Lin T.,University of Texas Health Science Center at Houston |
Gao L.,University of Texas Health Science Center at Houston |
Zhang C.,University of Texas Health Science Center at Houston |
Odeh E.,University of Texas Health Science Center at Houston |
And 6 more authors.
The identification of genes important in the pathogenesis of Lyme disease Borrelia has been hampered by exceedingly low transformation rates in low-passage, infectious organisms. Using the infectious, moderately transformable B. burgdorferi derivative 5A18NP1 and signature-tagged versions of the Himar1 transposon vector pGKT, we have constructed a defined transposon library for the efficient genome-wide investigation of genes required for wild-type pathogenesis, in vitro growth, physiology, morphology, and plasmid replication. To facilitate analysis, the insertion sites of 4,479 transposon mutants were determined by sequencing. The transposon insertions were widely distributed across the entire B. burgdorferi genome, with an average of 2.68 unique insertion sites per kb DNA. The 10 linear plasmids and 9 circular plasmids had insertions in 33 to 100 percent of their predicted genes. In contrast, only 35% of genes in the 910 kb linear chromosome had incapacitating insertions; therefore, the remaining 601 chromosomal genes may represent essential gene candidates. In initial signature-tagged mutagenesis (STM) analyses, 434 mutants were examined at multiple tissue sites for infectivity in mice using a semi-quantitative, Luminex-based DNA detection method. Examples of genes found to be important in mouse infectivity included those involved in motility, chemotaxis, the phosphoenolpyruvate phosphotransferase system, and other transporters, as well as putative plasmid maintenance genes. Availability of this ordered STM library and a high-throughput screening method is expected to lead to efficient assessment of the roles of B. burgdorferi genes in the infectious cycle and pathogenesis of Lyme disease. © 2012 Lin et al. Source
Dumas D.,University of Lorraine |
Henrionnet C.,University of Lorraine |
Hupont S.,University of Lorraine |
Werkmeister E.,Institute Of Biologie Of Lille |
And 3 more authors.
Bio-Medical Materials and Engineering
We propose an innovative invasiveless technique in the field of nonlinear optical imaging to facilitate monitoring of cell/scaffold combinations for tissue repair. By using a near infrared (NIR) femtosecond excitation, we were able to introduce a new index based on decay time response for fluorescence (F) and Second Harmonic Generation (SHG) obtained with Time Correlated Single Photon Counting (TCSPC) microscopy to monitor structural information on the state of the matrix collagen. Some human Mesenchymal Stem Cells (hMSCs) seeded in 3D scaffolds were tested with different culture times (from D7 to D56) to analyze the effect of Tumor Growth Factor beta 1 (TGF-β1) on type-2 collagen expression in the matrix. After 14 days in the presence of TGF-β1, our results showed an increase in the expression of type-2 collagen synthesized by hMSCs, and a change in collagen conformation, as an indication of its ability to be detected as a harmonophore by TCSPC-SHG without the need for an exogenous probe. © 2010 IOS Press and the authors. All rights reserved. Source
Moche H.,Institute Pasteur Of Lille |
Moche H.,Servier Group |
Moche H.,Lille 2 University of Health and Law |
Chevalier D.,Lille 2 University of Health and Law |
And 5 more authors.
With the increasing human exposure to nanoparticles (NP), the evaluation of their genotoxic potential is of significant importance. However, relevance for NP of the routinely used in vitro genotoxicity assays is often questioned, and a nanoparticulate reference positive control would therefore constitute an important step to a better testing of NP, ensuring that test systems are really appropriate. In this study, we investigated the possibility of using tungsten carbide-cobalt (WC-Co) NP as reference positive control in in vitro genotoxicity assays, including 2 regulatory assays, the mouse lymphoma assay and the micronucleus assay, and in the Comet assay, recommended for the toxicological evaluation of nanomedicines by the French Agency of Human Health Products (Afssaps). Through these assays, we were able to study different genetic endpoints in 2 cell types commonly used in regulatory genotoxicity assays: the L5178Y mouse lymphoma cell line and primary cultures of human lymphocytes. Our results showed that the use of WC-Co NP as positive control in in vitro genotoxicity assays was conceivable, but that different parameters have to be considered, such as cell type and treatment schedule. L5178Y mouse lymphoma cells did not provide satisfactory results in the 3 performed tests. However, human lymphocytes were more sensitive to genotoxic effects induced by WC-Co NP, particularly after a 24-h treatment in the in vitro micronucleus assay and after a 4-h treatment in the in vitro Comet assay. Under such conditions, WC-Co could be used as a nanoparticulate reference positive control in these assays. © The Author 2013. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. Source
Freville A.,University of Lille Nord de France |
Landrieu I.,Lille University of Science and Technology |
Garcia-Gimeno M.A.,Institute Biomedicina Of Valencia Csic |
Vicogne J.,Institute Of Biologie Of Lille |
And 8 more authors.
Journal of Biological Chemistry
Growing evidence indicates that the protein regulators governing protein phosphatase 1 (PP1) activity have crucial functions because their deletion drastically affects cell growth and division. PP1 has been found to be essential in Plasmodium falciparum, but little is known about its regulators. In this study, we have identified a homolog of Inhibitor-3 of PP1, named PfI3. NMR analysis shows that PfI3 belongs to the disordered protein family. High affinity interaction of PfI3 and PfPP1 is demonstrated in vitro using several methods, with an apparent dissociation constant K D of 100 nM. Wefurther show that the conserved 41KVVRW 45 motif is crucial for this interaction as the replacement of the Trp 45 by an Ala 45 severely decreases the binding to PfPP1. Surprisingly, PfI3 was unable to rescue a yeast strain deficient in I3 (Ypi1). This lack of functional orthology was supported as functional assays in vitro have revealed that PfI3, unlike yeast I3 and human I3, increases PfPP1 activity. Reverse genetic approaches suggest an essential role of PfI3 in the growth and/or survival of blood stage parasites because attempts to obtain knockout parasites were unsuccessful, although the locus of PfI3 is accessible. The main localization of a GFP-tagged PfI3 in the nucleus of all blood stage parasites is compatible with a regulatory role of PfI3 on the activity of nuclear PfPP1. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc. Source
Beulens J.W.J.,University Utrecht |
Van der Schouw Y.T.,University Utrecht |
Bergmann M.M.,German Institute of Human Nutrition |
Rohrmann S.,German Cancer Research Center |
And 40 more authors.
Journal of Internal Medicine
Objective: To investigate the association between alcohol consumption and type 2 diabetes, and determine whether this is modified by sex, body mass index (BMI) and beverage type. Design: Multicentre prospective case-cohort study. Setting: Eight countries from the European Prospective Investigation into Cancer and Nutrition cohort. Subjects: A representative baseline sample of 16154 participants and 12403 incident cases of type 2 diabetes. Interventions: Alcohol consumption assessed using validated dietary questionnaires. Main outcome measures: Occurrence of type 2 diabetes based on multiple sources (mainly self-reports), verified against medical information. Results: Amongst men, moderate alcohol consumption was nonsignificantly associated with a lower incidence of diabetes with a hazard ratio (HR) of 0.90 (95% CI: 0.78-1.05) for 6.1-12.0 versus 0.1-6.0gday-1, adjusted for dietary and diabetes risk factors. However, the lowest risk was observed at higher intakes of 24.1-96.0gday-1 with an HR of 0.86 (95% CI: 0.75-0.98). Amongst women, moderate alcohol consumption was associated with a lower incidence of diabetes with a hazard ratio of 0.82 (95% CI: 0.72-0.92) for 6.1-12.0gday-1 (P interaction gender <0.01). The inverse association between alcohol consumption and diabetes was more pronounced amongst overweight (BMI≥25kgm-2) than normal-weight men and women (P interaction<0.05). Adjusting for waist and hip circumference did not alter the results for men, but attenuated the association for women (HR=0.90, 95% CI: 0.79-1.03 for 6.1-12.0gday-1). Wine consumption for men and fortified wine consumption for women were most strongly associated with a reduced risk of diabetes. Conclusions: The results of this study show that moderate alcohol consumption is associated with a lower risk of type 2 diabetes amongst women only. However, this risk reduction is in part explained by fat distribution. The relation between alcohol consumption and type 2 diabetes was stronger for overweight than normal-weight women and men. © 2012 The Association for the Publication of the Journal of Internal Medicine. Source