Articles

Impact des feux de brousse sur la biodiversité et la sécurité alimentaire : évaluation des effets écologiques, agronomiques et socio-économiques
- Dzokom Alexis
Sahel Nature Consulting Revue, Sahel Nature Consulting Revue (March 2025) , 2026, 09 (02), pp.1-14 . <div><p>Les feux de brousse constituent un phénomène récurrent dans de nombreuses régions sahéliennes et savanes, influençant profondément les écosystèmes et les moyens de subsistance humains. Cette étude analyse les impacts écologiques des feux de brousse sur la biodiversité (flore et faune) et leur incidence sur la sécurité alimentaire des populations locales. En combinant des approches écologiques, agronomiques et socio-économiques, nous évaluons comment les brûlis affectent la composition des espèces, la productivité des sols, les rendements agricoles et les stratégies d'adaptation des communautés. Les résultats montrent une perte significative de 28 % de biodiversité, une réduction de la résilience écosystémique atteignant jusqu'à 35 % un an après les incendies saisonniers, et des effets négatifs sur les rendements agricoles, avec une réduction moyenne des rendements de 22 % dans les parcelles situées à proximité des zones brûlées, menaçant directement la sécurité alimentaire. Les données suggèrent aussi que des pratiques intégrées de gestion de feu et des programmes de restauration écologique peuvent atténuer ces impacts.</p></div>
Impact of Bushfires on Biodiversity and Food Security: Assessment of Ecological, Agronomic, and Socio-Economic Effects
- Dzokom Alexis
Sahel Nature Consulting Revue, Sahel Nature Consulting Revue (March 2025) , 2026, 09 (02), pp.1-14 . <div><p>Bushfires constitute a recurrent phenomenon in many sahelian and savannah regions, profoundly influencing ecosystems and human livelihoods. This study examines the ecological impacts of bushfires on biodiversity (flora and fauna) and their implications for the food security of local populations. By integrating ecological, agronomic, and socio-economic approaches, we assess how burning practices affect species composition, soil productivity, agricultural yields, and community adaptation strategies. The results indicate a significant biodiversity loss of 28%, a reduction in ecosystem resilience of up to 35% one year after seasonal fires, and adverse effects on agricultural production, with an average yield decline of 22% in plots located near burned areas, thereby directly threatening food security. The findings further suggest that integrated fire management practices and ecological restoration programs can mitigate these impacts.</p></div>
Pentanucleotide guanine-rich WGGGW repeats, including CANVAS AGGGA repeats, form a variety of noncanonical structures
- Wang Jiawei
- Qiu Dehui
- Zhou Jun
- Mergny Jean-Louis
- Alberti Patrizia
Nucleic Acids Research, Oxford University Press , 2026, 54 (3) . Abstract Short tandem repeats (STRs) are an important component of the human genome as they contribute to genetic diversity and can influence gene expression and disease susceptibility. STRs are important in the context of CANVAS (Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome) genetic disease as expansions of AGGGA repeats within the RFC1 gene are associated with the development of this neurodegenerative disorder. Interestingly, the RFC1 expanded motifs are pentanucleotides that differ from the nonpathogenic AGAAA pentanucleotide motif present in reference genomes. The molecular mechanisms underlying the pathogenicity of the mutated pentanucleotide expansion in CANVAS are still unknown. Several groups have shown that DNA and RNA containing AGGGA repeats fold into G-quadruplexes (G4s) under physiological K⁺ conditions. In this study, we reveal a more complex than expected behavior, in which DNA WGGGW motifs (where W is A or T) may adopt different G4 and non-G4 structures depending on sequence, repeat number and ionic conditions. These findings are relevant as they may help explain the genomic instability and pathogenicity specifically associated with AGGGA repeats among the WGGGW motifs. (10.1093/nar/gkag051)
DOI : 10.1093/nar/gkag051
Collagen microarchitecture from polarized light imaging: a biomechanics perspective
- Kunz Miriam Bohlmann
- Lee Po-Yi
- Latour Gaël
- Yang Bin
- Schanne-Klein Marie-Claire
- Kurokawa Kazuhiro
- Sigal Ian A
Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers , 2026, 31 (1), pp.010902 . Significance: Collagen, the main load-bearing component in tissue, is present in all animals and forms a variety of networks from the fibrils, fibers, bundles, and lamellae into which it self-assembles. The collagen microstructure is different among tissue types, and the different microstructures give rise to tissue-specific mechanical properties. Therefore, methods for visualizing collagen fibers and their orientation are essential for understanding the biomechanical properties of tissue. Aim: Our aim in this review is to provide the basis for understanding the methodology of polarized light imaging methods and how they can be used to characterize collagen microstructure. Approach: We begin with a description of collagen microstructure and its relationship to tissue biomechanics, a basic formalism of polarized light, and how collagen interacts with polarized light. We then describe polarized light microscopy and its various forms, particularly instant polarized light microscopy, then polarizationsensitive optical coherence tomography, and last, polarization-resolved secondharmonic generation microscopy. Results: We describe methods for imaging collagen microstructure with polarized light from in vivo methods to high-resolution volumetric imaging of tissue sections. Conclusions: We intend to help those interested in using polarized light to image and understand the relationship between collagen microstructure and biomechanics. (10.1117/1.jbo.31.1.010902)
DOI : 10.1117/1.jbo.31.1.010902
Selective Disruption of Plasmodium falciparum mitochondrial DNA via G-Quadruplex-Binding Ligand RHPS4 Provides a Novel Antimalarial Strategy
- Salim Mariam
- Paloque Lucie
- Reyser Thibaud
- Nardella Flore
- Augereau Jean-Michel
- Luo Yu
- Britton Sébastien
- Mergny Jean-Louis
- Gervais Virginie
- Benoit-Vical Françoise
- Gomez Dennis
BioRxiv, BioRxiv , 2026 . ABSTRACT Malaria caused by Plasmodium falciparum remains a major health threat, killing over 600,000 people annually. The spread of resistance to all major antimalarials, including artemisinins, highlights the urgent need for new drugs with distinct mechanisms of action. Here we show that the G-quadruplex ligand RHPS4, an acridine derivative, displays strong antiplasmodial activity against both drug-sensitive and -resistant P. falciparum strains and clinical isolates. RHPS4 primarily targets the trophozoite stage and induces major mitochondrial alterations, including reduction of mitochondrial DNA (mtDNA) and transcriptional dysfunctions. Bioinformatic analyses identified at least eight putative G4-forming sequences within the parasite’s mtDNA. Biophysical studies confirmed G4 folding of at least one sequence and its interaction with RHPS4. These findings indicate that RHPS4 disrupts P. falciparum mitochondrial metabolism through G4 stabilization, leading to parasite death, and establish mtDNA G4 structures as novel therapeutic targets for antimalarial development. (10.64898/2026.01.07.698092)
DOI : 10.64898/2026.01.07.698092
On the origins and variation of nucleotide skews of archaeal genomes
- Paravel Adrien
- Mottez Clémence
- Puech Romain
- Flament Didier
- Becker Hubert F
- Myllykallio Hannu
Frontiers in Microbiology, Frontiers Media , 2026, 17, pp.1727296 . We have used nucleotide skews as the proxy to understand the evolution of archaeal genomes. Our genome-wide studies using substantial datasets suggest that translational selection and the nature of the genetic code are universally conserved determinants of asymmetric guanine and cytosine distributions. We propose that in the case of the majority of bacterial chromosomes, mutational processes and/or DNA repair also result in the strand-specific nucleotide skews. This is in stark contrast to what we observe for archaeal chromosomes and plasmids, and reveals that archaea have a greatly reduced ability to create mutations and/or repair DNA damage in a strand-specific manner. We suggest that in the future, the described computational and statistical approach will help to understand the evolutionary dynamics of the archaeal chromosomes through the tree of life. (10.3389/fmicb.2026.1727296)
DOI : 10.3389/fmicb.2026.1727296
Dynamics and Catalytic Conversion of the CO 2 Coproduct in Fatty Acid Photodecarboxylase
- Bonvalet Adeline
- Balduzzi Elsa
- Légeret Bertrand
- Antonucci Laura
- Samire Poutoum
- Solinas Xavier
- Peltier Gilles
- Beisson Frédéric
- Müller Pavel
- Joffre Manuel
- Hienerwadel Rainer
- Vos Marten
- Berthomieu Catherine
- Aleksandrov Alexey
- Sorigué Damien
ACS Catalysis, American Chemical Society , 2025 . (10.1021/acscatal.5c08787)
DOI : 10.1021/acscatal.5c08787
Corvis <sup>ST</sup> biomechanical indices in the diagnosis of corneal stromal and endothelial disorders: an artificial intelligence-based comparative study
- Borderie Vincent Michel
- Georgeon Cristina
- Louissi Nassim
- Memmi Benjamin
- Hamrani Malika
- Bouheraoua Nacim
- Chessel Anatole
British Journal of Ophthalmology, BMJ Publishing Group , 2025, pp.bjo-2025-327855 . <div>Aims<p>To analyse the value of the Corvis ST indices in diagnosing corneal stromal and endothelial disorders (CSEDs). Methods This institutional retrospective case-control study included 903 eyes with a CSED and 597 normal eyes (controls), assessed with Corvis ST and MS39. Main outcome measures: Corvis ST indices. The collected data were divided into a training set (70%) and a test set (30%). Artificial intelligence frameworks were used to distinguish each disorder from controls and to classify corneas into seven groups: keratoconus, highrisk corneas for keratoconus, laser corneal refractive surgery (LCRS), endothelial disorders, stromal opacities, glaucoma corneas and normal corneas. Results Stress-strain index (SSI) significantly increased with age in the control group. Compared with controls matched for age/sex, keratoconus was associated with Corvis Biomechanical Index (CBI) >0.51 (area under the curve, 0.99), Ambrósio's relational thickness horizontal (ARTh) <425.5 (0.97), deflection amplitude at the time of the first applanation (SPA-A1) <96.3 (0.97) and Pachy<522.4 µm (0.91); high-risk corneas with a difference in CBI between fellow eyes (CBI SYM) >0.14 (0.98), (L2) <1.95 (0.83) and Pachy<549.7 µm (0.71); LCRS with ARTh<455.1 (0.93) and CBI>0.35 (0.83); corneal endothelial disorders with Pachy SYM>19.7 µm (0.83), Pachy>569.1 µm (0.82) and CBI SYM>0.14 (0.77); stromal opacities with SPA-A1 SYM>11.8 (0.92), ARTh<569.9 (0.89), SSI SYM>0.14 (0.89) and CBI>0.22 (0.86). A logistic regression function using all indices reached an area under the receiver operating characteristic curve of 0.81 for glaucoma diagnosis. The TabPFN model provided the best accuracy (88.7%) for diagnosing the seven corneal conditions. SSI, SPA-A1, CBI and Pachy correlated with keratoconus grade. Keratoplasty for keratoconus improved but failed to restore normal corneal biomechanics. Conclusions Corvis ST indices are relevant for diagnosing CESDs and distinguishing various disorders from each other.</p></div> (10.1136/bjo-2025-327855)
DOI : 10.1136/bjo-2025-327855
Deciphering the intermolecular interactions between G-quadruplex (G4)-forming sequences
- Xia Jianjun
- Zhou Jiahang
- Zhuang Xinzhe
- Ju Huangxian
- Monchaud David
- Chaires Jonathan B
- Šponer Jiří
- Mergny Jean-Louis
- Zhou Jun
Nucleic Acids Research, Oxford University Press , 2025, 53 (22) . <div><p>Interactions between biomolecules govern cellular biology. While protein/protein and protein/nucleic acid (DNA, RNA) interactions-and, to a lesser extent, RNA/RNA and RNA/DNA interactions-ha v e been e xtensiv ely described, a question remains as to whether and how non-canonical DNA str uct ures might interact with each other. This is of particular interest for guanine (G)-rich sequences that can fold into G-quadruplex (G4) str uct ures: Individual G4s are currently studied for their involvement in a myriad of cellular events (mostly pertaining to the control of gene expression), and, more recently, the interactions between two G4s have been scrutinized as being part of a novel gene expression regulatory mechanism in v olving chromatin remodeling through G4-mediated loop f ormation. T he question that needs to be answered is whether G4s or their corresponding G-rich sequences are in v olv ed. We present here a series of results collected using a combination of sequences, experimental conditions, and tec hniques, whic h led us to the conclusion that G4/G4 intermolecular interactions are mostly go v erned b y primary sequence interactions in vitro.</p></div> (10.1093/nar/gkaf1288)
DOI : 10.1093/nar/gkaf1288
Label-free nonlinear microscopy probes cellular metabolism and myelin dynamics in live tissue
- Asadipour Bahar
- Morizet Josephine
- Ronzano Remi
- Zhang Xingjian
- Aigrot Marie-Stephane
- Mahou Pierre
- Solinas Xavier
- Phan Minh Son
- Chessel Anatole
- Stankoff Bruno
- Desmazieres Anne
- Beaurepaire Emmanuel
- Stringari Chiara
Communications Biology, Nature Publishing Group , 2025 . Metabolic coupling between neurons and glial cells plays a critical role in brain activity and myelin plasticity. Understanding its role in physiological and pathological contexts requires advanced methods to map metabolism and myelin in live tissue with high spatiotemporal resolution. Here, we present a label-free, multimodal, nonlinear optical microscopy platform integrated with an advanced image processing framework that simultaneously maps cellular metabolism and myelin distribution in organotypic cerebellar cultures. We combine third-harmonic generation microscopy for high-resolution myelin imaging with single axon precision with two-photon fluorescence lifetime microscopy of NAD(P)H metabolic biomarker to assess redox states with single-cell resolution. We introduce automated image analysis methods for cell segmentation and myelinated axon detection, enabling quantitative metabolic and myelin assessment in intact tissue during experimental myelination, demyelination and remyelination. Using this framework, we map the 3D myelin distribution in cerebellar folia and identify distinct metabolic signatures in neurons, oligodendrocytes, and microglia. Furthermore, we measure a metabolic shift in microglia along with myelin distribution changes during experimental demyelination. In conclusion, we establish label-free optical imaging as a powerful tool for the non-invasive characterization of neuro-glial metabolic coupling and myelin organization in living brain tissue, opening new perspectives for research in neuroinflammation and neurodegeneration. (10.1038/s42003-025-09192-4)
DOI : 10.1038/s42003-025-09192-4
Genome-wide ribonucleotide detection in <i>Archaea</i>
- Moalic Yann
- Reveil Maurane
- Kundnani Deepali L
- Balachander Sathya
- Yang Taehwan
- Gombolay Alli
- Ranjbarian Farahnaz
- Brizard Raphael
- Durand Patrick
- Myllykallio Hannu
- Jebbar Mohamed
- Hofer Anders
- Storici Francesca
- Henneke Ghislaine
Nucleic Acids Research, Oxford University Press , 2025, 53 (21) . <div><p>Genome integrity is constantly challenged by the incorporation of ribonucleotides ribonucleoside monophosphates (rNMPs) during DNA synthesis. Co v alently link ed single and se v eral consecutiv e rNMPs occur in the genome of a number of organisms. T he y are mainly introduced by DNA polymerases during DNA replication and repair. In general, cells evolved ribonucleases H (RNases H) specialized in the removal of rN-MPs from DNA to a v oid an y detrimental consequences on genome st abilit y. Here, we describe the in v olv ement of types 1 and/or 2 RNases H in processing embedded rNMPs in the genome of two archaeal species Haloferax volcanii and Thermococcus barophilus . Genome-wide, nucleotide-resolution maps of embedded rNMPs re v eal oriC -centered strand-switching profiles in H. volcanii rnhB , indicating origin firing in native cells, while their absence in T. barophilus reflects low origin usage. The data also define archaeal sequence-context rules for rNMP embedment, confirm the predominant role of RNase HII in rNMP remo v al with e vidence of compensatory repair pathw a y s, and link incorporation patterns to measured rNTP/dNTP pools. Together, these findings unco v er archaeal-specific mechanisms of rNMP incorporation and repair with implications for replication and genome st abilit y.</p></div> (10.1093/nar/gkaf1231)
DOI : 10.1093/nar/gkaf1231
Consensus guidelines for cellular label-free optical metabolic imaging: ensuring accuracy and reproducibility in metabolic profiling
- Georgakoudi Irene
- Skala Melissa
- Quinn Kyle
- Stringari Chiara
- Sorrells Janet
- Heikal Ahmed
- Li Lin
- Xu He
- You Sixian
- Walsh Alex
- Datta Rupsa
- Samimi Kayvan
- Gillette Amani
- Eliceiri Kevin
- Balu Mihaela
- Boppart Stephen
- Digman Michelle
- Dunning Kylie
- Evans Conor
- Garcia Alba Alfonso
- Houston Jessica
- Hwang Wonsang
- Lindley Matthew
- Li Xingde
- Liu Zhiyi
- Marcu Laura
- Murugkar Sangeeta
- Nichols Michael
- Niesner Raluca
- Parekh Sapun
- Rajaram Narasimhan
- Ranjit Suman
- Shen Keyue
- Shi Lingyan
- Torrado Belén
- Vallmitjana Alexander
- Wang-Evers Michael
- Zemp Roger
Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers , 2025, 30 (S2), pp.S23901 . Significance: Cellular metabolism plays a central role in health and disease, making its study critical for advancing diagnostics and therapies. Label-free optical metabolic imaging using endogenous fluorescence from reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] and flavin adenine dinucleotide (FAD) provides nondestructive, high-resolution insights into metabolic function and heterogeneity from the sub-cellular to the tissue level. Standardized approaches are essential to ensure reproducibility and comparability across studies. Aim: We aim to establish a consensus framework for the acquisition, calibration, and reporting of microscopic imaging metabolic function assessments based on fluorescence intensity and lifetime measurements of NAD(P)H and FAD. Approach: We present best practices for calibrating, analyzing, and reporting fluorescence intensity-based optical redox ratios and fluorescence lifetime data using multiexponential fitting and phasor analysis. Guidelines for validation experiments and cross-system standardization are provided to improve accuracy and reproducibility. Results: We demonstrate the importance of calibration procedures and normalization strategies for intensity-based optical redox measurements. We highlight needed calibration, signal-to-noise ratio considerations, and the impact of distinct analytical approaches on fluorescence lifetime-based metabolic function metrics. Conclusion: We recommend a consistent, practical framework for reproducible, label-free, optical metabolic imaging, facilitating robust comparisons across studies and supporting the broader adoption of optical metabolic imaging technologies for biomedical research and clinical translation. (10.1117/1.JBO.30.S2.S23901)
DOI : 10.1117/1.JBO.30.S2.S23901
Designing an ecofriendly catalyst for a sustainable use of water resources
- Qiu Dehui
- Zhang Xiaobo
- Tian Fan
- Liu Yuan
- He Fangni
- Yan Xinrong
- Wei Shijiong
- Mergny Jean-Louis
- Monchaud David
- Zhang Shujuan
- Ju Huangxian
- Zhou Jun
National Science Review, Oxford Academic , 2025, 13 (2), pp.nwaf447 . The printing and dyeing industry is one of the most polluting ( ∼20% of global clean water pollution), water-consuming and energy-wasting sectors in the manufacturing field, highlighting the need to find green catalysts to improve its sustainability. Herein, a novel artificial green catalyst was developed, known as a bifunctional chimeric peptide DNAzyme (bi-CPDzyme), comprising peptide, DNA and hemin moieties. This catalyst displays both catalase (CAT) and peroxidase (POD) activities. The turnover number ( k cat ) of the optimized bi-CPDzyme prototype (G-quadruplex-Hemin-HRRHKHRRH) surpasses the natural CAT/POD bifunctional enzyme KatG, and competes with individual CAT and POD enzymes. This remarkable performance is attributed to the strategic combination and incorporation of histidine (H) and arginine (R) residues, which effectively trap hydrogen peroxide (H 2 O 2 ) near the catalytic center via hydrogen bond formation, thus facilitating the generation of the active intermediate compound I, as supported here by theoretical calculations. Significantly, bi-CPDzyme achieves efficient decomposition of bleaching-derived residual H 2 O 2 in a water-/energy-saving manner, while degrading dyes from textile industry effluents even in complex real samples, in addition to being easily recyclable and implementable. These findings make bi-CPDzyme a cutting-edge and environmentally friendly catalyst, positioning it at the forefront of advancements towards creating a sustainable society. (10.1093/nsr/nwaf447)
DOI : 10.1093/nsr/nwaf447
Ultrafast photooxidation of semireduced flavin in fatty acid photodecarboxylase
- Vos Marten
- Balduzzi Elsa
- Sorigué Damien
- Aleksandrov Alexey
Science Advances, American Association for the Advancement of Science (AAAS) , 2025, 11 (38) . The initial photoproduct of the natural photoenzyme fatty acid photodecarboxylase involves the flavin anion radical flavin adenine dinucleotide (FAD •– ). Using spectrally resolved ultrafast transient absorption spectroscopy, we demonstrate that FAD •– photoexcitation in the absence of substrate leads to the formation of the oxidized flavin FAD ox (the resting state in the catalytic cycle) within 100 femtoseconds. While this feature is similar to that occurring in flavoprotein oxidases, the ensuing photocycle is more complex. Upon excitation at the lowest-energy transition, the ejected electron is initially captured as a hydrated electron ( e – H ) before transferring to a secondary acceptor in 2.5 picoseconds and returning to the flavin in 37 picoseconds. This implies that e – H can be generated within a protein environment, an unprecedented finding. This assessment is supported by molecular dynamics simulations showing an expansion of the flavin-binding pocket without substrate, allowing water molecules to fill the void. Our results may pave the way to developing unconventional photocatalytic processes. (10.1126/sciadv.adz1904)
DOI : 10.1126/sciadv.adz1904
A Selective and Sensitive Method for Colistin Detection by G-Quadruplex Ligand Competition
- Wei Shijiong
- Qiu Dehui
- Yan Xinrong
- Liu Bin
- Mergny Jean-Louis
- Monchaud David
- Ju Huangxian
- Zhou Jun
Analytical Chemistry, American Chemical Society , 2025, 97 (31), pp.16805 . Colistin (COL) is a widely used antibiotic and is quite often used as a last-resort treatment option for treating multidrug-resistant Gram-negative bacterial infections. Due to its widespread use, COL accumulates in nature, which represents a novel ecological and health threat. However, there is currently no rapid and specific method available for titrating COL levels in collected samples. Herein, we report a simple chemiluminescence detection method based on the specific interaction between COL and a parallel G-quadruplex (G4). To this end, we exploit the catalytic properties of the G4/hemin DNAzyme, which is able to oxidize substrates to provide a readily monitored readout. The stronger affinity of G4 for COL versus hemin allows for the inactivation of the G4/hemin DNAzyme, which is used herein to quantify COL in solution. Through a series of optimizations, we identified the best G4 sequence (F3TC), oxidation substrate (luminol), and experimental conditions, which allow for the detection of COL over a broad concentration window, from 0.5 to 2,500 ng/mL, with a detection limit of 0.4 ng/mL and excellent selectivity against other antibiotics. Compared with existing methods, the proposed approach provides a simpler and label-free quantification of COL, which might serve as a valuable standard method for antibiotic detection, whose use was validated under real conditions herein (10.1021/acs.analchem.5c01733)
DOI : 10.1021/acs.analchem.5c01733
Design, synthesis, biophysical and biological evaluation of original condensed pyrrolopyrimidine and pyrrolopyridine ligands as anti-SARS-CoV-2 agents targeting G4
- Guillon Jean
- Savrimoutou Solène
- da Rocha Nicolas
- Albenque-Rubio Sandra
- Helynck Olivier
- Durand Cyrielle
- Chiaravalli Jeanne
- Pinaud Noël
- Ronga Luisa
- Moreau Stéphane
- Chirold Simon
- Zangmo Tshering
- Arab Melika
- Lari Lindita
- Mergny Jean‐louis
- Munier-Lehmann Hélène
- Lavigne Marc
European Journal of Medicinal Chemistry, Elsevier , 2025, 292, pp.117655 . The design and synthesis of novel bis[(substituted-aminomethyl)phenyl]phenyl pyrrolopyrimidines, pyrrolopyridines, pyrazolopyrimidines, imidazopyrimidines, and tris[(substituted-aminomethyl)phenyl]phenyl pyrrolopyrimidines are reported here. These original G-quadruplex (G4) ligands have been then subjected to a screening on SARS-CoV-2 using a competition HTRF assay by targeting the SUD-NM/TRF2 RNA G4 interaction. The more promising derivatives have been evaluated in vitro to determine their potential antiviral effect on two different cell lines infected by two SARS-CoV-2 strains. This study revealed a clear correlation between their antiviral property and their efficacy to prevent the SUD/G4 interaction. This correlation supports the choice of SUD/RNA G4 complexes formed during SARS-CoV-2 infection as new antiviral targets (10.1016/j.ejmech.2025.117655)
DOI : 10.1016/j.ejmech.2025.117655
Chromium‐Doped Zinc Gallate Nanoparticles for Enhanced Enzyme‐Linked Immunosorbent Assay Sensitivity: Optimization of Synthesis and Functionalization Strategies for Ultra‐Low IgG Detection
- Ferjaoui Zied
- Liu Jianhua
- Matuszewska Celina
- Chanéac Corinne
- Viana Bruno
- Bouzigues Cédric
- Scherman Daniel
- Mignet Nathalie
- Richard Cyrille
Small Science, Wiley , 2025, 5 (10) . The use of zinc gallate nanoparticles (ZnGa 2 O 4 :Cr 3+ ) (ZGO‐NPs) presents significant potential for improving the sensitivity in enzyme‐linked immunosorbent assays (ELISA). The persistent luminescence signal increase of these nanoparticles in the presence of hydrogen peroxide (H 2 O 2 ) offers advantages for the sensitive detection of biomolecules. Herein, different conditions of ZGO synthesis have been investigated by varying the hydrothermal reaction duration (6, 12, and 24 h) and examining its impact in the presence of H 2 O 2 . These nanoparticles have been integrated into ELISA assays, using as target antigen IgG. The lowest limit of detection (LOD) of 0.2 pg mL −1 is observed for ZGO‐NPs prepared during 12 h (ZGO2), and with a detection range from 1 to 1000 pg mL −1 . The impact of covalently functionalizing these nanoparticles has then been assessed. First using glucose oxidase (GOx) and the detection antibody (Ab D ) linked to PEGylated ZGO‐NPs, named ZGO‐GOx‐Ab D . Alternatively, only the detection antibody is linked to the PEG ZGO‐NPs, named ZGO‐Ab D . The results show a significant lowering of the LOD when using the functionalized ZGO2 NPs and also highlight the impact of the signal amplification by H 2 O 2 . Specifically, when using ZGO2‐GOx‐Ab D incubated with glucose to produce H 2 O 2 , or with ZGO2‐Ab D to which H 2 O 2 was added, the LODs are ≈98 and 56 fg mL −1 respectively, with detection ranges from 0.01 to 100 pg mL −1 . (10.1002/smsc.202500177)
DOI : 10.1002/smsc.202500177
Machine Learning Model for Predicting Visual Acuity Improvement After Intrastromal Corneal Ring Surgery in Patients With Keratoconus
- Perez Eva
- Louissi Nassim
- Kallel Sofiene
- Hays Quentin
- Bouheraoua Nacim
- Hamrani Malika
- Chessel Anatole
- Borderie Vincent
Cornea, Lippincott, Williams & Wilkins , 2025 . Background: Keratoconus is a progressive, degenerative corneal disease that can lead to significant visual impairment. The intrastromal ring segment implantation procedure is effective in reshaping the cornea and improving vision. However, vision does not improve postoperatively in all operated eyes, and the results vary widely among patients, making it challenging to predict postoperative visual gain. Purpose: This study investigated the potential of machine learning in predicting postoperative visual acuity in keratoconus patients undergoing intrastromal ring segment implantation with the aim of enhancing surgical decision-making. Methods: This retrospective study analyzed 120 eyes of 102 patients with keratoconus who underwent ring segment implantation (1 symmetric or asymmetric segment, 150-300 mm thick, 150 degrees, or 160 degrees-arc). Preoperative and postoperative refraction, corneal topography, and tomographic data were collected. Various models were trained to predict postoperative visual acuity improvements. Results: The models demonstrated excellent performance, with XGBoost achieving perfect results in predicting whether vision will improve after surgery (R 2 = 1.0, Youden Index = 1.0; all test observations being correctly classified). The CatBoost model achieved an R 2 of 0.59 [0.7-line mean absolute error (MAE)] for predicting postoperative visual acuity, an R 2 of 0.76 (MAE, 1.08 D) for predicting keratometry, and an R 2 of 0.54 (MAE, 0.29) for predicting corneal asphericity. Key features for accurate predictions included preoperative keratometry values (K1, K2, Kmax), corneal asphericity, and visual acuity, whereas segment characteristics featured low importance. Conclusions: This study shows the strong potential of machine learning for selecting candidates for surgery and predicting postoperative visual improvements after ring segment implantation in keratoconus eyes. (10.1097/ICO.0000000000003933)
DOI : 10.1097/ICO.0000000000003933
In situ determination and matching of the refractive index of the Human cornea to improve polarization-resolved SHG imaging in depth
- Nyembo Kasongo Poncia
- Mahou Pierre
- Sintès Jean-Marc
- Latour Gaël
- Schanne-Klein Marie-Claire
Biomedical optics express, Optical Society of America - OSA Publishing , 2025, 16 (8), pp.3270-3282 . <div><p>The human cornea is a highly organized tissue, which comprises hundreds of 1-3 µm thick stacked collagen lamellae. However, this microstructure is poorly characterized and requires further investigation. Polarization-resolved second harmonic generation (pSHG) microscopy is a powerful technique for this purpose because of its specificity for collagen and its sensitivity to its orientation. However, pSHG is prone to spatial resolution degradation with depth unless the immersion refractive index is matched to that of the sample, which is critical for corneas that are approximately 600 µm thick. In the absence of experimental data on the refractive index along the entire cornea, we propose a measurement method that applies to the entire cornea directly under the microscope objective. We then use an iodixanol solution to match the refractive index of the immersion medium to that of the cornea. Finally, we carefully characterize the pSHG orientation data obtained under these optimal conditions, and we show that they provide a better resolution along the entire thickness of the cornea and a better determination of the lamellae orientation.</p></div> (10.1364/boe.564209)
DOI : 10.1364/boe.564209
Multiscale characterization of myelin distribution with polarized THG microscopy
- Morizet Josephine
- Olivier Nicolas
- Aigrot Marie-Stephane
- Mahou Pierre
- Martin Elodie
- Desmazieres Anne
- Stankoff Bruno
- Stringari Chiara
- Beaurepaire Emmanuel
Optica, Optical Society of America - OSA Publishing , 2025, 12 (7), pp.1122 . Myelin is essential for axonal conduction and metabolic support. To better understand its role in health and disease, it is necessary to establish accurate methods for in situ mapping of myelin at scales ranging from submicrometer to centimeters. Third-harmonic generation (THG) microscopy has recently been proposed as an efficient label-free method to visualize myelin in thick and living tissue. However, the contrast mechanism of THG from myelinated axons is complex and poorly described, which has limited the development of THG as a quantitative probe of myelin distribution. Here, we present a systematic characterization and modeling of polarization-resolved THG (pTHG) signals from individual axons as a function of their diameter and myelin thickness, and we show that pTHG can be used to derive myelin scores in several biological systems. First, we confirm the sensitivity and specificity of the THG contrast for myelinated axons in mouse brain tissue and its ability to detect isolated micrometer-sized axons oriented both in-plane and out-of-plane. We then present a detailed characterization of the pTHG contrast of small and large axons in live zebrafish larvae at different developmental stages, and we demonstrate that pTHG detects early axon development in vivo. We show that classical models of coherent multiphoton microscopy fail to reproduce pTHG profiles of axons because they neglect myelin-induced optical aberrations, and we establish a numerical strategy based on finite-difference time-domain calculations that can accurately relate pTHG signal profiles to axonal diameter and myelin thickness. Finally, we illustrate the relevance of pTHG microscopy for characterizing myelin distribution at different scales in fixed mouse and human brain tissue. (10.1364/optica.562091)
DOI : 10.1364/optica.562091
Editorial: The metabolic pathways of archaea
- Myllykallio Hannu
- Qin Wei
- Berg Ivan
Frontiers in Microbiology, Frontiers Media , 2025, 16 . (10.3389/fmicb.2025.1648560)
DOI : 10.3389/fmicb.2025.1648560
Time Delay Distribution and Laser Stability in Arbitrary Detuning Asynchronous Optical Sampling
- Antonucci Laura
- Bonvalet A.
- Solinas X.
- Joffre M.
Journal of Physical Chemistry A, American Chemical Society , 2025, 129 (27), pp.6121-6132 . Arbitrary Detuning ASynchronous OPtical Sampling (ADA-SOPS) is an emerging technique for extending standard pump−probe experiments performed with two femtosecond lasers to multitimescale experiments, which are of great interest for the study of complex systems. Although no specific requirements are needed for laser repetition rates, their ratio determines the achievable delay distribution and therefore is strongly related to the temporal resolution of the technique. We report a detailed theoretical analysis of measurement performances with respect to laser repetition rates, and we validate our model with experimental data. In the case of amplified laser systems, we demonstrate that achieved delays are inherently correlated to the time interval between amplified pulses, which affects the pulse energy and can generate artifacts. Nevertheless, a deep understanding of the origin of such artifacts allows to suggest several compensation strategies, either during data analysis or at the conception of the experimental setup. Finally we present a new algorithm integrated into the ADASOPS device: by selecting pairs of probe pulses having the same elapsed time with respect to the previous pulse, it automatically compensates any effect of energy fluctuation. (10.1021/acs.jpca.5c01853)
DOI : 10.1021/acs.jpca.5c01853
IgG detection in human serum employing non-functionalized chromium doped zinc gallate nanoparticles
- Ferjaoui Zied
- Zimmer Capucine
- Matuszewska Celina
- Chanéac Corinne
- Viana Bruno
- Bouzigues Cédric
- Scherman Daniel
- Mignet Nathalie
- Richard Cyrille
Next Nanotechnology, Elsevier , 2025, 8, pp.100199 . Chromium-doped zinc gallate (ZnGa2O4:Cr3 +) nanoparticles (ZGO) show promising potential for antigen immunodetection using persistent luminescence, thereby reducing autofluorescence interference. Recently, we have shown that ZGO prepared by hydrothermal treatment at 120°C for 24 h can be used for in vitro biodetection in simple media such as phosphate-buffered saline. In this study, we investigated the effect of the protocol used to synthesize these ZGO nanoparticles, using a hydrothermal treatment at 220°C for different durations (6 h, 12 h, and 24 h), followed by calcination at 500°C. The nanoparticle size determined by transmission electron microscopy after grinding and centrifugation was found to be around 15 nm. The persistent luminescence signal of the ZGO nanoparticles varied with the hydrothermal synthesis conditions. Moreover, in the presence of H2O2, these nanoparticles show a signal enhancement dependent on the hydrothermal duration, with a 12 h treatment showing the highest 8-fold luminescence increase in the presence of H2O2 produced by glucose oxidase mediated glucose degradation. Based on these results, these non-functionalized nanoparticles were successfully used to develop a persistent luminescence-based sandwich immunoassay for autofluorescence-free detection of antigens in undiluted human serum samples, using rabbit IgG as a model antigen. This study highlights the promising potential for biosensing applications of persistent ZGO nanophosphors for IgG detection in a complex medium (undiluted human serum), with a linear range from 1 ng mL−1 to 104 ng mL−1 and a limit of detection of 0.01 ng mL−1. The present optimization of ZGO nanophosphor synthesis offers promising prospects for medical diagnostics due to their increased sensitivity and ability to eliminate autofluorescence interference, as well as their ease of use, since no functionalization of the ZGO NPs is required before use. (10.1016/j.nxnano.2025.100199)
DOI : 10.1016/j.nxnano.2025.100199
Laser driven FLASH radiobiology using a high dose and ultra high dose rate single pulse proton source
- Flacco A
- Bayart E.
- Romagnani L
- Cavallone M.
- de Marzi L.
- Fouillade C
- Giaccaglia C.
- Heinrich S.
- Lamarre-Jouenne I.
- Monzac J.
- Parodi K.
- Patriarca A
- Rösch T
- Schreiber J
- Tischendorf L
Scientific Reports, Nature Publishing Group , 2025, 15, pp.16511 . Laser-driven proton sources have long been developed with an eye on their potential for medical application to radiation therapy. These sources are compact, versatile, and show peculiar characteristics such as extreme instantaneous dose rates, short duration and broad energy spectrum. Typical temporal modality of laser-driven irradiation, the so-called fast-fractionation, results from the composition of multiple, temporally separated, ultra-short dose fractions. In this paper we present the use of a high-energy laser system for delivering the target dose in a single nanosecond pulse, for ultra-fast irradiation of biological samples. A transport line composed by two permanent-magnet quadrupoles and a scattering system is used to improve the dose profile and to control the delivered dose-per-pulse. A single-shot dosimetry protocol for the broad-spectrum proton source using Monte Carlo simulations was developed. Doses as high as 20 Gy could be delivered in a single shot, lasting less than 10 ns over a 1 cm diameter biological sample, at a dose-rate exceeding 10 9 Gy s -1 . Exploratory application of extreme laser-driven irradiation conditions, falling within the FLASH irradiation protocol, are presented for irradiation in vitro and in vivo. A reduction of radiation-induced oxidative stress in vitro and radiation-induced developmental damage compatible with the onset of FLASH effect were observed in vivo, whereas anti-tumoral efficacy was confirmed by cell survival assay. (10.1038/s41598-025-01105-z)
DOI : 10.1038/s41598-025-01105-z
Two-dimensional infrared spectroscopy using a fast-scanning interferometer and chirped pulse up-conversion at 100 kHz
- Jonušas Mindaugas
- Bournet Quentin
- Bonvalet Adeline
- Natile Michele
- Ersen Andrei-Ovidiu
- Guichard Florent
- Zaouter Yoann
- Georges Patrick
- Druon Frédéric
- Hanna Marc
- Joffre Manuel
The Journal of Chemical Physics, American Institute of Physics , 2025, 162 (17), pp.174201 . We report on a 100-kHz two-dimensional infrared (2DIR) spectrometer in the pump-probe geometry, which we apply to the measurement of the 2DIR spectrum of carboxy-hemoglobin. The probe pulses are spectrally resolved by chirped-pulse upconversion (CPU) using a fast 2048-pixel linescan CMOS camera. The two-pulse pump sequence is generated using a conventional interferometer with a fast-scanning mechanical delay line allowing to achieve a scanning frequency of 2 Hz. The resulting modulation frequency of 3.1 kHz is large enough to shift the relevant signal away from the low-frequency noise of the laser source. The combined use of an interferometer on the pump side and of CPU on the probe side opens the way to an improved spectral resolution in both pump and probe dimensions, as compared to currently-available 100-kHz 2DIR spectrometers based on pulse shapers and Mercury-Cadmium Telluride (MCT) detector arrays. (10.1063/5.0261494)
DOI : 10.1063/5.0261494