1
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Möller C, Sharma R, Öz R, Reginato G, Cannavo E, Ceppi I, Sriram KK, Cejka P, Westerlund F. Xrs2/NBS1 promote end-bridging activity of the MRE11-RAD50 complex. Biochem Biophys Res Commun 2024; 695:149464. [PMID: 38217957 DOI: 10.1016/j.bbrc.2023.149464] [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: 10/10/2023] [Revised: 12/04/2023] [Accepted: 12/29/2023] [Indexed: 01/15/2024]
Abstract
DNA double strand breaks (DSBs) can be detrimental to the cell and need to be efficiently repaired. A first step in DSB repair is to bring the free ends in close proximity to enable ligation by non-homologous end-joining (NHEJ), while the more precise, but less available, repair by homologous recombination (HR) requires close proximity of a sister chromatid. The human MRE11-RAD50-NBS1 (MRN) complex, Mre11-Rad50-Xrs2 (MRX) in yeast, is involved in both repair pathways. Here we use nanofluidic channels to study, on the single DNA molecule level, how MRN, MRX and their constituents interact with long DNA and promote DNA bridging. Nanofluidics is a suitable method to study reactions on DNA ends since no anchoring of the DNA end(s) is required. We demonstrate that NBS1 and Xrs2 play important, but differing, roles in the DNA tethering by MRN and MRX. NBS1 promotes DNA bridging by MRN consistent with tethering of a repair template. MRX shows a "synapsis-like" DNA end-bridging, stimulated by the Xrs2 subunit. Our results highlight the different ways MRN and MRX bridge DNA, and the results are in agreement with their key roles in HR and NHEJ, respectively, and contribute to the understanding of the roles of NBS1 and Xrs2 in DSB repair.
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Affiliation(s)
- Carl Möller
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Rajhans Sharma
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Robin Öz
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Giordano Reginato
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - Elda Cannavo
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - K K Sriram
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Petr Cejka
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland
| | - Fredrik Westerlund
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden.
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2
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Kk S, Persson F, Fritzsche J, Beech JP, Tegenfeldt JO, Westerlund F. Fluorescence Microscopy of Nanochannel-Confined DNA. Methods Mol Biol 2024; 2694:175-202. [PMID: 37824005 DOI: 10.1007/978-1-0716-3377-9_9] [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: 10/13/2023]
Abstract
Stretching of DNA in nanoscale confinement allows for several important studies. The genetic contents of the DNA can be visualized on the single DNA molecule level, and the polymer physics of confined DNA and also DNA/protein and other DNA/DNA-binding molecule interactions can be explored. This chapter describes the basic steps to fabricate the nanostructures, perform the experiments, and analyze the data.
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Affiliation(s)
- Sriram Kk
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Joachim Fritzsche
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Jason P Beech
- NanoLund and Department of Physics, Lund University, Lund, Sweden
| | | | - Fredrik Westerlund
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden.
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3
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Wu J, Choi J, Uba FI, Soper SA, Park S. Engineering inlet structures to enhance DNA capture into nanochannels in a polymer nanofluidic device produced via nanoimprint lithography. MICRO AND NANO ENGINEERING 2023; 21:100230. [PMID: 38737190 PMCID: PMC11085012 DOI: 10.1016/j.mne.2023.100230] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Operating nanofluidic biosensors requires threading single molecules to be analyzed from microfluidic networks into nanostructures, mostly nanochannels or nanopores. Different inlet structures have been employed as a means of enhancing the number of the capture events into nanostructures. Here, we systematically investigated the effects of various engineered inlet structures formed at the micro/nanochannel interface on the capture of single λ-DNA molecules into the nanochannels. Different inlet geometries were evaluated and ranked in order of their effectiveness. Adding an inlet structure prior to a nanochannel effectively improved the DNA capture rate by 190 - 700 % relative to that for the abrupt micro/nanochannel interface. The capture of DNA from the microchannel to various inlets was determined mainly by the capture volumes of the inlet structures and the geometrically modified electric field in the inlet structure. However, as the width of the inlet structure increased, the hydrodynamic flow existing in the microchannel negatively influenced the DNA capture by dragging some DNA molecules deep into the inlet structure back to the microchannel. Our results indicate that engineering inlet structures is an effective means of controlling the capture of DNA molecules into nanostructures, which is important for operation of nanofluidic biosensors.
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Affiliation(s)
- Jiahao Wu
- Mechanical & Industrial Engineering Department, Louisiana State University, Baton Rouge, LA 70803, USA
- Center of BioModular Multiscale Systems for Precision Medicine, USA
| | - Junseo Choi
- Mechanical & Industrial Engineering Department, Louisiana State University, Baton Rouge, LA 70803, USA
- Center of BioModular Multiscale Systems for Precision Medicine, USA
| | - Franklin I. Uba
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
- Center of BioModular Multiscale Systems for Precision Medicine, USA
| | - Steven A. Soper
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
- Center of BioModular Multiscale Systems for Precision Medicine, USA
- Bioengineering Program, The University of Kansas, Lawrence, KS 66045, USA
- Department of Mechanical Engineering, The University of Kansas, Lawrence, KS 66045, USA
- KU Cancer Center, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sunggook Park
- Mechanical & Industrial Engineering Department, Louisiana State University, Baton Rouge, LA 70803, USA
- Center of BioModular Multiscale Systems for Precision Medicine, USA
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4
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Gautam D, Pandey S, Chen J. Effect of Flow Rate and Ionic Strength on the Stabilities of YOYO-1 and YO-PRO-1 Intercalated in DNA Molecules. J Phys Chem B 2023; 127:2450-2456. [PMID: 36917775 PMCID: PMC10088364 DOI: 10.1021/acs.jpcb.3c00777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Single-molecule DNA studies have improved our understanding of the DNAs' structure and their interactions with other molecules. A variety of DNA labeling dyes are available for single-molecule studies, among which the bis-intercalating dye YOYO-1 and mono-intercalating dye YO-PRO-1 are widely used. They have an extraordinarily strong affinity toward DNA and are bright with a high quantum yield (>0.5) when bound to DNAs. However, it is still not clear how these dyes behave in DNA molecules under higher ionic strength and strong buffer flow. Here, we have studied the effect of ionic strength and flow rate of buffer on their binding in single DNA molecules. The larger the flow rate and the higher the ionic strength, the faster the intercalated dyes are washed away from the DNAs. In the buffer with 1 M ionic strength, YOYO-1 and YO-PRO-1 are mostly washed away from DNA within 2 min of moderate buffer flow.
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Affiliation(s)
- Dinesh Gautam
- Department of Chemistry and Biochemistry, Nanoscale & Quantum Phenomena Institute, Ohio University, Athens, OH 45701, USA
| | - Srijana Pandey
- Department of Chemistry and Biochemistry, Nanoscale & Quantum Phenomena Institute, Ohio University, Athens, OH 45701, USA
| | - Jixin Chen
- Department of Chemistry and Biochemistry, Nanoscale & Quantum Phenomena Institute, Ohio University, Athens, OH 45701, USA
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5
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Faraji F, Neek-Amal M, Neyts EC, Peeters FM. Cation-controlled permeation of charged polymers through nanocapillaries. Phys Rev E 2023; 107:034501. [PMID: 37073056 DOI: 10.1103/physreve.107.034501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 02/28/2023] [Indexed: 04/20/2023]
Abstract
Molecular dynamics simulations are used to study the effects of different cations on the permeation of charged polymers through flat capillaries with heights below 2 nm. Interestingly, we found that, despite being monovalent, Li^{+}, Na^{+}, and K^{+} cations have different effects on polymer permeation, which consequently affects their transmission speed throughout those capillaries. We attribute this phenomenon to the interplay of the cations' hydration free energies and the hydrodynamic drag in front of the polymer when it enters the capillary. Different alkali cations exhibit different surface versus bulk preferences in small clusters of water under the influence of an external electric field. This paper presents a tool to control the speed of charged polymers in confined spaces using cations.
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Affiliation(s)
- Fahim Faraji
- PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
- Condensed Matter Theory, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Center of Excellence NANOlab, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Mehdi Neek-Amal
- Condensed Matter Theory, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Department of Physics, Shahid Rajaee Teacher Training University, 16875-163 Tehran, Iran
| | - Erik C Neyts
- PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
- Center of Excellence NANOlab, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - François M Peeters
- Condensed Matter Theory, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Center of Excellence NANOlab, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal do Ceará, Fortaleza-CE 60455-760, Brazil
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6
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Nyblom M, Johnning A, Frykholm K, Wrande M, Müller V, Goyal G, Robertsson M, Dvirnas A, Sewunet T, KK S, Ambjörnsson T, Giske CG, Sandegren L, Kristiansson E, Westerlund F. Strain-level bacterial typing directly from patient samples using optical DNA mapping. COMMUNICATIONS MEDICINE 2023; 3:31. [PMID: 36823379 PMCID: PMC9950433 DOI: 10.1038/s43856-023-00259-z] [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: 05/26/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Identification of pathogens is crucial to efficiently treat and prevent bacterial infections. However, existing diagnostic techniques are slow or have a too low resolution for well-informed clinical decisions. METHODS In this study, we have developed an optical DNA mapping-based method for strain-level bacterial typing and simultaneous plasmid characterisation. For the typing, different taxonomical resolutions were examined and cultivated pure Escherichia coli and Klebsiella pneumoniae samples were used for parameter optimization. Finally, the method was applied to mixed bacterial samples and uncultured urine samples from patients with urinary tract infections. RESULTS We demonstrate that optical DNA mapping of single DNA molecules can identify Escherichia coli and Klebsiella pneumoniae at the strain level directly from patient samples. At a taxonomic resolution corresponding to E. coli sequence type 131 and K. pneumoniae clonal complex 258 forming distinct groups, the average true positive prediction rates are 94% and 89%, respectively. The single-molecule aspect of the method enables us to identify multiple E. coli strains in polymicrobial samples. Furthermore, by targeting plasmid-borne antibiotic resistance genes with Cas9 restriction, we simultaneously identify the strain or subtype and characterize the corresponding plasmids. CONCLUSION The optical DNA mapping method is accurate and directly applicable to polymicrobial and clinical samples without cultivation. Hence, it has the potential to rapidly provide comprehensive diagnostics information, thereby optimizing early antibiotic treatment and opening up for future precision medicine management.
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Affiliation(s)
- My Nyblom
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Anna Johnning
- grid.5371.00000 0001 0775 6028Department of Mathematical Sciences, Chalmers University of Technology & University of Gothenburg, Gothenburg, 412 96 Sweden ,grid.452079.dDepartment of Systems and Data Analysis, Fraunhofer-Chalmers Centre, Gothenburg, 412 88 Sweden ,Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, 405 30 Sweden
| | - Karolin Frykholm
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Marie Wrande
- grid.8993.b0000 0004 1936 9457Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, 751 23 Sweden
| | - Vilhelm Müller
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Gaurav Goyal
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Miriam Robertsson
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Albertas Dvirnas
- grid.4514.40000 0001 0930 2361Department of Astronomy and Theoretical Physics, Lund University, Lund, 223 62 Sweden
| | - Tsegaye Sewunet
- grid.4714.60000 0004 1937 0626Department of Laboratory Medicine, Karolinska Institutet, Stockholm, 141 86 Sweden
| | - Sriram KK
- grid.5371.00000 0001 0775 6028Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96 Sweden
| | - Tobias Ambjörnsson
- grid.4514.40000 0001 0930 2361Department of Astronomy and Theoretical Physics, Lund University, Lund, 223 62 Sweden
| | - Christian G. Giske
- grid.4714.60000 0004 1937 0626Department of Laboratory Medicine, Karolinska Institutet, Stockholm, 141 86 Sweden ,grid.24381.3c0000 0000 9241 5705Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, 171 76 Sweden
| | - Linus Sandegren
- grid.8993.b0000 0004 1936 9457Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, 751 23 Sweden
| | - Erik Kristiansson
- Department of Mathematical Sciences, Chalmers University of Technology & University of Gothenburg, Gothenburg, 412 96, Sweden. .,Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, 405 30, Sweden.
| | - Fredrik Westerlund
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, 412 96, Sweden. .,Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, 405 30, Sweden.
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7
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Heo W, Seo J, Lee Y, Kim Y. Fluid-driven DNA stretching for single-molecule studies on chromatin-associated proteins. Biochem Biophys Res Commun 2022; 634:122-128. [DOI: 10.1016/j.bbrc.2022.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/05/2022] [Accepted: 10/05/2022] [Indexed: 11/28/2022]
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8
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Sewunet T, K. K. S, Nguyen HH, Sithivong N, Hoang NTB, Sychareun V, Nengmongvang K, Larsson M, Olson L, Westerlund F, Giske CG. Fecal carriage and clonal dissemination of blaNDM-1 carrying Klebsiella pneumoniae sequence type 147 at an intensive care unit in Lao PDR. PLoS One 2022; 17:e0274419. [PMID: 36194564 PMCID: PMC9531820 DOI: 10.1371/journal.pone.0274419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 08/29/2022] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVES Carbapenemase-producing Enterobacterales (CPE) are high priority targets of global antimicrobial surveillance. Herein, we determined the colonization rate of CPE on admission to intensive care units in Vientiane, Lao PDR in August-September 2019. METHODS Data regarding clinical conditions, infection control, and antibiotic usage were collected during admission. Rectal swab samples (n = 137) collected during admission were inoculated to selective chromogenic agars, followed by confirmatory tests for extended-spectrum beta-lactamases and carbapenemases. All CPE isolates were sequenced on Illumina (HiSeq2500), reads assembled using SPAdes 3.13, and the draft genomes used to query a database (https://www.genomicepidemiology.org) for resistome, plasmid replicons, and sequence types (ST). Optical DNA mapping (ODM) was used to characterize plasmids and to determine location of resistance genes. Minimum spanning tree was generated using the Bacterial Isolate Genome Sequence database (BIGSdb) and annotated using iTOL. RESULT From 47 Enterobacterales isolated on selective agars, K. pneumoniae (25/47) and E. coli (12/47) were the most prevalent species, followed by K aerogenes (2/47), K. variicola (1/47), and K. oxytoca (1/47). The overall prevalence of ESBLs was 51.0%; E. coli 83.3% (10/12) and Klebsiella spp. 41.3% (12/29). Twenty percent of the K. pneumoniae (5/25) isolates were carbapenem-resistant, and 4/5 contained the blaNDM-1 gene. All blaNDM-1 isolates belonged to ST147 and were indistinguishable with cgMLST. ODM showed that the blaNDM-1 gene was located on identical plasmids in all isolates. CONCLUSION The prevalence of ESBL-producing Enterobacterales was high, while carbapenemases were less common. However, the detection of clonal dissemination of blaNDM-1-producing K. pneumoniae isolates in one of the intensive care units calls for vigilance. Stringent infection prevention and antimicrobial stewardship strategies are highly important measures.
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Affiliation(s)
- Tsegaye Sewunet
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
| | - Sriram K. K.
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ha Hoang Nguyen
- Hanoi Medical University, Hanoi, Vietnam
- Training and Research Academic Collaboration (TRAC) Sweden, Vietnam
| | - Noikaseumsy Sithivong
- National Center for Laboratory and Epidemiology, Ministry of Health, Vientiane, Lao PDR
| | - Ngoc Thi Bich Hoang
- Department of Microbiology, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Vanphanom Sychareun
- Faculty of Postgraduate Studies, University of Health Sciences, Ministry of Health, Vientiane, Lao PDR
| | - Kokasia Nengmongvang
- Faculty of Postgraduate Studies, University of Health Sciences, Ministry of Health, Vientiane, Lao PDR
| | - Mattias Larsson
- Training and Research Academic Collaboration (TRAC) Sweden, Vietnam
- Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden
| | - Linus Olson
- Training and Research Academic Collaboration (TRAC) Sweden, Vietnam
- Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Christian G. Giske
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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9
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Esmek FM, Erichlandwehr T, Brkovic N, Pranzner NP, Teuber JP, Fernandez-Cuesta I. Pillar-structured 3D inlets fabricated by dose-modulated e-beam lithography and nanoimprinting for DNA analysis in passive, clogging-free, nanofluidic devices. NANOTECHNOLOGY 2022; 33:385301. [PMID: 35696945 DOI: 10.1088/1361-6528/ac780d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
We present the fabrication of three-dimensional inlets with gradually decreasing widths and depths and with nanopillars on the slope, all defined in just one lithography step. In addition, as an application, we show how these micro- and nanostructures can be used for micro- and nanofluidics and lab-on-a-chip devices to facilitate the flow and analyze single molecules of DNA. For the fabrication of 3D inlets in a single layer process, dose-modulated electron beam lithography was used, producing depths between 750 nm and 50 nm along a 30 μm long inlet, which is additionally structured with nanometer-scale pillars randomly distributed on top, as a result of incomplete exposure and underdevelopment of the resist. The fabrication conditions affect the slope of the inlet, the nanopillar density and coverage. The key parameters are the dose used for the electron beam exposure and the development conditions, like the developer's dilution, stirring and development time. The 3D inlets with nanostructured pillars were integrated into fluidic devices, acting as a transition between micro and nanofluidic structures for pre-stretching and unfolding DNA molecules, avoiding the intrusion of folded molecules and clogging the analysis channel. After patterning these structures in silicon, they can be replicated in polymer by UV nanoimprinting. We show here how the inlets with pillars slow down the molecules before they enter the nanochannels, resulting in a 3-fold decrease in speed, which would translate to an improvement in the resolution for DNA optical mapping.
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Affiliation(s)
- Franziska M Esmek
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Tim Erichlandwehr
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Nico Brkovic
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Nathalie P Pranzner
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Jeremy P Teuber
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Irene Fernandez-Cuesta
- Universität Hamburg, Institute of Nanostructure and Solid State Physics, HARBOR Bldg 610, Luruper Chaussee 149, Hamburg D-22761, Germany
- Hamburg Centre for Ultrafast Imaging, Germany
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10
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Dvirnas A, Stewart C, Müller V, Bikkarolla SK, Frykholm K, Sandegren L, Kristiansson E, Westerlund F, Ambjörnsson T. Detection of structural variations in densely-labelled optical DNA barcodes: A hidden Markov model approach. PLoS One 2021; 16:e0259670. [PMID: 34739528 PMCID: PMC8570516 DOI: 10.1371/journal.pone.0259670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/22/2021] [Indexed: 11/19/2022] Open
Abstract
Large-scale genomic alterations play an important role in disease, gene expression, and chromosome evolution. Optical DNA mapping (ODM), commonly categorized into sparsely-labelled ODM and densely-labelled ODM, provides sequence-specific continuous intensity profiles (DNA barcodes) along single DNA molecules and is a technique well-suited for detecting such alterations. For sparsely-labelled barcodes, the possibility to detect large genomic alterations has been investigated extensively, while densely-labelled barcodes have not received as much attention. In this work, we introduce HMMSV, a hidden Markov model (HMM) based algorithm for detecting structural variations (SVs) directly in densely-labelled barcodes without access to sequence information. We evaluate our approach using simulated data-sets with 5 different types of SVs, and combinations thereof, and demonstrate that the method reaches a true positive rate greater than 80% for randomly generated barcodes with single variations of size 25 kilobases (kb). Increasing the length of the SV further leads to larger true positive rates. For a real data-set with experimental barcodes on bacterial plasmids, we successfully detect matching barcode pairs and SVs without any particular assumption of the types of SVs present. Instead, our method effectively goes through all possible combinations of SVs. Since ODM works on length scales typically not reachable with other techniques, our methodology is a promising tool for identifying arbitrary combinations of genomic alterations.
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Affiliation(s)
- Albertas Dvirnas
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Callum Stewart
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Vilhelm Müller
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Santosh Kumar Bikkarolla
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Karolin Frykholm
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Linus Sandegren
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Erik Kristiansson
- Department of Mathematical Sciences, Chalmers University of Technology and the University of Gothenburg, Gothenburg, Sweden
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Tobias Ambjörnsson
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
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11
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Bucci G, Gadelrab K, Spakowitz AJ. Free Energy and Dynamics of Annihilation of Topological Defects in Nanoconfined DNA. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giovanna Bucci
- Robert Bosch LLC, 384 Santa Trinita Ave, Sunnyvale, California 94085, United States
| | - Karim Gadelrab
- Robert Bosch LLC, 1 Kendall Square, Suite 7-101, Cambridge, Massachusetts 02139, United States
| | - Andrew J. Spakowitz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- Biophysics Program, Stanford University, Stanford, California 94305, United States
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12
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Morrin GT, Kienle DF, Schwartz DK. Diffusion of Short Semiflexible DNA Polymer Chains in Strong and Moderate Confinement. ACS Macro Lett 2021; 10:1191-1195. [PMID: 35549041 DOI: 10.1021/acsmacrolett.1c00470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In many technological applications, DNA is confined within nanoenvironments that are smaller than the size of the unconfined polymer in solution. However, the dependence of the diffusion coefficient on molecular weight and characteristic confinement dimension remains poorly understood in this regime. Here, convex lens-induced confinement (CLiC) was leveraged to examine how the diffusion of short DNA fragments varied as a function of slit height by using single-molecule fluorescence tracking microscopy. The diffusion coefficient followed approximate power law behavior versus confinement height, with exponents of 0.27 ± 0.01, 0.32 ± 0.02, and 0.42 ± 0.06 for 692, 1343, and 2686 base pair chains, respectively. The weak dependence on slit height suggests that shorter semiflexible chains may adopt increasingly rodlike conformations and therefore experience weaker excluded-volume interactions as the confinement dimension is reduced. The diffusion coefficient versus molecular weight also exhibited apparent power law behavior, with exponents that varied slightly (from -0.89 to -0.85) with slit height, consistent with hydrodynamic interactions intermediate between Rouse and Zimm model predictions.
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Affiliation(s)
- Gregory T Morrin
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel F Kienle
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
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KK S, Lin YL, Sewunet T, Wrande M, Sandegren L, Giske CG, Westerlund F. A Parallelized Nanofluidic Device for High-Throughput Optical DNA Mapping of Bacterial Plasmids. MICROMACHINES 2021; 12:1234. [PMID: 34683285 PMCID: PMC8538381 DOI: 10.3390/mi12101234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 12/03/2022]
Abstract
Optical DNA mapping (ODM) has developed into an important technique for DNA analysis, where single DNA molecules are sequence-specifically labeled and stretched, for example, in nanofluidic channels. We have developed an ODM assay to analyze bacterial plasmids-circular extrachromosomal DNA that often carry genes that make bacteria resistant to antibiotics. As for most techniques, the next important step is to increase throughput and automation. In this work, we designed and fabricated a nanofluidic device that, together with a simple automation routine, allows parallel analysis of up to 10 samples at the same time. Using plasmids encoding extended-spectrum beta-lactamases (ESBL), isolated from Escherichiacoli and Klebsiellapneumoniae, we demonstrate the multiplexing capabilities of the device when it comes to both many samples in parallel and different resistance genes. As a final example, we combined the device with a novel protocol for rapid cultivation and extraction of plasmids from fecal samples collected from patients. This combined protocol will make it possible to analyze many patient samples in one device already on the day the sample is collected, which is an important step forward for the ODM analysis of plasmids in clinical diagnostics.
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Affiliation(s)
- Sriram KK
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.)
| | - Yii-Lih Lin
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.)
| | - Tsegaye Sewunet
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, 141 52 Stockholm, Sweden; (T.S.); (C.G.G.)
| | - Marie Wrande
- Department of Medical Biochemistry and Microbiology, Uppsala University, 752 37 Uppsala, Sweden; (M.W.); (L.S.)
| | - Linus Sandegren
- Department of Medical Biochemistry and Microbiology, Uppsala University, 752 37 Uppsala, Sweden; (M.W.); (L.S.)
| | - Christian G. Giske
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, 141 52 Stockholm, Sweden; (T.S.); (C.G.G.)
- Clinical Microbiology, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.)
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14
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Lin YL, Sewunet T, KK S, Giske CG, Westerlund F. Optical maps of plasmids as a proxy for clonal spread of MDR bacteria: a case study of an outbreak in a rural Ethiopian hospital. J Antimicrob Chemother 2021; 75:2804-2811. [PMID: 32653928 PMCID: PMC7678893 DOI: 10.1093/jac/dkaa258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/24/2020] [Accepted: 05/14/2020] [Indexed: 01/09/2023] Open
Abstract
Objectives MDR bacteria have become a prevailing health threat worldwide. We here aimed to use optical DNA mapping (ODM) as a rapid method to trace nosocomial spread of bacterial clones and gene elements. We believe that this method has the potential to be a tool of pivotal importance for MDR control. Methods Twenty-four Escherichia coli samples of ST410 from three different wards were collected at an Ethiopian hospital and their plasmids were analysed by ODM. Plasmids were specifically digested with Cas9 targeting the antibiotic resistance genes, stained by competitive binding and confined in nanochannels for imaging. The resulting intensity profiles (barcodes) for each plasmid were compared to identify potential clonal spread of resistant bacteria. Results ODM demonstrated that a large fraction of the patients carried bacteria with a plasmid of the same origin, carrying the ESBL gene blaCTX-M-15, suggesting clonal spread. The results correlate perfectly with core genome (cg)MLST data, where bacteria with the same plasmid also had very similar cgMLST profiles. Conclusions ODM is a rapid discriminatory method for identifying plasmids and antibiotic resistance genes. Long-range deletions/insertions, which are challenging for short-read next-generation sequencing, can be easily identified and used to trace bacterial clonal spread. We propose that plasmid typing can be a useful tool to identify clonal spread of MDR bacteria. Furthermore, the simplicity of the method enables possible future application in low- and middle-income countries.
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Affiliation(s)
- Yii-Lih Lin
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Tsegaye Sewunet
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- School of Laboratory Sciences, Department of Microbiology, Jimma University, Jimma, Ethiopia
| | - Sriram KK
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Christian G Giske
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Corresponding author. E-mail:
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15
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Jiang K, Humbert N, K K S, Rouzina I, Mely Y, Westerlund F. The HIV-1 nucleocapsid chaperone protein forms locally compacted globules on long double-stranded DNA. Nucleic Acids Res 2021; 49:4550-4563. [PMID: 33872352 PMCID: PMC8096146 DOI: 10.1093/nar/gkab236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 01/14/2023] Open
Abstract
The nucleocapsid (NC) protein plays key roles in Human Immunodeficiency Virus 1 (HIV-1) replication, notably by condensing and protecting the viral RNA genome and by chaperoning its reverse transcription into double-stranded DNA (dsDNA). Recent findings suggest that integration of viral dsDNA into the host genome, and hence productive infection, is linked to a small subpopulation of viral complexes where reverse transcription was completed within the intact capsid. Therefore, the synthesized dsDNA has to be tightly compacted, most likely by NC, to prevent breaking of the capsid in these complexes. To investigate NC’s ability to compact viral dsDNA, we here characterize the compaction of single dsDNA molecules under unsaturated NC binding conditions using nanofluidic channels. Compaction is shown to result from accumulation of NC at one or few compaction sites, which leads to small dsDNA condensates. NC preferentially initiates compaction at flexible regions along the dsDNA, such as AT-rich regions and DNA ends. Upon further NC binding, these condensates develop into a globular state containing the whole dsDNA molecule. These findings support NC’s role in viral dsDNA compaction within the mature HIV-1 capsid and suggest a possible scenario for the gradual dsDNA decondensation upon capsid uncoating and NC loss.
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Affiliation(s)
- Kai Jiang
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Sriram K K
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
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Kwon S, Lee H, Kim SJ. Pulsed electric field-assisted overlimiting current enhancement through a perm-selective membrane. LAB ON A CHIP 2021; 21:2153-2162. [PMID: 33908534 DOI: 10.1039/d1lc00064k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Overlimiting current through a perm-selective membrane has been actively researched not only for the fundamental advancement of electrokinetics but also for energy/environmental applications such as electrodialysis, fuel cells, etc. In particular, various strategies were reported for the enhancement of overlimiting current because these applications demand efficient mass transport through the membrane. In this work, we presented in operando visualization and rigorous numerical study for the overlimiting current density enhancement using a pulsed electric field which is one of the most cost-effective parameters to be externally controlled. We clearly demonstrated that the current density had a peak value as a function of the pulse frequency and would suggest its correlation to a concentration profile and diffusion relaxation time ([small tau, Greek, tilde]diff). As the pulse frequency was chosen which is similar to ([small tau, Greek, tilde]diff)-1, the concentration profiles (i.e. established current paths) were maintained even in off-state due to remnant current paths helping the fast ion transportation. The fundamental evidence presented in this work would provide a strategical design of a perm-selective membrane system for a higher mass transportation efficiency.
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Affiliation(s)
- Soonhyun Kwon
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
| | - Hyomin Lee
- Department of Chemical and Biological engineering, Jeju National University, 63243, Republic of Korea.
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Republic of Korea. and Inter-university Semiconductor Research Center, Seoul National University, Seoul, 08826, South Korea and Nano Systems Institute, Seoul National University, Seoul, 08826, South Korea
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17
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Karami N, KK S, Yazdanshenas S, Lin YL, Jaén-Luchoro D, Ekedahl E, Parameshwaran S, Lindblom A, Åhrén C, Westerlund F. Identity of blaCTX-M Carrying Plasmids in Sequential ESBL- E. coli Isolates from Patients with Recurrent Urinary Tract Infections. Microorganisms 2021; 9:microorganisms9061138. [PMID: 34070515 PMCID: PMC8226486 DOI: 10.3390/microorganisms9061138] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/10/2021] [Accepted: 05/20/2021] [Indexed: 11/16/2022] Open
Abstract
Plasmid-mediated multidrug resistance in E. coli is becoming increasingly prevalent. Considering this global threat to human health, it is important to understand how plasmid-mediated resistance spreads. From a cohort of 123 patients with recurrent urinary tract infections (RUTI) due to extended spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli), only five events with a change of ESBL E. coli strain between RUTI episodes were identified. Their blaCTX-M encoding plasmids were compared within each pair of isolates using optical DNA mapping (ODM) and PCR-based replicon typing. Despite similar blaCTX-M genes and replicon types, ODM detected only one case with identical plasmids in the sequential ESBL E. coli strains, indicating that plasmid transfer could have occurred. For comparison, plasmids from seven patients with the same ESBL E. coli strain reoccurring in both episodes were analyzed. These plasmids (encoding blaCTX-M-3, blaCTX-M-14, and blaCTX-M-15) were unaltered for up to six months between recurrent infections. Thus, transmission of blaCTX-M plasmids appears to be a rare event during the course of RUTI. Despite the limited number (n = 23) of plasmids investigated, similar blaCTX-M-15 plasmids in unrelated isolates from different patients were detected, suggesting that some successful plasmids could be associated with specific strains, or are more easily transmitted.
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Affiliation(s)
- Nahid Karami
- Institute of Biomedicine, Department of Infectious Diseases and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Guldhedsgatan 10 A, 413 46 Gothenburg, Sweden; (S.Y.); (D.J.-L.); (A.L.); (C.Å.)
- Västra Götaland Region, Sahlgrenska University Hospital, Department of Clinical Microbiology, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden
- Correspondence: (N.K.); (F.W.); Tel.: +46-31-342-6173 (N.K.); +46-31-772-3049 (F.W.)
| | - Sriram KK
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.); (E.E.); (S.P.)
| | - Shora Yazdanshenas
- Institute of Biomedicine, Department of Infectious Diseases and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Guldhedsgatan 10 A, 413 46 Gothenburg, Sweden; (S.Y.); (D.J.-L.); (A.L.); (C.Å.)
- Västra Götaland Region, Sahlgrenska University Hospital, Department of Clinical Microbiology, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden
| | - Yii-Lih Lin
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.); (E.E.); (S.P.)
| | - Daniel Jaén-Luchoro
- Institute of Biomedicine, Department of Infectious Diseases and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Guldhedsgatan 10 A, 413 46 Gothenburg, Sweden; (S.Y.); (D.J.-L.); (A.L.); (C.Å.)
| | - Elina Ekedahl
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.); (E.E.); (S.P.)
| | - Sanjana Parameshwaran
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.); (E.E.); (S.P.)
| | - Anna Lindblom
- Institute of Biomedicine, Department of Infectious Diseases and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Guldhedsgatan 10 A, 413 46 Gothenburg, Sweden; (S.Y.); (D.J.-L.); (A.L.); (C.Å.)
- Västra Götaland Region, Sahlgrenska University Hospital, Department of Clinical Microbiology, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden
| | - Christina Åhrén
- Institute of Biomedicine, Department of Infectious Diseases and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Guldhedsgatan 10 A, 413 46 Gothenburg, Sweden; (S.Y.); (D.J.-L.); (A.L.); (C.Å.)
- Swedish Strategic Program against Antimicrobial Resistance (Strama), Västra Götaland Region, Regionens Hus, 405 44 Gothenburg, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 412 96 Gothenburg, Sweden; (S.K.); (Y.-L.L.); (E.E.); (S.P.)
- Correspondence: (N.K.); (F.W.); Tel.: +46-31-342-6173 (N.K.); +46-31-772-3049 (F.W.)
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18
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Ma Z, Dorfman KD. Diffusion of Knotted DNA Molecules in Nanochannels in the Extended de Gennes Regime. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zixue Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota−Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota−Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States
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19
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Yang W, Radha B, Choudhary A, You Y, Mettela G, Geim A, Aksimentiev A, Keerthi A, Dekker C. Translocation of DNA through Ultrathin Nanoslits. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007682. [PMID: 33522015 PMCID: PMC8011289 DOI: 10.1002/adma.202007682] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Indexed: 05/29/2023]
Abstract
2D nanoslit devices, where two crystals with atomically flat surfaces are separated by only a few nanometers, have attracted considerable attention because their tunable control over the confinement allows for the discovery of unusual transport behavior of gas, water, and ions. Here, the passage of double-stranded DNA molecules is studied through nanoslits fabricated from exfoliated 2D materials, such as graphene or hexagonal boron nitride, and the DNA polymer behavior is examined in this tight confinement. Two types of events are observed in the ionic current: long current blockades that signal DNA translocation and short spikes where DNA enters the slits but withdraws. DNA translocation events exhibit three distinct phases in their current-blockade traces-loading, translation, and exit. Coarse-grained molecular dynamics simulation allows the different polymer configurations of these phases to be identified. DNA molecules, including folds and knots in their polymer structure, are observed to slide through the slits with near-uniform velocity without noticeable frictional interactions of DNA with the confining graphene surfaces. It is anticipated that this new class of 2D-nanoslit devices will provide unique ways to study polymer physics and enable lab-on-a-chip biotechnology.
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Affiliation(s)
- Wayne Yang
- Kavli Institute of Nanoscience Delft, Delft University of Technology, The Netherlands
| | - Boya Radha
- Department of Physics & Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - Adnan Choudhary
- Department of Physics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yi You
- Department of Physics & Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - Gangaiah Mettela
- Department of Physics & Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Andre Geim
- Department of Physics & Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - Aleksei Aksimentiev
- Department of Physics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ashok Keerthi
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- Department of Chemistry, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Cees Dekker
- Kavli Institute of Nanoscience Delft, Delft University of Technology, The Netherlands
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20
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Bhattacharjee G, Gohil N, Lam NL, Singh V. CRISPR-based diagnostics for detection of pathogens. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 181:45-57. [PMID: 34127201 DOI: 10.1016/bs.pmbts.2021.01.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The improved sensitivity and superior specificity associated with the use of molecular assays has improved the fate of disease diagnosis by bestowing the clinicians with outcomes that are both rapid and precise. In recent years, CRISPR has made considerable progress in in vitro diagnostic platform which has paved its way for developing rapid and sensitive CRISPR-based diagnostic tools. Improved perception and better understanding of diverse CRISPR-Cas systems has broadened the reach of CRISPR applications for not just early detection of pathogens but also for early onset of diseases such as cancer. The inherent allele specificity of CRISPR is the predominant reason for its application in designing a diagnostic-tool that is field-deployable, portable, sensitive, specific and rapid. In this chapter, we highlight various CRISPR-based diagnostic platforms, its applications, challenges and future prospects of the CRISPR-Cas system.
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Affiliation(s)
- Gargi Bhattacharjee
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
| | - Nisarg Gohil
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
| | - Navya Lavina Lam
- The J. David Gladstone Institutes, San Francisco, CA, United States
| | - Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India.
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21
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Hejazi S, Pahlavanzadeh H, Elliott JAW. Thermodynamic Investigation of the Effect of Electric Field on Solid-Liquid Equilibrium. J Phys Chem B 2021; 125:1271-1281. [PMID: 33497220 DOI: 10.1021/acs.jpcb.0c08754] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, the thermal, mechanical, and chemical equilibrium conditions are derived for binary solid-liquid equilibrium under the effect of an electric field. As an example, the effect of an electric field on the water/glycerol solid-liquid phase diagram is computed over the complete mole fraction range. We show that the application of an electric field can affect the composition dependent freezing and precipitating processes, changing freezing and precipitating temperatures and changing the eutectic point temperature and mole fraction.
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Affiliation(s)
- Sima Hejazi
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta Canada T6G 1H9.,Faculty of Chemical Engineering, Tarbiat Modares University, Tehran 14115-336, Iran
| | - Hassan Pahlavanzadeh
- Faculty of Chemical Engineering, Tarbiat Modares University, Tehran 14115-336, Iran
| | - Janet A W Elliott
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta Canada T6G 1H9
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22
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Ohshiro T, Komoto Y, Taniguchi M. Single-Molecule Counting of Nucleotide by Electrophoresis with Nanochannel-Integrated Nano-Gap Devices. MICROMACHINES 2020; 11:mi11110982. [PMID: 33142705 PMCID: PMC7693128 DOI: 10.3390/mi11110982] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/28/2020] [Accepted: 10/28/2020] [Indexed: 12/11/2022]
Abstract
We utilized electrophoresis to control the fluidity of sample biomolecules in sample aqueous solutions inside the nanochannel for single-molecule detection by using a nanochannel-integrated nanogap electrode, which is composed of a nano-gap sensing electrode, nanochannel, and tapered focusing channel. In order to suppress electro-osmotic flow and thermal convection inside this nanochannel, we optimized the reduction ratios of the tapered focusing channel, and the ratio of inlet 10 μm to outlet 0.5 μm was found to be high performance of electrophoresis with lower concentration of 0.05 × TBE (Tris/Borate/EDTA) buffer containing a surfactant of 0.1 w/v% polyvinylpyrrolidone (PVP). Under the optimized conditions, single-molecule electrical measurement of deoxyguanosine monophosphate (dGMP) was performed and it was found that the throughput was significantly improved by nearly an order of magnitude compared to that without electrophoresis. In addition, it was also found that the long-duration signals that could interfere with discrimination were significantly reduced. This is because the strong electrophoresis flow inside the nanochannels prevents the molecules’ adsorption near the electrodes. This single-molecule electrical measurement with nanochannel-integrated nano-gap electrodes by electrophoresis significantly improved the throughput of signal detection and identification accuracy.
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Real-time compaction of nanoconfined DNA by an intrinsically disordered macromolecular counterion. Biochem Biophys Res Commun 2020; 533:175-180. [PMID: 32951838 DOI: 10.1016/j.bbrc.2020.06.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/10/2020] [Indexed: 12/31/2022]
Abstract
We demonstrate how a recently developed nanofluidic device can be used to study protein-induced compaction of genome-length DNA freely suspended in solution. The protein we use in this study is the hepatitis C virus core protein (HCVcp), which is a positively charged, intrinsically disordered protein. Using nanofluidic devices in combination with fluorescence microscopy, we observe that protein-induced compaction preferentially begins at the ends of linear DNA. This observation would be difficult to make with many other single-molecule techniques, which generally require the DNA ends to be anchored to a substrate. We also demonstrate that this protein-induced compaction is reversible and can be dynamically modulated by exposing the confined DNA molecules to solutions containing either HCVcp (to promote compaction) or Proteinase K (to disassemble the compact nucleo-protein complex). Although the natural binding partner for HCVcp is genomic viral RNA, the general biophysical principles governing protein-induced compaction of DNA are likely relevant for a broad range of nucleic acid-binding proteins and their targets.
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Ghosh S, Karedla N, Gregor I. Single-molecule confinement with uniform electrodynamic nanofluidics. LAB ON A CHIP 2020; 20:3249-3257. [PMID: 32760965 DOI: 10.1039/d0lc00398k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To date, we could not engineer Nature's ability to dynamically handle diffusing single molecules in the liquid-phase as it takes place in pore-forming proteins and tunnelling nanotubes. Consistent handling of individual single molecules in a liquid is of paramount importance to fundamental molecular studies and technological benefits, like single-molecule level separation and sorting for early biomedical diagnostics, microscopic studies of molecular interactions and electron/optical microscopy of molecules and nanomaterials. We can consistently resolve the dynamics of diffusing single molecules if they are confined within a uniform dielectric environment at nanometre length-scales. A uniform dielectric environment is the key characteristic since intrinsic electronic properties of molecules were modified while interacting with any surfaces, and the effect is not the same from one dielectric surface to another. We present dynamic nanofluidic detection of optically active single molecules in a liquid. An all-silica nanofluidic environment was used to electrokinetically handle individual single-molecules where molecular shot noise was resolved. We recorded the single-molecule motion of small fragments of DNA, carbon-nanodots, and organic fluorophores in water. The electrokinetic 1D molecular mass transport under two-focus fluorescence correlation spectroscopy (2fFCS) showed confinement-induced modified molecular interactions (due to various inter-molecular repulsive and attractive forces), which have been theoretically interpreted as molecular shot noise. Our demonstration of high-throughput nanochannel fabrication, 2fFCS-based 1D confined detection of fast-moving single molecules and fundamental understanding of molecular shot noise may open an avenue for single-molecule experiments where physical manipulation of dynamics is necessary.
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Affiliation(s)
- Siddharth Ghosh
- III. Institute of Physics - Biophysics and Complex Systems, University of Göttingen, Göttingen, Germany.
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25
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Abstract
The DNA of our cells is constantly exposed to various types of damaging agents. One of the most critical types of damage is when both strands of the DNA break, and thus such breaks need to be efficiently repaired. It is known that CtIP promotes nucleases in DNA break repair. Here we show that CtIP can also hold the two DNA strands together in solution when DNA is free to move, using novel methodology that allows the monitoring of thousands of single DNA molecules in nanofabricated devices. DNA bridging likely facilitates the enzymatic repair steps and identifies novel CtIP functions that are crucial for repairing broken DNA. The early steps of DNA double-strand break (DSB) repair in human cells involve the MRE11-RAD50-NBS1 (MRN) complex and its cofactor, phosphorylated CtIP. The roles of these proteins in nucleolytic DSB resection are well characterized, but their role in bridging the DNA ends for efficient and correct repair is much less explored. Here we study the binding of phosphorylated CtIP, which promotes the endonuclease activity of MRN, to single long (∼50 kb) DNA molecules using nanofluidic channels and compare it to the yeast homolog Sae2. CtIP bridges DNA in a manner that depends on the oligomeric state of the protein, and truncated mutants demonstrate that the bridging depends on CtIP regions distinct from those that stimulate the nuclease activity of MRN. Sae2 is a much smaller protein than CtIP, and its bridging is significantly less efficient. Our results demonstrate that the nuclease cofactor and structural functions of CtIP may depend on the same protein population, which may be crucial for CtIP functions in both homologous recombination and microhomology-mediated end-joining.
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26
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Bucci G, Spakowitz AJ. Systematic Approach toward Accurate and Efficient DNA Sequencing via Nanoconfinement. ACS Macro Lett 2020; 9:1184-1191. [PMID: 35653210 DOI: 10.1021/acsmacrolett.0c00423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Coarse-grained modeling tools are employed to simulate the mechanics of DNA loading within a nanoscale confinement and predict semiflexible polymer conformations within the confinement, providing design recommendations for DNA-sequencing devices. A workflow is developed to quantify competing requirements of efficiency and accuracy and extract metrics that guide design optimization. The mean first-passage time for DNA loading is calculated as a function of the nanochannel geometry and the applied electric field. We analyze the interplay between the free energy of confinement and the electric potential energy in achieving high-throughput, base-pair detection. The single-read probability is investigated as informative metrics for sequencing accuracy and for sensing-strategy design. High cost, low throughput, and low accuracy have so far limited the adoption of nanochannel analysis and other long-read technologies. Our work directly addresses these limitations with a systematic approach that is scalable to long molecules and complex geometries.
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Affiliation(s)
- Giovanna Bucci
- Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
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27
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Affiliation(s)
- Zixue Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
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28
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Jonchhe S, Pandey S, Karna D, Pokhrel P, Cui Y, Mishra S, Sugiyama H, Endo M, Mao H. Duplex DNA Is Weakened in Nanoconfinement. J Am Chem Soc 2020; 142:10042-10049. [PMID: 32383870 PMCID: PMC7295077 DOI: 10.1021/jacs.0c01978] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
For proteins and DNA secondary structures such as G-quadruplexes and i-motifs, nanoconfinement can facilitate their folding and increase structural stabilities. However, the properties of the physiologically prevalent B-DNA duplex have not been elucidated inside the nanocavity. Using a 17-bp DNA duplex in the form of a hairpin stem, here, we probed folding and unfolding transitions of the hairpin DNA duplex inside a DNA origami nanocavity. Compared to the free solution, the DNA hairpin inside the nanocage with a 15 × 15 nm cross section showed a drastic decrease in mechanical (20 → 9 pN) and thermodynamic (25 → 6 kcal/mol) stabilities. Free energy profiles revealed that the activation energy of unzipping the hairpin DNA duplex decreased dramatically (28 → 8 kcal/mol), whereas the transition state moved closer to the unfolded state inside the nanocage. All of these indicate that nanoconfinement weakens the stability of the hairpin DNA duplex to an unexpected extent. In a DNA hairpin made of a stem that contains complementary telomeric G-quadruplex (GQ) and i-motif (iM) forming sequences, formation of the Hoogsteen base pairs underlining the GQ or iM is preferred over the Watson-Crick base pairs in the DNA hairpin. These results shed light on the behavior of DNA in nanochannels, nanopores, or nanopockets of various natural or synthetic machineries. It also elucidates an alternative pathway to populate noncanonical DNA over B-DNA in the cellular environment where the nanocavity is abundant.
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Affiliation(s)
- Sagun Jonchhe
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Shankar Pandey
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Deepak Karna
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Pravin Pokhrel
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Yunxi Cui
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Shubham Mishra
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
- Institute for Integrated Cell–Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
- Institute for Integrated Cell–Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Masayuki Endo
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
- Institute for Integrated Cell–Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Hanbin Mao
- Department of Chemistry & Biochemistry, Kent State University, Kent, OH 44242, USA
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29
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Müller V, Nyblom M, Johnning A, Wrande M, Dvirnas A, KK S, Giske CG, Ambjörnsson T, Sandegren L, Kristiansson E, Westerlund F. Cultivation-Free Typing of Bacteria Using Optical DNA Mapping. ACS Infect Dis 2020; 6:1076-1084. [PMID: 32294378 PMCID: PMC7304876 DOI: 10.1021/acsinfecdis.9b00464] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Indexed: 01/06/2023]
Abstract
A variety of pathogenic bacteria can infect humans, and rapid species identification is crucial for the correct treatment. However, the identification process can often be time-consuming and depend on the cultivation of the bacterial pathogen(s). Here, we present a stand-alone, enzyme-free, optical DNA mapping assay capable of species identification by matching the intensity profiles of large DNA molecules to a database of fully assembled bacterial genomes (>10 000). The assay includes a new data analysis strategy as well as a general DNA extraction protocol for both Gram-negative and Gram-positive bacteria. We demonstrate that the assay is capable of identifying bacteria directly from uncultured clinical urine samples, as well as in mixtures, with the potential to be discriminative even at the subspecies level. We foresee that the assay has applications both within research laboratories and in clinical settings, where the time-consuming step of cultivation can be minimized or even completely avoided.
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Affiliation(s)
- Vilhelm Müller
- Department of Biology
and Biological Engineering, Chalmers University
of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - My Nyblom
- Department of Biology
and Biological Engineering, Chalmers University
of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Anna Johnning
- Department of Mathematical
Sciences, Chalmers University of Technology
and the University of Gothenburg, 412 96 Gothenburg, Sweden
- Systems and Data Analysis, Fraunhofer-Chalmers
Centre, Chalmers Science
Park, 412 88 Gothenburg, Sweden
- Centre for Antibiotic Resistance Research,
CARe, University of Gothenburg, Box 440, 405 30 Gothenburg, Sweden
| | - Marie Wrande
- Department of Medical
Biochemistry and Microbiology, Uppsala University, Husargatan 3, Box
582, 751 23 Uppsala, Sweden
| | - Albertas Dvirnas
- Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, 223 62 Lund, Sweden
| | - Sriram KK
- Department of Biology
and Biological Engineering, Chalmers University
of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Christian G. Giske
- Department of Laboratory Medicine, Karolinska
Institutet, Alfred Nobels
Allé 8, 141 86 Stockholm, Sweden
- Department of Clinical
Microbiology, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Tobias Ambjörnsson
- Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, 223 62 Lund, Sweden
| | - Linus Sandegren
- Department of Medical
Biochemistry and Microbiology, Uppsala University, Husargatan 3, Box
582, 751 23 Uppsala, Sweden
| | - Erik Kristiansson
- Department of Mathematical
Sciences, Chalmers University of Technology
and the University of Gothenburg, 412 96 Gothenburg, Sweden
- Centre for Antibiotic Resistance Research,
CARe, University of Gothenburg, Box 440, 405 30 Gothenburg, Sweden
| | - Fredrik Westerlund
- Department of Biology
and Biological Engineering, Chalmers University
of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
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30
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Li M, Wang J. Stretching Wormlike Chains in Narrow Tubes of Arbitrary Cross-Sections. Polymers (Basel) 2019; 11:E2050. [PMID: 31835594 PMCID: PMC6960511 DOI: 10.3390/polym11122050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 12/06/2019] [Indexed: 12/03/2022] Open
Abstract
We considered the stretching of semiflexible polymer chains confined in narrow tubes with arbitrary cross-sections. Based on the wormlike chain model and technique of normal mode decomposition in statistical physics, we derived a compact analytical expression on the force-confinement-extension relation of the chains. This single formula was generalized to be valid for tube confinements with arbitrary cross-sections. In addition, we extended the generalized bead-rod model for Brownian dynamics simulations of confined polymer chains subjected to force stretching, so that the confinement effects to the chains applied by the tubes with arbitrary cross-sections can be quantitatively taken into account through numerical simulations. Extensive simulation examples on the wormlike chains confined in tubes of various shapes quantitatively justified the theoretically derived generalized formula on the force-confinement-extension relation of the chains.
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Affiliation(s)
| | - Jizeng Wang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China;
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31
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Müller V, Dvirnas A, Andersson J, Singh V, Kk S, Johansson P, Ebenstein Y, Ambjörnsson T, Westerlund F. Enzyme-free optical DNA mapping of the human genome using competitive binding. Nucleic Acids Res 2019; 47:e89. [PMID: 31165870 PMCID: PMC6735870 DOI: 10.1093/nar/gkz489] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/03/2019] [Accepted: 05/22/2019] [Indexed: 01/24/2023] Open
Abstract
Optical DNA mapping (ODM) allows visualization of long-range sequence information along single DNA molecules. The data can for example be used for detecting long range structural variations, for aiding DNA sequence assembly of complex genomes and for mapping epigenetic marks and DNA damage across the genome. ODM traditionally utilizes sequence specific marks based on nicking enzymes, combined with a DNA stain, YOYO-1, for detection of the DNA contour. Here we use a competitive binding approach, based on YOYO-1 and netropsin, which highlights the contour of the DNA molecules, while simultaneously creating a continuous sequence specific pattern, based on the AT/GC variation along the detected molecule. We demonstrate and validate competitive-binding-based ODM using bacterial artificial chromosomes (BACs) derived from the human genome and then turn to DNA extracted from white blood cells. We generalize our findings with in-silico simulations that show that we can map a vast majority of the human genome. Finally, we demonstrate the possibility of combining competitive binding with enzymatic labeling by mapping DNA damage sites induced by the cytotoxic drug etoposide to the human genome. Overall, we demonstrate that competitive-binding-based ODM has the potential to be used both as a standalone assay for studies of the human genome, as well as in combination with enzymatic approaches, some of which are already commercialized.
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Affiliation(s)
- Vilhelm Müller
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Albertas Dvirnas
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - John Andersson
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Vandana Singh
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Sriram Kk
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Pegah Johansson
- Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Yuval Ebenstein
- School of Chemistry, Center for Nanoscience and Nanotechnology, Center for Light-Matter Interaction, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tobias Ambjörnsson
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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32
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Hydrophobic catalysis and a potential biological role of DNA unstacking induced by environment effects. Proc Natl Acad Sci U S A 2019; 116:17169-17174. [PMID: 31413203 PMCID: PMC6717297 DOI: 10.1073/pnas.1909122116] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The main stabilizer of the DNA double helix is not the base-pair hydrogen bonds but coin-pile stacking of base pairs, whose hydrophobic cohesion, requiring abundant water, indirectly makes the DNA interior dry so that hydrogen bonds can exert full recognition power. We report that certain semihydrophobic agents depress the stacking energy (measurable in single-molecule experiments), leading to transiently occurring holes in the base-pair stack (monitorable via binding of threading intercalators). Similar structures observed in DNA complexes with RecA and Rad51, and previous observations of spontaneous strand exchange catalyzed in semihydrophobic model systems, make us propose that some hydrophobic protein residues may have roles in catalyzing homologous recombination. We speculate that hydrophobic catalysis is a general phenomenon in DNA enzymes. Hydrophobic base stacking is a major contributor to DNA double-helix stability. We report the discovery of specific unstacking effects in certain semihydrophobic environments. Water-miscible ethylene glycol ethers are found to modify structure, dynamics, and reactivity of DNA by mechanisms possibly related to a biologically relevant hydrophobic catalysis. Spectroscopic data and optical tweezers experiments show that base-stacking energies are reduced while base-pair hydrogen bonds are strengthened. We propose that a modulated chemical potential of water can promote “longitudinal breathing” and the formation of unstacked holes while base unpairing is suppressed. Flow linear dichroism in 20% diglyme indicates a 20 to 30% decrease in persistence length of DNA, supported by an increased flexibility in single-molecule nanochannel experiments in poly(ethylene glycol). A limited (3 to 6%) hyperchromicity but unaffected circular dichroism is consistent with transient unstacking events while maintaining an overall average B-DNA conformation. Further information about unstacking dynamics is obtained from the binding kinetics of large thread-intercalating ruthenium complexes, indicating that the hydrophobic effect provides a 10 to 100 times increased DNA unstacking frequency and an “open hole” population on the order of 10−2 compared to 10−4 in normal aqueous solution. Spontaneous DNA strand exchange catalyzed by poly(ethylene glycol) makes us propose that hydrophobic residues in the L2 loop of recombination enzymes RecA and Rad51 may assist gene recombination via modulation of water activity near the DNA helix by hydrophobic interactions, in the manner described here. We speculate that such hydrophobic interactions may have catalytic roles also in other biological contexts, such as in polymerases.
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33
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Esmek FM, Bayat P, Pérez-Willard F, Volkenandt T, Blick RH, Fernandez-Cuesta I. Sculpturing wafer-scale nanofluidic devices for DNA single molecule analysis. NANOSCALE 2019; 11:13620-13631. [PMID: 31290915 DOI: 10.1039/c9nr02979f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present micro- and nanofluidic devices with 3D structures and nanochannels with multiple depths for the analysis of single molecules of DNA. Interfacing the nanochannels with graded and 3D inlets allows the improvement of the flow and controls not only the translocation speed of the DNA but also its conformation inside the nanochannels. The complex, multilevel, multiscale fluidic circuits are patterned in a simple, two-minute imprinting step. The stamp, the key of the technology, is directly milled by focused ion beam, which allows patterning nanochannels with different cross sections and depths, together with 3D transient inlets, all at once. Having such a variety of structures integrated in the same sample allows studying, optimizing and directly comparing their effect on the DNA flow. Here, DNA translocation is studied in long (160 µm) and short (5-40 µm) nanochannels. We study the homogeneity of the stretched molecules in long, meander nanochannels made with this technology. In addition, we analyze the effect of the different types of inlet structures interfacing short nanochannels. We observe pre-stretching and an optimal flow, and no hairpin formation, when the inlets have gradually decreasing widths and depths. In contrast, when the nanochannels are faced with an abrupt transition, we observe clogging and hairpin formation. In addition, 3D inlets strongly decrease the DNA molecules' speed before they enter the nanochannels, and help capturing more DNA molecules. The robustness and versatility of this technology and DNA testing results evidence the potential of imprinted devices in biomedical applications as low cost, disposable lab-on-a-chip devices.
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Affiliation(s)
- Franziska M Esmek
- Institut für Nanostruktur- und Festkörperphysik (INF)/Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Parisa Bayat
- Institut für Nanostruktur- und Festkörperphysik (INF)/Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | | | - Tobias Volkenandt
- Carl Zeiss Microscopy GmbH, Carl-Zeiss-Str. 22, 73447 Oberkochen, Germany
| | - Robert H Blick
- Institut für Nanostruktur- und Festkörperphysik (INF)/Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Irene Fernandez-Cuesta
- Institut für Nanostruktur- und Festkörperphysik (INF)/Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
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34
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Optical DNA Mapping Combined with Cas9-Targeted Resistance Gene Identification for Rapid Tracking of Resistance Plasmids in a Neonatal Intensive Care Unit Outbreak. mBio 2019; 10:mBio.00347-19. [PMID: 31289171 PMCID: PMC6747713 DOI: 10.1128/mbio.00347-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
This study presents how a novel method, based on visualizing single plasmids using sequence-specific fluorescent labeling, could be used to analyze the genetic dynamics of an outbreak of resistant bacteria in a neonatal intensive care unit at a Swedish hospital. Plasmids are a central reason for the rapid global spread of bacterial resistance to antibiotics. In a single experimental procedure, this method replaces many traditional plasmid analysis techniques that together provide limited details and are slow to perform. The method is much faster than long-read whole-genome sequencing and offers direct genetic comparison of patient samples. We could conclude that no transfer of resistance plasmids had occurred between different bacteria during the outbreak and that secondary cases of ESBL-producing Enterobacteriaceae carriage were instead likely due to influx of new strains. We believe that the method offers potential in improving surveillance and infection control of resistant bacteria in hospitals. The global spread of antibiotic resistance among Enterobacteriaceae is largely due to multidrug resistance plasmids that can transfer between different bacterial strains and species. Horizontal gene transfer of resistance plasmids can complicate hospital outbreaks and cause problems in epidemiological tracing, since tracing is usually based on bacterial clonality. We have developed a method, based on optical DNA mapping combined with Cas9-assisted identification of resistance genes, which is used here to characterize plasmids during an extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae outbreak at a Swedish neonatal intensive care unit. The outbreak included 17 neonates initially colonized with ESBL-producing Klebsiella pneumoniae (ESBL-KP), some of which were found to carry additional ESBL-producing Escherichia coli (ESBL-EC) in follow-up samples. We demonstrate that all ESBL-KP isolates contained two plasmids with the blaCTX-M-15 gene located on the smaller one (~80 kbp). The same ESBL-KP clone was present in follow-up samples for up to 2 years in some patients, and the plasmid carrying the blaCTX-M-15 gene was stable throughout this time period. However, extensive genetic rearrangements within the second plasmid were observed in the optical DNA maps for several of the ESBL-KP isolates. Optical mapping also demonstrated that even though other bacterial clones and species carrying blaCTX-M group 1 genes were found in some neonates, no transfer of resistance plasmids had occurred. The data instead pointed toward unrelated acquisition of ESBL-producing Enterobacteriaceae (EPE). In addition to revealing important information about the specific outbreak, the method presented is a promising tool for surveillance and infection control in clinical settings.
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35
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Ferreira C, Bogas D, Bikarolla SK, Varela AR, Frykholm K, Linheiro R, Nunes OC, Westerlund F, Manaia CM. Genetic variation in the conjugative plasmidome of a hospital effluent multidrug resistant Escherichia coli strain. CHEMOSPHERE 2019; 220:748-759. [PMID: 30611073 DOI: 10.1016/j.chemosphere.2018.12.130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/23/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
Bacteria harboring conjugative plasmids have the potential for spreading antibiotic resistance through horizontal gene transfer. It is described that the selection and dissemination of antibiotic resistance is enhanced by stressors, like metals or antibiotics, which can occur as environmental contaminants. This study aimed at unveiling the composition of the conjugative plasmidome of a hospital effluent multidrug resistant Escherichia coli strain (H1FC54) under different mating conditions. To meet this objective, plasmid pulsed field gel electrophoresis, optical mapping analyses and DNA sequencing were used in combination with phenotype analysis. Strain H1FC54 was observed to harbor five plasmids, three of which were conjugative and two of these, pH1FC54_330 and pH1FC54_140, contained metal and antibiotic resistance genes. Transconjugants obtained in the absence or presence of tellurite (0.5 μM or 5 μM), arsenite (0.5 μM, 5 μM or 15 μM) or ceftazidime (10 mg/L) and selected in the presence of sodium azide (100 mg/L) and tetracycline (16 mg/L) presented distinct phenotypes, associated with the acquisition of different plasmid combinations, including two co-integrate plasmids, of 310 kbp and 517 kbp. The variable composition of the conjugative plasmidome, the formation of co-integrates during conjugation, as well as the transfer of non-transferable plasmids via co-integration, and the possible association between antibiotic, arsenite and tellurite tolerance was demonstrated. These evidences bring interesting insights into the comprehension of the molecular and physiological mechanisms that underlie antibiotic resistance propagation in the environment.
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Affiliation(s)
- Catarina Ferreira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Diana Bogas
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Santosh K Bikarolla
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, SE-412 96, Gothenburg, Sweden
| | - Ana Rita Varela
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Karolin Frykholm
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, SE-412 96, Gothenburg, Sweden
| | - Raquel Linheiro
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Olga C Nunes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, SE-412 96, Gothenburg, Sweden
| | - Célia M Manaia
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal.
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36
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Annealing of ssDNA and compaction of dsDNA by the HIV-1 nucleocapsid and Gag proteins visualized using nanofluidic channels. Q Rev Biophys 2019; 52:e2. [DOI: 10.1017/s0033583518000124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
The nucleocapsid protein NC is a crucial component in the human immunodeficiency virus type 1 life cycle. It functions both in its processed mature form and as part of the polyprotein Gag that plays a key role in the formation of new viruses. NC can protect nucleic acids (NAs) from degradation by compacting them to a dense coil. Moreover, through its NA chaperone activity, NC can also promote the most stable conformation of NAs. Here, we explore the balance between these activities for NC and Gag by confining DNA–protein complexes in nanochannels. The chaperone activity is visualized as concatemerization and circularization of long DNA via annealing of short single-stranded DNA overhangs. The first ten amino acids of NC are important for the chaperone activity that is almost completely absent for Gag. Gag condenses DNA more efficiently than mature NC, suggesting that additional residues of Gag are involved. Importantly, this is the first single DNA molecule study of full-length Gag and we reveal important differences to the truncated Δ-p6 Gag that has been used before. In addition, the study also highlights how nanochannels can be used to study reactions on ends of long single DNA molecules, which is not trivial with competing single DNA molecule techniques.
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37
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Krog J, Alizadehheidari M, Werner E, Bikkarolla SK, Tegenfeldt JO, Mehlig B, Lomholt MA, Westerlund F, Ambjörnsson T. Stochastic unfolding of nanoconfined DNA: Experiments, model and Bayesian analysis. J Chem Phys 2019; 149:215101. [PMID: 30525714 DOI: 10.1063/1.5051319] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nanochannels provide a means for detailed experiments on the effect of confinement on biomacromolecules, such as DNA. Here we introduce a model for the complete unfolding of DNA from the circular to linear configuration. Two main ingredients are the entropic unfolding force and the friction coefficient for the unfolding process, and we describe the associated dynamics by a non-linear Langevin equation. By analyzing experimental data where DNA molecules are photo-cut and unfolded inside a nanochannel, our model allows us to extract values for the unfolding force as well as the friction coefficient for the first time. In order to extract numerical values for these physical quantities, we employ a recently introduced Bayesian inference framework. We find that the determined unfolding force is in agreement with estimates from a simple Flory-type argument. The estimated friction coefficient is in agreement with theoretical estimates for motion of a cylinder in a channel. We further validate the estimated friction constant by extracting this parameter from DNA's center-of-mass motion before and after unfolding, yielding decent agreement. We provide publically available software for performing the required image and Bayesian analysis.
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Affiliation(s)
- Jens Krog
- MEMPHYS-Center for Biomembrane Physics, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense, Denmark
| | | | - Erik Werner
- Department of Physics, Gothenburg University, Gothenburg, Sweden
| | - Santosh Kumar Bikkarolla
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Bernhard Mehlig
- Department of Physics, Gothenburg University, Gothenburg, Sweden
| | - Michael A Lomholt
- MEMPHYS-Center for Biomembrane Physics, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Tobias Ambjörnsson
- Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
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38
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Öz R, Kk S, Westerlund F. A nanofluidic device for real-time visualization of DNA-protein interactions on the single DNA molecule level. NANOSCALE 2019; 11:2071-2078. [PMID: 30644945 DOI: 10.1039/c8nr09023h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single DNA molecule techniques have revolutionized our understanding of DNA-protein interactions. Traditional techniques for such studies have the major drawback that the DNA molecule studied is attached to a bead or a surface. Stretching of DNA molecules in nanofluidic channels has enabled single-molecule studies of DNA-protein interactions without the need of tethering the molecule to a foreign entity. This in turn allows for studying reactions along the whole extension of the molecule, including the free DNA ends. However, existing studies either rely on measurements where all components are mixed before introduction into the nanochannels or where passive diffusion brings the reagents to the confined DNA molecule. We here present a new generation of nanofluidic devices, where active exchange of the local environment within the nanofluidic channel is possible, while keeping the DNA molecule stretched and in confinement. To demonstrate the functionality of this novel device we added different analytes, such as SDS, spermidine and DNase I, to YOYO-1 stained DNA and studied the response in real time. We also performed a FRET-based reaction, where two different analytes were added sequentially to the same DNA molecule. We believe that this design will enable in situ mapping of complex biochemical processes, involving multiple proteins and cofactors, on single DNA molecules as well as other biomacromolecules.
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Affiliation(s)
- Robin Öz
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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39
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Johnning A, Karami N, Tång Hallbäck E, Müller V, Nyberg L, Buongermino Pereira M, Stewart C, Ambjörnsson T, Westerlund F, Adlerberth I, Kristiansson E. The resistomes of six carbapenem-resistant pathogens - a critical genotype-phenotype analysis. Microb Genom 2018; 4. [PMID: 30461373 PMCID: PMC6321870 DOI: 10.1099/mgen.0.000233] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Carbapenem resistance is a rapidly growing threat to our ability to treat refractory bacterial infections. To understand how carbapenem resistance is mobilized and spread between pathogens, it is important to study the genetic context of the underlying resistance mechanisms. In this study, the resistomes of six clinical carbapenem-resistant isolates of five different species – Acinetobacter baumannii, Escherichia coli, two Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas aeruginosa – were characterized using whole genome sequencing. All Enterobacteriaceae isolates and the A. baumannii isolate had acquired a large number of antimicrobial resistance genes (7–18 different genes per isolate), including the following encoding carbapenemases: blaKPC-2, blaOXA-48, blaOXA-72, blaNDM-1, blaNDM-7 and blaVIM-1. In addition, a novel version of blaSHV was discovered. Four new resistance plasmids were identified and their fully assembled sequences were verified using optical DNA mapping. Most of the resistance genes were co-localized on these and other plasmids, suggesting a risk for co-selection. In contrast, five out of six carbapenemase genes were present on plasmids with no or few other resistance genes. The expected level of resistance – based on acquired resistance determinants – was concordant with measured levels in most cases. There were, however, several important discrepancies for four of the six isolates concerning multiple classes of antibiotics. In conclusion, our results further elucidate the diversity of carbapenemases, their mechanisms of horizontal transfer and possible patterns of co-selection. The study also emphasizes the difficulty of using whole genome sequencing for antimicrobial susceptibility testing of pathogens with complex genotypes.
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Affiliation(s)
- Anna Johnning
- 2Centre for Antibiotic Resistance Research, CARe, University of Gothenburg, Gothenburg, Sweden.,1Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Nahid Karami
- 2Centre for Antibiotic Resistance Research, CARe, University of Gothenburg, Gothenburg, Sweden.,3Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erika Tång Hallbäck
- 3Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Vilhelm Müller
- 4Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Lena Nyberg
- 4Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Mariana Buongermino Pereira
- 1Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.,2Centre for Antibiotic Resistance Research, CARe, University of Gothenburg, Gothenburg, Sweden
| | - Callum Stewart
- 5Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Tobias Ambjörnsson
- 5Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Fredrik Westerlund
- 4Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ingegerd Adlerberth
- 2Centre for Antibiotic Resistance Research, CARe, University of Gothenburg, Gothenburg, Sweden.,3Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erik Kristiansson
- 1Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.,2Centre for Antibiotic Resistance Research, CARe, University of Gothenburg, Gothenburg, Sweden
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40
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Interspecies plasmid transfer appears rare in sequential infections with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. Diagn Microbiol Infect Dis 2018; 93:380-385. [PMID: 30527621 DOI: 10.1016/j.diagmicrobio.2018.10.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/29/2018] [Accepted: 10/24/2018] [Indexed: 02/08/2023]
Abstract
From a cohort of 1836 Swedish patients infected with ESBL-producing Enterobacteriaceae (EPE) during 2004-2014, 513 patients with recurrent EPE infection were identified. Only in 14 of the 513 patients was a change of species (ESBL-E. coli to ESBL-K. pneumoniae or vice versa) found between the index and subsequent infection. Eleven sequential urine isolates from 5 of the 14 patients were available for further analysis of possible transfer of ESBL-carrying plasmids. The plasmid content was studied using optical DNA mapping (ODM), PCR-based replicon typing, and ESBL gene sequencing. ODM allowed us to directly compare whole plasmids between isolates and found similar ESBL-carrying plasmids in 3 out of the 5 patients. The ODM results and the rarity in shift of species between ESBL-E. coli and ESBL-K. pneumoniae imply that in recurrent EPE infections interspecies plasmid transfer is uncommon.
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41
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Jiang K, Rocha S, Westling A, Kesarimangalam S, Dorfman KD, Wittung-Stafshede P, Westerlund F. Alpha-Synuclein Modulates the Physical Properties of DNA. Chemistry 2018; 24:15685-15690. [PMID: 30102440 PMCID: PMC6217799 DOI: 10.1002/chem.201803933] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Indexed: 11/06/2022]
Abstract
Fundamental research on Parkinson's disease (PD) most often focuses on the ability of α-synuclein (aS) to form oligomers and amyloids, and how such species promote brain cell death. However, there are indications that aS also plays a gene-regulatory role in the cell nucleus. Here, the interaction between monomeric aS and DNA in vitro has been investigated with single-molecule techniques. Using a nanofluidic channel system, it was discovered that aS binds to DNA and by studying the DNA-protein complexes at different confinements we determined that aS binding increases the persistence length of DNA from 70 to 90 nm at high coverage. By atomic force microscopy it was revealed that at low protein-to-DNA ratio, the aS binding occurs as small protein clusters scattered along the DNA; at high protein-to-DNA ratio, the DNA is fully covered by protein. As DNA-aS interactions may play roles in PD, it is of importance to characterize biophysical properties of such complexes in detail.
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Affiliation(s)
- Kai Jiang
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Sandra Rocha
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Alvina Westling
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Sriram Kesarimangalam
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
| | | | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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42
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Bleha T, Cifra P. Correlation anisotropy and stiffness of DNA molecules confined in nanochannels. J Chem Phys 2018; 149:054903. [PMID: 30089382 DOI: 10.1063/1.5034219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The anisotropy of orientational correlations in DNA molecules confined in cylindrical channels is explored by Monte Carlo simulations using a coarse-grained model of double-stranded (ds) DNA. We find that the correlation function ⟨C(s)⟩⊥ in the transverse (confined) dimension exhibits a region of negative values in the whole range of channel sizes. Such a clear-cut sign of the opposite orientation of chain segments represents a microscopic validation of the Odijk deflection mechanism in narrow channels. At moderate-to-weak confinement, the negative ⟨C(s)⟩⊥ correlations imply a preference of DNA segments for transverse looping. The inclination for looping can explain a reduction of stiffness as well as the enhanced knotting of confined DNA relative to that detected earlier in bulk at some channel sizes. Furthermore, it is shown that the orientational persistence length Por fails to convey the apparent stiffness of DNA molecules in channels. Instead, correlation lengths P∥ and P⊥ in the axial and transverse directions, respectively, encompass the channel-induced modifications of DNA stiffness.
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Affiliation(s)
- Tomáš Bleha
- Polymer Institute, Slovak Academy of Sciences, 84541 Bratislava, Slovakia
| | - Peter Cifra
- Polymer Institute, Slovak Academy of Sciences, 84541 Bratislava, Slovakia
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43
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Schmitt A, Jiang K, Camacho MI, Jonna VR, Hofer A, Westerlund F, Christie PJ, Berntsson RPA. PrgB promotes aggregation, biofilm formation, and conjugation through DNA binding and compaction. Mol Microbiol 2018; 109:291-305. [PMID: 29723434 DOI: 10.1111/mmi.13980] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2018] [Indexed: 12/28/2022]
Abstract
Gram-positive bacteria deploy type IV secretion systems (T4SSs) to facilitate horizontal gene transfer. The T4SSs of Gram-positive bacteria rely on surface adhesins as opposed to conjugative pili to facilitate mating. Enterococcus faecalis PrgB is a surface adhesin that promotes mating pair formation and robust biofilm development in an extracellular DNA (eDNA) dependent manner. Here, we report the structure of the adhesin domain of PrgB. The adhesin domain binds and compacts DNA in vitro. In vivo PrgB deleted of its adhesin domain does not support cellular aggregation, biofilm development and conjugative DNA transfer. PrgB also binds lipoteichoic acid (LTA), which competes with DNA binding. We propose that PrgB binding and compaction of eDNA facilitates cell aggregation and plays an important role in establishment of early biofilms in mono- or polyspecies settings. Within these biofilms, PrgB mediates formation and stabilization of direct cell-cell contacts through alternative binding of cell-bound LTA, which in turn promotes establishment of productive mating junctions and efficient intra- or inter-species T4SS-mediated gene transfer.
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Affiliation(s)
- Andreas Schmitt
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Kai Jiang
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Martha I Camacho
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas 77030, USA
| | - Venkateswara Rao Jonna
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas 77030, USA
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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44
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Lim AE, Lim CY, Lam YC, Taboryski R. Electroosmotic Flow in Microchannel with Black Silicon Nanostructures. MICROMACHINES 2018; 9:E229. [PMID: 30424162 PMCID: PMC6187698 DOI: 10.3390/mi9050229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 02/01/2023]
Abstract
Although electroosmotic flow (EOF) has been applied to drive fluid flow in microfluidic chips, some of the phenomena associated with it can adversely affect the performance of certain applications such as electrophoresis and ion preconcentration. To minimize the undesirable effects, EOF can be suppressed by polymer coatings or introduction of nanostructures. In this work, we presented a novel technique that employs the Dry Etching, Electroplating and Molding (DEEMO) process along with reactive ion etching (RIE), to fabricate microchannel with black silicon nanostructures (prolate hemispheroid-like structures). The effect of black silicon nanostructures on EOF was examined experimentally by current monitoring method, and numerically by finite element simulations. The experimental results showed that the EOF velocity was reduced by 13 ± 7%, which is reasonably close to the simulation results that predict a reduction of approximately 8%. EOF reduction is caused by the distortion of local electric field at the nanostructured surface. Numerical simulations show that the EOF velocity decreases with increasing nanostructure height or decreasing diameter. This reveals the potential of tuning the etching process parameters to generate nanostructures for better EOF suppression. The outcome of this investigation enhances the fundamental understanding of EOF behavior, with implications on the precise EOF control in devices utilizing nanostructured surfaces for chemical and biological analyses.
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Affiliation(s)
- An Eng Lim
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
| | - Chun Yee Lim
- Engineering Cluster, Singapore Institute of Technology, 10 Dover Drive, Singapore 138682, Singapore.
| | - Yee Cheong Lam
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
| | - Rafael Taboryski
- Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
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45
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Kumar R, Chaudhuri A, Kapri R. Sequencing of semiflexible polymers of varying bending rigidity using patterned pores. J Chem Phys 2018; 148:164901. [PMID: 29716219 DOI: 10.1063/1.5036529] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the translocation of a semiflexible polymer through extended pores with patterned stickiness, using Langevin dynamics simulations. We find that the consequence of pore patterning on the translocation time dynamics is dramatic and depends strongly on the interplay of polymer stiffness and pore-polymer interactions. For heterogeneous polymers with periodically varying stiffness along their lengths, we find that variation of the block size of the sequences and the orientation results in large variations in the translocation time distributions. We show how this fact may be utilized to develop an effective sequencing strategy. This strategy involving multiple pores with patterned surface energetics can predict heteropolymer sequences having different bending rigidity to a high degree of accuracy.
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Affiliation(s)
- Rajneesh Kumar
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
| | - Rajeev Kapri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
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46
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Transverse dielectrophoretic-based DNA nanoscale confinement. Sci Rep 2018; 8:5981. [PMID: 29654238 PMCID: PMC5899125 DOI: 10.1038/s41598-018-24132-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/26/2018] [Indexed: 11/19/2022] Open
Abstract
Confinement of single molecules within nanoscale environments is crucial in a range of fields, including biomedicine, genomics, and biophysics. Here, we present a method that can concentrate, confine, and linearly stretch DNA molecules within a single optical field of view using dielectrophoretic (DEP) force. The method can convert an open surface into one confining DNA molecules without a requirement for bonding, hydrodynamic or mechanical components. We use a transverse DEP field between a top coverslip and a bottom substrate, both of which are coated with a transparent conductive material. Both layers are attached using double-sided tape, defining the chamber. The nanofeatures lie at the “floor” and do not require any bonding. With the application of an alternating (AC) electric field (2 Vp-p) between the top and bottom electrodes, a DEP field gradient is established and used to concentrate, confine and linearly extend DNA in nanogrooves as small as 100-nm in width. We also demonstrate reversible loading/unloading of DNA molecules into nanogrooves and nanopits by switching frequency (between 10 kHz to 100 kHz). The technology presented in this paper provides a new method for single-molecule trapping and analysis.
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47
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Lima DC, Nyberg LK, Westerlund F, Batistuzzo de Medeiros SR. Identification and DNA annotation of a plasmid isolated from Chromobacterium violaceum. Sci Rep 2018; 8:5327. [PMID: 29593241 PMCID: PMC5871888 DOI: 10.1038/s41598-018-23708-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/12/2018] [Indexed: 12/18/2022] Open
Abstract
Chromobacterium violaceum is a ß-proteobacterium found widely worldwide with important biotechnological properties and is associated to lethal sepsis in immune-depressed individuals. In this work, we report the discover, complete sequence and annotation of a plasmid detected in C. violaceum that has been unnoticed until now. We used DNA single-molecule analysis to confirm that the episome found was a circular molecule and then proceeded with NGS sequencing. After DNA annotation, we found that this extra-chromosomal DNA is probably a defective bacteriophage of approximately 44 kilobases, with 39 ORFs comprising, mostly hypothetical proteins. We also found DNA sequences that ensure proper plasmid replication and partitioning as well as a toxin addiction system. This report sheds light on the biology of this important species, helping us to understand the mechanisms by which C. violaceum endures to several harsh conditions. This discovery could also be a first step in the development of a DNA manipulation tool in this bacterium.
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Affiliation(s)
- Daniel C Lima
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, Natal, Brazil.,Laboratório de Biologia Molecular e Genômica, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Lena K Nyberg
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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48
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Abstract
Long-read genomic applications, such as genome mapping in nanochannels, require long DNA that is free of small-DNA impurities. We have developed a chip-based system based on entropic trapping that can simultaneously concentrate and purify a long DNA sample under the alternating application of an applied pressure (for sample injection) and an electric field (for filtration and concentration). In contrast, short DNA tends to pass through the filter owing to its comparatively weak entropic penalty for entering the nanoslit. The single-stage prototype developed here, which operates in a continuous pulsatile manner, achieves selectivities of up to 3.5 for λ-phage DNA (48.5 kilobase pairs) compared to a 2 kilobase pair standard based on experimental data for the fraction filtered using pure samples of each species. The device is fabricated in fused silica using standard clean-room methods, making it compatible for integration with long-read genomics technologies.
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Affiliation(s)
- Pranav Agrawal
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave. SE, Minneapolis, MN 55455, USA.
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49
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Werner E, Jain A, Muralidhar A, Frykholm K, St Clere Smithe T, Fritzsche J, Westerlund F, Dorfman KD, Mehlig B. Hairpins in the conformations of a confined polymer. BIOMICROFLUIDICS 2018; 12:024105. [PMID: 29576836 PMCID: PMC5844772 DOI: 10.1063/1.5018787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 02/21/2018] [Indexed: 06/01/2023]
Abstract
If a semiflexible polymer confined to a narrow channel bends around by 180°, the polymer is said to exhibit a hairpin. The equilibrium extension statistics of the confined polymer are well understood when hairpins are vanishingly rare or when they are plentiful. Here, we analyze the extension statistics in the intermediate situation via experiments with DNA coated by the protein RecA, which enhances the stiffness of the DNA molecule by approximately one order of magnitude. We find that the extension distribution is highly non-Gaussian, in good agreement with Monte-Carlo simulations of confined discrete wormlike chains. We develop a simple model that qualitatively explains the form of the extension distribution. The model shows that the tail of the distribution at short extensions is determined by conformations with one hairpin.
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Affiliation(s)
- E Werner
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 96 Göteborg, Sweden
| | - A Jain
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - A Muralidhar
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - K Frykholm
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - T St Clere Smithe
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 96 Göteborg, Sweden
| | - J Fritzsche
- Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - F Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - K D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - B Mehlig
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 96 Göteborg, Sweden
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50
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Gupta D, Bhandari AB, Dorfman KD. Evaluation of Blob Theory for the Diffusion of DNA in Nanochannels. Macromolecules 2018; 51:1748-1755. [PMID: 29599567 DOI: 10.1021/acs.macromol.7b02270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have measured the diffusivity of λ-DNA molecules in approximately square nanochannels with effective sizes ranging from 117 nm to 260 nm at moderate ionic strength. The experimental results do not agree with the non-draining scaling predicted by blob theory. Rather, the data are consistent with the predictions of previous simulations of the Kirkwood diffusivity of a discrete wormlike chain model, without the need for any fitting parameters.
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Affiliation(s)
- Damini Gupta
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
| | - Aditya Bikram Bhandari
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
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