Biodistribution of a high dose of diamond, graphite, and graphene oxide nanoparticles after multiple intraperitoneal injections in rats

Carbon nanoparticles have recently drawn intense attention in biomedical applications. Hence, there is a need for further in vivo investigations of their biocompatibility and biodistribution via various exposure routes. We hypothesized that intraperitoneally injected diamond, graphite, and graphene oxide nanoparticles may have different biodistribution and exert different effects on the intact organism. Forty Wistar rats were divided into four groups: the control and treated with nanoparticles by intraperitoneal injection (4 mg of nanoparticles/kg body weight) eight times during the 4-week period. Blood was collected for evaluation of blood morphology and biochemistry parameters. Photographs of the general appearance of each rat’s interior were taken immediately after sacrifice. The organs were excised and their macroscopic structure was visualized using a stereomicroscope. The nanoparticles were retained in the body, mostly as agglomerates. The largest agglomerates (up to 10 mm in diameter) were seen in the proximity of the injection place in the stomach serous membrane, between the connective tissues of the abdominal skin, muscles, and peritoneum. Numerous smaller, spherical-shaped aggregates (diameter around 2 mm) were lodged among the mesentery. Moreover, in the connective and lipid tissue in the proximity of the liver and spleen serosa, small aggregates of graphite and graphene oxide nanoparticles were observed. However, all tested nanoparticles did not affect health and growth of rats. The nanoparticles had no toxic effects on blood parameters and growth of rats, suggesting their potential applicability as remedies or in drug delivery systems

Analysis of the link between the redox state and enzymatic activity of the HtrA (DegP) protein from Escherichia coli

Bacterial HtrAs are proteases engaged in extracytoplasmic activities during stressful conditions and pathogenesis. A model prokaryotic HtrA (HtrA/DegP from Escherichia coli) requires activation to cleave its substrates efficiently. In the inactive state of the enzyme, one of the regulatory loops, termed LA, forms inhibitory contacts in the area of the active center. Reduction of the disulfide bond located in the middle of LA stimulates HtrA activity in vivo suggesting that this S-S bond may play a regulatory role, although the mechanism of this stimulation is not known. Here, we show that HtrA lacking an S-S bridge cleaved a model peptide substrate more efficiently and exhibited a higher affinity for a protein substrate. An LA loop lacking the disulfide was more exposed to the solvent; hence, at least some of the interactions involving this loop must have been disturbed. The protein without S-S bonds demonstrated lower thermal stability and was more easily converted to a dodecameric active oligomeric form. Thus, the lack of the disulfide within LA affected the stability and the overall structure of the HtrA molecule. In this study, we have also demonstrated that in vitro human thioredoxin 1 is able to reduce HtrA; thus, reduction of HtrA can be performed enzymatically

Contrasting effect of dark-chilling on chloroplast structure and arrangement of chlorophyll-protein complexes in pea and tomato: plants with a different susceptibility to non-freezing temperature

The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl a/b ratio in thylakoids of both species. A decline of Chl a fluorescence intensity and an increase of the ratio of fluorescence intensities of PSI and PSII at 120 K was observed after dark-chilling in thylakoids isolated from tomato, but not from pea leaves. Chilling of pea leaves induced an increase of the relative contribution of LHCII and PSII fluorescence. A substantial decrease of the LHCII/PSII fluorescence accompanied by an increase of that from LHCI/PSI was observed in thylakoids from chilled tomato leaves; both were attenuated by photoactivation. Chlorophyll fluorescence of bright grana discs in chloroplasts from dark-chilled leaves, detected by confocal laser scanning microscopy, was more condensed in pea but significantly dispersed in tomato, compared with control samples. The chloroplast images from transmission-electron microscopy revealed that dark-chilling induced an increase of the degree of grana stacking only in pea chloroplasts. Analyses of O-J-D-I-P fluorescence induction curves in leaves of CS tomato before and after recovery from chilling indicate changes in electron transport rates at acceptor- and donor side of PS II and an increase in antenna size. In CT pea leaves these effects were absent, except for a small but irreversible effect on PSII activity and antenna size. Thus, the differences in chloroplast structure between CS and CT plants, induced by dark-chilling are a consequence of different thylakoid supercomplexes rearrangements

Le charme discret de la censure au cinéma en République Populaire de Pologne entre 1956 – 1981

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Figure de Dibbouk dans le film de Michal Waszynski, un lieu de mémoire de la culture Yiddish

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Le dibbouk de Michal Waszynski (1937) : entre la magie et le mysticisme

International audienceDybbuk, in the folklore of Hassidic Jews in Eastern Europe, is a spirit of a dead man who takes possession of the body of the person to whom he was attached in his lifetime. Michal Waszynski's "The Dybbuk", shot in Poland in 1937, set on stage this figure, based on the play by Sholem An-Ski, a Russian ethnographer, and on the expressionist aesthetics. Waszynski's film is a fiction witness that contains traces of the existence of Yiddish culture and the magical beliefs of Eastern European Jews before the Second World War, from which the legend of Dybbuk is originated. Our article questions the images of magic and mysticism present in Waszynski's film in order to apprehend the self-representation of a disappeared world

DOCS ICI, COURTS LÀ : UNE ALTERNATIVE DE DIFFUSION POUR LES FILMS REGIONAUX EN BOURGOGNE-FRANCHE-COMTÉ ?

sous la direction de Christel Taillibert, Jean-Paul Aubert et de Cyril LavergerInternational audienceDocs ici, courts là est un dispositif qui valorise les courts métrages et les documentaires produits et/ou réalisés en Bourgogne-Franche-Comté. À travers cette étude de cas, l’auteure rend compte de ses observations et de ses questionnements sur la portée alternative de ce dispositif qui se décline à plusieurs niveaux. Il est complémentaire ou alternatif aux modes de diffusion de films standards (salles de cinéma, festivals, télévision), lorsque les œuvres sont projetées dans des lieux « atypiques ». Mais sa portée alternative se révèle sur d’autres de ses aspects et actions qu’il met en place. Docs ici, courts là peut être considéré comme alternatif par son mode de fonctionnement associatif qui lui donne la liberté d’initier des partenariats originaux pour valoriser les films de la région Bourgogne-Franche-Comté. Il diffuse des films « hors du système » et permet leur accès à des personnes éloignées de la culture. Sa portée alternative s’exprime également dans son potentiel de médiation culturelle qui tisse un lien social entre les œuvres, leurs créateurs et les publics. Enfin, il permet aussi des ouvertures étonnantes

Beata Waligorska-Olejniczak, Literackie konstelacje (w) twórczości Andrieja Zwiagnicewa (Les constellations littéraires dans l’œuvre d’Andreï Zviaguintsev), compte-rendu

compte-rendu, paru dans le numéro 6/2023 de CompLi

L’Auteur-cinéaste polonais face aux critiques français dans les années 1970

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L’évasion du cinéma liberté (1990) de Wojciech Marczewski – un métafilm de la fin du communisme polonais

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