Formation of furan and methylfuran by maillard-type reactions in model systems and food

The formation of furan and 2-methylfuran was studied in model systems based on sugars and selected amino acids. Both compounds were preferably formed under roasting conditions in closed systems yielding up to 330 micromol of furan and 260 micromol of 2-methylfuran per mol of precursor. The amounts obtained under pressure cooking conditions were much lower, usually below 20 micromol/mol, except for 2-furaldehyde, which yielded 70-100 micromol/mol of furan. Labeling studies indicated two major formation pathways for both furans: (i) from the intact sugar skeleton and (ii) by recombination of reactive C(2) and/or C(3) fragments. Under roasting conditions in the absence of amino acids, furan was mainly formed from the intact sugar skeleton. Formic and acetic acid were identified as byproducts of sugar degradation, indicating the split off of C(1) and/or C(2) units from hexoses. The presence of alanine, threonine, or serine promoted furan formation by the recombination of C(2) fragments, such as acetaldehyde and glycolaldehyde, which may originate from both sugars and amino acids. In aqueous solution, about half of furan was generated by the recombination of sugar fragments. 2-Methylfuran was preferably formed in the presence of amino acids by aldol-type reactions of C(2) and C(3) fragments with lactaldehyde as a key intermediate, the Strecker aldehyde of threonine. The total furan levels in cooked vegetables were increased by spiking with hexoses. However, in pumpkin puree, only about 20% of furan was formed from sugars, preferably from the intact carbon skeleton.     

Mycobacterium fortuitum infection interference with Mycobacterium bovis diagnostics: natural infection cases and a pilot experimental infection

Mycobacterium fortuitum and at least 1 unidentified species of soil mycobacteria were isolated from lymph nodes from 4 of 5 African buffalo (Syncerus caffer) that had been culled because of positive test results using the Bovigam assay. The buffalo were part of a group of 16 free-ranging buffalo captured in the far north of the Kruger National Park (South Africa) assumed to be free of bovine tuberculosis. No Mycobacterium bovis was isolated. To investigate the possible cause of the apparent false-positive diagnosis, the Mycobacterium isolates were inoculated into 4 experimental cattle and their immune responses monitored over a 13-week period, using the gamma interferon assay. The immune reactivity was predominantly directed toward avian tuberculin purified protein derivative (PPD) and lasted for approximately 8 weeks. During that period 3 of 4 cattle yielded positive test results on 1 or 2 occasions. The immune responsiveness was boosted when the inoculations were repeated after 15 weeks, which led to 2 subsequent positive reactions in the experimental animal that did not react previously. Including an additional stimulatory antigen, sensitin prepared from M. fortuitum in the gamma interferon assay, showed that it was able to elicit a detectable gamma interferon response in all 4 experimentally inoculated cattle when applied in parallel with bovine and avian tuberculin PPD for the stimulation of blood samples. The implications of occasional cross-reactive responses in natural cases of infection with environmental mycobacteria in the diagnosis of bovine tuberculosis in African buffalo and cattle in South Africa are discussed.     

PAF increases phagocytic capacity and superoxide anion production in equine alveolar macrophages and blood neutrophils

Phagocytosis exerted by alveolar macrophages and neutrophils is crucial in the clearance of exogenous particles deposited in the airways. Therefore, substances that activate these phagocytes in the airways can exert important effects on the particle clearance rate. PAF, particularly, was proved to be a potent activator of several immune cells and was shown to be present in the equine lower airways in specific conditions, such as after exercise. The present study aimed to investigate if PAF is able to increase the phagocytic capacity and the production of superoxide anion in equine alveolar macrophage and blood neutrophils. The results show that PAF increased these parameters in both phagocytes even in concentrations as low as 0.1 and 1.0 nM. On that ground, the present work suggests that PAF is involved in the process of particle clearance in equine lower airways.     

Differential detection of Newcastle disease virus strains by degenerate primers based RT-PCR

Degenerate primers based RT-PCR (previously described by [Avian Dis 26 (1997) 837]) has been used for the detection and differentiation of Newcastle disease (ND) viruses. Two sets of primers (A+B and A+C), with common forward primer and distinct reverse degenerate primers, designed from fusion protein gene encoding for cleavage site, could differentiate virulent and avirulent Newcastle disease viruses (NDV). Both sets of primers amplified "F" gene sequence of virulent (velogenic and mesogenic) viruses, whereas in avirulent strains, amplification was only with primer set A+C. Total 10 NDV isolates and two clinical samples including both known and unknown pathotypes, were checked. Based on amplification results 5 viruses were found to be virulent type and 6 as avirulent with one of the two clinical samples, earlier positive by RT-PCR using non-degenerate "F" gene specific primers was found negative in this study. The technique has been found to be a simple and quick for the detection and differentiation of virulent and avirulent NDV, which is important for control of the disease in the events of the outbreaks.     

Acyl-homoserine lactones produced by Pantoea sp. isolated from the "maize white spot" foliar disease

The "maize white spot" foliar disease is a problem of increasing importance to Brazilian maize crops. A bacterium isolated from water-soaked lesions from infected maize leaves was pathogenic in biological assays in vivo. It was identified as a Gram-negative, nonsporulating, facultative anaerobic bacterium, belonging to the genus Pantoea. Chemical study of the extracts from bacterial cultivation media allowed the identification of (S)-(-)-N-butanoyl-homoserine lactone and trace amounts of N-hexanoyl-homoserine lactone, widely recognized quorum-sensing signaling substances employed in cell-to-cell communication systems. The absolute configuration of natural (S)-(-)-N-butanoyl-homoserine lactone was determined by gas chromatography-flame ionization detection with a chiral stationary phase and by comparison of circular dichroism spectroscopic data with enantiopure synthetic substances. Biological evaluations with reporter Agrobacterium tumefaciens NTL4(pZLR4) were carried out with synthetic and natural products and also with extracts from maize leaves contaminated with the isolated bacterium, as well as from healthy leaves.     

Development of a Multi-Residue Method for Monitoring 44 Pharmaceuticals in Slovene Surface Water by SPE-LC-MS/MS

The article describes a novel analytical method based on solid-phase extraction and LC-MS/MS for detection of a high number (n?=?44) of selected pharmaceuticals in surface waters. The validated method showed suitable accuracy, precision, and linearity. The extraction efficiency for pharmaceuticals was mostly above 90% and the determined LOQs were generally below 5 ng/L and even down to 0.03 ng/L. The matrix effect was successfully minimized with isotopically labeled internal standards. Six river and lake samples from Slovene regions were afterwards analyzed. Forty-two of the 44 target pharmaceuticals were detected in at least two water samples; 66% of them were detected in all samples. Three analytes were present above the LOQ in all samples: caffeine (1.1–3.1 ng/L), irbesartan (0.2–9.3 ng/L), and valsartan (0.8–47 ng/L). The highest concentration was measured for valsartan. Comprehensive comparison with the literature data showed that the found concentrations of pharmaceuticals were notably lower in our study and that a number of the pharmaceuticals had not been reported previously. Comparison of the measured and predicted (calculated) environmental concentrations of pharmaceuticals in surface waters showed high discrepancy between the two approaches, clearly indicating the need for comprehensive analytical methods for routine monitoring of these newly emerging pollutants. In conclusion, our method was proven to be adequately sensitive to reliably quantify the majority of pharmaceutical contaminants even though they were found in notably lower concentrations in Slovenian surface waters than it was predicted from their consumption and from the literature.     

The effects of lead on algae

The effects of lethal and sublethal concentrations of PbCl₂ on reproduction , viability, and motility of a marine unicellular green flagellate alga, Platymonas subcordiformis, were studied under controlled laboratory conditions. The severity of the effects depended primarily upon the concentration of Pb⁺⁺ and the duration of treatment. Log phase cells were more sensitive than stationary phase cells. Sublethal amounts of Pb (2.5 and 10 mg l^?1 Pb⁺⁺) tended to retard population growth by delaying cell division and daughter cell separation. A lethal amount of Pb (60 mg I^?1 Pb⁺) caused inhibition of growth and cell death. Various intracellular abnormalities resulted from Pb treatment. The flagella were shed or altered in a variety of ways, depending on Pb concentration; motility was least affected by low Pb and completely impaired by high Pb. Normal wild-type cells appeared to be more sensitive to Pb than mechanically sheared (flagella-less) cells and cells of a non-flagellate mutant of Platymonas. Exposure of cells to Pb in non-growth conditions of dark and cold (2°C) had little negative effect.     

Globalisation and income growth promote the Mediterranean diet

OBJECTIVE: To examine global food demand patterns and how changing diets may stimulate demand for and trade of Mediterranean diet products. DESIGN: Literature review. Trends in global and US food consumption patterns are examined and trade data are reviewed to evaluate the impact of changing diets on trade of Mediterranean diet products. Market access issues are also addressed briefly to highlight the role of policy in the trade of Mediterranean diet products. RESULTS: Diets are shifting towards higher-value products such as meats, fruits and vegetables, and a wider array of packaged food products. Trade in these products has also grown in the past two decades, with several non-traditional importers and exporters becoming increasingly active in the global market. CONCLUSIONS: Income-driven demands for quality and variety are likely to increase the demand for Mediterranean diet products globally. While the middle-income countries appear to be the best growth prospects, the USA remains a potential growth market if these products can meet the growing consumer demand for variety, quality and convenience. Although consumer trends globally indicate growth in demand for Mediterranean diet products, the additional demand may not be reflected by a corresponding growth in trade. Trade in Mediterranean diet products continues to be hampered by higher than average trade barriers and high transportation costs for perishables.     

Editorial

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