Laboratoire Of Biologie Cellulaire Et Moleculaire

Monastir, Tunisia

Laboratoire Of Biologie Cellulaire Et Moleculaire

Monastir, Tunisia
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Perchepied L.,French National Institute for Agricultural Research | Balague C.,French National Institute for Agricultural Research | Riou C.,French National Institute for Agricultural Research | Claudel-Renard C.,Laboratoire Of Biologie Cellulaire Et Moleculaire | And 3 more authors.
Molecular Plant-Microbe Interactions | Year: 2010

Studies of the interaction between Arabidopsis thaliana and the necrotrophic fungal pathogen Sclerotinia sclerotiorum have been hampered by the extreme susceptibility of this model plant to the fungus. In addition, analyses of the plant defense response suggested the implication of a complex interplay of hormonal and signaling pathways. To get a deeper insight into this host-pathogen interaction, we first analyzed the natural variation in Arabidopsis for resistance to S. sclerotiorum. The results revealed a large variation of resistance and susceptibility in Arabidopsis, with some ecotypes, such as Ws-4, Col-0, and Rbz-1, being strongly resistant, and others, such as Shahdara, Ita-0, and Cvi-0, exhibiting an extreme susceptibility. The role of different signaling pathways in resistance was then determined by assessing the symptoms of mutants affected in the perception, production, or transduction of hormonal signals after inoculation with S. sclerotiorum. This analysis led to the conclusions that i) signaling of inducible defenses is predominantly mediated by jasmonic acid and abscisic acid, influenced by ethylene, and independent of salicylic acid; and ii) nitric oxide (NO) and reactive oxygen species are important signals required for plant resistance to S. sclerotiorum. Defense gene expression analysis supported the specific role of NO in defense activation. © 2010 The American Phytopathological Society.

Javelle M.,CNRS Laboratory of Plant Reproduction and Development | Javelle M.,Cold Spring Harbor Laboratory | Vernoud V.,CNRS Laboratory of Plant Reproduction and Development | Depege-Fargeix N.,CNRS Laboratory of Plant Reproduction and Development | And 5 more authors.
Plant Physiology | Year: 2010

Transcription factors of the homeodomain-leucine zipper IV (HD-ZIP IV) family play crucial roles in epidermis-related processes. To gain further insight into the molecular function of OUTER CELL LAYER1 (OCL1), 14 target genes up- or down-regulated in transgenic maize (Zea mays) plants overexpressing OCL1 were identified. The 14 genes all showed partial coexpression with OCL1 in maize organs, and several of them shared preferential expression in the epidermis with OCL1. They encoded proteins involved in lipid metabolism, defense, envelope-related functions, or cuticle biosynthesis and include ZmWBC11a (for white brown complex 11a), an ortholog of AtWBC11 involved in the transport of wax and cutin molecules. In support of the annotations, OCL1-overexpressing plants showed quantitative and qualitative changes of cuticular wax compounds in comparison with wild-type plants. An increase in C24 to C28 alcohols was correlated with the transcriptional up-regulation of ZmFAR1, coding for a fatty acyl-coenzyme A reductase. Transcriptional activation of ZmWBC11a by OCL1 was likely direct, since transactivation in transiently transformed maize kernels was abolished by a deletion of the activation domain in OCL1 or mutations in the L1 box, a cis-element bound by HD-ZIP IV transcription factors. Our data demonstrate that, in addition to AP2/EREBP and MYB-type transcription factors, members of the HD-ZIP IV family contribute to the transcriptional regulation of genes involved in cuticle biosynthesis. © 2010 American Society of Plant Biologists.

Jacquin E.,University of Franche Comte | Jacquin E.,ANR Inc | Jacquin E.,Laboratoire Of Biologie Cellulaire Et Moleculaire | Guenat D.,University of Franche Comte | And 11 more authors.
Virologie | Year: 2014

High-risk human Papillomaviruses (HR-HPV) - the most carcinogenic infectious agents - are responsible for the development of cervical cancer. The knowledge of HPV infection natural history and viral carcinogenesis led to the investigation of viral biomarkers (genotype, viral load, integration, E6/E7 mRNA expression, viral DNA methylation) from clinical samples representative of the evolution of cervical lesions. Mostly concerning HPV16, the literature data agree on an increase of viral load, proportion of samples harboring integrated HPV genomes and methylation of CpG located in the L1 gene with the lesion severity. Viral load and L1 CpG methylation are interesting for clinical practice since appropriate cutoff values allow the identification of precancerous lesions with a high specificity. Although HPV E6/E7 transcript detection is more specific than HPV DNA detection to identify precancerous cervical lesions, viral transcript quantitation and cutoff value determination are unlikely feasible in clinical practice. Taken together, data highlight promising biomarkers that could be integrated to screening algorithms.

Chaabane F.,University of Monastir | Krifa M.,University of Monastir | Matera E.,French Institute of Health and Medical Research | Loussaeif A.,University of Monastir | And 5 more authors.
Tumor Biology | Year: 2014

The antiproliferative potential of extracts of Daphne gnidium L. (Thymelaeaceae) on K562 cells was assessed, and the capacity of these extracts to disturb the cell cycle of K562 cells and to inhibit human P-glycoprotein was evaluated. The antiproliferative activity was evaluated using the MTT assay. The cell cycle analysis and the inhibition of P-glycoprotein were tested by flow cytometry. All the tested extracts exhibited significant anti-proliferative effects. Ethyl acetate extract has the strongest cytotoxic effect with an IC50 of 18.5 μg/ml. Furthermore, cell cycle analysis revealed that cells treated with chloroform, butanol and aqueous extracts were arrested predominantly in G2-M phase. Butanol extract was the most active extract. Percentage of cells arrested in G2-M was 34 %, 36.67 % and 42.63 % respectively, after treatment with 25, 75 and 100 μg/ml of the extract, versus 19 % in the cells treated with the vehicle solvent. In addition, chloroform extract had the ability to inhibit human P-glycoprotein-mediated daunorubicin in K562/R7 leukaemic cells in a dose-dependent manner compared to the positive control, cyclosporin A. These findings demonstrate that extracts from D. gnidium leaves have antileukaemic activity by perturbing the cell cycle of K562 and inhibiting human P-glycoprotein in K562/R7 cell line. © 2014, International Society of Oncology and BioMarkers (ISOBM).

Plissonnier M.L.,Laboratoire Of Biologie Cellulaire Et Moleculaire | Fauconnet S.,Laboratoire Of Biologie Cellulaire Et Moleculaire | Fauconnet S.,Besancon University Hospital Center | Bittard H.,Besancon University Hospital Center | Lascombe I.,Laboratoire Of Biologie Cellulaire Et Moleculaire
International Journal of Cancer | Year: 2010

Thiazolidinediones, including rosiglitazone and troglitazone, are insulin-sensitizing drugs and high-affinity ligands for the peroxisome proliferator-activated receptor ? (PPAR?). Apart from their antidiabetic activity, these molecules possess antitumor properties. We investigated their potential apoptotic effects on RT4 (derived from a well-differentiated Grade I papillary tumor) and T24 (derived from an undifferentiated Grade III carcinoma) bladder cancer cells. Rosiglitazone induced G2/M or G0/G1 phase cell cycle arrest in RT4 and T24 cells, respectively. Only troglitazone triggered apoptosis via extrinsic and intrinsic pathways in both cell lines. Interestingly, rosiglitazone amplified TRAIL-induced apoptosis in TRAIL-sensitive RT4 cells or let TRAIL-resistant T24 cells to respond to TRAIL. Thiazolidinediones acted through PPAR? activation-independent mechanisms. The underlying mechanisms involved for the first time in cancer cells the upregulation of soluble and/or membrane-bound TRAIL. This was associated with increased cell surface death receptor 5 expression and c-FLIP and survivin downregulation, mediated in part through proteasome-dependent degradation in troglitazone-promoted cell death. Therefore, the combination of rosiglitazone and TRAIL could be clinically relevant as chemopreventive or therapeutic agents for the treatment of TRAIL-resistant high-grade urothelial cancers. © 2010 UICC.

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