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Rapsinski GJ, Michaels LA, Hill M, Yarrington KD, Haas AL, D’Amico EJ, Armbruster CR, Zemke A, Limoli D, Bomberger JM. Pseudomonas aeruginosa senses and responds to epithelial potassium flux via Kdp operon to promote biofilm. PLoS Pathog 2024; 20:e1011453. [PMID: 38820569 PMCID: PMC11168685 DOI: 10.1371/journal.ppat.1011453] [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: 06/02/2023] [Revised: 06/12/2024] [Accepted: 05/21/2024] [Indexed: 06/02/2024] Open
Abstract
Mucosa-associated biofilms are associated with many human disease states, but the host mechanisms promoting biofilm remain unclear. In chronic respiratory diseases like cystic fibrosis (CF), Pseudomonas aeruginosa establishes chronic infection through biofilm formation. P. aeruginosa can be attracted to interspecies biofilms through potassium currents emanating from the biofilms. We hypothesized that P. aeruginosa could, similarly, sense and respond to the potassium efflux from human airway epithelial cells (AECs) to promote biofilm. Using respiratory epithelial co-culture biofilm imaging assays of P. aeruginosa grown in association with CF bronchial epithelial cells (CFBE41o-), we found that P. aeruginosa biofilm was increased by potassium efflux from AECs, as examined by potentiating large conductance potassium channel, BKCa (NS19504) potassium efflux. This phenotype is driven by increased bacterial attachment and increased coalescence of bacteria into aggregates. Conversely, biofilm formation was reduced when AECs were treated with a BKCa blocker (paxilline). Using an agar-based macroscopic chemotaxis assay, we determined that P. aeruginosa chemotaxes toward potassium and screened transposon mutants to discover that disruption of the high-sensitivity potassium transporter, KdpFABC, and the two-component potassium sensing system, KdpDE, reduces P. aeruginosa potassium chemotaxis. In respiratory epithelial co-culture biofilm imaging assays, a KdpFABCDE deficient P. aeruginosa strain demonstrated reduced biofilm growth in association with AECs while maintaining biofilm formation on abiotic surfaces. Furthermore, we determined that the Kdp operon is expressed in vivo in people with CF and the genes are conserved in CF isolates. Collectively, these data suggest that P. aeruginosa biofilm formation can be increased by attracting bacteria to the mucosal surface and enhancing coalescence into microcolonies through aberrant AEC potassium efflux sensed by the KdpFABCDE system. These findings suggest host electrochemical signaling can enhance biofilm, a novel host-pathogen interaction, and potassium flux could be a therapeutic target to prevent chronic infections in diseases with mucosa-associated biofilms, like CF.
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Affiliation(s)
- Glenn J. Rapsinski
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United State of America
- Division of Infectious Disease, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Lia A. Michaels
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Madison Hill
- Department of Biology, Saint Vincent College, Latrobe, Pennsylvania, United States of America
| | - Kaitlin D. Yarrington
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Allison L. Haas
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United State of America
| | - Emily J. D’Amico
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United State of America
| | - Catherine R. Armbruster
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United State of America
| | - Anna Zemke
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Dominique Limoli
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jennifer M. Bomberger
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United State of America
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Maumela P, Khwathisi A, Madala NE, Serepa-Dlamini MH. In silico biotechnological potential of Bacillus sp. strain MHSD_37 bacterial endophyte. BMC Genomics 2024; 25:399. [PMID: 38658836 PMCID: PMC11040839 DOI: 10.1186/s12864-024-10305-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 04/12/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND Endophytic bacteria possess a range of unique characteristics that enable them to successfully interact with their host and survive in adverse environments. This study employed in silico analysis to identify genes, from Bacillus sp. strain MHSD_37, with potential biotechnological applications. RESULTS The strain presented several endophytic lifestyle genes which encode for motility, quorum sensing, stress response, desiccation tolerance and root colonisation. The presence of plant growth promoting genes such as those involved in nitrogen fixation, nitrate assimilation, siderophores synthesis, seed germination and promotion of root nodule symbionts, was detected. Strain MHSD_37 also possessed genes involved in insect virulence and evasion of defence system. The genome analysis also identified the presence of genes involved in heavy metal tolerance, xenobiotic resistance, and the synthesis of siderophores involved in heavy metal tolerance. Furthermore, LC-MS analysis of the excretome identified secondary metabolites with biological activities such as anti-cancer, antimicrobial and applications as surfactants. CONCLUSIONS Strain MHSD_37 thereby demonstrated potential biotechnological application in bioremediation, biofertilisation and biocontrol. Moreover, the strain presented genes encoding products with potential novel application in bio-nanotechnology and pharmaceuticals.
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Affiliation(s)
- Pfariso Maumela
- Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Doornfontein Campus, 2028, Johannesburg, P.O. Box 17011, South Africa
| | - Adivhaho Khwathisi
- Department of Biochemistry and Microbiology, Faculty of Science, Engineering and Agriculture, University of Venda, Private Bag X5050, 0950, Thohoyandou, South Africa
| | - Ntakadzeni Edwin Madala
- Department of Biochemistry and Microbiology, Faculty of Science, Engineering and Agriculture, University of Venda, Private Bag X5050, 0950, Thohoyandou, South Africa
| | - Mahloro Hope Serepa-Dlamini
- Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Doornfontein Campus, 2028, Johannesburg, P.O. Box 17011, South Africa.
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Li J, Liu C, Wang S, Mao X. Staphylococcus aureus enters viable-but-nonculturable state in response to chitooligosaccharide stress by altering metabolic pattern and transmembrane transport function. Carbohydr Polym 2024; 330:121772. [PMID: 38368090 DOI: 10.1016/j.carbpol.2023.121772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/17/2023] [Accepted: 12/29/2023] [Indexed: 02/19/2024]
Abstract
Although chitooligosaccharide (COS) has attracted the attention of some researchers due to its good solubility and broad-spectrum antibacterial activity, our study found that Staphylococcus aureus treated with low concentration of COS actively entered the viable-but-nonculturable (VBNC) state to resist this environmental stress. In this study, the transcriptome of VBNC-state S. aureus after COS treatment was analyzed by RNA-sequencing. Compared with the control group, pathway enrichment analysis showed that COS-treated S. aureus adopted a series of adaptive adjustment strategies for survival, including significant up-regulation of the differential genes' expression of such as ABC transporters (metI, tagG), Sec dependent transport pathway (secDF), peptidoglycan synthesis pathway (murG) and alteration of their physiological metabolic patterns, where ATP depletion played a key role in the formation of the VBNC-state S. aureus. Further, by using oxidative phosphorylation uncoupling agent to adjust the initial level of ATP in S. aureus, it was found that the reduction of intracellular ATP level could accelerate the formation of VBNC state. Overall, our results preliminarily elucidated the molecular mechanism of COS inducing the VBNC-state S. aureus. It provided an important theoretical reference for further achieving effective bacterial inactivation by COS.
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Affiliation(s)
- Jiao Li
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China
| | - Chunhui Liu
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China
| | - Sai Wang
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China
| | - Xiangzhao Mao
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China.
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Alshehri WA, Abulfaraj AA, Alqahtani MD, Alomran MM, Alotaibi NM, Alwutayd K, Aloufi AS, Alshehrei FM, Alabbosh KF, Alshareef SA, Ashy RA, Refai MY, Jalal RS. Abundant resistome determinants in rhizosphere soil of the wild plant Abutilon fruticosum. AMB Express 2023; 13:92. [PMID: 37646836 PMCID: PMC10469157 DOI: 10.1186/s13568-023-01597-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/18/2023] [Indexed: 09/01/2023] Open
Abstract
A metagenomic whole genome shotgun sequencing approach was used for rhizospheric soil micribiome of the wild plant Abutilon fruticosum in order to detect antibiotic resistance genes (ARGs) along with their antibiotic resistance mechanisms and to detect potential risk of these ARGs to human health upon transfer to clinical isolates. The study emphasized the potential risk to human health of such human pathogenic or commensal bacteria, being transferred via food chain or horizontally transferred to human clinical isolates. The top highly abundant rhizospheric soil non-redundant ARGs that are prevalent in bacterial human pathogens or colonizers (commensal) included mtrA, soxR, vanRO, golS, rbpA, kdpE, rpoB2, arr-1, efrA and ileS genes. Human pathogenic/colonizer bacteria existing in this soil rhizosphere included members of genera Mycobacterium, Vibrio, Klebsiella, Stenotrophomonas, Pseudomonas, Nocardia, Salmonella, Escherichia, Citrobacter, Serratia, Shigella, Cronobacter and Bifidobacterium. These bacteria belong to phyla Actinobacteria and Proteobacteria. The most highly abundant resistance mechanisms included antibiotic efflux pump, antibiotic target alteration, antibiotic target protection and antibiotic inactivation. antimicrobial resistance (AMR) families of the resistance mechanism of antibiotic efflux pump included resistance-nodulation-cell division (RND) antibiotic efflux pump (for mtrA, soxR and golS genes), major facilitator superfamily (MFS) antibiotic efflux pump (for soxR gene), the two-component regulatory kdpDE system (for kdpE gene) and ATP-binding cassette (ABC) antibiotic efflux pump (for efrA gene). AMR families of the resistance mechanism of antibiotic target alteration included glycopeptide resistance gene cluster (for vanRO gene), rifamycin-resistant beta-subunit of RNA polymerase (for rpoB2 gene) and antibiotic-resistant isoleucyl-tRNA synthetase (for ileS gene). AMR families of the resistance mechanism of antibiotic target protection included bacterial RNA polymerase-binding protein (for RbpA gene), while those of the resistance mechanism of antibiotic inactivation included rifampin ADP-ribosyltransferase (for arr-1 gene). Better agricultural and food transport practices are required especially for edible plant parts or those used in folkloric medicine.
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Affiliation(s)
- Wafa A Alshehri
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Aala A Abulfaraj
- Biological Sciences Department, College of Science & Arts, King Abdulaziz University, 21911, Rabigh, Saudi Arabia
| | - Mashael D Alqahtani
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Maryam M Alomran
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Nahaa M Alotaibi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Khairiah Alwutayd
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Abeer S Aloufi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Fatimah M Alshehrei
- Department of Biology, Jumum College University, Umm Al-Qura University, P.O. Box 7388, 21955, Makkah, Saudi Arabia
| | - Khulood F Alabbosh
- Department of Biology, College of Science, University of Hail, Hail, Saudi Arabia
| | - Sahar A Alshareef
- Department of Biology, College of Science and Arts at Khulis, University of Jeddah, 21921, Jeddah, Saudi Arabia
| | - Ruba A Ashy
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Mohammed Y Refai
- Department of Biochemistry, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Rewaa S Jalal
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia.
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Poshvina DV, Dilbaryan DS, Kasyanov SP, Sadykova VS, Lapchinskaya OA, Rogozhin EA, Vasilchenko AS. Staphylococcus aureus is able to generate resistance to novel lipoglycopeptide antibiotic gausemycin A. Front Microbiol 2022; 13:963979. [PMID: 36246291 PMCID: PMC9558223 DOI: 10.3389/fmicb.2022.963979] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/14/2022] [Indexed: 11/13/2022] Open
Abstract
Gausemycin A is the first member of the novel lipoglycopeptides family produced by Streptomyces roseoflavus INA-Ac-5812. Gausemycin A has a pronounced bactericidal activity against methicillin-resistant Staphylococcus aureus. However, the ability of S. aureus to be resistant to gausemycin A has not been investigated yet. Using serial passaging, we have obtained the resistant variant S. aureus 5812R, which is 80 times more resistant compared to the parent strain. Susceptibility testing of S. aureus 5812R revealed the acquisition of cross-resistance to daptomycin, cefazolin, tetracycline, and gentamicin, while the resistance to vancomycin, nisin, and ramoplanin was absent. Whole genome sequencing revealed single nucleotide polymorphism (SNP) and deletions in S. aureus 5812R, among which are genes encoding efflux pump (sepA), the two-component Kdp system (kdpE), and the component of isoprenoid biosynthesis pathway (hepT). Phenotypically, S. aureus 5812R resembles a small-colony variant, as it is slow-growing, forms small colonies, and is deficient in pigments. Profiling of fatty acids (FA) composition constituting the cytoplasmic membrane of S. aureus 5812R revealed the prevalence of anteiso-branched FA, while straight FA was slightly less present. The evidence also showed that the gausemycin A-resistant strain has increased expression of the cls2 gene of the cardiolipin synthase. The performed checkerboard assay pointed out that the combination of gausemycin A and ciprofloxacin showed a synergistic effect against S. aureus 5812R.
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Affiliation(s)
- Darya V. Poshvina
- Laboratory of Antimicrobial Resistance, Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia
| | - Diana S. Dilbaryan
- Laboratory of Antimicrobial Resistance, Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia
| | - Sergey P. Kasyanov
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Vladivostok, Russia
| | | | | | - Eugene A. Rogozhin
- Gause Institute of New Antibiotics, Moscow, Russia
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Alexey S. Vasilchenko
- Laboratory of Antimicrobial Resistance, Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia
- *Correspondence: Alexey S. Vasilchenko
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Shami AY, Abulfaraj AA, Refai MY, Barqawi AA, Binothman N, Tashkandi MA, Baeissa HM, Baz L, Abuauf HW, Ashy RA, Jalal RS. Abundant antibiotic resistance genes in rhizobiome of the human edible Moringa oleifera medicinal plant. Front Microbiol 2022; 13:990169. [PMID: 36187977 PMCID: PMC9524394 DOI: 10.3389/fmicb.2022.990169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022] Open
Abstract
Moringa oleifera (or the miracle tree) is a wild plant species widely grown for its seed pods and leaves, and is used in traditional herbal medicine. The metagenomic whole genome shotgun sequencing (mWGS) approach was used to characterize antibiotic resistance genes (ARGs) of the rhizobiomes of this wild plant and surrounding bulk soil microbiomes and to figure out the chance and consequences for highly abundant ARGs, e.g., mtrA, golS, soxR, oleC, novA, kdpE, vanRO, parY, and rbpA, to horizontally transfer to human gut pathogens via mobile genetic elements (MGEs). The results indicated that abundance of these ARGs, except for golS, was higher in rhizosphere of M. oleifera than that in bulk soil microbiome with no signs of emerging new soil ARGs in either soil type. The most highly abundant metabolic processes of the most abundant ARGs were previously detected in members of phyla Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Firmicutes. These processes refer to three resistance mechanisms namely antibiotic efflux pump, antibiotic target alteration and antibiotic target protection. Antibiotic efflux mechanism included resistance-nodulation-cell division (RND), ATP-binding cassette (ABC), and major facilitator superfamily (MFS) antibiotics pumps as well as the two-component regulatory kdpDE system. Antibiotic target alteration included glycopeptide resistance gene cluster (vanRO), aminocoumarin resistance parY, and aminocoumarin self-resistance parY. While, antibiotic target protection mechanism included RbpA bacterial RNA polymerase (rpoB)-binding protein. The study supports the claim of the possible horizontal transfer of these ARGs to human gut and emergence of new multidrug resistant clinical isolates. Thus, careful agricultural practices are required especially for plants used in circles of human nutrition industry or in traditional medicine.
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Affiliation(s)
- Ashwag Y. Shami
- Department of Biology, College of Sciences, Princess Nourah bint Abdulrahman University, Riyadh 11617, Saudi Arabia
| | - Aala A. Abulfaraj
- Biological Sciences Department, College of Science and Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia
| | - Mohammed Y. Refai
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Aminah A. Barqawi
- Department of Chemistry, Al-Leith University College, Umm Al Qura University, Makkah, Saudi Arabia
| | - Najat Binothman
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh, Saudi Arabia
| | - Manal A. Tashkandi
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Hanadi M. Baeissa
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Lina Baz
- Department of Biochemistry, Faculty of Science—King Abdulaziz University, Jeddah, Saudi Arabia
| | - Haneen W. Abuauf
- Department of Biology, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Ruba A. Ashy
- Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Rewaa S. Jalal
- Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia
- *Correspondence: Rewaa S. Jalal,
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Ali M, Gu T, Yu X, Bashir A, Wang Z, Sun X, Ashraf NM, Li L. Identification of the Genes of the Plant Pathogen Pseudomonas syringae MB03 Required for the Nematicidal Activity Against Caenorhabditis elegans Through an Integrated Approach. Front Microbiol 2022; 13:826962. [PMID: 35356513 PMCID: PMC8959697 DOI: 10.3389/fmicb.2022.826962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/11/2022] [Indexed: 01/04/2023] Open
Abstract
Nematicidal potential of the common plant pathogen Pseudomonas syringae has been recently identified against Caenorhabditis elegans. The current study was designed to investigate the detailed genetic mechanism of the bacterial pathogenicity by applying comparative genomics, transcriptomics, mutant library screening, and protein expression. Results showed that P. syringae strain MB03 could kill C. elegans in the liquid assay by gut colonization. The genome of P. syringae MB03 was sequenced and comparative analysis including multi locus sequence typing, and genome-to-genome distance placed MB03 in phylogroup II of P. syringae. Furthermore, comparative genomics of MB03 with nematicidal strains of Pseudomonas aeruginosa (PAO1 and PA14) predicted 115 potential virulence factors in MB03. However, genes for previously reported nematicidal metabolites, such as phenazine, pyochelin, and pyrrolnitrin, were found absent in the MB03 genome. Transcriptomics analysis showed that the growth phase of the pathogen considerably affected the expression of virulence factors, as genes for the flagellum, glutamate ABC transporter, phoP/phoQ, fleS/fleR, type VI secretion system, and serralysin were highly up-regulated when stationary phase MB03 cells interacted with C. elegans. Additionally, screening of a transposon insertion mutant library led to the identification of other nematicidal genes such as acnA, gltP, oprD, and zapE. Finally, the nematicidal activity of selected proteins was confirmed by heterologous expression in Escherichia coli.
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Affiliation(s)
- Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad, Pakistan
| | - Tong Gu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xun Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Anum Bashir
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zhiyong Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaowen Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Naeem Mahmood Ashraf
- Department of Biochemistry and Biotechnology, University of Gujrat, Gujrat, Pakistan
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- *Correspondence: Lin Li,
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Luo A, Jing H, Yuan L, Wang Y, Xiao H, Zheng Q. Loss of Function of Scavenger Receptor SCAV-5 Protects C. elegans Against Pathogenic Bacteria. Front Cell Infect Microbiol 2021; 11:593745. [PMID: 34414127 PMCID: PMC8370389 DOI: 10.3389/fcimb.2021.593745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 07/08/2021] [Indexed: 11/13/2022] Open
Abstract
Scavenger receptors play a critical role in innate immunity by acting as the pattern-recognition receptors. There are six class B scavenger receptors homologs in C. elegans. However, it remains unclear whether they are required for host defense against bacterial pathogens. Here, we show that, of the six SCAV proteins, only loss of function scav-5 protect C. elegans against pathogenic bacteria S. typhimurium SL1344 and P. aeruginosa PA14 by different mechanism. scav-5 mutants are resistant to S. typhimurium SL1344 due to dietary restriction. While scav-5 acts upstream of or in parallel to tir-1 in conserved PMK-1 p38 MAPK pathway to upregulate the innate immune response to defend worms against P. aeruginosa PA14. This is the first demonstration of a role for SCAV-5 in host defense against pathogenic bacteria. Our results provide an important basis for further elucidating the underlying molecular mechanism by which scav-5 regulates innate immune responses.
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Affiliation(s)
- Aixiao Luo
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Huiru Jing
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Lei Yuan
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yanzhe Wang
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Hui Xiao
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Qian Zheng
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
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Pangenome Analysis of Mycobacterium tuberculosis Reveals Core-Drug Targets and Screening of Promising Lead Compounds for Drug Discovery. Antibiotics (Basel) 2020; 9:antibiotics9110819. [PMID: 33213029 PMCID: PMC7698547 DOI: 10.3390/antibiotics9110819] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/13/2020] [Accepted: 11/15/2020] [Indexed: 12/03/2022] Open
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis (M. tuberculosis), is one of the leading causes of human deaths globally according to the WHO TB 2019 report. The continuous rise in multi- and extensive-drug resistance in M. tuberculosis broadens the challenges to control tuberculosis. The availability of a large number of completely sequenced genomes of M. tuberculosis has provided an opportunity to explore the pangenome of the species along with the pan-phylogeny and to identify potential novel drug targets leading to drug discovery. We attempt to calculate the pangenome of M. tuberculosis that comprises a total of 150 complete genomes and performed the phylo-genomic classification and analysis. Further, the conserved core genome (1251 proteins) is subjected to various sequential filters (non-human homology, essentiality, virulence, physicochemical parameters, and pathway analysis) resulted in identification of eight putative broad-spectrum drug targets. Upon molecular docking analyses of these targets with ligands available at the DrugBank database shortlisted a total of five promising ligands with projected inhibitory potential; namely, 2′deoxy-thymidine-5′-diphospho-alpha-d-glucose, uridine diphosphate glucose, 2′-deoxy-thymidine-beta-l-rhamnose, thymidine-5′-triphosphate, and citicoline. We are confident that with further lead optimization and experimental validation, these lead compounds may provide a sound basis to develop safe and effective drugs against tuberculosis disease in humans.
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Kumar S, Gillilan RE, Yernool DA. Structure and function of the juxtamembrane GAF domain of potassium biosensor KdpD. Protein Sci 2020; 29:2009-2021. [PMID: 32713093 DOI: 10.1002/pro.3920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 11/10/2022]
Abstract
KdpD/KdpE two-component signaling system regulates expression of a high affinity potassium transporter responsible for potassium homeostasis. The C-terminal module of KdpD consists of a GAF domain linked to a histidine kinase domain. Whereas certain GAF domains act as regulators by binding cyclic nucleotides, the role of the juxtamembrane GAF domain in KdpD is unknown. We report the high-resolution crystal structure of KdpD GAF domain (KdpDG ) consisting of five α-helices, four β-sheets and two large loops. KdpDG forms a symmetry-related dimer, wherein parallelly arranged monomers contribute to a four-helix bundle at the dimer-interface, SAXS analysis of KdpD C-terminal module reveals an elongated structure that is a dimer in solution. Substitution of conserved residues with various residues that disrupt the dimer interface produce a range of effects on gene expression demonstrating the importance of the interface in inactive to active transitions during signaling. Comparison of ligand binding site of the classic cyclic nucleotide-binding GAF domains to KdpDG reveals structural differences arising from naturally occurring substitutions in primary sequence of KdpDG that modifies the canonical NKFDE sequence motif required for cyclic nucleotide binding. Together these results suggest a structural role for KdpDG in dimerization and transmission of signal to the kinase domain.
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Affiliation(s)
- Shivesh Kumar
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA.,Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, Ithaca, New York, USA
| | - Dinesh A Yernool
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
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Murret-Labarthe C, Kerhoas M, Dufresne K, Daigle F. New Roles for Two-Component System Response Regulators of Salmonella enterica Serovar Typhi during Host Cell Interactions. Microorganisms 2020; 8:microorganisms8050722. [PMID: 32413972 PMCID: PMC7285189 DOI: 10.3390/microorganisms8050722] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/04/2020] [Accepted: 05/09/2020] [Indexed: 12/12/2022] Open
Abstract
In order to survive external stresses, bacteria need to adapt quickly to changes in their environment. One adaptive mechanism is to coordinate and alter their gene expression by using two-component systems (TCS). TCS are composed of a sensor kinase that activates a transcriptional response regulator by phosphorylation. TCS are involved in motility, virulence, nutrient acquisition, and envelope stress in many bacteria. The pathogenic bacteria Salmonella enterica serovar Typhi (S. Typhi) possess 30 TCSs, is specific to humans, and causes typhoid fever. Here, we have individually deleted each of the 30 response regulators. We have determined their role during interaction with host cells (epithelial cells and macrophages). Deletion of most of the systems (24 out of 30) resulted in a significant change during infection. We have identified 32 new phenotypes associated with TCS of S. Typhi. Some previously known phenotypes associated with TCSs in Salmonella were also confirmed. We have also uncovered phenotypic divergence between Salmonella serovars, as distinct phenotypes between S. Typhi and S. Typhimurium were identified for cpxR. This finding highlights the importance of specifically studying S. Typhi to understand its pathogenesis mechanisms and to develop strategies to potentially reduce typhoid infections.
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12
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Liao X, Liu D, Ding T. Nonthermal Plasma Induces the Viable-but-Nonculturable State in Staphylococcus aureus via Metabolic Suppression and the Oxidative Stress Response. Appl Environ Microbiol 2020; 86:e02216-19. [PMID: 31836577 PMCID: PMC7028965 DOI: 10.1128/aem.02216-19] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/04/2019] [Indexed: 12/18/2022] Open
Abstract
As a novel nonthermal technology, nonthermal plasma (NTP) has attracted a lot of attention. However, it could induce microorganisms into a viable but nonculturable (VBNC) state, posing a potential risk to food safety and public health. In this study, the molecular mechanisms of VBNC Staphylococcus aureus induced by NTP were investigated. With the use of a propidium monoazide quantitative PCR (PMA-qPCR) technique combined with a plate count method, we confirmed that 8.1 to 24.3 kJ NTP induced S. aureus into a VBNC state at a level of 7.4 to 7.6 log10 CFU/ml. The transcriptomic analysis was conducted and revealed that most energy-dependent physiological activities (e.g., metabolism) were arrested in VBNC S. aureus, while the oxidative stress response-related genes (katA, dps, msrB, msrA, and trxA) were significantly upregulated. In addition, this study showed that the ATP depletion by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) pretreatment could accelerate the formation of VBNC S. aureus The NTP-generated oxidative stress triggers the staphylococcal oxidative stress response, which consumes part of cellular energy (e.g., ATP). The energy allocation is therefore changed, and the energy assigned for other energy-dependent physiological activities (cell growth and division, etc.) is reduced, subsequently forcing S. aureus into a VBNC state. Therefore, the alterations of energy allocation should be some of the major contributors to the induction of VBNC S. aureus with NTP exposure. This study provides valuable knowledge for controlling the formation of VBNC S. aureus during NTP treatment.IMPORTANCE In recent years, nonthermal plasma (NTP) technology has received a lot of attention as a promising alternative to thermal pasteurization in the food industry. However, little is known about the microbial stress response toward NTP, which could be a potential risk to food safety and impede the development of NTP. A viable but nonculturable (VBNC) state is one of the most common survival strategies employed by microorganisms against external stress. This study investigated the mechanisms of the formation of VBNC Staphylococcus aureus by NTP in a more comprehensive and systematic aspect than had been done before. Our work confirmed that the NTP-generated oxidative stress induced changes in energy allocation as a driving force for the formation of VBNC S. aureus This study could provide better knowledge for controlling the occurrence of VBNC S. aureus induced by NTP, which could lead to more rational design and ensure the development of safe foods.
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Affiliation(s)
- Xinyu Liao
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Donghong Liu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Tian Ding
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
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13
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Tang Y, Davies R, Petrovska L. Identification of Genetic Features for Attenuation of Two Salmonella Enteritidis Vaccine Strains and Differentiation of These From Wildtype Isolates Using Whole Genome Sequencing. Front Vet Sci 2019; 6:447. [PMID: 31921908 PMCID: PMC6930191 DOI: 10.3389/fvets.2019.00447] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/26/2019] [Indexed: 01/10/2023] Open
Abstract
Salmonella Enteritidis is a major cause of salmonellosis worldwide and more than 80% of outbreaks investigated in Europe have been associated with the consumption of poorly cooked eggs or foods containing raw eggs. Vaccination has been proven to be one of the most important measures to control Salmonella Enteritidis infections in poultry farms as it can decrease colonization of the reproductive organs and intestinal tract of laying hens, thereby reducing egg contamination. Differentiation of live vaccine from field or wild type S. Enteritidis isolates in poultry is essential for monitoring of veterinary isolates and targetting control actions. Due to decreasing costs, whole genome sequencing (WGS) is becoming a key tool for characterization of Salmonella isolates, including vaccine strains. Using WGS we described the genetic changes in the live attenuated Salmovac 440 and AviPro SALMONELLA VAC E vaccine strains and developed a method for differentiation from the wildtype S. Enteritidis strains. SNP analysis confirmed that streptomycin resistance was associated with a Lys43Arg missense mutation in the rpsL gene whilst 3 missense mutations in acrB and 1 missense mutation in acrA confer erythromycin sensitivity in AviPro SALMONELLA VAC E. Further mutations Arg242His in purK and Gly236Arg in the hisB gene were related to adenine and histidine dependencies in Salmovac 440. Unique SNPs were used to construct a database of variants for differentiation of vaccine from the wildtype isolates. Two fragments from each vaccine were represented in the database to ensure high accuracy. Each of the two selected Salmovac 440 fragments differed by 6 SNPs from the wildtype and the AviPro SALMONELLA VAC E fragments differed by 4 and 6 SNPs, respectively. CD-hit software was applied to cluster similar fragments that produced the best fit output when searched with SRST2. The developed vaccine differentiation method was tested with 1,253 genome samples including field isolates of Salmovac 440 (n = 51), field isolates of AviPro SALMONELLA VAC E (n = 13), S. Gallinarum (n = 19), S. Pullorum (n = 116), S. Enteritidis (n = 244), S. Typhimurium (n = 810) and achieved 100% sensitivity and specificity.
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Affiliation(s)
- Yue Tang
- Department of Bacteriology, Animal and Plant Health Agency, Addlestone, United Kingdom
| | | | - Liljana Petrovska
- Department of Bacteriology, Animal and Plant Health Agency, Addlestone, United Kingdom
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14
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Akgul A, Nho SW, Kalindamar S, Tekedar HC, Abdalhamed H, Lawrence ML, Karsi A. Universal Stress Proteins Contribute Edwardsiella ictaluri Virulence in Catfish. Front Microbiol 2018; 9:2931. [PMID: 30546354 PMCID: PMC6279896 DOI: 10.3389/fmicb.2018.02931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 11/14/2018] [Indexed: 11/21/2022] Open
Abstract
Edwardsiella ictaluri is an intracellular Gram-negative facultative pathogen causing enteric septicemia of catfish (ESC), a common disease resulting in substantial economic losses in the U.S. catfish industry. Previously, we demonstrated that several universal stress proteins (USPs) are highly expressed under in vitro and in vivo stress conditions, indicating their importance for E. ictaluri survival. However, the roles of these USPs in E. ictaluri virulence is not known yet. In this work, 10 usp genes of E. ictaluri were in-frame deleted and characterized in vitro and in vivo. Results show that all USP mutants were sensitive to acidic condition (pH 5.5), and EiΔusp05 and EiΔusp08 were very sensitive to oxidative stress (0.1% H2O2). Virulence studies indicated that EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 were attenuated significantly compared to E. ictaluri wild-type (EiWT; 20, 45, 20, 20, 55, and 10% vs. 74.1% mortality, respectively). Efficacy experiments showed that vaccination of catfish fingerlings with EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 provided complete protection against EiWT compared to sham-vaccinated fish (0% vs. 58.33% mortality). Our results support that USPs contribute E. ictaluri virulence in catfish.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Seong Won Nho
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Safak Kalindamar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Hossam Abdalhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
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15
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Yang RL, Deng CY, Wei JW, He W, Li AN, Qian W. A Large-Scale Mutational Analysis of Two-Component Signaling Systems of Lonsdalea quercina Revealed that KdpD-KdpE Regulates Bacterial Virulence Against Host Poplar Trees. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:724-736. [PMID: 29424663 DOI: 10.1094/mpmi-10-17-0248-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Poplar, which is a dominant species in plant communities distributed in the northern hemisphere, is commonly used as a model plant in forestry studies. Poplar production can be inhibited by infections caused by bacteria, including Lonsdalea quercina subsp. populi, which is a gram-negative bacterium responsible for bark canker disease. However, the molecular basis of the pathogenesis remains uncharacterized. In this study, we annotated the two-component signal transduction systems (TCSs) encoded by the L. quercina subsp. populi N-5-1 genome and identified 18 putative histidine kinases and 24 response regulators. A large-scale mutational analysis revealed that 19 TCS genes regulated bacterial virulence against poplar trees. Additionally, the deletion of kdpE or overexpression of kdpD resulted in almost complete loss of bacterial virulence. We observed that kdpE and kdpD formed a bi-cistronic operon. KdpD exhibited autokinase activity and could bind to KdpE (Kd = 5.73 ± 0.64 μM). Furthermore, KdpE is an OmpR family response regulator. A chromatin immunoprecipitation sequencing analysis revealed that KdpE binds to an imperfect palindromic sequence within the promoters of 44 genes, including stress response genes Lqp0434, Lqp3037, and Lqp3270. A comprehensive analysis of TCS functions may help to characterize the regulation of poplar bark canker disease.
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Affiliation(s)
- Ruo-Lan Yang
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
| | - Chao-Ying Deng
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
| | - Jin-Wei Wei
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
- 3 School of Biological Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei He
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Ai-Ning Li
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Wei Qian
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
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16
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Akgul A, Akgul A, Lawrence ML, Karsi A. Stress-related genes promote Edwardsiella ictaluri pathogenesis. PLoS One 2018; 13:e0194669. [PMID: 29554143 PMCID: PMC5858854 DOI: 10.1371/journal.pone.0194669] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/07/2018] [Indexed: 12/22/2022] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative anaerobic rod and the causative agent of enteric septicemia of channel catfish (ESC), which is one of the most prevalent diseases of catfish, causing significant economic losses in the catfish industry. E. ictaluri is resistant to complement system and macrophage killing, which results in rapid systemic septicemia. However, mechanisms of E. ictaluri stress responses under conditions of host environment are not studied well. Therefore, in this work, we report E. ictaluri stress responses during hydrogen peroxide, low pH, and catfish serum stresses as well as during catfish invasion. E. ictaluri stress responses were characterized by identifying expression of 13 universal stress protein (USP) genes (usp01-usp13) and seven USP-interacting protein genes (groEL, groES, dnaK, grpE, and clpB, grpE, relA). Data indicated that three usp genes (usp05, usp07, and usp13) were highly expressed in all stress conditions. Similarly, E. ictaluri heat shock proteins groEL, groES, dnaK, grpE, and clpB were highly expressed in oxidative stress. Also, E. ictaluri grpE and relA were highly expressed in catfish spleen and head kidney. These findings contribute to our understanding of stress response mechanisms in E. ictaluri stress response, and stress-related proteins that are essential for E. ictaluri could be potential targets for live attenuated vaccine development against ESC.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Ayfer Akgul
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Mark L. Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
- * E-mail:
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17
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Ali MK, Li X, Tang Q, Liu X, Chen F, Xiao J, Ali M, Chou SH, He J. Regulation of Inducible Potassium Transporter KdpFABC by the KdpD/KdpE Two-Component System in Mycobacterium smegmatis. Front Microbiol 2017; 8:570. [PMID: 28484428 PMCID: PMC5401905 DOI: 10.3389/fmicb.2017.00570] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/20/2017] [Indexed: 12/28/2022] Open
Abstract
Kdp-ATPase is an inducible high affinity potassium uptake system that is widely distributed in bacteria, and is generally regulated by the KdpD/KdpE two-component system (TCS). In this study, conducted on Mycobacterium smegmatis, the kdpFABC (encoding Kdp-ATPase) expression was found to be affected by low concentration of K+, high concentrations of Na+, and/or [Formula: see text] of the medium. The KdpE was found to be a transcriptional regulator that bound to a specific 22-bp sequence in the promoter region of kdpFABC operon to positively regulate kdpFABC expression. The KdpE binding motif was highly conserved in the promoters of kdpFABC among the mycobacterial species. 5'-RACE data indicated a transcriptional start site (TSS) of the kdpFABC operon within the coding sequence of MSMEG_5391, which comprised a 120-bp long 5'-UTR and an open reading frame of the 87-bp kdpF gene. The kdpE deletion resulted in altered growth rate under normal and low K+ conditions. Furthermore, under K+ limiting conditions, a single transcript (kdpFABCDE) spanning kdpFABC and kdpDE operons was observed. This study provided the first insight into the regulation of kdpFABC operon by the KdpD/KdpE TCS in M. smegmatis.
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Affiliation(s)
- Maria K Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Qing Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Xiaoyu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Fang Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Jinfeng Xiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China.,Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan
| | - Shan-Ho Chou
- Institute of Biochemistry and NCHU Agricultural Biotechnology Center, National Chung Hsing UniversityTaichung, Taiwan
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
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18
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Head BP, Olaitan AO, Aballay A. Role of GATA transcription factor ELT-2 and p38 MAPK PMK-1 in recovery from acute P. aeruginosa infection in C. elegans. Virulence 2016; 8:261-274. [PMID: 27600703 PMCID: PMC5411242 DOI: 10.1080/21505594.2016.1222334] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Infectious diseases caused by bacterial pathogens reduce the fitness of their associated host but are generally limited in duration. In order for the diseased host to regain any lost fitness upon recovery, a variety of molecular, cellular, and physiological processes must be employed. To better understand mechanisms underlying the recovery process, we have modeled an acute Pseudomonas aeruginosa infection in C. elegans using brief exposures to this pathogen and subsequent antibiotic treatment. To identify host genes altered during recovery from P. aeruginosa infection, we performed whole genome expression profiling. The analysis of this dataset indicated that the activity of the host immune system is down-regulated upon recovery and revealed shared and pathogen-specific host responses during recovery. We determined that the GATA transcription factor ELT-2 and the p38 MAP kinase PMK-1 are necessary for animals to successfully recover from an acute P. aeruginosa infection. In addition, we found that ELT-2 plays a more prominent and earlier role than PMK-1 during recovery. Our data sheds further light on the molecular mechanisms and transcriptional programs involved in recovery from an acute bacterial infection, which provides a better understanding of the entire infectious disease process.
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Affiliation(s)
- Brian P Head
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
| | - Abiola O Olaitan
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
| | - Alejandro Aballay
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
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19
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Experimental Phage Therapy for Burkholderia pseudomallei Infection. PLoS One 2016; 11:e0158213. [PMID: 27387381 PMCID: PMC4936672 DOI: 10.1371/journal.pone.0158213] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 06/13/2016] [Indexed: 12/19/2022] Open
Abstract
Burkholderia pseudomallei is an intracellular Gram-negative bacterial pathogen intrinsically resistant to a variety of antibiotics. Phages have been developed for use as an alternative treatment therapy, particularly for bacterial infections that do not respond to conventional antibiotics. In this study, we investigated the use of phages to treat cells infected with B. pseudomallei. Phage C34 isolated from seawater was purified and characterised on the basis of its host range and morphology using transmission electron microscopy (TEM). Phage C34 was able to lyse 39.5% of B. pseudomallei clinical strains. Due to the presence of contractile tail, phage C34 is classified as a member of the family Myoviridae, a tailed double-stranded DNA virus. When 2 × 105 A549 cells were exposed to 2 × 107 PFU of phage C34, 24 hours prior to infection with 2 × 106 CFU of B. pseudomallei, it was found that the survivability of the cells increased to 41.6 ± 6.8% as compared to 22.8 ± 6.0% in untreated control. Additionally, application of phage successfully rescued 33.3% of mice infected with B. pseudomallei and significantly reduced the bacterial load in the spleen of the phage-treated mice. These findings indicate that phage can be a potential antimicrobial agent for B. pseudomallei infections.
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20
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Ali M, Sun Y, Xie L, Yu H, Bashir A, Li L. The Pathogenicity of Pseudomonas syringae MB03 against Caenorhabditis elegans and the Transcriptional Response of Nematicidal Genes upon Different Nutritional Conditions. Front Microbiol 2016; 7:805. [PMID: 27303387 PMCID: PMC4884745 DOI: 10.3389/fmicb.2016.00805] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/12/2016] [Indexed: 12/22/2022] Open
Abstract
Different species of the Pseudomonas genus have been reported for their pathogenic potential against animal cells. However, the pathogenicity of Pseudomonas syringae against Caenorhabditis elegans has never been reported. In this study, the interaction of P. syringae MB03 with C. elegans was studied. Different bioassays such as killing assay, lawn leaving assay, food preference assay, L4 growth assay and newly developed “secretion assay” were performed to evaluate the pathogenic potential of P. syringae on different growth media. The results of the killing assay showed that P. syringae MB03 was able to kill C. elegans under specific conditions, as the interaction between the host and the pathogen varied from non-pathogenic (assay on NGM medium) to pathogenic (assay on PG medium). The lawn leaving assay and the food preference assay illustrated that C. elegans identified P. syringae MB03 as a pathogen when assays were performed on PG medium. Green fluorescent protein was used as the reporter protein to study gut colonization by P. syringae MB03. Our results suggested that MB03 has the ability to colonize the gut of C. elegans. Furthermore, to probe the role of selected virulence determinants, qRT-PCR was used. The genes for pyoverdine, phoQ/phoP, phoR/phoB, and flagella were up regulated during the interaction of P. syringae MB03 and C. elegans on PG medium. Other than these, the genes for some proteases, such as pepP, clpA, and clpS, were also up regulated. On the other hand, kdpD and kdpB were down regulated more than threefold in the NGM – C. elegans interaction model. The deletion of the kdpD and kdpE genes altered the pathogenicity of the bacterial strain against C. elegans. Overall, our results suggested that the killing of C. elegans by P. syringae requires a prolonged interaction between the host and pathogen in an agar-based assay. Moreover, it seemed that some toxic metabolites were secreted by the bacterial strain that were sensed by C. elegans. Previously, it was believed that P. syringae could not damage animal cells. However, this study provides evidence of the pathogenic behavior of P. syringae against C. elegans.
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Affiliation(s)
- Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural UniversityWuhan, China; Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan
| | - Yu Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Wuhan, China
| | - Li Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Wuhan, China
| | - Huafu Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Wuhan, China
| | - Anum Bashir
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Wuhan, China
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Wuhan, China
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21
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Ryan D, Pati NB, Ojha UK, Padhi C, Ray S, Jaiswal S, Singh GP, Mannala GK, Schultze T, Chakraborty T, Suar M. Global transcriptome and mutagenic analyses of the acid tolerance response of Salmonella enterica serovar Typhimurium. Appl Environ Microbiol 2015; 81:8054-65. [PMID: 26386064 PMCID: PMC4651094 DOI: 10.1128/aem.02172-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/01/2015] [Indexed: 01/18/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than -1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K(+) binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject.
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Affiliation(s)
- Daniel Ryan
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Niladri Bhusan Pati
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Urmesh K Ojha
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | | | - Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Sangeeta Jaiswal
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Gajinder P Singh
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Gopala K Mannala
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Tilman Schultze
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Trinad Chakraborty
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
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Gannoun-Zaki L, Belon C, Dupont C, Hilbert F, Kremer L, Blanc-Potard AB. Overexpression of theSalmonellaKdpF membrane peptide modulates expression ofkdpgenes and intramacrophage growth. FEMS Microbiol Lett 2014; 359:34-41. [DOI: 10.1111/1574-6968.12559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/09/2014] [Accepted: 07/25/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Laila Gannoun-Zaki
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques; Universités de Montpellier 2 et 1; CNRS-UMR5235; Montpellier; France
| | - Claudine Belon
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques; Universités de Montpellier 2 et 1; CNRS-UMR5235; Montpellier; France
| | - Christian Dupont
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques; Universités de Montpellier 2 et 1; CNRS-UMR5235; Montpellier; France
| | - Friederike Hilbert
- Institute of Meat Hygiene; Meat Technology and Food Science; University of Veterinary Medicine Vienna; Vienna Austria
| | - Laurent Kremer
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques; Universités de Montpellier 2 et 1; CNRS-UMR5235; Montpellier; France
- INSERM; DIMNP; CNRS-UMR5235; Montpellier France
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques; Universités de Montpellier 2 et 1; CNRS-UMR5235; Montpellier; France
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Agrawal R, Saini DK. Rv1027c-Rv1028c encode functional KdpDE two--component system in Mycobacterium tuberculosis. Biochem Biophys Res Commun 2014; 446:1172-8. [PMID: 24667597 DOI: 10.1016/j.bbrc.2014.03.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
In Mycobacteriumtuberculosis Rv1027c-Rv1028c genes are predicted to encode KdpDE two component system, which is highly conserved across all bacterial species. Here, we show that the system is functionally active and KdpD sensor kinase undergoes autophosphorylation and transfers phosphoryl group to KdpE, response regulator protein. We identified His(642) and Asp(52) as conserved phosphorylation sites in KdpD and KdpE respectively and by SPR analysis confirmed the physical interaction between them. KdpD was purified with prebound divalent ions and their importance in phosphorylation was established using protein refolding and ion chelation approaches. Genetically a single transcript encoded both KdpD and KdpE proteins. Overall, we report that M. tuberculosis KdpDE system operates like a canonical two component system.
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Affiliation(s)
- Ruchi Agrawal
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Deepak Kumar Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.
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24
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Abstract
The two-component system (TCS) KdpD/KdpE, extensively studied for its regulatory role in potassium (K+) transport, has more recently been identified as an adaptive regulator involved in the virulence and intracellular survival of pathogenic bacteria, including Staphylococcus aureus, entero-haemorrhagic Escherichia coli, Salmonella typhimurium, Yersinia pestis, Francisella species, Photorhabdus asymbiotica, and mycobacteria. Key homeostasis requirements monitored by KdpD/KdpE and other TCSs such as PhoP/PhoQ are critical to survival in the stressful conditions encountered by pathogens during host interactions. It follows these TCSs may therefore acquire adaptive roles in response to selective pressures associated with adopting a pathogenic lifestyle. Given the central role of K+ in virulence, we propose that KdpD/KdpE, as a regulator of a high-affinity K+ pump, has evolved virulence-related regulatory functions. In support of this hypothesis, we review the role of KdpD/KdpE in bacterial infection and summarize evidence that (i) KdpD/KdpE production is correlated with enhanced virulence and survival, (ii) KdpE regulates a range of virulence loci through direct promoter binding, and (iii) KdpD/KdpE regulation responds to virulence-related conditions including phagocytosis, exposure to microbicides, quorum sensing signals, and host hormones. Furthermore, antimicrobial stress, osmotic stress, and oxidative stress are associated with KdpD/KdpE activity, and the system's accessory components (which allow TCS fine-tuning or crosstalk) provide links to stress response pathways. KdpD/KdpE therefore appears to be an important adaptive TCS employed during host infection, promoting bacterial virulence and survival through mechanisms both related to and distinct from its conserved role in K+ regulation.
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Affiliation(s)
- Zoë N. Freeman
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Steve Dorus
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Nicholas R. Waterfield
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- * E-mail:
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25
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Interplay between the QseC and QseE bacterial adrenergic sensor kinases in Salmonella enterica serovar Typhimurium pathogenesis. Infect Immun 2012; 80:4344-53. [PMID: 23027532 DOI: 10.1128/iai.00803-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial adrenergic sensor kinases QseC and QseE respond to epinephrine and/or norepinephrine to initiate a complex phosphorelay regulatory cascade that modulates virulence gene expression in several pathogens. We have previously shown that QseC activates virulence gene expression in Salmonella enterica serovar Typhimurium. Here we report the role of QseE in S. Typhimurium pathogenesis as well as the interplay between these two histidine sensor kinases in gene regulation. An S. Typhimurium qseE mutant is hampered in the invasion of epithelial cells and intramacrophage replication. The ΔqseC strain is highly attenuated for intramacrophage survival but has only a minor defect in invasion. However, the ΔqseEC strain has only a slight attenuation in invasion, mirroring the ΔqseC strain, and has an intermediary intramacrophage replication defect in comparison to the ΔqseE and ΔqseC strains. The expressions of the sipA and sopB genes, involved in the invasion of epithelial cells, are activated by epinephrine via QseE. The expression levels of these genes are still decreased in the ΔqseEC double mutant, albeit to a lesser extent, congruent with the invasion phenotype of this mutant. The expression level of the sifA gene, important for intramacrophage replication, is decreased in the qseE mutant and the ΔqseEC double mutant grown in vitro. However, as previously reported by us, the epinephrine-dependent activation of this gene occurs via QseC. In the systemic model of S. Typhimurium infection of BALB/c mice, the qseC and qseE mutants are highly attenuated, while the double mutant has an intermediary phenotype. Altogether, these data suggest that both adrenergic sensors play an important role in modulating several aspects of S. Typhimurium pathogenesis.
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26
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Lüttmann D, Göpel Y, Görke B. The phosphotransferase protein EIIA(Ntr) modulates the phosphate starvation response through interaction with histidine kinase PhoR in Escherichia coli. Mol Microbiol 2012; 86:96-110. [PMID: 22812494 DOI: 10.1111/j.1365-2958.2012.08176.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many Proteobacteria possess the paralogous PTS(Ntr), in addition to the sugar transport phosphotransferase system (PTS). In the PTS(Ntr) phosphoryl-groups are transferred from phosphoenolpyruvate to protein EIIA(Ntr) via the phosphotransferases EI(Ntr) and NPr. The PTS(Ntr) has been implicated in regulation of diverse physiological processes. In Escherichia coli, the PTS(Ntr) plays a role in potassium homeostasis. In particular, EIIA(Ntr) binds to and stimulates activity of a two-component histidine kinase (KdpD) resulting in increased expression of the genes encoding the high-affinity K(+) transporter KdpFABC. Here, we show that the phosphate (pho) regulon is likewise modulated by PTS(Ntr). The pho regulon, which comprises more than 30 genes, is activated by the two-component system PhoR/PhoB under conditions of phosphate starvation. Mutants lacking EIIA(Ntr) are unable to fully activate the pho genes and exhibit a growth delay upon adaptation to phosphate limitation. In contrast, pho expression is increased above the wild-type level in mutants deficient for EIIA(Ntr) phosphorylation suggesting that non-phosphorylated EIIA(Ntr) modulates pho. Protein interaction analyses reveal binding of EIIA(Ntr) to histidine kinase PhoR. This interaction increases the amount of phosphorylated response regulator PhoB. Thus, EIIA(Ntr) is an accessory protein that modulates the activities of two distinct sensor kinases, KdpD and PhoR, in E. coli.
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Affiliation(s)
- Denise Lüttmann
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, Grisebachstrasse 8, 37077 Göttingen, Germany
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Feinbaum RL, Urbach JM, Liberati NT, Djonovic S, Adonizio A, Carvunis AR, Ausubel FM. Genome-wide identification of Pseudomonas aeruginosa virulence-related genes using a Caenorhabditis elegans infection model. PLoS Pathog 2012; 8:e1002813. [PMID: 22911607 PMCID: PMC3406104 DOI: 10.1371/journal.ppat.1002813] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/06/2012] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa strain PA14 is an opportunistic human pathogen capable of infecting a wide range of organisms including the nematode Caenorhabditis elegans. We used a non-redundant transposon mutant library consisting of 5,850 clones corresponding to 75% of the total and approximately 80% of the non-essential PA14 ORFs to carry out a genome-wide screen for attenuation of PA14 virulence in C. elegans. We defined a functionally diverse 180 mutant set (representing 170 unique genes) necessary for normal levels of virulence that included both known and novel virulence factors. Seven previously uncharacterized virulence genes (ABC transporters PchH and PchI, aminopeptidase PepP, ATPase/molecular chaperone ClpA, cold shock domain protein PA0456, putative enoyl-CoA hydratase/isomerase PA0745, and putative transcriptional regulator PA14_27700) were characterized with respect to pigment production and motility and all but one of these mutants exhibited pleiotropic defects in addition to their avirulent phenotype. We examined the collection of genes required for normal levels of PA14 virulence with respect to occurrence in P. aeruginosa strain-specific genomic regions, location on putative and known genomic islands, and phylogenetic distribution across prokaryotes. Genes predominantly contributing to virulence in C. elegans showed neither a bias for strain-specific regions of the P. aeruginosa genome nor for putatively horizontally transferred genomic islands. Instead, within the collection of virulence-related PA14 genes, there was an overrepresentation of genes with a broad phylogenetic distribution that also occur with high frequency in many prokaryotic clades, suggesting that in aggregate the genes required for PA14 virulence in C. elegans are biased towards evolutionarily conserved genes.
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Affiliation(s)
- Rhonda L Feinbaum
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
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