Latex proteins from the plant Calotropis procera are partially digested upon in vitro enzymatic action and are not immunologically detected in fecal material

Soluble proteins from the latex of Calotropis procera (LP) were investigated in vitro and in vivo for digestibility as the latex has previously been shown to produce considerable toxic effects on animals. The latex is also an important biologically active compound that displays antiinflammatory and antidiarrhea properties. The proteins were digested by the action of trypsin, pepsin or chemotrypsin as revealed by gel filtration and SDS-PAGE analysis. Furthermore, the full LP digestion was easily achieved by protease treatment. Rabbit polyclonal antibodies raised against LP failed to detect cross-reactive molecules in fecal material of experimental rats following 35 consecutive days of LP consumption in water. Similar patterns of electrophoresis were observed for the negligible amounts of protein observed in the fecal extracts of control and test animals. No death or toxic effects were observed among animals. Taken together these results suggest that harmful and toxic effects on animals of the latex from C. procera are present in its rubber and low molecular weight fractions rather than its protein content.     

Distribution and composition of phytosterols and steryl ferulates in wheat grain and bran fractions

Phytosterols and steryl ferulates are bioactive compounds accumulating in the bran and germ of wheat. However, little is known regarding their localisation and composition in the bran layers of the kernel. The aim of this study was to determine the distribution of phytosterols and steryl ferulates in the wheat grain and in the different layers of bran. The wheat fractions, produced by conventional debranning, aleurone separation and a novel electrostatic process, were analysed for phytosterol contents using GC–FID and for steryl ferulate contents using HPLC–UV. The compounds were identified by GC– and LC–MS. Phytosterols and steryl ferulates were concentrated in the bran layers. The steryl ferulates were accumulated in the intermediate layers, whereas the phytosterols were more evenly distributed in the intermediate layers and aleurone cell contents. The phytosterol composition varied within the wheat kernel, while the steryl ferulate composition was similar in different fractions. Sitosterol and campestanyl ferulate were the main compounds. The highest levels of phytosterols (up to 2117 μg/g) and steryl ferulates (up to 703 μg/g) were found in the pearling, aleurone and certain bran fractions. The phytosterol-rich fractions could be utilised in cereal foods to enhance the intake of health-promoting compounds from natural sources.     

Delaying weed adaptation to herbicide by environmental heterogeneity: a simulation approach

BACKGROUND: Environmental heterogeneity in space or time can drive the evolutionary trajectory of an adaptive trait. This concept could be of practical significance in pesticide resistance management that aims to delay the evolution of a resistance allele. Using a population genetics model, the dynamics of herbicide resistance in a weed species was simulated in a heterogeneous environment with alternation of two unrelated herbicides in time, in space or in both time and space. The level of the environmental heterogeneity (habitat grain) was simulated by a variation in the size of the herbicide-treated areas. RESULTS: The model confirms that several strategies based on habitat heterogeneity efficiently slow down and even prevent resistance evolution. For a recessive resistant trait in outcrossing species, a medium level of environmental heterogeneity (intermediate habitat grain) was found to be the best for delaying herbicide resistance, as previously observed for insecticide resistance management. In selfing species or for a dominant resistant trait in outcrossing species, a low level of environmental heterogeneity (coarse-grained habitat) was more efficient in delaying resistance evolution when heterogeneity in both space and time were considered. CONCLUSION: This model suggests that the choice of optimal tactics for delaying herbicide resistance by enhanced heterogeneity in space or time firstly depends on the interactions between the breeding system and the dominance of the resistance allele in the presence of herbicide, then on the value of the fitness cost and lastly on the dominance of this fitness cost.     

Anti-Inflammatory Activity of Chitooligosaccharides in Vivo

All the reports to date on the anti-inflammatory activity of chitooligosaccharides (COS) are mostly based on in vitro methods. In this work, the anti-inflammatory activity of two COS mixtures is characterized in vivo (using balb/c mice), following the carrageenan-induced paw edema method. This is a widely accepted animal model of acute inflammation to evaluate the anti-inflammatory effect of drugs. Our data suggest that COS possess anti-inflammatory activity, which is dependent on dose and, at higher doses, also on the molecular weight. A single dose of 500 mg/kg b.w. weight may be suitable to treat acute inflammation cases; however, further studies are needed to ascertain the effect upon longer inflammation periods as well as studies upon the bioavailability of these compounds.     

Recovery threshold of Toxocara canis eggs from soil

The purpose of this study was to evaluate the threshold of Toxocara canis eggs form soil samples through utilisation of a centrifuge-flotation technique (CFT). Aliquots of soil (1 g each) were artificially contaminated with known numbers of T. canis eggs (1, 10, 25, 50, 100, and 200 eggs). The threshold was evaluated based on a CFT using zinc sulphate (Zn₂SO₄) and sodium nitrate (Na₂NO₃) solutions at a specific gravity of 1.20. The number of eggs recovered was directly proportional to the number of eggs employed to seed the soil. Both solutions enabled full recovery of samples containing merely three eggs; only Zn₂SO₄ demonstrated efficiency in soil contaminated with a single egg. A recovery rate of 100% was obtained for all tests with samples containing 10 and 25 eggs for Zn₂SO₄ and Na₂NO₃, respectively_. There was no difference in the mean number of recovered eggs regarding either the efficacy of the solutions or the repetition of evaluations in the same trial (p > 0.05). Therefore, the CFT is efficient for the detection of Toxocara eggs, even in samples containing low egg numbers.     

Soil pollution by nonylphenol and nonylphenol ethoxylates and their effects to plants and invertebrates

Background, aim, and scope  

Nonylphenol polyethoxylates (NPEOs) are a widely used class of nonionic surfactants known to be toxic and endocrine-disrupting contaminants. Their use and production have been banned in the European Union and substituted by other surfactants considered as environmentally safer. However, their use continues in many countries without any legal control. Discharges of effluents from wastewater treatment plants and the application of sewage sludge application, landfilling, and accidental spillage to soils are the major sources of NPEOs in the environment. The biodegradation of these surfactants is relatively easy, leading to the accumulation of the simplest chemical forms of nonylphenol ethoxylates (NP, NP1EO, and NP2EO) and nonylphenol carboxy acids (NP2EC or NP1EC). However, these are also the most toxic end-products and have a higher environmental persistence. Compared to aquatic ecosystems, not much is known about the effects of NPEOs in terrestrial organisms, with few studies mainly centered on the effects on plants and soil microorganisms. The main aim of this study is to provide the range of concentrations of NPEOs with ecotoxicological effects on different plants and soil invertebrate species. In addition, we aim to identify the main soil properties influencing their toxicity.     

Synthesis and Biological Activities of Cyclodepsipeptides of Aurilide Family from Marine Origin

Aurilides are a class of depsipeptides occurring mainly in marine cyanobacteria. Members of the aurilide family have shown to exhibit strong cytotoxicity against various cancer cell lines. These compounds bear a pentapeptide, a polyketide, and an α-hydroxy ester subunit in their structure. A large number of remarkable studies on aurilides have emerged since 1996. This comprehensive account summarizes the biological activities and total syntheses of natural compounds of the aurilide family as well as their synthetic analogues.     

A new vision-based approach to differential spraying in precision agriculture

One of the objectives of precision agriculture is to minimize the volume of herbicides by using site-specific weed management systems. To reach this goal, two major factors need to be considered: (1) the similarity of spectral signatures, shapes, and textures between weeds and crops and (2) irregular distribution of weeds within the crop. This paper outlines an automatic computer vision method for detecting Avena sterilis, a noxious weed growing in cereal crops, and differential spraying to control the weed. The proposed method determines the quantity and distribution of weeds in the crop fields and applies a decision-making strategy for selective spraying, which forms the main focus of the paper. The method consists of two stages: image segmentation and decision-making. The image segmentation process extracts cells from the image as the low-level units. The quantity and distribution of weeds in the cell are mapped as area and structural based attributes, respectively. From these attributes, a multicriteria decision-making approach under a fuzzy context allows us to decide whether any given cell needs to be sprayed. The method was compared with other existing strategies.     

Anti-Leishmania IgA in urine samples from dogs with clinical leishmaniasis

Recently, anti-Leishmania IgG has been detected in urine samples from Leishmania-infected dogs and its concentrations have been correlated with impairment of renal function. The presence and relationship with other anti-Leishmania Ig isotypes in urine have not yet been investigated. The current study analyzed the concentrations of anti-Leishmania IgA and IgG in sera (Ig-S) and urine (Ig-U) samples by ELISA in 64 untreated dogs with clinical leishmaniasis. All 64 serum samples tested were positive for anti-Leishmania IgG. Fifty of them (78.1%) were also positive for anti-Leishmania IgA. The results showed the presence of anti-Leishmania IgA-U in 38% of the 50 dogs that were positive for specific IgA-S. Thirty-eight of the 64 dogs positive for Leishmania-specific IgG-S (59.4%) were also positive for Leishmania-specific IgG in urine (IgG-U). The concentrations of anti-Leishmania IgA-U were significantly correlated with urine protein/creatinine (uP/C) ratio (ρ = 0.542; P < 0.001) and with serum biochemical parameters, such as γ-globulins, urea and creatinine. Goldmann–Witmer coefficient (C value) indicated that detection of specific IgA in urine samples from dogs with leishmaniasis might not only be due to impairment of filtration of the glomerular barrier but also be due to local production of this isotype, which might reflect a local immunological response to the presence of the parasite in the genitourinary tract. Anti-Leishmania IgG-U concentrations were highly correlated with uP/C ratio (ρ = 0.779; P < 0.001) and C value did not support in any case local production of this isotype. IgG isotype might be a more suitable and specific tool to evaluate renal damage due to the lower IgA-U sensitivity and correlation coefficients and evidence of IgA local production. However, dogs found positive for both Ig isotypes in urine presented significantly higher specific IgG-U concentrations and higher uP/C ratios than dogs found positive only for IgG-U, thus suggesting that the first group suffered more severe renal damage. This fact makes it necessary to evaluate the prognosis of dogs showing both anti-Leishmania IgA-U and IgG-U in future studies.