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González-Torres B, González-Gómez JP, Ramírez K, Castro-del Campo N, González-López I, Garrido-Palazuelos LI, Chaidez C, Medrano-Félix JA. Population structure of the Salmonella enterica serotype Oranienburg reveals similar virulence, regardless of isolation years and sources. Gene 2023; 851:146966. [DOI: 10.1016/j.gene.2022.146966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/26/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022]
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Ray S, Pandey NK, Kushwaha GS, Das S, Ganguly AK, Vashi N, Kumar D, Suar M, Bhavesh NS. Structural investigation on SPI-6 associated Salmonella Typhimurium VirG-like stress protein that promotes pathogen survival in macrophages. Protein Sci 2022; 31:835-849. [PMID: 34997791 DOI: 10.1002/pro.4272] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 11/10/2022]
Abstract
Enteric microbial pathogenesis, remarkably a complex process, is achieved by virulence factors encoded by genes located within regions of the bacterial genome termed pathogenicity islands. Salmonella pathogenicity islands (SPI) encodes proteins, that are essential virulence determinants for pathogen colonization and virulence. In addition to the well-characterized SPI-1 and SPI-2 proteins, which are required for bacterial invasion and intracellular replication, respectively, SPI-6 (formerly known as Salmonella enterica centisome 7 island; SCI) encoding proteins are also known to play pivotal role in Salmonella pathogenesis. However, the underlying molecular mechanism of these proteins remained elusive. To gain molecular insights into SPI-6 associated proteins, in this study, a SPI-6 Salmonella Typhimurium VirG-like protein (STV) is characterized using interdisciplinary experimental approaches including X-ray crystallography, NMR spectroscopy, infection assays, and mice model. The high-resolution crystal structure, determined by the single-wavelength anomalous dispersion (SAD) method, reveals that STV belongs to the LTxxQ motif family. Solution-state NMR spectroscopy studies reveal that STV form a dimer involving interconnected helices. Interestingly, functional studies shows that STV influence pathogen persistence inside macrophages in vitro at later stages of infection. Altogether, our findings suggest that STV, a member of the LTxxQ stress protein family, modulates bacterial survival mechanism in macrophages through SPI-1 and SPI-2 genes, respectively. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shilpa Ray
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India
| | - Nishant Kumar Pandey
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India.,Transcription Regulation group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
| | - Gajraj Singh Kushwaha
- Transcription Regulation group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India.,KIIT-Technology Business Incubator, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India
| | - Susmita Das
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India
| | - Akshay Kumar Ganguly
- Transcription Regulation group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
| | - Nimi Vashi
- Cellular Immunology group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
| | - Dhiraj Kumar
- Cellular Immunology group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
| | - Mrutyunjay Suar
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India.,KIIT-Technology Business Incubator, Kalinga Institute of Industrial Technology (KIIT), Deemed to be university, Bhubaneswar, India
| | - Neel Sarovar Bhavesh
- Transcription Regulation group, International Centre of Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, India
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Das S, Ray S, Arunima A, Sahu B, Suar M. A ROD9 island encoded gene in Salmonella Enteritidis plays an important role in acid tolerance response and helps in systemic infection in mice. Virulence 2020; 11:247-259. [PMID: 32116124 PMCID: PMC7051147 DOI: 10.1080/21505594.2020.1733203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 10/31/2022] Open
Abstract
Salmonella, like other pathogenic bacteria has undergone multiple genomic alterations to adapt itself into specific host environments executing varied degrees of virulence through evolution. Such variations in genome content have been assumed to lead the closely related non-typhoidal serovars, S. Enteritidis, and S. Typhimurium to exhibit Type Three Secretion System -2 (T3SS-2) based diverse colonization and inflammation kinetics. Mutually exclusive genes present in either of the serovars are recently being studied and in our currentwork, we focused on a particular island ROD9, present in S. Enteritidis but not in S. Typhimurium. Earlier reports have identified a few genes from this island to be responsible for virulence in vitro as well as in vivo. In this study, we have identified another gene, SEN1008 from the same island encoding a hypothetical protein to be a potential virulence determinant showing systemic attenuation upon mutation in C57BL/6 mice infection model. The isogenic mutant strain displayed reduced adhesion to epithelial cells in vitro as well as was highly immotile. It was also deficient in intracellular replication in vitro, with a highly suppressed SPI-2and failed to cause acute colitis at 72-h p.i.in vivo. Moreover, on acid exposure, SEN1008 showed 17 folds and 2 fold up-regulations during adaptation and challenge phases,respectively and ΔSEN1008 failed to survive during ATR assay, indicating its role under acid stress. Together, our findings suggested ΔSEN1008 to be significantly attenuated and we propose this gene to be a potent factor responsible for S. Enteritidis pathogenesis.
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Affiliation(s)
- Susmita Das
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | | | - Bikash Sahu
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, India
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Ray S, Das S, Panda PK, Suar M. Identification of a new alanine racemase in Salmonella Enteritidis and its contribution to pathogenesis. Gut Pathog 2018; 10:30. [PMID: 30008809 PMCID: PMC6040060 DOI: 10.1186/s13099-018-0257-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/03/2018] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Non-typhoidal Salmonella (NTS) infections caused primarily by S. Enteritidis and S. Typhimurium particularly in immunocompromised hosts have accounted for a large percentage of fatalities in developed nations. Antibiotics have revolutionized the cure of enteric infections but have also led to the rapid emergence of pathogen resistance. New powerful therapeutics involving metabolic enzymes are expected to be potential targets for combating microbial infections and ensuring effective health management. Therefore, the need for new antimicrobials to fight such health emergencies is paramount. Enteric bacteria successfully evade the gut and colonize their hosts through specialized virulence strategies. An important player, alanine racemase is a key enzyme facilitating bacterial survival. RESULTS This study aims at understanding the contribution of alanine racemase genes alr, dadX and SEN3897 to Salmonella survival in vitro and in vivo. We have shown SEN3897 to function as a unique alanine racemase in S. Enteritidis which displayed essential alanine racemase activity. Interestingly, the sole presence of this gene in alr dadX double mutant showed a strict dependence on d-alanine supplementation both in vitro and in vivo. However, Alr complementation in d-alanine auxotrophic strain restored the alanine racemase deficiency. The Km and Vmax of SEN3897 was 89.15 ± 10.2 mM, 400 ± 25.6 µmol/(min mg) for l-alanine and 35 ± 6 mM, 132.5 ± 11.3 µmol/(min mg) for d-alanine, respectively. In vitro assays for invasion and survival as well as in vivo virulence assays involving SEN3897 mutant showed attenuated phenotypes. Further, this study also showed attenuation of d-alanine auxotrophic strain in vivo for the development of potential targets against Salmonella that can be investigated further. CONCLUSION This study identified a third alanine racemase gene unique in S. Enteritidis which had a potential effect on survival and pathogenesis in vitro and in vivo. Our results also confirmed that SEN3897 by itself wasn't able to rescue d-alanine auxotrophy in S. Enteritidis which further contributed to its virulence properties.
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Affiliation(s)
- Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha India
| | - Susmita Das
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha India
| | | | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha India
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Zha H, Jeffs A, Dong Y, Lewis G. Potential virulence factors of bacteria associated with tail fan necrosis in the spiny lobster, Jasus edwardsii. JOURNAL OF FISH DISEASES 2018; 41:817-828. [PMID: 29473647 DOI: 10.1111/jfd.12791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 06/08/2023]
Abstract
Tail fan necrosis (TFN) is a common condition found in commercially exploited spiny lobsters that greatly diminishes their commercial value. Bacteria possessing proteolytic, chitinolytic and lipolytic capabilities were associated with TFN in spiny lobsters, Jasus edwardsii. In this study, 69 bacterial isolates exhibiting all the three enzymatic capabilities from the haemolymph and tail fans of J. edwardsii with and without TFN were further characterized and compared, including morphology, biofilm formation, antimicrobial activity, antimicrobial resistance, and production of siderophores, melanin and ammonia. The genomic patterns of the most common Vibrio crassostreae isolates were also compared between TFN-affected and unaffected lobsters. Biofilm formation was stronger in bacterial isolates from both haemolymph and tail fans of TFN-affected lobsters compared to those from the unaffected lobsters, while melanin production and siderophore production were stronger in the isolates from tail fans of lobsters with TFN. By contrast, the other characteristics of isolates were similar in lobsters with and without TFN. The Vib. crassostreae isolates from the affected lobsters had similar genomic patterns. Overall, the results indicate that in addition to proteolytic, chitinolytic and lipolytic activities, the bacteria associated with TFN commonly have enhanced activity of important virulence factors, including biofilm formation, melanin production and siderophore production.
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Affiliation(s)
- H Zha
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
| | - A Jeffs
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
| | - Y Dong
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - G Lewis
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Das S, Ray S, Ryan D, Sahu B, Suar M. Identification of a novel gene in ROD9 island of Salmonella Enteritidis involved in the alteration of virulence-associated genes expression. Virulence 2018; 9:348-362. [PMID: 29130383 PMCID: PMC5955183 DOI: 10.1080/21505594.2017.1392428] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 01/10/2023] Open
Abstract
Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis), one of the causative agents for non-typhoidal gastrointestinal diseases in humans is an intracellular bacterium and mechanism for its invasion into host cells is critical to cause infection. The virulence of the pathogen is explained by the expression of genes located on its pathogenicity islands, mostly encoded under SPI-1 and SPI-2. However, S. Typhimurium SL1344, despite sharing ∼98% of its genome with S. Enteritidis P125109, lacks few regions of differences (ROD) that are hypothesized to impart virulence potential to S. Enteritidis. In this study, we created different mutants in the ROD9 island of S. Enteritidis, also referred as SPI-19 and identified a novel locus, SEN1005, encoding a hypothetical protein that is involved in its pathogenesis. ΔSEN1005 displayed significantly reduced entry into cultured epithelial cells as well as uptake by macrophages and failed to cause acute colitis in C57BL/6 mice at day 3 post-infection (p.i.). Additionally, the global transcriptome analysis revealed a highly repressed SPI-1 and other down-regulated genes responsible for flagellar assembly, chemotaxis and motility in the mutant which correlated with decreased invasion and abated inflammation as compared to the wild-type. Therefore, our findings revealed that ΔSEN1005 was attenuated in vitro as well as in vivo and we propose this hypothetical protein to play a role in altering the expression of genes involved in Salmonella virulence.
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Affiliation(s)
- Susmita Das
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha
| | - Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha
| | - Daniel Ryan
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha
| | - Bikash Sahu
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha
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