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Bugallo A, Sánchez M, Fernández-García M, Segurado M. S-phase checkpoint prevents leading strand degradation from strand-associated nicks at stalled replication forks. Nucleic Acids Res 2024:gkae192. [PMID: 38520409 DOI: 10.1093/nar/gkae192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 03/25/2024] Open
Abstract
The S-phase checkpoint is involved in coupling DNA unwinding with nascent strand synthesis and is critical to maintain replication fork stability in conditions of replicative stress. However, its role in the specific regulation of leading and lagging strands at stalled forks is unclear. By conditionally depleting RNaseH2 and analyzing polymerase usage genome-wide, we examine the enzymology of DNA replication during a single S-phase in the presence of replicative stress and show that there is a differential regulation of lagging and leading strands. In checkpoint proficient cells, lagging strand replication is down-regulated through an Elg1-dependent mechanism. Nevertheless, when checkpoint function is impaired we observe a defect specifically at the leading strand, which was partially dependent on Exo1 activity. Further, our genome-wide mapping of DNA single-strand breaks reveals that strand discontinuities highly accumulate at the leading strand in HU-treated cells, whose dynamics are affected by checkpoint function and Exo1 activity. Our data reveal an unexpected role of Exo1 at the leading strand and support a model of fork stabilization through prevention of unrestrained Exo1-dependent resection of leading strand-associated nicks after fork stalling.
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Affiliation(s)
- Alberto Bugallo
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Mar Sánchez
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - María Fernández-García
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Mónica Segurado
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
- Departamento de Microbiología y Genética (USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
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Luttmann M, Vimal M, Guer M, Hergott JF, Khoury AZ, Hernández-García C, Pisanty E, Ruchon T. Nonlinear up-conversion of a polarization Möbius strip with half-integer optical angular momentum. Sci Adv 2023; 9:eadf3486. [PMID: 36961899 PMCID: PMC10038335 DOI: 10.1126/sciadv.adf3486] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Symmetries and conservation laws of energy, linear momentum, and angular momentum play a central role in nonlinear optics. Recently, paraxial light fields with nontrivial topology have been attracting a keen interest. Despite not being eigenstates of the orbital and spin angular momenta (OAM and SAM), they are eigenstates of the generalized angular momentum (GAM) operator-a mixture of the OAM and SAM operators with fractional eigenvalues. By driving high harmonic generation with a polarization Möbius strip carrying a half-integer GAM charge and implementing angular momentum characterization methods in the extreme ultraviolet range, we demonstrate the linear scaling of the GAM with the harmonic order, each harmonic carrying a precise half-integer GAM charge. Our work shows that beyond SAM and OAM, the GAM is, in some situations, an appropriate quantum number. It paves the way for finer manipulations and applications of light beams containing fractional-order polarization singularities.
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Affiliation(s)
- Martin Luttmann
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
| | - Mekha Vimal
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
| | - Matthieu Guer
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
- Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008, Spain
| | | | - Antonio Z. Khoury
- Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24210-346, Brazil
| | - Carlos Hernández-García
- Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008, Spain
| | - Emilio Pisanty
- Department of Physics, King’s College London, Strand Campus, London WC2R 2LS, UK
| | - Thierry Ruchon
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
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Grau-Pujol B, Martí-Soler H, Escola V, Demontis M, Jamine JC, Gandasegui J, Muchisse O, Cambra-Pellejà M, Cossa A, Martinez-Valladares M, Sacoor C, Van Lieshout L, Cano J, Giorgi E, Muñoz J. Towards soil-transmitted helminths transmission interruption: The impact of diagnostic tools on infection prediction in a low intensity setting in Southern Mozambique. PLoS Negl Trop Dis 2021; 15:e0009803. [PMID: 34695108 PMCID: PMC8568186 DOI: 10.1371/journal.pntd.0009803] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 11/04/2021] [Accepted: 09/09/2021] [Indexed: 11/19/2022] Open
Abstract
World Health Organization goals against soil-transmitted helminthiases (STH) are pointing towards seeking their elimination as a public health problem: reducing to less than 2% the proportion of moderate and heavy infections. Some regions are reaching WHO goals, but transmission could rebound if strategies are discontinued without an epidemiological evaluation. For that, sensitive diagnostic methods to detect low intensity infections and localization of ongoing transmission are crucial. In this work, we estimated and compared the STH infection as obtained by different diagnostic methods in a low intensity setting. We conducted a cross-sectional study enrolling 792 participants from a district in Mozambique. Two stool samples from two consecutive days were collected from each participant. Samples were analysed by Telemann, Kato-Katz and qPCR for STH detection. We evaluated diagnostic sensitivity using a composite reference standard. By geostatistical methods, we estimated neighbourhood prevalence of at least one STH infection for each diagnostic method. We used environmental, demographical and socioeconomical indicators to account for any existing spatial heterogeneity in infection. qPCR was the most sensitive technique compared to composite reference standard: 92% (CI: 83%- 97%) for A. lumbricoides, 95% (CI: 88%- 98%) for T. trichiura and 95% (CI: 91%- 97%) for hookworm. qPCR also estimated the highest neighbourhood prevalences for at least one STH infection in a low intensity setting. While 10% of the neighbourhoods showed a prevalence above 20% when estimating with single Kato-Katz from one stool and Telemann from one stool, 86% of the neighbourhoods had a prevalence above 20% when estimating with qPCR. In low intensity settings, STH estimated prevalence of infection may be underestimated if based on Kato-Katz. qPCR diagnosis outperformed the microscopy methods. Thus, implementation of qPCR based predictive maps at STH control and elimination programmes would disclose hidden transmission and facilitate targeted interventions for transmission interruption.
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Affiliation(s)
- Berta Grau-Pujol
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic—University of Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Mundo Sano Foundation, Buenos Aires, Argentina
- * E-mail:
| | - Helena Martí-Soler
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic—University of Barcelona, Barcelona, Spain
| | - Valdemiro Escola
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Maria Demontis
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | | | - Javier Gandasegui
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, León, Spain
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana, León, Spain
| | - Osvaldo Muchisse
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Maria Cambra-Pellejà
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, León, Spain
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana, León, Spain
| | - Anelsio Cossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Maria Martinez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, León, Spain
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana, León, Spain
| | - Charfudin Sacoor
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Lisette Van Lieshout
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Jorge Cano
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, The Republic of the Congo
| | - Emanuele Giorgi
- Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Faculty of Health and Medicine, Lancaster University, United Kingdom
| | - Jose Muñoz
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic—University of Barcelona, Barcelona, Spain
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