Evaluation of the Biotechnological Potential of Monteverdia salicifolia (Mart ex. Reissek) Biral

Plant extracts are a good alternative of reducing agents in the synthesis of metal nanoparticles. In this paper, we report the evaluation of the cytotoxic activity against T3 cell lines of the ethanolic extract of Monteverdia salicifolia (Mart ex. Reissek) Biral roots (MS) as well as a green one-pot route of synthesis of silver nanoparticles (AgNPs) using that extract as reducing and stabilizing agent. The extract exhibited dose dependent activity. The smallest particle size (48.01 nm) was achieved in just 25 minutes by employing a temperature of 65 °C and AgNO3 and MS concentrations equal to 0.9 mmol.L−1 and 0.67 mg.mL−1, respectively. The AgNPs-MS nanocomposite was characterized by UV–vis spectroscopy, FEG microscope and zeta potential, which proved that MS was effective at reducing and capping the AgNPs. In order to emphasize the advantage of the methodology applied in this synthesis, it was compared to a usual procedure using NaBH4 as a reducing agent and the greenness analysis was also carried out, using the Green Star. DOI: http://dx.doi.org/10.17807/orbital.v13i2.154

A importânciados modelos didáticos tridimensionais para o ensino de ciências / The importance of three-dimensional teaching models for science teaching

Atualmente o ensino de ciências vem apresentando diversos desafios em sua efetivação, requerendo novos métodos que permitam diferentes possibilidades didáticas e potencializem o processo de ensino e aprendizagem das ciências biológicas. Nesse contexto destaca-se a utilização de modelos didáticos tridimensionais que possibilitam aos estudantes conhecer de forma muito ampliada estruturas microscópicas. Aexperiênciaque gerou este relato ocorreu dentro do estágio supervisionado, objetivou observar em que medida a inserção de modelos didáticos tridimensionais potencializa a aprendizagem. Esta atividade de ensino e pesquisa desenvolveu-se em uma turma do 6º ano de uma escola pública de Juazeiro do Norte-CE, ao se trabalhar em sala de aula diferentes modelos didáticos de células animais e vegetais. As atividades constaram de três momentos: oficina sobre o conteúdo sobre as estruturas celulares;observação das estruturas celularese suas respectivas funções; e gincana entre equipes abordando as estruturas celulares estudadas. A atividade também objetivou desenvolver pesquisa para mensurar a importância dessa metodologia para a aprendizagem, como forma de refletir sobre a prática pedagógica. Diante da prática realizada percebeu-se que a utilização de modelos tridimensionais além de tornar a aula mais atrativa, despertou a curiosidade e o interesse dos estudantes, que atentos participaram ativamente da aula, em especial nos momentos que se utilizaram os modelos tridimensionais. Pode-se considerar que as utilizações desses modelos sãoimportantes para o processo tanto de ensino quanto de aprendizagem das ciências biológicas, em virtude de despertar a curiosidade e atenção dos alunos para desenvolver aprendizagem significativa

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,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

Effect of the water stress on the chemical composition and antimicrobial activity of the essential oil of three species of Leptospermum J. R. Forst & G. Forst (Myrtaceae)

O presente trabalho visou avaliar o efeito do estresse hídrico sobre o teor e a composição química do óleo essencial das espécies Leptospermum flavescens, L. madidum ssp sativum e L. petersonii cultivadas no município de Viçosa, Minas Gerais, Brasil. São apresentados dados relativos à composição química dos óleos essenciais das folhas dessas espécies, além da composição do óleo essencial e dos voláteis liberados pelas flores de L. petersonii. A identificação dos compostos dos óleos essenciais foi feita empregando-se cromatografia gasosa acoplada a espectrometria de massa. Para a determinação dos voláteis das flores utilizou-se a técnica de headspace - microextração em fase sólida. As espécies de Leptospermum apresentaram padrões diferenciados na composição do óleo essencial. Observou-se que após a ocorrência de chuvas houve redução no teor do óleo essencial para L. madidum ssp sativum e um ligeiro aumento para as demais. O componente majoritário do óleo essencial de L. flavescens foi nerolidol (55,1 ± 3,4% na estiagem; 68,6 ± 1,8% no período chuvoso). Em L. madidum ssp sativum no período de estiagem, os componentes encontrados em maior proporção foram β-pineno (18,5 ± 0,5%), α-pineno (15,2 ± 0,7%), α-humuleno (10,2 ± 0,2%), 1,8-cineol (7,1 ± 0,7%) e trans-cariofileno (5,8 ± 0,01%). Com a ocorrência de precipitação, as concentrações desses compostos foram alteradas, sendo α-humuleno o componente majoritário (30,8 ± 1,2%), seguido de trans-cariofileno (11,9 ± 0,1%). Tanto no óleo essencial das flores quanto das folhas de L. petersonii os principais componentes foram citronelal, neral e geranial, sendo que nas flores as concentrações foram de 35,0 ± 0,5%, 16,5 ± 2,1% e 26,1 ± 0,3%, respectivamente. Nas folhas, as concentrações encontradas foram de 33,9 ± 0,8% na estação seca e 26,5 ± 1,0% na estação chuvosa para citronelal, 22,7 ± 0,7% e 23,5 ± 1,5% para neral, 29,8 ± 0,4% e 32,8 ± 0,5% para geranial. Os principais componentes encontrados nos voláteis liberados pelas flores de L. petersonii foram citronelal (27,4 ± 1,6%) e β-citronelol (22,1 ± 3,6%). Observou-se que o efeito do estresse hídrico sobre o teor e a composição química dos óleos voláteis é diferente para cada uma das espécies. Avaliou-se a atividade dos óleos essenciais obtidos contra as bactérias Bacillus cereus, Staphylococcus aureus e Escherichia coli. Tanto o óleo de L. flavescens como o de L. madidum ssp sativum apresentaram atividade contra os dois primeiros microorganismos, porém foram ineficazes contra E. coli. O óleo de L. petersonii inibiu o crescimento de todos os microorganismos testados. Os resultados obtidos mostram que os óleos essenciais de Leptospermum podem ser uma alternativa no controle dessas bactérias que deterioram os alimentos.This study aimed to evaluate the effect of the water stress on the yield and chemical composition of the of Leptospermum flavescens, L. madidum ssp sativum and L. petersonii essential oil growing in Viçosa, state of Minas Gerais, Brazil. Result on the compared chemical composition of the leaves essential oil of these species and the composition of the essential oil and the volatile release from L. petersonii flowers. Compound identification was done by gas chromatography - mass spectromety; for determination of the volatile compounds from flowers was utilized headspace solid-phase microextraction. The Leptospermum species showed differences within their relative essential oil composition. After rainfall, there was a reduction in the yield of essential oil for L. madidum ssp sativum and a slightly increase for others. The major constituent found in the L. flavescens essential oil was nerolidol (55.1 ± 3.4% in drought; 68.6 ± 1.8% in the rainy period). In the L. madidum ssp sativum essential oil in the drought period, the main compounds were β-pinene (18.5 ± 0.5%), α-pinene (15.2 ± 0.7%), α-humulene (10.2 ± 0.2%), 1,8-cineol (7.1 ± 0.7%) and transcariophyllene (5.8 ± 0.01%). With rainfall, the concentration these compounds was changed; α-humulene (30.8 ± 1.2%) and trans- cariophyllene (11.9 ± 0.1%) were the main compounds. As so flowers essential oil as leaves of the L. petersonii, the main compounds found were citronellal, neral and geranial; in the flowers the concentration were 35.0 ± 0.5%, 16.5 ± 2.1%, and 26.1 ± 0.3%, respectively. The concentration found in the leaves were 33.9 ± 0.8% in drought and 26.5 ± 1.0% in the rainy period for citronellal, 22.7 ± 0.7% and 23.5 ± 1.5% for neral, 29.8 ± 0.4% and 32.8 ± 0.5% for geranial. The main compounds in the volatile emitted for L. petersonii flowers were citronellal (27.4 ± 1.6%) and β-citronellol (22.1 ± 3.6%). The effect of water stress on the yield and chemical composition of the volatile oils is different for each species. It was evaluated the activity of the essential oils against Bacillus cereus, Staphylococcus aureus and Escherichia coli. The L. flavescens and L. madidum ssp sativum oils exhibited activity against Gram-positive bacteria, but were inactive against E. coli. The L. petersonii essential oil showed activity against all tester microorganisms tested. The results showed that the Leptospermum essential oils could be an efficient alternative for the control of foodborne bacteria

Salicassin, an unprecedented chalcone diterpene adduct and a quinone methide triterpenoid from Maytenus salicifolia.

In continuation of our work on Maytenus salicifolia, we report herein the isolation and structuralelucidation of two new compounds, salicassin (1), a diterpene-chalcone adduct with an unprecedented C-framework, and (16b)-16-hydroxypristimerin (2), a quinone methide triterpenoid. Their structures wereelucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques (COSY,ROESY, HSQC, and HMBC). In addition, 22 known compounds were isolated and characterized bycomparison of their spectra with reported data. Compound 2, structurally related to the well knowncytotoxic quinone methide triterpenoids, exhibited an antiproliferative effect on HeLa, A-549, and HL-60 human cell lines, with IC50values of 2.2, 3.2, and 2.7 mm, respectively