In vitro and in vivo antimalarial activity and cytotoxicity of extracts, fractions and a substance isolated from the Amazonian plant Tachia grandiflora (Gentianaceae)

Tachia sp. are used as antimalarials in the Amazon Region and in vivo antimalarial activity of a Tachia sp. has been previously reported. Tachia grandiflora Maguire and Weaver is an Amazonian antimalarial plant and herein its cytotoxicity and antimalarial activity were investigated. Spectral analysis of the tetraoxygenated xanthone decussatin and the iridoid aglyone amplexine isolated, respectively, from the chloroform fractions of root methanol and leaf ethanol extracts was performed. In vitro inhibition of the growth of Plasmodium falciparum Welch was evaluated using optical microscopy on blood smears. Crude extracts of leaves and roots were inactive in vitro. However, chloroform fractions of the root and leaf extracts [half-maximal inhibitory concentration (IC50) = 10.5 and 35.8 µg/mL, respectively] and amplexine (IC50= 7.1 µg/mL) were active in vitro. Extracts and fractions were not toxic to type MRC-5 human fibroblasts (IC50> 50 µg/mL). Water extracts of the roots of T. grandiflora administered by mouth were the most active extracts in the Peters 4-day suppression test in Plasmodium berghei-infected mice. At 500 mg/kg/day, these extracts exhibited 45-59% inhibition five to seven days after infection. T. grandiflora infusions, fractions and isolated substance have potential as antimalarials.

Utilização de bioensaios e marcadores moleculares para detecção da resistência de coleópteros de produtos armazenados a inseticidas

The qualitative and quantitative losses caused by stored product insects are of great concern, and since there is only a few active ingredients available for their control it is very important to have a frequent insect resistance monitoring. The objective of this research is to evaluate combination of bioassays and molecular marker techniques to detect insecticide resistance in stored product beetles. The Coleoptera species used for the tests were Sitophilus oryzae (L.) (Curculionidae), Rhyzopertha dominica (F.) (Bostrichidae) and Oryzaephilus surinamensis (L.) (Silvanidae). For the bioassays it was used the impregnated filter paper technique, applying 1 mL of deltamethrin (K-Obiol 25 CE TM) using four concentrations and five replicates, including a control with solvent only. Ten adults of each species were liberated separately on each dish. The mortality was evaluated after 24 h and resistance determined by probit analysis. The samples used for the PCR-RAPD were either in vivo or preserved in 70% ethanol, kept in -18°C freezer. After extraction, quantification and DNA quality analysis, the 25 µL samples had the DNA amplified and tested with six primers. The bioassays showed a crescent mortality proportional to insecticide concentration. The resistance factor for R. dominica, S. zeamais and S. oryzae were: 2,2; 3,2 and 9,2, respectively, compared to the susceptible populations of each species. The PCR-RAPD analysis revealed bands which indicate inter and intraspecific variability in the populations, but it was not possible to correlate them to resistance. The association of bioassay and PCR-RAPD represents a precise and valuable tool for resistance management of stored product insects, but more populations and primers should be tested.

Intra-puparial development of the females of Chrysomya albiceps (Wiedemann) (Diptera, Calliphoridae)

Intra-puparial development of the females of Chrysomya albiceps (Wiedemann) (Diptera, Calliphoridae). The chronology and morphological changes that take place during intra-puparial development of Chrysomya albiceps is described based on 254 specimens reared in the laboratory. Larvae were obtained from the eggs laid by a single female. The pre-pupae were separated according to the reduction of larval length and the degree of pigmentation and sclerotization of the cuticle. After pupation, 10 individuals were fixed in Carnoy's solution and preserved in 70% ethanol, 10 individuals were fixed every 3 hours up to complete the first 24 hours (n = 80), the remaining individuals were fixed every six hours up to the 90th hour (n = 110) when 54 females emerged. The pupae were immersed in 5% formic acid for 48 hours and maintained in 70% ethanol, and then dissected and analyzed. C. albiceps shows four intra-puparial stages, each of which were described and compared with those described for Musca domestica, Calliphora erythrocephala, Sarcophaga bullata, Cuterebra tenebrosa, Oestrus ovis and Dermatobia hominis. Four developmental stages may be described: (1) the larva-pupa apolysis, after three hours; (2) the criptocephalic pupa, after six hours; (3) the phanerocephalic pupa, after nine hours; (4) the pharate pupa, after nine hours. The pharate adult is completely formed after 81 hours.

Sugarcane trash management assessed by the interaction of yield with soil properties

Currently, sugarcane plays an important global role, particularly with a view to alternative energy sources. Thus, in a sugarcane field of the mill Vale do Paraná S/A Álcool e Açúcar, Rubineia, São Paulo State, managed under two green cane harvest systems (cane trash left on and cane trash removed from the soil), Pearson and spatial correlations between the sugarcane yield (variety RB855035 in the third cut) and soil physical and chemical properties were studied to identify the property best correlated with stalk yield and the best harvest method. For this purpose, two geostatistical grids (121 sampling points on 1.30 ha) were installed on a eutrophic Red Argisol (homogeneous slope of 0.065 m m-1), in 2011, to determine the properties: stalk yield and sugarcane plant population, and soil resistance to penetration, gravimetric moisture, bulk density, and carbon stock, in the layers 0-0.20 and 0.20-0.40 m. The data were analyzed by descriptive, linear correlation and geostatistical analysis. In both treatments, the property stand density was best correlated with sugarcane yield (r = 0.725 in the trash mulching treatment - TM and r = 0.769 in the trash removal treatment - TR). However, in relation to the soil properties, bulk density (0-0.20 m) was best correlated (r = 0.305 in TM, r = 0.211 in TR). Similarly, from the spatial point of view, stand density was the property that best explained the sugarcane yield. However, in the TM treatment the density (0.20-0.40 m) was the only soil property spatially correlated with stalk yield. The carbon stock in the soil of the TM was 11.5 % higher than in the TR treatment. Results of the TM treatment were best, also with regard to soil management and conservation.

SWEET SORGHUM PERFORMANCE AFFECTED BY SOIL COMPACTION AND SOWING TIME AS A SECOND CROP IN THE BRAZILIAN CERRADO

ABSTRACT Increasing attention has recently been given to sweet sorghum as a renewable raw material for ethanol production, mainly because its cultivation can be fully mechanized. However, the intensive use of agricultural machinery causes soil structural degradation, especially when performed under inadequate conditions of soil moisture. The aims of this study were to evaluate the physical quality of aLatossolo Vermelho Distroférrico (Oxisol) under compaction and its components on sweet sorghum yield forsecond cropsowing in the Brazilian Cerrado (Brazilian tropical savanna). The experiment was conducted in a randomized block design, in a split plot arrangement, with four replications. Five levels of soil compaction were tested from the passing of a tractor at the following traffic intensities: 0 (absence of additional compaction), 1, 2, 7, and 15 passes over the same spot. The subplots consisted of three different sowing times of sweet sorghum during the off-season of 2013 (20/01, 17/02, and 16/03). Soil physical quality was measured through the least limiting water range (LLWR) and soil water limitation; crop yield and technological parameters were also measured. Monitoring of soil water contents indicated a reduction in the frequency of water content in the soil within the limits of the LLWR (Fwithin) as agricultural traffic increased (T0 = T1 = T2>T7>T15), and crop yield is directly associated with soil water content. The crop sown in January had higher industrial quality; however, there was stalk yield reduction when bulk density was greater than 1.26 Mg m-3, with a maximum yield of 50 Mg ha-1 in this sowing time. Cultivation of sweet sorghum as a second crop is a promising alternative, but care should be taken in cultivation under conditions of pronounced climatic risks, due to low stalk yield.