Abstract COVID-19 is a pandemic disease caused by the SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) responsible for millions of deaths worldwide. Although the respiratory system is the main target of COVID-19, the disease can affect other organs, including the kidneys. Acute Kidney Injury (AKI), commonly seen in patients infected with COVID-19, has a multifactorial cause. Several studies associate this injury with the direct involvement of the virus in renal cells and the indirect damage stimulated by the infection. The direct cytopathic effects of SARS-CoV-2 are due to the entry and replication of the virus in renal cells, changing several regulatory pathways, especially the renin-angiotensin-aldosterone system (RAAS), with repercussions on the kallikrein-kinin system (KKS). Furthermore, the virus can deregulate the immune system, leading to an exaggerated response of inflammatory cells, characterizing the state of hypercytokinemia. The such exaggerated inflammatory response is commonly associated with hemodynamic changes, reduced renal perfusion, tissue hypoxia, generation of reactive oxygen species (ROS), endothelial damage, and coagulopathies, which can result in severe damage to the renal parenchyma. Thereby, understanding the molecular mechanisms and pathophysiology of kidney injuries induced by SARS-COV-2 is of fundamental importance to obtaining new therapeutic insights for the prevention and management of AKI.

RESUMO: O estresse causado por temperaturas extremas configura-se como um dos principais elementos que limitam a distribuição geográfica e o crescimento sazonal de diversas plantas, provocando severo atraso no seu desenvolvimento, reduzindo a taxa fotossintética e sinalizando a síntese de compostos de defesa. Diante das mudanças ambientais em curso e dos danos que essas mudanças podem causar na fisiologia e no crescimento das plantas, o objetivo deste trabalho foi compreender as interações entre temperatura, fisiologia e crescimento, bem como caracterizar o impacto que a alteração da temperatura exerce sobre o desenvolvimento inicial de Vernonia ferruginea Less. Para determinação de parâmetros fisiológicos e de crescimento, plântulas dessa espécie foram acondicionadas em câmaras de germinação com as temperaturas constantes dos tratamentos previamente ajustadas (10, 20, 25, 30 e 35 oC) por 60 dias. A faixa ótima de temperatura para crescimento inicial de V. ferruginea está entre 25 e 30 oC. O estresse causado pelas temperaturas subótimas e supraótimas afetou a homeostase celular e provocou atraso no crescimento e desenvolvimento das plântulas. Em situações estressantes, observou-se a inibição do crescimento e a ativação de mecanismos de resposta para a adaptação e manutenção da homeostase celular mediante o acúmulo do osmoprotetor prolina, e carboidratos solúveis. Adicionalmente, as plantas apresentaram desenvolvimento normal dentro de uma ampla faixa de temperatura, apesar do atraso no desenvolvimento, da alteração nas trocas gasosas e na síntese de substâncias relacionadas ao sistema de defesa.

ABSTRACT: Stress caused by extreme temperatures is one of the main elements that limit the geographical distribution and the seasonal growth of several plants, causing a severe delay in their development, reducing the photosynthetic rate and signaling the synthesis of defense compounds. Considering the current environmental changes and the damages that these changes can cause in plant physiology and growth, the objective of this work was to understand the interactions between temperature, physiology and growth, and to characterize the impact of temperature changes on the initial development of Vernonia ferruginea Less. Seedlings of this species were conditioned in germination chambers at previously adjusted constant temperatures (10, 20, 25, 30, and 35 oC) for sixty days, in order to evaluate physiological and growth parameters. The optimum temperature range for the initial growth of V. ferruginea is between 25 and 30 oC. The stress caused by sub-optimal and over-optimal temperatures affected cell homeostasis and caused a delay in the growth and development of seedlings. In stressful situations, growth inhibition and the activation of response mechanisms were observed for the adaptation and maintenance of cellular homeostasis through the accumulation of the proline osmoprotectant and soluble carbohydrates. Additionally, plants presented a normal development within a wide temperature range, despite the development delay, the change in gas exchanges and the synthesis of substances related to the defense system.

RESUMO: O uso repetitivo de herbicidas com o mesmo mecanismo de ação ocasiona a seleção de plantas daninhas resistentes, como o azevém. Tendo em vista a ocorrência de azevém (Lolium multiflorum) em eucaliptais, cultura na qual se usa o glyphosate, torna-se necessário estudar sua interferência. Neste trabalho, objetivou-se avaliar o efeito de densidades (0, 10, 20, 30 e 50 plantas m-2) de dois biótipos de azevém (resistente e suscetível ao glyphosate) em mudas de dois clones de Eucalyptus urograndis (I-144 e 1407). O delineamento experimental adotado foi em blocos casualizados com quatro repetições, seguindo esquema fatorial 2x5 para cada clone. Aos 0, 14, 28, 42, 56 e 70 dias após o transplante (DAT), foram avaliados a altura e o diâmetro dos clones, e aos 70 DAT, a área foliar e a biomassa seca de parte aérea do eucalipto e do azevém. Não houve interação entre os fatores biótipos e densidades para os clones, mas todas as características foram afetadas pelos fatores isoladamente. O aumento das densidades do azevém alterou todas as características avaliadas nos clones, sendo a área foliar dos clones de eucaliptos a mais afetada, com reduções de até 72%. O biótipo resistente foi menos competitivo, ocasionou reduções nos clones de até 39% em área foliar, 5% em diâmetro e 1% em altura, ao passo que o biótipo suscetível ocasionou reduções de 51%, 13% e 6%, respectivamente. Desse modo, a densidade tolerável pela cultura dos biótipos resistentes pode ser maior que a dos biótipos suscetíveis.

ABSTRACT: The repetitive use of herbicides with the same mechanism of action causes the selection of resistant weeds, such as ryegrass. Considering the occurrence of ryegrass (Lolium multiflorum) in eucalyptus, a crop on which glyphosate is used, it is necessary to study its interference. The objective of this study was to evaluate the effect of densities (0, 10, 20, 30 and 50 plants m-2) of two ryegrass biotypes (resistant and susceptible to glyphosate) on seedlings of two eucalyptus clones (I-144 and 1407). The used experimental design was in randomized blocks with four replications, following a 2 x 5 factorial arrangement for each clone. The height and diameter of the clones were evaluated at 0, 14, 28, 42, 56 and 70 days after transplantation (DAT), and at 70 DAT, the leaf area and dry biomass of eucalyptus and ryegrass were also evaluated. There was no interaction between the biotype and densities factors for the clones, but all characteristics were affected by the factors separately. The increase in ryegrass densities affected all the characteristics evaluated in the clones, being the leaf area of the eucalyptus clones the most affected one, with reductions of up to 72%. The resistant biotype was less competitive, causing reductions in clones of up to 39% in leaf area, 5% in diameter and 1% in height, while the susceptible biotype resulted in reductions of 51%, 13% and 6%, respectively. Thus, the tolerable density by the culture to the resistant biotypes may be greater than that of the susceptible biotypes.

RESUMO Este trabalho avaliou os efeitos da radiação ionizante sobre as características físico-químicas e sensoriais de batata inglesa da cultivar Ágata (Solanum tuberosum L.), incluindo brotamento e a deterioração, com o objetivo final de aumentar a vida de prateleira. Para isso, quatro grupos de amostras foram colhidos na fase de maturação. Três destes grupos foram separadamente expostos a uma fonte de Co-60, recebendo respectivas doses de 0,10, 0,15 e 2,00 kGy, enquanto que o grupo não irradiado foi mantido como controle. Todas as amostras foram armazenadas durante 35 dias a 24 ° C (± 2) e a 39% de umidade relativa. Os seguintes aspectos foram avaliados: brotamento, podridão, perda de peso, textura, cor da polpa, umidade, aparência externa e interna, aroma, teor de sólidos solúveis, acidez titulável, vitamina C, proteínas, amido e glicose. Os resultados indicaram que a dose de 0,15 kGy foi a mais eficaz para reduzir a germinação e perdas pós-colheita, sob as condições estudadas.

ABSTRACT This work evaluated the effects of ionizing radiation on the physico-chemical and sensory characteristics of the potato cultivar Ágata (Solanum tuberosum L.), including budding and deterioration, with the end goal of increasing shelf life. For this, four groups of samples were harvested at the maturation stage. Three of them were separately exposed to a Co-60 source, receiving respective doses of 0.10, 0.15 and 2.00 kGy, while the non-irradiated group was kept as a control. All samples were stored for 35 days at 24 °C (± 2) and at 39% relative humidity. The following aspects were evaluated: budding, rot, loss of weight, texture, flesh color, moisture, external and internal appearance, aroma, soluble solids, titratable acidity, vitamin C, protein, starch and glucose. The results indicated that 0.15 kGy was the most effective dose to reduce sprouting and post-harvest losses, under the conditions studied.