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In the Orinoco lowlands, savannas have been often replaced by pastures composed of the C grass, Brachiaria decumbens Stapf. We addressed following questions: ( 1) How does the replacement of the native vegetation affect CO exchange on seasonal and annual scales? ( 2) How do biophysical constraints change when the landscape is transformed? To assess how these changes affect carbon exchange, we determined simultaneously the CO fluxes by eddy covariance, and the soil CO efflux by a chamber-based system in B. decumbens and herbaceous savanna stands. Measurements covered a one-year period from the beginning of the dry season (November 2008) to the end of the wet season (November 2009). During the wet season, the net ecosystem CO exchange reached maximum values of 23 and 10 μmol(CO) m s in the B. decumbens field and in the herbaceous savanna stand, respectively. The soil CO efflux for both stands followed a temperature variation during the dry and wet seasons, when the soil water content (SWC) increased above 0.087 m m in the latter case. Bursts of CO emissions were evident when the dry soil experienced rehydration. The carbon source/sink dynamics over the two canopies differed markedly. Annual measurements of the net ecosystem production indicated that the B. decumbens field constituted a strong carbon sink of 216 g(C) m y. By contrast, the herbaceous savanna stand was found to be only a weak sink [36 g(C) m y]. About 53% of the gross primary production was lost as the ecosystem respiration. Carbon uptake was limited by SWC in the herbaceous savanna stand as evident from the pattern of water-use efficiency (WUE). At the B. decumbens stand, WUE was relatively insensitive to SWC. Although these results were specific to the studied site, the effect of land use changes and the physiological response of the studied stands might be applicable to other savannas. [ABSTRACT FROM AUTHOR]

This research was carried out in the Puracé municipality, Cauca, Colombia. Its target was to evaluate the insecticide effect of the Bocconia frutescensextract on the white grubs of Ancognatha vulgaris. A randomnized block design with five treatments and three replicates was applied. The treatments T1, T2 and T3 corresponding to 14, 17 and 20% concentrations of the plant extract, T4 to a commercial product (Carbofuran) and T5 as an absolute control. The variables evaluated were the presence of healthy and affected larvae; and the damage percentage on plants evaluated as incidence and severity Significative differences were found for the % intensity, %infestation, healthy and affected larvae variables, at different evaluated times. The best insecticide effect treatment was T2 (17% plant extract) followed by T3 and T1. For the plant damage variables, the higher percentage treatments were T2 and T5 with 57% intensity and 55% and 45% infestation for T2 and T3 respectively. The presence of alkaloids, terpenes, anthrones and coumarines in the plant extract was demonstrated by phytochemical analysis. The effect of the B. frutescensextract on white grubs was dehydration and flaccidity provoking death at any of the concentrations assayed. This was attributed to the action of single metabolites or their combination. [ABSTRACT FROM AUTHOR]

Background/objectives:Fatty-acid status during in-utero development might influence the risk of atopic diseases in early childhood. The aim of this work was to identify the relationship between maternal plasma and cord blood fatty acid (FA) composition and the risk of atopic eczema in the offspring at 14 months of age.Subjects/methods:Two hundred and eleven non-atopic mothers and their children were studied. Mothers were recruited in their first trimester of gestation and children were monitored until 14 months of age. Samples of maternal plasma and cord blood plasma were analyzed to determine the FA profile of total lipids. Presence of atopic eczema in the infants was documented through questionnaires at 6 and 14 months of age.Results:Higher concentrations of total long-chain polyunsaturated FA (LC-PUFA) were found in maternal plasma of non-atopic children in relation to atopic group. Moreover, this maternal plasma LC-PUFA content was negatively correlated with the atopic eczema (odds ratios (OR)=0.83, P=0.04) in infants. Regarding cord blood samples, docosahexaenoic acid (DHA C22:6n3) and the sum of total n-3 and of LC-PUFA n-3 showed a negative correlation with the prevalence of the disease (OR=0.50, 0.49 and 0.49, respectively).Conclusions:Our results show that the fatty-acid status of the fetus during pregnancy has an important role in the development of atopic eczema in early childhood. The prevalence of this atopic disorder is related to lower cord blood plasma levels of FA belonging to n-3 series, especially DHA. [ABSTRACT FROM AUTHOR]

The trial was aimed at evaluating anthracnose (Colletotrichum lindemuthianum), in bean cultivars (Phaseolus vulgaris) in a rural area of Timbío, located in the Cauca Department of Colombia, applying a randomized complete block (RCB) design with 2 treatments and 3 repetitions. Two bean varieties were evaluated: Diacol Calima and AFR 612, under two agricultural management systems: Traditional Management (T), in which the protocol used by farmers in the area with frequent applications of fungicides to control disease was followed, and Integrated Management (IPM) . The incidence and severity variables in leaves flowers and pods at stages V2, V4, R6, R7 and R8 of the crop and number of pods / plant, production of pods / plot, grain / plot (g) yield, weight of 100 seeds (g) and percentage of germination were assessed.The results indicated that under Traditional Management the Diacol Calima variety showed the highest rates of incidence of anthracnose in stages V2, V4 and R6 in leaves and R8 in pods. The AFR 612 variety evaluated under Integrated Management, presented the lowest percentages of anthracnose's incidence and the highest production yields. [ABSTRACT FROM AUTHOR]

There is barely any information about the prognostic significance of FLT3 expression and mutational status in cytogenetically distinct subgroups of acute lymphoblastic leukemia (ALL). We analyzed the presence of FLT3-tyrosine kinase domain (TKD) and FLT3-internal tandem duplication (ITD) mutations as well as FLT3 expression levels in 54 newly diagnosed patients with B-ALL (n=49) or T-ALL (n=5). All B/T-ALL samples tested negative for the presence of FLT3-TKD or FLT3-ITD. None of the T-ALL and E2A-PBX1+ B-ALL overexpressed FLT3. In contrast, mainly MLL-AF4+ B-ALL but also ETV6-RUNX1+, BCR-ABL+ or B-ALL displaying normal cytogenetics exhibited significantly higher FLT3 expression levels than normal bone marrow, supporting that aberrantly increased transcription of FLT3, rather than activating FLT3 mutations, contributes to the pathogenesis of these B-ALL. Using the median FLT3 expression as cut-off value we found that high-level FLT3 expression is associated with an extremely poor 1-year overall survival (OS; 0 vs 71%; P=0.002) and disease-free survival (DFS; 0 vs 43%; P=0.03) in MLL-AF4+ B-ALL but not in MLL-germline B-ALL. Cox regression analysis with OS/DFS as end points showed that age>14 years and high-level FLT3 expression were independent prognostic factors when all ALL patients were analyzed together. Importantly, when the MLL-AF4+ B-ALL subgroup was analyzed separately, high-level FLT3 expression was the only independent prognostic factor for OS and treatment outcome. These findings indicate that high FLT3 expression identifies MLL-AF4+ ALL patients at very high risk of treatment failure and poor survival, emphasizing the value of ongoing/future clinical trials for FLT3 inhibitors. [ABSTRACT FROM AUTHOR]

The epidemiological study was carried out on three Colombian coffee production limiting pests, i.e. Coffee borer (Hypothenemus hampei Ferrari), Coffee rust (Hemileia vastatrix) and Iron spot disease (Cercospora coffeicola) of four municipalities of the Cauca department. Eight sensoring localities were selected and sampled monthly in order to obtain the infestation and incidence of each pest during 2006 and 2007(from March and December). Sampling was done according to the process established by Cenicafé, 30 Coffee shrubs were taken for the Coffee borer and the Iron spot disease evaluation, and 10 for coffee rust evaluation per hectare respectively, the corresponding infestation and incidence percentages were obtained by grain and leaves counting. Temperature, precipitation, relative humidity and solar bright data were obtained from neighboring climatological stations, in order to relate the pests behavior with climate. The plagues infestation and incidence in most cases exceeded the 5% economical damage threshold; the mean incidence and infestation during the evaluation period was 14,7% for Rust, 4,7% for Coffee borer and 4,8% on Iron spot disease. The temperature and precipitation variables were the ones which exhibited closer relationship with the plagues epidemiological dynamics. High temperatures are related to high Coffee borer and Rust incidence, mainly between June and September, contrary to the Iron spot disease, which was related to high precipitations, mainly between March and May. The results give en alert concerning plagues presence on the regional crops. [ABSTRACT FROM AUTHOR]

The research target was to value Sechium edule as a nutrition alternative for displaced families living in Popayan's marginal urban settlements, aiming to contribute to the traditional knowledge recuperation associated it's use and management, to identify the sociocultural significance as an alternative to mantain the links with the country, to evaluate the productivity and management possibilities in urban marginal areas. The process was carried out by means of "participative investigation" where actors participated on recreative dynamics, sensibilization and socialization workshops, knowledge generating and exchanging tours which also served for exchanging seeds, permitting to obtain information and empowerment with the process. Three communities of Popayan were defined as study areas, four settlements were selected and 116 interviews made. The settlements were visited monthly for informal dialogues with the participating families. The plant's management possibilities were studied and it's cultivation under an urban cultivation scheme in association with other orchard species incentivated. The adptation of the system under the settlement's condition was asessed as a an alimentary alternative for these population. The consumption of sub-utilized species and the ecotype's conservation were encouraged. [ABSTRACT FROM AUTHOR]

Infant acute lymphoblastic leukemia (ALL) involving mixed-lineage leukemia (MLL) fusions has attracted a huge interest in basic and clinical research because of its prenatal origin, mixed-lineage phenotype, dismal prognosis and extremely short latency. Over 90% of infant ALLs are pro-B ALL harboring the leukemic fusion MLL-AF4. Despite the fact that major achievements have provided a better understanding about the etiology of infant MLL-AF4+ ALL over the last two decades, key questions remain unanswered. Epidemiological and genetic studies suggest that the in utero origin of MLL rearrangements in infant leukemia may be the result of prenatal exposure to genotoxic compounds. In fact, chronic exposure of human embryonic stem cells (hESCs) to etoposide induces MLL rearrangements and makes hESC more prone to acquire subsequent chromosomal abnormalities than postnatal CD34+ cells, linking embryonic exposure to topoisomerase II inhibitors to genomic instability and MLL rearrangements. Unfortunately, very little is known about the nature of the target cell for transformation. Neuron-glial antigen 2 expression was initially claimed to be specifically associated with MLL rearrangements and was recently shown to be readily expressed in CD34+CD38+, but not CD34+CD38− cells suggesting that progenitors rather than stem cells may be the target cell for transformation. Importantly, the recent findings showing that MLL-AF4 rearrangement is present and expressed in mesenchymal stem cells from infant patients with MLLAF4+ ALL challenged our current view of the etiology and cellular origin of this leukemia. It becomes therefore crucial to determine where the leukemia relapses come from and how the tumor-stroma relationship is defined at the molecular level. Finally, MLL-AF4 leukemogenesis has been particularly difficult to model and bona fide MLL-AF4 disease models do not exist so far. It is likely that the current disease models are missing some essential ingredients of leukemogenesis in the human embryo/fetus. We thus propose modeling MLL-AF4+ infant pro-B ALL using prenatal hESCs. [ABSTRACT FROM AUTHOR]

Abstract: This work presents an advantageous analytical procedure for the accurate determination of free trans-resveratrol in red and white wines. The proposed method involves solid-phase extraction (SPE), acetylation of the analyte in aqueous media and further determination by gas chromatography (GC) with mass spectrometry detection (MS). The use of a mixed-mode SPE sorbent provides an improvement in the selectivity of the extraction step; moreover, the presence of several intense ions in the electron impact mass spectra of its acetyl derivative guarantees the unambiguous identification of trans-resveratrol. Considering a sample intake of 10mL, the method provides a limit of quantification (LOQ) of 0.8ngmL−1 and linear responses for concentrations up to 2.5μgmL−1, referred to wine samples. The average recovery, estimated with samples fortified at different concentrations in the above range, was 99.6% and the inter-day precision stayed below 8%. Trans-resveratrol levels in the analyzed wines varied from 3.4 to 1810ngmL−1. Cis-resveratrol was also found in all samples. In most cases, equal or higher responses were measured for this latter form than for the trans-isomer. The reduced form of resveratrol, dihydro-resveratrol, was systematically identified in red wines. [Copyright &y& Elsevier]