Solar Photocatalysis Using Fixed-Film TiO<Subscript>2</Subscript> for Microcystins from Colonial <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis>

Microcystins (MCs) are endotoxins produced by cyanobacteria in freshwaters globally. With known potential for human health risks, rapid and effective treatment methods are needed for MCs. Previous studies have shown photocatalysis can achieve rapid half-lives with UV lamps and slurries of TiO₂. In this experiment, rates and extents of solar photocatalysis of MCs were measured using bench-scale reactors with fixed films of TiO₂ for solutions with a range of cellular:aqueous MC ratios. Since cellular MCs can be removed physically, photocatalysis rates were measured following sand filtration to discern the extent of MC removal post-filtration. Since UV energy drives photocatalysis using TiO₂, rates of removal were calculated as a function of cumulative UV insolation and time. For water containing < 10% aqueous MC, filtration removed 90% of total MC, and the subsequent photocatalysis half-life was 0.37 MJ/m² (or 111 min). For water with ~?50% aqueous MCs, filtration removed 52% of the total MCs, and the average half-life for photocatalysis was 0.38 MJ/m² (or 138 min). For the >?90% aqueous MC treatment, filtration removed 0% MCs, and the photocatalysis half-life for MCs was 0.37 MJ/m² (or 135 min). Previous studies have used clarified waters; however, results from this study are likely representative of scenarios with waters containing confounding water characteristics and use of solar light for UV, as anticipated in developing countries with less advanced water treatment methods. Photocatalysis is a rapid and effective process for decreasing concentrations of MCs and could be useful for mitigating risks from MC exposures in drinking water.     

Chemical composition and pasting properties of einkorn (Triticum monococcum L. subsp. monococcum) whole meal flour

Einkorn (Triticum monococcum L. subsp. monococcum) is an ancient wheat appreciated for its high proteins, carotenoids and tocols content. To better understand its potential for human consumption and food preparation, composition and pasting properties of 65 einkorn accessions, of different geographical origin but cultivated at S. Angelo Lodigiano (Italy), were evaluated. Eight Triticum turgidum and seven Triticum aestivum cultivars, belonging to different subspecies, were assessed as controls.On average, the einkorn samples had light seeds (25.0 mg/kernel), extra-soft texture (238.3 g), high protein content (18.2%), high ash content (2.35%), low SDS sedimentation volume (25.6 ml), high carotenoids (8.36 μg/g) and high yellow pigments (8.46 μg/g). The pasting parameters studied were peak viscosity (average: 2426 cP), breakdown (765 cP), final viscosity (2788 cP) and setback (1126 cP). Total amylose (25.7%) and total starch (65.5%) were also measured. Significant differences from the controls and a broad variation for all the traits analysed were observed. Einkorns from diverse geographical areas showed different mean values for all characters, apart from ash content.The good pasting properties, coupled with high proteins and carotenoids content, suggest that einkorn is particularly suited for the production of baby and specialty foods.     

Chemical markers for the evaluation of raw material hygienic quality in egg products

The aim of this research was to study uracil and lactic and acetic acids as chemical markers for hygienic quality evaluation of raw material in liquid pasteurized egg products. Uracil, absent in sound whole eggs, was formed in raw and pasteurized egg products as a consequence of high microbial contamination (>10(6) cfu/g) after a sufficient lag time, remaining stable at 4 degrees C but disappearing after 7 days of storage at 25 degrees C. Both lactic and acetic acids, starting from initial values of 1-7 mg/kg dry matter, presented trends similar to that of uracil; however, acetic acid never decreased during the storage of raw egg products. With few exceptions, all three metabolites were produced by Enterobacter cloacae, Escherichia coli, Morganella morganii, Serratia liquefaciens, Aeromonas hydrophyla, Pseudomonas fluorescens, Enterococcus avium, and Enterococcus faecalis, separately inoculated in whole egg samples. Uracil seems to be the most sensible marker, with a suggested limit corresponding to the detectable level.     

Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

The annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.     

Characterizing historical and modern fire regimes in Michigan (USA): A landscape ecosystem approach

We studied the relationships of landscape ecosystems to historical and contemporary fire regimes across 4.3 million hectares in northern lower Michigan (USA). Changes in fire regimes were documented by comparing historical fire rotations in different landscape ecosystems to those occurring between 1985 and 2000. Previously published data and a synthesis of the literature were used to identify six forest-replacement fire regime categories with fire rotations ranging from very short (<100 years) to very long (>1,000 years). We derived spatially-explicit estimates of the susceptibility of landscape ecosystems to fire disturbance using Landtype Association maps as initial units of investigation. Each Landtype Association polygon was assigned to a fire regime category based on associations of ecological factors known to influence fire regimes. Spatial statistics were used to interpolate fire points recorded by the General Land Office. Historical fire rotations were determined by calculating the area burned for each category of fire regime and dividing this area by fifteen (years) to estimate area burned per annum. Modern fire rotations were estimated using data on fire location and size obtained from federal and state agencies. Landtype Associations networked into fire regime categories exhibited differences in both historical and modern fire rotations. Historical rotations varied by 23-fold across all fire rotation categories, and modern forest fire rotations by 13-fold. Modern fire rotations were an order of magnitude longer than historical rotations. The magnitude of these changes has important implications for forest health and understanding of ecological processes in most of the fire rotation categories that we identified.This revised version was published online in May 2005 with corrections to the Cover Date.     

Factors influencing the occurrence of fall armyworm parasitoids in Zambia

Journal of Pest Science - Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and...     

Polyphenol oxidase,alpha-amylase and beta-amylase activities of Triticum monococcum, Triticum turgidum and Triticum aestivum: A two-year study

Enzymatic activity often reduces the nutritional value of wheat flour during food manufacturing, causing compound degradation and/or heat damage. The choice of wheat varieties with low enzymatic activity could therefore help to preserve the nutritional quality of food. The aim of this research was to evaluate polyphenol oxidase, alpha-amylase and beta-amylase activities in whole meal flours of 59 accessions belonging to different wheat species and subspecies, cropped in two years. The extraction pH (7.0), reaction pH (5.5) and reaction temperature (45 °C) were determined by preliminary trials. The ANOVA highlighted significant differences for all enzymes among species/subspecies and, for amylases, between cropping years; however, the year influence was overwhelming only for alpha-amylase. Einkorn showed the highest polyphenol oxidase (362.1 ± 9.46 U/g DM) as well as the lowest alpha-amylase (0.20 ± 0.006 CU/g DM) and beta-amylase (12.0 ± 0.36 B3U/g DM) activities. The embryo/scutellum had the highest polyphenol oxidase and alpha-amylase values, followed by the bran and the endosperm; in contrast, beta-amylase was evenly distributed in the bran and the endosperm, and was absent in the embryo/scutellum.     

Uracil as an index of lactic acid bacteria contamination of tomato products

The aim of this research was to evaluate the suitability of uracil as an hygienic quality index of tomato products. Whereas uridine was naturally present throughout tomato fruits' ripening, uracil appeared only after microbial contamination. In tomato pulp inoculated with nine different microbial strains, all five lactic acid bacteria (LAB) studied released relevant quantities of uracil (150-1040 mg/kg of dm), with a correlated partial or total decrease of uridine. Uracil production by yeasts and molds was very low or nonexistent; the starting uridine concentration (approximately 960 mg/kg of dm) remained constant or increased. Uracil thermostability was also verified. Twenty-six samples of tomato paste (30 degrees Brix) were collected from bag-in-drums produced in an industrial processing plant, some with evident swelling symptoms. All of the samples with high microbial count presented uracil. Uracil was also present in samples with microbial contamination under the detection limit and Howard mold count below legislation limits, implying the reprocessing, at least partial, of altered tomato product. The results indicate that uracil presence in tomato products is an index of LAB contamination that has occurred before heat treatment.