1
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Senevirathne A, Hewawaduge C, Lee JH. Assessment of environmental safety and protective efficacy of O-antigen deficient DIVA capable Salmonella Enteritidis against chicken salmonellosis. Poult Sci 2024; 103:103354. [PMID: 38154449 PMCID: PMC10788308 DOI: 10.1016/j.psj.2023.103354] [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: 08/25/2023] [Revised: 10/12/2023] [Accepted: 12/01/2023] [Indexed: 12/30/2023] Open
Abstract
In this study, we incorporated deletion of the O-antigen ligase gene to an attenuated Salmonella Enteritidis (SE) strain, JOL919 (SE PS; Δlon ΔcpxR), using the Lambda-Red recombination method and evaluated the safety and immunological aspects of the novel genotype, JOL2381 (SE VS: Δlon, ΔcpxR, ΔrfaL). Assessment of fecal shedding and organ persistence following administration via oral and IM routes revealed that the SE VS was safer than its parent strain, SE PS. Immunological assays confirmed that immunization via the oral route with SE PS was superior to the SE VS. However, chickens immunized with SE PS and SE VS strains via the IM route showed higher humoral and cell-mediated immune responses. Compared to PBS control, the IM route of immunization with SE VS resulted in a higher IgY antibody titer and expansion of CD4+ and CD8+ T-cell populations, which resulted in the clearance of Salmonella from the liver and splenic tissues. Furthermore, deletion of the O-antigen ligase gene caused lower production of LPS-specific antibodies in the host, promoting DIVA functionality and making it a plausible candidate for field utilization. Due to significant protection, high attenuation, and environmental safety concerns, the present SE VS strain is an ideal choice to prevent chicken salmonellosis and ensure public health.
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Affiliation(s)
- Amal Senevirathne
- College of Veterinary Medicine, Jeonbuk National University, 54596 Iksan, Republic of Korea
| | - Chamith Hewawaduge
- College of Veterinary Medicine, Jeonbuk National University, 54596 Iksan, Republic of Korea
| | - John Hwa Lee
- College of Veterinary Medicine, Jeonbuk National University, 54596 Iksan, Republic of Korea.
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2
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Krajnc M, Fei C, Košmrlj A, Kalin M, Stopar D. Mechanical constraints to unbound expansion of B. subtilis on semi-solid surfaces. Microbiol Spectr 2024; 12:e0274023. [PMID: 38047692 PMCID: PMC10783106 DOI: 10.1128/spectrum.02740-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/13/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE How bacterial cells colonize new territory is a problem of fundamental microbiological and biophysical interest and is key to the emergence of several phenomena of biological, ecological, and medical relevance. Here, we demonstrate how bacteria stuck in a colony of finite size can resume exploration of new territory by aquaplaning and how they fine tune biofilm viscoelasticity to surface material properties that allows them differential mobility. We show how changing local interfacial forces and colony viscosity results in a plethora of bacterial morphologies on surfaces with different physical and mechanical properties.
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Affiliation(s)
- Mojca Krajnc
- Biotechnical Faculty, Department of Microbiology, University of Ljubljana, Ljubljana, Slovenia
| | - Chenyi Fei
- Lewis-Sigler Institute for Integrative Genomics, Carl C. Icahn Laboratory, Princeton University, Princeton, New Jersey, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA
- Princeton Materials Institute, Princeton University, Princeton, New Jersey, USA
| | - Mitjan Kalin
- Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - David Stopar
- Biotechnical Faculty, Department of Microbiology, University of Ljubljana, Ljubljana, Slovenia
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3
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Bhattacharyya S, Bhattarai N, Pfannenstiel DM, Wilkins B, Singh A, Harshey RM. A heritable iron memory enables decision-making in Escherichia coli. Proc Natl Acad Sci U S A 2023; 120:e2309082120. [PMID: 37988472 PMCID: PMC10691332 DOI: 10.1073/pnas.2309082120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/12/2023] [Indexed: 11/23/2023] Open
Abstract
The importance of memory in bacterial decision-making is relatively unexplored. We show here that a prior experience of swarming is remembered when Escherichia coli encounters a new surface, improving its future swarming efficiency. We conducted >10,000 single-cell swarm assays to discover that cells store memory in the form of cellular iron levels. This "iron" memory preexists in planktonic cells, but the act of swarming reinforces it. A cell with low iron initiates swarming early and is a better swarmer, while the opposite is true for a cell with high iron. The swarming potential of a mother cell, which tracks with its iron memory, is passed down to its fourth-generation daughter cells. This memory is naturally lost by the seventh generation, but artificially manipulating iron levels allows it to persist much longer. A mathematical model with a time-delay component faithfully recreates the observed dynamic interconversions between different swarming potentials. We demonstrate that cellular iron levels also track with biofilm formation and antibiotic tolerance, suggesting that iron memory may impact other physiologies.
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Affiliation(s)
- Souvik Bhattacharyya
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX78712
- LaMontagne Center for Infectious Diseases, University of Texas at Austin, Austin, TX78712
| | - Nabin Bhattarai
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX78712
- LaMontagne Center for Infectious Diseases, University of Texas at Austin, Austin, TX78712
| | - Dylan M. Pfannenstiel
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX78712
- LaMontagne Center for Infectious Diseases, University of Texas at Austin, Austin, TX78712
| | - Brady Wilkins
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX78712
- LaMontagne Center for Infectious Diseases, University of Texas at Austin, Austin, TX78712
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE19716
| | - Rasika M. Harshey
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX78712
- LaMontagne Center for Infectious Diseases, University of Texas at Austin, Austin, TX78712
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4
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Mi Y, He Y, Mi J, Huang Y, Fan H, Song L, An X, Xu S, Li M, Tong Y. Genetic and Phenotypic Analysis of Phage-Resistant Mutant Fitness Triggered by Phage-Host Interactions. Int J Mol Sci 2023; 24:15594. [PMID: 37958578 PMCID: PMC10648725 DOI: 10.3390/ijms242115594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
The emergence of phage-resistant bacterial strains is one of the biggest challenges for phage therapy. However, the emerging phage-resistant bacteria are often accompanied by adaptive trade-offs, which supports a therapeutic strategy called "phage steering". The key to phage steering is to guide the bacterial population toward an evolutionary direction that is favorable for treatment. Thus, it is important to systematically investigate the impacts of phages targeting different bacterial receptors on the fitness of the bacterial population. Herein, we employed 20 different phages to impose strong evolutionary pressure on the host Pseudomonas aeruginosa PAO1 and examined the genetic and phenotypic responses of their phage-resistant mutants. Among these strains with impaired adsorptions, four types of mutations associated with bacterial receptors were identified, namely, lipopolysaccharides (LPSs), type IV pili (T4Ps), outer membrane proteins (OMPs), and exopolysaccharides (EPSs). PAO1, responding to LPS- and EPS-dependent phage infections, mostly showed significant growth impairment and virulence attenuation. Most mutants with T4P-related mutations exhibited a significant decrease in motility and biofilm formation ability, while the mutants with OMP-related mutations required the lowest fitness cost out of the bacterial populations. Apart from fitness costs, PAO1 strains might lose their resistance to antibiotics when counteracting with phages, such as the presence of large-fragment mutants in this study, which may inspire the usage of phage-antibiotic combination strategies. This work provides methods that leverage the merits of phage resistance relative to obtaining therapeutically beneficial outcomes with respect to phage-steering strategies.
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Affiliation(s)
- Yanze Mi
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Yile He
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Jinhui Mi
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Yunfei Huang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Huahao Fan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Lihua Song
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Xiaoping An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Shan Xu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Mengzhe Li
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; (Y.M.); (Y.H.); (J.M.); (Y.H.); (H.F.); (L.S.); (X.A.); (S.X.)
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), Beijing University of Chemical Technology, Beijing 100029, China
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5
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Bru JL, Kasallis SJ, Zhuo Q, Høyland-Kroghsbo NM, Siryaporn A. Swarming of P. aeruginosa: Through the lens of biophysics. BIOPHYSICS REVIEWS 2023; 4:031305. [PMID: 37781002 PMCID: PMC10540860 DOI: 10.1063/5.0128140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 08/29/2023] [Indexed: 10/03/2023]
Abstract
Swarming is a collective flagella-dependent movement of bacteria across a surface that is observed across many species of bacteria. Due to the prevalence and diversity of this motility modality, multiple models of swarming have been proposed, but a consensus on a general mechanism for swarming is still lacking. Here, we focus on swarming by Pseudomonas aeruginosa due to the abundance of experimental data and multiple models for this species, including interpretations that are rooted in biology and biophysics. In this review, we address three outstanding questions about P. aeruginosa swarming: what drives the outward expansion of a swarm, what causes the formation of dendritic patterns (tendrils), and what are the roles of flagella? We review models that propose biologically active mechanisms including surfactant sensing as well as fluid mechanics-based models that consider swarms as thin liquid films. Finally, we reconcile recent observations of P. aeruginosa swarms with early definitions of swarming. This analysis suggests that mechanisms associated with sliding motility have a critical role in P. aeruginosa swarm formation.
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Affiliation(s)
- Jean-Louis Bru
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California 92697, USA
| | - Summer J. Kasallis
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
| | - Quantum Zhuo
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
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6
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Chan DK, Dykema K, Fatima M, Harvey H, Qaderi I, Burrows LL. Nutrient Limitation Sensitizes Pseudomonas aeruginosa to Vancomycin. ACS Infect Dis 2023; 9:1408-1423. [PMID: 37279282 PMCID: PMC10353551 DOI: 10.1021/acsinfecdis.3c00167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Indexed: 06/08/2023]
Abstract
Traditional antibacterial screens rely on growing bacteria in nutrient-replete conditions which are not representative of the natural environment or sites of infection. Instead, screening in more physiologically relevant conditions may reveal novel activity for existing antibiotics. Here, we screened a panel of antibiotics reported to lack activity against the opportunistic Gram-negative bacterium, Pseudomonas aeruginosa, under low-nutrient and low-iron conditions, and discovered that the glycopeptide vancomycin inhibited the growth of P. aeruginosa at low micromolar concentrations through its canonical mechanism of action, disruption of peptidoglycan crosslinking. Spontaneous vancomycin-resistant mutants underwent activating mutations in the sensor kinase of the two-component CpxSR system, which induced cross-resistance to almost all classes of β-lactams, including the siderophore antibiotic cefiderocol. Other mutations that conferred vancomycin resistance mapped to WapR, an α-1,3-rhamnosyltransferase involved in lipopolysaccharide core biosynthesis. A WapR P164T mutant had a modified LPS profile compared to wild type that was accompanied by increased susceptibility to select bacteriophages. We conclude that screening in nutrient-limited conditions can reveal novel activity for existing antibiotics and lead to discovery of new and impactful resistance mechanisms.
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Affiliation(s)
- Derek
C. K. Chan
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Katherine Dykema
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Mahrukh Fatima
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Hanjeong Harvey
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Ikram Qaderi
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Lori L. Burrows
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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7
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Sheng Q, Liu A, Yang P, Chen Z, Wang P, Sun H, Li C, McMinn A, Chen Y, Zhang Y, Su H, Chen X, Zhang Y. The FilZ Protein Contains a Single PilZ Domain and Facilitates the Swarming Motility of Pseudoalteromonas sp. SM9913. Microorganisms 2023; 11:1566. [PMID: 37375068 DOI: 10.3390/microorganisms11061566] [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: 04/09/2023] [Revised: 06/03/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Swarming regulation is complicated in flagellated bacteria, especially those possessing dual flagellar systems. It remains unclear whether and how the movement of the constitutive polar flagellum is regulated during swarming motility of these bacteria. Here, we report the downregulation of polar flagellar motility by the c-di-GMP effector FilZ in the marine sedimentary bacterium Pseudoalteromonas sp. SM9913. Strain SM9913 possesses two flagellar systems, and filZ is located in the lateral flagellar gene cluster. The function of FilZ is negatively controlled by intracellular c-di-GMP. Swarming in strain SM9913 consists of three periods. Deletion and overexpression of filZ revealed that, during the period when strain SM9913 expands quickly, FilZ facilitates swarming. In vitro pull-down and bacterial two-hybrid assays suggested that, in the absence of c-di-GMP, FilZ interacts with the CheW homolog A2230, which may be involved in the chemotactic signal transduction pathway to the polar flagellar motor protein FliMp, to interfere with polar flagellar motility. When bound to c-di-GMP, FilZ loses its ability to interact with A2230. Bioinformatic investigation indicated that filZ-like genes are present in many bacteria with dual flagellar systems. Our findings demonstrate a novel mode of regulation of bacterial swarming motility.
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Affiliation(s)
- Qi Sheng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Ang Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Peiling Yang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Zhuowei Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Peng Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Haining Sun
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Chunyang Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Andrew McMinn
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7005, Australia
| | - Yin Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Yuzhong Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Hainan Su
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xiulan Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Yuqiang Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
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8
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Bhattacharyya S, Bhattarai N, Pfannenstiel DM, Wilkins B, Singh A, Harshey RM. Iron Memory in E. coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541523. [PMID: 37609133 PMCID: PMC10441380 DOI: 10.1101/2023.05.19.541523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The importance of memory in bacterial decision-making is relatively unexplored. We show here that a prior experience of swarming is remembered when E. coli encounters a new surface, improving its future swarming efficiency. We conducted >10,000 single-cell swarm assays to discover that cells store memory in the form of cellular iron levels. This memory pre-exists in planktonic cells, but the act of swarming reinforces it. A cell with low iron initiates swarming early and is a better swarmer, while the opposite is true for a cell with high iron. The swarming potential of a mother cell, whether low or high, is passed down to its fourth-generation daughter cells. This memory is naturally lost by the seventh generation, but artificially manipulating iron levels allows it to persist much longer. A mathematical model with a time-delay component faithfully recreates the observed dynamic interconversions between different swarming potentials. We also demonstrate that iron memory can integrate multiple stimuli, impacting other bacterial behaviors such as biofilm formation and antibiotic tolerance.
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Affiliation(s)
- Souvik Bhattacharyya
- Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, University of Texas at Austin; Austin, TX 78712
| | - Nabin Bhattarai
- Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, University of Texas at Austin; Austin, TX 78712
| | - Dylan M. Pfannenstiel
- Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, University of Texas at Austin; Austin, TX 78712
| | - Brady Wilkins
- Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, University of Texas at Austin; Austin, TX 78712
| | - Abhyudai Singh
- Electrical & Computer Engineering, University of Delaware, Newark, DE 19716
| | - Rasika M. Harshey
- Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, University of Texas at Austin; Austin, TX 78712
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9
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Clarke OE, Pelling H, Bennett V, Matsumoto T, Gregory GE, Nzakizwanayo J, Slate AJ, Preston A, Laabei M, Bock LJ, Wand ME, Ikebukuro K, Gebhard S, Sutton JM, Jones BV. Lipopolysaccharide structure modulates cationic biocide susceptibility and crystalline biofilm formation in Proteus mirabilis. Front Microbiol 2023; 14:1150625. [PMID: 37089543 PMCID: PMC10113676 DOI: 10.3389/fmicb.2023.1150625] [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: 01/24/2023] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Chlorhexidine (CHD) is a cationic biocide used ubiquitously in healthcare settings. Proteus mirabilis, an important pathogen of the catheterized urinary tract, and isolates of this species are often described as "resistant" to CHD-containing products used for catheter infection control. To identify the mechanisms underlying reduced CHD susceptibility in P. mirabilis, we subjected the CHD tolerant clinical isolate RS47 to random transposon mutagenesis and screened for mutants with reduced CHD minimum inhibitory concentrations (MICs). One mutant recovered from these screens (designated RS47-2) exhibited ~ 8-fold reduction in CHD MIC. Complete genome sequencing of RS47-2 showed a single mini-Tn5 insert in the waaC gene involved in lipopolysaccharide (LPS) inner core biosynthesis. Phenotypic screening of RS47-2 revealed a significant increase in cell surface hydrophobicity and serum susceptibility compared to the wildtype, and confirmed defects in LPS production congruent with waaC inactivation. Disruption of waaC was also associated with increased susceptibility to a range of other cationic biocides but did not affect susceptibility to antibiotics tested. Complementation studies showed that repression of smvA efflux activity in RS47-2 further increased susceptibility to CHD and other cationic biocides, reducing CHD MICs to values comparable with the most CHD susceptible isolates characterized. The formation of crystalline biofilms and blockage of urethral catheters was also significantly attenuated in RS47-2. Taken together, these data show that aspects of LPS structure and upregulation of the smvA efflux system function in synergy to modulate susceptibility to CHD and other cationic biocides, and that LPS structure is also an important factor in P. mirabilis crystalline biofilm formation.
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Affiliation(s)
- O. E. Clarke
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - H. Pelling
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - V. Bennett
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - T. Matsumoto
- Department of Biotechnology and Life Sciences, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - G. E. Gregory
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - J. Nzakizwanayo
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - A. J. Slate
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - A. Preston
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - M. Laabei
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - L. J. Bock
- United Kingdom Health Security Agency, Salisbury, United Kingdom
| | - M. E. Wand
- United Kingdom Health Security Agency, Salisbury, United Kingdom
| | - K. Ikebukuro
- Department of Biotechnology and Life Sciences, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - S. Gebhard
- Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - J. M. Sutton
- United Kingdom Health Security Agency, Salisbury, United Kingdom
| | - B. V. Jones
- Department of Life Sciences, University of Bath, Bath, United Kingdom
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10
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Bacterial Motility and Its Role in Skin and Wound Infections. Int J Mol Sci 2023; 24:ijms24021707. [PMID: 36675220 PMCID: PMC9864740 DOI: 10.3390/ijms24021707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/06/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Skin and wound infections are serious medical problems, and the diversity of bacteria makes such infections difficult to treat. Bacteria possess many virulence factors, among which motility plays a key role in skin infections. This feature allows for movement over the skin surface and relocation into the wound. The aim of this paper is to review the type of bacterial movement and to indicate the underlying mechanisms than can serve as a target for developing or modifying antibacterial therapies applied in wound infection treatment. Five types of bacterial movement are distinguished: appendage-dependent (swimming, swarming, and twitching) and appendage-independent (gliding and sliding). All of them allow bacteria to relocate and aid bacteria during infection. Swimming motility allows bacteria to spread from 'persister cells' in biofilm microcolonies and colonise other tissues. Twitching motility enables bacteria to press through the tissues during infection, whereas sliding motility allows cocci (defined as non-motile) to migrate over surfaces. Bacteria during swarming display greater resistance to antimicrobials. Molecular motors generating the focal adhesion complexes in the bacterial cell leaflet generate a 'wave', which pushes bacterial cells lacking appendages, thereby enabling movement. Here, we present the five main types of bacterial motility, their molecular mechanisms, and examples of bacteria that utilise them. Bacterial migration mechanisms can be considered not only as a virulence factor but also as a target for antibacterial therapy.
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11
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Partridge JD, Harshey RM. Swarming Motility Assays in Salmonella. Methods Mol Biol 2023; 2646:147-158. [PMID: 36842113 PMCID: PMC10942719 DOI: 10.1007/978-1-0716-3060-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Salmonella enterica has six subspecies, of which the subspecies enterica is the most important for human health. The dispersal and infectivity of this species are dependent upon flagella-driven motility. Two kinds of flagella-mediated movements have been described-swimming individually in bulk liquid and swarming collectively over a surface substrate. During swarming, the bacteria acquire a distinct physiology, the most significant consequence of which is acquisition of adaptive resistance to antibiotics. Described here are protocols to cultivate, verify, and study swimming and swarming motility in S. enterica, and an additional "border-crossing" assay, where cells "primed" to swarm are presented with an environmental challenge such as antibiotics to assess their propensity to handle the challenge.
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Affiliation(s)
- Jonathan D Partridge
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
| | - Rasika M Harshey
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
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12
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Hwang YJ, Jo J, Kim E, Yoon H, Hong H, Kim MS, Myung H. Motility increase of adherent invasive Escherichia coli (AIEC) induced by a sub-inhibitory concentration of recombinant endolysin LysPA90. Front Microbiol 2022; 13:1093670. [PMID: 36619993 PMCID: PMC9814724 DOI: 10.3389/fmicb.2022.1093670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Endolysins are bacteriophage enzymes required for the eruption of phages from inside host bacteria via the degradation of the peptidoglycan cell wall. Recombinant endolysins are increasingly being seen as potential antibacterial candidates, with a number currently undergoing clinical trials. Bacteriophage PBPA90 infecting Pseudomonas aeruginosa harbors a gene encoding an endolysin, lysPA90. Herein, recombinant LysPA90 demonstrated an intrinsic antibacterial activity against Escherichia coli in vitro. It was observed that a sub-inhibitory concentration of the recombinant protein induced the upregulation of genes related to flagella biosynthesis in a commensal E. coli strain. Increases in the number of bacterial flagella, and in motility, were experimentally substantiated. The treatment caused membrane stress, leading to the upregulation of genes rpoE, rpoH, dnaK, dnaJ, and flhC, which are upstream regulators of flagella biosynthesis. When adherent invasive Escherichia coli (AIEC) strains were treated with subinhibitory concentrations of the endolysin, bacterial adhesion and invasion into intestinal epithelial Caco-2 cells was seen to visibly increase under microscopic examination. Bacterial counting further corroborated this adhesion and invasion of AIEC strains into Caco-2 cells, with a resultant slight decrease in the viability of Caco-2 cells then being observed. Additionally, genes related to flagella expression were also upregulated in the AIEC strains. Finally, the enhanced expression of the proinflammatory cytokine genes TNF-α, IL-6, IL-8, and MCP1 in Caco-2 cells was noted after the increased invasion of the AIEC strains. While novel treatments involving endolysins offer great promise, these results highlight the need for the further exploration of possible unanticipated and unintended effects.
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Affiliation(s)
- Yoon Jung Hwang
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yong-In, Gyung-Gi Do, South Korea
- LyseNTech Co. Ltd., Seongnam, Gyung-Gi Do, South Korea
| | - Jaehak Jo
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yong-In, Gyung-Gi Do, South Korea
| | - Eunsuk Kim
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyung-Gi Do, South Korea
| | - Hyunjin Yoon
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyung-Gi Do, South Korea
| | - Hyewon Hong
- LyseNTech Co. Ltd., Seongnam, Gyung-Gi Do, South Korea
| | - Min Soo Kim
- LyseNTech Co. Ltd., Seongnam, Gyung-Gi Do, South Korea
| | - Heejoon Myung
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yong-In, Gyung-Gi Do, South Korea
- LyseNTech Co. Ltd., Seongnam, Gyung-Gi Do, South Korea
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13
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Multiple immunodominant O-epitopes co-expression in live attenuated Salmonella serovars induce cross-protective immune responses against S. Paratyphi A, S. Typhimurium and S. Enteritidis. PLoS Negl Trop Dis 2022; 16:e0010866. [PMID: 36228043 PMCID: PMC9595534 DOI: 10.1371/journal.pntd.0010866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 10/25/2022] [Accepted: 10/04/2022] [Indexed: 11/06/2022] Open
Abstract
Salmonella enterica subsp. enterica (S. enterica) is a significant public health concern and is estimated to cause more than 300,000 deaths annually. Nowadays, the vaccines available for human Salmonellosis prevention are all targeting just one serovar, i.e., S. Typhi, leaving a huge potential risk of Salmonella disease epidemiology change. In this study, we explored the strategy of multiple immunodominant O-epitopes co-expression in S. enterica serovars and evaluated their immunogenicity to induce cross-immune responses and cross-protections against S. Paratyphi A, S. Typhimurium and S. Enteritidis. We found that nucleotide sugar precursors CDP-Abe and CDP-Par (or CDP-Tyv) could be utilized by S. enterica serovars simultaneously, exhibiting O2&O4 (or O4&O9) double immunodominant O-serotypes without obvious growth defects. More importantly, a triple immunodominant O2&O4&O9 O-serotypes could be achieved in S. Typhimurium by improving the substrate pool of CDP-Par, glycosyltransferase WbaV and flippase Wzx via a dual-plasmid overexpressing system. Through immunization in a murine model, we found that double or triple O-serotypes live attenuated vaccine candidates could induce significantly higher heterologous serovar-specific antibodies than their wild-type parent strain. Meanwhile, the bacterial agglutination, serum bactericidal assays and protection efficacy experiments had all shown that these elicited serum antibodies are cross-reactive and cross-protective. Our work highlights the potential of developing a new type of live attenuated Salmonella vaccines against S. Paratyphi A, S. Typhimurium and S. Enteritidis simultaneously.
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The CRISPR-Cas System Differentially Regulates Surface-Attached and Pellicle Biofilm in Salmonella enterica Serovar Typhimurium. Microbiol Spectr 2022; 10:e0020222. [PMID: 35678575 PMCID: PMC9241790 DOI: 10.1128/spectrum.00202-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The CRISPR-Cas mediated regulation of biofilm by Salmonella enterica serovar Typhimurium was investigated by deleting CRISPR-Cas components ΔcrisprI, ΔcrisprII, ΔΔcrisprI crisprII, and Δcas op. We determined that the system positively regulates surface biofilm while inhibiting pellicle biofilm formation. Results of real-time PCR suggest that the flagellar (fliC, flgK) and curli (csgA) genes were repressed in knockout strains, causing reduced surface biofilm. The mutants displayed altered pellicle biofilm architecture. They exhibited bacterial multilayers and a denser extracellular matrix with enhanced cellulose and less curli, ergo weaker pellicles than those of the wild type. The cellulose secretion was more in the knockout strains due to the upregulation of bcsC, which is necessary for cellulose export. We hypothesized that the secreted cellulose quickly integrates into the pellicle, leading to enhanced pellicular cellulose in the knockout strains. We determined that crp is upregulated in the knockout strains, thereby inhibiting the expression of csgD and, hence, also of csgA and bcsA. The conflicting upregulation of bcsC, the last gene of the bcsABZC operon, could be caused by independent regulation by the CRISPR-Cas system owing to a partial match between the CRISPR spacers and bcsC gene. The cAMP-regulated protein (CRP)-mediated regulation of the flagellar genes in the knockout strains was probably circumvented through the regulation of yddx governing the availability of the sigma factor σ28 that further regulates class 3 flagellar genes (fliC, fljB, and flgK). Additionally, the variations in the lipopolysaccharide (LPS) profile and expression of LPS-related genes (rfaC, rfbG, and rfbI) in knockout strains could also contribute to the altered pellicle architecture. Collectively, we establish that the CRISPR-Cas system differentially regulates the formation of surface-attached and pellicle biofilm. IMPORTANCE In addition to being implicated in bacterial immunity and genome editing, the CRISPR-Cas system has recently been demonstrated to regulate endogenous gene expression and biofilm formation. While the function of individual cas genes in controlling Salmonella biofilm has been explored, the regulatory role of CRISPR arrays in biofilm is less studied. Moreover, studies have focused on the effects of the CRISPR-Cas system on surface-associated biofilms, and comprehensive studies on the impact of the system on pellicle biofilm remain an unexplored niche. We demonstrate that the CRISPR array and cas genes modulate the expression of various biofilm genes in Salmonella, whereby surface and pellicle biofilm formation is distinctively regulated.
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15
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Xu Y, Abdelhamid AG, Sabag-Daigle A, Sovic MG, Ahmer BM, Yousef AE. The Role of Egg Yolk in Modulating the Virulence of Salmonella Enterica Serovar Enteritidis. Front Cell Infect Microbiol 2022; 12:903979. [PMID: 35774398 PMCID: PMC9237210 DOI: 10.3389/fcimb.2022.903979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 04/15/2022] [Indexed: 11/13/2022] Open
Abstract
Contribution of food vehicles to pathogenicity of disease-causing microorganisms is an important but overlooked research field. The current study was initiated to reveal the relationship between virulence of Salmonella enterica serovar Enteritidis and egg yolk as a hosting medium. Mice were orally challenged with Salmonella Enteritidis cultured in egg yolk or tryptic soy broth (TSB). Additionally, mice were challenged with Salmonella Enteritidis cultured in TSB, followed by administration of sterile egg yolk, to discern the difference between pre-growth of the pathogen and its mere presence in egg yolk during infection. The pathogen’s Lethal dose 50 (LD50) was the lowest when grown in yolk (2.8×102 CFU), compared to 1.1×103 CFU in TSB, and 4.6×103 CFU in TSB followed by administration of sterile yolk. Additionally, mice that orally received Salmonella Enteritidis grown in egg yolk expressed a high death rate. These findings were supported by transcriptional analysis results. Expression of promoters of virulence-related genes (sopB and sseA) in genetically modified Salmonella Enteritidis reporter strains was significantly higher (p < 0.05) when the bacterium was grown in the yolk, compared to that grown in TSB. Sequencing of RNA (RNA-seq) revealed 204 differentially transcribed genes in Salmonella Enteritidis grown in yolk vs. TSB. Yolk-grown Salmonella Enteritidis exhibited upregulated virulence pathways, including type III secretion systems, epithelial cell invasion, and infection processes; these observations were confirmed by RT-qPCR results. The transcriptomic analysis suggested that upregulation of virulence machinery of Salmonella Enteritidis grown in egg yolk was related to increased iron uptake, biotin utilization, flagellar biosynthesis, and export of virulence proteins encoded on Salmonella pathogenicity island 1, 2, 4, and 5. These biological responses may have acted in concert to increase the virulence of Salmonella infection in mice. In conclusion, growth in egg yolk enhanced Salmonella Enteritidis virulence, indicating the significance of this food vehicle to the risk assessment of salmonellosis.
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Affiliation(s)
- Yumin Xu
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, United States
| | - Ahmed G. Abdelhamid
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, United States
- Botany and Microbiology Department, Faculty of Science, Benha University, Benha, Egypt
| | - Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Michael G. Sovic
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
| | - Brian M.M. Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Ahmed E. Yousef
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, United States
- Department of Microbiology, The Ohio State University, Columbus, OH, United States
- *Correspondence: Ahmed E. Yousef,
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16
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Adler BA, Kazakov AE, Zhong C, Liu H, Kutter E, Lui LM, Nielsen TN, Carion H, Deutschbauer AM, Mutalik VK, Arkin AP. The genetic basis of phage susceptibility, cross-resistance and host-range in Salmonella. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34910616 PMCID: PMC8744999 DOI: 10.1099/mic.0.001126] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Though bacteriophages (phages) are known to play a crucial role in bacterial fitness and virulence, our knowledge about the genetic basis of their interaction, cross-resistance and host-range is sparse. Here, we employed genome-wide screens in Salmonella enterica serovar Typhimurium to discover host determinants involved in resistance to eleven diverse lytic phages including four new phages isolated from a therapeutic phage cocktail. We uncovered 301 diverse host factors essential in phage infection, many of which are shared between multiple phages demonstrating potential cross-resistance mechanisms. We validate many of these novel findings and uncover the intricate interplay between RpoS, the virulence-associated general stress response sigma factor and RpoN, the nitrogen starvation sigma factor in phage cross-resistance. Finally, the infectivity pattern of eleven phages across a panel of 23 genome sequenced Salmonella strains indicates that additional constraints and interactions beyond the host factors uncovered here define the phage host range.
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Affiliation(s)
- Benjamin A Adler
- The UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley, California, USA.,Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Innovative Genomics Institute, University of California, Berkeley, California, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Crystal Zhong
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Hualan Liu
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | | | - Lauren M Lui
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Torben N Nielsen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Heloise Carion
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Vivek K Mutalik
- Innovative Genomics Institute, University of California, Berkeley, California, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam P Arkin
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Innovative Genomics Institute, University of California, Berkeley, California, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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17
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Surveying a Swarm: Experimental Techniques to Establish and Examine Bacterial Collective Motion. Appl Environ Microbiol 2021; 88:e0185321. [PMID: 34878816 DOI: 10.1128/aem.01853-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The survival and successful spread of many bacterial species hinges on their mode of motility. One of the most distinct of these is swarming, a collective form of motility where a dense consortium of bacteria employ flagella to propel themselves across a solid surface. Surface environments pose unique challenges, derived from higher surface friction/tension and insufficient hydration. Bacteria have adapted by deploying an array of mechanisms to overcome these challenges. Beyond allowing bacteria to colonize new terrain in the absence of bulk liquid, swarming also bestows faster speeds and enhanced antibiotic resistance to the collective. These crucial attributes contribute to the dissemination, and in some cases pathogenicity, of an array of bacteria. This mini-review highlights; 1) aspects of swarming motility that differentiates it from other methods of bacterial locomotion. 2) Facilitatory mechanisms deployed by diverse bacteria to overcome different surface challenges. 3) The (often difficult) approaches required to cultivate genuine swarmers. 4) The methods available to observe and assess the various facets of this collective motion, as well as the features exhibited by the population as a whole.
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18
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Zhou X, Liu B, Liu Y, Shi C, Fratamico PM, Zhang L, Wang D, Zhang J, Cui Y, Xu P, Shi X. Two homologous Salmonella serogroup C1-specific genes are required for flagellar motility and cell invasion. BMC Genomics 2021; 22:507. [PMID: 34225670 PMCID: PMC8259012 DOI: 10.1186/s12864-021-07759-z] [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: 03/16/2021] [Accepted: 05/26/2021] [Indexed: 11/16/2022] Open
Abstract
Background Salmonella is a major bacterial pathogen associated with a large number of outbreaks of foodborne diseases. Many highly virulent serovars that cause human illness belong to Salmonella serogroup C1, and Salmonella ser. Choleraesuis is a prominent cause of invasive infections in Asia. Comparative genomic analysis in our previous study showed that two homologous genes, SC0368 and SC0595 in Salmonella ser. Choleraesuis were unique to serogroup C1. In this study, two single-deletion mutants (Δ0368 and Δ0595) and one double-deletion mutant (Δ0368Δ0595) were constructed based on the genome. All these mutants and the wild-type strain were subjected to RNA-Seq analysis to reveal functional relationships of the two serogroup C1-specific genes. Results Data from RNA-Seq indicated that deletion of SC0368 resulted in defects in motility through repression of σ28 in flagellar regulation Class 3. Consistent with RNA-Seq data, results from transmission electron microcopy (TEM) showed that flagella were not present in △0368 and △0368△0595 mutants resulting in both swimming and swarming defects. Interestingly, the growth rates of two non-motile mutants △0368 and △0368△0595 were significantly greater than the wild-type, which may be associated with up-regulation of genes encoding cytochromes, enhancing bacterial proliferation. Moreover, the △0595 mutant was significantly more invasive in Caco-2 cells as shown by bacterial enumeration assays, and the expression of lipopolysaccharide (LPS) core synthesis-related genes (rfaB, rfaI, rfaQ, rfaY, rfaK, rfaZ) was down-regulated only in the △0368△0595 mutant. In addition, this study also speculated that these two genes might be contributing to serotype conversion for Salmonella C1 serogroup based on their apparent roles in biosynthesis of LPS and the flagella. Conclusion A combination of biological and transcriptomic (RNA-Seq) analyses has shown that the SC0368 and SC0595 genes are involved in biosynthesis of flagella and complete LPS, as well as in bacterial growth and virulence. Such information will aid to revealing the role of these specific genes in bacterial physiology and evolution within the serogroup C1. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07759-z.
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Affiliation(s)
- Xiujuan Zhou
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Bin Liu
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, 712100, Shaanxi, China
| | - Yanhong Liu
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, 19038, USA
| | - Chunlei Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Pina M Fratamico
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, 19038, USA
| | - Lida Zhang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Dapeng Wang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jianhua Zhang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yan Cui
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ping Xu
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xianming Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China.
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19
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Lau TTV, Puah SM, Tan JAMA, Puthucheary SD, Chua KH. Characterization of the relationship between polar and lateral flagellar genes in clinical Aeromonas dhakensis: phenotypic, genetic and biochemical analyses. Braz J Microbiol 2021; 52:517-529. [PMID: 33768508 DOI: 10.1007/s42770-021-00457-8] [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: 04/20/2020] [Accepted: 02/23/2021] [Indexed: 11/25/2022] Open
Abstract
Flagellar-mediated motility is a crucial virulence factor in many bacterial species. A dual flagellar system has been described in aeromonads; however, there is no flagella-related study in the emergent human pathogen Aeromonas dhakensis. Using 46 clinical A. dhakensis, phenotypic motility, genotypic characteristics (flagellar genes and sequence types), biochemical properties and their relationship were investigated in this study. All 46 strains showed swimming motility at 30 °C in 0.3% Bacto agar and carried the most prevalent 6 polar flagellar genes cheA, flgE, flgG, flgH, flgL, and flgN. On the contrary, only 18 strains (39%) demonstrated swarming motility on 0.5% Eiken agar at 30 °C and they harbored 11 lateral flagellar genes lafB, lafK, lafS, lafT, lafU, flgCL, flgGL, flgNL, fliEL, fliFL, and fliGL. No association was found between biochemical properties and motility phenotypes. Interestingly, a significant association between swarming and strains isolated from pus was observed (p = 0.0171). Three strains 187, 277, and 289 isolated from pus belonged to novel sequence types (ST522 and ST524) exhibited fast swimming and swarming profiles, and they harbored > 90% of the flagellar genes tested. Our findings provide a fundamental understanding of flagellar-mediated motility in A. dhakensis.
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Affiliation(s)
- Tien-Tien Vicky Lau
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Suat-Moi Puah
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | | | - S D Puthucheary
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kek-Heng Chua
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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20
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Wang Y, Liu G, Zhang J, Gu D, Hu M, Zhang Y, Pan Z, Geng S, Jiao X. WbaP is required for swarm motility and intramacrophage multiplication of Salmonella Enteritidis spiC mutant by glucose use ability. Microbiol Res 2020; 245:126686. [PMID: 33429286 DOI: 10.1016/j.micres.2020.126686] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/10/2020] [Accepted: 12/18/2020] [Indexed: 11/18/2022]
Abstract
Salmonella spp. can survive and replicate in macrophage cells to cause persistent infection, SpiC is a necessary T3SS effector, but its pathogenic mechanism is still not known completely. In our study, Salmonella Enteritidis spiC mutant (SEΔspiC) was found to have stronger swarming motility and intramacrophage hyperproliferation which was closely related to glucose metabolism. SEΔspiC wbaP::Tn5 mutant was screened out by transposon mutagenesis, which had weaker swarming motility and intramacrophage replication ability than SEΔspiC in the presence of glucose. Bioinformatics displayed that undecaprenyl-phosphate galactose phosphotransferase (Wbap), encoded by wbaP gene, was a key enzyme for glucose metabolism and Lipopolysaccharide(LPS) synthesis, which confirmed our outcome that Wbap was involved in intramacrophage replication ability by glucose use in addition to swarming motility based on SEΔspiC. This discovery will further promote the understanding of the interaction between wbaP gene and spiC gene and the intracellular Salmonella replication mechanism.
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Affiliation(s)
- Yaonan Wang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Guifeng Liu
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Jian Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Dan Gu
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Maozhi Hu
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yunzheng Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Zhiming Pan
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Shizhong Geng
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
| | - Xin'an Jiao
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
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Senevirathne A, Hewawaduge C, Park S, Park JY, Kirthika P, Lee JH. O-antigen-deficient, live, attenuated Salmonella typhimurium confers efficient uptake, reduced cytotoxicity, and rapid clearance in chicken macrophages and lymphoid organs and induces significantly high protective immune responses that protect chickens against Salmonella infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 111:103745. [PMID: 32470560 DOI: 10.1016/j.dci.2020.103745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/26/2020] [Accepted: 05/09/2020] [Indexed: 06/11/2023]
Abstract
In the present study, we developed an O-antigen-deficient, live, attenuated Salmonella Typhimurium (ST) strain (JOL2377) and assessed its safety, macrophage toxicity, invasion into lymphoid tissues, immunogenicity, and protection against Salmonella infection in chickens. The JOL2377 induced significantly lower cytotoxicity and higher level of cytokine response in IL-2, IL-10, IL-4, and IFN- γ than the WT strain upon macrophage uptake. It did not persist in macrophages or in chicken organs and rapidly cleared without systemic infection. None of the chicken were found to secrete Salmonella in feces into the environment exacerbating its attenuation. Interestingly JOL2377 successfully arrived in immunological hot-spots such as spleen, liver and bursa of Fabricius for an efficient antigen presentation and immune stimulation. Mucosal and parenteral immunization with JOL2377 significantly elicit antigen-specific humoral (IgY) and cell mediated responses marked by peripheral blood mononuclear cell proliferation, cytokine induction, increase in T-cell responses than non-immunized control. JOL2377 did not generate significant levels of LPS specific antibodies as compared to the WT strain due to the lack of immunogenic O-antigen component from its LPS structure. Upon virulent challenge, route dependent efficacy differences were leaving the intramuscular route is superior to the oral route on reducing splenic and liver colonization of the challenge ST. The least cytotoxicity, virulence, and superior immunogenicity of JL2377 that effectively engage both humoral and IFN- γ mediated CMI responses present an ideal scenario in host immune modulation to fight against intracellular pathogen Salmonella.
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Affiliation(s)
- Amal Senevirathne
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea
| | - Chamith Hewawaduge
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea
| | - Sungwoo Park
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea
| | - Ji-Young Park
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea
| | - Perumalraja Kirthika
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea
| | - John Hwa Lee
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea.
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22
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Rhodeland B, Hoeger K, Ursell T. Bacterial surface motility is modulated by colony-scale flow and granular jamming. J R Soc Interface 2020; 17:20200147. [PMID: 32574537 DOI: 10.1098/rsif.2020.0147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Microbes routinely face the challenge of acquiring territory and resources on wet surfaces. Cells move in large groups inside thin, surface-bound water layers, often achieving speeds of 30 µm s-1 within this environment, where viscous forces dominate over inertial forces (low Reynolds number). The canonical Gram-positive bacterium Bacillus subtilis is a model organism for the study of collective migration over surfaces with groups exhibiting motility on length-scales three orders of magnitude larger than themselves within a few doubling times. Genetic and chemical studies clearly show that the secretion of endogenous surfactants and availability of free surface water are required for this fast group motility. Here, we show that: (i) water availability is a sensitive control parameter modulating an abiotic jamming-like transition that determines whether the group remains fluidized and therefore collectively motile, (ii) groups self-organize into discrete layers as they travel, (iii) group motility does not require proliferation, rather groups are pulled from the front, and (iv) flow within expanding groups is capable of moving material from the parent colony into the expanding tip of a cellular dendrite with implications for expansion into regions of varying nutrient content. Together, these findings illuminate the physical structure of surface-motile groups and demonstrate that physical properties, like cellular packing fraction and flow, regulate motion from the scale of individual cells up to length scales of centimetres.
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Affiliation(s)
- Ben Rhodeland
- Department of Physics, University of Oregon, Eugene OR 97403, USA
| | - Kentaro Hoeger
- Department of Physics, University of Oregon, Eugene OR 97403, USA
| | - Tristan Ursell
- Department of Physics, University of Oregon, Eugene OR 97403, USA.,Institute of Molecular Biology, University of Oregon, Eugene OR 97403, USA.,Materials Science Institute, University of Oregon, Eugene OR 97403, USA
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24
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Wu Z, He R, Zhang R, Yuan J. Swarming Motility Without Flagellar Motor Switching by Reversal of Swimming Direction in E. coli. Front Microbiol 2020; 11:1042. [PMID: 32670212 PMCID: PMC7326100 DOI: 10.3389/fmicb.2020.01042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 04/27/2020] [Indexed: 01/08/2023] Open
Abstract
In a crowded environment such as a bacterial swarm, cells frequently got jammed and came to a stop, but were able to escape the traps by backing up in their moving course with a head-to-tail change (a reversal). Reversals are essential for the expansion of a bacterial swarm. Reversal for a wildtype cell usually involved polymorphic transformation of the flagellar filaments induced by directional switching of the flagellar motors. Here we discovered a new way of reversal in cells without motor switching and characterized its mechanisms. We further found that this type of reversal was not limited to swarmer cells, but also occurred for cells grown in a bulk solution. Therefore, reversal was a general way of escaping when cells got jammed in their natural complex habitats. The new way of reversal we discovered here offered a general strategy for cells to escape traps and explore their environment.
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Affiliation(s)
- Zhengyu Wu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Rui He
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Rongjing Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Junhua Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
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25
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Jayeola V, McClelland M, Porwollik S, Chu W, Farber J, Kathariou S. Identification of Novel Genes Mediating Survival of Salmonella on Low-Moisture Foods via Transposon Sequencing Analysis. Front Microbiol 2020; 11:726. [PMID: 32499760 PMCID: PMC7242855 DOI: 10.3389/fmicb.2020.00726] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/27/2020] [Indexed: 01/11/2023] Open
Abstract
Salmonella enterica is the leading foodborne pathogen associated with outbreaks involving low-moisture foods (LMFs). However, the genes involved in Salmonella's long-term survival on LMFs remain poorly characterized. In this study, in-shell pistachios were inoculated with Tn5-based mutant libraries of S. Enteritidis P125109, S. Typhimurium 14028s, and S. Newport C4.2 at approximate 108 CFU/g and stored at 25°C. Transposon sequencing analysis (Tn-seq) was then employed to determine the relative abundance of each Tn5 insertion site immediately after inoculation (T0), after drying (T1), and at 120 days (T120). In S. Enteritidis, S. Typhimurium, and S. Newport mutant libraries, the relative abundance of 51, 80, and 101 Tn5 insertion sites, respectively, was significantly lower at T1 compared to T0, while in libraries of S. Enteritidis and S. Typhimurium the relative abundance of 42 and 68 Tn5 insertion sites, respectively, was significantly lower at T120 compared to T1. Tn5 insertion sites with reduced relative abundance in this competition assay were localized in DNA repair, lipopolysaccharide biosynthesis and stringent response genes. Twelve genes among those under strong negative selection in the competition assay were selected for further study. Whole gene deletion mutants in ten of these genes, sspA, barA, uvrB, damX, rfbD, uvrY, lrhA, yifE, rbsR, and ompR, were impaired for individual survival on pistachios. The findings highlight the value of combined mutagenesis and sequencing to identify novel genes important for the survival of Salmonella in low-moisture foods.
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Affiliation(s)
- Victor Jayeola
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Weiping Chu
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Jeffrey Farber
- Department of Food Science, University of Guelph, Guelph, ON, Canada
| | - Sophia Kathariou
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, United States
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26
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Ali A, Ovais M, Cui X, Rui Y, Chen C. Safety Assessment of Nanomaterials for Antimicrobial Applications. Chem Res Toxicol 2020; 33:1082-1109. [DOI: 10.1021/acs.chemrestox.9b00519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Arbab Ali
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, P.R. China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P.R. China
| | - Muhammad Ovais
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Xuejing Cui
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P.R. China
| | - YuKui Rui
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, P.R. China
| | - Chunying Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
- GBA Research Innovation Institute for Nanotechnology, Guangdong 510700, China
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27
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Atypical Salmonella enterica Serovars in Murine and Human Macrophage Infection Models. Infect Immun 2020; 88:IAI.00353-19. [PMID: 32014897 DOI: 10.1128/iai.00353-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 01/28/2020] [Indexed: 11/20/2022] Open
Abstract
Nontyphoidal Salmonella species are globally disseminated pathogens and are the predominant cause of gastroenteritis. The pathogenesis of salmonellosis has been extensively studied using in vivo murine models and cell lines, typically challenged with Salmonella enterica serovar Typhimurium. Although S. enterica serovars Enteritidis and Typhimurium are responsible for most of the human infections reported to the Centers for Disease Control and Prevention (CDC), several other serovars also contribute to clinical cases of salmonellosis. Despite their epidemiological importance, little is known about their infection phenotypes. Here, we report the virulence characteristics and genomes of 10 atypical S. enterica serovars linked to multistate foodborne outbreaks in the United States. We show that the murine RAW 264.7 macrophage model of infection is unsuitable for inferring human-relevant differences in nontyphoidal Salmonella infections, whereas differentiated human THP-1 macrophages allowed these isolates to be further characterized in a more human-relevant context.
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28
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Kotian HS, Abdulla AZ, Hithysini KN, Harkar S, Joge S, Mishra A, Singh V, Varma MM. Active modulation of surfactant-driven flow instabilities by swarming bacteria. Phys Rev E 2020; 101:012407. [PMID: 32069638 DOI: 10.1103/physreve.101.012407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Indexed: 12/15/2022]
Abstract
Models based on surfactant-driven instabilities have been employed to describe pattern formation by swarming bacteria. However, by definition, such models cannot account for the effect of bacterial sensing and decision making. Here we present a more complete model for bacterial pattern formation which accounts for these effects by coupling active bacterial motility to the passive fluid dynamics. We experimentally identify behaviors which cannot be captured by previous models based on passive population dispersal and show that a more accurate description is provided by our model. It is seen that the coupling of bacterial motility to the fluid dynamics significantly alters the phase space of surfactant-driven pattern formation. We also show that our formalism is applicable across bacterial species.
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Affiliation(s)
- Harshitha S Kotian
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, India.,Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, India
| | - Amith Z Abdulla
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, India
| | - K N Hithysini
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Shalini Harkar
- Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, India
| | - Shubham Joge
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Ayushi Mishra
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Varsha Singh
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Manoj M Varma
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, India.,Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, India
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29
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The Role of Pseudomonas aeruginosa Lipopolysaccharide in Bacterial Pathogenesis and Physiology. Pathogens 2019; 9:pathogens9010006. [PMID: 31861540 PMCID: PMC7168646 DOI: 10.3390/pathogens9010006] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is a key molecule on the bacterial cell wall that is recognized by the host to deploy an immune defence in order to neutralize invading pathogens. However, LPS also promotes bacterial survival in a host environment by protecting the bacteria from these threats. This review explores the relationship between the different LPS glycoforms of the opportunistic pathogen Pseudomonas aeruginosa and the ability of this organism to cause persistent infections, especially in the genetic disease cystic fibrosis. We also discuss the role of LPS in facilitating biofilm formation, antibiotic resistance, and how LPS may be targeted by new antimicrobial therapies.
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30
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Hassan AA, Coutinho CP, Sá-Correia I. Burkholderia cepacia Complex Species Differ in the Frequency of Variation of the Lipopolysaccharide O-Antigen Expression During Cystic Fibrosis Chronic Respiratory Infection. Front Cell Infect Microbiol 2019; 9:273. [PMID: 31417878 PMCID: PMC6686744 DOI: 10.3389/fcimb.2019.00273] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/17/2019] [Indexed: 11/13/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) bacteria can adapt to the lung environment of cystic fibrosis (CF) patients resulting in the emergence of a very difficult to eradicate heterogeneous population leading to chronic infections associated with rapid lung function loss and increased mortality. Among the important phenotypic modifications is the variation of the lipopolysaccharide (LPS) structure at level of the O-antigen (OAg) presence, influencing adherence, colonization and the ability to evade the host defense mechanisms. The present study was performed to understand whether the loss of OAg expression during CF infection can be considered a general phenomenon in different Bcc species favoring its chronicity. In fact, it is still not clear why different Bcc species/strains differ in their ability to persist in the CF lung and pathogenic potential. The systematic two-decade-retrospective-longitudinal-screening conducted covered 357 isolates retrieved from 19 chronically infected patients receiving care at a central hospital in Lisbon. The study involved 21 Bcc strains of six/seven Bcc species/lineages, frequently or rarely isolated from CF patients worldwide. Different strains/clonal variants obtained during infection gave rise to characteristic OAg-banding patterns. The two most prevalent and feared species, B. cenocepacia and B. multivorans, showed a tendency to lose the OAg along chronic infection. B. cenocepacia recA lineage IIIA strains known to lead to particularly destructive infections exhibit the most frequent OAg loss, compared with lineage IIIB. The switch frequency increased with the duration of infection and the level of lung function deterioration. For the first time, it is shown that the rarely found B. cepacia and B. contaminans, whose representation in the cohort of patients examined is abnormally high, keep the OAg even during 10- or 15-year infections. Data from co-infections with different Bcc species reinforced these conclusions. Concerning the two other rarely found species examined, B. stabilis exhibited a stable OAg expression phenotype over the infection period while for the single clone of the more distantly related B. dolosa species, the OAg-chain was absent from the beginning of the 5.5-year infection until the patient dead. This work reinforces the relevance attributed to the OAg-expression switch suggesting marked differences in the various Bcc species.
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Affiliation(s)
- A. Amir Hassan
- iBB - Institute for Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Carla P. Coutinho
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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Cell Shape and Population Migration Are Distinct Steps of Proteus mirabilis Swarming That Are Decoupled on High-Percentage Agar. J Bacteriol 2019; 201:JB.00726-18. [PMID: 30858303 DOI: 10.1128/jb.00726-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/08/2019] [Indexed: 01/10/2023] Open
Abstract
Swarming on rigid surfaces requires movement of cells as individuals and as a group of cells. For the bacterium Proteus mirabilis, an individual cell can respond to a rigid surface by elongating and migrating over micrometer-scale distances. Cells can form groups of transiently aligned cells, and the collective population is capable of migrating over centimeter-scale distances. To address how P. mirabilis populations swarm on rigid surfaces, we asked whether cell elongation and single-cell motility are coupled to population migration. We first measured the relationship between agar concentration (a proxy for surface rigidity), single-cell phenotypes, and swarm colony phenotypes. We find that cell elongation and single-cell motility are coupled with population migration on low-percentage hard agar (1% to 2.5%) and become decoupled on high-percentage hard agar (>2.5%). Next, we evaluate how disruptions in lipopolysaccharide (LPS), specifically the O-antigen components, affect responses to hard agar. We find that LPS is not essential for elongation and motility of individual cells, as predicted, and instead functions to broaden the range of agar concentrations on which cell elongation and motility are coupled with population migration. These findings demonstrate that cell elongation and motility are coupled with population migration under a permissive range of surface conditions; increasing agar concentration is sufficient to decouple these behaviors. Since swarm colonies cover greater distances when these steps are coupled than when they are not, these findings suggest that collective interactions among P. mirabilis cells might be emerging as a colony expands outwards on rigid surfaces.IMPORTANCE How surfaces influence cell size, cell-cell interactions, and population migration for robust swarmers like P. mirabilis is not fully understood. Here, we have elucidated how cells change length along a spectrum of sizes that positively correlates with increases in agar concentration, regardless of population migration. Single-cell phenotypes can be decoupled from collective population migration simply by increasing agar concentration. A cell's lipopolysaccharides function to broaden the range of agar conditions under which cell elongation and single-cell motility remain coupled with population migration. In eukaryotes, the physical environment, such as a surface matrix, can impact cell development, shape, and migration. These findings support the idea that rigid surfaces similarly act on swarming bacteria to impact cell shape, single-cell motility, and collective population migration.
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32
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Zhao H, Liu YP, Zhang LQ. In silico and Genetic Analyses of Cyclic Lipopeptide Synthetic Gene Clusters in Pseudomonas sp. 11K1. Front Microbiol 2019; 10:544. [PMID: 30941113 PMCID: PMC6433849 DOI: 10.3389/fmicb.2019.00544] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/01/2019] [Indexed: 02/02/2023] Open
Abstract
Pseudomonas sp. 11K1, originally isolated from rhizosphere, possesses inhibitory activity against plant pathogenic fungi and bacteria. Herein, the genome of strain 11K1 was sequenced and subjected to in silico, mutational, and functional analyses. The 11K1 genome is 6,704,877 bp in length, and genome mining identified three potential cyclic lipopeptide (CLP) biosynthetic clusters, subsequently named brasmycin, braspeptin, and brasamide. Insertional and deletion mutants displayed impaired brasmycin and braspeptin production, and lost antifungal activity, but retained antibacterial activity against Xanthomonas oryzae. The structures of these two active CLPs were predicted based on adenylation (A) domains. Brasmycin is composed of nine amino acids and belongs to the syringomycin class, while braspeptin is a 22 amino acid cyclic peptide belonging to the tolaasin group. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry analysis revealed that brasmycin and braspeptin have different molecular weights compared with known syringomycin and tolaasin members, respectively. Mutation of brasmycin and braspeptin gene clusters affected both biofilm formation and colony morphology. Collectively, these results indicate that Pseudomonas sp. 11K1 produces two novel CLPs that may help bacteria compete for nutrients and niches in the environment.
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Affiliation(s)
- Hui Zhao
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing, China
| | - Yan-Ping Liu
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Li-Qun Zhang
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing, China
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33
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Zuo J, Tu C, Wang Y, Qi K, Hu J, Wang Z, Mi R, Yan huang, Chen Z, Han X. The role of the wzy gene in lipopolysaccharide biosynthesis and pathogenesis of avian pathogenic Escherichia coli. Microb Pathog 2019; 127:296-303. [DOI: 10.1016/j.micpath.2018.12.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 01/08/2023]
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34
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Be’er A, Ariel G. A statistical physics view of swarming bacteria. MOVEMENT ECOLOGY 2019; 7:9. [PMID: 30923619 PMCID: PMC6419441 DOI: 10.1186/s40462-019-0153-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/18/2019] [Indexed: 05/18/2023]
Abstract
Bacterial swarming is a collective mode of motion in which cells migrate rapidly over surfaces, forming dynamic patterns of whirls and jets. This review presents a physical point of view of swarming bacteria, with an emphasis on the statistical properties of the swarm dynamics as observed in experiments. The basic physical principles underlying the swarm and their relation to contemporary theories of collective motion and active matter are reviewed and discussed in the context of the biological properties of swarming cells. We suggest a paradigm according to which bacteria have optimized some of their physical properties as a strategy for rapid surface translocation. In other words, cells take advantage of favorable physics, enabling efficient expansion that enhances survival under harsh conditions.
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Affiliation(s)
- Avraham Be’er
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990 Midreshet Ben-Gurion, Israel
- Department of Physics, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Gil Ariel
- Department of Mathematics, Bar-Ilan University, 52000 Ramat Gan, Israel
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35
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The Role of the Motility of Methylobacterium in Bacterial Interactions in Drinking Water. WATER 2018. [DOI: 10.3390/w10101386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bacterial motility is one important factor that affects biofilm formation. In drinking water there are key bacteria in aggregation, whose biology acts to enhance the formation of biofilms. However, it is unclear whether the motility of these key bacteria is an important factor for the interactions between bacteria in drinking water, and, subsequently, in the formation of aggregates, which are precursors to biofilms. Thus, the role of the motility of one of these key bacteria, the Methylobacterium strain DSM 18358, was investigated in the interactions between bacteria in drinking water. The motility of pure Methylobacterium colonies was initially explored; if it was affected by the viscosity of substrate, the temperature, the available energy and the type of substrate. Furthermore, the role of Methylobacterium in the interactions between mixed drinking water bacteria was investigated under the mostly favourable conditions for the motility of Methylobacterium identified before. Overall, the motility of Methylobacterium was found to play a key role in the communication and interactions between bacteria in drinking water. Understanding the role of the motility of key bacteria in drinking water might be useful for the water industry as a potential tool to control the formation of biofilms in drinking water pipes.
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36
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Swarmer Cell Development of the Bacterium Proteus mirabilis Requires the Conserved Enterobacterial Common Antigen Biosynthesis Gene rffG. J Bacteriol 2018; 200:JB.00230-18. [PMID: 29967121 DOI: 10.1128/jb.00230-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 06/27/2018] [Indexed: 01/01/2023] Open
Abstract
Individual cells of the bacterium Proteus mirabilis can elongate up to 40-fold on surfaces before engaging in a cooperative surface-based motility termed swarming. How cells regulate this dramatic morphological remodeling remains an open question. In this paper, we move forward the understanding of this regulation by demonstrating that P. mirabilis requires the gene rffG for swarmer cell elongation and subsequent swarm motility. The rffG gene encodes a protein homologous to the dTDP-glucose 4,6-dehydratase protein of Escherichia coli, which contributes to enterobacterial common antigen biosynthesis. Here, we characterize the rffG gene in P. mirabilis, demonstrating that it is required for the production of large lipopolysaccharide-linked moieties necessary for wild-type cell envelope integrity. We show that the absence of the rffG gene induces several stress response pathways, including those controlled by the transcriptional regulators RpoS, CaiF, and RcsB. We further show that in rffG-deficient cells, the suppression of the Rcs phosphorelay, via loss of RcsB, is sufficient to induce cell elongation and swarm motility. However, the loss of RcsB does not rescue cell envelope integrity defects and instead results in abnormally shaped cells, including cells producing more than two poles. We conclude that an RcsB-mediated response acts to suppress the emergence of shape defects in cell envelope-compromised cells, suggesting an additional role for RcsB in maintaining cell morphology under stress conditions. We further propose that the composition of the cell envelope acts as a checkpoint before cells initiate swarmer cell elongation and motility.IMPORTANCEProteus mirabilis swarm motility has been implicated in pathogenesis. We have found that cells deploy multiple uncharacterized strategies to handle cell envelope stress beyond the Rcs phosphorelay when attempting to engage in swarm motility. While RcsB is known to directly inhibit the master transcriptional regulator for swarming, we have shown an additional role for RcsB in protecting cell morphology. These data support a growing appreciation that the Rcs phosphorelay is a multifunctional regulator of cell morphology in addition to its role in microbial stress responses. These data also strengthen the paradigm that outer membrane composition is a crucial checkpoint for modulating entry into swarm motility. Furthermore, the rffG-dependent moieties provide a novel attractive target for potential antimicrobials.
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Maigaard Hermansen GM, Boysen A, Krogh TJ, Nawrocki A, Jelsbak L, Møller-Jensen J. HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli. Front Cell Infect Microbiol 2018; 8:253. [PMID: 30131942 PMCID: PMC6090259 DOI: 10.3389/fcimb.2018.00253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/04/2018] [Indexed: 12/12/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.
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Affiliation(s)
| | - Anders Boysen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Thøger J Krogh
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Arkadiusz Nawrocki
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Lars Jelsbak
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Novel Role of VisP and the Wzz System during O-Antigen Assembly in Salmonella enterica Serovar Typhimurium Pathogenesis. Infect Immun 2018; 86:IAI.00319-18. [PMID: 29866904 DOI: 10.1128/iai.00319-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 01/18/2023] Open
Abstract
Salmonella enterica serovars are associated with diarrhea and gastroenteritis and are a helpful model for understanding host-pathogen mechanisms. Salmonella enterica serovar Typhimurium regulates the distribution of O antigen (OAg) and presents a trimodal distribution based on Wzy polymerase and the WzzST (long-chain-length OAg [L-OAg]) and WzzfepE (very-long-chain-length OAg [VL-OAg]) copolymerases; however, several mechanisms regulating this process remain unclear. Here, we report that LPS modifications modulate the infectious process and that OAg chain length determination plays an essential role during infection. An increase in VL-OAg is dependent on Wzy polymerase, which is promoted by a growth condition resembling the environment of Salmonella-containing vacuoles (SCVs). The virulence- and stress-related periplasmic protein (VisP) participates in OAg synthesis, as a ΔvisP mutant presents a semirough OAg phenotype. The ΔvisP mutant has greatly decreased motility and J774 macrophage survival in a colitis model of infection. Interestingly, the phenotype is restored after mutation of the wzzST or wzzfepE gene in a ΔvisP background. Loss of both the visP and wzzST genes promotes an imbalance in flagellin secretion. L-OAg may function as a shield against host immune systems in the beginning of an infectious process, and VL-OAg protects bacteria during SCV maturation and facilitates intramacrophage replication. Taken together, these data highlight the roles of OAg length in generating phenotypes during S Typhimurium pathogenesis and show the periplasmic protein VisP as a novel protein in the OAg biosynthesis pathway.
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Regulation of Flagellum Biosynthesis in Response to Cell Envelope Stress in Salmonella enterica Serovar Typhimurium. mBio 2018; 9:mBio.00736-17. [PMID: 29717015 PMCID: PMC5930307 DOI: 10.1128/mbio.00736-17] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Flagellum-driven motility of Salmonella enterica serovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population of Salmonella, resulting in flagellated and nonflagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4C2 with respect to proteolytic degradation. Information concerning the environmental cues controlling expression of rflP and thus about the bistable flagellar biosynthesis remains ambiguous. Here, we demonstrated that RflP responds to cell envelope stress and alterations of outer membrane integrity. Lipopolysaccharide (LPS) truncation mutants of Salmonella Typhimurium exhibited increasing motility defects due to downregulation of flagellar gene expression. Transposon mutagenesis and genetic profiling revealed that σ24 (RpoE) and Rcs phosphorelay-dependent cell envelope stress response systems sense modifications of the lipopolysaccaride, low pH, and activity of the complement system. This subsequently results in activation of RflP expression and degradation of FlhD4C2 via ClpXP. We speculate that the presence of diverse hostile environments inside the host might result in cell envelope damage and would thus trigger the repression of resource-costly and immunogenic flagellum biosynthesis via activation of the cell envelope stress response. Pathogenic bacteria such as Salmonella Typhimurium sense and adapt to a multitude of changing and stressful environments during host infection. At the initial stage of gastrointestinal colonization, Salmonella uses flagellum-mediated motility to reach preferred sites of infection. However, the flagellum also constitutes a prime target for the host’s immune response. Accordingly, the pathogen needs to determine the spatiotemporal stage of infection and control flagellar biosynthesis in a robust manner. We found that Salmonella uses signals from cell envelope stress-sensing systems to turn off production of flagella. We speculate that downregulation of flagellum synthesis after cell envelope damage in hostile environments aids survival of Salmonella during late stages of infection and provides a means to escape recognition by the immune system.
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40
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Penttinen R, Hoikkala V, Sundberg LR. Gliding Motility and Expression of Motility-Related Genes in Spreading and Non-spreading Colonies of Flavobacterium columnare. Front Microbiol 2018; 9:525. [PMID: 29632520 PMCID: PMC5879114 DOI: 10.3389/fmicb.2018.00525] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 03/08/2018] [Indexed: 11/13/2022] Open
Abstract
Gliding motility facilitates the movement of bacteria along surfaces in many Bacteroidetes species and results in spreading colonies. The adhesins required for the gliding are secreted through a gliding motility-associated protein secretion system, known as the type IX secretion system (T9SS). The fish pathogen Flavobacterium columnare produces spreading (rhizoid [Rz], soft [S]) and non-spreading (rough [R]) colony types, of which only the spreading Rz type is virulent. In this study, we explored the spreading behavior of these colony types by microscopic imaging and measured the expression of genes associated with gliding motility and T9SS (gldG, gldH, gldL, sprA, sprB, sprE, sprF, sprT, and porV) under high and low resource levels by using RT-qPCR (reverse transcription quantitative PCR). The spreading colony types responded to the low resource level with increased colony size. The non-spreading colony type, as well as the cells growing under high nutrient level expressed only moderate cell movements. Yet, a low nutrient level provoked more active gliding motility in individual cells and increased spreading by cooperative gliding. The gene expression survey demonstrated an increased expression level of sprA (a core component of T9SS) and sprF (needed for adhesin secretion) under low nutrient conditions. Surprisingly, the expression of gliding motility genes was not consistently associated with more active spreading behavior. Furthermore, no genetic differences were found between spreading and non-spreading colony types in the studied genes associated with gliding motility. Our study demonstrates that environmental nutrient level is an important regulator of both gliding motility and the expression of some of the associated genes. These results may help to understand the connections between nutrient concentration, gliding motility, and virulence of F. columnare.
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Affiliation(s)
- Reetta Penttinen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Ville Hoikkala
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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41
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Mattingly AE, Weaver AA, Dimkovikj A, Shrout JD. Assessing Travel Conditions: Environmental and Host Influences On Bacterial Surface Motility. J Bacteriol 2018; 200:e00014-18. [PMID: 29555698 PMCID: PMC5952383 DOI: 10.1128/jb.00014-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The degree to which surface motile bacteria explore their surroundings is influenced by aspects of their local environment. Accordingly, regulation of surface motility is controlled by numerous chemical, physical, and biological stimuli. Discernment of such regulation due to these multiple cues is a formidable challenge. Additionally inherent ambiguity and variability from the assays used to assess surface motility can be an obstacle to clear delineation of regulated surface motility behavior. Numerous studies have reported single environmental determinants of microbial motility and lifestyle behavior but the translation of these data to understand surface motility and bacterial colonization of human host or environmental surfaces is unclear. Here, we describe the current state of the field and our understanding of exogenous factors that influence bacterial surface motility.
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Affiliation(s)
- Anne E. Mattingly
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Abigail A. Weaver
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Aleksandar Dimkovikj
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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42
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Segev-Zarko LA, Kapach G, Josten M, Klug YA, Sahl HG, Shai Y. Deficient Lipid A Remodeling by the arnB Gene Promotes Biofilm Formation in Antimicrobial Peptide Susceptible Pseudomonas aeruginosa. Biochemistry 2018. [PMID: 29518324 DOI: 10.1021/acs.biochem.8b00149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multidrug resistant bacteria possess various mechanisms that can sense environmental stresses such as antibiotics and antimicrobial peptides and rapidly respond to defend themselves. Two known defense strategies are biofilm formation and lipopolysaccharide (LPS) modification. Though LPS modifications are observed in biofilm-embedded bacteria, their effect on biofilm formation is unknown. Using biochemical and biophysical methods coupled with confocal microscopy, atomic force microscopy, and transmission electron microscopy, we show that biofilm formation is promoted in a Pseudomonas aeruginosa PAO1 strain with a loss of function mutation in the arnB gene. This loss of function prevents the addition of the positively charged sugar 4-amino-4-deoxy-l-arabinose to lipid A of LPS under restrictive magnesium conditions. The data reveal that the arnB mutant, which is susceptible to antimicrobial peptides, forms a biofilm that is more robust than that of the wild type. This is in line with the observations that the arnB mutant exhibits outer surface properties such as hydrophobicity and net negative charge that promote the formation of biofilms. Moreover, when grown under Mg2+ limitation, both the wild type and the arnB mutant exhibited a reduction in the level of membrane-bound polysaccharides. The data suggest that the loss of polysaccharides exposes the membrane and alters its biophysical properties, which in turn leads to more biofilm formation. In summary, we show for the first time that blocking a specific lipid A modification promotes biofilm formation, suggesting a trade-off between LPS remodeling and resistance mechanisms of biofilm formation.
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Affiliation(s)
- Li-Av Segev-Zarko
- Department of Biomolecular Sciences , The Weizmann Institute of Science , Rehovot , Israel
| | - Gal Kapach
- Department of Biomolecular Sciences , The Weizmann Institute of Science , Rehovot , Israel
| | - Michaele Josten
- Institute of Medical Microbiology, Immunology and Parasitology , University of Bonn , Bonn , Germany
| | - Yoel Alexander Klug
- Department of Biomolecular Sciences , The Weizmann Institute of Science , Rehovot , Israel
| | - Hans-Georg Sahl
- Institute of Medical Microbiology, Immunology and Parasitology , University of Bonn , Bonn , Germany
| | - Yechiel Shai
- Department of Biomolecular Sciences , The Weizmann Institute of Science , Rehovot , Israel
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43
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Medrano-Félix JA, Chaidez C, Mena KD, Soto-Galindo MDS, Castro-Del Campo N. Characterization of biofilm formation by Salmonella enterica at the air-liquid interface in aquatic environments. ENVIRONMENTAL MONITORING AND ASSESSMENT 2018; 190:221. [PMID: 29546664 DOI: 10.1007/s10661-018-6585-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain. Salmonella Oranienburg and Saintpaul from feces were moderately hydrophobic and motile, while S. Saintpaul from water and the control strain S. Typhimurium showed high hydrophobicity, which helped them form more resistant biofilms than S. Oranienburg. Under stressful conditions, all strains experienced difficulties in forming biofilms. Salmonella Saintpaul and Typhimurium expressed the red dry and rough (RDAR) morphotype and were able to form biofilm at air-liquid interface, contrarily to Oranienburg that showed incomplete rough morphology. This study contributes to the knowledge of biofilm formation as a survival strategy for Salmonella in aquatic environments.
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Affiliation(s)
- José Andrés Medrano-Félix
- CONACYT-Centro de Investigación en Alimentación y Desarrollo A.C., Coordinación Regional Culiacán, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria, Culiacán, Sinaloa, Mexico
| | - Cristóbal Chaidez
- Centro de Investigación en Alimentación y Desarrollo A.C., Coordinación Regional Culiacán, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria, Carretera a Eldorado km. 5.5 Campo El Diez, 80110, Culiacán, Sinaloa, Mexico
| | - Kristina D Mena
- Health Science Center at Houston, The University of Texas, Houston, TX, USA
| | - María Del Socorro Soto-Galindo
- Centro de Investigación en Alimentación y Desarrollo A.C., Coordinación Regional Culiacán, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria, Carretera a Eldorado km. 5.5 Campo El Diez, 80110, Culiacán, Sinaloa, Mexico
| | - Nohelia Castro-Del Campo
- Centro de Investigación en Alimentación y Desarrollo A.C., Coordinación Regional Culiacán, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria, Carretera a Eldorado km. 5.5 Campo El Diez, 80110, Culiacán, Sinaloa, Mexico.
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44
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Abstract
Naturally occurring photonic structures are responsible for the bright and vivid coloration in a large variety of living organisms. Despite efforts to understand their biological functions, development, and complex optical response, little is known of the underlying genes involved in the development of these nanostructures in any domain of life. Here, we used Flavobacterium colonies as a model system to demonstrate that genes responsible for gliding motility, cell shape, the stringent response, and tRNA modification contribute to the optical appearance of the colony. By structural and optical analysis, we obtained a detailed correlation of how genetic modifications alter structural color in bacterial colonies. Understanding of genotype and phenotype relations in this system opens the way to genetic engineering of on-demand living optical materials, for use as paints and living sensors.
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45
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Ren Y, Wang C, Chen Z, Allan E, van der Mei HC, Busscher HJ. Emergent heterogeneous microenvironments in biofilms: substratum surface heterogeneity and bacterial adhesion force-sensing. FEMS Microbiol Rev 2018; 42:259-272. [DOI: 10.1093/femsre/fuy001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022] Open
Affiliation(s)
- Yijin Ren
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Can Wang
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
- School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, Wuhan, China
| | - Zhi Chen
- School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, Wuhan, China
| | - Elaine Allan
- UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Henk J Busscher
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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46
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Li P, Liu Q, Luo H, Liang K, Yi J, Luo Y, Hu Y, Han Y, Kong Q. O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections. Front Immunol 2017; 8:1647. [PMID: 29255460 PMCID: PMC5722840 DOI: 10.3389/fimmu.2017.01647] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/10/2017] [Indexed: 12/16/2022] Open
Abstract
Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S. Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S. Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion–insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S. Typhimurium vaccine S738 (Δcrp Δcya) to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD50) of wild-type S. Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S. Typhimurium, S. Enteritidis, and S. Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S. Typhimurium vaccines against NTS infections.
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Affiliation(s)
- Pei Li
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Qing Liu
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Hongyan Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Kang Liang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Jie Yi
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ying Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yunlong Hu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yue Han
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, United States.,Department of Infectious Diseases and Pathology, University of Florida, Gainesville, FL, United States
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47
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Li T, Noel KD. Synthesis of N-acetyl-d-quinovosamine in Rhizobium etli CE3 is completed after its 4-keto-precursor is linked to a carrier lipid. MICROBIOLOGY-SGM 2017; 163:1890-1901. [PMID: 29165235 DOI: 10.1099/mic.0.000576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial O-antigens are synthesized on lipid carriers before being transferred to lipopolysaccharide core structures. Rhizobium etli CE3 lipopolysaccharide is a model for understanding O-antigen biological function. CE3 O-antigen structure and genetics are known. However, proposed enzymology for CE3 O-antigen synthesis has been examined very little in vitro, and even the sugar added to begin the synthesis is uncertain. A model based on mutagenesis studies predicts that 2-acetamido-2,6-dideoxy-d-glucose (QuiNAc) is the first O-antigen sugar and that genes wreV, wreQ and wreU direct QuiNAc synthesis and O-antigen initiation. Previously, synthesis of UDP-QuiNAc was shown to occur in vitro with a WreV orthologue (4,6-hexose dehydratase) and WreQ (4-reductase), but the WreQ catalysis in this conventional deoxyhexose-synthesis pathway was very slow. This seeming deficiency was explained in the present study after WreU transferase activity was examined in vitro. Results fit the prediction that WreU transfers sugar-1-phosphate to bactoprenyl phosphate (BpP) to initiate O-antigen synthesis. Interestingly, WreU demonstrated much higher activity using the product of the WreV catalysis [UDP-4-keto-6-deoxy-GlcNAc (UDP-KdgNAc)] as the sugar-phosphate donor than using UDP-QuiNAc. Furthermore, the WreQ catalysis with WreU-generated BpPP-KdgNAc as the substrate was orders of magnitude faster than with UDP-KdgNAc. The inferred product BpPP-QuiNAc reacted as an acceptor substrate in an in vitro assay for addition of the second O-antigen sugar, mannose. These results imply a novel pathway for 6-deoxyhexose synthesis that may be commonly utilized by bacteria when QuiNAc is the first sugar of a polysaccharide or oligosaccharide repeat unit: UDP-GlcNAc → UDP-KdgNAc → BpPP-KdgNAc → BpPP-QuiNAc.
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Affiliation(s)
- Tiezheng Li
- Present address: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.,Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - K Dale Noel
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
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48
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Zhao X, Dai Q, Jia R, Zhu D, Liu M, Wang M, Chen S, Sun K, Yang Q, Wu Y, Cheng A. Two Novel Salmonella Bivalent Vaccines Confer Dual Protection against Two Salmonella Serovars in Mice. Front Cell Infect Microbiol 2017; 7:391. [PMID: 28929089 PMCID: PMC5591321 DOI: 10.3389/fcimb.2017.00391] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 08/22/2017] [Indexed: 12/12/2022] Open
Abstract
Non-typhoidal Salmonella includes thousands of serovars that are leading causes of foodborne diarrheal illness worldwide. In this study, we constructed three bivalent vaccines for preventing both Salmonella Typhimurium and Salmonella Newport infections by using the aspartate semialdehyde dehydrogenase (Asd)-based balanced-lethal vector-host system. The constructed Asd+ plasmid pCZ11 carrying a subset of the Salmonella Newport O-antigen gene cluster including the wzx-wbaR-wbaL-wbaQ-wzy-wbaW-wbaZ genes was introduced into three Salmonella Typhimurium mutants: SLT19 (Δasd) with a smooth LPS phenotype, SLT20 (Δasd ΔrfbN) with a rough LPS phenotype, and SLT22 (Δasd ΔrfbN ΔpagL::T araC PBADrfbN) with a smooth LPS phenotype when grown with arabinose. Immunoblotting demonstrated that SLT19 harboring pCZ11 [termed SLT19 (pCZ11)] co-expressed the homologous and heterologous O-antigens; SLT20 (pCZ11) exclusively expressed the heterologous O-antigen; and when arabinose was available, SLT22 (pCZ11) expressed both types of O-antigens, while in the absence of arabinose, SLT22 (pCZ11) expressed only the heterologous O-antigen. Exclusive expression of the heterologous O-antigen in Salmonella Typhimurium decreased the swimming ability of the bacterium and its susceptibility to polymyxin B. Next, the crp gene was deleted from the three recombinant strains for attenuation purposes, generating the three bivalent vaccine strains SLT25 (pCZ11), SLT26 (pCZ11), and SLT27 (pCZ11), respectively. Groups of BALB/c mice (12 mice/group) were orally immunized with 109 CFU of each vaccine strain twice at an interval of 4 weeks. Compared with a mock immunization, immunization with all three vaccine strains induced significant serum IgG responses against both Salmonella Typhimurium and Salmonella Newport LPS. The bacterial loads in the mouse tissues were significantly lower in the three vaccine-strain-immunized groups than in the mock group after either Salmonella Typhimurium or Salmonella Newport lethal challenge. All of the mice in the three vaccine-immunized groups survived the lethal Salmonella Typhimurium challenge. In contrast, SLT26 (pCZ11) and SLT27 (pCZ11) conferred full protection against lethal Salmonella Newport challenge, but SLT25 (pCZ11) provided only 50% heterologous protection. Thus, we developed two novel Salmonella bivalent vaccines, SLT26 (pCZ11) and SLT27 (pCZ11), suggesting that the delivery of a heterologous O-antigen in attenuated Salmonella strains is a prospective approach for developing Salmonella vaccines with broad serovar coverage.
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Affiliation(s)
- Xinxin Zhao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Qinlong Dai
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Renyong Jia
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Dekang Zhu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Mafeng Liu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Mingshu Wang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Shun Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Kunfeng Sun
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Qiao Yang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Ying Wu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Anchun Cheng
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
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49
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Huang C, Liu Q, Luo Y, Li P, Liu Q, Kong Q. Regulated delayed synthesis of lipopolysaccharide and enterobacterial common antigen of Salmonella Typhimurium enhances immunogenicity and cross-protective efficacy against heterologous Salmonella challenge. Vaccine 2017; 34:4285-92. [PMID: 27423383 DOI: 10.1016/j.vaccine.2016.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/03/2016] [Accepted: 07/06/2016] [Indexed: 10/21/2022]
Abstract
Lipopolysaccharide (LPS) O-antigen and enterobacterial common antigen (ECA) are two major polysaccharide structures on the surface of Salmonella enterica serovar Typhimurium. Previous studies have demonstrated that regulated truncation of LPS enhances the cross-reaction against conserved outer membrane proteins (OMPs) from enteric bacteria. We speculate that the regulation of both O-antigen and ECA may enhance the induction of immune responses against conserved OMPs from enteric bacteria. In this work we targeted rfbB and rffG genes which encode dTDP-glucose 4,6-dehydratases and share the same function in regulating O-antigen and ECA synthesis. We constructed a mutant, S496 (ΔrfbB6 ΔrffG7 ΔpagL73::TT araC PBADrfbB-3), in which rfbB gene expression was dependent on exogenously supplied arabinose during in vitro growth and achieved the simultaneous tight regulation of both LPS and ECA synthesis, as demonstrated by the LPS profile and Western blotting using antisera against LPS and ECA. When administered orally, S. Typhimurium S496 was completely attenuated for virulence but still retained the capacity to colonize and disseminate in mice. In addition, we found that oral immunization with S496 resulted in increased immune responses against OMPs from enteric bacteria and enhanced survival compared with immunization with S492 possessing ΔrfbB6 ΔrffG8 mutations when challenged with lethal doses of Salmonella Choleraesuis or Salmonella Enteritidis. These results indicate that S. Typhimurium arabinose-regulated rfbB strain S496 is a good vaccine candidate, conferring cross-protection against lethal challenge with heterologous Salmonella.
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Affiliation(s)
- Chun Huang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qing Liu
- Department of Bioengineering, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Yali Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Pei Li
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qiong Liu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
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50
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Surface Sensing for Paenibacillus sp. NAIST15-1 Flagellar Gene Expression on Solid Medium. Appl Environ Microbiol 2017; 83:AEM.00585-17. [PMID: 28550060 DOI: 10.1128/aem.00585-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/19/2017] [Indexed: 11/20/2022] Open
Abstract
A rhizosphere Gram-positive bacterial isolate, Paenibacillus sp. NAIST15-1, exhibits intriguing motility behavior on hard agar medium. Paenibacillus sp. shows increased transcription of flagellar genes and hyperflagellation when transferred from liquid to solid medium. Hyperflagellated cells form wandering colonies that are capable of moving around on the surface of medium containing ≥1.5% agar. Transposon mutagenesis was used to identify genes critical for motility. In addition to flagellar genes, this mutagenesis identified five nonflagellar structural genes that were important for motility. Of these, the disruption of degSU, wsfP, or PBN151_4312 resulted in a complete loss of flagellin synthesis. Analysis of flagellar gene promoter activity showed that each mutation severely reduced flagellar gene transcription in a different manner. Flagellar gene transcription was induced in liquid medium by the addition of a viscous agent, Ficoll, or by disruption of flagellar stator genes, indicating that flagellar gene transcription was induced in response to restriction of flagellar rotation. Overexpression of DegSU bypassed the requirement of flagellar rotation restriction for induction of flagellar genes. These results indicate that physical restriction of flagellar rotation by physical contact with the surface of solid medium induces flagellar gene transcription through the activation of DegSU. Further analysis revealed that the same mechanism was conserved in Bacillus subtilis These results demonstrate that flagella act as mechanosensors to control flagellar transcription in Gram-positive bacteria.IMPORTANCE Many bacteria exist on living or nonliving surfaces in nature. Bacteria express distinct behaviors, such as surface motility and biofilm formation, to adapt to surfaces. However, it remains largely unknown how bacteria sense the surfaces on which they sit and how they induce the genes needed for growth on a surface. Swarming motility is flagellum-dependent motility on a surface. The Gram-positive bacterium Paenibacillus sp. exhibits strong swarming motility ability and is capable of moving on 1.5% agar medium. In this study, we showed that the two-component system DegSU was responsible for inducing flagellar genes in response to heavy loads on flagellar rotation in Paenibacillus sp. The same mechanism was conserved in a related species, B. subtilis, even though these two bacteria exhibit very different motility behaviors. This study shows that flagellum serves as a sensor for surface contact to induce flagellar gene transcription in these bacteria.
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