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Ozdemir E, Abdelhamed H, Ozdemir O, Lawrence M, Karsi A. Development of Bioluminescent Virulent Aeromonas hydrophila for Understanding Pathogenicity. Pathogens 2023; 12:pathogens12050670. [PMID: 37242340 DOI: 10.3390/pathogens12050670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/25/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
Virulent Aeromonas hydrophila (vAh) strains that cause motile Aeromonas septicemia (MAS) in farmed channel catfish (Ictalurus punctatus) have been an important problem for more than a decade. However, the routes of infection of vAh in catfish are not well understood. Therefore, it is critical to study the pathogenicity of vAh in catfish. To this goal, a new bioluminescence expression plasmid (pAKgfplux3) with the chloramphenicol acetyltransferase (cat) gene was constructed and mobilized into vAh strain ML09-119, yielding bioluminescent vAh (BvAh). After determining optimal chloramphenicol concentration, plasmid stability, bacteria number-bioluminescence relationship, and growth kinetics, the catfish were challenged with BvAh, and bioluminescent imaging (BLI) was conducted. Results showed that 5 to 10 µg/mL chloramphenicol was suitable for stable bioluminescence expression in vAh, with some growth reduction. In the absence of chloramphenicol, vAh could not maintain pAKgfplux3 stably, with the half-life being 16 h. Intraperitoneal injection, immersion, and modified immersion (adipose fin clipping) challenges of catfish with BvAh and BLI showed that MAS progressed faster in the injection group, followed by the modified immersion and immersion groups. BvAh was detected around the anterior mouth, barbels, fin bases, fin epithelia, injured skin areas, and gills after experimental challenges. BLI revealed that skin breaks and gills are potential attachment and entry portals for vAh. Once vAh breaches the skin or epithelial surfaces, it can cause a systemic infection rapidly, spreading to all internal organs. To our best knowledge, this is the first study that reports the development of a bioluminescent vAh and provides visual evidence for catfish-vAh interactions. Findings are expected to provide a better understanding of vAh pathogenicity in catfish.
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Affiliation(s)
- Eda Ozdemir
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Ozan Ozdemir
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Mark Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
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Ibrahim I, Abdelhamed H, Baumgartner W, Wills RW, Awadin W, Elbegawy M, Lawrence ML, Karsi A. Pathological and Ultrastructural Characterization of an Edwardsiella ictaluri Triple hemR Mutant. JOURNAL OF AQUATIC ANIMAL HEALTH 2022; 34:116-133. [PMID: 35590426 DOI: 10.1002/aah.10154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/10/2022] [Accepted: 03/27/2022] [Indexed: 06/15/2023]
Abstract
Enteric septicemia of catfish, which is caused by Edwardsiella ictaluri, is detrimental to farmed Channel Catfish Ictalurus punctatus. The hemin receptor HemR is involved in binding and uptake of heme into bacteria. Here, we explored pathological and ultrastructural changes in catfish fry that were immunized with a triple hemR mutant of E. ictaluri and challenged with wild-type E. ictaluri (EiWT) 28 d after immunization. Following immunization, pathological changes in the triple hemR-immunized fry were less severe compared to the EiWT-exposed control fry. Widely disseminated bacteria and severe necrosis in most organs, especially the kidney and spleen, were detected in both groups at days 4, 5, and 6. Multifocal granulomatous encephalitis with bacteria was seen in hemR-immunized fry at days 21 and 28 and in EiWT-exposed control fry at day 14. Phagocytic cells in the kidney and spleen of EiWT-exposed control fry contained more replicating bacteria compared to hemR-immunized fry. During the EiWT challenge of immunized fry, a robust immune response was observed in the triple hemR-immunized fry compared to the sham-vaccinated group. Many activated phagocytic cells were detected in the kidney and spleen with fragmented or no bacteria in the triple hemR-immunized fry. Our data suggested that virulence of triple hemR was lower and the onset of the lesions was delayed compared to EiWT. Additionally, triple hemR-immunized fry could mount an immune response and had milder lesions compared to the sham control after EiWT exposure.
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Affiliation(s)
- Iman Ibrahim
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Wes Baumgartner
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Robert W Wills
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Walaa Awadin
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Mahmoud Elbegawy
- Department of Pathology, Faculty of Veterinary Medicine, Benisuef University, Benisuef, Egypt
| | - Mark L Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
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Zhao H, Wang Q, Zhao H, Chen C. Transcriptome profiles revealed high- and low-salinity water altered gill homeostasis in half-smooth tongue sole (Cynoglossus semilaevis). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2022; 42:100989. [PMID: 35421665 DOI: 10.1016/j.cbd.2022.100989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/27/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
Salinity is an important environmental factor that affects fish growth, development, and reproduction. As euryhaline fish, half-smooth tongue sole (Cynoglossus semilaevis) are a suitable species for deciphering the salinity adaptation mechanism of fish; however, the molecular mechanisms underlying low- and high-salinity responses remain unclear. In this study, RNA-seq was applied to characterize the genes and regulatory pathways involved in C. semilaevis gill responses to high- (32 ppt), low- (8 ppt), and control-salinity (24 ppt) water. Gills were rich in mitochondria-rich cells (MRCs) in high salinity. Compared with control, 2137 and 218 differentially expressed genes (DEGs) were identified in low and high salinity, respectively. The enriched functions of most DEGs were metabolism, ion transport, regulation of cell cycle, and immune response. The DEGs involved in oxidative phosphorylation, citrate cycle, and fatty acid metabolism were down-regulated in low salinity. For ion transport, high and low salinity significantly altered the expressions of prlr, ca12, and cftr. In cell cycle arrest and cellular repair, gadd45b, igfbp5, and igfbp2 were significantly upregulated in high and low salinity. For immune response, il10, il34, il12b, and crp increased in high and low salinity. Our findings suggested that alterations in material and energy metabolism, ions transport, cell cycle arrest, cellular repair, and immune response, are required to maintain C. semilaevis gill homeostasis under high and low salinity. This study provides insight into the divergence of C. semilaevis osmoregulation mechanisms acclimating to high and low salinity, which will serve as reference for the healthy culture of C. semilaevis.
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Affiliation(s)
- Huiyan Zhao
- Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, Tianjin 300392, China; College of Fisheries, Tianjin Agricultural University, Tianjin 300392, China
| | - Qingkui Wang
- Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, Tianjin 300392, China; College of Fisheries, Tianjin Agricultural University, Tianjin 300392, China.
| | - Honghao Zhao
- Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, Tianjin 300392, China; College of Fisheries, Tianjin Agricultural University, Tianjin 300392, China
| | - Chengxun Chen
- Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, Tianjin 300392, China; College of Fisheries, Tianjin Agricultural University, Tianjin 300392, China
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Kalindamar S, Abdelhamed H, Kordon AO, Pinchuk LM, Karsi A. Hemolysin Co-regulated Family Proteins Hcp1 and Hcp2 Contribute to Edwardsiella ictaluri Pathogenesis. Front Vet Sci 2021; 8:681609. [PMID: 34150898 PMCID: PMC8207204 DOI: 10.3389/fvets.2021.681609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/07/2021] [Indexed: 01/22/2023] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen causing enteric septicemia of catfish (ESC), a devastating disease resulting in significant economic losses in the U.S. catfish industry. Bacterial secretion systems are involved in many bacteria's virulence, and Type VI Secretion System (T6SS) is a critical apparatus utilized by several pathogenic Gram-negative bacteria. E. ictaluri strain 93-146 genome has a complete T6SS operon with 16 genes, but the roles of these genes are still not explored. In this research, we aimed to understand the roles of two hemolysin co-regulated family proteins, Hcp1 (EvpC) and Hcp2. To achieve this goal, single and double E. ictaluri mutants (EiΔevpC, EiΔhcp2, and EiΔevpCΔhcp2) were generated and characterized. Catfish peritoneal macrophages were able to kill EiΔhcp2 better than EiΔevpC, EiΔevpCΔhcp2, and E. ictaluri wild-type (EiWT). The attachment of EiΔhcp2 and EiΔevpCΔhcp2 to ovary cells significantly decreased compared to EiWT whereas the cell invasion rates of these mutants were the same as that of EiWT. Mutants exposed to normal catfish serum in vitro showed serum resistance. The fish challenges demonstrated that EiΔevpC and EiΔevpCΔhcp2 were attenuated completely and provided excellent protection against EiWT infection in catfish fingerlings. Interestingly, EiΔhcp2 caused higher mortality than that of EiWT in catfish fingerlings, and severe clinical signs were observed. Although fry were more susceptible to vaccination with EiΔevpC and EiΔevpCΔhcp2, their attenuation and protection were significantly higher compared to EiWT and sham groups, respectively. Taken together, our data indicated that evpC (hcp1) is involved in E. ictaluri virulence in catfish while hcp2 is involved in adhesion to epithelial cells and survival inside catfish macrophages.
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Affiliation(s)
- Safak Kalindamar
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Ordu University, Ordu, Turkey
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Adef O Kordon
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Lesya M Pinchuk
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
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Functional Identification of Serine Hydroxymethyltransferase as a Key Gene Involved in Lysostaphin Resistance and Virulence Potential of Staphylococcus aureus Strains. Int J Mol Sci 2020; 21:ijms21239135. [PMID: 33266291 PMCID: PMC7731198 DOI: 10.3390/ijms21239135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/22/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
Gaining an insight into the mechanism underlying antimicrobial-resistance development in Staphylococcus aureus is crucial for identifying effective antimicrobials. We isolated S. aureus sequence type 72 from a patient in whom the S. aureus infection was highly resistant to various antibiotics and lysostaphin, but no known resistance mechanisms could explain the mechanism of lysostaphin resistance. Genome-sequencing followed by subtractive and functional genomics revealed that serine hydroxymethyltransferase (glyA or shmT gene) plays a key role in lysostaphin resistance. Serine hydroxymethyltransferase (SHMT) is indispensable for the one-carbon metabolism of serine/glycine interconversion and is linked to folate metabolism. Functional studies revealed the involvement of SHMT in lysostaphin resistance, as ΔshmT was susceptible to the lysostaphin, while complementation of the knockout expressing shmT restored resistance against lysostaphin. In addition, the ΔshmT showed reduced virulence under in vitro (mammalian cell lines infection) and in vivo (wax-worm infection) models. The SHMT inhibitor, serine hydroxymethyltransferase inhibitor 1 (SHIN1), protected the 50% of the wax-worm infected with wild type S. aureus. These results suggest SHMT is relevant to the extreme susceptibility to lysostaphin and the host immune system. Thus, the current study established that SHMT plays a key role in lysostaphin resistance development and in determining the virulence potential of multiple drug-resistant S. aureus.
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Edrees A, Abdelhamed H, Nho SW, Ozdemir O, Karsi A, Essa M, Lawrence ML. An Edwardsiella piscicida esaS mutant reveals contribution to virulence and vaccine potential. Microb Pathog 2020; 143:104108. [PMID: 32145320 DOI: 10.1016/j.micpath.2020.104108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 02/23/2020] [Accepted: 02/27/2020] [Indexed: 11/15/2022]
Abstract
Edwardsiella piscicida is a Gram-negative pathogen that causes disease in diverse aquatic organisms. The disease leads to extensive losses in commercial aquaculture species, including farmed U.S. catfish. The type III secretion system (T3SS) often contributes to virulence of Gram-negative bacteria. The E. piscicida esaS gene encodes a predicted T3SS export apparatus protein. In the current study, an E. piscicida esaS mutant was constructed and characterized to increase our understanding of the role of T3SS in E. piscicida virulence. Deletion of esaS did not significantly affect biofilm formation and hemolytic activity of E. piscicida, but it had significant effects on expression of hemolysis and T3SS effector genes during biofilm growth. EpΔesaS showed significantly (P < 0.05) reduced virulence in catfish compared to the parent strain. No mortalities occurred in fish infected with EpΔesaS at 6.3 × 105 and 1.26 × 106 CFU/fish compared to 26% mortality in fish infected with wild-type E. piscicida at 7.5 × 105 CFU/fish. Bioluminescence imaging indicated that EpΔesaS invades catfish and colonizes for a short period in the organs. Furthermore, catfish immunized with EpΔesaS at 6.3 × 105 and 1.26 × 106 CFU provided 47% and 87% relative percent survival, respectively. These findings demonstrated that esaS plays a role in E. piscicida virulence, and the deletion mutant has vaccine potential for protection against wild-type E. piscicida infection.
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Affiliation(s)
- Asmaa Edrees
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Seong-Won Nho
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Ozan Ozdemir
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Manal Essa
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Mark L Lawrence
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt.
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Kalindamar S, Lu J, Abdelhamed H, Tekedar HC, Lawrence ML, Karsi A. Transposon mutagenesis and identification of mutated genes in growth-delayed Edwardsiella ictaluri. BMC Microbiol 2019; 19:55. [PMID: 30849940 PMCID: PMC6408766 DOI: 10.1186/s12866-019-1429-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 02/27/2019] [Indexed: 01/23/2023] Open
Abstract
Background Edwardsiella ictaluri is a Gram-negative facultative intracellular anaerobe and the etiologic agent of enteric septicemia of channel catfish (ESC). To the catfish industry, ESC is a devastating disease due to production losses and treatment costs. Identification of virulence mechanisms of E. ictaluri is critical to developing novel therapeutic approaches for the disease. Here, we report construction of a transposon insertion library and identification of mutated genes in growth-delayed E. ictaluri colonies. We also provide safety and efficacy of transposon insertion mutants in catfish. Results An E. ictaluri transposon insertion library with 45,000 transposants and saturating 30.92% of the TA locations present in the E. ictaluri genome was constructed. Transposon end mapping of 250 growth-delayed E. ictaluri colonies and bioinformatic analysis of sequences revealed 56 unique E. ictaluri genes interrupted by the MAR2xT7 transposon, which are involved in metabolic and cellular processes and mostly localized in the cytoplasm or cytoplasmic membrane. Of the 56 genes, 30 were associated with bacterial virulence. Safety and vaccine efficacy testing of 19 mutants showed that mutants containing transposon insertions in hypothetical protein (Eis::004), and Fe-S cluster assembly protein (IscX, Eis::039), sulfurtransferase (TusA, Eis::158), and universal stress protein A (UspA, Eis::194) were safe and provided significant protection (p < 0.05) against wild-type E. ictaluri. Conclusions The results indicate that random transposon mutagenesis causing growth-delayed phenotype results in identification bacterial virulence genes, and attenuated strains with transposon interrupted virulence genes could be used as vaccine to activate fish immune system.
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Affiliation(s)
- Safak Kalindamar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Jingjun Lu
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA.
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Sodolescu A, Dian C, Terradot L, Bouzhir-Sima L, Lestini R, Myllykallio H, Skouloubris S, Liebl U. Structural and functional insight into serine hydroxymethyltransferase from Helicobacter pylori. PLoS One 2018; 13:e0208850. [PMID: 30550583 PMCID: PMC6294363 DOI: 10.1371/journal.pone.0208850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/23/2018] [Indexed: 11/19/2022] Open
Abstract
Serine hydroxymethyltransferase (SHMT), encoded by the glyA gene, is a ubiquitous pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the formation of glycine from serine. The thereby generated 5,10-methylene tetrahydrofolate (MTHF) is a major source of cellular one-carbon units and a key intermediate in thymidylate biosynthesis. While in virtually all eukaryotic and many bacterial systems thymidylate synthase ThyA, SHMT and dihydrofolate reductase (DHFR) are part of the thymidylate/folate cycle, the situation is different in organisms using flavin-dependent thymidylate synthase ThyX. Here the distinct catalytic reaction directly produces tetrahydrofolate (THF) and consequently in most ThyX-containing organisms, DHFR is absent. While the resulting influence on the folate metabolism of ThyX-containing bacteria is not fully understood, the presence of ThyX may provide growth benefits under conditions where the level of reduced folate derivatives is compromised. Interestingly, the third key enzyme implicated in generation of MTHF, serine hydroxymethyltransferase (SHMT), has a universal phylogenetic distribution, but remains understudied in ThyX-containg bacteria. To obtain functional insight into these ThyX-dependent thymidylate/folate cycles, we characterized the predicted SHMT from the ThyX-containing bacterium Helicobacter pylori. Serine hydroxymethyltransferase activity was confirmed by functional genetic complementation of a glyA-inactivated E. coli strain. A H. pylori ΔglyA strain was obtained, but exhibited markedly slowed growth and had lost the virulence factor CagA. Biochemical and spectroscopic evidence indicated formation of a characteristic enzyme-PLP-glycine-folate complex and revealed unexpectedly weak binding affinity of PLP. The three-dimensional structure of the H. pylori SHMT apoprotein was determined at 2.8Ǻ resolution, suggesting a structural basis for the low affinity of the enzyme for its cofactor. Stabilization of the proposed inactive configuration using small molecules has potential to provide a specific way for inhibiting HpSHMT.
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Affiliation(s)
- Andreea Sodolescu
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Cyril Dian
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris Saclay, Gif-sur-Yvette, France
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry, Institut de Biologie et Chimie des Protéines, CNRS, Université de Lyon, Lyon, France
| | - Latifa Bouzhir-Sima
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Roxane Lestini
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Hannu Myllykallio
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Stéphane Skouloubris
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
- Department of Biology, Université Paris-Sud, Université Paris Saclay, Orsay, France
| | - Ursula Liebl
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
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Ma W, Jia J, Huang X, Xie W, Zhang X, Tang J, Lin C, Zhao L, Fang P. Stable isotope labelling by amino acids in cell culture (SILAC) applied to quantitative proteomics of Edwardsiella tarda ATCC 15947 under prolonged cold stress. Microb Pathog 2018; 125:12-19. [PMID: 30201590 DOI: 10.1016/j.micpath.2018.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 09/01/2018] [Accepted: 09/05/2018] [Indexed: 01/15/2023]
Abstract
Edwardsiella tarda poses a threat to human health and has resulted in enormous economic losses in aquaculture. Low temperatures are usually applied to contain the growth of this microorganism. In this study, stable isotope labelling by amino acids in cell culture (SILAC) was used to conduct comparative proteomic quantitation of E. tarda ATCC 15947 under cold stress for two weeks. We identified 1391 proteins, of which 898 were quantifiable. Of these, 72 proteins were upregulated and 164 were downregulated in response to cold stress. Even though E. tarda ATCC 15947 is not a psychrophile, several key proteins related to DNA synthesis and transcription were significantly upregulated. Additionally, proteins related to haemolytic activities and gluconeogenesis were upregulated, even though E. tarda ATCC 15497 is considered non-virulent in aquaculture. This study therefore delineated the specific proteomic response of this E. tarda ATCC 15947 to prolonged cold stress.
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Affiliation(s)
- Weixing Ma
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China; Qingdao University of Science and Technology, No. 53, Zhengzhou Road, Qingdao, 266042, China
| | - Juntao Jia
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China.
| | - Xiaohua Huang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Wancui Xie
- Qingdao University of Science and Technology, No. 53, Zhengzhou Road, Qingdao, 266042, China
| | - Xiaoliang Zhang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Jing Tang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Chao Lin
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Liqing Zhao
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Peipei Fang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
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Ye JZ, Lin XM, Cheng ZX, Su YB, Li WX, Ali FM, Zheng J, Peng B. Identification and efficacy of glycine, serine and threonine metabolism in potentiating kanamycin-mediated killing of Edwardsiella piscicida. J Proteomics 2018; 183:34-44. [PMID: 29753025 DOI: 10.1016/j.jprot.2018.05.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/26/2018] [Accepted: 05/07/2018] [Indexed: 12/27/2022]
Abstract
We previously showed that glucose potentiated kanamycin to kill multidrug-resistant Edwardsiella piscicida through activation of the TCA cycle. However, whether other regulatory mechanism is involved requires further investigation. By quantitative proteomics technology, iTRAQ, we systematically mapped the altered proteins in the presence of glucose and identified 94 differentially expressed proteins. The analysis of the altered proteins by pathways, amino acid biosynthesis and metabolism were enriched. And the most significantly altered eight amino acids tyrosine, phenylalanine, valine, leucine, isoleucine, glycine, serine and threonine were investigated for their potentiation of kanamycin to kill EIB202, where glycine, serine and threonine showed the strongest efficacy than the others. The combinations of glycine and serine or glucose with glycine, serine or threonine had the best effects. Moreover, pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and succinate dehydrogenase activities were increased as well as the proton motive force (PMF) and intracellular kanamycin. Finally, inhibitors that disrupt PMF production abolished the potentiation. These results shed light on the mechanism of how glucose promoting the amino acids biosynthesis and metabolism to potentiate kanamycin to kill antibiotic-resistant bacteria. More importantly, our results suggested that adjusting amino acid biosynthesis and metabolism might be a strategy to become phenotypic resistance to antibiotics in bacteria. SIGNIFICANCE Tackling antibiotic resistance is an emerging issue in current years. Despite the efforts made toward developing new antibiotics, the progress is still lagged behind expectation. Novel strategies are required. The use of metabolite to revert antibiotic resistant is highly appreciated in recent years due to the less toxicity, more economic and high efficacy. As a continued study of our previous report on glucose potentiating kanamycin to kill antibiotic-resistant bacteria. The current study further expands the previous discovery on the mechanism of how glucose potentiate this effect. This result provides more basis on the action of glucose in reverting antibiotic resistance. And more importantly, we may derive more metabolites other than glucose to manage antibiotic resistance.
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Affiliation(s)
- Jin-Zhou Ye
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Xiang-Min Lin
- Fujian Provincial Key Laboratory, Agroecological Processing and Safety Monitoring, Key Laboratory of Crop Ecology and Molecular Physiology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China
| | - Zhi-Xue Cheng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Yu-Bin Su
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Wan-Xin Li
- Fujian Provincial Key Laboratory, Agroecological Processing and Safety Monitoring, Key Laboratory of Crop Ecology and Molecular Physiology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China
| | - Far-Man Ali
- Fujian Provincial Key Laboratory, Agroecological Processing and Safety Monitoring, Key Laboratory of Crop Ecology and Molecular Physiology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Bo Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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11
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Edrees A, Abdelhamed H, Nho SW, Park SB, Karsi A, Austin FW, Essa M, Pechan T, Lawrence ML. Construction and evaluation of type III secretion system mutants of the catfish pathogen Edwardsiella piscicida. JOURNAL OF FISH DISEASES 2018; 41:805-816. [PMID: 29424442 PMCID: PMC6080200 DOI: 10.1111/jfd.12784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/29/2017] [Accepted: 12/31/2017] [Indexed: 05/05/2023]
Abstract
Catfish is the largest aquaculture industry in the United States. Edwardsiellosis is considered one of the most significant problems affecting this industry. Edwardsiella piscicida is a newly described species within the genus Edwardsiella, and it was previously classified as Edwardsiella tarda. It causes gastrointestinal septicaemia, primarily in summer months, in farmed channel catfish in the south-eastern United States. In the current study, we adapted gene deletion methods used for Edwardsiella to E. piscicida strain C07-087, which was isolated from a disease outbreak in a catfish production pond. Four genes encoding structural proteins in the type III secretion system (T3SS) apparatus of E. piscicida were deleted by homologous recombination and allelic exchange to produce in-frame deletion mutants (EpΔssaV, EpΔesaM, EpΔyscR and EpΔescT). The mutants were phenotypically characterized, and virulence and vaccine efficacy were evaluated. Three of the mutants, EpΔssaV, EpΔyscR and EpΔesaM, were significantly attenuated compared to the parent strain (p < .05), but EpΔescT strain was not. Vaccination of catfish with the four mutant strains (EpΔssaV, EpΔesaM, EpΔyscR and EpΔescT) provided significant protection when subsequently challenged with wild-type strain. In conclusion, we report methods for gene deletion in E. piscicida and development of vaccine candidates derived from a virulent catfish isolate.
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Affiliation(s)
- A Edrees
- Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - H Abdelhamed
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - S W Nho
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - S B Park
- Department of Animal and Dairy Science, Mississippi State University, Mississippi State, MS, USA
| | - A Karsi
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - F W Austin
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - M Essa
- Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - T Pechan
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - M L Lawrence
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
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12
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Akgul A, Akgul A, Lawrence ML, Karsi A. Stress-related genes promote Edwardsiella ictaluri pathogenesis. PLoS One 2018; 13:e0194669. [PMID: 29554143 PMCID: PMC5858854 DOI: 10.1371/journal.pone.0194669] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/07/2018] [Indexed: 12/22/2022] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative anaerobic rod and the causative agent of enteric septicemia of channel catfish (ESC), which is one of the most prevalent diseases of catfish, causing significant economic losses in the catfish industry. E. ictaluri is resistant to complement system and macrophage killing, which results in rapid systemic septicemia. However, mechanisms of E. ictaluri stress responses under conditions of host environment are not studied well. Therefore, in this work, we report E. ictaluri stress responses during hydrogen peroxide, low pH, and catfish serum stresses as well as during catfish invasion. E. ictaluri stress responses were characterized by identifying expression of 13 universal stress protein (USP) genes (usp01-usp13) and seven USP-interacting protein genes (groEL, groES, dnaK, grpE, and clpB, grpE, relA). Data indicated that three usp genes (usp05, usp07, and usp13) were highly expressed in all stress conditions. Similarly, E. ictaluri heat shock proteins groEL, groES, dnaK, grpE, and clpB were highly expressed in oxidative stress. Also, E. ictaluri grpE and relA were highly expressed in catfish spleen and head kidney. These findings contribute to our understanding of stress response mechanisms in E. ictaluri stress response, and stress-related proteins that are essential for E. ictaluri could be potential targets for live attenuated vaccine development against ESC.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Ayfer Akgul
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Mark L. Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
- * E-mail:
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13
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Kordon AO, Abdelhamed H, Ahmed H, Park JY, Karsi A, Pinchuk LM. Phagocytic and Bactericidal Properties of Channel Catfish Peritoneal Macrophages Exposed to Edwardsiella ictaluri Live Attenuated Vaccine and Wild-Type Strains. Front Microbiol 2018; 8:2638. [PMID: 29375507 PMCID: PMC5767262 DOI: 10.3389/fmicb.2017.02638] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/18/2017] [Indexed: 12/13/2022] Open
Abstract
Edwardsiella ictaluri (E. ictaluri), a Gram-negative, intracellular, facultative bacterium, is the causative agent of enteric septicemia of catfish (ESC), which is one of the most significant diseases of farmed channel catfish. Macrophages have a critical role in major defense mechanisms against bacterial infections by migrating to the site of infection, engulfing and killing pathogens, and priming adaptive immune responses. Vaccination of catfish with E. ictaluri live attenuated vaccine (LAV) strains increased the efficiency of phagocytosis and bacterial killing in catfish peritoneal macrophages compared in vitro with macrophages from non-vaccinated fish. Recently, our group developed several protective LAV strains from E. ictaluri. However, their effects on the antigen uptake and bacterial killing in catfish macrophages have not been evaluated. In this study, we assessed the phagocytic and bactericidal activity of peritoneal macrophages in the uptake of E. ictaluri wild-type (WT) and two LAV strains. We found that phagocytosis of LAV strains was significantly higher compared to their WT counterpart in peritoneal macrophages. Moreover, the uptake of E. ictaluri opsonized with sera from vaccinated catfish was more efficient than when opsonized with sera from sham-vaccinated fish. Notably, catfish macrophages did not lose their phagocytic properties at 4°C, as described previously in mammalian and zebrafish models. Also, opsonization of E. ictaluri with inactivated sera from vaccinated and sham-vaccinated catfish decreased significantly phagocytic uptake of bacteria at 32°C, and virtually suppressed endocytosis at 4°C, suggesting the important role of complement-dependent mechanisms in catfish macrophage phagocytosis. In conclusion, our data on enhanced phagocytic capacity and effective killing ability in macrophages of vaccine strains suggested the LAVs’ advantage if processed and presented in the form of peptides to specific lymphocytes of an adaptive immune system and emphasize the importance of macrophage-mediated immunity against ESC. Furthermore, we showed the role of complement-dependent mechanisms in the phagocytic uptakes of E. ictaluri in catfish peritoneal macrophages at 4 and 32°C. Finally, LAV vaccine-induced bacterial phagocytosis and killing properties of peritoneal macrophages emphasized the importance of the innate immune responses in ESC.
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Affiliation(s)
- Adef O Kordon
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Hamada Ahmed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States.,Department of Nutrition and Veterinary Clinical Nutrition, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Joo Y Park
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Lesya M Pinchuk
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
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14
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Abdelhamed H, Ibrahim I, Baumgartner W, Lawrence ML, Karsi A. The virulence and immune protection of Edwardsiella ictaluri HemR mutants in catfish. FISH & SHELLFISH IMMUNOLOGY 2018; 72:153-160. [PMID: 29097322 DOI: 10.1016/j.fsi.2017.10.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/21/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular rod, causing enteric septicemia of catfish (ESC). Several heme uptake systems have been described in bacterial pathogens, most of which involve outer membrane proteins (OMPs). We have shown recently that heme/hemoglobin receptor family protein (HemR) is significantly up-regulated in E. ictaluri under iron-restricted conditions. In this work, our goal was to construct E. ictaluri HemR mutants and assess their virulence and immune protection potentials in catfish. To accomplish this, an in-frame deletion mutant (EiΔhemR) was constructed, and its virulence and immune protection were determined in catfish fingerlings and fry. The results indicated that the EiΔhemR was attenuated completely in catfish fingerlings, but it was virulent in 14 day-old catfish fry. To increase the attenuation of EiΔhemR in fry, we introduced frdA and sdhC gene deletions to the mutant, yielding two double (EiΔhemRΔfrdA and EiΔhemRΔsdhC) and one triple (EiΔhemRΔfrdAΔsdhC) mutants. Results indicated that two double HemR mutants did not exhibit increased attenuation, but the triple HemR mutant showed significantly less virulence and high protection in fry (p < 0.05). Histological examination of fry tissues vaccinated with the triple mutant displayed similar inflammation to that of wild-type infected fry, but much less necrosis and far fewer bacteria were observed. Immunohistochemistry (IHC) result indicated fewer numbers of bacteria around blood vessel and in the hematopoietic tissue in fry infected with triple mutant compared to control group infected with E. ictaluri wild-type. Our data indicated that EiΔhemR was safe and protective in catfish fingerlings, while EiΔhemRΔfrdAΔsdhC was much safer in catfish fry.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Iman Ibrahim
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA; Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Dakahlia 35516, Egypt
| | - Wes Baumgartner
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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15
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Cheng ZX, Gong QY, Wang Z, Chen ZG, Ye JZ, Li J, Wang J, Yang MJ, Ling XP, Peng B. Edwardsiella tarda Tunes Tricarboxylic Acid Cycle to Evade Complement-Mediated Killing. Front Immunol 2017; 8:1706. [PMID: 29270172 PMCID: PMC5725468 DOI: 10.3389/fimmu.2017.01706] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/20/2017] [Indexed: 01/12/2023] Open
Abstract
Evasion of complement-mediated killing is a common phenotype for many different types of pathogens, but the mechanism is still poorly understood. Most of the clinic isolates of Edwardsiella tarda, an important pathogen infecting both of human and fish, are commonly found serum-resistant. To explore the potential mechanisms, we applied gas chromatography-mass spectrometry (GC-MS)-based metabolomics approaches to profile the metabolomes of E. tarda EIB202 in the presence or absence of serum stress. We found that tricarboxylic acid (TCA) cycle was greatly enhanced in the presence of serum. The quantitative real-time PCR (qRT-PCR) and enzyme activity assays validated this result. Furthermore, exogenous succinate that promotes the TCA cycle increased serum resistance, while TCA cycle inhibitors (bromopyruvate and propanedioic acid) that inhibit TCA cycle, attenuated serum resistance. Moreover, the enhanced TCA cycle increased membrane potential, thus decreased the formation of membrane attack complex at cell surface, resulting serum resistance. These evidences suggested a previously unknown membrane potential-dependent mechanism of serum resistance. Therefore, our findings reveal that pathogen mounts a metabolic trick to cope with the serum complement-mediated killing.
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Affiliation(s)
- Zhi-Xue Cheng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qi-Yang Gong
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhe Wang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhuang-Gui Chen
- Pediatric Intensive Care Unit, Department of Pediatrics, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jin-Zhou Ye
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jun Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jie Wang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Man-Jun Yang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao-Peng Ling
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Bo Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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16
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Mou X, Spinard EJ, Hillman SL, Nelson DR. Isocitrate dehydrogenase mutation in Vibrio anguillarum results in virulence attenuation and immunoprotection in rainbow trout (Oncorhynchus mykiss). BMC Microbiol 2017; 17:217. [PMID: 29137620 PMCID: PMC5686843 DOI: 10.1186/s12866-017-1124-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/02/2017] [Indexed: 11/28/2022] Open
Abstract
Background Vibrio anguillarum is an extracellular bacterial pathogen that is a causative agent of vibriosis in finfish and crustaceans with mortality rates ranging from 30% to 100%. Mutations in central metabolism (glycolysis and the TCA cycle) of intracellular pathogens often result in attenuated virulence due to depletion of required metabolic intermediates; however, it was not known whether mutations in central metabolism would affect virulence in an extracellular pathogen such as V. anguillarum. Results Seven central metabolism mutants were created and characterized with regard to growth in minimal and complex media, expression of virulence genes, and virulence in juvenile rainbow trout (Oncorhynchus mykiss). Only the isocitrate dehydrogenase (icd) mutant was attenuated in virulence against rainbow trout challenged by either intraperitoneal injection or immersion. Further, the icd mutant was shown to be immunoprotective against wild type V. anguillarum infection. There was no significant decrease in the expression of the three hemolysin genes detected by qRT-PCR. Additionally, only the icd mutant exhibited a significantly decreased growth yield in complex media. Growth yield was directly related to the abundance of glutamate. A strain with a restored wild type icd gene was created and shown to restore growth to a wild type cell density in complex media and pathogenicity in rainbow trout. Conclusions The data strongly suggest that a decreased growth yield, resulting from the inability to synthesize α-ketoglutarate, caused the attenuation despite normal levels of expression of virulence genes. Therefore, the ability of an extracellular pathogen to cause disease is dependent upon the availability of host-supplied nutrients for growth. Additionally, a live vaccine strain could be created from an icd deletion strain. Electronic supplementary material The online version of this article (10.1186/s12866-017-1124-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiangyu Mou
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI, 02881, USA.,Present Address: Division of Infectious Diseases, Massachusetts General Hospital, 65 Landsdowne St, Cambridge, MA, 02139, USA
| | - Edward J Spinard
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI, 02881, USA
| | - Shelby L Hillman
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI, 02881, USA
| | - David R Nelson
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI, 02881, USA.
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17
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Nho SW, Abdelhamed H, Karsi A, Lawrence ML. Improving safety of a live attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish and evaluation of efficacy. Vet Microbiol 2017; 210:83-90. [DOI: 10.1016/j.vetmic.2017.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/26/2017] [Accepted: 09/13/2017] [Indexed: 12/19/2022]
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18
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Kumru S, Tekedar HC, Gulsoy N, Waldbieser GC, Lawrence ML, Karsi A. Comparative Analysis of the Flavobacterium columnare Genomovar I and II Genomes. Front Microbiol 2017; 8:1375. [PMID: 28790987 PMCID: PMC5524665 DOI: 10.3389/fmicb.2017.01375] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 07/06/2017] [Indexed: 11/16/2022] Open
Abstract
Columnaris disease caused by Gram-negative rod Flavobacterium columnare is one of the most common diseases of catfish. F. columnare is also a common problem in other cultured fish species worldwide. F. columnare has three major genomovars; we have sequenced a representative strain from genomovar I (ATCC 49512, which is avirulent in catfish) and genomovar II (94-081, which is highly pathogenic in catfish). Here, we present a comparative analysis of the two genomes. Interestingly, F. columnare ATCC 49512 and 94-081 meet criteria to be considered different species based on the Average Nucleotide Identity (90.71% similar) and DNA–DNA Hybridization (42.6% similar). Genome alignment indicated the two genomes have a large number of rearrangements. However, function-based comparative genomics analysis indicated that the two strains have similar functional capabilities with 2,263 conserved orthologous clusters; strain ATCC 49512 has 290 unique orthologous clusters while strain 94-081 has 391. Both strains carry type I secretion system, type VI secretion system, and type IX secretion system. The two genomes also have similar CRISPR capacities. The F. columnare strain ATCC 49512 genome contains a higher number of insertion sequence families and phage regions, while the F. columnare strain 94-081 genome has more genomic islands and more regulatory gene capacity. Transposon mutagenesis using Tn4351 in pathogenic strain 94-081 yielded six mutants, and experimental infections of fish showed hemolysin and glycine cleavage protein mutants had 15 and 10% mortalities, respectively, while the wild-type strain caused 100% mortalities. Our comparative and mutational analysis yielded important information on classification of genomovars I and II F. columnare as well as potential virulence genes in F. columnare strain 94-081.
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Affiliation(s)
- Salih Kumru
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Nagihan Gulsoy
- Department of Biology, Faculty of Art and Sciences, Marmara UniversityIstanbul, Turkey
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, United States Agricultural Research Service, StonevilleMS, United States
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
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19
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Senior NJ, Sasidharan K, Saint RJ, Scott AE, Sarkar-Tyson M, Ireland PM, Bullifent HL, Rong Yang Z, Moore K, Oyston PCF, Atkins TP, Atkins HS, Soyer OS, Titball RW. An integrated computational-experimental approach reveals Yersinia pestis genes essential across a narrow or a broad range of environmental conditions. BMC Microbiol 2017; 17:163. [PMID: 28732479 PMCID: PMC5521123 DOI: 10.1186/s12866-017-1073-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/17/2017] [Indexed: 01/07/2023] Open
Abstract
Background The World Health Organization has categorized plague as a re-emerging disease and the potential for Yersinia pestis to also be used as a bioweapon makes the identification of new drug targets against this pathogen a priority. Environmental temperature is a key signal which regulates virulence of the bacterium. The bacterium normally grows outside the human host at 28 °C. Therefore, understanding the mechanisms that the bacterium used to adapt to a mammalian host at 37 °C is central to the development of vaccines or drugs for the prevention or treatment of human disease. Results Using a library of over 1 million Y. pestis CO92 random mutants and transposon-directed insertion site sequencing, we identified 530 essential genes when the bacteria were cultured at 28 °C. When the library of mutants was subsequently cultured at 37 °C we identified 19 genes that were essential at 37 °C but not at 28 °C, including genes which encode proteins that play a role in enabling functioning of the type III secretion and in DNA replication and maintenance. Using genome-scale metabolic network reconstruction we showed that growth conditions profoundly influence the physiology of the bacterium, and by combining computational and experimental approaches we were able to identify 54 genes that are essential under a broad range of conditions. Conclusions Using an integrated computational-experimental approach we identify genes which are required for growth at 37 °C and under a broad range of environments may be the best targets for the development of new interventions to prevent or treat plague in humans. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-1073-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nicola J Senior
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
| | - Kalesh Sasidharan
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Richard J Saint
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Andrew E Scott
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Mitali Sarkar-Tyson
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK.,Marshall Centre for Infectious Disease Research and Training, School of Pathology and Laboratory Medicine, University of Western Australia, Perth, WA, 6009, Australia
| | - Philip M Ireland
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Helen L Bullifent
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Z Rong Yang
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
| | - Karen Moore
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
| | - Petra C F Oyston
- Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Timothy P Atkins
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK.,Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Helen S Atkins
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK.,Defence Science Technology Laboratory, Porton Down, Salisbury, SP4 OJQ, UK
| | - Orkun S Soyer
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Richard W Titball
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK.
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20
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Abdelhamed H, Lu J, Lawrence ML, Karsi A. Ferric hydroxamate uptake system contributes to Edwardsiella ictaluri virulence. Microb Pathog 2016; 100:195-200. [PMID: 27666508 DOI: 10.1016/j.micpath.2016.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/13/2016] [Accepted: 09/21/2016] [Indexed: 11/16/2022]
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen causing enteric septicemia in fish, particularly in channel catfish. Ferric iron is an essential micronutrient for bacterial survival, and some bacterial pathogens use secreted hydroxamate-type siderophores to chelate iron in host tissues. Siderophore-iron complexes are taken up by these bacteria via the ferric hydroxamate uptake (Fhu) system. In E. ictaluri, the Fhu system consists of fhuC, fhuD, fhuB, and fhuA genes. However, the importance of the Fhu system in E. ictaluri virulence has not been investigated completely. Here, we present construction of E. ictaluri fhuD and fhuB mutants (EiΔfhuD and EiΔfhuB) by in-frame gene deletion and evaluation of the mutants' virulence and immunogenicity in channel catfish fingerlings and fry. Immersion challenges showed that EiΔfhuD was not significantly attenuated (p < 0.05) in catfish fingerlings, whereas EiΔfhuB was significantly attenuated (p < 0.01). Catfish fingerlings immunized with EiΔfhuD and EiΔfhuB showed 100% and 97.62% survival, respectively. Fry immersion challenges indicated EiΔfhuB was also significantly attenuated (p < 0.05) in two-week old fry compared to the wild-type (48.96% vs. 82.14% mortalities). The survival rate in the fry vaccinated with EiΔfhuB was significantly higher (p < 0.05) than that of non-vaccinated fry (96.77% vs. 21.42% survival). Our data indicates that the fhuB gene, but not the fhuD gene, contributes to E. ictaluri virulence.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Jingjun Lu
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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21
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Huang L, Huang L, Yan Q, Qin Y, Ma Y, Lin M, Xu X, Zheng J. The TCA Pathway is an Important Player in the Regulatory Network Governing Vibrio alginolyticus Adhesion Under Adversity. Front Microbiol 2016; 7:40. [PMID: 26870007 PMCID: PMC4735382 DOI: 10.3389/fmicb.2016.00040] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/11/2016] [Indexed: 12/24/2022] Open
Abstract
Adhesion is a critical step in the initial stage of Vibrio alginolyticus infection; therefore, it is important to understand the underlying mechanisms governing the adhesion of V. alginolyticus and determine if environmental factors have any effect. A greater understanding of this process may assist in developing preventive measures for reducing infection. In our previous research, we presented the first RNA-seq data from V. alginolyticus cultured under stress conditions that resulted in reduced adhesion. Based on the RNA-seq data, we found that the Tricarboxylic acid cycle (TCA pathway) might be closely related to adhesion. Environmental interactions with the TCA pathway might alter adhesion. To validate this, bioinformatics analysis, quantitative Real-Time PCR (qPCR), RNAi, and in vitro adhesion assays were performed, while V. alginolyticus was treated with various stresses including temperature, pH, salinity, and starvation. The expression of genes involved in the TCA pathway was confirmed by qPCR, which reinforced the reliability of the sequencing data. Silencing of these genes was capable of reducing the adhesion ability of V. alginolyticus. Adhesion of V. alginolyticus is influenced substantially by environmental factors and the TCA pathway is sensitive to some environmental stresses, especially changes in pH and starvation. Our results indicated that (1) the TCA pathway plays a key role in V. alginolyticus adhesion: (2) the TCA pathway is sensitive to environmental stresses.
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Affiliation(s)
- Lixing Huang
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Li Huang
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Qingpi Yan
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Yingxue Qin
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Ying Ma
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Mao Lin
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Xiaojin Xu
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
| | - Jiang Zheng
- Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University Xiamen, China
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22
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Altinok I, Capkin E, Karsi A. Succinate dehydrogenase mutant of Listonella anguillarum protects rainbow trout against vibriosis. Vaccine 2015; 33:5572-5577. [PMID: 26382599 DOI: 10.1016/j.vaccine.2015.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
Abstract
Listonella anguillarum is a Gram-negative facultative anaerobic rod causing hemorrhagic septicemia in marine and rarely in freshwater fish. Succinate dehydrogenase (SDH) plays an important role in the tricarboxylic acid (TCA) cycle by oxidizing succinate to fumarate while reducing ubiquinone to ubiquinol. Recent studies indicate that central metabolic pathways, including the TCA cycle, contribute to bacterial virulence. However, the role of SDH in L. anguillarum virulence has not been studied. Here, we report in-frame deletion of the succinate dehydrogenase iron-sulfur protein (SDHB) and its role in L. anguillarum virulence in rainbow trout. To accomplish this goal, upstream and downstream regions of the L. anguillarum sdhB gene were amplified in-frame and cloned into a suicide plasmid. The chromosomal sdhB gene of L. anguillarum was deleted by homologous recombination. Virulence and immunogenicity of the L. anguillarum ΔsdhB mutant (LaΔsdhB) were determined in rainbow trout. Results show that LaΔsdhB was highly attenuated in rainbow trout, and fish immunized with LaΔsdhB displayed high relative survival rate after exposure to wild type L. anguillarum. These findings indicate SDH is important in L. anguillarum virulence in rainbow trout, and LaΔsdhB could be used as an immersion, oral, or injection vaccine to protect rainbow trout against vibriosis.
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Affiliation(s)
- Ilhan Altinok
- Department of Fisheries Technology Engineering, Faculty of Marine Science, Karadeniz Technical University, Trabzon 61530, Turkey.
| | - Erol Capkin
- Department of Fisheries Technology Engineering, Faculty of Marine Science, Karadeniz Technical University, Trabzon 61530, Turkey
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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23
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Conway T, Cohen PS. Commensal and Pathogenic Escherichia coli Metabolism in the Gut. Microbiol Spectr 2015; 3:10.1128/microbiolspec.MBP-0006-2014. [PMID: 26185077 PMCID: PMC4510460 DOI: 10.1128/microbiolspec.mbp-0006-2014] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Indexed: 12/22/2022] Open
Abstract
E. coli is a ubiquitous member of the intestinal microbiome. This organism resides in a biofilm comprised of a complex microbial community within the mucus layer where it must compete for the limiting nutrients that it needs to grow fast enough to stably colonize. In this article we discuss the nutritional basis of intestinal colonization. Beginning with basic ecological principles we describe what is known about the metabolism that makes E. coli such a remarkably successful member of the intestinal microbiota. To obtain the simple sugars and amino acids that it requires, E. coli depends on degradation of complex glycoproteins by strict anaerobes. Despite having essentially the same core genome and hence the same metabolism when grown in the laboratory, different E. coli strains display considerable catabolic diversity when colonized in mice. To explain why some E. coli mutants do not grow as well on mucus in vitro as their wild type parents yet are better colonizers, we postulate that each one resides in a distinct "Restaurant" where it is served different nutrients because it interacts physically and metabolically with different species of anaerobes. Since enteric pathogens that fail to compete successfully for nutrients cannot colonize, a basic understanding of the nutritional basis of intestinal colonization will inform efforts to develop prebiotics and probiotics to combat infection.
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Affiliation(s)
- Tyrrell Conway
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, Phone: 405-820-7329,
| | - Paul S. Cohen
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, Phone: 401-874-5920,
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24
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Tissue persistence and vaccine efficacy of tricarboxylic acid cycle and one-carbon metabolism mutant strains of Edwardsiella ictaluri. Vaccine 2014; 32:3971-6. [PMID: 24837777 DOI: 10.1016/j.vaccine.2014.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/25/2014] [Accepted: 05/01/2014] [Indexed: 11/22/2022]
Abstract
Edwardsiella ictaluri causes enteric septicemia in fish. Recently, we reported construction of E. ictaluri mutants with single and double gene deletions in tricarboxylic acid cycle (TCA) and one-carbon (C-1) metabolism. Here, we report the tissue persistence, virulence, and vaccine efficacy of TCA cycle (EiΔsdhC, EiΔfrdA, and EiΔmdh), C-1 metabolism (EiΔgcvP and EiΔglyA), and combination mutants (EiΔfrdAΔsdhC, EiΔgcvPΔsdhC, EiΔmdhΔsdhC, and EiΔgcvPΔglyA) in channel catfish. The tissue persistence study showed that EiΔsdhC, EiΔfrdA, EiΔfrdAΔsdhC, and EiΔgcvPΔsdhC were able to invade catfish and persist until 11 days post-infection. Vaccination of catfish fingerlings with all nine mutants provided significant (P<0.05) protection against subsequent challenge with the virulent parental strain. Vaccinated catfish fingerlings had 100% survival when subsequently challenged by immersion with wild-type E. ictaluri except for EiΔgcvPΔglyA and EiΔgcvP. Mutant EiΔgcvPΔsdhC was found to be very good at protecting catfish fry, as evidenced by 10-fold higher survival compared to non-vaccinated fish.
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Brown MJ, Russo BC, O'Dee DM, Schmitt DM, Nau GJ. The contribution of the glycine cleavage system to the pathogenesis of Francisella tularensis. Microbes Infect 2013; 16:300-9. [PMID: 24374051 DOI: 10.1016/j.micinf.2013.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 12/04/2013] [Accepted: 12/17/2013] [Indexed: 02/07/2023]
Abstract
Biosynthesis and acquisition of nutrients during infection are integral to pathogenesis. Members of a metabolic pathway, the glycine cleavage system, have been identified in virulence screens of the intracellular bacterium Francisella tularensis but their role in pathogenesis remains unknown. This system generates 5,10-methylenetetrahydrofolate, a precursor of amino acid and DNA synthesis, from glycine degradation. To characterize this pathway, deletion of the gcvT homolog, an essential member of this system, was performed in attenuated and virulent F. tularensis strains. Deletion mutants were auxotrophic for serine but behaved similar to wild-type strains with respect to host cell invasion, intracellular replication, and stimulation of TNF-α. Unexpectedly, the glycine cleavage system was required for the pathogenesis of virulent F. tularensis in a murine model. Deletion of the gcvT homolog delayed mortality and lowered bacterial burden, particularly in the liver and bloodstream. To reconcile differences between the cell culture model and animal model, minimal tissue culture media was employed to mimic the nutritionally limiting environment of the host. This reevaluation demonstrated that the glycine cleavage system contributes to the intracellular replication of virulent F. tularensis in serine limiting environments. Thus, the glycine cleavage system is the serine biosynthetic pathway of F. tularensis and contributes to pathogenesis in vivo.
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Affiliation(s)
- Matthew J Brown
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Brian C Russo
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Dawn M O'Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Deanna M Schmitt
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Gerard J Nau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Medicine - Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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26
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Dahal N, Abdelhamed H, Lu J, Karsi A, Lawrence ML. Effect of multiple mutations in tricarboxylic acid cycle and one-carbon metabolism pathways on Edwardsiella ictaluri pathogenesis. Vet Microbiol 2013; 169:107-12. [PMID: 24418045 DOI: 10.1016/j.vetmic.2013.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/18/2013] [Accepted: 12/10/2013] [Indexed: 09/30/2022]
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen causing enteric septicemia of catfish (ESC). We have shown recently that tricarboxylic acid cycle (TCA) and one-carbon (C1) metabolism are involved in E. ictaluri pathogenesis. However, the effect of multiple mutations in these pathways is unknown. Here, we report four novel E. ictaluri mutants carrying double gene mutations in TCA cycle (EiΔmdhΔsdhC, EiΔfrdAΔsdhC), C1 metabolism (EiΔglyAΔgcvP), and both TCA and C1 metabolism pathways (EiΔgcvPΔsdhC). In-frame gene deletions were constructed by allelic exchange and mutants' virulence and vaccine efficacy were evaluated using in vivo bioluminescence imaging (BLI) as well as end point mortality counts in catfish fingerlings. Results indicated that all the double gene mutants were attenuated compared to wild-type (wt) E. ictaluri. There was a 1.39-fold average reduction in bioluminescence, and hence bacterial numbers, from all the mutants except for EiΔfrdAΔsdhC at 144 h post-infection. Vaccination with mutants was very effective in protecting channel catfish against subsequent infection with virulent E. ictaluri 93-146 strain. In particular, immersion vaccination resulted in complete protection. Our results provide further evidence on the importance of TCA and C1 metabolism pathways in bacterial pathogenesis.
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Affiliation(s)
- N Dahal
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - H Abdelhamed
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Benha University, Moshtohor-Toukh, Egypt
| | - J Lu
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - A Karsi
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
| | - M L Lawrence
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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