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Bista PK, Pillai D, Narayanan SK. Characterization of Three New Outer Membrane Adhesion Proteins in Fusobacterium necrophorum. Microorganisms 2023; 11:2968. [PMID: 38138112 PMCID: PMC10745669 DOI: 10.3390/microorganisms11122968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
Fusobacterium necrophorum, an anaerobic Gram-negative pathogen, causes necrotic cattle infections, impacting livestock health and the US feedlot industry. Antibiotic administration is the mainstay for treating F. necrophorum infections, although resistance hampers their effectiveness. Vaccination, especially targeting outer membrane proteins (OMPs) due to their antigenic properties and host specificity, offers an alternative to antibiotics. This study identified high-binding-affinity adhesion proteins from F. necrophorum using binding and pull-down assays with bovine adrenal gland endothelial cells (EJG). Four OMP candidates (17.5 kDa/OmpH, 22.7 kDa/OmpA, 66.3 kDa/cell surface protein (CSP), and a previously characterized 43 kDa OMP) were expressed as recombinant proteins and purified. Rabbit polyclonal antibodies to recombinant OMPs were generated, and their ability to inhibit bacterial binding in vitro was assessed. The results show that treatment with individual polyclonal antibodies against 43 kDa significantly inhibited bacterial adhesion, while other antibodies were less potent. However, combinations of two or more antibodies showed a more prominent inhibitory effect on host-cell adhesion. Thus, our findings suggest that the identified OMPs are involved in fusobacterial attachment to host cells and may have the potential to be leveraged in combination for vaccine development. Future in vivo studies are needed to validate their roles and test the feasibility of an OMP-based subunit vaccine against fusobacterial infections.
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Affiliation(s)
- Prabha K. Bista
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
| | - Deepti Pillai
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
- Indiana Animal Disease and Diagnostic Laboratory, Purdue University, West Lafayette, IN 47907, USA
| | - Sanjeev K. Narayanan
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
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Bista PK, Pillai D, Narayanan SK. Outer-Membrane Vesicles of Fusobacterium necrophorum: A Proteomic, Lipidomic, and Functional Characterization. Microorganisms 2023; 11:2082. [PMID: 37630642 PMCID: PMC10458137 DOI: 10.3390/microorganisms11082082] [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: 05/18/2023] [Revised: 08/10/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Outer-membrane vesicles (OMVs) are extruded nanostructures shed by Gram-negative bacteria, containing periplasmic contents, and often including virulence factors with immunogenic properties. To assess their potential for use in vaccine development, we purified OMVs from the Fusobacterium necrophorum subspecies necrophorum, an opportunistic necrotic infection-causing pathogen, and characterized these structures using proteomics, lipid-profiling analyses, and cytotoxicity assays. A proteomic analysis of density-gradient-purified F. necrophorum OMVs identified 342 proteins, a large proportion of which were outer-membrane proteins (OMPs), followed by cytoplasmic proteins, based on a subcellular-localization-prediction analysis. The OMPs and toxins were among the proteins with the highest intensity identified, including the 43-kDa-OMP-, OmpA-, and OmpH-family proteins, the cell-surface protein, the FadA adhesin protein, the leukotoxin-LktA-family filamentous adhesin, the N-terminal domain of hemagglutinin, and the OMP transport protein and assembly factor. A Western blot analysis confirmed the presence of several OMPs and toxins in the F. necrophorum OMVs. The lipid-profiling analysis revealed phospholipids, sphingolipids, and acetylcarnitine as the main lipid contents of OMVs. The lactate-dehydrogenase-cytotoxicity assays showed that the OMVs had a high degree of cytotoxicity against a bovine B-lymphocyte cell line (BL-3 cells). Thus, our data suggest the need for further studies to evaluate the ability of OMVs to induce immune responses and assess their vaccine potential in vivo.
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Affiliation(s)
- Prabha K. Bista
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
| | - Deepti Pillai
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
- Indiana Animal Disease and Diagnostic Laboratory, Purdue University, West Lafayette, IN 47907, USA
| | - Sanjeev K. Narayanan
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; (P.K.B.); (D.P.)
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He X, Liu J, Jiang K, Lian S, Shi Y, Fu S, Zhao P, Xiao J, Sun D, Guo D. The outer membrane protein of Fusobacterium necrophorum, 43K OMP, stimulates inflammatory cytokine production through nuclear factor kappa B activation. Anaerobe 2023; 82:102768. [PMID: 37541484 DOI: 10.1016/j.anaerobe.2023.102768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/06/2023]
Abstract
OBJECTIVE Fusobacterium necrophorum causes bovine hepatic abscess, foot rot, mastitis, and endometritis. The 43 kDa outer membrane protein (43 K OMP) of F. necrophorum is a porin protein that plays an important role in infections by this bacterium, but the biological function and the pathogenesis of this protein are largely unknown. METHODS In this study, we investigated the role of the 43 K OMP in bacterial infection of bovine mammary epithelial cells (MAC-T cells) by Tandem Mass Tag proteomic analysis. The RAW264.7 cells were incubated with recombinant 43 K OMP (12.5 μg/mL) for 2 h, 4 h, 6 h, and 12 h, and then the inflammatory related protein and inflammatory cytokine production were measured by Western blot analysis and ELISA, the mRNA expression levels of inflammatory cytokine were measured by Real-Time PCR. RESULTS Proteomic analysis results demonstrated there were 224 differentially expressed proteins in the MAC-T cells stimulated with the 43 K OMP compared with control, and 118 proteins were upregulated and 106 proteins were downregulated. These differentially expressed proteins were mainly involved in NF-kappa B signaling, bacterial invasion of epithelial cells, cell adhesion, complement and coagulation cascades. The top six differentially expressed proteins were; MMP9, PLAU, STOM, PSMD13, PLAUR, and ITGAV, which were involved in a protein-protein interaction network. Furthermore, TLR/MyD88/NF-κB pathway related proteins and inflammatory cytokines (IL-6, TNF-α, and IL-1β) were assessed by Western blot analysis and ELISA. Results showed the 43 K OMP to enhance the expression of TLR4 protein at 2 h (P < 0.01) and the MyD88 protein at 4 h (P < 0.05) post-stimulation, and to decrease IκBα expression at 4 h, 6 h and 12 h (P < 0.05) post-infection, as well as induce phosphorylation at Ser536 (P < 0.01). Levels of IL-6, IL-1β, and TNF-α in the supernatants of mouse macrophages were increased (P < 0.05), as were mRNA expression levels of IL-6, IL-1β, and TNF-α (P < 0.05), while IL-4 mRNA expression was decreased (P < 0.05). CONCLUSIONS Taken together, these results suggested the important role for 43 K OMP in F. necrophorum infection, promoting the production of pro-inflammatory cytokines (IL-6 and TNF-α) by activation of the TLR/MyD88/NF-κB pathway. These findings provided a theoretical basis for a better understanding of the pathogenesis of F. necrophorum infection.
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Affiliation(s)
- Xianjing He
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China.
| | - Jiao Liu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Kai Jiang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Shuai Lian
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Yu Shi
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Shan Fu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Pengyu Zhao
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Jiawei Xiao
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
| | - Dongbo Sun
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China.
| | - Donghua Guo
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China; Ministry of Agriculture and Rural Affairs Key Laboratory of Prevention and Control of Bovine Diseases, No. 5 Xinyang Road, Sartu District, Daqing 163319, Heilongjiang Province, China
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Schwarz C, Mathieu J, Gomez JL, Miller MR, Tikhonova M, Nagaraja T, Alvarez PJJ. Unexpected finding of Fusobacterium varium as the dominant Fusobacterium species in cattle rumen: potential implications for liver abscess etiology and interventions. J Anim Sci 2023; 101:skad130. [PMID: 37104065 PMCID: PMC10195197 DOI: 10.1093/jas/skad130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/25/2023] [Indexed: 04/28/2023] Open
Abstract
Fusobacterium varium has been generally overlooked in cattle rumen microbiome studies relative to the presumably more abundant liver abscess-causing Fusobacterium necrophorum. However, F. varium was found to be more abundant in the rumen fluid of cattle and under culture conditions tailored to enrich F. necrophorum. Using near-full length 16S ribosomal ribonucleic acid sequencing, we demonstrate that F. varium grows under restrictive conditions commonly used to enumerate F. necrophorum, suggesting that previous F. necrophorum abundance assessment may have been inaccurate and that F. varium may be an underestimated member of the ruminal bacterial community. Fusobacterium varium were not as susceptible as F. necrophorum to in-feed antibiotics conventionally used in feedlots. Exposure to tylosin, the current gold standard for liver abscess reduction strategies in cattle, consistently hindered growth of the F. necrophorum strains tested by over 67% (P < 0.05) relative to the unexposed control. In contrast, F. varium strains were totally or highly resistant (0%-13% reduction in maximum yield, P < 0.05). Monensin, an ionophore antibiotic, had greater inhibitory activity against F. necrophorum than F. varium. Finally, preliminary genomic analysis of two F. varium isolates from the rumen revealed the presence of virulence genes related to those of pathogenic human F. varium isolates associated with active invasion of mammalian cells. The data presented here encourage further investigation into the ecological role of F. varium within the bovine rumen and potential role in liver abscess development, and proactive interventions.
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Affiliation(s)
- Cory Schwarz
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
- Sentinel Environmental Group, LLC, Houston, TX 77082, USA
| | - Jacques Mathieu
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
- Sentinel Environmental Group, LLC, Houston, TX 77082, USA
| | | | - Megan R Miller
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
| | | | - Tiruvoor.G Nagaraja
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
- Sentinel Environmental Group, LLC, Houston, TX 77082, USA
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Holm K, Collin M, Hagelskjær-Kristensen L, Jensen A, Rasmussen M. Three variants of the leukotoxin gene in human isolates of Fusobacterium necrophorum subspecies funduliforme. Anaerobe 2017; 45:129-132. [DOI: 10.1016/j.anaerobe.2017.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/15/2017] [Accepted: 03/17/2017] [Indexed: 02/04/2023]
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Amachawadi RG, Nagaraja TG. Liver abscesses in cattle: A review of incidence in Holsteins and of bacteriology and vaccine approaches to control in feedlot cattle12. J Anim Sci 2016; 94:1620-32. [DOI: 10.2527/jas.2015-0261] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Control of liver abscesses in feedlot cattle: A review11Contribution no. 10-205-J from the Kansas Agric. Exp. Stn., Manhattan 66506. ACTA ACUST UNITED AC 2015. [DOI: 10.15232/pas.2014-01364] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Kumar A, Gart E, Nagaraja T, Narayanan S. Adhesion of Fusobacterium necrophorum to bovine endothelial cells is mediated by outer membrane proteins. Vet Microbiol 2013; 162:813-818. [DOI: 10.1016/j.vetmic.2012.10.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
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10
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Ovine footrot: new approaches to an old disease. Vet Microbiol 2010; 148:1-7. [PMID: 20926208 DOI: 10.1016/j.vetmic.2010.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 09/02/2010] [Accepted: 09/02/2010] [Indexed: 11/20/2022]
Abstract
Footrot is a bacterial disease that has substantial economic and welfare impacts in sheep and can be difficult to manage. Research is focussed on reducing the impact that footrot has on farmers and their flocks and better understanding the aetiology of the disease. Key areas of current research include, developing better vaccines, deploying tailored vaccines in a specific and targeted fashion on individual farms, analysing and developing better farm management practices to suit specific sheep farming environments, elucidating the virulence genes and bacterial population dynamics that drive footrot and using genetic testing in combination with selective breeding to produce stock that are more resilient to disease.
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11
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An indirect ELISA for serodiagnosis of cattle footrot caused by Fusobacterium necrophorum. Anaerobe 2010; 16:317-20. [DOI: 10.1016/j.anaerobe.2010.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 02/09/2010] [Accepted: 03/12/2010] [Indexed: 11/18/2022]
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12
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Ludlam HA, Milner NJ, Brazier JS, Davies IH, Perry K, Marriott RK, Donachie L, Curran MD. lktA-encoded leukotoxin is not a universal virulence factor in invasive Fusobacterium necrophorum infections in animals and man. J Med Microbiol 2009; 58:529-530. [PMID: 19273652 DOI: 10.1099/jmm.0.005231-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Hugo A Ludlam
- Health Protection Agency (East of England), Addenbrookes Hospital, Cambridge, UK
| | - Nicola J Milner
- Health Protection Agency (East of England), Addenbrookes Hospital, Cambridge, UK
| | - Jon S Brazier
- Anaerobe Reference Laboratory, University Hospital of Wales, Cardiff, UK
| | | | - Kevin Perry
- Veterinary Laboratories Agency, Winchester, UK
| | - Rosemary K Marriott
- Health Protection Agency (East of England), Addenbrookes Hospital, Cambridge, UK
| | - Linda Donachie
- Health Protection Agency (East of England), Addenbrookes Hospital, Cambridge, UK
| | - Martin D Curran
- Health Protection Agency (East of England), Addenbrookes Hospital, Cambridge, UK
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13
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Identification of three immunodominant regions on leukotoxin protein of Fusobacterium necrophorum. Vet Res Commun 2009; 33:749-55. [PMID: 19449113 DOI: 10.1007/s11259-009-9223-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 04/24/2009] [Indexed: 10/20/2022]
Abstract
To analyze immunodominant regions of leukotoxin protein of Fusobacterium necrophorum strain H05, a series of truncated forms of leukotoxin gene were expressed in Escherichia coli using the vector pGEX-6p-1 or pPROEX HTa. The results of SDS-PAGE showed the truncated forms PL1, PL2, PL4, and PL5 were expressed in Escherichia coli using the vector pGEX-6p-1, and the truncated forms PL3 was expressed in Escherichia coli using the vector pPROEX HTa. These recombinant proteins were able to react with antisera against Fusobacterium necrophorum strain A25. In five recombinant proteins, the recombinant proteins PL1, PL3 and PL4 as vaccine were able to elicit formation of the better protective effects on mice against infection of Fusobacterium necrophorum strain A25.
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14
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Tadepalli S, Narayanan S, Stewart G, Chengappa M, Nagaraja T. Fusobacterium necrophorum: A ruminal bacterium that invades liver to cause abscesses in cattle. Anaerobe 2009; 15:36-43. [DOI: 10.1016/j.anaerobe.2008.05.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 04/30/2008] [Accepted: 05/17/2008] [Indexed: 11/28/2022]
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15
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Advances in microbial ecosystem concepts and their consequences for ruminant agriculture. Animal 2008; 2:653-60. [PMID: 22443590 DOI: 10.1017/s1751731108002164] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Abstract
Liver abscesses in feedlot cattle result from aggressive grain-feeding programs and are influenced by a number of dietary and management factors. They have a major economic impact on the feedlot industry because of liver condemnation and reduced animal performance and carcass yield. Ruminal lesions resulting from acidosis usually are accepted as the predisposing factors. Generally, control of liver abscesses in feedlot cattle has depended on the use of tylosin, which reduces abscess incidence by 40% to 70%. However, new methods and products for liver abscess control are needed. Corn milling by-products that are less fermentable may aide in the quest for cattle production techniques that lead to lower usage of antimicrobials. A vaccine is also commercially available.
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Affiliation(s)
- T G Nagaraja
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606, USA.
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17
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Narayanan SK, Chengappa MM, Stewart GC, Nagaraja TG. Immunogenicity and protective effects of truncated recombinant leukotoxin proteins of Fusobacterium necrophorum in mice. Vet Microbiol 2003; 93:335-47. [PMID: 12713895 DOI: 10.1016/s0378-1135(03)00045-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Fusobacterium necrophorum, a gram-negative, anaerobic and rod-shaped bacterium, is generally an opportunistic pathogen and causes a wide variety of necrotic infections in animals and humans. Leukotoxin, a secreted protein, is a major virulence factor. The gene encoding the leukotoxin (lktA) in F. necrophorum has been cloned, sequenced and expressed in Escherichia coli. Because of low expression levels, problems associated with purifying full-length recombinant protein, and of the physical instability of the protein, five overlapping leukotoxin gene truncations were constructed. The recombinant polypeptides (BSBSE, SX, GAS, SH, and FINAL) were expressed in E. coli and purified by nickel-affinity chromatography. The objectives were to investigate the effectiveness of the purified truncated polypeptides to induce protective immunity in mice challenged with F. necrophorum. The polypeptides, individually or in combination, and inactivated native leukotoxin or culture supernatant of F. necrophorum were homogenized with an adjuvant and injected into mice on days 0 and 21. Blood samples were collected to measure serum anti-leukotoxin antibody titers on days 0, 21 and 42 and on day 42, mice were experimentally challenged with F. necrophorum. All polypeptides were immunogenic, with GAS polypeptide eliciting the least antibody response. Two polypeptides (BSBSE and SH) induced significant protection in mice against F. necrophorum infection. Protection was better than the full-length native leukotoxin or inactivated supernatant.The study demonstrated that the leukotoxin of F. necrophorum carries epitopes that induce protective immunity against experimental fusobacterial infection, thus providing further evidence to the importance of leukotoxin as a major virulence factor.
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Affiliation(s)
- Sanjeev Kumar Narayanan
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 305 Coles Hall, Manhattan, KS 66506-5606, USA
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18
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Narayanan S, Stewart GC, Chengappa MM, Willard L, Shuman W, Wilkerson M, Nagaraja TG. Fusobacterium necrophorum leukotoxin induces activation and apoptosis of bovine leukocytes. Infect Immun 2002; 70:4609-20. [PMID: 12117974 PMCID: PMC128195 DOI: 10.1128/iai.70.8.4609-4620.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Fusobacterium necrophorum, a gram-negative, rod-shaped, anaerobic bacterium, is a primary or secondary etiological agent in a variety of necrotic, purulent infections in humans and animals. Its major virulence factor is leukotoxin, a high-molecular-weight secreted protein, primarily toxic to ruminant leukocytes. In this study, bovine peripheral blood leukocytes were exposed to various concentrations of immunoaffinity-purified leukotoxin and the cytotoxicity was analyzed by flow cytometry and scanning and transmission electron microscopy. At very low toxin concentrations, polymorphonuclear leukocytes (PMNs) showed activation, as indicated by translocation of primary and secondary granules to the periphery of the cytoplasm. Furthermore, these cells showed changes characteristic of apoptosis, including decreased cell size, organelle condensation, cytoplasmic membrane blebbing (zeiosis), and chromatin condensation and margination, and decrease in cellular DNA content. At moderately high concentrations of leukotoxin, bovine mononuclear cells were also induced to undergo programmed cell death. At very high concentrations, leukotoxin caused necrotic cell death of bovine peripheral leukocytes. The ability of F. necrophorum leukotoxin to modulate the host immune system by its toxicity, including cellular activation of PMNs and apoptosis-mediated killing of phagocytes and immune effector cells, represents a potentially important mechanism of its pathogenesis.
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Affiliation(s)
- Sanjeevkumar Narayanan
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA
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Abstract
Leukotoxins are a group of exotoxins that produce their primary toxic effects against leukocytes, especially polymorphonuclear cells (PMNs). Leukotoxins include a variety of chemicals ranging from 9,10-epoxy 12-octadecenoate, a fatty acid derivative secreted by leukocytes themselves, to proteins such as RTX (repeats in toxin). This review focuses on leukotoxins of three species of gram-negative bacteria, Mannheimia (Pasteurella) haemolytica, Actinobacillus actinomycetemcomitans, and Fusobacterium necrophorum.
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Affiliation(s)
- Sanjeev Kumar Narayanan
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, 1800 Denison Avenue, Manhattan, KS 66506-5606, USA
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20
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Narayanan SK, Nagaraja TG, Chengappa MM, Stewart GC. Cloning, sequencing, and expression of the leukotoxin gene from Fusobacterium necrophorum. Infect Immun 2001; 69:5447-55. [PMID: 11500416 PMCID: PMC98656 DOI: 10.1128/iai.69.9.5447-5455.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fusobacterium necrophorum is a gram-negative, rod-shaped, anaerobic bacterium that is a primary or secondary etiological agent in a variety of necrotic purulent infections in animals and humans. Included are diseases of cattle such as liver abscesses and foot rot, which have economically important consequences for the cattle industry. The major virulence factor of this bacterium is leukotoxin, a secreted protein of high molecular weight active against leukocytes from ruminants. The screening of a genomic DNA library with polyclonal antisera raised against native affinity-purified leukotoxin and further extension of the sequence using inverse PCR led to the cloning of the entire leukotoxin gene. The leukotoxin gene open reading frame (ORF; lktA) consists of 9,726 bp and encodes a protein of 3,241 amino acids with an overall molecular weight of 335,956. The leukotoxin does not have sequence similarity with any other bacterial leukotoxin. Five truncated overlapping polypeptides covering the whole lktA ORF were used to immunize rabbits. In Western blot assays, polyclonal antisera raised against all five truncated polypeptides recognized affinity-purified leukotoxin from F. necrophorum culture supernatant in a Western blot assay. Antisera directed against two of the five polypeptides had neutralizing activity against the toxin. The entire leukotoxin ORF was expressed in Escherichia coli. Flow-cytometric analysis showed that the recombinant leukotoxin was active against bovine polymorphonuclear leukocytes and was inhibited with antiserum raised against the F. necrophorum leukotoxin. Southern blot hybridization analysis revealed different patterns of lktA hybridizing bands between isolates of the two subspecies of F. necrophorum.
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Affiliation(s)
- S K Narayanan
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506, USA
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Stokka GL, Lechtenberg K, Edwards T, MacGregor S, Voss K, Griffin D, Grotelueschen DM, Smith RA, Perino LJ. Lameness in feedlot cattle. Vet Clin North Am Food Anim Pract 2001; 17:189-207, viii. [PMID: 11320695 DOI: 10.1016/s0749-0720(15)30062-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This article examines the various causes of lameness in feedlot cattle, with an emphasis on clinical signs, treatment, and prevention. Specific conditions are discussed, including interdigital necrobacillosis, laminitis, feedlot injuries, and feedlot lameness associated with Mycoplasma bovis. Immune management of the foot is also reviewed.
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Affiliation(s)
- G L Stokka
- Kansas State University, Manhattan, Kansas, USA
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