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Alcolea-Medina A, Snell LB, Payne L, Alder CJ, Turnbull JD, Charalampous T, Bryan L, Klein JL, Edgeworth JD, Batra R, Goodman AL. Variovorax durovernensis sp. nov., a novel species isolated from an infected prosthetic aortic graft in a human. Int J Syst Evol Microbiol 2023; 73. [PMID: 38050797 DOI: 10.1099/ijsem.0.006184] [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] [Indexed: 12/06/2023] Open
Abstract
A novel bacterial strain, GSTT-20T was isolated from an infected, prosthetic endovascular graft explanted from a shepherd in London, United Kingdom. This strain was an aerobic, catalase-positive, oxidase-negative, Gram-stain-negative, motile, curved rod. It grew on blood agar, chocolate agar and MacConkey agar incubated at 37 °C in an aerobic environment after 48 h, appearing as yellow, mucoid colonies. Analysis of the complete 16S rRNA gene sequence showed closest similarity to Variovorax paradoxus with 99.6 % identity and Variovorax boronicumulans with 99.5 % identity. Phylogenetic analysis of the 16S rRNA gene sequence and phylogenomic analysis of single nucleotide polymorphisms within 1530 core genes showed GSTT-20T forms a distinct lineage in the genus Variovorax of the family Comamonadaceae. In silico DNA-DNA hybridization assays against GSTT-20T were estimated at 32.1 % for V. boronicumulans and 31.9 % for V. paradoxus. Genome similarity based on average nucleotide identity was 87.50 % when comparing GSTT-20T to V. paradoxus. Based on these results, the strain represented a novel species for which the name Variovorax durovernensis sp. nov. was proposed. The type strain is GSTT-20T (NCTC 14621T=CECT 30390T).
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Affiliation(s)
- Adela Alcolea-Medina
- Department of Infectious Diseases, King's College London, London, UK
- Infection Sciences, Synnovis, London, UK
| | - Luke B Snell
- Department of Infectious Diseases, King's College London, London, UK
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Lara Payne
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Christopher J Alder
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Jake D Turnbull
- The National Collection of Type Cultures, United Kingdom Health Security Agency, Colindale, London, UK
| | - Themoula Charalampous
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Lisa Bryan
- Infection Sciences, Synnovis, London, UK
| | - John L Klein
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Jonathan D Edgeworth
- Department of Infectious Diseases, King's College London, London, UK
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Rahul Batra
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
| | - Anna L Goodman
- Department of Infectious Diseases, King's College London, London, UK
- Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust, London, UK
- Medical Research Council Clinical Trials Unit, University College London, London, UK
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Vasilieva S, Lukyanov A, Antipova C, Grigoriev T, Lobakova E, Chivkunova O, Scherbakov P, Zaytsev P, Gorelova O, Fedorenko T, Kochkin D, Solovchenko A. Interactive Effects of Ceftriaxone and Chitosan Immobilization on the Production of Arachidonic Acid by and the Microbiome of the Chlorophyte Lobosphaera sp. IPPAS C-2047. Int J Mol Sci 2023; 24:10988. [PMID: 37446166 PMCID: PMC10341515 DOI: 10.3390/ijms241310988] [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: 05/29/2023] [Revised: 06/24/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Pharmaceuticals including antibiotics are among the hazardous micropollutants (HMP) of the environment. Incomplete degradation of the HMP leads to their persistence in water bodies causing a plethora of deleterious effects. Conventional wastewater treatment cannot remove HMP completely and a promising alternative comprises biotechnologies based on microalgae. The use of immobilized microalgae in environmental biotechnology is advantageous since immobilized cultures allow the recycling of the microalgal cells, support higher cell densities, and boost tolerance of microalgae to stresses including HMP. Here, we report on a comparative study of HMP (exemplified by the antibiotic ceftriaxone, CTA) removal by suspended and chitosan-immobilized cells of Lobosphaera sp. IPPAS C-2047 in flasks and in a column bioreactor. The removal of CTA added in the concentration of 20 mg/L was as high as 65% (in the flasks) or 85% (in the bioreactor). The adsorption on the carrier and abiotic oxidation were the main processes contributing 65-70% to the total CTA removal, while both suspended and immobilized cells took up 25-30% of CTA. Neither the immobilization nor CTA affected the accumulation of arachidonic acid (ARA) by Lobosphaera sp. during bioreactor tests but the subsequent nitrogen deprivation increased ARA accumulation 2.5 and 1.7 times in the suspended and chitosan-immobilized microalgae, respectively. The study of the Lobosphaera sp. microbiome revealed that the immobilization of chitosan rather than the CTA exposure was the main factor displacing the taxonomic composition of the microbiome. The possibility and limitations of the use of chitosan-immobilized Lobosphaera sp. IPPAS C-2047 for HMP removal coupled with the production of valuable long-chain polyunsaturated fatty acids is discussed.
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Affiliation(s)
- Svetlana Vasilieva
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
- Institute of Natural Sciences, Derzhavin Tambov State University, Komsomolskaya Square 5, 392008 Tambov, Russia
| | - Alexandr Lukyanov
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
| | - Christina Antipova
- Laboratory of Polymeric Materials, National Research Center “Kurchatov Institute”, Kurchatov Square 1, 123098 Moscow, Russia; (C.A.); (T.G.)
| | - Timofei Grigoriev
- Laboratory of Polymeric Materials, National Research Center “Kurchatov Institute”, Kurchatov Square 1, 123098 Moscow, Russia; (C.A.); (T.G.)
| | - Elena Lobakova
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
- Institute of Natural Sciences, Derzhavin Tambov State University, Komsomolskaya Square 5, 392008 Tambov, Russia
| | - Olga Chivkunova
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
| | - Pavel Scherbakov
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
| | - Petr Zaytsev
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
- Institute of Natural Sciences, Derzhavin Tambov State University, Komsomolskaya Square 5, 392008 Tambov, Russia
| | - Olga Gorelova
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
| | - Tatiana Fedorenko
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
| | - Dmitry Kochkin
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, 127276 Moscow, Russia
| | - Alexei Solovchenko
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia; (S.V.); (A.L.); (E.L.); (O.C.); (P.S.); (P.Z.); (O.G.); (T.F.); (D.K.)
- Institute of Natural Sciences, Derzhavin Tambov State University, Komsomolskaya Square 5, 392008 Tambov, Russia
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Xia M, Yu D, Chen H, Dai J, Gao N, Li S, Bi X, Qiu D. An RpoN-dependent PEP-CTERM gene is involved in floc formation of an Aquincola tertiaricarbonis strain. BMC Microbiol 2023; 23:20. [PMID: 36658495 PMCID: PMC9850573 DOI: 10.1186/s12866-022-02745-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 12/21/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The floc is a characteristic of microbial aggregate growth, displaying cloudy suspensions in water. Floc formation has been demonstrated in a series of bacteria and the floc-forming bacteria play a crucial role in activated sludge (AS) process widely used for municipal sewage and industrial wastewater treatment over a century. It has been demonstrated that some exopolysaccharide biosynthesis genes and the sigma factor (sigma54 or rpoN) were required for floc forming in some bacteria. However, the mechanism underlying the floc formation stills need to be elucidated. RESULTS In this study, we demonstrate that a TPR (Tetratricopeptide repeats) protein-encoding gene prsT is required for floc formation of Aquincola tertiaricarbonis RN12 and an upstream PEP-CTERM gene (designated pepA), regulated by RpoN1, is involved in its floc formation but not swarming motility and biofilm formation. Overexpression of PepA could rescue the floc-forming phenotype of the rpoN1 mutant by decreasing the released soluble exopolysaccharides and increasing the bound polymers. CONCLUSION Our results indicate that the wide-spread PEP-CTERM proteins play an important role in the self-flocculation of bacterial cells and may be a component of extracellular polymeric substances required for floc-formation.
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Affiliation(s)
- Ming Xia
- grid.411854.d0000 0001 0709 0000School of Life Sciences, Hubei Engineering Research Center for Protection and Utilization of Special Biological Resources in the Hanjiang River Basin, Jianghan University, Wuhan, 430056 China ,grid.411854.d0000 0001 0709 0000Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Jianghan University, Wuhan, 430056 China
| | - Dianzhen Yu
- grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China ,grid.419092.70000 0004 0467 2285Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Han Chen
- grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China ,grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Jingcheng Dai
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Na Gao
- grid.469521.d0000 0004 1756 0127Fisheries Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031 China
| | - Shuyang Li
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
| | - Xuezhi Bi
- grid.452198.30000 0004 0485 9218Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, 138668 Singapore
| | - Dongru Qiu
- grid.429211.d0000 0004 1792 6029Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei Province China
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Metaproteomic Analysis of an Oral Squamous Cell Carcinoma Dataset Suggests Diagnostic Potential of the Mycobiome. Int J Mol Sci 2023; 24:ijms24021050. [PMID: 36674563 PMCID: PMC9865486 DOI: 10.3390/ijms24021050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/16/2022] [Accepted: 12/23/2022] [Indexed: 01/07/2023] Open
Abstract
Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, with an estimated 5-year survival rate of only 40-50%, largely due to late detection and diagnosis. Emerging evidence suggests that the human microbiome may be implicated in OSCC, with oral microbiome studies putatively identifying relevant bacterial species. As the impact of other microbial organisms, such as fungi and viruses, has largely been neglected, a bioinformatic approach utilizing the Trans-Proteomic Pipeline (TPP) and the R statistical programming language was implemented here to investigate not only bacteria, but also viruses and fungi in the context of a publicly available, OSCC, mass spectrometry (MS) dataset. Overall viral, bacterial, and fungal composition was inferred in control and OSCC patient tissue from protein data, with a range of proteins observed to be differentially enriched between healthy and OSCC conditions, of which the fungal protein profile presented as the best potential discriminator of OSCC within the analysed dataset. While the current project sheds new light on the fungal and viral spheres of the oral microbiome in cancer in silico, further research will be required to validate these findings in an experimental setting.
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Schäfer L, Mikowsky N, Meinert-Berning C, Steinbüchel A. Unveiling steps of the TDP degradation pathway in Variovorax paradoxus TBEA6. Enzyme Microb Technol 2022; 160:110095. [PMID: 35810625 DOI: 10.1016/j.enzmictec.2022.110095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/03/2022]
Abstract
Since the role of biobased plastics increases every year, the search for alternatives to petrol-based polymers is very important. Variovorax paradoxus TBEA6 is able to grow with 3,3'-thiodipropionic acid (TDP) as sole source for carbon and energy. TDP can be used as a precursor substrate for the synthesis of polythioesters (PTE). To increase the feasibility of PTE synthesis, a good understanding of the degradation pathway of TDP in V. paradoxus TBEA6 is essential. Therefore, two putative 3-hydroxyisobutyryl-CoA hydrolases (VPARA_03110 & VPARA_05510) and two putative 3-hydroxypropionate dehydrogenases (VPARA_41140 & VPARA_54550) were investigated in this study. The deletion mutant V. paradoxus ∆VPARA_05510 showed a TDP-negative phenotype during growth experiments. The ability to grow with TDP as sole carbon source was successfully restored by complementation. Supernatant analysis revealed that the deletion mutant did not metabolize TDP or 3MP anymore. A specific enzyme activity up to 0.032 U/mg for the purified 3-hydroxyisobutyryl-CoA hydrolase VPARA_05510 was determined. A shift in the proteins (VPARA_54550) melting temperature of 6 °C with 2000 µM 3HP in comparison to protein without ligand was observed during thermal shift assays with the putative 3-hydroxypropionate dehydrogenase.
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Affiliation(s)
- Lukas Schäfer
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Nadine Mikowsky
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Christina Meinert-Berning
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany; Environmental Sciences Department, King Abdulaziz University, Jeddah, Saudi Arabia.
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6
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Fredendall RJ, Stone JL, Pehl MJ, Orwin PM. Transcriptome profiling of Variovorax paradoxus EPS under different growth conditions reveals regulatory and structural novelty in biofilm formation. Access Microbiol 2020; 2:acmi000121. [PMID: 32974586 PMCID: PMC7494200 DOI: 10.1099/acmi.0.000121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
We used transcriptome analysis by paired-end strand-specific RNA-seq to evaluate the specific changes in gene expression associated with the transition to static biofilm growth in the rhizosphere plant growth-promoting bacterium Variovorax paradoxus EPS. Triplicate biological samples of exponential growth, stationary phase and static biofilm samples were examined. DESeq2 and Rockhopper were used to identify robust and widespread shifts in gene expression specific to each growth phase. We identified 1711 protein-coding genes (28%) using DESeq2 that had altered expression greater than twofold specifically in biofilms compared to exponential growth. Fewer genes were specifically differentially expressed in stationary-phase culture (757, 12%). A small set of genes (103/6020) were differentially expressed in opposing fashions in biofilm and stationary phase, indicating potentially substantial shifts in phenotype. Gene-ontology analysis showed that the only class of genes specifically upregulated in biofilms was associated with nutrient transport, highlighting the importance of nutrient uptake in the biofilm. The biofilm-specific genes did not overlap substantially with the loci identified by mutagenesis studies, although some were present in both sets. The most highly upregulated biofilm-specific gene is predicted to be a part of the RNA degradosome, which indicates that RNA stability is used to regulate the biofilm phenotype. Two small putative proteins, Varpa_0407 and Varpa_3832, are highly expressed specifically in biofilms and are predicted to be secreted DNA-binding proteins, which may stabilize extracellular DNA as a component of the biofilm matrix. An flp/tad type-IV pilus locus (Varpa_5148-60) is strongly downregulated specifically in biofilms, in contrast with results from other systems for these pili. Mutagenesis confirms that this locus is important in surface motility rather than biofilm formation. These experimental results suggest that V. paradoxus EPS biofilms have substantial regulatory and structural novelty.
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Affiliation(s)
- Richard J. Fredendall
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Jenny L. Stone
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Michael J. Pehl
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Paul M. Orwin
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
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Dawson RA, Larke-Mejía NL, Crombie AT, Ul Haque MF, Murrell JC. Isoprene Oxidation by the Gram-Negative Model bacterium Variovorax sp. WS11. Microorganisms 2020; 8:E349. [PMID: 32121431 PMCID: PMC7143210 DOI: 10.3390/microorganisms8030349] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 01/19/2023] Open
Abstract
Plant-produced isoprene (2-methyl-1,3-butadiene) represents a significant portion of global volatile organic compound production, equaled only by methane. A metabolic pathway for the degradation of isoprene was first described for the Gram-positive bacterium Rhodococcus sp. AD45, and an alternative model organism has yet to be characterised. Here, we report the characterisation of a novel Gram-negative isoprene-degrading bacterium, Variovorax sp. WS11. Isoprene metabolism in this bacterium involves a plasmid-encoded iso metabolic gene cluster which differs from that found in Rhodococcus sp. AD45 in terms of organisation and regulation. Expression of iso metabolic genes is significantly upregulated by both isoprene and epoxyisoprene. The enzyme responsible for the initial oxidation of isoprene, isoprene monooxygenase, oxidises a wide range of alkene substrates in a manner which is strongly influenced by the presence of alkyl side-chains and differs from other well-characterised soluble diiron monooxygenases according to its response to alkyne inhibitors. This study presents Variovorax sp. WS11 as both a comparative and contrasting model organism for the study of isoprene metabolism in bacteria, aiding our understanding of the conservation of this biochemical pathway across diverse ecological niches.
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Affiliation(s)
- Robin A. Dawson
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
| | - Nasmille L. Larke-Mejía
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
| | - Andrew T. Crombie
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK;
| | - Muhammad Farhan Ul Haque
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54000, Pakistan;
| | - J. Colin Murrell
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
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Samuels T, Pybus D, Cockell CS. Casamino acids slow motility and stimulate surface growth in an extreme oligotroph. ENVIRONMENTAL MICROBIOLOGY REPORTS 2020; 12:63-69. [PMID: 31769203 DOI: 10.1111/1758-2229.12812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Environmental cues that regulate motility are poorly understood, but specific carbon and nitrogen sources, such as casamino acids (CAA), are known to stimulate motility in model organisms. However, natural environments are commonly more nutrient-limited than laboratory growth media, and the effect of energy-rich CAA on the motility of oligotrophic microorganisms is unknown. In this study, an extreme oligocarbotroph, Variovorax paradoxus YC1, was isolated from weathered shale rock within a disused mine level in North Yorkshire, UK. The addition of 0.1% CAA to minimal media significantly reduced the motility of YC1 after 72 h and inhibited swimming motility resulting in enhanced surface growth. We propose this response to CAA is a physiological adaptation to oligotrophy, facilitating the colonization of nutrient-rich environments.
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Affiliation(s)
- Toby Samuels
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - David Pybus
- ICL Boulby, Boulby Mine, Cleveland, TS13 4UZ, UK
| | - Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
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Zhang QQ, Zhang YH, Cai FY, Liu XL, Chen XH, Jiang M. Comparative antibacterial and antibiofilm activities of garlic extracts, nisin, ε‐polylysine, and citric acid on
Bacillus subtilis. J FOOD PROCESS PRES 2019. [DOI: 10.1111/jfpp.14179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Qiu Qin Zhang
- College of Food Science and Technology Nanjing Agricultural University Nanjing P.R. China
| | - Yu Hui Zhang
- College of Food Science and Technology Nanjing Agricultural University Nanjing P.R. China
| | - Fang Yuan Cai
- College of Food Science and Technology Nanjing Agricultural University Nanjing P.R. China
| | - Xiao Li Liu
- Institute of Agro‐product Processing Jiangsu Academy of Agricultural Sciences Nanjing P.R. China
| | - Xiao Hong Chen
- College of Food Science and Technology Nanjing Agricultural University Nanjing P.R. China
| | - Mei Jiang
- College of Food Science and Technology Nanjing Agricultural University Nanjing P.R. China
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10
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Microbial Community Composition and Antibiotic Resistance Genes within a North Carolina Urban Water System. WATER 2018. [DOI: 10.3390/w10111539] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Wastewater treatment plants (WWTPs) are thought to be potential incubators of antibiotic resistance. Persistence of commonly used antibiotics in wastewater may increase the potential for selection of resistance genes transferred between bacterial populations, some of which might pose a threat to human health. In this study, we measured the concentrations of ten antibiotics in wastewater plant influents and effluents, and in surface waters up- and downstream from two Charlotte area treatment facilities. We performed Illumina shotgun sequencing to assay the microbial community and resistome compositions at each site across four time points from late winter to mid-summer of 2016. Antibiotics are present throughout wastewater treatment, and elevated concentrations of multiple antibiotics are maintained in moving stream water downstream of effluent release. While some human gut and activated sludge associated taxa are detectable downstream, these seem to attenuate with distance while the core microbial community of the stream remains fairly consistent. We observe the slight suppression of functional pathways in the downstream microbial communities, including amino acid, carbohydrate, and nucleic acid metabolism, as well as nucleotide and amino acid scavenging. Nearly all antibiotic resistance genes (ARGs) and potentially pathogenic taxa are removed in the treatment process, though a few ARG markers are elevated downstream of effluent release. Taken together, these results represent baseline measurements that future studies can utilize to help to determine which factors control the movement of antibiotics and resistance genes through aquatic urban ecosystems before, during, and after wastewater treatment.
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11
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Ciok A, Budzik K, Zdanowski MK, Gawor J, Grzesiak J, Decewicz P, Gromadka R, Bartosik D, Dziewit L. Plasmids of Psychrotolerant Polaromonas spp. Isolated From Arctic and Antarctic Glaciers - Diversity and Role in Adaptation to Polar Environments. Front Microbiol 2018; 9:1285. [PMID: 29967598 PMCID: PMC6015842 DOI: 10.3389/fmicb.2018.01285] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/25/2018] [Indexed: 12/23/2022] Open
Abstract
Cold-active bacteria of the genus Polaromonas (class Betaproteobacteria) are important components of glacial microbiomes. In this study, extrachromosomal replicons of 26 psychrotolerant Polaromonas strains, isolated from Arctic and Antarctic glaciers, were identified, sequenced, and characterized. The plasmidome of these strains consists of 13 replicons, ranging in size from 3,378 to 101,077 bp. In silico sequence analyses identified the conserved backbones of these plasmids, composed of genes required for plasmid replication, stable maintenance, and conjugal transfer. Host range analysis revealed that all of the identified plasmids are narrow-host-range replicons, only able to replicate in bacteria of closely related genera (Polaromonas and Variovorax) of the Comamonadaceae family. Special attention was paid to the identification of plasmid auxiliary genetic information, which may contribute to the adaptation of bacteria to environmental conditions occurring in glaciers. Detailed analysis revealed the presence of genes encoding proteins potentially involved in (i) protection against reactive oxygen species, ultraviolet radiation, and low temperatures; (ii) transport and metabolism of organic compounds; (iii) transport of metal ions; and (iv) resistance to heavy metals. Some of the plasmids also carry genes required for the molecular assembly of iron-sulfur [Fe-S] clusters. Functional analysis of the predicted heavy metal resistance determinants demonstrated that their activity varies, depending on the host strain. This study provides the first molecular insight into the mobile DNA of Polaromonas spp. inhabiting polar glaciers. It has generated valuable data on the structure and properties of a pool of plasmids and highlighted their role in the biology of psychrotolerant Polaromonas strains and their adaptation to the environmental conditions of Arctic and Antarctic glaciers.
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Affiliation(s)
- Anna Ciok
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Karol Budzik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Marek K. Zdanowski
- Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Jan Gawor
- Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Jakub Grzesiak
- Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Przemyslaw Decewicz
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Robert Gromadka
- Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Dariusz Bartosik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Lukasz Dziewit
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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Chakroun I, Mahdhi A, Morcillo P, Cordero H, Cuesta A, Bakhrouf A, Mahdouani K, Esteban MÁ. Motility, biofilm formation, apoptotic effect and virulence gene expression of atypical Salmonella Typhimurium outside and inside Caco-2 cells. Microb Pathog 2018; 114:153-162. [DOI: 10.1016/j.micpath.2017.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/04/2017] [Accepted: 11/09/2017] [Indexed: 12/15/2022]
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RpoN (σ 54) Is Required for Floc Formation but Not for Extracellular Polysaccharide Biosynthesis in a Floc-Forming Aquincola tertiaricarbonis Strain. Appl Environ Microbiol 2017; 83:AEM.00709-17. [PMID: 28500044 DOI: 10.1128/aem.00709-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 05/08/2017] [Indexed: 11/20/2022] Open
Abstract
Some bacteria are capable of forming flocs, in which bacterial cells become self-flocculated by secreted extracellular polysaccharides and other biopolymers. The floc-forming bacteria play a central role in activated sludge, which has been widely utilized for the treatment of municipal sewage and industrial wastewater. Here, we use a floc-forming bacterium, Aquincolatertiaricarbonis RN12, as a model to explore the biosynthesis of extracellular polysaccharides and the regulation of floc formation. A large gene cluster for exopolysaccharide biosynthesis and a gene encoding the alternative sigma factor RpoN1, one of the four paralogues, have been identified in floc formation-deficient mutants generated by transposon mutagenesis, and the gene functions have been further confirmed by genetic complementation analyses. Interestingly, the biosynthesis of exopolysaccharides remained in the rpoN1-disrupted flocculation-defective mutants, but most of the exopolysaccharides were secreted and released rather than bound to the cells. Furthermore, the expression of exopolysaccharide biosynthesis genes seemed not to be regulated by RpoN1. Taken together, our results indicate that RpoN1 may play a role in regulating the expression of a certain gene(s) involved in the self-flocculation of bacterial cells but not in the biosynthesis and secretion of exopolysaccharides required for floc formation.IMPORTANCE Floc formation confers bacterial resistance to predation of protozoa and plays a central role in the widely used activated sludge process. In this study, we not only identified a large gene cluster for biosynthesis of extracellular polysaccharides but also identified four rpoN paralogues, one of which (rpoN1) is required for floc formation in A. tertiaricarbonis RN12. In addition, this RpoN sigma factor regulates the transcription of genes involved in biofilm formation and swarming motility, as previously shown in other bacteria. However, this RpoN paralogue is not required for the biosynthesis of exopolysaccharides, which are released and dissolved into culture broth by the rpoN1 mutant rather than remaining tightly bound to cells, as observed during the flocculation of the wild-type strain. These results indicate that floc formation is a regulated complex process, and other yet-to-be identified RpoN1-dependent factors are involved in self-flocculation of bacterial cells via exopolysaccharides and/or other biopolymers.
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Steffens T, Vorhölter FJ, Giampà M, Hublik G, Pühler A, Niehaus K. The influence of a modified lipopolysaccharide O-antigen on the biosynthesis of xanthan in Xanthomonas campestris pv. campestris B100. BMC Microbiol 2016; 16:93. [PMID: 27215401 PMCID: PMC4878081 DOI: 10.1186/s12866-016-0710-y] [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: 12/17/2015] [Accepted: 05/13/2016] [Indexed: 12/03/2022] Open
Abstract
Background The exopolysaccharide xanthan is a natural product which is extensively used in industry. It is a thickening agent in many fields, from oil recovery to the food sector. Xanthan is produced by the Gram negative bacterium Xanthomonas campestris pv. campestris (Xcc). We analyzed the lipopolysaccharide (LPS) of three mutant strains of the Xcc wild type B100 to distinguish if the xanthan production can be increased when LPS biosynthesis is affected. Results The Xcc B100 O-antigen (OA) is composed of a linear main chain of rhamnose residues with N-acetylfucosamine (FucNAc) side branches at every second rhamnose. It is the major LPS constituent. The O-antigen was missing completely in the mutant strain H21012 (deficient in wxcB), since neither rhamnose nor FucNAc could be detected as part of the LPS by MALDI-TOF-MS, and only a slight amount of rhamnose and no FucNAc was found by GC analysis. The LPS of two other mutants was analyzed, Xcc H28110 (deficient in wxcK) and H20110 (wxcN). In both of them no FucNAc could be detected in the LPS fraction, while the rhamnose moieties were more abundant than in wild type LPS. The measurements were carried out by GC and confirmed by MALDI-TOF-MS analyses that indicated an altered OA in which the branches are missing, while the rhamnan main chain seemed longer than in the wild type. Quantification of xanthan confirmed our hypothesis that a missing OA can lead to an increased production of the extracellular polysaccharide. About 6.3 g xanthan per g biomass were produced by the Xcc mutant H21012 (wxcB), as compared to the wild type production of approximately 5 g xanthan per g biomass. In the two mutant strains with modified OA however, Xcc H28110 (wxcK) and Xcc H20110 (wxcN), the xanthan production of 5.5 g and 5.3 g, respectively, was not significantly increased. Conclusions Mutations affecting LPS biosynthesis can be beneficial for the production of the extracellular polysaccharide xanthan. However, only complete inhibition of the OA resulted in increased xanthan production. The inhibition of the FucNAc side branches did not lead to increased production, but provoked a novel LPS phenotype. The data suggests an elongation of the linear rhamnan main chain of the LPS OA in both the Xcc H28110 (wxcK) and Xcc H20110 (wxcN) mutant strains. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0710-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tim Steffens
- Proteom- und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany.,Genomforschung industrieller Mikroorganismen, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany
| | - Frank-Jörg Vorhölter
- Proteom- und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany.,Genomforschung industrieller Mikroorganismen, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany.,Present address: MVZ Dr. Eberhard & Partner, Brauhausstr. 4, 44137, Dortmund, Germany
| | - Marco Giampà
- Proteom- und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany
| | - Gerd Hublik
- Jungbunzlauer Austria AG, Pernhofen 1, 2064, Wulzeshofen, Austria
| | - Alfred Pühler
- Genomforschung industrieller Mikroorganismen, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany
| | - Karsten Niehaus
- Proteom- und Metabolomforschung, Fakultät für Biologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Universitätsstraße 27, 33615, Bielefeld, Germany.
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Ciok A, Dziewit L, Grzesiak J, Budzik K, Gorniak D, Zdanowski MK, Bartosik D. Identification of miniature plasmids in psychrophilic Arctic bacteria of the genus Variovorax. FEMS Microbiol Ecol 2016; 92:fiw043. [PMID: 26917781 DOI: 10.1093/femsec/fiw043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2016] [Indexed: 11/13/2022] Open
Abstract
The Svalbard archipelago (Spitsbergen Island) is the northernmost landmass in the European Arctic and has a variety of small- and medium-sized glaciers. The plasmidome of eleven psychrophilic strains of Variovorax spp. isolated from the ice surface of Hans and Werenskiold Glaciers of Spitsbergen Island, was defined. This analysis revealed the presence of six plasmids whose nucleotide sequences have been determined. Four of them, exhibiting high reciprocal sequence similarity, possess unique structures, since their genomes lack any recognized genes. These miniature replicons, not exceeding 1 kb in size, include pHW69V1 (746 bp), which is the smallest autonomous replicon so far identified in free-living bacteria. The miniature plasmids share no similarity with known sequences present in the databases. In silico and experimental analyses identified conserved DNA regions essential for the initiation of replication of these replicons.
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Affiliation(s)
- Anna Ciok
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Lukasz Dziewit
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jakub Grzesiak
- Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Karol Budzik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Dorota Gorniak
- Department of Microbiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland
| | - Marek K Zdanowski
- Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Dariusz Bartosik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
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Functional and proteomic analyses reveal that wxcB is involved in virulence, motility, detergent tolerance, and biofilm formation in Xanthomonas campestris pv. vesicatoria. Biochem Biophys Res Commun 2014; 452:389-94. [DOI: 10.1016/j.bbrc.2014.08.076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 08/16/2014] [Indexed: 11/23/2022]
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17
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Kalai Chelvam K, Chai LC, Thong KL. Variations in motility and biofilm formation of Salmonella enterica serovar Typhi. Gut Pathog 2014; 6:2. [PMID: 24499680 PMCID: PMC3922113 DOI: 10.1186/1757-4749-6-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/28/2014] [Indexed: 01/02/2023] Open
Abstract
Background Salmonella enterica serovar Typhi (S. Typhi) exhibits unique characteristics as an intracellular human pathogen. It causes both acute and chronic infection with various disease manifestations in the human host only. The principal factors underlying the unique lifestyle of motility and biofilm forming ability of S. Typhi remain largely unknown. The main objective of this study was to explore and investigate the motility and biofilm forming behaviour among S. Typhi strains of diverse background. Results Swim and swarm motility tests were performed with 0.25% and 0.5% agar concentration, respectively; while biofilm formation was determined by growing the bacterial cultures for 48 hrs in 96-well microtitre plate. While all S. Typhi strains demonstrated swarming motility with smooth featureless morphology, 58 out of 60 strains demonstrated swimming motility with featureless or bull’s eye morphology. Interestingly, S. Typhi strains of blood-borne origin exhibited significantly higher swimming motility (P < 0.05) than stool-borne strains suggesting that swimming motility may play a role in the systemic invasion of S. Typhi in the human host. Also, stool-borne S. Typhi displayed a negative relationship between motility and biofilm forming behaviour, which was not observed in the blood-borne strains. Conclusion In summary, both swimming and swarming motility are conserved among S. Typhi strains but there was variation for biofilm forming ability. There was no difference observed in this phenotype for S. Typhi strains from diverse background. These findings serve as caveats for future studies to understand the lifestyle and transmission of this pathogen.
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Affiliation(s)
| | | | - Kwai Lin Thong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
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Brandt U, Hiessl S, Schuldes J, Thürmer A, Wübbeler JH, Daniel R, Steinbüchel A. Genome-guided insights into the versatile metabolic capabilities of the mercaptosuccinate-utilizing β-proteobacterium Variovorax paradoxus strain B4. Environ Microbiol 2013; 16:3370-86. [PMID: 24245581 DOI: 10.1111/1462-2920.12340] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
Abstract
Variovorax paradoxus B4 is able to utilize 2-mercaptosuccinate (MS) as sole carbon, sulfur and energy source. The whole genome of V. paradoxus B4 was sequenced, annotated and evaluated with special focus on genomic elements related to MS metabolism. The genome encodes two chromosomes harbouring 5 795 261 and 1 353 255 bp. A total of 6753 putative protein-coding sequences were identified. Based on the genome and in combination with results from previous studies, a putative pathway for the degradation of MS could be postulated. The putative molybdopterin oxidoreductase identified during transposon mutagenesis probably catalyses the conversion of MS first into sulfinosuccinate and then into sulfosuccinate by successive transfer of oxygen atoms. Subsequently, the cleavage of sulfosuccinate yields oxaloacetate and sulfite, while the latter is oxidized to sulfate. The expression of the putative molybdopterin oxidoreductase was induced by MS, but not by gluconate, as confirmed by reverse transcriptase polymerase chain reaction. Further, in silico studies combined with experiments and comparative genomics revealed high metabolic diversity of strain B4. It bears a high potential as plant growth-promoting bacterium and as candidate for degradation and detoxification of xenobiotics and other hardly degradable substances. Additionally, the strain is of special interest for production of polythioesters with sulfur-containing precursors as MS.
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Affiliation(s)
- Ulrike Brandt
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Corrensstraße 3, Münster, D-48149, Germany
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Abstract
Type IV pili (T4P) are multifunctional protein fibers produced on the surfaces of a wide variety of bacteria and archaea. The major subunit of T4P is the type IV pilin, and structurally related proteins are found as components of the type II secretion (T2S) system, where they are called pseudopilins; of DNA uptake/competence systems in both Gram-negative and Gram-positive species; and of flagella, pili, and sugar-binding systems in the archaea. This broad distribution of a single protein family implies both a common evolutionary origin and a highly adaptable functional plan. The type IV pilin is a remarkably versatile architectural module that has been adopted widely for a variety of functions, including motility, attachment to chemically diverse surfaces, electrical conductance, acquisition of DNA, and secretion of a broad range of structurally distinct protein substrates. In this review, we consider recent advances in this research area, from structural revelations to insights into diversity, posttranslational modifications, regulation, and function.
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Genome of the Root-Associated Plant Growth-Promoting Bacterium Variovorax paradoxus Strain EPS. GENOME ANNOUNCEMENTS 2013; 1:1/5/e00843-13. [PMID: 24158554 PMCID: PMC3813184 DOI: 10.1128/genomea.00843-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Variovorax paradoxus is a ubiquitous betaproteobacterium involved in plant growth promotion, the degradation of xenobiotics, and quorum-quenching activity. The genome of V. paradoxus strain EPS consists of a single circular chromosome of 6,550,056 bp, with a 66.48% G+C content.
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Carzaniga T, Antoniani D, Dehò G, Briani F, Landini P. The RNA processing enzyme polynucleotide phosphorylase negatively controls biofilm formation by repressing poly-N-acetylglucosamine (PNAG) production in Escherichia coli C. BMC Microbiol 2012; 12:270. [PMID: 23171129 PMCID: PMC3571907 DOI: 10.1186/1471-2180-12-270] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/01/2012] [Indexed: 08/05/2024] Open
Abstract
Background Transition from planktonic cells to biofilm is mediated by production of adhesion factors, such as extracellular polysaccharides (EPS), and modulated by complex regulatory networks that, in addition to controlling production of adhesion factors, redirect bacterial cell metabolism to the biofilm mode. Results Deletion of the pnp gene, encoding polynucleotide phosphorylase, an RNA processing enzyme and a component of the RNA degradosome, results in increased biofilm formation in Escherichia coli. This effect is particularly pronounced in the E. coli strain C-1a, in which deletion of the pnp gene leads to strong cell aggregation in liquid medium. Cell aggregation is dependent on the EPS poly-N-acetylglucosamine (PNAG), thus suggesting negative regulation of the PNAG biosynthetic operon pgaABCD by PNPase. Indeed, pgaABCD transcript levels are higher in the pnp mutant. Negative control of pgaABCD expression by PNPase takes place at mRNA stability level and involves the 5’-untranslated region of the pgaABCD transcript, which serves as a cis-element regulating pgaABCD transcript stability and translatability. Conclusions Our results demonstrate that PNPase is necessary to maintain bacterial cells in the planktonic mode through down-regulation of pgaABCD expression and PNAG production.
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Affiliation(s)
- Thomas Carzaniga
- Department of Biosciences, University of Milan, Via Celoria 26, Milan, 20133, Italy
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