Exsudação radicular de glyphosate por Brachiaria decumbens e seus efeitos em plantas de eucalipto

Plantas de eucalipto com sintomas de intoxicação por glyphosate são comuns em áreas em que esse herbicida é usado. Uma das possíveis formas de contato com glyphosate é por meio da exsudação radicular do produto, por plantas daninhas tratadas, e subseqüente absorção pelas plantas de eucalipto. Objetivou-se com este trabalho avaliar a exsudação de glyphosate por Brachiaria decumbens e seus efeitos sobre plantas de eucalipto, por meio da aplicação de 14C-glyphosate misturado à calda de pulverização do produto comercial. Mudas de dois clones de eucalipto (UFV05 e UFV06) foram cultivadas em consórcio com Brachiaria decumbens (capim-braquiária), em vasos contendo dois tipos de solo: um arenoso e outro argiloso. Aos 35 dias após o transplantio das mudas, foram aplicados na braquiária 50 µL da mistura de 14C-glyphosate com a formulação comercial de glyphosate Scout®, utilizando-se uma microsseringa de precisão. Aos 2, 8, 16 e 24 dias após aplicação, as plantas de eucalipto foram coletadas e fracionadas em ápice primário, ápices secundários, folhas e raízes, sendo processadas de acordo com metodologia usual para determinação da radioatividade. Não foram observados sintomas de intoxicação por glyphosate nas plantas de eucalipto, em nenhuma das avaliações realizadas. Entretanto, o 14C-glyphosate foi encontrado em todas as plantas de eucalipto avaliadas, independentemente do solo, do clone e da época de avaliação, em maior concentração em plantas cultivadas no solo arenoso. Os resultados evidenciam a exsudação radicular do glyphosate e/ou de seus metabólitos pela braquiária e subseqüente absorção, via raízes, pelas plantas de eucalipto, em concentrações inferiores às necessárias para causar intoxicação na cultura.

Absorção, translocação e exsudação radicular de glyphosate em clones de eucalipto: clones

Objetivou-se com este trabalho avaliar a absorção, translocação e exsudação radicular de glyphosate por dois clones de eucalipto: 2277 e 531. O 14C-glyphosate foi aplicado na concentração de 1.440 g ha-1, distribuída uniformemente no terceiro e no quarto limbo foliar a partir do ápice caulinar, com radioatividade aproximada de 0,030 μCi. A absorção, translocação e exsudação radicular foram avaliadas pela radioatividade do 14C-glyphosate nos diferentes tecidos da planta, bem como na água de lavagem e solução nutritiva, nos intervalos de 0, 2, 8, 32 e 72 horas após a aplicação - HAA. A concentração de 14C-glyphosate na folha aplicada foi semelhante para os dois clones nas avaliações a partir de 8 HAA. Todavia, considerando a planta inteira, ela foi superior no clone 2277 em todas as épocas de avaliação. Maior quantidade de 14C-glyphosate foi verificada na água de lavagem da folha aplicada do clone 531, indicando menor absorção do herbicida nesse clone em relação ao 2277. Na parte aérea e no sistema radicular, a concentração do 14C-glyphosate foi semelhante entre os clones em todos os intervalos de avaliação, porém com concentrações maiores nas raízes. Pequena parte do total aplicado foi exsudada para solução nutritiva (valores entre 0,78 e 1,16%), não havendo diferença entre os clones quanto à translocação na planta e na exsudação radicular do herbicida. A absorção diferencial entre os clones, atribuída na maioria dos casos a diferenças na estrutura e composição da cutícula, pode ser uma possível explicação para a tolerância diferencial entre os genótipos.

Eficiência fotossintética e uso da água em plantas de eucalipto pulverizadas com glyphosate

Objetivou-se com este trabalho avaliar a eficiência fotossintética e o uso da água por plantas de clones de eucalipto submetidas ao herbicida glyphosate. O experimento foi realizado em esquema fatorial 4 x 5, com quatro clones de eucalipto (57, 386, 1203 e 1213) e quatro doses de glyphosate (43,2; 86,2; 129,6; e 172,8 g ha-1) e uma testemunha sem herbicida, considerada dose zero, com quatro repetições. Aos 7, 14, 21 e 28 dias após aplicação do herbicida (DAA) foi avaliada a intoxicação das plantas, e aos 7 e 21 DAA, o fluxo de gases pelos estômatos (U - mmol s-1), a atividade fotossintética (A - mmol m-2 s-1), a condutância estomática (Gs - mol m-1 s-1), a transpiração (E - mol H2O m-2 s-1) e a eficiência do uso da água (QUE - mol CO2 mol H2O-1). Aos 50 DAA, as plantas de eucalipto foram coletadas e colocadas em estufa de ventilação forçada a 70 ºC até atingirem massa constante. Aos 21 DAA, o clone 1203 comportou-se como mais sensível ao herbicida. Não houve diferença entre clones para as variáveis fisiológicas avaliadas. Aos 21 DAA constatou-se que, com o incremento da dose de glyphosate, houve redução na condutância estomática, na taxa de fluxo de gases pelos estômatos, na taxa fotossintética e na eficiência do uso da água. Plantas dos clones 1213 e 1203 apresentaram maior acúmulo de massa seca. O aumento da dose do glyphosate promoveu menor acúmulo de massa seca das plantas de eucalipto. O glyphosate afetou negativamente o crescimento e a eficiência fotossintética e de uso da água dos clones estudados.

Quantificação e composição química de cera epicuticular de folhas de eucalipto

Objetivou-se neste trabalho quantificar e relatar a composição química da cera epicuticular da folha de seis clones de eucalipto (UFV01, UFV02, UFV03, UFV04, UFV05 e UFV06). A cera epicuticular foi extraída e quantificada, e os seus constituintes, analisados por cromatografia a gás acoplada a espectrômetro de massas. Maior quantidade de cera por área foliar foi encontrada nos clones UFV01, UFV02 e UFV05, enquanto o clone UFV03 apresentou o menor teor de cera. Nas amostras submetidas à espectrometria de massas, foram identificados 31 constituintes nos seis clones de eucalipto avaliados. A análise das amostras revelou maior presença de hidrocarbonetos entre os compostos identificados na folha. O componente encontrado em maior proporção nos clones UFV02 (36,07%), UFV03 (33,00%) e UFV06 (40,98%) foi o 3β-acetoxi-urs-12-en-28-al, ao passo que nos clones UFV01 (17,80%), UFV04 (11,38%) e UFV05 (17,62%) a maior proporção foi do hexacosano. Os clones UFV02 e UFV04 apresentaram, em sua cera, maior variedade de componentes químicos (19 componentes) do que os demais genótipos avaliados, havendo variação quanto ao tipo e à quantidade de compostos entre os genótipos, mesmo em clones pertencentes à mesma espécie.

Seletividade e absorção radicular do sulfentrazone em clones de eucalipto

O objetivo deste trabalho foi avaliar a seletividade e a absorção do sulfentrazone em clones de eucalipto. O primeiro experimento foi instalado em casa de vegetação, em delineamento inteiramente casualizado, com quatro repetições, no esquema fatorial 2 x 4, sendo duas doses do sulfentrazone (400 e 600 g ha-1) e quatro clones de eucalipto, híbridos de Eucalyptus grandis x E. urophylla (FB1, FB2, FB3 e FB4). Foram realizadas avaliações visuais de intoxicação das plantas de eucalipto e, no final do estudo, determinou-se a massa seca da parte aérea dos clones. No segundo experimento, foram utilizados os mesmos clones, sendo estes acondicionados em tubos falcon com 50 mL da solução contendo o sulfentrazone na concentração de 129 mM. As plantas de eucalipto permaneceram por 24 horas com as raízes imersas na solução e, em seguida, foi realizada a extração da seiva do xilema das plantas por meio de uma câmara de pressão. A concentração de sulfentrazone na seiva das plantas foi determinada através de cromatografia líquida e espectrometria de massas. O clone FB3 apresentou menor acúmulo de massa seca em relação aos demais, o que pode estar diretamente associado aos altos níveis de intoxicação observados. O clone FB2, apesar de mostrar elevada intoxicação, não apresentou níveis tão elevados de redução de massa seca em relação à testemunha. No tocante às concentrações de sulfentrazone nas plantas, elas foram proporcionais ao acúmulo de massa seca, o que indica que as variações na seletividade dos clones de eucalipto podem estar relacionadas à absorção diferenciada do herbicida.

Eucalyptus growth in silvopastoral system under different crown dia meters

The aim of this study was to evaluate the effect of different crown diameters on the early growth of eucalyptus intercropped with Brachiaria decumbens in a silvopastoral system. The experiment was conducted in a B. decumbens established pasture, where hybrid eucalyptus urograndis (clone GG100) was planted, spaced 8 x 3 m. A randomized block design was used, with six replicates. Treatments consisted of five crown diameters (0.0, 1.0, 1.5, 2.0, and 3.0 m) surrounding the eucalyptus plants. Five weeding hoes were performed throughout the experiment, according to the different crown diameters, aiming to maintain the eucalyptus plants free from B. decumbens interference. At 90, 180, 270, and 360 DAP, the height and the diameter of the eucalyptus plants were evaluated, and at 360 DAP, surface biomass and leaf area were evaluated. At 90 DAP, it was verified that the non-weeded plants had lower growth, compared to those submitted to crowns. Crown diameters of 2.51 and 2.64 m allowed greater growth in height and diameter at ground level of eucalyptus plants, respectively, in all periods evaluated. Biomass production and leaf area per plant at 360 DAP were also influenced by the different crown diameters. It was concluded that crown diameter around 2 meters provided favorable conditions for early growth of eucalyptus and less involvement in the area occupied by forage.

Grass Weeds Interfering with Eucalypt: Effects of the Distance of Coexistence on the Initial Plant Growth

Two experiments were carried out to evaluate the initial plant growth of Eucalyptus urograndis growing in coexistence with Urochloa decumbens and U. ruziziensis. In 100-L box, one plant of U. decumbens or U. ruziziensis grew in coexistence with one plant of E. urograndis clones C219H or H15, respectively, in the distances of 0, 5, 10, 15, 20, 25, 30, 35, and 40 cm from the crop. After 30, 60, 90 (both clones), and 150 days (just for H15), growth characteristics were evaluated. Plants of both clones, growing in weed-free situations, showed a better growth and development than plants that grew in weedy situations, independently of the distance, having the highest plant height, stem diameter, dry mass of stem, and dry mass of leaves. As the same way, the number of branches, number of leaves, and leaf area of the clone C219H were similarly affected. Urochloa ruziziensis reduced the dry mass accumulation of stem and leaves by the rate of 0.06 and 0.32 g per plant, respectively, per each centimeter growing nearest to the crop, while U. decumbens reduced by 0.03 and 0.14 g per plant. The interference of U. decumbens and U. ruziziensis with E. urograndis is more intense when weedy plants grow in short distances from the crop.

Advanced Islandora Workshop

Workshop at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

A 37-kb restriction map of the human immunoglobulin lambda variable locus, VB cluster, harboring four functional genes and two non-coding Vl sequences

The human immunoglobulin lambda variable locus (IGLV) is mapped at chromosome 22 band q11.1-q11.2. The 30 functional germline v-lambda genes sequenced untill now have been subgrouped into 10 families (Vl1 to Vl10). The number of Vl genes has been estimated at approximately 70. This locus is formed by three gene clusters (VA, VB and VC) that encompass the variable coding genes (V) responsible for the synthesis of lambda-type Ig light chains, and the Jl-Cl cluster with the joining segments and the constant genes. Recently the entire variable lambda gene locus was mapped by contig methodology and its one- megabase DNA totally sequenced. All the known functional V-lambda genes and pseudogenes were located. We screened a human genomic DNA cosmid library and isolated a clone with an insert of 37 kb (cosmid 8.3) encompassing four functional genes (IGLV7S1, IGLV1S1, IGLV1S2 and IGLV5a), a pseudogene (VlA) and a vestigial sequence (vg1) to study in detail the positions of the restriction sites surrounding the Vl genes. We generated a high resolution restriction map, locating 31 restriction sites in 37 kb of the VB cluster, a region rich in functional Vl genes. This mapping information opens the perspective for further RFLP studies and sequencing

The yellow fever 17D vaccine virus: molecular basis of viral attenuation and its use as an expression vector

The yellow fever (YF) virus is the prototype flavivirus. The use of molecular techniques has unraveled the basic mechanisms of viral genome structure and expression. Recent trends in flavivirus research include the use of infectious clone technology with which it is possible to recover virus from cloned cDNA. Using this technique, mutations can be introduced at any point of the viral genome and their resulting effect on virus phenotype can be assessed. This approach has opened new possibilities to study several biological viral features with special emphasis on the issue of virulence/attenuation of the YF virus. The feasibility of using YF virus 17D vaccine strain, for which infectious cDNA is available, as a vector for the expression of heterologous antigens is reviewed

Increased fetal hemoglobin levels in patients infected with human immunodeficiency virus (HIV1/2)

Fetal hemoglobin was measured in HIV1/2 patients under treatment with combined therapy (zidovudine and a protease inhibitor). A total of 143 patients and 103 normal individuals were investigated by the quantitative method of Betke and the semi-quantitative acid elution method of Kleihauer. In the normal person, hemoglobin F makes up less than 1% and an increase higher than 1.5% was observed in 21.4% of HIV patients by the method of Betke and in 24.8% of HIV-infected patients by the method of Kleihauer. The quantitative biochemical method of Betke showed that the populations were significantly different (two-tailed Mann-Whitney test). The reason for this hemoglobin F increase might be ascribed to the effect of zidovudine or to direct viral action on gamma chain expression. The finding of a higher F cell frequency indicated by the method of Kleihauer rather suggests that there is an increased F cell clone proliferation rather than an increase in hemoglobin F level in every cell.

Acute promyelocytic leukemia: the study of t(15;17) translocation by fluorescent in situ hybridization, reverse transcriptase-polymerase chain reaction and cytogenetic techniques

Acute promyelocytic leukemia (AML M3) is a well-defined subtype of leukemia with specific and peculiar characteristics. Immediate identification of t(15;17) or the PML/RARA gene rearrangement is fundamental for treatment. The objective of the present study was to compare fluorescent in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR) and karyotyping in 18 samples (12 at diagnosis and 6 after treatment) from 13 AML M3 patients. Bone marrow samples were submitted to karyotype G-banding, FISH and RT-PCR. At diagnosis, cytogenetics was successful in 10 of 12 samples, 8 with t(15;17) and 2 without. FISH was positive in 11/12 cases (one had no cells for analysis) and positivity varied from 25 to 93% (mean: 56%). RT-PCR was done in 6/12 cases and all were positive. Four of 8 patients with t(15;17) presented positive RT-PCR as well as 2 without metaphases. The lack of RT-PCR results in the other samples was due to poor quality RNA. When the three tests were compared at diagnosis, karyotyping presented the translocation in 80% of the tested samples while FISH and RT-PCR showed the PML/RARA rearrangement in 100% of them. Of 6 samples evaluated after treatment, 3 showed a normal karyotype, 1 persistence of an abnormal clone and 2 no metaphases. FISH was negative in 4 samples studied and 2 had no material for analysis. RT-PCR was positive in 4 (2 of which showed negative FISH, indicating residual disease) and negative in 2. When the three tests were compared after treatment, they showed concordance in 2 of 6 samples or, when there were not enough cells for all tests, concordance between karyotype and RT-PCR in one. At remission, RT-PCR was the most sensitive test in detecting residual disease, as expected (positive in 4/6 samples). An incidence of about 40% of 5' breaks and 60% of 3' breaks, i.e., bcr3 and bcr1/bcr2, respectively, was observed.

A tobacco cDNA reveals two different transcription patterns in vegetative and reproductive organs

In order to identify genes expressed in the pistil that may have a role in the reproduction process, we have established an expressed sequence tags project to randomly sequence clones from a Nicotiana tabacum stigma/style cDNA library. A cDNA clone (MTL-8) showing high sequence similarity to genes encoding glycine-rich RNA-binding proteins was chosen for further characterization. Based on the extensive identity of MTL-8 to the RGP-1a sequence of N. sylvestris, a primer was defined to extend the 5' sequence of MTL-8 by RT-PCR from stigma/style RNAs. The amplification product was sequenced and it was confirmed that MTL-8 corresponds to an mRNA encoding a glycine-rich RNA-binding protein. Two transcripts of different sizes and expression patterns were identified when the MTL-8 cDNA insert was used as a probe in RNA blots. The largest is 1,100 nucleotides (nt) long and markedly predominant in ovaries. The smaller transcript, with 600 nt, is ubiquitous to the vegetative and reproductive organs analyzed (roots, stems, leaves, sepals, petals, stamens, stigmas/styles and ovaries). Plants submitted to stress (wounding, virus infection and ethylene treatment) presented an increased level of the 600-nt transcript in leaves, especially after tobacco necrosis virus infection. In contrast, the level of the 1,100-nt transcript seems to be unaffected by the stress conditions tested. Results of Southern blot experiments have suggested that MTL-8 is present in one or two copies in the tobacco genome. Our results suggest that the shorter transcript is related to stress while the larger one is a flower predominant and nonstress-inducible messenger.

Cissampelos sympodialis Eichl (Menispermaceae) leaf extract induces interleukin-10-dependent inhibition of Trypanosoma cruzi killing by macrophages

The aqueous fraction of the ethanolic extract (AFL) of Cissampelos sympodialis Eichl (Menispermaceae), popularly known as milona, has been shown to have both immunosuppressive and anti-inflammatory effects. In the present study we investigated the modulation of macrophage antimicrobicidal activity by in vitro treatment with the extract from C. sympodialis. Normal and thioglycolate-elicited mouse peritoneal macrophages were infected in vitro with the protozoan Trypanosoma cruzi DM28c clone. We observed that the AFL (used at doses ranging from 13 to 100 µg/ml) increased T. cruzi growth and induced a 75% reduction in nitric oxide production. This inhibition could be mediated by the stimulation of macrophage interleukin-10 (IL-10) secretion since the in vitro treatment with the AFL stimulated IL-10 production by T. cruzi-infected macrophages. These results suggest that the anti-inflammatory effect of the AFL from C. sympodialis could be, at least in part, mediated by the inhibition of macrophage functions and that the inhibition of macrophage microbicidal activity induced by the C. sympodialis extract may be mediated by the decrease in macrophage function mediated by interleukin-10 production.

IS1245 restriction fragment length polymorphism typing of Mycobacterium avium from patients admitted to a reference hospital in Campinas, Brazil

Mycobacterium avium is an important pathogen among immunodeficient patients, especially patients with AIDS. The natural history of this disease is unclear. Several environmental sources have been implicated as the origin of this infection. Polyclonal infection with this species is observed, challenging the understanding of its pathogenesis and treatment. In the present study 45 M. avium strains were recovered from 39 patients admitted to a reference hospital between 1996 and 1998. Species identification was performed using a species-specific nucleic acid hybridization test (AccuProbe®) from Gen-Probe®. Strains were genotyped using IS1245 restriction fragment length polymorphism typing. Blood was the main source of the organism. In one patient with disseminated disease, M. avium could be recovered more than once from potentially sterile sites. Strains isolated from this patient had different genotypes, indicating that the infection was polyclonal. Four patient clones were characterized in this population, the largest clone being detected in eight patients. This finding points to a common-source transmission of the organism.