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Aramsangtienchai P, Kongmon T, Pechroj S, Srisook K. Enhanced production and immunomodulatory activity of levan from the acetic acid bacterium, Tanticharoenia sakaeratensis. Int J Biol Macromol 2020; 163:574-581. [PMID: 32629048 DOI: 10.1016/j.ijbiomac.2020.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 02/06/2023]
Abstract
Levan is a fructose polymer with β-(2 → 6) glycosidic linkages. It is produced by several microorganisms, and due to its potential biotechnological and industrial applications, various levan-producing bacteria with different levels of production efficiencies have been reported. We investigated the levan-producing ability of the acetic acid bacterium, Tanticharoenia sakaeratensis. The exopolysaccharides produced by the bacterium under a sucrose environment were characterized as levan by FT-IR, and 1H and 13C NMR. The molecular weight of levan thus produced range from 1.0 × 105-6.8 × 105 Da. The maximum yield of levan from T. sakaeratensis is 24.7 g·L-1 in a liquid medium containing 20% (w/v) sucrose and incubated at 37 °C, 250 RPM for 35 h. The levan produced by T. sakaeratensis can promote nitric oxide production in RAW264.7 macrophage cells in a concentration-dependent manner, suggesting it has immunomodulatory effects. Our study reveals that T. sakaeratensis can be potentially employed as a new source of levan for industrial applications.
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Affiliation(s)
- Pornpun Aramsangtienchai
- Department of Biochemistry and Research Unit of Natural Bioactive Compounds for Healthcare Products Development, Faculty of Science, Burapha University, Chonburi 20131, Thailand; Center of Excellence for Innovation in Chemistry, Burapha University, 20131, Thailand.
| | - Titapa Kongmon
- Department of Biochemistry and Research Unit of Natural Bioactive Compounds for Healthcare Products Development, Faculty of Science, Burapha University, Chonburi 20131, Thailand
| | - Sirintip Pechroj
- Department of Biochemistry and Research Unit of Natural Bioactive Compounds for Healthcare Products Development, Faculty of Science, Burapha University, Chonburi 20131, Thailand
| | - Klaokwan Srisook
- Department of Biochemistry and Research Unit of Natural Bioactive Compounds for Healthcare Products Development, Faculty of Science, Burapha University, Chonburi 20131, Thailand; Center of Excellence for Innovation in Chemistry, Burapha University, 20131, Thailand
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Okonkwo CC, Ujor V, Cornish K, Ezeji TC. Inactivation of the Levansucrase Gene in Paenibacillus polymyxa DSM 365 Diminishes Exopolysaccharide Biosynthesis during 2,3-Butanediol Fermentation. Appl Environ Microbiol 2020; 86:e00196-20. [PMID: 32144108 PMCID: PMC7170477 DOI: 10.1128/aem.00196-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/27/2020] [Indexed: 11/20/2022] Open
Abstract
The formation of exopolysaccharides (EPSs) during 2,3-butanediol (2,3-BD) fermentation by Paenibacillus polymyxa increases medium viscosity, which in turn presents considerable technical and economic challenges to 2,3-BD downstream processing. To eliminate EPS production during 2,3-BD fermentation, we used homologous recombination to disable the EPS biosynthetic pathway in P. polymyxa The gene which encodes levansucrase, the major enzyme responsible for EPS biosynthesis in P. polymyxa, was successfully disrupted. The P. polymyxa levansucrase null mutant produced 2.5 ± 0.1 and 1.2 ± 0.2 g/liter EPS on sucrose and glucose, respectively, whereas the wild type produced 21.7 ± 2.5 and 3.1 ± 0.0 g/liter EPS on the same substrates, respectively. These levels of EPS translate to 8.7- and 2.6-fold decreases in EPS formation by the levansucrase null mutant on sucrose and glucose, respectively, relative to that by the wild type, with no significant reduction in 2,3-BD production. Inactivation of EPS biosynthesis led to a considerable increase in growth. On glucose and sucrose, the cell biomass of the levansucrase null mutant (8.1 ± 0.8 and 6.5 ± 0.3 g/liter, respectively) increased 1.4-fold compared to that of the wild type (6.0 ± 0.1 and 4.6 ± 0.3 g/liter, respectively) grown on the same substrates. Evaluation of the genetic stability of the levansucrase null mutant showed that it remained genetically stable over fifty generations, with no observable decrease in growth or 2,3-BD formation, with or without antibiotic supplementation. Hence, the P. polymyxa levansucrase null mutant has potential for use as an industrial biocatalyst for a cost-effective large-scale 2,3-BD fermentation process devoid of EPS-related challenges.IMPORTANCE Given the current barrage of attention and research investments toward the production of next-generation fuels and chemicals, of which 2,3-butanediol (2,3-BD) produced by nonpathogenic Paenibacillus species is perhaps one of the most vigorously pursued, tools for engineering Paenibacillus species are intensely sought after. Exopolysaccharide (EPS) production during 2,3-BD fermentation constitutes a problem during downstream processing. Specifically, EPS negatively impacts 2,3-BD separation from the fermentation broth, thereby increasing the overall cost of 2,3-BD production. The results presented here demonstrate that inactivation of the levansucrase gene in P. polymyxa leads to diminished EPS accumulation. Additionally, a new method for an EPS assay and a simple protocol employing protoplasts for enhanced transformation of P. polymyxa were developed. Overall, although our study shows that levan is not the only EPS produced by P. polymyxa, it represents a significant first step toward developing cost-effective 2,3-BD fermentation devoid of EPS-associated complications during downstream processing.
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Affiliation(s)
- Christopher Chukwudi Okonkwo
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
| | - Victor Ujor
- Bioenergy and Water Treatment Management Program, Agricultural Technical Institute, The Ohio State University, Wooster, Ohio, USA
| | - Katrina Cornish
- Department of Food, Agricultural and Biological Engineering, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
- Department of Horticulture and Crop Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
| | - Thaddeus Chukwuemeka Ezeji
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
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Nag P, Shriti S, Das S. Microbiological strategies for enhancing biological nitrogen fixation in nonlegumes. J Appl Microbiol 2020; 129:186-198. [PMID: 31858682 DOI: 10.1111/jam.14557] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 01/17/2023]
Abstract
In an agro-ecosystem, industrially produced nitrogenous fertilizers are the principal sources of nitrogen for plant growth; unfortunately these also serve as the leading sources of pollution. Hence, it becomes imperative to find pollution-free methods of providing nitrogen to crop plants. A diverse group of free-living, plant associative and symbiotic prokaryotes are able to perform biological nitrogen fixation (BNF). BNF is a two component process involving the nitrogen fixing diazotrophs and the host plant. Symbiotic nitrogen fixation is most efficient as it can fix nitrogen inside the nodule formed on the roots of the plant; delivering nitrogen directly to the host. However, most of the important crop plants are nonleguminous and are unable to form symbiotic associations. In this context, the plant associative and endophytic diazotrophs assume importance. BNF in nonlegumes can be encouraged either through the transfer of BNF traits from legumes or by elevating the nitrogen fixing capacity of the associative and endophytic diazotrophs. In this review we discuss mainly the microbiological strategies which may be used in nonleguminous crops for enhancement of BNF.
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Affiliation(s)
- P Nag
- Division of Plant Biology, Bose Institute, Kolkata, West Bengal, India
| | - S Shriti
- Division of Plant Biology, Bose Institute, Kolkata, West Bengal, India
| | - S Das
- Division of Plant Biology, Bose Institute, Kolkata, West Bengal, India
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Jakob F, Quintero Y, Musacchio A, Estrada‐de los Santos P, Hernández L, Vogel RF. Acetic acid bacteria encode two levansucrase types of different ecological relationship. Environ Microbiol 2019; 21:4151-4165. [DOI: 10.1111/1462-2920.14768] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/24/2019] [Accepted: 07/31/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Frank Jakob
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München Gregor‐Mendel‐Straße 4, 85354 Freising Germany
| | - Yamira Quintero
- Grupo Tecnología de Enzimas, Centro de Ingeniería Genética y Biotecnología (CIGB) Ave 31 entre 158 y 190, Apartado Postal 6162, Habana 10600 Cuba
| | - Alexis Musacchio
- Departamento de Biología de Sistemas Centro de Ingeniería Genética y Biotecnología (CIGB) Ave 31 entre 158 y 190, Apartado Postal 6162, Habana 10600 Cuba
| | - Paulina Estrada‐de los Santos
- Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prol. de Carpio y Plan de Ayala s/n Col. Santo Tomás C.P., 11340 Cd. de México Mexico
| | - Lázaro Hernández
- Grupo Tecnología de Enzimas, Centro de Ingeniería Genética y Biotecnología (CIGB) Ave 31 entre 158 y 190, Apartado Postal 6162, Habana 10600 Cuba
| | - Rudi F. Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München Gregor‐Mendel‐Straße 4, 85354 Freising Germany
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Xu W, Ni D, Zhang W, Guang C, Zhang T, Mu W. Recent advances in Levansucrase and Inulosucrase: evolution, characteristics, and application. Crit Rev Food Sci Nutr 2018; 59:3630-3647. [DOI: 10.1080/10408398.2018.1506421] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Wei Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Dawei Ni
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Cuie Guang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China
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Ryngajłło M, Kubiak K, Jędrzejczak-Krzepkowska M, Jacek P, Bielecki S. Comparative genomics of the Komagataeibacter strains-Efficient bionanocellulose producers. Microbiologyopen 2018; 8:e00731. [PMID: 30365246 PMCID: PMC6528568 DOI: 10.1002/mbo3.731] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/13/2018] [Accepted: 08/21/2018] [Indexed: 12/21/2022] Open
Abstract
Komagataeibacter species are well-recognized bionanocellulose (BNC) producers. This bacterial genus, formerly assigned to Gluconacetobacter, is known for its phenotypic diversity manifested by strain-dependent carbon source preference, BNC production rate, pellicle structure, and strain stability. Here, we performed a comparative study of nineteen Komagataeibacter genomes, three of which were newly contributed in this work. We defined the core genome of the genus, clarified phylogenetic relationships among strains, and provided genetic evidence for the distinction between the two major clades, the K. xylinus and the K. hansenii. We found genomic traits, which likely contribute to the phenotypic diversity between the Komagataeibacter strains. These features include genome flexibility, carbohydrate uptake and regulation of its metabolism, exopolysaccharides synthesis, and the c-di-GMP signaling network. In addition, this work provides a comprehensive functional annotation of carbohydrate metabolism pathways, such as those related to glucose, glycerol, acetan, levan, and cellulose. Findings of this multi-genomic study expand understanding of the genetic variation within the Komagataeibacter genus and facilitate exploiting of its full potential for bionanocellulose production at the industrial scale.
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Affiliation(s)
- Małgorzata Ryngajłło
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | - Katarzyna Kubiak
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | | | - Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
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Schwab S, Terra LA, Baldani JI. Genomic characterization of Nitrospirillum amazonense strain CBAmC, a nitrogen-fixing bacterium isolated from surface-sterilized sugarcane stems. Mol Genet Genomics 2018; 293:997-1016. [PMID: 29696375 DOI: 10.1007/s00438-018-1439-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 04/18/2018] [Indexed: 02/07/2023]
Abstract
Nitrospirillum amazonense is a nitrogen-fixing bacterium that shows potential to promote plant growth when inoculated into sugarcane and rice plants. This microorganism has been the subject of biochemical and genetic characterization to elucidate important functions related to host plant interaction and growth promotion, including the determination of draft genome sequences of two strains, Y2 and CBAmC, the second of which is the aim of the present study. CBAmC has been isolated from sugarcane (Saccharum spp.), and is currently used in a sugarcane consortium inoculant with four other nitrogen-fixing bacterial strains. The present paper describes a significant improvement in the genome sequence and assembly for the N. amazonense strain CBAmC, and determination for the first time of a complete genome sequence for this bacterial species, using PacBio technology. The analysis of the genomic data obtained allowed the discovery of genes coding for metabolic pathways and cellular structures that may be determinant for the success of the bacterial establishment and colonization into the host sugarcane plant, besides conferring important characteristics to the inoculant. These include genes for the use of sucrose and N-glycans, biosynthesis of autoinducer molecules, siderophore production and acquisition, auxin and polyamine biosynthesis, flagellum, σ-fimbriae, a variety of secretion systems, and a complete denitrification system. Concerning genes for nitrogenase and auxiliary proteins, it was possible to corroborate literature data that in N. amazonense these probably had originated from horizontal gene transfer, from bacteria of the Rhizobiales order. The complete genomic sequence of the CBAmC strain of N. amazonense revealed that the bacterium harbors four replicons, including three chromosomes and one chromid, a profile that coincides with that of other two strains, according to literature data, suggesting that as a replicon pattern for the species. Finally, results of phylogenomic analyses in this work support the recent reclassification of the species, separating it from the Azospirillum genus. More importantly, results of the present work shall guide subsequent studies on strain CBAmC as well as the development of a sugarcane inoculant.
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Affiliation(s)
- Stefan Schwab
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, CNPq, Curitiba, Brazil.
- Embrapa Agrobiologia, Rodovia BR 465, km 7, Seropédica, RJ, 23891-000, Brazil.
| | - Leonardo Araujo Terra
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, CNPq, Curitiba, Brazil
- Embrapa Agrobiologia, Rodovia BR 465, km 7, Seropédica, RJ, 23891-000, Brazil
- Pró-Reitoria de Pesquisa e Pós-Graduação, Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465, km 7, Seropédica, RJ, 23890-000, Brazil
| | - José Ivo Baldani
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, CNPq, Curitiba, Brazil
- Embrapa Agrobiologia, Rodovia BR 465, km 7, Seropédica, RJ, 23891-000, Brazil
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González-Garcinuño Á, Tabernero A, Domínguez Á, Galán MA, Martin del Valle EM. Levan and levansucrases: Polymer, enzyme, micro-organisms and biomedical applications. BIOCATAL BIOTRANSFOR 2017. [DOI: 10.1080/10242422.2017.1314467] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Antonio Tabernero
- Department of Chemical Engineering, University of Salamanca, Salamanca, Spain
| | - Ángel Domínguez
- Department of Microbiology and Genetics, University of Salamanca, Salamanca, Spain
| | - Miguel A. Galán
- Department of Chemical Engineering, University of Salamanca, Salamanca, Spain
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Abstract
Type II secretion (T2S) is one means by which Gram-negative pathogens secrete proteins into the extracellular milieu and/or host organisms. Based upon recent genome sequencing, it is clear that T2S is largely restricted to the Proteobacteria, occurring in many, but not all, genera in the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria classes. Prominent human and/or animal pathogens that express a T2S system(s) include Acinetobacter baumannii, Burkholderia pseudomallei, Chlamydia trachomatis, Escherichia coli, Klebsiella pneumoniae, Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Vibrio cholerae, and Yersinia enterocolitica T2S-expressing plant pathogens include Dickeya dadantii, Erwinia amylovora, Pectobacterium carotovorum, Ralstonia solanacearum, Xanthomonas campestris, Xanthomonas oryzae, and Xylella fastidiosa T2S also occurs in nonpathogenic bacteria, facilitating symbioses, among other things. The output of a T2S system can range from only one to dozens of secreted proteins, encompassing a diverse array of toxins, degradative enzymes, and other effectors, including novel proteins. Pathogenic processes mediated by T2S include the death of host cells, degradation of tissue, suppression of innate immunity, adherence to host surfaces, biofilm formation, invasion into and growth within host cells, nutrient assimilation, and alterations in host ion flux. The reach of T2S is perhaps best illustrated by those bacteria that clearly use it for both environmental survival and virulence; e.g., L. pneumophila employs T2S for infection of amoebae, growth within lung cells, dampening of cytokines, and tissue destruction. This minireview provides an update on the types of bacteria that have T2S, the kinds of proteins that are secreted via T2S, and how T2S substrates promote infection.
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Brandt JU, Jakob F, Behr J, Geissler AJ, Vogel RF. Dissection of exopolysaccharide biosynthesis in Kozakia baliensis. Microb Cell Fact 2016; 15:170. [PMID: 27716345 PMCID: PMC5050591 DOI: 10.1186/s12934-016-0572-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/28/2016] [Indexed: 11/10/2022] Open
Abstract
Background Acetic acid bacteria (AAB) are well known producers of commercially used exopolysaccharides, such as cellulose and levan. Kozakia (K.) baliensis is a relatively new member of AAB, which produces ultra-high molecular weight levan from sucrose. Throughout cultivation of two K. baliensis strains (DSM 14400, NBRC 16680) on sucrose-deficient media, we found that both strains still produce high amounts of mucous, water-soluble substances from mannitol and glycerol as (main) carbon sources. This indicated that both Kozakia strains additionally produce new classes of so far not characterized EPS. Results By whole genome sequencing of both strains, circularized genomes could be established and typical EPS forming clusters were identified. As expected, complete ORFs coding for levansucrases could be detected in both Kozakia strains. In K. baliensis DSM 14400 plasmid encoded cellulose synthase genes and fragments of truncated levansucrase operons could be assigned in contrast to K. baliensis NBRC 16680. Additionally, both K. baliensis strains harbor identical gum-like clusters, which are related to the well characterized gum cluster coding for xanthan synthesis in Xanthomanas campestris and show highest similarity with gum-like heteropolysaccharide (HePS) clusters from other acetic acid bacteria such as Gluconacetobacter diazotrophicus and Komagataeibacter xylinus. A mutant strain of K. baliensis NBRC 16680 lacking EPS production on sucrose-deficient media exhibited a transposon insertion in front of the gumD gene of its gum-like cluster in contrast to the wildtype strain, which indicated the essential role of gumD and of the associated gum genes for production of these new EPS. The EPS secreted by K. baliensis are composed of glucose, galactose and mannose, respectively, which is in agreement with the predicted sugar monomer composition derived from in silico genome analysis of the respective gum-like clusters. Conclusions By comparative sugar monomer and genome analysis, the polymeric substances secreted by K. baliensis can be considered as unique HePS. Via genome sequencing of K. baliensis DSM 14400 + NBRC 16680 we got first insights into the biosynthesis of these novel HePS, which is related to xanthan and acetan biosynthesis. Consequently, the present study provides the basis for establishment of K. baliensis strains as novel microbial cell factories for biotechnologically relevant, unique polysaccharides. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0572-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Julia U Brandt
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Frank Jakob
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354, Freising, Germany.
| | - Jürgen Behr
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Andreas J Geissler
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Rudi F Vogel
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354, Freising, Germany
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Öner ET, Hernández L, Combie J. Review of Levan polysaccharide: From a century of past experiences to future prospects. Biotechnol Adv 2016; 34:827-844. [DOI: 10.1016/j.biotechadv.2016.05.002] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/01/2016] [Accepted: 05/04/2016] [Indexed: 01/24/2023]
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Diken E, Ozer T, Arikan M, Emrence Z, Oner ET, Ustek D, Arga KY. Genomic analysis reveals the biotechnological and industrial potential of levan producing halophilic extremophile, Halomonas smyrnensis AAD6T. SPRINGERPLUS 2015; 4:393. [PMID: 26251777 PMCID: PMC4523562 DOI: 10.1186/s40064-015-1184-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/27/2015] [Indexed: 01/21/2023]
Abstract
Halomonas smyrnensis AAD6T is a gram negative, aerobic, and moderately halophilic bacterium, and is known to produce high levels of levan with many potential uses in foods, feeds, cosmetics, pharmaceutical and chemical industries due to its outstanding properties. Here, the whole-genome analysis was performed to gain more insight about the biological mechanisms, and the whole-genome organization of the bacterium. Industrially crucial genes, including the levansucrase, were detected and the genome-scale metabolic model of H. smyrnensis AAD6T was reconstructed. The bacterium was found to have many potential applications in biotechnology not only being a levan producer, but also because of its capacity to produce Pel exopolysaccharide, polyhydroxyalkanoates, and osmoprotectants. The genomic information presented here will not only provide additional information to enhance our understanding of the genetic and metabolic network of halophilic bacteria, but also accelerate the research on systematical design of engineering strategies for biotechnology applications.
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Affiliation(s)
- Elif Diken
- />Department of Bioengineering, Marmara University, Goztepe, 34722 Istanbul, Turkey
| | - Tugba Ozer
- />Department of Bioengineering, Marmara University, Goztepe, 34722 Istanbul, Turkey
| | - Muzaffer Arikan
- />Department of Genetics, Institute for Experimental Medicine, Istanbul University, Capa, 34093 Istanbul, Turkey
| | - Zeliha Emrence
- />Department of Genetics, Institute for Experimental Medicine, Istanbul University, Capa, 34093 Istanbul, Turkey
| | - Ebru Toksoy Oner
- />Department of Bioengineering, Marmara University, Goztepe, 34722 Istanbul, Turkey
| | - Duran Ustek
- />Department of Medical Genetics, School of Medicine, REMER, Medipol University, 34810 Istanbul, Turkey
| | - Kazim Yalcin Arga
- />Department of Bioengineering, Marmara University, Goztepe, 34722 Istanbul, Turkey
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Inthanavong L, Tian F, Khodadadi M, Karboune S. Properties of Geobacillus stearothermophilus levansucrase as potential biocatalyst for the synthesis of levan and fructooligosaccharides. Biotechnol Prog 2013; 29:1405-15. [PMID: 23926090 DOI: 10.1002/btpr.1788] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/10/2013] [Indexed: 11/07/2022]
Abstract
The production of levansucrase (LS) by thermophilic Geobacillus stearothermophilus was investigated. LS production was more effective in the presence of sucrose (1%, w/v) than fructose, glucose, glycerol or raffinose. The results (Top 57°C; stable for 6 h at 47°C) indicate the high stability of the transfructosylation activity of G. stearothermophilus LS as compared with LSs from other microbial sources. Contrary to temperature, the pH had a significant effect on the selectivity of G. stearothermophilus LS-catalyzed reaction, favoring the transfructosylation reaction in the pH range of 6.0-6.5. The kinetic parameter study revealed that the catalytic efficiency of transfructosylation activity was higher as compared with the hydrolytic one. In addition to levan, G. stearothermophilus LS synthesized fructooligosaccharides in the presence of sucrose as the sole substrate. The results also demonstrated the wide acceptor specificity of G. stearothermophilus LS with maltose being the best fructosyl acceptor. This study is the first on the catalytic properties and the acceptor specificity of LS from G. stearothermophilus.
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Affiliation(s)
- Lotthida Inthanavong
- Dept. of Food Science and Agricultural Chemistry, McGill University, 21,111 Lakeshore, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada
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von Tils D, Blädel I, Schmidt MA, Heusipp G. Type II secretion in Yersinia-a secretion system for pathogenicity and environmental fitness. Front Cell Infect Microbiol 2012; 2:160. [PMID: 23248779 PMCID: PMC3521999 DOI: 10.3389/fcimb.2012.00160] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 11/29/2012] [Indexed: 11/13/2022] Open
Abstract
In Yersinia species, type III secretion (T3S) is the most prominent and best studied secretion system and a hallmark for the infection process of pathogenic Yersinia species. Type II secretion (T2S), on the other hand, is less well-characterized, although all Yersinia species, pathogenic as well as non-pathogenic, possess one or even two T2S systems. The only Yersinia strain in which T2S has so far been studied is the human pathogenic strain Y. enterocolitica 1b. Mouse infection experiments showed that at least one of the two T2S systems of Y. enterocolitica 1b, termed Yts1, is involved in dissemination and colonization of deeper tissues like liver and spleen. Interestingly, in vitro studies revealed a complex regulation of the Yts1 system, which is mainly active at low temperatures and high Mg2+-levels. Furthermore, the functional characterization of the proteins secreted in vitro indicates a role of the Yts1 machinery in survival of the bacteria in an environmental habitat. In silico analyses identified Yts1 homologous systems in bacteria that are known as plant symbionts or plant pathogens. Thus, the recent studies point to a dual function of the Yts1 T2S systems, playing a role in virulence of humans and animals, as well as in the survival of the bacteria outside of the mammalian host. In contrast, the role of the second T2S system, Yts2, remains ill defined. Whereas the T3S system and its virulence-mediating role has been intensively studied, it might now be time to also focus on the T2S system and its role in the Yersinia lifestyle, especially considering that most of the Yersinia isolates are not found in infected humans but have been gathered from various environmental samples.
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Affiliation(s)
- Dominik von Tils
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Westfälische Wilhelms-Universität Münster Münster, Germany
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Banguela A, Arrieta JG, Rodríguez R, Trujillo LE, Menéndez C, Hernández L. High levan accumulation in transgenic tobacco plants expressing the Gluconacetobacter diazotrophicus levansucrase gene. J Biotechnol 2011; 154:93-8. [PMID: 21540065 DOI: 10.1016/j.jbiotec.2011.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 04/08/2011] [Accepted: 04/13/2011] [Indexed: 11/28/2022]
Abstract
Bacterial levansucrase (EC 2.4.1.10) converts sucrose into non-linear levan consisting of long β(2,6)-linked fructosyl chains with β(2,1) branches. Bacterial levan has wide food and non-food applications, but its production in industrial reactors is costly and low yielding. Here, we report the constitutive expression of Gluconacetobacter diazotrophicus levansucrase (LsdA) fused to the vacuolar targeting pre-pro-peptide of onion sucrose:sucrose 1-fructosyltransferase (1-SST) in tobacco, a crop that does not naturally produce fructans. In the transgenic plants, levan with degree of polymerization above 10(4) fructosyl units was detected in leaves, stem, root, and flowers, but not in seeds. High levan accumulation in leaves led to gradual phenotypic alterations that increased with plant age through the flowering stage. In the transgenic lines, the fructan content in mature leaves varied from 10 to 70% of total dry weight. No oligofructans were stored in the plant organs, although the in vitro reaction of transgenic LsdA with sucrose yielded β(2,1)-linked FOS and levan. Transgenic lines with levan representing up to 30mgg(-1) of fresh leaf weight produced viable seeds and the polymer accumulation remained stable in the tested T1 and T2 progenies. The lsdA-expressing tobacco represents an alternative source of highly polymerized levan.
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Affiliation(s)
- Alexander Banguela
- Laboratorio Interacciones Planta-Microorganismo, Centro de Ingeniería Genética y Biotecnología (CIGB), Habana, Cuba.
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Gottsberger RA. Development and evaluation of a real-time PCR assay targeting chromosomal DNA of Erwinia amylovora. Lett Appl Microbiol 2010; 51:285-92. [PMID: 20666990 DOI: 10.1111/j.1472-765x.2010.02892.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To develop and evaluate a new and reliable real-time PCR detection protocol on chromosomal DNA of the contagious plant pathogenic bacterium Erwinia amylovora, the causal agent of fire blight. METHODS AND RESULTS A Taqman minor-groove-binder real-time PCR assay targeting a hypothetical protein coding gene of Erw. amylovora has been developed. Colony PCR of 113 bacterial strains from different taxa was performed to prove specificity. Serial decimal dilutions of Erw. amylovora showed a consistent detection sensitivity of 2 bacterial units per microl. All strains of Erw. amylovora could be identified, and there were no cross-reactions with matrices or other bacteria also testing naturally contaminated samples. CONCLUSIONS Rapid, reliable and sensitive detection of Erw. amylovora is important to avoid the spread of the disease within orchards, and the distribution by contaminated plant material or vectors carrying the pathogen. The selected conserved target gene allows relative quantitative detection of Erw. amylovora from different sources and host taxa. The newly developed protocol also enables the detection of recently found natural strains that lack the species-specific plasmid pEA29, which was so far widely used as target for detection and identification of this plant pathogen by PCR. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrates that the newly developed and evaluated real-time assay can specifically be used for identifying all known strains of the EU quarantine plant pathogen Erw. amylovora. Low concentrations of the bacteria can be detected and relatively quantified using a different target area than other real-time PCRs designed so far.
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Affiliation(s)
- R A Gottsberger
- Austrian Agency for Health and Food Safety (AGES), Institute of Plant Health, Vienna, Austria.
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Palmieri ACB, do Amaral AM, Homem RA, Machado MA. Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress. Genet Mol Biol 2010; 33:348-53. [PMID: 21637493 PMCID: PMC3036875 DOI: 10.1590/s1415-47572010005000030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 10/14/2009] [Indexed: 11/21/2022] Open
Abstract
In this study, we used real-time quantitative PCR (RT-qPCR) to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC) and two involved in the degradation of plant cell wall components (pglA and pel) were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon) and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases.
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Bertalan M, Albano R, de Pádua V, Rouws L, Rojas C, Hemerly A, Teixeira K, Schwab S, Araujo J, Oliveira A, França L, Magalhães V, Alquéres S, Cardoso A, Almeida W, Loureiro MM, Nogueira E, Cidade D, Oliveira D, Simão T, Macedo J, Valadão A, Dreschsel M, Freitas F, Vidal M, Guedes H, Rodrigues E, Meneses C, Brioso P, Pozzer L, Figueiredo D, Montano H, Junior J, de Souza Filho G, Martin Quintana Flores V, Ferreira B, Branco A, Gonzalez P, Guillobel H, Lemos M, Seibel L, Macedo J, Alves-Ferreira M, Sachetto-Martins G, Coelho A, Santos E, Amaral G, Neves A, Pacheco AB, Carvalho D, Lery L, Bisch P, Rössle SC, Urményi T, Rael Pereira A, Silva R, Rondinelli E, von Krüger W, Martins O, Baldani JI, Ferreira PCG. Complete genome sequence of the sugarcane nitrogen-fixing endophyte Gluconacetobacter diazotrophicus Pal5. BMC Genomics 2009; 10:450. [PMID: 19775431 PMCID: PMC2765452 DOI: 10.1186/1471-2164-10-450] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 09/23/2009] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins. RESULTS Gluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified, and was most likely acquired by horizontal gene transfer. This portion of the genome has likely contributed to adaptation to the plant habitat. CONCLUSION The genome data offer an important resource of information that can be used to manipulate plant/bacterium interactions with the aim of improving sugarcane crop production and other biotechnological applications.
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Affiliation(s)
- Marcelo Bertalan
- Instituto de Bioquímica Médica, UFRJ, CCS, Bloco D, subssolo 21491-590 Rio de Janeiro, Brazil.
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Velázquez-Hernández M, Baizabal-Aguirre V, Bravo-Patiño A, Cajero-Juárez M, Chávez-Moctezuma M, Valdez-Alarcón J. Microbial fructosyltransferases and the role of fructans. J Appl Microbiol 2009; 106:1763-78. [DOI: 10.1111/j.1365-2672.2008.04120.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Transcriptional regulation and signal-peptide-dependent secretion of exolevanase (LsdB) in the endophyte Gluconacetobacter diazotrophicus. Appl Environ Microbiol 2009; 75:1782-5. [PMID: 19139238 DOI: 10.1128/aem.01887-08] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gluconacetobacter diazotrophicus utilizes plant sucrose with a constitutively expressed levansucrase (LsdA), producing extracellular levan, which may be degraded under energetically unfavored conditions. Reverse transcriptase-PCR analysis revealed that lsdA and the downstream exolevanase gene (lsdB) form an operon. lsdB transcription was induced during growth with low fructose concentrations (0.44 to 33 mM) and repressed by glucose. Transport of LsdB to the periplasm involved N-terminal signal peptide cleavage. Type II secretion mutants failed to transfer LsdB across the outer membrane, impeding levan hydrolysis.
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Goldman D, Lavid N, Schwartz A, Shoham G, Danino D, Shoham Y. Two Active Forms of Zymomonas mobilis Levansucrase. J Biol Chem 2008; 283:32209-17. [DOI: 10.1074/jbc.m805985200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Lery LMS, Coelho A, von Kruger WMA, Gonçalves MSM, Santos MF, Valente RH, Santos EO, Rocha SLG, Perales J, Domont GB, Teixeira KRS, Bertalan M, Ferreira PCG, Bisch PM. Protein expression profile of Gluconacetobacter diazotrophicus PAL5, a sugarcane endophytic plant growth-promoting bacterium. Proteomics 2008; 8:1631-44. [PMID: 18340630 DOI: 10.1002/pmic.200700912] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This is the first broad proteomic description of Gluconacetobacter diazotrophicus, an endophytic bacterium, responsible for the major fraction of the atmospheric nitrogen fixed in sugarcane in tropical regions. Proteomic coverage of G. diazotrophicus PAL5 was obtained by two independent approaches: 2-DE followed by MALDI-TOF or TOF-TOF MS and 1-DE followed by chromatography in a C18 column online coupled to an ESI-Q-TOF or ESI-IT mass spectrometer. The 583 identified proteins were sorted into functional categories and used to describe potential metabolic pathways for nucleotides, amino acids, carbohydrates, lipids, cofactors and energy production, according to the Enzyme Commission of Enzyme Nomenclature (EC) and Kyoto Encyclopedia of genes and genomes (KEGG) databases. The identification of such proteins and their possible insertion in conserved biochemical routes will allow comparisons between G. diazotrophicus and other bacterial species. Furthermore, the 88 proteins classified as conserved unknown or unknown constitute a potential target for functional genomic studies, aiming at the understanding of protein function and regulation of gene expression. The knowledge of metabolic fundamentals and coordination of these actions are crucial for the rational, safe and sustainable interference on crops. The entire dataset, including peptide sequence information, is available as Supporting Information and is the major contribution of this work.
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Pedraza RO. Recent advances in nitrogen-fixing acetic acid bacteria. Int J Food Microbiol 2007; 125:25-35. [PMID: 18177965 DOI: 10.1016/j.ijfoodmicro.2007.11.079] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 10/10/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
Abstract
Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects, as well as their association with different plants and contribution through BNF are described as an overview.
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Affiliation(s)
- Raúl O Pedraza
- Departamento de Ecología, Microbiología Agrícola. Facultad de Agronomía y Zootecnia, Universidad Nacional de Tucumán. Av. Roca 1900, (4000) Tucumán, Argentina.
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Mehta T, Childers SE, Glaven R, Lovley DR, Mester T. A putative multicopper protein secreted by an atypical type II secretion system involved in the reduction of insoluble electron acceptors in Geobacter sulfurreducens. Microbiology (Reading) 2006; 152:2257-2264. [PMID: 16849792 DOI: 10.1099/mic.0.28864-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extracellular electron transfer onto Fe(III) oxides in Geobacter sulfurreducens is considered to require proteins that must be exported to the outer surface of the cell. In order to investigate this, the putative gene for OxpG, the pseudopilin involved in a type II general secretion pathway of Gram-negative bacteria, was deleted. The mutant was unable to grow with insoluble Fe(III) oxide as the electron acceptor. Growth on soluble Fe(III) was not affected. An analysis of proteins that accumulated in the periplasm of the oxpG mutant, but not in the wild-type, led to the identification of a secreted protein, OmpB. OmpB is predicted to be a multicopper protein, with highest homology to the manganese oxidase, MofA, from Leptothrix discophora. OmpB contains a potential Fe(III)-binding site and a fibronectin type III domain, suggesting a possible role for this protein in accessing Fe(III) oxides. OmpB was localized to the membrane fraction of G. sulfurreducens and in the supernatant of growing cultures, consistent with the type II secretion system exporting OmpB. A mutant in which ompB was deleted had the same phenotype as the oxpG mutant, suggesting that the failure to export OmpB was responsible for the inability of the oxpG-deficient mutant to reduce Fe(III) oxide. This is the first report that proposes a role for a multicopper oxidase-like protein in an anaerobic organism. These results further emphasize the importance of outer-membrane proteins in Fe(III) oxide reduction and suggest that outer-membrane proteins other than c-type cytochromes are required for Fe(III) oxide reduction in Geobacter species.
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Affiliation(s)
- Teena Mehta
- Department of Microbiology, Morrill IV North, University of Massachusetts, Amherst, MA 01003, USA
| | - Susan E Childers
- Department of Microbiology, Morrill IV North, University of Massachusetts, Amherst, MA 01003, USA
| | - Richard Glaven
- Department of Microbiology, Morrill IV North, University of Massachusetts, Amherst, MA 01003, USA
| | - Derek R Lovley
- Department of Microbiology, Morrill IV North, University of Massachusetts, Amherst, MA 01003, USA
| | - Tünde Mester
- Department of Microbiology, Morrill IV North, University of Massachusetts, Amherst, MA 01003, USA
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Zhao Y, Blumer SE, Sundin GW. Identification of Erwinia amylovora genes induced during infection of immature pear tissue. J Bacteriol 2005; 187:8088-103. [PMID: 16291682 PMCID: PMC1291285 DOI: 10.1128/jb.187.23.8088-8103.2005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Accepted: 09/16/2005] [Indexed: 02/02/2023] Open
Abstract
The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes and separated them into nine putative function groups including host-microbe interactions (3.8%), stress response (5.3%), regulation (11.9%), cell surface (8.9%), transport (13.5%), mobile elements (1.0%), metabolism (20.3%), nutrient acquisition and synthesis (15.5%), and unknown or hypothetical proteins (19.8%). Known virulence genes, including hrp/hrc components of the type III secretion system, the major effector gene dspE, type II secretion, levansucrase (lsc), and regulators of levansucrase and amylovoran biosynthesis, were upregulated during pear tissue infection. Known virulence factors previously identified in E. (Pectobacterium) carotovora and Pseudomonas syringae were identified for the first time in E. amylovora and included HecA hemagglutinin family adhesion, Peh polygalacturonase, new effector HopPtoC(EA), and membrane-bound lytic murein transglycosylase MltE(EA). An insertional mutation within hopPtoC(EA) did not result in reduced virulence; however, an mltE(EA) knockout mutant was reduced in virulence and growth in immature pears. This study suggests that E. amylovora utilizes a variety of strategies during plant infection and to overcome the stressful and poor nutritional environment of its plant hosts.
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Affiliation(s)
- Youfu Zhao
- Department of Plant Pathology, Michigan State University, East Lansing, 48824, USA
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Cianciotto NP. Type II secretion: a protein secretion system for all seasons. Trends Microbiol 2005; 13:581-8. [PMID: 16216510 DOI: 10.1016/j.tim.2005.09.005] [Citation(s) in RCA: 258] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 09/06/2005] [Accepted: 09/22/2005] [Indexed: 01/20/2023]
Abstract
In Gram-negative bacteria, type II secretion (T2S) is one of five protein secretion systems that permit the export of proteins from within the bacterial cell to the extracellular milieu and/or into target host cells. An analysis of numerous sequenced genomes now reveals that T2S genes are common, but by no means universal, in Gram-negative bacteria. Recent functional studies indicate that T2S can promote the virulence of human, animal and plant pathogens, as well as the physiology of various environmental bacteria. Thus, it is an opportune time to highlight the new and different ways in which T2S serves bacterial function.
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Affiliation(s)
- Nicholas P Cianciotto
- Department of Microbiology-Immunology, Northwestern University Medical School, Chicago, IL 60611, USA.
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