Production and characterization of two medium-chain-length polydroxyalkanoates by engineered strains of Yarrowia lipolytica

Background: The oleaginous yeast Yarrowia lipolytica is an organism of choice for the tailored production of various compounds such as biofuels or biopolymers. When properly engineered, it is capable of producing medium-chain-length polyhydroxyalkanoate (mcl-PHA), a biobased and biodegradable polymer that can be used as bioplastics or biopolymers for environmental and biomedical applications.Results: This study describes the bioproduction and the main properties of two different mcl-PHA polymers. We generated by metabolic engineering, strains of Y. lipolytica capable of accumulating more than 25% (g/g) of mcl-PHA polymers. Depending of the strain genetic background and the culture conditions, we produced (i) a mcl-PHA homopolymer of 3-hydroxydodecanoic acids, with a mass-average molar mass (M-w) of 316,000 g/mol, showing soft thermoplastic properties with potential applications in packaging and (ii) a mcl-PHA copolymer made of 3-hydroxyoctanoic (3HO), decanoic (3HD), dodecanoic (3HDD) and tetradecanoic (3TD) acids with a M-w of 128,000 g/mol, behaving like a thermoplastic elastomer with potential applications in biomedical material.Conclusion: The ability to engineer Y. lipolytica to produce tailored PHAs together with the range of possible applications regarding their biophysical and mechanical properties opens new perspectives in the field of PHA bioproduction

Comparative analysis of morphometric traits of farmed sugar kelp and skinny kelp, Saccharina spp., strains from the Northwest Atlantic

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Umanzor, S., Li, Y., Bailey, D., Augyte, S., Huang, M., Marty-Rivera, M., Jannink, J., Yarish, C., & Lindell, S. Comparative analysis of morphometric traits of farmed sugar kelp and skinny kelp, Saccharina spp., strains from the Northwest Atlantic. Journal of the World Aquaculture Society, (2021), https://doi.org/10.1111/jwas.12783.Our team has initiated a selective breeding program for regional strains of sugar kelp, Saccharina latissima, to improve the competitiveness of kelp farming in the United States. Within our breeding program, we also include an endemic putative species, Saccharina angustissima, locally referred to as skinny kelp. We crossed uniclonal gametophyte cultures derived from 37 wild‐collected blades representing five sugar kelp strains and one skinny kelp strain to produce 104 unique crosses. Each cross was outplanted on a near‐shore research farm located in the Gulf of Maine (GOM). After the first farming season, our results indicated that sugar kelp and skinny kelp were interfertile, and produced mature and reproductively viable sporophytes. Morphological traits of individual blades varied depending on the parental contribution (sugar vs. skinny), with significant differences found in progeny blade length, width, thickness, and in stipe length and diameter. Despite these differences, wet weight and blade density per plot showed no statistical differences regardless of the cross. Given their published genetic similarity and their interfertility shown here, S. angustissima and S. latissima may not be different species, and may each contribute genetic diversity to breeding programs aimed at meeting ocean farming and market needs.Funding was provided by the U.S. Department of Energy, ARPAe MARINER project contract number DE‐AR0000915 and DE‐AR0000911, AgCore Technologies of Rhode Island, and the Massachusetts Clean Energy Center, AmplifyMass Program

Mapping domain junctions using 4D-STEM: toward controlled properties of epitaxially grown transition metal dichalcogenide monolayers

Epitaxial growth has become a promising route to achieve highly crystalline continuous two-dimensional layers. However, high-quality layer production with expected electrical properties is still challenging due to the defects induced by the coalescence between imperfectly aligned domains. In order to control their intrinsic properties at the device scale, the synthesized materials should be described as a patchwork of coalesced domains. Here, we report multi-scale and multistructural analysis on highly oriented epitaxial WS$_2$ and WSe$_2$ monolayers using scanning transmission electron microscopy (STEM) techniques. Characteristic domain junctions are first identified and classified based on the detailed atomic structure analysis using aberration corrected STEM imaging. Mapping orientation, polar direction and phase at the micrometer scale using four-dimensional STEM enabled to access the density and the distribution of the specific domain junctions. Our results validate a readily applicable process for the study of highly oriented epitaxial transition metal dichalcogenides, providing an overview of synthesized materials from large scale down to atomic scale with multiple structural information.Comment: 22 pages, 6 figures and Supplementary Informatio

Spécification d'exigences physico-physiologiques d'interaction homme-machine en ingénierie système

10 pagesNational audienceLes travaux exploratoires relatés dans le présent article portent sur la spécification d'exigences physico-physiologiques mesurables afin de mieux prendre en compte ce type de facteurs humains en ingénierie d'un système technique contrôlé par un humain. Le cas d'étude qui sert de fil conducteur tout au long de cet article est celui du contrôle par divers opérateurs d'un mécanisme de sécurisation satisfaisant une exigence opérationnelle de fermeture verrouillée de la porte d'accès à un équipement lors de la clôture d'une intervention de maintenance pour remise en condition opérationnelle d'un appareil. Ce processus de spécification combine dans un premier temps un cadre de Modélisation Système avec celui Mathématique et Computationnel de la Physiologie Intégrative . Cette spécification d'une interaction de perception est vérifiée dans un deuxième temps par exécution de modèles "SysML" interopérant avec des modèles physico-physiologiques en ingénierie d'un système support de maintenance dans notre cas d'étude

Le Musée de l'histoire de l'immigration à Paris: une collection et un musée en devenir

Globalization and the emergence of political issues in the European Union have propelled the topic of immigration into the center of the current political climate. In this contemporary context, museums that are focused on immigration are gaining more importance due to the impetus for preserving and providing visibility for the heritage of immigrants. In Paris during October 2007 the Cité nationale de l'Histoire de l'Immigration (CNHI) opened its doors but in 2013 it changed its name to Musée de l'histoire de l'immigration (MHI). The museum presents a historical and cultural approach to immigration as well as displaying contemporary works of art that deal with the theme of immigration. In this paper we will analyze how this museum is an attempt to integrate the History of immigration as a national heritage.Com a globalização e o surgimento da Comunidade Europeia, a questão das migrações se apresenta no centro das preocupações políticas mundiais contemporâneas. E nesse contexto histórico de países de imigração ou de emigração organizam-se os museus de estudos das migrações que pertencem à categoria dos museus de história e de sociedade. Em outubro de 2007, é criada, em Paris, a Cité nationale de l'Histoire de l'Immigration (CNHI) que desde 2013 passou a se chamar Musée de l'histoire de l'immigration (MHI): um museu que apresenta ao público uma abordagem histórica e cultural da imigração assim como obras de arte contemporânea que tratam do tema. Neste artigo, bucaremos compreender como este museu constitui uma tentativa de reconhecimento do patrimônio da imigração como um patrimônio nacional.Avec la mondialisation et l'émergence de nouvelles politiques d'immigration dans la Communauté Européenne, la question des migrations est centrale dans le monde politique d'aujourd'hui. C'est dans ce contexte historique de pays d'immigration ou d'émigration que se met en place et s'organise l'étude des musées d'immigration qui appartiennent à la catégorie des musées d'histoire et de société. En France, la Cité nationale de l'Histoire de l'Immigration, qui a ouvert ses portes en octobre 2007, depuis 2013 Musée de l'histoire de l'immigration (MHI), se distingue, dans ce contexte mondial, par l'originalité de son projet et les discussions qu'il suscite dans divers domaines (aussi bien dans le milieu académique que dans les réseaux d'associations qui s'occupent des immigrés en France). Le musée présente au public une approche historique et culturelle de l'immigration ainsi que des œuvres d'art contemporain sur ce sujet. Dans cet article, on s'interrogera sur comment ce musée constitue une tentative de reconnaître le patrimoine de l'immigration comme un patrimoine national

New DArT markers for oat provide enhanced map coverage and global germplasm characterization

BACKGROUND: Genomic discovery in oat and its application to oat improvement have been hindered by a lack of genetic markers common to different genetic maps, and by the difficulty of conducting whole-genome analysis using high-throughput markers. This study was intended to develop, characterize, and apply a large set of oat genetic markers based on Diversity Array Technology (DArT). RESULTS: Approximately 19,000 genomic clones were isolated from complexity-reduced genomic representations of pooled DNA samples from 60 oat varieties of global origin. These were screened on three discovery arrays, with more than 2000 polymorphic markers being identified for use in this study, and approximately 2700 potentially polymorphic markers being identified for use in future studies. DNA sequence was obtained for 2573 clones and assembled into a non-redundant set of 1770 contigs and singletons. Of these, 705 showed highly significant (Expectation < 10E-10) BLAST similarity to gene sequences in public databases. Based on marker scores in 80 recombinant inbred lines, 1010 new DArT markers were used to saturate and improve the 'Kanota' × 'Ogle' genetic map. DArT markers provided map coverage approximately equivalent to existing markers. After binning markers from similar clones, as well as those with 99% scoring similarity, a set of 1295 non-redundant markers was used to analyze genetic diversity in 182 accessions of cultivated oat of worldwide origin. Results of this analysis confirmed that major clusters of oat diversity are related to spring vs. winter type, and to the presence of major breeding programs within geographical regions. Secondary clusters revealed groups that were often related to known pedigree structure. CONCLUSION: These markers will provide a solid basis for future efforts in genomic discovery, comparative mapping, and the generation of an oat consensus map. They will also provide new opportunities for directed breeding of superior oat varieties, and guidance in the maintenance of oat genetic diversity

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe