Joanna Leszczyńska

Aflatoxins in nuts assayed by immunological methods.

Abstract Different kinds of raw and processed nuts available in the local retail market were investigated for aflatoxin content. Total aflatoxins and aflatoxin B1 content were determined by immunoaffinity chromatography with fluorescence detection after reaction with bromine solution and by immunoenzymatic test kits. Of 29 investigated samples, 38% were contaminated. The total aflatoxin content in contaminated samples was between 1.20 μg/kg for peanuts and 5.50 μg/kg for walnuts. The concentration of aflatoxin B1 found in contaminated samples was between 0.35 μg/kg for cashew nuts and 4.04 μg/kg for walnuts. The mean recovery of total aflatoxins was 95% for the Ridascreen test and 92% for immunoaffinity chromatography with fluorescence detection. For aflatoxin B1 the mean recovery was 84%.

The use of transglutaminase in the reduction of immunoreactivity of wheat flour

Abstract The immune response of wheat flour modified by the treatment with transglutaminase under different conditions of temperature, incubation periods and the ratio of enzyme/wheat flour was investigated. The particular wheat protein fractions were examined for the immune reaction by the use of an indirect non-competitive ELISA. Commercially available antibodies, namely, monoclonal antihuman IgG and monoclonal antihuman IgE conjugates with alkaline phosphatase and human sera with elevated IgG as well as rabbit sera against QQQPP peptide were tested. The highest decrease in gliadins immunoreactivity was observed for wheat flour modified under following conditions: temperature 37°C, 18 h of incubation and the ratio enzyme/wheat flour 1:10 000. For all rabbit sera examined the residual immunoreactivity of glutenins was found to be below 30% of the level measured for the untreated protein. The large decrease in allergenicity of glutenins leads to the conclusion that wheat flour modified by treatment with transglutaminase may be used as a constituent of food products destined for people with a classic food allergy, i.e. the allergy elicited by that protein fraction.

Production of the Allergenic Protein Alt a 1 by Alternaria Isolates from Working Environments

The aim of the study was to evaluate the ability of Alternaria isolates from workplaces to produce Alt a 1 allergenic protein, and to analyze whether technical materials (cellulose, compost, leather) present within the working environment stimulate or inhibit Alt a 1 production (ELISA test). Studies included identification of the isolated molds by nucleotide sequences analyzing of the ITS1/ITS2 regions, actin, calmodulin and Alt a 1 genes. It has been shown that Alternaria molds are significant part of microbiocenosis in the archive, museum, library, composting plant and tannery (14%–16% frequency in the air). The presence of the gene encoding the Alt a 1 protein has been detected for the strains: Alternaria alternata, A. lini, A. limoniasperae A. nobilis and A. tenuissima. Environmental strains produced Alt a 1 at higher concentrations (1.103–6.528 ng/mL) than a ATCC strain (0.551–0.975 ng/mL). It has been shown that the homogenization of the mycelium and the use of ultrafiltration allow a considerable increase of Alt a 1 concentration. Variations in the production of Alt a 1 protein, depend on the strain and extraction methods. These studies revealed no impact of the technical material from the workplaces on the production of Alt a 1 protein.

Decrease of wheat flour allergenicity via lactic acid fermentation

Abstract Results of the research on the lowering of allergenicity of wheat flour fermented using homo- and heterofermentative lactic acid bacteria and mixed cultures with yeast were discussed. The gliadins’ immunoreactivity was measured using the indirect non-competitive enzyme-linked immunosorbent assay method. The biggest decrease of the immunoreactivity of gliadin fraction was observed in the case of fermentation performed with the use of mixed cultures of lactic acid bacteria and yeast. This way of wheat flour modification seems to be promising, because fermentation is a natural process causing not only lowering of the allergenicity, but also improving organoleptic and nutritional values of obtained products.

Influence of combined use of iodide and compost on Hg accumulation by Lepidium sativum L.

This study focuses on the influence of adding iodide (KI) and compost in different soil/compost ratios on the efficiency of Hg phytoextraction by Lepidium sativum L. Plant growth and non-enzymatic antioxidants are studied to understand metabolic plant adaptations to Hg stress during soil reclamation and their relations to Hg accumulation. Due to the use of relatively high chelant dosages in current plant-based soil remediation techniques and associated environmental risks, it is necessary to explore alternative approaches to the phytoextraction of Hg from contaminated soils. The results show a coordinated increase in non-enzymatic antioxidants in plants cultivated in growing media containing polluted soil, compost and KI. This indicates that the non-enzymatic antioxidative defence system of L. sativum L. is involved in its strategy to survive conditions of mercury-induced stress. Adding compost and iodide to Hg polluted soil also increases the total accumulation of Hg by L. sativum L. and the translocation of pollutants to aerial plant tissues. Simultaneous application of compost and KI promoted the Hg accumulation by L. sativum L. in a pot experiment.

Allergenic Potential of Tomatoes Cultivated in Organic and Conventional Systems.

Tomatoes (Lycopersicon esculentum Mill.) are a widely consumed vegetables and contain many health beneficial micronutrients. Unfortunately, they may also cause adverse allergic reactions in sensitized people. Many studies, conducted in recent years, indicate that organically produced vegetables have higher nutritional value, improved sensory quality and contain more health-enhancing bioactive compounds than vegetables grown under the conventional system. However, the relation between organic methods of cultivation and allergenic potential of tomatoes has received little scientific attention. This study analyzed samples of five tomato cultivars taken from organic and conventional systems over three consecutive years. The content of profilin, Bet v 1 and lipid transfer protein (LTP) analogues in tomato samples was determined using an indirect ELISA assay. Substantial quantities of these proteins were found in certain cultivars across all three years of cultivation. On the basis of these findings, organically grown tomatoes appear to offer little advantage over conventionally cultivated plants in terms of reduced allergenic potential.

Protein changes in Lepidium sativum L. exposed to Hg during soil phytoremediation

ABSTRACT Some investigations have been carried out in this study to find the best technique of soil reclamation in mercurypolluted soil. In this study, we examined Lepidium sativum L. as a plant useful for Hg phytoextraction. The simultaneous application of compost and thiosulfate was explored as a possible method of enhancing the process of phytoextraction. The results of the investigations of plant protein changes during assisted Hg phytoextraction were also provided. The results of the study show that combined use of compost and thiosulfate significantly increased both the total Hg accumulation and its translocation to aerial plant tissues. Plant protein analysis showed that L. sativum L. has the ability to respond to environmental stress condition by the activation of additional proteins. The additional proteins, like homocysteine methyltransferase, ribulose bisphosphate carboxylases (long and short chains), 14-3-3-like protein, and biosynthesis-related 40S ribosomal protein S15, were activated in plant shoots only in experiments carried out in Hg-polluted soil. There were no protein changes observed in plants exposed to compost and thiosulfate. It suggests that the combined use of compost and thiosulfate decreased Hg toxicity.

Photosynthetic pigments and peroxidase activity of Lepidium sativum L. during assisted Hg phytoextraction

The study was conducted to evaluate metabolic answer of Lepidium sativum L. on Hg, compost, and citric acid during assisted phytoextraction. The chlorophyll a and b contents, total carotenoids, and activity of peroxidase were determined in plants exposed to Hg and soil amendments. Hg accumulation in plant shoots was also investigated. The pot experiments were provided in soil artificially contaminated by Hg and/or supplemented with compost and citric acid. Hg concentration in plant shoots and soil substrates was determined by cold vapor atomic absorption spectroscopy (CV-AAS) method after acid mineralization. The plant photosynthetic pigments and peroxidase activity were measured by standard spectrophotometric methods. The study shows that L. sativum L. accumulated Hg in its aerial tissues. An increase in Hg accumulation was noticed when soil was supplemented with compost and citric acid. Increasing Hg concentration in plant shoots was correlated with enhanced activation of peroxidase activity and changes in total carotenoid concentration. Combined use of compost and citric acid also decreased the chlorophyll a and b contents in plant leaves. Presented study reveals that L. sativum L. is capable of tolerating Hg and its use during phytoextraction assisted by combined use of compost and citric acid lead to decreasing soil contamination by Hg.

Hypoallergenic wheat bread: response to an emerging issue

The increasing prevalence of gluten intolerance raises the need to broaden the range of products that are suitable for coeliac. Usually, this means creating gluten-free (GF) products. However, limited amounts of wheat can be consumed safely by some people with moderate gluten intolerance. In this study, we attempted to produce high-quality bread with reduced immunoreactivity of wheat flour proteins by the partial replacement of wheat flour with wheat starch and by use of lactic acid fermentation. The resulting bread immunoreactivity was determined using the enzyme-linked immunosorbent assay (ELISA) method and compared to that of regular wheat bread. The combination of flour mixture modification and fermentation lowered the immune response in digested bread samples by more than 90% in the case of anti-QQQPP peptide antibodies and by over 40% for human anti-gliadin antibodies.

The effect of enzymatic modification and genetic background on wheat gliadin immunological properties

Abstract The immune response to gliadins extracted from 35 wheat cultivars, strains and species was investigated. With the use of a non-competitive ELISA method, we sought to examine if immune reaction occurs between wheat proteins and sera from patients sensitive to gluten, as well as between wheat proteins and rabbit antibodies against pentapeptide QQQPP. Results showed considerable differences among cultivars. Breeding strains STH 183, STH 650, STH 2804, Triticum aethiopicum and Triticum durum showed the lowest immunoreactivity of the native samples. Seventeen of selected wheat flour samples were subjected to enzymatic modifications by subtilisin and transglutaminase. Samples modified by subtilisin exhibited the most extensive change in the level of immunoreactivity of gliadin proteins. The lowest immunoreactivity was reported for the breeding strains STH 1596, STH 2804 and cultivars Tonacja and Zyta. One wheat cultivar (Tonacja), known for its high native gliadin immunoreactivity, was shown to be very susceptible to enzymatic digestion, which resulted in a reduction of its initial immunoreactivity level to low values. Immunoreactivity analysis was also conducted on extracted gliadin fractions from winter wheat strain Ostka strzelecka. The highest level of immunoreactivity to both types of antibodies we used was indicated for ω5-gliadins. It was, however, abrogated in the aftermath of enzymatic modifications.