Mycotoxins inactivation by extrusion cooking of corn flour

AIMS: To evaluate the effects of the extrusion cooking process on the inactivation of mycotoxins in corn flour. METHODS AND RESULTS: Samples of corn flour experimentally contaminated with aflatoxin B1 (AFB1) (50 ppb) and deoxynivalenol (DON) (5 ppm) were extruded. The effects of three extrusion variables (flour moisture, extrusion temperature and sodium metabisulphite addition) were analysed according to a two-level factorial design. The process was effective for the reduction of DON content (higher than 95%) under all the conditions assessed, but was only partially successful (10-25%) for the decontamination of AFB1. CONCLUSION: Extrusion cooking is effective for the inactivation of DON but is of limited value for AFB1, even if metabisulphite is added. More severe extrusion conditions are needed for the detoxification of AFB1. SIGNIFICANCE AND IMPACT OF THE STUDY: As contamination with DON occurs mainly in the field prior to harvesting and that of AFB1 is normally produced during grain storage, maize is often contaminated with DON but not with AFB1. Under these conditions, the described extrusion process can be used for the detoxification of DON. The addition of sodium metabisulphite did not significantly affect the inactivation of AFB1. Extrusion cooking is therefore an appropriate treatment for vomitoxin-contaminated maize in countries where, because of the prevailing conditions, these are the only toxins present.     

Phosphoglucomutase and trehalase isoenzymes of Venezuelan simulium vectors of Onchocerca volvulus

Phosphoglucomutase (PGM) and trehalase (Tre) isoenzymes of five species of Simulium blackflies (Diptera: Simuliidae), vectors of onchocerciasis in Venezuela, were investigated by means of a portable electrophoresis field kit. Tre differed between S. incrustatum and S. oyapockense s.l. Electrophoretic variation of Tre in other members of the S. amazonicum and S. incrustatum groups merit further investigation. PGM appears to be more useful for separating populations within species complexes. Multiple populations and/or seasonal changes in population structure of S. guianense s.l., S. exiguum s.l. and S. metallicum s.l. were inferred from elecrophoretic variation of PGM.     

Conformational analysis of the Sda determinant-containing tetrasaccharide and two mimics in aqueous solution by using 1H NMR ROESY spectroscopy in combination with MD simulations

The conformational behaviour of the spacer-linked synthetic Sd^a tetrasaccharide -d-GalpNAc-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (1) and the two mimics -d-Galp-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (2) and -d-GlcpNAc-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (3) were investigated by ¹H NMR spectroscopy in combination with molecular dynamics (MD) simulations in water. Experimental 2D ¹H ROESY cross-peak intensities (ROEs) of the tetrasaccharides were compared with calculated ROEs derived from MD trajectories using the CROSREL program. Analysis of these data indicated that the oligosaccharidic skeletons of the compounds 1–3 are rather rigid, especially the -d-Hex(NAc)-(14)-[-Neu5Ac-(23)]--d-Galp fragments. The - Neu5-Ac-(23)--d-Galp linkage occurred in two different energy minima in the three-dimensional structure of the compounds 1–3 in aqueous solution. Experimental data and dynamics simulations supported the finding that the higher energy rotamer (CHEAT forcefield) was abundant in compounds 1 and 3 due to the existence of a hydrogen bond between the carboxyl group of the sialic acid and the acetamido group of the terminal monosaccharide (GalNAc or GlcNAc) unit. The conformational similarity between 1 and 3 leads to the suggestion that also their activities will be alike.     

Intracellular Glucose Concentration in Derepressed Yeast Cells Consuming Glucose Is High Enough To Reduce the Glucose Transport Rate by 50%

In Saccharomyces cerevisiae cells exhibiting high-affinity glucose transport, the glucose consumption rate at extracellular concentrations above 10 mM was only half of the zero trans-influx rate. To determine if this regulation of glucose transport might be a consequence of intracellular free glucose we developed a new method to measure intracellular glucose concentrations in cells metabolizing glucose, which compares glucose stereoisomers to correct for adhering glucose. The intracellular glucose concentration was 1.5 mM, much higher than in most earlier reports. We show that for the simplest model of a glucose carrier, this concentration is sufficient to reduce the glucose influx by 50%. We conclude that intracellular glucose is the most likely candidate for the observed regulation of glucose import and hence glycolysis. We discuss the possibility that intracellular glucose functions as a primary signal molecule in these cells.     

Phosphatidylthreonine and Lipid-Mediated Control of Parasite Virulence

The major membrane phospholipid classes, described thus far, include phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn), phosphatidylserine (PtdSer), and phosphatidylinositol (PtdIns). Here, we demonstrate the natural occurrence and genetic origin of an exclusive and rather abundant lipid, phosphatidylthreonine (PtdThr), in a common eukaryotic model parasite, Toxoplasma gondii. The parasite expresses a novel enzyme PtdThr synthase (TgPTS) to produce this lipid in its endoplasmic reticulum. Genetic disruption of TgPTS abrogates de novo synthesis of PtdThr and impairs the lytic cycle and virulence of T. gondii. The observed phenotype is caused by a reduced gliding motility, which blights the parasite egress and ensuing host cell invasion. Notably, the PTS mutant can prevent acute as well as yet-incurable chronic toxoplasmosis in a mouse model, which endorses its potential clinical utility as a metabolically attenuated vaccine. Together, the work also illustrates the functional speciation of two evolutionarily related membrane phospholipids, i.e., PtdThr and PtdSer.     

4α‐Acetoxyamijidictyol – A New Antifeeding Dolastane Diterpene from the Brazilian Brown Alga Canistrocarpus cervicornis

Chemical investigation of the CH₂Cl₂ crude extract from the brown alga Canistrocarpus cervicornis (Dictyotaceae) led to isolation of one new ( 1 ) and four previously reported dolastane diterpenes ( 2 – 5 ). Their structures were characterized by 1D‐ and 2D‐NMR spectroscopic techniques, including a full single crystal X‐ray diffraction analysis for 1, 2 , and 4 . In addition, the new structure 1 was assayed as chemical defense inhibiting the feeding by the sea urchin Lytechinus variegatus. This study constitutes an additional report broadening the known spectrum of action and defensive roles of secondary metabolites of the C. cervicornis and Dictyotales species.     

Anthropometric Characteristics,Physical Fitness and Motor Coordination of 9 to 11 Year Old Children Participating in a Wide Range of Sports

ObjectivesThe aim of this study was to investigate to what extent 9 to 11 year old children participating in a specific sport already exhibit a specific anthropometric, physical fitness and motor coordination profile, in line with the requirements of that particular sport. In addition, the profiles in children with a different training volume were compared and possible differences in training hours per week between children from a low, moderate, and high level of physical fitness and motor coordination were investigated.DiscussionThe study showed that in general, children at a young age do not exhibit sport-specific characteristics, except in children with a high training volume. It is possible that on the one hand, children have not spent enough time yet in their sport to develop sport-specific qualities. On the other hand, it could be possible that they do not take individual qualities into account when choosing a sport.     

Conflict in Protected Areas: Who Says Co-Management Does Not Work?

Natural resource-related conflicts can be extremely destructive and undermine environmental protection. Since the 1990s co-management schemes, whereby the management of resources is shared by public and/or private sector stakeholders, have been a main strategy for reducing these conflicts worldwide. Despite initial high hopes, in recent years co-management has been perceived as falling short of expectations. However, systematic assessments of its role in conflict prevention or mitigation are non-existent. Interviews with 584 residents from ten protected areas in Colombia revealed that co-management can be successful in reducing conflict at grassroots level, as long as some critical enabling conditions, such as effective participation in the co-management process, are fulfilled not only on paper but also by praxis. We hope these findings will re-incentivize global efforts to make co-management work in protected areas and other common pool resource contexts, such as fisheries, agriculture, forestry and water management.     

Orientation Transfer in Vernier and Stereoacuity Training

Human performance on various visual tasks can be improved substantially via training. However, the enhancements are frequently specific to relatively low-level stimulus dimensions. While such specificity has often been thought to be indicative of a low-level neural locus of learning, recent research suggests that these same effects can be accounted for by changes in higher-level areas–in particular in the way higher-level areas read out information from lower-level areas in the service of highly practiced decisions. Here we contrast the degree of orientation transfer seen after training on two different tasks—vernier acuity and stereoacuity. Importantly, while the decision rule that could improve vernier acuity (i.e. a discriminant in the image plane) would not be transferable across orientations, the simplest rule that could be learned to solve the stereoacuity task (i.e. a discriminant in the depth plane) would be insensitive to changes in orientation. Thus, given a read-out hypothesis, more substantial transfer would be expected as a result of stereoacuity than vernier acuity training. To test this prediction, participants were trained (7500 total trials) on either a stereoacuity (N = 9) or vernier acuity (N = 7) task with the stimuli in either a vertical or horizontal configuration (balanced across participants). Following training, transfer to the untrained orientation was assessed. As predicted, evidence for relatively orientation specific learning was observed in vernier trained participants, while no evidence of specificity was observed in stereo trained participants. These results build upon the emerging view that perceptual learning (even very specific learning effects) may reflect changes in inferences made by high-level areas, rather than necessarily fully reflecting changes in the receptive field properties of low-level areas.     

Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions

80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008–2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management—organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15–75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological knowledge from data rich countries to countries with limited soil data.