Targeted LC-MS/MS-based metabolomics and lipidomics on limited hematopoietic stem cell numbers

Metabolism is important for the regulation of hematopoietic stem cells (HSCs) and drives cellular fate. Due to the scarcity of HSCs, it has been technically challenging to perform metabolome analyses gaining insight into HSC metabolic regulatory networks. Here, we present two targeted liquid chromatography–mass spectrometry approaches that enable the detection of metabolites after fluorescence-activated cell sorting when sample amounts are limited. One protocol covers signaling lipids and retinoids, while the second detects tricarboxylic acid cycle metabolites and amino acids. For complete details on the use and execution of this protocol, please refer to Schönberger et al. (2022)

Theoretical insight on the LK-99 material

Two recent preprints in physics archive (arXiv) have called the attention as they claim experimental evidence that a Cu-substituted apatite material (called LK-99) exhibits superconductivity at room temperature and pressure. If this proves to be true, LK-99 will be the holy grail of superconductors. In this work, we used Density-Functional Theory calculations to elucidate some key features of the electronic structure of LK-99. Although some aspects of our calculations are preliminary, we found that: i) in the ground state of the material the ferromagnetic and antiferromagnetic configurations are practically degenerated, ii) the material is metallic, iii) the Cu atoms seem to be hosts in the lattice with not covalent bonds to other atoms and supporting almost flat bands around the Fermi level, and iv) the electron-phonon coupling of these flat bands seems to be dramatically large

Nanoparticles assembled from mixtures of whey protein isolate and soluble soybean polysaccharides. Structure, interfacial behavior and application on emulsions subjected to freeze-thawing

In this article, the freeze-thaw stability of emulsions prepared with nanoparticles assembled from mixtures of whey protein isolate (WPI, 2.0% w/w)and soluble soybean polysaccharides (SSPS, 0.5% w/w)was assessed. The assembly was performed by pH adjustment to 3.0 without and with heating (90 °C, 15 min). Moreover, the order of addition of SSPS to proteins, before or after heating, was also studied. The complexes were characterized by dynamic light scattering, turbidity, non-sedimentable protein content, aromatic surface hydrophobicity (H 0 ), interfacial tension and interfacial rheology measurements at the oil/water interface. In all cases, the dispersions evidenced slightly-positive ζ-potential values due to electrostatic associative interactions between proteins and SSPS. Moreover, the complexation increased the particle size, the interfacial activity and the non-sedimentable protein content. Oil-in-water emulsions (30% w/w sunflower oil)prepared with unheated WPI/SSPS mixtures were more stable to freeze-thawing (−18 °C, 72 h; 20 °C, 2 h)respect to those prepared with WPI alone. When SSPS was added to previously heated proteins, the resultant emulsions also evidenced a high freeze-thaw stability. The large sedimentable species, which contributed to form a film of high viscoelasticity, could stabilize the emulsions by a Pickering mechanism. However, when SSPS and WPI were heated together, the resultant emulsions exhibited a low freeze-thaw stability due to a combination of poor emulsification ability and limited interfacial adsorption of large particles. The results of this article might have important implications in the preparation of highly acidic emulsion-based products resistant to freeze-thaw treatments.Fil: Cabezas, Dario Marcelino. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pascual, Guido N.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palazolo, Gonzalo Gastón. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The chemistry of H2NC in the interstellar medium and the role of the C + NH3 reaction

We carried out an observational search for the recently discovered molecule H2NC, and its more stable isomer H2CN, toward eight cold dense clouds (L1544, L134N, TMC-2, Lupus-1A, L1489, TMC-1 NH3, L1498, and L1641N) and two diffuse clouds (B0415+379 and B0355+508) in an attempt to constrain its abundance in different types of interstellar regions and shed light on its formation mechanism. We detected H2NC in most of the cold dense clouds targeted, 7 out of 8, while H2CN was only detected in 5 out of 8 clouds. The column densities derived for both H2NC and H2CN are in the range 1e11-1e12 cm-2 and the abundance ratio H2NC/H2CN varies between 0.51 and >2.7. The metastable isomer H2NC is therefore widespread in cold dense clouds where it is present with an abundance similar to that of H2CN. We did not detect either H2NC or H2CN in any of the two diffuse clouds targeted, which does not allow to shed light on how the chemistry of H2NC and H2CN varies between dense and diffuse clouds. We found that the column density of H2NC is correlated with that of NH3, which strongly suggests that these two molecules are chemically linked, most likely ammonia being a precursor of H2NC through the C + NH3 reaction. We performed electronic structure and statistical calculations which show that both H2CN and H2NC can be formed in the C + NH3 reaction through two different channels involving two different transition states which lie very close in energy. The predicted product branching ratio H2NC/H2CN is very method dependent but values between 0.5 and 0.8 are the most likely ones. Therefore, both the astronomical observations and the theoretical calculations support that the reaction C + NH3 is the main source of H2NC in interstellar clouds.Comment: Accepted for publication in A&

Nanoparticles assembled from mixtures of whey protein isolate and soluble soybean polysaccharides. Structure, interfacial behavior and application on emulsions subjected to freeze-thawing

In this article, the freeze-thaw stability of emulsions prepared with nanoparticles assembled from mixtures of whey protein isolate (WPI, 2.0% w/w)and soluble soybean polysaccharides (SSPS, 0.5% w/w)was assessed. The assembly was performed by pH adjustment to 3.0 without and with heating (90 °C, 15 min). Moreover, the order of addition of SSPS to proteins, before or after heating, was also studied. The complexes were characterized by dynamic light scattering, turbidity, non-sedimentable protein content, aromatic surface hydrophobicity (H 0 ), interfacial tension and interfacial rheology measurements at the oil/water interface. In all cases, the dispersions evidenced slightly-positive ζ-potential values due to electrostatic associative interactions between proteins and SSPS. Moreover, the complexation increased the particle size, the interfacial activity and the non-sedimentable protein content. Oil-in-water emulsions (30% w/w sunflower oil)prepared with unheated WPI/SSPS mixtures were more stable to freeze-thawing (−18 °C, 72 h; 20 °C, 2 h)respect to those prepared with WPI alone. When SSPS was added to previously heated proteins, the resultant emulsions also evidenced a high freeze-thaw stability. The large sedimentable species, which contributed to form a film of high viscoelasticity, could stabilize the emulsions by a Pickering mechanism. However, when SSPS and WPI were heated together, the resultant emulsions exhibited a low freeze-thaw stability due to a combination of poor emulsification ability and limited interfacial adsorption of large particles. The results of this article might have important implications in the preparation of highly acidic emulsion-based products resistant to freeze-thaw treatments.Fil: Cabezas, Dario Marcelino. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pascual, Guido N.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palazolo, Gonzalo Gastón. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Antioxidant and Emulsifying Properties of Modified Sunflower Lecithin by Fractionation with Ethanol-Water Mixtures

Lecithins are a mixture of acetone insoluble phospholipids, containing mainly phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidic acid (PA), and other minor substances such as carbohydrates and triglycerides [1-3]. The production of sunflower oil in Argentina, is of utmost importance from an economic point of view [4]. In this country, sunflower lecithin could represent an alternative to soybean lecithin because it is considered a non-GMO product, which is in accordance with the preference of some consumersFil: Cabezas, Dario Marcelino. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Guiotto, Estefania Nancy. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Diehl, Bernd W. K.. No especifíca;Fil: Tomás, Mabel Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

A new protonated molecule discovered in TMC-1: HCCNCH+

In recent years we have seen an important increase in the number of protonated molecules detected in cold dense clouds. Here we report the detection in TMC-1 of HCCNCH+, the protonated form of HCCNC, which is a metastable isomer of HC3N. This is the first protonated form of a metastable isomer detected in a cold dense cloud. The detection was based on observations carried out with the Yebes 40m and IRAM 30m telescopes, which revealed four harmonically related lines. We derive a rotational constant B = 4664.431891 +/- 0.000692 MHz and a centrifugal distortion constant D = 519.14 +/- 4.14 Hz. From a high-level ab initio screening of potential carriers we confidently assign the series of lines to the ion HCCNCH+. We derive a column density of (3.0 +/- 0.5)e10 cm-2 for HCCNCH+, which results in a HCCNCH+/HCCNC abundance ratio of 0.010 +/- 0.002. This value is well reproduced by a state-of-the-art chemical model, which however is subject to important uncertainties regarding the chemistry of HCCNCH+. The observational and theoretical status of protonated molecules in cold dense clouds indicate that there exists a global trend in which protonated-to-neutral abundance ratios MH+/M increase with increasing proton affinity of the neutral M, although if one restricts to species M with high proton affinities (>700 kJ/mol), MH+/M ratios fall in the range 0.001-0.1, with no apparent correlation with proton affinity. We suggest various protonated molecules that are good candidates for detection in cold dense clouds in the near future.Comment: Accepted for publication in A&A Letter

Determinação da aptidão biogeofísica do território EUROACE para a utilização agroflorestal

É consensual que a escolha dos usos mais adequados às aptidões edafo-climáticas, complementada com critérios socioeconómicos, promove uma utilização sustentável dos espaços rurais. Existem, no entanto, diferentes metodologias utilizadas para a definição da capacidade e potencialidade do solo para a implementação de usos agroflorestais ou manutenção de ecossistemas naturais e seminaturais, nomeadamente culturas agrícolas, povoamentos florestais, territórios agro-silvo-pastoris e áreas prioritárias para a conservação da natureza. Muitas dessas metodologias recorrem a sistemas de apoio à decisão, baseados na análise espacial multicritério. Neste estudo pretendeu-se determinar os diferentes níveis de aptidão para a utilização agroflorestal no território transfronteiriço que abrange o Alentejo, Extremadura e o Centro (Euro-região EUROACE). Para o efeito recorreu-se a um conjunto de variáveis edáficas e topográficas. Foram igualmente incorporadas as condicionantes legais e a ocupação do solo. A avaliação da aptidão foi efetuada com recurso ao método de análise espacial multicritério Analytic Hierarchy Process (AHP). O resultado obtido com esta metodologia, confrontado com a matriz de uso existente, permite identificar as áreas onde a ocupação e gestão está de acordo com a aptidão do espaço, bem como as áreas onde o uso deverá ser alvo de uma reconversão ou apenas a uma alteração de modo de gestão