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Qian X, Jiang J, Yang B, Zhao J, Wang G, Tian P, Chen W. Psychobiotics Regulate Purine Metabolism to Influence Host Emotional Behavior. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:1561-1570. [PMID: 38197881 DOI: 10.1021/acs.jafc.3c06422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Purine metabolism plays a pivotal role in numerous biological processes with potential implications for brain function and emotional regulation. This study utilizes gene-edited probiotics and pseudo-germ-free mice to unravel this intricate interplay. Transcriptomic analysis identified a ribonucleoside-diphosphate reductase β chain (nrdB) as a pivotal gene in purine metabolism within Bifidobacterium breve CCFM1025. Comparative evaluation between the wild-type and nrdB mutant strains revealed CCFM1025's effective reduction of xanthine and xanthosine levels in the serum and brain of stressed mice. Concomitantly, it downregulated the expression of the adenosine receptor gene (Adora2b) and inhibited the overactivation of microglia. These findings emphasize the potential of psychobiotics in modulating emotional responses by regulating purine metabolites and adenosine receptors. This study sheds light on novel pathways that influence emotional well-being through gut microbiota interactions and purine metabolic processes.
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Affiliation(s)
- Xin Qian
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
| | - Jiahao Jiang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
| | - Bo Yang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
- (Yangzhou) Institute of Food Biotechnology, Jiangnan University, Yangzhou 225004, P. R. China
| | - Gang Wang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
- (Yangzhou) Institute of Food Biotechnology, Jiangnan University, Yangzhou 225004, P. R. China
| | - Peijun Tian
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
| | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122 P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China
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Zhang G, He M, Xiao L, Jiao Y, Han J, Li C, Miller MJ, Zhang L. Milk fat globule membrane protects Bifidobacterium longum ssp. infantis ATCC 15697 against bile stress by modifying global transcriptional responses. J Dairy Sci 2024; 107:91-104. [PMID: 37678788 DOI: 10.3168/jds.2023-23591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 07/17/2023] [Indexed: 09/09/2023]
Abstract
The milk fat globule membrane (MFGM) can protect probiotic bacteria from bile stress. However, its potential mechanism has not been reported. In this study, the viability, morphology and gene transcriptional response of Bifidobacterium longum ssp. infantis ATCC 15697 (BI_15697) stressed by bile salts with or without MFGM were investigated. It was shown that MFGM alleviated the reduction in BI_15697 population induced by 0.2% porcine bile stress and restored the population to the control levels. MFGM ameliorated the shrunken, fragmented appearance and irregular morphology of BI_15697 and maintained cell integrity disrupted by bile stress. RNA-sequencing results showed that MFGM increased transport of glucose and raffinose and decreased that of branched-chain amino acids (BCAA) in the presence of bile salts. MFGM stimulated the expression of genes involved in the synthesis of raffinose in galactose metabolism and the metabolism of BCAA, suggesting that MFGM stimulated the accumulation of raffinose and BCAA in the presence of bile. In addition, MFGM stimulated the expression of 2 bile efflux transporters under bile stress. Together, the multifactorial response helps BI_15697 excrete bile salts and maintain cellular integrity in response to bile stress. This study proposes a mechanism for the protection of BI_15697 against bile salt stress by MFGM, thereby providing a molecular basis for its application in incorporation of probiotics.
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Affiliation(s)
- Gongsheng Zhang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Mingxue He
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Lihong Xiao
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yuehua Jiao
- Center of Drug Safety Evaluation, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Jianchun Han
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China; Heilongjiang Green Food Science Research Institute, Harbin 150030, China.
| | - Chun Li
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China; Center of Drug Safety Evaluation, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Michael J Miller
- Department of Food Science and Human Nutrition, University of Illinois Urbana-Champaign, Urbana, IL 61801
| | - Lili Zhang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China.
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3
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Arzamasov AA, Nakajima A, Sakanaka M, Ojima MN, Katayama T, Rodionov DA, Osterman AL. Human Milk Oligosaccharide Utilization in Intestinal Bifidobacteria Is Governed by Global Transcriptional Regulator NagR. mSystems 2022; 7:e0034322. [PMID: 36094076 PMCID: PMC9599254 DOI: 10.1128/msystems.00343-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/23/2022] [Indexed: 12/24/2022] Open
Abstract
Bifidobacterium longum subsp. infantis is a prevalent beneficial bacterium that colonizes the human neonatal gut and is uniquely adapted to efficiently use human milk oligosaccharides (HMOs) as a carbon and energy source. Multiple studies have focused on characterizing the elements of HMO utilization machinery in B. longum subsp. infantis; however, the regulatory mechanisms governing the expression of these catabolic pathways remain poorly understood. A bioinformatic regulon reconstruction approach used in this study implicated NagR, a transcription factor from the ROK family, as a negative global regulator of gene clusters encoding lacto-N-biose/galacto-N-biose (LNB/GNB), lacto-N-tetraose (LNT), and lacto-N-neotetraose (LNnT) utilization pathways in B. longum subsp. infantis. This conjecture was corroborated by transcriptome profiling upon nagR genetic inactivation and experimental assessment of binding of recombinant NagR to predicted DNA operators. The latter approach also implicated N-acetylglucosamine (GlcNAc), a universal intermediate of LNT and LNnT catabolism, and its phosphorylated derivatives as plausible NagR transcriptional effectors. Reconstruction of NagR regulons in various Bifidobacterium lineages revealed multiple potential regulon expansion events, suggesting evolution from a local regulator of GlcNAc catabolism in ancestral bifidobacteria to a global regulator controlling the utilization of mixtures of GlcNAc-containing host glycans in B. longum subsp. infantis and Bifidobacterium bifidum. IMPORTANCE The predominance of bifidobacteria in the gut of breastfed infants is attributed to the ability of these bacteria to metabolize human milk oligosaccharides (HMOs). Thus, individual HMOs such as lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) are considered promising prebiotics that would stimulate the growth of bifidobacteria and confer multiple health benefits to preterm and malnourished children suffering from impaired (stunted) gut microbiota development. However, the rational selection of HMO-based prebiotics is hampered by the incomplete knowledge of regulatory mechanisms governing HMO utilization in target bifidobacteria. This study describes NagR-mediated transcriptional regulation of LNT and LNnT utilization in Bifidobacterium longum subsp. infantis. The elucidated regulatory network appears optimally adapted to simultaneous utilization of multiple HMOs, providing a rationale to add HMO mixtures (rather than individual components) to infant formulas. The study also provides insights into the evolutionary trajectories of complex regulatory networks controlling carbohydrate metabolism in bifidobacteria.
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Affiliation(s)
- Aleksandr A. Arzamasov
- Infectious and Inflammatory Diseases Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Aruto Nakajima
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | - Miriam N. Ojima
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Takane Katayama
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Dmitry A. Rodionov
- Infectious and Inflammatory Diseases Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Andrei L. Osterman
- Infectious and Inflammatory Diseases Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
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4
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The Gene Expression Profile Differs in Growth Phases of the Bifidobacterium Longum Culture. Microorganisms 2022; 10:microorganisms10081683. [PMID: 36014100 PMCID: PMC9415070 DOI: 10.3390/microorganisms10081683] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/21/2022] Open
Abstract
To date, transcriptomics have been widely and successfully employed to study gene expression in different cell growth phases of bacteria. Since bifidobacteria represent a major component of the gut microbiota of a healthy human that is associated with numerous health benefits for the host, it is important to study them using transcriptomics. In this study, we applied the RNA-Seq technique to study global gene expression of B. longum at different growth phases in order to better understand the response of bifidobacterial cells to the specific conditions of the human gut. We have shown that in the lag phase, ABC transporters, whose function may be linked to active substrate utilization, are increasingly expressed due to preparation for cell division. In the exponential phase, the functions of activated genes include synthesis of amino acids (alanine and arginine), energy metabolism (glycolysis/gluconeogenesis and nitrogen metabolism), and translation, all of which promote active cell division, leading to exponential growth of the culture. In the stationary phase, we observed a decrease in the expression of genes involved in the control of the rate of cell division and an increase in the expression of genes involved in defense-related metabolic pathways. We surmise that the latter ensures cell survival in the nutrient-deprived conditions of the stationary growth phase.
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5
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Maximum depth sequencing reveals an ON/OFF replication slippage switch and apparent in vivo selection for bifidobacterial pilus expression. Sci Rep 2022; 12:9576. [PMID: 35688912 PMCID: PMC9187656 DOI: 10.1038/s41598-022-13668-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 05/16/2022] [Indexed: 11/09/2022] Open
Abstract
The human gut microbiome, of which the genus Bifidobacterium is a prevalent and abundant member, is thought to sustain and enhance human health. Several surface-exposed structures, including so-called sortase-dependent pili, represent important bifidobacterial gut colonization factors. Here we show that expression of two sortase-dependent pilus clusters of the prototype Bifidobacterium breve UCC2003 depends on replication slippage at an intragenic G-tract, equivalents of which are present in various members of the Bifidobacterium genus. The nature and extent of this slippage is modulated by the host environment. Involvement of such sortase-dependent pilus clusters in microbe-host interactions, including bacterial attachment to the gut epithelial cells, has been shown previously and is corroborated here for one case. Using a Maximum Depth Sequencing strategy aimed at excluding PCR and sequencing errors introduced by DNA polymerase reagents, specific G-tract sequences in B. breve UCC2003 reveal a range of G-tract lengths whose plasticity within the population is functionally utilized. Interestingly, replication slippage is shown to be modulated under in vivo conditions in a murine model. This in vivo modulation causes an enrichment of a G-tract length which appears to allow biosynthesis of these sortase-dependent pili. This work provides the first example of productive replication slippage influenced by in vivo conditions. It highlights the potential for microdiversity generation in “beneficial” gut commensals.
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6
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Laursen MF, Sakanaka M, von Burg N, Mörbe U, Andersen D, Moll JM, Pekmez CT, Rivollier A, Michaelsen KF, Mølgaard C, Lind MV, Dragsted LO, Katayama T, Frandsen HL, Vinggaard AM, Bahl MI, Brix S, Agace W, Licht TR, Roager HM. Bifidobacterium species associated with breastfeeding produce aromatic lactic acids in the infant gut. Nat Microbiol 2021; 6:1367-1382. [PMID: 34675385 PMCID: PMC8556157 DOI: 10.1038/s41564-021-00970-4] [Citation(s) in RCA: 184] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022]
Abstract
Breastfeeding profoundly shapes the infant gut microbiota, which is critical for early life immune development, and the gut microbiota can impact host physiology in various ways, such as through the production of metabolites. However, few breastmilk-dependent microbial metabolites mediating host-microbiota interactions are currently known. Here, we demonstrate that breastmilk-promoted Bifidobacterium species convert aromatic amino acids (tryptophan, phenylalanine and tyrosine) into their respective aromatic lactic acids (indolelactic acid, phenyllactic acid and 4-hydroxyphenyllactic acid) via a previously unrecognized aromatic lactate dehydrogenase (ALDH). The ability of Bifidobacterium species to convert aromatic amino acids to their lactic acid derivatives was confirmed using monocolonized mice. Longitudinal profiling of the faecal microbiota composition and metabolome of Danish infants (n = 25), from birth until 6 months of age, showed that faecal concentrations of aromatic lactic acids are correlated positively with the abundance of human milk oligosaccharide-degrading Bifidobacterium species containing the ALDH, including Bifidobacterium longum, B. breve and B. bifidum. We further demonstrate that faecal concentrations of Bifidobacterium-derived indolelactic acid are associated with the capacity of these samples to activate in vitro the aryl hydrocarbon receptor (AhR), a receptor important for controlling intestinal homoeostasis and immune responses. Finally, we show that indolelactic acid modulates ex vivo immune responses of human CD4+ T cells and monocytes in a dose-dependent manner by acting as an agonist of both the AhR and hydroxycarboxylic acid receptor 3 (HCA3). Our findings reveal that breastmilk-promoted Bifidobacterium species produce aromatic lactic acids in the gut of infants and suggest that these microbial metabolites may impact immune function in early life.
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Affiliation(s)
- Martin F Laursen
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Mikiyasu Sakanaka
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
- Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, Ishikawa, Japan
| | - Nicole von Burg
- Mucosal Immunology Group, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Urs Mörbe
- Mucosal Immunology Group, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Daniel Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Janne Marie Moll
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ceyda T Pekmez
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark
| | - Aymeric Rivollier
- Mucosal Immunology Group, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Kim F Michaelsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark
| | - Christian Mølgaard
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark
| | - Mads Vendelbo Lind
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark
| | - Lars O Dragsted
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark
| | - Takane Katayama
- Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, Ishikawa, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Henrik L Frandsen
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Martin I Bahl
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Susanne Brix
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - William Agace
- Mucosal Immunology Group, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
- Immunology Section, BMC D14, Department of Experimental Medicine, Lund University, Lund, Sweden
| | - Tine R Licht
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark.
| | - Henrik M Roager
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark.
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark.
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7
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Park J, Wang HH. Systematic dissection of σ 70 sequence diversity and function in bacteria. Cell Rep 2021; 36:109590. [PMID: 34433066 PMCID: PMC8716302 DOI: 10.1016/j.celrep.2021.109590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 04/19/2021] [Accepted: 08/02/2021] [Indexed: 10/29/2022] Open
Abstract
Primary σ70 factors are key conserved bacterial regulatory proteins that interact with regulatory DNA to control gene expression. It is, however, poorly understood whether σ70 sequence diversity in different bacteria reflects functional differences. Here, we employ comparative and functional genomics to explore the sequence and function relationship of primary σ70. Using multiplex automated genome engineering and deep sequencing (MAGE-seq), we generate a saturation mutagenesis library and high-resolution fitness map of E. coli σ70 in domains 2-4. Mapping natural σ70 sequence diversity to the E. coli σ70 fitness landscape reveals significant predicted fitness deficits across σ70 orthologs. Interestingly, these predicted deficits are larger than observed fitness changes for 15 σ70 orthologs introduced into E. coli. Finally, we use a multiplexed transcriptional reporter assay and RNA sequencing (RNA-seq) to explore functional differences of several σ70 orthologs. This work provides an in-depth analysis of σ70 sequence and function to improve efforts to understand the evolution and engineering potential of this global regulator.
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Affiliation(s)
- Jimin Park
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA; Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University Irving Medical Center, New York, NY, USA.
| | - Harris H Wang
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.
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8
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Dineen RL, Penno C, Kelleher P, Bourin MJB, O'Connell‐Motherway M, van Sinderen D. Molecular analysis of the replication functions of the bifidobacterial conjugative megaplasmid pMP7017. Microb Biotechnol 2021; 14:1494-1511. [PMID: 33939264 PMCID: PMC8313286 DOI: 10.1111/1751-7915.13810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 03/22/2021] [Indexed: 11/29/2022] Open
Abstract
pMP7017 is a conjugative megaplasmid isolated from the gut commensal Bifidobacterium breve JCM7017 and was shown to encode two putative replicases, designated here as RepA and RepB. In the current work, RepB was identified as the pMP7017 replicative initiator, as the repB gene, and its surrounding region was shown to be sufficient to allow autonomous replication in two bifidobacterial species, B. breve and Bifidobacterium longum subsp. longum. RepB was shown to bind to repeat sequence downstream of its coding sequence and this region was determined to be essential for efficient replication. Based on our results, we hypothesize that pMP7017 is an iteron-regulated plasmid (IRP) under strict auto-regulatory control. Recombinantly produced and purified RepB was determined to exist as a dimer in solution, differing from replicases of other IRPs, which exist as a mix of dimers and monomers. Furthermore, a stable low-copy Bifidobacterium-E. coli shuttle vector, pRD1.3, was created which can be employed for cloning and expression of large genes, as was demonstrated by the cloning and heterologous expression of the 5.1 kb apuB gene encoding the extracellular amylopullulanase from B. breve UCC2003 into B. longum subsp. longum NCIMB8809.
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Affiliation(s)
- Rebecca L. Dineen
- APC Microbiome IrelandUniversity College CorkWestern RoadCorkIreland
- School of MicrobiologyUniversity College CorkWestern RoadCorkIreland
| | - Christophe Penno
- CNRS UMR 6553 EcoBioUniversite de Rennes 1Campus de Beaulieu, Bat. 14ARennes cedex35042France
| | - Philip Kelleher
- APC Microbiome IrelandUniversity College CorkWestern RoadCorkIreland
- School of MicrobiologyUniversity College CorkWestern RoadCorkIreland
| | - Maxence J. B. Bourin
- APC Microbiome IrelandUniversity College CorkWestern RoadCorkIreland
- School of MicrobiologyUniversity College CorkWestern RoadCorkIreland
| | | | - Douwe van Sinderen
- APC Microbiome IrelandUniversity College CorkWestern RoadCorkIreland
- School of MicrobiologyUniversity College CorkWestern RoadCorkIreland
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9
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Hoedt EC, Bottacini F, Cash N, Bongers RS, van Limpt K, Ben Amor K, Knol J, MacSharry J, van Sinderen D. Broad Purpose Vector for Site-Directed Insertional Mutagenesis in Bifidobacterium breve. Front Microbiol 2021; 12:636822. [PMID: 33833740 PMCID: PMC8021953 DOI: 10.3389/fmicb.2021.636822] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/02/2021] [Indexed: 11/28/2022] Open
Abstract
Members of the genus Bifidobacterium are notoriously recalcitrant to genetic manipulation due to their extensive and variable repertoire of Restriction-Modification (R-M) systems. Non-replicating plasmids are currently employed to achieve insertional mutagenesis in Bifidobacterium. One of the limitations of using such insertion vectors is the presence within their sequence of various restriction sites, making them sensitive to the activity of endogenous restriction endonucleases encoded by the target strain. For this reason, vectors have been developed with the aim of methylating and protecting the vector using a methylase-positive Escherichia coli strain, in some cases containing a cloned bifidobacterial methylase. Here, we present a mutagenesis approach based on a modified and synthetically produced version of the suicide vector pORI28 (named pFREM28), where all known restriction sites targeted by Bifidobacterium breve R-M systems were removed by base substitution (thus preserving the codon usage). After validating the integrity of the erythromycin marker, the vector was successfully employed to target an α-galactosidase gene responsible for raffinose metabolism, an alcohol dehydrogenase gene responsible for mannitol utilization and a gene encoding a priming glycosyltransferase responsible for exopolysaccharides (EPS) production in B. breve. The advantage of using this modified approach is the reduction of the amount of time, effort and resources required to generate site-directed mutants in B. breve and a similar approach may be employed to target other (bifido)bacterial species.
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Affiliation(s)
- Emily C Hoedt
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,NHMRC Centre of Research Excellence in Digestive Health, School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia
| | - Francesca Bottacini
- NHMRC Centre of Research Excellence in Digestive Health, School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia.,Department of Biological Sciences, Munster Technological University, Cork, Ireland
| | - Nora Cash
- NHMRC Centre of Research Excellence in Digestive Health, School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia
| | | | | | | | - Jan Knol
- Danone Nutricia Research, Utrecht, Netherlands.,Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - John MacSharry
- NHMRC Centre of Research Excellence in Digestive Health, School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia.,School of Microbiology, University College Cork, Cork, Ireland.,School of Medicine, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- NHMRC Centre of Research Excellence in Digestive Health, School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia.,School of Microbiology, University College Cork, Cork, Ireland
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10
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A Resource for Cloning and Expression Vectors Designed for Bifidobacteria: Overview of Available Tools and Biotechnological Applications. Methods Mol Biol 2021. [PMID: 33649956 DOI: 10.1007/978-1-0716-1274-3_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2023]
Abstract
Bifidobacteria represent an important group of (mostly) commensal microorganisms, which have enjoyed increasing scientific and industrial attention due to their purported health-promoting attributes. For the latter reason, several species have been granted "generally recognized as safe" (GRAS) and "qualified presumption of safety" (QPS) status by the Food and Drugs Administration (FDA) and European Food Safety Authority (EFSA) organizations. Increasing scientific evidence supports their potential as oral delivery vectors to produce bioactive and therapeutic molecules at intestinal level. In order to achieve an efficient utilization of bifidobacterial strains as health-promoting (food) ingredients, it is necessary to provide evidence on the molecular mechanisms behind their purported beneficial and probiotic traits, and precise mechanisms of interaction with their human (or other mammalian) host. In this context, developing appropriate molecular tools to generate and investigate recombinant strains is necessary. While bifidobacteria have long remained recalcitrant to genetic manipulation, a wide array of Bifidobacterium-specific replicating vectors and genetic modification procedures have been described in literature. The current chapter intends to provide an updated overview on the vectors used to genetically modify and manipulate bifidobacteria, including their general characteristics, reviewing examples of their use to successfully generate recombinant bifidobacterial strains for specific purposes, and providing a general workflow and cautions to design and conduct heterologous expression in bifidobacteria. Knowledge gaps and fields of research that may help to widen the molecular toolbox to improve the functional and technological potential of bifidobacteria are also discussed.
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11
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Kozakai T, Shimofusa Y, Nomura I, Suzuki T. Construction of a reporter system for bifidobacteria using chloramphenicol acetyltransferase and its application for evaluation of promoters and terminators. BIOSCIENCE OF MICROBIOTA FOOD AND HEALTH 2021; 40:115-122. [PMID: 33996368 PMCID: PMC8099631 DOI: 10.12938/bmfh.2020-070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/30/2020] [Indexed: 11/23/2022]
Abstract
A reporter assay system is an essential tool for investigating gene expression
mechanisms. In the case of bifidobacteria, several convenient and sensitive reporter
systems have been developed. Here, we developed a new reporter system for bifidobacteria
using the chloramphenicol acetyltransferase gene (cat) from
Staphylococcus aureus. This enzyme stoichiometrically produced free
CoA-SH, which was analyzed quantitatively with Ellman’s test using 2-nitrobenzoic acid
(DTNB). The 2-nitro-5-thiobenzoate (TNB2-) produced showed a strong yellowish
color with maximum absorbance at 412 nm. We also constructed a new pBCMAT plasmid series
for CAT assays in bifidobacteria to evaluate promoters and terminators. Analyses using
promoters from Bifidobacterium longum NCC2705 indicated that the CAT
assay using these promoters is quantitative, has a wide measurement range, and is stable.
In addition, this assay was useful for several bifidobacterial species, including
B. longum, Bifidobacterium breve, and
Bifidobacterium adolescentis. Compared with evoglow-Bs2, a fluorescent
protein used under anaerobic conditions, the CAT assay showed about 0.25% background
activity. In analyses using this CAT assay, we identified 11 promoters and 12 terminators
of B. longum NCC2705. The genes encoding ribosomal proteins, elongation
factors, and transfer RNAs possessed strong promoters, and terminators that include strong
stem-loops and poly-U tails structures tended to show high activities. Although the
abovementioned promoters made stronger contributions to expression activities than the
terminators, the maximum fold difference in the activities among the tested terminators
was approximately 17-fold. Modification of the -10 box and 5’-UTR in the
promoters and the structure around the stem-loop in the terminators affected expression
levels. These results suggest that the CAT assay is useful for various analyses of
bifidobacterial gene expression.
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Affiliation(s)
- Tomoya Kozakai
- United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
| | - Yoko Shimofusa
- Graduate School of Natural Science and Technology, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
| | - Izumi Nomura
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
| | - Tohru Suzuki
- United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan.,Graduate School of Natural Science and Technology, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan.,Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
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12
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Engineer probiotic bifidobacteria for food and biomedical applications - Current status and future prospective. Biotechnol Adv 2020; 45:107654. [DOI: 10.1016/j.biotechadv.2020.107654] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/14/2020] [Accepted: 11/01/2020] [Indexed: 12/15/2022]
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13
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Veselovsky VA, Dyachkova MS, Menyaylo EA, Polyaeva PS, Olekhnovich EI, Shitikov EA, Bespiatykh DA, Semashko TA, Kasianov AS, Ilina EN, Danilenko VN, Klimina KM. Gene Networks Underlying the Resistance of Bifidobacterium longum to Inflammatory Factors. Front Immunol 2020; 11:595877. [PMID: 33304352 PMCID: PMC7701253 DOI: 10.3389/fimmu.2020.595877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/20/2020] [Indexed: 01/14/2023] Open
Abstract
As permanent residents of the normal gut microbiota, bifidobacteria have evolved to adapt to the host’s immune response whose priority is to eliminate pathogenic agents. The mechanisms that ensure the survival of commensals during inflammation and maintain the stability of the core component of the normal gut microbiota in such conditions remain poorly understood. We propose a new in vitro approach to study the mechanisms of resistance to immune response factors based on high-throughput sequencing followed by transcriptome analysis. This approach allowed us to detect differentially expressed genes associated with inflammation. In this study, we demonstrated that the presence of the pro-inflammatory cytokines IL-6 and TNFα to the growth medium of the B. longum subsp. longum GT15 strain changes the latter’s growth rate insignificantly while affecting the expression of certain genes. We identified these genes and performed a COG and a KEGG pathway enrichment analysis. Using phylogenetic profiling we predicted the operons of genes whose expression was triggered by the cytokines TNFα and IL-6 in vitro. By mapping the transcription start points, we experimentally validated the predicted operons. Thus, in this study, we predicted the genes involved in a putative signaling pathway underlying the mechanisms of resistance to inflammatory factors in bifidobacteria. Since bifidobacteria are a major component of the human intestinal microbiota exhibiting pronounced anti-inflammatory properties, this study is of great practical and scientific relevance.
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Affiliation(s)
- Vladimir A Veselovsky
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Marina S Dyachkova
- Department of Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia
| | - Egor A Menyaylo
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Polina S Polyaeva
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Evgenii I Olekhnovich
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Egor A Shitikov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Dmitry A Bespiatykh
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Tatiana A Semashko
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Artem S Kasianov
- Department of Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia.,Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia.,Laboratory of Plant Genomics, The Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow, Russia
| | - Elena N Ilina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Valeriy N Danilenko
- Department of Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia.,Faculty of Ecology, International Institute for Strategic Development of Sectoral Economics Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
| | - Ksenia M Klimina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia.,Department of Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia
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14
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Application of Recombinase-Based In Vivo Expression Technology to Bifidobacterium longum subsp. longum for Identification of Genes Induced in the Gastrointestinal Tract of Mice. Microorganisms 2020; 8:microorganisms8030410. [PMID: 32183191 PMCID: PMC7143038 DOI: 10.3390/microorganisms8030410] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/07/2020] [Accepted: 03/10/2020] [Indexed: 12/13/2022] Open
Abstract
Bifidobacteria are one of the major components in human gut microbiota and well-known as beneficial microbes. However, clarification of commensal mechanisms of bifidobacteria in the intestines is still ongoing, especially in the presence of the gut microbiota. Here, we applied recombinase-based in vivo expression technology (R-IVET) using the bacteriophage P1 Cre/loxP system to Bifidobacterium longum subsp. longum 105-A (B. longum 105-A) to identify genes that are specifically expressed in the gastrointestinal tract of conventionally raised mice. Oral administration of the genomic DNA library of B. longum 105-A to conventionally raised mice resulted in the identification of 73 in vivo-induced genes. Four out of seven tested genes were verified in vivo-specific induction at least in the cecum by quantitative reverse transcription PCR. Although there is still room for improvement of the system, our findings can contribute to expanding our understanding of the commensal behavior of B. longum in the gut ecosystem.
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15
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Structure of a Core Promoter in Bifidobacterium longum NCC2705. J Bacteriol 2020; 202:JB.00540-19. [PMID: 31964699 DOI: 10.1128/jb.00540-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/14/2020] [Indexed: 01/04/2023] Open
Abstract
Bacterial promoters consist of core sequence motifs termed -35 and -10 boxes. The consensus motifs are TTGACA and TATAAT, respectively, which were identified from leading investigations on Escherichia coli However, the consensus sequences are not likely to fit genetically divergent bacteria. The sigma factor of the genus Bifidobacterium has a characteristic polar domain in the N terminus, suggesting the possibility of specific promoter recognition. We reevaluated the structure of Bifidobacterium longum NCC2705 promoters and compared them to other bacteria. Transcriptional start sites (TSSs) of the B. longum NCC2705 strain were identified using transcriptome sequencing (RNA-Seq) analysis to extract promoter regions. Conserved motifs of a bifidobacterial promoter were determined using regions upstream of TSSs and a hidden Markov model. As a result, consensus motifs of the -35 and -10 boxes were TTGTGC and TACAAT, respectively. To assess each base of both motifs, we constructed 37 plasmids based on pKO403-TPCTcon, including the hup promoter connected with a chloramphenicol acetyltransferase as a reporter gene. This reporter assay showed two optimal motifs of the -35 and -10 boxes, namely, TTGNNN and TANNNT, respectively. We further analyzed spacer lengths between the -35 and -10 boxes via a bioinformatics approach. The spacer lengths predominant in bacteria have been generally reported to be approximately 17 bp. In contrast, the predominant spacer lengths in the genus Bifidobacterium and related species were 11 bp, in addition to 17 bp. A reporter assay to assess the spacer lengths indicated that the 11-bp spacer length produced unusually high activity.IMPORTANCE The structures of sigma factors vary among bacterial strains, indicating that recognition rules may also vary. Therefore, we investigated the promoter structure of Bifidobacterium longum NCC2705 using a bioinformatics approach and wet analyses. The most frequent and optimal motifs were similar to other bacterial consensus motifs. The optimal spacer length between the two boxes was reported to be 17 bp. It is widely applied to a bioinformatics approach for other bacteria. Unexpectedly, conserved spacer lengths were 11 bp as well as 17 bp in the genus Bifidobacterium Moreover, the sigma factor of the genus Bifidobacterium has a characteristic domain in the N terminus which may contribute to the additional functions. Hence, it would be valuable to reevaluate the promoter in other organisms.
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16
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Senizza A, Callegari ML, Senizza B, Minuti A, Rocchetti G, Morelli L, Patrone V. Effects of Linoleic Acid on Gut-Derived Bifidobacterium breve DSM 20213: A Transcriptomic Approach. Microorganisms 2019; 7:microorganisms7120710. [PMID: 31861103 PMCID: PMC6955684 DOI: 10.3390/microorganisms7120710] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/12/2019] [Accepted: 12/16/2019] [Indexed: 02/08/2023] Open
Abstract
Bacterial production of conjugated linoleic acid (CLA) has recently received great attention because of the potential health benefits of this fatty acid. Linoleic acid (LA) can be converted to CLA by several microorganisms, including bifidobacteria, possibly as a detoxification mechanism to avoid the growth inhibition effect of LA. In the present in vitro study, we investigated the gene expression landscape of the intestinal strain Bifidobacterium breve DSM 20213 when exposed to LA. Transcriptomic analysis using RNA-seq revealed that LA induced a multifactorial stress response in the test strain, including upregulation of genes involved in iron uptake and downregulation of genes involved in sugar and oligopeptide transport. We also observed reduced transcription of genes involved in membrane and pili biosynthesis. The upregulation of iron uptake was not related to any putative ability of LA to chelate Fe2+, but was somewhat linked to stress response. Furthermore, we demonstrated that LA increased reactive oxygen species (ROS) production in bacterial cells, activating an oxidative stress response. This response was proved by thioredoxin reductase transcription, and was primarily evident among bacteria cultured in the absence of cysteine. This is the first report of the potential mechanisms involved in bacterial LA transport and stress response in B. breve.
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Affiliation(s)
- Alice Senizza
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
| | - Maria Luisa Callegari
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
- Biotechnology Research Centre (CRB), via Milano 24, 26100 Cremona, Italy
| | - Biancamaria Senizza
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
| | - Andrea Minuti
- Department of Animal Science, Food and Nutrition (DiANA), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy;
- Nutrigenomics and Proteomics Research Center (PRONUTRIGEN), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Gabriele Rocchetti
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
| | - Lorenzo Morelli
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
- Biotechnology Research Centre (CRB), via Milano 24, 26100 Cremona, Italy
| | - Vania Patrone
- Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy; (A.S.); (M.L.C.); (B.S.); (G.R.); (L.M.)
- Nutrigenomics and Proteomics Research Center (PRONUTRIGEN), Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy
- Correspondence: ; Tel.: +39-0523-599247
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17
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Lanigan N, Kelly E, Arzamasov AA, Stanton C, Rodionov DA, van Sinderen D. Transcriptional control of central carbon metabolic flux in Bifidobacteria by two functionally similar, yet distinct LacI-type regulators. Sci Rep 2019; 9:17851. [PMID: 31780796 PMCID: PMC6882875 DOI: 10.1038/s41598-019-54229-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022] Open
Abstract
Bifidobacteria resident in the gastrointestinal tract (GIT) are subject to constantly changing environmental conditions, which require rapid adjustments in gene expression. Here, we show that two predicted LacI-type transcription factors (TFs), designated AraQ and MalR1, are involved in regulating the central, carbohydrate-associated metabolic pathway (the so-called phosphoketolase pathway or bifid shunt) of the gut commensal Bifidobacterium breve UCC2003. These TFs appear to not only control transcription of genes involved in the bifid shunt and each other, but also seem to commonly and directly affect transcription of other TF-encoding genes, as well as genes related to uptake and metabolism of various carbohydrates. This complex and interactive network of AraQ/MalR1-mediated gene regulation provides previously unknown insights into the governance of carbon metabolism in bifidobacteria.
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Affiliation(s)
- Noreen Lanigan
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland
| | - Emer Kelly
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland
| | - Aleksandr A Arzamasov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States.,A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Dmitry A Rodionov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States.,A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland.
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18
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Metabolism of the predominant human milk oligosaccharide fucosyllactose by an infant gut commensal. Sci Rep 2019; 9:15427. [PMID: 31659215 PMCID: PMC6817895 DOI: 10.1038/s41598-019-51901-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/09/2019] [Indexed: 12/22/2022] Open
Abstract
A number of bifidobacterial species are found at a particularly high prevalence and abundance in faecal samples of healthy breastfed infants, a phenomenon that is believed to be, at least partially, due to the ability of bifidobacteria to metabolize Human Milk Oligosaccharides (HMOs). In the current study, we isolated a novel strain of Bifidobacterium kashiwanohense, named APCKJ1, from the faeces of a four-week old breastfed infant, based on the ability of the strain to utilise the HMO component fucosyllactose. We then determined the full genome sequence of this strain, and employed the generated data to analyze fucosyllactose metabolism in B. kashiwanohense APCKJ1. Transcriptomic and growth analyses, combined with metabolite analysis, in vitro hydrolysis assays and heterologous expression, allowed us to elucidate the pathway for fucosyllactose metabolism in B. kashiwanohense APCKJ1. Homologs of the key genes for this metabolic pathway were identified in particular in infant-derived members of the Bifdobacterium genus, revealing the apparent niche-specific nature of this pathway, and allowing a broad perspective on bifidobacterial fucosyllactose and L-fucose metabolism.
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19
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Dissecting the Evolutionary Development of the Species Bifidobacterium animalis through Comparative Genomics Analyses. Appl Environ Microbiol 2019; 85:AEM.02806-18. [PMID: 30709821 DOI: 10.1128/aem.02806-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/28/2019] [Indexed: 12/20/2022] Open
Abstract
Bifidobacteria are members of the gut microbiota of animals, including mammals, birds, and social insects. In this study, we analyzed and determined the pangenome of Bifidobacterium animalis species, encompassing B. animalis subsp. animalis and the B. animalis subsp. lactis taxon, which is one of the most intensely exploited probiotic bifidobacterial species. In order to reveal differences within the B. animalis species, detailed comparative genomics and phylogenomics analyses were performed, indicating that these two subspecies recently arose through divergent evolutionary events. A subspecies-specific core genome was identified for both B. animalis subspecies, revealing the existence of subspecies-defining genes involved in carbohydrate metabolism. Notably, these in silico analyses coupled with carbohydrate profiling assays suggest genetic adaptations toward a distinct glycan milieu for each member of the B. animalis subspecies, resulting in a divergent evolutionary development of the two subspecies.IMPORTANCE The majority of characterized B. animalis strains have been isolated from human fecal samples. In order to explore genome variability within this species, we isolated 15 novel strains from the gastrointestinal tracts of different animals, including mammals and birds. The present study allowed us to reconstruct the pangenome of this taxon, including the genome contents of 56 B. animalis strains. Through careful assessment of subspecies-specific core genes of the B. animalis subsp. animalis/lactis taxon, we identified genes encoding enzymes involved in carbohydrate transport and metabolism, while unveiling specific gene acquisition and loss events that caused the evolutionary emergence of these two subspecies.
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20
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Bifidobacterium breve UCC2003 Employs Multiple Transcriptional Regulators To Control Metabolism of Particular Human Milk Oligosaccharides. Appl Environ Microbiol 2018; 84:AEM.02774-17. [PMID: 29500268 DOI: 10.1128/aem.02774-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/23/2018] [Indexed: 11/20/2022] Open
Abstract
Bifidobacterial carbohydrate metabolism has been studied in considerable detail for a variety of both plant- and human-derived glycans, particularly involving the bifidobacterial prototype strain Bifidobacterium breve UCC2003. We recently elucidated the metabolic pathways by which the human milk oligosaccharide (HMO) constituents lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT) and lacto-N-biose (LNB) are utilized by B. breve UCC2003. However, to date, no work has been carried out on the regulatory mechanisms that control the expression of the genetic loci involved in these HMO metabolic pathways. In this study, we describe the characterization of three transcriptional regulators and the corresponding operator and associated (inducible) promoter sequences, with the latter governing the transcription of the genetic elements involved in LN(n)T/LNB metabolism. The activity of these regulators is dependent on the release of specific monosaccharides, which are believed to act as allosteric effectors and which are derived from the corresponding HMOs targeted by the particular locus.IMPORTANCE Human milk oligosaccharides (HMOs) are a key factor in the development of the breastfed-infant microbiota. They function as prebiotics, selecting for a specific range of microbes, including a number of infant-associated species of bifidobacteria, which are thought to provide a range of health benefits to the infant host. While much research has been carried out on elucidating the mechanisms of HMO metabolism in infant-associated bifidobacteria, to date there is very little understanding of the transcriptional regulation of these pathways. This study reveals a multicomponent transcriptional regulation system that controls the recently identified pathways of HMO metabolism in the infant-associated Bifidobacterium breve prototype strain UCC2003. This not only provides insight into the regulatory mechanisms present in other infant-associated bifidobacteria but also provides an example of a network of sequential steps regulating microbial carbohydrate metabolism.
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