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Hogan AM, Cardona ST. Gradients in gene essentiality reshape antibacterial research. FEMS Microbiol Rev 2022; 46:fuac005. [PMID: 35104846 PMCID: PMC9075587 DOI: 10.1093/femsre/fuac005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/03/2023] Open
Abstract
Essential genes encode the processes that are necessary for life. Until recently, commonly applied binary classifications left no space between essential and non-essential genes. In this review, we frame bacterial gene essentiality in the context of genetic networks. We explore how the quantitative properties of gene essentiality are influenced by the nature of the encoded process, environmental conditions and genetic background, including a strain's distinct evolutionary history. The covered topics have important consequences for antibacterials, which inhibit essential processes. We argue that the quantitative properties of essentiality can thus be used to prioritize antibacterial cellular targets and desired spectrum of activity in specific infection settings. We summarize our points with a case study on the core essential genome of the cystic fibrosis pathobiome and highlight avenues for targeted antibacterial development.
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Affiliation(s)
- Andrew M Hogan
- Department of Microbiology, University of Manitoba, 45 Chancellor's Circle, Winnipeg, Manitoba R3T 2N2, Canada
| | - Silvia T Cardona
- Department of Microbiology, University of Manitoba, 45 Chancellor's Circle, Winnipeg, Manitoba R3T 2N2, Canada
- Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Room 543 - 745 Bannatyne Avenue, Winnipeg, Manitoba, R3E 0J9, Canada
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Dilucca M, Cimini G, Giansanti A. Bacterial Protein Interaction Networks: Connectivity is Ruled by Gene Conservation, Essentiality and Function. Curr Genomics 2021; 22:111-121. [PMID: 34220298 PMCID: PMC8188579 DOI: 10.2174/1389202922666210219110831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/13/2020] [Accepted: 08/27/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Protein-protein interaction (PPI) networks are the backbone of all processes in living cells. In this work, we relate conservation, essentiality and functional repertoire of a gene to the connectivity k (i.e. the number of interactions, links) of the corresponding protein in the PPI network. METHODS On a set of 42 bacterial genomes of different sizes, and with reasonably separated evolutionary trajectories, we investigate three issues: i) whether the distribution of connectivities changes between PPI subnetworks of essential and nonessential genes; ii) how gene conservation, measured both by the evolutionary retention index (ERI) and by evolutionary pressures, is related to the connectivity of the corresponding protein; iii) how PPI connectivities are modulated by evolutionary and functional relationships, as represented by the Clusters of Orthologous Genes (COGs). RESULTS We show that conservation, essentiality and functional specialisation of genes constrain the connectivity of the corresponding proteins in bacterial PPI networks. In particular, we isolated a core of highly connected proteins (connectivities k≥40), which is ubiquitous among the species considered here, though mostly visible in the degree distributions of bacteria with small genomes (less than 1000 genes). CONCLUSION The genes that support this highly connected core are conserved, essential and, in most cases, belong to the COG cluster J, related to ribosomal functions and the processing of genetic information.
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Affiliation(s)
- Maddalena Dilucca
- Dipartimento di Fisica, Sapienza University of Rome, 00185, Rome, Italy
| | - Giulio Cimini
- Dipartimento di Fisica, Tor Vergata University of Rome, 00133, Rome, Italy Istituto dei Sistemi Complessi CNR UoS, Rome, Italy
| | - Andrea Giansanti
- Dipartimento di Fisica, Sapienza University of Rome, 00185, Rome, Italy INFN Roma1 Unit, Rome, Italy
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Guzmán GI, Olson CA, Hefner Y, Phaneuf PV, Catoiu E, Crepaldi LB, Micas LG, Palsson BO, Feist AM. Reframing gene essentiality in terms of adaptive flexibility. BMC SYSTEMS BIOLOGY 2018; 12:143. [PMID: 30558585 PMCID: PMC6296033 DOI: 10.1186/s12918-018-0653-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 11/13/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Essentiality assays are important tools commonly utilized for the discovery of gene functions. Growth/no growth screens of single gene knockout strain collections are also often utilized to test the predictive power of genome-scale models. False positive predictions occur when computational analysis predicts a gene to be non-essential, however experimental screens deem the gene to be essential. One explanation for this inconsistency is that the model contains the wrong information, possibly an incorrectly annotated alternative pathway or isozyme reaction. Inconsistencies could also be attributed to experimental limitations, such as growth tests with arbitrary time cut-offs. The focus of this study was to resolve such inconsistencies to better understand isozyme activities and gene essentiality. RESULTS In this study, we explored the definition of conditional essentiality from a phenotypic and genomic perspective. Gene-deletion strains associated with false positive predictions of gene essentiality on defined minimal medium for Escherichia coli were targeted for extended growth tests followed by population sequencing and transcriptome analysis. Of the twenty false positive strains available and confirmed from the Keio single gene knock-out collection, 11 strains were shown to grow with longer incubation periods making these actual true positives. These strains grew reproducibly with a diverse range of growth phenotypes. The lag phase observed for these strains ranged from less than one day to more than 7 days. It was found that 9 out of 11 of the false positive strains that grew acquired mutations in at least one replicate experiment and the types of mutations ranged from SNPs and small indels associated with regulatory or metabolic elements to large regions of genome duplication. Comparison of the detected adaptive mutations, modeling predictions of alternate pathways and isozymes, and transcriptome analysis of KO strains suggested agreement for the observed growth phenotype for 6 out of the 9 cases where mutations were observed. CONCLUSIONS Longer-term growth experiments followed by whole genome sequencing and transcriptome analysis can provide a better understanding of conditional gene essentiality and mechanisms of adaptation to such perturbations. Compensatory mutations are largely reproducible mechanisms and are in agreement with genome-scale modeling predictions to loss of function gene deletion events.
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Affiliation(s)
- Gabriela I Guzmán
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA
| | - Connor A Olson
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA
| | - Ying Hefner
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA
| | - Patrick V Phaneuf
- Department of Bioinformatics and Systems Biology, University of California, San Diego, 92093, La Jolla, CA, USA
| | - Edward Catoiu
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA
| | - Lais B Crepaldi
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA.,Department of Chemical Engineering, University of Ribeirão Preto, São Paulo, Brazil
| | - Lucas Goldschmidt Micas
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA.,Department of Chemical and Petroleum Engineering, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.,Department of Pediatrics, University of California, San Diego, La Jolla, 92093, CA, USA
| | - Adam M Feist
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093, CA, USA. .,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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Martínez-Carranza E, Barajas H, Alcaraz LD, Servín-González L, Ponce-Soto GY, Soberón-Chávez G. Variability of Bacterial Essential Genes Among Closely Related Bacteria: The Case of Escherichia coli. Front Microbiol 2018; 9:1059. [PMID: 29910775 PMCID: PMC5992433 DOI: 10.3389/fmicb.2018.01059] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/04/2018] [Indexed: 11/23/2022] Open
Abstract
The definition of bacterial essential genes has been widely pursued using different approaches. Their study has impacted several fields of research such as synthetic biology, the construction of bacteria with minimal chromosomes, the search for new antibiotic targets, or the design of strains with biotechnological applications. Bacterial genomes are mosaics that only share a small subset of gene-sequences (core genome) even among members of the same species. It has been reported that the presence of essential genes is highly variable between closely related bacteria and even among members of the same species, due to the phenomenon known as “non-orthologous gene displacement” that refers to the coding for an essential function by genes with no sequence homology due to horizontal gene transfer (HGT). The existence of dormant forms among bacteria and the high incidence of HGT have been proposed to be driving forces of bacterial evolution, and they might have a role in the low level of conservation of essential genes among related bacteria by non-orthologous gene displacement, but this correlation has not been recognized. The aim of this mini-review is to give a brief overview of the approaches that have been taken to define and study essential genes, and the implications of non-orthologous gene displacement in bacterial evolution, focusing mainly in the case of Escherichia coli. To this end, we reviewed the available literature, and we searched for the presence of the essential genes defined by mutagenesis in the genomes of the 63 best-sequenced E. coli genomes that are available in NCBI database. We could not document specific cases of non-orthologous gene displacement among the E. coli strains analyzed, but we found that the quality of the genome-sequences in the database is not enough to make accurate predictions about the conservation of essential-genes among members of this bacterial species.
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Affiliation(s)
- Enrique Martínez-Carranza
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hugo Barajas
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis-David Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis Servín-González
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriel-Yaxal Ponce-Soto
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Dilucca M, Cimini G, Giansanti A. Essentiality, conservation, evolutionary pressure and codon bias in bacterial genomes. Gene 2018; 663:178-188. [PMID: 29678658 DOI: 10.1016/j.gene.2018.04.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/25/2018] [Accepted: 04/09/2018] [Indexed: 11/30/2022]
Abstract
Essential genes constitute the core of genes which cannot be mutated too much nor lost along the evolutionary history of a species. Natural selection is expected to be stricter on essential genes and on conserved (highly shared) genes, than on genes that are either nonessential or peculiar to a single or a few species. In order to further assess this expectation, we study here how essentiality of a gene is connected with its degree of conservation among several unrelated bacterial species, each one characterised by its own codon usage bias. Confirming previous results on E. coli, we show the existence of a universal exponential relation between gene essentiality and conservation in bacteria. Moreover, we show that, within each bacterial genome, there are at least two groups of functionally distinct genes, characterised by different levels of conservation and codon bias: i) a core of essential genes, mainly related to cellular information processing; ii) a set of less conserved nonessential genes with prevalent functions related to metabolism. In particular, the genes in the first group are more retained among species, are subject to a stronger purifying conservative selection and display a more limited repertoire of synonymous codons. The core of essential genes is close to the minimal bacterial genome, which is in the focus of recent studies in synthetic biology, though we confirm that orthologs of genes that are essential in one species are not necessarily essential in other species. We also list a set of highly shared genes which, reasonably, could constitute a reservoir of targets for new anti-microbial drugs.
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Affiliation(s)
- Maddalena Dilucca
- Dipartimento di Fisica, "Sapienza" University of Rome, Rome 00185, Italy.
| | - Giulio Cimini
- IMT School for Advanced Studies, Lucca 55100, Italy; Istituto dei Sistemi Complessi (ISC)-CNR, Rome 00185, Italy
| | - Andrea Giansanti
- Dipartimento di Fisica, "Sapienza" University of Rome, Rome 00185, Italy; INFN Roma1 Unit, Rome 00185, Italy
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Abstract
Gene essentiality is a founding concept of genetics with important implications in both fundamental and applied research. Multiple screens have been performed over the years in bacteria, yeasts, animals and more recently in human cells to identify essential genes. A mounting body of evidence suggests that gene essentiality, rather than being a static and binary property, is both context dependent and evolvable in all kingdoms of life. This concept of a non-absolute nature of gene essentiality changes our fundamental understanding of essential biological processes and could directly affect future treatment strategies for cancer and infectious diseases.
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Nandi S, Subramanian A, Sarkar RR. An integrative machine learning strategy for improved prediction of essential genes in Escherichia coli metabolism using flux-coupled features. MOLECULAR BIOSYSTEMS 2017; 13:1584-1596. [DOI: 10.1039/c7mb00234c] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We propose an integrated machine learning process to predict gene essentiality in Escherichia coli K-12 MG1655 metabolism that outperforms known methods.
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Affiliation(s)
- Sutanu Nandi
- Chemical Engineering and Process Development
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific & Innovative Research (AcSIR)
| | - Abhishek Subramanian
- Chemical Engineering and Process Development
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific & Innovative Research (AcSIR)
| | - Ram Rup Sarkar
- Chemical Engineering and Process Development
- CSIR-National Chemical Laboratory
- Pune-411008
- India
- Academy of Scientific & Innovative Research (AcSIR)
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Rani S, Koh HW, Rhee SK, Fujitani H, Park SJ. Detection and Diversity of the Nitrite Oxidoreductase Alpha Subunit (nxrA) Gene of Nitrospina in Marine Sediments. MICROBIAL ECOLOGY 2017; 73:111-122. [PMID: 27878347 DOI: 10.1007/s00248-016-0897-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/09/2016] [Indexed: 06/06/2023]
Abstract
Nitrite-oxidizing bacteria (NOB) are chemolithoautotrophs that catalyze the oxidation of nitrite to nitrate, which is the second step of aerobic nitrification. In marine ecosystems, Nitrospina is assumed to be a major contributor to nitrification. To date, two strains of Nitrospina have been isolated from marine environments. Despite their ecological relevance, their ecophysiology and environmental distribution are understudied owing to fastidious cultivation techniques and the lack of a sufficient functional gene marker. To estimate the abundance, diversity, and distribution of Nitrospina in various marine sediments, we used nxrA, which encodes the alpha subunit of nitrite oxidoreductase, as a functional and phylogenetic marker. We observed that Nitrospina diversity in polar sediments was significantly lower than that of non-polar samples. Moreover, nxrA-like sequences revealed an unexpected diversity of Nitrospina, with approximately 41,000 different sequences based on a 95% similarity cutoff from six marine sediments. We detected nxrA gene copy numbers of up to 3.57 × 104 per gram of marine sediment sample. The results of this study provide insight into the distribution and diversity of Nitrospina, which is fundamentally important for understanding their contribution to the nitrogen cycle in marine sediments.
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Affiliation(s)
- Sundas Rani
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, Republic of Korea
| | - Hyeon-Woo Koh
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, Republic of Korea
| | - Sung-Keun Rhee
- Department of Microbiology, Chungbuk National University, 1 Chungdae-ro, Cheongju, 28644, Republic of Korea
| | - Hirotsugu Fujitani
- Department of Life Science and Medical Bioscience, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
| | - Soo-Je Park
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, Republic of Korea.
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9
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Kristensen DM, Wolf YI, Koonin EV. ATGC database and ATGC-COGs: an updated resource for micro- and macro-evolutionary studies of prokaryotic genomes and protein family annotation. Nucleic Acids Res 2016; 45:D210-D218. [PMID: 28053163 PMCID: PMC5210634 DOI: 10.1093/nar/gkw934] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 11/14/2022] Open
Abstract
The Alignable Tight Genomic Clusters (ATGCs) database is a collection of closely related bacterial and archaeal genomes that provides several tools to aid research into evolutionary processes in the microbial world. Each ATGC is a taxonomy-independent cluster of 2 or more completely sequenced genomes that meet the objective criteria of a high degree of local gene order (synteny) and a small number of synonymous substitutions in the protein-coding genes. As such, each ATGC is suited for analysis of microevolutionary variations within a cohesive group of organisms (e.g. species), whereas the entire collection of ATGCs is useful for macroevolutionary studies. The ATGC database includes many forms of pre-computed data, in particular ATGC-COGs (Clusters of Orthologous Genes), multiple sequence alignments, a set of ‘index’ orthologs representing the most well-conserved members of each ATGC-COG, the phylogenetic tree of the organisms within each ATGC, etc. Although the ATGC database contains several million proteins from thousands of genomes organized into hundreds of clusters (roughly a 4-fold increase since the last version of the ATGC database), it is now built with completely automated methods and will be regularly updated following new releases of the NCBI RefSeq database. The ATGC database is hosted jointly at the University of Iowa at dmk-brain.ecn.uiowa.edu/ATGC/ and the NCBI at ftp.ncbi.nlm.nih.gov/pub/kristensen/ATGC/atgc_home.html.
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Affiliation(s)
- David M Kristensen
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA .,National Center for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, MD 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, MD 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, MD 20894, USA
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Alvarez-Ponce D, Sabater-Muñoz B, Toft C, Ruiz-González MX, Fares MA. Essentiality Is a Strong Determinant of Protein Rates of Evolution during Mutation Accumulation Experiments in Escherichia coli. Genome Biol Evol 2016; 8:2914-2927. [PMID: 27566759 PMCID: PMC5630975 DOI: 10.1093/gbe/evw205] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Neutral Theory of Molecular Evolution is considered the most powerful theory to understand the evolutionary behavior of proteins. One of the main predictions of this theory is that essential proteins should evolve slower than dispensable ones owing to increased selective constraints. Comparison of genomes of different species, however, has revealed only small differences between the rates of evolution of essential and nonessential proteins. In some analyses, these differences vanish once confounding factors are controlled for, whereas in other cases essentiality seems to have an independent, albeit small, effect. It has been argued that comparing relatively distant genomes may entail a number of limitations. For instance, many of the genes that are dispensable in controlled lab conditions may be essential in some of the conditions faced in nature. Moreover, essentiality can change during evolution, and rates of protein evolution are simultaneously shaped by a variety of factors, whose individual effects are difficult to isolate. Here, we conducted two parallel mutation accumulation experiments in Escherichia coli, during 5,500–5,750 generations, and compared the genomes at different points of the experiments. Our approach (a short-term experiment, under highly controlled conditions) enabled us to overcome many of the limitations of previous studies. We observed that essential proteins evolved substantially slower than nonessential ones during our experiments. Strikingly, rates of protein evolution were only moderately affected by expression level and protein length.
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Affiliation(s)
| | - Beatriz Sabater-Muñoz
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Valencia, Spain Department of Genetics, Smurfit Institute of Genetics, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Christina Toft
- Department of Genetics, University of Valencia, Valencia, Spain Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos (CSIC), Valencia, Spain
| | - Mario X Ruiz-González
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Valencia, Spain Current Address: Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, Proyecto Prometeo; Departamento de Ciencias Biológicas, Universidad Tócnica Particular de Loja, Loja, Ecuador
| | - Mario A Fares
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Valencia, Spain Department of Genetics, Smurfit Institute of Genetics, University of Dublin, Trinity College Dublin, Dublin, Ireland
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Ponce-de-Leon M, Calle-Espinosa J, Peretó J, Montero F. Consistency Analysis of Genome-Scale Models of Bacterial Metabolism: A Metamodel Approach. PLoS One 2015; 10:e0143626. [PMID: 26629901 PMCID: PMC4668087 DOI: 10.1371/journal.pone.0143626] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 11/06/2015] [Indexed: 01/10/2023] Open
Abstract
Genome-scale metabolic models usually contain inconsistencies that manifest as blocked reactions and gap metabolites. With the purpose to detect recurrent inconsistencies in metabolic models, a large-scale analysis was performed using a previously published dataset of 130 genome-scale models. The results showed that a large number of reactions (~22%) are blocked in all the models where they are present. To unravel the nature of such inconsistencies a metamodel was construed by joining the 130 models in a single network. This metamodel was manually curated using the unconnected modules approach, and then, it was used as a reference network to perform a gap-filling on each individual genome-scale model. Finally, a set of 36 models that had not been considered during the construction of the metamodel was used, as a proof of concept, to extend the metamodel with new biochemical information, and to assess its impact on gap-filling results. The analysis performed on the metamodel allowed to conclude: 1) the recurrent inconsistencies found in the models were already present in the metabolic database used during the reconstructions process; 2) the presence of inconsistencies in a metabolic database can be propagated to the reconstructed models; 3) there are reactions not manifested as blocked which are active as a consequence of some classes of artifacts, and; 4) the results of an automatic gap-filling are highly dependent on the consistency and completeness of the metamodel or metabolic database used as the reference network. In conclusion the consistency analysis should be applied to metabolic databases in order to detect and fill gaps as well as to detect and remove artifacts and redundant information.
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Affiliation(s)
- Miguel Ponce-de-Leon
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain
- * E-mail:
| | - Jorge Calle-Espinosa
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain
| | - Juli Peretó
- Departament de Bioquímica i Biologia Molecular and Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, C/José Beltrán 2, Paterna 46980, Spain
| | - Francisco Montero
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain
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