Interactions between indole-3-acetic acid (IAA) with a lectin from Canavalia maritima seeds reveal a new function for lectins in plant physiology

AbstractIndole-3-acetic acid (IAA) bound is considered a storage molecule and is inactive. However, some studies have proposed an additional possible regulatory mechanism based on the ability of lectins to form complexes with IAA. We report the first crystal structure of ConM in complex with IAA at 2.15 Å resolution. Based on a tetrameric model of the complex, we hypothesize how the lectin controls the availability of IAA during the early seedling stages, indicating a possible new physiological role for these proteins. A free indole group is also bound to the protein. The ConM interaction with different forms of IAA is a strategy to render the phytohormone unavailable to the cell. Thus, this new physiological role proposed for legume lectins might be a novel mechanism by which IAA levels are decreased in addition to the destruction and formation of new complexes in the later stages of seed germination

Germinação e crescimento inicial de girassol (Helianthus annuus L.) sob diferentes substratos submetidos a estresse salino / Germination and initial growth of sunflower (Helianthus annuus L.) under different substrates submitted to saline stress

O girassol (Helianthus annuus L.) é uma espécie de grande importância agrícola, dentre as plantas de ciclo curto, apresenta características agronômicas importantes, como maior resistência à seca, ao frio e ao calor, o que lhe confere grande potencialidade de cultivo em diferentes regiões do país. Entre outros usos, suas sementes podem ser utilizadas para fabricação de ração animal, extração de óleo de alta qualidade para consumo humano e como matéria-prima para a produção de biodiesel. O cultivo em substratos demonstra um avanço na produção de mudas de várias espécies de interesse agronômico, por fornecer mais nutrientes, atenuar afeitos nocivos e consequentemente proporcionar melhores condições para o desenvolvimento da planta. A utilização de água de baixa qualidade é um dos fatores limitantes na produção de várias culturas, sendo o Nordeste uma das regiões mais prejudicadas por esse fator. O presente trabalho teve como objetivo avaliar o desenvolvimento inicial de plântulas de girassol em diferentes substratos irrigados com água salina. O experimento foi conduzido em viveiro telado da Unidade de Execução de Pesquisa da Embrapa Tabuleiros Costeiros, situada no Centro de Ciências Agrárias da Universidade Federal de Alagoas, no Município de Rio Largo. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 5x3 com cinco dosagens salinas (0,0; 2,5; 3,5; 4,5 e 5,5 dSm-1), três tipos de substratos (terra preta, torta de filtro e substrato industrial) e quatro repetições. Foram avaliadas as seguintes variáveis: porcentagem de emergência das plântulas, índice de velocidade emergência, número de folhas, altura das plântulas, diâmetro do caule, massa úmida e massa seca total da plântula. Constatou-se que os níveis mais elevados de salinidade do solo reduziram o desenvolvimento das plântulas de girassol, havendo interação para o fator substrato, sendo o Terra Preta o melhor avaliado

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

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

α-, β-caroteno e α-tocoferol em algas marinhas in natura α- and β-carotene, and α-tocopherol in fresh seaweeds

O objetivo deste trabalho foi avaliar o potencial de 32 espécies de algas marinhas das divisões Chlorophyta, Rhodophyta e Phaeophyta como fontes de &#945;- e &#946;-caroteno e &#945;-tocoferol. Todas as clorofíceas analisadas apresentaram &#945;- e &#946;-caroteno. Os teores máximo e mínimo de &#945;-caroteno foram detectados nas espécies do gênero Caulerpa e em Codium decorticatum, respectivamente; e &#946;-caroteno foi mais baixo em Caulerpa mexicana e mais elevado em Ulva fasciata. Dentre as rodofíceas, 11 espécies apresentaram &#945;-caroteno, com máximo em Botryocladia occidentalis. &#946;-caroteno foi encontrado em todas as algas vermelhas analisadas com teores mínimo e máximo em Gracilaria caudata e Bryothamnion triquetrum, respectivamente. As feofíceas apresentaram apenas &#946;-caroteno, com mínimo e máximo em Dictyopteris delicatula e Padina gymnospora, respectivamente. Na divisão Chlorophyta, &#945;-tocoferol, foi máximo em Codium decorticatum e mínimo em Caulerpa prolifera. Na Rhodophyta, 12 espécies apresentaram &#945;-tocoferol com teor máximo em Enantiocladia duperreyi. Na Phaeophyta, &#945;-tocoferol foi encontrado com valores mínimo e máximo em Lobophora variegata e Dictyota dichotoma, respectivamente.<br>The aim of this work was to evaluate the potential of 32 marine macro algae species, members of Chlorophyta, Rhodophyta and Phaeophyta, as sources of a-carotene, b-carotene and a-tocopherol. Both b-carotene and a-carotene were found in all species of green macroalgae analyzed. The maximum content of a-carotene was detected in algae belonging to Caulerpa genus and the minimum in Codium decorticatum. The amount of b-carotene found was minimum in Caulerpa mexicana and maximum in Ulva fasciata. Among the Rhodophyta species, eleven contain a-carotene, the maximum content was found in Botryocladia occidentalis. b-Carotene was found in all red macroalgae analyzed presenting the lowest and highest values in Gracilaria caudata and Bryothamnion triquetrum, respectively. Species of Phaeophyta contained b-carotene but no a-carotene. The lowest value for b-carotene was found in Dictyopteris delicatula and the highest in Padina gymnospora. In Chlorophyta, the amount of a-tocopherol was maximum in Codium decorticatum and minimum in Caulerpa prolifera. In Rhodophyta, twelve species contained a-tocopherol, the highest value was found in Enantiocladia duperreyi. a-Tocopherol was detected in all Phaeophyta species analyzed. The highest and lowest values were found in Lobophora varigata and Dictyota dichotoma, respectively

<b><i>In vitro</i> evaluation of antioxidant activity of methanolic extracts obtained from seaweeds endemic to the coast of Ceará, Brazil

The aim of the present research was to evaluate the antioxidant activity of six species of marine algae (Caulerpa cupressoides, Ulva fasciata, Amansia multifida, Cryptonemia crenulata, Dictyota dichotoma and Sargassum vulgare) collected in 2011 at Paracuru Beach, Ceará State, Brazil. Methanol extracts were prepared from oven-dried algae and used to measure total phenolic content (TPC) using the Folin- Ciocalteu colorimetric method. In vitro antioxidant activity of the algal extracts (12.5 to 100 mg mL-1) was analyzed by DPPH radical scavenging, ferric-reducing antioxidant power (FRAP) and ferrous ion chelation (FIC). BHA and EDTA were used as positive controls. Based on the standard curve of gallic acid, TPC values ranged from 10.49 to 19.94 mg gallic acid equivalents (GAE) g-1 of extract. DPPH results of algal extracts at all concentrations tested remained between 53.96 and 64.96%, lower than the positive control (BHA). All species showed little FRAP activity (less than 0.1) when compared to BHA. FIC above 20% was detected only in the extract from U. fasciata (100 mg mL-1), while all the others had activities below 17%. The activity of EDTA ranged from approximately 48 (12.5 mg mL-1) to 98% (100 mg mL-1). These results allow us to consider the algae species studied as potentially promising sources of natural antioxidants