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Mineral Balance Plasticity of Cloudberry (<i>Rubus chamaemorus</i>) in Quebec-Labrador Bogs

American Journal of Plant Sciences 2013年第7期4卷 1508-1520页

作者： Léon Etienne Parent Serge-étienne Parent Valérie Hébert-Gentile Kristine Naess line lapointe Centre d’études de la Forêt Department of Biology Université Laval Québec Canada Centre d’études de la Forêt Department of Biology Université Laval Québec Canada Centre de Recherches Les Buissons Pointe-aux-Outardes Canada. Department of Soils and Agrifood Engineering Université Laval Québec Canada

The “ionome”, or plant elemental signature, is the elemental composition of an organisms, that may vary with genotypic traits and phenotypic plasticity. Cloudberry (Rubus chamaemorus L.) is a circumboreal wild berry naturally growing in oligotrophic oceanic bogs ofQuebecandLabrador. Our objective was to relate cloudberry stand productivity to the ionomes of female ramets and explore the cause of nutrient imbalance in low-performing stands. We analyzed 13 elements in female ramets collected in 86 natural sites where crop productivity varied widely. We computed orthogonally arranged balances reflecting plant stoichiometric rules and soil biogeochemistry. Balances were expressed as isometric log ratios (ilr) between ad hoc sub-compositions. Balances were synthesized into a Mahalanobis distance optimized based on receiving operating characteristics (ROC). The critical Mahalanobis distance was found to be 5.29 for cutoff berry yield of3.8 g.m-2 with test performance of 0.88, as measured by the area under the ROC curve. Although past research on cloudberry focused mainly on the N/P ratio, this exploratory mineral balance analysis indicated that imbalance in the [P,N | S,C] and [Al | Nutrients] partitions appeared to be the factors limiting the most cloudberry productivity in the bogs. Some highly productive stands showed relatively high C fixation and K use efficiency. Due to the complexity of interactions, diagnosis should be conducted computing first a global imbalance index (Mahalanobis distance), then examining in the balance domain binary partitions departing most from reference, and finally appreciating relative shortage, sufficiency or excess of elements in the concentration domain.

关键词： Al Toxicity Cloudberry Compositional Data Analysis Isometric Log Ratio Nutrient Balance Ionome

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A statistical procedure to assess the significance level of barriers to gene flow

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Journal of Genetics and Genomics 2009年第11期36卷 685-693页

作者： Sébastien Rioux Paquette Franois-Joseph lapointe Allan Wilson Centre for Molecular Ecology & School of Biological Sciences Victoria University of Wellington Département de Sciences Biologiques Université de Montréal

Although several methods are available to study the extent of isolation by distance （IBD） among natural populations, comparatively few exist to detect the presence of sharp genetic breaks in genetic distance datasets. In recent years, Monmonier＇s maximum-difference algorithm has been increasingly used by population geneticists. However, this method does not provide means to measure the statistical significance of such barriers, nor to determine their relative contribution to population differentiation with respect to IBD. Here, we propose an approach to assess the significance of genetic boundaries. The method is based on the calculation of a multiple regression from distance matrices, where binary matrices represent putative genetic barriers to test, in addition to geographic and genetic distances. Simulation results suggest that this method reliably detects the presence of genetic barriers, even in situations where IBD is also significant. We also illustrate the methodology by analyzing previously published datasets. Conclusions about the importance of genetic barriers can be misleading if one does not take into consideration their relative contribution to the overall genetic structure of species.

关键词： genetic barriers genetic distances isolation by distance multiple regression on distance matrices partial regression coefficients

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A multilevel process view of organizational knowledge transfer: enablers versus barriers

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Journal of Management Analytics 2018年第1期5卷 1-17页

作者： Isaac Vaghefi Liette lapointe Hamidreza Shahbaznezhad School of Management The State University of New York at BinghamtonBinghamtonNYUSA Desautels Faculty of Management McGill UniversityMontrealCanada Information Systems and Operations Management University of Auckland Business SchoolAucklandNew Zealand

The importance of knowledge as a strategic asset for organizations has been recognized by both researchers and *** gain a competitive advantage,firms are required to effectively manage their knowledge *** most central activity in managing knowledge is to ensure its transfer within and between *** transfer(KT)has thus been recognized as a key component of the knowledge management *** purpose of this research is to provide a holistic view of the KT barriers and enablers within an organization,from a multilevel and process-based *** first review the extant literature to identify the key enablers and barriers to ***,we develop a multilevel conceptualization of enablers and barriers that can influence KT at different levels–individual,team/exchange and *** proposed model improves current understanding of KT by offering a holistic and integrated view of enablers and barriers.

关键词： knowledge transfer enablers barriers process model

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Nonlinear increase,invisibility,and sign inversion of a localized fs-laser-induced refractive index change in crystals and glasses

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Light(Science & Applications) 2020年第1期9卷 1398-1409页

作者： Jerome lapointe Jean-Philippe Berube Yannick Ledemi Albert Dupont Vincent Fortin Younes Messaddeq Real Vallee Centre d’Optique Photonique et Laser2375 Rue de la TerrasseUniversite LavalG1V 0A6 QuebecQCCanada

Multiphoton absorption via ultrafast laser focusing is the only technology that allows a three-dimensional structural modification of transparent ***,the magnitude of the refractive index change is rather limited,preventing the technology from being a tool of choice for the manufacture of compact photonic integrated *** propose to address this issue by employing a femtosecond-laser-induced electronic band-gap shift(FLIBGS),which has an exponential impact on the refractive index change for propagating wavelengths approaching the material electronic resonance,as predicted by the Kramers–Kronig *** by theoretical calculations,based on a modified Sellmeier equation,the Tauc law,and waveguide bend loss calculations,we experimentally show that several applications could take advantage of this ***,we demonstrate waveguide bends down to a submillimeter radius,which is of great interest for higher-density integration of fs-laser-written quantum and photonic *** also demonstrate that the refractive index contrast can be switched from negative to positive,allowing direct waveguide inscription in ***,the effect of the FLIBGS can compensate for the fs-laser-induced negative refractive index change,resulting in a zero refractive index change at specific wavelengths,paving the way for new invisibility applications.

关键词： waveguide millimeter refractive

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Sewage pollution in Negril, Jamaica: effects on nutrition and ecology of coral reef macroalgae

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Chinese Journal of Oceanology and Limnology 2011年第4期29卷 775-789页

作者： B. E. lapointe K. THACKER C. HANSON L. GETTEN Harbor Branch Oceanographic Institute at Florida Atlantic University 5600 US 1 North Ft. Pierce FL 34946 USA Negril Coral Reef Preservation Society P. O. Box 2563 Negril Jamaica West Indies

Coral reefs in the Negril Marine Park （NMP）, Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C：N：P and stable nitrogen isotope ratios （δ^15N） of abundant reef macroalgae on shallow and deep reefs of the NMP in 1998 showed strong P-limitation and evidence of increasing sewage pollution. In 1999, a sewage collection and treatment project began diverting wastewater from the resort and urban areas to a pond system that discharged partially-treated effluent into the South Negril River （SNR）. These sewage discharges significantly increased concentrations of NH2 and SRP （N：P -13） in the SNR, which flows into Long Bay and around Negril＇s ＂West End＂. Concentrations of SRP, the primary limiting nutrient, were higher on shallow reefs of the West End in 2001 compared to 1998. Stable nitrogen isotope ratios （δ^15N） of abundant reef macroalgae on both shallow and deep reefs of the West End in 2002 were significantly higher than baseline values in 1998, indicating an escalating impact of sewage nitrogen pollution over this timeframe. The increased nutrient concentrations and δ^15N enrichment of reef macroalgae correlated with blooms of the chlorophyte Chaetornorpha linum in shallow waters of Long Bay and Codium isthrnocladum and Caulerpa cupressoides on deep reefs of the West End. Sewage treatment systems adjacent to coral reefs must include nutrient removal to ensure that DIN and SRP concentrations, after dilution, are below the low thresholds noted for these oligotrophic ecosystems.

关键词： macroalgae sewage carbon nitrogen phosphorus stable nitrogen isotopes eutrophication

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Physiological evidence of integrin-antibody reactive proteins influencing the innate cellular immune responses of larval Galleria mellonella hemocytes

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Insect Science 2020年第2期27卷 239-255页

作者： Jason F.lapointe Connor D.McCarthy Gary B.Dunphy Craig A.Mandato Department of Anatomy and Cell Biology McGill UniversityMontrealCanada Department of Natural Resource Sciences Macdonald CampusSte.Anne De BellevueCanada

Larval Galleria melonella(L.)hemocytes form microaggregates in response to stimulation by Gram-positive bacteria Hemocyte adhesion to foreign materials is mediated by the CAMP/protein kinase A pathway and the B-subunit of cholera toxin using a cAMP-independent *** toxin-induced microaggregation was inhibited by the integrin inhibitory RGDS peptide,implying integrins may be part of the *** on the types of mammalian integrin-antibody reactive proteins affecting hemocyte adhesion and bacterial-induced responses ars,ory,Ai,and B3 subunits occred on both granular cell and plasmatocyte hemocyte subtypes.A fluorescent band representing the binding of rabbit as-integrin subunit antibodies occurred between adhering heterotypic *** frequency of the bands was increased by cholera *** as andβrabbit integrin subunit antibodies inhibited removal of Bacillus subtilis(Cohn)from the hemolymph in vivo,A as ir-specific synthetic peptide blocker similarly diminished hemocyte function whereas the 0v Bs-specific inhibitory peptide and the corresponding integrin subunit antibodies did not influence nonself hemocyte *** blots revealed several proteins reacting with a given integrin-antibody *** integrin-antibody reactive proteins(which may include integrins)with possible as and B epitopes modulate immediate hemocyte *** microscopy established plasmatocyte adhesion to and rosetting over substrata followved by granular cell microaggregate adhesion to plasmatocytes during early stage nodulation.

关键词： hemocyte response integrin-antibody reactive protein

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Mechanism and evolution of multidomain aminoacyl-tRNA synthetases revealed by their inhibition by analogues of a reaction intermediate, and by properties of truncated forms

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Journal of Biomedical Science and Engineering 2013年第10期6卷 943-946页

作者： Jacques lapointe Département de Biochimie de Microbiologie et de Bioinformatique Regroupement Québécois de Recherche sur la Fonction la Structure et L’ingénierie des Protéines (PROTEO) & Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec Canada

Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tRNA synthetases (aaRS), is an L-shaped molecule whose size in one dimension is similar to that of its cognate aaRS. Crystallographic structures of aaRS/tRNA complexes show that these enzymes use several of their structural domains to interact with their cognate tRNA. This mini review discusses first some aspects of the evolution and of the flexibility of the pentadomain bacterial glutamyl-tRNA synthetase (GluRS) revealed by kinetic and interaction studies of complementary truncated forms, and then illustrates how stable analogues of aminoacyl-AMP intermediates have been used to probe conformational changes in the active sites of Escherichia coli GluRS and of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) of Pseudomonas aeruginosa.

关键词： Multidomain Enzymes tRNA Aminoacyl-tRNA Synthetases Truncated Enzymes Steady-State Kinetics Inhibitors Mechanism Evolution

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Nonalcoholic steatohepatitis severity is defined by a failure in compensatory antioxidant capacity in the setting of mitochondrial dysfunction

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World Journal of Gastroenterology 2018年第16期24卷 1748-1765页

作者： Michelle L Boland Stephanie Oldham Brandon B Boland Sarah Will Jean-Martin lapointe Silvia Guionaud Christopher J Rhodes James L Trevaskis Cardiovascular and Metabolic Diseases MedImmune LLC Pathology MedImmune Ltd. Pathology Drug Safety and MetabolismIMED Biotech UnitAstraZeneca

AIM To comprehensively evaluate mitochondrial(dys) function in preclinical models of nonalcoholic steatohepatitis(NASH).METHODS We utilized two readily available mouse models of nonalcoholic fatty liver disease(NAFLD) with or without progressive fibrosis: Lep^(ob)/Lep^(ob)(ob/ob) and FATZO mice on high trans-fat, high fructose and high cholesterol(AMLN) diet. Presence of NASH was assessed using immunohistochemical and pathological techniques, and gene expression profiling. Morphological features of mitochondria were assessed via transmission electron microscopy and immunofluorescence, and function was assessed by measuring oxidative capacity in primary hepatocytes, and respiratory control and proton leak in isolated mitochondria. Oxidative stress was measured by assessing activity and/or expression levels of Nrf1, Sod1, Sod2, catalase and 8-OHdG. RESULTS When challenged with AMLN diet for 12 wk, ob/ob and FATZO mice developed steatohepatitis in the presence of obesity and hyperinsulinemia. NASH development was associated with hepatic mitochondrial abnormalities, similar to those previously observed in humans, including mitochondrial accumulation and increased proton leak. AMLN diet also resulted in increased numbers of fragmented mitochondria in both strains of mice. Despite similar mitochondrial phenotypes, we found that ob/ob mice developed more advanced hepatic fibrosis. Activity of superoxide dismutase(SOD) was increased in ob/ob AMLN mice, whereas FATZO mice displayed increased catalase activity, irrespective of diet. Furthermore, 8-OHd G, a marker of oxidative DNA damage, was significantly increased in ob/ob AMLN mice compared to FATZO AMLN mice. Therefore, antioxidant capacity reflected as the ratio of catalase:SOD activity was similar between FATZO and C57 BL6 J control mice, but significantly perturbed in ob/ob mice. CONCLUSION Oxidative stress, and/or the capacity to compensate for increased oxidative stress, in the setting of mitochondrial dysfunction, is

关键词： Nonalcoholic steatohepatitis Steatosis Fibrosis Mitochondrial function Oxidative stress

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Theoretical and experimental biology in one<br>—A symposium in honour of Professor Kuo-Chen Chou’s 50th anniversary and Professor Richard Giegé’s 40th anniversary of their scientific careers

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Journal of Biomedical Science and Engineering 2013年第4期6卷 435-442页

作者： Sheng-Xiang Lin Jacques lapointe Department of Biochemistry Microbiology and Bioinformatics and PROTEO Laval University Quebec Canada Laboratory of Molecular Endocrinology and Oncology Research Center of Laval University Hospital Center (CHUQ-CHUL) and PROTEO Laval University Quebec Canada

It has been a dream that theoretical biology can be extensively applied in experimental biology to accelerate the understanding of the sophiscated movements in living organisms. A brave assay and an excellent example were represented by enzymology, in which the well-established physico-chemistry is used to describe, to fit, to predict and to improve enzyme reactions. Before the modern bioinformatics, the developments of the combination of theoretical biology and experimental biology have been mainly limited to various classic formulations. The systematic use of graphic rules by Prof. Kuo-Chen Chou and his co-workers has significantly facilitated to deal with complicated enzyme systems. With the recent fast progress of bioinformatics, prediction of protein structures and various protein attributes have been well established by Chou and co-workers, stimulating the experimental biology. For example, their recent method for predicting protein subcellular localization (one of the important attributes of proteins) has been extensively applied by scientific colleagues, yielding many new results with thousands of citations. The research by Prof. Chou is characterized by introducing novel physical concepts as well as powerful and elegant mathematical methods into important biomedical problems, a focus throughout his career, even when facing enormous difficulties. His efforts in 50 years have greatly helped us to realize the dream to make “theoretical and experimental biology in one”. Prof. Richard Giege is well known for his multi-disciplinary research combining physics, chemistry, enzymology and molecular biology. His major focus of study is on the identity of tRNAs and their interactions with aminoacyl-tRNA synthetases (aaRS), which are of critical importance to the fidelity of protein biosynthesis. He and his colleagues have carried out the first crystallization of a tRNA/aaRS complex, that between tRNAAsp and AspRS from yeast. The determination of the complex structure c

关键词： Theoretical Biology Experimental Biology Chou’s Graphic Rules in Enzymology Prediction of Protein Attributes Chou’s Invariance Theorem Macromolecular Crystallogenesis tRNA Identity on Aminoacylation Specificity Physico-Biochemistry

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C5L2 Deficiency Enhances Development of Atherosclerosis in ApoE Knockout Mice

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Chinese Medicine 2015年第1期6卷 61-74页

作者： Yan Liu Alexandre Fisette Marc lapointe Katherine Cianflone Centre de Recherche de l’Institut Universitaire de Cardiologie & Pneumologie de Québec Université Laval Québec Canada Department of Pediatrics Tongji Hospital Huazhong University of Science and Technology Wuhan China

Background: The complement system is important in development of atherosclerosis via regulation of lipid and glucose metabolism as well as inflammation. Aim: The aim of the present study was to further analyze the contribution of C5L2 to the development of atherosclerosis. We proposed that, with DIO feeding, C5L2 deficiency would promote a phenotype that encourages atherosclerosis development. Coupled to ApoE deficiency, double knockout (2KO) mice would show exacerbated atherosclerotic plaque formation. Methods: First, Wildtype (WT) and C5L2-/-(C5L2KO) and subsequently, ApoE-/-(ApoEKO) and C5L2/ApoE double knockout mice were placed on diets inducing obesity (DIO) or standard chow diet for 12 - 15 weeks. Plasma lipids, glucose, cytokines and hepatic glycogen and lipid contents, mRNA levels and enzyme activities and atherosclerotic plaque size were measured. Results: C5L2KO had increased hepatic glucose oxidation (+90%, p < 0.001), reduced liver glycogen content on chow diet (-34%, p < 0.05) but increased with DIO (+51%, p < 0.05) vs WT. Glucose clearance was delayed in C5L2/ApoE-2KO vs ApoEKO mice with chow (p < 0.0001) and DIO diet (p = 0.0026). C5L2KO mice had increased hepatic lipid content and fatty acid synthesis but decreased lipid oxidation vs WT. Plasma cholesterol was further elevated in C5L2/ApoE-2KO vs ApoEKO with DIO feeding (p < 0.05). Hepatic cytokine expression was increased in C5L2KO mice compared to WT mice. Atherosclerotic plaque size was increased in C5L2/ ApoE-2KO mice compared with apoEKO on chow (p < 0.05) and DIO regimen (p < 0.001). Conclusions: C5L2 disruption worsens glucose and lipid metabolism, increases hepatic and circulating inflammation, and aggravates atherosclerosis.

关键词： Atherosclerosis C5L2 Inflammation Metabolism Lipid Glucose

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