Seed Yield and Biological Nitrogen Fixation for Historical Soybean Genotypes

Seed yield formation and biological nitrogen (N) fixation (BNF) were evaluated during the seed filling period (SFP) for historical soybean genotypes under contrasting N strategies. Overall, seed yield increased with the year of release, primarily associated with increments in the seed number component. The study showed that seed weight factor was maintained across decades regardless of the improvement in seed number. Nitrogen factor, evaluated as zero-N application via inorganic fertilizers versus high-N added, influenced seed yield via impacting seed weight factor. The latter plant trait improved with the high-N treatment, which was related to changes in the duration of the SFP rather than in the rate (seed biomass accumulation per day). The BNF parameter also reflected changes during the SFP related to the N treatment implemented, with high BNF (c.a. peak around 70-90%) under zero-N treatment, but still providing N via BNF at a lower rate (c.a. peak around 40-50%) for the high-N treatment. The latter demonstrated that the N fertilization reduced BNF by nearly 50% but did not completely inhibit this process. Thus, the zero-N plants counted on three sources of N to satisfy seed N demand: N-BNF, N-soil, and N-fertilizer. Lastly, the high-N treatment also positively impacted yields (+7 bu/a), which could potentially demonstrate a nitrogen limitation toward the end of the SFP for soybeans. Further testing will be performed during the next growing season to provide an improved yield and BNF characterization under different growing seasons (weather)

Magnetically responsive tropoelastin hydrogel as a platform for soft tissue regeneration applications

Publicado em "European Cells and Materials. ISSN 1473-2262. Vol. 33, Suppl. 2, 2017 (0006)"The natural polymer tropoelastin is a structural protein of ECM of tissues requiring elasticity as part of their function, including ligaments and tendons. Tropoelastin has an innate capacity of self-assembly into high-order structures, and together with elastic resilience, structural stability and bioactivity bring forth pleasant singularities in adopting it as a building block to fabricate hydrogels. Moreover, easy tailoring of properties can be attained via incorporation of specific components into the polymeric network, including magnetic nanoparticles (MNPs), which are beneficial for on-demand therapies. Thus, the main goal of this work consisted in developing a magnetically responsive tropoelastin (MagTro) hydrogel as a platform to study the response of tendon cells to a mechanical stimulus induced by application of an external magnetic field (EMF). For this purpose, to first produce hydrogels, a solution of recombinant human tropoelastin was first freeze-dried overnight inside a mould and then chemically cross-linked inside an open desiccator via vapour glutaraldehyde. Thereafter, MagTro hydrogels were obtained through in situ precipitation of MNPs by immersing tropoelastin hydrogels in FeCl2 and FeCl3 solution overnight and secondly by soaking them in NaOH. Hydrogels were then analysed morphologically by Scanning Electron Microscopy (SEM and Cryo-SEM). Enzyme-triggered degradation was studied after 72h at 37oC in a human neutrophil elastase solution. Hydrogels exhibited a quick magnetic responsiveness to an EMF (Fig.1). Interestingly, MagTro hydrogels exhibited smaller pores as observed by Cryo-SEM. This feature can be tuned according to different soft tissue requirements by controlling different parameters of the fabrication process. Additionally, the release of tropoelastin into solution decreased, which suggests the formation of a surface coating of MNPs on tropoelastin network, protecting the hydrogel from a faster degradation. Preliminary results also indicate that cultured cells are viable and spread at the surface of the hydrogel. The application of an EMF to cell-laden MagTro hydrogels will be further investigated. Overall, the streamlined fabrication of MagTro hydrogels was successfully attained and the hydrogel formulation represents a promising potential platform for soft tissue regeneration.The authors acknowledge to BEAM-Master Joint Mobility Project an EU Australian cooperation in Biomedical Engineering Grant Agreement, 2014-1843/001 001-CPT EU-ICI-ECP and to FCT–Fundação para a Ciência e a Tecnologia in the framework of FCT-POPH-FSE, RC-A PhD grant SFRH/BD/96593/2013 and MEG grant IF/00685/2012.info:eu-repo/semantics/publishedVersio

Effects of Nitrogen in Soybean Seed Quality Definition During Seed-Filling Period

During the seed filling period (SFP), parallel to the seed changes, translocation of assimilates and nutrients takes place from different plant organs to the seed in order to provide sufficient supply for the seed storage components (i.e., starch, oil, and protein) that ultimately will determine the seed quality. There are two processes that define the final seed weight in any crop: 1) the amount of dry mass deposited per unit of time (rate) and 2) the duration of this process from beginning of seed formation to physiological maturity. As seed number is defined, any source limitation during the SFP can affect the final weight and quality of the seeds. This study aims to investigate if nitrogen (N) is limiting potential seed weight and, in consequence, final seed yield as well as the characterization of the deposition of seed components (i.e., oil and protein) that define soybean seed quality among different N conditions and genotypic background

Simulated hypergravity induces changes in human tendon-derived cells: from cell morphology to gene expression

Gravity influences physical and biological processes, having an impact on development, as well as homeostasis of living systems. The musculoskeletal system is comprised of several mechano- responsive tissues and altered gravitational forces are known to influence distinct properties, including bone mineral density and skeletal muscle mass. This is particularly relevant in a near- weightlessness (microgravity) environment, which is found during spaceflight and, not less importantly, during bed resting. Over the years, several studies have been conducted under simulated conditions of altered gravity owing to the advances on ground-based facilities, such as bioreactors for microgravity / hypo-gravity (1g) studies. Interestingly, microgravity-induced alterations are comparable to tissue degeneration caused by disuse and ageing. In turn, exposing musculoskeletal tissues to hypergravity may constitute a way of simulating (over)loading or, eventually, to be used as a measure to rescue cell phenotype after exposure to near-weightlessness conditions. Different studies have focused on bone, cartilage and skeletal muscle, but effects on tendons and ligaments have been underappreciated. Therefore, we evaluated the influence of increasing g-levels (5g, 10g, 15g and 20g) and different hypergravity exposure periods (4 and 16 h) on the behaviour of human tendon- derived cells (hTDCs). For this purpose, hTDCs were exposed to simulated hypergravity conditions using the Large Diameter Centrifuge (LDC) from the European Space Research and Technology Centre (ESTEC, ESA, The Netherlands). Human TDCs cultured under standard conditions (1g, normogravity, Earth gravity force) were used as controls. The effects of hypergravity on the viability of hTDCs, as well as on the expression of tendon related markers at the gene level were evaluated. Simulated hypergravity resulted in a reduced cell content after 16 h independently of g-level, as determined by DNA quantification. Additionally, the different g-levels studied led to changes in cell and cytoskeleton morphology. Strikingly, a 16-hour period of exposure resulted in alterations of gene expression profiles. Overall, gene expression of tendon-related markers, including collagen types I (col1a1) and III (col3a1), scleraxis (scx), tenomodulin (tnmd), decorin (dcn) and tenascin (tnc), seemed to be increased upon hypergravity stimulation and in comparison to cells cultured under control conditions. Altogether, these results highlight that altered gravity, particularly simulated hypergravity, has an influence on the phenotype of tendon cells, opening new avenues for research focused on using altered gravity as a model for overloading-induced tendon tissue injury or as measure to rescue the phenotype of degenerated tendon cells. Acknowledgements The authors would like to thank ESA Education Office for Spin Your Thesis! 2016 programme. R.C-A acknowledges the PhD grant SFRH/BD/96593/2013 from FCT â Fundação para a Ciência e a Tecnologia. SFRH/BD/96593/2013 from FCT –Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Single cell analyses and machine learning define hematopoietic progenitor and HSC-like cells derived from human PSCs

Haematopoietic stem and progenitor cells (HSPCs) develop through distinct waves at various anatomical sites during embryonic development. The in vitro differentiation of human pluripotent stem cells (hPSCs) is able to recapitulate some of these processes, however, it has proven difficult to generate functional haematopoietic stem cells (HSCs). To define the dynamics and heterogeneity of HSPCs that can be generated in vitro from hPSCs, we exploited single cell RNA sequencing (scRNAseq) in combination with single cell protein expression analysis. Bioinformatics analyses and functional validation defined the transcriptomes of naïve progenitors as well as erythroid, megakaryocyte and leukocyte-committed progenitors and we identified CD44, CD326, ICAM2/CD9 and CD18 as markers of these progenitors, respectively. Using an artificial neural network (ANN), that we trained on a scRNAseq derived from human fetal liver, we were able to identify a wide range of hPSCs-derived HPSC phenotypes, including a small group classified as HSCs. This transient HSC-like population decreased as differentiation proceeded and was completely missing in the dataset that had been generated using cells selected on the basis of CD43expression. By comparing the single cell transcriptome of in vitro-generated HSC-like cells with those generated within the fetal liver we identified transcription factors and molecular pathways that can be exploited in the future to improve the in vitro production of HSCs

APP Processing Induced by Herpes Simplex Virus Type 1 (HSV-1) Yields Several APP Fragments in Human and Rat Neuronal Cells

Lifelong latent infections of the trigeminal ganglion by the neurotropic herpes simplex virus type 1 (HSV-1) are characterized by periodic reactivation. During these episodes, newly produced virions may also reach the central nervous system (CNS), causing productive but generally asymptomatic infections. Epidemiological and experimental findings suggest that HSV-1 might contribute to the pathogenesis of Alzheimer's disease (AD). This multifactorial neurodegenerative disorder is related to an overproduction of amyloid beta (Aβ) and other neurotoxic peptides, which occurs during amyloidogenic endoproteolytic processing of the transmembrane amyloid precursor protein (APP). The aim of our study was to identify the effects of productive HSV-1 infection on APP processing in neuronal cells. We found that infection of SH-SY5Y human neuroblastoma cells and rat cortical neurons is followed by multiple cleavages of APP, which result in the intra- and/or extra-cellular accumulation of various neurotoxic species. These include: i) APP fragments (APP-Fs) of 35 and 45 kDa (APP-F35 and APP-F45) that comprise portions of Aβ; ii) N-terminal APP-Fs that are secreted; iii) intracellular C-terminal APP-Fs; and iv) Aβ1-40 and Aβ1-42. Western blot analysis of infected-cell lysates treated with formic acid suggests that APP-F35 may be an Aβ oligomer. The multiple cleavages of APP that occur in infected cells are produced in part by known components of the amyloidogenic APP processing pathway, i.e., host-cell β-secretase, γ-secretase, and caspase-3-like enzymes. These findings demonstrate that HSV-1 infection of neuronal cells can generate multiple APP fragments with well-documented neurotoxic potentials. It is tempting to speculate that intra- and extracellular accumulation of these species in the CNS resulting from repeated HSV-1 reactivation could, in the presence of other risk factors, play a co-factorial role in the development of AD

Encephalopathy associated with autoimmune thyroid disease in patients with Graves' disease: clinical manifestations, follow-up, and outcomes

<p>Abstract</p> <p>Background</p> <p>The encephalopathy associated with autoimmune thyroid disease (EAATD) is characterized by neurological/psychiatric symptoms, high levels of anti-thyroid antibodies, increased cerebrospinal fluid protein concentration, non-specific electroencephalogram abnormalities, and responsiveness to the corticosteroid treatment in patients with an autoimmune thyroid disease. Almost all EAATD patients are affected by Hashimoto's thyroiditis (HT), although fourteen EAATD patients with Graves' disease (GD) have been also reported.</p> <p>Methods</p> <p>We have recorded and analyzed the clinical, biological, radiological, and electrophysiological findings and the data on the therapeutic management of all GD patients with EAATD reported so far as well as the clinical outcomes in those followed-up in the long term.</p> <p>Results</p> <p>Twelve of the fourteen patients with EAATD and GD were women. The majority of GD patients with EAATD presented with mild hyperthyroidism at EAATD onset or shortly before it. Active anti-thyroid autoimmunity was detected in all cases. Most of the patients dramatically responded to corticosteroids. The long term clinical outcome was benign but EAATD can relapse, especially at the time of corticosteroid dose tapering or withdrawal. GD and HT patients with EAATD present with a similar clinical, biological, radiological, and electrophysiological picture and require an unaffected EAATD management.</p> <p>Conclusions</p> <p>GD and HT equally represent the possible background condition for the development of EAATD, which should be considered in the differential diagnosis of all patients with encephalopathy of unknown origin and an autoimmune thyroid disease, regardless of the nature of the underlying autoimmune thyroid disease.</p