1
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Schmid PJ, Forstner P, Kittinger C. Sliding motility of Bacillus cereus mediates vancomycin pseudo-resistance during antimicrobial susceptibility testing. J Antimicrob Chemother 2024; 79:1628-1636. [PMID: 38785365 PMCID: PMC11215547 DOI: 10.1093/jac/dkae156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND The glycopeptide vancomycin is the antimicrobial agent-of-choice for the treatment of severe non-gastrointestinal infections with members of Bacillus cereus sensu lato (s.l.). Recently, sporadic detection of vancomycin-resistant phenotypes emerged, mostly for agar diffusion testing such as the disc diffusion method or gradient test (e.g. Etest®) method. RESULTS In this work, we were able to disprove a preliminarily assumed high resistance to vancomycin in an isolate of B. cereus s.l. using broth microdilution and agar dilution. Microscopic imaging during vancomycin susceptibility testing showed spreading towards the inhibition zone, which strongly suggested sliding motility. Furthermore, transcriptomic analysis using RNA-Seq on the nanopore platform revealed several key genes of biofilm formation (e.g. calY, tasA, krsEABC) to be up-regulated in pseudo-resistant cells, substantiating that bacterial sliding is responsible for the observed mobility. Down-regulation of virulence (e.g. hblABCD, nheABC, plcR) and flagellar genes compared with swarming cells also confirmed the non-swarming phenotype of the pseudo-resistant isolate. CONCLUSIONS The results highlight an insufficiency of agar diffusion testing for vancomycin susceptibility in the B. cereus group, and reference methods like broth microdilution are strongly recommended. As currently no guideline mentions interfering phenotypes in antimicrobial susceptibility testing of B. cereus s.l., this knowledge is essential to obtain reliable results on vancomycin susceptibility. In addition, this is the first report of sliding motility undermining accurate antimicrobial susceptibility testing in B. cereus s.l. and may serve as a basis for future studies on bacterial motility in susceptibility testing and its potential impact on treatment efficacy.
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Affiliation(s)
- Paul J Schmid
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Diagnostic and Research Center for Molecular Biomedicine, Medical University of Graz, Graz, Austria
| | - Patrick Forstner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Diagnostic and Research Center for Molecular Biomedicine, Medical University of Graz, Graz, Austria
| | - Clemens Kittinger
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Diagnostic and Research Center for Molecular Biomedicine, Medical University of Graz, Graz, Austria
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2
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Xiang SL, Xu KZ, Yin LJ, Jia AQ. An Investigation of Quorum Sensing Inhibitors against Bacillus cereus in The Endophytic Fungus Pithomyces sacchari of the Laurencia sp. Mar Drugs 2024; 22:161. [PMID: 38667778 PMCID: PMC11051030 DOI: 10.3390/md22040161] [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: 02/21/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Bacillus cereus, a common food-borne pathogen, forms biofilms and generates virulence factors through a quorum sensing (QS) mechanism. In this study, six compounds (dankasterone A, demethylincisterol A3, zinnimidine, cyclo-(L-Val-L-Pro), cyclo-(L-Ile-L-Pro), and cyclo-(L-Leu-L-Pro)) were isolated from the endophytic fungus Pithomyces sacchari of the Laurencia sp. in the South China Sea. Among them, demethylincisterol A3, a sterol derivative, exhibited strong QS inhibitory activity against B. cereus. The QS inhibitory activity of demethylincisterol A3 was evaluated through experiments. The minimum inhibitory concentration (MIC) of demethylincisterol A3 against B. cereus was 6.25 μg/mL. At sub-MIC concentrations, it significantly decreased biofilm formation, hindered mobility, and diminished the production of protease and hemolysin activity. Moreover, RT-qPCR results demonstrated that demethylincisterol A3 markedly inhibited the expression of QS-related genes (plcR and papR) in B. cereus. The exposure to demethylincisterol A3 resulted in the downregulation of genes (comER, tasA, rpoN, sinR, codY, nheA, hblD, and cytK) associated with biofilm formation, mobility, and virulence factors. Hence, demethylincisterol A3 is a potentially effective compound in the pipeline of innovative antimicrobial therapies.
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Affiliation(s)
| | | | | | - Ai-Qun Jia
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou 570228, China
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3
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Sun Y, Shuai W, Nie L, Li X, Jiang L. Investigating the Role of OrbF in Biofilm Biosynthesis and Regulation of Biofilm-Associated Genes in Bacillus cereus BC1. Foods 2024; 13:638. [PMID: 38472751 DOI: 10.3390/foods13050638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 03/14/2024] Open
Abstract
Bacillus cereus (B. cereus), a prevalent foodborne pathogen, constitutes a substantial risk to food safety due to its pronounced resilience under adverse environmental conditions such as elevated temperatures and ultraviolet radiation. This resilience can be attributed to its capacity for biofilm synthesis and sustained high viability. Our research aimed to elucidate the mechanisms governing biofilm biosynthesis in B. cereus. To this end, we constructed a 5088-mutant library of the B. cereus strain BC1 utilizing the transposon TnYLB-1. Systematic screening of this library yielded mutants exhibiting diminished biofilm formation capabilities. Twenty-four genes associated with the biofilm synthesis were identified by reverse PCR in these mutants, notably revealing a significant reduction in biofilm synthesis upon disruption of the orbF gene in B. cereus BC1. Comparative analysis between the wild type and orbF-deficient BC1 strains (BC1ΔorbF) indicated a marked downregulation (decreased by 11.7% to 96.7%) in the expression of genes implicated in biofilm formation, flagellar assembly, and bacterial chemotaxis in the BC1ΔorbF. Electrophoretic mobility shift assay (EMSA) further corroborated the role of OrbF, demonstrating its binding to the promoter region of the biofilm gene cluster, subsequently leading to the suppression of transcriptional activity of biofilm-associated genes in B. cereus BC1. Our findings underscore the pivotal role of orbF in biofilm biosynthesis in B. cereus, highlighting its potential as a target for strategies aimed at mitigating biofilm formation in this pathogen.
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Affiliation(s)
- Yang Sun
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Wenjing Shuai
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Lanmengya Nie
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Xiangfei Li
- Engineering Laboratory for Industrial Microbiology Molecular Beeding of Anhui Province, College of Biologic & Food Engineering, Anhui Polytechnic University, 8 Middle Beijing Road, Wuhu 241000, China
| | - Ling Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
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4
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Catania AM, Di Ciccio P, Ferrocino I, Civera T, Cannizzo FT, Dalmasso A. Evaluation of the biofilm-forming ability and molecular characterization of dairy Bacillus spp. isolates. Front Cell Infect Microbiol 2023; 13:1229460. [PMID: 37600945 PMCID: PMC10432688 DOI: 10.3389/fcimb.2023.1229460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/14/2023] [Indexed: 08/22/2023] Open
Abstract
Food processing lines represents a suitable environment for bacterial biofilm formation. One of the most common biofilm-forming genera in dairy processing plants is Bacillus, which includes species that may have a negative impact on safety and/or quality of dairy products. In the current study, we evaluated the biofilm forming ability and molecular characteristics of dairy Bacillus spp. isolates (B. cereus and B. subtilis). Reference strains (B. cereus ATCC 14579 and B. subtilis NCTC 3610) were also included in the experiment. All isolates were screened by micro-titer plate (96 wells) to assess their ability to form biofilm. Then, they were tested on two common food contact surfaces (polystyrene and stainless steel) by using 6-well plates and AISI 316 stainless steel coupons. Biofilm formation, expressed as biofilm production index (BPI), was higher on polystyrene than stainless steel (except for B. cereus ATCC 14579). These observations were further confirmed by scanning electron microscopy, which allowed the microscopy observation of biofilm structure. Moreover, a possible correlation among total viable cell counts (CFU) and BPI was examined, as well as a connection among biofilm formation and bacterial cell hydrophobicity. Finally, whole genome sequencing was performed highlighting a genetic similarity among the strains belonging to the same species. The presence of selected genes involved in biofilm formation was also examined showing that strains with a greater presence of these genes were able to produce more biofilm in the tested materials. Additionally, for B. cereus strains enterotoxin genes were detected.
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Affiliation(s)
- Angela Maria Catania
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, Grugliasco, Turin, Italy
| | - Pierluigi Di Ciccio
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, Grugliasco, Turin, Italy
| | - Ilario Ferrocino
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo P. Braccini 2, Grugliasco, Turin, Italy
| | - Tiziana Civera
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, Grugliasco, Turin, Italy
| | | | - Alessandra Dalmasso
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, Grugliasco, Turin, Italy
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5
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Kulkova I, Dobrzyński J, Kowalczyk P, Bełżecki G, Kramkowski K. Plant Growth Promotion Using Bacillus cereus. Int J Mol Sci 2023; 24:ijms24119759. [PMID: 37298706 DOI: 10.3390/ijms24119759] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 05/25/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
Plant growth-promoting bacteria (PGPB) appear to be a sensible competitor to conventional fertilization, including mineral fertilizers and chemical plant protection products. Undoubtedly, one of the most interesting bacteria exhibiting plant-stimulating traits is, more widely known as a pathogen, Bacillus cereus. To date, several environmentally safe strains of B. cereus have been isolated and described, including B. cereus WSE01, MEN8, YL6, SA1, ALT1, ERBP, GGBSTD1, AK1, AR156, C1L, and T4S. These strains have been studied under growth chamber, greenhouse, and field conditions and have shown many significant traits, including indole-3-acetic acid (IAA) and aminocyclopropane-1-carboxylic acid (ACC) deaminase production or phosphate solubilization, which allows direct plant growth promotion. It includes an increase in biometrics traits, chemical element content (e.g., N, P, and K), and biologically active substances content or activity, e.g., antioxidant enzymes and total soluble sugar. Hence, B. cereus has supported the growth of plant species such as soybean, maize, rice, and wheat. Importantly, some B. cereus strains can also promote plant growth under abiotic stresses, including drought, salinity, and heavy metal pollution. In addition, B. cereus strains produced extracellular enzymes and antibiotic lipopeptides or triggered induced systemic resistance, which allows indirect stimulation of plant growth. As far as biocontrol is concerned, these PGPB can suppress the development of agriculturally important phytopathogens, including bacterial phytopathogens (e.g., Pseudomonas syringae, Pectobacterium carotovorum, and Ralstonia solanacearum), fungal phytopathogens (e.g., Fusarium oxysporum, Botrytis cinerea, and Rhizoctonia solani), and other phytopathogenic organisms (e.g., Meloidogyne incognita (Nematoda) and Plasmodiophora brassicae (Protozoa)). In conclusion, it should be noted that there are still few studies on the effectiveness of B. cereus under field conditions, particularly, there is a lack of comprehensive analyses comparing the PGP effects of B. cereus and mineral fertilizers, which should be reduced in favor of decreasing the use of mineral fertilizers. It is also worth mentioning that there are still very few studies on the impact of B. cereus on the indigenous microbiota and its persistence after application to soil. Further studies would help to understand the interactions between B. cereus and indigenous microbiota, subsequently contributing to increasing its effectiveness in promoting plant growth.
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Affiliation(s)
- Iryna Kulkova
- Institute of Technology and Life Sciences-National Research Institute, Falenty, 3 Hrabska Avenue, 05-090 Raszyn, Poland
| | - Jakub Dobrzyński
- Institute of Technology and Life Sciences-National Research Institute, Falenty, 3 Hrabska Avenue, 05-090 Raszyn, Poland
| | - Paweł Kowalczyk
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110 Jabłonna, Poland
| | - Grzegorz Bełżecki
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110 Jabłonna, Poland
| | - Karol Kramkowski
- Department of Physical Chemistry, Medical University of Białystok, Kilińskiego 1 Str., 15-089 Białystok, Poland
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6
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Yin G, Peng A, Zhang L, Wang Y, Du G, Chen J, Kang Z. Design of artificial small regulatory trans-RNA for gene knockdown in Bacillus subtilis. Synth Syst Biotechnol 2022; 8:61-68. [DOI: 10.1016/j.synbio.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
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7
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Yang W, Yan H, Dong G, Li Z, Jiang C, Gu D, Niu D, Zhou D, Luo Y. Comparative transcriptomics reveal different genetic adaptations of biofilm formation in Bacillus subtilis isolate 1JN2 in response to Cd2+ treatment. Front Microbiol 2022; 13:1002482. [PMID: 36267191 PMCID: PMC9577173 DOI: 10.3389/fmicb.2022.1002482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/05/2022] [Indexed: 12/01/2022] Open
Abstract
Biofilm plays important roles in the life cycle of Bacillus species, such as promoting host and object surface colonization and resisting heavy metal stress. This study utilized transcriptomics to evaluate the impacts of cadmium on the components, morphology, and function of biofilms of Bacillus subtilis strain 1JN2. Under cadmium ion stress, the morphology of the B. subtilis 1JN2 biofilm was flattened, and its mobility increased. Moreover, differential gene expression analysis showed that the main regulator of biofilm formation, Spo0A, decreased in expression under cadmium ion stress, thereby inhibiting extracellular polysaccharide synthesis through the SinI/SinR two-component regulatory system and the AbrB pathway. Cadmium ion treatment also increased the SigD content significantly, thereby increasing the expression of the flagella encoding and assembly genes in the strain. This promoted poly-γ-glutamic acid production via the DegS/DegU two-component regulatory system and the conversion of biofilm extracellular polysaccharide to poly-γ-glutamic acid. This conferred cadmium stress tolerance in the strain. Additionally, the cadmium ion-mediated changes in the biofilm composition affected the colonization of the strain on the host plant root surface. Cadmium ions also induced surfactin synthesis. These findings illustrate the potential of Bacillus species as biocontrol strains that can mitigate plant pathogenic infections and heavy metal stress. The results also provide a basis for the screening of multifunctional biocontrol strains.
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Affiliation(s)
- Wei Yang
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
| | - Haixia Yan
- Agro-Tech Extension and Service Center, Huai’an, China
| | - Guanghui Dong
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Zhengpeng Li
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
| | - Chunhao Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Dalu Gu
- Huaiyin Institute of Agricultural Sciences of Xuhuai Region in Jiangsu, Huaian Academy of Agricultural Sciences, Huai’an, China
| | - Dongdong Niu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Danni Zhou
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Yuming Luo
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
- *Correspondence: Yuming Luo,
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8
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Xu S, Cao Q, Liu Z, Chen J, Yan P, Li B, Xu Y. Transcriptomic Analysis Reveals the Role of tmRNA on Biofilm Formation in Bacillus subtilis. Microorganisms 2022; 10:microorganisms10071338. [PMID: 35889057 PMCID: PMC9319509 DOI: 10.3390/microorganisms10071338] [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: 06/09/2022] [Revised: 06/30/2022] [Accepted: 06/30/2022] [Indexed: 11/16/2022] Open
Abstract
Bacillus strains are widely distributed in terrestrial and marine environments, and some of them are used as biocontrol organisms for their biofilm-formation ability. In Bacillus subtilis, biofilm formation is fine-tuned by a complex network, a clear understanding of which still requires study. In bacteria, tmRNA, encoded by the ssrA gene, catalyzes trans-translation that can rescue ribosomes stalled on mRNA transcripts lacking a functional stop codon. tmRNA also affects physiological bioprocesses in some bacteria. In this study, we constructed a ssrA mutant in B. subtilis and found that the biofilm formation in the ssrA mutant was largely impaired. Moreover, we isolated a biofilm-formation suppressor of ssrA, in which the biofilm formation was restored to a level even stronger than that in the wild type. We further performed RNAseq assays with the wild type, ssrA mutant, and suppressor of ssrA for comparisons of their transcriptomes. By analyzing the transcriptomic data, we predicted the possible functions of some differentially expressed genes (DEGs) in the tmRNA regulation of biofilm formation in B. subtilis. Finally, we found that the overexpression of two DEGs, acoA and yhjR, could restore the biofilm formation in the ssrA mutant, indicating that AcoA and YhjR were immediate regulators involved in the tmRNA regulatory web controlling biofilm formation in B. subtilis. Our data can improve the knowledge about the molecular network involved in Bacillus biofilm formation and provide new targets for manipulation of Bacillus biofilms for future investigation.
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Affiliation(s)
- Shanshan Xu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China; (S.X.); (Q.C.); (Z.L.); (J.C.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;
| | - Qianqian Cao
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China; (S.X.); (Q.C.); (Z.L.); (J.C.)
| | - Zengzhi Liu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China; (S.X.); (Q.C.); (Z.L.); (J.C.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;
| | - Junpeng Chen
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China; (S.X.); (Q.C.); (Z.L.); (J.C.)
| | - Peiguang Yan
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;
| | - Bingyu Li
- Guangdong Key Laboratory for Genome Stability and Disease Prevention, Health Science Center, Shenzhen University, Shenzhen 518055, China
- Correspondence: (B.L.); (Y.X.)
| | - Ying Xu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China; (S.X.); (Q.C.); (Z.L.); (J.C.)
- Correspondence: (B.L.); (Y.X.)
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9
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Lamba S, Mundanda Muthappa D, Fanning S, Scannell AGM. Sporulation and Biofilms as Survival Mechanisms of Bacillus Species in Low-Moisture Food Production Environments. Foodborne Pathog Dis 2022; 19:448-462. [PMID: 35819266 DOI: 10.1089/fpd.2022.0006] [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: 11/13/2022] Open
Abstract
Low-moisture foods (LMF) have clear advantages with respect to limiting the growth of foodborne pathogens. However, the incidences of Bacillus species in LMF reported in recent years raise concerns about food quality and safety, particularly when these foods are used as ingredients in more complex higher moisture products. This literature review describes the interlinked pathways of sporulation and biofilm formation by Bacillus species and their underlying molecular mechanisms that contribute to the bacteriums' persistence in LMF production environments. The long-standing challenges of food safety and quality in the LMF industry are also discussed with a focus on the bakery industry.
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Affiliation(s)
- Sakshi Lamba
- UCD Institute of Food and Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD Centre for Food Safety, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD School of Agriculture and Food Science, and Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Dechamma Mundanda Muthappa
- UCD Centre for Food Safety, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD School of Agriculture and Food Science, and Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- UCD Institute of Food and Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD Centre for Food Safety, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Amalia G M Scannell
- UCD Institute of Food and Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD Centre for Food Safety, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.,UCD School of Agriculture and Food Science, and Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
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10
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Jiang A, Zou C, Xu X, Ke Z, Hou J, Jiang G, Fan C, Gong J, Wei J. Complete genome sequence of biocontrol strain Paenibacillus peoriae HJ-2 and further analysis of its biocontrol mechanism. BMC Genomics 2022; 23:161. [PMID: 35209846 PMCID: PMC8876185 DOI: 10.1186/s12864-022-08330-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/19/2022] [Indexed: 01/25/2023] Open
Abstract
Background Paris polyphylla is a herb widely used in traditional Chinese medicine to treat various diseases. Stem rot diseases seriously affected the yield of P. polyphylla in subtropical areas of China. Therefore, cost-effective, chemical-free, eco-friendly strategies to control stem rot on P. polyphylla are valuable and urgently needed. Results In this paper, we reported the biocontrol efficiency of Paenibacillus peoriae HJ-2 and its complete genome sequence. Strain HJ-2 could serve as a potential biocontrol agent against stem rot on P. polyphylla in the greenhouse and field. The genome of HJ-2 consists of a single 6,001,192 bp chromosome with an average GC content of 45% and 5,237 predicted protein coding genes, 39 rRNAs and 108 tRNAs. The phylogenetic tree indicated that HJ-2 is most closely related to P. peoriae IBSD35. Functional analysis of genome revealed numerous genes/gene clusters involved in plant colonization, biofilm formation, plant growth promotion, antibiotic and resistance inducers synthesis. Moreover, metabolic pathways that potentially contribute to biocontrol mechanisms were identified. Conclusions This study revealed that P. peoriae HJ-2 could serve as a potential BCA against stem rot on P. polyphylla. Based on genome analysis, the genome of HJ-2 contains more than 70 genes and 12 putative gene clusters related to secondary metabolites, which have previously been described as being involved in chemotaxis motility, biofilm formation, growth promotion, antifungal activity and resistance inducers biosynthesis. Compared with other strains, variation in the genes/gene clusters may lead to different antimicrobial spectra and biocontrol efficacies. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08330-0.
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Affiliation(s)
- Aiming Jiang
- College of Agriculture, Guangxi University, Nanning, 530004, China.,College of Chemistry and Environmental Engineering, Hanjiang Normal University, Shiyan, 442000, China
| | - Chengwu Zou
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Xiang Xu
- Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China
| | - Zunwei Ke
- College of Chemistry and Environmental Engineering, Hanjiang Normal University, Shiyan, 442000, China
| | - Jiangan Hou
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Guihe Jiang
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Chunli Fan
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Jianhua Gong
- College of Chemistry and Environmental Engineering, Hanjiang Normal University, Shiyan, 442000, China
| | - Jiguang Wei
- College of Agriculture, Guangxi University, Nanning, 530004, China.
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11
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Lin Y, Briandet R, Kovács ÁT. Bacillus cereus sensu lato biofilm formation and its ecological importance. Biofilm 2022; 4:100070. [PMID: 35243332 PMCID: PMC8861577 DOI: 10.1016/j.bioflm.2022.100070] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 12/20/2022] Open
Abstract
Biofilm formation is a ubiquitous process of bacterial communities that enables them to survive and persist in various environmental niches. The Bacillus cereus group includes phenotypically diversified species that are widely distributed in the environment. Often, B. cereus is considered a soil inhabitant, but it is also commonly isolated from plant roots, nematodes, and food products. Biofilms differ in their architecture and developmental processes, reflecting adaptations to specific niches. Importantly, some B. cereus strains are foodborne pathogens responsible for two types of gastrointestinal diseases, diarrhea and emesis, caused by distinct toxins. Thus, the persistency of biofilms is of particular concern for the food industry, and understanding the underlying mechanisms of biofilm formation contributes to cleaning procedures. This review focuses on the genetic background underpinning the regulation of biofilm development, as well as the matrix components associated with biofilms. We also reflect on the correlation between biofilm formation and the development of highly resistant spores. Finally, advances in our understanding of the ecological importance and evolution of biofilm formation in the B. cereus group are discussed.
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Huang R, Feng H, Xu Z, Zhang N, Liu Y, Shao J, Shen Q, Zhang R. Identification of Adhesins in Plant Beneficial Rhizobacteria Bacillus velezensis SQR9 and Their Effect on Root Colonization. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:64-72. [PMID: 34698535 DOI: 10.1094/mpmi-09-21-0234-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Probiotic Bacillus colonization of plant root surfaces has been reported to improve its beneficial effect. Chemotaxis, adhesion, aggregation, and biofilm formation are the four steps of root colonization by plant growth-promoting rhizobacteria (PGPRs). Compared with the other three well-studied processes, adhesion of PGPRs is less known. In this study, using mutant strains deleted for potential adhesin genes in PGPR strain Bacillus velezensis SQR9, adherence to both cucumber root surface and abiotic surface by those strains was evaluated. Results showed that deletion mutations ΔlytB, ΔV529_10500, ΔfliD, ΔyhaN, and ΔsacB reduced the adhesion to root surfaces, while, among them, only ΔfliD had significant defects in adhesion to abiotic surfaces (glass and polystyrene). In addition, B. velevzensis SQR9 mutants defective in adhesion to root surfaces showed a deficiency in rhizosphere colonization. Among the encoded proteins, FliD and YhaN played vital roles in root adhesion. This research systematically explored the potential adhesins in a well-studied PGPR strain and also indicated that adhesion progress was required for root colonization, which will help to enhance rhizosphere colonization and beneficial function of PGPRs in agricultural production.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Rong Huang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Haichao Feng
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Zhihui Xu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Nan Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Yunpeng Liu
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
| | - Jiahui Shao
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Ruifu Zhang
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
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Schoenborn AA, Yannarell SM, Wallace ED, Clapper H, Weinstein IC, Shank EA. Defining the Expression, Production, and Signaling Roles of Specialized Metabolites during Bacillus subtilis Differentiation. J Bacteriol 2021; 203:e0033721. [PMID: 34460312 PMCID: PMC8544424 DOI: 10.1128/jb.00337-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/11/2021] [Indexed: 11/20/2022] Open
Abstract
Bacterial specialized (or secondary) metabolites are structurally diverse molecules that mediate intra- and interspecies interactions by altering growth and cellular physiology and differentiation. Bacillus subtilis, a Gram-positive model bacterium commonly used to study biofilm formation and sporulation, has the capacity to produce more than 10 specialized metabolites. Some of these B. subtilis specialized metabolites have been investigated for their role in facilitating cellular differentiation, but only rarely has the behavior of multiple metabolites been simultaneously investigated. In this study, we explored the interconnectivity of differentiation (biofilm and sporulation) and specialized metabolites in B. subtilis. Specifically, we interrogated how development influences specialized metabolites and vice versa. Using the sporulation-inducing medium DSM, we found that the majority of the specialized metabolites examined are expressed and produced during biofilm formation and sporulation. Additionally, we found that six of these metabolites (surfactin, ComX, bacillibactin, bacilysin, subtilosin A, and plipastatin) are necessary signaling molecules for proper progression of B. subtilis differentiation. This study further supports the growing body of work demonstrating that specialized metabolites have essential physiological functions as cell-cell communication signals in bacteria. IMPORTANCE Bacterially produced specialized metabolites are frequently studied for their potential use as antibiotics and antifungals. However, a growing body of work has suggested that the antagonistic potential of specialized metabolites is not their only function. Here, using Bacillus subtilis as our model bacterium, we demonstrated that developmental processes such as biofilm formation and sporulation are tightly linked to specialized metabolite gene expression and production. Additionally, under our differentiation-inducing conditions, six out of the nine specialized metabolites investigated behave as intraspecific signals that impact B. subtilis physiology and influence biofilm formation and sporulation. Our work supports the viewpoint that specialized metabolites have a clear role as cell-cell signaling molecules within differentiated populations of bacteria.
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Affiliation(s)
- Alexi A. Schoenborn
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sarah M. Yannarell
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - E. Diane Wallace
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Haley Clapper
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ilon C. Weinstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Elizabeth A. Shank
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Draft genome sequencing and functional annotation and characterization of biofilm-producing bacterium Bacillus novalis PD1 isolated from rhizospheric soil. Antonie van Leeuwenhoek 2021; 114:1977-1989. [PMID: 34537868 DOI: 10.1007/s10482-021-01655-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/06/2021] [Indexed: 10/20/2022]
Abstract
Biofilm forming bacterium Bacillus novalis PD1 was isolated from the rhizospheric soil of a paddy field. B. novalis PD1 is a Gram-positive, facultatively anaerobic, motile, slightly curved, round-ended, and spore-forming bacteria. The isolate B. novalis PD1 shares 98.45% similarity with B. novalis KB27B. B. vireti LMG21834 and B. drentensis NBRC 102,427 are the closest phylogenetic neighbours for B. novalis PD1. The draft genome RAST annotation showed a linear chromosome with 4,569,088 bp, encoding 6139 coding sequences, 70 transfer RNA (tRNA), and 11 ribosomal RNA (rRNA) genes. The genomic annotation of biofilm forming B. novalis PD1(> 3.6@OD595nm) showed the presence of exopolysaccharide-forming genes (ALG, PSL, and PEL) as well as other biofilm-related genes (comER, Spo0A, codY, sinR, TasA, sipW, degS, and degU). Antibiotic inactivation gene clusters (ANT (6)-I, APH (3')-I, CatA15/A16 family), efflux pumps conferring antibiotic resistance genes (BceA, BceB, MdtABC-OMF, MdtABC-TolC, and MexCD-OprJ), and secondary metabolites linked to phenazine, terpene, and beta lactone gene clusters are part of the genome.
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Torasso Kasem EJ, Angelov A, Werner E, Lichev A, Vanderhaeghen S, Liebl W. Identification of New Chromosomal Loci Involved in com Genes Expression and Natural Transformation in the Actinobacterial Model Organism Micrococcus luteus. Genes (Basel) 2021; 12:genes12091307. [PMID: 34573289 PMCID: PMC8467076 DOI: 10.3390/genes12091307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/18/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022] Open
Abstract
Historically, Micrococcus luteus was one of the first organisms used to study natural transformation, one of the main routes of horizontal gene transfer among prokaryotes. However, little is known about the molecular basis of competence development in M. luteus or any other representative of the phylum of high-GC Gram-positive bacteria (Actinobacteria), while this means of genetic exchange has been studied in great detail in Gram-negative and low-GC Gram-positive bacteria (Firmicutes). In order to identify new genetic elements involved in regulation of the comEA-comEC competence operon in M. luteus, we conducted random chemical mutagenesis of a reporter strain expressing lacZ under the control of the comEA-comEC promoter, followed by the screening of dysregulated mutants. Mutants with (i) upregulated com promoter under competence-repressing conditions and (ii) mutants with a repressed com promoter under competence-inducing conditions were isolated. After genotype and phenotype screening, the genomes of several mutant strains were sequenced. A selection of putative com-influencing mutations was reinserted into the genome of the M. luteus reporter strain as markerless single-nucleotide mutations to confirm their effect on com gene expression. This strategy revealed mutations affecting com gene expression at genetic loci different from previously known genes involved in natural transformation. Several of these mutations decreased transformation frequencies by several orders of magnitude, thus indicating significant roles in competence development or DNA acquisition in M. luteus. Among the identified loci, there was a new locus containing genes with similarity to genes of the tad clusters of M. luteus and other bacteria.
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Affiliation(s)
- Enzo Joaquin Torasso Kasem
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
| | - Angel Angelov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
- Institute of Medical Microbiology and Hygiene, University Clinic Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Elisa Werner
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
| | - Antoni Lichev
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
| | - Sonja Vanderhaeghen
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising, Germany; (E.J.T.K.); (A.A.); (E.W.); (A.L.); (S.V.)
- Correspondence: ; Tel.: +49-81-6171-545
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Ding H, Mo W, Yu S, Cheng H, Peng L, Liu Z. Whole Genome Sequence of Bacillus velezensis Strain GUMT319: A Potential Biocontrol Agent Against Tobacco Black Shank Disease. Front Microbiol 2021; 12:658113. [PMID: 34295312 PMCID: PMC8291047 DOI: 10.3389/fmicb.2021.658113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
Phytophthora nicotianae causes black shank, a serious soil-borne disease, in tobacco. In this study, the Bacillus strain GUMT319 was isolated from the rhizosphere of healthy tobacco plants grown in a field in Guizhou with a high incidence of tobacco black shank. Genome sequencing revealed that GUMT319 contained a single circular chromosome 3,940,023 bp in length, with 4,053 predicted genes and an average GC content of 46.6%. Based on phylogenomic analyses, GUMT319 was designated as Bacillus velezensis. The genome of GUMT319 contained more than 60 genes and 13 gene clusters that have previously been found to be active in antifungal mechanisms, biofilm formation, and chemotaxis motility. Additionally, confocal laser scanning microscopy and scanning electron microscopy showed that GUMT319 formed a spatially organized biofilm in vivo. In addition, lauric acid negatively regulated biofilm formation. This is the first study to report that nicotine in tobacco root exudates was a chemoattractant for biocontrol Bacillus strains. In this study, we identified new interactions between beneficial microorganisms and tobacco roots in the rhizosphere. Moreover, dual culture tests in vitro showed that GUMT319 inhibited the growth of P. nicotianae and also displayed inhibitory effects against eight other plant pathogens, namely, Colletotrichum scovillei, Colletotrichum capsici, Fusarium carminascens, Sclerotinia sclerotiorum, Alternaria alternata, Phomopsis sp., Phyllosticta sorghina, and Exserohilum turcicum. Furthermore, GUMT319 exhibited > 70% control efficiency against tobacco black shank in field experiments conducted in 2018–2020. Thus, GUMT319 was more effective in controlling the incidence of tobacco black shank than other treatments including fungicide application. Overall, these results suggested that GUMT319 (B. velezensis) could be used as a potential biocontrol agent against tobacco black shank.
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Affiliation(s)
- Haixia Ding
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China.,Guizhou Academy of Agricultural Sciences, Guiyang, China
| | - Weidi Mo
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Shui Yu
- College of Tobacco Science, Guizhou University, Guiyang, China
| | - Huanhuan Cheng
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Lijuan Peng
- College of Tobacco Science, Guizhou University, Guiyang, China
| | - Zuoyi Liu
- Guizhou Academy of Agricultural Sciences, Guiyang, China.,Guizhou Key Laboratory of Agricultural Biotechnology, Guizhou Academy of Agricultural Sciences, Guiyang, China
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Hu WS, Woo DU, Kang YJ, Koo OK. Biofilm and Spore Formation of Clostridium perfringens and Its Resistance to Disinfectant and Oxidative Stress. Antibiotics (Basel) 2021; 10:antibiotics10040396. [PMID: 33917564 PMCID: PMC8067515 DOI: 10.3390/antibiotics10040396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/05/2021] [Accepted: 04/01/2021] [Indexed: 11/24/2022] Open
Abstract
Clostridium perfringens is a major human pathogen that causes gastroenteritis via enterotoxin production and has the ability to form spores and biofilms for environmental persistence and disease transmission. This study aimed to compare the disinfectant and environmental resistance properties of C. perfringens vegetative cells and spores in planktonic and sessile conditions, and to examine the nucleotide polymorphisms and transcription under sessile conditions in C. perfringens strains isolated from meat. The sporulation rate of sessile C. perfringens TYJAM-D-66 (cpe+) was approximately 19% at day 5, while those of CMM-C-80 (cpe−) and SDE-B-202 (cpe+) were only 0.26% and 0.67%, respectively, at day 7. When exposed to aerobic conditions for 36 h, TYJAM-D-66, CMM-C-80, and SDE-B-202 vegetative cells showed 1.70 log, 5.36 log, and 5.67 log reductions, respectively. After treatment with sodium hypochlorite, the survival rates of TYJAM-D-66 vegetative cells (53.6%) and spores (82.3%) in biofilms were higher than those of planktonic cells (9.23%). Biofilm- and spore-related genes showed different expression within TYJAM-D-66 (–4.66~113.5), CMM-C-80 (–3.02~2.49), and SDE-B-202 (–5.07~2.73). Our results indicate the resistance of sessile cells and spores of C. perfringens upon exposure to stress conditions after biofilm formation.
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Affiliation(s)
- Wen Si Hu
- Department of Food Science and Engineering, Liaocheng University, Liaocheng 252059, China;
| | - Dong U Woo
- Division of Life Science Department, Gyeongsang National University, Jinju 52828, Korea; (D.U.W.); (Y.J.K.)
- Division of Bio & Medical Big Data Department (BK4 Program), Gyeongsang National University, Jinju 52828, Korea
| | - Yang Jae Kang
- Division of Life Science Department, Gyeongsang National University, Jinju 52828, Korea; (D.U.W.); (Y.J.K.)
- Division of Bio & Medical Big Data Department (BK4 Program), Gyeongsang National University, Jinju 52828, Korea
| | - Ok Kyung Koo
- Department of Food and Nutrition, Gyeongsang National University, Jinju 52828, Korea
- Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea
- Correspondence: ; Tel.: +82-55-772-1441
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Phenotypic properties and genotyping analysis of Bacillus cereus group isolates from dairy and potato products. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.110853] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Autotransporters Drive Biofilm Formation and Autoaggregation in the Diderm Firmicute Veillonella parvula. J Bacteriol 2020; 202:JB.00461-20. [PMID: 32817093 PMCID: PMC7549365 DOI: 10.1128/jb.00461-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
Veillonella parvula is an anaerobic commensal and opportunistic pathogen whose ability to adhere to surfaces or other bacteria and form biofilms is critical for it to inhabit complex human microbial communities such as the gut and oral microbiota. Although the adhesive capacity of V. parvula has been previously described, very little is known about the underlying molecular mechanisms due to a lack of genetically amenable Veillonella strains. In this study, we took advantage of a naturally transformable V. parvula isolate and newly adapted genetic tools to identify surface-exposed adhesins called autotransporters as the main molecular determinants of adhesion in this bacterium. This work therefore provides new insights on an important aspect of the V. parvula lifestyle, opening new possibilities for mechanistic studies of the contribution of biofilm formation to the biology of this major commensal of the oral-digestive tract. The Negativicutes are a clade of the Firmicutes that have retained the ancestral diderm character and possess an outer membrane. One of the best studied Negativicutes, Veillonella parvula, is an anaerobic commensal and opportunistic pathogen inhabiting complex human microbial communities, including the gut and the dental plaque microbiota. Whereas the adhesion and biofilm capacities of V. parvula are expected to be crucial for its maintenance and development in these environments, studies of V. parvula adhesion have been hindered by the lack of efficient genetic tools to perform functional analyses in this bacterium. Here, we took advantage of a recently described naturally transformable V. parvula isolate, SKV38, and adapted tools developed for the closely related Clostridia spp. to perform random transposon and targeted mutagenesis to identify V. parvula genes involved in biofilm formation. We show that type V secreted autotransporters, typically found in diderm bacteria, are the main determinants of V. parvula autoaggregation and biofilm formation and compete with each other for binding either to cells or to surfaces, with strong consequences for V. parvula biofilm formation capacity. The identified trimeric autotransporters have an original structure compared to classical autotransporters identified in Proteobacteria, with an additional C-terminal domain. We also show that inactivation of the gene coding for a poorly characterized metal-dependent phosphohydrolase HD domain protein conserved in the Firmicutes and their closely related diderm phyla inhibits autotransporter-mediated biofilm formation. This study paves the way for further molecular characterization of V. parvula interactions with other bacteria and the host within complex microbiota environments. IMPORTANCEVeillonella parvula is an anaerobic commensal and opportunistic pathogen whose ability to adhere to surfaces or other bacteria and form biofilms is critical for it to inhabit complex human microbial communities such as the gut and oral microbiota. Although the adhesive capacity of V. parvula has been previously described, very little is known about the underlying molecular mechanisms due to a lack of genetically amenable Veillonella strains. In this study, we took advantage of a naturally transformable V. parvula isolate and newly adapted genetic tools to identify surface-exposed adhesins called autotransporters as the main molecular determinants of adhesion in this bacterium. This work therefore provides new insights on an important aspect of the V. parvula lifestyle, opening new possibilities for mechanistic studies of the contribution of biofilm formation to the biology of this major commensal of the oral-digestive tract.
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Transcriptomic analysis of gene expression of menaquinone-7 in Bacillus subtilis natto toward different oxygen supply. Food Res Int 2020; 137:109700. [PMID: 33233274 DOI: 10.1016/j.foodres.2020.109700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/11/2020] [Accepted: 09/06/2020] [Indexed: 02/08/2023]
Abstract
Menaquinone-7 (MK-7) is an important kind of vitamin K2 which plays significant roles in the treatment of coagulation and osteoporosis, and prevention of cardiovascular disease. This work was purposed to study the differences of gene expression at different oxygen supply conditions in Bacillus natto. The differences of fermentation characteristics, gene expression related to MK-7 biosynthesis, spore and biofilm formation were analyzed. The yield of MK-7 increased by two fold under high oxygen supply condition of 200 rpm. Further transcriptome analysis indicated that most of the enzymes in MK-7 biosynthesis pathway were also up-regulated. Moreover, glycerol kinase, fructose-bisphosphate aldolase and phosphofructokinase in glycolysis pathway were all up-regulated indicating that high oxygen supply can increase the consumption of substrate glycerol. Meanwhile, menD, encoded the rate-limiting enzyme in the MK pathway, was obviously up-regulated by 3.49-fold while most of the enzymes related to spore formation were down regulated at 200 rpm. Besides, superoxide dismutase (SOD2), catalase (CAT), hydroperoxide reductase (AhpF) and DNA-binding protein MrgA in the antioxidant defense system were up-regulated, while superoxide dismutase (SOD1) and glutathione peroxidase (GSH-Px) were down-regulated. These results could contribute to a better understanding for the effect of oxygen on the MK-7 production in Bacillus natto, and further analyze the molecular regulation mechanism of MK-7 biosynthesis.
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Balderas-Ruíz KA, Bustos P, Santamaria RI, González V, Cristiano-Fajardo SA, Barrera-Ortíz S, Mezo-Villalobos M, Aranda-Ocampo S, Guevara-García ÁA, Galindo E, Serrano-Carreón L. Bacillus velezensis 83 a bacterial strain from mango phyllosphere, useful for biological control and plant growth promotion. AMB Express 2020; 10:163. [PMID: 32894363 PMCID: PMC7477031 DOI: 10.1186/s13568-020-01101-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 08/30/2020] [Indexed: 01/05/2023] Open
Abstract
Bacillus velezensis 83 was isolated from mango tree phyllosphere of orchards located in El Rosario, Sinaloa, México. The assessment of this strain as BCA (biological control agent), as well as PGPB (plant growth-promoting bacteria), were demonstrated through in vivo and in vitro assays. In vivo assays showed that B. velezensis 83 was able to control anthracnose (Kent mangoes) as efficiently as chemical treatment with Captan 50 PH™ or Cupravit hidro™. The inoculation of B. velezensis 83 to the roots of maize seedlings yielded an increase of 12% in height and 45% of root biomass, as compared with uninoculated seedlings. In vitro co-culture assays showed that B. velezensis 83 promoted Arabidopsis thaliana growth (root and shoot biomass) while, under the same experimental conditions, B. velezensis FZB42 (reference strain) had a suppressive effect on plant growth. In order to characterize the isolated strain, the complete genome sequence of B. velezensis 83 is reported. Its circular genome consists of 3,997,902 bp coding to 3949 predicted genes. The assembly and annotation of this genome revealed gene clusters related with plant-bacteria interaction and sporulation, as well as ten secondary metabolites biosynthetic gene clusters implicated in the biological control of phytopathogens. Despite the high genomic identity (> 98%) between B. velezensis 83 and B. velezensis FZB42, they are phenotypically different. Indeed, in vitro production of compounds such as surfactin and bacillomycin D (biocontrol activity) and γ-PGA (biofilm component) is significantly different between both strains. ![]()
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Huang Y, Flint SH, Palmer JS. Bacillus cereus spores and toxins – The potential role of biofilms. Food Microbiol 2020; 90:103493. [DOI: 10.1016/j.fm.2020.103493] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 01/19/2023]
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Basarab VY, Voronkova OS, Voronkova YS, Severynovska OV. The Characteristics of Growth of Bacilli Formed Fouling on Wooden Constructions. INTERNATIONAL LETTERS OF NATURAL SCIENCES 2018. [DOI: 10.56431/p-h657vz] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Problem of biofilm formation have a great significance for environmental microbiological research. Biospheric microorganisms can form biofilm, that provide bacteria resistance to influence of different environmental factors. Some of the most common bacteria in biosphere are bacilli, among them there are film-forming strains. Bacillus spp. ia a well-known film forming microorganisms that colonize environmental objects. The biofilm fouling of underwater elements of small wooden constructions located on the Dnieper River near the city of the Dnipro (Ukraine) was studied. It was found that biofilms from surfaces of water constructions include bacilli. It is established that the mean values of CFU in samples from running and still water were (1.81±0.52)×108 and (1.83±0.53)×108 CFU / ml respectively per area of wooden sample approximately 1 cm2, while during the laboratory cultivation of the film, formed by these cultures on the plate, the number of cells was (4.90±0.93)×107 and (4.60±1.07)×107 CFU / ml per 1 cm2 of the well’s bottom, which was an approximate limit of the content of cells of the Bacillus spp. film per unit of area.
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Basarab VY, Voronkova OS, Voronkova YS, Severynovska OV. The Characteristics of Growth of Bacilli Formed Fouling on Wooden Constructions. INTERNATIONAL LETTERS OF NATURAL SCIENCES 2018. [DOI: 10.18052/www.scipress.com/ilns.70.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Problem of biofilm formation have a great significance for environmental microbiological research. Biospheric microorganisms can form biofilm, that provide bacteria resistance to influence of different environmental factors. Some of the most common bacteria in biosphere are bacilli, among them there are film-forming strains.Bacillus spp.ia a well-known film forming microorganisms that colonize environmental objects. The biofilm fouling of underwater elements of small wooden constructions located on the Dnieper River near the city of the Dnipro (Ukraine) was studied. It was found that biofilms from surfaces of water constructions include bacilli. It is established that the mean values of CFU in samples from running and still water were (1.81±0.52)×108and (1.83±0.53)×108CFU / ml respectively per area of wooden sample approximately 1 cm2, while during the laboratory cultivation of the film, formed by these cultures on the plate, the number of cells was (4.90±0.93)×107and (4.60±1.07)×107CFU / ml per 1 cm2of the well’s bottom, which was an approximate limit of the content of cells of theBacillus spp.film per unit of area.
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Fan H, Zhang Z, Li Y, Zhang X, Duan Y, Wang Q. Biocontrol of Bacterial Fruit Blotch by Bacillus subtilis 9407 via Surfactin-Mediated Antibacterial Activity and Colonization. Front Microbiol 2017; 8:1973. [PMID: 29075242 PMCID: PMC5641556 DOI: 10.3389/fmicb.2017.01973] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/25/2017] [Indexed: 01/08/2023] Open
Abstract
In this study, Bacillus subtilis 9407 showed a strong antibacterial activity against Acidovorax citrulli in vitro and 61.7% biocontrol efficacy on melon seedlings 4 days post inoculation under greenhouse conditions. To understand the biocontrol mechanism of B. subtilis 9407, identify the primary antibacterial compound and determine its role in controlling bacterial fruit blotch (BFB), a srfAB deletion mutant (ΔsrfAB) was constructed. The ΔsrfAB which was deficient in production of surfactin, not only showed almost no ability to inhibit growth of A. citrulli but also decreased biofilm formation and reduced swarming motility. Colonization assay demonstrated that B. subtilis 9407 could conlonize on melon roots and leaves in a large population, while ΔsrfAB showed a four- to ten-fold reduction in colonization of melon roots and leaves. Furthermore, a biocontrol assay showed that ΔsrfAB lost the biocontrol efficacy. In summary, our results indicated that surfactin, which consists of C13- to C16-surfactin A was the primary antibacterial compound of B. subtilis 9407, and it played a major role in biofilm formation, swarming motility, colonization and suppressing BFB. We propose that the biocontrol activity of B. subtilis 9407 is the results of the coordinated action of surfactin-mediated antibacterial activity and colonization. This study reveals for the first time that the use of a B. subtilis strain as a potential biological control agent could efficiently control BFB by producing surfactin.
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Affiliation(s)
| | | | | | | | | | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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Hoffmann T, Bleisteiner M, Sappa PK, Steil L, Mäder U, Völker U, Bremer E. Synthesis of the compatible solute proline by Bacillus subtilis: point mutations rendering the osmotically controlled proHJ promoter hyperactive. Environ Microbiol 2017; 19:3700-3720. [PMID: 28752945 DOI: 10.1111/1462-2920.13870] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/09/2017] [Accepted: 07/24/2017] [Indexed: 01/29/2023]
Abstract
The ProJ and ProH enzymes of Bacillus subtilis catalyse together with ProA (ProJ-ProA-ProH), osmostress-adaptive synthesis of the compatible solute proline. The proA-encoded gamma-glutamyl phosphate reductase is also used for anabolic proline synthesis (ProB-ProA-ProI). Transcription of the proHJ operon is osmotically inducible whereas that of the proBA operon is not. Targeted and quantitative proteome analysis revealed that the amount of ProA is not limiting for the interconnected anabolic and osmostress-responsive proline production routes. A key player for enhanced osmostress-adaptive proline production is the osmotically regulated proHJ promoter. We used site-directed mutagenesis to study the salient features of this stress-responsive promoter. Two important features were identified: (i) deviations of the proHJ promoter from the consensus sequence of SigA-type promoters serve to keep transcription low under non-inducing growth conditions, while still allowing a finely tuned induction of transcriptional activity when the external osmolarity is increased and (ii) a suboptimal spacer length for SigA-type promoters of either 16-bp (the natural proHJ promoter), or 18-bp (a synthetic promoter variant) is strictly required to allow regulation of promoter activity in proportion to the external salinity. Collectively, our data suggest that changes in the local DNA structure at the proHJ promoter are important determinants for osmostress-inducibility of transcription.
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Affiliation(s)
- Tamara Hoffmann
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
| | - Monika Bleisteiner
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
| | - Praveen Kumar Sappa
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Leif Steil
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Ulrike Mäder
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Uwe Völker
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
- LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerweinstr. 6, Marburg D-35043, Germany
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Forlani G, Nocek B, Chakravarthy S, Joachimiak A. Functional Characterization of Four Putative δ 1-Pyrroline-5-Carboxylate Reductases from Bacillus subtilis. Front Microbiol 2017; 8:1442. [PMID: 28824574 PMCID: PMC5539093 DOI: 10.3389/fmicb.2017.01442] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/17/2017] [Indexed: 11/21/2022] Open
Abstract
In most living organisms, the amino acid proline is synthesized starting from both glutamate and ornithine. In prokaryotes, in the absence of an ornithine cyclodeaminase that has been identified to date only in a small number of soil and plant bacteria, these pathways share the last step, the reduction of δ1-pyrroline-5-carboxylate (P5C) catalyzed by P5C reductase (EC 1.5.1.2). In several species, multiple forms of P5C reductase have been reported, possibly reflecting the dual function of proline. Aside from its common role as a building block of proteins, proline is indeed also involved in the cellular response to osmotic and oxidative stress conditions. Genome analysis of Bacillus subtilis identifies the presence of four genes (ProH, ProI, ProG, and ComER) that, based on bioinformatic and phylogenic studies, were defined as respectively coding a putative P5C reductase. Here we describe the cloning, heterologous expression, functional analysis and small-angle X-ray scattering studies of the four affinity-purified proteins. Results showed that two of them, namely ProI and ComER, lost their catalytic efficiency or underwent subfunctionalization. In the case of ComER, this could be likely explained by the loss of the ability to form a dimer, which has been previously shown to be an essential structural feature of the catalytically active P5C reductase. The properties of the two active enzymes are consistent with a constitutive role for ProG, and suggest that ProH expression may be beneficial to satisfy an increased need for proline.
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Affiliation(s)
- Giuseppe Forlani
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
| | - Boguslaw Nocek
- Center for Structural Genomics of Infectious Diseases, University of ChicagoChicago, IL, United States
| | - Srinivas Chakravarthy
- Argonne National Laboratory, BioCAT, Center for Synchrotron Radiation Research and InstrumentationArgonne, IL, United States
- Department of Biological and Chemical Sciences, Illinois Institute of TechnologyChicago, IL, United States
| | - Andrzej Joachimiak
- Center for Structural Genomics of Infectious Diseases, University of ChicagoChicago, IL, United States
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Xu S, Yang N, Zheng S, Yan F, Jiang C, Yu Y, Guo J, Chai Y, Chen Y. The spo0A-sinI-sinR Regulatory Circuit Plays an Essential Role in Biofilm Formation, Nematicidal Activities, and Plant Protection in Bacillus cereus AR156. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:603-619. [PMID: 28430084 DOI: 10.1094/mpmi-02-17-0042-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The rhizosphere bacterium Bacillus cereus AR156 is capable of forming biofilms, killing nematodes, and protecting plants. However, the underlying molecular mechanisms of these processes are not well understood. In this study, we found that the isogenic mutants ΔBcspo0A and ΔBcsinI have significantly reduced colonization and nematicidal activity in vitro and biological control efficacy on the tomato plant under greenhouse conditions. We further investigated the role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, killing against nematodes, and biological control in AR156. Results from mutagenesis of those regulatory genes in AR156 and their heterologous expression in B. subtilis suggested that the spo0A-sinI-sinR genetic circuit is not only essential for biofilm formation and cell differentiation in AR156 but also able to functionally replace their counterparts in B. subtilis in a nearly indistinguishable fashion. Genome-wide transcriptional profiling in the wild type and the ΔBcspo0A and ΔBcsinI mutants further revealed hundreds of differentially expressed genes, likely positively regulated by both Spo0A and SinI (via SinR) in AR156. Among them, 29 genes are predicted to be directly controlled by SinR, whose counterpart in B. subtilis is a biofilm master repressor. Collectively, our studies demonstrated the essential role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, cell differentiation, and bacteria-host interactions in B. cereus AR156.
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Affiliation(s)
- Sunde Xu
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Nan Yang
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Shiyu Zheng
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Fang Yan
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chunhao Jiang
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiyang Yu
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianhua Guo
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yunrong Chai
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
| | - Yun Chen
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
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Kwon M, Hussain MS, Oh DH. Biofilm formation of Bacillus cereus under food-processing-related conditions. Food Sci Biotechnol 2017; 26:1103-1111. [PMID: 30263642 PMCID: PMC6049562 DOI: 10.1007/s10068-017-0129-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/25/2017] [Accepted: 05/02/2017] [Indexed: 12/27/2022] Open
Abstract
This study aims to understand the biofilm formation abilities of eight Bacillus cereus strains under food-industry-related conditions. Biofilms were grown in microtiter plates in tryptic soy broth (TSB) or brain heart infusion (BHI) at 30 °C for 24 or 48 h and quantified via the crystal violet assay. A significantly larger of biofilm was formed in TSB than in BHI after 48 h. Selected strains were used to test biofilm formation under food-related conditions produced by different surfaces (e.g., stainless steel, plastic, or glass), temperatures (25 or 30 °C), carbon sources, (glucose or glycerol) and NaCl. Biofilm formation appeared to be affected by surface properties, temperature, and carbon sources. A larger biofilm was formed on stainless steel at 30 °C compared to plastic and glass surfaces at 25 and 30 °C. Moreover, addition of glucose in combination with NaCl in TSB produced significantly larger biofilm than glucose, glycerol and/or NaCl. These results indicate that food-industry-related conditions could promote B. cereus biofilm formation, which is relevant to food safety.
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Affiliation(s)
- Minyeong Kwon
- Department of Food Science and Biotechnology, College of Agriculture and Life Science, Kangwon National University, Chuncheon, Gangwon 24341 Korea
| | - Mohammad Shakhawat Hussain
- Department of Food Science and Biotechnology, College of Agriculture and Life Science, Kangwon National University, Chuncheon, Gangwon 24341 Korea
| | - Deog Hwan Oh
- Department of Food Science and Biotechnology, College of Agriculture and Life Science, Kangwon National University, Chuncheon, Gangwon 24341 Korea
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30
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Genome-Wide Investigation of Biofilm Formation in Bacillus cereus. Appl Environ Microbiol 2017; 83:AEM.00561-17. [PMID: 28432092 DOI: 10.1128/aem.00561-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/12/2017] [Indexed: 01/03/2023] Open
Abstract
Bacillus cereus is a soil-dwelling Gram-positive bacterium capable of forming structured multicellular communities, or biofilms. However, the regulatory pathways controlling biofilm formation are less well understood in B. cereus In this work, we developed a method to study B. cereus biofilms formed at the air-liquid interface. We applied two genome-wide approaches, random transposon insertion mutagenesis to identify genes that are potentially important for biofilm formation, and transcriptome analyses by RNA sequencing (RNA-seq) to characterize genes that are differentially expressed in B. cereus when cells were grown in a biofilm-inducing medium. For the first approach, we identified 23 genes whose disruption by transposon insertion led to altered biofilm phenotypes. Based on the predicted function, they included genes involved in processes such as nucleotide biosynthesis, iron salvage, and antibiotic production, as well as genes encoding an ATP-dependent protease and transcription regulators. Transcriptome analyses identified about 500 genes that were differentially expressed in cells grown under biofilm-inducing conditions. One particular set of those genes may contribute to major metabolic shifts, leading to elevated production of small volatile molecules. Selected volatile molecules were shown to stimulate robust biofilm formation in B. cereus Our studies represent a genome-wide investigation of B. cereus biofilm formation.IMPORTANCE In this work, we established a robust method for B. cereus biofilm studies and applied two genome-wide approaches, transposon insertion mutagenesis and transcriptome analyses by RNA-seq, to identify genes and pathways that are potentially important for biofilm formation in B. cereus We discovered dozens of genes and two major metabolic shifts that seem to be important for biofilm formation in B. cereus Our study represents a genome-wide investigation on B. cereus biofilm formation.
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Habib C, Yu Y, Gozzi K, Ching C, Shemesh M, Chai Y. Characterization of the regulation of a plant polysaccharide utilization operon and its role in biofilm formation in Bacillus subtilis. PLoS One 2017; 12:e0179761. [PMID: 28617843 PMCID: PMC5472308 DOI: 10.1371/journal.pone.0179761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/02/2017] [Indexed: 11/18/2022] Open
Abstract
The soil bacterium Bacillus subtilis is often found in association with plants in the rhizosphere. Previously, plant polysaccharides have been shown to stimulate formation of root-associated multicellular communities, or biofilms, in this bacterium, yet the underlying mechanism is not fully understood. A five-gene gan operon (ganSPQAB) in B. subtilis has recently been shown to be involved in utilization of the plant-derived polysaccharide galactan. Despite these findings, molecular details about the regulation of the operon and the role of the operon in biofilm formation remain elusive. In this study, we performed comprehensive genetic analyses on the regulation of the gan operon. We show that this operon is regulated both by a LacI-like transcription repressor (GanR), which directly binds to pairs of inverted DNA repeats in the promoter region of the operon, and by the catabolite control protein A (CcpA). Derepression can be triggered by the presence of the inducer β-1,4-galactobiose, a hydrolysis product of galactan, or in situ when B. subtilis cells are associated with plant roots. In addition to the transcriptional regulation, the encoded ß-galactosidase GanA (by ganA), which hydrolyzes ß-1,4-galactobiose into galactose, is inhibited at the enzymatic level by the catalytic product galactose. Thus, the galactan utilization pathway is under complex regulation involving both positive and negative feedback mechanisms in B. subtilis. We discuss about the biological significance of such complex regulation as well as a hypothesis of biofilm induction by galactan via multiple mechanisms.
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Affiliation(s)
- Cameron Habib
- Department of Biology, Northeastern University, Boston, MA, United States of America
| | - Yiyang Yu
- Department of Biology, Northeastern University, Boston, MA, United States of America
| | - Kevin Gozzi
- Department of Biology, Northeastern University, Boston, MA, United States of America
| | - Carly Ching
- Department of Biology, Northeastern University, Boston, MA, United States of America
| | - Moshe Shemesh
- Agricultural Research Organization The Volcani Center, Rishon LeZion, Israel
| | - Yunrong Chai
- Department of Biology, Northeastern University, Boston, MA, United States of America
- * E-mail:
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32
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Velmourougane K, Prasanna R, Saxena AK. Agriculturally important microbial biofilms: Present status and future prospects. J Basic Microbiol 2017; 57:548-573. [PMID: 28407275 DOI: 10.1002/jobm.201700046] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/17/2017] [Accepted: 03/19/2017] [Indexed: 11/07/2022]
Abstract
Microbial biofilms are a fascinating subject, due to their significant roles in the environment, industry, and health. Advances in biochemical and molecular techniques have helped in enhancing our understanding of biofilm structure and development. In the past, research on biofilms primarily focussed on health and industrial sectors; however, lately, biofilms in agriculture are gaining attention due to their immense potential in crop production, protection, and improvement. Biofilms play an important role in colonization of surfaces - soil, roots, or shoots of plants and enable proliferation in the desired niche, besides enhancing soil fertility. Although reports are available on microbial biofilms in general; scanty information is published on biofilm formation by agriculturally important microorganisms (bacteria, fungi, bacterial-fungal) and their interactions in the ecosystem. Better understanding of agriculturally important bacterial-fungal communities and their interactions can have several implications on climate change, soil quality, plant nutrition, plant protection, bioremediation, etc. Understanding the factors and genes involved in biofilm formation will help to develop more effective strategies for sustainable and environment-friendly agriculture. The present review brings together fundamental aspects of biofilms, in relation to their formation, regulatory mechanisms, genes involved, and their application in different fields, with special emphasis on agriculturally important microbial biofilms.
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Affiliation(s)
| | - Radha Prasanna
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Anil Kumar Saxena
- ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau Nath Bhanjan, Uttar Pradesh, India
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Sadiq FA, Flint S, Li Y, Liu T, Lei Y, Sakandar HA, He G. New mechanistic insights into the motile-to-sessile switch in various bacteria with particular emphasis on Bacillus subtilis and Pseudomonas aeruginosa: a review. BIOFOULING 2017; 33:306-326. [PMID: 28347177 DOI: 10.1080/08927014.2017.1304541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/04/2017] [Indexed: 06/06/2023]
Abstract
A biofilm is a complex assemblage of microbial communities adhered to a biotic or an abiotic surface which is embedded within a self-produced matrix of extracellular polymeric substances. Many transcriptional regulators play a role in triggering a motile-sessile switch and in consequently producing the biofilm matrix. This review is aimed at highlighting the role of two nucleotide signaling molecules (c-di-GMP and c-di-AMP), toxin antitoxin modules and a novel transcriptional regulator BolA in biofilm formation in various bacteria. In addition, it highlights the common themes that have appeared in recent research regarding the key regulatory components and signal transduction pathways that help Bacillus subtilis and Pseudomonas aeruginosa to acquire the biofilm mode of life.
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Affiliation(s)
- Faizan A Sadiq
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Steve Flint
- b School of Food and Nutrition , Massey University , Palmerston North , New Zealand
| | - Yun Li
- c School of Life Sciences and Food Technology , Hanshan Normal University , Chaozhou , PR China
| | - TongJie Liu
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Yuan Lei
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | | | - GuoQing He
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
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