43 results on '"Bertrand S"'
Search Results
2. Salmonella Typhimurium DT193 and DT99 are present in great and blue tits in Flanders, Belgium
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Boonyarittichaikij, R., primary, Verbrugghe, E., additional, Dekeukeleire, D., additional, De Beelde, R., additional, Rouffaer, L. O., additional, Haesendonck, R., additional, Strubbe, D., additional, Mattheus, W., additional, Bertrand, S., additional, Pasmans, F., additional, Bonte, D., additional, Verheyen, K., additional, Lens, L., additional, and Martel, A., additional
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- 2017
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3. Diversity of Listeria monocytogenes Strains of Clinical and Food Chain Origins in Belgium between 1985 and 2014
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Bertrand, S., primary, Ceyssens, P. J., additional, Yde, M., additional, Dierick, K., additional, Boyen, F., additional, Vanderpas, J., additional, Vanhoof, R., additional, and Mattheus, W., additional
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- 2016
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4. Hypercoagulability in critically ill patients with COVID 19, an observational prospective study.
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Laure Calvet, François Thouy, Olivier Mascle, Anne-Françoise Sapin, Kévin Grapin, Jean Mathias Liteaudon, Bertrand Evrard, Benjamin Bonnet, Mireille Adda, Bertrand Souweine, and Claire Dupuis
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Medicine ,Science - Abstract
ObjectiveCOVID 19 is often associated with hypercoagulability and thromboembolic (TE) events. The aim of this study was to assess the characteristics of hypercoagulability and its relationship with new-onset TE events and the composite outcome of need for intubation and/or death in intensive care unit (ICU) patients admitted for COVID.DesignProspective observational study.SettingMonocentric, intensive care, University Hospital of Clermont Ferrand, France.PatientsPatients admitted to intensive care from January 2020 to May 2021 for COVID-19 pneumonia.InterventionsStandard hemostatic tests and rotational thromboelastometry (ROTEM) were performed on admission and on day 4. Hypercoagulability was defined by at least one of the following criteria: D-dimers > 3000 μg/dL, fibrinogen > 8 g/L, EXTEM CFT below the normal range, EXTEM A5, MCF, Li 60 above the normal range, and EXTEM G-score ((5000 x MCF) / (100-MCF)) ≥ 11 dyne/cm2.Measurements and main resultsOf the 133 patients included, 17 (12.7%) developed new-onset TE events, and 59 (44.3%) required intubation and/or died in the ICU. ROTEM was performed in 133 patients on day 1 and in 67 on day 4. Hypercoagulability was present on day 1 in 115 (86.4%) patients. None of the hypercoagulability indices were associated with subsequent new-onset TE events on days 1 and 4 nor with the need for intubation and/or ICU death. Hyperfibrinogenemia > 8g/dL, higher D-dimers and higher EXTEM Li 60 on day 4 were predictive of need for intubation and/or of ICU death.ConclusionsOur study confirmed that most COVID-19 ICU patients have hypercoagulability on admission and almost all on day 4. Hyperfibrinogenemia or fibrinolysis shutdown on day 4 were associated with unfavorable outcome.
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- 2022
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5. Some bee-pollinated plants provide nutritionally incomplete pollen amino acid resources to their pollinators.
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Léna Jeannerod, Archibald Carlier, Bertrand Schatz, Clothilde Daise, Aurore Richel, Yannick Agnan, Mathilde Baude, and Anne-Laure Jacquemart
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Medicine ,Science - Abstract
For pollinators such as bees, nectar mainly provides carbohydrates and pollen provides proteins, amino acids, and lipids to cover their nutritional needs. Here, to examine differences in pollinator resources, we compared the amino acid profiles and total amino acid contents of pollen from 32 common entomophilous plants in seven families. Our results showed that the amino acid profiles and contents in pollen samples differed according to the plant family and the chromatography method used, i.e., high-performance liquid chromatography (HPLC) versus ion exchange chromatography (IEX). Pollen from Boraginaceae species had the highest total amino acid contents (361.2-504 μg/mg) whereas pollen from the Malvaceae family had the lowest total amino acid contents (136-243.1 μg/mg). Calculating an amino acid score (AAS) that reflects pollen nutritional quality showed that slightly less than half of the species (19 out of 32) had the maximum nutritional score (AAS = 1) and offered high nutritional quality pollen amino acids for bee pollinators. Though they had high total amino acid contents, the amino acid composition of the studied Boraginaceae species and several members of the Fabaceae was not optimal, as their pollen was deficient in some essential amino acids, resulting in suboptimal amino acid scores (AAS < 0.7). Except for cysteine, the measured amino acid contents were higher using IEX chromatography than using HPLC. IEX chromatography is more robust and is to be preferred over HPLC in future amino acid analyses. Moreover, our observations show that some bee-pollinated species fail to provide complete amino acid resources for their pollinators. Although the implications for pollinator behavior remain to be studied, these deficiencies may force pollinators to forage from different species to obtain all nutritionial requirements.
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- 2022
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6. Impact of early corticosteroids on 60-day mortality in critically ill patients with COVID-19: A multicenter cohort study of the OUTCOMEREA network
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Claire Dupuis, Etienne de Montmollin, Niccolò Buetti, Dany Goldgran-Toledano, Jean Reignier, Carole Schwebel, Julien Domitile, Mathilde Neuville, Moreno Ursino, Shidasp Siami, Stéphane Ruckly, Corinne Alberti, Bruno Mourvillier, Sebastien Bailly, Virginie Laurent, Marc Gainnier, Bertrand Souweine, Jean-François Timsit, and on behalf of the OutcomeRea research network
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Medicine ,Science - Abstract
Objectives In severe COVID-19 pneumonia, the appropriate timing and dosing of corticosteroids (CS) is not known. Patient subgroups for which CS could be more beneficial also need appraisal. The aim of this study was to assess the effect of early CS in COVID-19 pneumonia patients admitted to the ICU on the occurrence of 60-day mortality, ICU-acquired-bloodstream infections(ICU-BSI), and hospital-acquired pneumonia and ventilator-associated pneumonia(HAP-VAP). Methods We included patients with COVID-19 pneumonia admitted to 11 ICUs belonging to the French OutcomeReaTM network from January to May 2020. We used survival models with ponderation with inverse probability of treatment weighting (IPTW). Results The study population comprised 303 patients having a median age of 61.6 (53–70) years of whom 78.8% were male and 58.6% had at least one comorbidity. The median SAPS II was 33 (25–44). Invasive mechanical ventilation was required in 34.8% of the patients. Sixty-six (21.8%) patients were in the Early-C subgroup. Overall, 60-day mortality was 29.4%. The risks of 60-day mortality (IPTWHR = 0.86;95% CI 0.54 to 1.35, p = 0.51), ICU-BSI and HAP-VAP were similar in the two groups. Importantly, early CS treatment was associated with a lower mortality rate in patients aged 60 years or more (IPTWHR, 0.53;95% CI, 0.3–0.93; p = 0.03). In contrast, CS was associated with an increased risk of death in patients younger than 60 years without inflammation on admission (IPTWHR = 5.01;95% CI, 1.05, 23.88; p = 0.04). Conclusion For patients with COVID-19 pneumonia, early CS treatment was not associated with patient survival. Interestingly, inflammation and age can significantly influence the effect of CS.
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- 2021
7. Clinical and biological clusters of sepsis patients using hierarchical clustering
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Grégory Papin, Sébastien Bailly, Claire Dupuis, Stéphane Ruckly, Marc Gainnier, Laurent Argaud, Elie Azoulay, Christophe Adrie, Bertrand Souweine, Dany Goldgran-Toledano, Guillaume Marcotte, Antoine Gros, Jean Reignier, Bruno Mourvillier, Jean-Marie Forel, Romain Sonneville, Anne-Sylvie Dumenil, Michael Darmon, Maité Garrouste-Orgeas, Carole Schwebel, Jean-François Timsit, and OUTCOMEREA study group
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Medicine ,Science - Abstract
Background Heterogeneity in sepsis expression is multidimensional, including highly disparate data such as the underlying disorders, infection source, causative micro-organismsand organ failures. The aim of the study is to identify clusters of patients based on clinical and biological characteristic available at patients’ admission. Methods All patients included in a national prospective multicenter ICU cohort OUTCOMEREA and admitted for sepsis or septic shock (Sepsis 3.0 definition) were retrospectively analyzed. A hierarchical clustering was performed in a training set of patients to build clusters based on a comprehensive set of clinical and biological characteristics available at ICU admission. Clusters were described, and the 28-day, 90-day, and one-year mortality were compared with log-rank rates. Risks of mortality were also compared after adjustment on SOFA score and year of ICU admission. Results Of the 6,046 patients with sepsis in the cohort, 4,050 (67%) were randomly allocated to the training set. Six distinct clusters were identified: young patients without any comorbidities, admitted in ICU for community-acquired pneumonia (n = 1,603 (40%)); young patients without any comorbidities, admitted in ICU for meningitis or encephalitis (n = 149 (4%)); elderly patients with COPD, admitted in ICU for bronchial infection with few organ failures (n = 243 (6%)); elderly patients, with several comorbidities and organ failures (n = 1,094 (27%)); patients admitted after surgery, with a nosocomial infection (n = 623 (15%)); young patients with immunosuppressive conditions (e.g., AIDS, chronic steroid therapy or hematological malignancy) (n = 338 (8%)). Clusters differed significantly in early or late mortality (p < .001), even after adjustment on severity of organ dysfunctions (SOFA) and year of ICU admission. Conclusions Clinical and biological features commonly available at ICU admission of patients with sepsis or septic shock enabled to set up six clusters of patients, with very distinct outcomes. Considering these clusters may improve the care management and the homogeneity of patients in future studies.
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- 2021
8. One year after ICU admission for severe community-acquired pneumonia of bacterial, viral or unidentified etiology. What are the outcomes?
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Frédéric Sangla, David Legouis, Pierre-Emmanuel Marti, Sebastian D Sgardello, Amélie Brebion, Pierre Saint-Sardos, Mireille Adda, Alexandre Lautrette, Bruno Pereira, and Bertrand Souweine
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Medicine ,Science - Abstract
IntroductionMultiplex polymerase chain reaction (mPCR) for respiratory virus testing is increasingly used in community-acquired pneumonia (CAP), however data on one-year outcome in intensive care unit (ICU) patients with reference to the causative pathogen are scarce.Materials and methodsWe performed a single-center retrospective study in 123 ICU patients who had undergone respiratory virus testing for CAP by mPCR and with known one-year survival status. Functional status including dyspnea (mMRC score), autonomy (ADL Katz score) and need for new home-care ventilatory support was assessed at a one-year post-ICU follow-up. Mortality rates and functional status were compared in patients with CAP of a bacterial, viral or unidentified etiology one year after ICU admission.ResultsThe bacterial, viral and unidentified groups included 19 (15.4%), 37 (30.1%), and 67 (54.5%) patients, respectively. In multivariate analysis, one-year mortality in the bacterial group was higher compared to the viral group (HR 2.92, 95% CI 1.71-7.28, p = 0.02) and tended to be higher compared to the unidentified etiology group (p = 0.06); but no difference was found between the viral and the unidentified etiology group (p = 0.43). In 64/83 one-year survivors with a post-ICU follow-up consultation, there were no differences in mMRC score, ADL Katz score and new home-care ventilatory support between the groups (p = 0.52, p = 0.37, p = 0.24, respectively). Severe dyspnea (mMRC score = 4 or death), severe autonomy deficiencies (ADL Katz score ≤ 2 or death), and major adverse respiratory events (new home-care ventilatory support or death) were observed in 52/104 (50.0%), 47/104 (45.2%), and 65/104 (62.5%) patients, respectively; with no difference between the bacterial, viral and unidentified group: p = 0.58, p = 0.06, p = 0.61, respectively.ConclusionsCAP of bacterial origin had a poorer outcome than CAP of viral or unidentified origin. At one-year, impairment of functional status was frequently observed, with no difference according to the etiology.
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- 2020
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9. Cost-effectiveness analysis of chlorhexidine-alcohol versus povidone iodine-alcohol solution in the prevention of intravascular-catheter-related bloodstream infections in France.
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Franck Maunoury, Christian Farinetto, Stéphane Ruckly, Jeremy Guenezan, Jean-Christophe Lucet, Alain Lepape, Julien Pascal, Bertrand Souweine, Olivier Mimoz, and Jean-François Timsit
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Medicine ,Science - Abstract
OBJECTIVE:To perform a cost-effectiveness analysis of skin antiseptic solutions (chlorhexidine-alcohol (CHG) versus povidone iodine-alcohol solution (PVI)) for the prevention of intravascular-catheter-related bloodstream infections (CRBSI) in intensive care unit (ICU) in France based on an open-label, multicentre, randomised, controlled trial (CLEAN). DESIGN:A 100-day time semi-markovian model was performed to be fitted to longitudinal individual patient data from CLEAN database. This model includes eight health states and probabilistic sensitivity analyses on cost and effectiveness were performed. Costs of intensive care unit stay are based on a French multicentre study and the cost-effectiveness criterion is the cost per patient with catheter-related bloodstream infection avoided. PATIENTS:2,349 patients (age≥18 years) were analyzed to compare the 1-time CHG group (CHG-T1, 588 patients), the 4-time CHG group (CHG-T4, 580 patients), the 1-time PVI group (PVI-T1, 587 patients), and the 4-time PVI group (PVI-T4, 594 patients). INTERVENTION:2% chlorhexidine-70% isopropyl alcohol (chlorhexidine-alcohol) compared to 5% povidone iodine-69% ethanol (povidone iodine-alcohol). RESULTS:The mean cost per alive, discharged or dead patient was of €23,798 (95% confidence interval: €20,584; €34,331), €21,822 (€18,635; €29,701), €24,874 (€21,011; €31,678), and €24,201 (€20,507; €29,136) for CHG-T1, CHG-T4, PVI-T1, and PVI-T4, respectively. The mean number of patients with CRBSI per 1000 patients was of 3.49 (0.42; 12.57), 6.82 (1.86; 17.38), 26.04 (14.64; 42.58), and 23.05 (12.32; 39.09) for CHG-T1, CHG-T4, PVI-T1, and PVI-T4, respectively. In comparison to the 1-time PVI solution, the 1-time CHG solution avoids 22.55 CRBSI /1,000 patients, and saves €1,076 per patient. This saving is not statistically significant at a 0.05 level because of the overlap of 95% confidence intervals for mean costs per patient in each group. Conversely, the difference in effectiveness between the CHG-T1 solution and the PVI-T1 solution is statistically significant. CONCLUSIONS:The CHG-T1 solution is more effective at the same cost than the PVI-T1 solution. CHG-T1, CHG-T4 and PVI-T4 solutions are statistically comparable for cost and effectiveness. This study is based on the data from the RCT from 11 French intensive care units registered with www.clinicaltrials.gov (NCT01629550).
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- 2018
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10. Diagnostic yield and therapeutic impact of open lung biopsy in the critically ill patient.
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Carole Philipponnet, Lucie Cassagnes, Bruno Pereira, Jean-Louis Kemeny, Mojgan Devouassoux-Shisheboran, Alexandre Lautrette, Claude Guerin, and Bertrand Souweine
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Medicine ,Science - Abstract
Open lung biopsy (OLB) is a rare procedure in intensive care units (ICUs) for therapeutic management of acute respiratory failure (ARF). The purpose of this study was to analyze the diagnostic yield, therapeutic contribution and complications of OLB in ICU patients with ARF of unclear etiology, including acute respiratory distress syndrome (ARDS) and ARDS mimics.Retrospective study conducted in a 10-bed ICU over a 13-year period. Patients undergoing OLB for ARF with undiagnosed infiltrates on CT scan were included. ARDS was defined according to Berlin criteria, and ARDS mimics as a condition looking like ARDS except for the presence of a known cause. OLB was contributive when the OLB findings yielded a specific diagnosis resulting in a change in the patients' treatment or management.Forty six patients were included (sex ratio = 2.5, median and [interquartile range] age = 69 [59-77] years, and admission SAPS II = 42 [33-50]. ARF corresponded to ARDS in 22 patients and to ARDS mimics in 16. OLB yielded 61 diagnoses in 45 patients including diffuse alveolar damage (N = 21), lung fibrosis (N = 18), and organizing pneumonia (N = 11). OLB was contributive in 37 patients (80%), including 13/16 ARDS mimickers. The main contributions of OLB were the introduction or maintenance of steroids (N = 32) and discontinuation of antibiotics (N = 9). In 4 patients OLB resulted directly in the decision to forgo life-sustaining treatment. OLB complications occurred in 16 patients (35%), in one case associated with fatal outcome.OLB can play a useful role in the management of ICU patients with ARF of undetermined origin, including ARDS mimickers. Further studies should be done to identify the groups of ICU patients likely to benefit from the procedure with minimum risk.
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- 2018
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11. Respective impact of implementation of prevention strategies, colonization with multiresistant bacteria and antimicrobial use on the risk of early- and late-onset VAP: An analysis of the OUTCOMEREA network.
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Wafa Ibn Saied, Bertrand Souweine, Maité Garrouste-Orgeas, Stéphane Ruckly, Michael Darmon, Sébastien Bailly, Yves Cohen, Elie Azoulay, Carole Schwebel, Aguila Radjou, Hatem Kallel, Christophe Adrie, Anne-Sylvie Dumenil, Laurent Argaud, Guillaume Marcotte, Samir Jamali, Laurent Papazian, Dany Goldgran-Toledano, Lila Bouadma, Jean-Francois Timsit, and OUTCOMEREA study group
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Medicine ,Science - Abstract
The impact of prevention strategies and risk factors for early-onset (EOP) versus late-onset (LOP) ventilator-associated pneumonia (VAP) are still debated.To evaluate, in a multicenter cohort, the risk factors for EOP and LOP, as the evolution of prevention strategies.7,784 patients with mechanical ventilation (MV) for at least 48 hours were selected into the multicenter prospective OUTCOMEREA database (1997-2016). VAP occurring between the 3rd and 6th day of MV defined EOP, while those occurring after defined LOPs. We used a Fine and Gray subdistribution model to take the successful extubation into account as a competing event.Overall, 1,234 included patients developed VAP (EOP: 445 (36%); LOP: 789 (64%)). Male gender was a risk factor for both EOP and LOP. Factors specifically associated with EOP were admission for respiratory distress, previous colonization with multidrug-resistant Pseudomonas aeruginosa, chest tube and enteral feeding within the first 2 days of MV. Antimicrobials administrated within the first 2 days of MV were all protective of EOP. ICU admission for COPD exacerbation or pneumonia were early risk factors for LOP, while imidazole and vancomycin use within the first 2 days of MV were protective factors. Late risk factors (between the 3rd and the 6th day of MV) were the intra-hospital transport, PAO2-FIO2
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- 2017
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12. Compatibility of Injectable Anticoagulant Agents in Ethanol; In Vitro Antibiofilm Activity and Impact on Polyurethane Catheters of Enoxaparin 400 U/mL in 40% v/v Ethanol.
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Damien Balestrino, Mercédès Quintana, Nicolas Charbonnel, Christiane Forestier, Claire Lartigue, and Bertrand Souweine
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Medicine ,Science - Abstract
BACKGROUND AND OBJECTIVES:Interdialytic lock solutions should maintain catheter patency and prevent catheter infections. We aimed to determine in which conditions injectable anticoagulant agents (IAAs) combined with ethanol are compatible and to assess the antibiofilm activity of the selected combination and its effects on dialysis catheters (DC). METHODS:The solubility and compatibility of unfractionated heparin (UFH), low molecular weight heparins (LMWHs), heparinoids and fondaparinux (50 to 2,500 U/mL) in 30 to 70% ethanol were determined by visual observation. The stability of enoxaparin in ethanol and the ethanol content were assessed by high performance liquid chromatography (HPLC) and titrimetric control, respectively. The bactericidal effect was determined on 24h-old biofilms embedded in silicone-DC. The integrity of polyurethane-DC immersed in anticoagulant-ethanol was assessed by gas chromatography-mass spectrometry (GC-MS) and compared with previously published results. RESULTS:The compatibility of IAAs and ethanol varied according to IAA type and concentration, and ethanol content. UFH in 40% ethanol was not compatible, whatever the UFH concentration used. Established limits of compatibility of enoxaparin, nadroparin, dalteparin and tinzaparin in 40% ethanol were 1350, 575, 307 and 207 U/ml, respectively, and up to 300 U/ml for danaparoid and 1 mg/mL for fondaparinux. Enoxaparin 400 U/mL in 40% ethanol (Enox/Eth) eradicated biofilm after 4 hours of exposure for Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans and after 24 hours for Klebsiella pneumoniae and S. aureus. Aliphatic carbonate and alcohol compounds were released by polyurethane-DC after Enox/Eth exposure, as after 40% ethanol or saline exposure. There was no significant difference between the amounts released after 30 minutes of exposure to Enox/Eth and 15 days to saline. CONCLUSIONS:A 40% ethanol solution can be combined with all IAAs but UFH. Enox/Eth was effective as an anti-biofilm agent with minor impacts on DC integrity and could be a useful interdialytic lock solution.
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- 2016
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13. Spatiotemporal Evolution of Ebola Virus Disease at Sub-National Level during the 2014 West Africa Epidemic: Model Scrutiny and Data Meagreness.
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Eva Santermans, Emmanuel Robesyn, Tapiwa Ganyani, Bertrand Sudre, Christel Faes, Chantal Quinten, Wim Van Bortel, Tom Haber, Thomas Kovac, Frank Van Reeth, Marco Testa, Niel Hens, and Diamantis Plachouras
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Medicine ,Science - Abstract
BACKGROUND:The Ebola outbreak in West Africa has infected at least 27,443 individuals and killed 11,207, based on data until 24 June, 2015, released by the World Health Organization (WHO). This outbreak has been characterised by extensive geographic spread across the affected countries Guinea, Liberia and Sierra Leone, and by localized hotspots within these countries. The rapid recognition and quantitative assessment of localised areas of higher transmission can inform the optimal deployment of public health resources. METHODS:A variety of mathematical models have been used to estimate the evolution of this epidemic, and some have pointed out the importance of the spatial heterogeneity apparent from incidence maps. However, little is known about the district-level transmission. Given that many response decisions are taken at sub-national level, the current study aimed to investigate the spatial heterogeneity by using a different modelling framework, built on publicly available data at district level. Furthermore, we assessed whether this model could quantify the effect of intervention measures and provide predictions at a local level to guide public health action. We used a two-stage modelling approach: a) a flexible spatiotemporal growth model across all affected districts and b) a deterministic SEIR compartmental model per district whenever deemed appropriate. FINDINGS:Our estimates show substantial differences in the evolution of the outbreak in the various regions of Guinea, Liberia and Sierra Leone, illustrating the importance of monitoring the outbreak at district level. We also provide an estimate of the time-dependent district-specific effective reproduction number, as a quantitative measure to compare transmission between different districts and give input for informed decisions on control measures and resource allocation. Prediction and assessing the impact of control measures proved to be difficult without more accurate data. In conclusion, this study provides us a useful tool at district level for public health, and illustrates the importance of collecting and sharing data.
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- 2016
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14. Spatio-Temporal Gene Expression Profiling during In Vivo Early Ovarian Folliculogenesis: Integrated Transcriptomic Study and Molecular Signature of Early Follicular Growth.
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Agnes Bonnet, Bertrand Servin, Philippe Mulsant, and Beatrice Mandon-Pepin
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Medicine ,Science - Abstract
The successful achievement of early ovarian folliculogenesis is important for fertility and reproductive life span. This complex biological process requires the appropriate expression of numerous genes at each developmental stage, in each follicular compartment. Relatively little is known at present about the molecular mechanisms that drive this process, and most gene expression studies have been performed in rodents and without considering the different follicular compartments.We used RNA-seq technology to explore the sheep transcriptome during early ovarian follicular development in the two main compartments: oocytes and granulosa cells. We documented the differential expression of 3,015 genes during this phase and described the gene expression dynamic specific to these compartments. We showed that important steps occurred during primary/secondary transition in sheep. We also described the in vivo molecular course of a number of pathways. In oocytes, these pathways documented the chronology of the acquisition of meiotic competence, migration and cellular organization, while in granulosa cells they concerned adhesion, the formation of cytoplasmic projections and steroid synthesis. This study proposes the involvement in this process of several members of the integrin and BMP families. The expression of genes such as Kruppel-like factor 9 (KLF9) and BMP binding endothelial regulator (BMPER) was highlighted for the first time during early follicular development, and their proteins were also predicted to be involved in gene regulation. Finally, we selected a data set of 24 biomarkers that enabled the discrimination of early follicular stages and thus offer a molecular signature of early follicular growth. This set of biomarkers includes known genes such as SPO11 meiotic protein covalently bound to DSB (SPO11), bone morphogenetic protein 15 (BMP15) and WEE1 homolog 2 (S. pombe)(WEE2) which play critical roles in follicular development but other biomarkers are also likely to play significant roles in this process.To our knowledge, this is the first in vivo spatio-temporal exploration of transcriptomes derived from early follicles in sheep.
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- 2015
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15. Decreased Risk of Ventilator-Associated Pneumonia in Sepsis Due to Intra-Abdominal Infection.
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François Philippart, Gaëlle Bouroche, Jean-François Timsit, Maité Garrouste-Orgeas, Elie Azoulay, Michael Darmon, Christophe Adrie, Bernard Allaouchiche, Claire Ara-Somohano, Stéphane Ruckly, Anne-Sylvie Dumenil, Bertrand Souweine, Dany Goldgran-Toledano, Lila Bouadma, Benoît Misset, and Outcomerea study group
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Medicine ,Science - Abstract
Experimental studies suggest that intra-abdominal infection (IAI) induces biological alterations that may affect the risk of lung infection.To investigate the potential effect of IAI at ICU admission on the subsequent occurrence of ventilator-associated pneumonia (VAP).We used data entered into the French prospective multicenter Outcomerea database in 1997-2011. Consecutive patients who had severe sepsis and/or septic shock at ICU admission and required mechanical ventilation for more than 3 days were included. Patients with acute pancreatitis were not included.Of 2623 database patients meeting the inclusion criteria, 290 (11.1%) had IAI and 2333 (88.9%) had other infections. The IAI group had fewer patients with VAP (56 [19.3%] vs. 806 [34.5%], P
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- 2015
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16. Genome Scan for Selection in Structured Layer Chicken Populations Exploiting Linkage Disequilibrium Information.
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Mahmood Gholami, Christian Reimer, Malena Erbe, Rudolf Preisinger, Annett Weigend, Steffen Weigend, Bertrand Servin, and Henner Simianer
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Medicine ,Science - Abstract
An increasing interest is being placed in the detection of genes, or genomic regions, that have been targeted by selection because identifying signatures of selection can lead to a better understanding of genotype-phenotype relationships. A common strategy for the detection of selection signatures is to compare samples from distinct populations and to search for genomic regions with outstanding genetic differentiation. The aim of this study was to detect selective signatures in layer chicken populations using a recently proposed approach, hapFLK, which exploits linkage disequilibrium information while accounting appropriately for the hierarchical structure of populations. We performed the analysis on 70 individuals from three commercial layer breeds (White Leghorn, White Rock and Rhode Island Red), genotyped for approximately 1 million SNPs. We found a total of 41 and 107 regions with outstanding differentiation or similarity using hapFLK and its single SNP counterpart FLK respectively. Annotation of selection signature regions revealed various genes and QTL corresponding to productions traits, for which layer breeds were selected. A number of the detected genes were associated with growth and carcass traits, including IGF-1R, AGRP and STAT5B. We also annotated an interesting gene associated with the dark brown feather color mutational phenotype in chickens (SOX10). We compared FST, FLK and hapFLK and demonstrated that exploiting linkage disequilibrium information and accounting for hierarchical population structure decreased the false detection rate.
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- 2015
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17. Selection signatures in worldwide sheep populations.
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Maria-Ines Fariello, Bertrand Servin, Gwenola Tosser-Klopp, Rachel Rupp, Carole Moreno, International Sheep Genomics Consortium, Magali San Cristobal, and Simon Boitard
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Medicine ,Science - Abstract
The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep populations, (ii) make use of linkage disequilibrium information and (iii) focus specifically on either recent or older selection signatures. We show that this allows pinpointing several new selection signatures in the sheep genome and distinguishing those related to modern breeding objectives and to earlier post-domestication constraints. The newly identified regions, together with the ones previously identified, reveal the extensive genome response to selection on morphology, color and adaptation to new environments.
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- 2014
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18. Antioxidant and anti-inflammatory activities of extracts from Cassia alata, Eleusine indica, Eremomastax speciosa, Carica papaya and Polyscias fulva medicinal plants collected in Cameroon.
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Bertrand Sagnia, Donatella Fedeli, Rita Casetti, Carla Montesano, Giancarlo Falcioni, and Vittorio Colizzi
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Medicine ,Science - Abstract
BACKGROUND: The vast majority of the population around the world has always used medicinal plants as first source of health care to fight infectious and non infectious diseases. Most of these medicinal plants may have scientific evidence to be considered in general practice. OBJECTIVE: The aim of this work was to investigate the antioxidant capacities and anti-inflammatory activities of ethanol extracts of leaves of Cassia alata, Eleusine indica, Carica papaya, Eremomastax speciosa and the stem bark of Polyscias fulva, collected in Cameroon. METHODS: Chemiluminescence was used to analyze the antioxidant activities of plant extracts against hydrogen peroxide or superoxide anion. Comet assays were used to analyze the protection against antioxidant-induced DNA damage induced in white blood cells after treating with hydrogen peroxide. Flow cytometry was used to measure γδ T cells proliferation and anti-inflammatory activity of γδ T cells and of immature dendritic cells (imDC) in the presence of different concentrations of plant extracts. RESULTS: Ethanol extracts showed strong antioxidant properties against both hydrogen peroxide and superoxide anion. Cassia alata showed the highest antioxidant activity. The effect of plant extracts on γδ T cells and imDC was evidenced by the dose dependent reduction in TNF-α production in the presence of Cassia alata, Carica papaya, Eremomastax speciosa Eleusine indica, and Polyscias fulva. γδ T cells proliferation was affected to the greatest extent by Polyscias fulva. CONCLUSION: These results clearly show the antioxidant capacity and anti-inflammatory activities of plant extracts collected in Cameroon. These properties of leaves and stem bark extracts may contribute to the value for these plants in traditional medicine and in general medical practice.
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- 2014
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19. The C-terminal domain from S. cerevisiae Pat1 displays two conserved regions involved in decapping factor recruitment.
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Zaineb Fourati, Olga Kolesnikova, Régis Back, Jenny Keller, Clément Charenton, Valerio Taverniti, Claudine Gaudon Plesse, Noureddine Lazar, Dominique Durand, Herman van Tilbeurgh, Bertrand Séraphin, and Marc Graille
- Subjects
Medicine ,Science - Abstract
Eukaryotic mRNA decay is a highly regulated process allowing cells to rapidly modulate protein production in response to internal and environmental cues. Mature translatable eukaryotic mRNAs are protected from fast and uncontrolled degradation in the cytoplasm by two cis-acting stability determinants: a methylguanosine (m(7)G) cap and a poly(A) tail at their 5' and 3' extremities, respectively. The hydrolysis of the m(7)G cap structure, known as decapping, is performed by the complex composed of the Dcp2 catalytic subunit and its partner Dcp1. The Dcp1-Dcp2 decapping complex has a low intrinsic activity and requires accessory factors to be fully active. Among these factors, Pat1 is considered to be a central scaffolding protein involved in Dcp2 activation but also in inhibition of translation initiation. Here, we present the structural and functional study of the C-terminal domain from S. cerevisiae Pat1 protein. We have identified two conserved and functionally important regions located at both extremities of the domain. The first region is involved in binding to Lsm1-7 complex. The second patch is specific for fungal proteins and is responsible for Pat1 interaction with Edc3. These observations support the plasticity of the protein interaction network involved in mRNA decay and show that evolution has extended the C-terminal alpha-helical domain from fungal Pat1 proteins to generate a new binding platform for protein partners.
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- 2014
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20. A genome-wide association study points out the causal implication of SOX9 in the sex-reversal phenotype in XX pigs.
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Sarah Rousseau, Nathalie Iannuccelli, Marie-José Mercat, Claire Naylies, Jean-Claude Thouly, Bertrand Servin, Denis Milan, Eric Pailhoux, and Juliette Riquet
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Medicine ,Science - Abstract
Among farm animals, pigs are known to show XX sex-reversal. In such cases the individuals are genetically female but exhibit a hermaphroditism, or a male phenotype. While the frequency of this congenital disease is quite low (less than 1%), the economic losses are significant for pig breeders. These losses result from sterility, urogenital infections and the carcasses being downgraded because of the risk of boar taint. It has been clearly demonstrated that the SRY gene is not involved in most cases of sex-reversal in pigs, and that autosomal recessive mutations remain to be discovered. A whole-genome scan analysis was performed in the French Large-White population to identify candidate genes: 38 families comprising the two non-affected parents and 1 to 11 sex-reversed full-sib piglets were genotyped with the PorcineSNP60 BeadChip. A Transmission Disequilibrium Test revealed a highly significant candidate region on SSC12 (most significant p-value
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- 2013
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21. Adaptation of maize to temperate climates: mid-density genome-wide association genetics and diversity patterns reveal key genomic regions, with a major contribution of the Vgt2 (ZCN8) locus.
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Sophie Bouchet, Bertrand Servin, Pascal Bertin, Delphine Madur, Valérie Combes, Fabrice Dumas, Dominique Brunel, Jacques Laborde, Alain Charcosset, and Stéphane Nicolas
- Subjects
Medicine ,Science - Abstract
The migration of maize from tropical to temperate climates was accompanied by a dramatic evolution in flowering time. To gain insight into the genetic architecture of this adaptive trait, we conducted a 50K SNP-based genome-wide association and diversity investigation on a panel of tropical and temperate American and European representatives. Eighteen genomic regions were associated with flowering time. The number of early alleles cumulated along these regions was highly correlated with flowering time. Polymorphism in the vicinity of the ZCN8 gene, which is the closest maize homologue to Arabidopsis major flowering time (FT) gene, had the strongest effect. This polymorphism is in the vicinity of the causal factor of Vgt2 QTL. Diversity was lower, whereas differentiation and LD were higher for associated loci compared to the rest of the genome, which is consistent with selection acting on flowering time during maize migration. Selection tests also revealed supplementary loci that were highly differentiated among groups and not associated with flowering time in our panel, whereas they were in other linkage-based studies. This suggests that allele fixation led to a lack of statistical power when structure and relatedness were taken into account in a linear mixed model. Complementary designs and analysis methods are necessary to unravel the architecture of complex traits. Based on linkage disequilibrium (LD) estimates corrected for population structure, we concluded that the number of SNPs genotyped should be at least doubled to capture all QTLs contributing to the genetic architecture of polygenic traits in this panel. These results show that maize flowering time is controlled by numerous QTLs of small additive effect and that strong polygenic selection occurred under cool climatic conditions. They should contribute to more efficient genomic predictions of flowering time and facilitate the dissemination of diverse maize genetic resources under a wide range of environments.
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- 2013
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22. Distinct CD4+ CD8+ double-positive T cells in the blood and liver of patients during chronic hepatitis B and C.
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Michelina Nascimbeni, Stanislas Pol, and Bertrand Saunier
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Medicine ,Science - Abstract
CD4(+) and CD8(+) T cells, the main effectors of adaptive cellular immune responses, differentiate from immature, non-functional CD4(+)CD8(+) double-positive T (DPT) cells in the thymus. Increased proportions of circulating DPT lymphocytes have been observed during acute viral infections; in chronic viral diseases, the role and repartition of extra-thymic DPT cells remain largely uncharacterized. We performed a phenotypic analysis of DPT cells in blood and liver from patients chronically infected by hepatitis C (HCV) or B (HBV) viruses. The highest percentages of DPT cells, predominantly CD4(high)CD8(low), were observed in patients infected by HCV, while HBV-infected patients mostly displayed CD4(low)CD8(high) and CD4(high)CD8(high) DPT cells. All proportions of DPT cells were higher in liver than in blood with, for each subpopulation referred to above, a correlation between their frequencies in these two compartments. In HCV patients, intra-hepatic DPT cells displayed more heterogeneous activation, differentiation and memory phenotypes than in the blood; most of them expressed CD1a, a marker of T cell development in the thymus. Ex vivo, the inoculation of liver slices with HCV produced in cell culture was accompanied by a disappearance of CD8(high) cells, suggesting a direct effect of the virus on the phenotype of DPT cells in the liver. Our results suggest that, in half of the patients, chronic HCV infection promotes the production of DPT cells, perhaps by their re-induction in the thymus and selection in the liver.
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- 2011
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23. Reconciliation and evolution of Penicillium rubens genome-scale metabolic networks-What about specialised metabolism?
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Nègre D, Larhlimi A, and Bertrand S
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- Metabolic Networks and Pathways genetics, Chromosome Mapping, Genomics, Penicillium genetics, Biological Products
- Abstract
In recent years, genome sequencing of filamentous fungi has revealed a high proportion of specialised metabolites with growing pharmaceutical interest. However, detecting such metabolites through in silico genome analysis does not necessarily guarantee their expression under laboratory conditions. However, one plausible strategy for enabling their production lies in modifying the growth conditions. Devising a comprehensive experimental design testing in different culture environments is time-consuming and expensive. Therefore, using in silico modelling as a preliminary step, such as Genome-Scale Metabolic Network (GSMN), represents a promising approach to predicting and understanding the observed specialised metabolite production in a given organism. To address these questions, we reconstructed a new high-quality GSMN for the Penicillium rubens Wisconsin 54-1255 strain, a commonly used model organism. Our reconstruction, iPrub22, adheres to current convention standards and quality criteria, incorporating updated functional annotations, orthology searches with different GSMN templates, data from previous reconstructions, and manual curation steps targeting primary and specialised metabolites. With a MEMOTE score of 74% and a metabolic coverage of 45%, iPrub22 includes 5,192 unique metabolites interconnected by 5,919 reactions, of which 5,033 are supported by at least one genomic sequence. Of the metabolites present in iPrub22, 13% are categorised as belonging to specialised metabolism. While our high-quality GSMN provides a valuable resource for investigating known phenotypes expressed in P. rubens, our analysis identifies bottlenecks related, in particular, to the definition of what is a specialised metabolite, which requires consensus within the scientific community. It also points out the necessity of accessible, standardised and exhaustive databases of specialised metabolites. These questions must be addressed to fully unlock the potential of natural product production in P. rubens and other filamentous fungi. Our work represents a foundational step towards the objective of rationalising the production of natural products through GSMN modelling., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Nègre et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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24. Using canavanine resistance to measure mutation rates in Schizosaccharomyces pombe.
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Pai CC, Heitzer E, Bertrand S, Toumazou S, Humphrey TC, and Kearsey SE
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- Canavanine pharmacology, Canavanine metabolism, Mutation Rate, Mutation, Arginine metabolism, Arrestins metabolism, Schizosaccharomyces genetics, Schizosaccharomyces metabolism, Schizosaccharomyces pombe Proteins metabolism
- Abstract
We constructed a panel of S. pombe strains expressing DNA polymerase ε variants associated with cancer, specifically POLES297F, POLEV411L, POLEL424V, POLES459F, and used these to compare mutation rates determined by canavanine resistance with other selective methods. Canavanine-resistance mutation rates are broadly similar to those seen with reversion of the ade-485 mutation to adenine prototrophy, but lower than 5-fluoroorotic acid (FOA)-resistance rates (inactivation of ura4+ or ura5+ genes). Inactivation of several genes has been associated with canavanine resistance in S. pombe but surprisingly whole genome sequencing showed that 8/8 spontaneous canavanine-resistant mutants have an R175C mutation in the any1/arn1 gene. This gene encodes an α-arrestin-like protein involved in mediating Pub1 ubiquitylation of target proteins, and the phenotypic resistance to canavanine by this single mutation is similar to that shown by the original "can1-1" strain, which also has the any1R175C mutation. Some of the spontaneous mutants have additional mutations in arginine transporters, suggesting that this may marginally increase resistance to canavanine. The any1R175C strain showed internalisation of the Cat1 arginine transporter as previously reported, explaining the canavanine-resistance phenotype., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Pai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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25. Exploring tissue morphodynamics using the photoconvertible Kaede protein in amphioxus embryos.
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Meister L, Escriva H, and Bertrand S
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- Animals, Green Fluorescent Proteins metabolism, Luminescent Proteins metabolism, Ultraviolet Rays, Anthozoa metabolism, Lancelets
- Abstract
Photoconvertible proteins are powerful tools widely used in cellular biology to study cell dynamics and organelles. Over the past decade, photoconvertible proteins have also been used for developmental biology applications to analyze cell lineage and cell fate during embryonic development. One of these photoconvertible proteins called Kaede, from the stony coral Trachyphyllia geoffroyi, undergoes irreversible photoconversion from green to red fluorescence when illuminated with UV light. Undertaking a cell tracing approach using photoconvertible proteins can be challenging when using unconventional animal models. In this protocol, we describe the use of Kaede to track specific cells during embryogenesis of the cephalochordate Branchiostoma lanceolatum. This protocol can be adapted to other unconventional models, especially marine animals., Competing Interests: The authors have declared that no competing interests exist.
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- 2022
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26. Assessing the progress on the implementation of policy and legislation actions to address the Non-Communicable Diseases crisis in the Pacific.
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Win Tin ST, Kubuabola I, Snowdon W, Cash HL, Na'ati E, Waqa GD, Moadsiri A, Bertrand S, and Ravuvu A
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- Child, Female, Health Policy, Humans, Marketing, Pacific Islands epidemiology, Policy Making, Noncommunicable Diseases epidemiology, Noncommunicable Diseases prevention & control
- Abstract
Aim: To assess the progress on the implementation of Non-Communicable Diseases (NCD) related policies and legislations in the Pacific Island Countries and Territories (PICTs)., Materials and Methods: The Pacific Monitoring Alliance for NCD Action (MANA) Dashboard was used to assess the progress on the implementation. The MANA Dashboard includes 31 indicators across four different domains such as leadership and governance; preventative policies and legislations; health system response programs; and monitoring This progress assessment was conducted between 2019 and 2020 for all 21 PICTs. The data were analyzed and compared with the baseline status (2018) report and presented across four different domains of the MANA dashboard., Results: This progress assessment found that PICTs overall have made advancements in a number of areas, particularly the establishment of a national multi-sectoral NCD taskforce; implementation of referenced approaches to restrict trans-fat in the food supply in national documents; and fiscal measures to affect access and availability to less healthy foods and drinks. However, the strengths of actions varied across PICTs, and most are categorised as low strengths. Measures which had the most limited progress in implementation include policy and legislation that restrict alcohol advertising; tobacco industry interference; marketing of foods and non-alcoholic beverages to children; and marketing for breast milk substitutes., Conclusions: This progress assessment further highlights that while PICTs continue to make progress, NCD policy and legislation gaps still exist, both in terms of weaknesses of existing measures and areas that have had little attention to-date. These require urgent actions to scale up NCD related policies and legislation at regional and national level., Competing Interests: The authors have declared that no competing interests exist.
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- 2022
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27. "Too Big To Ignore": A feasibility analysis of detecting fishing events in Gabonese small-scale fisheries.
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Cardiec F, Bertrand S, Witt MJ, Metcalfe K, Godley BJ, McClellan C, Vilela R, Parnell RJ, and le Loc'h F
- Subjects
- Feasibility Studies, Food Supply, Gabon, Geographic Information Systems, Humans, Markov Chains, Fisheries
- Abstract
In many developing countries, small-scale fisheries provide employment and important food security for local populations. To support resource management, the description of the spatiotemporal extent of fisheries is necessary, but often poorly understood due to the diffuse nature of effort, operated from numerous small wooden vessels. Here, in Gabon, Central Africa, we applied Hidden Markov Models to detect fishing patterns in seven different fisheries (with different gears) from GPS data. Models were compared to information collected by on-board observers (7 trips) and, at a larger scale, to a visual interpretation method (99 trips). Models utilizing different sampling resolutions of GPS acquisition were also tested. Model prediction accuracy was high with GPS data sampling rates up to three minutes apart. The minor loss of accuracy linked to model classification is largely compensated by the savings in time required for analysis, especially in a context of nations or organizations with limited resources. This method could be applied to larger datasets at a national or international scale to identify and more adequately manage fishing effort., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
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28. Asymmetron lucayanum: How many species are valid?
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Subirana L, Farstey V, Bertrand S, and Escriva H
- Subjects
- Animals, Biological Evolution, Cephalochordata genetics, Cephalochordata growth & development, DNA, Mitochondrial analysis, DNA, Mitochondrial genetics, Electron Transport Complex IV genetics, Genetic Speciation, Genome, Mitochondrial, Larva, Species Specificity, Cephalochordata classification, Phylogeny
- Abstract
The cephalochordates amphioxus or lancelets are benthic marine animals representing the earliest divergent evolutionary lineage within chordates. Although amphioxus are present in most of the world's tropical and temperate oceans, only about thirty different species grouped into three different genera, Branchiostoma, Epigonichthys and Asymmetron have been described. In the genus Asymmetron, only two species have been characterized, although for one of them, A. lucayanum, several cryptic lineages exist. In this work we have sequenced and analyzed the mitogenome of an A. lucayanum population previously described in the Red Sea. The phylogenetic study using this complete mitogenome as well as the analysis of COI gene sequences of several individuals of this Red Sea population show that the Red Sea population is a new cryptic species. We propose to call this new species Asymmetron rubrum., Competing Interests: The authors have declared that no competing interests exist
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- 2020
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29. Correction: Multi Locus Variable-Number Tandem Repeat (MLVA) Typing Tools Improved the Surveillance of Salmonella Enteritidis: A 6 Years Retrospective Study.
- Author
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Bertrand S, De Lamine de Bex G, Wildemauwe C, Lunguya O, Phoba MF, Ley B, Jacobs J, Vanhoof R, and Mattheus W
- Abstract
[This corrects the article DOI: 10.1371/journal.pone.0117950.].
- Published
- 2018
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30. Comparison of SNP-based subtyping workflows for bacterial isolates using WGS data, applied to Salmonella enterica serotype Typhimurium and serotype 1,4,[5],12:i:.
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Saltykova A, Wuyts V, Mattheus W, Bertrand S, Roosens NHC, Marchal K, and De Keersmaecker SCJ
- Subjects
- Genes, Bacterial, Phylogeny, Salmonella enterica classification, Salmonella typhimurium classification, Polymorphism, Single Nucleotide, Salmonella enterica genetics, Salmonella typhimurium genetics, Whole Genome Sequencing
- Abstract
Whole genome sequencing represents a promising new technology for subtyping of bacterial pathogens. Besides the technological advances which have pushed the approach forward, the last years have been marked by considerable evolution of the whole genome sequencing data analysis methods. Prior to application of the technology as a routine epidemiological typing tool, however, reliable and efficient data analysis strategies need to be identified among the wide variety of the emerged methodologies. In this work, we have compared three existing SNP-based subtyping workflows using a benchmark dataset of 32 Salmonella enterica subsp. enterica serovar Typhimurium and serovar 1,4,[5],12:i:- isolates including five isolates from a confirmed outbreak and three isolates obtained from the same patient at different time points. The analysis was carried out using the original (high-coverage) and a down-sampled (low-coverage) datasets and two different reference genomes. All three tested workflows, namely CSI Phylogeny-based workflow, CFSAN-based workflow and PHEnix-based workflow, were able to correctly group the confirmed outbreak isolates and isolates from the same patient with all combinations of reference genomes and datasets. However, the workflows differed strongly with respect to the SNP distances between isolates and sensitivity towards sequencing coverage, which could be linked to the specific data analysis strategies used therein. To demonstrate the effect of particular data analysis steps, several modifications of the existing workflows were also tested. This allowed us to propose data analysis schemes most suitable for routine SNP-based subtyping applied to S. Typhimurium and S. 1,4,[5],12:i:-. Results presented in this study illustrate the importance of using correct data analysis strategies and to define benchmark and fine-tune parameters applied within routine data analysis pipelines to obtain optimal results.
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- 2018
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31. Pharmacological characterisation of S 47445, a novel positive allosteric modulator of AMPA receptors.
- Author
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Bretin S, Louis C, Seguin L, Wagner S, Thomas JY, Challal S, Rogez N, Albinet K, Iop F, Villain N, Bertrand S, Krazem A, Bérachochéa D, Billiald S, Tordjman C, Cordi A, Bertrand D, Lestage P, and Danober L
- Subjects
- Animals, Binding Sites, Cell Line, Cells, Cultured, Glutamic Acid pharmacology, Humans, Locomotion drug effects, Male, Maze Learning drug effects, Mice, Neurons drug effects, Neurons metabolism, Oocytes drug effects, Oocytes metabolism, Patch-Clamp Techniques, Rats, Receptors, AMPA chemistry, Xenopus, Allosteric Regulation drug effects, Receptors, AMPA agonists
- Abstract
S 47445 is a novel positive allosteric modulator of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors (AMPA-PAM). S 47445 enhanced glutamate's action at AMPA receptors on human and rat receptors and was inactive at NMDA and kainate receptors. Potentiation did not differ among the different AMPA receptors subtypes (GluA1/2/4 flip and flop variants) (EC50 between 2.5-5.4 μM), except a higher EC50 value for GluA4 flop (0.7 μM) and a greater amount of potentiation on GluA1 flop. A low concentration of S 47445 (0.1 μM) decreased receptor response decay time of GluA1flop/GluA2flip AMPA receptors and increased the sensitivity to glutamate. Furthermore, S 47445 (0.1 and 0.3 μM) in presence of repetitive glutamate pulses induced a progressive potentiation of the glutamate-evoked currents from the second pulse of glutamate confirming a rapid-enhancing effect of S 47445 at low concentrations. The potentiating effect of S 47445 (1 μM) was concentration-dependently reversed by the selective AMPA receptor antagonist GYKI52466 demonstrating the selective modulatory effect of S 47445 on AMPA receptors. Using an AMPA-kainate chimera approach, it was confirmed that S 47445 binds to the common binding pocket of AMPA-PAMs. S 47445 did not demonstrate neurotoxic effect against glutamate-mediated excitotoxicity in vitro, in contrast significantly protected rat cortical neurons at 10 μM. S 47445 was shown to improve both episodic and spatial working memory in adult rodents at 0.3 mg/kg, as measured in the natural forgetting condition of object recognition and T-maze tasks. Finally, no deleterious effect on spontaneous locomotion and general behavior was observed up to 1000 mg/kg of S 47445 given acutely in rodents, neither occurrence of convulsion or tremors. Collectively, these results indicate that S 47445 is a potent and selective AMPA-PAM presenting procognitive and potential neuroprotective properties. This drug is currently evaluated in clinical phase 2 studies in Alzheimer's disease and in Major Depressive Disorder.
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- 2017
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32. Population-based incidence, seasonality and serotype distribution of invasive salmonellosis among children in Nanoro, rural Burkina Faso.
- Author
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Guiraud I, Post A, Diallo SN, Lompo P, Maltha J, Thriemer K, Tahita CM, Ley B, Derra K, Bottieau E, Kazienga A, Schurmans C, Ravinetto R, Rouamba E, Van Griensven J, Bertrand S, Tinto H, and Jacobs J
- Subjects
- Burkina Faso epidemiology, Catchment Area, Health, Child, Child, Preschool, Demography, Female, Geography, Humans, Incidence, Infant, Malaria complications, Malaria epidemiology, Male, Salmonella isolation & purification, Seasons, Salmonella Infections blood, Salmonella Infections epidemiology, Serotyping methods
- Abstract
Background: Bloodstream infections (BSI) caused by Salmonella Typhi and invasive non-Typhoidal Salmonella (iNTS) frequently affect children living in rural sub-Saharan Africa but data about incidence and serotype distribution are rare., Objective: The present study assessed the population-based incidence of Salmonella BSI and severe malaria in a Health and Demographic Surveillance System in a rural area with seasonal malaria transmission in Nanoro, Burkina Faso., Methods: Children between 2 months-15 years old with severe febrile illness were enrolled during a one-year surveillance period (May 2013-May 2014). Thick blood films and blood cultures were sampled and processed upon admission. Population-based incidences were corrected for non-referral, health seeking behavior, non-inclusion and blood culture sensitivity. Adjusted incidence rates were expressed per 100,000 person-years of observations (PYO)., Results: Among children < 5 years old, incidence rates for iNTS, Salmonella Typhi and severe malaria per 100,000 PYO were 4,138 (95% Confidence Interval (CI): 3,740-4,572), 224 (95% CI: 138-340) and 2,866 (95% CI: 2,538-3,233) respectively. Among those aged 5-15 years, corresponding incidence rates were 25 (95% CI: 8-60), 273 (95% CI: 203-355) and 135 (95% CI: 87-195) respectively. Most iNTS occurred during the peak of the rainy season and in parallel with the increase of Plasmodium falciparum malaria; for Salmonella Typhi no clear seasonal pattern was observed. Salmonella Typhi and iNTS accounted for 13.3% and 55.8% of all 118 BSI episodes; 71.6% of iNTS (48/67) isolates were Salmonella enterica serovar Typhimurium and 25.4% (17/67) Salmonella enterica serovar Enteritidis; there was no apparent geographical clustering., Conclusion: The present findings from rural West-Africa confirm high incidences of Salmonella Typhi and iNTS, the latter with a seasonal and Plasmodium falciparum-related pattern. It urges prioritization of the development and implementation of Salmonella Typhi as well as iNTS vaccines in this setting.
- Published
- 2017
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33. Prevalence and Diversity of Salmonella Serotypes in Ecuadorian Broilers at Slaughter Age.
- Author
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Vinueza-Burgos C, Cevallos M, Ron-Garrido L, Bertrand S, and De Zutter L
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Chickens microbiology, Drug Resistance, Bacterial, Ecuador epidemiology, Electrophoresis, Gel, Pulsed-Field veterinary, Genotype, Microbial Sensitivity Tests veterinary, Poultry Diseases microbiology, Prevalence, Salmonella drug effects, Salmonella Infections, Animal microbiology, Salmonella enteritidis genetics, Serotyping, Poultry Diseases epidemiology, Salmonella genetics, Salmonella Infections, Animal epidemiology
- Abstract
Salmonella is frequently found in poultry and represent an important source for human gastrointestinal infections worldwide. The aim of this study was to investigate the prevalence, genotypes and antimicrobial resistance of Salmonella serotypes in broilers from Ecuador. Caeca content from 388 at random selected broiler batches were collected in 6 slaughterhouses during 1 year and analyzed by the ISO 6579/Amd1 protocol for the isolation for Salmonella. Isolates were serotyped and genotypic variation was acceded by pulsed field gel electrophoresis. MIC values for sulfamethoxazole, gentamicin, ciprofloxacin, ampicillin, cefotaxime, ceftazidime, tetracycline, streptomycin, trimethropim, chloramphenicol, colistin, florfenicol, kanamycin and nalidixic acid were obtained. Presence of blaCTX-M, blaTEM, blaSHV and blaCMY; and mcr-1 plasmid genes was investigated in resistant strains to cefotaxime and colistin respectively. Prevalence at batch level was 16.0%. The most common serotype was S. Infantis (83.9%) followed by S. Enteritidis (14.5%) and S. Corvallis (1.6%). The pulsed field gel electrophoresis analysis showed that S. Corvallis, S. Enteritidis and S. Infantis isolates belonged to 1, 2 and 12 genotypes respectively. S. Infantis isolates showed high resistance rates to 12 antibiotics ranging from 57.7% (kanamycin) up to 98.1% (nalidixic acid and sulfamethoxazole). All S. Enteritidis isolates showed resistance to colistin. High multiresistant patterns were found for all the serotypes. The blaCTX-M gene was present in 33 S. Infantis isolates while mcr-1 was negative in 10 colistin resistant isolates. This study provides the first set of scientific data on prevalence and multidrug-resistant Salmonella coming from commercial poultry in Ecuador.
- Published
- 2016
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34. Molecular Analysis of Rising Fluoroquinolone Resistance in Belgian Non-Invasive Streptococcus pneumoniae Isolates (1995-2014).
- Author
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Ceyssens PJ, Van Bambeke F, Mattheus W, Bertrand S, Fux F, Van Bossuyt E, Damée S, Nyssen HJ, De Craeye S, Verhaegen J, Tulkens PM, and Vanhoof R
- Subjects
- Amino Acid Substitution, Belgium epidemiology, Drug Resistance, Bacterial drug effects, Female, Humans, Longitudinal Studies, Male, Pneumococcal Infections drug therapy, Pneumococcal Infections epidemiology, Pneumococcal Infections genetics, ATP-Binding Cassette Transporters genetics, Bacterial Proteins genetics, DNA Gyrase genetics, Drug Resistance, Bacterial genetics, Fluoroquinolones pharmacology, Mutation, Missense, Streptococcus pneumoniae genetics, Streptococcus pneumoniae isolation & purification
- Abstract
We present the results of a longitudinal surveillance study (1995-2014) on fluoroquinolone resistance (FQ-R) among Belgian non-invasive Streptococcus pneumoniae isolates (n = 5,602). For many years, the switch to respiratory fluoroquinolones for the treatment of (a)typical pneumonia had no impact on FQ-R levels. However, since 2011 we observed a significant decrease in susceptibility towards ciprofloxacin, ofloxacin and levofloxacin with peaks of 9.0%, 6.6% and 3.1% resistant isolates, respectively. Resistance to moxifloxacin arised sporadically, and remained <1% throughout the entire study period. We observed classical topoisomerase mutations in gyrA (n = 25), parC (n = 46) and parE (n = 3) in varying combinations, arguing against clonal expansion of FQ-R. The impact of recombination with co-habiting commensal streptococci on FQ-R remains marginal (10.4%). Notably, we observed that a rare combination of DNA Gyrase mutations (GyrA_S81L/GyrB_P454S) suffices for high-level moxifloxacin resistance, contrasting current model. Interestingly, 85/422 pneumococcal strains display MICCIP values which were lowered by at least four dilutions by reserpine, pointing at involvement of efflux pumps in FQ-R. In contrast to susceptible strains, isolates resistant to ciprofloxacin significantly overexpressed the ABC pump PatAB in comparison to reference strain S. pneumoniae ATCC 49619, but this could only be linked to disruptive terminator mutations in a fraction of these. Conversely, no difference in expression of the Major Facilitator PmrA, unaffected by reserpine, was noted between susceptible and resistant S. pneumoniae strains. Finally, we observed that four isolates displayed intermediate to high-level ciprofloxacin resistance without any known molecular resistance mechanism. Focusing future molecular studies on these isolates, which are also commonly found in other studies, might greatly assist in the battle against rising pneumococcal drug resistance.
- Published
- 2016
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35. Changes in Meningococcal Strains in the Era of a Serogroup C Vaccination Campaign: Trends and Evolution in Belgium during the Period 1997-2012.
- Author
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Mattheus W, Hanquet G, Collard JM, Vanhoof R, and Bertrand S
- Subjects
- Adolescent, Adult, Belgium epidemiology, Child, Child, Preschool, DNA, Bacterial genetics, Female, Humans, Infant, Male, Meningococcal Infections microbiology, Meningococcal Infections mortality, Meningococcal Infections prevention & control, Multilocus Sequence Typing, Neisseria meningitidis, Serogroup C isolation & purification, Phenotype, Prognosis, Serogroup, Survival Rate, Time Factors, Young Adult, Biological Evolution, Meningococcal Infections epidemiology, Meningococcal Vaccines therapeutic use, Neisseria meningitidis, Serogroup C classification, Neisseria meningitidis, Serogroup C genetics, Vaccination mortality
- Abstract
Background: Invasive meningococcal disease (IMD) is a major cause of bacterial meningitides and septicaemia. This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012., Methods: The results are based on microbiological and molecular laboratory surveillance of 2997 clinical isolates of N. meningitides received by the Belgian Meningococcal Reference Centre (BMRC) over the period 1997-2012., Results: Serogroup B has always been a major cause of meningococcal disease in Belgium, with P3.4 as most frequent serotype till 2008, while an increase in non-serotypable strains has been observed in the last few years. Clonal complexes cc-41/44 and cc-269 are most frequently observed in serogroup B strains. In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex). The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%). Since 2008 a difference in incidence of serogroup C was observed in Flanders (0-0.1/100,000) versus Wallonia (0.1-0.3/100,000)., Conclusion: This study showed the change in epidemiology and strain population over a 16 years period spanning an exhaustive vaccination campaign and highlights the influence of regional vaccination policies with different cohorts sizes on short and long-term IMD incidences.
- Published
- 2015
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36. Evolution of the Role of RA and FGF Signals in the Control of Somitogenesis in Chordates.
- Author
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Bertrand S, Aldea D, Oulion S, Subirana L, de Lera AR, Somorjai I, and Escriva H
- Subjects
- Animals, Receptors, Notch metabolism, Wnt Signaling Pathway drug effects, Epidermal Growth Factor metabolism, Lancelets embryology, Somites embryology, Tretinoin pharmacology, Wnt Signaling Pathway physiology
- Abstract
During vertebrate development, the paraxial mesoderm becomes segmented, forming somites that will give rise to dermis, axial skeleton and skeletal muscles. Although recently challenged, the "clock and wavefront" model for somitogenesis explains how interactions between several cell-cell communication pathways, including the FGF, RA, Wnt and Notch signals, control the formation of these bilateral symmetric blocks. In the cephalochordate amphioxus, which belongs to the chordate phylum together with tunicates and vertebrates, the dorsal paraxial mesendoderm also periodically forms somites, although this process is asymmetric and extends along the whole body. It has been previously shown that the formation of the most anterior somites in amphioxus is dependent upon FGF signalling. However, the signals controlling somitogenesis during posterior elongation in amphioxus are still unknown. Here we show that, contrary to vertebrates, RA and FGF signals act independently during posterior elongation and that they are not mandatory for posterior somites to form. Moreover, we show that RA is not able to buffer the left/right asymmetry machinery that is controlled through the asymmetric expression of Nodal pathway actors. Our results give new insights into the evolution of the somitogenesis process in chordates. They suggest that RA and FGF pathways have acquired specific functions in the control of somitogenesis in vertebrates. We propose that the "clock and wavefront" system was selected specifically in vertebrates in parallel to the development of more complex somite-derived structures but that it was not required for somitogenesis in the ancestor of chordates.
- Published
- 2015
- Full Text
- View/download PDF
37. Generalized Pareto for Pattern-Oriented Random Walk Modelling of Organisms' Movements.
- Author
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Bertrand S, Joo R, and Fablet R
- Subjects
- Animal Distribution, Animals, Diffusion, Ecosystem, Humans, Motion, Ships, Stochastic Processes, Models, Statistical, Movement, Pattern Recognition, Automated
- Abstract
How organisms move and disperse is crucial to understand how population dynamics relates to the spatial heterogeneity of the environment. Random walk (RW) models are typical tools to describe movement patterns. Whether Lévy or alternative RW better describes forager movements is keenly debated. We get around this issue using the Generalized Pareto Distribution (GPD). GPD includes as specific cases Normal, exponential and power law distributions, which underlie Brownian, Poisson-like and Lévy walks respectively. Whereas previous studies typically confronted a limited set of candidate models, GPD lets the most likely RW model emerge from the data. We illustrate the wide applicability of the method using GPS-tracked seabird foraging movements and fishing vessel movements tracked by Vessel Monitoring System (VMS), both collected in the Peruvian pelagic ecosystem. The two parameters from the fitted GPD, a scale and a shape parameter, provide a synoptic characterization of the observed movement in terms of characteristic scale and diffusive property. They reveal and quantify the variability, among species and individuals, of the spatial strategies selected by predators foraging on a common prey field. The GPD parameters constitute relevant metrics for (1) providing a synthetic and pattern-oriented description of movement, (2) using top predators as ecosystem indicators and (3) studying the variability of spatial behaviour among species or among individuals with different personalities.
- Published
- 2015
- Full Text
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38. Multi locus variable-number tandem repeat (MLVA) typing tools improved the surveillance of Salmonella enteritidis: a 6 years retrospective study.
- Author
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Bertrand S, De Lamine de Bex G, Wildemauwe C, Lunguya O, Phoba MF, Ley B, Jacobs J, Vanhoof R, and Mattheus W
- Subjects
- Anti-Bacterial Agents pharmacology, Disease Outbreaks, Humans, Retrospective Studies, Salmonella Infections epidemiology, Salmonella enteritidis drug effects, Salmonella enteritidis isolation & purification, Bacterial Typing Techniques methods, Genetic Loci genetics, Minisatellite Repeats, Public Health Surveillance methods, Salmonella enteritidis classification, Salmonella enteritidis genetics
- Abstract
Surveillance of Salmonella enterica subsp. enterica serovar Enteritidis is generally considered to benefit from molecular techniques like multiple-locus variable-number of tandem repeats analysis (MLVA), which allow early detection and confinement of outbreaks. Here, a surveillance study, including phage typing, antimicrobial susceptibility testing and MLVA on 1,535 S. Enteritidis isolates collected between 2007 and 2012, was used to evaluate the added value of MLVA for public health surveillance in Belgium. Phage types PT4, PT8, PT21, PT1, PT6, PT14b, PT28 and PT13 dominate the Belgian S. Enteritidis population. The isolates of S. Enteritidis were most frequently susceptible to all antibiotics tested. 172 different MLVA profiles were detected, of which 9 frequent profiles included 67.2% of the S. Enteritidis population. During a serial passage experiment on selected isolates to investigate the in vitro stability of the 5 MLVA loci, no variations over time were observed indicating that the MLVA profiles were stable. The MLVA profile of isolates originating from different outbreaks in the Democratic Republic of the Congo (DRC) between 2010 and 2011 were distinct from any of the MLVA profiles found in Belgian isolates throughout the six year observational period and demonstrates that MLVA improves public health surveillance of S. Enteritidis. However, MLVA should be complemented with other subtyping methods when investigating outbreaks is caused by the most common MLVA profile.
- Published
- 2015
- Full Text
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39. Niches, population structure and genome reduction in Ochrobactrum intermedium: clues to technology-driven emergence of pathogens.
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Aujoulat F, Romano-Bertrand S, Masnou A, Marchandin H, and Jumas-Bilak E
- Subjects
- Base Sequence, Cluster Analysis, DNA, Bacterial genetics, Databases, Genetic, Electrophoresis, Gel, Pulsed-Field, Humans, Likelihood Functions, Multilocus Sequence Typing, Ochrobactrum classification, Ochrobactrum physiology, Phylogeny, Ecosystem, Evolution, Molecular, Genome, Bacterial genetics, Ochrobactrum genetics, Technology
- Abstract
Ochrobactrum intermedium is considered as an emerging human environmental opportunistic pathogen with mild virulence. The distribution of isolates and sequences described in literature and databases showed frequent association with human beings and polluted environments. As population structures are related to bacterial lifestyles, we investigated by multi-locus approach the genetic structure of a population of 65 isolates representative of the known natural distribution of O. intermedium. The population was further surveyed for genome dynamics using pulsed-field gel electrophoresis and genomics. The population displayed a clonal epidemic structure with events of recombination that occurred mainly in clonal complexes. Concerning biogeography, clones were shared by human and environments and were both cosmopolitan and local. The main cosmopolitan clone was genetically and genomically stable, and grouped isolates that all harbored an atypical insertion in the rrs. Ubiquitism and stability of this major clone suggested a clonal succes in a particular niche. Events of genomic reduction were detected in the population and the deleted genomic content was described for one isolate. O. intermedium displayed allopatric characters associated to a tendancy of genome reduction suggesting a specialization process. Considering its relatedness with Brucella, this specialization might be a commitment toward pathogenic life-style that could be driven by technological selective pressure related medical and industrial technologies.
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- 2014
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40. MLVA as a tool for public health surveillance of human Salmonella Typhimurium: prospective study in Belgium and evaluation of MLVA loci stability.
- Author
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Wuyts V, Mattheus W, De Laminne de Bex G, Wildemauwe C, Roosens NH, Marchal K, De Keersmaecker SC, and Bertrand S
- Subjects
- Belgium epidemiology, Humans, Prospective Studies, Salmonella Infections microbiology, Salmonella typhimurium genetics, Bacterial Typing Techniques methods, Disease Outbreaks prevention & control, Minisatellite Repeats genetics, Public Health Surveillance, Salmonella Infections epidemiology, Salmonella typhimurium isolation & purification
- Abstract
Surveillance of Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) is generally considered to benefit from molecular techniques like multiple-locus variable-number of tandem repeats analysis (MLVA), which allow earlier detection and confinement of outbreaks. Here, a surveillance study, including phage typing, antimicrobial susceptibility testing and the in Europe most commonly used 5-loci MLVA on 1,420 S. Typhimurium isolates collected between 2010 and 2012 in Belgium, was used to evaluate the added value of MLVA for public health surveillance. Phage types DT193, DT195, DT120, DT104, DT12 and U302 dominate the Belgian S. Typhimurium population. A combined resistance to ampicillin, streptomycin, sulphonamides and tetracycline (ASSuT) with or without additional resistances was observed for 42.5% of the isolates. 414 different MLVA profiles were detected, of which 14 frequent profiles included 44.4% of the S. Typhimurium population. During a serial passage experiment on selected isolates to investigate the in vitro stability of the 5 MLVA loci, variations over time were observed for loci STTR6, STTR10, STTR5 and STTR9. This study demonstrates that MLVA improves public health surveillance of S. Typhimurium. However, the 5-loci MLVA should be complemented with other subtyping methods for investigation of possible outbreaks with frequent MLVA profiles. Also, variability in these MLVA loci should be taken into account when investigating extended outbreaks and studying dynamics over longer periods.
- Published
- 2013
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- View/download PDF
41. Hidden Markov models: the best models for forager movements?
- Author
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Joo R, Bertrand S, Tam J, and Fablet R
- Subjects
- Computer Simulation, Fisheries, Humans, Motor Activity, Neural Networks, Computer, Peru, Ships, Support Vector Machine, Travel, Appetitive Behavior, Markov Chains, Models, Biological
- Abstract
One major challenge in the emerging field of movement ecology is the inference of behavioural modes from movement patterns. This has been mainly addressed through Hidden Markov models (HMMs). We propose here to evaluate two sets of alternative and state-of-the-art modelling approaches. First, we consider hidden semi-Markov models (HSMMs). They may better represent the behavioural dynamics of foragers since they explicitly model the duration of the behavioural modes. Second, we consider discriminative models which state the inference of behavioural modes as a classification issue, and may take better advantage of multivariate and non linear combinations of movement pattern descriptors. For this work, we use a dataset of >200 trips from human foragers, Peruvian fishermen targeting anchovy. Their movements were recorded through a Vessel Monitoring System (∼1 record per hour), while their behavioural modes (fishing, searching and cruising) were reported by on-board observers. We compare the efficiency of hidden Markov, hidden semi-Markov, and three discriminative models (random forests, artificial neural networks and support vector machines) for inferring the fishermen behavioural modes, using a cross-validation procedure. HSMMs show the highest accuracy (80%), significantly outperforming HMMs and discriminative models. Simulations show that data with higher temporal resolution, HSMMs reach nearly 100% of accuracy. Our results demonstrate to what extent the sequential nature of movement is critical for accurately inferring behavioural modes from a trajectory and we strongly recommend the use of HSMMs for such purpose. In addition, this work opens perspectives on the use of hybrid HSMM-discriminative models, where a discriminative setting for the observation process of HSMMs could greatly improve inference performance.
- Published
- 2013
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42. Sequencing and analysis of the Mediterranean amphioxus (Branchiostoma lanceolatum) transcriptome.
- Author
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Oulion S, Bertrand S, Belgacem MR, Le Petillon Y, and Escriva H
- Subjects
- Animals, Base Sequence, Molecular Sequence Data, RNA biosynthesis, Sequence Analysis, RNA, Species Specificity, Chordata genetics, Phylogeny, RNA genetics, Transcriptome
- Abstract
Background: The basally divergent phylogenetic position of amphioxus (Cephalochordata), as well as its conserved morphology, development and genetics, make it the best proxy for the chordate ancestor. Particularly, studies using the amphioxus model help our understanding of vertebrate evolution and development. Thus, interest for the amphioxus model led to the characterization of both the transcriptome and complete genome sequence of the American species, Branchiostoma floridae. However, recent technical improvements allowing induction of spawning in the laboratory during the breeding season on a daily basis with the Mediterranean species Branchiostoma lanceolatum have encouraged European Evo-Devo researchers to adopt this species as a model even though no genomic or transcriptomic data have been available. To fill this need we used the pyrosequencing method to characterize the B. lanceolatum transcriptome and then compared our results with the published transcriptome of B. floridae., Results: Starting with total RNA from nine different developmental stages of B. lanceolatum, a normalized cDNA library was constructed and sequenced on Roche GS FLX (Titanium mode). Around 1.4 million of reads were produced and assembled into 70,530 contigs (average length of 490 bp). Overall 37% of the assembled sequences were annotated by BlastX and their Gene Ontology terms were determined. These results were then compared to genomic and transcriptomic data of B. floridae to assess similarities and specificities of each species., Conclusion: We obtained a high-quality amphioxus (B. lanceolatum) reference transcriptome using a high throughput sequencing approach. We found that 83% of the predicted genes in the B. floridae complete genome sequence are also found in the B. lanceolatum transcriptome, while only 41% were found in the B. floridae transcriptome obtained with traditional Sanger based sequencing. Therefore, given the high degree of sequence conservation between different amphioxus species, this set of ESTs may now be used as the reference transcriptome for the Branchiostoma genus.
- Published
- 2012
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43. Use of social information in seabirds: compass rafts indicate the heading of food patches.
- Author
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Weimerskirch H, Bertrand S, Silva J, Marques JC, and Goya E
- Subjects
- Animal Communication, Animals, Behavior, Animal, Cluster Analysis, Geographic Information Systems, Geography, Population Dynamics, Spatial Behavior, Birds physiology, Feeding Behavior, Nesting Behavior physiology
- Abstract
Ward and Zahavi suggested in 1973 that colonies could serve as information centres, through a transfer of information on the location of food resources between unrelated individuals (Information Centre Hypothesis). Using GPS tracking and observations on group movements, we studied the search strategy and information transfer in two of the most colonial seabirds, Guanay cormorants (Phalacrocorax bougainvillii) and Peruvian boobies (Sula variegata). Both species breed together and feed on the same prey. They do return to the same feeding zone from one trip to the next indicating high unpredictability in the location of food resources. We found that the Guanay cormorants use social information to select their bearing when departing the colony. They form a raft at the sea surface whose position is continuously adjusted to the bearing of the largest returning columns of cormorants. As such, the raft serves as a compass signal that gives an indication on the location of the food patches. Conversely, Peruvian boobies rely mainly on personal information based on memory to take heading at departure. They search for food patches solitarily or in small groups through network foraging by detecting the white plumage of congeners visible at long distance. Our results show that information transfer does occur and we propose a new mechanism of information transfer based on the use of rafts off colonies. The use of rafts for information transfer may be common in central place foraging colonial seabirds that exploit short lasting and/or unpredictably distributed food patches. Over the past decades Guanay cormorants have declined ten times whereas Peruvian boobies have remained relatively stable. We suggest that the decline of the cormorants could be related to reduced social information opportunities and that social behaviour and search strategies have the potential to play an important role in the population dynamics of colonial animals.
- Published
- 2010
- Full Text
- View/download PDF
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