No abstract

The development of harmless substances to replace biocide-based coatings used to prevent or manage marine biofouling and its unwanted consequences is urgent. The formation of biofilms on submerged marine surfaces is one of the first steps in the marine biofouling process, which facilitates the further settlement of macrofoulers. Anti-biofilm properties of a synthetic polyphenolic compound, with previously described anti-settlement activity against macrofoulers, were explored in this work. In solution this new compound was able to prevent biofilm formation and reduce a pre-formed biofilm produced by the marine bacterium, Pseudoalteromonas tunicata. Then, this compound was applied to a marine coating and the formation of P. tunicata biofilms was assessed under hydrodynamic conditions to mimic the marine environment. For this purpose, polyurethane (PU)-based coating formulations containing 1 and 2 wt.% of the compound were prepared based on a prior developed methodology. The most effective formulation in reducing the biofilm cell number, biovolume, and thickness was the PU-based coating containing an aziridine-based crosslinker and 2 wt.% of the compound. To assess the marine ecotoxicity impact of this compound, its potential to disrupt endocrine processes was evaluated through the modulation of two nuclear receptors (NRs), peroxisome proliferator-activated receptor γ (PPARγ), and pregnane X receptor (PXR). Transcriptional activation of the selected NRs upon exposure to the polyphenolic compound (10 µM) was not observed, thus highlighting the eco-friendliness towards the addressed NRs of this new dual-acting anti-macro- and anti-microfouling agent towards the addressed NRs.

ABSTRACT The spatial arrangement of plants in the cultivation area is a factor that directly influences grain yield, since the best arrangement can result in the greater use of water, light and nutrients. The aim of the study was to evaluate the agronomic performance of sorghum sown in double row spacing in the Brazilian Cerrado. For this purpose, field experiments were conducted in the 2018 and 2019 seasons in a complete block design with a factorial scheme of 2 x 5. There were four replications, using two row spacing: traditional (0.50 m) and double rows (0.25 m/0.75 m) and five plant populations: 120, 180 (recommended), 240, 300 and 360 thousand, plants ha-1. Morphological characteristics, yield components and grain yield were evaluated using joint data analysis for the two years of study. In 2018, due to lower rainfall during the crop season, the use of a double row arrangement presented grain yield lower than traditional spacing. On the other hand, in 2019, the year with the best water distribution, the yield was superior to that of 2018. The increase in plant population per hectare increased the yield of sorghum grains, with gains of up to 24% in relation to the recommended population of 180 thousand plants ha-1, demonstrated that the densification in this crop can be a promising technique as long as its cost/benefit is considered.

Capim-amargoso e milho voluntário destacam-se como as principais espécies invasoras no cultivo da soja ocasionando perdas de produtividade devido a matocompetição. Este trabalho teve como objetivo estudar herbicidas pré-emergentes para o controle do capim-amargoso (Digitaria insularis) e do milho voluntário. Para tanto, foi realizado experimento em casa de vegetação, no delineamento experimental inteiramente casualizado, com seis tratamentos e quatro repetições, sendo os tratamentos: S-metolachlor (1152 g ha-1), diclosulam (25,2 g ha-1), imazethapyr (80 g ha-1), flumioxazin (60 g ha-1), [imazethapyr + flumioxazin] [106 + 50 g ha-1] e testemunha sem herbicida. As aplicações foram realizadas imediatamente após a semeadura das espécies, procedendo o umedecimento do solo contido nos vasos. Foi avaliado a porcentagem de controle aos 14, 21 e 28 dias após a emergência (DAE), número de plantas emergidas e massa seca das plantas aos 28 DAE. Os herbicidas que proporcionaram maiores níveis de controle sobre plantas de capim-amargoso quando aplicados em pré-emergência foram S-metolachlor (1152 g ha-1) e flumioxazin (60 g ha-1). Para o controle do milho voluntário [imazethapyr + flumioxazin] [106 + 50 g ha-1] e diclosulam (25,2 g ha-1) consistiram como as melhores alternativas. Para o controle das duas espécies simultaneamente, [imazethapyr + flumioxazin] mostrou-se eficiente, tal como, a possibilidade da associação entre os herbicidas (S-metolachlor + diclosulam) e (flumioxazin + diclosulam).

Hazard assessment strategies are often supported by extrapolation of damage probabilities, regarding chemical action and species susceptibilities. Yet, growing evidence suggests that an adequate sampling of physiological responses across a representative taxonomic scope is of paramount importance. This is particularly relevant for Nuclear Receptors (NR), a family of transcription factors, often triggered by ligands and thus, commonly exploited by environmental chemicals. Within NRs, the ligand-induced Ecdysone Receptor (EcR) provides a remarkable example. Long regarded as arthropod specific, this receptor has been extensively targeted by pesticides, seemingly innocuous to non-target organisms. Yet, current evidence clearly suggests a wider presence of EcR orthologues across metazoan lineages, with unknown physiological consequences. Here, we address the state-of-the-art regarding the phylogenetic distribution and functional characterization of metazoan EcRs and provide a critical analysis of the potential disruption of such EcRs by environmental chemical exposure. Using EcR as a case study, hazard assessment strategies are also discussed in view of the development of a novel “precision hazard assessment paradigm.