poland
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Maghsoudi S, Jalali E. Noble UV protective agent for Bacillus thuringiensis based on a combination of graphene oxide and olive oil. Sci Rep 2017; 7:11019. [PMID: 28887475 PMCID: PMC5591285 DOI: 10.1038/s41598-017-11080-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/14/2017] [Indexed: 11/08/2022] Open
Abstract
The focus of this study is investigating the performance of graphene oxide (GO) in the protective effect of olive oil on Bacillus thuringiensis (Bt) after being exposed to UV radiations. Biological pesticides Bt subsp. Kurstaki is one of the most important biological control agents. We compared the protective effect of two UV protectant; GO and olive oil and also the combination of both, on the stability of the formulation of Bt after exposure to UV radiations. Spore viability was measured for protective effect and bioassay test was performed on the formulations of Bt. The combination of GO and olive oil revealed the highest viabilities of 50.62% after 96 h exposure to UV radiation, while viabilities of free spore, olive oil formulation and GO formulation were 32.54%, 37.19%,and 45.20%, respectively. The mortality of irradiated combination formulation on second-instar larvae Ephestia Kuehniella was 68.89%, while the same parameter for free spore, olive oil formulation and GO formulation were 40%, 46.66%,and 56%, respectively.
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Affiliation(s)
- Shahab Maghsoudi
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran P.O. Box, 76169-133, Kerman, Iran.
| | - Elham Jalali
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran P.O. Box, 76169-133, Kerman, Iran
- Young Researchers Society, Shahid Bahonar University of Kerman, P.O. Box, 76175-133, Kerman, Iran
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Use of Red Beet (Beta vulgaris L.) for Antimicrobial Applications—a Critical Review. FOOD BIOPROCESS TECH 2017. [DOI: 10.1007/s11947-017-1942-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Saha RP, Samanta S, Patra S, Sarkar D, Saha A, Singh MK. Metal homeostasis in bacteria: the role of ArsR-SmtB family of transcriptional repressors in combating varying metal concentrations in the environment. Biometals 2017; 30:459-503. [PMID: 28512703 DOI: 10.1007/s10534-017-0020-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 02/02/2023]
Abstract
Bacterial infections cause severe medical problems worldwide, resulting in considerable death and loss of capital. With the ever-increasing rise of antibiotic-resistant bacteria and the lack of development of new antibiotics, research on metal-based antimicrobial therapy has now gained pace. Metal ions are essential for survival, but can be highly toxic to organisms if their concentrations are not strictly controlled. Through evolution, bacteria have acquired complex metal-management systems that allow them to acquire metals that they need for survival in different challenging environments while evading metal toxicity. Metalloproteins that controls these elaborate systems in the cell, and linked to key virulence factors, are promising targets for the anti-bacterial drug development. Among several metal-sensory transcriptional regulators, the ArsR-SmtB family displays greatest diversity with several distinct metal-binding and nonmetal-binding motifs that have been characterized. These prokaryotic metolloregulatory transcriptional repressors represses the expression of operons linked to stress-inducing concentrations of metal ions by directly binding to the regulatory regions of DNA, while derepression results from direct binding of metal ions by these homodimeric proteins. Many bacteria, e.g., Mycobacterium tuberculosis, Bacillus anthracis, etc., have evolved to acquire multiple metal-sensory motifs which clearly demonstrate the importance of regulating concentrations of multiple metal ions. Here, we discussed the mechanisms of how ArsR-SmtB family regulates the intracellular bioavailability of metal ions both inside and outside of the host. Knowledge of the metal-challenges faced by bacterial pathogens and their survival strategies will enable us to develop the next generation drugs.
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Affiliation(s)
- Rudra P Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India.
| | - Saikat Samanta
- Department of Microbiology, School of Science, Adamas University, Kolkata, 700126, India
| | - Surajit Patra
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Diganta Sarkar
- Department of Biotechnology, Techno India University, Kolkata, 700091, India
| | - Abinit Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Manoj Kumar Singh
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
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