The Yin-Yang of the Green Fluorescent Protein:Impact on Saccharomyces cerevisiae stress resistance

International audienceAlthough fluorescent proteins are widely used as biomarkers (Yin), no study focuses on their influence on the microbial stress response. Here, the Green Fluorescent Protein (GFP) was fused to two proteins of interest in Saccharomyces cerevisiae. Pab1p and Sur7p, respectively involved in stress granules structure and in Can1 membrane domains. These were chosen since questions remain regarding the understanding of the behavior of S. cerevisiae facing different heat kinetics or oxidative stresses. The main results showed that Pab1p-GFP fluorescent mutant displayed a higher resistance than that of the wild type under a heat shock. Moreover, fluorescent mutants exposed to oxidative stresses displayed changes in the cultivability compared to the wild type strain. In silico approaches showed that the presence of the GFP did not influence the structure and so the functionality of the tagged proteins meaning that changes in yeast resistance were certainly related to GFP ROS-scavenging ability (Yang)

Marine organic matter in the remote environment of the Cape Verde islands-an introduction and overview to the MarParCloud campaign

The project MarParCloud (Marine biological production, organic aerosol Particles and marine Clouds: a process chain) aims to improve our understanding of the genesis, modification and impact of marine organic matter (OM) from its biological production, to its export to marine aerosol particles and, finally, to its ability to act as ice-nucleating particles (INPs) and cloud condensation nuclei (CCN). A field campaign at the Cape Verde Atmospheric Observatory (CVAO) in the tropics in September-October 2017 formed the core of this project that was jointly performed with the project MARSU (MARine atmospheric Science Unravelled). A suite of chemical, physical, biological and meteorological techniques was applied, and comprehensive measurements of bulk water, the sea surface microlayer (SML), cloud water and ambient aerosol particles collected at a ground-based and a mountain station took place. Key variables comprised the chemical characterization of the atmospherically relevant OM components in the ocean and the atmosphere as well as measurements of INPs and CCN. Moreover, bacterial cell counts, mercury species and trace gases were analyzed. To interpret the results, the measurements were accompanied by various auxiliary parameters such as air mass back-trajectory analysis, vertical atmospheric profile analysis, cloud observations and pigment measurements in seawater. Additional modeling studies supported the experimental analysis. During the campaign, the CVAO exhibited marine air masses with low and partly moderate dust influences. The marine boundary layer was well mixed as indicated by an almost uniform particle number size distribution within the boundary layer. Lipid biomarkers were present in the aerosol particles in typical concentrations of marine background conditions. Accumulation-and coarse-mode particles served as CCN and were efficiently transferred to the cloud water. The ascent of ocean-derived compounds, such as sea salt and sugar-like compounds, to the cloud level, as derived from chemical analysis and atmospheric transfer modeling results, denotes an influence of marine emissions on cloud formation. Organic nitrogen compounds (free amino acids) were enriched by several orders of magnitude in submicron aerosol particles and in cloud water compared to seawater. However, INP measurements also indicated a significant contribution of other non-marine sources to the local INP concentration, as (biologically active) INPs were mainly present in supermicron aerosol particles that are not suggested to undergo strong enrichment during ocean-atmosphere transfer. In addition, the number of CCN at the supersaturation of 0.30 % was about 2.5 times higher during dust periods compared to marine periods. Lipids, sugar-like compounds, UV-absorbing (UV: ultraviolet) humic-like substances and low-molecularweight neutral components were important organic compounds in the seawater, and highly surface-active lipids were enriched within the SML. The selective enrichment of specific organic compounds in the SML needs to be studied in further detail and implemented in an OM source function for emission modeling to better understand transfer patterns, the mechanisms of marine OM transformation in the atmosphere and the role of additional sources. In summary, when looking at particulate mass, we see oceanic compounds transferred to the atmospheric aerosol and to the cloud level, while from a perspective of particle number concentrations, sea spray aerosol (i.e., primary marine aerosol) contributions to both CCN and INPs are rather limited. © Author(s) 2020

Marine organic matter in the remote environment of the Cape Verde islands – an introduction and overview to the MarParCloud campaign

The project MarParCloud (Marine biological production, organic aerosol Particles and marine Clouds: a process chain) aims to improve our understanding of the genesis, modification and impact of marine organic matter (OM) from its biological production, to its export to marine aerosol particles and, finally, to its ability to act as ice-nucleating particles (INPs) and cloud condensation nuclei (CCN). A field campaign at the Cape Verde Atmospheric Observatory (CVAO) in the tropics in September–October 2017 formed the core of this project that was jointly performed with the project MARSU (MARine atmospheric Science Unravelled). A suite of chemical, physical, biological and meteorological techniques was applied, and comprehensive measurements of bulk water, the sea surface microlayer (SML), cloud water and ambient aerosol particles collected at a ground-based and a mountain station took place. Key variables comprised the chemical characterization of the atmospherically relevant OM components in the ocean and the atmosphere as well as measurements of INPs and CCN. Moreover, bacterial cell counts, mercury species and trace gases were analyzed. To interpret the results, the measurements were accompanied by various auxiliary parameters such as air mass back-trajectory analysis, vertical atmospheric profile analysis, cloud observations and pigment measurements in seawater. Additional modeling studies supported the experimental analysis. During the campaign, the CVAO exhibited marine air masses with low and partly moderate dust influences. The marine boundary layer was well mixed as indicated by an almost uniform particle number size distribution within the boundary layer. Lipid biomarkers were present in the aerosol particles in typical concentrations of marine background conditions. Accumulation- and coarse-mode particles served as CCN and were efficiently transferred to the cloud water. The ascent of ocean-derived compounds, such as sea salt and sugar-like compounds, to the cloud level, as derived from chemical analysis and atmospheric transfer modeling results, denotes an influence of marine emissions on cloud formation. Organic nitrogen compounds (free amino acids) were enriched by several orders of magnitude in submicron aerosol particles and in cloud water compared to seawater. However, INP measurements also indicated a significant contribution of other non-marine sources to the local INP concentration, as (biologically active) INPs were mainly present in supermicron aerosol particles that are not suggested to undergo strong enrichment during ocean–atmosphere transfer. In addition, the number of CCN at the supersaturation of 0.30 % was about 2.5 times higher during dust periods compared to marine periods. Lipids, sugar-like compounds, UV-absorbing (UV: ultraviolet) humic-like substances and low-molecular-weight neutral components were important organic compounds in the seawater, and highly surface-active lipids were enriched within the SML. The selective enrichment of specific organic compounds in the SML needs to be studied in further detail and implemented in an OM source function for emission modeling to better understand transfer patterns, the mechanisms of marine OM transformation in the atmosphere and the role of additional sources. In summary, when looking at particulate mass, we see oceanic compounds transferred to the atmospheric aerosol and to the cloud level, while from a perspective of particle number concentrations, sea spray aerosol (i.e., primary marine aerosol) contributions to both CCN and INPs are rather limited

Le théâtre de Johannes Harmonius Marsus : étude dramaturgique et traduction

Johannes Harmonius Marsus (Giovanni Armonio Marso), poéte humaniste vénitien de la fin du Quatrrocento, a composé en latin, entre autres, deux pièces de théâtre : une comédie intitulée Stephanium, très proche de la fabula palliata romaine, et une tragédie historique, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, pour célébrer l'entrée triomphale du roi français à Milan en 1499. Alors que la comédie a connu un succès retentissant dès sa première représentation et que, à l'inverse, la tragédie est restée complètement méconnue, il a paru important d'approfondir les caractéristiques dramaturgiques de ces deux pièces définies par la recherche constante de l'effet spectaculaire au service d'une intention édifiante. Notre traduction des deux pièces, la première en français, a ainsi été réalisée avec le souci de mettre en valeur le jeu scénique à travers lequel se dessine une nouvelle approche de la comédie et de la tragédie. L'étude du contexte d'écriture et la recherche des sources et modèles littéraires antiques (principalement Plaute et Térence d'une part, Sénèque et Claudien d'autre part) ont été réalisées dans le prolongement des travaux pionniers de Gilbert Tournoy (1978) pour la tragédie et de Ludwig Walther (1971) et Graziella Gentilini (1983) pour la comédie ; ainsi, par l'étude des similitudes et différences entre ces deux œuvres, nous avons essayé de définir l'originalité de l'esthétique dramatique de l'auteur ainsi que la place respective de chacune des deux pièces dans l'histoire de la réception des modèles poétiques de l'Antiquité et de l'élaboration, sans cesse renouvelée, du théâtre latin humanisteJohannes Harmonius Marsus (Giovanni Armonio Marso), a Venetian humanist poet ofthe end of the Quattrocento, composed in Latin, among others, two plays : a comedy entitled Stephanium, very similar to the Roman fabula palliata, and a historical tragedy, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, in order to celebrate the triumphant entrance of the French king in Milan in 1499. As the comedy had a resounding success from its first performance, and the tragedy, on the contrary, has remained completely neglected, it seemed important to deepen the dramaturgical characteristics of these two plays which are defined by the constant pursuit of the spectacular effect, thus serving the intention of edifying and praising. Then in our translation of both plays, the first time in French, we were careful to emphasize the stage acting through which a new approach of comedy and tragedy is taking shape. The study of the context of writing and the search for the ancient literary sources and models (mainly Plautus and Terence on the one hand, Seneca and Claudian on the other hand) have been carried out following the pioneer works of Gilbert Tournoy (1978) concerning the tragedy, of Ludwig Walther (1971) and Grazielle Gentilini (1983) concerning the comedy. Thus, by studying the similarities and the differences between these two works, we tried to define the originality of the author's dramatic aesthetic, as well as the respective places of each of both plays in the history of the reception of antiquity's poetic models, and of the constantly renewed development of the Latin humanist theatre

Le théâtre de Johannes Harmonius Marsus : étude dramaturgique et traduction

Johannes Harmonius Marsus (Giovanni Armonio Marso), poéte humaniste vénitien de la fin du Quatrrocento, a composé en latin, entre autres, deux pièces de théâtre : une comédie intitulée Stephanium, très proche de la fabula palliata romaine, et une tragédie historique, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, pour célébrer l'entrée triomphale du roi français à Milan en 1499. Alors que la comédie a connu un succès retentissant dès sa première représentation et que, à l'inverse, la tragédie est restée complètement méconnue, il a paru important d'approfondir les caractéristiques dramaturgiques de ces deux pièces définies par la recherche constante de l'effet spectaculaire au service d'une intention édifiante. Notre traduction des deux pièces, la première en français, a ainsi été réalisée avec le souci de mettre en valeur le jeu scénique à travers lequel se dessine une nouvelle approche de la comédie et de la tragédie. L'étude du contexte d'écriture et la recherche des sources et modèles littéraires antiques (principalement Plaute et Térence d'une part, Sénèque et Claudien d'autre part) ont été réalisées dans le prolongement des travaux pionniers de Gilbert Tournoy (1978) pour la tragédie et de Ludwig Walther (1971) et Graziella Gentilini (1983) pour la comédie ; ainsi, par l'étude des similitudes et différences entre ces deux œuvres, nous avons essayé de définir l'originalité de l'esthétique dramatique de l'auteur ainsi que la place respective de chacune des deux pièces dans l'histoire de la réception des modèles poétiques de l'Antiquité et de l'élaboration, sans cesse renouvelée, du théâtre latin humanisteJohannes Harmonius Marsus (Giovanni Armonio Marso), a Venetian humanist poet ofthe end of the Quattrocento, composed in Latin, among others, two plays : a comedy entitled Stephanium, very similar to the Roman fabula palliata, and a historical tragedy, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, in order to celebrate the triumphant entrance of the French king in Milan in 1499. As the comedy had a resounding success from its first performance, and the tragedy, on the contrary, has remained completely neglected, it seemed important to deepen the dramaturgical characteristics of these two plays which are defined by the constant pursuit of the spectacular effect, thus serving the intention of edifying and praising. Then in our translation of both plays, the first time in French, we were careful to emphasize the stage acting through which a new approach of comedy and tragedy is taking shape. The study of the context of writing and the search for the ancient literary sources and models (mainly Plautus and Terence on the one hand, Seneca and Claudian on the other hand) have been carried out following the pioneer works of Gilbert Tournoy (1978) concerning the tragedy, of Ludwig Walther (1971) and Grazielle Gentilini (1983) concerning the comedy. Thus, by studying the similarities and the differences between these two works, we tried to define the originality of the author's dramatic aesthetic, as well as the respective places of each of both plays in the history of the reception of antiquity's poetic models, and of the constantly renewed development of the Latin humanist theatre

Le théâtre de Johannes Harmonius Marsus (étude dramaturgique et traduction)

Johannes Harmonius Marsus (Giovanni Armonio Marso), poéte humaniste vénitien de la fin du Quatrrocento, a composé en latin, entre autres, deux pièces de théâtre : une comédie intitulée Stephanium, très proche de la fabula palliata romaine, et une tragédie historique, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, pour célébrer l'entrée triomphale du roi français à Milan en 1499. Alors que la comédie a connu un succès retentissant dès sa première représentation et que, à l'inverse, la tragédie est restée complètement méconnue, il a paru important d'approfondir les caractéristiques dramaturgiques de ces deux pièces définies par la recherche constante de l'effet spectaculaire au service d'une intention édifiante. Notre traduction des deux pièces, la première en français, a ainsi été réalisée avec le souci de mettre en valeur le jeu scénique à travers lequel se dessine une nouvelle approche de la comédie et de la tragédie. L'étude du contexte d'écriture et la recherche des sources et modèles littéraires antiques (principalement Plaute et Térence d'une part, Sénèque et Claudien d'autre part) ont été réalisées dans le prolongement des travaux pionniers de Gilbert Tournoy (1978) pour la tragédie et de Ludwig Walther (1971) et Graziella Gentilini (1983) pour la comédie ; ainsi, par l'étude des similitudes et différences entre ces deux œuvres, nous avons essayé de définir l'originalité de l'esthétique dramatique de l'auteur ainsi que la place respective de chacune des deux pièces dans l'histoire de la réception des modèles poétiques de l'Antiquité et de l'élaboration, sans cesse renouvelée, du théâtre latin humanisteJohannes Harmonius Marsus (Giovanni Armonio Marso), a Venetian humanist poet ofthe end of the Quattrocento, composed in Latin, among others, two plays : a comedy entitled Stephanium, very similar to the Roman fabula palliata, and a historical tragedy, De Rebus Italicis deque Triumpho Ludovici XII Regis Francorum, in order to celebrate the triumphant entrance of the French king in Milan in 1499. As the comedy had a resounding success from its first performance, and the tragedy, on the contrary, has remained completely neglected, it seemed important to deepen the dramaturgical characteristics of these two plays which are defined by the constant pursuit of the spectacular effect, thus serving the intention of edifying and praising. Then in our translation of both plays, the first time in French, we were careful to emphasize the stage acting through which a new approach of comedy and tragedy is taking shape. The study of the context of writing and the search for the ancient literary sources and models (mainly Plautus and Terence on the one hand, Seneca and Claudian on the other hand) have been carried out following the pioneer works of Gilbert Tournoy (1978) concerning the tragedy, of Ludwig Walther (1971) and Grazielle Gentilini (1983) concerning the comedy. Thus, by studying the similarities and the differences between these two works, we tried to define the originality of the author's dramatic aesthetic, as well as the respective places of each of both plays in the history of the reception of antiquity's poetic models, and of the constantly renewed development of the Latin humanist theatre.METZ-SCD (574632105) / SudocSudocFranceF

H3K27me3 conditions chemotolerance in triple-negative breast cancer

International audienceThe persistence of cancer cells resistant to therapy remains a major clinical challenge. In triple-negative breast cancer, resistance to chemotherapy results in the highest recurrence risk among breast cancer subtypes. The drug-tolerant state seems largely defined by nongenetic features, but the underlying mechanisms are poorly understood. Here, by monitoring epigenomes, transcriptomes and lineages with single-cell resolution, we show that the repressive histone mark H3K27me3 (trimethylation of histone H3 at lysine 27) regulates cell fate at the onset of chemotherapy. We report that a persister expression program is primed with both H3K4me3 (trimethylation of histone H3 at lysine 4) and H3K27me3 in unchallenged cells, with H3K27me3 being the lock to its transcriptional activation. We further demonstrate that depleting H3K27me3 enhances the potential of cancer cells to tolerate chemotherapy. Conversely, preventing H3K27me3 demethylation simultaneously to chemotherapy inhibits the transition to a drug-tolerant state, and delays tumor recurrence in vivo. Our results highlight how chromatin landscapes shape the potential of cancer cells to respond to initial therapy