Estudos sobre a nutrição mineral do arroz: XXI - efeito das deficiências e excessos minerais na atividade da redútase de nitrato foliar e no teor de proteina dos grãos (nota prévia)

Rice plants, varieties IAC-164 and IAC-165 weree grown in number 2 Hoagland's solution, full strength, and with excess of Al and Cl. Nitrate reductase (RNO3) activity was assayed in the leaves one month before harvesting. When the grains were already dry, plants were harvested, the mineral contents of the organs was determined, and crude protein in the grains was also determined (semi micro Kjeldahl). Statistical analyses of the data thus obtained showed that enzymatic activity decreased when the plants were deficient in N, P, and K, as well as when the plants were deficient in N, P, and K, as well as when they had excess Al and Cl. Sulfur deficiency depressed RNO3 activity in variety IAC-164 only. Lack of Mg had the same effect in variety IAC-165. Crude protein in the grains decreased due to lack of N, P, Cu, and S, and to excess both of Al and Cl. In both varieties, however, the deficiencies of K and Mg had apparently the opposite effect. By putting together data from all treatments (except -K and -Mg) a positive correlation between leaf RNO3 activity and grain protein was found to exist.Plantas de arroz das variedades IAC-164 e IAC-165 foram cultivadas em solução nutritiva (nº 2 de Hoagland), completa com deficiência de macronutrientes e de B, Cu e Zn e com excesso de Al e Cl. No fim do ciclo, foi determinada a atividade da redútase de nitrato (RNO3) nas folhas, e após a maturação, foi determinado o teor de proteína bruta dos grãos. Nas duas variedades verificou-se que a atividade enzimática foi diminuída pelas deficiências de N, P, K e pela toxidez de Al e Cl; na IAC-164 a carência de S teve o mesmo efeito depressivo; na IAC-I65, além do efeito mencionado, houve o da falta de Mg. O teor de proteína bruta nos grãos diminuiu com as deficiências de N, P, Se Cu e com a toxidez de Al; aumentou aparentemente nos tratamentos com deficiência de K e Mg. Foi encontrada correlação entre atividade de RNO3 e teor proteico dos grãos quando os dados relativos aos tratamentos -K e -Mg não foram considerados

Estudos sobre a nutrição mineral do arroz: XIX - marcha de absorção de macronutrientes pelas variedades IAC-164 e IAC-165

Dry matter production and accumulation of macronutrients were studied by growing plants in nutrient solution and taking samples at given physiological intervals. It was found that curves describing dry matter production and uptake were sigmoidal in tendency. Maximum rate of uptake was observed within a 2-month period starting at full tillering and ending at the stage of panicle formation. Leaf levels of N, P, and K decrease as the plant grows older; the opposite is true in the case of the other elements.Foi estudada à marcha de absorção de macronutrientes nas variedades de arroz IAC-164 e IAC-164 cultivadas em solução nutritiva, chegando-se às seguintes conclusões: as curvas que descrevem a acumulação de matéria seca e de nutrientes apresentam tendência sigmoide; o período de maior absorção vai do perfilhamento pleno à formação da panícula (2 meses aproximadamente); os teores foliares de H, P e K apresentaram tendência para diminuir do começo para o fim do ciclo o inverno ocorrendo com os dos outros elementos

Prevalence and risk factors for bovine leptospirosis in Mato Grosso do Sul, Brazil

Foi investigada a prevalência de anticorpos antileptospira em fêmeas bovinas com idade igual ou superior a 24 meses, provenientes de 178 rebanhos de 22 municípios do estado de Mato Grosso do Sul, bem como identificados fatores de risco associados à infecção. Foram analisadas 2.573 amostras de soro sangüíneo por meio do teste de soroaglutinação microscópica perante 10 sorovares de leptospira. Títulos iguais ou superiores a 100 para um ou mais sorovares foram detectados em 1.801 fêmeas (98,8%) de 161 (96,5%) rebanhos. O sorovar Hardjo (65,6%) foi apontado como o mais provável, seguido do sorovar Wolffi (12,3%). Os resultados demonstram que a leptospirose bovina se encontra presente em todos os municípios estudados, com alta prevalência, tanto em animais como em rebanhos. Os fatores de risco identificados neste estudo e associados à infecção por bactérias do gênero lepstopira foram o tipo de exploração pecuária de corte e a raça Zebu. _____________________________________________________________________________________________________________ ABSTRACTThe prevalence of anti-Leptospira spp. antibodies was estimated for female cattle aged 24 months or older. The sample comprised 178 herds from 22 counties in the state of Mato Grosso do Sul, Brazil. The risk factors associated with the presence of infeccion were investigated. A total of 2,573 blood serum samples were tested against 10 leptospira serovars using the microagglutination test (MAT). Titers of 100 or higher for one or more serovars were detected in 1,801 females (98.8%) from 161 herds (96.5%). Serovar Hardjo (65.6%) was the most frequent, followed by serovar Wolffi (12.3%). These results suggest that bovine leptospirosis is widespread in all the counties under study, with a high prevalence both at the animal and the herd level. Beef farms and the Zebu breed were associated to the higher risk of herd infection by leptospiras

Human toxocariasis: contribution by Brazilian researchers

In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT)

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset