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Ngom SI, Maski S, Rached B, Chouati T, Oliveira Correia L, Juste C, Meylheuc T, Henrissat B, El Fahime E, Amar M, Béra-Maillet C. Exploring the hemicellulolytic properties and safety of Bacillus paralicheniformis as stepping stone in the use of new fibrolytic beneficial microbes. Sci Rep 2023; 13:22785. [PMID: 38129471 PMCID: PMC10740013 DOI: 10.1038/s41598-023-49724-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Bacillus strains from the Moroccan Coordinated Collections of Microorganisms (CCMM) were characterised and tested for fibrolytic function and safety properties that would be beneficial for maintaining intestinal homeostasis, and recommend beneficial microbes in the field of health promotion research. Forty strains were investigated for their fibrolytic activities towards complex purified polysaccharides and natural fibres representative of dietary fibres (DFs) entering the colon for digestion. We demonstrated hemicellulolytic activities for nine strains of Bacillus aerius, re-identified as Bacillus paralicheniformis and Bacillus licheniformis, using xylan, xyloglucan or lichenan as purified polysaccharides, and orange, apple and carrot natural fibres, with strain- and substrate-dependent production of glycoside hydrolases (GHs). Our combined methods, based on enzymatic assays, secretome, and genome analyses, highlighted the hemicellulolytic activities of B. paralicheniformis and the secretion of specific glycoside hydrolases, in particular xylanases, compared to B. licheniformis. Genomic features of these strains revealed a complete set of GH genes dedicated to the degradation of various polysaccharides from DFs, including cellulose, hemicellulose and pectin, which may confer on the strains the ability to digest a variety of DFs. Preliminary experiments on the safety and immunomodulatory properties of B. paralicheniformis fibrolytic strains were evaluated in light of applications as beneficial microbes' candidates for health improvement. B. paralicheniformis CCMM B969 was therefore proposed as a new fibrolytic beneficial microbe candidate.
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Affiliation(s)
- Serigne Inssa Ngom
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Soufiane Maski
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Département de Biologie, Faculté des Sciences, Université Mohammed V, Rabat, Morocco
| | - Bahia Rached
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Laboratoire de Chimie-Physique et Biotechnologies des Biomolécules et Matériaux/Equipe Microbiologie Biomolécules et Biotechnologies, Faculté des Sciences et Techniques, Mohammedia, Morocco
| | - Taha Chouati
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Biologie médicale, Pathologie humaine et Expérimentale et Environnement, Faculté de Médecine et de pharmacie de Rabat, Rabat, Morocco
| | - Lydie Oliveira Correia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, PAPPSO, 78350, Jouy-en-Josas, France
| | - Catherine Juste
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Thierry Meylheuc
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, MIMA2, 78350, Jouy en Josas, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, 13288, Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Elmostafa El Fahime
- Plateforme Génomique Fonctionnelle, Unité d'Appui Technique à la Recherche Scientifique, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Biologie médicale, Pathologie humaine et Expérimentale et Environnement, Faculté de Médecine et de pharmacie de Rabat, Rabat, Morocco
| | - Mohamed Amar
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
- Collections Coordonnées Marocaines de Microorganismes, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco
| | - Christel Béra-Maillet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France.
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco.
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Zhao T, Yue H, Peng J, Nie Y, Wu L, Li T, Niu W, Li C, Zhang Z, Li M, Ding K. Degradation of xylan by human gut Bacteroides xylanisolvens XB1A. Carbohydr Polym 2023; 315:121005. [PMID: 37230606 DOI: 10.1016/j.carbpol.2023.121005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/26/2023] [Accepted: 05/08/2023] [Indexed: 05/27/2023]
Abstract
Although many polysaccharides utilization loci (PULs) have been investigated by genomics and transcriptomics, the detailed functional characterization lags severely behind. We hypothesize that PULs on the genome of Bacteroides xylanisolvens XB1A (BX) dictate the degradation of complex xylan. To address, xylan S32 isolated from Dendrobium officinale was employed as a sample polysaccharide. We firstly showed that xylan S32 promoted the growth of BX which might degrade xylan S32 into monosaccharides and oligosaccharides. We further showed that this degradation was performed mainly via two discrete PULs in the genome of BX. Briefly, a new surface glycan binding protein (SGBP) BX_29290SGBP was identified, and shown to be essential for the growth of BX on xylan S32. Two cell surface endo-xylanases Xyn10A and Xyn10B cooperated to deconstruct the xylan S32. Intriguingly, genes encoding Xyn10A and Xyn10B were mainly distributed in the genome of Bacteroides spp. In addition, BX metabolized xylan S32 to produce short chain fatty acids (SCFAs) and folate. Taken together, these findings provide new evidence to understand the food source of BX and the BX-directed intervention strategy by xylan.
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Affiliation(s)
- Tingting Zhao
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu Province 210029, PR China; Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Han Yue
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Junfeng Peng
- Department of Pancreatic-biliary Surgery, Naval Medical University, Shanghai, PR China
| | - Yingmin Nie
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China; University of Chinese Academy of Science, No.19A Yuquan Road, Beijing 100049, PR China
| | - Longzhen Wu
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Tingting Li
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Wei Niu
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Chuan Li
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Zhengqing Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China.
| | - Meixia Li
- Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
| | - Kan Ding
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu Province 210029, PR China; Carbohydrate-Based Drug Research Center, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China; University of Chinese Academy of Science, No.19A Yuquan Road, Beijing 100049, PR China; Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Science, SSIP Healthcare and Medicine Demonstration Zone, Zhongshan Tsuihang New District, Zhongshan 528400, PR China.
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Pavarina GC, Lemos EGDM, Lima NSM, Pizauro JM. Characterization of a new bifunctional endo-1,4-β-xylanase/esterase found in the rumen metagenome. Sci Rep 2021; 11:10440. [PMID: 34001974 PMCID: PMC8128909 DOI: 10.1038/s41598-021-89916-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 04/26/2021] [Indexed: 12/13/2022] Open
Abstract
Metagenomic data mining of the Nellore cattle rumen microbiota identified a new bifunctional enzyme, endo-1,4-β-xylanase/esterase, which was subsequently overexpressed in E. coli BL21 (DE3). This enzyme was stable at pH intervals of 5 to 6.5 and temperatures between 30 and 45 °C, and under the test conditions, it had a Vmax of 30.959 ± 2.334 µmol/min/mg, Km of 3.6 ± 0.6 mM and kcat of 2.323 ± 175 s-1. Additionally, the results showed that the enzyme is tolerant to NaCl and organic solvents and therefore is suitable for industrial environments. Xylanases are widely applicable, and the synergistic activity of endo-1,4-β-xylanase/esterase in a single molecule will improve the degradation efficiency of heteroxylans via the creation of xylanase binding sites. Therefore, this new molecule has the potential for use in lignocellulosic biomass processing and as an animal feed food additive and could improve xylooligosaccharide production efficiency.
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Affiliation(s)
- Gabriella Cavazzini Pavarina
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinarian Sciences, Sao Paulo State University (Unesp), Jaboticabal, Sao Paulo, Brazil
| | - Eliana Gertrudes de Macedo Lemos
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Molecular Biology Laboratory, Bioenergy Research Institute (IPBEN), Jaboticabal, Sao Paulo, Brazil
| | - Natália Sarmanho Monteiro Lima
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinarian Sciences, Sao Paulo State University (Unesp), Jaboticabal, Sao Paulo, Brazil
| | - João Martins Pizauro
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.
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Cronin P, Joyce SA, O’Toole PW, O’Connor EM. Dietary Fibre Modulates the Gut Microbiota. Nutrients 2021; 13:nu13051655. [PMID: 34068353 PMCID: PMC8153313 DOI: 10.3390/nu13051655] [Citation(s) in RCA: 212] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 12/14/2022] Open
Abstract
Dietary fibre has long been established as a nutritionally important, health-promoting food ingredient. Modern dietary practices have seen a significant reduction in fibre consumption compared with ancestral habits. This is related to the emergence of low-fibre “Western diets” associated with industrialised nations, and is linked to an increased prevalence of gut diseases such as inflammatory bowel disease, obesity, type II diabetes mellitus and metabolic syndrome. The characteristic metabolic parameters of these individuals include insulin resistance, high fasting and postprandial glucose, as well as high plasma cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Gut microbial signatures are also altered significantly in these cohorts, suggesting a causative link between diet, microbes and disease. Dietary fibre consumption has been hypothesised to reverse these changes through microbial fermentation and the subsequent production of short-chain fatty acids (SCFA), which improves glucose and lipid parameters in individuals who harbour diseases associated with dysfunctional metabolism. This review article examines how different types of dietary fibre can differentially alter glucose and lipid metabolism through changes in gut microbiota composition and function.
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Affiliation(s)
- Peter Cronin
- Department of Biological Sciences, University of Limerick, V94 T9PX Limerick, Ireland;
- APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland; (S.A.J.); (P.W.O.)
| | - Susan A. Joyce
- APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland; (S.A.J.); (P.W.O.)
- School of Biochemistry and Cell Biology, University College Cork, T12 K8AF Cork, Ireland
| | - Paul W. O’Toole
- APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland; (S.A.J.); (P.W.O.)
- Department of Microbiology, University College Cork, T12 K8AF Cork, Ireland
| | - Eibhlís M. O’Connor
- Department of Biological Sciences, University of Limerick, V94 T9PX Limerick, Ireland;
- APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland; (S.A.J.); (P.W.O.)
- Health Research Institute, University of Limerick, V94 T9PX Limerick, Ireland
- Correspondence:
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Cherry P, Yadav S, Strain CR, Allsopp PJ, McSorley EM, Ross RP, Stanton C. Prebiotics from Seaweeds: An Ocean of Opportunity? Mar Drugs 2019; 17:E327. [PMID: 31159359 PMCID: PMC6627129 DOI: 10.3390/md17060327] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/27/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023] Open
Abstract
Seaweeds are an underexploited and potentially sustainable crop which offer a rich source of bioactive compounds, including novel complex polysaccharides, polyphenols, fatty acids, and carotenoids. The purported efficacies of these phytochemicals have led to potential functional food and nutraceutical applications which aim to protect against cardiometabolic and inflammatory risk factors associated with non-communicable diseases, such as obesity, type 2 diabetes, metabolic syndrome, cardiovascular disease, inflammatory bowel disease, and some cancers. Concurrent understanding that perturbations of gut microbial composition and metabolic function manifest throughout health and disease has led to dietary strategies, such as prebiotics, which exploit the diet-host-microbe paradigm to modulate the gut microbiota, such that host health is maintained or improved. The prebiotic definition was recently updated to "a substrate that is selectively utilised by host microorganisms conferring a health benefit", which, given that previous discussion regarding seaweed prebiotics has focused upon saccharolytic fermentation, an opportunity is presented to explore how non-complex polysaccharide components from seaweeds may be metabolised by host microbial populations to benefit host health. Thus, this review provides an innovative approach to consider how the gut microbiota may utilise seaweed phytochemicals, such as polyphenols, polyunsaturated fatty acids, and carotenoids, and provides an updated discussion regarding the catabolism of seaweed-derived complex polysaccharides with potential prebiotic activity. Additional in vitro screening studies and in vivo animal studies are needed to identify potential prebiotics from seaweeds, alongside untargeted metabolomics to decipher microbial-derived metabolites from seaweeds. Furthermore, controlled human intervention studies with health-related end points to elucidate prebiotic efficacy are required.
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Affiliation(s)
- Paul Cherry
- Nutrition Innovation Centre for Food and Health, Ulster University, Cromore Road, Coleraine, Co. Londonderry BT52 1SA, UK.
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
- APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland.
| | - Supriya Yadav
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
| | - Conall R Strain
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
- APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland.
| | - Philip J Allsopp
- Nutrition Innovation Centre for Food and Health, Ulster University, Cromore Road, Coleraine, Co. Londonderry BT52 1SA, UK.
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food and Health, Ulster University, Cromore Road, Coleraine, Co. Londonderry BT52 1SA, UK.
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland.
- College of Science, Engineering and Food Science, University College Cork, Cork T12 K8AF, Ireland.
| | - Catherine Stanton
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.
- APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland.
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Gene Expression and Molecular Characterization of a Xylanase from Chicken Cecum Metagenome. Int J Microbiol 2017; 2017:4018398. [PMID: 28751915 PMCID: PMC5511640 DOI: 10.1155/2017/4018398] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/15/2017] [Accepted: 05/23/2017] [Indexed: 12/26/2022] Open
Abstract
A xylanase gene xynAMG1 with a 1,116-bp open reading frame, encoding an endo-β-1,4-xylanase, was cloned from a chicken cecum metagenome. The translated XynAMG1 protein consisted of 372 amino acids including a putative signal peptide of 23 amino acids. The calculated molecular mass of the mature XynAMG1 was 40,013 Da, with a theoretical pI value of 5.76. The amino acid sequence of XynAMG1 showed 59% identity to endo-β-1,4-xylanase from Prevotella bryantii and Prevotella ruminicola and 58% identity to that from Prevotella copri. XynAMG1 has two conserved motifs, DVVNE and TEXD, containing two active site glutamates and an invariant asparagine, characteristic of GH10 family xylanase. The xynAMG1 gene without signal peptide sequence was cloned and fused with thioredoxin protein (Trx.Tag) in pET-32a plasmid and overexpressed in Escherichia coli Tuner™(DE3)pLysS. The purified mature XynAMG1 was highly salt-tolerant and stable and displayed higher than 96% of its catalytic activity in the reaction containing 1 to 4 M NaCl. It was only slightly affected by common organic solvents added in aqueous solution to up to 5 M. This chicken cecum metagenome-derived xylanase has potential applications in animal feed additives and industrial enzymatic processes requiring exposure to high concentrations of salt and organic solvents.
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Despres J, Forano E, Lepercq P, Comtet-Marre S, Jubelin G, Chambon C, Yeoman CJ, Berg Miller ME, Fields CJ, Martens E, Terrapon N, Henrissat B, White BA, Mosoni P. Xylan degradation by the human gut Bacteroides xylanisolvens XB1A(T) involves two distinct gene clusters that are linked at the transcriptional level. BMC Genomics 2016; 17:326. [PMID: 27142817 PMCID: PMC4855328 DOI: 10.1186/s12864-016-2680-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/28/2016] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Plant cell wall (PCW) polysaccharides and especially xylans constitute an important part of human diet. Xylans are not degraded by human digestive enzymes in the upper digestive tract and therefore reach the colon where they are subjected to extensive degradation by some members of the symbiotic microbiota. Xylanolytic bacteria are the first degraders of these complex polysaccharides and they release breakdown products that can have beneficial effects on human health. In order to understand better how these bacteria metabolize xylans in the colon, this study was undertaken to investigate xylan breakdown by the prominent human gut symbiont Bacteroides xylanisolvens XB1A(T). RESULTS Transcriptomic analyses of B. xylanisolvens XB1A(T) grown on insoluble oat-spelt xylan (OSX) at mid- and late-log phases highlighted genes in a polysaccharide utilization locus (PUL), hereafter called PUL 43, and genes in a fragmentary remnant of another PUL, hereafter referred to as rPUL 70, which were highly overexpressed on OSX relative to glucose. Proteomic analyses supported the up-regulation of several genes belonging to PUL 43 and showed the important over-production of a CBM4-containing GH10 endo-xylanase. We also show that PUL 43 is organized in two operons and that the knockout of the PUL 43 sensor/regulator HTCS gene blocked the growth of the mutant on insoluble OSX and soluble wheat arabinoxylan (WAX). The mutation not only repressed gene expression in the PUL 43 operons but also repressed gene expression in rPUL 70. CONCLUSION This study shows that xylan degradation by B. xylanisolvens XB1A(T) is orchestrated by one PUL and one PUL remnant that are linked at the transcriptional level. Coupled to studies on other xylanolytic Bacteroides species, our data emphasize the importance of one peculiar CBM4-containing GH10 endo-xylanase in xylan breakdown and that this modular enzyme may be used as a functional marker of xylan degradation in the human gut. Our results also suggest that B. xylanisolvens XB1A(T) has specialized in the degradation of xylans of low complexity. This functional feature may provide a niche to all xylanolytic bacteria harboring similar PULs. Further functional and ecological studies on fibrolytic Bacteroides species are needed to better understand their role in dietary fiber degradation and their impact on intestinal health.
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Affiliation(s)
- Jordane Despres
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France
| | - Evelyne Forano
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France
| | - Pascale Lepercq
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France
| | - Sophie Comtet-Marre
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France
| | - Gregory Jubelin
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France
| | - Christophe Chambon
- INRA, Plate-forme d'Exploration du Métabolisme, 63122, Saint-Genès Champanelle, France
| | - Carl J Yeoman
- Department of Animal and Range Sciences, Montana State University, Bozeman, MT, 59718, USA
| | - Margaret E Berg Miller
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Christopher J Fields
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Eric Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Nicolas Terrapon
- Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257 CNRS, Université Aix-Marseille, 163 Avenue de Luminy, 13288, Marseille, France
- INRA, USC 1408 AFMB, 13288, Marseille, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257 CNRS, Université Aix-Marseille, 163 Avenue de Luminy, 13288, Marseille, France
- INRA, USC 1408 AFMB, 13288, Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Bryan A White
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Pascale Mosoni
- Institut National de la recherche Agronomique (INRA), UR454 Microbiologie, Centre de Clermont-Ferrand-Theix, 63122, Saint-Genès-Champanelle, France.
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Santos CR, Hoffmam ZB, de Matos Martins VP, Zanphorlin LM, de Paula Assis LH, Honorato RV, Lopes de Oliveira PS, Ruller R, Murakami MT. Molecular mechanisms associated with xylan degradation by Xanthomonas plant pathogens. J Biol Chem 2014; 289:32186-32200. [PMID: 25266726 PMCID: PMC4231694 DOI: 10.1074/jbc.m114.605105] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/22/2014] [Indexed: 11/06/2022] Open
Abstract
Xanthomonas pathogens attack a variety of economically relevant plants, and their xylan CUT system (carbohydrate utilization with TonB-dependent outer membrane transporter system) contains two major xylanase-related genes, xynA and xynB, which influence biofilm formation and virulence by molecular mechanisms that are still elusive. Herein, we demonstrated that XynA is a rare reducing end xylose-releasing exo-oligoxylanase and not an endo-β-1,4-xylanase as predicted. Structural analysis revealed that an insertion in the β7-α7 loop induces dimerization and promotes a physical barrier at the +2 subsite conferring this unique mode of action within the GH10 family. A single mutation that impaired dimerization became XynA active against xylan, and high endolytic activity was achieved when this loop was tailored to match a canonical sequence of endo-β-1,4-xylanases, supporting our mechanistic model. On the other hand, the divergent XynB proved to be a classical endo-β-1,4-xylanase, despite the low sequence similarity to characterized GH10 xylanases. Interestingly, this enzyme contains a calcium ion bound nearby to the glycone-binding region, which is required for catalytic activity and structural stability. These results shed light on the molecular basis for xylan degradation by Xanthomonas and suggest how these enzymes synergistically assist infection and pathogenesis. Our findings indicate that XynB contributes to breach the plant cell wall barrier, providing nutrients and facilitating the translocation of effector molecules, whereas the exo-oligoxylanase XynA possibly participates in the suppression of oligosaccharide-induced immune responses.
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Affiliation(s)
- Camila Ramos Santos
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Zaira Bruna Hoffmam
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Vanesa Peixoto de Matos Martins
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Leticia Maria Zanphorlin
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Leandro Henrique de Paula Assis
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Rodrigo Vargas Honorato
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Paulo Sérgio Lopes de Oliveira
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Roberto Ruller
- Bioethanol Science and Technology Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil
| | - Mario Tyago Murakami
- Biosciences National Laboratory and National Center for Research in Energy and Materials, Campinas, São Paulo, 13083-970, Brazil.
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10
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Abstract
Mammals rely entirely on symbiotic microorganisms within their digestive tract to gain energy from plant biomass that is resistant to mammalian digestive enzymes. Especially in herbivorous animals, specialized organs (the rumen, cecum, and colon) have evolved that allow highly efficient fermentation of ingested plant biomass by complex anaerobic microbial communities. We consider here the two most intensively studied, representative gut microbial communities involved in degradation of plant fiber: those of the rumen and the human large intestine. These communities are dominated by bacteria belonging to the Firmicutes and Bacteroidetes phyla. In Firmicutes, degradative capacity is largely restricted to the cell surface and involves elaborate cellulosome complexes in specialized cellulolytic species. By contrast, in the Bacteroidetes, utilization of soluble polysaccharides, encoded by gene clusters (PULs), entails outer membrane binding proteins, and degradation is largely periplasmic or intracellular. Biomass degradation involves complex interplay between these distinct groups of bacteria as well as (in the rumen) eukaryotic microorganisms.
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Affiliation(s)
- Bryan A White
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801;
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11
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Piao H, Froula J, Du C, Kim TW, Hawley ER, Bauer S, Wang Z, Ivanova N, Clark DS, Klenk HP, Hess M. Identification of novel biomass-degrading enzymes from genomic dark matter: Populating genomic sequence space with functional annotation. Biotechnol Bioeng 2014; 111:1550-65. [PMID: 24728961 DOI: 10.1002/bit.25250] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 02/21/2014] [Accepted: 03/24/2014] [Indexed: 11/06/2022]
Abstract
Although recent nucleotide sequencing technologies have significantly enhanced our understanding of microbial genomes, the function of ∼35% of genes identified in a genome currently remains unknown. To improve the understanding of microbial genomes and consequently of microbial processes it will be crucial to assign a function to this "genomic dark matter." Due to the urgent need for additional carbohydrate-active enzymes for improved production of transportation fuels from lignocellulosic biomass, we screened the genomes of more than 5,500 microorganisms for hypothetical proteins that are located in the proximity of already known cellulases. We identified, synthesized and expressed a total of 17 putative cellulase genes with insufficient sequence similarity to currently known cellulases to be identified as such using traditional sequence annotation techniques that rely on significant sequence similarity. The recombinant proteins of the newly identified putative cellulases were subjected to enzymatic activity assays to verify their hydrolytic activity towards cellulose and lignocellulosic biomass. Eleven (65%) of the tested enzymes had significant activity towards at least one of the substrates. This high success rate highlights that a gene context-based approach can be used to assign function to genes that are otherwise categorized as "genomic dark matter" and to identify biomass-degrading enzymes that have little sequence similarity to already known cellulases. The ability to assign function to genes that have no related sequence representatives with functional annotation will be important to enhance our understanding of microbial processes and to identify microbial proteins for a wide range of applications.
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Affiliation(s)
- Hailan Piao
- School of Molecular Biosciences, Washington State University, Richland, Washington, 99352; Pacific Northwest National Laboratory, Richland, Washington
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12
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Two new xylanases with different substrate specificities from the human gut bacterium Bacteroides intestinalis DSM 17393. Appl Environ Microbiol 2014; 80:2084-93. [PMID: 24463968 DOI: 10.1128/aem.03176-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Xylan is an abundant plant cell wall polysaccharide and is a dominant component of dietary fiber. Bacteria in the distal human gastrointestinal tract produce xylanase enzymes to initiate the degradation of this complex heteropolymer. These xylanases typically derive from glycoside hydrolase (GH) families 10 and 11; however, analysis of the genome sequence of the xylan-degrading human gut bacterium Bacteroides intestinalis DSM 17393 revealed the presence of two putative GH8 xylanases. In the current study, we demonstrate that the two genes encode enzymes that differ in activity. The xyn8A gene encodes an endoxylanase (Xyn8A), and rex8A encodes a reducing-end xylose-releasing exo-oligoxylanase (Rex8A). Xyn8A hydrolyzed both xylopentaose (X5) and xylohexaose (X6) to a mixture of xylobiose (X2) and xylotriose (X3), while Rex8A hydrolyzed X3 through X6 to a mixture of xylose (X1) and X2. Moreover, rex8A is located downstream of a GH3 gene (xyl3A) that was demonstrated to exhibit β-xylosidase activity and would be able to further hydrolyze X2 to X1. Mutational analyses of putative active site residues of both Xyn8A and Rex8A confirm their importance in catalysis by these enzymes. Recent genome sequences of gut bacteria reveal an increase in GH8 Rex enzymes, especially among the Bacteroidetes, indicating that these genes contribute to xylan utilization in the human gut.
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13
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Guo N, Zheng J, Wu LS, Tian J, Zhou HB. Engineered bifunctional enzymes of endo-1,4-β-xylanase/endo-1,4-β-mannanase were constructed for synergistically hydrolyzing hemicellulose. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2013.06.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Newly cultured bacteria with broad diversity isolated from eight-week continuous culture enrichments of cow feces on complex polysaccharides. Appl Environ Microbiol 2013; 80:574-85. [PMID: 24212576 DOI: 10.1128/aem.03016-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
One of the functions of the mammalian large intestinal microbiota is the fermentation of plant cell wall components. In ruminant animals, the majority of their nutrients are obtained via pregastric fermentation; however, up to 20% can be recovered from microbial fermentation in the large intestine. Eight-week continuous culture enrichments of cattle feces with cellulose and xylan-pectin were used to isolate bacteria from this community. A total of 459 bacterial isolates were classified phylogenetically using 16S rRNA gene sequencing. Six phyla were represented: Firmicutes (51.9%), Bacteroidetes (30.9%), Proteobacteria (11.1%), Actinobacteria (3.5%), Synergistetes (1.5%), and Fusobacteria (1.1%). The majority of bacterial isolates had <98.5% identity to cultured bacteria with sequences in the Ribosomal Database Project and thus represent new species and/or genera. Within the Firmicutes isolates, most were classified in the families Lachnospiraceae, Ruminococcaceae, Erysipelotrichaceae, and Clostridiaceae I. The majority of the Bacteroidetes were most closely related to Bacteroides thetaiotaomicron, B. ovatus, and B. xylanisolvens and members of the Porphyromonadaceae family. Many of the Firmicutes and Bacteroidetes isolates were related to species demonstrated to possess enzymes which ferment plant cell wall components; the others were hypothesized to cross-feed these bacteria. The microbial communities that arose in these enrichment cultures had broad bacterial diversity. With over 98% of the isolates not represented as previously cultured, there are new opportunities to study the genomic and metabolic capacities of these members of the complex intestinal microbiota.
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15
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Ziemer CJ. Broad diversity and newly cultured bacterial isolates from enrichment of pig feces on complex polysaccharides. MICROBIAL ECOLOGY 2013; 66:448-461. [PMID: 23354293 DOI: 10.1007/s00248-013-0185-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
One of the fascinating functions of mammalian intestinal microbiota is fermentation of plant cell wall components. Eight-week continuous culture enrichments of pig feces with cellulose and xylan/pectin were used to isolate bacteria from this community. A total of 575 bacterial isolates were classified phylogenetically using 16S rRNA gene sequencing. Six phyla were represented in the bacterial isolates: Firmicutes (242), Bacteroidetes (185), Proteobacteria (65), Fusobacteria (55), Actinobacteria (23), and Synergistetes (5). The majority of the bacterial isolates had ≥ 97 % similarity to cultured bacteria with sequences in the RDP, but 179 isolates represent new species and/or genera. Within the Firmicutes isolates, most were classified in the families of Lachnospiraceae, Enterococcaceae, Staphylococcaceae, and Clostridiaceae I. The majority of the Bacteroidetes were most closely related to Bacteroides thetaiotaomicron, Bacteroides ovatus, and B. xylanisolvens. Many of the Firmicutes and Bacteroidetes isolates were identified as species that possess enzymes that ferment plant cell wall components, and the rest likely support these bacteria. The microbial communities that arose in these enrichment cultures had broad bacterial diversity. With over 30 % of the isolates not represented in culture, there are new opportunities to study genomic and metabolic capacities of these members of the complex intestinal microbiota.
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Affiliation(s)
- Cherie J Ziemer
- USDA, Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, IA 50010, USA.
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16
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Wu YR, He J. Characterization of anaerobic consortia coupled lignin depolymerization with biomethane generation. BIORESOURCE TECHNOLOGY 2013; 139:5-12. [PMID: 23639408 DOI: 10.1016/j.biortech.2013.03.103] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/16/2013] [Accepted: 03/17/2013] [Indexed: 06/02/2023]
Abstract
Two sediment-free microbial consortia (LI3 and LP3) were established to depolymerize lignin under anaerobic conditions. During depolymerizing high molecular weight lignin to low molecular weight molecules, the two cultures produced biomethane up to 151.7 and 113.0 mL g(-1) total lignin. Furthermore, LI3 and LP3 could also utilize the biomass - oil palm empty fruit bunch fiber (OPEFB) to produce 190.6 and 195.6 mL methaneg(-1) total lignin in OPEFB, and at the same time improve the bioavailability of lignocellulosic matters for further enzymatic hydrolysis. The microbial community analysis by denature gradient gel electrophoresis (DGGE) and the high-density 16S rDNA gene microarray (PhyloChip) exhibited that Methanomethylovorans sp. (LI3) and Methanoculleus sp. (LP3) were the main methanogens present, and phylum Firmicutes and Bacteroidetes were mainly involved in the lignin depolymerization. The established microbial consortia with both lignin depolymerization and biomethane production provide profound application on the environmental friendly pretreatment of lignocellulosic materials.
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Affiliation(s)
- Yi-Rui Wu
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore
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17
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Déjean G, Blanvillain-Baufumé S, Boulanger A, Darrasse A, de Bernonville TD, Girard AL, Carrére S, Jamet S, Zischek C, Lautier M, Solé M, Büttner D, Jacques MA, Lauber E, Arlat M. The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts. THE NEW PHYTOLOGIST 2013; 198:899-915. [PMID: 23442088 DOI: 10.1111/nph.12187] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature. Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts.
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Affiliation(s)
- Guillaume Déjean
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Servane Blanvillain-Baufumé
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Alice Boulanger
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Armelle Darrasse
- INRA, UMR 1345, Institut de Recherche en Horticulture et Semences (IRHS), 42 rue Georges Morel, 49071, Beaucouzé CEDEX 01, France
| | - Thomas Dugé de Bernonville
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Anne-Laure Girard
- INRA, UMR 1345, Institut de Recherche en Horticulture et Semences (IRHS), 42 rue Georges Morel, 49071, Beaucouzé CEDEX 01, France
| | - Sébastien Carrére
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Stevie Jamet
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Claudine Zischek
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Martine Lautier
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Magali Solé
- Institut für Biologie, Bereich Genetik, Martin-Luther-Universität Halle-Wittenberg, D-06099, Halle (Saale), Germany
| | - Daniela Büttner
- Institut für Biologie, Bereich Genetik, Martin-Luther-Universität Halle-Wittenberg, D-06099, Halle (Saale), Germany
| | - Marie-Agnès Jacques
- INRA, UMR 1345, Institut de Recherche en Horticulture et Semences (IRHS), 42 rue Georges Morel, 49071, Beaucouzé CEDEX 01, France
| | - Emmanuelle Lauber
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - Matthieu Arlat
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
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18
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Peng F, Peng P, Xu F, Sun RC. Fractional purification and bioconversion of hemicelluloses. Biotechnol Adv 2012; 30:879-903. [PMID: 22306329 DOI: 10.1016/j.biotechadv.2012.01.018] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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19
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Abstract
Bacteria that colonize the mammalian intestine collectively possess a far larger repertoire of degradative enzymes and metabolic capabilities than their hosts. Microbial fermentation of complex non-digestible dietary carbohydrates and host-derived glycans in the human intestine has important consequences for health. Certain dominant species, notably among the Bacteroidetes, are known to possess very large numbers of genes that encode carbohydrate active enzymes and can switch readily between different energy sources in the gut depending on availability. Nevertheless, more nutritionally specialized bacteria appear to play critical roles in the community by initiating the degradation of complex substrates such as plant cell walls, starch particles and mucin. Examples are emerging from the Firmicutes, Actinobacteria and Verrucomicrobium phyla, but more information is needed on these little studied groups. The impact of dietary carbohydrates, including prebiotics, on human health requires understanding of the complex relationship between diet composition, the gut microbiota and metabolic outputs.
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Affiliation(s)
- Harry J. Flint
- Rowett Institute of Nutrition and Health; University of Aberdeen; Bucksburn, Aberdeen UK,Correspondence to: Harry J. Flint,
| | - Karen P. Scott
- Rowett Institute of Nutrition and Health; University of Aberdeen; Bucksburn, Aberdeen UK
| | - Sylvia H. Duncan
- Rowett Institute of Nutrition and Health; University of Aberdeen; Bucksburn, Aberdeen UK
| | - Petra Louis
- Rowett Institute of Nutrition and Health; University of Aberdeen; Bucksburn, Aberdeen UK
| | - Evelyne Forano
- INRA; UR454 Microbiologie; Saint-Genès Champanelle, France
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20
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Wang Z, Jin Y, Wu H, Tian Z, Wu Y, Xie X. A novel, alkali-tolerant thermostable xylanase from Saccharomonospora viridis: direct gene cloning, expression and enzyme characterization. World J Microbiol Biotechnol 2012; 28:2741-8. [PMID: 22806200 DOI: 10.1007/s11274-012-1085-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 05/18/2012] [Indexed: 11/27/2022]
Abstract
A xylanase gene, designated Svixyn10A, was cloned from actinomycetes Saccharomonospora viridis and the gene product was characterized. Gene Svixyn10A contains 1,374 bp and encodes a polypeptide of 457 amino acids composed of a glycoside hydrolase family 10 catalytic domain with a putative signal peptide, a short Gly-rich linker and a family 2 carbohydrate-binding module (CBM). The deduced amino acid sequence of SviXyn10A shared the highest identity (57 %) with a hypothetical xylanase from Streptomyces lividans TK24 (ZP_05528201). A recombinant His-tagged xylanase, SviXyn10A was expressed in Escherichia coli BL21 and purified. The optimum pH and temperature for SviXyn10A is 8.0 and 60 °C. Compared with thermophilic and mesophilic counterparts, SviXyn10A was more active at high temperatures, retaining >63 % of its maximum activity at 65-70 °C and ~40 % even at 80 °C. It had broad pH adaptability (>35 % activity at pH 5.0-11.0) and alkali-tolerance (>70 % activity after incubation at pH 8.0-11.0 for 1 h at 37 °C), and was highly thermostable (>75 % activity after incubation at 70 °C for 3 h at pH 8.0). It may be the first alkali-tolerant thermostable xylanase reported from Saccharomonospora. These favorable properties make SviXyn10A a good candidate for application in pulp and paper industries.
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Affiliation(s)
- Ziyuan Wang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, 35 QingHua East Road, Beijing, 100083, People's Republic of China
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21
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Gong X, Gruniniger RJ, Forster RJ, Teather RM, McAllister TA. Biochemical analysis of a highly specific, pH stable xylanase gene identified from a bovine rumen-derived metagenomic library. Appl Microbiol Biotechnol 2012; 97:2423-31. [PMID: 22534823 DOI: 10.1007/s00253-012-4088-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/04/2012] [Accepted: 04/06/2012] [Indexed: 12/23/2022]
Abstract
A metagenomic library was generated using microbial DNA extracted from the rumen contents of a grass hay-fed dairy cow using a bacterial artificial chromosome-based vector system. Functional screening of the library identified a gene encoding a potent glycoside hydrolase, xyn10N18, localised within a xylanolytic gene cluster consisting of four open-reading frames (ORFs). The ORF, xyn10N18, encodes an endo-β-1,4-xylanase with a glycosyl hydrolase family 10 (GH10) catalytic domain, adopts a canonical α8/ß8-fold and possesses conserved catalytic glutamate residues typical of GH10 xylanases. Xyn10N18 exhibits optimal catalytic activity at 35 °C and pH 6.5 and was highly stable to pH changes retaining at least 85 % relative catalytic activity over a broad pH range (4.0-12.0). It retained 25 % of its relative activity at both low (4 °C) and high (55 °C) temperatures, however the stability of the enzyme rapidly decreased at temperatures of >40 °C. The specific activity of Xyn10N18 is enhanced by the divalent cations Mn(2+) and Co(2+) and is dramatically reduced by Hg(2+) and Cu(2+). Interestingly, EDTA had little effect on specific activity indicating that divalent cations do not function mechanistically. The enzyme was highly specific for xylan containing substrates and showed no catalytic activity against cellulose. Analysis of the hydrolysis products indicated that Xyn10N18 was an endoxylanase. Through a combination of structural modelling and in vitro enzyme characterisation this study provides an understanding of the mechanism and the substrate specificity of this enzyme serving as a starting point for directed evolution of Xyn10N18 and subsequent downstream use in industry.
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Affiliation(s)
- X Gong
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB, Canada
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22
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Dodd D, Mackie RI, Cann IKO. Xylan degradation, a metabolic property shared by rumen and human colonic Bacteroidetes. Mol Microbiol 2010; 79:292-304. [PMID: 21219452 DOI: 10.1111/j.1365-2958.2010.07473.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Microbial inhabitants of the bovine rumen fulfil the majority of the normal caloric requirements of the animal by fermenting lignocellulosic plant polysaccharides and releasing short chain fatty acids that are then metabolized by the host. This process also occurs within the human colon, although the fermentation products contribute less to the overall energy requirements of the host. Mounting evidence, however, indicates that the community structure of the distal gut microbiota is a critical factor that influences the inflammatory potential of the immune system thereby impacting the progression of inflammatory bowel diseases. Non-digestible dietary fibre derived from plant material is highly enriched in the lignocellulosic polysaccharides, cellulose and xylan. Members of the Bacteroidetes constitute a dominant phylum in both the human colonic microbiome and the rumen microbial ecosystem. In the current article, we review recent insights into the molecular mechanisms for xylan degradation by rumen and human commensal members of the Bacteroidetes phylum, and place this information in the context of the physiological and metabolic processes that occur within these complex microbial environments.
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Affiliation(s)
- Dylan Dodd
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
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