Clay content drives carbon stocks in soils under a plantation of Eucalyptus saligna Labill. in southern Brazil

Soil carbon accumulation is largely dependent on net primary productivity. To our knowledge, there have been no studies investigating the dynamics of carbon accumulation in weathered subtropical soils, especially in managed eucalyptus plantations. We quantified the seasonal input of leaf litter, the leaf decomposition rate and soil carbon stocks in an commercial plantation of Eucalyptus saligna Labill. in southern Brazil. Our goal was to evaluate, through multiple linear regression, the influence that certain chemical characteristics of litter, as well as chemical and physical characteristics of soil, have on carbon accumulation in soil organic matter fractions. Variables related to the chemical composition of litter were not associated with the soil carbon stock in the particulate and mineral fractions. However, certain soil characteristics were significantly associated with the carbon stock in both fractions. The concentrations of nutrients associated with plant growth and productivity, such as phosphorus, sulfur, copper and zinc, were associated with variations in the labile carbon pool (particulate fraction). Clay content was strongly associated with the carbon stock in the mineral fraction. The carbon accumulation and stabilization in weathered subtropical Ultisol seems to be mainly associated with the intrinsic characteristics of the soil, particularly clay content, rather than with the quantity, chemical composition or decomposition rate of the litter

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

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 understanding 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,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 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 underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities 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 organism 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 neglected 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 lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, 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 organism 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 neglected 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 lost

Induction of immune response in broiler chickens immunized with recombinant FliC and challenged by Salmonella Typhimurium

Este estudo investigou a resposta imunitária de frangos de corte após a imunização oral com flagelina recombinante (rFliC) de Salmonella Typhimurium conjugada com micropartículas de alginato de sódio, e como intensificador de resposta imune foi associada a proteína subunidade B da toxina colérica (rCTB) e pool de Lactobacillus spp. (PL). As respostas imunes foram avaliadas por dosagem de IgY sérica e IgA do fluído intestinal e imunomarcação de linfócitos T CD8+ presentes no ceco. Os animais imunizados foram desafiados aos 21 dias após tratamento com Salmonella Typhimurium (ST). Foi observado em todos os grupos imunizados um aumento significativo (p<0,05) nos níveis de IgA (μg/mL) principalmente três semanas após as imunizações. Os níveis de IgY sérica (μg/mL) foram pouco influenciados pelos tratamentos, apenas na segunda semana após imunização observou-se diferenças significativas (p<0,05) entre os grupos. Observou-se que o número de linfócitos T CD8+ apresentou diferença significativa entre os tratamentos e o controle negativo após o desafio. Quanto a recuperação de Salmonella Typhimurium, observou-se que 48 horas após o desafio já não havia detecção do agente nos grupos T2 (rFliC+rCTb), T3 (rFliC+PL) e T4 (rFliC+rCTB+PL). Concluí-se que rFliC administrada, via oral, associada ou não a Lactobacillus spp e rCTB, demonstrou induzir significativamente a resposta imune humoral e que as aves imunizadas foram mais eficientes na eliminação de Salmonella após desafio.The study examined (1) the immune response in broiler chickens after oral immunization with recombinant flagellin (rFliC) from Salmonella Typhimurium conjugated with sodium alginate microparticles, and the immune response enhancement in association with recombinant cholera toxin B subunit protein (rCTB) and pool of Lactobacillus spp. (PL). The immune responses were evaluated by dosage of IgY serum and IgA from intestinal fluid and immunostaining of CD8+ T lymphocytes in the cecum. The immunized animals were challenged with Salmonella Typhimurium (ST) 21 days after treatment. In all immunized groups, a significant increase (p<0.05) was observed in IgA levels (μg/mL), especially three weeks after immunization. The serum IgY levels (μg/mL) were little affected by the treatments and differed significantly among groups only in the second post-immunization week (p<0.05). After the challenge, the number of CD8+ T cells differed significantly between the treatments and negative control. Retrieval of Salmonella Typhimurium was not detected at 48 hours after the challenge in T2 (rFliC+rCTb), T3 (rFliC+PL) and T4 (rFliC+rCTB PL). The rFliC administered orally with or without rCTB and Lactobacillus spp. produces significant induction of humoral immune response, and the immunized chickens were more effective in eliminating Salmonella after challenge.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Molecular docking and molecular dynamicsof semi-synthetic piperidine alkaloids as acetylcholinesterase inhibitors

A mistura dos derivados semissintéticos cloridrato da (–)-3-O-acetil-cassina e cloridrato da (–)-3-O-acetil-espectalina, preparada a partir da mistura dos alcalóides (–)-cassina e (–)-espectalina (4:1) obtida de Senna spectabilis, é um potente inibidor da acetilcolinesterase (AChE), assim justificando mais estudos moleculares. Neste sentido, estudos de docking e dinâmica moleculares foram conduzidos neste trabalho com o objetivo de adquirir uma compreensão mais profunda de todos os aspectos estruturais das moléculas cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina, as quais diferem em seus potenciais inibidores de AChE. Os dois derivados em estudo apresentaram diversas interações com o sítio periférico aniônico dentro da cavidade catalítica de AChE de Torpedo californica. Entretanto, somente o composto majoritário (–)-3-O-acetil-cassina mostrou interação com a tríade catalítica de maneira significativa. As simulações de dinâmica molecular utilizando água como solvente foram importantes para compreender as interações hipotéticas entre cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina com AChE. Os dados obtidos indicam que o composto (–)-3-O-acetil-cassina é o inibidor da enzima mais potente possivelmente devido às suas interações favoráveis com a proteína, com menor custo de dessolvatação. Estes resultados sugerem que o tamanho da cadeia lateral influencia no potencial inibitório das moléculas avaliadas e podem representar o ponto de partida para o desenvolvimento de novos derivados de (–)-3-O-acetil-cassina, objetivando a descoberta de inibidores de AChE mais eficazes.The mixture of semi-synthetic derivatives (–)-3-O-acetyl-cassine hydrochloride and (–)-3-O-acetyl-spectaline hydrochloride, prepared from the mixture of natural alkaloids (–)-cassine and (–)-spectaline (4:1) isolated from Senna spectabilis, has been shown to be a potent acetylcholinesterase (AChE) inhibitor, thereby prompting further molecular studies. In this sense, docking and dynamic molecular studies were carried out in this work, aiming to acquire a deeper understanding about all the structural aspects of molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides, which differ with respect to their AChE inhibitory potentials. Both molecules establish important interactions with the peripheral anionic site within the catalytic gorge of Torpedo californica AChE. However, only the major compound (–)-3-O-acetyl-cassine hydrochloride significantly interacts with the catalytic triad. Explicit-solvent molecular dynamic simulations were conducted in order to gain better understanding about the hypothetical interactions taking place between the semi-synthetic alkaloid molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides and AChE. The data obtained in this study indicated that (–)-3-O-acetyl-cassine hydrochloride is the most potent inhibitor of AChE possibly due to the favorable interactions of this molecule with the target protein, with lower desolvation cost. These results suggested that the size of the side chain has an effect on the inhibitory potential of the evaluated molecules and may represent the starting point for the development of new derivatives of (–)-3-O-acetyl-cassine hydrochloride, with a view to the discovery of new effective AChE inhibitors

Molecular docking and molecular dynamicsof semi-synthetic piperidine alkaloids as acetylcholinesterase inhibitors

A mistura dos derivados semissintéticos cloridrato da (–)-3-O-acetil-cassina e cloridrato da (–)-3-O-acetil-espectalina, preparada a partir da mistura dos alcalóides (–)-cassina e (–)-espectalina (4:1) obtida de Senna spectabilis, é um potente inibidor da acetilcolinesterase (AChE), assim justificando mais estudos moleculares. Neste sentido, estudos de docking e dinâmica moleculares foram conduzidos neste trabalho com o objetivo de adquirir uma compreensão mais profunda de todos os aspectos estruturais das moléculas cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina, as quais diferem em seus potenciais inibidores de AChE. Os dois derivados em estudo apresentaram diversas interações com o sítio periférico aniônico dentro da cavidade catalítica de AChE de Torpedo californica. Entretanto, somente o composto majoritário (–)-3-O-acetil-cassina mostrou interação com a tríade catalítica de maneira significativa. As simulações de dinâmica molecular utilizando água como solvente foram importantes para compreender as interações hipotéticas entre cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina com AChE. Os dados obtidos indicam que o composto (–)-3-O-acetil-cassina é o inibidor da enzima mais potente possivelmente devido às suas interações favoráveis com a proteína, com menor custo de dessolvatação. Estes resultados sugerem que o tamanho da cadeia lateral influencia no potencial inibitório das moléculas avaliadas e podem representar o ponto de partida para o desenvolvimento de novos derivados de (–)-3-O-acetil-cassina, objetivando a descoberta de inibidores de AChE mais eficazes.The mixture of semi-synthetic derivatives (–)-3-O-acetyl-cassine hydrochloride and (–)-3-O-acetyl-spectaline hydrochloride, prepared from the mixture of natural alkaloids (–)-cassine and (–)-spectaline (4:1) isolated from Senna spectabilis, has been shown to be a potent acetylcholinesterase (AChE) inhibitor, thereby prompting further molecular studies. In this sense, docking and dynamic molecular studies were carried out in this work, aiming to acquire a deeper understanding about all the structural aspects of molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides, which differ with respect to their AChE inhibitory potentials. Both molecules establish important interactions with the peripheral anionic site within the catalytic gorge of Torpedo californica AChE. However, only the major compound (–)-3-O-acetyl-cassine hydrochloride significantly interacts with the catalytic triad. Explicit-solvent molecular dynamic simulations were conducted in order to gain better understanding about the hypothetical interactions taking place between the semi-synthetic alkaloid molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides and AChE. The data obtained in this study indicated that (–)-3-O-acetyl-cassine hydrochloride is the most potent inhibitor of AChE possibly due to the favorable interactions of this molecule with the target protein, with lower desolvation cost. These results suggested that the size of the side chain has an effect on the inhibitory potential of the evaluated molecules and may represent the starting point for the development of new derivatives of (–)-3-O-acetyl-cassine hydrochloride, with a view to the discovery of new effective AChE inhibitors