Intracellular reactive oxygen species trafficking participates in seed dormancy alleviation in Arabidopsis seeds.

Reactive oxygen species (ROS) release seed dormancy through an unknown mechanism. We used different seed dormancy-breaking treatments to decipher the dynamics and localization of ROS production during seed germination. We studied the involvement of ROS in the breaking of Arabidopsis seed dormancy by cold stratification, gibberellic acid (GA3 ) and light. We characterized the effects of these treatments on abscisic acid and gibberellins biosynthesis and signalling pathways. ROS, mitochondrial redox status and peroxisomes were visualized and/or quantified during seed imbibition. Finally, we performed a cytogenetic characterization of the nuclei from the embryonic axes during seed germination. We show that mitochondria participate in the early ROS production during seed imbibition and that a possible involvement of peroxisomes in later stages should still be analysed. At the time of radicle protrusion, ROS accumulated within the nucleus, which correlated with nuclear expansion and chromatin decompaction. Taken together, our results provide evidence of the role of ROS trafficking between organelles and of the nuclear redox status in the regulation of seed germination by dormancy.

Caracterização de Staphylococcus aureus isolados da barra de mão de carrinhos e alças de cestas de supermercados / Characterization of Staphylococcus aureus Isolated of shopping carts hand bars and handles of handheld shopping baskets in supermarkets

Staphylococcus aureus é um dos agentes patogênicos mais notórios, sendo responsável por 45% das toxinfecções em todo o mundo. Um dos grandes problemas atuais é o desenvolvimento de cepas resistentes a antibióticos. Considerando a importância da disseminação desses micro-organismos na comunidade, o presente trabalho teve por objetivo determinar a presença de Staphylococcus aureus na barra de mão dos carrinhos e alças de cestas de supermercados da cidade de Campo Mourão - PR, e caracterizar a susceptibilidade dos isolados à oxacilina. Foram analisadas 120 amostras, sendo 60 coletadas das barras de mão de carrinhos e 60 coletadas das alças de cestas. Esse micro-organismo foi isolado em 75 amostras (62,5%), sendo que, desse total, 35 amostras (46,7%) foram isoladas de carrinhos e 40 (53,3%) de cestas de compras. As amostras positivas para Staphylococcus aureus foram submetidas aos testes de susceptibilidade, pelo método de disco-difusão, à oxacilina (cefoxitina) e todas as amostras foram consideradas sensíveis a essa droga. Constatou que as barras de mãos e as alças de cestas de supermercados, podem ser consideradas como fômites, na disseminação de Staphylococcus aureus, sendo de extrema importância a higienização desses objetos, a fim de diminuir os riscos de contaminação na comunidade.

Staphylococcus aureus is one of the most notorious pathogens, accounting for 45% of intoxications worldwide. One of the major problems today is the development of antibiotic-resistant strains. Considering the importance of dissemination of these microorganisms in the community, this study aimed to determine the presence of Staphylococcus aureus in shopping carts hand bars and handles of handheld shopping baskets in supermarkets from the city of Campo Mourão ­ PR, and characterize the susceptibility of isolates to oxacillin. One hundred twenty samples, of which 60 collected from bars hand stands and collected 60 of the handles of baskets. This micro-organism was isolated in 75 samples (62.5%), and of this total, 35 samples (46,7%) were isolated from carts and 40 (53,3%) of shopping baskets. The positive samples for Staphylococcus aureus were submitted to susceptibility testing by the disk diffusion method to oxacillin (cefoxitin) and all samples were found to be sensitive to this drug. It found that the bars of hands and the handles of supermarket baskets can be considered as fomites in the dissemination of Staphylococcus aureus, being extremely important to sanitization these objects in order to reduce the risk of contamination in the community.