189 research outputs found
A novel RUNX1 mutation with ANKRD26 dysregulation is related to thrombocytopenia in a sporadic form of myelodysplastic syndrome
Aging is associated with a higher risk of developing malignant diseases, including myelodysplastic syndromes, clonal disorders characterised by chronic cytopenias (anaemia, neutropenia and thrombocytopenia) and abnormal cellular maturation. Myelodysplastic syndromes arising in older subjects are influenced by combinations of acquired somatic genetic lesions driving evolution from clonal haematopoiesis to myelodysplastic syndromes and from myelodysplastic syndromes to acute leukaemia. A different pattern of mutations has been identified in a small subset of myelodysplastic syndromes arising in young patients with familial syndromes. In particular, dysregulation of ANKRD26, RUNX1 and ETV6 genes plays a role in familial thrombocytopenia with predisposition to myelodysplastic syndromes and acute leukaemia. Whether these genes affect thrombopoiesis in sporadic myelodysplastic syndrome with thrombocytopenia is still undefined. Thirty-one myelodysplastic syndromes subjects and 27 controls subjects were investigated. Genomic DNA was used for mutation screening (ETV6, RUNX1, 5′UTR ANKRD26 genes). Functional studies were performed in the MEG-01-akaryoblastic cell line. We found four novel variants of RUNX1 gene, all in elderly myelodysplastic syndromes subjects with thrombocytopenia. Functional studies of the variant p.Pro103Arg showed no changes in RUNX1 expression, but the variant was associated with deregulated high transcriptional activity of ANKRD26 in MEG-01 cells. RUNX1 variant p.Pro103Arg was also associated with increased viability and reduced apoptosis of MEG-01, as well as impaired platelet production. Our findings are consistent with dysregulation of ANKRD26 in RUNX1 haploinsufficiency. Lack of repression of ANKRD26 expression may contribute to thrombocytopenia of subjects with sporadic myelodysplastic syndromes
Bombyx mori Silk Fibroin Regeneration in Solution of Lanthanide Ions: A Systematic Investigation
Silk Fibroin (SF) obtained from Bombyx mori is a very attractive biopolymer that can be useful for many technological applications, from optoelectronics and photonics to biomedicine. It can be processed from aqueous solutions to obtain many scaffolds. SF dissolution is possible only with the mediation of chaotropic salts that disrupt the secondary structure of the protein. As a consequence, recovered materials have disordered structures. In a previous paper, it was shown that, by modifying the standard Ajisawa’s method by using a lanthanide salt, CeCl3, as the chaotropic agent, it is possible to regenerate SF as a fibrous material with a very ordered structure, similar to that of the pristine fiber, and doped with Ce+3 ions. Since SF exhibits a moderate fluorescence which can be enhanced by the incorporation of organic molecules, ions and nanoparticles, the possibility of doping it with lanthanide ions could be an appealing approach for the development of new photonic systems. Here, a systematic investigation of the behavior of degummed SF in the presence of all lanthanide ions, Ln+3, is reported. It has been found that all lanthanide chlorides are chaotropic salts for solubilizing SF. Ln+3 ions at the beginning and the end of the series (La+3, Pr+3, Er+3, Tm+3, Yb+3, Lu+3) favor the reprecipitation of fibrous SF as already found for Ce+3. In most cases, the obtained fiber preserves the morphological and structural features of the pristine SF. With the exception of SF treated with La+3, Tm+3, and Lu+3, for all the fibers re-precipitated a concentration of Ln+3 between 0.2 and 0.4% at was measured, comparable to that measured for Ce+3-doped SF
Light-activated shape morphing and light-tracking materials using biopolymer-based programmable photonic nanostructures
Natural systems display sophisticated control of light-matter interactions at multiple length scales for light harvesting, manipulation, and management, through elaborate photonic architectures and responsive material formats. Here, we combine programmable photonic function with elastomeric material composites to generate optomechanical actuators that display controllable and tunable actuation as well as complex deformation in response to simple light illumination. The ability to topographically control photonic bandgaps allows programmable actuation of the elastomeric substrate in response to illumination. Complex three-dimensional configurations, programmable motion patterns, and phototropic movement where the material moves in response to the motion of a light source are presented. A “photonic sunflower” demonstrator device consisting of a light-tracking solar cell is also illustrated to demonstrate the utility of the material composite. The strategy presented here provides new opportunities for the future development of intelligent optomechanical systems that move with light on demand
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Generation of UV light from microstructural fibers pumped with a femtosecond 800 NM oscillator.
Microstructured fibers have been shown to be an excellent media for nonlinear optical interactions due to small core size, long interaction length and unusual dispersion properties. Supercontinuum generation with just oscillator pumping is one of the manifestations of such properties [l]. The supercontinuum is typically observed in the fundamental mode even in the multimode PCFs. Another interesting observation is the generation of distinct frequency bands when pumping the PCF at 1550 nm [2]. The color generation was observed in the visible region exiting the fiber in single higher-order modes different for each color. Here we report the observation of the upconversion of the femtosecond 800 nm pulses from a commercial Ti:Sapphire oscillator to the UV frequency range, Fig. 1. It is unambiguously observed that the nonlinear mechanism is distinct from that of the supercontinuum generation and the UV generation occurs starting from the higher-order mode at the fundamental wavelength and yielding a very high-order mode in the UV
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Control of visible harmonic generation using polarization in photonic crystal fibers
The polarization state of the input pulses to a segment of microstructured fiber controls the harmonic generation yielding specific frequencies depending on of the input state
Rough Fibrils Provide a Toughening Mechanism in Biological Fibers
Spider silk is a fascinating
natural composite material. Its combination
of strength and toughness is unrivalled in
nature, and as a result, it has gained considerable
interest from the medical, physics,
and materials communities. Most of this
attention has focused on the one to tens of
nanometer scale: predominantly the primary
(peptide sequences) and secondary (β sheets,
helices, and amorphous domains) structure, with some insights into tertiary structure (the
arrangement of these secondary structures) to describe the origins of the mechanical and
biological performance. Starting with spider silk, and relating our findings to collagen fibrils,
we describe toughening mechanisms at the hundreds of nanometer scale, namely, the fibril
morphology and its consequences for mechanical behavior and the dissipation of energy.
Under normal conditions, this morphology creates a nonslip fibril kinematics, restricting
shearing between fibrils, yet allowing controlled local slipping under high shear stress,
dissipating energy without bulk fracturing. This mechanism provides a relatively simple target
for biomimicry and, thus, can potentially be used to increase fracture resistance in synthetic
materials
Functional material features of Bombyx mori silk light versus heavy chain proteins
Bombyx mori (BM) silk fibroin is composed of two different subunits; heavy chain and light chain fibroin linked by a covalent disulphide bond. Current methods of separating the two silk fractions is complicated and produces inadequate quantities of the isolated components for the study of the individual light and heavy chain silks with respect to new materials. We report a simple method of separating silk fractions using formic acid. The formic acid treatment partially releases predominately the light chain fragment (soluble fraction) and then the soluble fraction and insoluble fractions can be converted into new materials. The regenerated original (total) silk fibroin and the separated fractions (soluble vs. insoluble) had different molecular weights and showed distinctive pH stabilities against aggregation/precipitation based on particle charging. All silk fractions could be electrospun to give fibre mats with viscosity of the regenerated fractions being the controlling factor for successful electrospinning. The silk fractions could be mixed to give blends with different proportions of the two fractions to modify the diameter and uniformity of the electrospun fibres formed. The soluble fraction containing the light chain was able to modify the viscosity by thinning the insoluble fraction containing heavy chain fragments, perhaps analogous to its role in natural fibre formation where the light chain provides increased mobility and the heavy chain producing shear thickening effects. The simplicity of this new separation method should enable access to these different silk protein fractions and accelerate the identification of methods, modifications and potential applications of these materials in biomedical and industrial applications
Structural Characterization of Minor Ampullate Spidroin Domains and Their Distinct Roles in Fibroin Solubility and Fiber Formation
10.1371/journal.pone.0056142PLoS ONE82
Microbial Diversity in the Midguts of Field and Lab-Reared Populations of the European Corn Borer Ostrinia nubilalis
Background: Insects are associated with microorganisms that contribute to the digestion and processing of nutrients. The European Corn Borer (ECB) is a moth present world-wide, causing severe economical damage as a pest on corn and other crops. In the present work, we give a detailed view of the complexity of the microorganisms forming the ECB midgut microbiota with the objective of comparing the biodiversity of the midgut-associated microbiota and explore their potential as a source of genes and enzymes with biotechnological applications. Methodological/Principal Findings: A high-throughput sequencing approach has been used to identify bacterial species, genes and metabolic pathways, particularly those involved in plant-matter degradation, in two different ECB populations (field-collected vs. lab-reared population with artificial diet). Analysis of the resulting sequences revealed the massive presence of Staphylococcus warneri and Weissella paramesenteroides in the lab-reared sample. This enabled us to reconstruct both genomes almost completely. Despite the apparently low diversity, 208 different genera were detected in the sample, although most of them at very low frequency. By contrast, the natural population exhibited an even higher taxonomic diversity along with a wider array of cellulolytic enzyme families. However, in spite of the differences in relative abundance of major taxonomic groups, not only did both metagenomes share a similar functional profile but also a similar distribution of non-redundant genes in different functional categories. Conclusions/Significance: Our results reveal a highly diverse pool of bacterial species in both O. nubilalis populations, with major differences: The lab-reared sample is rich in gram-positive species (two of which have almost fully sequenced genomes) while the field sample harbors mainly gram-negative species and has a larger set of cellulolytic enzymes. We have found a clear relationship between the diet and the midgut microbiota, which reveals the selection pressure of food on the community of intestinal bacteria. © 2011 Belda et al.The research was funded by the Spanish Ministerio de Ciencia e Innovacion, under grant agreement CIT-010000-2008-5 and by a MICINN (Ministerio de Ciencia e Innovacion) TIN2009-12359 ArtBioCom project. Arnau Montagud acknowledges Generalitat Valenciana grant BFPI/2007/283. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Belda Cuesta, EA.; Pedrola, L.; Peretó Magraner, J.; Martinez Blanch, JF.; Montagud Aquino, A.; Navarro-Peris, E.; Urchueguía Schölzel, JF.... (2011). Microbial Diversity in the Midguts of Field and Lab-Reared Populations of the European Corn Borer Ostrinia nubilalis. PLoS ONE. 6(6):21751-21751. https://doi.org/10.1371/journal.pone.0021751S21751217516
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