Involvement of the lipoxygenase pathway in the systemic resistance induced by Plant Growth-Promoting Rhizobacteria in tomato

Doctoral thesis (2013)

The treatment of plant roots with some Plant Growth Promoting Rhizobacteria (PGPR) results in the enhancement of the immune capacity of the host against phytopathogens. This phenomenon called Induced ... [more ▼]

The treatment of plant roots with some Plant Growth Promoting Rhizobacteria (PGPR) results in the enhancement of the immune capacity of the host against phytopathogens. This phenomenon called Induced Systemic Resistance (ISR) is observed in the whole plant and is effective against a broad spectrum of diseases. Many previous studies showed that this resistance is associated, in some pathosystems, with the stimulation of the key enzyme of the lipoxygenase (LOX) pathway. This defense pathway synthesizes antibiotic and signal compounds called oxylipins from poly unsaturated fatty acids. The main goal of our work was to analyse the involvement of the LOX pathway during the ISR in tomato plants The different steps of the pathway were analyzed at the transcriptional, enzymatic and metabolic levels in leaves of tomato plants elicited with the PGPR Pseudomonas putida BTP1, before and after infection by the fungal pathogen Botrytis cinerea. Our study showed that the bacterial treatment reprogrammed the LOX pathway. Before infection, the activity of the key enzyme of the pathway, the LOX, was higher in P. putida BTP1-treated plants compared to control plants. This stimulation resulted in the accumulation 13-hydroperoxy fatty acids and 13-hydroxyfatty acids conjugated to phospholipids and galactolipids. These products could constitute a pool of antifungal compounds that can be used during the pathogen attack. During the first days after B. cinerea inoculation, the LOX activity, the accumulation of one of its substrate (linolenic acid) and of its products were stimulated in treated plants as compared to control plants. The increase of LOX activity was caused by the induction of the expression level of two Lox genes: TomLoxD and TomLoxF. We observed a decrease of the pool of conjugated oxylipins and a concomitant increase of non conjugated oxylipins, associated with the stimulation of the phospholipase A2 activity. The branches of the pathway which can use the products of the LOX as substrate were differentially regulated resulting in the accumulation of fungitoxic oxylipins against B. cinerea. In order to determine if the induction of the LOX pathway is a general feature of the ISR in tomato, the effect of other PGPR and resistance elicitors produced by PGPR was analysed. Three pure bacterial elicitors sharing common biosurfactant features (the n-alkylated benzylamine derivative (NABD) produced by P. putida BTP1, the surfactin synthesized by many Bacillus strains and rhamnolipids purified from P. aeruginosa) and six Bacillus strains including strong, medium and non producers of surfactin were applied onto tomato roots. The analysis of the key points of the modulation of the LOX pathway showed that the plant molecular response depended on the studied organ (root / leaf), the nature of the elicitor and the amount of elicitor produced by the PGPR. In addition to our study on the involvement of the LOX pathway, we searched other mechanisms potentially induced in ISR-expressing plants. The combination of histological staining, quantification of enzymatic activities and analysis of the genome expression by hybridization on DNA gene chips showed additional defense genes and pathways involved in the resistance in tomato. In conclusion, our work showed that the LOX pathway is one of the defense mechanisms which can be involved in ISR in tomato. The elicitation of the resistance allows the plant to prepare to a future infection, and to respond faster and in a more effective way to a subsequent pathogen invasion. [less ▲]

Semantic Annotation of GPS Traces: Activity Type Inference

in Proceedings of the 92nd Annual Meeting of the Transportation Research Board (DVD-ROM) (2013)

Due to the rapid development of technology, larger data sets concerning activity travel behavior become available. These data sets often lack semantic interpretation. This implies that annotation in terms ... [more ▼]

Due to the rapid development of technology, larger data sets concerning activity travel behavior become available. These data sets often lack semantic interpretation. This implies that annotation in terms of activity type and transportation mode is necessary. This paper aims to infer activity types from GPS traces by developing a decision tree-based model. The model only considers activity start times and activity durations. Based on the decision tree classification, a probability distribution and a point prediction model were constructed. The probability matrix describes the probability of each activity type for each class (i.e. combination of activity start time and activity duration). In each class, the point prediction model selects the activity type that has the highest probability. Two types of data were collected in 2006 and 2007 in Flanders, Belgium, i.e. activity travel data and GPS data. The optimal classification tree constructed comprises 18 leaves. Consequently, 18 if-then rules were derived. An accuracy of 74% was achieved when training the tree. The accuracy of the model for the validation set, i.e. 72.5%, shows that overfitting is minimal. When applying the model to the test set, the accuracy was almost 76%. The models indicate the importance of time information in the semantic enrichment process. This study contributes to future data collection in that it enables researchers to directly infer activity types from activity start time and duration information obtained from GPS data. Because no location information is needed, this research can be easily and readily implemented to millions of individual agents. [less ▲]

Direct and indirect use of GFP whole cell biosensors for the assessment of bioprocess performances: design of milliliter scale-down bioreactors

in Biotechnology Progress (2013), 29(1), 48-59

Substrate limitation responsive biosensors have been used for the development of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional ... [more ▼]

Substrate limitation responsive biosensors have been used for the development of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli, i.e., uspA::gfp, csiE::gfp and yciG::gfp. Our previous studies have shown that these kinds of promoters are induced in response to substrate limitation and are significantly repressed when cultures are carried out in heterogeneous bioreactors. This sensitivity to substrate limitation has been confirmed in the case of the csiE and yciG biosensors. A mini-scale-down platform is proposed as a high throughput tool to rapidly investigate the usefulness of a given microbial biosensor. This platform is composed of shake flasks able to operate in fed-batch mode either using the slow release or the intermittent feeding principle. Local heterogeneities were reproduced at the level of these mini-bioreactors (operating under the intermittent feeding principle) and caused a decrease in GFP expression as in conventional scale-down reactors. The presence of GFP in supernatants was also noted and seems to be correlated with the substrate limitation signal for the three cultivation systems considered in this work (i.e., chemostat, conventional and mini-bioreactors) and with membrane permeability. [less ▲]

Human papillomavirus predicts the outcome following concomitant chemoradiotherapy in patients with head and neck squamous cell carcinomas.

in Oncology Reports (2013), 30(1), 371-6

We investigated the prevalence of human papillomavirus (HPV) in a clinical series of 72 patients with head and neck squamous cell carcinoma (HNSCC) using a retrospective and prospective study design. The ... [more ▼]

We investigated the prevalence of human papillomavirus (HPV) in a clinical series of 72 patients with head and neck squamous cell carcinoma (HNSCC) using a retrospective and prospective study design. The majority of patients were smokers and/or drinkers and were treated with concomitant chemoradiotherapy (CCR). Furthermore, we assessed the impact of HPV positivity on the response to CCR. Paraffin-embedded samples from HNSCC patients (n=72) were evaluated for the presence of HPV DNA using both GP5+/GP6+ consensus PCR and type-specific E6/E7 PCR to detect HPV types 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 67 and 68. The type-specific E6/E7 PCR demonstrated that 20 out of 69 HNSCC patients (29%) presented with high-risk (HR) HPV types and that 5 of the 69 HNSCC patients (7%) presented with low-risk (LR) HPV types. Using the GP5+/GP6+ PCR, we observed that the rate of response was statistically lower in the HPV+ group (P=0.02). Concerning patient outcomes in terms of recurrence and survival, we observed that the prognosis was poorer for HPV+ patients. We showed for the first time that patients with HPV+ HNSCC present with a worse prognosis after CCR. This observation highlights the need for prospective studies with large numbers of patients and a detailed history of tobacco and alcohol consumption before validating HPV as a marker of prognosis following CCR. [less ▲]

Expression of type 2 orexin receptor in human endometrium and its epigenetic silencing in endometrial cancer.

in Journal of Clinical Endocrinology and Metabolism (2013), 98(4), 1549-57

CONTEXT: Orexins A and B are neuropeptides that bind and activate 2 types of receptors. In addition to direct action in the brain, the orexinergic system has broader implications in peripheral organs, and ... [more ▼]

CONTEXT: Orexins A and B are neuropeptides that bind and activate 2 types of receptors. In addition to direct action in the brain, the orexinergic system has broader implications in peripheral organs, and it has been proposed to have a role in the induction of apoptosis. There are very few data on the endometrium. OBJECTIVE: The expression and epigenetic regulation of type 2 orexin receptor (OX2R) was investigated in the human endometrium as well as in endometrial endometrioid carcinoma (EEC). METHODS: OX2R localization was studied by immunohistochemistry in normal endometrium (n = 24) and in EEC (n = 32). The DNA methylation status of a CpG island located in the first exon of OX2R was analyzed by bisulfite sequencing in normal (n = 18), EEC (n = 34), and 3 endometrial cell lines. On the latter, mRNA expression and Western blotting as well as in vitro induction with orexin were performed. RESULTS: Expression of the OX2R protein was detected in normal endometrial epithelia, whereas it was frequently lacking in EEC. This loss was associated with hypermethylation of OX2R in EEC in comparison with normal endometrium (median CpG methylation percentages of 48.85% and 5.85%, respectively). In cell lines, hypermethylation correlated with weak OX2R expression. Additionally, in vitro treatment of the 3 EEC cell lines with orexins A and B did not result in proliferation change CONCLUSIONS: Altogether our data provide evidence for the epigenetic silencing of OX2R in EEC. The implication of the OX2R loss in tumoral progression remains to be elucidated. [less ▲]

Histology of the vaginal wall in women with pelvic organ prolapse: a literature review.

in International Urogynecology Journal (2013), sous presse

INTRODUCTION AND HYPOTHESIS: The pathophysiology of pelvic organ prolapse (POP) is incompletely understood. The purpose of this study is to describe the current knowledge about histology of the vaginal ... [more ▼]

INTRODUCTION AND HYPOTHESIS: The pathophysiology of pelvic organ prolapse (POP) is incompletely understood. The purpose of this study is to describe the current knowledge about histology of the vaginal wall and its possible involvement in the pathogenesis of pelvic organ prolapse. METHODS: Eligible studies were selected through a MEDLINE search covering January 1986 to December 2012. The research was limited to English-language publications. RESULTS: Investigations of changes in the vaginal tissue that occur in women with genital prolapse are currently still limited and produced contrary results. The heterogeneity of the patients and the control groups in terms of age, parity and hormonal status, of the localization of biopsies and the histological methods as well as the lack of validation of the quantification procedures do not allow clear and definitive conclusions to be drawn. CONCLUSIONS: This review shows that current knowledge of the histological changes observed in women with POP are inconclusive and relatively limited. More studies are needed in this specific field to better understand the mechanisms that lead to POP. [less ▲]

Deletion of cysteine cathepsins B or L yields differential impacts on murine skin proteome and degradome

in Molecular & Cellular Proteomics (2013), 12(3), 611-25

Numerous studies highlight that concerted proteolysis is essential for skin morphology and function. The cysteine protease cathepsin L (Ctsl) has been implicated in epidermal proliferation and ... [more ▼]

Numerous studies highlight that concerted proteolysis is essential for skin morphology and function. The cysteine protease cathepsin L (Ctsl) has been implicated in epidermal proliferation and desquamation as well as in hair cycle regulation. In stark contrast, mice deficient for cathepsin B (Ctsb) do not display an overt skin phenotype. To understand the systematic consequences of deleting Ctsb or Ctsl, we determined protein abundances of > 1300 proteins and proteolytic cleavage events in skin samples of wild-type, Ctsb-/- and Ctsl-/- mice by mass spectrometry based proteomics. Both protease deficiencies revealed distinct quantitative changes in proteome composition. Ctsl-/- skin revealed increased levels of the cysteine protease inhibitors cystatin B and cystatin M/E, increased cathepsin D and accumulation of the extracellular glycoprotein periostin. Immunohistochemistry located periostin predominantly in hypodermal connective tissue of Ctsl-/- skin. Proteomic identification of proteolytic cleavage sites within skin proteins revealed numerous processing sites that are underrepresented in Ctsl-/- or Ctsb-/- samples. Notably, few of the affected cleavage sites shared the canonical Ctsl or Ctsb specificity, providing further evidence for a complex proteolytic network in the skin. Novel processing sites in proteins such as dermokine and Notch-1 were detected. Simultaneous analysis of acetylated protein N-termini showed prototypical mammalian N-alpha acetylation. These results illustrate an influence of both Ctsb and Ctsl on the murine skin proteome and degradome with the phenotypic consequences of the absence of either protease differing considerably. [less ▲]

Investigation of the Determinants of Travelers’ Mental Knowledge of Public Parking Facilities

in Proceedings of the 92nd Annual Meeting of the Transportation Research Board (DVD-ROM) (2013)

This paper describes a study of car drivers’ familiarity with the parking situation in the vicinity of a regional shopping center. The data used for this study are collected in Hasselt, a medium sized ... [more ▼]

This paper describes a study of car drivers’ familiarity with the parking situation in the vicinity of a regional shopping center. The data used for this study are collected in Hasselt, a medium sized city in Belgium. The central shopping area of Hasselt is surrounded by 23 public parking facilities. 1007 residents have been asked to indicate if they are familiar with each parking facility. The concept of familiarity was related to the socio-demographic and cognitive attributes of the respondents, their trips to the city center and the type of parking facility using multinomial logistic regression and bivariate probit regression. The results show that familiarity with parking facilities is especially related to age and education, and to the frequency of car use towards the city centre, and to a lesser extent to place of residence, income and perceived mental knowledge. In addition to these results, this paper demonstrates the value of collecting virtual buffer data by means of an online survey tool. The authors recommend that simulation models that predict parking choice behavior take into account the different levels of familiarity with parking facilities, and the contributing factors. An important avenue for further research is the combination of personal and facility specific information to assess the familiarity with different types of parking facilities. [less ▲]

Decision making for teeth replacement in the esthetic area

Scientific conference (2013)

Esthetic results in dentistry are determined by the harmony between the dental prostheses and the soft tissues. To reach an optimal result, each single step of the treatment has a great importance, from ... [more ▼]

Esthetic results in dentistry are determined by the harmony between the dental prostheses and the soft tissues. To reach an optimal result, each single step of the treatment has a great importance, from the smile analyses to the final restoration delivery. The goal of this lecture is to describe how to elaborate a treatment planning for single and multiple tooth replacement in the aesthetic zone. A decision tree for the surgical protocols will be proposed according to our clinical experience at the university of Liège and, the current scientific evidences. The overall objective is, from an initial clinical situation, to determine the appropriate treatment approach and timing. The following scientific aspects will be developed: - The biological concept of extraction socket preservation. The use of biomaterials for alveolar bone augmentation or socket preservation. The goal is to clarify properties of the mostly used biomaterial in dentistry, as well as determine their clinical indications and limitations. Soft tissue management around teeth and implant [less ▲]

Validation of a French Version of a New Anxiety Trait Scale for Children

Poster (2013)

Anxiety diagnosis is relatively complex in children because intensity as well as symptoms of anxiety change during childhood (Bouden, Halayem, & Fakhfakh, 2002). The principal aim of this study was to ... [more ▼]

Anxiety diagnosis is relatively complex in children because intensity as well as symptoms of anxiety change during childhood (Bouden, Halayem, & Fakhfakh, 2002). The principal aim of this study was to validate through Confirmatory Factor Analyses (CFA) the a priori three-factor structure of the French version of the anxiety trait scale for children which includes psychological (“tend to be worried about everything”), behavioral (“tend to be upset, nervous or grumbling”), and somatic symptoms (“headache complaints”) of anxiety. This scale was previously found to discriminate, with high sensitivity and specificity, children with anxiety from control group. A first CFA performed on 288 6-12 year-old children showed an acceptable fit (2/df =2.66; RMSEA=.07 and CFI=.94). A second three-factor model was constructed and showed a better fit with a new sample of 287 children (2/df =2.18; RMSEA=.06 and CFI=.96), with a lower ECVI value for the model 2. For this model, the Cronbach’s alpha for each of the subscales ranged from .71 to .86, which confirmed the good internal reliability of the scale. This study provides a new three-factor structure for this anxiety scale and proposes normative data for French-speaking children. [less ▲]