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Article ; Online: Enhanced resonance energy transfer in gold nanoparticles bifunctionalized by tryptophan and riboflavin and its application in fluorescence bioimaging.

Pajović, Jelena D / Dojčilović, Radovan J / Kaščáková, Slávka / Réfrégiers, Matthieu / Božanić, Dušan K / Djoković, Vladimir

Colloids and surfaces. B, Biointerfaces

2023 Volume 227, Page(s) 113340

Abstract: Gold nanoparticles were functionalized by amino acid tryptophan and vitamin riboflavin - a resonance energy transfer (RET) pair of biomolecules. The presence of the gold nanoparticles resulted in 65% increase in RET efficiency. Because of enhanced RET ... ...

Abstract	Gold nanoparticles were functionalized by amino acid tryptophan and vitamin riboflavin - a resonance energy transfer (RET) pair of biomolecules. The presence of the gold nanoparticles resulted in 65% increase in RET efficiency. Because of enhanced RET efficiency, the photobleaching dynamics of the fluorescent molecules at the surface of the nanoparticles is different from that of molecules in solution. The observed effect was used for detection of the functionalized nanoparticles within biological material rich with autofluorescent species. Synchrotron radiation deep-ultraviolet fluorescence microscopy is used to study the photobleaching dynamics of the fluorescence centers within human hepatocellular carcinoma Huh7.5.1 cells incubated with the nanoparticles. The fluorescent centers were classified according to their photobleaching dynamics, which enabled the discrimination of the cell areas where the accumulation of the nanoparticles takes place, even though the particles were smaller than the spatial resolution of the images.
MeSH term(s)	Humans ; Metal Nanoparticles/chemistry ; Tryptophan/chemistry ; Gold/chemistry ; Riboflavin ; Fluorescence Resonance Energy Transfer/methods ; Fluorescent Dyes/chemistry
Chemical Substances	Tryptophan (8DUH1N11BX) ; Gold (7440-57-5) ; Riboflavin (TLM2976OFR) ; Fluorescent Dyes
Language	English
Publishing date	2023-05-12
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	1500523-9
ISSN	1873-4367 ; 0927-7765
ISSN (online)	1873-4367
ISSN	0927-7765
DOI	10.1016/j.colsurfb.2023.113340
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Article: Fluorescence microscopy and photodielectric characterization studies of the composite films of polyvinyl alcohol and tryptophan functionalized silver nanoparticles

Božanić, Dušan K. / Dojčilović, Radovan / Pajović, Jelena D. / Tošić, Dragana / Dudić, Duško / Réfrégiers, Matthieu / Djoković, Vladimir

Colloids and surfaces. 2022 Feb. 05, v. 634

2022

Abstract: Fluorescent nanocomposite films were prepared by solution mixing of polyvinyl alcohol (PVA) and tryptophan functionalized silver (AgTrp) nanoparticles. Synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging was used to follow the distribution ...

Abstract	Fluorescent nanocomposite films were prepared by solution mixing of polyvinyl alcohol (PVA) and tryptophan functionalized silver (AgTrp) nanoparticles. Synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging was used to follow the distribution of AgTrp nanoparticles within the polymer matrix. Pronounced growth of dendrite-like structures in the presence of AgTrp nanoparticles was confirmed by bright field and fluorescence imaging as well as with atomic force microscopies. Both tryptophan and AgTrp nanoparticles influence thermal properties of the matrix. Differential scanning calorimetry measurements showed that they reduce crystallinity and significantly increase the glass transition temperature of PVA (in the case of PVA-AgTrp film the Tg increases by ~20 °C). Dielectric properties of the films were studied under two different conditions (dark and illumination). The illumination with 250 nm light induces a significant increase in conductance of the PVA-AgTrp nanocomposite. The relative changes, with respect to the conductance measured in the dark, were almost ~200%.
Keywords	crystal structure ; fluorescence ; fluorescence microscopy ; glass transition temperature ; lighting ; nanocomposites ; nanosilver ; polyvinyl alcohol ; silver ; tryptophan
Language	English
Dates of publication	2022-0205
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1500517-3
ISSN	0927-7757
ISSN	0927-7757
DOI	10.1016/j.colsurfa.2021.128050
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Article ; Online: Multi-Technique Characterization of 3.45 Ga Microfossils on Earth: A Key Approach to Detect Possible Traces of Life in Returned Samples from Mars.

Clodoré, Laura / Foucher, Frédéric / Hickman-Lewis, Keyron / Sorieul, Stéphanie / Jouve, Jean / Réfrégiers, Matthieu / Collet, Guillaume / Petoud, Stéphane / Gratuze, Bernard / Westall, Frances

Astrobiology

2024 Volume 24, Issue 2, Page(s) 190–226

Abstract: The NASA Mars 2020 Perseverance rover is actively exploring Jezero crater to conduct analyses on igneous and sedimentary rock targets from outcrops located on the crater floor (Máaz and Séítah formations) and from the delta deposits, respectively. The ... ...

Abstract	The NASA Mars 2020 Perseverance rover is actively exploring Jezero crater to conduct analyses on igneous and sedimentary rock targets from outcrops located on the crater floor (Máaz and Séítah formations) and from the delta deposits, respectively. The rock samples collected during this mission will be recovered during the Mars Sample Return mission, which plans to bring samples back to Earth in the 2030s to conduct in-depth studies using sophisticated laboratory instrumentation. Some of these samples may contain traces of ancient martian life that may be particularly difficult to detect and characterize because of their morphological simplicity and subtle biogeochemical expressions. Using the volcanic sediments of the 3.45 Ga Kitty's Gap Chert (Pilbara, Australia), containing putative early life forms (chemolithotrophs) and considered as astrobiological analogues for potential early Mars organisms, we document the steps required to demonstrate the syngenicity and biogenicity of such biosignatures using multiple complementary analytical techniques to provide information at different scales of observation. These include sedimentological, petrological, mineralogical, and geochemical analyses to demonstrate macro- to microscale habitability. New approaches, some unavailable at the time of the original description of these features, are used to verify the syngenicity and biogenicity of the purported fossil chemolithotrophs. The combination of elemental (proton-induced X-ray emission spectrometry) and molecular (deep-ultraviolet and Fourier transform infrared) analyses of rock slabs, thin sections, and focused ion beam sections reveals that the carbonaceous matter present in the samples is enriched in trace metals (
MeSH term(s)	Extraterrestrial Environment/chemistry ; Geologic Sediments/chemistry ; Mars ; Exobiology ; Fossils
Language	English
Publishing date	2024-02-23
Publishing country	United States
Document type	Journal Article
ZDB-ID	2047736-3
ISSN	1557-8070 ; 1531-1074
ISSN (online)	1557-8070
ISSN	1531-1074
DOI	10.1089/ast.2023.0089
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Article ; Online: Biological effects of the loss of homochirality in a multicellular organism.

Banreti, Agnes / Bhattacharya, Shayon / Wien, Frank / Matsuo, Koichi / Réfrégiers, Matthieu / Meinert, Cornelia / Meierhenrich, Uwe / Hudry, Bruno / Thompson, Damien / Noselli, Stéphane

Nature communications

2022 Volume 13, Issue 1, Page(s) 7059

Abstract: Homochirality is a fundamental feature of all known forms of life, maintaining biomolecules (amino-acids, proteins, sugars, nucleic acids) in one specific chiral form. While this condition is central to biology, the mechanisms by which the adverse ... ...

Abstract	Homochirality is a fundamental feature of all known forms of life, maintaining biomolecules (amino-acids, proteins, sugars, nucleic acids) in one specific chiral form. While this condition is central to biology, the mechanisms by which the adverse accumulation of non-L-α-amino-acids in proteins lead to pathophysiological consequences remain poorly understood. To address how heterochirality build-up impacts organism's health, we use chiral-selective in vivo assays to detect protein-bound non-L-α-amino acids (focusing on aspartate) and assess their functional significance in Drosophila. We find that altering the in vivo chiral balance creates a 'heterochirality syndrome' with impaired caspase activity, increased tumour formation, and premature death. Our work shows that preservation of homochirality is a key component of protein function that is essential to maintain homeostasis across the cell, tissue and organ level.
MeSH term(s)	Stereoisomerism ; Amino Acids/chemistry ; Proteins/chemistry
Chemical Substances	Amino Acids ; Proteins
Language	English
Publishing date	2022-11-18
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-022-34516-x
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Article: Disordered-Ordered Protein Binary Classification by Circular Dichroism Spectroscopy.

Micsonai, András / Moussong, Éva / Murvai, Nikoletta / Tantos, Ágnes / Tőke, Orsolya / Réfrégiers, Matthieu / Wien, Frank / Kardos, József

Frontiers in molecular biosciences

2022 Volume 9, Page(s) 863141

Abstract: Intrinsically disordered proteins lack a stable tertiary structure and form dynamic conformational ensembles due to their characteristic physicochemical properties and amino acid composition. They are abundant in nature and responsible for a large ... ...

Abstract	Intrinsically disordered proteins lack a stable tertiary structure and form dynamic conformational ensembles due to their characteristic physicochemical properties and amino acid composition. They are abundant in nature and responsible for a large variety of cellular functions. While numerous bioinformatics tools have been developed for
Language	English
Publishing date	2022-05-03
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2814330-9
ISSN	2296-889X
ISSN	2296-889X
DOI	10.3389/fmolb.2022.863141
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Article ; Online: A framework for dissecting affinities of multidrug efflux transporter AcrB to fluoroquinolones.

Vergalli, Julia / Chauvet, Hugo / Oliva, Francesco / Pajović, Jelena / Malloci, Giuliano / Vargiu, Attilio Vittorio / Réfrégiers, Matthieu / Ruggerone, Paolo / Pagès, Jean-Marie

Communications biology

2022 Volume 5, Issue 1, Page(s) 1062

Abstract: Sufficient concentration of antibiotics close to their target is key for antimicrobial action. Among the tools exploited by bacteria to reduce the internal concentration of antibiotics, multidrug efflux pumps stand out for their ability to capture and ... ...

Abstract	Sufficient concentration of antibiotics close to their target is key for antimicrobial action. Among the tools exploited by bacteria to reduce the internal concentration of antibiotics, multidrug efflux pumps stand out for their ability to capture and expel many unrelated compounds out of the cell. Determining the specificities and efflux efficiency of these pumps towards their substrates would provide quantitative insights into the development of antibacterial strategies. In this light, we developed a competition efflux assay on whole cells, that allows measuring the efficacy of extrusion of clinically used quinolones in populations and individual bacteria. Experiments reveal the efficient competitive action of some quinolones that restore an active concentration of other fluoroquinolones. Computational methods show how quinolones interact with the multidrug efflux transporter AcrB. Combining experiments and computations unveils a key molecular mechanism acting in vivo to detoxify bacterial cells. The developed assay can be generalized to the study of other efflux pumps.
MeSH term(s)	Anti-Bacterial Agents/chemistry ; Anti-Bacterial Agents/pharmacology ; Drug Resistance, Multiple, Bacterial ; Escherichia coli Proteins/metabolism ; Fluoroquinolones/pharmacology ; Membrane Transport Proteins ; Multidrug Resistance-Associated Proteins/chemistry
Chemical Substances	Anti-Bacterial Agents ; Escherichia coli Proteins ; Fluoroquinolones ; Membrane Transport Proteins ; Multidrug Resistance-Associated Proteins
Language	English
Publishing date	2022-10-06
Publishing country	England
Document type	Journal Article
ISSN	2399-3642
ISSN (online)	2399-3642
DOI	10.1038/s42003-022-04024-1
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Article: Evolution of the flax cell wall composition during development and after gravitropism by synchrotron fluorescence imaging

Beaugrand, Johnny / Goudenhooft, Camille / Alvarado, Camille / Devaux, Marie-Françoise / Rivard, Camille / Durand, Sylvie / Chauvet, Hugo / Réfrégiers, Matthieu / Jamme, Frédéric / Guillon, Fabienne / Baley, Christophe / Bourmaud, Alain

Industrial crops and products. 2022 Jan., v. 175

2022

Abstract: Flax (Linum usitatissimum) lodging is an issue of great interest for industrial producers due to its economic impact; despite a strong varietal selection over around one century, this plant remains sensitive to lodging which represents a main technico- ... ...

Abstract	Flax (Linum usitatissimum) lodging is an issue of great interest for industrial producers due to its economic impact; despite a strong varietal selection over around one century, this plant remains sensitive to lodging which represents a main technico-economic issue. To better understand lodging effects at the cell wall and stem scale, the cell wall composition dynamics during cell wall development and after a 90° tilt bending stress is reported. Deep-UltraViolet (DUV) fluorescence emission dynamics recorded at the Synchrotron SOLEIL-DISCO beamline by multichannel autofluorescence imaging is addressed for five cellular wall types of flax stems after an artificially induced gravitropic reaction. The quantitative fluorescent profile intensities were computed after image analysis, and compared to the control flax stems, we reported a systematically higher average intensity fluorescence (probability >95%) for the 90° tilted plants. Moreover, the average stem fluorescence intensities were significantly different among the 3 developmental stages, with the youngest stage (VS) exhibiting on average 30% and 20% less fluorescence than the medium (FG) and mature (M) stages, respectively. The flax stem response to tilt impacted the xylem cellular type, while the bast fibres were arguably less affected by the protein, and hydroxycinnamate contents. A complementary investigation was carried out on bast fibres by infrared microspectroscopy to explore the polysaccharide components not detected in DUV fluorescence, and significant modifications were monitored.
Keywords	Linum usitatissimum ; cell wall components ; cell walls ; economic impact ; flax ; fluorescence ; gravitropism ; image analysis ; polysaccharides ; probability ; xylem
Language	English
Dates of publication	2022-01
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1132158-1
ISSN	1872-633X ; 0926-6690
ISSN (online)	1872-633X
ISSN	0926-6690
DOI	10.1016/j.indcrop.2021.114256
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Article ; Online: Synchrotron multimodal imaging in a whole cell reveals lipid droplet core organization.

Jamme, Frédéric / Cinquin, Bertrand / Gohon, Yann / Pereiro, Eva / Réfrégiers, Matthieu / Froissard, Marine

Journal of synchrotron radiation

2020 Volume 27, Issue Pt 3, Page(s) 772–778

Abstract: A lipid droplet (LD) core of a cell consists mainly of neutral lipids, triacylglycerols and/or steryl esters (SEs). The structuration of these lipids inside the core is still under debate. Lipid segregation inside LDs has been observed but is sometimes ... ...

Abstract	A lipid droplet (LD) core of a cell consists mainly of neutral lipids, triacylglycerols and/or steryl esters (SEs). The structuration of these lipids inside the core is still under debate. Lipid segregation inside LDs has been observed but is sometimes suggested to be an artefact of LD isolation and chemical fixation. LD imaging in their native state and in unaltered cellular environments appears essential to overcome these possible technical pitfalls. Here, imaging techniques for ultrastructural study of native LDs in cellulo are provided and it is shown that LDs are organized structures. Cryo soft X-ray tomography and deep-ultraviolet (DUV) transmittance imaging are showing a partitioning of SEs at the periphery of the LD core. Furthermore, DUV transmittance and tryptophan/tyrosine auto-fluorescence imaging on living cells are combined to obtain complementary information on cell chemical contents. This multimodal approach paves the way for a new label-free organelle imaging technique in living cells.
MeSH term(s)	Cryoelectron Microscopy ; Lipid Droplets/chemistry ; Lipid Droplets/ultrastructure ; Multimodal Imaging ; Saccharomyces cerevisiae ; Synchrotrons ; Triglycerides/chemistry
Chemical Substances	Triglycerides
Language	English
Publishing date	2020-04-23
Publishing country	United States
Document type	Journal Article
ZDB-ID	2021413-3
ISSN	1600-5775 ; 0909-0495
ISSN (online)	1600-5775
ISSN	0909-0495
DOI	10.1107/S1600577520003847
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Article: Synchrotron Deep-UV Photoluminescence Imaging for the Submicrometer Analysis of Chemically Altered Zinc White Oil Paints

Hageraats, Selwin / Keune, Katrien / Réfrégiers, Matthieu / van Loon, Annelies / Berrie, Barbara / Thoury, Mathieu

Analytical chemistry. 2019 Oct. 29, v. 91, no. 23

2019

Abstract: Zinc oxide (ZnO) is a II–VI semiconductor that has been used for the last 150 years as an artists’ pigment under the name of zinc white. Oil paints containing zinc white are known to be prone to the formation of zinc carboxylates, which can cause ... ...

Abstract	Zinc oxide (ZnO) is a II–VI semiconductor that has been used for the last 150 years as an artists’ pigment under the name of zinc white. Oil paints containing zinc white are known to be prone to the formation of zinc carboxylates, which can cause protrusions and mechanical failure. In this article, it is demonstrated how a multispectral synchrotron-based deep-UV photoluminescence microimaging technique can be used to show the distribution of zinc soaps on the submicrometer scale and how this information is used to further the understanding of zinc white degradation processes in oil paint. The technique is based on the luminescence of zinc soaps in the near-UV (∼3.65 eV) upon excitation in the deep-UV (4.51 eV), involving transitions that are argued to subsequently involve ligand-to-metal and metal-to-ligand charge transfer with intermediate structural reconfiguration. Because the primary emission peak lies at a higher energy than the band gap of ZnO (3.3 eV), the signal can easily be isolated from the pigment’s very intense band gap and trap state emission by employing a multispectral acquisition approach. Moreover, analysis at such short wavelengths, in combination with a UV-transparent optical setup, allows for lateral resolution on the order of 200 nm to be obtained. The unprecedented capabilities of the microimaging technique are illustrated by showing its application to the study of a historical cross section from an early 20th century painting by Piet Mondrian. Revealing the submicrometer distribution of crystalline zinc soaps in this cross section provides new insights that suggest that microfissures, the starting points of paint delamination, are the result of an overall expansion of a heavily saponified zinc white layer.
Keywords	delamination ; energy ; image analysis ; oils ; paints ; photoluminescence ; semiconductors ; soaps ; ultraviolet radiation ; wavelengths ; zinc ; zinc oxide
Language	English
Dates of publication	2019-1029
Size	p. 14887-14895.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.9b02443
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Article ; Online: Novel markers to early detect degradation on cellulose nitrate-based heritage at the submicrometer level using synchrotron UV-VIS multispectral luminescence.

Neves, Artur / Ramos, Ana Maria / Callapez, Maria Elvira / Friedel, Robert / Réfrégiers, Matthieu / Thoury, Mathieu / Melo, Maria João

Scientific reports

2021 Volume 11, Issue 1, Page(s) 20208

Abstract: Cellulose nitrate (CN) is an intrinsically unstable material that puts at risk the preservation of a great variety of objects in heritage collections, also posing threats to human health. For this reason, a detailed investigation of its degradation ... ...

Abstract	Cellulose nitrate (CN) is an intrinsically unstable material that puts at risk the preservation of a great variety of objects in heritage collections, also posing threats to human health. For this reason, a detailed investigation of its degradation mechanisms is necessary to develop sustainable conservation strategies. To investigate novel probes of degradation, we implemented deep UV photoluminescence micro spectral-imaging, for the first time, to characterize a corpus of historical systems composed of cellulose nitrate. The analysis of cinematographic films and everyday objects dated from the nineteenth c./early twentieth c. (Perlov's collection), as well as of photo-aged CN and celluloid references allowed the identification of novel markers that correlate with different stages of CN degradation in artworks, providing insight into the role played by plasticizers, fillers, and other additives in stability. By comparison with photoaged references of CN and celluloid (70% CN and 30% camphor), it was possible to correlate camphor concentration with a higher rate of degradation of the cinematographic films. Furthermore, the present study investigates, at the sub-microscale, materials heterogeneity that correlates to the artworks' history, associating the different emission profiles of zinc oxide to specific color formulations used in the late nineteenth and early twentieth centuries.
Language	English
Publishing date	2021-10-12
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-021-99058-6
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