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Lytic polysaccharide monooxygenases (LPMOs) facilitate cellulose nanofibrils production
No full textBackgroundLytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that cleave polysaccharides through an oxidative mechanism. These enzymes are major contributors to the recycling of carbon in nature and are currently used in the biorefinery industry. LPMOs are commonly used in synergy with cellulases to enhance biomass deconstruction. However, there are few examples of the use of monocomponent LPMOs as a tool for cellulose fibrillation. In this work, we took advantage of the LPMO action to facilitate disruption of wood cellulose fibers as a strategy to produce nanofibrillated cellulose (NFC).ResultsThe fungal LPMO from AA9 family (PaLPMO9E) was used in this study as it displays high specificity toward cellulose and its recombinant production in bioreactor is easily upscalable. The treatment of birchwood fibers with PaLPMO9E resulted in the release of a mixture of C1-oxidized oligosaccharides without any apparent modification in fiber morphology and dimensions. The subsequent mechanical shearing disintegrated the LPMO-pretreated samples yielding nanoscale cellulose elements. Their gel-like aspect and nanometric dimensions demonstrated that LPMOs disrupt the cellulose structure and facilitate the production of NFC.ConclusionsThis study demonstrates the potential use of LPMOs as a pretreatment in the NFC production process. LPMOs weaken fiber cohesion and facilitate fiber disruption while maintaining the crystallinity of cellulose
A multiplatform metabolomic approach to characterize fecal signatures of negative postnatal events in chicks: a pilot study
No full textDispersal heterogeneity in the spatial Lambda-Fleming-Viot process
No full textWe study the evolution of gene frequencies in a spatially distributed population when the dispersal of individuals is not uniform in space. We adapt the \slfv to this setting and consider that individuals spread their offspring farther from themselves at each generation in one halfspace than in the other. We study the large scale behaviour of this process and show that the motion of ancestral lineages is asymptotically close to a family of skew Brownian motions which coalesce upon meeting in one dimension, but never meet in higher dimension. This leads to a generalization of a result due to Nagylaki on the scaling limits of the gene frequencies: the non-uniform dispersal causes a discontinuity in the slope of the gene frequencies but the gene frequencies themselves are continuous across the interface
Two FtsH proteases contribute to fitness and adaptation of Pseudomonas aeruginosa Clone C Strains
No full textPseudomonas aeruginosais an environmental bacterium and a nosocomial pathogenwith clone C one of the most prevalent clonal groups. TheP. aeruginosaclone Cspecific genomic island PACGI-1 harbors a xenolog offtsHencoding a functionallydiverse membrane-spanning ATP-dependent metalloprotease on the core genome. Inthe aquatic isolateP. aeruginosaSG17M, the core genome copyftsH1significantlyaffects growth and dominantly mediates a broad range of phenotypes, such assecretion of secondary metabolites, swimming and twitching motility and resistance toaminoglycosides, while the PACGI-1 xenologftsH2backs up the phenotypes in theftsH1mutant background. The two proteins, with conserved motifsfor disaggregaseand protease activity present in FtsH1 and FtsH2, have the ability to form homo- andhetero-oligomers withftsH2distinctively expressed in the late stationary phase ofgrowth. However, mainly FtsH1 degrades a major substrate, the heat shock transcriptionfactor RpoH. Pull-down experiments with substrate trap-variants inactive in proteolyticactivity indicate both FtsH1 and FtsH2 to interact with the inhibitory protein HflC,while the phenazine biosynthesis protein PhzC was identified as a substrate of FtsH1.In summary, as an exception inP. aeruginosa, clone C harbors two copies of theftsHmetallo-protease, which cumulatively are required for theexpression of a diversityof phenotypes
Chemical variability of the essential oil of origanum ehrenbergii boiss. from Lebanon, Assessed by independent component analysis (ica) and common component and Specific weight analysis (ccswa)
No full textOriganum ehrenbergii Boiss., an endemic plant to Lebanon, is widely acknowledged in Lebanese traditional medicine. The aim of the present study was to evaluate the influence of the drying method, region, and time of harvest on yield and chemical composition of O. ehrenbergii essential oils (EOs). Plants were harvested monthly throughout 2013 and 2014, from two different regions, Aabadiye and Qartaba, then dried using two drying methods: lyophilization and shade-drying at 4 degrees C. EO was extracted by hydrodistillation and analyzed by GC/MS. GC-MS data, combined with independent component analysis (ICA) and common component and specific weight analysis (CCSWA), showed that drying techniques, region of harvest, and soil composition have no effect on the chemical composition of O. ehrenbergii EOs. Of the factors analyzed, only harvesting time affected the EO composition of this species. High and stable amounts of carvacrol, associated with reliable antimicrobial activities, were detected in material harvested between March and October. EOs obtained from plants harvested in Aabadiye in January and February showed high amounts of thymoquinone, related to anti-inflammatory and cytotoxic effects. The use of ICA and CCSWA was proven to be efficient, and allowed the development of a discriminant model for the classification of O. ehrenbergii chemotype and the determination of the best harvesting time
Aplicación de correlaciones parciales y teoría de la información a redes de estimas de consanguinidad en conejos
No full textThis study aims to implement partial correlations and information theory to
assess the relation between different estimators of inbreeding and phenotypes using a
selected population of rabbits. Pedigree data and genomic information from a 200K chip were
available. After filtering, the data set constituted 490 animals genotyped for 114,604 autosomal
SNPs. The evaluated methodology allows inferring meaningful associations between
estimates of inbreeding appropriately
Reduced phosphorus loads from the loire and vilaine rivers were accompanied by increasing eutrophication in the vilaine Bay (south brittany, france)
No full textThe evolution of eutrophication parameters (i.e., nutrients and phytoplankton biomass) during recent decades was examined in coastal waters of the Vilaine Bay (VB, France) in relation to changes in the Loire and Vilaine rivers. Dynamic linear models were used to study long-term trends and seasonality of dissolved inorganic nutrient and chlorophyll a concentrations (Chl a) in rivers and coastal waters. For the period 1997-2013, the reduction in dissolved riverine inorganic phosphorus (DIP) concentrations led to the decrease in their Chl a levels. However, while dissolved inorganic nitrogen (DIN) concentrations decreased only slightly in the Vilaine, they increased in the Loire, specifically in summer. Simultaneously, phytoplankton in the VB underwent profound changes with increase in biomass and change in the timing of the annual peak from spring to summer. The increase in phytoplankton biomass in the VB, manifested particularly by increased summer diatom abundances, was due to enhanced summer DIN loads from the Loire, sustained by internal regeneration of DIP and dissolved silicate (DSi) from sediments. The long-term trajectories of this case study evidence that significant reduction of P inputs without simultaneous N abatement was not yet sufficient to control eutrophication all along the Loire-Vilaine-VB continuum. Upstream rivers reveal indices of recoveries following the significant diminution of P, while eutrophication continues to increase downstream, especially when N is the limiting factor. More N input reduction, paying particular attention to diffuse N sources, is required to control eutrophication in receiving VB coastal waters. Internal benthic DIP and DSi recycling appears to have contributed to the worsening of summer VB water quality, augmenting the effects of anthropogenic DIN inputs. For this coastal ecosystem, nutrient management strategies should consider the role played by internal nutrient loads to tackle eutrophication processes
Quantifying Uncertainty Due to stochastic Weather Generators in Climate Change Impact studies
No full textClimate change studies involve complex processes translating coarse climate change projections in locally meaningful terms. We analysed the behaviour of weather generators while downscaling precipitation and air temperature data. With multiple climate indices and alternative weather generators, we directly quantified the uncertainty associated with using weather generators when site specific downscaling is performed. We extracted the influence of weather generators on climate variability at local scale and the uncertainty that could affect impact assessment. For that, we first designed the downscaling experiments with three weather generators (CLIMAK, LARs-WG, WeaGets) to interpret future projections. then we assessed the impacts of estimated changes of precipitation and air temperature for a sample of 15 sites worldwide using a rice yield model and an extended set of climate metrics. We demonstrated that the choice of a weather generator in the downscaling process may have a higher impact on crop yield estimates than the climate scenario adopted. should they be confirmed, these results would indicate that widely accepted outcomes of climate change studies using this downscaling technique need reconsideration
Selection trace from runs of homozygosity in French dairy sheep
No full textRuns of homozygosity (ROH) are contiguous homozygous segments of the genome where the haplotypes inherited from each parent are identical. Currently, inbreeding estimated from ROH is considered a powerful approach to distinguish between recent,potentially harmful, from ancient inbreeding, potentially beneficial. Accordingly, inbreeding based on ROH can help to improve the understanding of inbreeding
depression. The occurrence of ROH is not randomly distributed across the genome, and islands of ROH across a large number of animals may be the result of selective pressure. The objective of this study is to evaluate whether ROH can be used to explore signatures of selection in French dairy sheep. The data set available included animals from various breeds and subpopulations: Basco-Béarnaise breed (BB); Manech Tête Noire breed (MTN); Manech Tête Rousse breed (MTR); Lacaune Confederation subpopulation (LACCon); and Lacaune Ovitest subpopulation (LACOvi). Animals were genotyped with the Illumina OvineSNP50 BeadChip. After applying filtering criteria, the genomic data included 38,287 autosomal SNPs distributed across 26 chromosomes and 8,700 individuals. One island of ROH was detected on autosome 6 in the same genomic position across animals (between 30 – 40 Mb). Wright’s differentiation coefficients for two SNPs within this island of ROH were high (0.67 – 0.68). The linkage disequilibrium between both SNPs was also elevated (0.98). The divergence in allele frequencies in those SNPs grouped BB, MTN and MTR breeds in one cluster, and LACCon and LACOvi subpopulations in another cluster. The closest candidate gene is NCAPG-LCORL, which has been reported to be under positive selection and suggested to control height and stature in sheep, as well as growth and feed efficiency in cattle. These findings contribute to the understanding of the effects of selection in shaping the sheep genome
Point-of-need dna testing for detection of foodborne pathogenic bacteria
No full textFoodborne pathogenic bacteria present a crucial food safety issue. Conventional diagnostic methods are time-consuming and can be only performed on previously produced food. The advancing field of point-of-need diagnostic devices integrating molecular methods, biosensors, microfluidics, and nanomaterials offers new avenues for swift, low-cost detection of pathogens with high sensitivity and specificity. These analyses and screening of food items can be performed during all phases of production. This review presents major developments achieved in recent years in point-of-need diagnostics in land-based sector and sheds light on current challenges in achieving wider acceptance of portable devices in the food industry. Particular emphasis is placed on methods for testing nucleic acids, protocols for portable nucleic acid extraction and amplification, as well as on the means for low-cost detection and read-out signal amplification