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Qiu S, Huang Y, Liang S, Zeng H, Yang A. Systematic elucidation of independently modulated genes in Lactiplantibacillus plantarum reveals a trade-off between secondary and primary metabolism. Microb Biotechnol 2024; 17:e14425. [PMID: 38393514 PMCID: PMC10886434 DOI: 10.1111/1751-7915.14425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/02/2024] [Indexed: 02/25/2024] Open
Abstract
Lactiplantibacillus plantarum is a probiotic bacterium widely used in food and health industries, but its gene regulatory information is limited in existing databases, which impedes the research of its physiology and its applications. To obtain a better understanding of the transcriptional regulatory network of L. plantarum, independent component analysis of its transcriptomes was used to derive 45 sets of independently modulated genes (iModulons). Those iModulons were annotated for associated transcription factors and functional pathways, and active iModulons in response to different growth conditions were identified and characterized in detail. Eventually, the analysis of iModulon activities reveals a trade-off between regulatory activities of secondary and primary metabolism in L. plantarum.
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Affiliation(s)
- Sizhe Qiu
- Department of Engineering ScienceUniversity of OxfordOxfordUK
- School of Food and HealthBeijing Technology and Business UniversityBeijingChina
| | - Yidi Huang
- School of Computer Science and EngineeringBeihang UniversityBeijingChina
| | - Shishun Liang
- Department of Life ScienceImperial College LondonLondonUK
| | - Hong Zeng
- School of Food and HealthBeijing Technology and Business UniversityBeijingChina
| | - Aidong Yang
- Department of Engineering ScienceUniversity of OxfordOxfordUK
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2
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Karlsen ST, Rau MH, Sánchez BJ, Jensen K, Zeidan AA. From genotype to phenotype: computational approaches for inferring microbial traits relevant to the food industry. FEMS Microbiol Rev 2023; 47:fuad030. [PMID: 37286882 PMCID: PMC10337747 DOI: 10.1093/femsre/fuad030] [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: 02/28/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/09/2023] Open
Abstract
When selecting microbial strains for the production of fermented foods, various microbial phenotypes need to be taken into account to achieve target product characteristics, such as biosafety, flavor, texture, and health-promoting effects. Through continuous advances in sequencing technologies, microbial whole-genome sequences of increasing quality can now be obtained both cheaper and faster, which increases the relevance of genome-based characterization of microbial phenotypes. Prediction of microbial phenotypes from genome sequences makes it possible to quickly screen large strain collections in silico to identify candidates with desirable traits. Several microbial phenotypes relevant to the production of fermented foods can be predicted using knowledge-based approaches, leveraging our existing understanding of the genetic and molecular mechanisms underlying those phenotypes. In the absence of this knowledge, data-driven approaches can be applied to estimate genotype-phenotype relationships based on large experimental datasets. Here, we review computational methods that implement knowledge- and data-driven approaches for phenotype prediction, as well as methods that combine elements from both approaches. Furthermore, we provide examples of how these methods have been applied in industrial biotechnology, with special focus on the fermented food industry.
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Affiliation(s)
- Signe T Karlsen
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Martin H Rau
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Benjamín J Sánchez
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Kristian Jensen
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Ahmad A Zeidan
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
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3
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Wa Y, Zhang C, Sun G, Qu H, Chen D, Huang Y, Gu R. Effect of amino acids on free exopolysaccharide biosynthesis by Streptococcus thermophilus 937 in chemically defined medium. J Dairy Sci 2022; 105:6460-6468. [PMID: 35691747 DOI: 10.3168/jds.2022-21814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/05/2022] [Indexed: 11/19/2022]
Abstract
Free exopolysaccharide (f-EPS) produced by Streptococcus thermophilus improves the texture and functionality of fermented dairy foods. Our previous study showed a major improvement in f-EPS production of Strep. thermophilus 937 by increasing the concentrations of histidine, isoleucine, and glutamate to 15 mM in an optimized chemically defined medium. The aim of this study was to elucidate the effect of His, Ile, and Glu on the growth, f-EPS biosynthesis pathway, and carbohydrate metabolism profiles of Strep. thermophilus 937. The growth kinetics; transcript levels of key genes in the EPS biosynthesis pathway; enzyme activity involved in sugar nucleotide synthesis; concentrations of lactic acid, lactose, and galactose; and extracellular and intracellular pH were analyzed in chemically defined media with different initial histidine, isoleucine, and glutamate concentrations. The results showed that f-EPS production and viable cell counts of Strep. thermophilus 937 increased 2-fold after the concentrations of His, Ile, and Glu were increased. Additionally, increasing the concentrations of His, Ile, and Glu upregulated transcription of EPS biosynthesis genes and increased the activity of key enzymes in sugar nucleotide synthesis. Moreover, the consumption of lactose increased and secretion of galactose decreased, indicating that increasing the concentration of His, Ile, and Glu could enhance f-EPS production by maintaining viable cell counts, promoting sugar nucleotide synthesis, and increasing the transcript levels of the eps gene cluster. Our results provide a better understanding of the effect of AA on EPS biosynthesis in Strep. thermophilus.
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Affiliation(s)
- Yunchao Wa
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Animal Science and Technology, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Chenchen Zhang
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Gulin Sun
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Hengxian Qu
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Dawei Chen
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Yujun Huang
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China
| | - Ruixia Gu
- Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou University, Yangzhou 225127, Jiangsu Province, China; College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu Province, China.
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4
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Rodionov DA, Rodionova IA, Rodionov VA, Arzamasov AA, Zhang K, Rubinstein GM, Tanwee TNN, Bing RG, Crosby JR, Nookaew I, Basen M, Brown SD, Wilson CM, Klingeman DM, Poole FL, Zhang Y, Kelly RM, Adams MWW. Transcriptional Regulation of Plant Biomass Degradation and Carbohydrate Utilization Genes in the Extreme Thermophile Caldicellulosiruptor bescii. mSystems 2021; 6:e0134520. [PMID: 34060910 PMCID: PMC8579813 DOI: 10.1128/msystems.01345-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/04/2021] [Indexed: 11/20/2022] Open
Abstract
Extremely thermophilic bacteria from the genus Caldicellulosiruptor can degrade polysaccharide components of plant cell walls and subsequently utilize the constituting mono- and oligosaccharides. Through metabolic engineering, ethanol and other industrially important end products can be produced. Previous experimental studies identified a variety of carbohydrate-active enzymes in model species Caldicellulosiruptor saccharolyticus and Caldicellulosiruptor bescii, while prior transcriptomic experiments identified their putative carbohydrate uptake transporters. We investigated the mechanisms of transcriptional regulation of carbohydrate utilization genes using a comparative genomics approach applied to 14 Caldicellulosiruptor species. The reconstruction of carbohydrate utilization regulatory network includes the predicted binding sites for 34 mostly local regulators and point to the regulatory mechanisms controlling expression of genes involved in degradation of plant biomass. The Rex and CggR regulons control the central glycolytic and primary redox reactions. The identified transcription factor binding sites and regulons were validated with transcriptomic and transcription start site experimental data for C. bescii grown on cellulose, cellobiose, glucose, xylan, and xylose. The XylR and XynR regulons control xylan-induced transcriptional response of genes involved in degradation of xylan and xylose utilization. The reconstructed regulons informed the carbohydrate utilization reconstruction analysis and improved functional annotations of 51 transporters and 11 catabolic enzymes. Using gene deletion, we confirmed that the shared ATPase component MsmK is essential for growth on oligo- and polysaccharides but not for the utilization of monosaccharides. By elucidating the carbohydrate utilization framework in C. bescii, strategies for metabolic engineering can be pursued to optimize yields of bio-based fuels and chemicals from lignocellulose. IMPORTANCE To develop functional metabolic engineering platforms for nonmodel microorganisms, a comprehensive understanding of the physiological and metabolic characteristics is critical. Caldicellulosiruptor bescii and other species in this genus have untapped potential for conversion of unpretreated plant biomass into industrial fuels and chemicals. The highly interactive and complex machinery used by C. bescii to acquire and process complex carbohydrates contained in lignocellulose was elucidated here to complement related efforts to develop a metabolic engineering platform with this bacterium. Guided by the findings here, a clearer picture of how C. bescii natively drives carbohydrate utilization is provided and strategies to engineer this bacterium for optimal conversion of lignocellulose to commercial products emerge.
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Affiliation(s)
- Dmitry A. Rodionov
- Sanford-Burnhams-Prebys Medical Discovery Institute, La Jolla, California, USA
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Irina A. Rodionova
- Department of Bioengineering, University of California—San Diego, La Jolla, California, USA
| | - Vladimir A. Rodionov
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Aleksandr A. Arzamasov
- Sanford-Burnhams-Prebys Medical Discovery Institute, La Jolla, California, USA
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Ke Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Gabriel M. Rubinstein
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Tania N. N. Tanwee
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Ryan G. Bing
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - James R. Crosby
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Intawat Nookaew
- Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Mirko Basen
- Mathematisch-Naturwissenschaftliche Fakultät, Institut für Biowissenschaften, Mikrobiologie, Universität Rostock, Rostock, Germany
| | - Steven D. Brown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Charlotte M. Wilson
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- University of Otago, Dunedin, New Zealand
| | - Dawn M. Klingeman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Farris L. Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Ying Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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5
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Genome-wide Identification of DNA-protein Interaction to Reconstruct Bacterial Transcription Regulatory Network. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-020-0030-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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6
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Prathiviraj R, Chellapandi P. Modeling a global regulatory network of Methanothermobacter thermautotrophicus strain ∆H. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s13721-020-0223-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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7
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RocA Has Serotype-Specific Gene Regulatory and Pathogenesis Activities in Serotype M28 Group A Streptococcus. Infect Immun 2018; 86:IAI.00467-18. [PMID: 30126898 DOI: 10.1128/iai.00467-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/13/2018] [Indexed: 12/21/2022] Open
Abstract
Serotype M28 group A streptococcus (GAS) is a common cause of infections such as pharyngitis ("strep throat") and necrotizing fasciitis ("flesh-eating" disease). Relatively little is known about the molecular mechanisms underpinning M28 GAS pathogenesis. Whole-genome sequencing studies of M28 GAS strains recovered from patients with invasive infections found an unexpectedly high number of missense (amino acid-changing) and nonsense (protein-truncating) polymorphisms in rocA (regulator of Cov), leading us to hypothesize that altered RocA activity contributes to M28 GAS molecular pathogenesis. To test this hypothesis, an isogenic rocA deletion mutant strain was created. Transcriptome sequencing (RNA-seq) analysis revealed that RocA inactivation significantly alters the level of transcripts for 427 and 323 genes at mid-exponential and early stationary growth phases, respectively, including genes for 41 transcription regulators and 21 virulence factors. In contrast, RocA transcriptomes from other GAS M protein serotypes are much smaller and include fewer transcription regulators. The rocA mutant strain had significantly increased secreted activity of multiple virulence factors and grew to significantly higher colony counts under acid stress in vitro RocA inactivation also significantly increased GAS virulence in a mouse model of necrotizing myositis. Our results demonstrate that RocA is an important regulator of transcription regulators and virulence factors in M28 GAS and raise the possibility that naturally occurring polymorphisms in rocA in some fashion contribute to human invasive infections caused by M28 GAS strains.
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Coda R, Xu Y, Moreno DS, Mojzita D, Nionelli L, Rizzello CG, Katina K. Performance of Leuconostoc citreum FDR241 during wheat flour sourdough type I propagation and transcriptional analysis of exopolysaccharides biosynthesis genes. Food Microbiol 2018; 76:164-172. [PMID: 30166137 DOI: 10.1016/j.fm.2018.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/28/2018] [Accepted: 05/12/2018] [Indexed: 12/23/2022]
Abstract
This study focused on the performance of the dextran producer Leuconostoc citreum as starter culture during 30 days of wheat flour type I sourdough propagation (back-slopping). As confirmed by RAPD-PCR analysis, the strain dominated throughout the propagation procedure, consisting of daily fermentations at 20 °C. The sourdoughs were characterized by consistent lactic acid bacteria cell density and acidification parameters, reaching pH values of 4.0 and mild titratable acidity. Carbohydrates consumption remained consistent during the propagation procedure, leading to formation of mannitol and almost equimolar amount of lactic and acetic acid. The addition of sucrose enabled the formation of dextran, inducing an increase in viscosity of the sourdough of 2-2.6 fold, as well as oligosaccharides. The transcriptional analysis based on glucosyltransferases genes (GH70) showed the existence in L. citreum FDR241 of at least five different dextransucrases. Among these, only one gene, previously identified as forming only α-(1-6) glycosidic bonds, was significantly upregulated in sourdough fermentation conditions, and the main responsible of dextran formation. A successful application of a starter culture during long sourdough back-slopping procedure will depend on the strain robustness and fermentation conditions. Transcriptional regulation of EPS-synthetizing genes might contribute to increase the efficiency of industrial processes.
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Affiliation(s)
- Rossana Coda
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland; Helsinki Institute of Sustainability Science, Finland.
| | - Yan Xu
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
| | - David Sàez Moreno
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
| | | | - Luana Nionelli
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
| | - Carlo G Rizzello
- Department of Soil, Plant and Food Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Kati Katina
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland
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Arzamasov AA, van Sinderen D, Rodionov DA. Comparative Genomics Reveals the Regulatory Complexity of Bifidobacterial Arabinose and Arabino-Oligosaccharide Utilization. Front Microbiol 2018; 9:776. [PMID: 29740413 PMCID: PMC5928203 DOI: 10.3389/fmicb.2018.00776] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/05/2018] [Indexed: 11/13/2022] Open
Abstract
Members of the genus Bifidobacterium are common inhabitants of the human gastrointestinal tract. Previously it was shown that arabino-oligosaccharides (AOS) might act as prebiotics and stimulate the bifidobacterial growth in the gut. However, despite the rapid accumulation of genomic data, the precise mechanisms by which these sugars are utilized and associated transcription control still remain unclear. In the current study, we used a comparative genomic approach to reconstruct arabinose and AOS utilization pathways in over 40 bacterial species belonging to the Bifidobacteriaceae family. The results indicate that the gene repertoire involved in the catabolism of these sugars is highly diverse, and even phylogenetically close species may differ in their utilization capabilities. Using bioinformatics analysis we identified potential DNA-binding motifs and reconstructed putative regulons for the arabinose and AOS utilization genes in the Bifidobacteriaceae genomes. Six LacI-family transcriptional factors (named AbfR, AauR, AauU1, AauU2, BauR1 and BauR2) and a TetR-family regulator (XsaR) presumably act as local repressors for AOS utilization genes encoding various α- or β-L-arabinofuranosidases and predicted AOS transporters. The ROK-family regulator AraU and the LacI-family regulator AraQ control adjacent operons encoding putative arabinose transporters and catabolic enzymes, respectively. However, the AraQ regulator is universally present in all Bifidobacterium species including those lacking the arabinose catabolic genes araBDA, suggesting its control of other genes. Comparative genomic analyses of prospective AraQ-binding sites allowed the reconstruction of AraQ regulons and a proposed binary repression/activation mechanism. The conserved core of reconstructed AraQ regulons in bifidobacteria includes araBDA, as well as genes from the central glycolytic and fermentation pathways (pyk, eno, gap, tkt, tal, galM, ldh). The current study expands the range of genes involved in bifidobacterial arabinose/AOS utilization and demonstrates considerable variations in associated metabolic pathways and regulons. Detailed comparative and phylogenetic analyses allowed us to hypothesize how the identified reconstructed regulons evolved in bifidobacteria. Our findings may help to improve carbohydrate catabolic phenotype prediction and metabolic modeling, while it may also facilitate rational development of novel prebiotics.
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Affiliation(s)
- Aleksandr A Arzamasov
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Douwe van Sinderen
- APC Microbiome Institute and School of Microbiology, University College Cork, Cork, Ireland
| | - Dmitry A Rodionov
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia.,Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
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Fu C, Deng S, Jin G, Wang X, Yu ZG. Bayesian network model for identification of pathways by integrating protein interaction with genetic interaction data. BMC SYSTEMS BIOLOGY 2017; 11:81. [PMID: 28950903 PMCID: PMC5615243 DOI: 10.1186/s12918-017-0454-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Molecular interaction data at proteomic and genetic levels provide physical and functional insights into a molecular biosystem and are helpful for the construction of pathway structures complementarily. Despite advances in inferring biological pathways using genetic interaction data, there still exists weakness in developed models, such as, activity pathway networks (APN), when integrating the data from proteomic and genetic levels. It is necessary to develop new methods to infer pathway structure by both of interaction data. Results We utilized probabilistic graphical model to develop a new method that integrates genetic interaction and protein interaction data and infers exquisitely detailed pathway structure. We modeled the pathway network as Bayesian network and applied this model to infer pathways for the coherent subsets of the global genetic interaction profiles, and the available data set of endoplasmic reticulum genes. The protein interaction data were derived from the BioGRID database. Our method can accurately reconstruct known cellular pathway structures, including SWR complex, ER-Associated Degradation (ERAD) pathway, N-Glycan biosynthesis pathway, Elongator complex, Retromer complex, and Urmylation pathway. By comparing N-Glycan biosynthesis pathway and Urmylation pathway identified from our approach with that from APN, we found that our method is able to overcome its weakness (certain edges are inexplicable). According to underlying protein interaction network, we defined a simple scoring function that only adopts genetic interaction information to avoid the balance difficulty in the APN. Using the effective stochastic simulation algorithm, the performance of our proposed method is significantly high. Conclusion We developed a new method based on Bayesian network to infer detailed pathway structures from interaction data at proteomic and genetic levels. The results indicate that the developed method performs better in predicting signaling pathways than previously described models.
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Affiliation(s)
- Changhe Fu
- School of Mathematics and Computational Science, Xiangtan University, Xiangtan, 411105, China. .,School of Mathematics and System Science, Shenyang Normal University, Shenyang, 110034, China.
| | - Su Deng
- School of Mathematics and System Science, Shenyang Normal University, Shenyang, 110034, China
| | - Guangxu Jin
- Center of Systems Biology and Bioinformatics, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Xinxin Wang
- School of Mathematics and System Science, Shenyang Normal University, Shenyang, 110034, China
| | - Zu-Guo Yu
- School of Mathematics and Computational Science, Xiangtan University, Xiangtan, 411105, China.
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11
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Zeidan AA, Poulsen VK, Janzen T, Buldo P, Derkx PMF, Øregaard G, Neves AR. Polysaccharide production by lactic acid bacteria: from genes to industrial applications. FEMS Microbiol Rev 2017; 41:S168-S200. [DOI: 10.1093/femsre/fux017] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/29/2017] [Indexed: 01/14/2023] Open
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12
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Kaur M, Jayaraman G. Hyaluronan production and molecular weight is enhanced in pathway-engineered strains of lactate dehydrogenase-deficient Lactococcus lactis. Metab Eng Commun 2016; 3:15-23. [PMID: 29468110 PMCID: PMC5779726 DOI: 10.1016/j.meteno.2016.01.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 11/08/2015] [Accepted: 01/19/2016] [Indexed: 12/31/2022] Open
Abstract
The potential advantages of hyaluronic acid (HA) production by metabolically-engineered Lactococcus lactis is constrained by the lower molecular weight and yield of HA obtained in these strains, compared to natural producers. Earlier studies have correlated lower HA yield with excessive lactate production in L. lactis cultures (Chauhan et al., 2014). In the present study, a three-fold increase was observed in the amount as well as molecular weight of HA produced by recombinant ldh-mutant L. lactis strains. The diversion from lactate production in the ldh-mutant strains resulted in excess ethanol and acetoin production and higher NAD+/NADH ratio in these cultures. The initial NAD+/NADH ratio showed a positive correlation with HA molecular weight as well as with the HA-precursor ratio (UDP-GlcUA/UDP-GlcNAc). The influence of NAD+/NADH ratio on regulation of the concerned metabolic pathways was assessed by transcriptional analysis of key genes having putative binding sites of the NADH-binding transcriptional factor, Rex.
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Affiliation(s)
| | - Guhan Jayaraman
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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13
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Leyn SA, Suvorova IA, Kazakov AE, Ravcheev DA, Stepanova VV, Novichkov PS, Rodionov DA. Comparative genomics and evolution of transcriptional regulons in Proteobacteria. Microb Genom 2016; 2:e000061. [PMID: 28348857 PMCID: PMC5343134 DOI: 10.1099/mgen.0.000061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 04/14/2016] [Indexed: 12/16/2022] Open
Abstract
Comparative genomics approaches are broadly used for analysis of transcriptional regulation in bacterial genomes. In this work, we identified binding sites and reconstructed regulons for 33 orthologous groups of transcription factors (TFs) in 196 reference genomes from 21 taxonomic groups of Proteobacteria. Overall, we predict over 10 600 TF binding sites and identified more than 15 600 target genes for 1896 TFs constituting the studied orthologous groups of regulators. These include a set of orthologues for 21 metabolism-associated TFs from Escherichia coli and/or Shewanella that are conserved in five or more taxonomic groups and several additional TFs that represent non-orthologous substitutions of the metabolic regulators in some lineages of Proteobacteria. By comparing gene contents of the reconstructed regulons, we identified the core, taxonomy-specific and genome-specific TF regulon members and classified them by their metabolic functions. Detailed analysis of ArgR, TyrR, TrpR, HutC, HypR and other amino-acid-specific regulons demonstrated remarkable differences in regulatory strategies used by various lineages of Proteobacteria. The obtained genomic collection of in silico reconstructed TF regulons contains a large number of new regulatory interactions that await future experimental validation. The collection provides a framework for future evolutionary studies of transcriptional regulatory networks in Bacteria. It can be also used for functional annotation of putative metabolic transporters and enzymes that are abundant in the reconstructed regulons.
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Affiliation(s)
- Semen A Leyn
- 1A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Inna A Suvorova
- 1A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Alexey E Kazakov
- 2Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Vita V Stepanova
- 1A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Dmitry A Rodionov
- 4Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.,1A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
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14
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Khoroshkin MS, Leyn SA, Van Sinderen D, Rodionov DA. Transcriptional Regulation of Carbohydrate Utilization Pathways in the Bifidobacterium Genus. Front Microbiol 2016; 7:120. [PMID: 26903998 PMCID: PMC4746261 DOI: 10.3389/fmicb.2016.00120] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/22/2016] [Indexed: 12/21/2022] Open
Abstract
Bifidobacteria, which represent common commensals of mammalian gut, are believed to have positive effects on human health. The influence of certain non-digestible carbohydrates (and their use as so-called prebiotics) on growth and metabolic activity of bifidobacteria is of increasing interest; however, mechanisms of transcriptional control of carbohydrate metabolism are poorly understood in these species. We used a comparative genomics approach to reconstruct carbohydrate utilization pathways and transcriptional regulons in 10 Bifidobacterium genomes. Analysis of regulatory gene regions revealed candidate DNA motifs and reconstructed regulons for 268 transcription factors from the LacI, ROK, DeoR, AraC, GntR, and TetR families that form 64 orthologous groups of regulators. Most of the reconstructed regulons are local and control specific catabolic pathways for host- and diet-derived glycans and monosaccharides. Mosaic distributions of many of these local regulators across Bifidobacterium species correlate with distribution of corresponding catabolic pathways. In contrast, the maltose, galactose, sucrose, and fructose regulons, as well as a novel global LacI-family regulator that is predicted to control the central carbohydrate metabolism and arabinose catabolism genes, are universally present in all 10 studied bifidobacteria. A novel group of TetR-family regulators presumably controls the glucoside and galactoside utilization pathways. Paralogs of the ribose repressor RbsR control the pyrimidine nucleoside utilization genes. Multiple paralogs of the maltose regulator MalR co-regulate large sets of genes involved in maltodextrin utilization. The inferred metabolic regulons provide new insights on diverse carbohydrate utilization networks in bifidobacteria that can be employed in metabolic modeling, phenotype prediction and the rational development of novel prebiotics.
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Affiliation(s)
- Matvei S Khoroshkin
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Semen A Leyn
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Douwe Van Sinderen
- School of Microbiology and Alimentary Pharmabiotic Centre Microbiome Institute, University College Cork Cork, Ireland
| | - Dmitry A Rodionov
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia; Sanford Burnham Prebys Medical Discovery InstituteLa Jolla, CA, USA
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Suvorova IA, Rodionov DA. Comparative genomics of pyridoxal 5'-phosphate-dependent transcription factor regulons in Bacteria. Microb Genom 2016; 2:e000047. [PMID: 28348826 PMCID: PMC5320631 DOI: 10.1099/mgen.0.000047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022] Open
Abstract
The MocR-subfamily transcription factors (MocR-TFs) characterized by the GntR-family DNA-binding domain and aminotransferase-like sensory domain are broadly distributed among certain lineages of Bacteria. Characterized MocR-TFs bind pyridoxal 5'-phosphate (PLP) and control transcription of genes involved in PLP, gamma aminobutyric acid (GABA) and taurine metabolism via binding specific DNA operator sites. To identify putative target genes and DNA binding motifs of MocR-TFs, we performed comparative genomics analysis of over 250 bacterial genomes. The reconstructed regulons for 825 MocR-TFs comprise structural genes from over 200 protein families involved in diverse biological processes. Using the genome context and metabolic subsystem analysis we tentatively assigned functional roles for 38 out of 86 orthologous groups of studied regulators. Most of these MocR-TF regulons are involved in PLP metabolism, as well as utilization of GABA, taurine and ectoine. The remaining studied MocR-TF regulators presumably control genes encoding enzymes involved in reduction/oxidation processes, various transporters and PLP-dependent enzymes, for example aminotransferases. Predicted DNA binding motifs of MocR-TFs are generally similar in each orthologous group and are characterized by two to four repeated sequences. Identified motifs were classified according to their structures. Motifs with direct and/or inverted repeat symmetry constitute the majority of inferred DNA motifs, suggesting preferable TF dimerization in head-to-tail or head-to-head configuration. The obtained genomic collection of in silico reconstructed MocR-TF motifs and regulons in Bacteria provides a basis for future experimental characterization of molecular mechanisms for various regulators in this family.
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Affiliation(s)
- Inna A. Suvorova
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Science, Moscow, Russia
| | - Dmitry A. Rodionov
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Science, Moscow, Russia
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
- Correspondence D. A. Rodionov ()
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16
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Zhang H, Ravcheev DA, Hu D, Zhang F, Gong X, Hao L, Cao M, Rodionov DA, Wang C, Feng Y. Two novel regulators of N-acetyl-galactosamine utilization pathway and distinct roles in bacterial infections. Microbiologyopen 2015; 4:983-1000. [PMID: 26540018 PMCID: PMC4694137 DOI: 10.1002/mbo3.307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/21/2015] [Accepted: 09/28/2015] [Indexed: 12/19/2022] Open
Abstract
Bacterial pathogens can exploit metabolic pathways to facilitate their successful infection cycles, but little is known about roles of d‐galactosamine (GalN)/N‐acetyl‐d‐galactosamine (GalNAc) catabolism pathway in bacterial pathogenesis. Here, we report the genomic reconstruction of GalN/GalNAc utilization pathway in Streptococci and the diversified aga regulons. We delineated two new paralogous AgaR regulators for the GalN/GalNAc catabolism pathway. The electrophoretic mobility shift assays experiment demonstrated that AgaR2 (AgaR1) binds the predicted palindromes, and the combined in vivo data from reverse transcription quantitative polymerase chain reaction and RNA‐seq suggested that AgaR2 (not AgaR1) can effectively repress the transcription of the target genes. Removal of agaR2 (not agaR1) from Streptococcus suis 05ZYH33 augments significantly the abilities of both adherence to Hep‐2 cells and anti‐phagocytosis against RAW264.7 macrophage. As anticipated, the dysfunction in AgaR2‐mediated regulation of S. suis impairs its pathogenicity in experimental models of both mice and piglets. Our finding discovered two novel regulators specific for GalN/GalNAc catabolism and assigned them distinct roles into bacterial infections. To the best of our knowledge, it might represent a first paradigm that links the GalN/GalNAc catabolism pathway to bacterial pathogenesis.
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Affiliation(s)
- Huimin Zhang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Dmitry A Ravcheev
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, L-4360, Luxembourg
| | - Dan Hu
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Fengyu Zhang
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Xiufang Gong
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Lina Hao
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Min Cao
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Dmitry A Rodionov
- A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia
| | - Changjun Wang
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, 210002, China
| | - Youjun Feng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
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17
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Bitoun JP, Wen ZT. Transcription factor Rex in regulation of pathophysiology in oral pathogens. Mol Oral Microbiol 2015; 31:115-24. [PMID: 26172563 DOI: 10.1111/omi.12114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2015] [Indexed: 11/29/2022]
Abstract
The NAD(+) and NADH-sensing transcriptional regulator Rex is widely conserved across gram-positive bacteria. Rex monitors cellular redox poise and controls the expression of genes/operons involved in diverse pathways including alternative fermentation, oxidative stress responses, and biofilm formation. The oral cavity undergoes frequent and drastic fluctuations in nutrient availability, pH, temperature, oxygen tension, saliva, and shear forces. The oral streptococci are major colonizers of oral mucosa and tooth surfaces and include commensals as well as opportunistic pathogens, including the primary etiological agent of dental caries, Streptococcus mutans. Current understanding of the Rex regulon in oral bacteria is mostly based on studies in S. mutans and endodontic pathogen Enterococcus faecalis. Indeed, other oral bacteria encode homologs of the Rex protein and much is to be gleaned from more in-depth studies. Our current understanding has Rex positioned at the interface of oxygen and energy metabolism. In biofilms, heterogeneous oxygen tension influences the ratio of intracellular NADH and NAD(+) , which is finely tuned through glycolysis and fermentation. In S. mutans, Rex regulates the expression of glycolytic enzyme NAD(+) -dependent glyceraldehyde 3-phosphate dehydrogenase, and NADH-dependent fermentation enzymes/complexes lactate dehydrogenase, pyruvate dehydrogenase, alcohol-acetaldehyde dehydrogenase, and fumarate reductase. In addition, Rex controls the expression of NADH oxidase, a major enzyme used to eliminate oxidative stress and regenerate NAD(+) . Here, we summarize recent studies carried out on the Rex regulators in S. mutans and E. faecalis. This research has important implications for understanding how Rex monitors redox balance and optimizes fermentation pathways for survival and subsequent pathogenicity.
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Affiliation(s)
- J P Bitoun
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Z T Wen
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Center of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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18
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Nguyen HA, Vu CL, Tu MP, Bui TL. Discovery of pathways in protein–protein interaction networks using a genetic algorithm. DATA KNOWL ENG 2015. [DOI: 10.1016/j.datak.2015.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chan SHJ, Solem C, Jensen PR, Ji P. Estimating biological elementary flux modes that decompose a flux distribution by the minimal branching property. ACTA ACUST UNITED AC 2014; 30:3232-9. [PMID: 25100687 DOI: 10.1093/bioinformatics/btu529] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
MOTIVATION Elementary flux mode (EFM) is a useful tool in constraint-based modeling of metabolic networks. The property that every flux distribution can be decomposed as a weighted sum of EFMs allows certain applications of EFMs to studying flux distributions. The existence of biologically infeasible EFMs and the non-uniqueness of the decomposition, however, undermine the applicability of such methods. Efforts have been made to find biologically feasible EFMs by incorporating information from transcriptional regulation and thermodynamics. Yet, no attempt has been made to distinguish biologically feasible EFMs by considering their graphical properties. A previous study on the transcriptional regulation of metabolic genes found that distinct branches at a branch point metabolite usually belong to distinct metabolic pathways. This suggests an intuitive property of biologically feasible EFMs, i.e. minimal branching. RESULTS We developed the concept of minimal branching EFM and derived the minimal branching decomposition (MBD) to decompose flux distributions. Testing in the core Escherichia coli metabolic network indicated that MBD can distinguish branches at branch points and greatly reduced the solution space in which the decomposition is often unique. An experimental flux distribution from a previous study on mouse cardiomyocyte was decomposed using MBD. Comparison with decomposition by a minimum number of EFMs showed that MBD found EFMs more consistent with established biological knowledge, which facilitates interpretation. Comparison of the methods applied to a complex flux distribution in Lactococcus lactis similarly showed the advantages of MBD. The minimal branching EFM concept underlying MBD should be useful in other applications. CONTACT sinhu@bio.dtu.dk or p.ji@polyu.edu.hk SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Siu Hung Joshua Chan
- Systems Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark and Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Christian Solem
- Systems Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark and Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Peter Ruhdal Jensen
- Systems Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark and Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Ping Ji
- Systems Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark and Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
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20
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Ravcheev DA, Khoroshkin MS, Laikova ON, Tsoy OV, Sernova NV, Petrova SA, Rakhmaninova AB, Novichkov PS, Gelfand MS, Rodionov DA. Comparative genomics and evolution of regulons of the LacI-family transcription factors. Front Microbiol 2014; 5:294. [PMID: 24966856 PMCID: PMC4052901 DOI: 10.3389/fmicb.2014.00294] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 05/28/2014] [Indexed: 12/31/2022] Open
Abstract
DNA-binding transcription factors (TFs) are essential components of transcriptional regulatory networks in bacteria. LacI-family TFs (LacI-TFs) are broadly distributed among certain lineages of bacteria. The majority of characterized LacI-TFs sense sugar effectors and regulate carbohydrate utilization genes. The comparative genomics approaches enable in silico identification of TF-binding sites and regulon reconstruction. To study the function and evolution of LacI-TFs, we performed genomics-based reconstruction and comparative analysis of their regulons. For over 1300 LacI-TFs from over 270 bacterial genomes, we predicted their cognate DNA-binding motifs and identified target genes. Using the genome context and metabolic subsystem analyses of reconstructed regulons, we tentatively assigned functional roles and predicted candidate effectors for 78 and 67% of the analyzed LacI-TFs, respectively. Nearly 90% of the studied LacI-TFs are local regulators of sugar utilization pathways, whereas the remaining 125 global regulators control large and diverse sets of metabolic genes. The global LacI-TFs include the previously known regulators CcpA in Firmicutes, FruR in Enterobacteria, and PurR in Gammaproteobacteria, as well as the three novel regulators—GluR, GapR, and PckR—that are predicted to control the central carbohydrate metabolism in three lineages of Alphaproteobacteria. Phylogenetic analysis of regulators combined with the reconstructed regulons provides a model of evolutionary diversification of the LacI protein family. The obtained genomic collection of in silico reconstructed LacI-TF regulons in bacteria is available in the RegPrecise database (http://regprecise.lbl.gov). It provides a framework for future structural and functional classification of the LacI protein family and identification of molecular determinants of the DNA and ligand specificity. The inferred regulons can be also used for functional gene annotation and reconstruction of sugar catabolic networks in diverse bacterial lineages.
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Affiliation(s)
- Dmitry A Ravcheev
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Matvei S Khoroshkin
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Olga N Laikova
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Olga V Tsoy
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia ; Faculty of Bioengineering and Bioinformatics, Moscow State University Moscow, Russia
| | - Natalia V Sernova
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Svetlana A Petrova
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia ; Faculty of Bioengineering and Bioinformatics, Moscow State University Moscow, Russia
| | | | - Pavel S Novichkov
- Lawrence Berkeley National Laboratory, Genomics Division Berkeley, CA, USA
| | - Mikhail S Gelfand
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Dmitry A Rodionov
- Research Scientific Center for Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia ; Department of Bioinformatics, Sanford-Burnham Medical Research Institute La Jolla, CA, USA
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Rodionova IA, Li X, Thiel V, Stolyar S, Stanton K, Fredrickson JK, Bryant DA, Osterman AL, Best AA, Rodionov DA. Comparative genomics and functional analysis of rhamnose catabolic pathways and regulons in bacteria. Front Microbiol 2013; 4:407. [PMID: 24391637 PMCID: PMC3870299 DOI: 10.3389/fmicb.2013.00407] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/09/2013] [Indexed: 12/29/2022] Open
Abstract
L-rhamnose (L-Rha) is a deoxy-hexose sugar commonly found in nature. L-Rha catabolic pathways were previously characterized in various bacteria including Escherichia coli. Nevertheless, homology searches failed to recognize all the genes for the complete L-Rha utilization pathways in diverse microbial species involved in biomass decomposition. Moreover, the regulatory mechanisms of L-Rha catabolism have remained unclear in most species. A comparative genomics approach was used to reconstruct the L-Rha catabolic pathways and transcriptional regulons in the phyla Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, and Thermotogae. The reconstructed pathways include multiple novel enzymes and transporters involved in the utilization of L-Rha and L-Rha-containing polymers. Large-scale regulon inference using bioinformatics revealed remarkable variations in transcriptional regulators for L-Rha utilization genes among bacteria. A novel bifunctional enzyme, L-rhamnulose-phosphate aldolase (RhaE) fused to L-lactaldehyde dehydrogenase (RhaW), which is not homologous to previously characterized L-Rha catabolic enzymes, was identified in diverse bacteria including Chloroflexi, Bacilli, and Alphaproteobacteria. By using in vitro biochemical assays we validated both enzymatic activities of the purified recombinant RhaEW proteins from Chloroflexus aurantiacus and Bacillus subtilis. Another novel enzyme of the L-Rha catabolism, L-lactaldehyde reductase (RhaZ), was identified in Gammaproteobacteria and experimentally validated by in vitro enzymatic assays using the recombinant protein from Salmonella typhimurium. C. aurantiacus induced transcription of the predicted L-Rha utilization genes when L-Rha was present in the growth medium and consumed L-Rha from the medium. This study provided comprehensive insights to L-Rha catabolism and its regulation in diverse Bacteria.
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Affiliation(s)
| | - Xiaoqing Li
- Sanford-Burnham Medical Research Institute La Jolla, CA, USA
| | - Vera Thiel
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park PA, USA
| | - Sergey Stolyar
- Pacific Northwest National Laboratory, Biological Sciences Division Richland, WA, USA
| | | | - James K Fredrickson
- Pacific Northwest National Laboratory, Biological Sciences Division Richland, WA, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park PA, USA ; Department of Chemistry and Biochemistry, Montana State University Bozeman, MT, USA
| | | | - Aaron A Best
- Department of Biology, Hope College Holland, MI, USA
| | - Dmitry A Rodionov
- Sanford-Burnham Medical Research Institute La Jolla, CA, USA ; A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
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22
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Ravcheev DA, Godzik A, Osterman AL, Rodionov DA. Polysaccharides utilization in human gut bacterium Bacteroides thetaiotaomicron: comparative genomics reconstruction of metabolic and regulatory networks. BMC Genomics 2013; 14:873. [PMID: 24330590 PMCID: PMC3878776 DOI: 10.1186/1471-2164-14-873] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 12/06/2013] [Indexed: 01/14/2023] Open
Abstract
Background Bacteroides thetaiotaomicron, a predominant member of the human gut microbiota, is characterized by its ability to utilize a wide variety of polysaccharides using the extensive saccharolytic machinery that is controlled by an expanded repertoire of transcription factors (TFs). The availability of genomic sequences for multiple Bacteroides species opens an opportunity for their comparative analysis to enable characterization of their metabolic and regulatory networks. Results A comparative genomics approach was applied for the reconstruction and functional annotation of the carbohydrate utilization regulatory networks in 11 Bacteroides genomes. Bioinformatics analysis of promoter regions revealed putative DNA-binding motifs and regulons for 31 orthologous TFs in the Bacteroides. Among the analyzed TFs there are 4 SusR-like regulators, 16 AraC-like hybrid two-component systems (HTCSs), and 11 regulators from other families. Novel DNA motifs of HTCSs and SusR-like regulators in the Bacteroides have the common structure of direct repeats with a long spacer between two conserved sites. Conclusions The inferred regulatory network in B. thetaiotaomicron contains 308 genes encoding polysaccharide and sugar catabolic enzymes, carbohydrate-binding and transport systems, and TFs. The analyzed TFs control pathways for utilization of host and dietary glycans to monosaccharides and their further interconversions to intermediates of the central metabolism. The reconstructed regulatory network allowed us to suggest and refine specific functional assignments for sugar catabolic enzymes and transporters, providing a substantial improvement to the existing metabolic models for B. thetaiotaomicron. The obtained collection of reconstructed TF regulons is available in the RegPrecise database (http://regprecise.lbl.gov).
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Affiliation(s)
| | | | | | - Dmitry A Rodionov
- Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
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Hagi T, Kobayashi M, Nomura M. Aerobic condition increases carotenoid production associated with oxidative stress tolerance in Enterococcus gilvus. FEMS Microbiol Lett 2013; 350:223-30. [PMID: 24325446 DOI: 10.1111/1574-6968.12341] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/11/2013] [Accepted: 11/14/2013] [Indexed: 01/10/2023] Open
Abstract
Although it is known that a part of lactic acid bacteria can produce carotenoid, little is known about the regulation of carotenoid production. The objective of this study was to determine whether aerobic growth condition influences carotenoid production in carotenoid-producing Enterococcus gilvus. Enterococcus gilvus was grown under aerobic and anaerobic conditions. Its growth was slower under aerobic than under anaerobic conditions. The decrease in pH levels and production of lactic acid were also lower under aerobic than under anaerobic conditions. In contrast, the amount of carotenoid pigments produced by E. gilvus was significantly higher under aerobic than under anaerobic conditions. Further, real-time quantitative reverse transcription PCR revealed that the expression level of carotenoid biosynthesis genes crtN and crtM when E. gilvus was grown under aerobic conditions was 2.55-5.86-fold higher than when it was grown under anaerobic conditions. Moreover, after exposure to 16- and 32-mM H2O2, the survival rate of E. gilvus grown under aerobic conditions was 61.5- and 72.5-fold higher, respectively, than when it was grown under anaerobic conditions. Aerobic growth conditions significantly induced carotenoid production and the expression of carotenoid biosynthesis genes in E. gilvus, resulting in increased oxidative stress tolerance.
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Affiliation(s)
- Tatsuro Hagi
- Animal Products Research Division, NARO Institute of Livestock and Grassland Science, Ibaraki, Japan
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24
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Novichkov PS, Kazakov AE, Ravcheev DA, Leyn SA, Kovaleva GY, Sutormin RA, Kazanov MD, Riehl W, Arkin AP, Dubchak I, Rodionov DA. RegPrecise 3.0--a resource for genome-scale exploration of transcriptional regulation in bacteria. BMC Genomics 2013; 14:745. [PMID: 24175918 PMCID: PMC3840689 DOI: 10.1186/1471-2164-14-745] [Citation(s) in RCA: 274] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 10/28/2013] [Indexed: 11/27/2022] Open
Abstract
Background Genome-scale prediction of gene regulation and reconstruction of transcriptional regulatory networks in prokaryotes is one of the critical tasks of modern genomics. Bacteria from different taxonomic groups, whose lifestyles and natural environments are substantially different, possess highly diverged transcriptional regulatory networks. The comparative genomics approaches are useful for in silico reconstruction of bacterial regulons and networks operated by both transcription factors (TFs) and RNA regulatory elements (riboswitches). Description RegPrecise (http://regprecise.lbl.gov) is a web resource for collection, visualization and analysis of transcriptional regulons reconstructed by comparative genomics. We significantly expanded a reference collection of manually curated regulons we introduced earlier. RegPrecise 3.0 provides access to inferred regulatory interactions organized by phylogenetic, structural and functional properties. Taxonomy-specific collections include 781 TF regulogs inferred in more than 160 genomes representing 14 taxonomic groups of Bacteria. TF-specific collections include regulogs for a selected subset of 40 TFs reconstructed across more than 30 taxonomic lineages. Novel collections of regulons operated by RNA regulatory elements (riboswitches) include near 400 regulogs inferred in 24 bacterial lineages. RegPrecise 3.0 provides four classifications of the reference regulons implemented as controlled vocabularies: 55 TF protein families; 43 RNA motif families; ~150 biological processes or metabolic pathways; and ~200 effectors or environmental signals. Genome-wide visualization of regulatory networks and metabolic pathways covered by the reference regulons are available for all studied genomes. A separate section of RegPrecise 3.0 contains draft regulatory networks in 640 genomes obtained by an conservative propagation of the reference regulons to closely related genomes. Conclusions RegPrecise 3.0 gives access to the transcriptional regulons reconstructed in bacterial genomes. Analytical capabilities include exploration of: regulon content, structure and function; TF binding site motifs; conservation and variations in genome-wide regulatory networks across all taxonomic groups of Bacteria. RegPrecise 3.0 was selected as a core resource on transcriptional regulation of the Department of Energy Systems Biology Knowledgebase, an emerging software and data environment designed to enable researchers to collaboratively generate, test and share new hypotheses about gene and protein functions, perform large-scale analyses, and model interactions in microbes, plants, and their communities.
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Novichkov PS, Li X, Kuehl JV, Deutschbauer AM, Arkin AP, Price MN, Rodionov DA. Control of methionine metabolism by the SahR transcriptional regulator in Proteobacteria. Environ Microbiol 2013; 16:1-8. [PMID: 24118949 DOI: 10.1111/1462-2920.12273] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Sulphur is an essential element in the metabolism. The sulphur-containing amino acid methionine is a metabolic precursor for S-adenosylmethionine (SAM), which serves as a coenzyme for ubiquitous methyltrtansferases. Recycling of organic sulphur compounds, e.g. via the SAM cycle, is an important metabolic process that needs to be tightly regulated. Knowledge about transcriptional regulation of these processes is still limited for many free-living bacteria. We identified a novel transcription factor SahR from the ArsR family that controls the SAM cycle genes in diverse microorganisms from soil and aquatic ecosystems. By using comparative genomics, we predicted SahR-binding DNA motifs and reconstructed SahR regulons in the genomes of 62 Proteobacteria. The conserved core of SahR regulons includes all enzymes required for the SAM cycle: the SAH hydrolase AhcY, the methionine biosynthesis enzymes MetE/MetH and MetF, and the SAM synthetase MetK. By using a combination of experimental techniques, we validated the SahR regulon in the sulphate-reducing Deltaproteobacterium Desulfovibrio alaskensis. SahR functions as a negative regulator that responds to the S-adenosylhomocysteine (SAH). The elevated SAH level in the cell dissociates SahR from its DNA operators and induces the expression of SAM cycle genes. The effector-sensing domain in SahR is related to SAM-dependent methylases that are able to tightly bind SAH. SahR represents a novel type of transcriptional regulators for the control of sulphur amino acid metabolism.
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Affiliation(s)
- Pavel S Novichkov
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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Rodionov DA, Rodionova IA, Li X, Ravcheev DA, Tarasova Y, Portnoy VA, Zengler K, Osterman AL. Transcriptional regulation of the carbohydrate utilization network in Thermotoga maritima. Front Microbiol 2013; 4:244. [PMID: 23986752 PMCID: PMC3750489 DOI: 10.3389/fmicb.2013.00244] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/31/2013] [Indexed: 01/01/2023] Open
Abstract
Hyperthermophilic bacteria from the Thermotogales lineage can produce hydrogen by fermenting a wide range of carbohydrates. Previous experimental studies identified a large fraction of genes committed to carbohydrate degradation and utilization in the model bacterium Thermotoga maritima. Knowledge of these genes enabled comprehensive reconstruction of biochemical pathways comprising the carbohydrate utilization network. However, transcriptional factors (TFs) and regulatory mechanisms driving this network remained largely unknown. Here, we used an integrated approach based on comparative analysis of genomic and transcriptomic data for the reconstruction of the carbohydrate utilization regulatory networks in 11 Thermotogales genomes. We identified DNA-binding motifs and regulons for 19 orthologous TFs in the Thermotogales. The inferred regulatory network in T. maritima contains 181 genes encoding TFs, sugar catabolic enzymes and ABC-family transporters. In contrast to many previously described bacteria, a transcriptional regulation strategy of Thermotoga does not employ global regulatory factors. The reconstructed regulatory network in T. maritima was validated by gene expression profiling on a panel of mono- and disaccharides and by in vitro DNA-binding assays. The observed upregulation of genes involved in catabolism of pectin, trehalose, cellobiose, arabinose, rhamnose, xylose, glucose, galactose, and ribose showed a strong correlation with the UxaR, TreR, BglR, CelR, AraR, RhaR, XylR, GluR, GalR, and RbsR regulons. Ultimately, this study elucidated the transcriptional regulatory network and mechanisms controlling expression of carbohydrate utilization genes in T. maritima. In addition to improving the functional annotations of associated transporters and catabolic enzymes, this research provides novel insights into the evolution of regulatory networks in Thermotogales.
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Affiliation(s)
- Dmitry A Rodionov
- Sanford-Burnham Medical Research Institute La Jolla, CA, USA ; A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
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Leyn SA, Kazanov MD, Sernova NV, Ermakova EO, Novichkov PS, Rodionov DA. Genomic reconstruction of the transcriptional regulatory network in Bacillus subtilis. J Bacteriol 2013; 195:2463-73. [PMID: 23504016 PMCID: PMC3676070 DOI: 10.1128/jb.00140-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/11/2013] [Indexed: 12/26/2022] Open
Abstract
The adaptation of microorganisms to their environment is controlled by complex transcriptional regulatory networks (TRNs), which are still only partially understood even for model species. Genome scale annotation of regulatory features of genes and TRN reconstruction are challenging tasks of microbial genomics. We used the knowledge-driven comparative-genomics approach implemented in the RegPredict Web server to infer TRN in the model Gram-positive bacterium Bacillus subtilis and 10 related Bacillales species. For transcription factor (TF) regulons, we combined the available information from the DBTBS database and the literature with bioinformatics tools, allowing inference of TF binding sites (TFBSs), comparative analysis of the genomic context of predicted TFBSs, functional assignment of target genes, and effector prediction. For RNA regulons, we used known RNA regulatory motifs collected in the Rfam database to scan genomes and analyze the genomic context of new RNA sites. The inferred TRN in B. subtilis comprises regulons for 129 TFs and 24 regulatory RNA families. First, we analyzed 66 TF regulons with previously known TFBSs in B. subtilis and projected them to other Bacillales genomes, resulting in refinement of TFBS motifs and identification of novel regulon members. Second, we inferred motifs and described regulons for 28 experimentally studied TFs with previously unknown TFBSs. Third, we discovered novel motifs and reconstructed regulons for 36 previously uncharacterized TFs. The inferred collection of regulons is available in the RegPrecise database (http://regprecise.lbl.gov/) and can be used in genetic experiments, metabolic modeling, and evolutionary analysis.
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Affiliation(s)
- Semen A. Leyn
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Marat D. Kazanov
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Natalia V. Sernova
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina O. Ermakova
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Dmitry A. Rodionov
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
- A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
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