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51.
Muriel Cario Catherine Pain Priscilla Kaulanjan‐Checkmodine Daniela Masia Gabriele Delia Vincent Casoli Pierre Costet Jean‐Franois Goussot Vronique Guyonnet‐Duperat Alice Bibeyran Khaled Ezzedine Corinne Reymermier Valrie Andre‐Frei Alain Taieb 《Pigment cell & melanoma research》2020,33(3):435-445
Human skin melanin pigmentation is regulated by systemic and local factors. According to the type of melanin produced by melanocytes, the transfer and degradation of melanosomes differ, thus accounting for most variations between ethnicities. We made the surprising observation that in a drastically changed environment, white and black phenotypes are reversible since Caucasian skin grafted onto nude mice can become black with all black phenotypic characteristics. Black xenografts differed essentially from other grafts by the levels of epidermal FGF‐2 and keratin 5. In vitro analysis confirmed that FGF‐2 directly regulates keratin 5. Interestingly, this phenomenon may be involved in human pathology. Keratin 5 mutations in Dowling–Degos Disease (DDD) have already been associated with the pheomelanosome–eumelanosome transition. In a DDD patient, keratin 5 was expressed in the basal and spinous layers, as observed in black xenografts. Furthermore, in a common age‐related hyperpigmentation disorder like senile lentigo (SL), keratin 5 distribution is also altered. In conclusion, modulation of keratin 5 expression and distribution either due to mutations or factors may account for the development of pigmentary disorders. 相似文献
52.
Raimo Hartmann Muriel C. F. van Teeseling Martin Thanbichler Knut Drescher 《Molecular microbiology》2020,114(1):140-150
Prokaryotic cells display a striking subcellular organization. Studies of the underlying mechanisms in different species have greatly enhanced our understanding of the morphological and physiological adaptation of bacteria to different environmental niches. The image analysis software tool BacStalk is designed to extract comprehensive quantitative information from the images of morphologically complex bacteria with stalks, flagella, or other appendages. The resulting data can be visualized in interactive demographs, kymographs, cell lineage plots, and scatter plots to enable fast and thorough data analysis and representation. Notably, BacStalk can generate demographs and kymographs that display fluorescence signals within the two-dimensional cellular outlines, to accurately represent their subcellular location. Beyond organisms with visible appendages, BacStalk is also suitable for established, non-stalked model organisms with common or uncommon cell shapes. BacStalk, therefore, contributes to the advancement of prokaryotic cell biology and physiology, as it widens the spectrum of easily accessible model organisms and enables highly intuitive and interactive data analysis and visualization. 相似文献
53.
Astrid Cruaud Grard Delvare Sabine Nidelet Laure Saun Sujeevan Ratnasingham Marguerite Chartois Bonnie B. Blaimer Michael Gates Sen G. Brady Sariana Faure Simon van Noort Jean‐Pierre Rossi Jean‐Yves Rasplus 《Cladistics : the international journal of the Willi Hennig Society》2021,37(1):1-35
Recent technical advances combined with novel computational approaches have promised the acceleration of our understanding of the tree of life. However, when it comes to hyperdiverse and poorly known groups of invertebrates, studies are still scarce. As published phylogenies will be rarely challenged by future taxonomists, careful attention must be paid to potential analytical bias. We present the first molecular phylogenetic hypothesis for the family Chalcididae, a group of parasitoid wasps, with a representative sampling (144 ingroups and seven outgroups) that covers all described subfamilies and tribes, and 82% of the known genera. Analyses of 538 Ultra‐Conserved Elements (UCEs) with supermatrix (RAx ML and IQTREE) and gene tree reconciliation approaches (ASTRAL, ASTRID) resulted in highly supported topologies in overall agreement with morphology but reveal conflicting topologies for some of the deepest nodes. To resolve these conflicts, we explored the phylogenetic tree space with clustering and gene genealogy interrogation methods, analyzed marker and taxon properties that could bias inferences and performed a thorough morphological analysis (130 characters encoded for 40 taxa representative of the diversity). This joint analysis reveals that UCEs enable attainment of resolution between ancestry and convergent/divergent evolution when morphology is not informative enough, but also shows that a systematic exploration of bias with different analytical methods and a careful analysis of morphological features is required to prevent publication of artifactual results. We highlight a GC content bias for maximum‐likelihood approaches, an artifactual mid‐point rooting of the ASTRAL tree and a deleterious effect of high percentage of missing data (>85% missing UCEs) on gene tree reconciliation methods. Based on the results we propose a new classification of the family into eight subfamilies and ten tribes that lay the foundation for future studies on the evolutionary history of Chalcididae. 相似文献
54.
Alejandro Ramirez Garcia Jianbo Zhang Anna Greppi Florentin Constancias Esther Wortmann Muriel Wandres Katherine Hurley Alberto Pascual-García Hans-Joachim Ruscheweyh Shana J. Sturla Christophe Lacroix Clarissa Schwab 《Environmental microbiology》2021,23(3):1765-1779
Glycerol/diol dehydratases (GDH) are enzymes that catalyse the production of propionate from 1,2-propanediol, and acrolein from glycerol. Acrolein reacts with dietary carcinogenic heterocyclic amines (HCA), reducing HCA mutagenicity, but is itself also an antimicrobial agent and toxicant. Gut microbial GDH activity has been suggested as an endogenous acrolein source; however, there is limited information on the potential of the intestinal microbiota to have GDH activity, and what impact it can have on the intestinal ecosystem and host health. We hypothesized that GDH activity of gut microbiota is determined by the abundance and distribution of GDH-active taxa and can be enhanced by supplementation of the GDH active Anaerobutyricum hallii, and tested this hypothesis combining quantitative profiling of gdh, model batch fermentations, microbiota manipulation, and kinetic modelling of acrolein formation. Our results suggest that GDH activity is a common trait of intestinal microbiota shared by a few taxa, which was dependent on overall gdh abundance. Anaerobutyricum hallii was identified as a key taxon in GDH metabolism, and its supplementation increased the rate of GDH activity and acrolein release, which enhanced the transformation of HCA and reduced fermentation activity. The findings of this first systematic study on acrolein release by intestinal microbiota indicate that dietary and microbial modulation might impact GDH activity, which may influence host health. 相似文献
55.
Sophie Bouvard Patrice Faure Corinne Roucard Alain Favier Serge Halimi 《Free radical research》2013,47(9):1017-1022
HeLa cell line stably transfected with the tat gene from human immunodeficiency virus type 1 has a decreased antioxidant potential. In this work, we used this model to investigate the effect of a high glucose level (20 mM) on the glucose induced cytotoxicity and on the antioxidant system. In comparison to cell culture under control medium, HeLa-wild cell cultured under 20 mM glucose did not exhibit necrosis or apoptosis, contrary to HeLa-tat cell presenting a significant increase in necrotic or apoptotic state. Moreover after 48 h culture under high glucose level the HeLa-tat proliferation rate was not higher than the one of HeLa-wild cells. In HeLa-wild cell high glucose level resulted in an induction of glutathione reductase activity in opposition to HeLa-tat cells where no change was observed. High glucose level resulted in 20% increase in GSSG/GSH ratio in HeLa-wild cells and 38% increase in HeLa-tat cells. Moreover, high glucose level resulted in a dramatic cytosolic thiol decrease and an important lipid peroxidation in HeLa-tat cells. No significant change of these two parameters was observed in HeLa-wild cells. In both cell lines, high glucose resulted in an increase of total SOD activity, as a consequence of the increase in Cu,Zn-SOD activity. High glucose did not result in an increase of Mn-SOD activity in both cell lines. As a consequence of tat tranfection Mn-SOD activity was 50% lower in HeLa-tat cells in comparison to HeLa-wild cells. This work emphasizes the importance of the antioxidant system in the glucose induced cytotoxicity. 相似文献
56.
Emmanuelle Braud Muriel Duflos Guillaume Le Baut Pierre Renard Bruno Pfeiffer Gordon Tucker 《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):253-257
The synthesis and pharmacological evaluation of new 3-(imidazol-4(5)-ylmethylene)-2,3-dihydrobenzo[b]furan-2-ones 8-10 and 3-(3,5-dimethylpyrrol-2-ylmethylene)-2,3-dihydrobenzo[b]furan-2-one 11, analogues of SU-5416, as potential inhibitors of angiogenesis, are reported. Compounds 8 and 11 were prepared by a Knoevenagel reaction starting from 2-hydroxyphenylacetic acid 2 and 4-formylimidazole 5 or 2-formyl-3,5-dimethylpyrrole 7, followed by acid-catalysed cyclodehydration. For compounds 9 and 10, an alternative method was used; it consisted in carrying out the Knoevenagel reaction with the 2,3-dihydrobenzo[b]furan-2-ones 3 and 4. The antiangiogenic activity of these compounds was evaluated in the three-dimensional in vitro rat aortic rings test at 1 μM. At this concentration, compound 11 induced a decrease of angiogenesis comparable to that observed with SU-5416; the vascular density index at 1 μM of 11 and SU-5416 were 30±10 and 22±4% of control, respectively. 相似文献
57.
France Bruck Ludovic Belle Chantal Lechanteur Laurence de Leval Muriel Hannon Sophie Dubois Emilie Castermans Stephanie Humblet-Baron Souad Rahmouni Yves Beguin Alexandra Briquet Frédéric Baron 《Cytotherapy》2013,15(3):267-279
Background aimsGraft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation caused by donor T cells reacting against host tissues. Previous studies have suggested that mesenchymal stromal cells (MSCs) could exert potent immunosuppressive effects.MethodsThe ability of human bone marrow derived MSCs to prevent xenogeneic GVHD in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice and in NOD/SCID/interleukin-2Rγ(null) (NSG) mice transplanted with human peripheral blood mononuclear cells (PBMCs) was assessed.ResultsInjection of 200 × 106 human PBMCs intraperitoneally (IP) into sub-lethally (3.0 Gy) irradiated NOD/SCID mice also given anti-asialo GM1 antibodies IP 1 day prior and 8 days after transplantation induced lethal xenogeneic GVHD in all tested mice. Co-injection of 2 × 106 MSCs IP on day 0 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs. Similarly, injection of 30 × 106 human PBMCs IP into sub-lethally (2.5 Gy) irradiated NSG mice induced a lethal xenogeneic GVHD in all tested mice. Injection of 3 × 106 MSCs IP on days 0, 7, 14 and 21 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs.ConclusionsInjection of MSCs did not prevent xenogeneic GVHD in these two humanized mice models. 相似文献
58.
59.
Anna Martinez Marie C. M. Halliez El Moukhtar Aliouat Magali Chabé Annie Standaert-Vitse Emilie Fréalle Nausicaa Gantois Muriel Pottier Anthony Pinon Eduardo Dei-Cas Cécile-Marie Aliouat-Denis 《PloS one》2013,8(11)
Pneumocystis organisms are airborne opportunistic pathogens that cannot be continuously grown in culture. Consequently, the follow-up of Pneumocystis stage-to-stage differentiation, the sequence of their multiplication processes as well as formal identification of the transmitted form have remained elusive. The successful high-speed cell sorting of trophic and cystic forms is paving the way for the elucidation of the complex Pneumocystis life cycle. The growth of each sorted Pneumocystis stage population was followed up independently both in nude rats and in vitro. In addition, by setting up a novel nude rat model, we attempted to delineate which cystic and/or trophic forms can be naturally aerially transmitted from host to host. The results showed that in axenic culture, cystic forms can differentiate into trophic forms, whereas trophic forms are unable to evolve into cystic forms. In contrast, nude rats inoculated with pure trophic forms are able to produce cystic forms and vice versa. Transmission experiments indicated that 12 h of contact between seeder and recipient nude rats was sufficient for cystic forms to be aerially transmitted. In conclusion, trophic- to cystic-form transition is a key step in the proliferation of Pneumocystis microfungi because the cystic forms (but not the trophic forms) can be transmitted by aerial route from host to host. 相似文献
60.
Muriel Mazet Pauline Morand Marc Biran Guillaume Bouyssou Pierrette Courtois Sylvie Daulouède Yoann Millerioux Jean-Michel Franconi Philippe Vincendeau Patrick Moreau Frédéric Bringaud 《PLoS neglected tropical diseases》2013,7(12)