43 research outputs found
EFICIÊNCIA RELATIVA DE FOSFATOS NATURAIS NA ADUBAÇÃO DE PLANTIO DE MUDAS DE Eucalyptus dunnii MAIDEN E Eucalyptus benthamii MAIDEN ETCAMBAGEM EM SOLO SEM E COM CALAGEM
http://dx.doi.org/10.5902/1980509817443The eucalyptus has a pronounced demand for phosphorus (P) in the initial growth. Therefore, its P critical level is higher in the early stages of development, decreasing with plant age. The study was carried out to evaluate the response to fertilization and relative efficiency (RE) of phosphates (RPs) in the initial growth of eucalyptus. For this, two experiments were conducted in a greenhouse, from October 2010 to February 2011, at the University of Santa Catarina (UDESC), in Lages, Santa Catarina state, one with Eucalyptus dunnii and another with Eucalyptus benthamii using the following phosphorus sources: Bayovar, Gafsa, Djebel and triple superphosphate, plus a control without P. These P treatments were applied in soils with and without liming. The experimental design was completely randomized in a 5 x 2 factorial arrangement and with four replications. Plants were grown for 110 days and after harvest, were determined dry matter (by difference of wet weight and dry weight) and P accumulation in plant tissue from different parts of the plant (determined by spectrophotometry at a wavelength of 882 nm after reduction of phospho-molibidate complex with ascorbic acid). The relative efficiency of RPs (%) was calculated from data obtained from dry matter of shoots and total dry matter. For the correlation between the parameters of P content in the plants and soil available P it was applied Pearson’s correlation (P <0.05). All sources of P were similar to each other, but were higher than the control one, however, the use of these sources resulted in an increase in dry matter production and P content accumulated in the shoots of Eucalyptus benthamii and Eucalyptus dunnii compared to the control treatment regardless the soil amendment. In soil without lime, the RE averages were 75, 91 and 94%, respectively for RPs Bayovar, Gafsa and Djebel. For soils with lime, the RE averages were 65, 24 and 25% for the same phosphate sources. In treatments without liming the relative efficiency of RPs was higher compared to soils with lime.http://dx.doi.org/10.5902/1980509817443O eucalipto possui uma grande exigência de fósforo (P) na fase de implantação do povoamento. Por isso o seu nível crítico de P é mais alto na fase inicial de desenvolvimento, diminuindo com o aumento da idade. O trabalho objetivou avaliar a resposta no crescimento inicial de eucalipto à adubação fosfatada e a eficiência relativa (ER) de fosfatos naturais (FNs) em solos sem e com calagem. Para isso, foram conduzidos, no período de outubro de 2010 a fevereiro de 2011, dois experimentos em casa de vegetação, na Universidade do Estado de Santa Catarina (UDESC), em Lages (SC), um com mudas de Eucalyptus dunnii e outro com Eucalyptus benthamii, utilizando os FNs Bayovar, Gafsa e Djebel, além do superfosfato triplo e testemunha (sem P), em um Cambissolo Húmico sem e com calagem. O delineamento experimental utilizado foi o inteiramente casualizado em arranjo fatorial 5 x 2 (cinco fontes de P e dois níveis de calagem), com quatro repetições. As plantas foram cultivadas por 110 dias e após a colheita, foram determinados a produção de matéria seca (por diferença de peso úmido e peso seco) e o acúmulo de P no tecido vegetal das diferentes partes da planta (determinado por espectrofotometria em comprimento de onda de 882 nm, após redução do complexo fosfomolibidato com ácido ascórbico). A eficiência relativa dos FNs (%) foi calculada a partir dos dados obtidos de matéria seca de parte aérea e matéria seca total. Para a correlação entre os parâmetros de teor de P acumulado na planta e os teores de P disponível no solo foi aplicado o Teste de Correlação de Pearson (P<0,05). Todas as fontes de P apresentaram comportamento semelhante entre si, mas foram superiores à testemunha, entretanto, o uso destas fontes provocou aumento na produção de matéria seca e no teor de P acumulado na parte aérea das plantas de Eucalyptus benthamii e Eucalyptus dunnii aos 110 dias de crescimento em relação ao tratamento testemunha independente da correção do solo. No solo sem calagem, as ERs médias foram 75, 91 e 94% respectivamente para os FNs Bayovar, Gafsa e Djebel. Para os solos com calagem, as ERs médias foram 65, 24 e 25%, para os mesmos fosfatos. Nos tratamentos sem adição de calcário, a eficiência relativa dos FNs foi maior em comparação aos solos com calagem
Adenosine A2A receptor as a potential regulator of Mycobacterium leprae survival mechanisms: new insights into leprosy neural damage
BackgroundLeprosy is a chronic infectious disease caused by Mycobacterium leprae, which can lead to a disabling neurodegenerative condition. M. leprae preferentially infects skin macrophages and Schwann cells–glial cells of the peripheral nervous system. The infection modifies the host cell lipid metabolism, subverting it in favor of the formation of cholesterol-rich lipid droplets (LD) that are essential for bacterial survival. Although researchers have made progress in understanding leprosy pathogenesis, many aspects of the molecular and cellular mechanisms of host–pathogen interaction still require clarification. The purinergic system utilizes extracellular ATP and adenosine as critical signaling molecules and plays several roles in pathophysiological processes. Furthermore, nucleoside surface receptors such as the adenosine receptor A2AR involved in neuroimmune response, lipid metabolism, and neuron–glia interaction are targets for the treatment of different diseases. Despite the importance of this system, nothing has been described about its role in leprosy, particularly adenosinergic signaling (AdoS) during M. leprae–Schwann cell interaction.MethodsM. leprae was purified from the hind footpad of athymic nu/nu mice. ST88-14 human cells were infected with M. leprae in the presence or absence of specific agonists or antagonists of AdoS. Enzymatic activity assays, fluorescence microscopy, Western blotting, and RT-qPCR analysis were performed. M. leprae viability was investigated by RT-qPCR, and cytokines were evaluated by enzyme-linked immunosorbent assay.ResultsWe demonstrated that M. leprae-infected Schwann cells upregulated CD73 and ADA and downregulated A2AR expression and the phosphorylation of the transcription factor CREB (p-CREB). On the other hand, activation of A2AR with its selective agonist, CGS21680, resulted in: 1) reduced lipid droplets accumulation and pro-lipogenic gene expression; 2) reduced production of IL-6 and IL-8; 3) reduced intracellular M. leprae viability; 4) increased levels of p-CREB.ConclusionThese findings suggest the involvement of the AdoS in leprosy neuropathogenesis and support the idea that M. leprae, by downmodulating the expression and activity of A2AR in Schwann cells, decreases A2AR downstream signaling, contributing to the maintenance of LD accumulation and intracellular viability of the bacillus
Convalescent plasma for COVID-19 in hospitalised patients : an open-label, randomised clinical trial
Background: The effects of convalescent plasma (CP) therapy in hospitalised patients with coronavirus disease 2019 (COVID-19) remain uncertain. This study investigates the effect of CP on clinical improvement in these patients. Methods: This is an investigator-initiated, randomised, parallel arm, open-label, superiority clinical trial. Patients were randomly (1:1) assigned to two infusions of CP plus standard of care (SOC) or SOC alone. The primary outcome was the proportion of patients with clinical improvement 28 days after enrolment. Results: A total of 160 (80 in each arm) patients (66.3% critically ill, 33.7% severely ill) completed the trial. The median (interquartile range (IQR)) age was 60.5 (48–68) years; 58.1% were male and the median (IQR) time from symptom onset to randomisation was 10 (8–12) days. Neutralising antibody titres >1:80 were present in 133 (83.1%) patients at baseline. The proportion of patients with clinical improvement on day 28 was 61.3% in the CP+SOC group and 65.0% in the SOC group (difference −3.7%, 95% CI −18.8–11.3%). The results were similar in the severe and critically ill subgroups. There was no significant difference between CP+SOC and SOC groups in pre-specified secondary outcomes, including 28-day mortality, days alive and free of respiratory support and duration of invasive ventilatory support. Inflammatory and other laboratory marker values on days 3, 7 and 14 were similar between groups. Conclusions: CP+SOC did not result in a higher proportion of clinical improvement on day 28 in hospitalised patients with COVID-19 compared to SOC alone
Molluscicidal effect of Euphorbia umbellata (Pax) Bruyns latex on Biomphalaria glabrata, Schistosoma mansoni host snail
ABSTRACT Euphorbia umbellata (Pax) Bruyns is an easily cultivated shrub, with occurrence in the tropical regions of the American and African continents. Chemical studies have revealed that the latex of this plant is rich in terpene compounds, which are highly toxic to snails Biomphalaria glabrata (Basommatophora: Planorbidae). The aim of this study was to evaluate the chemical composition and molluscicidal activity of the latex produced by E. umbellata, as well as the safety of its application in aquatic environments. The concentration of latex that killed 90% of the exposed snails after 24 h exposure (LC90) was 3.69 mg/L. Toxicity bioassays using Danio rerio (zebrafish) revealed that these animals were less susceptible to latex than planorbids. However, it is important to perform other toxicity tests to ensure the feasibility of using latex to control populations of mollusks that contribute to schistosomiasis transmission. A phytochemical screening performed with the E. umbellata latex identified the triterpenoid and coumarin class. Further studies are warranted to isolate, identify, and test the active compounds of E. umbellata latex in B. glabrata
Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension
OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo
Minimal Symptom Expression' in Patients With Acetylcholine Receptor Antibody-Positive Refractory Generalized Myasthenia Gravis Treated With Eculizumab
The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil
The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others