1
|
Sun J, Wen S, Wang Z, Liu W, Lin Y, Gu J, Mao W, Xu X, He Q, Cai X. Glaesserella parasuis QseBC two-component system senses epinephrine and regulates capD expression. Microbiol Spectr 2023; 11:e0150823. [PMID: 37882555 PMCID: PMC10714720 DOI: 10.1128/spectrum.01508-23] [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: 04/10/2023] [Accepted: 09/16/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The key bacterial pathogen Glaesserella parasuis, which can cause Glässer's disease, has caused significant financial losses to the swine industry worldwide. Capsular polysaccharide (CPS) is an important virulence factor for bacteria, providing the ability to avoid recognition and killing by the host immune system. Exploring the alteration of CPS synthesis in G. parasuis in response to epinephrine stimulation can lay the groundwork for revealing the pathogenic mechanism of G. parasuis as well as providing ideas for Glässer's disease control.
Collapse
Affiliation(s)
- Ju Sun
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Siting Wen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Zhichao Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wei Liu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yan Lin
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jiayun Gu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Weiting Mao
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaojuan Xu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Qigai He
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xuwang Cai
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| |
Collapse
|
2
|
Yan X, Dai K, Gu C, Yu Z, He M, Xiao W, Zhao M, He L. Deletion of two-component system QseBC weakened virulence of Glaesserella parasuis in a murine acute infection model and adhesion to host cells. PeerJ 2022; 10:e13648. [PMID: 35769141 PMCID: PMC9235811 DOI: 10.7717/peerj.13648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/07/2022] [Indexed: 01/17/2023] Open
Abstract
The widespread two-component system (TCS), QseBC, involves vital virulence regulators in Enterobacteriaceae and Pasteurellaceae. Here we studied the function of QseBC in Glaesserella parasuis. A ΔqseBC mutant was constructed using a Glaesserella parasuis serovar 11 clinical strain SC1401 by natural transformation. Immunofluorescence was used to evaluate cellular adhesion, the levels of inflammation and apoptosis. The ability of ΔqseBC and ΔqseC mutant strains to adhere to PAM and MLE-12 cells was significantly reduced. Additionally, by focusing on the clinical signs, H&E, and IFA for inflammation and apoptosis, we found that the ΔqseBC mutant weakened virulence in the murine models. Together, these findings suggest that QseBC plays an important role in the virulence of Glaesserella parasuis.
Collapse
Affiliation(s)
| | - Ke Dai
- Sichuan Agricultural University, Chengdu, China
| | - Congwei Gu
- Southwest Medical University, Luzhou, China
| | - Zehui Yu
- Southwest Medical University, Luzhou, China
| | - Manli He
- Southwest Medical University, Luzhou, China
| | | | | | - Lvqin He
- Southwest Medical University, Luzhou, China
| |
Collapse
|
3
|
Matiašková K, Kavanová L, Kulich P, Gebauer J, Nedbalcová K, Kudláčková H, Tesařík R, Faldyna M. The Role of Antibodies Against the Crude Capsular Extract in the Immune Response of Porcine Alveolar Macrophages to In Vitro Infection of Various Serovars of Glaesserella ( Haemophilus) parasuis. Front Immunol 2021; 12:635097. [PMID: 33968026 PMCID: PMC8101634 DOI: 10.3389/fimmu.2021.635097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
In Glässer’s disease outbreaks, Glaesserella (Haemophilus) parasuis has to overcome the non-specific immune system in the lower respiratory tract, the alveolar macrophages. Here we showed that porcine alveolar macrophages (PAMs) were able to recognize and phagocyte G. parasuis with strain-to-strain variability despite the presence of the capsule in virulent (serovar 1, 5, 12) as well in avirulent strains (serovar 6 and 9). The capsule, outer membrane proteins, virulence-associated autotransporters, cytolethal distending toxins and many other proteins have been identified as virulence factors of this bacterium. Therefore, we immunized pigs with the crude capsular extract (cCE) from the virulent G. parasuis CAPM 6475 strain (serovar 5) and evaluated the role of the anti-cCE/post-vaccinal IgG in the immune response of PAMs to in vitro infection with various G. parasuis strains. We demonstrated the specific binding of the antibodies to the cCE by Western-blotting assay and immunoprecipitation as well as the specific binding to the strain CAPM 6475 in transmission electron microscopy. In the cCE, we identified several virulence-associated proteins that were immunoreactive with IgG isolated from sera of immunized pigs. Opsonization of G. parasuis strains by post-vaccinal IgG led to enhanced phagocytosis of G. parasuis by PAMs at the first two hours of infection. Moreover, opsonization increased the oxidative burst and expression/production of both pro- and anti-inflammatory cytokines. The neutralizing effects of these antibodies on the antioxidant mechanisms of G. parasuis may lead to attenuation of its virulence and pathogenicity in vivo. Together with opsonization of bacteria by these antibodies, the host may eliminate G. parasuis in the infection site more efficiently. Based on these results, the crude capsular extract is a vaccine candidate with immunogenic properties.
Collapse
Affiliation(s)
- Katarína Matiašková
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Lenka Kavanová
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Pavel Kulich
- Department of Pharmacology and Toxicology, Veterinary Research Institute, Brno, Czechia
| | - Jan Gebauer
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Kateřina Nedbalcová
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Hana Kudláčková
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Radek Tesařík
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia
| | - Martin Faldyna
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czechia.,Department of Infectious Diseases and Microbiology, University of Veterinary Sciences, Brno, Czechia
| |
Collapse
|
4
|
Dai K, Yang Z, Ma X, Chang YF, Cao S, Zhao Q, Huang X, Wu R, Huang Y, Xia J, Yan Q, Han X, Ma X, Wen X, Wen Y. Deletion of Polyamine Transport Protein PotD Exacerbates Virulence in Glaesserella (Haemophilus) parasuis in the Form of Non-biofilm-generated Bacteria in a Murine Acute Infection Model. Virulence 2021; 12:520-546. [PMID: 33525975 PMCID: PMC7872090 DOI: 10.1080/21505594.2021.1878673] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Polyamines are small, polycationic molecules with a hydrocarbon backbone and multiple amino groups required for optimal cell growth. The potD gene, belonging to the ABC (ATP-binding cassette) transport system potABCD, encodes the bacterial substrate-binding subunit of the polyamine transport system, playing a pivotal role in bacterial metabolism and growth. The swine pathogen Glaesserella parasuis possesses an intact pot operon, and the studies presented here mainly examined the involvement of PotD in Glaesserella pathogenesis. A potD-deficient mutant was constructed using a virulent G. parasuis strain SC1401 by natural transformation; immuno-electron microscopy was used to identify the subcellular location of native PotD protein; an electron microscope was adopted to inspect biofilm and bacterial morphology; immunofluorescence technique was employed to study cellular adhesion, the levels of inflammation and apoptosis. The TSA++-pre-cultured mutant strain showed a significantly reduced adhesion capacity to PK-15 and MLE-12 cells. Likewise, we also found attenuation in virulence using murine models focusing on the clinical sign, H&E, and IFA for inflammation and apoptosis. However, when the mutant was grown in TSB++, virulence recovered to normal levels, along with a high level of radical oxygen species formation in the host. The expression of PotD could actively stimulate the production of ROS in Raw 264.7. Our data suggested that PotD from G. parasuis has a high binding potential to polyamine, and is essential for the full bacterial virulence within mouse models. However, the virulence of the potD mutant is highly dependent on its TSA++ culture conditions rather than on biofilm-formation.
Collapse
Affiliation(s)
- Ke Dai
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Zhen Yang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Xiaoyu Ma
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University , NY, USA
| | - Sanjie Cao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Qin Zhao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Xiaobo Huang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Rui Wu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Yong Huang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Jing Xia
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Qigui Yan
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Xinfeng Han
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Xiaoping Ma
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Xintian Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| | - Yiping Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University , Chengdu, China
| |
Collapse
|
5
|
Feng S, Chen A, Wang X, Pan Z, Xu S, Yu H, Zhang B, Liao M. The Glaesserella parasuis phosphoglucomutase is partially required for lipooligosaccharide synthesis. Vet Res 2020; 51:97. [PMID: 32736655 PMCID: PMC7393335 DOI: 10.1186/s13567-020-00822-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/21/2020] [Indexed: 11/21/2022] Open
Abstract
Lipooligosaccharides (LOSs) are virulence determinants of Glaesserella parasuis, a pathogen of the respiratory tract of pigs. We previously reported that disruption of the galU or galE gene in G. parasuis results in increased sensitivity to porcine serum, indicating that the galactose catabolism pathway is required for polysaccharide formation in G. parasuis. Here, we evaluated the role of the HAPS_0849 gene in LOS synthesis. The G. parasuis SC096 HAPS_0849 mutant produced a highly truncated LOS molecule, although a small fraction of intact LOS was still observed, and this mutant was found to be more sensitive to serum than the parental strain. HAPS_0849 was overexpressed and purified for biochemical assays, and this protein exhibited phosphoglucomutase (PGM) activity. Heterologous expression of a pgm gene from Escherichia coli in the HAPS_0849 mutant led to restoration of the wild-type LOS glycoform, further demonstrating the PGM function of HAPS_0849 in G. parasuis. The autoagglutination and biofilm formation ability of this strain were also investigated. Disruption of HAPS_0849 led to an increased tendency to autoagglutinate and form more biofilms, and these enhanced phenotypes were observed in the absence of glucose. In addition, LOSs from HAPS_0849, galU and lgtB mutants had similar truncated glycoforms, while LOSs from the galE and lex-1 mutants exhibited another type of defective LOS pattern. These findings imply that HAPS_0849 may function upstream of GalU in the generation of glucose 1-phosphate. In conclusion, our results preliminarily described the functions of HAPS_0849 in G. parasuis, and this gene was partially required for LOS synthesis.
Collapse
Affiliation(s)
- Saixiang Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
| | - Aihua Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xiaobing Wang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhichao Pan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Siqi Xu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Huiwen Yu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Bin Zhang
- College of Life Science and Technology, Southwest Minzu University, Chengdu, China
| | - Ming Liao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
| |
Collapse
|
6
|
Zeng Z, Zhang B, He H, Chen X, Ren Y, Yue H, Tang C. lgtF effects of Haemophilus parasuis LOS induced inflammation through regulation of NF-κB and MAPKs signaling pathways. Microb Pathog 2017; 110:380-384. [PMID: 28716662 DOI: 10.1016/j.micpath.2017.06.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 06/02/2017] [Accepted: 06/22/2017] [Indexed: 11/16/2022]
Abstract
The lgtF gene encodes a glucosyltransferase responsible for adding a glucose to the first sugar of heptose I in the synthesis of lipooligosaccharides (LOS). To study the function of lgtF, we constructed an lgtF mutant (ΔlgtF) from Haemophilus parasuis SC096 using a natural transformation system. A highly purified preparation of LOS from ΔlgtF (ΔlgtF-LOS) exhibited an obvious truncation in structure compared to the LOS of the wild-type SC096 strain (WT-LOS). The ΔlgtF-LOS also displayed a significantly reduced ability to induce inflammatory cytokine mRNA expression of tumor necrosis factor alpha (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6 and IL-8 in porcine alveolar macrophages (PAMs) in comparison with the WT-LOS. Furthermore, we also found that ΔlgtF-LOS-treated cells had significantly decreased phospho-p65 and phospho-p38, and inhibited IκBα degradation. These findings suggested that the lgtF gene mediated LOS induction of pro-inflammatory cytokines in PAMs by regulating the NF-κB and MAPKs signaling pathways during H. parasuis infection.
Collapse
Affiliation(s)
- Ze Zeng
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Bin Zhang
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China.
| | - Huan He
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Xinnuo Chen
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Yupeng Ren
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Hua Yue
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Cheng Tang
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China.
| |
Collapse
|
7
|
Zhou Q, Feng S, Zhang J, Jia A, Yang K, Xing K, Liao M, Fan H. Two Glycosyltransferase Genes of Haemophilus parasuis SC096 Implicated in Lipooligosaccharide Biosynthesis, Serum Resistance, Adherence, and Invasion. Front Cell Infect Microbiol 2016; 6:100. [PMID: 27672622 PMCID: PMC5018477 DOI: 10.3389/fcimb.2016.00100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 08/29/2016] [Indexed: 12/03/2022] Open
Abstract
Haemophilus parasuis is a common opportunistic pathogen known for its ability to colonize healthy piglets and causes Glässer's disease. The lipooligosaccharide (LOS) of H. parasuis is a potential virulence-associated factor. In this study, two putative glycosyltransferases that might be involved in LOS synthesis in H. parasuis SC096 were identified (lgtB and lex-1). Mutants were constructed to investigate the roles of the lgtB and lex-1 genes. The LOS from the ΔlgtB or Δlex-1 mutant showed truncated structure on silver-stained SDS-PAGE gel compared to the wild-type strain. The ΔlgtB and Δlex-1 mutants were significantly more sensitive to 50% porcine serum, displaying 15.0 and 54.46% survival rates, respectively. Complementation of the lex-1 mutant restored the serum-resistant phenotype. Additionally, the ΔlgtB and Δlex-1 strains showed impaired ability to adhere to and invade porcine kidney epithelial cells (PK-15). The above results suggested that the lgtB and lex-1 genes of the H. parasuis SC096 strain participated in LOS synthesis and were involved in serum resistance, adhesion and invasion.
Collapse
Affiliation(s)
- Qi Zhou
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Saixiang Feng
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Jianmin Zhang
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Aiqing Jia
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Haid Institute of Animal Husbandry and VeterinaryGuangzhou, China
| | - Kaijie Yang
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Kaixiang Xing
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Ming Liao
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| | - Huiying Fan
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University Guangzhou, China
| |
Collapse
|
8
|
Zhang B, Yu Y, Zeng Z, Ren Y, Yue H. Deletion of the rfaE gene in Haemophilus parasuis SC096 strain attenuates serum resistance, adhesion and invasion. Microb Pathog 2014; 74:33-7. [PMID: 25078003 DOI: 10.1016/j.micpath.2014.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 06/20/2014] [Accepted: 07/21/2014] [Indexed: 11/27/2022]
Abstract
In Haemophilus parasuis, the lipooligosaccharide (LOS) has been identified as an important virulence factor. The rfa gene cluster encodes enzymes for LOS core biosynthesis. In order to investigate the role of the rfaE gene, we generated an rfaE deficient mutant (ΔrfaE) of a H. parasuis SC096 by a natural transformation method. The purified preparation of LOS from the ΔrfaE mutant strain showed truncated LOS structure on silver-stained SDS-PAGE. Compared to the wild-type SC096 strain, the generation time of ΔrfaE mutant strain was significantly extended from 59 min to 69 min. The ΔrfaE mutant strain caused an approximately 30-fold reductions in survival rate in 50% sera and 36-fold reductions in survival rate in 90% sera, respectively (p < 0.001). In adhesion and invasion assays, the ΔrfaE mutant strain had 10-fold less efficient adherence and 12-fold reductions in invasion of the porcine umbilicus vein endothelial cells (PUVEC) and porcine kidney epithelial cells (PK-15), respectively (p < 0.001). However, the complemented strain could restore the above phenotypes. Hence, the above results suggested that the rfaE gene participated in the pathogenicity of H. parasuis SC096 strain.
Collapse
Affiliation(s)
- Bin Zhang
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Yuandi Yu
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Ze Zeng
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Yupeng Ren
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China
| | - Hua Yue
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, China.
| |
Collapse
|
9
|
Costa-Hurtado M, Aragon V. Advances in the quest for virulence factors of Haemophilus parasuis. Vet J 2013; 198:571-6. [DOI: 10.1016/j.tvjl.2013.08.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 08/20/2013] [Accepted: 08/25/2013] [Indexed: 10/26/2022]
|
10
|
Gene content and diversity of the loci encoding biosynthesis of capsular polysaccharides of the 15 serovar reference strains of Haemophilus parasuis. J Bacteriol 2013; 195:4264-73. [PMID: 23873912 DOI: 10.1128/jb.00471-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Haemophilus parasuis is the causative agent of Glässer's disease, a systemic disease of pigs, and is also associated with pneumonia. H. parasuis can be classified into 15 different serovars. Here we report, from the 15 serotyping reference strains, the DNA sequences of the loci containing genes for the biosynthesis of the group 1 capsular polysaccharides, which are potential virulence factors of this bacterium. We contend that these loci contain genes for polysaccharide capsule structures, and not a lipopolysaccharide O antigen, supported by the fact that they contain genes such as wza, wzb, and wzc, which are associated with the export of polysaccharide capsules in the current capsule classification system. A conserved region at the 3' end of the locus, containing the wza, ptp, wzs, and iscR genes, is consistent with the characteristic export region 1 of the model group 1 capsule locus. A potential serovar-specific region (region 2) has been found by comparing the predicted coding sequences (CDSs) in all 15 loci for synteny and homology. The region is unique to each reference strain with the exception of those in serovars 5 and 12, which are identical in terms of gene content. The identification and characterization of this locus among the 15 serovars is the first step in understanding the genetic, molecular, and structural bases of serovar specificity in this poorly studied but important pathogen and opens up the possibility of developing an improved molecular serotyping system, which would greatly assist diagnosis and control of Glässer's disease.
Collapse
|