1
|
Ryoo D, Hwang H, Gumbart JC. Thicket and Mesh: How the Outer Membrane Can Resist Tension Imposed by the Cell Wall. J Phys Chem B 2024; 128:5371-5377. [PMID: 38787347 PMCID: PMC11163421 DOI: 10.1021/acs.jpcb.3c08510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
The cell envelope of Gram-negative bacteria is composed of an outer membrane (OM) and an inner membrane (IM) and a peptidoglycan cell wall (CW) between them. Combined with Braun's lipoprotein (Lpp), which connects the OM and the CW, and numerous membrane proteins that exist in both OM and IM, the cell envelope creates a mechanically stable environment that resists various physical and chemical perturbations to the cell, including turgor pressure caused by the solute concentration difference between the cytoplasm of the cell and the extracellular environment. Previous computational studies have explored how individual components (OM, IM, and CW) can resist turgor pressure although combinations of them have been less well studied. To that end, we constructed multiple OM-CW systems, including the Lpp connections with the CW under increasing degrees of strain. The results show that the OM can effectively resist the tension imposed by the CW, shrinking by only 3-5% in area even when the CW is stretched to 2.5× its relaxed area. The area expansion modulus of the system increases with increasing CW strain, although the OM remains a significant contributor to the envelope's mechanical stability. Additionally, we find that when the protein TolC is embedded in the OM, its stiffness increases.
Collapse
Affiliation(s)
- David Ryoo
- Interdisciplinary
Bioengineering Graduate Program, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Hyea Hwang
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - James C. Gumbart
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| |
Collapse
|
2
|
Dye KJ, Salar S, Allen U, Smith W, Yang Z. Myxococcus xanthus PilB interacts with c-di-GMP and modulates motility and biofilm formation. J Bacteriol 2023; 205:e0022123. [PMID: 37695853 PMCID: PMC10521364 DOI: 10.1128/jb.00221-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 08/02/2023] [Indexed: 09/13/2023] Open
Abstract
The regulation of biofilm and motile states as alternate bacterial lifestyles has been studied extensively in flagellated bacteria, where the second messenger cyclic-di-GMP (cdG) plays a crucial role. However, much less is known about the mechanisms of such regulation in motile bacteria without flagella. The bacterial type IV pilus (T4P) serves as a motility apparatus that enables Myxococcus xanthus to move on solid surfaces. PilB, the T4P assembly ATPase, is, therefore, required for T4P-dependent motility in M. xanthus. Interestingly, T4P is also involved in the regulation of exopolysaccharide as the biofilm matrix material in this bacterium. A newly discovered cdG-binding domain, MshEN, is conserved in the N-terminus of PilB (PilBN) in M. xanthus and other bacteria. This suggests that cdG may bind to PilB to control the respective outputs that regulate biofilm development and T4P-powered motility. In this study, we aimed to validate M. xanthus PilB as a cdG effector protein. We performed a systematic mutational analysis of its cdG-binding domain to investigate its relationship with motility, piliation, and biofilm formation. Excluding those resulting in low levels of PilB protein, all other substitution mutations in PilBN resulted in pilB mutants with distinct and differential phenotypes in piliation and biofilm levels in M. xanthus. This suggests that the PilBN domain plays dual roles in modulating motility and biofilm levels, and these two functions of PilB can be dependent on and independent of each other in M. xanthus. IMPORTANCE The regulation of motility and biofilm by cyclic-di-GMP in flagellated bacteria has been extensively investigated. However, our knowledge regarding this regulation in motile bacteria without flagella remains limited. Here, we aimed to address this gap by investigating a non-flagellated bacterium with motility powered by bacterial type-IV pilus (T4P). Previous studies hinted at the possibility of Myxococcus xanthus PilB, the T4P assembly ATPase, serving as a cyclic-di-GMP effector involved in regulating both motility and biofilm. Our findings strongly support the hypothesis that PilB directly interacts with cyclic-di-GMP to act as a potential switch to promote biofilm formation or T4P-dependent motility. These results shed light on the bifurcation of PilB functions and its pivotal role in coordinating biofilm formation and T4P-mediated motility.
Collapse
Affiliation(s)
- Keane J. Dye
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Safoura Salar
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Uvina Allen
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Wraylyn Smith
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Zhaomin Yang
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| |
Collapse
|
3
|
Zhang H, Zhang W, Zong Y, Kong D, Zhao K. Factors Influencing Pseudomonas aeruginosa Initial Adhesion and Evolution at the Dodecane-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:11274-11282. [PMID: 37524061 DOI: 10.1021/acs.langmuir.3c00901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Bacterial adhesion and evolution at the oil-water interface are important for a broad range of applications such as food manufacturing and microbial-enhanced oil recovery, etc. However, our understanding on bacterial interfacial adhesion and evolution, particularly at the single-cell level, is still far from complete. In this work, by employing Pseudomonas aeruginosa PAO1 at the dodecane-water interface as a model system, we have studied the effects of different factors on bacterial interfacial adhesion and the dynamic evolution of bacterial interfacial behavior at the single-cell level. The results show that PAO1 cells displayed a chemotactic behavior toward dodecane. Among the tested factors, bacterial initial interfacial attachment showed a negative correlation with the secreted cell-surface associated lipopolysaccharide and Psl while a positive correlation with type IV pili. Adding nonbiological surfactant Pluronic F-127, as expected, greatly reduced the cell interfacial adhesion. More importantly, the dynamics analysis of cell attachment/detachment at the dodecane-water interface over a long-time scale revealed a reversible to irreversible attachment transition of cells. This transition is accompanied with the interface aging resulting from bacterial activities, which led to an increase of the interfacial viscoelasticity with time and finally the formation of the gel-like interface. Further analysis demonstrated the important role of exopolysaccharides in the latter process. Our findings provide more details of bacterial oil-water interfacial behavior at the single-cell level and may shed light on developing new strategies for controlling bacterial colonization at the oil-water interface.
Collapse
Affiliation(s)
- Hong Zhang
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Wenchao Zhang
- School of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Yiwu Zong
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Dongyang Kong
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Kun Zhao
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and The Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| |
Collapse
|
4
|
Krzyżanowska DM, Jabłońska M, Kaczyński Z, Czerwicka-Pach M, Macur K, Jafra S. Host-adaptive traits in the plant-colonizing Pseudomonas donghuensis P482 revealed by transcriptomic responses to exudates of tomato and maize. Sci Rep 2023; 13:9445. [PMID: 37296159 PMCID: PMC10256816 DOI: 10.1038/s41598-023-36494-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023] Open
Abstract
Pseudomonads are metabolically flexible and can thrive on different plant hosts. However, the metabolic adaptations required for host promiscuity are unknown. Here, we addressed this knowledge gap by employing RNAseq and comparing transcriptomic responses of Pseudomonas donghuensis P482 to root exudates of two plant hosts: tomato and maize. Our main goal was to identify the differences and the common points between these two responses. Pathways upregulated only by tomato exudates included nitric oxide detoxification, repair of iron-sulfur clusters, respiration through the cyanide-insensitive cytochrome bd, and catabolism of amino and/or fatty acids. The first two indicate the presence of NO donors in the exudates of the test plants. Maize specifically induced the activity of MexE RND-type efflux pump and copper tolerance. Genes associated with motility were induced by maize but repressed by tomato. The shared response to exudates seemed to be affected both by compounds originating from the plants and those from their growth environment: arsenic resistance and bacterioferritin synthesis were upregulated, while sulfur assimilation, sensing of ferric citrate and/or other iron carriers, heme acquisition, and transport of polar amino acids were downregulated. Our results provide directions to explore mechanisms of host adaptation in plant-associated microorganisms.
Collapse
Affiliation(s)
- Dorota M Krzyżanowska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdańsk, ul. A. Abrahama 58, 80-307, Gdańsk, Poland
| | - Magdalena Jabłońska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdańsk, ul. A. Abrahama 58, 80-307, Gdańsk, Poland
| | - Zbigniew Kaczyński
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Małgorzata Czerwicka-Pach
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Katarzyna Macur
- Laboratory of Mass Spectrometry, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdańsk, ul. A. Abrahama 58, 80-307, Gdańsk, Poland
| | - Sylwia Jafra
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdańsk, ul. A. Abrahama 58, 80-307, Gdańsk, Poland.
| |
Collapse
|
5
|
Gonçalves ASC, Leitão MM, Simões M, Borges A. The action of phytochemicals in biofilm control. Nat Prod Rep 2023; 40:595-627. [PMID: 36537821 DOI: 10.1039/d2np00053a] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Covering: 2009 to 2021Antimicrobial resistance is now rising to dangerously high levels in all parts of the world, threatening the treatment of an ever-increasing range of infectious diseases. This has becoming a serious public health problem, especially due to the emergence of multidrug-resistance among clinically important bacterial species and their ability to form biofilms. In addition, current anti-infective therapies have low efficacy in the treatment of biofilm-related infections, leading to recurrence, chronicity, and increased morbidity and mortality. Therefore, it is necessary to search for innovative strategies/antibacterial agents capable of overcoming the limitations of conventional antibiotics. Natural compounds, in particular those obtained from plants, have been exhibiting promising properties in this field. Plant secondary metabolites (phytochemicals) can act as antibiofilm agents through different mechanisms of action from the available antibiotics (inhibition of quorum-sensing, motility, adhesion, and reactive oxygen species production, among others). The combination of different phytochemicals and antibiotics have revealed synergistic or additive effects in biofilm control. This review aims to bring together the most relevant reports on the antibiofilm properties of phytochemicals, as well as insights into their structure and mechanistic action against bacterial pathogens, spanning December 2008 to December 2021.
Collapse
Affiliation(s)
- Ariana S C Gonçalves
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Miguel M Leitão
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Manuel Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Anabela Borges
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| |
Collapse
|
6
|
Wang J, Raza W, Jiang G, Yi Z, Fields B, Greenrod S, Friman VP, Jousset A, Shen Q, Wei Z. Bacterial volatile organic compounds attenuate pathogen virulence via evolutionary trade-offs. THE ISME JOURNAL 2023; 17:443-452. [PMID: 36635489 PMCID: PMC9938241 DOI: 10.1038/s41396-023-01356-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/21/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023]
Abstract
Volatile organic compounds (VOCs) produced by soil bacteria have been shown to exert plant pathogen biocontrol potential owing to their strong antimicrobial activity. While the impact of VOCs on soil microbial ecology is well established, their effect on plant pathogen evolution is yet poorly understood. Here we experimentally investigated how plant-pathogenic Ralstonia solanacearum bacterium adapts to VOC-mixture produced by a biocontrol Bacillus amyloliquefaciens T-5 bacterium and how these adaptations might affect its virulence. We found that VOC selection led to a clear increase in VOC-tolerance, which was accompanied with cross-tolerance to several antibiotics commonly produced by soil bacteria. The increasing VOC-tolerance led to trade-offs with R. solanacearum virulence, resulting in almost complete loss of pathogenicity in planta. At the genetic level, these phenotypic changes were associated with parallel mutations in genes encoding lipopolysaccharide O-antigen (wecA) and type-4 pilus biosynthesis (pilM), which both have been linked with outer membrane permeability to antimicrobials and plant pathogen virulence. Reverse genetic engineering revealed that both mutations were important, with pilM having a relatively larger negative effect on the virulence, while wecA having a relatively larger effect on increased antimicrobial tolerance. Together, our results suggest that microbial VOCs are important drivers of bacterial evolution and could potentially be used in biocontrol to select for less virulent pathogens via evolutionary trade-offs.
Collapse
Affiliation(s)
- Jianing Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China
| | - Waseem Raza
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China.
- Institute for Environmental Biology, Ecology & Biodiversity, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Gaofei Jiang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China
| | - Zhang Yi
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China
| | - Bryden Fields
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Samuel Greenrod
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Ville-Petri Friman
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China.
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK.
- Department of Microbiology, University of Helsinki, Helsinki, 00014, Finland.
| | - Alexandre Jousset
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China
| | - Zhong Wei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, PR China.
| |
Collapse
|
7
|
Pseudomonas aeruginosa and Staphylococcus aureus Display Differential Proteomic Responses to the Silver(I) Compound, SBC3. Antibiotics (Basel) 2023; 12:antibiotics12020348. [PMID: 36830259 PMCID: PMC9952281 DOI: 10.3390/antibiotics12020348] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/27/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
The urgent need to combat antibiotic resistance and develop novel antimicrobial therapies has triggered studies on novel metal-based formulations. N-heterocyclic carbene (NHC) complexes coordinate transition metals to generate a broad range of anticancer and/or antimicrobial agents, with ongoing efforts being made to enhance the lipophilicity and drug stability. The lead silver(I) acetate complex, 1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene (NHC*) (SBC3), has previously demonstrated promising growth and biofilm-inhibiting properties. In this work, the responses of two structurally different bacteria to SBC3 using label-free quantitative proteomics were characterised. Multidrug-resistant Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) are associated with cystic fibrosis lung colonisation and chronic wound infections, respectively. SBC3 increased the abundance of alginate biosynthesis, the secretion system and drug detoxification proteins in P. aeruginosa, whilst a variety of pathways, including anaerobic respiration, twitching motility and ABC transport, were decreased in abundance. This contrasted the affected pathways in S. aureus, where increased DNA replication/repair and cell redox homeostasis and decreased protein synthesis, lipoylation and glucose metabolism were observed. Increased abundance of cell wall/membrane proteins was indicative of the structural damage induced by SBC3 in both bacteria. These findings show the potential broad applications of SBC3 in treating Gram-positive and Gram-negative bacteria.
Collapse
|
8
|
Discovery of Two Inhibitors of the Type IV Pilus Assembly ATPase PilB as Potential Antivirulence Compounds. Microbiol Spectr 2022; 10:e0387722. [PMID: 36377931 PMCID: PMC9769694 DOI: 10.1128/spectrum.03877-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
With the pressing antibiotic resistance pandemic, antivirulence has been increasingly explored as an alternative strategy against bacterial infections. The bacterial type IV pilus (T4P) is a well-documented virulence factor and an attractive target for small molecules for antivirulence purposes. The PilB ATPase is essential for T4P biogenesis because it catalyzes the assembly of monomeric pilins into the polymeric pilus filament. Here, we describe the identification of two PilB inhibitors by a high-throughput screen (HTS) in vitro and their validation as effective inhibitors of T4P assembly in vivo. We used Chloracidobacterium thermophilum PilB as a model enzyme to optimize an ATPase assay for the HTS. From a library of 2,320 compounds, benserazide and levodopa, two approved drugs for Parkinson's disease, were identified and confirmed biochemically to be PilB inhibitors. We demonstrate that both compounds inhibited the T4P-dependent motility of the bacteria Myxoccocus xanthus and Acinetobacter nosocomialis. Additionally, benserazide and levodopa were shown to inhibit A. nosocomialis biofilm formation, a T4P-dependent process. Using M. xanthus as a model, we showed that both compounds inhibited T4P assembly in a dose-dependent manner. These results suggest that these two compounds are effective against the PilB protein in vivo. The potency of benserazide and levodopa as PilB inhibitors both in vitro and in vivo demonstrate potentials of the HTS and its two hits here for the development of anti-T4P chemotherapeutics. IMPORTANCE Many bacterial pathogens use their type IV pilus (T4P) to facilitate and maintain an infection in a human host. Small-molecule inhibitors of the production or assembly of the T4P are promising for the treatment and prevention of infections by these bacteria, especially in our fight against antibiotic-resistant pathogens. Here, we report the development and implementation of a method to identify anti-T4P chemicals from compound libraries by high-throughput screen. This led to the identification and validation of two T4P inhibitors both in the test tubes and in bacteria. The discovery and validation pipeline reported here as well as the confirmation of two anti-T4P inhibitors provide new venues and leads for the development of chemotherapeutics against antibiotic-resistant infections.
Collapse
|
9
|
Shanmugasundarasamy T, Karaiyagowder Govindarajan D, Kandaswamy K. A review on pilus assembly mechanisms in Gram-positive and Gram-negative bacteria. Cell Surf 2022; 8:100077. [PMID: 35493982 PMCID: PMC9046445 DOI: 10.1016/j.tcsw.2022.100077] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 12/17/2022] Open
Abstract
The surface of Gram-positive and Gram-negative bacteria contains long hair-like proteinaceous protrusion known as pili or fimbriae. Historically, pilin proteins were considered to play a major role in the transfer of genetic material during bacterial conjugation. Recent findings however elucidate their importance in virulence, biofilm formation, phage transduction, and motility. Therefore, it is crucial to gain mechanistic insights on the subcellular assembly of pili and the localization patterns of their subunit proteins (major and minor pilins) that aid the macromolecular pilus assembly at the bacterial surface. In this article, we review the current knowledge of pilus assembly mechanisms in a wide range of Gram-positive and Gram-negative bacteria, including subcellular localization patterns of a few pilin subunit proteins and their role in virulence and pathogenesis.
Collapse
|
10
|
Keller-Costa T, Kozma L, Silva SG, Toscan R, Gonçalves J, Lago-Lestón A, Kyrpides NC, Nunes da Rocha U, Costa R. Metagenomics-resolved genomics provides novel insights into chitin turnover, metabolic specialization, and niche partitioning in the octocoral microbiome. MICROBIOME 2022; 10:151. [PMID: 36138466 PMCID: PMC9502895 DOI: 10.1186/s40168-022-01343-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/03/2022] [Indexed: 05/31/2023]
Abstract
BACKGROUND The role of bacterial symbionts that populate octocorals (Cnidaria, Octocorallia) is still poorly understood. To shed light on their metabolic capacities, we examined 66 high-quality metagenome-assembled genomes (MAGs) spanning 30 prokaryotic species, retrieved from microbial metagenomes of three octocoral species and seawater. RESULTS Symbionts of healthy octocorals were affiliated with the taxa Endozoicomonadaceae, Candidatus Thioglobaceae, Metamycoplasmataceae, unclassified Pseudomonadales, Rhodobacteraceae, unclassified Alphaproteobacteria and Ca. Rhabdochlamydiaceae. Phylogenomics inference revealed that the Endozoicomonadaceae symbionts uncovered here represent two species of a novel genus unique to temperate octocorals, here denoted Ca. Gorgonimonas eunicellae and Ca. Gorgonimonas leptogorgiae. Their genomes revealed metabolic capacities to thrive under suboxic conditions and high gene copy numbers of serine-threonine protein kinases, type 3-secretion system, type-4 pili, and ankyrin-repeat proteins, suggesting excellent capabilities to colonize, aggregate, and persist inside their host. Contrarily, MAGs obtained from seawater frequently lacked symbiosis-related genes. All Endozoicomonadaceae symbionts harbored endo-chitinase and chitin-binging protein-encoding genes, indicating that they can hydrolyze the most abundant polysaccharide in the oceans. Other symbionts, including Metamycoplasmataceae and Ca. Thioglobaceae, may assimilate the smaller chitin oligosaccharides resulting from chitin breakdown and engage in chitin deacetylation, respectively, suggesting possibilities for substrate cross-feeding and a role for the coral microbiome in overall chitin turnover. We also observed sharp differences in secondary metabolite production potential between symbiotic lineages. Specific Proteobacteria taxa may specialize in chemical defense and guard other symbionts, including Endozoicomonadaceae, which lack such capacity. CONCLUSION This is the first study to recover MAGs from dominant symbionts of octocorals, including those of so-far unculturable Endozoicomonadaceae, Ca. Thioglobaceae and Metamycoplasmataceae symbionts. We identify a thus-far unanticipated, global role for Endozoicomonadaceae symbionts of corals in the processing of chitin, the most abundant natural polysaccharide in the oceans and major component of the natural zoo- and phytoplankton feed of octocorals. We conclude that niche partitioning, metabolic specialization, and adaptation to low oxygen conditions among prokaryotic symbionts likely contribute to the plasticity and adaptability of the octocoral holobiont in changing marine environments. These findings bear implications not only for our understanding of symbiotic relationships in the marine realm but also for the functioning of benthic ecosystems at large. Video Abstract.
Collapse
Affiliation(s)
- Tina Keller-Costa
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Lydia Kozma
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- École Polytechnique Fédérale de Lausanne, Écublens, Switzerland
| | - Sandra G. Silva
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Rodolfo Toscan
- Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Jorge Gonçalves
- Centro de Ciências Do Mar, Universidade Do Algarve, Faro, Portugal
| | - Asunción Lago-Lestón
- Centro de Investigación Científica Y de Educación Superior de Ensenada, Ensenada, Mexico
| | - Nikos C. Kyrpides
- Department of Energy, Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | | | - Rodrigo Costa
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
- Centro de Ciências Do Mar, Universidade Do Algarve, Faro, Portugal
| |
Collapse
|
11
|
Yang Y, Fang A, Feng K, Zhang D, Zhou H, Xing D. Single-cell metagenomics and metagenomics approaches reveal extracellular electron transfer of psychrophilic electroactive biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 836:155606. [PMID: 35504378 DOI: 10.1016/j.scitotenv.2022.155606] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/12/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Abstract
Revealing the metabolic functions and the extracellular electron transfer (EET) process of psychrophilic electroactive biofilms (PEB) is important for understanding the functional adaptability of electroactive bacteria (EAB) to low temperatures. In this study, single cell sorting (SCS)-based metagenomics sequencing was used to characterize the composition and function of the PEB. Biofilm microbiome analysis showed that Geobacter, with a relative abundance of 62.64%, dominated the PEB enriched in the bioelectrochemical system (BES) at 4 °C. Both the metagenome (MAG) and single-cell metagenome (SCM) revealed that there were no obvious metabolic differences between the original biofilm and the sorted single cells. The presence of genes associated with type IV pilus, c-type cytochromes, and riboflavin indicated that the EET potential was maintained in the PEB at low temperatures. These results suggested that SCM provides an alternative approach to reconstruct the metabolic functions of uncultured and slow-growing EAB.
Collapse
Affiliation(s)
- Yang Yang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Heilongjiang Province Key Laboratory of Environmental Biotechnology, Harbin Institute of Technology, Harbin 150090, China
| | - Anran Fang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Kun Feng
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Dawei Zhang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Huihui Zhou
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Heilongjiang Province Key Laboratory of Environmental Biotechnology, Harbin Institute of Technology, Harbin 150090, China
| | - Defeng Xing
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Heilongjiang Province Key Laboratory of Environmental Biotechnology, Harbin Institute of Technology, Harbin 150090, China.
| |
Collapse
|
12
|
Thapa BS, Kim T, Pandit S, Song YE, Afsharian YP, Rahimnejad M, Kim JR, Oh SE. Overview of electroactive microorganisms and electron transfer mechanisms in microbial electrochemistry. BIORESOURCE TECHNOLOGY 2022; 347:126579. [PMID: 34921921 DOI: 10.1016/j.biortech.2021.126579] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Electroactive microorganisms acting as microbial electrocatalysts have intrinsic metabolisms that mediate a redox potential difference between solid electrodes and microbes, leading to spontaneous electron transfer to the electrode (exo-electron transfer) or electron uptake from the electrode (endo-electron transfer). These microbes biochemically convert various organic and/or inorganic compounds to electricity and/or biochemicals in bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs) and microbial electrosynthesis cells (MECs). For the past two decades, intense studies have converged to clarify electron transfer mechanisms of electroactive microbes in BESs, which thereby have led to improved bioelectrochemical performance. Also, many novel exoelectrogenic eukaryotes as well as prokaryotes with electroactive properties are being continuously discovered. This review presents an overview of electroactive microorganisms (bacteria, microalgae and fungi) and their exo- and endo-electron transfer mechanisms in BESs for optimizing and advancing bioelectrochemical techniques.
Collapse
Affiliation(s)
- Bhim Sen Thapa
- Department of Biological Environment, Kangwon National University, Chuncheon, Gangwondo 24341, Republic of Korea
| | - Taeyoung Kim
- Department of Environmental Engineering, Chosun University, Gwangju 61452, Republic of Korea
| | - Soumya Pandit
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida 201306, India
| | - Young Eun Song
- Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA
| | - Yasamin Pesaran Afsharian
- Biofuel and Renewable Energy Research Center, Chemical Engineering Department, Babol Noshirvani University of Technology, Babol, Iran
| | - Mostafa Rahimnejad
- Biofuel and Renewable Energy Research Center, Chemical Engineering Department, Babol Noshirvani University of Technology, Babol, Iran
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Sang-Eun Oh
- Department of Biological Environment, Kangwon National University, Chuncheon, Gangwondo 24341, Republic of Korea.
| |
Collapse
|
13
|
Wu T, Gagnon A, McGourty K, DosSantos R, Chanetsa L, Zhang B, Bello D, Kelleher SL. Zinc Exposure Promotes Commensal-to-Pathogen Transition in Pseudomonas aeruginosa Leading to Mucosal Inflammation and Illness in Mice. Int J Mol Sci 2021; 22:ijms222413321. [PMID: 34948118 PMCID: PMC8705841 DOI: 10.3390/ijms222413321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/02/2021] [Accepted: 12/09/2021] [Indexed: 12/31/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa) is associated gastrointestinal (GI) inflammation and illness; however, factors motivating commensal-to-pathogen transition are unclear. Excessive zinc intake from supplements is common in humans. Due to the fact that zinc exposure enhances P. aeruginosa colonization in vitro, we hypothesized zinc exposure broadly activates virulence mechanisms, leading to inflammation and illness. P. aeruginosa was treated with excess zinc and growth, expression and secretion of key virulence factors, and biofilm production were determined. Effects on invasion, barrier function, and cytotoxicity were evaluated in Caco-2 cells co-cultured with P. aeruginosa pre-treated with zinc. Effects on colonization, mucosal pathology, inflammation, and illness were evaluated in mice infected with P. aeruginosa pre-treated with zinc. We found the expression and secretion of key virulence factors involved in quorum sensing (QS), motility (type IV pili, flagella), biosurfactants (rhamnolipids), toxins (exotoxin A), zinc homeostasis (CzcR), and biofilm production, were all significantly increased. Zinc exposure significantly increased P. aeruginosa invasion, permeability and cytotoxicity in Caco-2 cells, and enhanced colonization, inflammation, mucosal damage, and illness in mice. Excess zinc exposure has broad effects on key virulence mechanisms promoting commensal-to-pathogen transition of P. aeruginosa and illness in mice, suggesting excess zinc intake may have adverse effects on GI health in humans.
Collapse
|
14
|
Packiavathy IASV, Kannappan A, Thiyagarajan S, Srinivasan R, Jeyapragash D, Paul JBJ, Velmurugan P, Ravi AV. AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens. Front Microbiol 2021; 12:634593. [PMID: 33935995 PMCID: PMC8079732 DOI: 10.3389/fmicb.2021.634593] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/15/2021] [Indexed: 11/13/2022] Open
Abstract
Quorum sensing (QS) is a signaling mechanism governed by bacteria used to converse at inter- and intra-species levels through small self-produced chemicals called N-acylhomoserine lactones (AHLs). Through QS, bacteria regulate and organize the virulence factors’ production, including biofilm formation. AHLs can be degraded by an action called quorum quenching (QQ) and hence QQ strategy can effectively be employed to combat biofilm-associated bacterial pathogenesis. The present study aimed to identify novel bacterial species with QQ potential. Screening of Palk Bay marine sediment bacteria for QQ activity ended up with the identification of marine bacterial isolate 28 (MSB-28), which exhibited a profound QQ activity against QS biomarker strain Chromobacterium violaceum ATCC 12472. The isolate MSB-28 was identified as Psychrobacter sp. through 16S-rRNA sequencing. Psychrobacter sp. also demonstrated a pronounced activity in controlling the biofilm formation in different bacteria and biofilm-associated virulence factors’ production in P. aeruginosa PAO1. Solvent extraction, heat inactivation, and proteinase K treatment assays clearly evidence the enzymatic nature of the bioactive lead. Furthermore, AHL’s lactone ring cleavage was confirmed with experiments including ring closure assay and chromatographic analysis, and thus the AHL-lactonase enzyme production in Psychrobacter sp. To conclude, this is the first report stating the AHL-lactonase mediated QQ activity from marine sediment bacteria Psychrobacter sp. Future work deals with the characterization, purification, and mass cultivation of the purified protein and should pave the way to assessing the feasibility of the identified protein in controlling QS and biofilm-mediated multidrug resistant bacterial infections in mono or multi-species conditions.
Collapse
Affiliation(s)
| | - Arunachalam Kannappan
- Department of Biotechnology, Alagappa University, Karaikudi, India.,Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | | | - Ramanathan Srinivasan
- Department of Biotechnology, Alagappa University, Karaikudi, India.,Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Danaraj Jeyapragash
- Department of Biotechnology, Karpagam Academy of Higher Education, Coimbatore, India
| | - John Bosco John Paul
- Department of Electronics and Communication Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India
| | - Pazhanivel Velmurugan
- Department of Biotechnology, Alagappa University, Karaikudi, India.,Centre for Materials Engineering and Regnerative Medicine, Bharath Institute of Higher Education and Research, Chennai, India
| | | |
Collapse
|
15
|
Yang Y, Fang A, Feng K, Liu B, Xie G, Li H, Xing D. Mini-metagenome analysis of psychrophilic electroactive biofilms based on single cell sorting. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:144328. [PMID: 33360470 DOI: 10.1016/j.scitotenv.2020.144328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/22/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
Understanding the metabolic function of psychrophilic electroactive bacteria is important for the investigation of extracellular electron transfer (EET) mechanisms under low temperatures (4-15 °C). In this study, Raman activated cell ejection coupled high throughput sequencing was used to accurately generate a mini-metagenome of psychrophilic bacterial community. Hierarchical cluster analysis of the Raman spectrum could accurately select the target Geobacter cluster. The high relative abundance of the membrane transport functional genes ftsEX in the biofilm community indicated an adaptation to reduced temperature, which aided survival of the electroactive bacteria under low temperature. The basal metabolism such as citrate cycle and glycolytic pathway maintained the electron pool for the EET process. The identification of iron (III) transport system genes in high abundance indicated their presence in an active metabolic reaction for potential electron transfer process. It showed the potential involvement c-type cytochromes (coxA and cox1) activity in EET. These results indicated that psychrophilic Geobacter had effective EET mediated by c-type cytochromes at low temperatures.
Collapse
Affiliation(s)
- Yang Yang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Anran Fang
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Kun Feng
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bingfeng Liu
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guojun Xie
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hang Li
- HOOKE Instruments Ltd., 130033 Changchun, China
| | - Defeng Xing
- School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China.
| |
Collapse
|
16
|
Abstract
The bacterial type IV pilus (T4P) is a prominent virulence factor in many significant human pathogens, some of which have become increasingly antibiotic resistant. Antivirulence chemotherapeutics are considered a promising alternative to antibiotics because they target the disease process instead of bacterial viability. However, a roadblock to the discovery of anti-T4P compounds is the lack of a high-throughput screen (HTS) that can be implemented relatively easily and economically. Here, we describe the first HTS for the identification of inhibitors specifically against the T4P assembly ATPase PilB in vitro. Chloracidobacterium thermophilum PilB (CtPilB) had been demonstrated to have robust ATPase activity and the ability to bind its expected ligands in vitro. We utilized CtPilB and MANT-ATP, a fluorescent ATP analog, to develop a binding assay and adapted it for an HTS. As a proof of principle, we performed a pilot screen with a small compound library of kinase inhibitors and identified quercetin as a PilB inhibitor in vitro. Using Myxococcus xanthus as a model bacterium, we found quercetin to reduce its T4P-dependent motility and T4P assembly in vivo. These results validated our HTS as effective in identifying PilB inhibitors. This assay may prove valuable in seeking leads for the development of antivirulence chemotherapeutics against PilB, an essential and universal component of all bacterial T4P systems. IMPORTANCE Many bacterial pathogens use their type IV pili (T4P) to facilitate and maintain infection of a human host. Small chemical compounds that inhibit the production or assembly of T4P hold promise in the treatment and prevention of infections, especially in the era of increasing threats from antibiotic-resistant bacteria. However, few chemicals are known to have inhibitory or anti-T4P activity. Their identification has not been easy due to the lack of a method for the screening of compound collections or libraries on a large scale. Here, we report the development of an assay that can be scaled up to screen compound libraries for inhibitors of a critical T4P assembly protein. We further demonstrate that it is feasible to use whole cells to examine potential inhibitors for their activity against T4P assembly in a bacterium.
Collapse
|
17
|
Cyclic-di-GMP and ADP bind to separate domains of PilB as mutual allosteric effectors. Biochem J 2020; 477:213-226. [PMID: 31868878 PMCID: PMC6957770 DOI: 10.1042/bcj20190809] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 01/12/2023]
Abstract
PilB is the assembly ATPase for the bacterial type IV pilus (T4P), and as a consequence, it is essential for T4P-mediated bacterial motility. In some cases, PilB has been demonstrated to regulate the production of exopolysaccharide (EPS) during bacterial biofilm development independently of or in addition to its function in pilus assembly. While the ATPase activity of PilB resides at its C-terminal region, the N terminus of a subset of PilBs forms a novel cyclic-di-GMP (cdG)-binding domain. This multi-domain structure suggests that PilB binds cdG and adenine nucleotides through separate domains which may influence the functionality of PilB in both motility and biofilm development. Here, Chloracidobacterium thermophilum PilB is used to investigate ligand binding by its separate domains and by the full-length protein. Our results confirm the specificity of these individual domains for their respective ligands and demonstrate communications between these domains in the full-length protein. It is clear that when the N- and the C-terminal domains of PilB bind to cdG and ADP, respectively, they mutually influence each other in conformation and in their binding to ligands. We propose that the interactions between these domains in response to their ligands play critical roles in modulating or controlling the functions of PilB as a regulator of EPS production and as the T4P assembly ATPase.
Collapse
|
18
|
Thapa BS, Chandra TS. Studies on expression levels of pil Q and fli P genes during bio-electrogenic process in Kluyvera georgiana MCC 3673. 3 Biotech 2020; 10:73. [PMID: 32051806 DOI: 10.1007/s13205-020-2050-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/02/2020] [Indexed: 10/25/2022] Open
Abstract
The bacterium Kluyvera georgiana MCC 3673 transfers electrons directly to the electrode for bio-electricity generation in microbial fuel cell (MFC). This could be due to the formation of biofilm on the surface of electrode or with through the extracellular appendages, or both. The role of extracellular appendages pili and flagella in exo-electron transfer mechanism was investigated. The expression level of the genes fli P and pil Q for pili and flagella, respectively, in K. georgiana MCC 3673 was compared in MFC and in shake flask. The transcript analysis was done by qRT-PCR at different times and conditions. The expression level of pil Q transcript in K. georgiana MCC 3673 showed over twofold higher expression during bio-electrogenic process, compared to the one inoculated in shake flask. Similarly, fli P had also showed similar kind of expression in MFC compared to that in shake flask. Higher level of pil Q and fli P transcripts were observed throughout bio-electrogenic process. The level of pil Q was found to be nearly fourfold higher in biofilm-forming cells forming compared to the cells in suspension form. The obtained results suggest that flagella have a role in movement of bacterium towards electrode for donating the electron in absence of oxygen, and pili aiding in adhering on the surface of electrode and forming biofilm. The cumulative effect of fli P and pil Q resulted in exo-electron transfer to the electrode and bio-electricity generation process. The open circuit potential (OCV) of + 0.7 V was produced with the maximum power density of 393 ± 14 mW/m2 in MFC.
Collapse
|
19
|
How does electron transfer occur in microbial fuel cells? World J Microbiol Biotechnol 2020; 36:19. [PMID: 31955250 DOI: 10.1007/s11274-020-2801-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/08/2020] [Indexed: 12/16/2022]
Abstract
Microbial fuel cells (MFCs) have emerged as a promising technology for sustainable wastewater treatment coupled with electricity generation. A MFC is a device that uses microbes as catalysts to convert chemical energy present in biomass into electrical energy. Among the various mechanisms that drive the operation of a MFC, extracellular electron transfer (EET) to the anode is one of the most important. Exoelectrogenic bacteria can natively transfer electrons to a conducting surface like the anode. The mechanisms employed for electron transfer can either be direct transfer via conductive pili or nanowires, or mediated transfer that involves either naturally secreted redox mediators like flavins and pyocyanins or artificially added mediators like methylene blue and neutral red. EET is a mechanism wherein microorganisms extract energy for growth and maintenance from their surroundings and transfer the resulting electrons to the anode to generate current. The efficiency of these electron transfer mechanisms is dependent not only on the redox potentials of the species involved, but also on microbial oxidative metabolism that liberates electrons. Attempts at understanding the electron transfer mechanisms will boost efforts in giving rise to practical applications. This article covers the various electron transfer mechanisms involved between microbes and electrodes in microbial fuel cells and their applications.
Collapse
|
20
|
Molina L, Segura A, Duque E, Ramos JL. The versatility of Pseudomonas putida in the rhizosphere environment. ADVANCES IN APPLIED MICROBIOLOGY 2019; 110:149-180. [PMID: 32386604 DOI: 10.1016/bs.aambs.2019.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This article addresses the lifestyle of Pseudomonas and focuses on how Pseudomonas putida can be used as a model system for biotechnological processes in agriculture, and in the removal of pollutants from soils. In this chapter we aim to show how a deep analysis using genetic information and experimental tests has helped to reveal insights into the lifestyle of Pseudomonads. Pseudomonas putida is a Plant Growth Promoting Rhizobacteria (PGPR) that establishes commensal relationships with plants. The interaction involves a series of functions encoded by core genes which favor nutrient mobilization, prevention of pathogen development and efficient niche colonization. Certain Pseudomonas putida strains harbor accessory genes that confer specific biodegradative properties and because these microorganisms can thrive on the roots of plants they can be exploited to remove pollutants via rhizoremediation, making the consortium plant/Pseudomonas a useful tool to combat pollution.
Collapse
Affiliation(s)
- Lázaro Molina
- CSIC- Estación Experimental del Zaidín, Granada, Spain
| | - Ana Segura
- CSIC- Estación Experimental del Zaidín, Granada, Spain
| | | | | |
Collapse
|
21
|
Streptomycin mediated biofilm inhibition and suppression of virulence properties in Pseudomonas aeruginosa PAO1. Appl Microbiol Biotechnol 2019; 104:799-816. [PMID: 31820066 DOI: 10.1007/s00253-019-10190-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/09/2019] [Accepted: 10/07/2019] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa is known as an opportunistic pathogen whose one of the antibiotic resistance mechanisms includes biofilm formation and virulence factor production. The present study showed that the sub-minimum inhibitory concentration (sub-MIC) of streptomycin inhibited the formation of biofilm and eradicated the established mature biofilm. Streptomycin at sub-MIC was also capable of inhibiting biofilm formation on the urinary catheters. In addition, the sub-MIC of streptomycin attenuated the bacterial virulence properties as confirmed by both phenotypic and gene expression studies. The optimal conditions for streptomycin to perform anti-biofilm and anti-virulence activities were proposed as alkaline TSB media (pH 7.9) at 35 °C. However, sub-MIC of streptomycin also exhibited a comparative anti-biofilm efficacy in LB media at similar pH level and temperature. Furthermore, this condition also improved the biofilm inhibition and eradication properties of streptomycin, tobramycin and tetracycline towards the biofilm formed by a clinical isolate of P. aeruginosa. Findings from the present study provide an important insight for further studies on the mechanisms of biofilm inhibition and dispersion of pre-existing biofilm by streptomycin as well as tobramycin and tetracycline under a specific culture environment.
Collapse
|
22
|
Bhat AH, Maity S, Giri K, Ambatipudi K. Protein glycosylation: Sweet or bitter for bacterial pathogens? Crit Rev Microbiol 2019; 45:82-102. [PMID: 30632429 DOI: 10.1080/1040841x.2018.1547681] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Protein glycosylation systems in many bacteria are often associated with crucial biological processes like pathogenicity, immune evasion and host-pathogen interactions, implying the significance of protein-glycan linkage. Similarly, host protein glycosylation has been implicated in antimicrobial activity as well as in promoting growth of beneficial strains. In fact, few pathogens notably modulate host glycosylation machineries to facilitate their survival. To date, diverse chemical and biological strategies have been developed for conjugate vaccine production for disease control. Bioconjugate vaccines, largely being produced by glycoengineering using PglB (the N-oligosaccharyltransferase from Campylobacter jejuni) in suitable bacterial hosts, have been highly promising with respect to their effectiveness in providing protective immunity and ease of production. Recently, a novel method of glycoconjugate vaccine production involving an O-oligosaccharyltransferase, PglL from Neisseria meningitidis, has been optimized. Nevertheless, many questions on defining antigenic determinants, glycosylation markers, species-specific differences in glycosylation machineries, etc. still remain unanswered, necessitating further exploration of the glycosylation systems of important pathogens. Hence, in this review, we will discuss the impact of bacterial protein glycosylation on its pathogenesis and the interaction of pathogens with host protein glycosylation, followed by a discussion on strategies used for bioconjugate vaccine development.
Collapse
Affiliation(s)
- Aadil Hussain Bhat
- a Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee , Uttarakhand 247667 , India
| | - Sudipa Maity
- a Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee , Uttarakhand 247667 , India
| | - Kuldeep Giri
- a Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee , Uttarakhand 247667 , India
| | - Kiran Ambatipudi
- a Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee , Uttarakhand 247667 , India
| |
Collapse
|
23
|
Wrobel A, Ottoni C, Leo JC, Linke D. pYR4 From a Norwegian Isolate of Yersinia ruckeri Is a Putative Virulence Plasmid Encoding Both a Type IV Pilus and a Type IV Secretion System. Front Cell Infect Microbiol 2018; 8:373. [PMID: 30460204 PMCID: PMC6232867 DOI: 10.3389/fcimb.2018.00373] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/04/2018] [Indexed: 01/14/2023] Open
Abstract
Enteric redmouth disease caused by the pathogen Yersinia ruckeri is a significant problem for fish farming around the world. Despite its importance, only a few virulence factors of Y. ruckeri have been identified and studied in detail. Here, we report and analyze the complete DNA sequence of pYR4, a plasmid from a highly pathogenic Norwegian Y. ruckeri isolate, sequenced using PacBio SMRT technology. Like the well-known pYV plasmid of human pathogenic Yersiniae, pYR4 is a member of the IncFII family. Thirty-one percent of the pYR4 sequence is unique compared to other Y. ruckeri plasmids. The unique regions contain, among others genes, a large number of mobile genetic elements and two partitioning systems. The G+C content of pYR4 is higher than that of the Y. ruckeri NVH_3758 genome, indicating its relatively recent horizontal acquisition. pYR4, as well as the related plasmid pYR3, comprises operons that encode for type IV pili and for a conjugation system (tra). In contrast to other Yersinia plasmids, pYR4 cannot be cured at elevated temperatures. Our study highlights the power of PacBio sequencing technology for identifying mis-assembled segments of genomic sequences. Comparative analysis of pYR4 and other Y. ruckeri plasmids and genomes, which were sequenced by second and the third generation sequencing technologies, showed errors in second generation sequencing assemblies. Specifically, in the Y. ruckeri 150 and Y. ruckeri ATCC29473 genome assemblies, we mapped the entire pYR3 plasmid sequence. Placing plasmid sequences on the chromosome can result in erroneous biological conclusions. Thus, PacBio sequencing or similar long-read methods should always be preferred for de novo genome sequencing. As the tra operons of pYR3, although misplaced on the chromosome during the genome assembly process, were demonstrated to have an effect on virulence, and type IV pili are virulence factors in many bacteria, we suggest that pYR4 directly contributes to Y. ruckeri virulence.
Collapse
Affiliation(s)
| | - Claudio Ottoni
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Jack C Leo
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| |
Collapse
|
24
|
Lessen HJ, Fleming PJ, Fleming KG, Sodt AJ. Building Blocks of the Outer Membrane: Calculating a General Elastic Energy Model for β-Barrel Membrane Proteins. J Chem Theory Comput 2018; 14:4487-4497. [PMID: 29979594 PMCID: PMC6191857 DOI: 10.1021/acs.jctc.8b00377] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The outer membranes of Gram negative bacteria are the first points of contact these organisms make with their environment. Understanding how composition determines the mechanical properties of this essential barrier is of paramount importance. Therefore, we developed a new computational method to measure the elasticity of transmembrane proteins found in the outer membrane. Using all-atom molecular dynamics simulations of these proteins, we apply a set of external forces to mechanically stress the transmembrane β-barrels. Our results from four representative β-barrels show that outer membrane proteins display elastic properties that are approximately 70 to 190 times stiffer than neat lipid membranes. These findings suggest that outer membrane β-barrels are a significant source of mechanical stability in bacteria. Our all-atom approach further reveals that resistance to radial stress is encoded by a general mechanism that includes stretching of backbone hydrogen bonds and tilting of β-strands with respect to the bilayer normal. This computational framework facilitates an increased theoretical understanding of how varying lipid and protein amounts affect the mechanical properties of the bacterial outer membrane.
Collapse
Affiliation(s)
- Henry J. Lessen
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Patrick J. Fleming
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Karen G. Fleming
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Alexander J. Sodt
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| |
Collapse
|
25
|
Pratama AA, Haq IU, Nazir R, Chaib De Mares M, van Elsas JD. Draft genome sequences of three fungal-interactive Paraburkholderia terrae strains, BS007, BS110 and BS437. Stand Genomic Sci 2017; 12:81. [PMID: 29270249 PMCID: PMC5735546 DOI: 10.1186/s40793-017-0293-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 11/24/2017] [Indexed: 02/08/2023] Open
Abstract
Here, we report the draft genome sequences of three fungal-interactive 10.1601/nm.27008 strains, denoted BS110, BS007 and BS437. Phylogenetic analyses showed that the three strains belong to clade II of the genus 10.1601/nm.1619, which was recently renamed 10.1601/nm.26956. This novel genus primarily contains environmental species, encompassing non-pathogenic plant- as well as fungal-interactive species. The genome of strain BS007 consists of 11,025,273 bp, whereas those of strains BS110 and BS437 have 11,178,081 and 11,303,071 bp, respectively. Analyses of the three annotated genomes revealed the presence of (1) a large suite of substrate capture systems, and (2) a suite of genetic systems required for adaptation to microenvironments in soil and the mycosphere. Thus, genes encoding traits that potentially confer fungal interactivity were found, such as type 4 pili, type 1, 2, 3, 4 and 6 secretion systems, and biofilm formation (PGA, alginate and pel) and glycerol uptake systems. Furthermore, the three genomes also revealed the presence of a highly conserved five-gene cluster that had previously been shown to be upregulated upon contact with fungal hyphae. Moreover, a considerable number of prophage-like and CRISPR spacer sequences was found, next to genetic systems responsible for secondary metabolite production. Overall, the three 10.1601/nm.27008 strains possess the genetic repertoire necessary for adaptation to diverse soil niches, including those influenced by soil fungi.
Collapse
Affiliation(s)
- Akbar Adjie Pratama
- Department of Microbial Ecology, Microbial Ecology - Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747 AG The Netherlands
| | - Irshad Ul Haq
- Department of Microbial Ecology, Microbial Ecology - Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747 AG The Netherlands
| | - Rashid Nazir
- Department of Environmental Sciences COMSATS Institute of Information Technology, University Road, Abbottabad, 22060 Pakistan
| | - Maryam Chaib De Mares
- Department of Microbial Ecology, Microbial Ecology - Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747 AG The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Microbial Ecology - Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen, 9747 AG The Netherlands
| |
Collapse
|
26
|
Electron microscopic observations of prokaryotic surface appendages. J Microbiol 2017; 55:919-926. [DOI: 10.1007/s12275-017-7369-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/10/2017] [Accepted: 10/15/2017] [Indexed: 12/21/2022]
|
27
|
de Haan HW. Modeling and Simulating the Dynamics of Type IV Pili Extension of Pseudomonas aeruginosa. Biophys J 2017; 111:2263-2273. [PMID: 27851948 DOI: 10.1016/j.bpj.2016.09.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/13/2016] [Accepted: 09/29/2016] [Indexed: 01/10/2023] Open
Abstract
Bacteria such as Pseudomonas aeruginosa use type IV pili to move across surfaces. The pili extend, attach to the surface, and then retract to move the bacteria forward. In this article, a coarse-grained model of pilus extension and attachment is developed. Simulations performed at biologically relevant conditions indicate that pilus extension is a quasistatic process such that the pili are able to relax via thermal fluctuations as it is being built and extended. Results are generated for pili with different rigidities ranging from very flexible to very stiff. It is shown that very flexible pili do not extend very far and thus would limit the bacteria to short jumps forward while stiff pili enable much greater displacements. Feasible mechanisms of attachment to the surface are also found to vary greatly between flexible and stiff pili. While it is not always the tip of flexible pili that first makes contact with the substrate, it is likely to be a part of the pili that is close to the tip. Conversely, stiff pili are much more likely to make contact with the substrate via the tip, but if not then the part of the pilus that attaches can be quite far from the tip. These results thus give insight to help resolve current discrepancies in the literature regarding pilus stiffness and the location of adhesins on pili.
Collapse
Affiliation(s)
- Hendrick W de Haan
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada.
| |
Collapse
|
28
|
Effects of tcpB Mutations on Biogenesis and Function of the Toxin-Coregulated Pilus, the Type IVb Pilus of Vibrio cholerae. J Bacteriol 2016; 198:2818-28. [PMID: 27481929 DOI: 10.1128/jb.00309-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/23/2016] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED Vibrio cholerae is the etiological agent of the acute intestinal disorder cholera. The toxin-coregulated pilus (TCP), a type IVb pilus, is an essential virulence factor of V. cholerae Recent work has shown that TcpB is a large minor pilin encoded within the tcp operon. TcpB contributes to efficient pilus formation and is essential for all TCP functions. Here, we have initiated a detailed targeted mutagenesis approach to further characterize this salient TCP component. We have identified (thus far) 20 residues of TcpB which affect either the steady-state level of TcpB or alter one or more TCP functions. This study provides a solid framework for further understanding of the complex role of TcpB and will be of use upon determination of the crystal structure of TcpB or related minor pilin orthologs of type IVb pilus systems. IMPORTANCE Type IV pili, such as the toxin-coregulated pilus (TCP) in V. cholerae, are bacterial appendages that often act as essential virulence factors. Minor pilins, like TcpB, of these pili systems often play integral roles in pilus assembly and function. In this study, we have generated mutations in tcpB to determine residues of importance for TCP stability and function. Combined with a predicted tertiary structure, characterization of these mutants allows us to better understand critical residues in TcpB and the role they may play in the mechanisms underlying minor pilin functions.
Collapse
|
29
|
Hassan A, Naz A, Obaid A, Paracha RZ, Naz K, Awan FM, Muhmmad SA, Janjua HA, Ahmad J, Ali A. Pangenome and immuno-proteomics analysis of Acinetobacter baumannii strains revealed the core peptide vaccine targets. BMC Genomics 2016; 17:732. [PMID: 27634541 PMCID: PMC5025611 DOI: 10.1186/s12864-016-2951-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/19/2016] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii has emerged as a significant nosocomial pathogen during the last few years, exhibiting resistance to almost all major classes of antibiotics. Alternative treatment options such as vaccines tend to be most promising and cost effective approaches against this resistant pathogen. In the current study, we have explored the pan-genome of A. baumannii followed by immune-proteomics and reverse vaccinology approaches to identify potential core vaccine targets. RESULTS The pan-genome of all available A. baumannii strains (30 complete genomes) is estimated to contain 7,606 gene families and the core genome consists of 2,445 gene families (~32 % of the pan-genome). Phylogenetic tree, comparative genomic and proteomic analysis revealed both intra- and inter genomic similarities and evolutionary relationships. Among the conserved core genome, thirteen proteins, including P pilus assembly protein, pili assembly chaperone, AdeK, PonA, OmpA, general secretion pathway protein D, FhuE receptor, Type VI secretion system OmpA/MotB, TonB dependent siderophore receptor, general secretion pathway protein D, outer membrane protein, peptidoglycan associated lipoprotein and peptidyl-prolyl cis-trans isomerase are identified as highly antigenic. Epitope mapping of the target proteins revealed the presence of antigenic surface exposed 9-mer T-cell epitopes. Protein-protein interaction and functional annotation have shown their involvement in significant biological and molecular processes. The pipeline is validated by predicting already known immunogenic targets against Gram negative pathogen Helicobacter pylori as a positive control. CONCLUSION The study, based upon combinatorial approach of pan-genomics, core genomics, proteomics and reverse vaccinology led us to find out potential vaccine candidates against A. baumannii. The comprehensive analysis of all the completely sequenced genomes revealed thirteen putative antigens which could elicit substantial immune response. The integration of computational vaccinology strategies would facilitate in tackling the rapid dissemination of resistant A.baumannii strains. The scarcity of effective antibiotics and the global expansion of sequencing data making this approach desirable in the development of effective vaccines against A. baumannii and other bacterial pathogens.
Collapse
Affiliation(s)
- Afreenish Hassan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Anam Naz
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Ayesha Obaid
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Rehan Zafar Paracha
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Kanwal Naz
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Faryal Mehwish Awan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Syed Aun Muhmmad
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Hussnain Ahmed Janjua
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Jamil Ahmad
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
- Department of Computer Science and Information Technology, Stratford University, Falls Church, VA 22043 USA
| | - Amjad Ali
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| |
Collapse
|
30
|
Hariri BM, Payne SJ, Chen B, Mansfield C, Doghramji LJ, Adappa ND, Palmer JN, Kennedy DW, Niv MY, Lee RJ. In vitro effects of anthocyanidins on sinonasal epithelial nitric oxide production and bacterial physiology. Am J Rhinol Allergy 2016; 30:261-8. [PMID: 27456596 PMCID: PMC4953345 DOI: 10.2500/ajra.2016.30.4331] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND T2R bitter taste receptors play a crucial role in sinonasal innate immunity by upregulating mucociliary clearance and nitric oxide (NO) production in response to bitter gram-negative quorum-sensing molecules in the airway surface liquid. Previous studies showed that phytochemical flavonoid metabolites, known as anthocyanidins, taste bitter and have antibacterial effects. Our objectives were to examine the effects of anthocyanidins on NO production by human sinonasal epithelial cells and ciliary beat frequency, and their impact on common sinonasal pathogens Pseudomonas aeruginosa and Staphylococcus aureus. METHODS Ciliary beat frequency and NO production were measured by using digital imaging of differentiated air-liquid interface cultures prepared from primary human cells isolated from residual surgical material. Plate-based assays were used to determine the effects of anthocyanidins on bacterial swimming and swarming motility. Biofilm formation and planktonic growth were also assessed. RESULTS Anthocyanidin compounds triggered epithelial cells to produce NO but not through T2R receptors. However, anthocyanidins did not impact ciliary beat frequency. Furthermore, they did not reduce biofilm formation or planktonic growth of P. aeruginosa. In S. aureus, they did not reduce planktonic growth, and only one compound had minimal antibiofilm effects. The anthocyanidin delphinidin and anthocyanin keracyanin were found to promote bacterial swimming, whereas anthocyanidin cyanidin and flavonoid myricetin did not. No compounds that were tested inhibited bacterial swarming. CONCLUSION Results of this study indicated that, although anthocyanidins may elicited an innate immune NO response from human cells, they do not cause an increase in ciliary beating and they may also cause a pathogenicity-enhancing effect in P. aeruginosa. Additional studies are necessary to understand how this would affect the use of anthocyanidins as therapeutics. This study emphasized the usefulness of in vitro screening of candidate compounds against multiple parameters of both epithelial and bacterial physiologies to prioritize candidates for in vivo therapeutic testing.
Collapse
Affiliation(s)
- Benjamin M. Hariri
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Sakeena J. Payne
- Division of Otolaryngology, Department of Surgery, Pennsylvania State University Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Bei Chen
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | | | - Laurel J. Doghramji
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Nithin D. Adappa
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - James N. Palmer
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - David W. Kennedy
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Masha Y. Niv
- The Institute of Biochemistry, Food and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Israel, and
| | - Robert J. Lee
- From the Department of Otorhinolaryngology—Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|
31
|
Qi W, Vaughan L, Katharios P, Schlapbach R, Seth-Smith HMB. Host-Associated Genomic Features of the Novel Uncultured Intracellular Pathogen Ca. Ichthyocystis Revealed by Direct Sequencing of Epitheliocysts. Genome Biol Evol 2016; 8:1672-89. [PMID: 27190004 PMCID: PMC4943182 DOI: 10.1093/gbe/evw111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2016] [Indexed: 12/24/2022] Open
Abstract
Advances in single-cell and mini-metagenome sequencing have enabled important investigations into uncultured bacteria. In this study, we applied the mini-metagenome sequencing method to assemble genome drafts of the uncultured causative agents of epitheliocystis, an emerging infectious disease in the Mediterranean aquaculture species gilthead seabream. We sequenced multiple cyst samples and constructed 11 genome drafts from a novel beta-proteobacterial lineage, Candidatus Ichthyocystis. The draft genomes demonstrate features typical of pathogenic bacteria with an obligate intracellular lifestyle: a reduced genome of up to 2.6 Mb, reduced G + C content, and reduced metabolic capacity. Reconstruction of metabolic pathways reveals that Ca Ichthyocystis genomes lack all amino acid synthesis pathways, compelling them to scavenge from the fish host. All genomes encode type II, III, and IV secretion systems, a large repertoire of predicted effectors, and a type IV pilus. These are all considered to be virulence factors, required for adherence, invasion, and host manipulation. However, no evidence of lipopolysaccharide synthesis could be found. Beyond the core functions shared within the genus, alignments showed distinction into different species, characterized by alternative large gene families. These comprise up to a third of each genome, appear to have arisen through duplication and diversification, encode many effector proteins, and are seemingly critical for virulence. Thus, Ca Ichthyocystis represents a novel obligatory intracellular pathogenic beta-proteobacterial lineage. The methods used: mini-metagenome analysis and manual annotation, have generated important insights into the lifestyle and evolution of the novel, uncultured pathogens, elucidating many putative virulence factors including an unprecedented array of novel gene families.
Collapse
Affiliation(s)
- Weihong Qi
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Lloyd Vaughan
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
| | - Pantelis Katharios
- Hellenic Center for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, Heraklion, Greece
| | - Ralph Schlapbach
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Helena M B Seth-Smith
- Functional Genomics Center Zurich, University of Zurich, Switzerland Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
| |
Collapse
|
32
|
Pachiadaki MG, Rédou V, Beaudoin DJ, Burgaud G, Edgcomb VP. Fungal and Prokaryotic Activities in the Marine Subsurface Biosphere at Peru Margin and Canterbury Basin Inferred from RNA-Based Analyses and Microscopy. Front Microbiol 2016; 7:846. [PMID: 27375571 PMCID: PMC4899926 DOI: 10.3389/fmicb.2016.00846] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/22/2016] [Indexed: 11/13/2022] Open
Abstract
The deep sedimentary biosphere, extending 100s of meters below the seafloor harbors unexpected diversity of Bacteria, Archaea, and microbial eukaryotes. Far less is known about microbial eukaryotes in subsurface habitats, albeit several studies have indicated that fungi dominate microbial eukaryotic communities and fungal molecular signatures (of both yeasts and filamentous forms) have been detected in samples as deep as 1740 mbsf. Here, we compare and contrast fungal ribosomal RNA gene signatures and whole community metatranscriptomes present in sediment core samples from 6 and 95 mbsf from Peru Margin site 1229A and from samples from 12 and 345 mbsf from Canterbury Basin site U1352. The metatranscriptome analyses reveal higher relative expression of amino acid and peptide transporters in the less nutrient rich Canterbury Basin sediments compared to the nutrient rich Peru Margin, and higher expression of motility genes in the Peru Margin samples. Higher expression of genes associated with metals transporters and antibiotic resistance and production was detected in Canterbury Basin sediments. A poly-A focused metatranscriptome produced for the Canterbury Basin sample from 345 mbsf provides further evidence for active fungal communities in the subsurface in the form of fungal-associated transcripts for metabolic and cellular processes, cell and membrane functions, and catalytic activities. Fungal communities at comparable depths at the two geographically separated locations appear dominated by distinct taxa. Differences in taxonomic composition and expression of genes associated with particular metabolic activities may be a function of sediment organic content as well as oceanic province. Microscopic analysis of Canterbury Basin sediment samples from 4 and 403 mbsf produced visualizations of septate fungal filaments, branching fungi, conidiogenesis, and spores. These images provide another important line of evidence supporting the occurrence and activity of fungi in the deep subseafloor biosphere.
Collapse
Affiliation(s)
- Maria G Pachiadaki
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Vanessa Rédou
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, EA 3882, ESIAB, Technopôle de Brest Iroise, Université de Brest Plouzané, France
| | - David J Beaudoin
- Department of Biology, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Gaëtan Burgaud
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, EA 3882, ESIAB, Technopôle de Brest Iroise, Université de Brest Plouzané, France
| | - Virginia P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| |
Collapse
|
33
|
Bacteria differently deploy type-IV pili on surfaces to adapt to nutrient availability. NPJ Biofilms Microbiomes 2016; 2:15029. [PMID: 28721239 PMCID: PMC5515259 DOI: 10.1038/npjbiofilms.2015.29] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 11/12/2015] [Accepted: 11/18/2015] [Indexed: 12/27/2022] Open
Abstract
The structure of bacterial biofilms depends on environmental conditions, such as availability of nutrients, during biofilm formation. In turn, variations in biofilm structure in part reflect differences in bacterial motility during early biofilm formation. Pseudomonas aeruginosa deprived of nutrients remain dispersed on a surface, whereas cells supplemented with additional nutrients cluster and form microcolonies. At the single-cell scale, how bacteria modify their motility to favour distinct life cycle outcomes remains poorly understood. High-throughput algorithms were used to track thousands of P. aeruginosa moving using type-IV pili (TFP) on surfaces in varying nutrient conditions and hence identify four distinct motility types. A minimal stochastic model was used to reproduce the TFP-driven motility types. We report that P. aeruginosa cells differently deploy TFP to alter the distribution of motility types under different nutrient conditions. Bacteria preferentially crawl unidirectionally under nutrient-limited conditions, but preferentially stall under nutrient-supplemented conditions. Motility types correlate with subcellular localisation of FimX, a protein required for TFP assembly and implicated in environmental response. The subcellular distribution of FimX is asymmetric for unidirectional crawling, consistent with TFP assembled primarily at the leading pole, whereas for non-translational types FimX expression is symmetric or non-existent. These results are consistent with a minimal stochastic model that reproduces the motility types from the subcellular average concentration and asymmetry of FimX. These findings reveal that P. aeruginosa deploy TFP symmetrically or asymmetrically to modulate motility behaviours in different nutrient conditions and thereby form biofilms only where nutrients are sufficient, which greatly enhances their competitive capacity in diverse environments.
Collapse
|
34
|
Kwak MJ, Kwon SK, Yoon JH, Kim JF. Genome sequence of Lysobacter dokdonensis DS-58(T), a gliding bacterium isolated from soil in Dokdo, Korea. Stand Genomic Sci 2015; 10:123. [PMID: 26664701 PMCID: PMC4673725 DOI: 10.1186/s40793-015-0116-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 11/25/2015] [Indexed: 11/10/2022] Open
Abstract
Lysobacter dokdonensis DS-58, belonging to the family Xanthomonadaceae, was isolated from a soil sample in Dokdo, Korea in 2011. Strain DS-58 is the type strain of L. dokdonensis. In this study, we determined the genome sequence to describe the genomic features including annotation information and COG functional categorization. The draft genome sequence consists of 25 contigs totaling 3,274,406 bp (67.24 % G + C) and contains 3,155 protein coding genes, 2 copies of ribosomal RNA operons, and 48 transfer RNA genes. Among the protein coding genes, 75.91 % of the genes were annotated with a putative function and 87.39 % of the genes were assigned to the COG category. In the genome of L. dokdonensis, a large number of genes associated with protein degradation and antibiotic resistance were detected.
Collapse
Affiliation(s)
- Min-Jung Kwak
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 Republic of Korea
| | - Soon-Kyeong Kwon
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 Republic of Korea
| | - Jung-Hoon Yoon
- Department of Food Science and Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Jihyun F Kim
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 Republic of Korea
| |
Collapse
|
35
|
Stokke R, Dahle H, Roalkvam I, Wissuwa J, Daae FL, Tooming-Klunderud A, Thorseth IH, Pedersen RB, Steen IH. Functional interactions among filamentous Epsilonproteobacteria and Bacteroidetes in a deep-sea hydrothermal vent biofilm. Environ Microbiol 2015; 17:4063-77. [PMID: 26147346 DOI: 10.1111/1462-2920.12970] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/25/2015] [Accepted: 06/25/2015] [Indexed: 11/30/2022]
Abstract
Little is known about how lithoautotrophic primary production is connected to microbial organotrophic consumption in hydrothermal systems. Using a multifaceted approach, we analysed the structure and metabolic capabilities within a biofilm growing on the surface of a black smoker chimney in the Loki's Castle vent field. Imaging revealed the presence of rod-shaped Bacteroidetes growing as ectobionts on long, sheathed microbial filaments (> 100 μm) affiliated with the Sulfurovum genus within Epsilonproteobacteria. The filaments were composed of a thick (> 200 nm) stable polysaccharide, representing a substantial fraction of organic carbon produced by primary production. An integrated -omics approach enabled us to assess the metabolic potential and in situ metabolism of individual taxonomic and morphological groups identified by imaging. Specifically, we provide evidence that organotrophic Bacteroidetes attach to and glide along the surface of Sulfurovum filaments utilizing organic polymers produced by the lithoautotrophic Sulfurovum. Furthermore, in situ expression of acetyl-CoA synthetase by Sulfurovum suggested the ability to assimilate acetate, indicating recycling of organic matter in the biofilm. This study expands our understanding of the lifestyles of Epsilonproteobacteria in hydrothermal vents, their metabolic properties and co-operative interactions in deep-sea hydrothermal vent food webs.
Collapse
Affiliation(s)
- Runar Stokke
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Håkon Dahle
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Irene Roalkvam
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Juliane Wissuwa
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Frida Lise Daae
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Ave Tooming-Klunderud
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Blindernveien 31, 0316, Oslo, Norway
| | - Ingunn H Thorseth
- Centre for Geobiology.,Department of Earth Science, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Rolf B Pedersen
- Centre for Geobiology.,Department of Earth Science, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| | - Ida Helene Steen
- Centre for Geobiology.,Department of Biology, University of Bergen, Allegaten 41, 5020, Bergen, Norway
| |
Collapse
|
36
|
Abstract
Pseudomonads sense changes in the concentration of chemicals in their environment and exhibit a behavioral response mediated by flagella or pili coupled with a chemosensory system. The two known chemotaxis pathways, a flagella-mediated pathway and a putative pili-mediated system, are described in this review. Pseudomonas shows chemotaxis response toward a wide range of chemicals, and this review includes a summary of them organized by chemical structure. The assays used to measure positive and negative chemotaxis swimming and twitching Pseudomonas as well as improvements to those assays and new assays are also described. This review demonstrates that there is ample research and intellectual space for future investigators to elucidate the role of chemotaxis in important processes such as pathogenesis, bioremediation, and the bioprotection of plants and animals.
Collapse
Affiliation(s)
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA, USA
| | - Tino Krell
- Department of Environmental Protection, CSIC, Estacion Experimental del Zaidin, Granada, Spain
| | - Jane E Hill
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| |
Collapse
|
37
|
RNA sequencing analysis of the broad-host-range strain Sinorhizobium fredii NGR234 identifies a large set of genes linked to quorum sensing-dependent regulation in the background of a traI and ngrI deletion mutant. Appl Environ Microbiol 2014; 80:5655-71. [PMID: 25002423 DOI: 10.1128/aem.01835-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The alphaproteobacterium Sinorhizobium fredii NGR234 has an exceptionally wide host range, as it forms nitrogen-fixing nodules with more legumes than any other known microsymbiont. Within its 6.9-Mbp genome, it encodes two N-acyl-homoserine-lactone synthase genes (i.e., traI and ngrI) involved in the biosynthesis of two distinct autoinducer I-type molecules. Here, we report on the construction of an NGR234-ΔtraI and an NGR234-ΔngrI mutant and their genome-wide transcriptome analysis. A high-resolution RNA sequencing (RNA-seq) analysis of early-stationary-phase cultures in the NGR234-ΔtraI background suggested that up to 316 genes were differentially expressed in the NGR234-ΔtraI mutant versus the parent strain. Similarly, in the background of NGR234-ΔngrI 466 differentially regulated genes were identified. Accordingly, a common set of 186 genes was regulated by the TraI/R and NgrI/R regulon. Coregulated genes included 42 flagellar biosynthesis genes and 22 genes linked to exopolysaccharide (EPS) biosynthesis. Among the genes and open reading frames (ORFs) that were differentially regulated in NGR234-ΔtraI were those linked to replication of the pNGR234a symbiotic plasmid and cytochrome c oxidases. Biotin and pyrroloquinoline quinone biosynthesis genes were differentially expressed in the NGR234-ΔngrI mutant as well as the entire cluster of 21 genes linked to assembly of the NGR234 type III secretion system (T3SS-II). Further, we also discovered that genes responsible for rhizopine catabolism in NGR234 were strongly repressed in the presence of high levels of N-acyl-homoserine-lactones. Together with nodulation assays, the RNA-seq-based findings suggested that quorum sensing (QS)-dependent gene regulation appears to be of higher relevance during nonsymbiotic growth rather than for life within root nodules.
Collapse
|
38
|
Genome sequence and phenotypic analysis of a first German Francisella sp. isolate (W12-1067) not belonging to the species Francisella tularensis. BMC Microbiol 2014; 14:169. [PMID: 24961323 PMCID: PMC4230796 DOI: 10.1186/1471-2180-14-169] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/19/2014] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Francisella isolates from patients suffering from tularemia in Germany are generally strains of the species F. tularensis subsp. holarctica. To our knowledge, no other Francisella species are known for Germany. Recently, a new Francisella species could be isolated from a water reservoir of a cooling tower in Germany. RESULTS We identified a Francisella sp. (isolate W12-1067) whose 16S rDNA is 99% identical to the respective nucleotide sequence of the recently published strain F. guangzhouensis. The overall sequence identity of the fopA, gyrA, rpoA, groEL, sdhA and dnaK genes is only 89%, indicating that strain W12-1067 is not identical to F. guangzhouensis. W12-1067 was isolated from a water reservoir of a cooling tower of a hospital in Germany. The growth optimum of the isolate is approximately 30°C, it can grow in the presence of 4-5% NaCl (halotolerant) and is able to grow without additional cysteine within the medium. The strain was able to replicate within a mouse-derived macrophage-like cell line. The whole genome of the strain was sequenced (~1.7 mbp, 32.2% G + C content) and the draft genome was annotated. Various virulence genes common to the genus Francisella are present, but the Francisella pathogenicity island (FPI) is missing. However, another putative type-VI secretion system is present within the genome of strain W12-1067. CONCLUSIONS Isolate W12-1067 is closely related to the recently described F. guangzhouensis species and it replicates within eukaryotic host cells. Since W12-1067 exhibits a putative new type-VI secretion system and F. tularensis subsp. holarctica was found not to be the sole species in Germany, the new isolate is an interesting species to be analyzed in more detail. Further research is needed to investigate the epidemiology, ecology and pathogenicity of Francisella species present in Germany.
Collapse
|
39
|
Bitrian M, González RH, Paris G, Hellingwerf KJ, Nudel CB. Blue-light-dependent inhibition of twitching motility in Acinetobacter baylyi ADP1: additive involvement of three BLUF-domain-containing proteins. Microbiology (Reading) 2013; 159:1828-1841. [DOI: 10.1099/mic.0.069153-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Mariana Bitrian
- Cátedra de Microbiología Industrial y Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Rodrigo H. González
- Cátedra de Microbiología Industrial y Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gaston Paris
- Fundación Instituto Leloir, IIBBA-Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Buenos Aires, Argentina
| | - Klaas J. Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Clara B. Nudel
- Cátedra de Microbiología Industrial y Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| |
Collapse
|
40
|
Li C, Wallace RA, Black WP, Li YZ, Yang Z. Type IV pilus proteins form an integrated structure extending from the cytoplasm to the outer membrane. PLoS One 2013; 8:e70144. [PMID: 23922942 PMCID: PMC3724824 DOI: 10.1371/journal.pone.0070144] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/20/2013] [Indexed: 11/18/2022] Open
Abstract
The bacterial type IV pilus (T4P) is the strongest biological motor known to date as its retraction can generate forces well over 100 pN. Myxococcus xanthus, a δ-proteobacterium, provides a good model for T4P investigations because its social (S) gliding motility is powered by T4P. In this study, the interactions among M. xanthus T4P proteins were investigated using genetics and the yeast two-hybrid (Y2H) system. Our genetic analysis suggests that there is an integrated T4P structure that crosses the inner membrane (IM), periplasm and the outer membrane (OM). Moreover, this structure exists in the absence of the pilus filament. A systematic Y2H survey provided evidence for direct interactions among IM and OM proteins exposed to the periplasm. For example, the IM lipoprotein PilP interacted with its cognate OM protein PilQ. In addition, interactions among T4P proteins from the thermophile Thermus thermophilus were investigated by Y2H. The results indicated similar protein-protein interactions in the T4P system of this non-proteobacterium despite significant sequence divergence between T4P proteins in T. thermophilus and M. xanthus. The observations here support the model of an integrated T4P structure in the absence of a pilus in diverse bacterial species.
Collapse
Affiliation(s)
- Chengyun Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, China
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Regina A. Wallace
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Wesley P. Black
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Yue-zhong Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, China
| | - Zhaomin Yang
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
| |
Collapse
|
41
|
Evolution of Pseudomonas aeruginosa virulence as a result of phage predation. Appl Environ Microbiol 2013; 79:6110-6. [PMID: 23892756 DOI: 10.1128/aem.01421-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rapid increase in the emergence of antibiotic-resistant bacteria has attracted attention to bacteriophages for treating and preventing bacterial infections. Bacteriophages can drive the diversification of Pseudomonas aeruginosa, giving rise to phage-resistant variants with different phenotypes from their ancestral hosts. In this study, we sought to investigate the effect of phage resistance on cytotoxicity of host populations toward cultured mammalian cells. The library of phage-resistant P. aeruginosa PAO1 variants used was developed previously via experimental evolution of an isogenic host population using phages PP7 and E79. Our results presented herein indicate that the phage-resistant variants developed in a heterogeneous phage environment exhibit a greater ability to impede metabolic action of cultured human keratinocytes and have a greater tendency to cause membrane damage even though they cannot invade the cells in large numbers. They also show a heightened resistance to phagocytosis by model murine macrophages. Furthermore, all isolates produced higher levels of at least one of the secreted virulence factors, namely, total proteases, elastase, phospholipase C, and hemolysins. Reverse transcription-quantitative PCR (RT-qPCR) revealed upregulation in the transcription of a number of genes associated with virulence of P. aeruginosa for the phage-resistant variants. The results of this study indicate a significant change in the in vitro virulence of P. aeruginosa following phage predation and highlight the need for caution in the selection and design of phages and phage cocktails for therapeutic use.
Collapse
|
42
|
Streptomycin inhibits quorum sensing in Acinetobacter baumannii. Antimicrob Agents Chemother 2013; 57:1926-9. [PMID: 23318804 DOI: 10.1128/aac.02161-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptomycin at subinhibitory concentrations was found to inhibit quorum sensing in Acinetobacter baumannii. Conditioned medium prepared by growth of A. baumannii in the presence of subinhibitory concentrations of streptomycin exhibited reduced activation of two quorum-sensing-regulated genes, abaI, encoding an autoinducer synthase, and A1S_0112. The reduced expression of AbaI resulted in greatly decreased levels of 3-OH-C(12)-HSL as confirmed by direct analysis using thin-layer chromatography. The effect on acyl-homoserine lactone (AHL) signal production was specific to streptomycin, as gentamicin and myomycin had no significant effect at subinhibitory levels.
Collapse
|
43
|
Affiliation(s)
- Lori L. Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada;
| |
Collapse
|
44
|
Siddaramappa S, Challacombe JF, Petersen JM, Pillai S, Kuske CR. Genetic diversity within the genus Francisella as revealed by comparative analyses of the genomes of two North American isolates from environmental sources. BMC Genomics 2012; 13:422. [PMID: 22920915 PMCID: PMC3479022 DOI: 10.1186/1471-2164-13-422] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 08/14/2012] [Indexed: 12/14/2022] Open
Abstract
Background Francisella tularensis is an intracellular pathogen that causes tularemia in humans and the public health importance of this bacterium has been well documented in recent history. Francisella philomiragia, a distant relative of F. tularensis, is thought to constitute an environmental lineage along with Francisella novicida. Nevertheless, both F. philomiragia and F. novicida have been associated with human disease, primarily in immune-compromised individuals. To understand the genetic relationships and evolutionary contexts among different lineages within the genus Francisella, the genome of Francisella spp. strain TX07-7308 was sequenced and compared to the genomes of F. philomiragia strains ATCC 25017 and 25015, F. novicida strain U112, and F. tularensis strain Schu S4. Results The size of strain ATCC 25017 chromosome was 2,045,775 bp and contained 1,983 protein-coding genes. The size of strain TX07-7308 chromosome was 2,035,931 bp and contained 1,980 protein-coding genes. Pairwise BLAST comparisons indicated that strains TX07-7308 and ATCC 25017 contained 1,700 protein coding genes in common. NUCmer analyses revealed that the chromosomes of strains TX07-7308 and ATCC 25017 were mostly collinear except for a few gaps, translocations, and/or inversions. Using the genome sequence data and comparative analyses with other members of the genus Francisella (e.g., F. novicida strain U112 and F. tularensis strain Schu S4), several strain-specific genes were identified. Strains TX07-7308 and ATCC 25017 contained an operon with six open reading frames encoding proteins related to enzymes involved in thiamine biosynthesis that was absent in F. novicida strain U112 and F. tularensis strain Schu S4. Strain ATCC 25017 contained an operon putatively involved in lactose metabolism that was absent in strain TX07-7308, F. novicida strain U112, and F. tularensis strain Schu S4. In contrast, strain TX07-7308 contained an operon putatively involved in glucuronate metabolism that was absent in the genomes of strain ATCC 25017, F. novicida strain U112, and F. tularensis strain Schu S4. The polymorphic nature of polysaccharide biosynthesis/modification gene clusters among different Francisella strains was also evident from genome analyses. Conclusions From genome comparisons, it appeared that genes encoding novel functions have contributed to the metabolic enrichment of the environmental lineages within the genus Francisella. The inability to acquire new genes coupled with the loss of ancestral traits and the consequent reductive evolution may be a cause for, as well as an effect of, niche selection of F. tularensis. Sequencing and comparison of the genomes of more isolates are required to obtain further insights into the ecology and evolution of different species within the genus Francisella.
Collapse
|
45
|
Wu Y, Jiang Y, Kaiser AD, Alber M. Self-organization in bacterial swarming: lessons from myxobacteria. Phys Biol 2011; 8:055003. [PMID: 21832807 DOI: 10.1088/1478-3975/8/5/055003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
When colonizing surfaces, many bacteria are able to self-organize into an actively expanding biofilm, in which millions of cells move smoothly and orderly at high densities. This phenomenon is known as bacterial swarming. Despite the apparent resemblance to patterns seen in liquid crystals, the dynamics of bacterial swarming cannot be explained by theories derived from equilibrium statistical mechanics. To understand how bacteria swarm, a central question is how order emerges in dense and initially disorganized populations of bacterial cells. Here we briefly review recent efforts, with integrated computational and experimental approaches, in addressing this question.
Collapse
Affiliation(s)
- Yilin Wu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | | | | |
Collapse
|
46
|
Abstract
Bacteria optimize the use of their motility appendages to move efficiently on a wide range of surfaces prior to forming multicellular bacterial biofilms. The "twitching" motility mode employed by many bacterial species for surface exploration uses type-IV pili (TFP) as linear actuators to enable directional crawling. In addition to linear motion, however, motility requires turns and changes of direction. Moreover, the motility mechanism must be adaptable to the continually changing surface conditions encountered during biofilm formation. Here, we develop a novel two-point tracking algorithm to dissect twitching motility in this context. We show that TFP-mediated crawling in Pseudomonas aeruginosa consistently alternates between two distinct actions: a translation of constant velocity and a combined translation-rotation that is approximately 20× faster in instantaneous velocity. Orientational distributions of these actions suggest that the former is due to pulling by multiple TFP, whereas the latter is due to release by single TFP. The release action leads to a fast "slingshot" motion that can turn the cell body efficiently by oversteering. Furthermore, the large velocity of the slingshot motion enables bacteria to move efficiently through environments that contain shear-thinning viscoelastic fluids, such as the extracellular polymeric substances (EPS) that bacteria secrete on surfaces during biofilm formation.
Collapse
|
47
|
Leng X, Zhu W, Jin J, Mao X. Evidence that a chaperone–usher-like pathway of Myxococcus xanthus functions in spore coat formation. Microbiology (Reading) 2011; 157:1886-1896. [DOI: 10.1099/mic.0.047134-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many bacteria use the chaperone–usher (CU) secretion pathway to assemble on their surfaces typical or atypical fimbrial organelles. Four consecutive genes of Myxococcus xanthus DK1622, MXAN3885–3882, were predicted to constitute an operon encoding a CU-like system involved in the assembly of the spore coat; however, experimental evidence supporting this hypothesis was lacking. In this study, co-transcription of MXAN3885–3883 was verified, and we found that this operon was expressed 12–15 h after initiation of M. xanthus development under conditions of stringent starvation. The MXAN3885 protein, which is highly homologous to, but expressed earlier than, the spore coat protein U of another M. xanthus strain, DZF1, was present mainly on the outer surface of myxospores. Inactivation of MXAN3883, encoding a putative outer membrane usher, inhibited assembly of MXAN3885 protein on spore surfaces and caused certain morphological alterations in the spore coat. Hence, the CU-like pathway in M. xanthus indeed functions in spore coat biogenesis. Based on chaperone amino acid sequence comparisons, our analysis suggests that the structural basis of the M. xanthus CU-like pathway for spore coat assembly may be different from that of most surface structures assembled by classical CU systems.
Collapse
Affiliation(s)
- Xiaoyan Leng
- Department of Biochemistry, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, PR China
- Key laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China
| | - Wei Zhu
- Department of Biochemistry, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, PR China
- Key laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China
| | - Jing Jin
- Department of Biochemistry, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, PR China
- Key laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China
| | - Xiaohua Mao
- Department of Biochemistry, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, PR China
- Key laboratory of Ministry of Education for Developmental Genes and Human Diseases, Southeast University, Nanjing, Jiangsu 210009, PR China
| |
Collapse
|
48
|
Hu W, Hossain M, Lux R, Wang J, Yang Z, Li Y, Shi W. Exopolysaccharide-independent social motility of Myxococcus xanthus. PLoS One 2011; 6:e16102. [PMID: 21245931 PMCID: PMC3016331 DOI: 10.1371/journal.pone.0016102] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 12/13/2010] [Indexed: 11/19/2022] Open
Abstract
Social motility (S motility), the coordinated movement of large cell groups on agar surfaces, of Myxococcus xanthus requires type IV pili (TFP) and exopolysaccharides (EPS). Previous models proposed that this behavior, which only occurred within cell groups, requires cycles of TFP extension and retraction triggered by the close interaction of TFP with EPS. However, the curious observation that M. xanthus can perform TFP-dependent motility at a single-cell level when placed onto polystyrene surfaces in a highly viscous medium containing 1% methylcellulose indicated that "S motility" is not limited to group movements. In an apparent further challenge of the previous findings for S motility, mutants defective in EPS production were found to perform TFP-dependent motility on polystyrene surface in methylcellulose-containing medium. By exploring the interactions between pilin and surface materials, we found that the binding of TFP onto polystyrene surfaces eliminated the requirement for EPS in EPS(-) cells and thus enabled TFP-dependent motility on a single cell level. However, the presence of a general anchoring surface in a viscous environment could not substitute for the role of cell surface EPS in group movement. Furthermore, EPS was found to serve as a self-produced anchoring substrate that can be shed onto surfaces to enable cells to conduct TFP-dependent motility regardless of surface properties. These results suggested that in certain environments, such as in methylcellulose solution, the cells could bypass the need for EPS to anchor their TPF and conduct single-cell S motility to promote exploratory movement of colonies over new specific surfaces.
Collapse
Affiliation(s)
- Wei Hu
- School of Dentistry, University
of California Los Angeles, Los Angeles, California, United States of America
- State Key Laboratory of Microbial
Technology, School of Life Science, Shandong University, Jinan, China
| | - Muhaiminu Hossain
- Molecular Biology Institute, University
of California Los Angeles, Los Angeles, California, United States of America
| | - Renate Lux
- School of Dentistry, University
of California Los Angeles, Los Angeles, California, United States of America
| | - Jing Wang
- School of Dentistry, University
of California Los Angeles, Los Angeles, California, United States of America
- State Key Laboratory of Microbial
Technology, School of Life Science, Shandong University, Jinan, China
| | - Zhe Yang
- Molecular Biology Institute, University
of California Los Angeles, Los Angeles, California, United States of America
| | - Yuezhong Li
- State Key Laboratory of Microbial
Technology, School of Life Science, Shandong University, Jinan, China
| | - Wenyuan Shi
- School of Dentistry, University
of California Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University
of California Los Angeles, Los Angeles, California, United States of America
| |
Collapse
|
49
|
Kim YH, Park KH, Kim SY, Ji ES, Kim JY, Lee SK, Yoo JS, Kim HS, Park YM. Identification of trimethylation at C-terminal lysine of pilin in the cyanobacterium Synechocystis PCC 6803. Biochem Biophys Res Commun 2010; 404:587-92. [PMID: 21130745 DOI: 10.1016/j.bbrc.2010.11.133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 11/24/2010] [Indexed: 12/13/2022]
Abstract
Various post-translational modifications (PTMs) of pilin in Synechocystis sp. PCC 6803 have been proposed. In this study, we investigated previously unidentified PTMs of pilin by mass spectrometry (MS). MALDI-TOF MS and TOF/TOF MS showed that the molecular mass of the C-terminal lysine of pilin was increased by 42Da, which could represent acetylation (ΔM=42.0470) or trimethylation (ΔM=42.0106). To discriminate between these isobaric modifications, the molecular mass of the C-terminal tryptic peptide was measured using 15T Fourier transform ion cyclotron resonance (FT-ICR) MS. The high magnetic field FT-ICR provided sub-ppm mass accuracy, revealing that the C-terminal lysine was modified by trimethylation. We could also detect the existence of mono- and di-methylation of the C-terminal lysine. Cells expressing a pilin point mutant with glutamine replacing the C-terminal lysine showed dramatically reduced motility and short pili. These findings suggest that trimethylation of pilin at the C-terminal lysine may be essential for the biogenesis of functional pili.
Collapse
Affiliation(s)
- Young Hye Kim
- Mass Spectrometry Research Center, Korea Basic Science Institute, Ochang 363-883, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
The in vitro antibiofilm activity of selected marine bacterial culture supernatants against Vibrio spp. Arch Microbiol 2010; 192:843-54. [DOI: 10.1007/s00203-010-0612-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/19/2010] [Accepted: 07/26/2010] [Indexed: 11/25/2022]
|