159 research outputs found

    Maintenance of cell type-specific connectivity and circuit function requires Tao kinase

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    Sensory circuits are typically established during early development, yet how circuit specificity and function are maintained during organismal growth has not been elucidated. To gain insight we quantitatively investigated synaptic growth and connectivity in the Drosophila nociceptive network during larval development. We show that connectivity between primary nociceptors and their downstream neurons scales with animal size. We further identified the conserved Ste20-like kinase Tao as a negative regulator of synaptic growth required for maintenance of circuit specificity and connectivity. Loss of Tao kinase resulted in exuberant postsynaptic specializations and aberrant connectivity during larval growth. Using functional imaging and behavioral analysis we show that loss of Tao-induced ectopic synapses with inappropriate partner neurons are functional and alter behavioral responses in a connection-specific manner. Our data show that fine-tuning of synaptic growth by Tao kinase is required for maintaining specificity and behavioral output of the neuronal network during animal growth

    Accounting for the instantaneous disorder in the enzyme-substrate Michaelis complex to calculate the Gibbs free energy barrier of an enzyme reaction

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    Many enzyme reactions present instantaneous disorder. These dynamic fluctuations in the enzyme-substrate Michaelis complexes generate a wide range of energy barriers that cannot be experimentally observed, but that determine the measured kinetics of the reaction. These individual energy barriers can be calculated using QM/MM methods, but then the problem is how to deal with this dispersion of energy barriers to provide kinetic information. So far, the most usual procedure has implied the so-called exponential average of the energy barriers. In this paper, we discuss the foundations of this method, and we use the free energy perturbation theory to derive an alternative equation to get the Gibbs free energy barrier of the enzyme reaction. In addition, we propose a practical way to implement it. We have chosen four enzyme reactions as examples. In particular, we have studied the hydrolysis of a glycosidic bond catalyzed by the enzymeThermus thermophilusβ-glycosidase, and the mutant Y284P Ttb-gly, and the hydrogen abstraction reactions from C 13and C 7of arachidonic acid catalyzed by the enzyme rabbit 15-lipoxygenase-1

    GPR application on geothermal studies: the case study of the thermal baths of San Xusto (Pontevedra, Spain)

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    Geophysical studies are frequently used on the geothermal field to define and characterize deep structures. However, shallow investigations are also needed for understanding the origin and local potential structures of a promising geothermal site. In this research, it is intended to present a review of the possibilities of the application of ground-penetrating radar (GPR) on the study of geothermal resources and how this geophysical technique can contribute to improving the energy use of these thermal resources. For this, the specific case of application to the investigation of the thermal baths of San Xusto (Pontevedra, Spain) is included in this work, whose interest for the region makes it necessary to perform an in-depth analysis of the original thermal structure. A GPR survey with frequency antennas of 200 and 500 MHz was conducted. Additionally, chemical analyses were performed to characterize the thermal water in the San Xusto site. As a result, a hot spring was detected by identifying reverberation phenomena in GPR imaging due to the presence of metal compounds and silica. Locating the origin of the thermal springs could allow for a more efficient use of the thermal resources as well as the hydrothermal possibilities of the area.Xunta de Galicia | Ref. ED431F 2021/08Ministerio de Ciencia e Innovación | Ref. RYC2019-026604-

    The application of the silicon-based biostimulant Codasil® offset water deficit of lettuce plants

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    This work was supported by the PAI program (Plan Andaluz de Investigación, Grupo de Investigación AGR282).Water stress is one of the most important factors limiting plant growth and development. The use of biostimulants is becoming increasingly important to mitigate the effects of several stresses such as water deficit. The objective of this study is to assess the effects of the biostimulant Codasil® composed mainly of oligo/polypeptides, amino acids (AAs), Si, and K on lettuce growth, physiology, and water stress tolerance. For this aim, lettuce plants were grown under water deficit (75% of field capacity) and with the application of Codasil®. Parameters related to growth, oxidative stress, photosynthesis, pigment concentration, and proline metabolism were analyzed. The results showed that the biostimulant considerably enhanced plant growth under water stress conditions. Likewise, Codasil® reduced lipid peroxidation and H2O2 levels and protected photosynthesis performance. Besides, plants supplied with the biostimulant accumulated more Si and presented a lower Pro accumulation and a lower Pro metabolism induction. Altogether, this study confirms the usefulness of Codasil® as a biostimulant to mitigate the effects of water deficitPlan Andaluz de Investigación AGR28

    Impact of the historical introduction of exotic fishes on the chironomid community of Lake Azul (Azores Islands)

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    Little is known about the effect of top predator introduction in historically fishless communities, especially on remote islands. This issue is important because it might strongly affect climate reconstructions derived from biota assemblages such as chironomids. Head capsule larval remains of chironomids have been studied in a 660 years lacustrine sedimentary sequence from Lake Azul (Sao Miguel Island, Azores archipelago) to assess the extent and timescale of the effect of the predator introduction occurring in this historically fishless lake. Analysis of similarity showed that the chironomid assemblage was statistically different before and after predator introduction (R = 0.78; p < 0.001). Abundance of chironomids was about 40% greater in the fishless lake period compared to the period in the presence of predator. Results show major change in chironomid assemblage coinciding with the first time of goldfish introduction (around 1790 CE), followed by carp (1890 CE) and pike (1979 CE) introductions. The composition of feeding group guilds changed following a pattern characterized by a decrease in abundance of detritivorous and predaceous taxa and an increase in abundance of grazing chironomid taxa. This study suggests that predator introduction was the most important factor affecting the chironomid assemblages in this natural, Azorean fishless lake, but predators did not affect all chironomid species. Other external forcings like major climate oscillations, anthropogenic activities in the catchment basin, and volcanic eruptions seem to play an additional role. The latest stage of the warm and arid Medieval Climate Anomaly (1000–1300 CE) favoured the occurrence of some warm-adapted chironomid taxa, which were absent through the Little Ice Age (ca. 1450–1850 CE) cool period.Azores. Fundo Regional da Ciência e Tecnologia; M3.1.7/F/009/2011Ministerio de Ciencia e Innovación; CGL2010-15767Ministerio de Ciencia e Innovación; CGL2013-40608-RPortugal. Fundação para a Ciência e Tecnologia; SFRH/BPD/99461/2014Portugal. Fundação para a Ciência e Tecnologia; SFRH/BPD/79923/2011Portugal. Fundação para a Ciência e Tecnologia; UID/BIA/50027/2013Portugal. Fundação para a Ciência e Tecnologia; POCI-01-0145-FEDER-00682

    Extremely low viral reservoir in treated chronically HIV-1-infected individuals

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    Altres ajuts: This research was sponsored in part by Grifols and by Merck Sharp & Dohme España, S.A. (IISP 54925). The funding organizations had no input in the design of the study; in the collection, analyses, or interpretation of the data; writing of the manuscript; or in the decision to submit the study for publication. NH received a post-doctoral grant from the Jaqueline Beytout Foundation. FG received the support of "José María Segovia de Arana" contracts (2019) and MMT from the NIH (R01AI143457).Small viral reservoirs are found predominantly in HIV-1 controllers and individuals treated during acute/early HIV-1 infection. However, other HIV + individuals could naturally also harbour low viral reservoirs. We screened 451 HIV-1-infected treated-individuals with suppressed plasma viremia for at least 3 years and stored cryopreserved peripheral blood mononuclear cells (PBMCs). Total HIV-DNA was analysed in PBMCs with ddPCR. Individuals with 50 HIV-DNA copies/10 6 PBMCs) to analyse total HIV-DNA, T-cell and NK-cell populations, HIV-1 specific antibodies, and plasma inflammation markers. We found that 9.3% of the individuals screened had <50 HIV-DNA copies/10 6 PBMCs. At least 66% initiated cART during the chronic phase of HIV-1 infection (cp-LoViReT). Cp-LoViReT harboured lower levels of HIV-DNA before cART and after treatment introduction the decays were greater compared to controls. They displayed a marked decline in quantity and avidity in HIV-specific antibodies after initiation of cART. Cp-LoViReT had fewer CD8 + T and T in the absence of cART, and higher CD8 + T after 18 months on therapy. Treated chronically HIV-1-infected LoViReT represent a new phenotype of individuals characterized by an intrinsically reduced viral reservoir, less impaired CD8 + T-cell compartment before cART, and low circulating HIV-1 antigens despite being treated in the chronic phase of infection. The identification of this unique group of individuals is of great interest for the design of future eradication studies. MSD Spai

    Effectiveness, cost-utility, and benefits of a multicomponent therapy to improve the quality of life of patients with fibromyalgia in primary care : a mixed methods study protocol

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    Introduction:Fibromyalgia (FM) is a chronic condition characterized by chronic pain, fatigue and loss of function which significantly impairs quality of life. Although treatment of FM remains disputed, some studies point at the efficacy of interdisciplinary therapy. This study aims to analyze the effectiveness, cost-utility and benefits of a multicomponent therapy on quality of life (main variable), functional impact, mood and pain in people suffering from FM that attend primary care centers (PCCs) of the Catalan Institute of Health (ICS).Methods and analysis:A 2-phase, mixed methods study has been designed following Medical Research Council guidance. Phase 1: Pragmatic randomized clinical trial with patients diagnosed with FM that attend one of the 11 PCCs of the ICS Gerència Territorial Terres de l'Ebre. We estimate a total sample of 336 patients. The control group will receive usual clinical care, while the multicomponent therapy group (MT group) will receive usual clinical care plus group therapy (consisting of health education, exercise and cognitive-behavioural therapy) during 12 weeks in 2-hourly weekly sessions. Analysis: the standardized mean response and the standardized effect size will be assessed at 3, 9, and 15 months after the beginning of the study using multiple linear regression models. Utility measurements will be used for the economic analysis. Phase 2: Qualitative socio constructivist study to evaluate the intervention according to the results obtained and the opinions and experiences of participants (patients and professionals). We will use theoretical sampling, with 2 discussion groups of participants in the multicomponent therapy and 2 discussion groups of professionals of different PCCs. A thematic content analysis will be carried out.Ethics and dissemination:This study protocol has been approved by the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P18/068). Articles will be published in international, peer-reviewed scientific journals.Trial registration:Clinical-Trials.gov: NCT04049006

    Adsorción de impurezas del jugo clarificado de la industria azucarera mediante biomasa pirolizada.

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    En este trabajo se prepararon dos adsorbentes a partir de la cáscara del fruto de Jatropha curcas, para evaluar su efectividad en la remoción de impurezas coloreadas presentes en el jugo clarificado obtenido del proceso de fabricación de azúcar de caña. Partiendo de la cáscara molida y tamizada (diámetro<2 mm) del fruto de Jatropha curcas se fabricaron dos pirolizados mediante deshidratación inicial con ácido concentrados (ácido sulfúricoy ácido fosfórico), y posterior pirólisis a 500 ºC. Se verificó, mediante análisis estadístico, que el PAF (elaborado por deshidratación con ácido fosfórico) eliminó el 47,4±1,8 % de las impurezas coloreadas, con respecto al 36,8±1,6 % eliminado por el PAS (elaborado por deshidratación con ácido sulfúrico). Los parámetros de calidad del PAF se encuentran dentro de los intervalos establecidos para este tipo de material adsorbente. Ninguno de los pirolizados contaminó el jugo clarificado. Teniendo en cuenta los resultados, se sugiere la introducción de estos materiales en el proceso productivo de la industria azucarera. Palabras clave: Jatropha curcas, pirolizado, remoción de color, jugo clarificado

    Novel interactions between phytoplankton and bacteria shape microbial seasonal dynamics in coastal ocean waters

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    Trophic interactions between marine phytoplankton and heterotrophic bacteria are at the base of the biogeochemical carbon cycling in the ocean. However, the specific interactions taking place between phytoplankton and bacterial taxa remain largely unexplored, particularly out of phytoplankton blooming events. Here, we applied network analysis to a 3.5-year time-series dataset to assess the specific associations between different phytoplankton and bacterial taxa along the seasonal scale, distinguishing between free-living and particle-attached bacteria. Using a newly developed network post-analysis technique we removed bacteria-phytoplankton correlations that were primarily driven by environmental parameters, to detect potential biotic interactions. Our results indicate that phytoplankton dynamics may be a strong driver of the inter-annual variability in bacterial community composition. We found the highest abundance of specific bacteria-phytoplankton associations in the particle-attached fraction, indicating a tighter bacteria-phytoplankton association than in the free-living fraction. In the particle-associated fraction we unveiled novel potential associations such as the one between Planctomycetes taxa and the diatom Leptocylindrus spp. Consistent correlations were also found between free-living bacterial taxa and different diatoms, including novel associations such as those between SAR11 with Naviculales diatom order, and between Actinobacteria and Cylindrotheca spp. We also confirmed previously known associations between Rhodobacteraceae and Thalassiosira spp. Our results expand our view on bacteria-phytoplankton associations, suggesting that taxa-specific interactions may largely impact the seasonal dynamics of heterotrophic bacterial communities
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