Seletividade de herbicidas a cinco tipos de gramas Herbicide selectivity to five species of turfgrasses

Dentre as opções de controle de plantas daninhas em gramados, destaca-se o uso de herbicidas, porém poucas informações existem na literatura sobre a sua seletividade a gramados. Assim, foi desenvolvida a presente pesquisa em casa de vegetação da ESALQ - Piracicaba, com o objetivo de testar a seletividade de herbicidas aplicados em pré-plantio (sulfentrazone a 1,4 kg i.a. ha-1 e oxadiazon a 1,0 kg i.a. ha-1) e em pós-emergência (halosulfuron a 112,5 g i.a. ha-1, 2,4-D a 2,010 kg i.a. ha-1 e MSMA a 2,4 kg i.a. ha-1), em cinco espécies de gramas (família Poaceae): são-carlos (Axonopus affinis), esmeralda (Zoysia japonica), bermuda (Cynodon dactylon), zoysia (Zoysia matrella) e santo-agostinho (Stenotaphrum secundatum). As conclusões gerais deste trabalho de pesquisa foram de que a seletividade de herbicidas aos diversos tipos de grama é função principalmente da espécie de grama e do tipo e da dose do herbicida aplicado. Dentre os herbicidas testados, destacam-se como mais seletivos o halosulfuron na dose de 112,5 g i.a. ha-1 e o 2,4-D na de 2,010 kg i.a. ha-1; as espécies de grama do gênero Zoysia (esmeralda [Z. japonica] e zoysia [Z. matrella]), de maneira geral, são mais tolerantes aos herbicidas testados nesta pesquisa.<br>Among the weed control options, herbicide is certainly one to be considered for weed control in turfgrass; however, little has been published about herbicide selectivity, specially under Brazilian landscape conditions. Therefore, this research was conducted at USP/ESALQ, Piracicaba-SP, Brazil, to evaluate herbicide selectivity to turfgrass of pre-planting application herbicides (sulfentrazone at 1.4 kg a.i.ha-1 and oxadiazon 1.0 kg a.i.ha-1) and post-emergence application herbicides (halosulfuron at 112.5 g a.i.ha-1, 2,4-D at 2.010 kg a.i.ha-1 and MSMA at 2.4 kg a.i.ha-1), in five species of turfgrass: Axonopus affinis Chase, Zoysia japonica, Cynodon dactylon, Zoysia matrella and Stenotaphrum secundatum. It was concluded that herbicide selectivity to the turfgrass species studied is a function of the grass species and herbicide type and rate sprayed. Among the tested herbicides, halosulfuron at 112.5 g a.i.ha-1 and 2,4-D at 2010 g a.i.ha-1 were the most selective ones, and the grass species of the genus Zoysia (Z. aponica and Z. matrella), were, in general, the most tolerant to all the herbicides tested

Infecção por enterovirus humanos em cães errantes. Alguns aspectos de interesse em Saúde Pública

To investigate the possible role of domestic animals as reservoirs of human enteroviruses, we studied 212 stray dogs captured in different areas of the municipality of São Paulo. The captured animals were divided into 19 groups of 10 to 20 dogs each; faeces of 126 of the 212 dogs were processed for enterovirus isolation. The following viruses were isolated from 12 dogs: poliovirus type 1 (2 dogs), poliovirus type 3 (1 dog), echovirus type 7 (8 dogs) and echovirus type 15 (1 dog). Of the 12 infected animals, four had specific homotypic neutralizing antibody titres >; 16. All 212 animals were tested for the presence of neutralizing antibodies to human enteroviruses. The frequency of neutralizing antibodies present in titres of >; 16 was 10.3%, 3,8% and 4.3% for vaccinal prototypes of polioviruses 1, 2 and 3 respectively; 1,9%, 1.4% and 1.5% for wild prototypes of the same viruses, 11.3% for echovirus 7, and 2.4% for echovirus 15. The proportion of dogs with neutralizing antibodies varied with the virus studied. Some indication of the susceptibility of dogs to infection with human enteroviruses was demonstrated, and the importance of this fact for the Plan for Global Eradication of the Wild Poliovirus is discussed.Foram estudados 212 cães errantes, capturados em áreas periféricas do município de São Paulo, com o objetivo de investigar o possível papel desses animais como reservatórios de enterovírus humanos. Os animais capturados foram divididos em 19 grupos compostos por 10 a 20 animais cada um. Foram efetuadas tentativas de isolamento em amostras de fezes em 126/212 cães, obtendo-se resultados positivos em 12 deles, assim distribuídos: poliovirus tipo 1 (dois cães), poliovírus tipo 3 (um cão), echovirus tipo 7 (oito cães) e echovirus tipo 15 (um cão). Dos 12 animais infectados, quatro apresentaram anticorpos neutralizantes homotípicos com títulos >; 16. Todos os 212 cães foram submetidos a pesquisa de anticorpos neutralizantes contra enterovírus humanos. As frequências de anticorpos neutralizantes com títulos >; 16 foram de 10,3%, 3,8% e 4,3%, respectivamente, contra protótipos vacinais de poliovírus 1, 2 e 3 e 1,9% 3,8% e 4,3% contra protótipos "selvagens" dos mesmos vírus; de 11,3% contra echovírus tipo 7 e de 2,4% contra echovírus tipo 15. São discutidos dados sugestivos da suscetibilidade de cães à infecção por enterovírus humanos e a possível importância desse fato para o Plano de Erradição do Poliovírus "Selvagem"

Banco de sementes de aveia preta no solo sob dois sistemas de manejo Soil seed bank of black oat in two management systems

As sementes de aveia preta (Avena strigosa Schreb.) possuem a capacidade de permanecer viáveis no solo de um ano de cultivo para outro. Dessa forma, o objetivo do trabalho foi avaliar o número de sementes de aveia preta resultantes de dois sistemas de manejo (colheita e ressemeadura natural), que poderão formar o banco de sementes do solo. Os ensaios foram realizados no município de Jari - RS, em uma área cultivada sob o sistema de "plantio direto". Foram coletadas 50 amostras em cada sistema de manejo, com um espaçamento de 10x20m, utilizando um amostrador de diâmetro de 0,05m e uma profundidade de 0,1m. O levantamento do número de sementes e da emergência das plântulas foi realizado no Laboratório Didático da Faculdade de Agronomia Eliseu Maciel (UFPel). Constatou-se que a colheita e a ressemeadura natural possibilitam a presença de sementes no solo por área, em quantidades superiores à indicada para a semeadura. Com a colheita, a área fica heterogênea em número de sementes no solo e em plântulas emergidas. A ressemeadura natural resulta em uma grande quantidade de sementes no solo e formação de plântulas.<br>The black oat (Avena strigosa Schreb.) seeds are able to remain alive in soil from a culture to another. The objective of this study was to evaluate the number of black oat seeds resulting from two management, harvesting, and natural reseeding, which could form the seed bank of soil. The experiments were conducted in Jari-RS, Brazil, the cultivation system is "No Tillage". Were collected 50 samples in each management, at a spacing of 10mx20m, using a sampler diameter of 0.05m and depth of 0.1m. The evaluation of the number of seeds and seedling emergence was accomplish at the Laboratory of Seeds Analysis of the Faculdade de Agronomia "Eliseu Maciel" (UFPEL). It was found that both as the crop as the natural seeding allow large quantities of seeds in the soil for the upper area suitable for planting. The harvest area is heterogeneous in the number of seeds in soil and plants in the area. The natural seeding results in a large amount of seed in soil and seedling

Attributes of irrigated rice as affected by soil sodicity and potassic fertilizer application

Soils of the coastal plains of Rio Grande do Sul, Brazil, are affected by salinization, which can hamper the establishment and development of crops in general, including rice. The application of high doses of KCl may aggravate the crop damage, due to the high saline content of this fertilizer. This study aimed to evaluate the effect of K fertilizer management on some properties of rice plant, grown in soils with different sodicity levels, and determine which attribute is best related to yield. The field study was conducted in four Albaqualfs with exchangeable Na percentages of 5.6, 9.0, 21 and 32 %. The management of KCl fertilizer consisted of the application of 90 kg ha-1 K2O broadcast, 90 kg ha-1 K2O in the row and 45 kg ha-1 K2O in the row + 45 kg ha-1 K2O at panicle initiation (PI). Plant density, dry matter evolution, height, SPAD (Soil Plant Analysis Development value indicating relative chlorophyll contents) index, tiller mass, 1,000-grain weight, panicle length and grain yield were evaluated. The plant density was damaged by application of K fertilizer in the row, especially at full dose (90 kg ha-1), at three sodicity levels, resulting in loss in biomass accumulation in later stages, affecting the crop yield, even at the lowest level of soil sodicity (5.6 %). All properties were correlated with yield; the highest positive correlation was found with plant density and shoot dry matter at full flowering, and a negative correlation with panicle length

ACE activity is modulated by kinin B2 receptor

Angiotensin-converting enzyme (ACE) is an ectoprotein able to modulate the activity of a plethora of compounds, among them angiotensin I and bradykinin. Despite several decades of research, new aspects of the mechanism of action of ACE have been elucidated, expanding our understanding of its role not only in cardiovascular regulation but also in different areas. Recent findings have ascribed an important role for ACE/kinin B2 receptor heterodimerization in the pharmacological properties of the receptor. In this work, we tested the hypothesis that this interaction also affects ACE enzymatic activity. ACE catalytic activity was analyzed in Chinese hamster ovary cell monolayers coexpressing the somatic form of the enzyme and the receptor coding region using as substrate the fluorescence resonance energy transfer peptide Abz-FRK(Dnp)P-OH. Results show that the coexpression of the kinin B2 receptor leads to an augmentation in ACE activity. In addition, this effect could be blocked by the B2 receptor antagonist icatibant. The hypothesis was also tested in endothelial cells, a more physiological system, where both proteins are naturally expressed. Endothelial cells from genetically ablated kinin B2 receptor mice showed a decreased ACE activity when compared with wild-type mice cells. In summary, this is the first report showing that the ACE/kinin B2 receptor interaction modulates ACE activity. Taking into account the interplay among ACE, ACE inhibitors, and kinin receptors, we believe that these results will shed new light into the arena of the controversial search for the mechanism controlling these interactions