Época de semeadura: um importante fator que afeta a produtividade da cultura da soja.

Temperatura do ar; Umidade do solo; Fotoperíodo.bitstream/item/65720/1/DOC34.pd

Exsudação de ácidos orgânicos por dois cultivares de arroz (Oryza sativa L.), submetidos a níveis tóxicos de alumínio.

Um dos principais mecanismos de tolerância ao Al, manifestado por várias espécies vegetais, baseia-se na capacidade que as plantas teriam de sintetizar e exsudar para o meio de cultivo certos ácidos orgânicos. Estes ácidos orgânicos seriam capazes de complexar a forma monomérica e mais tóxica do Al, diminuindo sua fitotoxicidade. A indução à exsudação parece ser especificamente regulada pelo Al e o sítio de sua secreção parece ser a zona distal de transição..

Amenização dos efeitos tóxicos do alumínio pela adição de ácidos orgânicos à solução nutritiva.

Um dos principais mecanismos de tolerância ao Al, manifestado por várias espécies vegetais, baseia-se na capacidade que as plantas teriam de sintetizar e exsudar para o meio de cultivo certos ácidos orgânicos. Estes ácidos orgânicos seriam capazes de complexar a forma monomérica e mais tóxica do Al no meio de cultivo, diminuindo sua absorção e, portanto, diminuindo a intensidade da fitotoxidade. A indução à exsudação parece ser especificamente regulada pelo Al e o sítio de sua secreção parece ser a zona distal de transição nas raízes..

Efeito do alumínio sobre parâmetros de crescimento em dois cultivares de arroz (Oryza sativa L.).

O Al absorvido pelas plantas tende a se acumular preferencialemente nos ápices radiculares, região da raiz tida como o principal sítio da ação inibitória do AL. Seja pela sua interferência na dinâmica do citoesqueleto, agindo sobre microtúbulos e filamentos de actina, seja pela inibição na absorção de Ca a inibição do alongamento radicular induzida por Al constitui um dos primeiros e mais importantes efeitos de cátion nas plantas..

Changes in antioxidative defense system of Stizolobium aterrimum and Canavalia ensiformis exposed to arsenic

The present work evaluated the antioxidant responses of Stilozobium aterrimum and Canavalia ensiformis after exposure to arsenic (As). Plants of these two species with the first pair of fully expanded cotyledonary leaves, grown in nutrient solution, pH 5.5, were treated with 0.0 and 1.5 mg.L-1 of As. After 5 days, the effects of As on lipid peroxidation and antioxidant enzymes were measured. Lipid peroxidation increased in both roots and leaves after As treatment, especially in S. aterrimum. Superoxide dismutase (SOD) activity increased in the two parts of the plants of both species with As treatment. Peroxidase (POX) activity, on the other hand, reduced with As treatment in S. aterrimum, but increased in C. ensiformis. Glutathione reductase (GR) increased in roots of both species, mainly in S. aterrimum. GR activity also increased in the leaves of C. ensiformis, but decreased in S. aterrimum. Under the experimental conditions of this study, C. ensiformis was considered to have antioxidant mechanisms slightly more efficient than S. aterrimum against reactive oxygen intermediates (ROIs). Keywords: arsenic, antioxidative mechanisms, lipid peroxidation, reactive oxygen intermediates

Optimizing a community-engaged multi-level group intervention to reduce substance use: an application of the multiphase optimization strategy

Abstract Background Rates of alcohol and illicit drug use (AIDU) are consistently similar across racial groups (Windsor and Negi, J Addict Dis 28:258–68, 2009; Keyes et al. Soc Sci Med 124:132–41, 2015). Yet AIDU has significantly higher consequences for residents in distressed communities with concentrations of African Americans (DCAA - i.e., localities with high rates of poverty and crime) who also have considerably less access to effective treatment of substance use disorders (SUD). This project is optimizing Community Wise, an innovative multi-level behavioral-health intervention created in partnership with service providers and residents of distressed communities with histories of SUD and incarceration, to reduce health inequalities related to AIDU. Methods Grounded in critical consciousness theory, community-based participatory research principles (CBPR), and the multiphase optimization strategy (MOST), this study employs a 2 × 2 × 2 × 2 factorial design to engineer the most efficient, effective, and scalable version of Community Wise that can be delivered for US$250 per person or less. This study is fully powered to detect change in AIDU in a sample of 528 men with a histories of SUD and incarceration, residing in Newark, NJ in the United States. A community collaborative board oversees recruitment using a variety of strategies including indigenous field worker sampling, facility-based sampling, community advertisement through fliers, and street outreach. Participants are randomly assigned to one of 16 conditions that include a combination of the following candidate intervention components: peer or licensed facilitator, group dialogue, personal goal development, and community organizing. All participants receive a core critical-thinking component. Data are collected at baseline plus five post-baseline monthly follow ups. Once the optimized Community Wise intervention is identified, it will be evaluated against an existing standard of care in a future randomized clinical trial. Discussion This paper describes the protocol of the first ever study using CBPR and MOST to optimize a substance use intervention targeting a marginalized population. Data from this study will culminate in an optimized Community Wise manual; enhanced methodological strategies to develop multi-component scalable interventions using MOST and CBPR; and a better understanding of the application of critical consciousness theory to the field of health inequalities related to AIDU. Trial registration ClinicalTrials.gov, NCT02951455 . Registered on 1 November 2016.https://deepblue.lib.umich.edu/bitstream/2027.42/143194/1/13063_2018_Article_2624.pd

Evaluation and comparison between methods of measurement of systolic blood pressure in healthy conscious cats

Após validação de dois diferentes métodos de mensuração de pressão arterial sistólica (PAS) não invasivos ou indiretos (oscilométrico e Doppler vascular) com o invasivo ou direto (cateterização arterial padrão ouro) em 12 gatos hígidos anestesiados de mesma faixa etária, os métodos não invasivos foram avaliados e comparados em 24 gatos hígidos e conscientes, divididos em quatro grupos de idade. Em cada animal, procedeu-se à mensuração da pressão pelos métodos Doppler e oscilométrico. O método oscilométrico foi o primeiro a ser realizado, e, logo em seguida, o método Doppler. Os valores considerados foram obtidos das médias de sete medidas consecutivas para cada método, com intervalo de 30 segundos entre elas. A primeira medida e as medidas discrepantes (variação ˃ 20% PAS), obtidas com sinais óbvios de estresse e/ou com movimentação do animal, foram descartadas. Os métodos de mensuração oscilométrico e Doppler, embora tenham apresentado médias estatisticamente diferentes em todos os grupos, quando comparados em cada grupo, apresentaram uma correlação significativa, alta e positiva. Ou seja, sempre que for obtido um valor elevado por um método, o mesmo fato ocorrerá com o outro método e vice-versa. Clinicamente, a diferença observada não é relevante, uma vez que a diferença média dos valores obtida pelos dois métodos, em cada grupo, foi menor que 1,1%.After two different validation systolic blood pressure measurement methods (PAS), not invasive or indirect (oscillometric and doppler vascular) with invasive or direct (arterial catheterization - Gold Standard) in 12 anesthetized healthy cats of the same age group, not invasive methods were evaluated and compared in 24 healthy conscious cats, divided into four age groups. In each animal, we proceeded to measure the pressure by Doppler and oscillometric methods. The oscillometric method was the first to be performed, and, shortly thereafter, the doppler method. The values considered were obtained from averages from seven consecutive measurements for each method with an interval of thirty seconds between them. The first measurement and disparate measurements (range ˃ 20% PAS) obtained with obvious signs of stress and / or animal movement were discarded. Methods of oscillometric and doppler measurement, although statistically different averages were shown in all groups when compared, each group showed a significant high positive correlation, meaning that when a high value is obtained by a method, the same occurs with the other method, and vice versa. Clinically, the observed difference is not relevant since the mean difference values obtained by the two methods, in each group was lower than 1.1%

Induction of CD4+CD25+FOXP3+ Regulatory T Cells during Human Hookworm Infection Modulates Antigen-Mediated Lymphocyte Proliferation

Hookworm infection is considered one of the most important poverty-promoting neglected tropical diseases, infecting 576 to 740 million people worldwide, especially in the tropics and subtropics. These blood-feeding nematodes have a remarkable ability to downmodulate the host immune response, protecting themselves from elimination and minimizing severe host pathology. While several mechanisms may be involved in the immunomodulation by parasitic infection, experimental evidences have pointed toward the possible involvement of regulatory T cells (Tregs) in downregulating effector T-cell responses upon chronic infection. However, the role of Tregs cells in human hookworm infection is still poorly understood and has not been addressed yet. In the current study we observed an augmentation of circulating CD4+CD25+FOXP3+ regulatory T cells in hookworm-infected individuals compared with healthy non-infected donors. We have also demonstrated that infected individuals present higher levels of circulating Treg cells expressing CTLA-4, GITR, IL-10, TGF-β and IL-17. Moreover, we showed that hookworm crude antigen stimulation reduces the number of CD4+CD25+FOXP3+ T regulatory cells co-expressing IL-17 in infected individuals. Finally, PBMCs from infected individuals pulsed with excreted/secreted products or hookworm crude antigens presented an impaired cellular proliferation, which was partially augmented by the depletion of Treg cells. Our results suggest that Treg cells may play an important role in hookworm-induced immunosuppression, contributing to the longevity of hookworm survival in infected people