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Zhou Q, Mi K, Ma W, Feng F, Huo M, Sun Y, Huang L. Metagenomic analysis reveals impact of acyl homoserine endolipid-like signaling molecules on the aqueous sediment resistome under florfenicol stress. BIORESOURCE TECHNOLOGY 2024; 395:130318. [PMID: 38219924 DOI: 10.1016/j.biortech.2024.130318] [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: 11/03/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Quorum sensing potentially helps microorganisms adapt to antibiotic stress encountered in the environment. This experiment investigated the effect of acyl homoserine endolipid-like signaling molecules on microbial antibiotic resistance gene structures in aqueous sediments under florfenicol stress. Additional acyl homoserine endolipid-like signaling molecules (AHLs) alter the structure of multidrug resistance genes in florfenicol-stressed sediments, particularly the multidrug resistance efflux pump gene family. Prophages and integrative and conjugative elements (ICEs) determined the resistance genes structure, and pathways related to mobile genetic elements (MGEs) transfer may play an essential role in this process. The practical application of AHLs to regulate quorum sensing systems may alter bacterial stress responses to environmental florfenicol residues, thereby reducing the development of antibiotic resistance in the environment.
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Affiliation(s)
- Qin Zhou
- National Reference Laboratory of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products,Whan 430070, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, China; National Laboratory of Safety Evaluation (Environmental Assessment) of Veterinary Drugs, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China|
| | - Kun Mi
- National Reference Laboratory of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China
| | - Wenjin Ma
- National Reference Laboratory of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, China
| | - Fenglin Feng
- National Laboratory of Safety Evaluation (Environmental Assessment) of Veterinary Drugs, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China|
| | - Meixia Huo
- National Reference Laboratory of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, China
| | - Yongxue Sun
- National Laboratory of Safety Evaluation (Environmental Assessment) of Veterinary Drugs, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China|
| | - Lingli Huang
- National Reference Laboratory of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products,Whan 430070, China; Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430070, China.
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2
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Hao M, Wang M, Zhao D, Shi Y, Yuan Y, Li J, Zhai Y, Liu X, Zhou D, Chen H, Lin P, Tang K, Liu W, Jin Y, Wang A. Alr Gene in Brucella suis S2: Its Role in Lipopolysaccharide Biosynthesis and Bacterial Virulence in RAW264.7. Int J Mol Sci 2023; 24:10744. [PMID: 37445922 DOI: 10.3390/ijms241310744] [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: 06/08/2023] [Revised: 06/24/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Brucella suis, the causative agent of brucellosis, poses a significant public health and animal husbandry threat. However, the role of the alanine racemase (alr) gene, which encodes alanine racemase in Brucella, remains unclear. Here, we analyzed an alr deletion mutant and a complemented strain of Brucella suis S2. The knockout strain displayed an unaltered, smooth phenotype in acriflavine agglutination tests but lacked the core polysaccharide portion of lipopolysaccharide (LPS). Genes involved in the LPS synthesis were significantly upregulated in the deletion mutant. The alr deletion strain exhibited reduced intracellular viability in the macrophages, increased macrophage-mediated killing, and upregulation of the apoptosis markers. Bcl2, an anti-apoptotic protein, was downregulated, while the pro-apoptotic proteins, Bax, Caspase-9, and Caspase-3, were upregulated in the macrophages infected with the deletion strain. The infected macrophages showed increased mitochondrial membrane permeability, Cytochrome C release, and reactive oxygen species, activating the mitochondrial apoptosis pathway. These findings revealed that alanine racemase was dispensable in B. suis S2 but influenced the strain's rough features and triggered the mitochondrial apoptosis pathway during macrophage invasion. The deletion of the alr gene reduced the intracellular survival and virulence. This study enhances our understanding of the molecular mechanism underlying Brucella's survival and virulence and, specifically, how alr gene affects host immune evasion by regulating bacterial LPS biosynthesis.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Ye Yuan
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Huatao Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Pengfei Lin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Keqiong Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
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3
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Shen Y, Gao S, Fan Q, Zuo J, Wang Y, Yi L, Wang Y. New antibacterial targets: Regulation of quorum sensing and secretory systems in zoonotic bacteria. Microbiol Res 2023; 274:127436. [PMID: 37343493 DOI: 10.1016/j.micres.2023.127436] [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: 03/17/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
Quorum sensing (QS) is a communication mechanism that controls bacterial communication and can influence the transcriptional expression of multiple genes through one or more signaling molecules, thereby coordinating the population response of multiple bacterial pathogens. Secretion systems (SS) play an equally important role in bacterial information exchange, relying on the secretory systems to secrete proteins that act as virulence factors to promote adhesion to host cells. Eight highly efficient SS have been described, all of which are involved in the secretion or transfer of virulence factors, and the effector proteins they secrete play a key role in the virulence and pathogenicity of bacteria. It has been shown that many bacterial SS are directly or indirectly regulated by QS and thus influence bacterial virulence and antibiotic resistance. This review describes the relationship between QS and SS of several common zoonotic pathogenic bacteria and outlines the molecular mechanisms of how QS systems regulate SS, to provide a theoretical basis for the study of bacterial pathogenicity and the development of novel antibacterial drugs.
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Affiliation(s)
- Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China
| | - Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Jing Zuo
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Li Yi
- Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China; College of Life Science, Luoyang Normal University, Luoyang, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China.
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4
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English BC, Savage HP, Mahan SP, Diaz-Ochoa VE, Young BM, Abuaita BH, Sule G, Knight JS, O’Riordan MX, Bäumler AJ, Tsolis RM. The IRE1α-XBP1 Signaling Axis Promotes Glycolytic Reprogramming in Response to Inflammatory Stimuli. mBio 2023; 14:e0306822. [PMID: 36475773 PMCID: PMC9973330 DOI: 10.1128/mbio.03068-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
Immune cells must be able to adjust their metabolic programs to effectively carry out their effector functions. Here, we show that the endoplasmic reticulum (ER) stress sensor Inositol-requiring enzyme 1 alpha (IRE1α) and its downstream transcription factor X box binding protein 1 (XBP1) enhance the upregulation of glycolysis in classically activated macrophages (CAMs). The IRE1α-XBP1 signaling axis supports this glycolytic switch in macrophages when activated by lipopolysaccharide (LPS) stimulation or infection with the intracellular bacterial pathogen Brucella abortus. Importantly, these different inflammatory stimuli have distinct mechanisms of IRE1α activation; while Toll-like receptor 4 (TLR4) supports glycolysis under both conditions, TLR4 is required for activation of IRE1α in response to LPS treatment but not B. abortus infection. Though IRE1α and XBP1 are necessary for maximal induction of glycolysis in CAMs, activation of this pathway is not sufficient to increase the glycolytic rate of macrophages, indicating that the cellular context in which this pathway is activated ultimately dictates the cell's metabolic response and that IRE1α activation may be a way to fine-tune metabolic reprogramming. IMPORTANCE The immune system must be able to tailor its response to different types of pathogens in order to eliminate them and protect the host. When confronted with bacterial pathogens, macrophages, frontline defenders in the immune system, switch to a glycolysis-driven metabolism to carry out their antibacterial functions. Here, we show that IRE1α, a sensor of ER stress, and its downstream transcription factor XBP1 support glycolysis in macrophages during infection with Brucella abortus or challenge with Salmonella LPS. Interestingly, these stimuli activate IRE1α by independent mechanisms. While the IRE1α-XBP1 signaling axis promotes the glycolytic switch, activation of this pathway is not sufficient to increase glycolysis in macrophages. This study furthers our understanding of the pathways that drive macrophage immunometabolism and highlights a new role for IRE1α and XBP1 in innate immunity.
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Affiliation(s)
- Bevin C. English
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Hannah P. Savage
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Scott P. Mahan
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Vladimir E. Diaz-Ochoa
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Briana M. Young
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Gautam Sule
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason S. Knight
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mary X. O’Riordan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Andreas J. Bäumler
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Renée M. Tsolis
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
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5
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Metagenomic insights into taxonomic, functional diversity and inhibitors of microbial biofilms. Microbiol Res 2022; 265:127207. [DOI: 10.1016/j.micres.2022.127207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/17/2022] [Accepted: 09/18/2022] [Indexed: 11/21/2022]
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6
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Tian M, Li Z, Qu J, Fang T, Yin Y, Zuo D, Abdelgawad HA, Hu H, Wang S, Qi J, Wang G, Yu S. The novel LysR-family transcriptional regulator BvtR is involved in the resistance of Brucella abortus to nitrosative stress, detergents and virulence through the genetic regulation of diverse pathways. Vet Microbiol 2022; 267:109393. [PMID: 35259600 DOI: 10.1016/j.vetmic.2022.109393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/22/2022] [Accepted: 02/28/2022] [Indexed: 11/22/2022]
Abstract
Brucella is a facultative intracellular bacterium lacking classical virulence factors; its virulence instead depends on its ability to invade and proliferate within host cells. After entering cells, Brucella rapidly modulates the expression of a series of genes involved in metabolism and immune evasion. Here, a novel LysR-family transcriptional regulator, designated Brucellavirulence-related transcriptional regulator (BvtR), was found to be associated with Brucella abortus virulence. We first successfully constructed a BvtR mutant, ΔbvtR, and a complemented strain, ΔbvtR-Com. Subsequently, we performed cell infection experiments, which indicated that the ΔbvtR strain exhibited similar adhesion, invasion and survival within HeLa cells or RAW264.7 macrophages to those of the wild-type strain. In stress resistance tests, the ΔbvtR strain showed enhanced sensitivity to sodium nitroprusside and sodium dodecyl sulfate, but not to hydrogen peroxide, cumene hydroperoxide, polymyxin B and natural serum. Mouse infection experiments indicated that the virulence of the ΔbvtR strain significantly decreased at 4 weeks post-infection. Finally, we analyzed differentially expressed genes regulated by BvtR with RNA-seq, COG classification and KEGG pathway analysis. Nitrogen metabolism, siderophore biosynthesis and oligopeptide transport were found to be the predominantly altered functions, and key metabolic and regulatory networks were delineated in the ΔbvtR mutant. Thus, we identified a novel Brucella virulence-related regulator, BvtR, and demonstrated that BvtR regulation affects Brucella resistance to killing by sodium nitroprusside and sodium dodecyl sulfate. The differentially expressed genes responding to BvtR are involved in diverse functions or pathways in Brucella, thus, suggesting the breadth of BvtR's regulatory functions. This study provides novel clues regarding Brucella pathogenesis.
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Affiliation(s)
- Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Zichen Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jing Qu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; Songjiang District Center for Animal Disease Control and Prevention, Shanghai 201699, China
| | - Tian Fang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Yi Yin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Dong Zuo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hosny Ahmed Abdelgawad
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Guijun Wang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China.
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7
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Hiyoshi H, English BC, Diaz-Ochoa VE, Wangdi T, Zhang LF, Sakaguchi M, Haneda T, Tsolis RM, Bäumler AJ. Virulence factors perforate the pathogen-containing vacuole to signal efferocytosis. Cell Host Microbe 2022; 30:163-170.e6. [PMID: 34951948 PMCID: PMC8831471 DOI: 10.1016/j.chom.2021.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/20/2021] [Accepted: 11/30/2021] [Indexed: 12/11/2022]
Abstract
Intracellular pathogens commonly reside within macrophages to find shelter from humoral defenses, but host cell death can expose them to the extracellular milieu. We find intracellular pathogens solve this dilemma by using virulence factors to generate a complement-dependent find-me signal that initiates uptake by a new phagocyte through efferocytosis. During macrophage death, Salmonella uses a type III secretion system to perforate the membrane of the pathogen-containing vacuole (PCV), thereby triggering complement deposition on bacteria entrapped in pore-induced intracellular traps (PITs). In turn, complement activation signals neutrophil efferocytosis, a process that shelters intracellular bacteria from the respiratory burst. Similarly, Brucella employs its type IV secretion system to perforate the PCV membrane, which induces complement deposition on bacteria entrapped in PITs. Collectively, this work identifies virulence factor-induced perforation of the PCV as a strategy of intracellular pathogens to generate a find-me signal for efferocytosis.
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Affiliation(s)
- Hirotaka Hiyoshi
- Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Bevin C English
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Vladimir E Diaz-Ochoa
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Tamding Wangdi
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Lillian F Zhang
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Miako Sakaguchi
- Central Laboratory, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Takeshi Haneda
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Renée M Tsolis
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, University of California at Davis, One Shields Ave, Davis, CA 95616, USA.
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8
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Xiong X, Li B, Zhou Z, Gu G, Li M, Liu J, Jiao H. The VirB System Plays a Crucial Role in Brucella Intracellular Infection. Int J Mol Sci 2021; 22:ijms222413637. [PMID: 34948430 PMCID: PMC8707931 DOI: 10.3390/ijms222413637] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a highly prevalent zoonotic disease caused by Brucella. Brucella spp. are gram-negative facultative intracellular parasitic bacteria. Its intracellular survival and replication depend on a functional virB system, an operon encoded by VirB1–VirB12. Type IV secretion system (T4SS) encoded by the virB operon is an important virulence factor of Brucella. It can subvert cellular pathway and induce host immune response by secreting effectors, which promotes Brucella replication in host cells and induce persistent infection. Therefore, this paper summarizes the function and significance of the VirB system, focusing on the structure of the VirB system where VirB T4SS mediates biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV), the effectors of T4SS and the cellular pathways it subverts, which will help better understand the pathogenic mechanism of Brucella and provide new ideas for clinical vaccine research and development.
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Affiliation(s)
- Xue Xiong
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Bowen Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Zhixiong Zhou
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Guojing Gu
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Mengjuan Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Jun Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Yujinxiang Street 573, Changchun 130122, China
- Correspondence: (J.L.); (H.J.)
| | - Hanwei Jiao
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
- National Center of Technology Innovation for Pigs, Chongqing 402460, China
- Veterinary Scientific Engineering Research Center, Chongqing 402460, China
- Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China
- Correspondence: (J.L.); (H.J.)
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9
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Stranahan LW, Arenas-Gamboa AM. When the Going Gets Rough: The Significance of Brucella Lipopolysaccharide Phenotype in Host-Pathogen Interactions. Front Microbiol 2021; 12:713157. [PMID: 34335551 PMCID: PMC8319746 DOI: 10.3389/fmicb.2021.713157] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/22/2021] [Indexed: 01/18/2023] Open
Abstract
Brucella is a facultatively intracellular bacterial pathogen and the cause of worldwide zoonotic infections, infamous for its ability to evade the immune system and persist chronically within host cells. Despite the frequent association with attenuation in other Gram-negative bacteria, a rough lipopolysaccharide phenotype is retained by Brucella canis and Brucella ovis, which remain fully virulent in their natural canine and ovine hosts, respectively. While these natural rough strains lack the O-polysaccharide they, like their smooth counterparts, are able to evade and manipulate the host immune system by exhibiting low endotoxic activity, resisting destruction by complement and antimicrobial peptides, entering and trafficking within host cells along a similar pathway, and interfering with MHC-II antigen presentation. B. canis and B. ovis appear to have compensated for their roughness by alterations to their outer membrane, especially in regards to outer membrane proteins. B. canis, in particular, also shows evidence of being less proinflammatory in vivo, suggesting that the rough phenotype may be associated with an enhanced level of stealth that could allow these pathogens to persist for longer periods of time undetected. Nevertheless, much additional work is required to understand the correlates of immune protection against the natural rough Brucella spp., a critical step toward development of much-needed vaccines. This review will highlight the significance of rough lipopolysaccharide in the context of both natural disease and host–pathogen interactions with an emphasis on natural rough Brucella spp. and the implications for vaccine development.
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Affiliation(s)
- Lauren W Stranahan
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Angela M Arenas-Gamboa
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
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10
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Characteristics of Brucella abortus vaccine strain A19 reveals its potential mechanism of attenuated virulence. Vet Microbiol 2021; 254:109007. [PMID: 33582483 DOI: 10.1016/j.vetmic.2021.109007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/02/2021] [Indexed: 11/22/2022]
Abstract
Brucella vaccination is one of the most important strategies for controlling brucellosis in livestock. The A19 strain was the effective vaccine used to control brucellosis in China. However, the characteristics of physiological and attenuated virulence of the A19 strain are not investigated in detail. In this study, we compared the phenotypic characteristics of the A19 to the wild-type strain S2308. Virulence test showed that the A19 was significantly attenuated at chronic infection stage in infected mouse model. In growth analysis, the A19 exhibited a quick growth at exponential phase and premature at stationary phase. The inflammatory response of macrophages infected by the A19 was detected using TaqMan qPCR assay, indicating that the inflammatory level of the A19-infected macrophages was higher than that of the S2308 infection. Cell death analysis showed that the A19 was not cytotoxic for macrophages. Cell infection showed that the A19 reduced its ability to invade, survive and traffic within host cells, and the intracellular A19 hardly excludes lysosome-associated marker LAMP-1, suggesting that the A19 can't escape the lysosome degradation within host cells. In further study, the sensitivity test exhibited that the A19 is more sensitive to stress and bactericidal factors than the S2308 strain, Western blot and silver staining analysis exhibited that the A19 has a different expression pattern of OMPs and reduces LPS O-antigen expression relative to the S2308 strain. Those data give us a more detailed understanding about the A19 vaccine strain, which will be beneficial for improvement of current Brucella vaccine and overcoming its defects.
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11
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Shalby NA, Abo El-Maaty AM, Ali AH, Elgioushy M. Acute phase biomarkers, oxidants, antioxidants, and trace minerals of mobile sheep flocks naturally infected with brucellosis. BULGARIAN JOURNAL OF VETERINARY MEDICINE 2021. [DOI: 10.15547/bjvm.2020-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study assayed the acute phase responses of sheep seropositive to Brucella. Sera collected from ewes (n=160) were subjected to serological tests of Brucella, Rose Bengal plate agglutination test (RBPAT), buffer acidified plate agglutination test (BAPAT), and complement fixation test (CFT). Results revealed that CFT was the most predictive test of brucellosis followed by BAPAT then RBPAT. The moderate predictive blood biochemical parameters were zinc and ascorbic acid. Ewes with low CFT titre (chronic) had low fibrinogen, copper, NO, and GPx. Seropositive animals had high blood concentrations of ascorbic acid and zinc.
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Affiliation(s)
- N. A. Shalby
- Animal Health Research Institute, Agriculture Research center, Dokki, Giza, Egypt
| | - A. M. Abo El-Maaty
- Animal Reproduction and Artificial Insemination, Veterinary Research Division, National Research Centre, Dokki, Giza (Reproductive Physiology), Egypt
| | - A. H. Ali
- Animal Reproduction and Artificial Insemination, Veterinary Research Division, National Research Centre, Dokki, Giza (Reproductive Physiology), Egypt
| | - M. Elgioushy
- Department of Animal Medicine, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
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12
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A rough Brucella mutant induced macrophage death depends on secretion activity of T4SS, but not on cellular Txnip- and Caspase-2-mediated signaling pathway. Vet Microbiol 2020; 244:108648. [PMID: 32402333 DOI: 10.1016/j.vetmic.2020.108648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/03/2020] [Accepted: 03/17/2020] [Indexed: 12/30/2022]
Abstract
Brucella is a facultative intracellular bacterium, dividing into smooth- and rough-type Brucella. Smooth-type Brucella can dissociate into rough mutants with cytotoxicity for macrophages during infection, which is critical for Brucella egress and dissemination. However, the mechanism of cytotoxicity infected by rough Brucella is incomplete. In this study, we verified that a rough-type Brucella (RB14 strain) was cytotoxic for macrophages dependent on Type IV secretion system (T4SS). Two specific T4SS VirB4 and VirB11 mutants were constructed, which affect the secretion of T4SS effectors, but not the expression of T4SS components. Cytotoxicity analysis showed that RB14- induced macrophages death depends on T4SS secretion activity. In a further study, 15 reported T4SS effectors were evaluated in inducing macrophage death using over-expression and transfection methods, the results showed that 15 recombinant strains with over-expression of respective effector were not cytotoxicity. In addition, 10 effectors transfected individually, or co-transfected with five effectors barely induced macrophage death, suggesting that all 15 effectors were not associated with macrophage death. Besides, we also evaluated endoplasmic reticulum (ER) stress, Txnip- or Caspase-2 roles in RB14-induced macrophages death. The results showed that inhibition of ER stress, Caspase or Caspase-2 activation was not associated with RB14-infected macrophages death. The casp2 and txnip knockout cells also showed death when infected by the RB14 strain. In all, the RB14-induced macrophage death depends on the secretion activity of T4SS, but not on ER stress, Txnip- or Caspase-2 signal pathway. This study provides a deep insight for rough Brucella-induced macrophage death, which favors for elucidating Brucella infection lifecycle.
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Zhao X, Yu Z, Ding T. Quorum-Sensing Regulation of Antimicrobial Resistance in Bacteria. Microorganisms 2020; 8:E425. [PMID: 32192182 PMCID: PMC7143945 DOI: 10.3390/microorganisms8030425] [Citation(s) in RCA: 170] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/16/2020] [Accepted: 03/16/2020] [Indexed: 01/21/2023] Open
Abstract
Quorum sensing is a cell-to-cell communication system that exists widely in the microbiome and is related to cell density. The high-density colony population can generate a sufficient number of small molecule signals, activate a variety of downstream cellular processes including virulence and drug resistance mechanisms, tolerate antibiotics, and harm the host. This article gives a general introduction to the current research status of microbial quorum-sensing systems, focuses on the role of quorum-sensing systems in regulating microbial resistance mechanisms, such as drug efflux pump and microbial biofilm formation regulation, and discusses a new strategy for the treatment of drug-resistant bacteria proposed by using quorum quenching to prevent microbial resistance.
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Affiliation(s)
- Xihong Zhao
- Research Center for Environmental Ecology and Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemistry Technology, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430205, China; (X.Z.); (Z.Y.)
| | - Zixuan Yu
- Research Center for Environmental Ecology and Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemistry Technology, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430205, China; (X.Z.); (Z.Y.)
| | - Tian Ding
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou 310058, China
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14
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Pena RT, Blasco L, Ambroa A, González-Pedrajo B, Fernández-García L, López M, Bleriot I, Bou G, García-Contreras R, Wood TK, Tomás M. Relationship Between Quorum Sensing and Secretion Systems. Front Microbiol 2019; 10:1100. [PMID: 31231316 PMCID: PMC6567927 DOI: 10.3389/fmicb.2019.01100] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 01/15/2023] Open
Abstract
Quorum sensing (QS) is a communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation, virulence factor expression, production of secondary metabolites and stress adaptation mechanisms such as bacterial competition systems including secretion systems (SS). These SS have an important role in bacterial communication. SS are ubiquitous; they are present in both Gram-negative and Gram-positive bacteria and in Mycobacterium sp. To date, 8 types of SS have been described (T1SS, T2SS, T3SS, T4SS, T5SS, T6SS, T7SS, and T9SS). They have global functions such as the transport of proteases, lipases, adhesins, heme-binding proteins, and amidases, and specific functions such as the synthesis of proteins in host cells, adaptation to the environment, the secretion of effectors to establish an infectious niche, transfer, absorption and release of DNA, translocation of effector proteins or DNA and autotransporter secretion. All of these functions can contribute to virulence and pathogenesis. In this review, we describe the known types of SS and discuss the ones that have been shown to be regulated by QS. Due to the large amount of information about this topic in some pathogens, we focus mainly on Pseudomonas aeruginosa and Vibrio spp.
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Affiliation(s)
- Rocio Trastoy Pena
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Lucia Blasco
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Antón Ambroa
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Laura Fernández-García
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Maria López
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Ines Bleriot
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - German Bou
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Thomas Keith Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Maria Tomás
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
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15
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Li P, Tian M, Hu H, Yin Y, Guan X, Ding C, Wang S, Yu S. Lable-free based comparative proteomic analysis of secretory proteins of rough Brucella mutants. J Proteomics 2019; 195:66-75. [PMID: 30659936 DOI: 10.1016/j.jprot.2019.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/07/2019] [Accepted: 01/13/2019] [Indexed: 01/18/2023]
Abstract
Brucella rough mutants are reported to induce infected macrophage death, which is type IV secretion system (T4SS) dependent. T4SS and its secretory proteins play a major role in host-bacteria interactions, but the crucial secretory proteins to promote macrophage death during Brucella rough mutant infection have not been characterized. In this study, we found that T4SS components played no role for macrophage death induced by Brucella rough mutant infection, but some T4SS effectors did. Proteomics of secretory proteins from Brucella rough mutants ΔrfbE and ΔrfbEΔvirB123 was analyzed by liquid chromatography/tandem mass spectrometry and 861 unique proteins were identified, among which 37 were differential secretory proteins. Gene ontology and pathway analysis showed that differential secretory proteins involved in cellular process and metabolic process, distributed in the cell and membrane, possessed molecular function of catalytic activity and binding, and were associated with ribosome, NOD-like receptor signaling pathway, two-component system and bacterial secretion system. Cell death analysis showed that T4SS effector VceC, and two differential secretory proteins OmpW family protein (BAB1_1579) and protein BAB1_1185 were associated with Brucella cytotoxicity. This study provides new insights into the molecular mechanisms associated with Brucella cytotoxicity and valuable information for screening vaccine candidates for Brucella. SIGNIFICANCE: Brucella rough mutants induce infected macrophage death, which is T4SS dependent. In the present report, a comparative proteomics analysis revealed 37 differential secretory proteins between Brucella rough mutants ΔrfbE and ΔrfbEΔvirB123. Further study demonstrated OmpW family protein (BAB1_1579) and uncharacterized protein BAB1_1185, two differential secretory proteins, were associated with Brucella cytotoxicity. This study provides novel information of the secretory proteins from the Brucella rough mutants and their effects on the Brucella cytotoxicity.
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Affiliation(s)
- Peng Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Yi Yin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Xiang Guan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou, PR China.
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16
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Tian M, Lian Z, Bao Y, Bao S, Yin Y, Li P, Ding C, Wang S, Li T, Qi J, Wang X, Yu S. Identification of a novel, small, conserved hypothetical protein involved inBrucella abortusvirulence by modifying the expression of multiple genes. Transbound Emerg Dis 2018; 66:349-362. [DOI: 10.1111/tbed.13028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/05/2018] [Accepted: 09/21/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Mingxing Tian
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Zhengmin Lian
- China College of Veterinary Medicine Gansu Agricultural University LanzhouChina
| | - Yanqing Bao
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Shijun Bao
- China College of Veterinary Medicine Gansu Agricultural University LanzhouChina
| | - Yi Yin
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Peng Li
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Chan Ding
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Tao Li
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Xiaolan Wang
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute Chinese Academy of Agricultural Sciences (CAAS) Shanghai China
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17
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Tian M, Bao Y, Li P, Hu H, Ding C, Wang S, Li T, Qi J, Wang X, Yu S. The putative amino acid ABC transporter substrate-binding protein AapJ2 is necessary for Brucella virulence at the early stage of infection in a mouse model. Vet Res 2018; 49:32. [PMID: 29598830 PMCID: PMC5874993 DOI: 10.1186/s13567-018-0527-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/12/2018] [Indexed: 01/17/2023] Open
Abstract
Brucellosis is a zoonotic bacterial disease caused by Brucella spp. The virulence of these bacteria is dependent on their ability to invade and replicate within host cells. In a previous study, a putative gene bab_RS27735 encoding an amino acid ABC transporter substrate-binding protein homologous to AapJ protein was found to be involved in Brucella abortus virulence. In this study, we successfully constructed a bab_RS27735 deletion mutant, Δ27735. Compared with the wild-type strain, the lipopolysaccharide pattern of the mutant was not changed, but the growth ability was slightly defected in the exponential phase. In tolerance tests, sensitivity of the Δ27735 mutant to oxidative stress, bactericidal peptides or low pH was not different from that of the wild-type strain. Cell infection assay showed that the mutant was reduced survival within macrophages but could efficiently escape lysosome degradation. The results of a virulence test showed that the Δ27735 mutant was attenuated in a mouse model at the early stage of infection but recovered its virulence at the late stage of infection. Meanwhile, the development of splenomegaly and histopathological lesions was observed in mice infected with either the wild-type strain or the mutant. These results are in line with the release of IL-12p40 and TNF-α into the peripheral blood of infected mice. Besides, expression of diverse genes was up-regulated in the Δ27735 mutant, which may contribute to the reduced virulence of the mutant. These data elucidated that the bab_RS27735 gene is necessary for B. abortus virulence at the early stage of infection in a mouse model.
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Affiliation(s)
- Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Yanqing Bao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Peng Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Tao Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Xiaolan Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, 200241, China.
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