In the context of structural condition assessment, transfer learning methods overcome some of the difficulties associated with the paucity of information on the actual structural condition of a ...target structure. This study aims to associate the building’s response with a population of nominally identical buildings for which a form is derived from existing empirical models relating certain basic characteristics (e.g., structure height) with the fundamental resonance period. This paper presents a structural condition classification based on the measured resonance period of the target structure, presented as the Build’Health™ solution. First, damage thresholds are defined by the shift of the fundamental period, which is considered to be a damage-sensitive characteristic for a given building population form, derived from almost thirty published references. The implicit period variation due to certain weather conditions is also included. Multinomial logistic regression and Gaussian mixture models are then used to classify damage according to the performance levels used in earthquake engineering (i.e., Operational Condition, Immediate Occupancy, Life Safety and Collapse Prevention). A performance-based probabilistic framework using a traffic-light system (green-orange-red classification) is finally used to classify structural condition. The method is tested and validated on several buildings surveyed after weak to strong earthquakes with different structural conditions. We show the complementarity of combining transfer learning, which gives the actual state of the target specimen with respect to a nominally identical population form of buildings, with multinomial logistic regressions and Gaussian mixture models for operational condition-based decision-making defined by the measured resonance period. This manuscript is the second in a series aimed at developing the Build’Health™ operational method for assessing the condition of real buildings (Part I on damage detection using transfer learning and Part II on classification using Gaussian mixture models and multinomial logistic regressions) based on basic building information.
•Structural condition classification based on the measured resonance period of the target structure.•Damage thresholds defined by the shift of the fundamental period found in references, for a given building population form.•Multinomial logistic regression and Gaussian mixture models used to classify damage according to the performance levels.•Performance-based probabilistic framework using a traffic-light system used to classify structural condition.•Test and validation on several buildings with different structural conditions.
When the yeast protein Ypr140w was expressed in Escherichia coli, a lyso-PC lysophosphatidylcholine (1-acylglycerophosphorylcholine) acyltransferase activity was found associated with the membranes ...of the bacteria. To our knowledge, this is the first identification of a protein capable of catalysing the acylation of lyso-PC molecules to form PC. Fluorescence microscopy analysis of living yeasts revealed that the fusion protein Ypr140w-green fluorescent protein is targeted to the mitochondria. Moreover, in contrast with wild-type cells, in the absence of acyl-CoA, the yeast mutant deleted for the YPR140w gene has no lyso-PC acyltransferase activity associated with the mitochondrial fraction. When yeast cells were grown in the presence of lactate, the mutant synthesized 2-fold more triacylglycerols when compared with the wild-type. Moreover, its mitochondrial membranes contained a lesser amount of PC and cardiolipin, and the fatty acid composition of these latter was greatly changed. These modifications were accompanied by a 2-fold increase in the respiration rates (states 3 and 4) of the mitochondria. The relationship between the deletion of the YPR140w gene and the lipid composition of the ypr140wDelta cells is discussed.
Summary
A yeast mutant was isolated that was resistant to Bax‐induced cell death. It supports a mutation leading to decreased amounts of the protein Uth1p. A strain in which the UTH1 gene is ...disrupted also exhibits resistance to Bax expression. The absence of Uth1p does not change the mitochondrial localization of Bax, its insertion in the mitochondrial outer membrane or its cytochrome c‐releasing activity. On the other hand, the absence of Uth1p does prevent the appearance of other hallmarks related to Bax expression in yeast, such as oxidation of mitochondrial lipid, production of reactive oxygen species and maintenance of plasma membrane properties after ethanol stress. The absence of Uth1p was also found to induce resistance to rapamycin, a specific inducer of autophagy. This resistance only appears when cells are grown under respiratory conditions, but not under fermentative conditions, suggesting that Uth1p acts in an autophagic pathway involving mitochondria, in accordance with its main localization in the outer mitochondrial membrane. Taken together, these data show that Bax is able to activate a death pathway related to autophagy in yeast, which also exhibits typical hallmarks of apoptosis, revealing a possible dual function of Bax in both types of death. This hypothesis is discussed in the light of observations suggesting a co‐regulation of apoptosis and autophagy in mammalian cells.
The aim of this study was to determine whether fatty acid composition of leaves, cotyledons or roots could be used as an indicator of the bioavailability and of the adverse effects of heavy metals on ...plants. Tomato seedlings were grown on soils obtained by mixing increasing amounts of a highly metal‐contaminated soil with an uncontaminated sandy soil, and the fatty acid composition of plant tissues was analyzed. The fatty acid composition of roots and cotyledons of plants grown on contaminated soils was mostly the same as in the control plants. In contrast, significant changes in the fatty acid composition of primary leaves occurred. Our results clearly indicate a relationship between metal accumulation (Cd, Pb, Zn, and Cu) and the fatty acid composition of primary leaves, with the contribution of 18 C atom fatty acids (as 18:3 fatty acid and precursors) being more closely correlated with the availability of heavy metals in soils.
Lipid oxidation and autophagy in yeast Kiššová, Ingrid; Deffieu, Maïka; Samokhvalov, Victor ...
Free radical biology & medicine,
12/2006, Letnik:
41, Številka:
11
Journal Article
Recenzirano
Autophagy, a process involved in the degradation and the recycling of long-lived proteins and organelles to survive nitrogen starvation, is generally non-selective. However, recent data suggest that ...selective forms of autophagy exist, that are able to specifically target several organelles, including mitochondria. Conversely, mitochondrial alterations could trigger autophagy. Such a selective form of autophagy might be involved in the elimination of damaged mitochondria. We reported previously that, mitochondria were early targets of rapamycin-induced autophagy. Here we report that rapamycin-induced autophagy is accompanied by the early production of reactive oxygen species and by the early oxidation of mitochondrial lipid. Inhibition of these oxidative effects by resveratrol largely impaired autophagy of both cytosolic proteins and mitochondria, and delayed subsequent cell death. These results support a role of mitochondrial oxidation events in the activation of autophagy.
The oxidant function of pro‐apoptotic protein Bax was investigated through heterologous expression in yeast. Direct measurements of fatty acid content show that Bax‐expression induces oxidation of ...mitochondrial lipids. This effect is prevented by the coexpression of Bcl‐xL. The oxidation actually could be followed on isolated mitochondria as respiration‐induced peroxidation of polyunsaturated cis‐parinaric acid and on whole cells as the increase in the amount of thiobarbituric acid‐reactive products. Treatments that increase the unsaturation ratio of lipids, making them more sensitive to oxidation, increase kinetics of Bax‐induced death. Conversely, inhibitors of lipid oxidation and treatments that decrease the unsaturation ratio of fatty acids decrease kinetics of Bax‐induced death. Taken together, these results show that Bax‐induced mitochondrial lipid oxidation is relevant to Bax‐induced cell death. Conversely, lipid oxidation is poorly related to the massive Bax‐induced superoxide and hydrogen peroxide accumulation, which occurs at the same time, as chemical or enzymatic scavenging of ROS does not prevent lipid oxidation nor has any effects on kinetics of Bax‐induced cell death. Whatever the origin of mitochondrial lipid oxidation, these data show that it represents a major step in the cascade of events leading to Bax‐induced cell death. These results are discussed in the light of the role of lipid oxidation both in mammalian apoptosis and in other forms of cell death in other organisms.
The transfer and subsequent metabolism of lysophosphatidylcholine between subcellular compartments were studied in vitro by embedding membranes in alginate beads. After several experiments to ...validate the process, it was demonstrated that lysophosphatidylcholine was transferred from microsomes embedded in alginate beads to immobilized chloroplasts, that this transfer involved the partition of this molecule, and that the imported lysophosphatidylcholine was further used as substrate for phosphatidylcholine biosynthesis. More generally, the technique used makes it possible to avoid any cross-contamination between compartments, to evidence a transfer of molecules, and to study the metabolism of the imported molecules in the acceptor compartment.
Non-English title Gabriel, Frederic; Accoceberry, Isabelle; Bessoule, Jean-Jacques ...
Journal de mycologie médicale,
09/2015, Letnik:
25, Številka:
3
Journal Article
Recenzirano
Original Abstract: Introduction: Les cellules phagocytaires des lignees monocytaire et neutrophile sont essentielles a la defense de l'organisme au cours d'une infection a Candida spp. Cependant in ...vitro, C. albicans, C. glabrata et C. lusitaniae sont capables de resister a la phagocytose. Notre hypothese est que les lipides, et en particulier les acides gras, pourraient constituer une ressource energetique privilegiee pour la levure afin de resister a la phagocytose. Chez les levures Ascomycetes, le catabolisme des acides gras est presume etre exclusivement localise dans les peroxysomes et repose principalement sur la beta -oxydation. Methodes Nous avons construit par recombinaison homologue chez C. lusitaniae 11 mutants nuls (simples, doubles ou triples) afin de bloquer la beta -oxydation peroxysomale (genes FOX1, FOX2, FOX3), mais aussi en amont l'import peroxysomal des acides gras a longue chaine carbonee (gene PXA1) et en aval le cycle du glyoxylate (gene ICL1). La caracterisation du phenotype des mutants obtenus a compris l'etude : - de l'assimilation des sources de carbone ; - de la consommation d'un substrat radioactif de la beta -oxydation par des extraits bruts et fractions cellulaires ; - de l'immunolocalisation de la proteine Fox2 (western blot sur fractions cellulaires, microscopie electronique) ; - de la resistance in vitro a la phagocytose macrophagique (modele developpe au laboratoire) ; - de leur virulence dans un modele murin de candidemie. Resultats Contrairement a ce qui est rapporte pour C. albicans, l'inactivation du gene FOX2 (ou des genes FOX1 ou FOX3) ne se traduit pas par un blocage du catabolisme des acides gras chez C. lusitaniae. Nos travaux ont permis d'expliquer ce phenotype original par l'existence de 3 voies pour le catabolisme des acides gras chez C. lusitaniae et de demontrer la colocalisation inedite chez les Eucaryotes de la proteine Fox2 au peroxysome et a la mitochondrie. A 6 h d'infection, la survie des macrophages infectes par le mutant fox2 Delta etait comprise entre celle des macrophages infectes par la souche sauvage (la plus faible) et celle des macrophages infectes par le mutant icl1 Delta (la plus forte). Les mutants icl1 Delta et fox2 Delta se multipliaient moins que la souche sauvage. La virulence in vivo du mutant icl1 Delta etait attenuee, alors que celle du mutant fox2 Delta n'etait pas differente de la souche sauvage. Conclusion: Le cycle peroxysomal de l'acide glyoxylique est indispensable pour la virulence de C. lusitaniae, et l'acetyl-CoA qui l'alimente ne provient pas seulement de la s-oxydation des acides gras.
Les cellules phagocytaires des lignées monocytaire et neutrophile sont essentielles à la défense de l’organisme au cours d’une infection à Candida spp. Cependant in vitro, C. albicans, C. glabrata et ...C. lusitaniae sont capables de résister à la phagocytose. Notre hypothèse est que les lipides, et en particulier les acides gras, pourraient constituer une ressource énergétique privilégiée pour la levure afin de résister à la phagocytose. Chez les levures Ascomycètes, le catabolisme des acides gras est présumé être exclusivement localisé dans les peroxysomes et repose principalement sur la β-oxydation.
Nous avons construit par recombinaison homologue chez C. lusitaniae 11 mutants nuls (simples, doubles ou triples) afin de bloquer la β-oxydation peroxysomale (gènes FOX1, FOX2, FOX3), mais aussi en amont l’import peroxysomal des acides gras à longue chaîne carbonée (gène PXA1) et en aval le cycle du glyoxylate (gène ICL1). La caractérisation du phénotype des mutants obtenus a compris l’étude :
– de l’assimilation des sources de carbone ;
– de la consommation d’un substrat radioactif de la β-oxydation par des extraits bruts et fractions cellulaires ;
– de l’immunolocalisation de la protéine Fox2 (western blot sur fractions cellulaires, microscopie électronique) ;
– de la résistance in vitro à la phagocytose macrophagique (modèle développé au laboratoire) ;
– de leur virulence dans un modèle murin de candidémie.
Contrairement à ce qui est rapporté pour C. albicans, l’inactivation du gène FOX2 (ou des gènes FOX1 ou FOX3) ne se traduit pas par un blocage du catabolisme des acides gras chez C. lusitaniae. Nos travaux ont permis d’expliquer ce phénotype original par l’existence de 3 voies pour le catabolisme des acides gras chez C. lusitaniae et de démontrer la colocalisation inédite chez les Eucaryotes de la protéine Fox2 au peroxysome et à la mitochondrie. À 6h d’infection, la survie des macrophages infectés par le mutant fox2Δ était comprise entre celle des macrophages infectés par la souche sauvage (la plus faible) et celle des macrophages infectés par le mutant icl1Δ (la plus forte). Les mutants icl1Δ et fox2Δ se multipliaient moins que la souche sauvage. La virulence in vivo du mutant icl1Δ était atténuée, alors que celle du mutant fox2Δ n’était pas différente de la souche sauvage.
Le cycle peroxysomal de l’acide glyoxylique est indispensable pour la virulence de C. lusitaniae, et l’acétyl-CoA qui l’alimente ne provient pas seulement de la ß-oxydation des acides gras.
The volume of data, and the large number of biological variables to be tested (one hundred), require analytical techniques, such as Random Forests, which can overcome the problem of multi-colinearity ...for the selection of indicators, sensitive to various factors. Random Forests methodology is appropriate for the selection of the most discriminant variables. So, we searched for the best way to select them, by bringing together all biological variables, representing the Microflora and Fauna. This approach focuses on impact indicators from the Bio2 program, indicators of flora and indicators of accumulation (snails) were not included. This work has been implemented on the three factors of discrimination : land use, metallic contamination levels and organic contamination levels. We grouped the most discriminating variables from each RF analysis. Linear discriminant analysis was then implemented for each factor, in order to develop a predictive model.
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