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Hybrid complex coacervate
No full textUnderwater adhesion represents a huge technological challenge as the presence of water compromises the performance of most commercially available adhesives. Inspired by natural organisms, we have designed an adhesive based on complex coacervation, a liquid-liquid phase separation phenomenon. A complex coacervate adhesive is formed by mixing oppositely charged polyelectrolytes bearing pendant thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) chains. The material fully sets underwater due to a change in the environmental conditions, namely temperature and ionic strength. In this work, we incorporate silica nanoparticles forming a hybrid complex coacervate and investigate the resulting mechanical properties. An enhancement of the mechanical properties is observed below the PNIPAM lower critical solution temperature (LCST): this is due to the formation of PNIPAM-silica junctions, which, after setting, contribute to a moderate increase in the moduli and in the adhesive properties only when applying an ionic strength gradient. By contrast, when raising the temperature above the LCST, the mechanical properties are dominated by the association of PNIPAM chains and the nanofiller incorporation leads to an increased heterogeneity with the formation of fracture planes at the interface between areas of different concentrations of nanoparticles, promoting earlier failure of the network-an unexpected and noteworthy consequence of this hybrid system.</p
Variance estimates are similar using pedigree or genomic relationships with or without the use of metafounders or the algorithm for proven and young animals1
No full textWith an increase in the number of animals genotyped there has been a shift from using pedigree relationship matrices (A) to genomic ones. As the use of genomic relationship matrices (G) has increased, new methods to build or approximate G have developed. We investigated whether the way variance components are estimated should reflect these changes. We estimated variance components for maternal sow traits by solving with restricted maximum likelihood, with four methods of calculating the inverse of the relationship matrix. These methods included using just the inverse of A (A-1), combining A-1 and the direct inverse of G (HDIRECT-1), including metafounders (HMETA-1), or combining A-1 with an approximated inverse of G using the algorithm for proven and young animals (HAPY-1). There was a tendency for higher additive genetic variances and lower permanent environmental variances estimated with A-1 compared with the three H-1 methods, which supports that G-1 is better than A-1 at separating genetic and permanent environmental components, due to a better definition of the actual relationships between animals. There were limited or no differences in variance estimates between HDIRECT-1, HMETA-1, and HAPY-1. Importantly, there was limited differences in variance components, repeatability or heritability estimates between methods. Heritabilities ranged between <0.01 to 0.04 for stayability after second cycle, and farrowing rate, between 0.08 and 0.15 for litter weight variation, maximum cycle number, total number born, total number still born, and prolonged interval between weaning and first insemination, and between 0.39 and 0.44 for litter birth weight and gestation length. The limited differences in heritabilities suggest that there would be very limited changes to estimated breeding values or ranking of animals across models using the different sets of variance components. It is suggested that variance estimates continue to be made using A-1, however including G-1 is possibly more appropriate if refining the model, for traits that fit a permanent environmental effect.</p
Marine Sediments Illuminate Chlamydiae Diversity and Evolution
No full textThe bacterial phylum Chlamydiae is so far composed of obligate symbionts of eukaryotic hosts. Well known for Chlamydiaceae, pathogens of humans and other animals, Chlamydiae also include so-called environmental lineages that primarily infect microbial eukaryotes. Environmental surveys indicate that Chlamydiae are found in a wider range of environments than anticipated previously. However, the vast majority of this chlamydial diversity has been underexplored, biasing our current understanding of their biology, ecological importance, and evolution. Here, we report that previously undetected and active chlamydial lineages dominate microbial communities in deep anoxic marine sediments taken from the Arctic Mid-Ocean Ridge. Reaching relative abundances of up to 43% of the bacterial community, and a maximum diversity of 163 different species-level taxonomic units, these Chlamydiae represent important community members. Using genome-resolved metagenomics, we reconstructed 24 draft chlamydial genomes, expanding by over a third the known genomic diversity in this phylum. Phylogenomic analyses revealed several novel clades across the phylum, including a previously unknown sister lineage of the Chlamydiaceae, providing new insights into the origin of pathogenicity in this family. We were unable to identify putative eukaryotic hosts for these marine sediment chlamydiae, despite identifying genomic features that may be indicative of host-association. The high abundance and genomic diversity of Chlamydiae in these anoxic marine sediments indicate that some members could play an important, and thus far overlooked, ecological role in such environments and may indicate alternate lifestyle strategies. Dharamshi et al. find abundant, diverse, and active Chlamydiae in deep anoxic marine sediments. Using metagenomics, chlamydial genomes are obtained that form several new clades. Analyses of these genomes provide new insights into the evolution and host association of the Chlamydiae phylum, indicating that some are not symbionts of eukaryotic hosts.</p
Stochastic-dynamic modelling of farm-level investments under uncertainty
No full textIn the light of uncertainties, high initial costs, and temporal managerial flexibility, the real options approach has gained interest as a valuation tool for different types of natural resources management problems. Yet, neither real options valuation method excels under consideration of variability of resource endowments, returns-to-scale and predefined sizes of options. We fill the methodological gap by developing a method based on Monte Carlo simulation, scenario tree reduction, and stochastic programming that is advantageous for valuing real options where timing, scale and interactions among constraints and alternatives matter. The method advances in straightforward conversion of deterministic programming applications based on the classical net present value approach into a real options framework, and in introducing complexity into existing real options models. We illustrate the method with a case study featuring investment options regarding the adoption, coppicing, and conversion of perennial biomass energy production systems.</p
Towards breeding thrips-resistant varieties in Capsicum
No full textThrips are small insects but a major pest in pepper cultivation worldwide. They are difficult to control because of their high reproductive rate, short life cycle, cryptic behaviour and their wide host range. Protective measures such as chemical and biological control are used to prevent thrips outbreaks in crops, but these are only partially effective. Therefore, host plant resistance is a desired trait for pepper growers. Previously, thrips-resistant pepper accessions were identified. The aim of this thesis is to further characterize the resistance mechanism of the resistant pepper accession CGN16975, and to study its potential as a source for breeding thrips-resistant Capsicum varieties. The gene or genes on chromosome 6 that contribute to thrips resistance were fine mapped and a multidisciplinary approach was used to select candidate genes. Furthermore the role of metabolites in this resistance mechanism was studied. Altogether, the work in this thesis contributes to protection of pepper against thrips, and shows that the resistance mechanism in CGN16975 can be used as a source for breeding thrips-resistant Capsicum varieties
A lipase fusion feasts on fat
No full textThe enzyme lipoprotein lipase (LPL) is responsible for breaking down triglycerides in the blood. Mutations in LPL cause a rare but debilitating disorder characterized by excessive plasma triglyceride levels for which treatment options are limited. Nimonkar et al. now present a fusion protein between LPL and its physiological transporter GBIHBP1 that is highly active and largely resistant to physiological inhibitors of LPL. Injecting this fusion protein effectively lowers plasma triglycerides in mice and represents a promising new approach for lowering triglycerides in patients with familial chylomicronemia syndrome.</p
Options to Reform the European Union Legislation on GMOs: Risk Governance
No full textHere, we discuss options to reform the EU genetically modified organism (GMO) regulatory framework, to make risk assessment and decision-making more consistent with scientific principles, and to lay the groundwork for international coherence. We discussed the scope and definitions in a previous article and, thus, here we focus on the procedures for risk assessment and risk management.</p
The phenolic compounds, tocopherols, and phytosterols in the edible oil of guava (Psidium guava) seeds obtained by supercritical CO<sub>2</sub> extraction
No full textAn edible oil was obtained from guava seeds by supercritical CO2 extraction. The oil was characterized by its fatty acid composition, physicochemical properties, and the contents of phenolic, miscellaneous, phytosterol, and tocopherol compounds. The oil, obtained with a yield of 8.6 ± 1.2 g oil/100 g guava seeds, had a high content of linoleic acid (78.5 %, w/w), followed by that of oleic acid (13.8 %, w/w). The guava seed oil had physicochemical properties comparable to those published in previous research, except for the low stability to oxidation. The chromatographic profile of the phenolic and miscellaneous compounds was dominated by vanillin (9.6 ± 0.3 mg/100 g oil) and cinnamaldehyde (9.4 ± 0.2 mg/100 g oil), followed by vanillic acid (3.9 ± 0.4 mg/100 g oil), cinnamic acid (2.4 ± 0.1 mg/100 g oil), and minor amounts of other phenolic aldehydes. Among the phytosterols and tocopherols, β-sitosterol (1048.9 ± 48.4 mg/100 g oil) and γ-tocopherol (82.6 ± 3.7 mg/100 g oil) were the most abundant. The low oxidative stability of the oil compared to that published in previous reports might reflect the high complexity of this matrix. This oil might have applications, directly or after blending with more stable edible oils.</p
Sustainability challenges and innovations in the Dutch egg sector
No full textWhile global demand for eggs is increasing, concerns are being raised about the environmental, economic and social impact of egg production. Efforts to address these sustainability concerns can, however, result in trade-offs. To enhance a transparent debate about future options and limitations in the egg sector, insight is needed in environmental, economic and social sustainability challenges as well as in potential trade-offs involved in addressing these challenges. Based on interviews with 24 stakeholders and supported by scientific literature, this paper presents an overview of current sustainability challenges and trade-offs in the Dutch egg sector. Moreover, the paper provides an overview of innovations suggested by stakeholders that can help to address the identified sustainability challenges, and describes current limitations for the implementation of these innovations. Innovations identified were related to animal health and welfare (n = 13), housing systems (n = 7), economy (n = 8), environment (n = 9), and organisation (n = 6). Stakeholders considered innovations to reduce particulate matter emissions as one with priority. In addition, controlling poultry red mite, approaches to translate costs for environmental investments to consumers, closing manure-feed cycles and improved collaboration in the chain were considered as important steps to address current sustainability challenges. Our results reveal the complex interactions between sustainability challenges in the egg sector and give insight in the different perspectives and considerations stakeholders have. Steps towards sustainable egg production therefore require multi-stakeholder dialogue to find consensus and jointly identify so-called small wins, i.e. meaningful and feasible steps that can contribute to a more sustainable food system.</p