51
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Veliz EA, Martínez-Hidalgo P, Hirsch AM. Chitinase-producing bacteria and their role in biocontrol. AIMS Microbiol 2017; 3:689-705. [PMID: 31294182 PMCID: PMC6604996 DOI: 10.3934/microbiol.2017.3.689] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/19/2017] [Indexed: 11/30/2022] Open
Abstract
Chitin is an important component of the exteriors of insects and fungi. Upon degradation of chitin by a number of organisms, severe damage and even death may occur in pathogens and pests whose external surfaces contain this polymer. Currently, chemical fungicides and insecticides are the major means of controlling these disease-causing agents. However, due to the potential harm that these chemicals cause to the environment and to human and animal health, new strategies are being developed to replace or reduce the use of fungal- and pest-killing compounds in agriculture. In this context, chitinolytic microorganisms are likely to play an important role as biocontrol agents and pathogen antagonists and may also function in the control of postharvest rot. In this review, we discuss the literature concerning chitin and the basic knowledge of chitin-degrading enzymes, and also describe the biocontrol effects of chitinolytic microorganisms and their potential use as more sustainable pesticides and fungicides in the field.
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Affiliation(s)
- Esteban A Veliz
- Department of Molecular Cell and Developmental Biology, Molecular Biology Institute, University of California, Los Angeles, 90095-1606, USA
| | | | - Ann M Hirsch
- Department of Molecular Cell and Developmental Biology, Molecular Biology Institute, University of California, Los Angeles, 90095-1606, USA
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52
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Lasica AM, Ksiazek M, Madej M, Potempa J. The Type IX Secretion System (T9SS): Highlights and Recent Insights into Its Structure and Function. Front Cell Infect Microbiol 2017. [PMID: 28603700 DOI: 10.3389/fcimb.2017.00215.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein secretion systems are vital for prokaryotic life, as they enable bacteria to acquire nutrients, communicate with other species, defend against biological and chemical agents, and facilitate disease through the delivery of virulence factors. In this review, we will focus on the recently discovered type IX secretion system (T9SS), a complex translocon found only in some species of the Bacteroidetes phylum. T9SS plays two roles, depending on the lifestyle of the bacteria. It provides either a means of movement (called gliding motility) for peace-loving environmental bacteria or a weapon for pathogens. The best-studied members of these two groups are Flavobacterium johnsoniae, a commensal microorganism often found in water and soil, and Porphyromonas gingivalis, a human oral pathogen that is a major causative agent of periodontitis. In P. gingivalis and some other periodontopathogens, T9SS translocates proteins, especially virulence factors, across the outer membrane (OM). Proteins destined for secretion bear a conserved C-terminal domain (CTD) that directs the cargo to the OM translocon. At least 18 proteins are involved in this still enigmatic process, with some engaged in the post-translational modification of T9SS cargo proteins. Upon translocation across the OM, the CTD is removed by a protease with sortase-like activity and an anionic LPS is attached to the newly formed C-terminus. As a result, a cargo protein could be secreted into the extracellular milieu or covalently attached to the bacterial surface. T9SS is regulated by a two-component system; however, the precise environmental signal that triggers it has not been identified. Exploring unknown systems contributing to bacterial virulence is exciting, as it may eventually lead to new therapeutic strategies. During the past decade, the major components of T9SS were identified, as well as hints suggesting the possible mechanism of action. In addition, the list of characterized cargo proteins is constantly growing. The actual structure of the translocon, situated in the OM of bacteria, remains the least explored area; however, new technical approaches and increasing scientific attention have resulted in a growing body of data. Therefore, we present a compact up-to-date review of this topic.
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Affiliation(s)
- Anna M Lasica
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Bacterial Genetics, Faculty of Biology, Institute of Microbiology, University of WarsawWarsaw, Poland
| | - Miroslaw Ksiazek
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
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53
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Biancalana F, Kopprio GA, Lara RJ, Alonso C. A protocol for the simultaneous identification of chitin-containing particles and their associated bacteria. Syst Appl Microbiol 2017. [PMID: 28648723 DOI: 10.1016/j.syapm.2017.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Chitin is the second most abundant polymer on Earth, playing a crucial role in the biogeochemical cycles. A core issue for studying its processing in aquatic systems is the identification and enumeration of chitin-containing particles and organisms, ideally in a manner that can be directly linked to bulk chitin quantification. The aim of this study was the development of such a technique. We successfully combined the methodology of bulk chitin determination using wheat germ agglutinin (FITC-WGA) for staining chitin-containing particles and organisms along with CARD-FISH staining of either chitin-containing eukaryotic cells or bacteria associated with them. Environmental chitin staining was successfully applied to natural water samples. Fungal hyphae, diatoms, and dinoflagellates, sestonic aggregates and chitin-containing structures derived from metazoa were observed. Also, hybridized bacteria attached to chitinaceous debris were clearly visualized. Finally, as proof of principle, cultured yeast cells were simultaneously-targeted by FITC-WGA and the EUK516 probe without exhibiting any interference between both stains. The presented approach appears as a powerful tool to evaluate the contribution of different size classes and organisms to chitin production and consumption, opening the possibility for application of single-cell approaches targeting the ecophysiology of chitin transformations in aquatic systems.
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Affiliation(s)
- Florencia Biancalana
- Instituto Argentino de Oceanografía, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, Florida 4750, B8000FWB Bahía Blanca, Argentina.
| | - Germán A Kopprio
- Instituto Argentino de Oceanografía, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, Florida 4750, B8000FWB Bahía Blanca, Argentina; Leibniz Center for Tropical Marine Ecology (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany
| | - Rubén J Lara
- Instituto Argentino de Oceanografía, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, Florida 4750, B8000FWB Bahía Blanca, Argentina
| | - Cecilia Alonso
- Microbial Ecology of Aquatic Transitional Systems Research Group, Centro Universitario Región Este, Universidad de la República, Ruta nacional N°9, 2700 Rocha, Uruguay
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54
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Lasica AM, Ksiazek M, Madej M, Potempa J. The Type IX Secretion System (T9SS): Highlights and Recent Insights into Its Structure and Function. Front Cell Infect Microbiol 2017; 7:215. [PMID: 28603700 PMCID: PMC5445135 DOI: 10.3389/fcimb.2017.00215] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/11/2017] [Indexed: 12/11/2022] Open
Abstract
Protein secretion systems are vital for prokaryotic life, as they enable bacteria to acquire nutrients, communicate with other species, defend against biological and chemical agents, and facilitate disease through the delivery of virulence factors. In this review, we will focus on the recently discovered type IX secretion system (T9SS), a complex translocon found only in some species of the Bacteroidetes phylum. T9SS plays two roles, depending on the lifestyle of the bacteria. It provides either a means of movement (called gliding motility) for peace-loving environmental bacteria or a weapon for pathogens. The best-studied members of these two groups are Flavobacterium johnsoniae, a commensal microorganism often found in water and soil, and Porphyromonas gingivalis, a human oral pathogen that is a major causative agent of periodontitis. In P. gingivalis and some other periodontopathogens, T9SS translocates proteins, especially virulence factors, across the outer membrane (OM). Proteins destined for secretion bear a conserved C-terminal domain (CTD) that directs the cargo to the OM translocon. At least 18 proteins are involved in this still enigmatic process, with some engaged in the post-translational modification of T9SS cargo proteins. Upon translocation across the OM, the CTD is removed by a protease with sortase-like activity and an anionic LPS is attached to the newly formed C-terminus. As a result, a cargo protein could be secreted into the extracellular milieu or covalently attached to the bacterial surface. T9SS is regulated by a two-component system; however, the precise environmental signal that triggers it has not been identified. Exploring unknown systems contributing to bacterial virulence is exciting, as it may eventually lead to new therapeutic strategies. During the past decade, the major components of T9SS were identified, as well as hints suggesting the possible mechanism of action. In addition, the list of characterized cargo proteins is constantly growing. The actual structure of the translocon, situated in the OM of bacteria, remains the least explored area; however, new technical approaches and increasing scientific attention have resulted in a growing body of data. Therefore, we present a compact up-to-date review of this topic.
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Affiliation(s)
- Anna M Lasica
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Bacterial Genetics, Faculty of Biology, Institute of Microbiology, University of WarsawWarsaw, Poland
| | - Miroslaw Ksiazek
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
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55
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Diverse C-Terminal Sequences Involved in Flavobacterium johnsoniae Protein Secretion. J Bacteriol 2017; 199:JB.00884-16. [PMID: 28396348 DOI: 10.1128/jb.00884-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/24/2017] [Indexed: 12/26/2022] Open
Abstract
Flavobacteriumjohnsoniae and many related bacteria secrete proteins across the outer membrane using the type IX secretion system (T9SS). Proteins secreted by T9SSs have amino-terminal signal peptides for export across the cytoplasmic membrane by the Sec system and carboxy-terminal domains (CTDs) targeting them for secretion across the outer membrane by the T9SS. Most but not all T9SS CTDs belong to the family TIGR04183 (type A CTDs). We functionally characterized diverse CTDs for secretion by the F. johnsoniae T9SS. Attachment of the CTDs from F. johnsoniae RemA, AmyB, and ChiA to the foreign superfolder green fluorescent protein (sfGFP) that had a signal peptide at the amino terminus resulted in secretion across the outer membrane. In each case, approximately 80 to 100 amino acids from the extreme carboxy termini were needed for efficient secretion. Several type A CTDs from distantly related members of the phylum Bacteroidetes functioned in F. johnsoniae, supporting the secretion of sfGFP by the F. johnsoniae T9SS. F. johnsoniae SprB requires the T9SS for secretion but lacks a type A CTD. It has a conserved C-terminal domain belonging to the family TIGR04131, which we refer to as a type B CTD. The CTD of SprB was required for its secretion, but attachment of C-terminal regions of SprB of up to 1,182 amino acids to sfGFP failed to result in secretion. Additional features outside the C-terminal region of SprB may be required for its secretion.IMPORTANCE Type IX protein secretion systems (T9SSs) are common in but limited to members of the phylum Bacteroidetes Most proteins that are secreted by T9SSs have conserved carboxy-terminal domains that belong to the protein domain family TIGR04183 (type A CTDs) or TIGR04131 (type B CTDs). Here, we identify features of T9SS CTDs of F. johnsoniae that are required for protein secretion and demonstrate that type A CTDs from distantly related members of the phylum function with the F. johnsoniae T9SS to secrete the foreign protein sfGFP. In contrast, type B CTDs failed to target sfGFP for secretion, suggesting a more complex association with the T9SS.
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56
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Revised domain structure of ulvan lyase and characterization of the first ulvan binding domain. Sci Rep 2017; 7:44115. [PMID: 28327560 PMCID: PMC5361163 DOI: 10.1038/srep44115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 02/06/2017] [Indexed: 01/02/2023] Open
Abstract
Biomass waste products from green algae have recently been given new life, as these polysaccharides have potential applications in industry, agriculture, and medicine. One such polysaccharide group called ulvans displays many different, potentially useful properties that arise from their structural versatility. Hence, performing structural analyses on ulvan is crucial for future applications. However, chemical reaction–based analysis methods cannot fully characterize ulvan and tend to alter its structure. Thus, better methods require well-characterized ulvan-degrading enzymes. Therefore, we analysed a previously sequenced ulvan lyase (GenebankTM reference number JN104480) and characterized its domains. We suggest that the enzyme consists of a shorter than previously described catalytic domain, a newly identified substrate binding domain, and a C-terminal type 9 secretion system signal peptide. By separately expressing the two domains in E. coli, we confirmed that the binding domain is ulvan specific, having higher affinity for ulvan than most lectins for their ligands (affinity constant: 105 M−1). To our knowledge, this is the first description of an ulvan-binding domain. Overall, identifying this new binding domain is one step towards engineering ulvan enzymes that can be used to characterize ulvan, e.g. through enzymatic/mass spectrometric fingerprinting analyses, and help unlock its full potential.
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57
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Larsbrink J, Tuveng TR, Pope PB, Bulone V, Eijsink VG, Brumer H, McKee LS. Proteomic insights into mannan degradation and protein secretion by the forest floor bacterium Chitinophaga pinensis. J Proteomics 2017; 156:63-74. [DOI: 10.1016/j.jprot.2017.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/13/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
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58
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Wissuwa J, Bauer SLM, Steen IH, Stokke R. Complete genome sequence of Lutibacter profundi LP1 T isolated from an Arctic deep-sea hydrothermal vent system. Stand Genomic Sci 2017; 12:5. [PMID: 28078050 PMCID: PMC5219744 DOI: 10.1186/s40793-016-0219-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/07/2016] [Indexed: 11/10/2022] Open
Abstract
Lutibacter profundi LP1T within the family Flavobacteriaceae was isolated from a biofilm growing on the surface of a black smoker chimney at the Loki's Castle vent field, located on the Arctic Mid-Ocean Ridge. The complete genome of L. profundi LP1T is the first genome to be published within the genus Lutibacter. L. profundi LP1T consists of a single 2,966,978 bp circular chromosome with a GC content of 29.8%. The genome comprises 2,537 protein-coding genes, 40 tRNA species and 2 rRNA operons. The microaerophilic, organotrophic isolate contains genes for all central carbohydrate metabolic pathways. However, genes for the oxidative branch of the pentose-phosphate-pathway, the glyoxylate shunt of the tricarboxylic acid cycle and the ATP citrate lyase for reverse TCA are not present. L. profundi LP1T utilizes starch, sucrose and diverse proteinous carbon sources. In accordance, the genome harbours 130 proteases and 104 carbohydrate-active enzymes, indicating a specialization in degrading organic matter. Among a small arsenal of 24 glycosyl hydrolases, which offer the possibility to hydrolyse diverse poly- and oligosaccharides, a starch utilization cluster was identified. Furthermore, a variety of enzymes may be secreted via T9SS and contribute to the hydrolytic variety of the microorganism. Genes for gliding motility are present, which may enable the bacteria to move within the biofilm. A substantial number of genes encoding for extracellular polysaccharide synthesis pathways, curli fibres and attachment to surfaces could mediate adhesion in the biofilm and may contribute to the biofilm formation. In addition to aerobic respiration, the complete denitrification pathway and genes for sulphide oxidation e.g. sulphide:quinone reductase are present in the genome. sulphide:quinone reductase and denitrification may serve as detoxification systems allowing L. profundi LP1T to thrive in a sulphide and nitrate enriched environment. The information gained from the genome gives a greater insight in the functional role of L. profundi LP1T in the biofilm and its adaption strategy in an extreme environment.
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Affiliation(s)
- Juliane Wissuwa
- Centre for Geobiology, University of Bergen, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
| | - Sven Le Moine Bauer
- Centre for Geobiology, University of Bergen, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
| | - Ida Helene Steen
- Centre for Geobiology, University of Bergen, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
| | - Runar Stokke
- Centre for Geobiology, University of Bergen, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
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59
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Lupatini M, Korthals GW, de Hollander M, Janssens TKS, Kuramae EE. Soil Microbiome Is More Heterogeneous in Organic Than in Conventional Farming System. Front Microbiol 2017; 7:2064. [PMID: 28101080 PMCID: PMC5209367 DOI: 10.3389/fmicb.2016.02064] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/07/2016] [Indexed: 11/17/2022] Open
Abstract
Organic farming system and sustainable management of soil pathogens aim at reducing the use of agricultural chemicals in order to improve ecosystem health. Despite the essential role of microbial communities in agro-ecosystems, we still have limited understanding of the complex response of microbial diversity and composition to organic and conventional farming systems and to alternative methods for controlling plant pathogens. In this study we assessed the microbial community structure, diversity and richness using 16S rRNA gene next generation sequences and report that conventional and organic farming systems had major influence on soil microbial diversity and community composition while the effects of the soil health treatments (sustainable alternatives for chemical control) in both farming systems were of smaller magnitude. Organically managed system increased taxonomic and phylogenetic richness, diversity and heterogeneity of the soil microbiota when compared with conventional farming system. The composition of microbial communities, but not the diversity nor heterogeneity, were altered by soil health treatments. Soil health treatments exhibited an overrepresentation of specific microbial taxa which are known to be involved in soil suppressiveness to pathogens (plant-parasitic nematodes and soil-borne fungi). Our results provide a comprehensive survey on the response of microbial communities to different agricultural systems and to soil treatments for controlling plant pathogens and give novel insights to improve the sustainability of agro-ecosystems by means of beneficial microorganisms.
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Affiliation(s)
- Manoeli Lupatini
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Gerard W. Korthals
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Mattias de Hollander
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Thierry K. S. Janssens
- MicroLife SolutionsAmsterdam, Netherlands
- Department of Ecological Science, Vrije Universiteit AmsterdamAmsterdam, Netherlands
| | - Eiko E. Kuramae
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
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60
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Nakayama K. [The type IX secretion system and the type V pilus in the phylum Bacteroidetes]. Nihon Saikingaku Zasshi 2017; 72:219-227. [PMID: 29109335 DOI: 10.3412/jsb.72.219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many bacteria symbiotic and parasitic in humans are included in the genera Bacteroides, Prevotella, Porphyromonas and others, which belong to the phylum Bacteroidetes. We have been studying gingipain, a major secretory protease of Porphyromonas gingivalis which is a periodontopathogenic bacterium belonging to the genus Porphyromonas, and pili which contribute to host colonization in the bacterium. In the process, it was found that gingipain was secreted by a system not reported previously. Furthermore, this secretion system was found to exist widely in the Bacteroidetes phylum bacteria and closely related to the gliding motility of bacteroidete bacteria, and it was named the Por secretion system (later renamed the type IX secretion system). Regarding P. gingivalis pili, it was found that the pilus protein is transported as a lipoprotein to the cell surface, and the pilus formation occurs due to degradation by arginine-gingipain. Pili with this novel formation mechanism was found to be widely present in bacteria belonging to the class Bacteroidia in the phylum Bacteroidetes and was named the type V pili.
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Affiliation(s)
- Koji Nakayama
- Department of Microbiology and Oral Infection, Nagasaki University Graduate School of Biomedical Sciences
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61
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DiLoreto ZA, Weber PA, Olds W, Pope J, Trumm D, Chaganti SR, Heath DD, Weisener CG. Novel cost effective full scale mussel shell bioreactors for metal removal and acid neutralization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 183:601-612. [PMID: 27633144 DOI: 10.1016/j.jenvman.2016.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/01/2016] [Accepted: 09/04/2016] [Indexed: 06/06/2023]
Abstract
Acid mine drainage (AMD) impacted waters are a worldwide concern for the mining industry and countries dealing with this issue; both active and passive technologies are employed for the treatment of such waters. Mussel shell bioreactors (MSB) represent a passive technology that utilizes waste from the shellfish industry as a novel substrate. The aim of this study is to provide insight into the biogeochemical dynamics of a novel full scale MSB for AMD treatment. A combination of water quality data, targeted geochemical extractions, and metagenomic analyses were used to evaluate MSB performance. The MSB raised the effluent pH from 3.4 to 8.3 while removing up to ∼99% of the dissolved Al, and Fe and >90% Ni, Tl, and Zn. A geochemical gradient was observed progressing from oxidized to reduced conditions with depth. The redox conditions helped define the microbial consortium that consists of a specialized niche of organisms that influence elemental cycling (i.e. complex Fe and S cycling). MSB technology represents an economic and effective means of full scale, passive AMD treatment that is an attractive alternative for developing economies due to its low cost and ease of implementation.
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Affiliation(s)
- Z A DiLoreto
- University of Windsor, Great Lakes Institute for Environmental Research (GLIER), 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - P A Weber
- O'Kane Consultants (NZ) Ltd, Unit 2, 2 McMillan Street, Darfield, New Zealand
| | - W Olds
- O'Kane Consultants (NZ) Ltd, Unit 2, 2 McMillan Street, Darfield, New Zealand
| | - J Pope
- CRL Energy Ltd, 97 Nazareth Avenue, Christchurch, New Zealand
| | - D Trumm
- CRL Energy Ltd, 97 Nazareth Avenue, Christchurch, New Zealand
| | - S R Chaganti
- University of Windsor, Great Lakes Institute for Environmental Research (GLIER), 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - D D Heath
- University of Windsor, Great Lakes Institute for Environmental Research (GLIER), 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - C G Weisener
- University of Windsor, Great Lakes Institute for Environmental Research (GLIER), 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada.
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Vaikuntapu PR, Rambabu S, Madhuprakash J, Podile AR. A new chitinase-D from a plant growth promoting Serratia marcescens GPS5 for enzymatic conversion of chitin. BIORESOURCE TECHNOLOGY 2016; 220:200-207. [PMID: 27567481 DOI: 10.1016/j.biortech.2016.08.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 08/05/2016] [Accepted: 08/06/2016] [Indexed: 06/06/2023]
Abstract
The current study describes heterologous expression and biochemical characterization of single-modular chitinase-D from Serratia marcescens (SmChiD) with unprecedented catalytic properties which include chitobiase and transglycosylation (TG) activities besides hydrolytic activity. Without accessory domains, SmChiD, hydrolyzed insoluble polymeric chitin substrates like colloidal, α- and β-chitin. Activity studies on CHOS with degree of polymerization (DP) 2-6 as substrate revealed that SmChiD hydrolyzed DP2 with a chitobiase activity and showed TG activity on CHOS with DP3-6, producing longer chain CHOS. But, the TG products were further hydrolyzed to shorter chain CHOS with DP1-2 products. SmChiD with its unique catalytic properties, could be a potential enzyme for the production of long chain CHOS and also for the preparation of efficient enzyme cocktails for chitin degradation.
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Affiliation(s)
- Papa Rao Vaikuntapu
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Samudrala Rambabu
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Jogi Madhuprakash
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India.
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63
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Periplasmic Cytophaga hutchinsonii Endoglucanases Are Required for Use of Crystalline Cellulose as the Sole Source of Carbon and Energy. Appl Environ Microbiol 2016; 82:4835-4845. [PMID: 27260354 DOI: 10.1128/aem.01298-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The soil bacterium Cytophaga hutchinsonii actively digests crystalline cellulose by a poorly understood mechanism. Genome analyses identified nine genes predicted to encode endoglucanases with roles in this process. No predicted cellobiohydrolases, which are usually involved in the utilization of crystalline cellulose, were identified. Chromosomal deletions were performed in eight of the endoglucanase-encoding genes: cel5A, cel5B, cel5C, cel9A, cel9B, cel9C, cel9E, and cel9F Each mutant retained the ability to digest crystalline cellulose, although the deletion of cel9C caused a modest decrease in cellulose utilization. Strains with multiple deletions were constructed to identify the critical cellulases. Cells of a mutant lacking both cel5B and cel9C were completely deficient in growth on cellulose. Cell fractionation and biochemical analyses indicate that Cel5B and Cel9C are periplasmic nonprocessive endoglucanases. The requirement of periplasmic endoglucanases for cellulose utilization suggests that cellodextrins are transported across the outer membrane during this process. Bioinformatic analyses predict that Cel5A, Cel9A, Cel9B, Cel9D, and Cel9E are secreted across the outer membrane by the type IX secretion system, which has been linked to cellulose utilization. These secreted endoglucanases may perform the initial digestion within amorphous regions on the cellulose fibers, releasing oligomers that are transported into the periplasm for further digestion by Cel5B and Cel9C. The results suggest that both cell surface and periplasmic endoglucanases are required for the growth of C. hutchinsonii on cellulose and that novel cell surface proteins may solubilize and transport cellodextrins across the outer membrane. IMPORTANCE The bacterium Cytophaga hutchinsonii digests crystalline cellulose by an unknown mechanism. It lacks processive cellobiohydrolases that are often involved in cellulose digestion. Critical cellulolytic enzymes were identified by genetic analyses. Intracellular (periplasmic) nonprocessive endoglucanases performed an important role in cellulose utilization. The results suggest a model involving partial digestion at the cell surface, solubilization and uptake of cellodextrins across the outer membrane by an unknown mechanism, and further digestion within the periplasm. The ability to sequester cellodextrins and digest them intracellularly may limit losses of soluble cellobiose to other organisms. C. hutchinsonii uses an unusual approach to digest cellulose and is a potential source of novel proteins to increase the efficiency of conversion of cellulose into soluble sugars and biofuels.
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Nishioka T, Elsharkawy MM, Suga H, Kageyama K, Hyakumachi M, Shimizu M. Development of Culture Medium for the Isolation of Flavobacterium and Chryseobacterium from Rhizosphere Soil. Microbes Environ 2016; 31:104-10. [PMID: 27098502 PMCID: PMC4912144 DOI: 10.1264/jsme2.me15144] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
An effective medium designated phosphate separately autoclaved Reasoner’s 2A supplemented with cycloheximide and tobramycin (PSR2A-C/T) has been developed for the isolation of Flavobacterium and Chryseobacterium strains from the plant rhizosphere. It consists of Reasoner’s 2A agar (R2A) prepared by autoclaving phosphate and agar separately and supplementing with 50 mg L−1 cycloheximide and 1 mg L−1 tobramycin. A comparison was made among the following nine media: PSR2A-C/T, PSR2A-C/T supplemented with NaCl, R2A agar, R2A agar supplemented with cycloheximide and tobramycin, 1/4-strength tryptic soy agar (TSA), 1/10-strength TSA, soil-extract agar, Schaedler anaerobe agar (SAA), and SAA supplemented with gramicidin, for the recovery of Flavobacterium and Chryseobacterium strains from the Welsh onion rhizosphere. Flavobacterium strains were only isolated on PSR2A-C/T, and the recovery rate of Chryseobacterium strains was higher from PSR2A-C/T than from the eight other media. In order to confirm the effectiveness of PSR2A-C/T, bacteria were isolated from onion rhizosphere soil with this medium. Flavobacterium and Chryseobacterium strains were successfully isolated from this sample at a similar rate to that from the Welsh onion rhizosphere.
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Affiliation(s)
- Tomoki Nishioka
- Graduate School of Applied Biological Sciences, Gifu University
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The outer-membrane export signal of Porphyromonas gingivalis type IX secretion system (T9SS) is a conserved C-terminal β-sandwich domain. Sci Rep 2016; 6:23123. [PMID: 27005013 PMCID: PMC4804311 DOI: 10.1038/srep23123] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/26/2016] [Indexed: 12/31/2022] Open
Abstract
In the recently characterized Type IX Secretion System (T9SS), the conserved C-terminal domain (CTD) in secreted proteins functions as an outer membrane translocation signal for export of virulence factors to the cell surface in the Gram-negative Bacteroidetes phylum. In the periodontal pathogen Porphyromonas gingivalis, the CTD is cleaved off by PorU sortase in a sequence-independent manner, and anionic lipopolysaccharide (A-LPS) is attached to many translocated proteins, thus anchoring them to the bacterial surface. Here, we solved the atomic structure of the CTD of gingipain B (RgpB) from P. gingivalis, alone and together with a preceding immunoglobulin-superfamily domain (IgSF). The CTD was found to possess a typical Ig-like fold encompassing seven antiparallel β-strands organized in two β-sheets, packed into a β-sandwich structure that can spontaneously dimerise through C-terminal strand swapping. Small angle X-ray scattering (SAXS) revealed no fixed orientation of the CTD with respect to the IgSF. By introducing insertion or substitution of residues within the inter-domain linker in the native protein, we were able to show that despite the region being unstructured, it nevertheless is resistant to general proteolysis. These data suggest structural motifs located in the two adjacent Ig-like domains dictate the processing of CTDs by the T9SS secretion pathway.
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Kadowaki T, Yukitake H, Naito M, Sato K, Kikuchi Y, Kondo Y, Shoji M, Nakayama K. A two-component system regulates gene expression of the type IX secretion component proteins via an ECF sigma factor. Sci Rep 2016; 6:23288. [PMID: 26996145 PMCID: PMC4800418 DOI: 10.1038/srep23288] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 03/03/2016] [Indexed: 12/19/2022] Open
Abstract
The periodontopathogen Porphyromonas gingivalis secretes potent pathogenic proteases, gingipains, via the type IX secretion system (T9SS). This system comprises at least 11 components; however, the regulatory mechanism of their expression has not yet been elucidated. Here, we found that the PorY (PGN_2001)-PorX (PGN_1019)-SigP (PGN_0274) cascade is involved in the regulation of T9SS. Surface plasmon resonance (SPR) analysis revealed a direct interaction between a recombinant PorY (rPorY) and a recombinant PorX (rPorX). rPorY autophosphorylated and transferred a phosphoryl group to rPorX in the presence of Mn2+. These results demonstrate that PorX and PorY act as a response regulator and a histidine kinase, respectively, of a two component system (TCS), although they are separately encoded on the chromosome. T9SS component-encoding genes were down-regulated in a mutant deficient in a putative extracytoplasmic function (ECF) sigma factor, PGN_0274 (SigP), similar to the porX mutant. Electrophoretic gel shift assays showed that rSigP bound to the putative promoter regions of T9SS component-encoding genes. The SigP protein was lacking in the porX mutant. Co-immunoprecipitation and SPR analysis revealed the direct interaction between SigP and PorX. Together, these results indicate that the PorXY TCS regulates T9SS-mediated protein secretion via the SigP ECF sigma factor.
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Affiliation(s)
- Tomoko Kadowaki
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.,Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Yuichiro Kikuchi
- Department of Microbiology, Tokyo Dental College, Tokyo 101-0061, Japan
| | - Yoshio Kondo
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.,Department of Pediatric Dentistry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan
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Involvement of the Type IX Secretion System in Capnocytophaga ochracea Gliding Motility and Biofilm Formation. Appl Environ Microbiol 2016; 82:1756-1766. [PMID: 26729712 DOI: 10.1128/aem.03452-15] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/30/2015] [Indexed: 11/20/2022] Open
Abstract
Capnocytophaga ochracea is a Gram-negative, rod-shaped bacterium that demonstrates gliding motility when cultured on solid agar surfaces. C. ochracea possesses the ability to form biofilms; however, factors involved in biofilm formation by this bacterium are unclear. A type IX secretion system (T9SS) in Flavobacterium johnsoniae was shown to be involved in the transport of proteins (e.g., several adhesins) to the cell surface. Genes orthologous to those encoding T9SS proteins in F. johnsoniae have been identified in the genome of C. ochracea; therefore, the T9SS may be involved in biofilm formation by C. ochracea. Here we constructed three ortholog-deficient C. ochracea mutants lacking sprB (which encodes a gliding motility adhesin) or gldK or sprT (which encode T9SS proteins in F. johnsoniae). Gliding motility was lost in each mutant, suggesting that, in C. ochracea, the proteins encoded by sprB, gldK, and sprT are necessary for gliding motility, and SprB is transported to the cell surface by the T9SS. For the ΔgldK, ΔsprT, and ΔsprB strains, the amounts of crystal violet-associated biofilm, relative to wild-type values, were 49%, 34%, and 65%, respectively, at 48 h. Confocal laser scanning and scanning electron microscopy revealed that the biofilms formed by wild-type C. ochracea were denser and bacterial cells were closer together than in those formed by the mutant strains. Together, these results indicate that proteins exported by the T9SS are key elements of the gliding motility and biofilm formation of C. ochracea.
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Larsbrink J, Zhu Y, Kharade SS, Kwiatkowski KJ, Eijsink VGH, Koropatkin NM, McBride MJ, Pope PB. A polysaccharide utilization locus from Flavobacterium johnsoniae enables conversion of recalcitrant chitin. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:260. [PMID: 27933102 PMCID: PMC5127042 DOI: 10.1186/s13068-016-0674-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/17/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND Chitin is the second most abundant polysaccharide on earth and as such a great target for bioconversion applications. The phylum Bacteroidetes is one of nature's most ubiquitous bacterial lineages and is essential in the global carbon cycle with many members being highly efficient degraders of complex carbohydrates. However, despite their specialist reputation in carbohydrate conversion, mechanisms for degrading recalcitrant crystalline polysaccharides such as chitin and cellulose are hitherto unknown. RESULTS Here we describe a complete functional analysis of a novel polysaccharide utilization locus (PUL) in the soil Bacteroidete Flavobacterium johnsoniae, tailored for conversion of chitin. The F. johnsoniae chitin utilization locus (ChiUL) consists of eleven contiguous genes encoding carbohydrate capture and transport proteins, enzymes, and a two-component sensor-regulator system. The key chitinase (ChiA) encoded by ChiUL is atypical in terms of known Bacteroidetes-affiliated PUL mechanisms as it is not anchored to the outer cell membrane and consists of multiple catalytic domains. We demonstrate how the extraordinary hydrolytic efficiency of ChiA derives from synergy between its multiple chitinolytic (endo- and exo-acting) and previously unidentified chitin-binding domains. Reverse genetics show that ChiA and PUL-encoded proteins involved in sugar binding, import, and chitin sensing are essential for efficient chitin utilization. Surprisingly, the ChiUL encodes two pairs of SusC/D-like outer membrane proteins. Ligand-binding and structural studies revealed functional differences between the two SusD-like proteins that enhance scavenging of chitin from the environment. The combined results from this study provide insight into the mechanisms employed by Bacteroidetes to degrade recalcitrant polysaccharides and reveal important novel aspects of the PUL paradigm. CONCLUSIONS By combining reverse genetics to map essential PUL genes, structural studies on outer membrane chitin-binding proteins, and enzymology, we provide insight into the mechanisms employed by Bacteroidetes to degrade recalcitrant polysaccharides and introduce a new saccharolytic mechanism used by the phylum Bacteroidetes. The presented discovery and analysis of the ChiUL will greatly benefit future enzyme discovery efforts as well as studies regarding enzymatic intramolecular synergism.
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Affiliation(s)
- Johan Larsbrink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Yongtao Zhu
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, WI 53201 USA
| | - Sampada S. Kharade
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, WI 53201 USA
| | - Kurt J. Kwiatkowski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
| | - Nicole M. Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, WI 53201 USA
| | - Phillip B. Pope
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
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Towards a model for Flavobacterium gliding. Curr Opin Microbiol 2015; 28:93-7. [PMID: 26476806 DOI: 10.1016/j.mib.2015.07.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/14/2015] [Accepted: 07/19/2015] [Indexed: 01/29/2023]
Abstract
Cells of Flavobacterium johnsoniae, a rod-shaped bacterium about 6 μm long, do not have flagella or pili, yet they move over surfaces at speeds of about 2 μm/s. This motion is called gliding. Recent advances in F. johnsoniae research include the discovery of mobile cell-surface adhesins and rotary motors. The puzzle is how rotary motion leads to linear motion. We suggest a possible mechanism, inspired by the snowmobile.
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Flavobacterium gliding motility and the type IX secretion system. Curr Opin Microbiol 2015; 28:72-7. [PMID: 26461123 DOI: 10.1016/j.mib.2015.07.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/14/2015] [Accepted: 07/19/2015] [Indexed: 11/21/2022]
Abstract
Cells of Flavobacterium johnsoniae crawl rapidly over surfaces in a process called gliding motility. These cells do not have flagella or pili but instead rely on a novel motility machine composed of proteins that are unique to the phylum Bacteroidetes. The motility adhesins SprB and RemA are propelled along the cell surface by the still poorly-defined gliding motor. Interaction of these adhesins with a surface results in translocation of the cell. SprB and RemA are delivered to the cell surface by the type IX secretion system (T9SS). T9SSs are confined to but common in the phylum Bacteroidetes. Transmembrane components of the T9SS may perform roles in both secretion and gliding motility.
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Cretoiu MS, Berini F, Kielak AM, Marinelli F, van Elsas JD. A novel salt-tolerant chitobiosidase discovered by genetic screening of a metagenomic library derived from chitin-amended agricultural soil. Appl Microbiol Biotechnol 2015; 99:8199-215. [PMID: 26040993 PMCID: PMC4561078 DOI: 10.1007/s00253-015-6639-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 12/04/2022]
Abstract
Here, we report on the construction of a metagenomic library from a chitin-amended disease-suppressive agricultural soil and its screening for genes that encode novel chitinolytic enzymes. The library, constructed in fosmids in an Escherichia coli host, comprised 145,000 clones containing inserts of sizes of 21 to 40 kb, yielding a total of approximately 5.8 GB of cloned soil DNA. Using genetic screenings by repeated PCR cycles aimed to detect gene sequences of the bacterial chitinase A-class (hereby named chi A genes), we identified and characterized five fosmids carrying candidate genes for chitinolytic enzymes. The analysis thus allowed access to the genomic (fosmid-borne) context of these genes. Using the chiA-targeted PCR, which is based on degenerate primers, the five fosmids all produced amplicons, of which the sequences were related to predicted chitinolytic enzyme-encoding genes of four different host organisms, including Stenotrophomonas maltophilia. Sequencing and de novo annotation of the fosmid inserts confirmed that each one of these carried one or more open reading frames that were predicted to encode enzymes active on chitin, including one for a chitin deacetylase. Moreover, the genetic contexts in which the putative chitinolytic enzyme-encoding genes were located were unique per fosmid. Specifically, inserts from organisms related to Burkholderia sp., Acidobacterium sp., Aeromonas veronii, and the chloroflexi Nitrolancetus hollandicus and/or Ktedonobacter racemifer were obtained. Remarkably, the S. maltophilia chiA-like gene was found to occur in two different genetic contexts (related to N. hollandicus/K. racemifer), indicating the historical occurrence of genetic reshufflings in this part of the soil microbiota. One fosmid containing the insert composed of DNA from the N. hollandicus-like organism (denoted 53D1) was selected for further work. Using subcloning procedures, its putative gene for a chitinolytic enzyme was successfully brought to expression in an E. coli host. On the basis of purified protein preparations, the produced protein was characterized as a chitobiosidase of 43.6 kDa, with a pI of 4.83. Given its activity spectrum, it can be typified as a halotolerant chitobiosidase.
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Affiliation(s)
- Mariana Silvia Cretoiu
- />Department of Microbial Ecology, CEES, University of Groningen, Groningen, The Netherlands
- />Department of Marine Microbiology, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands
| | - Francesca Berini
- />Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- />“The Protein Factory” Research Center, Politecnico of Milano, ICRM CNR Milano and University of Insubria, Varese, Italy
| | - Anna Maria Kielak
- />Department of Microbial Ecology, The Netherlands Institute of Ecology (NIOO), Wageningen, The Netherlands
| | - Flavia Marinelli
- />Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- />“The Protein Factory” Research Center, Politecnico of Milano, ICRM CNR Milano and University of Insubria, Varese, Italy
| | - Jan Dirk van Elsas
- />Department of Microbial Ecology, CEES, University of Groningen, Groningen, The Netherlands
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Xu G, Zhao Y, Du L, Qian G, Liu F. Hfq regulates antibacterial antibiotic biosynthesis and extracellular lytic-enzyme production in Lysobacter enzymogenes OH11. Microb Biotechnol 2015; 8:499-509. [PMID: 25683974 PMCID: PMC4408182 DOI: 10.1111/1751-7915.12246] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/31/2014] [Accepted: 11/02/2014] [Indexed: 12/14/2022] Open
Abstract
Lysobacter enzymogenes is an important biocontrol agent with the ability to produce a variety of lytic enzymes and novel antibiotics. Little is known about their regulatory mechanisms. Understanding these will be helpful for improving biocontrol of crop diseases and potential medical application. In the present study, we generated an hfq (encoding a putative ribonucleic acid chaperone) deletion mutant, and then utilized a new genomic marker-free method to construct an hfq-complemented strain. We showed for the first time that Hfq played a pleiotropic role in regulating the antibacterial antibiotic biosynthesis and extracellular lytic enzyme activity in L. enzymogenes. Mutation of hfq significantly increased the yield of WAP-8294A2 (an antibacterial antibiotic) as well as the transcription of its key biosynthetic gene, waps1. However, inactivation of hfq almost abolished the extracellular chitinase activity and remarkably decreased the activity of both extracellular protease and cellulase in L. enzymogenes. We further showed that the regulation of hfq in extracellular chitinase production was in part through the impairment of the secretion of chitinase A. Collectively, our results reveal the regulatory roles of hfq in antibiotic metabolite and extracellular lytic enzymes in the underexplored genus of Lysobacter.
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Affiliation(s)
- Gaoge Xu
- College of Plant Protection, Nanjing Agricultural University, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing, 210095, China
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Nakayama K. Porphyromonas gingivalis and related bacteria: from colonial pigmentation to the type IX secretion system and gliding motility. J Periodontal Res 2014; 50:1-8. [PMID: 25546073 PMCID: PMC4674972 DOI: 10.1111/jre.12255] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2014] [Indexed: 12/22/2022]
Abstract
Porphyromonas gingivalis is a gram-negative, non-motile, anaerobic bacterium implicated as a major pathogen in periodontal disease. P. gingivalis grows as black-pigmented colonies on blood agar, and many bacteriologists have shown interest in this property. Studies of colonial pigmentation have revealed a number of important findings, including an association with the highly active extracellular and surface proteinases called gingipains that are found in P. gingivalis. The Por secretion system, a novel type IX secretion system (T9SS), has been implicated in gingipain secretion in studies using non-pigmented mutants. In addition, many potent virulence proteins, including the metallocarboxypeptidase CPG70, 35 kDa hemin-binding protein HBP35, peptidylarginine deiminase PAD and Lys-specific serine endopeptidase PepK, are secreted through the T9SS. These findings have not been limited to P. gingivalis but have been extended to other bacteria belonging to the phylum Bacteroidetes. Many Bacteroidetes species possess the T9SS, which is associated with gliding motility for some of these bacteria.
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Affiliation(s)
- K Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Flavobacterium johnsoniae PorV is required for secretion of a subset of proteins targeted to the type IX secretion system. J Bacteriol 2014; 197:147-58. [PMID: 25331433 DOI: 10.1128/jb.02085-14] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Flavobacterium johnsoniae exhibits gliding motility and digests many polysaccharides, including chitin. A novel protein secretion system, the type IX secretion system (T9SS), is required for gliding and chitin utilization. The T9SS secretes the cell surface motility adhesins SprB and RemA and the chitinase ChiA. Proteins involved in secretion by the T9SS include GldK, GldL, GldM, GldN, SprA, SprE, and SprT. Porphyromonas gingivalis has orthologs for each of these that are required for secretion of gingipain protease virulence factors by its T9SS. P. gingivalis porU and porV have also been linked to T9SS-mediated secretion, and F. johnsoniae has orthologs of these. Mutations in F. johnsoniae porU and porV were constructed to determine if they function in secretion. Cells of a porV deletion mutant were deficient in chitin utilization and failed to secrete ChiA. They were also deficient in secretion of the motility adhesin RemA but retained the ability to secrete SprB. SprB is involved in gliding motility and is needed for formation of spreading colonies on agar, and the porV mutant exhibited gliding motility and formed spreading colonies. However, the porV mutant was partially deficient in attachment to glass, apparently because of the absence of RemA and other adhesins on the cell surface. The porV mutant also appeared to be deficient in secretion of numerous other proteins that have carboxy-terminal domains associated with targeting to the T9SS. PorU was not required for secretion of ChiA, RemA, or SprB, indicating that it does not play an essential role in the F. johnsoniae T9SS.
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