69 research outputs found

    Evidence for mid-Holocene rice domestication in the Americas

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    This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this recordThe development of agriculture is one of humankind's most pivotal achievements. Questions about plant domestication and the origins of agriculture have engaged scholars for well over a century, with implications for understanding its legacy on global subsistence strategies, plant distribution, population health and the global methane budget. Rice is one of the most important crops to be domesticated globally, with both Asia (Oryza sativa L.) and Africa (Oryza glaberrima Steud.) discussed as primary centres of domestication. However, until now the pre-Columbian domestication of rice in the Americas has not been documented. Here we document the domestication of Oryza sp. wild rice by the mid-Holocene residents of the Monte Castelo shell mound starting at approximately 4,000 cal. yr BP, evidenced by increasingly larger rice husk phytoliths. Our data provide evidence for the domestication of wild rice in a region of the Amazon that was also probably the cradle of domestication of other major crops such as cassava (Manihot esculenta), peanut (Arachis hypogaea) and chilli pepper (Capsicum sp.). These results underline the role of wetlands as prime habitats for plant domestication worldwide.The research was funded by the European Research Council project ‘Pre-Columbian Amazon-Scale Transformations’ (ERC-CoG 616179) to J.I. L.M.H. was funded by CAPES (Ministry of Education, Brazil) and Monte Castelo fieldwork was funded by grants from the Brazilian National Science Development Council (CNPq-307179/2013-3) and The National Geographic Society (W243-12) to E.G.N

    MOF nanoparticles coated by lipid bilayers and their uptake by cancer cells

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    Supramolecular templating techniques have been widely used to direct the formation of porous materials with the goal of introducing permanent mesoporosity. While surfactant-directed self-assembly has been exploited for inorganic materials such as titania, silica, organosilica, and zeolites, it has rarely been applied to metal-organic frameworks (MOFs) and coordination polymers. Here we introduce a new family of gemini surfactant-directed zinc imidazolates, referred to as mesostructured imidazolate frameworks (MIFs), and present a detailed study on the influence of different gemini-type surfactants on the formation mechanism and structures of the resulting zinc imidazolates. The proposed formation mechanism for MIF-type materials involves co-assembly and crystallization processes that yield lamellar mesostructured imidazolate frameworks. Understanding and controlling such processes also has implications for the syntheses of microporous zinc imidazolate framework (ZIF) materials, whose formation can be suppressed in surfactant-rich solutions, whereas formation of MIF materials is favored in the presence of surfactants and triggered by the addition of halogenides. Solid-state 2D 13C1H HETCOR NMR measurements on prototypic CTAB-directed MIF-1 establish that the head group moieties of the surfactant molecules interact strongly with the zinc-imidazolate-bromide sheets. Additionally, the NMR analyses suggest that MIF-1 has a significant fraction of surfactant molecules that are interdigitated between the zinc-imidazolate-bromide sheets with an antiparallel stacking arrangement, consistent with the high thermal and chemical stability of the MIF hybrid materials

    Metal–Organic Framework Nanoparticles Induce Pyroptosis in Cells Controlled by the Extracellular pH

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    Ion homeostasis is essential for cellular survival, and elevated concentrations of specific ions are used to start distinct forms of programmed cell death. However, investigating the influence of certain ions on cells in a controlled way has been hampered due to the tight regulation of ion import by cells. Here, it is shown that lipid‐coated iron‐based metal–organic framework nanoparticles are able to deliver and release high amounts of iron ions into cells. While high concentrations of iron often trigger ferroptosis, here, the released iron induces pyroptosis, a form of cell death involving the immune system. The iron release occurs only in slightly acidic extracellular environments restricting cell death to cells in acidic microenvironments and allowing for external control. The release mechanism is based on endocytosis facilitated by the lipid‐coating followed by degradation of the nanoparticle in the lysosome via cysteine‐mediated reduction, which is enhanced in slightly acidic extracellular environment. Thus, a new functionality of hybrid nanoparticles is demonstrated, which uses their nanoarchitecture to facilitate controlled ion delivery into cells. Based on the selectivity for acidic microenvironments, the described nanoparticles may also be used for immunotherapy: the nanoparticles may directly affect the primary tumor and the induced pyroptosis activates the immune system

    A correlation analysis of Light Microscopy and X-ray MicroCT imaging methods applied to archaeological plant remains’ morphological attributes visualization

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    In this work, several attributes of the internal morphology of drupaceous fruits found in the archaeological site Monte Castelo (Rondonia, Brazil) are analyzed by means of two different imaging methods. The aim is to explore similarities and differences in the visualization and analytical properties of the images obtained via High Resolution Light Microscopy and X-ray micro-computed tomography (X-ray MicroCT) methods. Both provide data about the three-layered pericarp (exo-, meso- and endocarp) of the studied exemplars, defined by cell differentiation, vascularisation, cellular contents, presence of sclerenchyma cells and secretory cavities. However, it is possible to identify a series of differences between the information that can be obtained through each of the methods. These variations are related to the definition of contours and fine details of some characteristics, their spatial distribution, size attributes, optical properties and material preservation. The results obtained from both imaging methods are complementary, contributing to a more exhaustive morphological study of the plant remains. X-ray MicroCT in phase-contrast mode represents a suitable non-destructive analytic technique when sample preservation is required

    Multifunctional Nanoparticles by Coordinative Self-Assembly of His-Tagged Units with Metal–Organic Frameworks

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    Self-assembly of individual units into multicomponent complexes is a powerful approach for the generation of functional superstructures. We present the coordinative interaction of oligohistidine-tags (His-tags) with metal-organic framework nanoparticles (MOF NPs). By this novel concept, different molecular units can be anchored on the outer surface of MOF NPs in a self-assembly process generating multifunctional nanosystems. The article focuses on two main objectives: first, the detailed investigation of the assembly process and fundamental establishment of the novel functionalization concept; and second, its subsequent use for the development of biomacromolecule (e.g., peptides and proteins) delivery vehicles. Three exemplary MOF structures, MIL-88A, HKUST-1, and Zr-fum, based on different metal components, were selected for the external binding of various His-tagged synthetic peptides and recombinant or chemically H6-modified proteins. Evidence for simultaneous assembly of different functional units with Zr-fum MOF NPs as well as their successful transport into living cells illustrate the promising potential of the self-assembly approach for the generation of multifunctional NPs and future biological applications. Taking the high number of possible MOF NPs and different functional units into account, the reported functionalization approach opens great flexibility for the targeted synthesis of multifunctional NPs for specific purposes

    Glanders Diagnosis in an Asymptomatic Mare from Brazil: Insights from Serology, Microbiological Culture, Mass Spectrometry, and Genome Sequencing.

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    ABSTRACT - This manuscript elucidates the occurrence of glanders in an asymptomatic mare from Brazil presenting positive Burkholderia mallei antibody titers. The diagnosis was established through a multi-pronged approach encompassing microbiological culture, mass spectrometry, and genome sequencing. The outbreak occurred in 2019 in Tatuí, São Paulo, Brazil, and the infected mare, despite displaying no clinical symptoms, had multiple miliary lesions in the liver, as well as intense catarrhal discharge in the trachea. Samples were collected from various organs and subjected to bacterial isolation, molecular detection, and identification. The strain was identified as B. mallei using PCR and confirmed by MALDI-TOF mass spectrometry. Whole-genome sequencing revealed a genome size of 5.51 Mb with a GC content of 65.8%, 5871 genes (including 4 rRNA and 53 tRNA genes), and 5583 coding DNA sequences (CDSs). Additionally, 227 predicted pseudogenes were detected. In silico analysis of different genomic loci that allow for differentiation with Burkholderia pseudomallei confirmed the identity of the isolate as B. mallei, in addition to the characteristic genome size. The BAC 86/19 strain was identified as lineage 3, sublineage 2, which includes other strains from Brazil, India, and Iran. The genome sequencing of this strain provides valuable information that can be used to better understand the pathogen and its epidemiology, as well as to develop diagnostic tools for glanders

    Professional profile and practice of psychiatrists in brazil

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    Com o objetivo de identificar o perfil profissional de psiquiatras do Brasil, foram escolhidos para estudo cinco Estados representativos de cada região do País (Bahia, Pará, Rio de Janeiro, São Paulo, Rio Grande do Sul, além do Distrito Federal). A amostra consistiu de 430 membros da ABP, que responderam a questionário enviado pelo correio. Os dados foram analisados pelo sistema EPIINFO. Veri ficou-se que 76,5% dos psiqui atras estudados fazem ou fizeram supervisão de seu trabalho, 65, I % participam de grupos de estudo, 51,9% submeteram-se a psicoterapia pessoal, 71,2% foram ou são pacientes de psicanálise. Quanto à atividade profissional, 30,2% do tempo são dedicados a instituições públicas, 11 ,6% a instituições privadas e 48,3% ao consultório particular. Neste, predominam as técnicas psicotenápicas

    Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

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    Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/ structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the noncoated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier
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