101
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Photodynamic control of bacterial motility by means of azobenzene molecules. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2021.100074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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102
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Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2021; 88:101028. [PMID: 34813978 DOI: 10.1016/j.preteyeres.2021.101028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
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Affiliation(s)
- Rohan Bir Singh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Leiden University Medical Center, 2333, ZA Leiden, the Netherlands
| | - Sujata Das
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Bhubaneshwar, India
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Michael E Zegans
- Department of Ophthalmology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Regis P Kowalski
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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103
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Lopes GV, Ramires T, Kleinubing NR, Scheik LK, Fiorentini ÂM, Padilha da Silva W. Virulence factors of foodborne pathogen Campylobacterjejuni. Microb Pathog 2021; 161:105265. [PMID: 34699927 DOI: 10.1016/j.micpath.2021.105265] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/27/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022]
Abstract
Campylobacter jejuni is a highly frequent cause of gastrointestinal foodborne disease in humans throughout the world. Disease outcomes vary from mild to severe diarrhea, and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Transmission to humans usually occurs via the consumption of a range of foods, especially those associated with the consumption of raw or undercooked poultry meat, unpasteurized milk, and water-based environmental sources. When associated to food or water ingestion, the C. jejuni enters the human host intestine via the oral route and colonizes the distal ileum and colon. When it adheres and colonizes the intestinal cell surfaces, the C. jejuni is expected to express several putative virulence factors, which cause damage to the intestine either directly, by cell invasion and/or production of toxin(s), or indirectly, by triggering inflammatory responses. This review article highlights various C. jejuni characteristics - such as motility and chemotaxis - that contribute to the biological fitness of the pathogen, as well as factors involved in human host cell adhesion and invasion, and their potential role in the development of the disease. We have analyzed and critically discussed nearly 180 scientific articles covering the latest improvements in the field.
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Affiliation(s)
- Graciela Volz Lopes
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Tassiana Ramires
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Natalie Rauber Kleinubing
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Letícia Klein Scheik
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Ângela Maria Fiorentini
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil
| | - Wladimir Padilha da Silva
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia Eliseu Maciel, Universidade Federal de Pelotas (UFPel), Caixa Postal 354, 96160-000, Pelotas, RS, Brazil.
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104
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Novel Amiloride Derivatives That Inhibit Bacterial Motility across Multiple Strains and Stator Types. J Bacteriol 2021; 203:e0036721. [PMID: 34516280 DOI: 10.1128/jb.00367-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial flagellar motor (BFM) is a protein complex that confers motility to cells and contributes to survival and virulence. The BFM consists of stators that are ion-selective membrane protein complexes and a rotor that directly connects to a large filament, acting as a propeller. The stator complexes couple ion transit across the membrane to torque that drives rotation of the motor. The most common ion gradients that drive BFM rotation are protons (H+) and sodium ions (Na+). The sodium-powered stators, like those in the PomA/PomB stator complex of Vibrio spp., can be inhibited by sodium channel inhibitors, in particular, by phenamil, a potent and widely used inhibitor. However, relatively few new sodium motility inhibitors have been described since the discovery of phenamil. In this study, we characterized two possible motility inhibitors, HM2-16F and BB2-50F, from a small library of previously reported amiloride derivatives. We used three approaches: effect on rotation of tethered cells, effect on free-swimming bacteria, and effect on rotation of marker beads. We showed that both HM2-16F and BB2-50F stopped rotation of tethered cells driven by Na+ motors comparable to phenamil at matching concentrations and could also stop rotation of tethered cells driven by H+ motors. Bead measurements in the presence and absence of stators confirmed that the compounds did not inhibit rotation via direct association with the stator, in contrast to the established mode of action of phenamil. Overall, HM2-16F and BB2-50F stopped swimming in both Na+ and H+ stator types and in pathogenic and nonpathogenic strains. IMPORTANCE Here, we characterized two novel amiloride derivatives in the search for antimicrobial compounds that target bacterial motility. These compounds were shown to inhibit flagellar motility at 10 μM across multiple strains: from nonpathogenic Escherichia coli with flagellar rotation driven by proton or chimeric sodium-powered stators, to proton-powered pathogenic E. coli (enterohemorrhagic E. coli or uropathogenic E. coli [EHEC or UPEC, respectively]), and finally, sodium-powered Vibrio alginolyticus. Broad antimotility compounds such as these are important tools in our efforts to control virulence of pathogens in health and agricultural settings.
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105
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Liu Y, Lehnert T, Gijs MAM. Effect of inoculum size and antibiotics on bacterial traveling bands in a thin microchannel defined by optical adhesive. MICROSYSTEMS & NANOENGINEERING 2021; 7:86. [PMID: 34745645 PMCID: PMC8536744 DOI: 10.1038/s41378-021-00309-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Phenotypic diversity in bacterial flagella-induced motility leads to complex collective swimming patterns, appearing as traveling bands with transient locally enhanced cell densities. Traveling bands are known to be a bacterial chemotactic response to self-generated nutrient gradients during growth in resource-limited microenvironments. In this work, we studied different parameters of Escherichia coli (E. coli) collective migration, in particular the quantity of bacteria introduced initially in a microfluidic chip (inoculum size) and their exposure to antibiotics (ampicillin, ciprofloxacin, and gentamicin). We developed a hybrid polymer-glass chip with an intermediate optical adhesive layer featuring the microfluidic channel, enabling high-content imaging of the migration dynamics in a single bacterial layer, i.e., bacteria are confined in a quasi-2D space that is fully observable with a high-magnification microscope objective. On-chip bacterial motility and traveling band analysis was performed based on individual bacterial trajectories by means of custom-developed algorithms. Quantifications of swimming speed, tumble bias and effective diffusion properties allowed the assessment of phenotypic heterogeneity, resulting in variations in transient cell density distributions and swimming performance. We found that incubation of isogeneic E. coli with different inoculum sizes eventually generated different swimming phenotype distributions. Interestingly, incubation with antimicrobials promoted bacterial chemotaxis in specific cases, despite growth inhibition. Moreover, E. coli filamentation in the presence of antibiotics was assessed, and the impact on motility was evaluated. We propose that the observation of traveling bands can be explored as an alternative for fast antimicrobial susceptibility testing.
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Affiliation(s)
- Yang Liu
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Thomas Lehnert
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Martin A. M. Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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106
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Cheng X, Xu J, Smith G, Nirmalakhandan N, Zhang Y. Metagenomic profiling of antibiotic resistance and virulence removal: Activated sludge vs. algal wastewater treatment system. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 295:113129. [PMID: 34182338 PMCID: PMC8338905 DOI: 10.1016/j.jenvman.2021.113129] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 05/13/2021] [Accepted: 06/18/2021] [Indexed: 05/19/2023]
Abstract
Conventional activated sludge-based (CAS) wastewater treatment plants are known to be a source of antibiotic resistance genes (ARGs) and virulence genes (VGs). As an alternative, a single-step mixotrophic algal wastewater treatment (A-WWT) system is proposed here to effectively reduce ARGs and VGs in the final effluent while meeting all the discharge standards. In this study, we applied the metagenomic profiling approach to compare the A-WWT system against the CAS system in terms of removal efficacy of ARG and VGs. A total of 111 ARG and 93 VG subtypes belonging to 10 antibiotic resistant classes and 19 virulence classes were detected in this study. Although the CAS system reduced the relative abundance of most classes of ARGs (7 of 10) and VGs (11 of 19), 3 ARG classes and 7 VG classes had increased abundances. On the other hand, the A-WWT system reduced the relative abundance of all classes of ARGs and VGs, and effectively eliminated most subtypes of ARGs and VGs. In the CAS system, the bacterial genera carrying ARGs and VGs was expanded, and the diversity index was increased greatly, suggesting the occurrence of horizontal gene transfer (HGT). In contrast, the A-WWT system narrowed down the potential host range and decreased their diversity substantially. Results of this study highlight the potential risk of ARGs and VGs in CAS system and demonstrate the feasibility of the algal-based system in removing ARGs and VGs.
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Affiliation(s)
- Xiaoxiao Cheng
- Civil Engineering Department, New Mexico State University, Las Cruces, NM, 88003, USA
| | - Jiannong Xu
- Biology Department, New Mexico State University, Las Cruces, NM, 88003, USA
| | - Geoffrey Smith
- Biology Department, New Mexico State University, Las Cruces, NM, 88003, USA
| | | | - Yanyan Zhang
- Civil Engineering Department, New Mexico State University, Las Cruces, NM, 88003, USA.
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107
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Can only one physiological trait determinate the adverse effect of green fluorescent protein (GFP) incorporation on Vibrio virulence? Appl Microbiol Biotechnol 2021; 105:7899-7912. [PMID: 34559285 DOI: 10.1007/s00253-021-11556-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
Green fluorescent protein (GFP) has been used extensively for in situ animal studies that follow up bacterial infection under epifluorescence microscopy. It is assumed that GFP is acting as a "neutral" protein with no influence on the bacterial physiology. To verify this hypothesis, the virulence of Vibrio splendidus ME9, Vibrio anguillarum NB10, and their respective GFP-tagged strains ME9-GFP and NB10-GFP (transconjugants) was compared in vitro and tested in vivo towards blue mussel (Mytilus edulis) larvae. Results showed that the incorporation of GFP negatively impacted the growth and swimming motility of NB10 in vitro. Correspondingly, the mRNA levels of genes involved in bacterial swimming motility (flaA, flaE, and cheR) were significantly down-regulated in NB10-GFP. As for the strain ME9 on the other hand, GFP incorporation only had a negative effect on swimming motility. However, both the strains NB10-GFP and ME9-GFP showed almost the same virulence as their respective parental strain towards mussel larvae in vivo. Overall, the data presented here demonstrated that incorporation of GFP may cause modifications in cell physiology and highlight the importance of preliminary physiological tests to minimize the negative influence of GFP tagging when it is used to monitor the target localization. The study also supports the idea that the virulence of Vibrio species is determined by complex regulatory networks. Notwithstanding the change of a single physiological trait, especially growth or swimming motility, the GFP-tagged Vibrio strain can thus still be considered usable in studies mainly focusing on the virulence of the strain. KEY POINTS: • The effect of GFP incorporation on physiological trait of Vibrio strains. • The virulence in vibrios could be multifactorial. • The stable virulence of Vibrio strains after GFP incorporation.
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108
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Cascarano MC, Stavrakidis-Zachou O, Mladineo I, Thompson KD, Papandroulakis N, Katharios P. Mediterranean Aquaculture in a Changing Climate: Temperature Effects on Pathogens and Diseases of Three Farmed Fish Species. Pathogens 2021; 10:1205. [PMID: 34578236 PMCID: PMC8466566 DOI: 10.3390/pathogens10091205] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 02/07/2023] Open
Abstract
Climate change is expected to have a drastic effect on aquaculture worldwide. As we move forward with the agenda to increase and diversify aquaculture production, rising temperatures will have a progressively relevant impact on fish farming, linked to a multitude of issues associated with fish welfare. Temperature affects the physiology of both fish and pathogens, and has the potential to lead to significant increases in disease outbreaks within aquaculture systems, resulting in severe financial impacts. Significant shifts in future temperature regimes are projected for the Mediterranean Sea. We therefore aim to review and discuss the existing knowledge relating to disease outbreaks in the context of climate change in Mediterranean finfish aquaculture. The objective is to describe the effects of temperature on the physiology of both fish and pathogens, and moreover to list and discuss the principal diseases of the three main fish species farmed in the Mediterranean, namely gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), and meagre (Argyrosomus regius). We will attempt to link the pathology of each disease to a specific temperature range, while discussing potential future disease threats associated with the available climate change trends for the Mediterranean Sea.
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Affiliation(s)
- Maria Chiara Cascarano
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece; (M.C.C.); (O.S.-Z.); (N.P.)
- Department of Biology, University of Crete, 71003 Heraklion, Greece
| | - Orestis Stavrakidis-Zachou
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece; (M.C.C.); (O.S.-Z.); (N.P.)
- Department of Biology, University of Crete, 71003 Heraklion, Greece
| | - Ivona Mladineo
- Biology Center of Czech Academy of Sciences, Laboratory of Functional Helminthology, Institute of Parasitology, 370 05 Ceske Budejovice, Czech Republic;
| | - Kim D. Thompson
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK;
| | - Nikos Papandroulakis
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece; (M.C.C.); (O.S.-Z.); (N.P.)
| | - Pantelis Katharios
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece; (M.C.C.); (O.S.-Z.); (N.P.)
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109
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Corral J, Pérez-Varela M, Sánchez-Osuna M, Cortés P, Barbé J, Aranda J. Importance of twitching and surface-associated motility in the virulence of Acinetobacter baumannii. Virulence 2021; 12:2201-2213. [PMID: 34515614 PMCID: PMC8451467 DOI: 10.1080/21505594.2021.1950268] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Acinetobacter baumannii is a pathogen of increasing clinical importance worldwide, especially given its ability to readily acquire resistance determinants. Motile strains of this bacterium can move by either or both of two types of motility: (i) twitching, driven by type IV pili, and (ii) surface-associated motility, an appendage-independent form of movement. A. baumannii strain MAR002 possesses both twitching and surface-associated motility. In this study, we isolated spontaneous rifampin-resistant mutants of strain MAR002 in which point mutations in the rpoB gene were identified that resulted in an altered motility pattern. Transcriptomic analysis of mutants lacking twitching, surface-associated motility, or both led to the identification of deregulated genes within each motility phenotype, based on their level of expression and their biological function. Investigations of the corresponding knockout mutants revealed several genes involved in the motility of A. baumannii strain MAR002, including two involved in twitching (encoding a minor pilin subunit and an RND [resistance nodulation division] component), one in surface-associated motility (encoding an amino acid permease), and eight in both (encoding RND and ABC components, the energy transducer TonB, the porin OprD, the T6SS component TagF, an IclR transcriptional regulator, a PQQ-dependent sugar dehydrogenase, and a putative pectate lyase). Virulence assays showed the reduced pathogenicity of mutants with impairments in both types of motility or in surface-associated motility alone. By contrast, the virulence of twitching-affected mutants was not affected. These results shed light on the key role of surface-associated motility and the limited role of twitching in the pathogenicity of A. baumannii.
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Affiliation(s)
- Jordi Corral
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - María Pérez-Varela
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Miquel Sánchez-Osuna
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Pilar Cortés
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Jordi Barbé
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Jesús Aranda
- Departament De Genètica I Microbiologia, Facultat De Biociènces, Universitat Autònoma De Barcelona, Barcelona, Spain
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110
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Li F, Xiong XS, Yang YY, Wang JJ, Wang MM, Tang JW, Liu QH, Wang L, Gu B. Effects of NaCl Concentrations on Growth Patterns, Phenotypes Associated With Virulence, and Energy Metabolism in Escherichia coli BW25113. Front Microbiol 2021; 12:705326. [PMID: 34484145 PMCID: PMC8415458 DOI: 10.3389/fmicb.2021.705326] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022] Open
Abstract
According to the sit-and-wait hypothesis, long-term environmental survival is positively correlated with increased bacterial pathogenicity because high durability reduces the dependence of transmission on host mobility. Many indirectly transmitted bacterial pathogens, such as Mycobacterium tuberculosis and Burkhoderia pseudomallei, have high durability in the external environment and are highly virulent. It is possible that abiotic stresses may activate certain pathways or the expressions of certain genes, which might contribute to bacterial durability and virulence, synergistically. Therefore, exploring how bacterial phenotypes change in response to environmental stresses is important for understanding their potentials in host infections. In this study, we investigated the effects of different concentrations of salt (sodium chloride, NaCl), on survival ability, phenotypes associated with virulence, and energy metabolism of the lab strain Escherichia coli BW25113. In particular, we investigated how NaCl concentrations influenced growth patterns, biofilm formation, oxidative stress resistance, and motile ability. In terms of energy metabolism that is central to bacterial survival, glucose consumption, glycogen accumulation, and trehalose content were measured in order to understand their roles in dealing with the fluctuation of osmolarity. According to the results, trehalose is preferred than glycogen at high NaCl concentration. In order to dissect the molecular mechanisms of NaCl effects on trehalose metabolism, we further checked how the impairment of trehalose synthesis pathway (otsBA operon) via single-gene mutants influenced E. coli durability and virulence under salt stress. After that, we compared the transcriptomes of E. coli cultured at different NaCl concentrations, through which differentially expressed genes (DEGs) and differential pathways with statistical significance were identified, which provided molecular insights into E. coli responses to NaCl concentrations. In sum, this study explored the in vitro effects of NaCl concentrations on E. coli from a variety of aspects and aimed to facilitate our understanding of bacterial physiological changes under salt stress, which might help clarify the linkages between bacterial durability and virulence outside hosts under environmental stresses.
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Affiliation(s)
- Fen Li
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Xue-Song Xiong
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Ying-Ying Yang
- School of Life Sciences, Xuzhou Medical University, Xuzhou, China
| | - Jun-Jiao Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Meng-Meng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jia-Wei Tang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Qing-Hua Liu
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, China
| | - Liang Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China.,Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Bing Gu
- Medical Technology School of Xuzhou Medical University, Xuzhou, China.,Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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111
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Gati NS, Temme IJ, Middendorf-Bauchart B, Kehl A, Dobrindt U, Mellmann A. Comparative phenotypic characterization of hybrid Shiga toxin-producing / uropathogenic Escherichia coli, canonical uropathogenic and Shiga toxin-producing Escherichia coli. Int J Med Microbiol 2021; 311:151533. [PMID: 34425494 DOI: 10.1016/j.ijmm.2021.151533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 07/29/2021] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
Hybrid Shiga toxin (Stx)-producing Escherichia coli (STEC) and uropathogenic E. coli (UPEC) strains are phylogenetically positioned between STEC and UPEC and can cause both diarrhea and urinary tract infections (UTIs). However, their virulence properties and adaptation to different host milieu in comparison to canonical UPEC and STEC strains are unknown. We determined phenotypes of the STEC/UPEC hybrid with respect to virulence including acid resistance, motility, biofilm formation, siderophore production, and adherence to human colonic Caco-2 and bladder T24 cells and compared to phenotypes of commensal strain MG1655, UPEC strain 536, and STEC strains B2F1 and Sakai. Moreover, we assessed the adaptation of the hybrid to artificial urine medium (AUM) and simulated colonic environment medium (SCEM). Overall acid resistance at pH 2.5 was high except in strains B2F1 and hybrid 05-00787 which showed reduced and extremely low acid resistance, respectively. Motility was reduced in hybrid 05-00787 and 09-05501 but strong in the remaining hybrids. While some hybrids showed high biofilm formation in LB, overall biofilm formation in SCEM and AUM were low and non-existent, respectively. All strains tested showed siderophore activity at equilibrium. All strains except MG1655 adhered to Caco-2 cells with the hybrid having similar adherence when compared to 536 but exhibited 2 and 3 times lower adherence when compared to B2F1 and Sakai, respectively. All Stx-producing strains adhered stronger to T24 cells than strains 536 and MG1655. Overall growth in LB, SCEM and AUM was consistent within the hybrid strains, except hybrid 05-00787 which showed significantly different growth patterns. Our data suggest that the hybrid is adapted to both, the intestinal and extraintestinal milieu. Expression of phenotypes typical of intestinal and extraintestinal pathogens thereby supports its potential to cause diarrhea and UTI.
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Affiliation(s)
| | | | | | - Alexander Kehl
- University Hospital Münster, Institute of Hygiene, Münster, Germany
| | - Ulrich Dobrindt
- University Hospital Münster, Institute of Hygiene, Microbial Genome-Plasticity, Münster, Germany
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112
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Zhang S, Yang Q, Defoirdt T. Indole decreases the virulence of pathogenic vibrios belonging to the Harveyi clade. J Appl Microbiol 2021; 132:167-176. [PMID: 34297464 DOI: 10.1111/jam.15227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/28/2021] [Accepted: 07/16/2021] [Indexed: 11/29/2022]
Abstract
AIM Indole is a signaling molecule secreted by over 85 species of bacteria, including several Vibrio species, and it has been reported to affect different bacterial phenotypes such as biofilm formation, motility, and virulence. In this study, we aimed at investigating the inter-strain variability of the effect of indole in 12 different strains belonging to the Harveyi clade of vibrios. METHODS AND RESULTS Indole reduced the virulence of all strains towards gnotobiotic brine shrimp larvae. The survival rate of brine shrimp larvae challenged with vibrios pretreated with indole was increased by 1.3-fold to 1.8-fold. Additionally, indole significantly decreased the biofilm formation in all of the strains, decreased the swimming motility in eight of the strains, and decreased swarming motility in five of the strains. When cultured in the presence of exogenous indole, the mRNA level of the pirA and pirB toxin genes were down-regulated to 65% and 46%, and to 62% and 55% in the AHPND-causing strains Vibrio parahaemolyticus M0904 and Vibrio campbellii S01, respectively. CONCLUSIONS These data indicate that indole has a significant impact on the virulence of different strains belonging to the Harveyi clade of vibrios. SIGNIFICANCE AND IMPACT OF THE STUDY Our results suggest that indole signaling is a valid target for the development of novel therapeutics in order to control infections caused by Harveyi clade vibrios in aquaculture.
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Affiliation(s)
- Shanshan Zhang
- Center for Microbial Ecology and Technology (CMET), Ghent University, Gent, Belgium
| | - Qian Yang
- Center for Microbial Ecology and Technology (CMET), Ghent University, Gent, Belgium
| | - Tom Defoirdt
- Center for Microbial Ecology and Technology (CMET), Ghent University, Gent, Belgium
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113
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Reverse vaccinology approach for the identifications of potential vaccine candidates against Salmonella. Int J Med Microbiol 2021; 311:151508. [PMID: 34182206 DOI: 10.1016/j.ijmm.2021.151508] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 03/14/2021] [Accepted: 04/15/2021] [Indexed: 12/26/2022] Open
Abstract
Salmonella is a leading cause of foodborne pathogen which causes intestinal and systemic diseases across the world. Vaccination is the most effective protection against Salmonella, but the identification and design of an effective broad-spectrum vaccine is still a great challenge, because of the multi-serotypes of Salmonella. Reverse vaccinology is a new tool to discovery and design vaccine antigens combining human immunology, structural biology and computational biology with microbial genomics. In this study, reverse vaccinology, an in-silico approach was established to screen appropriate immunogen targets by calculating the immunogenicity score of 583 non-redundant outer membrane and secreted proteins of Salmonella. Herein among 100 proteins identified with top-ranked scores, 15 representative antigens were selected randomly. Applying the sequence conservation test, four proteins (FliK, BcsZ, FhuA and FepA) remained as potential vaccine candidates for in vivo evaluation of immunogenicity and immunoprotection. All four candidates were capable to trigger the immune response and stimulate the production of antiserum in mice. Furthermore, top-ranked proteins including FliK and BcsZ provided wide antigenic coverage among the multi-serotype of Salmonella. The S. Typhimurium LT2 challenge model used in mice immunized with FliK and BcsZ showed a high relative percentage survival (RPS) of 52.74 % and 64.71 % respectively. In conclusion, this study constructed an in-silico pipeline able to successfully pre-screen the vaccine targets characterized by high immunogenicity and protective immunity. We show that reverse vaccinology allowed screening of appropriate broad-spectrum vaccines for Salmonella.
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114
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Ahmed SO, Zedan HH, Ibrahim YM. Quorum sensing inhibitory effect of bergamot oil and aspidosperma extract against Chromobacterium violaceum and Pseudomonas aeruginosa. Arch Microbiol 2021; 203:4663-4675. [PMID: 34175964 DOI: 10.1007/s00203-021-02455-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/21/2021] [Accepted: 06/21/2021] [Indexed: 10/21/2022]
Abstract
Quorum sensing (QS) represents a major target for reducing bacterial pathogenicity and antibiotic resistance. This study identifies bergamot and aspidosperma as new potential sources of anti-QS agents. We investigated the anti-QS activity of plant materials on both Chromobacterium violaceum and Pseudomonas aeruginosa. Initially, we determined the minimum inhibitory concentrations (MICs) of plant materials using a broth microdilution method. Subsequently, we tested the effect of sub-MIC concentrations on QS-regulated traits and virulence factors production in test bacteria. Results revealed that bergamot and aspidosperma inhibited the ability of C. violaceum to produce violacein. Other QS-controlled phenotypes of C. violaceum, namely chitinolytic activity, motility, and biofilm formation, were also reduced by both plant materials. Moreover, QS-linked traits of P. aeruginosa were also reduced. Bergamot inhibited swarming but not swimming motility, while aspidosperma diminished both motility types in P. aeruginosa. Both plant materials also demonstrated antibiofilm activity and inhibited the production of protease and pyocyanin in P. aeruginosa. Furthermore, we tested the anti-QS effect of plant materials on the transcriptional level using RT-qPCR. Bergamot dramatically downregulated the C. violaceum autoinducer synthase gene cviI and the vioB gene involved in violacein biosynthesis, confirming the phenotypic observation on its anti-QS activity. Aspidosperma also reduced the expression of cviI and vioB but less drastically than bergamot. In P. aeruginosa, downregulation in the transcripts of the QS genes lasI, lasR, rhlI, and rhlR was also achieved by bergamot and aspidosperma. Therefore, data in the present study suggest the usefulness of bergamot and aspidosperma as sources of antivirulence agents.
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Affiliation(s)
- Sarah Omar Ahmed
- Department of Microbiology, General Division of Basic Medical Sciences, Egyptian Drug Authority (EDA), Formerly National Organization for Drug Control and Research (NODCAR), Giza, 12611, Egypt
| | - Hamdallah Hafez Zedan
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Yasser Musa Ibrahim
- Department of Microbiology, General Division of Basic Medical Sciences, Egyptian Drug Authority (EDA), Formerly National Organization for Drug Control and Research (NODCAR), Giza, 12611, Egypt.
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115
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Pun M, Khazanov N, Galsurker O, Weitman M, Kerem Z, Senderowitz H, Yedidia I. Phloretin, an Apple Phytoalexin, Affects the Virulence and Fitness of Pectobacterium brasiliense by Interfering With Quorum-Sensing. FRONTIERS IN PLANT SCIENCE 2021; 12:671807. [PMID: 34249044 PMCID: PMC8270676 DOI: 10.3389/fpls.2021.671807] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/31/2021] [Indexed: 05/31/2023]
Abstract
The effects of phloretin a phytoalexin from apple, was tested on Pectobacterium brasiliense (Pb1692), an emerging soft-rot pathogen of potato. Exposure of Pb1692 to 0.2 mM phloretin a concentration that does not affect growth, or to 0.4 mM a 50% growth inhibiting concentration (50% MIC), reduced motility, biofilm formation, secretion of plant cell wall-degrading enzymes, production of acyl-homoserine lactone (AHL) signaling molecules and infection, phenotypes that are associated with bacterial population density-dependent system known as quorum sensing (QS). To analyze the effect of growth inhibition on QS, the activity of ciprofloxacin, an antibiotic that impairs cell division, was compared to that of phloretin at 50% MIC. Unlike phloretin, the antibiotic hardly affected the tested phenotypes. The use of DH5α, a QS-negative Escherichia coli strain, transformed with an AHL synthase (ExpI) from Pb1692, allowed to validate direct inhibition of AHL production by phloretin, as demonstrated by two biosensor strains, Chromobacterium violaceaum (CV026) and E. coli (pSB401). Expression analysis of virulence-related genes revealed downregulation of QS-regulated genes (expI, expR, luxS, rsmB), plant cell wall degrading enzymes genes (pel, peh and prt) and motility genes (motA, fim, fliA, flhC and flhD) following exposure to both phloretin concentrations. The results support the inhibition of ExpI activity by phloretin. Docking simulations were used to predict the molecular associations between phloretin and the active site of ExpI, to suggest a likely mode of action for the compound's inhibition of virulence.
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Affiliation(s)
- Manoj Pun
- The Institute of Plant Sciences, Volcani Center, Agricultural Research Organization (ARO), Rishon Lezion, Israel
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Netaly Khazanov
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
| | - Ortal Galsurker
- The Institute of Plant Sciences, Volcani Center, Agricultural Research Organization (ARO), Rishon Lezion, Israel
| | - Michal Weitman
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
| | - Zohar Kerem
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | | | - Iris Yedidia
- The Institute of Plant Sciences, Volcani Center, Agricultural Research Organization (ARO), Rishon Lezion, Israel
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116
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Interplay between OmpA and RpoN Regulates Flagellar Synthesis in Stenotrophomonas maltophilia. Microorganisms 2021; 9:microorganisms9061216. [PMID: 34199787 PMCID: PMC8229486 DOI: 10.3390/microorganisms9061216] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 01/17/2023] Open
Abstract
OmpA, which encodes outer membrane protein A (OmpA), is the most abundant transcript in Stenotrophomonas maltophilia based on transcriptome analyses. The functions of OmpA, including adhesion, biofilm formation, drug resistance, and immune response targets, have been reported in some microorganisms, but few functions are known in S. maltophilia. This study aimed to elucidate the relationship between OmpA and swimming motility in S. maltophilia. KJΔOmpA, an ompA mutant, displayed compromised swimming and failure of conjugation-mediated plasmid transportation. The hierarchical organization of flagella synthesis genes in S. maltophilia was established by referencing the Pseudomonas aeruginosa model and was confirmed using mutant construction, qRT-PCR, and functional assays. Distinct from the P. aeruginosa model, rpoN, rather than fleQ and fliA, was at the top of the flagellar regulatory cascade in S. maltophilia. To elucidate the underlying mechanism responsible for ΔompA-mediated swimming compromise, transcriptome analysis of KJ and KJΔOmpA was performed and revealed rpoN downregulation in KJΔOmpA as the key element. The involvement of rpoN in ΔompA-mediated swimming compromise was verified using rpoN complementation, qRT-PCR, and function assays. Collectively, OmpA, which contributes to bacterial conjugation and swimming, is a promising target for adjuvant design in S. maltophilia.
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117
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Chen W, Mani N, Karani H, Li H, Mani S, Tang JX. Confinement discerns swarmers from planktonic bacteria. eLife 2021; 10:e64176. [PMID: 33884952 PMCID: PMC8112864 DOI: 10.7554/elife.64176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 04/21/2021] [Indexed: 12/14/2022] Open
Abstract
Powered by flagella, many bacterial species exhibit collective motion on a solid surface commonly known as swarming. As a natural example of active matter, swarming is also an essential biological phenotype associated with virulence, chemotaxis, and host pathogenesis. Physical changes like cell elongation and hyper-flagellation have been shown to accompany the swarming phenotype. Less studied, however, are the contrasts of collective motion between the swarming cells and their counterpart planktonic cells of comparable cell density. Here, we show that confining bacterial movement in circular microwells allows distinguishing bacterial swarming from collective swimming. On a soft agar plate, a novel bacterial strain Enterobacter sp. SM3 in swarming and planktonic states exhibited different motion patterns when confined to circular microwells of a specific range of sizes. When the confinement diameter was between 40 μm and 90 μm, swarming SM3 formed a single-swirl motion pattern in the microwells whereas planktonic SM3 formed multiple swirls. Similar differential behavior is observed across several other species of gram-negative bacteria. We also observed 'rafting behavior' of swarming bacteria upon dilution. We hypothesize that the rafting behavior might account for the motion pattern difference. We were able to predict these experimental features via numerical simulations where swarming cells are modeled with stronger cell-cell alignment interaction. Our experimental design using PDMS microchip disk arrays enabled us to observe bacterial swarming on murine intestinal surface, suggesting a new method for characterizing bacterial swarming under complex environments, such as in polymicrobial niches, and for in vivo swarming exploration.
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Affiliation(s)
- Weijie Chen
- Department of Physics, Brown UniversityProvidenceUnited States
- Department of Medicine, Albert Einstein College of MedicineBronxUnited States
| | - Neha Mani
- Department of Physics, Brown UniversityProvidenceUnited States
| | - Hamid Karani
- Department of Physics, Brown UniversityProvidenceUnited States
| | - Hao Li
- Department of Medicine, Albert Einstein College of MedicineBronxUnited States
| | - Sridhar Mani
- Department of Medicine, Albert Einstein College of MedicineBronxUnited States
| | - Jay X Tang
- Department of Physics, Brown UniversityProvidenceUnited States
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118
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Zhang X, Zhou D, Bai H, Liu Q, Xiao XL, Yu YG. Comparative transcriptome analysis of virulence genes of enterohemorrhagic Escherichia coli O157:H7 to acid stress. FOOD BIOTECHNOL 2021. [DOI: 10.1080/08905436.2021.1908345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xiaowei Zhang
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Donggen Zhou
- Ningbo International Travel Healthcare Center, Ningbo City, Haishu District, China
| | - Hong Bai
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Qijun Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Xing-Long Xiao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Yi-Gang Yu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
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119
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Chang Y, Carroll BL, Liu J. Structural basis of bacterial flagellar motor rotation and switching. Trends Microbiol 2021; 29:1024-1033. [PMID: 33865677 DOI: 10.1016/j.tim.2021.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 01/08/2023]
Abstract
The bacterial flagellar motor, a remarkable rotary machine, can rapidly switch between counterclockwise (CCW) and clockwise (CW) rotational directions to control the migration behavior of the bacterial cell. The flagellar motor consists of a bidirectional spinning rotor surrounded by torque-generating stator units. Recent high-resolution in vitro and in situ structural studies have revealed stunning details of the individual components of the flagellar motor and their interactions in both the CCW and CW senses. In this review, we discuss these structures and their implications for understanding the molecular mechanisms underlying flagellar rotation and switching.
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Affiliation(s)
- Yunjie Chang
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Brittany L Carroll
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA.
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120
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Wadhwa N, Tu Y, Berg HC. Mechanosensitive remodeling of the bacterial flagellar motor is independent of direction of rotation. Proc Natl Acad Sci U S A 2021; 118:e2024608118. [PMID: 33876769 PMCID: PMC8054018 DOI: 10.1073/pnas.2024608118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Motility is important for the survival and dispersal of many bacteria, and it often plays a role during infections. Regulation of bacterial motility by chemical stimuli is well studied, but recent work has added a new dimension to the problem of motility control. The bidirectional flagellar motor of the bacterium Escherichia coli recruits or releases torque-generating units (stator units) in response to changes in load. Here, we show that this mechanosensitive remodeling of the flagellar motor is independent of direction of rotation. Remodeling rate constants in clockwise rotating motors and in counterclockwise rotating motors, measured previously, fall on the same curve if plotted against torque. Increased torque decreases the off rate of stator units from the motor, thereby increasing the number of active stator units at steady state. A simple mathematical model based on observed dynamics provides quantitative insight into the underlying molecular interactions. The torque-dependent remodeling mechanism represents a robust strategy to quickly regulate output (torque) in response to changes in demand (load).
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Affiliation(s)
- Navish Wadhwa
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138;
- Rowland Institute at Harvard, Harvard University, Cambridge, MA 02142
| | - Yuhai Tu
- T. J. Watson Research Center, IBM, Yorktown Heights, NY 10598
| | - Howard C Berg
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
- Rowland Institute at Harvard, Harvard University, Cambridge, MA 02142
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121
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Yang K, Kao C, Su MS, Wang S, Chen Y, Hu S, Chen J, Teng C, Tsai P, Wu J. Glycosyltransferase Jhp0106 (PseE) contributes to flagellin maturation in Helicobacter pylori. Helicobacter 2021; 26:e12787. [PMID: 33586844 PMCID: PMC7988653 DOI: 10.1111/hel.12787] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 01/25/2023]
Abstract
BACKGROUND Flagella-mediated motility is both a crucial virulence determinant of Helicobacter pylori and a factor associated with gastrointestinal diseases. Flagellar formation requires flagellins to be glycosylated with pseudaminic acid (Pse), a process that has been extensively studied. However, the transfer of Pse to flagellins remains poorly understood. Therefore, the aim of this study is to characterize a putative glycosyltransferase jhp0106 in flagellar formation. MATERIALS AND METHODS Western blotting and chemical deglycosylation were performed to examine FlaA glycosylation. Protein structural analyses were executed to identify the active site residues of Jhp0106, while the Jhp0106-FlaA interaction was examined using a bacterial two-hybrid assay. Lastly, site-directed mutants with mutated active site residues in the jhp0106 gene were generated and investigated using a motility assay, Western blotting, cDNA-qPCR analysis, and electron microscopic examination. RESULTS Loss of flagellar formation in the Δjhp0106 mutant was confirmed to be associated with non-glycosylated FlaA. Furthermore, three active site residues of Jhp0106 (S350, F376, and E415) were identified within a potential substrate-binding region. The interaction between FlaA and Jhp0106, Jhp0106::S350A, Jhp0106::F376A, or Jhp0106::E415A was determined to be significant. As well, the substitution of S350A, F376A, or E415A in the site-directed Δjhp0106 mutants resulted in impaired motility, deficient FlaA glycosylation, and lacking flagella. However, these phenotypic changes were regardless of flaA expression, implying an indefinite proteolytic degradation of FlaA occurred. CONCLUSIONS This study demonstrated that Jhp0106 (PseE) binds to FlaA mediating FlaA glycosylation and flagellar formation. Our discovery of PseE has revealed a new glycosyltransferase family responsible for flagellin glycosylation in pathogens.
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Affiliation(s)
- Kai‐Yuan Yang
- Institute of Microbiology and ImmunologySchool of Life ScienceNational Yang‐Ming UniversityTaipeiTaiwan
| | - Cheng‐Yen Kao
- Institute of Microbiology and ImmunologySchool of Life ScienceNational Yang‐Ming UniversityTaipeiTaiwan,Department of Biotechnology and Laboratory Science in MedicineSchool of Biomedical Science and EngineeringNational Yang‐Ming UniversityTaipeiTaiwan
| | - Marcia Shu‐Wei Su
- Department of Biotechnology and Laboratory Science in MedicineSchool of Biomedical Science and EngineeringNational Yang‐Ming UniversityTaipeiTaiwan
| | - Shuying Wang
- Department of Microbiology and ImmunologyCollege of MedicineNational Cheng‐Kung UniversityTainanTaiwan
| | - Yueh‐Lin Chen
- Department of Biotechnology and Laboratory Science in MedicineSchool of Biomedical Science and EngineeringNational Yang‐Ming UniversityTaipeiTaiwan
| | - Shiau‐Ting Hu
- Institute of Microbiology and ImmunologySchool of Life ScienceNational Yang‐Ming UniversityTaipeiTaiwan
| | - Jenn‐Wei Chen
- Department of Microbiology and ImmunologyCollege of MedicineNational Cheng‐Kung UniversityTainanTaiwan
| | - Ching‐Hao Teng
- Institute of Molecular MedicineCollege of MedicineNational Cheng Kung UniversityTainanTaiwan
| | - Pei‐Jane Tsai
- Department of Medical Laboratory Science and BiotechnologyCollege of MedicineNational Cheng Kung UniversityTainanTaiwan
| | - Jiunn‐Jong Wu
- Department of Biotechnology and Laboratory Science in MedicineSchool of Biomedical Science and EngineeringNational Yang‐Ming UniversityTaipeiTaiwan
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122
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Meng J, Young G, Chen J. The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation. Front Microbiol 2021; 12:627104. [PMID: 33658986 PMCID: PMC7917084 DOI: 10.3389/fmicb.2021.627104] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022] Open
Abstract
The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system's control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.
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Affiliation(s)
- Jiao Meng
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Glenn Young
- Department of Food Science and Technology, University of California, Davis, Davis, CA, United States
| | - Jingyu Chen
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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123
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Acres JM, Youngapelian MJ, Nadeau J. The influence of spaceflight and simulated microgravity on bacterial motility and chemotaxis. NPJ Microgravity 2021; 7:7. [PMID: 33619250 PMCID: PMC7900230 DOI: 10.1038/s41526-021-00135-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/22/2021] [Indexed: 01/31/2023] Open
Abstract
As interest in space exploration rises, there is a growing need to quantify the impact of microgravity on the growth, survival, and adaptation of microorganisms, including those responsible for astronaut illness. Motility is a key microbial behavior that plays important roles in nutrient assimilation, tissue localization and invasion, pathogenicity, biofilm formation, and ultimately survival. Very few studies have specifically looked at the effects of microgravity on the phenotypes of microbial motility. However, genomic and transcriptomic studies give a broad general picture of overall gene expression that can be used to predict motility phenotypes based upon selected genes, such as those responsible for flagellar synthesis and function and/or taxis. In this review, we focus on specific strains of Gram-negative bacteria that have been the most studied in this context. We begin with a discussion of Earth-based microgravity simulation systems and how they may affect the genes and phenotypes of interest. We then summarize results from both Earth- and space-based systems showing effects of microgravity on motility-related genes and phenotypes.
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Affiliation(s)
| | | | - Jay Nadeau
- grid.262075.40000 0001 1087 1481Portland State University, Portland, OR USA
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124
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Mea HJ, Yong PVC, Wong EH. An overview of Acinetobacter baumannii pathogenesis: Motility, adherence and biofilm formation. Microbiol Res 2021; 247:126722. [PMID: 33618061 DOI: 10.1016/j.micres.2021.126722] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.
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Affiliation(s)
- Hing Jian Mea
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Phelim Voon Chen Yong
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Eng Hwa Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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125
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McDonald ND, Boyd EF. Structural and Biosynthetic Diversity of Nonulosonic Acids (NulOs) That Decorate Surface Structures in Bacteria. Trends Microbiol 2021; 29:142-157. [PMID: 32950378 PMCID: PMC7855311 DOI: 10.1016/j.tim.2020.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
Nonulosonic acids (NulOs) are a diverse family of 9-carbon α-keto acid sugars that are involved in a wide range of functions across all branches of life. The family of NulOs includes the sialic acids as well as the prokaryote-specific NulOs. Select bacteria biosynthesize the sialic acid N-acetylneuraminic acid (Neu5Ac), and the ability to produce this sugar and its subsequent incorporation into cell-surface structures is implicated in a variety of bacteria-host interactions. Furthermore, scavenging of sialic acid from the environment for energy has been characterized across a diverse group of bacteria, mainly human commensals and pathogens. In addition to sialic acid, bacteria have the ability to biosynthesize prokaryote-specific NulOs, of which there are several known isomers characterized. These prokaryotic NulOs are similar in structure to Neu5Ac but little is known regarding their role in bacterial physiology. Here, we discuss the diversity in structure, the biosynthesis pathways, and the functions of bacteria-specific NulOs. These carbohydrates are phylogenetically widespread among bacteria, with numerous structurally unique modifications recognized. Despite the diversity in structure, the NulOs are involved in similar functions such as motility, biofilm formation, host colonization, and immune evasion.
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Affiliation(s)
- Nathan D McDonald
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - E Fidelma Boyd
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
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126
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Sy BM, Tree JJ. Small RNA Regulation of Virulence in Pathogenic Escherichia coli. Front Cell Infect Microbiol 2021; 10:622202. [PMID: 33585289 PMCID: PMC7873438 DOI: 10.3389/fcimb.2020.622202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/10/2020] [Indexed: 11/17/2022] Open
Abstract
Enteric and extraintestinal pathotypes of Escherichia coli utilize a wide range of virulence factors to colonize niches within the human body. During infection, virulence factors such as adhesins, secretions systems, or toxins require precise regulation and coordination to ensure appropriate expression. Additionally, the bacteria navigate rapidly changing environments with fluctuations in pH, temperature, and nutrient levels. Enteric pathogens utilize sophisticated, interleaved systems of transcriptional and post-transcriptional regulation to sense and respond to these changes and modulate virulence gene expression. Regulatory small RNAs and RNA-binding proteins play critical roles in the post-transcriptional regulation of virulence. In this review we discuss how the mosaic genomes of Escherichia coli pathotypes utilize small RNA regulation to adapt to their niche and become successful human pathogens.
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Affiliation(s)
- Brandon M Sy
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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127
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Antani JD, Sumali AX, Lele TP, Lele PP. Asymmetric random walks reveal that the chemotaxis network modulates flagellar rotational bias in Helicobacter pylori. eLife 2021; 10:63936. [PMID: 33493107 PMCID: PMC7834020 DOI: 10.7554/elife.63936] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 01/12/2021] [Indexed: 12/14/2022] Open
Abstract
The canonical chemotaxis network modulates the bias for a particular direction of rotation in the bacterial flagellar motor to help the cell migrate toward favorable chemical environments. How the chemotaxis network in Helicobacter pylori modulates flagellar functions is unknown, which limits our understanding of chemotaxis in this species. Here, we determined that H. pylori swim faster (slower) whenever their flagella rotate counterclockwise (clockwise) by analyzing their hydrodynamic interactions with bounding surfaces. This asymmetry in swimming helped quantify the rotational bias. Upon exposure to a chemo-attractant, the bias decreased and the cells tended to swim exclusively in the faster mode. In the absence of a key chemotaxis protein, CheY, the bias was zero. The relationship between the reversal frequency and the rotational bias was unimodal. Thus, H. pylori’s chemotaxis network appears to modulate the probability of clockwise rotation in otherwise counterclockwise-rotating flagella, similar to the canonical network.
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Affiliation(s)
- Jyot D Antani
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Anita X Sumali
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Tanmay P Lele
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77840, College Station, TX 77840, United States.,Department of Translational Medical Sciences, Texas A&M University, Houston, TX 77030, United States
| | - Pushkar P Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
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128
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Yang Q, Zou P, Cao Z, Wang Q, Fu S, Xie G, Huang J. QseC Inhibition as a Novel Antivirulence Strategy for the Prevention of Acute Hepatopancreatic Necrosis Disease (AHPND)-Causing Vibrio parahaemolyticus. Front Cell Infect Microbiol 2021; 10:594652. [PMID: 33553003 PMCID: PMC7859628 DOI: 10.3389/fcimb.2020.594652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/04/2020] [Indexed: 11/13/2022] Open
Abstract
Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus resulted in great economic losses in global shrimp aquaculture. There is an urgent need for development of novel strategies to combat AHPND-causing V. parahaemolyticus (Vp AHPND), given that one of the greatest challenges currently is the widespread use of antibiotics and subsequent emergence of multidrug-resistant bacteria. Here, we proposed a broad-spectrum antivirulence approach targeting a conserved histidine kinase, QseC, which has been demonstrated to activate virulence expression in several Gram-negative pathogens. Our results showed that QseC mediated the catecholamine stimulated effects on growth and flagellar motility of Vp AHPND. Transcriptome analysis revealed that QseC was involved in the global regulation of the virulence of Vp AHPND as the ΔqseC mutant exhibited a decreased expression of genes related to type IV pilin, flagellar motility, and biofilm formation, while an overexpression of type VI secretion system and cell wall biosynthesis. Subsequently, the bacterial catecholamine receptor antagonist LED209 not only neutralized the stimulatory effects of host catecholamines on the growth and motility of Vp AHPND in vitro, but also attenuated the virulence of Vp AHPND towards brine shrimp larvae and white shrimp in vivo. Additionally, LED209 presented no interference with pathogen growth, nor the toxicity to the experimental animals. These results suggest that QseC can be an attractive antivirulence therapy target, and LED209 is a promising candidate for development of broad-spectrum antivirulence agents. This is the first study that demonstrated the role of QseC in the global regulation of Vp AHPND infection and demonstrated the antivirulence potential of LED209, which provides insight into the use of an antivirulence approach for targeting not only Vp AHPND, but also a much larger collection of pathogenic bacteria.
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Affiliation(s)
- Qian Yang
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao, China.,Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.,Center for Microbial Ecology and Technology (CMET), Ghent University, Gent, Belgium
| | - Peizhuo Zou
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao, China.,Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Zhi Cao
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao, China.,Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Qingyao Wang
- College of Marine Science and Environment, Dalian Ocean University, Dalian, China.,Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, Dalian, China
| | - Songzhe Fu
- College of Marine Science and Environment, Dalian Ocean University, Dalian, China.,Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, Dalian, China
| | - Guosi Xie
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao, China.,Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Jie Huang
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao, China.,Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.,Network of Aquaculture Centers in Asia-Pacific, Bangkok, Thailand
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129
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Expansion of Necrosis Depending on Hybrid Motor-Driven Motility of Aeromonas hydrophila in a Murine Wound Infection Model. Microorganisms 2020; 9:microorganisms9010010. [PMID: 33375129 PMCID: PMC7822177 DOI: 10.3390/microorganisms9010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/04/2022] Open
Abstract
The gram-negative bacterium Aeromonas hydrophila is a cause of fulminant and lethal necrotizing soft tissue infections (NSTIs). Suppressing the rapid proliferation of the pathogen and expansion of the necrosis caused in the host is an important issue in clinical practice, but the pathogenic mechanism for the rapid aggravation has not been clarified. In this study, we characterized the function of two types of motor stators in A. hydrophila and explored the role of motility during wound infection. In vitro analysis showed that the motility was reliably maintained while being complemented by the stators. We created a non-motile strain that lacked genes encoding two types of motor stators and analyzed the role of motility in a murine wound infection model. Examination of the bacterial burden in the local infection site and systemic circulation revealed that motility was not essential for the proliferation of A. hydrophila in the host. However, the extent of necrosis at the lesions was lower, and survival times were prolonged in mice infected with the non-motile strain compared with mice infected with the parent strain. These results provide evidence that the rapid expansion of necrosis and the progression to death within a short time period is dependent on the motility of A. hydrophila.
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130
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V. K, Neela VK. Twitching motility of Stenotrophomonas maltophilia under iron limitation: In-silico, phenotypic and proteomic approaches. Virulence 2020; 11:104-112. [PMID: 31957553 PMCID: PMC6984648 DOI: 10.1080/21505594.2020.1713649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/18/2019] [Accepted: 12/02/2019] [Indexed: 10/26/2022] Open
Abstract
This study investigates the twitching ability of 28 clinical and five environmental strains of S. maltophilia grown under iron-depleted condition through in-silico, phenotypic and proteomics approaches. Rapid Annotations using Subsystem Technology (RAST) analysis revealed the presence of 21 targets of type IV pilus shared across S. maltophilia strains K279a, R551-3, D457 and JV3. The macroscopic twitching assay showed that only clinical isolates produced a zone of twitching with a mean of 22.00 mm under normal and 25.00 mm under iron-depleted conditions. (p = 0.002). Environmental isolates did not show any significant twitching activity in both conditions tested. Isobaric Tags for Relative and Absolute Quantification (ITRAQ) analysis showed altered expression of twitching motility protein PilT (99.08-fold change), flagellar biosynthesis protein FliC (20.14-fold change), and fimbrial protein (0.70-fold change) in response to iron-depleted condition. Most of the strains that have the ability to twitch under the normal condition, exhibit enhanced twitching during iron limitation.
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Affiliation(s)
- Kalidasan V.
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Vasantha Kumari Neela
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
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131
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Abstract
Dickeya zeae is the etiological agent of bacterial foot rot disease, which can cause massive economic losses in banana and rice plantations. Genome sequence analysis showed that D. zeae strain EC1 contains multiple c-di-GMP turnover genes, but their roles and regulatory mechanisms in bacterial physiology and virulence remain vague. By generating consecutive in-frame deletion mutants of the genes encoding c-di-GMP biosynthesis and degradation, respectively, we analyzed the individual and collective impacts of these c-di-GMP metabolic genes on the c-di-GMP global pool, bacterial physiology, and virulence. The significance of our study is in identifying the mechanism of c-di-GMP signaling in strain EC1 more clearly, which expands the c-di-GMP regulating patterns in Gram-negative species. The methods and experimental designs in this research will provide a valuable reference for the exploration of the complex c-di-GMP regulation mechanisms in other bacteria. Dickeya zeae is an important and aggressive bacterial phytopathogen that can cause substantial economic losses in banana and rice plantations. We previously showed that c-di-GMP signaling proteins (cyclases/phosphodiesterases) in D. zeae strain EC1 play a significant role in the bacterial sessile-to-motile transition. To determine whether there is any synergistic effect among these c-di-GMP signaling proteins, we prepared a series of mutant strains by generating consecutive in-frame deletions of the genes encoding diguanylate cyclases (which make c-di-GMP) and phosphodiesterases (which break down c-di-GMP), respectively, using EC1 as a parental strain. The results showed that the complete deletion of all the putative diguanylate cyclases resulted in significantly increased bacterial motility and abrogated biofilm formation but did not appear to affect pathogenicity and virulence factor production. In contrast, the deletion of all the c-di-GMP phosphodiesterase genes disabled motility and prevented the invasion of EC1 into rice seeds. By measuring the c-di-GMP concentrations and swimming motility of all the mutants, we propose that c-di-GMP controlled swimming behavior through a multitiered program in a c-di-GMP concentration-dependent manner, which could be described as an L-shaped regression curve. These features are quite different from those that have been shown for other bacterial species such as Salmonella and Caulobacter crescentus. Further analysis identified three c-di-GMP signaling proteins, i.e., PDE10355, DGC14945, and PDE14950, that play dominant roles in influencing the global c-di-GMP pool of strain EC1. The findings from this study highlight the complexity and plasticity of c-di-GMP regulatory circuits in different bacterial species.
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132
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Das S, Ray S, Arunima A, Sahu B, Suar M. A ROD9 island encoded gene in Salmonella Enteritidis plays an important role in acid tolerance response and helps in systemic infection in mice. Virulence 2020; 11:247-259. [PMID: 32116124 PMCID: PMC7051147 DOI: 10.1080/21505594.2020.1733203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 10/31/2022] Open
Abstract
Salmonella, like other pathogenic bacteria has undergone multiple genomic alterations to adapt itself into specific host environments executing varied degrees of virulence through evolution. Such variations in genome content have been assumed to lead the closely related non-typhoidal serovars, S. Enteritidis, and S. Typhimurium to exhibit Type Three Secretion System -2 (T3SS-2) based diverse colonization and inflammation kinetics. Mutually exclusive genes present in either of the serovars are recently being studied and in our currentwork, we focused on a particular island ROD9, present in S. Enteritidis but not in S. Typhimurium. Earlier reports have identified a few genes from this island to be responsible for virulence in vitro as well as in vivo. In this study, we have identified another gene, SEN1008 from the same island encoding a hypothetical protein to be a potential virulence determinant showing systemic attenuation upon mutation in C57BL/6 mice infection model. The isogenic mutant strain displayed reduced adhesion to epithelial cells in vitro as well as was highly immotile. It was also deficient in intracellular replication in vitro, with a highly suppressed SPI-2and failed to cause acute colitis at 72-h p.i.in vivo. Moreover, on acid exposure, SEN1008 showed 17 folds and 2 fold up-regulations during adaptation and challenge phases,respectively and ΔSEN1008 failed to survive during ATR assay, indicating its role under acid stress. Together, our findings suggested ΔSEN1008 to be significantly attenuated and we propose this gene to be a potent factor responsible for S. Enteritidis pathogenesis.
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Affiliation(s)
- Susmita Das
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | | | - Bikash Sahu
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, India
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133
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Ju J, Xie Y, Yu H, Guo Y, Cheng Y, Qian H, Yao W. Synergistic interactions of plant essential oils with antimicrobial agents: a new antimicrobial therapy. Crit Rev Food Sci Nutr 2020; 62:1740-1751. [PMID: 33207954 DOI: 10.1080/10408398.2020.1846494] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The problem of drug resistance of food borne pathogens is becoming more and more serious. Although traditional antimicrobial agents have good therapeutic effects on a variety of food borne pathogens, more effective antimicrobial agents are still needed to combat the development of drug-resistant food borne pathogens. Plant-based natural essential oils (EOs) are widely used because of their remarkable antimicrobial activity. A potential strategy to address food borne pathogens drug resistance is to use a combination of EOs and antimicrobial agents. Because EOs have multi-target inhibitory effects on microorganisms, combining them with drugs can enhance the activity of the drugs and avoid the emergence of food borne pathogens drug resistance. This paper introduces the main factors affecting the antibacterial activity of EOs and describes methods for evaluating their synergistic antibacterial effects. The possible mechanisms of action of EOs and the synergistic inhibitory effects on pathogens of EOs in combination with antimicrobial agents is described. In summary, the combined use of EOs and existing antimicrobial agents is a promising potential new antibacterial therapy.
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Affiliation(s)
- Jian Ju
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yunfei Xie
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Hang Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yahui Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yuliang Cheng
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - He Qian
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Weirong Yao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
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134
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van Zyl WF, Deane SM, Dicks LM. Molecular insights into probiotic mechanisms of action employed against intestinal pathogenic bacteria. Gut Microbes 2020; 12:1831339. [PMID: 33112695 PMCID: PMC7595611 DOI: 10.1080/19490976.2020.1831339] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Gastrointestinal (GI) diseases, and in particular those caused by bacterial infections, are a major cause of morbidity and mortality worldwide. Treatment is becoming increasingly difficult due to the increase in number of species that have developed resistance to antibiotics. Probiotic lactic acid bacteria (LAB) have considerable potential as alternatives to antibiotics, both in prophylactic and therapeutic applications. Several studies have documented a reduction, or prevention, of GI diseases by probiotic bacteria. Since the activities of probiotic bacteria are closely linked with conditions in the host's GI-tract (GIT) and changes in the population of enteric microorganisms, a deeper understanding of gut-microbial interactions is required in the selection of the most suitable probiotic. This necessitates a deeper understanding of the molecular capabilities of probiotic bacteria. In this review, we explore how probiotic microorganisms interact with enteric pathogens in the GIT. The significance of probiotic colonization and persistence in the GIT is also addressed.
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Affiliation(s)
- Winschau F. van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Shelly M. Deane
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Leon M.T. Dicks
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa,CONTACT Leon M.T. Dicks; Department of Microbiology; Stellenbosch University, Stellenbosch7602, South Africa
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135
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Jessberger N, Dietrich R, Granum PE, Märtlbauer E. The Bacillus cereus Food Infection as Multifactorial Process. Toxins (Basel) 2020; 12:E701. [PMID: 33167492 PMCID: PMC7694497 DOI: 10.3390/toxins12110701] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023] Open
Abstract
The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.
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Affiliation(s)
- Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
| | - Richard Dietrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
| | - Per Einar Granum
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003 NMBU, 1432 Ås, Norway;
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
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136
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Veronica EK, Sara A O, Everardo CQ, Héctor Q, Oscar MC, Elizabeth FR, Irma RP, José AG, Bulmaro C, Rigoberto HC, Juan XC, Ariadnna CC. Proteomics profiles of Cronobacter sakazakii and a fliF mutant: Adherence and invasion in mouse neuroblastoma cells. Microb Pathog 2020; 149:104595. [PMID: 33157215 DOI: 10.1016/j.micpath.2020.104595] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 01/17/2023]
Abstract
Cronobacter sakazakii is an opportunistic foodborne pathogen associated with necrotizing enterocolitis, bacteremia, and meningitis in infants. A comparative proteomic study of C. sakazakii ATCC BAA-894 (CS WT) and a fliF::Tn5 mutant was performed, including the ability of both strains to adhere to and invade N1E-115 cells. To achieve this goal, a nonmotile C. sakazakii ATCC BAA-894 fliF::Tn5 (CS fliF::Tn5) strain was generated using an EZ-Tn5 <KAN-2>Tnp Transposome kit. Analysis of differential protein expression showed that 81.49% (361/443) of the proteins were expressed in both strains, 8.35% (37/443) were exclusively expressed in the CS WT strain, and 10.16% (45/443) were exclusively expressed in the CS fliF::Tn5 strain. The main exclusively expressed proteins in the CS WT strain were classified into the "cell motility" and "signal transduction mechanisms" subcategories. The proteins exclusively expressed in the CS fliF::Tn5 strain were classified into the following subcategories: "intracellular trafficking, secretion, and vesicular transport", "replication, recombination, and repair", "nucleotide transport and metabolism", "carbohydrate transport and metabolism", "coenzyme transport and metabolism", and "lipid transport and metabolism". Expression of the Cpa protein was detected in both strains, but Cpa was more abundant in the CS WT strain than in the CS fliF::Tn5 strain. A significant increase (p = 0.0001) in adherence to N1E-115 cells was observed in the nonmotile CS fliF::Tn5 strain (31.3 × 106 CFU/mL) compared to the CS WT strain (14.5 × 106 CFU/mL). Additionally, the CS WT strain showed a 0.17% invasion frequency in N1E-115 cells, which was significantly higher (p = 0.01) than that of the nonmotile CS fliF::Tn5 strain. In conclusion, the proteins involved in the motility were mainly identified by proteomic analysis in the CS WT strain compared to the CS fliF::Tn5 strain. Our data indicate that flagella are required to promote the invasion of N1E-115 cells and that the absence of flagella significantly increases the adherence to N1E-115 cells.
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Affiliation(s)
- Esteban-Kenel Veronica
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico; Laboratorio de Ingeniería Genética, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Ochoa Sara A
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Curiel-Quesada Everardo
- Laboratorio de Ingeniería Genética, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Quezada Héctor
- Unidad de Investigación Epidemiológica en Endocrinología y Nutrición. Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Medina-Contreras Oscar
- Unidad de Investigación Epidemiológica en Endocrinología y Nutrición. Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Fernández-Rendón Elizabeth
- Laboratorio de Microbiología Sanitaria, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Rosas-Pérez Irma
- Laboratorio de Aerobiología, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Arellano-Galindo José
- Área de Virología, Laboratorio de Infectología, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Cisneros Bulmaro
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Hernandez-Castro Rigoberto
- Departamento de Ecología de Agentes Patógenos. Hospital General "Dr. Manuel Gea González", Delegación Tlalpan, México D., 14080, Mexico
| | - Xicohtencatl-Cortes Juan
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico.
| | - Cruz-Córdova Ariadnna
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico.
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137
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Tang Y, Xin G, Zhao LM, Huang LX, Qin YX, Su YQ, Zheng WQ, Wu B, Lin N, Yan QP. Novel insights into host-pathogen interactions of large yellow croakers ( Larimichthys crocea) and pathogenic bacterium Pseudomonas plecoglossicida using time-resolved dual RNA-seq of infected spleens. Zool Res 2020; 41:314-327. [PMID: 32242645 PMCID: PMC7231473 DOI: 10.24272/j.issn.2095-8137.2020.035] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Host-pathogen interactions are highly complex, involving large dynamic changes in gene expression during infection. These interactions are fundamental to understanding anti-infection immunity of hosts, as well as the pathogenesis of pathogens. For bacterial pathogens interacting with animal hosts, time-resolved dual RNA-seq of infected tissue is difficult to perform due to low pathogen load in infected tissue. In this study, an acute infection model of Larimichthys crocea infected by Pseudomonas plecoglossicida was established. The spleens of infected fish exhibited typical symptoms, with a maximum bacterial load at two days post-injection (dpi). Time-resolved dual RNA-seq of infected spleens was successfully applied to study host-pathogen interactions between L. crocea and P. plecoglossicida. The spleens of infected L. crocea were subjected to dual RNA-seq, and transcriptome data were compared with those of noninfected spleens or in vitro cultured bacteria. Results showed that pathogen-host interactions were highly dynamically regulated, with corresponding fluctuations in host and pathogen transcriptomes during infection. The expression levels of many immunogenes involved in cytokine-cytokine receptor, Toll-like receptor signaling, and other immune-related pathways were significantly up-regulated during the infection period. Furthermore, metabolic processes and the use of oxygen in L. crocea were strongly affected by P. plecoglossicida infection. The WGCNA results showed that the metabolic process was strongly related to the entire immune process. For P. plecoglossicida, the expression levels of motility-related genes and flagellum assembly-related genes were significantly up-regulated. The results of this study may help to elucidate the interactions between L. crocea and P. plecoglossicida.
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Affiliation(s)
- Yi Tang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Ge Xin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Ling-Min Zhao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Li-Xing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Ying-Xue Qin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Yong-Quan Su
- State Key Laboratory of Large Yellow Croaker Breeding, Ningde Fufa Aquatic Products Co., Ltd., Ningde, Fujian 352000, China
| | - Wei-Qiang Zheng
- State Key Laboratory of Large Yellow Croaker Breeding, Ningde Fufa Aquatic Products Co., Ltd., Ningde, Fujian 352000, China
| | - Bin Wu
- Fujian Provincial Fishery Technical Extention Center, Fuzhou, Fujian 350003, China
| | - Nan Lin
- Fujian Provincial Fishery Technical Extention Center, Fuzhou, Fujian 350003, China
| | - Qing-Pi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde Fufa Aquatic Products Co., Ltd., Ningde, Fujian 352000, China. E-mail:
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138
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De Maayer P, Pillay T, Coutinho TA. Flagella by numbers: comparative genomic analysis of the supernumerary flagellar systems among the Enterobacterales. BMC Genomics 2020; 21:670. [PMID: 32993503 PMCID: PMC7526173 DOI: 10.1186/s12864-020-07085-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/21/2020] [Indexed: 01/17/2023] Open
Abstract
Background Flagellar motility is an efficient means of movement that allows bacteria to successfully colonize and compete with other microorganisms within their respective environments. The production and functioning of flagella is highly energy intensive and therefore flagellar motility is a tightly regulated process. Despite this, some bacteria have been observed to possess multiple flagellar systems which allow distinct forms of motility. Results Comparative genomic analyses showed that, in addition to the previously identified primary peritrichous (flag-1) and secondary, lateral (flag-2) flagellar loci, three novel types of flagellar loci, varying in both gene content and gene order, are encoded on the genomes of members of the order Enterobacterales. The flag-3 and flag-4 loci encode predicted peritrichous flagellar systems while the flag-5 locus encodes a polar flagellum. In total, 798/4028 (~ 20%) of the studied taxa incorporate dual flagellar systems, while nineteen taxa incorporate three distinct flagellar loci. Phylogenetic analyses indicate the complex evolutionary histories of the flagellar systems among the Enterobacterales. Conclusions Supernumerary flagellar loci are relatively common features across a broad taxonomic spectrum in the order Enterobacterales. Here, we report the occurrence of five (flag-1 to flag-5) flagellar loci on the genomes of enterobacterial taxa, as well as the occurrence of three flagellar systems in select members of the Enterobacterales. Considering the energetic burden of maintaining and operating multiple flagellar systems, they are likely to play a role in the ecological success of members of this family and we postulate on their potential biological functions.
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Affiliation(s)
- Pieter De Maayer
- School of Molecular & Cell Biology, University of the Witwatersrand, Wits, 2050, South Africa.
| | - Talia Pillay
- School of Molecular & Cell Biology, University of the Witwatersrand, Wits, 2050, South Africa
| | - Teresa A Coutinho
- Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, 0002, South Africa
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139
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Uppal G, Hu W, Vural DC. Evolution of chemotactic hitchhiking. J Evol Biol 2020; 33:1593-1605. [PMID: 32929788 DOI: 10.1111/jeb.13695] [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: 05/03/2020] [Revised: 08/11/2020] [Accepted: 08/25/2020] [Indexed: 11/29/2022]
Abstract
Bacteria typically reside in heterogeneous environments with various chemogradients where motile cells can gain an advantage over nonmotile cells. Since motility is energetically costly, cells must optimize their swimming speed and behaviour to maximize their fitness. Here, we investigate how cheating strategies might evolve where slow or nonmotile microbes exploit faster ones by sticking together and hitching a ride. Starting with physical and biological first principles, we computationally study the effects of sticking on the evolution of motility in a controlled chemostat environment. We find that stickiness allows for slow cheaters to dominate when chemoattractants are dispersed at intermediate distances. In this case, slow microbes exploit faster ones until they consume the population, leading to a tragedy of commons. For long races, slow microbes do gain an initial advantage from sticking, but eventually fall behind. Here, fast microbes are more likely to stick to other fast microbes and co-operate to increase their own population. We therefore conclude that whether the nature of the hitchhiking interaction is parasitic or mutualistic, depends on the chemoattractant distribution.
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Affiliation(s)
| | - Weiyi Hu
- Mathematics, Sichuan University, Chengdu, China
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140
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Costa MO, Harding JCS. Swine dysentery disease mechanism: Brachyspira hampsonii impairs the colonic immune and epithelial repair responses to induce lesions. Microb Pathog 2020; 148:104470. [PMID: 32889046 DOI: 10.1016/j.micpath.2020.104470] [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: 05/05/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 10/23/2022]
Abstract
Swine dysentery (SD) is a global, production-limiting disease of pigs in commercial farms. It is associated with infection by Brachyspira hyodysenteriae and B. hampsonii, and characterized by mucohaemorrhagic diarrhea and colitis, SD prevention, treatment or control relies heavily on antimicrobials as no commercial vaccines are available. This is linked to our poor understanding of the disease pathogenesis. Our goal was to characterize the host-pathogen interactions during the early stage of infection. We employed dual RNA-seq to profile mRNA and miRNA following 1-h incubation of colonic explants with a pathogenic or a non-pathogenic B. hampsonii strain. Our results suggest that the pathogenic strain more efficiently interfered with the host's ability to activate and build a humoral response (through IL-4/CCR6/KLHL6 interactions), epithelial wound repair mechanisms (associated with LSECtin impairment of macrophages), induced mitochondrial dysfunction (linked to MDR1), and loss of microbiome homeostasis. The pathogenic strain also up-regulated the expression of stress-associated genes, when compared to the non-pathogenic strain. These results shed a light on the pathophysiological mechanisms that lead to SD and will contribute to the development of novel disease control tools.
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Affiliation(s)
- Matheus O Costa
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK. Canada; Department of Population Health, Faculty of Veterinary Medicine, Utrecht University. Utrecht, the Netherlands.
| | - John C S Harding
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK. Canada
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141
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Abe K, Kuribayashi T, Takabe K, Nakamura S. Implications of back-and-forth motion and powerful propulsion for spirochetal invasion. Sci Rep 2020; 10:13937. [PMID: 32811890 PMCID: PMC7434897 DOI: 10.1038/s41598-020-70897-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/06/2020] [Indexed: 12/18/2022] Open
Abstract
The spirochete Leptospira spp. can move in liquid and on a solid surface using two periplasmic flagella (PFs), and its motility is an essential virulence factor for the pathogenic species. Mammals are infected with the spirochete through the wounded dermis, which implies the importance of behaviors on the boundary with such viscoelastic milieu; however, the leptospiral pathogenicity involving motility remains unclear. We used a glass chamber containing a gel area adjoining the leptospiral suspension to resemble host dermis exposed to contaminated water and analyzed the motility of individual cells at the liquid-gel border. Insertion of one end of the cell body to the gel increased switching of the swimming direction. Moreover, the swimming force of Leptospira was also measured by trapping single cells using an optical tweezer. It was found that they can generate [Formula: see text] 17 pN of force, which is [Formula: see text] 30 times of the swimming force of Escherichia coli. The force-speed relationship suggested the load-dependent force enhancement and showed that the power (the work per unit time) for the propulsion is [Formula: see text] 3.1 × 10-16 W, which is two-order of magnitudes larger than the propulsive power of E. coli. The powerful and efficient propulsion of Leptospira using back-and-forth movements could facilitate their invasion.
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Affiliation(s)
- Keigo Abe
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Toshiki Kuribayashi
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Kyosuke Takabe
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Shuichi Nakamura
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
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142
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Xu J, Koizumi N, Nakamura S. Crawling Motility on the Host Tissue Surfaces Is Associated With the Pathogenicity of the Zoonotic Spirochete Leptospira. Front Microbiol 2020; 11:1886. [PMID: 32849465 PMCID: PMC7419657 DOI: 10.3389/fmicb.2020.01886] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial motility is crucial for many pathogenic species in the process of invasion and/or dissemination. The spirochete bacteria Leptospira spp. cause symptoms, such as hemorrhage, jaundice, and nephritis, in diverse mammals including humans. Although loss-of-motility attenuate the spirochete's virulence, the mechanism of the motility-dependent pathogenicity is unknown. Here, focusing on that Leptospira spp. swim in liquid and crawl on solid surfaces, we investigated the spirochetal dynamics on the host tissues by infecting cultured kidney cells from various species with pathogenic and non-pathogenic leptospires. We found that, in the case of the pathogenic leptospires, a larger fraction of bacteria attached to the host cells and persistently traveled long distances using the crawling mechanism. Our results associate the kinetics and kinematic features of the spirochetal pathogens with their virulence.
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Affiliation(s)
- Jun Xu
- Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Nobuo Koizumi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shuichi Nakamura
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Japan
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143
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Gao P, Guo K, Pu Q, Wang Z, Lin P, Qin S, Khan N, Hur J, Liang H, Wu M. oprC Impairs Host Defense by Increasing the Quorum-Sensing-Mediated Virulence of Pseudomonas aeruginosa. Front Immunol 2020; 11:1696. [PMID: 32849593 PMCID: PMC7417366 DOI: 10.3389/fimmu.2020.01696] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/25/2020] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas aeruginosa, found widely in the wild, causes infections in the lungs and several other organs in healthy people but more often in immunocompromised individuals. P. aeruginosa infection leads to inflammasome assembly, pyroptosis, and cytokine release in the host. OprC is one of the bacterial porins abundant in the outer membrane vesicles responsible for channel-forming and copper binding. Recent research has revealed that OprC transports copper, an essential trace element involved in various physiological processes, into bacteria during copper deficiency. Here, we found that oprC deletion severely impaired bacterial motility and quorum-sensing systems, as well as lowered levels of lipopolysaccharide and pyocyanin in P. aeruginosa. In addition, oprC deficiency impeded the stimulation of TLR2 and TLR4 and inflammasome activation, resulting in decreases in proinflammatory cytokines and improved disease phenotypes, such as attenuated bacterial loads, lowered lung barrier damage, and longer mouse survival. Moreover, oprC deficiency significantly alleviated pyroptosis in macrophages. Mechanistically, oprC gene may impact quorum-sensing systems in P. aeruginosa to alter pyroptosis and inflammatory responses in cells and mice through the STAT3/NF-κB signaling pathway. Our findings characterize OprC as a critical virulence regulator, providing the groundwork for further dissection of the pathogenic mechanism of OprC as a potential therapeutic target of P. aeruginosa.
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Affiliation(s)
- Pan Gao
- State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Qinqin Pu
- State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Zhihan Wang
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States.,West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China
| | - Ping Lin
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Shugang Qin
- State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Nadeem Khan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Haihua Liang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Min Wu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
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144
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In vitro Edwardsiella piscicida CK108 Transcriptome Profiles with Subinhibitory Concentrations of Phenol and Formalin Reveal New Insights into Bacterial Pathogenesis Mechanisms. Microorganisms 2020; 8:microorganisms8071068. [PMID: 32709101 PMCID: PMC7409036 DOI: 10.3390/microorganisms8071068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 12/20/2022] Open
Abstract
Phenol and formalin are major water pollutants that are frequently discharged into the aquatic milieu. These chemicals can affect broad domains of life, including microorganisms. Aquatic pollutants, unlike terrestrial pollutants, are easily diluted in water environments and exist at a sub-inhibitory concentration (sub-IC), thus not directly inhibiting bacterial growth. However, they can modulate gene expression profiles. The sub-IC values of phenol and formalin were measured by minimal inhibitory concentration (MIC) assay to be 0.146% (1.3 mM) and 0.0039% (0.38 mM), respectively, in Edwardsiella piscicida CK108, a Gram-negative fish pathogen. We investigated the differentially expressed genes (DEG) by RNA-seq when the cells were exposed to the sub-ICs of phenol and formalin. DEG analyses revealed that genes involved in major virulence factors (type I fimbriae, flagella, type III and type VI secretion system) and various cellular pathways (energy production, amino acid synthesis, carbohydrate metabolism and two-component regulatory systems) were up- or downregulated by both chemicals. The genome-wide gene expression data corresponded to the results of a quantitative reverse complementary-PCR and motility assay. This study not only provides insight into how a representative fish pathogen, E. piscicida CK108, responds to the sub-ICs of phenol and formalin but also shows the importance of controlling chemical pollutants in aquatic environments.
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145
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Liu Y, Filiatrault MJ. Antibacterial activity and mode of action of potassium tetraborate tetrahydrate against soft-rot bacterial plant pathogens. MICROBIOLOGY-SGM 2020; 166:837-848. [PMID: 32639227 PMCID: PMC7654739 DOI: 10.1099/mic.0.000948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial soft rot caused by the bacteria Dickeya and Pectobacterium is a destructive disease of vegetables, as well as ornamental plants. Several management options exist to help control these pathogens. Because of the limited success of these approaches, there is a need for the development of alternative methods to reduce losses. In this study, we evaluated the effect of potassium tetraborate tetrahydrate (PTB) on the growth of six Dickeya and Pectobacterium spp. Disc diffusion assays showed that Dickeya spp. and Pectobacterium spp. differ in their sensitivity to PTB. Spontaneous PTB-resistant mutants of Pectobacterium were identified and further investigation of the mechanism of PTB resistance was conducted by full genome sequencing. Point mutations in genes cpdB and supK were found in a single Pectobacterium atrosepticum PTB-resistant mutant. Additionally, point mutations in genes prfB (synonym supK) and prmC were found in two independent Pectobacterium brasiliense PTB-resistant mutants. prfB and prmC encode peptide chain release factor 2 and its methyltransferase, respectively. We propose the disruption of translation activity due to PTB leads to Pectobacterium growth inhibition. The P. atrosepticum PTB-resistant mutant showed altered swimming motility. Disease severity was reduced for P. atrosepticum-inoculated potato stems sprayed with PTB. We discuss the potential risk of selecting for bacterial resistance to this chemical.
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Affiliation(s)
- Yingyu Liu
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Melanie J. Filiatrault
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
- Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, USA
- *Correspondence: Melanie J. Filiatrault,
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146
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Measurement of the Cell-Body Rotation of Leptospira. Methods Mol Biol 2020. [PMID: 32632866 DOI: 10.1007/978-1-0716-0459-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Leptospira spp. swim in liquid and crawl on surfaces with two periplasmic flagella. The periplasmic flagella attach to the protoplasmic cylinder via basal rotary motors (flagellar motors) and transform the ends of the cell body into spiral or hook shape. The rotations of the periplasmic flagella are thought to gyrate the cell body and rotate the protoplasmic cylinder for propelling the cell; however, the motility mechanism has not been fully elucidated. Since the motility is a critical virulence factor for pathogenic leptospires, the kinematic insight is valuable to understand the mechanism of infection. This chapter describes microscopic methodologies to measure the motility of Leptospira, focusing on rotation of the helical cell body.
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147
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Liu R, Zheng R, Liu G, Sun C. The cyclic lipopeptides suppress the motility of Vibrio alginolyticus via targeting the Na + -driven flagellar motor component MotX. Environ Microbiol 2020; 22:4424-4437. [PMID: 32608186 DOI: 10.1111/1462-2920.15144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/18/2020] [Accepted: 06/28/2020] [Indexed: 01/17/2023]
Abstract
In our previous study, we found that pumilacidin-like cyclic lipopeptides (CLPs) derived from marine bacterium Bacillus sp. strain 176 significantly suppressed the mobile capability and virulence of Vibrio alginolyticus. Here, to further disclose the mechanism of CLPs inhibiting the motility of V. alginolyticus, we first applied transcriptomic analysis to V. alginolyticus treated with or without CLPs. The transcriptomic results showed that the expression of several important components of the Na+ -driven flagellar motor closely related to bacterial motility were markedly suppressed, suggesting that the structure and function of Na+ -driven flagellar motor might be disabled by CLPs. The transcriptomic data were further analysed by the protein-protein interaction network, and the results supported that MotX, one of the essential components of Na+ -driven flagellar motor was most likely the action target of CLPs. In combination of gene knockout, electrophoretic mobility shift assay and immunoblotting techniques, CLPs were demonstrated to affect the rotation of flagella of Vibrio alginolyticus via direct interacting with the Na+ -driven flagellar motor component MotX, which eventually inhibited the bacterial motility. Interestingly, homologues of MotX were found broadly distributed and highly conserved in different pathogenic species, which extends the application range of CLPs as an antibacterial drug targeting bacterial motility in many pathogens.
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Affiliation(s)
- Rui Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Rikuan Zheng
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Ge Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Chaomin Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
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148
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Hirayama S, Nakao R. Glycine significantly enhances bacterial membrane vesicle production: a powerful approach for isolation of LPS-reduced membrane vesicles of probiotic Escherichia coli. Microb Biotechnol 2020; 13:1162-1178. [PMID: 32348028 PMCID: PMC7264892 DOI: 10.1111/1751-7915.13572] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 03/21/2020] [Accepted: 03/22/2020] [Indexed: 01/05/2023] Open
Abstract
Bacterial membrane vesicles (MVs) have attracted strong interest in recent years as novel nanoparticle delivery platforms. Glycine is known to induce morphological changes in the outer layer of bacteria. We report here that glycine dramatically facilitates MV production in a flagella-deficient mutant of the non-pathogenic probiotic Escherichia coli strain Nissle 1917. Supplementation of culture medium with 1.0% glycine induced cell deformation at the early exponential phase, eventually followed by quasi-lysis during the late exponential to stationary phase. Glycine supplementation also significantly increased the number of MVs with enlarged particle size and altered the protein profile with an increase in the inner membrane and cytoplasmic protein contents as compared to non-induced MVs. Of note, the endotoxin activity of glycine-induced MVs was approximately eightfold or sixfold lower than that of non-induced MVs when compared at equal protein or lipid concentrations respectively. Nevertheless, glycine-induced MVs efficiently induced both immune responses in a mouse macrophage-like cell line and adjuvanticity in an intranasal vaccine mouse model, comparable to those of non-induced MVs. We propose that the present method of inducing MV production with glycine can be used for emerging biotechnological applications of MVs that have immunomodulatory activities, while dramatically reducing the presence of endotoxins.
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Affiliation(s)
- Satoru Hirayama
- Department of Bacteriology INational Institute of Infectious Diseases1‐23‐1 ToyamaShinjuku, Tokyo162‐8640Japan
- Japan Agency for Medical Research and Development20F Yomiuri Shimbun Bldg. 1‐7‐1 OtemachiChiyoda, Tokyo100‐0004Japan
| | - Ryoma Nakao
- Department of Bacteriology INational Institute of Infectious Diseases1‐23‐1 ToyamaShinjuku, Tokyo162‐8640Japan
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Transcriptomic analysis reveals the role of RcsB in suppressing bacterial chemotaxis, flagellar assembly and infection in Yersinia enterocolitica. Curr Genet 2020; 66:971-988. [PMID: 32488337 DOI: 10.1007/s00294-020-01083-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/01/2020] [Accepted: 05/01/2020] [Indexed: 12/17/2022]
Abstract
Defining the Rcs (Regulator of Capsule Synthesis) regulon in Enterobacteriaceae has been the major focus of several recent studies. The overall role of the Rcs system in Yersinia enterocolitica is largely unknown. Our previous study showed that RcsB inhibits motility, biofilm formation and c-di-GMP production by negatively regulating flhDC, hmsHFRS and hmsT expression. To identify other cellular functions regulated by the RcsB, gene expression profiles of the wild type and ΔrcsB mutant were compared by RNA-Seq in this study. A total of 132 differentially expressed genes regulated by the RcsB have been identified, of which 114 were upregulated and 18 were downregulated. Further, the results of RNA sequencing were discussed with a focus on the predictive roles of RcsB in the inhibition of bacterial chemotaxis, flagellar assembly and infection. To confirm these predictions, we experimentally verified that the ΔrcsB mutant activated chemotactic behavior and flagella biosynthesis, and exhibited enhanced adhesion and invasion of Y. enterocolitica to Caco-2 cells. Although RcsB largely inhibits these physiological activities, the presence of RcsB is still of great significance for optimizing the survival of Y. enterocolitica as evidenced by our previous report that RcsB confers some level of resistance to the cationic antimicrobial peptide polymyxin B in Y. enterocolitica. Overall, the information provided in this study complements our understanding of Rcs phosphorelay in the regulation of Y. enterocolitica pathogenicity, and, simultaneously, provides clues to additional roles of the Rcs system in other members of family Enterobacteriaceae.
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Agaric acid reduces Salmonella biofilm formation by inhibiting flagellar motility. Biofilm 2020; 2:100022. [PMID: 33447808 PMCID: PMC7798450 DOI: 10.1016/j.bioflm.2020.100022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/11/2020] [Accepted: 03/04/2020] [Indexed: 12/31/2022] Open
Abstract
Salmonella biofilms are a common cause of contaminations in the food or feed industry. In a screening for novel compounds to combat biofilm-associated foodborne outbreaks, we identified agaric acid as a Salmonella Typhimurium biofilm inhibitor that does not affect planktonic growth. Importantly, the remaining biofilm cells after preventive treatment with agaric acid were significantly more sensitive to the common disinfectant hydrogen peroxide. Screening of a GFP-promoter fusion library of biofilm related genes revealed that agaric acid downregulates the transcription of genes responsible for flagellar motility. Concurrently, swimming motility was completely abrogated in the presence of agaric acid, indicating that biofilm inhibition occurs via interference with the motility phenotype. Moreover, agaric acid also reduced biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Agaric acid thus shows potential as an anti-virulence compound that inhibits both motility and biofilm formation.
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