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Gnanagobal H, Cao T, Hossain A, Vasquez I, Chakraborty S, Chukwu-Osazuwa J, Boyce D, Espinoza MJ, García-Angulo VA, Santander J. Role of riboflavin biosynthesis gene duplication and transporter in Aeromonas salmonicida virulence in marine teleost fish. Virulence 2023; 14:2187025. [PMID: 36895132 PMCID: PMC10012899 DOI: 10.1080/21505594.2023.2187025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
Active flavins derived from riboflavin (vitamin B2) are essential for life. Bacteria biosynthesize riboflavin or scavenge it through uptake systems, and both mechanisms may be present. Because of riboflavin's critical importance, the redundancy of riboflavin biosynthetic pathway (RBP) genes might be present. Aeromonas salmonicida, the aetiological agent of furunculosis, is a pathogen of freshwater and marine fish, and its riboflavin pathways have not been studied. This study characterized the A. salmonicida riboflavin provision pathways. Homology search and transcriptional orchestration analysis showed that A. salmonicida has a main riboflavin biosynthetic operon that includes ribD, ribE1, ribBA, and ribH genes. Outside the main operon, putative duplicated genes ribA, ribB and ribE, and a ribN riboflavin importer encoding gene, were found. Monocistronic mRNA ribA, ribB and ribE2 encode for their corresponding functional riboflavin biosynthetic enzyme. While the product of ribBA conserved the RibB function, it lacked the RibA function. Likewise, ribN encodes a functional riboflavin importer. Transcriptomics analysis indicated that external riboflavin affected the expression of a relatively small number of genes, including a few involved in iron metabolism. ribB was downregulated in response to external riboflavin, suggesting negative feedback. Deletion of ribA, ribB and ribE1 showed that these genes are required for A. salmonicida riboflavin biosynthesis and virulence in Atlantic lumpfish (Cyclopterus lumpus). A. salmonicida riboflavin auxotrophic attenuated mutants conferred low protection to lumpfish against virulent A. salmonicida. Overall, A. salmonicida has multiple riboflavin endowment forms, and duplicated riboflavin provision genes are critical for A. salmonicida infection.
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Affiliation(s)
- Hajarooba Gnanagobal
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Trung Cao
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ahmed Hossain
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ignacio Vasquez
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Setu Chakraborty
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Joy Chukwu-Osazuwa
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Danny Boyce
- The Dr. Joe Brown Aquatic Research Building (JBARB), Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Canada
| | - María Jesus Espinoza
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Javier Santander
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
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Paredes-Amaya CC, Ulloa MT, García-Angulo VA. Fierce poison to others: the phenomenon of bacterial dependence on antibiotics. J Biomed Sci 2023; 30:67. [PMID: 37574554 PMCID: PMC10424368 DOI: 10.1186/s12929-023-00963-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.
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Affiliation(s)
- Claudia C Paredes-Amaya
- Microbiology Department, Escuela de Ciencias Básicas, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | - María Teresa Ulloa
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile
- Vertebral I+D+i - Corporation for Assistance for Burned Children (Coaniquem), Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile.
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Lozano Aguirre LF, Salazar JC, Vásquez JI, García-Angulo VA. Interdependency of regulatory effects of iron and riboflavin in the foodborne pathogen Shigella flexneri determined by integral transcriptomics. PeerJ 2020; 8:e9553. [PMID: 32983629 PMCID: PMC7500357 DOI: 10.7717/peerj.9553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/24/2020] [Indexed: 11/24/2022] Open
Abstract
Shigella flexneri is the causative agent of dysentery. For pathogens, iron is a critical micronutrient as its bioavailability is usually low in bacterial niches. This metal is involved in critical physiological processes mainly as a component of important metabolic molecules involved in redox reactions. Usually bacteria respond to fluctuations in iron availability to regulate iron acquisition and other iron-related functions. Recently the close metabolic feedback between iron and riboflavin, another pivotal biological redox agent, began to draw attention in bacteria. This is a widespread biological phenomenon, partly characterized by the coordination of regulatory responses to iron and riboflavin, probably owed to the involvement of these cofactors in common processes. Nonetheless, no systematic analyses to determine the extent of this regulatory effect have been performed in any species. Here, the transcriptomics responses to iron, riboflavin, iron in the presence of riboflavin and riboflavin in the presence of iron were assessed and compared in S. flexneri. The riboflavin regulon had a 43% overlap with the iron regulon. Notably, the presence of riboflavin highly increased the number of iron-responsive genes. Reciprocally, iron drastically changed the pool of riboflavin-responsive genes. Gene ontology (GO) functional terms enrichment analysis showed that biological processes were distinctively enriched for each subgroup of responsive genes. Among the biological processes regulated by iron and riboflavin were iron uptake, amino acids metabolism and electron transfer for ATP synthesis. Thus, iron and riboflavin highly affect the transcriptomics responses induced by each other in S. flexneri. GO terms analysis suggests that iron and riboflavin coordinately regulate specific physiological functions involving redox metabolism.
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Affiliation(s)
- Luis Fernando Lozano Aguirre
- Unidad de Análisis Bioinformáticos, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - José Ignacio Vásquez
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John, Canada
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Sepúlveda-Cisternas I, Lozano Aguirre L, Fuentes Flores A, Vásquez Solis de Ovando I, García-Angulo VA. Transcriptomics reveals a cross-modulatory effect between riboflavin and iron and outlines responses to riboflavin biosynthesis and uptake in Vibrio cholerae. Sci Rep 2018; 8:3149. [PMID: 29453341 PMCID: PMC5816637 DOI: 10.1038/s41598-018-21302-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/31/2018] [Indexed: 12/19/2022] Open
Abstract
Vibrio cholerae, a pandemic diarrheagenic bacterium, is able to synthesize the essential vitamin riboflavin through the riboflavin biosynthetic pathway (RBP) and also to internalize it through the RibN importer. In bacteria, the way riboflavin biosynthesis and uptake functions correlate is unclear. To gain insights into the role of the riboflavin provision pathways in the physiology of V. cholerae, we analyzed the transcriptomics response to extracellular riboflavin and to deletions of ribD (RBP-deficient strain) or ribN. Many riboflavin-responsive genes were previously reported to belong to the iron regulon, including various iron uptake genes. Real time PCR analysis confirmed this effect and further documented that reciprocally, iron regulates RBP and ribN genes in a riboflavin-dependent way. A subset of genes were responding to both ribD and ribN deletions. However, in the subset of genes specifically affected in the ∆ribD strain, the functional terms protein folding and oxidation reduction process were enriched, as determined by a Gene Ontology analysis. In the gene subset specifically affected in the ∆ribN strain, the cytochrome complex assembly functional term was enriched. Results suggest that iron and riboflavin interrelate to regulate its respective provision genes and that both common and specific effects of biosynthesized and internalized riboflavin exist.
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Affiliation(s)
- Ignacio Sepúlveda-Cisternas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Escuela de Biotecnología, Universidad Mayor, Campus Huechuraba, Santiago, Chile
| | - Luis Lozano Aguirre
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, campus Chamilpa Cuernavaca, Morelos, Mexico
| | - Andrés Fuentes Flores
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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Fuentes Flores A, Sepúlveda Cisternas I, Vásquez Solis de Ovando JI, Torres A, García-Angulo VA. Contribution of riboflavin supply pathways to Vibrio cholerae in different environments. Gut Pathog 2017; 9:64. [PMID: 29163672 PMCID: PMC5686954 DOI: 10.1186/s13099-017-0214-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/06/2017] [Indexed: 12/15/2022] Open
Abstract
Background The waterborne diarrheagenic bacterium Vibrio cholerae, cause of the pandemic cholera disease, thrives in a variety of environments ranging from estuarine waters to the human intestinal tract. This species has two ways to obtain the essential micronutrient riboflavin, de novo biosynthesis and environmental uptake through the RibN importer. The way these functions interrelate to fulfill riboflavin needs in different conditions in this species is unknown. Results This study analyzed the contributions of riboflavin biosynthesis and transport to the culturability of Vibrio cholerae in river and seawater in vitro and in the Caenorhabditis elegans nematode host model. Elimination of the ribD riboflavin biosynthetic gene renders the bacteria riboflavin-auxotrophic, while a ribN mutant strain has no growth defect in minimal media. When growing in river water, deletion of ribD causes an impairment in culturability. In this condition, the ∆ribN strain has a defect to compete against a wild type strain but outcompetes the ∆ribD strain. The latter effect is inverted by the addition of riboflavin to the water. In contrast, growth in seawater causes a loss in culturability independent of riboflavin biosynthesis or transport. In the C. elegans model, only the ∆ribD strain is attenuated. Conclusion Results indicate that while riboflavin biosynthesis seems to outweigh riboflavin uptake, the latter may still provide a selective advantage to V. cholerae in some environments. Electronic supplementary material The online version of this article (10.1186/s13099-017-0214-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrés Fuentes Flores
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Ignacio Sepúlveda Cisternas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Escuela de Biotecnología, Universidad Mayor, Campus Huechuraba, Santiago, Chile
| | | | - Alexia Torres
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Víctor Antonio García-Angulo
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Facultad de Medicina Norte, Pabellón L. Santiago de Chile, ZIP 8380453 Santiago, Chile
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Abstract
Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.
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Affiliation(s)
- Víctor Antonio García-Angulo
- a Microbiology and Mycology Program, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile , Santiago , Chile
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Gutiérrez-Preciado A, Torres AG, Merino E, Bonomi HR, Goldbaum FA, García-Angulo VA. Extensive Identification of Bacterial Riboflavin Transporters and Their Distribution across Bacterial Species. PLoS One 2015; 10:e0126124. [PMID: 25938806 PMCID: PMC4418817 DOI: 10.1371/journal.pone.0126124] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/29/2015] [Indexed: 11/18/2022] Open
Abstract
Riboflavin, the precursor for the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide, is an essential metabolite in all organisms. While the functions for de novo riboflavin biosynthesis and riboflavin import may coexist in bacteria, the extent of this co-occurrence is undetermined. The RibM, RibN, RfuABCD and the energy-coupling factor-RibU bacterial riboflavin transporters have been experimentally characterized. In addition, ImpX, RfnT and RibXY are proposed as riboflavin transporters based on positional clustering with riboflavin biosynthetic pathway (RBP) genes or conservation of the FMN riboswitch regulatory element. Here, we searched for the FMN riboswitch in bacterial genomes to identify genes encoding riboflavin transporters and assessed their distribution among bacteria. Two new putative riboflavin transporters were identified: RibZ in Clostridium and RibV in Mesoplasma florum. Trans-complementation of an Escherichia coli riboflavin auxotroph strain confirmed the riboflavin transport activity of RibZ from Clostridium difficile, RibXY from Chloroflexus aurantiacus, ImpX from Fusobacterium nucleatum and RfnT from Ochrobactrum anthropi. The analysis of the genomic distribution of all known bacterial riboflavin transporters revealed that most occur in species possessing the RBP and that some bacteria may even encode functional riboflavin transporters from two different families. Our results indicate that some species possess ancestral riboflavin transporters, while others possess transporters that appear to have evolved recently. Moreover, our data suggest that unidentified riboflavin transporters also exist. The present study doubles the number of experimentally characterized riboflavin transporters and suggests a specific, non-accessory role for these proteins in riboflavin-prototrophic bacteria.
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Affiliation(s)
- Ana Gutiérrez-Preciado
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alfredo Gabriel Torres
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | | | | | - Víctor Antonio García-Angulo
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Centro de Genómica y Bioinformática, Universidad Mayor, Campus Huechuraba, Santiago, Chile
- * E-mail:
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