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Single molecule imaging

Takashi Kumagai, Janina N Ladenthin, Yair Litman, Mariana Rossi, Leonhard Grill, Sylwester Gawinkowski, Jacek Waluk, Mats Persson
Tautomerization in single porphycene molecules is investigated on Cu(111), Ag(111), and Au(111) surfaces by a combination of low-temperature scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations. It is revealed that the trans configuration is the thermodynamically stable form of porphycene on Cu(111) and Ag(111), whereas the cis configuration occurs as a meta-stable form. The trans → cis or cis → trans conversion on Cu(111) can be induced in an unidirectional fashion by injecting tunneling electrons from the STM tip or heating the surface, respectively...
March 14, 2018: Journal of Chemical Physics
Sebastian Trippel, Joss Wiese, Terry Mullins, Jochen Küpper
Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D ⟩ ≥ 0...
March 14, 2018: Journal of Chemical Physics
Nelly Siller, Jens Kuhle, Muthuraman Muthuraman, Christian Barro, Timo Uphaus, Sergiu Groppa, Ludwig Kappos, Frauke Zipp, Stefan Bittner
BACKGROUND: Monitoring neuronal injury remains one key challenge in early relapsing-remitting multiple sclerosis (RRMS) patients. Upon axonal damage, neurofilament - a major component of the neuro-axonal cytoskeleton - is released into the cerebrospinal fluid (CSF) and subsequently peripheral blood. OBJECTIVE: To investigate the relevance of serum neurofilament light chain (sNfL) for acute and chronic axonal damage in early RRMS. METHODS: sNfL levels were determined in 74 patients (63 therapy-naive) with recently diagnosed clinically isolated syndrome (CIS) or RRMS using Single Molecule Array technology...
March 1, 2018: Multiple Sclerosis: Clinical and Laboratory Research
Fredrik Dahl, Olle Ericsson, Olof Karlberg, Filip Karlsson, Mathias Howell, Fredrik Persson, Fredrik Roos, Johan Stenberg, Tarja Ahola, Ida Alftrén, Björn Andersson, Emelie Barkenäs, Birgit Brandner, Jenny Dahlberg, Sara Elfman, Magnus Eriksson, Per-Ola Forsgren, Niels Francois, Anna Gousseva, Faizan Hakamali, Åsa Janfalk-Carlsson, Henrik Johansson, Johanna Lundgren, Atefeh Mohsenchian, Linus Olausson, Simon Olofsson, Atif Qureshi, Björn Skarpås, Anna Sävneby, Eva Åström, Ove Öhman, Magnus Westgren, Helena Kopp-Kallner, Aino Fianu-Jonasson, Argyro Syngelaki, Kypros Nicolaides
Cell-free DNA analysis is becoming adopted for first line aneuploidy screening, however for most healthcare programs, cost and workflow complexity is limiting adoption of the test. We report a novel cost effective method, the Vanadis NIPT assay, designed for high precision digitally-enabled measurement of chromosomal aneuploidies in maternal plasma. Reducing NIPT assay complexity is achieved by using novel molecular probe technology that specifically label target chromosomes combined with a new readout format using a nanofilter to enrich single molecules for imaging and counting without DNA amplification, microarrays or sequencing...
March 14, 2018: Scientific Reports
Paola Bonaccorsi, Teresa Papalia, Anna Barattucci, Tania M G Salerno, Camillo Rosano, Patrizio Castagnola, Maurizio Viale, Massimiliano Monticone, Sebastiano Campagna, Fausto Puntoriero
We prepared a bichromophoric species 1, made of two different bodipy dyes bridged by a d-galactose unit. 1 exhibits different emission spectra when located in different compartments of biological systems, independently of its concentration. This is an unprecedented feature for a single multicomponent molecule and is due to the dependence on the environment of the photoinduced energy transfer process occurring between its bodipy subunits. Therefore, 1 can give useful information about cell composition and ultimately anomalies without requiring the simultaneous use of several different compounds, paving the way for the use of environment-controlled inter-component energy transfer to gain cell information based on luminescence imaging...
March 14, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Junwei Shi, Thirupandiyur S Udayakumar, Keying Xu, Nesrin Dogan, Alan Pollack, Yidong Yang
PURPOSE: The image guided small animal arc radiation treatment platform has adopted onboard cone beam computed tomography and bioluminescence tomography (BLT). We used BLT to guide irradiation delivery and quantitatively assess irradiation-induced tumor response. METHODS AND MATERIALS: BLT was first validated on a tissue-simulating phantom, where the internal chemiluminescent liquid had a constant volume while its luminescence intensity gradually decayed. Then, in vivo experiments were performed on BALB/c mice orthotopically inoculated with 4T1 breast carcinoma cells expressing luciferase...
February 2, 2018: International Journal of Radiation Oncology, Biology, Physics
Lukas Nejdl, Andrea Moravanska, Kristyna Smerkova, Filip Mravec, Sona Krizkova, Adam Pomorski, Artur Krężel, Mirek Macka, Vojtech Adam, Marketa Vaculovicova
A capillary electrophoretic (CE) method using a short-sweep approach and laser-induced fluorescence (LIF) detection (ShortSweepCE-LIF) was developed for determination of Zn2+ and Cd2+ as complexes with highly selective and sensitive fluorescent probe FluoZin-3. The ShortSweepCE-LIF method, established in this work, can be used for examining competitive Zn2+ and Cd2+ binding properties of metalloproteins or peptides. The parameters including background electrolyte composition, injection pressure and time as well as separation voltage were investigated...
August 9, 2018: Analytica Chimica Acta
Hao Xiao, Mingyue Sun, Ruiyue Zhao, Haiyan Hong, Aili Zhang, Shuxian Zhang, Futao Liu, Yan Zhang, Yajing Liu, Lin Zhu, Hank F Kung, Jinping Qiao
Cassette dosing is also known as N-in-One dosing: several compounds are simultaneously administrated to a single animal and then the samples are rapidly detected by LC-MS/MS. This approach is a successful strategy to enhance the efficiency of drug discovery and reduce animal usage. However, no report on the utility of the cassette approach in radiotracer discovery has appeared in the literature. This study designed a cassette microdose with LC-MS/MS method to enhance the throughput for screening radiopharmaceutical biodistribution in the rat brain directly...
March 3, 2018: Journal of Pharmaceutical and Biomedical Analysis
Adam C Sedgwick, Tony D James
Chemosensors are compounds that incorporate a receptor unit and a reporter unit in a single molecule. A chemosensor transforms the action of binding to a specific analyte into a readable signal. Chemosensors have enabled the study of molecular interactions in a range of different media and interfaces. This offers a non-invasive approach to observe living biological samples in real time without the sample being destroyed. For example, fluorescence-based chemosensors are designed to have a high sensitivity and specificity, allowing them to interact selectively with a single target within a complex biological environment...
March 2018: ChemistryOpen
Joerg Schnitzbauer, Yina Wang, Shijie Zhao, Matthew Bakalar, Tulip Nuwal, Baohui Chen, Bo Huang
Superresolution images reconstructed from single-molecule localizations can reveal cellular structures close to the macromolecular scale and are now being used routinely in many biomedical research applications. However, because of their coordinate-based representation, a widely applicable and unified analysis platform that can extract a quantitative description and biophysical parameters from these images is yet to be established. Here, we propose a conceptual framework for correlation analysis of coordinate-based superresolution images using distance histograms...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Nicola Salvarese, Barbara Spolaore, Selena Marangoni, Anna Pasin, Alessandro Galenda, Sergio Tamburini, Gianfranco Cicoria, Fiorenzo Refosco, Cristina Bolzati
An assessment study involving the use of the transglutaminase (TGase) conjugation method and the nitride-technetium-99m labelling on a bis(thiosemicarbazone) (BTS) bifunctional chelating agent is presented. The previously described chelator diacetyl-2-(N4 -methyl-3-thiosemicarbazone)-3-(N4 -amino-3-thiosemicarbazone), H2 ATSM/A, has been functionalized with 6-aminohexanoic acid (ε-Ahx) to generate the bifunctional chelating agent diacetyl-2-(N4 -methyl-3-thiosemicarbazone)-3-[N4 -(amino)-(6-aminohexanoic acid)-3-thiosemicarbazone], H2 ATSM/A-ε-Ahx (1), suitable for conjugation to glutamine (Gln) residues of bioactive molecules via TGase...
March 2, 2018: Journal of Inorganic Biochemistry
Hye-Yeong Kim, Xiaolei Wang, Rui Kang, Daolin Tang, Brian A Boone, Herbert J Zeh, Michael T Lotze, W Barry Edwards
Noninvasive detection of both early pancreatic neoplasia and metastases could enhance strategies to improve patient survival in this disease that is notorious for an extremely poor prognosis. There are almost no identifiable targets for non-invasive diagnosis by positron emission tomography (PET) for patients with pancreatic ductal adenocarcinoma (PDAC). Over-expression of the receptor for advanced glycation end products (RAGE) is found on the cell surface of both pre-neoplastic lesions and invasive PDAC. Here, a RAGE-specific single chain (scFv) was developed, specific for PET imaging in syngeneic mouse models of PDAC...
2018: PloS One
Margarete Poppelreuther, Simone Sander, Fadil Minden, Marina S Dietz, Tarik Exner, Chen Du, Ingrid Zhang, Friedrich Ehehalt, Laura Knüppel, Susanne Domschke, Anna Badenhop, Sarah Staudacher, Robert Ehehalt, Wolfgang Stremmel, Christoph Thiele, Mike Heilemann, Joachim Füllekrug
ACSL3 is the only long chain fatty acyl-CoA synthetase consistently found on growing and mature lipid droplets (LDs), suggesting that this specific localization has biological relevance. Current models for LD growth propose that triglycerides are synthesized by enzymes at the LD surface, with activated fatty acids provided by LD localized ACSL3, thus allowing growth independent of the ER. Here, we tested this hypothesis by quantifying ACSL3 on LDs from human A431 cells. RNAi of ACSL3 reduced the oleoyl-CoA synthetase activity by 83%, suggesting that ACSL3 is by far the dominant enzyme of A431 cells...
March 8, 2018: Biochimica et Biophysica Acta
Yuanwei Fan, Graham M Burkart, Ram Dixit
The contribution of microtubule tip dynamics to the assembly and function of plant microtubule arrays remains poorly understood. Here, we report that the Arabidopsis SPIRAL2 (SPR2) protein modulates the dynamics of the acentrosomal cortical microtubule plus and minus ends in an opposing manner. Live imaging of a functional SPR2-mRuby fusion protein revealed that SPR2 shows both microtubule plus- and minus-end tracking activity in addition to localization at microtubule intersections and along the lattice...
February 28, 2018: Current Biology: CB
Thomas Orré, Amine Mehidi, Sophie Massou, Olivier Rossier, Grégory Giannone
To get a complete understanding of cell migration, it is critical to study its orchestration at the molecular level. Since the recent developments in single-molecule imaging, it is now possible to study molecular phenomena at the single-molecule level inside living cells. In this chapter, we describe how such approaches have been and can be used to decipher molecular mechanisms involved in cell migration.
2018: Methods in Molecular Biology
Xiaowei Wang, Amy Kate Searle, Jan David Hohmann, Ao Leo Liu, Meike-Kristin Abraham, Jathushan Palasubramaniam, Bock Lim, Yu Yao, Maria Wallert, Eefang Yu, Yung-Chih Chen, Karlheinz Peter
Abdominal aortic aneurysm (AAA) is an often deadly disease without medical, non-invasive treatment options. The upregulation of vascular cell adhesion molecule-1 (VCAM-1) on aortic endothelium provides an early target epitope for a novel biotechnological theranostic approach. MicroRNA-126 was used as a therapeutic agent, based on its capability to downregulate VCAM-1 expression in endothelial cells and thereby reduces leukocyte adhesion and exerts anti-inflammatory effects. Ultrasound microbubbles were chosen as carriers, allowing both molecular imaging as well as targeted therapy of AAA...
February 16, 2018: Molecular Therapy: the Journal of the American Society of Gene Therapy
William Beckman, Ilona M Vuist, Hermannus Kempe, Pernette J Verschure
Single-molecule RNA fluorescent in situ hybridization (smRNA FISH) allows for the visualization, localization, and quantification of RNA transcripts within individual cells and tissues using custom-designed fluorescently labeled oligonucleotide probes. Here we describe a protocol for the preparation, imaging, and analysis of a smRNA FISH experiment that can be applied to any RNA of choice. We also provide insights as to how this powerful tool can be used to study epigenetic regulation, for example, following the epigenetic editing of genes...
2018: Methods in Molecular Biology
Rajeev Yadav, H Peter Lu
The N-methyl-d-aspartate (NMDA) receptor ion-channel is activated by the binding of ligands, along with the application of action potential, important for synaptic transmission and memory functions. Despite substantial knowledge of the structure and function, the gating mechanism of the NMDA receptor ion channel for electric on-off signals is still a topic of debate. We investigate the NMDA receptor partition distribution and the associated channel's open-close electric signal trajectories using a combined approach of correlating single-molecule fluorescence photo-bleaching, single-molecule super-resolution imaging, and single-channel electric patch-clamp recording...
March 8, 2018: Physical Chemistry Chemical Physics: PCCP
Christopher R Hackley, Esteban O Mazzoni, Justin Blau
Genetically encoded fluorescent sensors enable cell-specific measurements of ions and small molecules in real time. Cyclic adenosine monophosphate (cAMP) is one of the most important signaling molecules in virtually all cell types and organisms. We describe cAMPr, a new single-wavelength cAMP sensor. We developed cAMPr in bacteria and embryonic stem cells and validated the sensor in mammalian neurons in vitro and in Drosophila circadian pacemaker neurons in intact brains. Comparison with other single-wavelength cAMP sensors showed that cAMPr improved the quantitative detection of cAMP abundance...
March 6, 2018: Science Signaling
Nicolas Pavillon, Alison J Hobro, Shizuo Akira, Nicholas I Smith
We present a method enabling the noninvasive study of minute cellular changes in response to stimuli, based on the acquisition of multiple parameters through label-free microscopy. The retrieved parameters are related to different attributes of the cell. Morphological variables are extracted from quantitative phase microscopy and autofluorescence images, while molecular indicators are retrieved via Raman spectroscopy. We show that these independent parameters can be used to build a multivariate statistical model based on logistic regression, which we apply to the detection at the single-cell level of macrophage activation induced by lipopolysaccharide (LPS) exposure and compare their respective performance in assessing the individual cellular state...
March 6, 2018: Proceedings of the National Academy of Sciences of the United States of America
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