1,263 research outputs found
Innovative Microstructural Transformation upon CO2 Supercritical Conditions on Metal-Nucleobase Aerogel and Its Use as Effective Filler for HPLC Biomolecules Separation
This work contributes to enlightening the opportunities of the anisotropic scheme of non-covalent interactions present in supramolecular materials. It provides a top-down approach based on their selective disruption that herein has been employed to process a conventional microcrystalline material to a nanofibrillar porous material. The developed bulk microcrystalline material contains uracil-1-propionic acid (UPrOH) nucleobase as a molecular recognition capable building block. Its crystal structure consists of discrete [Cu(UPrO)2 (4,4′-bipy)2 (H2 O)] (4,4′-bipy=4,4′-bipyridine) entities held together through a highly anisotropic scheme of non-covalent interactions in which strong hydrogen bonds involving coordinated water molecules provide 1D supramolecular chains interacting between them by weaker interactions. The sonication of this microcrystalline material and heating at 45 °C in acetic acid–methanol allows partial reversible solubilization/recrystallization processes that promote the cross-linking of particles into an interlocked platelet-like micro-particles metal–organic gel, but during CO2 supercritical drying, the microcrystalline particles undergo a complete morphological change towards highly anisotropic nanofibers. This unprecedented top-down microstructural conversion provides a nanofibrillar material bearing the same crystal structure but with a highly increased surface area. Its usefulness has been tested for HPLC separation purposes observing the expected nucleobase complementarity-based separation.We thank the grant CTQ2017-87201-P funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” for financial support; and Generalidat Valenciana (Prometeo/2019/076). We thank the grant PID2019-108028GB-C22 and PID2019-108028GB-C21 funded by MCIN/AEI 10.13039/501100011033.We thank the grant FEDERPID2020-118422-GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” for financial support; and the Basque Government (Grupos IT908-16)
Trace Elements Distribution in Red Soils under Semiarid Mediterranean Environment
This study states the potential trace elements (TE’s) content of red soils located at the centre region of Spain, characterized by low rainfall and slight acidity over prolonged weathering periods. For this purpose, three soil profiles from a catena were described, sampled and analyzed. The most notable characteristics are the low organic matter content and the predominantly acidic pH. Illite and kaolinite are the predominant clay minerals. The fertility of the soils is sufficient to provide most of the nutrients required, with very suitable potassium levels. The geochemical characters of this soil are: only few elements remain almost invariable across the profiles and over time, however the majority of them were directly linked with the clay content. These soils are characterized by relatively low levels of some trace elements such as Sr (64.35 mg?kg–1), Ba (303.67 mg?kg–1) and Sc (13.14 mg?kg–1); high levels of other trace elements such as V (103.92 mg?kg–1), Cr (79.9 mg?kg–1), Cu (15.18 mg?kg–1), Hf (10.26 mg?kg–1), Ni (38 mg?kg–1) and Zr (337 mg?kg–1); while the levels for rare earth elements (REE’s) such as La (48.36 mg?kg–1), Ce (95.07 mg?kg–1), Th (13.33 mg?kg–1) and Nd (42.65 mg?kg–1) are significantly high. The distribution of mayor and trace elements was directly re- lated to weathering processes, parent material and anthropogenic activities
Zaluzania montagnifolia: essential oil composition and biological properties
The chemical composition of the seasonal essential oils (2015-2016) from the leaves and flowers of Zaluzania montagnifolia is presented. The chemical content of those oils showed quantitative and qualitative differences. Germacrene D (19.9-29.8%), camphor (12.4- 19.4%) and β-caryophyllene (13.7-18.5%) were the most abundant volatiles in the leaves. The essential oils from the flowers contained high amounts of camphor (32.7-37.2%) limonene (19.8-24.9%) and germacrene D (3.2-7.3%). All the seasonal essential oils showed a potent in vitro inhibition against HMG-CoA reductase. The essential oils from flowers (IC50, 40.5-55.1 μg mL-1) showed better inhibition properties than those of leaves (IC50, 84.4-123.5 μg mL-1). Camphor (IC50, 72.5 μg mL-1) and borneol (IC50, 84.4 μg mL-1) exerted a non-competitive inhibition on the enzyme. Additionally, the hydrodistillates exhibited antibacterial activity against the phytopathogenic Pseudomonas syringae pv. tabaci TBR2004 (MIC, 62.7-76.5 μg mL-1) P. syringae pv. tomato DC3000 (MIC, 45.4-50.4 μg mL-1) and P. syringae pv.phaseolicola NPS3121 (MIC, 26.7-31.9 μg mL-1). Germacrene D (MIC, 35.4-66.2 μg mL-1) and β-caryophyllene (MIC, 36.5-54.2 μg mL-1) were the strongest anti-Pseudomonas syringae agents
DISTRIBUCIÓN GEOGRÁFICA Y ECOLÓGICA DE LA FLORA AMENAZADA DE EXTINCIÓN EN LA ZONA ÁRIDA DEL ESTADO DE SAN LUIS POTOSÍ, MÉXICO
The objective of the present study is todetermine which of the endangered plant taxalisted in the 1994 Norma Oficial Mexicana(NOM-059-ECOL-1994) are present in thearid zones of San Luis Potosí and to analyze togeographical and ecological distributions ofthese taxa in the state, 29 species and 5varieties in 18 genera and 5 families are present,42% of the endangered species are found inrosette scrub, 33% in microphyllousshrublands, 20% in desert grassland and 5% incrassicaulous vegetation. The presence of 25 ofthe 29 endangered species was noted in thecorridor formed by the eastern slope of theSierra de Librillos and the western slope of theierra La Trinidad, an area which includes partsof the municipios of Matehuala, Villa deGuadalupe, Guadalcázar, Cerritos and VillaHidalgo. Many of these species are endemicand hence vulnerable to extinction.Ante la presencia en la zona árida del estado deSan Luis Potosí de especies de plantasconsideradas bajo algún tipo de riesgo, seplantearon como objetivos identificar cuáles delos taxa mencionados en la NOM-059-ECOL-1994 se encuentran en el área de estudio yanalizar su distribución geográfica y ecológica.Se localizaron cinco familias botánicas, 18géneros, 29 especies y cinco variedades, bajoalguna de las categorías de la Norma OficialMexicana (1994). En el matorral desérticorosetófilo se concentra la mayoría de lasespecies (42%), le siguen el matorral desérticomicrófilo (33%), el zacatal (20%) y el matorralcrasicaule (5%). De las 29 especies estudiadas,25 se encuentran en el corredor formado por lavertiente oriental de la Sierra de Librillos y lavertiente occidental de la Sierra La Trinidad,que comprende parte de los municipios deMatehuala, Villa de Guadalupe, Guadalcázar,Cerritos y Villa Hidalgo, área en donde se encuentran diversas especies endémicas y por lotanto vulnerables a la extinción
Searching for glycosylated natural products in actinomycetes and identification of novel macrolactams and angucyclines
Many bioactive natural products are glycosylated compounds in which the sugar components usually participate in interaction and molecular recognition of the cellular target. Therefore, the presence of sugar moieties is important, in some cases essential, for bioactivity. Searching for novel glycosylated bioactive compounds is an important aim in the field of the research for natural products from actinomycetes. A great majority of these sugar moieties belong to the 6-deoxyhexoses and share two common biosynthetic steps catalyzed by a NDP-D-glucose synthase (GS) and a NDP-D-glucose 4,6-dehydratase (DH). Based on this fact, seventy one Streptomyces strains isolated from the integument of ants of the Tribe Attini were screened for the presence of biosynthetic gene clusters (BGCs) for glycosylated compounds. Total DNAs were analyzed by PCR amplification using oligo primers for GSs and DHs and also for a NDP-D-glucose-2,3-dehydratases. Amplicons were used in gene disruption experiments to generate non-producing mutants in the corresponding clusters. Eleven mutants were obtained and comparative dereplication analyses between the wild type strains and the corresponding mutants allowed in some cases the identification of the compound coded by the corresponding cluster (lobophorins, vicenistatin, chromomycins and benzanthrins) and that of two novel macrolactams (sipanmycin A and B). Several strains did not show UPLC differential peaks between the wild type strain and mutant profiles. However, after genome sequencing of these strains, the activation of the expression of two clusters was achieved by using nutritional and genetic approaches leading to the identification of compounds of the cervimycins family and two novel members of the warkmycins family. Our work defines a useful strategy for the identification new glycosylated compounds by a combination of genome mining, gene inactivation experiments and the activation of silent biosynthetic clusters in Streptomyces strains
Antimicrobial Edible Films and Coatings for Meat and Meat Products Preservation
Animal origin foods are widely distributed and consumed around the world due to their high nutrients availability but may also provide a suitable environment for growth of pathogenic and spoilage microorganisms. Nowadays consumers demand high quality food with an extended shelf life without chemical additives. Edible films and coatings (EFC) added with natural antimicrobials are a promising preservation technology for raw and processed meats because they provide good barrier against spoilage and pathogenic microorganisms. This review gathers updated research reported over the last ten years related to antimicrobial EFC applied to meat and meat products. In addition, the films gas barrier properties contribute to extended shelf life because physicochemical changes, such as color, texture, and moisture, may be significantly minimized. The effectiveness showed by different types of antimicrobial EFC depends on meat source, polymer used, film barrier properties, target microorganism, antimicrobial substance properties, and storage conditions. The perspective of this technology includes tailoring of coating procedures to meet industry requirements and shelf life increase of meat and meat products to ensure quality and safety without changes in sensory characteristics
Soluble inflammatory mediators of synoviocytes stimulated by monosodium urate crystals induce the production of oxidative stress, pain, and inflammation mediators in chondrocytes
Brief report[Abstract] We hypothesized that the secretion of inflammatory mediators from synoviocytes affects the chondrocyte homeostasis of articular cartilage. This study was a preliminary attempt to elucidate the molecular mechanisms by which soluble mediators obtained from activated synoviocytes induce oxidative stress and inflammation in chondrocytes. We measured the concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor (NGF), superoxide anion (O2•-), hydrogen peroxide (H2O2), and nitric oxide (NO•) from articular human cells. First, we created a conditional basal medium by exposing synoviocytes (HS) to monosodium urate crystals (CBM). The chondrocytes were exposed to either CBM (CCM), urate crystals directly (CMSU), or remained untreated (CC) as a negative control. Data were analyzed by ANOVA tests; Bonferroni test was performed for multiple comparisons between groups. Interestingly, we observed that mediators of inflammation and oxidative stress were significantly higher in CCM than CMSU and CC groups (P<0.01). The specific concentrations were as follows: 19.85 ng/mL of IL-6, 9.79 ng/mL of IL-8, 5.17 ng/mL of NGF, and 11.91 ng/mL of MCP-1. Of note, we observed the same trend for reactive oxygen and nitrogen species (P<0.001). Soluble mediators secreted by synoviocytes after being activated with MSU crystals (as observed in individuals who present gout attacks) trigger chondrocyte activation intensifying the articular inflammatory, oxidative, and pain states that damage cartilage in OA; this damage is more severe even when compared to HC directly exposed to monosodium urate crystals. Key Points • The molecular relation between MSU depositions and cartilage damage could be mediated by pro-inflammatory soluble mediators and oxidative molecules. • The secretion of pro-inflammatory mediators by activated synoviocytes is more harmful to chondrocytes than a direct activation in the chondrocyte culture. • Under this model, there is an important imbalance in the matrix homeostasis due to changes in several chemokines, cytokines, and other factors such as NGF, as well as oxidative mediators
Most eastern boundary upwelling regions represent thermal refugia in the age of climate change
Eastern Boundary Upwelling Systems (EBUS) are regions where wind-driven coastal upwelling brings deep cold, nutrient-rich water to the surface and may be characterized by a coastal ‘footprint’ of sea surface temperature (SST) cooler than their surroundings. Previous studies have shown that EBUS coastal temperatures are responding differently to global ocean warming, warming slowly or not at all. However, the spatial dynamics of coastal upwelling footprints have yet to be investigated. In this paper, we use 20 years of high-resolution SST data derived from satellites (MUR SST) to test the null hypothesis that the extent of coastal upwelling footprints have remained stable over the period 2002–2022, consistent with the idea that these regions are thermal refugia. We investigate linear trends at different time scales, finding that the Humboldt and Iberian/Canary EBUS show no contraction of this footprint on annual or seasonal scales. The Benguela EBUS shows no change in its central and poleward subregions, but it exhibits contraction of the footprint in the equatorward subregion in the austral winter and spring. The California EBUS behaves differently: on the annual scale only the equatorward subregion shows contraction of the SST footprint, while on the seasonal scale, the entire EBUS show contraction during the fall or summer/fall. Summarizing the last two decades, most coastal habitats of EBUS (>80% of the areas tested) are remaining cool and may be acting as regional refugia from global warming, but this is true for some regions only during certain seasons. However, the declines in areal extent of upwelling in subregions of the California and Benguela EBUS indicate potential consequences for marine life and may help to explain changes in abundance, productivity, and redistributions of populations in these regions
Caracterización de huertos urbanos y periurbanos de Xalapa de Enríquez, Veracruz
La necesidad de adquirir alimentos de forma adecuada y sana ha llevado a buscar y fortalecer alternativas para su producción; en las ciudades se practica la agricultura urbana y periurbana (AUyP) y Xalapa, Veracruz, México, es un ejemplo de ello. Desde el año 2013 se autogestiono la Red de Agricultura Urbana y Periurbana de Xalapa (RAUPX), en la cual se centró el objetivo de la presente investigación, que consistió en caracterizar los huertos de la RAUPX, en función de las variables: tamaño de huerto, diversidad (índice de Shannon), presencia de artropofauna y prácticas de manejo fitosanitarias; con el fin de diagnosticar y aportar propuestas para mejorar el manejo integrado de plagas. Los resultados incluyen datos generales productor-huerto tales como rango de edad, nivel de estudios, superficie, familias botánicas representativas, presencia de artropofauna en relación con las especies cultivadas y manejo de prácticas fitosanitarias de acuerdo con su complejidad. Las prácticas fitosanitarias que realizan los productores son de forma correctiva en vez de preventiva y están moderadamente relacionadas con la presencia de plagas
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