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Han XY, Du LF, Lin ZT, Li C, Xiong T, Zhu WJ, Ye RZ, Wang N, Wang YF, Gao WY, Zhao L, Cui XM, Cao WC. Genomic characters of Anaplasma bovis and genetic diversity in China. Emerg Microbes Infect 2024; 13:2323153. [PMID: 38442029 PMCID: PMC10916922 DOI: 10.1080/22221751.2024.2323153] [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: 12/27/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024]
Abstract
The emergence of Anaplasma bovis or A. bovis-like infection in humans from China and the United States of America has raised concern about the public health importance of this pathogen. Although A. bovis has been detected in a wide range of ticks and mammals in the world, no genome of the pathogen is available up to now, which has prohibited us from better understanding the genetic basis for its pathogenicity. Here we describe an A. bovis genome from metagenomic sequencing of an infected goat in China. Anaplasma bovis had the smallest genome of the genus Anaplasma, and relatively lower GC content. Phylogenetic analysis of single-copy orthologue sequence showed that A. bovis was closely related to A. platys and A. phagocytophilum, but relatively far from intraerythrocytic Anaplasma species. Anaplasma bovis had 116 unique orthogroups and lacked 51 orthogroups in comparison to other Anaplasma species. The virulence factors of A. bovis were significantly less than those of A. phagocytophilum, suggesting less pathogenicity of A. bovis. When tested by specific PCR assays, A. bovis was detected in 23 of 29 goats, with an infection rate up to 79.3% (95% CI: 64.6% ∼94.1%). The phylogenetic analyses based on partial 16S rRNA, gltA and groEL genes indicated that A. bovis had high genetic diversity. The findings of this study lay a foundation for further understanding of the biological characteristics and genetic diversity of A. bovis, and will facilitate the formulation of prevention and control strategies.
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Affiliation(s)
- Xiao-Yu Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Li-Feng Du
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Zhe-Tao Lin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Cheng Li
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Tao Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Wen-Jie Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Run-Ze Ye
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Ning Wang
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Yi-Fei Wang
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Wan-Ying Gao
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Lin Zhao
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, People’s Republic of China
| | - Xiao-Ming Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
| | - Wu-Chun Cao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, People’s Republic of China
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2
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Zhang Q, Peng L, Han W, Chen H, Tang H, Chen X, Langford PR, Huang Q, Zhou R, Li L. The morphology and metabolic changes of Actinobacillus pleuropneumoniae during its growth as a biofilm. Vet Res 2023; 54:42. [PMID: 37237397 PMCID: PMC10224306 DOI: 10.1186/s13567-023-01173-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/23/2023] [Indexed: 05/28/2023] Open
Abstract
Actinobacillus pleuropneumoniae is an important swine respiratory pathogen. Previous studies have suggested that growth as a biofilm is a natural state of A. pleuropneumoniae infection. To understand the survival features involved in the biofilm state, the growth features, morphology and gene expression profiles of planktonic and biofilm A. pleuropneumoniae were compared. A. pleuropneumoniae in biofilms showed reduced viability but maintained the presence of extracellular polymeric substances (EPS) after late log-phase. Under the microscope, bacteria in biofilms formed dense aggregated structures that were connected by abundant EPS, with reduced condensed chromatin. By construction of Δpga and ΔdspB mutants, polymeric β-1,6-linked N-acetylglucosamine and dispersin B were confirmed to be critical for normal biofilm formation. RNA-seq analysis indicated that, compared to their planktonic counterparts, A. pleuropneumoniae in biofilms had an extensively altered transcriptome. Carbohydrate metabolism, energy metabolism and translation were significantly repressed, while fermentation and genes contributing to EPS synthesis and translocation were up-regulated. The regulators Fnr (HlyX) and Fis were found to be up-regulated and their binding motifs were identified in the majority of the differentially expressed genes, suggesting their coordinated global role in regulating biofilm metabolism. By comparing the transcriptome of wild-type biofilm and Δpga, the utilization of oligosaccharides, iron and sulfur and fermentation were found to be important in adhesion and aggregation during biofilm formation. Additionally, when used as inocula, biofilm bacteria showed reduced virulence in mouse, compared with planktonic grown cells. Thus, these results have identified new facets of A. pleuropneumoniae biofilm maintenance and regulation.
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Affiliation(s)
- Qiuhong Zhang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Lu Peng
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Weiyao Han
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Hongyu Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Hao Tang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
| | - Xiabing Chen
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, 430070, Hubei, China
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London, W2 1PG, UK
| | - Qi Huang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
- International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, 430070, Hubei, China
| | - Rui Zhou
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China
- International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, 430070, Hubei, China
| | - Lu Li
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China.
- International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, 430070, Hubei, China.
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3
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Nahar N, Tram G, Jen FEC, Phillips ZN, Weinert L, Bossé J, Jabbari J, Gouil Q, Du MM, Ritchie M, Bowden R, Langford P, Tucker A, Jennings M, Turni C, Blackall P, Atack J. Actinobacillus pleuropneumoniae encodes multiple phase-variable DNA methyltransferases that control distinct phasevarions. Nucleic Acids Res 2023; 51:3240-3260. [PMID: 36840716 PMCID: PMC10123105 DOI: 10.1093/nar/gkad091] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/26/2023] Open
Abstract
Actinobacillus pleuropneumoniae is the cause of porcine pleuropneumonia, a severe respiratory tract infection that is responsible for major economic losses to the swine industry. Many host-adapted bacterial pathogens encode systems known as phasevarions (phase-variable regulons). Phasevarions result from variable expression of cytoplasmic DNA methyltransferases. Variable expression results in genome-wide methylation differences within a bacterial population, leading to altered expression of multiple genes via epigenetic mechanisms. Our examination of a diverse population of A. pleuropneumoniae strains determined that Type I and Type III DNA methyltransferases with the hallmarks of phase variation were present in this species. We demonstrate that phase variation is occurring in these methyltransferases, and show associations between particular Type III methyltransferase alleles and serovar. Using Pacific BioSciences Single-Molecule, Real-Time (SMRT) sequencing and Oxford Nanopore sequencing, we demonstrate the presence of the first ever characterised phase-variable, cytosine-specific Type III DNA methyltransferase. Phase variation of distinct Type III DNA methyltransferase in A. pleuropneumoniae results in the regulation of distinct phasevarions, and in multiple phenotypic differences relevant to pathobiology. Our characterisation of these newly described phasevarions in A. pleuropneumoniae will aid in the selection of stably expressed antigens, and direct and inform development of a rationally designed subunit vaccine against this major veterinary pathogen.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Freda E-C Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Zachary N Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Janine T Bossé
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Jafar S Jabbari
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Quentin Gouil
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Mei R M Du
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Matthew E Ritchie
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Rory Bowden
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland 4222, Australia
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4
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Yin WL, Xie ZY, Zeng YH, Zhang J, Long H, Ren W, Zhang X, Cai XN, Huang AY. Two (p)ppGpp Synthetase Genes, relA and spoT, Are Involved in Regulating Cell Motility, Exopolysaccharides Production, and Biofilm Formation of Vibrio alginolyticus. Front Microbiol 2022; 13:858559. [PMID: 35422789 PMCID: PMC9002329 DOI: 10.3389/fmicb.2022.858559] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
The stringent response mediated by the signal molecule (p)ppGpp is involved in response to multiple environmental stresses and control of various physiological processes. Studies have revealed that (p)ppGpp strongly affects the formation and maintenance of several bacterial biofilms. However, the specific regulatory roles of (p)ppGpp in biofilms, especially in the expression of genes related to cell motility and exopolysaccharides (EPSs) production, remain poorly understood. We recently reported two (p)ppGpp synthetase genes relA and spoT from the epizootic pathogen Vibrio alginolyticus. Herein, we found that the (p)ppGpp synthetase genes of V. alginolyticus contributed to biofilm formation at low cell density and biofilm detachment at high cell density, respectively, in polystyrene microtiter plates. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed that the expression levels of both EPSs and motility associated genes were consistent with the development of biofilms. Besides, the (p)ppGpp synthetase gene spoT was found to be closely involved in the regulation of flagellum, smooth/translucent colony morphology and spotty pellicle at the air-liquid interface. Interestingly, pleiotropic phenotypes of ΔrelAΔspoT were similar to that of the rpoN (σ54) deletion mutant. Meanwhile, the absence of (p)ppGpp synthetase genes significantly reduced the expression levels of rpoN at low cell density, suggesting that (p)ppGpp may mediate the formation via positively affecting the alternative sigma factor RpoN. These findings allow us to propose (p)ppGpp as a crucial regulator for biofilm development in V. alginolyticus, in view of the regulatory roles of relA and spoT in cell motility and EPSs production.
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Affiliation(s)
- Wen-Liang Yin
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China
| | - Zhen-Yu Xie
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China.,Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Haikou, China
| | - Yan-Hua Zeng
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
| | - Ju Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China
| | - Hao Long
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
| | - Wei Ren
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China.,Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Haikou, China
| | - Xiang Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China.,Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Haikou, China
| | - Xiao-Ni Cai
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China.,Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Haikou, China
| | - Ai-You Huang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, China.,Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China.,College of Marine Sciences, Hainan University, Haikou, China.,Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Haikou, China
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5
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Syal K, Rs N, Reddy MVNJ. The extended (p)ppGpp family: New dimensions in Stress response. CURRENT RESEARCH IN MICROBIAL SCIENCES 2021; 2:100052. [PMID: 34841343 PMCID: PMC8610335 DOI: 10.1016/j.crmicr.2021.100052] [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: 04/14/2021] [Revised: 07/21/2021] [Accepted: 07/25/2021] [Indexed: 11/30/2022] Open
Abstract
Second messenger (p)ppGpp mediated stress response plays a crucial role in bacterial persistence and multiple drug resistance. In E. coli, (p)ppGpp binds to RNA polymerase and upregulates the transcription of genes essential for stress response while concurrently downregulating the expression of genes critical for growth and metabolism. Recently, the family of alarmone molecules has expanded to pppGpp, ppGpp, pGpp & (pp)pApp as distinct members. These molecules may help in fine-tuning stress responses in different hostile conditions. Do all of these molecules bind to RNA polymerase? Do they compete with each other or complement each other's functions is still not clear. Earlier, others and we have synthesized artificial analogs of (p)ppGpp that inhibited (p)ppGpp synthesis and long-term survival in M. smegmatis and in B. subtilis suggesting that analogs could compete with each other. Understanding the interplay of these molecules will allow deciphering novel pathways that can be potentially subjected to the therapeutic intervention. In this article, we have reviewed newly characterized second messengers and discussed their mode of action. We have also documented the progress made to-date in understanding the molecular basis of regulation of transcription by second messenger ppGpp, pppGpp, and pGpp.
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Affiliation(s)
- Kirtimaan Syal
- Department of Biological Sciences, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India
| | - Neethu Rs
- Department of Biological Sciences, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India
| | - M V N Janardhan Reddy
- Department of Biological Sciences, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India
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6
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Kim K, Islam M, Jung HW, Lim D, Kim K, Lee SG, Park C, Lee JC, Shin M. ppGpp signaling plays a critical role in virulence of Acinetobacter baumannii. Virulence 2021; 12:2122-2132. [PMID: 34375563 PMCID: PMC8366539 DOI: 10.1080/21505594.2021.1961660] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acinetobacter baumannii, a major nosocomial pathogen, survives in diverse hospital environments, and its multidrug resistance is a major concern. The ppGpp-dependent stringent response mediates the reprogramming of genes with diverse functions in several bacteria. We investigated whether ppGpp is involved in A. baumannii’s pathogenesis by examining biofilm formation, surface motility, adhesion, invasion, and mouse infection studies. Transcriptome analysis of early stationary phase cultures revealed 498 differentially-expressed genes (≥ 2-fold change) in a ppGpp-deficient A. baumannii strain; 220 and 278 genes were up and downregulated, respectively. Csu operon expression, important in pilus biosynthesis during early biofilm formation, was significantly reduced in the ppGpp-deficient strain. Our findings suggest that ppGpp signaling influences A. baumannii biofilm formation, surface motility, adherence, and virulence. We showed the association between ppGpp and pathogenicity in A. baumannii for the first time; ppGpp may be a novel antivirulence target in A. baumannii.
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Affiliation(s)
- Kyeongmin Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Maidul Islam
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Hye-Won Jung
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Daejin Lim
- Department of Microbiology, Chonnam National University Medical School, Gwangju South Korea
| | - Kwangsoo Kim
- Department of Microbiology, Chonnam National University Medical School, Gwangju South Korea
| | - Sung-Gwon Lee
- School of Biological Sciences and Technology, Chonnam National University, Gwangju South Korea
| | - Chungoo Park
- School of Biological Sciences and Technology, Chonnam National University, Gwangju South Korea
| | - Je Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
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7
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Yin W, Xu S, Wang Y, Zhang Y, Chou SH, Galperin MY, He J. Ways to control harmful biofilms: prevention, inhibition, and eradication. Crit Rev Microbiol 2020; 47:57-78. [PMID: 33356690 DOI: 10.1080/1040841x.2020.1842325] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Biofilms are complex microbial architectures that encase microbial cells in a matrix comprising self-produced extracellular polymeric substances. Microorganisms living in biofilms are much more resistant to hostile environments than their planktonic counterparts and exhibit enhanced resistance against the microbicides. From the human perspective, biofilms can be classified into beneficial, neutral, and harmful. Harmful biofilms impact food safety, cause plant and animal diseases, and threaten medical fields, making it urgent to develop effective and robust strategies to control harmful biofilms. In this review, we discuss various strategies to control biofilm formation on infected tissues, implants, and medical devices. We classify the current strategies into three main categories: (i) changing the properties of susceptible surfaces to prevent biofilm formation; (ii) regulating signalling pathways to inhibit biofilm formation; (iii) applying external forces to eradicate the biofilm. We hope this review would motivate the development of innovative and effective strategies for controlling harmful biofilms.
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Affiliation(s)
- Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Siyang Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Yiting Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Yuling Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
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8
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Irving SE, Choudhury NR, Corrigan RM. The stringent response and physiological roles of (pp)pGpp in bacteria. Nat Rev Microbiol 2020; 19:256-271. [PMID: 33149273 DOI: 10.1038/s41579-020-00470-y] [Citation(s) in RCA: 187] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 01/10/2023]
Abstract
The stringent response is a stress signalling system mediated by the alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) in response to nutrient deprivation. Recent research highlights the complexity and broad range of functions that these alarmones control. This Review provides an update on our current understanding of the enzymes involved in ppGpp, pppGpp and guanosine 5'-monophosphate 3'-diphosphate (pGpp) (collectively (pp)pGpp) turnover, including those shown to produce pGpp and its analogue (pp)pApp. We describe the well-known interactions with RNA polymerase as well as a broader range of cellular target pathways controlled by (pp)pGpp, including DNA replication, transcription, nucleotide synthesis, ribosome biogenesis and function, as well as lipid metabolism. Finally, we review the role of ppGpp and pppGpp in bacterial pathogenesis, providing examples of how these nucleotides are involved in regulating many aspects of virulence and chronic infection.
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Affiliation(s)
- Sophie E Irving
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Naznin R Choudhury
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Rebecca M Corrigan
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
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9
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Crispim JS, da Silva TF, Sanches NM, da Silva GC, Pereira MF, Rossi CC, Li Y, Terra VS, Vohra P, Wren BW, Langford PR, Bossé JT, Bazzolli DMS. Serovar-dependent differences in Hfq-regulated phenotypes inActinobacillus pleuropneumoniae. Pathog Dis 2020; 78:5936557. [DOI: 10.1093/femspd/ftaa066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/21/2020] [Indexed: 12/28/2022] Open
Abstract
ABSTRACTThe RNA chaperone Hfq regulates diverse processes in numerous bacteria. In this study, we compared phenotypes (growth rate, adherence, response to different stress conditions and virulence in Galleria mellonella) of wild-type (WT) and isogenic hfq mutants of three serovars (1, 8 and 15) of the porcine pathogen Actinobacillus pleuropneumoniae. Similar growth in rich broth was seen for all strains except Ap1∆hfq, which showed slightly reduced growth throughout the 24 h time course, and the complemented Ap8∆hfqC mutant had a prolonged lag phase. Differences were seen between the three serovar WT strains regarding adherence, stress response and virulence in G. mellonella, and deletion of hfq affected some, but not all of these phenotypes, depending on serovar. Complementation by expression of cloned hfq from an endogenous promoter only restored some WT phenotypes, indicating that complex regulatory networks may be involved, and that levels of Hfq may be as important as presence/absence of the protein regarding its contribution to gene regulation. Our results support that Hfq is a pleiotropic global regulator in A. pleuropneumoniae, but serovar-related differences exist. These results highlight the importance of testing multiple strains/serovars within a given species when determining contributions of global regulators, such as Hfq, to expression of complex phenotypes.
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Affiliation(s)
- Josicelli Souza Crispim
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Thyara Ferreira da Silva
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Newton Moreno Sanches
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Giarlã Cunha da Silva
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Monalessa Fábia Pereira
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Ciro César Rossi
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
| | - Yanwen Li
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Vanessa Sofia Terra
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Prerna Vohra
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Brendan W Wren
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Janine T Bossé
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Denise Mara Soares Bazzolli
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária – BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570–900, Brazil
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10
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Basal-Level Effects of (p)ppGpp in the Absence of Branched-Chain Amino Acids in Actinobacillus pleuropneumoniae. J Bacteriol 2020; 202:JB.00640-19. [PMID: 32015147 DOI: 10.1128/jb.00640-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/24/2020] [Indexed: 12/23/2022] Open
Abstract
The (p)ppGpp-mediated stringent response (SR) is a highly conserved regulatory mechanism in bacterial pathogens, enabling adaptation to adverse environments, and is linked to pathogenesis. Actinobacillus pleuropneumoniae can cause damage to the lungs of pigs, its only known natural host. Pig lungs are known to have a low concentration of free branched-chain amino acids (BCAAs) compared to the level in plasma. We had investigated the role for (p)ppGpp in viability and biofilm formation of A. pleuropneumoniae Now, we sought to determine whether (p)ppGpp was a trigger signal for the SR in A. pleuropneumoniae in the absence of BCAAs. Combining transcriptome and phenotypic analyses of the wild type (WT) and an relA spoT double mutant [which does not produce (p)ppGpp], we found that (p)ppGpp could repress de novo purine biosynthesis and activate antioxidant pathways. There was a positive correlation between GTP and endogenous hydrogen peroxide content. Furthermore, the growth, viability, morphology, and virulence were altered by the inability to produce (p)ppGpp. Genes involved in the biosynthesis of BCAAs were constitutively upregulated, regardless of the existence of BCAAs, without accumulation of (p)ppGpp beyond a basal level. Collectively, our study shows that the absence of BCAAs was not a sufficient signal to trigger the SR in A. pleuropneumoniae (p)ppGpp-mediated regulation in A. pleuropneumoniae is different from that described for the model organism Escherichia coli Further work will establish whether the (p)ppGpp-dependent SR mechanism in A. pleuropneumoniae is conserved among other veterinary pathogens, especially those in the Pasteurellaceae family.IMPORTANCE (p)ppGpp is a key player in reprogramming transcriptomes to respond to nutritional challenges. Here, we present transcriptional and phenotypic differences of A. pleuropneumoniae grown in different chemically defined media in the absence of (p)ppGpp. We show that the deprivation of branched-chain amino acids (BCAAs) does not elicit a change in the basal-level (p)ppGpp, but this level is sufficient to regulate the expression of BCAA biosynthesis. The mechanism found in A. pleuropneumoniae is different from that of the model organism Escherichia coli but similar to that found in some Gram-positive bacteria. This study not only broadens the research scope of (p)ppGpp but also further validates the complexity and multiplicity of (p)ppGpp regulation in microorganisms that occupy different biological niches.
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11
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Synthesis of ppGpp impacts type IX secretion and biofilm matrix formation in Porphyromonas gingivalis. NPJ Biofilms Microbiomes 2020; 6:5. [PMID: 32005827 PMCID: PMC6994654 DOI: 10.1038/s41522-020-0115-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/15/2020] [Indexed: 12/15/2022] Open
Abstract
In order to persist, bacteria need to adjust their physiological state in response to external and internal cues. External stimuli are often referred to as stressors. The stringent response, mediated by the alarmone (p)ppGpp, is central to the stress response in many bacteria; yet, there is limited knowledge regarding the role of (p)ppGpp signaling in bacteria belonging to the phylum Bacteroidetes. Like its counterparts in the gut (e.g., Bacteroides thetaiotaomicron and Bacteroides fragilis), Porphyromonas gingivalis persists in close association with its human host. Given the potential for numerous perturbations in the oral cavity, and the fact that P. gingivalis can enter and replicate within host cells, we hypothesized that (p)ppGpp is a key signaling molecule for stress adaptation and persistence. Here, we show that accumulation of ppGpp in P. gingivalis is governed by two homologous enzymes, designated Rel, and RshB, and that ppGpp signaling affects growth rate, survival, biofilm formation, production of outer membrane vesicles, and expression of genes encoding type IX secretion structural and cargo proteins. Overall, our findings provide a potential mechanism by which biofilm formation and virulence of P. gingivalis are integrated via ppGpp signaling, a regulatory mechanism central to bacterial survival in dynamic environments.
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12
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Bennison DJ, Irving SE, Corrigan RM. The Impact of the Stringent Response on TRAFAC GTPases and Prokaryotic Ribosome Assembly. Cells 2019; 8:cells8111313. [PMID: 31653044 PMCID: PMC6912228 DOI: 10.3390/cells8111313] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/17/2019] [Accepted: 10/23/2019] [Indexed: 12/24/2022] Open
Abstract
Many facets of ribosome biogenesis and function, including ribosomal RNA (rRNA) transcription, 70S assembly and protein translation, are negatively impacted upon induction of a nutrient stress-sensing signalling pathway termed the stringent response. This stress response is mediated by the alarmones guanosine tetra- and penta-phosphate ((p)ppGpp), the accumulation of which leads to a massive cellular response that slows growth and aids survival. The 70S bacterial ribosome is an intricate structure, with assembly both complex and highly modular. Presiding over the assembly process is a group of P-loop GTPases within the TRAFAC (Translation Factor Association) superclass that are crucial for correct positioning of both early and late stage ribosomal proteins (r-proteins) onto the rRNA. Often described as 'molecular switches', members of this GTPase superfamily readily bind and hydrolyse GTP to GDP in a cyclic manner that alters the propensity of the GTPase to carry out a function. TRAFAC GTPases are considered to act as checkpoints to ribosome assembly, involved in binding to immature sections in the GTP-bound state, preventing further r-protein association until maturation is complete. Here we review our current understanding of the impact of the stringent response and (p)ppGpp production on ribosome maturation in prokaryotic cells, focusing on the inhibition of (p)ppGpp on GTPase-mediated subunit assembly, but also touching upon the inhibition of rRNA transcription and protein translation.
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Affiliation(s)
- Daniel J Bennison
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | - Sophie E Irving
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | - Rebecca M Corrigan
- The Florey Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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13
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Bifunctional Enzyme SpoT Is Involved in Biofilm Formation of Helicobacter pylori with Multidrug Resistance by Upregulating Efflux Pump Hp1174 ( gluP). Antimicrob Agents Chemother 2018; 62:AAC.00957-18. [PMID: 30181372 PMCID: PMC6201075 DOI: 10.1128/aac.00957-18] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 08/22/2018] [Indexed: 02/06/2023] Open
Abstract
The drug resistance of Helicobacter pylori is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance (MDR) in bacteria. The drug resistance of Helicobacter pylori is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance (MDR) in bacteria. The ability of H. pylori to form biofilms on the gastric mucosa is known. However, there are few studies on the regulatory mechanisms of H. pylori biofilm formation and multidrug resistance. Guanosine 3′-diphosphate 5′-triphosphate and guanosine 3′,5′-bispyrophosphate [(p)ppGpp] are global regulatory factors and are synthesized in H. pylori by the bifunctional enzyme SpoT. It has been reported that (p)ppGpp is involved in the biofilm formation and multidrug resistance of various bacteria. In this study, we found that SpoT also plays an important role in H. pylori biofilm formation and multidrug resistance. Therefore, it was necessary to carry out some further studies regarding its regulatory mechanism. Considering that efflux pumps are of great importance in the biofilm formation and multidrug resistance of bacteria, we tried to determine whether efflux pumps controlled by SpoT participate in these activities. We found that Hp1174 (glucose/galactose transporter [gluP]), an efflux pump of the major facilitator superfamily (MFS), is highly expressed in biofilm-forming and multidrug-resistant (MDR) H. pylori strains and is upregulated by SpoT. Through further research, we determined that gluP is involved in H. pylori biofilm formation and multidrug resistance. Furthermore, the average expression level of gluP in the clinical MDR strains (C-MDR) was considerably higher than that in the clinical drug-sensitive strains (C-DSS). Taken together, our results revealed a novel molecular mechanism of H. pylori resistance to multidrug exposure.
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Li S, Su Z, Zhang C, Xu Z, Chang X, Zhu J, Xiao R, Li L, Zhou R. Identification of drug target candidates of the swine pathogen Actinobacillus pleuropneumoniae by construction of protein-protein interaction network. Genes Genomics 2018; 40:847-856. [PMID: 30047117 DOI: 10.1007/s13258-018-0691-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/12/2018] [Indexed: 01/31/2023]
Abstract
Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae has led to severe economic losses in the pig industry worldwide. A. pleuropneumoniae displays various levels of antimicrobial resistance, leading to the dire need to identify new drug targets. Protein-protein interaction (PPI) network can aid the identification of drug targets by discovering essential proteins during the life of bacteria. The aim of this study is to identify drug target candidates of A. pleuropneumoniae from essential proteins in PPI network. The homologous protein mapping method (HPM) was utilized to construct A. pleuropneumoniae PPI network. Afterwards, the subnetwork centered with H-NS was selected to verify the PPI network using bacterial two-hybrid assays. Drug target candidates were identified from the hub proteins by analyzing the topology of the network using interaction degree and homologous comparison with the pig proteome. An A. pleuropneumoniae PPI network containing 2737 non-redundant interaction pairs among 533 proteins was constructed. These proteins were distributed in 21 COG functional categories and 28 KEGG metabolic pathways. The A. pleuropneumoniae PPI network was scale free and the similar topological tendencies were found when compared with other bacteria PPI network. Furthermore, 56.3% of the H-NS subnetwork interactions were validated. 57 highly connected proteins (hub proteins) were identified from the A. pleuropneumoniae PPI network. Finally, 9 potential drug targets were identified from the hub proteins, with no homologs in swine. This study provides drug target candidates, which are promising for further investigations to explore lead compounds against A. pleuropneumoniae.
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Affiliation(s)
- Siqi Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China
| | - Zhipeng Su
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China
| | - Chengjun Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China
| | - Zhuofei Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China.,Cooperative Innovation Center of Sustainable Pig Production, Wuhan, 430070, China
| | - Xiaoping Chang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China
| | - Jiawen Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China.,Institute of Animal Science, Chengdu Academy of Agriculture and Forestry Sciences, Chengdu, 611130, China
| | - Ran Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China
| | - Lu Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China. .,Cooperative Innovation Center of Sustainable Pig Production, Wuhan, 430070, China.
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan, 430070, China. .,Cooperative Innovation Center of Sustainable Pig Production, Wuhan, 430070, China.
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15
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Actinobacillus pleuropneumoniae biofilms: Role in pathogenicity and potential impact for vaccination development. Anim Health Res Rev 2017; 19:17-30. [DOI: 10.1017/s146625231700010x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AbstractActinobacillus pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurellaceae. It is the causative agent of porcine pleuropneumonia, a highly contagious respiratory disease that is responsible for major economic losses in the global pork industry. The disease may present itself as a chronic or an acute infection characterized by severe pathology, including hemorrhage, fibrinous and necrotic lung lesions, and, in the worst cases, rapid death. A. pleuropneumoniae is transmitted via aerosol route, direct contact with infected pigs, and by the farm environment. Many virulence factors associated with this bacterium are well characterized. However, much less is known about the role of biofilm, a sessile mode of growth that may have a critical impact on A. pleuropneumoniae pathogenicity. Here we review the current knowledge on A. pleuropneumoniae biofilm, factors associated with biofilm formation and dispersion, and the impact of biofilm on the pathogenesis A. pleuropneumoniae. We also provide an overview of current vaccination strategies against A. pleuropneumoniae and consider the possible role of biofilms vaccines for controlling the disease.
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16
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Liu H, Xiao Y, Nie H, Huang Q, Chen W. Influence of (p)ppGpp on biofilm regulation in Pseudomonas putida KT2440. Microbiol Res 2017; 204:1-8. [PMID: 28870288 DOI: 10.1016/j.micres.2017.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 12/21/2022]
Abstract
The global regulatory molecule (p)ppGpp is synthesized under limited nutrition conditions and involves in many cellular processes in bacteria. (p)ppGpp has been reported to affect biofilm formation in several bacterial species. Here, we found that deletion of (p)ppGpp synthase genes of Pseudomonas putida KT2440 led to enhanced biofilm formation in polystyrene microtitre plates. Besides, the pellicle of this mutant formed at the air-liquid interface lost the robust structure and became frail. The biofilm formation and its structure are mainly determined by exopolysaccharides (EPSs) and adhesins. Transcriptional analysis of four EPS operons designated as pea, peb, alg and bcs and two adhesin genes nominated as lapA and lapF showed that the deletion of (p)ppGpp synthase genes increased the expression of peb, bcs and lapA but repressed the expression of pea and lapF. Furthermore, expression of the regulation factor FleQ was significantly augmented in (p)ppGpp-synthase mutants while the expression of sigma factor RpoS was reduced. Since FleQ and RpoS play important roles in regulating expression of EPS and adhesin genes, (p)ppGpp may mediate the synthesis of biofilm matrix via influencing these regulators to control the biofilm formation and pellicle structure.
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Affiliation(s)
- Huizhong Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yujie Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hailing Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
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17
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Xu X, Yu H, Zhang D, Xiong J, Qiu J, Xin R, He X, Sheng H, Cai W, Jiang L, Zhang K, Hu X. Role of ppGpp in Pseudomonas aeruginosa acute pulmonary infection and virulence regulation. Microbiol Res 2016; 192:84-95. [PMID: 27664726 DOI: 10.1016/j.micres.2016.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 11/28/2022]
Abstract
During infection, bacteria might generate adaptive responses to facilitate their survival and colonization in the host environment. The alarmone guanosine 5'-triphosphate-3'-diphosphate (ppGpp), the levels of which are regulated by the RelA and SpoT enzymes, plays a critical role in mediating bacterial adaptive responses and virulence. However, the mechanism by which ppGpp regulates virulence-associated traits in Pseudomonas aeruginosa is poorly understood. To investigate the regulatory role of ppGpp, the ppGpp-deficient strain ΔRS (relA and spoT gene double mutant) and the complemented strain ΔRS(++) (complemented with relA and spoT genes) were constructed. Herein, we reported that the ΔRS strain showed decreased cytotoxicity towards A549 human alveolar adenocarcinoma cell lines and led to reduced mortality, lung edema and inflammatory cell infiltration in a mouse model of acute pneumonia compared to wild-type PAO1 and the complemented strain ΔRS(++). Subsequent analyses demonstrated that the ΔRS strain displayed reduced T3SS expression, decreased levels of elastase activity, pyocyanin, pyoverdin and alginate, and inhibited swarming and biofilm formation compared to PAO1 and the complemented strain ΔRS(++). In addition, the results demonstrate that ppGpp-mediated regulation of T3SS, virulence factor production, and swarming occurs in a quinolone quorum-sensing system-dependent manner. Taken together, these results suggest that ppGpp is required for virulence regulation in P. aeruginosa, providing new clues for the development of interference strategies against bacterial infection.
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Affiliation(s)
- Xiaohui Xu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Hua Yu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Di Zhang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Junzhi Xiong
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jing Qiu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Rong Xin
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xiaomei He
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Halei Sheng
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Wenqiang Cai
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Lu Jiang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Kebin Zhang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
| | - Xiaomei Hu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.
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