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Delaunay L, Postollec F, Leguérinel I, Mathot AG. Detection of risk areas in dairy powder processes: The development of thermophilic spore forming bacteria taking into account their growth limits. Int J Food Microbiol 2024; 418:110716. [PMID: 38669747 DOI: 10.1016/j.ijfoodmicro.2024.110716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 04/16/2024] [Accepted: 04/21/2024] [Indexed: 04/28/2024]
Abstract
Anoxybacillus flavithermus, Geobacillus stearothermophilus and Bacillus licheniformis are the main contaminants found in dairy powders. These spore-forming thermophilic bacteria, rarely detected in raw milk, persist, and grow during the milk powder manufacturing process. Moreover, in the form of spores, these species resist and concentrate in the powders during the processes. The aim of this study was to determine the stages of the dairy powder manufacturing processes that are favorable to the growth of such contaminants. A total of 5 strains were selected for each species as a natural contaminant of dairy pipelines in order to determine the minimum and maximum growth enabling values for temperature, pH, and aw and their optimum growth rates in milk. These growth limits were combined with the environmental conditions of temperature, pH and aw encountered at each step of the manufacture of whole milk, skim milk and milk protein concentrate powders to estimate growth capacities using cardinal models and the Gamma concept. These simulations were used to theoretically calculate the population sizes reached for the different strains studied at each stage in between two successive cleaning in place procedures. This approach highlights the stages at which risk occurs for the development of spore-forming thermophilic bacterial species. During the first stages of production, i.e. pre-treatment, pasteurization, standardization and pre-heating before concentration, physico-chemical conditions encountered are suitable for the development and growth of A. flavithermus, G. stearothermophilus and B. licheniformis. During the pre-heating stage and during the first effects in the evaporators, the temperature conditions appear to be the most favorable for the growth of G. stearothermophilus. The temperatures in the evaporator during the last evaporator effects are favorable for the growth of B. licheniformis. In the evaporation stage, low water activity severely limits the development of A. flavithermus.
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Affiliation(s)
- Louis Delaunay
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, 29000 Quimper, France
| | - Florence Postollec
- ADRIA Food Technology Institute, UMT ACTIA 19.03 ALTER'iX, Z.A. de Creac'h Gwen, 29196, Quimper, Cedex, France
| | - Ivan Leguérinel
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, 29000 Quimper, France.
| | - Anne-Gabrielle Mathot
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, 29000 Quimper, France
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2
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El Zowalaty ME, Falgenhauer L, Ashour HM, Zishiri OT, Forsythe S, Helmy YA. Draft genome sequences of Bacillus licheniformis strains MEZBL63 and MEZBL64 harboring the lichenysin toxin operon isolated from livestock in South Africa. Microbiol Resour Announc 2024; 13:e0096723. [PMID: 38323846 DOI: 10.1128/mra.00967-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/05/2024] [Indexed: 02/08/2024] Open
Abstract
Here, we report the draft genome sequences of two Bacillus licheniformis strains harboring the lichenysin operon that were isolated from healthy goat and horse in South Africa. The genomes were sequenced using Illumina MiSeq and had a length of 4,152,826 and 4,110,075 bp, respectively, with a G + C content of 46%.
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Affiliation(s)
- Mohamed E El Zowalaty
- Veterinary Medicine and Food Security Research Group, Medical Laboratory Sciences Program, Faculty of Health Sciences, Abu Dhabi Women's Campus, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates
| | - Linda Falgenhauer
- Institute of Hygiene and Environmental Medicine, German Center for Infection Research, Site Giessen-Marburg-Langen and Hessian University Competence Center for Hospital Hygiene (HuKKH), Justus Liebig University Giessen, Giessen, Germany
| | - Hossam M Ashour
- Department of Integrative Biology, College of Arts and Sciences, University of South Florida, St. Petersburg, Florida, USA
| | - Oliver T Zishiri
- Discipline of Genetics, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Durban, South Africa
| | - Stephen Forsythe
- Foodmicrobe.com Ltd, Adams Hill, Keyworth, Nottingham, United Kingdom
| | - Yosra A Helmy
- Department of Veterinary Science, Martin-Gatton College of Agriculture, Food, and Environment, University of Kentucky, Lexington, Kentucky, USA
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3
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Kiraz D, Özcan A, Yibar A, Dertli E. Genetic diversity and phylogenetic relationships of Streptococcus thermophilus isolates from traditional Turkish yogurt: multilocus sequence typing (MLST). Arch Microbiol 2024; 206:121. [PMID: 38400998 DOI: 10.1007/s00203-024-03850-7] [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: 11/29/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 02/26/2024]
Abstract
Yogurt, a globally consumed fermented dairy product, is recognized for its taste and potential health benefits attributed to probiotic bacteria, particularly Streptococcus thermophilus. In this study, we employed Multilocus Sequence Typing (MLST) to investigate the genetic diversity and phylogenetic relationships of 13 S. thermophilus isolates from traditional Turkish yogurt samples. We also assessed potential correlations between genetic traits and geographic origins. The isolates were identified as S. thermophilus using VITEK® MALDI-TOF MS, ribotyping, and 16S rRNA analysis methods. MLST analysis revealed 13 different sequence types (STs), with seven new STs for Turkey. The most prevalent STs were ST/83 (n = 3), ST/135 (n = 2), and ST/134 (n = 2). eBURST analysis showed that these isolates mainly were singletons (n = 7) defined as sequence types (STs) that cannot be assigned to any group and differ at two or more alleles from every other ST in the sample. This information suggests that the isolates under study were genetically distinct from the other isolates in the dataset, highlighting their unique genetic profiles within the population. Genetic diversity analysis of ten housekeeping genes revealed polymorphism, with some genes showing higher allelic variation than others. Tajima's D values suggested that selection pressures differed among these genes, with some being more conserved, likely due to their vital functions. Phylogenetic analysis revealed distinct genetic diversity between Turkish isolates and European and Asian counterparts. These findings demonstrate the genetic diversity of S. thermophilus isolates in Turkish yogurt and highlight their unique evolutionary patterns. This research contributes to our understanding of local microbial diversity associated with yogurt production in Turkey and holds the potential for identifyic strains with enhanced functional attributes.
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Affiliation(s)
- Deniz Kiraz
- Animal Originated Foodstuffs Department, Central Research Institute of Food and Feed Control, Bursa, Turkey.
| | - Ali Özcan
- Animal Originated Foodstuffs Department, Central Research Institute of Food and Feed Control, Bursa, Turkey
- Food Hygiene and Technology Department, Faculty of Veterinary Medicine, Uludağ University, Bursa, Turkey
| | - Artun Yibar
- Food Hygiene and Technology Department, Faculty of Veterinary Medicine, Uludağ University, Bursa, Turkey
| | - Enes Dertli
- Faculty of Chemistry and Metallurgy, Department of Food Engineering, Yildiz Technical University, Istanbul, Turkey
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4
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Ngom SI, Maski S, Rached B, Chouati T, Oliveira Correia L, Juste C, Meylheuc T, Henrissat B, El Fahime E, Amar M, Béra-Maillet C. Exploring the hemicellulolytic properties and safety of Bacillus paralicheniformis as stepping stone in the use of new fibrolytic beneficial microbes. Sci Rep 2023; 13:22785. [PMID: 38129471 PMCID: PMC10740013 DOI: 10.1038/s41598-023-49724-8] [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: 01/20/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Bacillus strains from the Moroccan Coordinated Collections of Microorganisms (CCMM) were characterised and tested for fibrolytic function and safety properties that would be beneficial for maintaining intestinal homeostasis, and recommend beneficial microbes in the field of health promotion research. Forty strains were investigated for their fibrolytic activities towards complex purified polysaccharides and natural fibres representative of dietary fibres (DFs) entering the colon for digestion. We demonstrated hemicellulolytic activities for nine strains of Bacillus aerius, re-identified as Bacillus paralicheniformis and Bacillus licheniformis, using xylan, xyloglucan or lichenan as purified polysaccharides, and orange, apple and carrot natural fibres, with strain- and substrate-dependent production of glycoside hydrolases (GHs). Our combined methods, based on enzymatic assays, secretome, and genome analyses, highlighted the hemicellulolytic activities of B. paralicheniformis and the secretion of specific glycoside hydrolases, in particular xylanases, compared to B. licheniformis. Genomic features of these strains revealed a complete set of GH genes dedicated to the degradation of various polysaccharides from DFs, including cellulose, hemicellulose and pectin, which may confer on the strains the ability to digest a variety of DFs. Preliminary experiments on the safety and immunomodulatory properties of B. paralicheniformis fibrolytic strains were evaluated in light of applications as beneficial microbes' candidates for health improvement. B. paralicheniformis CCMM B969 was therefore proposed as a new fibrolytic beneficial microbe candidate.
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Affiliation(s)
- Serigne Inssa Ngom
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Soufiane Maski
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Département de Biologie, Faculté des Sciences, Université Mohammed V, Rabat, Morocco
| | - Bahia Rached
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Laboratoire de Chimie-Physique et Biotechnologies des Biomolécules et Matériaux/Equipe Microbiologie Biomolécules et Biotechnologies, Faculté des Sciences et Techniques, Mohammedia, Morocco
| | - Taha Chouati
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Biologie médicale, Pathologie humaine et Expérimentale et Environnement, Faculté de Médecine et de pharmacie de Rabat, Rabat, Morocco
| | - Lydie Oliveira Correia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, PAPPSO, 78350, Jouy-en-Josas, France
| | - Catherine Juste
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Thierry Meylheuc
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, MIMA2, 78350, Jouy en Josas, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, 13288, Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Elmostafa El Fahime
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Biologie médicale, Pathologie humaine et Expérimentale et Environnement, Faculté de Médecine et de pharmacie de Rabat, Rabat, Morocco
| | - Mohamed Amar
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
| | - Christel Béra-Maillet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France.
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco.
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MLST analysis of genetic diversity of Bacillus coagulans strains to evaluate effects on constipation model. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2022.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Hemicellulosic biomass conversion by Moroccan hot spring Bacillus paralicheniformis CCMM B940 evidenced by glycoside hydrolase activities and whole genome sequencing. 3 Biotech 2021; 11:379. [PMID: 34447652 PMCID: PMC8298745 DOI: 10.1007/s13205-021-02919-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022] Open
Abstract
Thermophilic bacteria, especially from the genus Bacillus, constitute a huge potential source of novel enzymes that could be relevant for biotechnological applications. In this work, we described the cellulose and hemicellulose-related enzymatic activities of the hot spring Bacillus aerius CCMM B940 from the Moroccan Coordinated Collections of Microorganisms (CCMM), and revealed its potential for hemicellulosic biomass utilization. Indeed, B940 was able to degrade complex polysaccharides such as xylan and lichenan and exhibited activity towards carboxymethylcellulose. The strain was also able to grow on agriculture waste such as orange and apple peels as the sole carbon source. Whole-genome sequencing allowed the reclassification of CCMM B940 previously known as B. aerius into Bacillus paralicheniformis since the former species name has been rejected. The draft genome reported here is composed of 38 contigs resulting in a genome of 4,315,004 bp and an average G + C content of 45.87%, and is an important resource for illuminating the molecular mechanisms of carbohydrate metabolism. The annotated genomic sequences evidenced more than 52 genes encoding glycoside hydrolases and pectate lyases belonging to 27 different families of CAZymes that are involved in the degradation of plant cell wall carbohydrates. Genomic predictions in addition to in vitro experiments have revealed broad hydrolytic capabilities of the strain, thus reinforcing its relevance for biotechnology applications.
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Muras A, Romero M, Mayer C, Otero A. Biotechnological applications of Bacillus licheniformis. Crit Rev Biotechnol 2021; 41:609-627. [PMID: 33593221 DOI: 10.1080/07388551.2021.1873239] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacillus licheniformis is a Gram positive spore-forming bacterial species of high biotechnological interest with numerous present and potential uses, including the production of bioactive compounds that are applied in a wide range of fields, such as aquaculture, agriculture, food, biomedicine, and pharmaceutical industries. Its use as an expression vector for the production of enzymes and other bioproducts is also gaining interest due to the availability of novel genetic manipulation tools. Furthermore, besides its widespread use as a probiotic, other biotechnological applications of B. licheniformis strains include: bioflocculation, biomineralization, biofuel production, bioremediation, and anti-biofilm activity. Although authorities have approved the use of B. licheniformis as a feed additive worldwide due to the absence of toxigenic potential, some probiotics containing this bacterium are considered unsafe due to the possible transference of antibiotic resistance genes. The wide variability in biological activities and genetic characteristics of this species makes it necessary to establish an exact protocol for describing the novel strains, in order to evaluate its biotechnological potential.
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Affiliation(s)
- Andrea Muras
- Departmento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Manuel Romero
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Celia Mayer
- Departmento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ana Otero
- Departmento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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8
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Classifying the Unclassified: A Phage Classification Method. Viruses 2019; 11:v11020195. [PMID: 30813498 PMCID: PMC6409715 DOI: 10.3390/v11020195] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/06/2019] [Accepted: 02/20/2019] [Indexed: 01/21/2023] Open
Abstract
This work reports the method ClassiPhage to classify phage genomes using sequence derived taxonomic features. ClassiPhage uses a set of phage specific Hidden Markov Models (HMMs) generated from clusters of related proteins. The method was validated on all publicly available genomes of phages that are known to infect Vibrionaceae. The phages belong to the well-described phage families of Myoviridae, Podoviridae, Siphoviridae, and Inoviridae. The achieved classification is consistent with the assignments of the International Committee on Taxonomy of Viruses (ICTV), all tested phages were assigned to the corresponding group of the ICTV-database. In addition, 44 out of 58 genomes of Vibrio phages not yet classified could be assigned to a phage family. The remaining 14 genomes may represent phages of new families or subfamilies. Comparative genomics indicates that the ability of the approach to identify and classify phages is correlated to the conserved genomic organization. ClassiPhage classifies phages exclusively based on genome sequence data and can be applied on distinct phage genomes as well as on prophage regions within host genomes. Possible applications include (a) classifying phages from assembled metagenomes; and (b) the identification and classification of integrated prophages and the splitting of phage families into subfamilies.
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9
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Agersø Y, Bjerre K, Brockmann E, Johansen E, Nielsen B, Siezen R, Stuer-Lauridsen B, Wels M, Zeidan AA. Putative antibiotic resistance genes present in extant Bacillus licheniformis and Bacillus paralicheniformis strains are probably intrinsic and part of the ancient resistome. PLoS One 2019; 14:e0210363. [PMID: 30645638 PMCID: PMC6333372 DOI: 10.1371/journal.pone.0210363] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/20/2018] [Indexed: 12/13/2022] Open
Abstract
Whole-genome sequencing and phenotypic testing of 104 strains of Bacillus licheniformis and Bacillus paralicheniformis from a variety of sources and time periods was used to characterize the genetic background and evolution of (putative) antimicrobial resistance mechanisms. Core proteins were identified in draft genomes and a phylogenetic analysis based on single amino acid polymorphisms allowed the species to be separated into two phylogenetically distinct clades with one outlier. Putative antimicrobial resistance genes were identified and mapped. A chromosomal ermD gene was found at the same location in all B. paralichenformis and in 27% of B. licheniformis genomes. Erythromycin resistance correlated very well with the presence of ermD. The putative streptomycin resistance genes, aph and aadK, were found in the chromosome of all strains as adjacent loci. Variations in amino acid sequence did not correlate with streptomycin susceptibility although the species were less susceptible than other Bacillus species. A putative chloramphenicol resistance gene (cat), encoding a novel chloramphenicol acetyltransferase protein was also found in the chromosome of all strains. Strains encoding a truncated CAT protein were sensitive to chloramphenicol. For all four resistance genes, the diversity and genetic context followed the overall phylogenetic relationship. No potentially mobile genetic elements were detected in their vicinity. Moreover, the genes were only distantly related to previously-described cat, aph, aad and erm genes present on mobile genetic elements or in other species. Thus, these genes are suggested to be intrinsic to B. licheniformis and B. paralicheniformis and part of their ancient resistomes. Since there is no evidence supporting horizontal transmission, these genes are not expected to add to the pool of antibiotic resistance elements considered to pose a risk to human or animal health. Whole-genome based phylogenetic and sequence analysis, combined with phenotypic testing, is proposed to be suitable for determining intrinsic resistance and evolutionary relationships.
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Annapurna K, Govindasamy V, Sharma M, Ghosh A, Chikara SK. Whole genome shotgun sequence of Bacillus paralicheniformis strain KMS 80, a rhizobacterial endophyte isolated from rice ( Oryza sativa L.). 3 Biotech 2018; 8:223. [PMID: 29692960 DOI: 10.1007/s13205-018-1242-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 04/03/2018] [Indexed: 11/26/2022] Open
Abstract
Bacillus paralicheniformis strain KMS 80 (MTCC No. 12704) is an isolate from the root tissues of rice (Oryza sativa L.) that displays biological nitrogen fixation and plant growth promoting abilities. Here, we report the complete genome sequence of this strain, which contains 4,566,040 bp, 4424 protein-coding genes, 8692 promoter sequences, 67 tRNAs, 20 rRNA genes with six copies of 5S rRNAs along with a single copy of 16S-23S rRNA and genome average GC-content of 45.50%. Twenty one genes involved in nitrogen metabolism pathway and two main transcriptional factor genes, glnR and tnrA responsible for regulation of nitrogen fixation in Bacillus sp. were predicted from the whole genome of strain KMS 80. Analysis of the ~ 4.57 Mb genome sequence will give support to understand the genetic determinants of host range, endophytic colonization behaviour as well as to enhance endophytic nitrogen fixation and other plant beneficial role of B. paralicheniformis in rice.
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Affiliation(s)
- Kannepalli Annapurna
- 1Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Venkadasamy Govindasamy
- 1Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Meenakshi Sharma
- 1Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Arpita Ghosh
- Eurofins Genomics India Private Limited, Bangalore, 560048 Karnataka India
| | - Surendra K Chikara
- Eurofins Genomics India Private Limited, Bangalore, 560048 Karnataka India
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11
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Rapid screening of starter cultures for maari based on antifungal properties. Microbiol Res 2018; 207:66-74. [DOI: 10.1016/j.micres.2017.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 08/17/2017] [Accepted: 11/07/2017] [Indexed: 11/20/2022]
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12
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Almeida E, Serra CR, Albuquerque P, Guerreiro I, Teles AO, Enes P, Tavares F. Multiplex PCR identification and culture-independent quantification of Bacillus licheniformis by qPCR using specific DNA markers. Food Microbiol 2018; 74:1-10. [PMID: 29706322 DOI: 10.1016/j.fm.2018.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 12/29/2017] [Accepted: 02/17/2018] [Indexed: 11/26/2022]
Abstract
Probiotics benefits in fish farming have been usually inferred appraising the effects observed on the host and not through the direct assessment of probiotic dynamics in the host gut microbiota. To overcome this gap, quantitative PCR (qPCR) can be a powerful approach to study the bacterial dynamics in fish gut microbiota. The presented work proposes four B. licheniformis-specific DNA markers and details a qPCR method to track putative probiotics B. licheniformis on fish gut. The four B. licheniformis-specific DNA markers - BL5B (hypothetical protein BL00303), BL8A (serA2), BL13C (rfaB) and BL18A (ligD) - were selected and validated by PCR and multiplex-PCR with 20 B. licheniformis isolates and a broad range of non-target bacteria. To assess the dynamics of B. licheniformis in the digesta of farmed fish, a qPCR was validated using markers BL8A and BL18A and calibration curves obtained for both markers with digesta samples spiked with B. licheniformis cells showed a high correlation (R2 > 0.99) over 6 log units (CFU/reaction), and a limit of detection (LOD) as low as 247 CFUs/reaction. Furthermore, the consistent qPCR repeatability and reproducibility underline the specificity and reliability of the qPCR proposed. Ultimately, the possibility to monitor the dynamics of B. licheniformis probiotics in the gut microbiota of farmed fish might be instrumental to optimize best practices in aquaculture.
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Affiliation(s)
- Eduarda Almeida
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal; FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal
| | - Cláudia R Serra
- CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Pedro Albuquerque
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Inês Guerreiro
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Aires Oliva Teles
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Paula Enes
- CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Fernando Tavares
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal; FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal.
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13
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Lee C, Kim JY, Song HS, Kim YB, Choi YE, Yoon C, Nam YD, Roh SW. Genomic Analysis of Bacillus licheniformis CBA7126 Isolated from a Human Fecal Sample. Front Pharmacol 2017; 8:724. [PMID: 29081747 PMCID: PMC5645497 DOI: 10.3389/fphar.2017.00724] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/25/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Changsu Lee
- Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, South Korea
| | - Joon Yong Kim
- Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, South Korea
| | - Hye Seon Song
- Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, South Korea
| | - Yeon Bee Kim
- Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, South Korea
| | - Yoon-E Choi
- Division of Environmental Science & Ecological Engineering, Korea University, Seoul, South Korea
| | - Changmann Yoon
- Division of Environmental Science & Ecological Engineering, Korea University, Seoul, South Korea
| | - Young-Do Nam
- Research Group of Gut Microbiome, Korea Food Research Institute, Sungnam, South Korea.,Department of Food Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Seong Woon Roh
- Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, South Korea
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Borch-Pedersen K, Mellegård H, Reineke K, Boysen P, Sevenich R, Lindbäck T, Aspholm M. Effects of High Pressure on Bacillus licheniformis Spore Germination and Inactivation. Appl Environ Microbiol 2017; 83:e00503-17. [PMID: 28476768 PMCID: PMC5494625 DOI: 10.1128/aem.00503-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/01/2017] [Indexed: 11/20/2022] Open
Abstract
Bacillus and Clostridium species form spores, which pose a challenge to the food industry due to their ubiquitous nature and extreme resistance. Pressurization at <300 MPa triggers spore germination by activating germination receptors (GRs), while pressurization at >300 MPa likely triggers germination by opening dipicolinic acid (DPA) channels present in the inner membrane of the spores. In this work, we expose spores of Bacillus licheniformis, a species associated with food spoilage and occasionally with food poisoning, to high pressure (HP) for holding times of up to 2 h. By using mutant spores lacking one or several GRs, we dissect the roles of the GerA, Ynd, and GerK GRs in moderately HP (mHP; 150 MPa)-induced spore germination. We show that Ynd alone is sufficient for efficient mHP-induced spore germination. GerK also triggers germination with mHP, although at a reduced germination rate compared to that of Ynd. GerA stimulates mHP-induced germination but only in the presence of either the intact GerK or Ynd GR. These results suggests that the effectiveness of the individual GRs in mHP-induced germination differs from their effectiveness in nutrient-induced germination, where GerA plays an essential role. In contrast to Bacillus subtilis spores, treatment with very HP (vHP) of 550 MPa at 37°C did not promote effective germination of B. licheniformis spores. However, treatment with vHP in combination with elevated temperatures (60°C) gave a synergistic effect on spore germination and inactivation. Together, these results provide novel insights into how HP affects B. licheniformis spore germination and inactivation and the role of individual GRs in this process.IMPORTANCE Bacterial spores are inherently resistant to food-processing regimes, such as high-temperature short-time pasteurization, and may therefore compromise food durability and safety. The induction of spore germination facilitates subsequent inactivation by gentler processing conditions that maintain the sensory and nutritional qualities of the food. High-pressure (HP) processing is a nonthermal food-processing technology used to eliminate microbes from food. The application of this technology for spore eradication in the food industry requires a better understanding of how HP affects the spores of different bacterial species. The present study provides novel insights into how HP affects Bacillus licheniformis spores, a species associated with food spoilage and occasionally food poisoning. We describe the roles of different germination receptors in HP-induced germination and the effects of two different pressure levels on the germination and inactivation of spores. This study will potentially contribute to the effort to implement HP technology for spore inactivation in the food industry.
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Affiliation(s)
- Kristina Borch-Pedersen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, the Norwegian University of Life Sciences, Oslo, Norway
| | - Hilde Mellegård
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, the Norwegian University of Life Sciences, Oslo, Norway
| | - Kai Reineke
- Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, Germany
| | - Preben Boysen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, the Norwegian University of Life Sciences, Oslo, Norway
| | - Robert Sevenich
- Department of Food Biotechnology and Food Process Engineering, Technische Universität Berlin, Berlin, Germany
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, the Norwegian University of Life Sciences, Oslo, Norway
| | - Marina Aspholm
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, the Norwegian University of Life Sciences, Oslo, Norway
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15
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Dunlap CA, Kwon SW, Rooney AP, Kim SJ. Bacillus paralicheniformis sp. nov., isolated from fermented soybean paste. Int J Syst Evol Microbiol 2015; 65:3487-3492. [PMID: 26296568 DOI: 10.1099/ijsem.0.000441] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
An isolate of a Gram-stain-positive, facultatively anaerobic, motile, rod-shaped, endospore-forming bacterium was recovered from soybean-based fermented paste. Phylogenetic analysis of the 16S rRNA gene indicated that the strain was most closely related to Bacillus sonorensis KCTC-13918T (99.5 % similarity) and Bacillus licheniformis DSM 13T (99.4 %). In phenotypic characterization, the novel strain was found to grow at 15–60 °C and to tolerate up to 10 % (w/v) NaCl. Furthermore, the strain grew in media with pH 6–11 (optimal growth at pH 7.0–8.0). The predominant cellular fatty acids were anteiso-C15 : 0 (37.7 %) and iso-C15 : 0 (31.5 %). The predominant isoprenoid quinone was menaquinone 7 (MK-7). The cell-wall peptidoglycan contained meso-diaminopimelic acid. A draft genome sequence of the strain was completed and used for phylogenetic analysis. Phylogenomic analysis of all published genomes of species in the B. licheniformis group revealed that strains belonging to B. licheniformis clustered into two distinct groups, with group 1 consisting of B. licheniformis DSM 13T and 11 other strains and group 2 consisting of KJ-16T and four other strains. The DNA G+C content of strain KJ-16T was 45.9 % (determined from the genome sequence). Strain KJ-16T and another strain from group 2 were subsequently characterized using a polyphasic taxonomic approach and compared with strains from group 1 and another closely related species of the genus Bacillus. Based upon the consensus of phylogenetic and phenotypic analyses, we conclude that this strain represents a novel species within the genus Bacillus, for which the name Bacillus paralicheniformis sp. nov. is proposed, with type strain KJ-16T ( = KACC 18426T = NRRL B-65293T).
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Affiliation(s)
- Christopher A Dunlap
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, IL, USA
| | - Soon-Wo Kwon
- Korean Agriculture Culture Collection (KACC), Agricultural Microbiology Division, National Academy of Agricultural Science, Rural Development Administration, Wanju-gun, Jeollabuk-do, Republic of Korea
| | - Alejandro P Rooney
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, IL, USA
| | - Soo-Jin Kim
- Korean Agriculture Culture Collection (KACC), Agricultural Microbiology Division, National Academy of Agricultural Science, Rural Development Administration, Wanju-gun, Jeollabuk-do, Republic of Korea
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, IL, USA
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16
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Dan T, Liu W, Song Y, Xu H, Menghe B, Zhang H, Sun Z. The evolution and population structure of Lactobacillus fermentum from different naturally fermented products as determined by multilocus sequence typing (MLST). BMC Microbiol 2015; 15:107. [PMID: 25990318 PMCID: PMC4437502 DOI: 10.1186/s12866-015-0447-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/14/2015] [Indexed: 11/11/2022] Open
Abstract
Background Lactobacillus fermentum is economically important in the production and preservation of fermented foods. A repeatable and discriminative typing method was devised to characterize L. fermentum at the molecular level. The multilocus sequence typing (MLST) scheme developed was based on analysis of the internal sequence of 11 housekeeping gene fragments (clpX, dnaA, dnaK, groEL, murC, murE, pepX, pyrG, recA, rpoB, and uvrC). Results MLST analysis of 203 isolates of L. fermentum from Mongolia and seven provinces/ autonomous regions in China identified 57 sequence types (ST), 27 of which were represented by only a single isolate, indicating high genetic diversity. Phylogenetic analyses based on the sequence of the 11 housekeeping gene fragments indicated that the L. fermentum isolates analyzed belonged to two major groups. A standardized index of association (IAS) indicated a weak clonal population structure in L. fermentum. Split decomposition analysis indicated that recombination played an important role in generating the genetic diversity observed in L. fermentum. The results from the minimum spanning tree strongly suggested that evolution of L. fermentum STs was not correlated with geography or food-type. Conclusions The MLST scheme developed will be valuable for further studies on the evolution and population structure of L. fermentum isolates used in food products. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0447-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tong Dan
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Wenjun Liu
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Yuqin Song
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Haiyan Xu
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Bilige Menghe
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
| | - Zhihong Sun
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
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17
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Vithanage NR, Yeager TR, Jadhav SR, Palombo EA, Datta N. Comparison of identification systems for psychrotrophic bacteria isolated from raw bovine milk. Int J Food Microbiol 2014; 189:26-38. [DOI: 10.1016/j.ijfoodmicro.2014.07.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 07/17/2014] [Accepted: 07/20/2014] [Indexed: 10/25/2022]
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18
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Dan T, Liu W, Sun Z, Lv Q, Xu H, Song Y, Zhang H. A novel multi-locus sequence typing (MLST) protocol for Leuconostoc lactis isolates from traditional dairy products in China and Mongolia. BMC Microbiol 2014; 14:150. [PMID: 24912963 PMCID: PMC4063691 DOI: 10.1186/1471-2180-14-150] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/04/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Economically, Leuconostoc lactis is one of the most important species in the genus Leuconostoc. It plays an important role in the food industry including the production of dextrans and bacteriocins. Currently, traditional molecular typing approaches for characterisation of this species at the isolate level are either unavailable or are not sufficiently reliable for practical use. Multilocus sequence typing (MLST) is a robust and reliable method for characterising bacterial and fungal species at the molecular level. In this study, a novel MLST protocol was developed for 50 L. lactis isolates from Mongolia and China. RESULTS Sequences from eight targeted genes (groEL, carB, recA, pheS, murC, pyrG, rpoB and uvrC) were obtained. Sequence analysis indicated 20 different sequence types (STs), with 13 of them being represented by a single isolate. Phylogenetic analysis based on the sequences of eight MLST loci indicated that the isolates belonged to two major groups, A (34 isolates) and B (16 isolates). Linkage disequilibrium analyses indicated that recombination occurred at a low frequency in L. lactis, indicating a clonal population structure. Split-decomposition analysis indicated that intraspecies recombination played a role in generating genotypic diversity amongst isolates. CONCLUSIONS Our results indicated that MLST is a valuable tool for typing L. lactis isolates that can be used for further monitoring of evolutionary changes and population genetics.
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Affiliation(s)
| | | | | | | | | | | | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P, R, China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, P, R, China.
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19
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Pandey A, Dhakar K, Sharma A, Priti P, Sati P, Kumar B. Thermophilic bacteria that tolerate a wide temperature and pH range colonize the Soldhar (95 °C) and Ringigad (80 °C) hot springs of Uttarakhand, India. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0921-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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20
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Madslien EH, Granum PE, Blatny JM, Lindbäck T. L-alanine-induced germination in Bacillus licheniformis -the impact of native gerA sequences. BMC Microbiol 2014; 14:101. [PMID: 24755193 PMCID: PMC4021175 DOI: 10.1186/1471-2180-14-101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND L-alanine, acting through the GerA receptor, was recently found to be an efficient germinant in Bacillus licheniformis ATCC14580/DSM13. RESULTS In this study, we show that several of 46 examined B. licheniformis strains germinate remarkably slower than the type strain when exposed to L-alanine. These strains are not necessarily closely related, as determined by MLST (multi-locus sequence typing). Three of the slow-germinating strains were further examined in order to see whether nucleotide substitutions in the gerA sequences were responsible for the slow L-alanine germination. This was performed by complementing the transformable type strain derivate MW3ΔgerAA with gerA variants from the three slow-germinating strains; NVH1032, NVH1112 and NVH800. CONCLUSIONS A wide selection of B. licheniformis strains was evaluated for L-alanine-induced germination efficiency. Our results show that gerA substitutions could only partially explain why spores of some B. licheniformis strains responded slower than others in the presence of L-alanine.
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Affiliation(s)
| | | | | | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P, O, Box 8146 Dep, N-0033 Oslo, Norway.
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21
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Draft genome comparison of representatives of the three dominant genotype groups of dairy Bacillus licheniformis strains. Appl Environ Microbiol 2014; 80:3453-62. [PMID: 24657871 DOI: 10.1128/aem.00065-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The spore-forming bacterium Bacillus licheniformis is a common contaminant of milk and milk products. Strains of this species isolated from dairy products can be differentiated into three major groups, namely, G, F1, and F2, using random amplification of polymorphic DNA (RAPD) analysis; however, little is known about the genomic differences between these groups and the identity of the fragments that make up their RAPD profiles. In this work we obtained high-quality draft genomes of representative strains from each of the three RAPD groups (designated strain G-1, strain F1-1, and strain F2-1) and compared them to each other and to B. licheniformis ATCC 14580 and Bacillus subtilis 168. Whole-genome comparison and multilocus sequence typing revealed that strain G-1 contains significant sequence variability and belongs to a lineage distinct from the group F strains. Strain G-1 was found to contain genes coding for a type I restriction modification system, urease production, and bacitracin synthesis, as well as the 8-kbp plasmid pFL7, and these genes were not present in strains F1-1 and F2-1. In agreement with this, all isolates of group G, but no group F isolates, were found to possess urease activity and antimicrobial activity against Micrococcus. Identification of RAPD band sequences revealed that differences in the RAPD profiles were due to differences in gene lengths, 3' ends of predicted primer binding sites, or gene presence or absence. This work provides a greater understanding of the phylogenetic and phenotypic differences observed within the B. licheniformis species.
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Madslien EH, Rønning HT, Lindbäck T, Hassel B, Andersson MA, Granum PE. Lichenysin is produced by most Bacillus licheniformis strains. J Appl Microbiol 2013; 115:1068-80. [PMID: 23844764 DOI: 10.1111/jam.12299] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 11/28/2022]
Abstract
AIMS The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. METHODS AND RESULTS Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. CONCLUSIONS Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml(-1) , which is in accordance with previous studies. SIGNIFICANCE AND IMPACT OF STUDY This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive.
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Affiliation(s)
- E H Madslien
- Forsvarets Forskningsinstitutt FFI, Norwegian Defence Research Establishment, Kjeller, Norway; Department of Food Safety and Infection Biology, Section for Food Safety, Norwegian School of Veterinary Science, Oslo, Norway
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