Antibacterial activity and mode of action of selected glucosinolate hydrolysis products against bacterial pathogens

Plants contain numerous components that are important sources of new bioactive molecules with antimicrobial properties. Isothiocyanates (ITCs) are plant secondary metabolites found in cruciferous vegetables that are arising as promising antimicrobial agents in food industry. The aim of this study was to assess the antibacterial activity of two isothiocyanates (ITCs), allylisothiocyanate (AITC) and 2-phenylethylisothiocyanate (PEITC) against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. The antibacterial mode of action was also characterized by the assessment of different physiological indices: membrane integrity, intracellular potassium release, physicochemical surface properties and surface charge. The minimum inhibitory concentration (MIC) of AITC and PEITC was 100 g/mL for all bacteria. The minimum bactericidal concentration (MBC) of the ITCs was at least 10 times higher than the MIC. Both AITC and PEITC changed the membrane properties of the bacteria decreasing their surface charge and compromising the integrity of the cytoplasmatic membrane with consequent potassium leakage and propidium iodide uptake. The surface hydrophobicity was also non-specifically altered (E. coli and L. monocytogenes become less hydrophilic; P. aeruginosa and S. aureus become more hydrophilic). This study shows that AITC and PEITC have strong antimicrobial potential against the bacteria tested, through the disruption of the bacterial cell membranes. Moreover, phytochemicals are highlighted as a valuable sustainable source of new bioactive products.This work was supported by the Operational Programme for Competitiveness Factors - COMPETE and by the Portuguese Foundation for Science and Technology through Project Phytodisinfectants - PTDC/DTP-SAP/1078/2012 (COMPETE: FCOMP-01-0124-FEDER-028765), the PhD grant awarded to Ana Abreu (SFRH/BD/84393/2012), and the post-doctoral grants awarded to Anabela Borges (SFRH/BPD/98684/2013) and Lucia C. Simoes (SFRH/BPD/81982/2011). Also, this work was undertaken as part of the European Research Project SUSCLEAN (Contract no FP7-KBBE-2011-5, project number: 287514) and the COST Action FA1202. The authors are solely responsible for this work. It does not represent the opinion of the European Community, and the Community is not responsible for any use that might be made of data appearing herein

Pleurotus ostreatus as a source of beta-D-glucans

W pracy scharakteryzowano aktywność biologiczną ß-glukanów zawartych w grzybach wyższych, szczególnie w boczniaku ostrygowatym. ß-glukany są to naturalne polisacharydy stymulujące układ immunologiczny przede wszystkim poprzez aktywację makrofagów. Ponadto selektywnie obniżają poziom cholesterolu LDL we krwi. W boczniaku ostrygowatym występuje pleuran, który charakteryzuje się wysoką aktywnością biologiczną. Na aktywność tę wpływają także inne związki zawarte w boczniaku m.in. chityna i chitozan.In the paper, the biological activity of beta-glucanes present in higher fungi, especially in Pleurotus ostreatus, was characterized. Beta-glucanes are natural polysaccharides, which stimulate the immune system mainly by activating macrophages. Moreover, they selectively reduce the level of LDL cholesterol in blood. Pleuran is contained in Pleurotus ostreatus; it is characterized by a high biological activity. Its biological activity is impacted by other compounds contained in Pleurotus ostreatus, among other things, by chitin and chitosan

Rola zywnosci pochodzenia roslinnego w zapobieganiu chorobom cywilizacyjnym

Authors identified nutritional and clinical risks and investigated their effect on population health in Slovakia within more than the last 40 years. The results were supported by nationally representative, nutrition researches conducted on more than 20 000 people. Simultaneously, the following factors were studied: average lipid blood levels; prevalence of dyslipidaemia, obesity, diabetes mellitus (DM) and colorectal carcinoma in Slovak Republic; and the results of 4 dietetic tests (pectin + ascorbic acid, essential phospholipids, powder from Pleurotus ostreatus, and flavonoid preparation). As a result some improvement measures were suggested for the population in terms of nutrition, some regulation changes were proposed in food and nutritional policy, and finally some proposals were addressed to food processors.Autorzy określili aktualne zagrożenia żywieniowe i kliniczne, badając ich wpływ na stan zdrowotny populacji ludności Słowacji w ciągu ponad czterdziestu lat. Wyniki uzupełniono rezultatami badań żywieniowych przeprowadzonych w skali kraju na grupie ponad 20 000 osób. Jednocześnie przeanalizowano: średni poziom lipidów we krwi, powszechność występowania takich zjawisk, jak: zaburzenia obecności tłuszczu we krwi, otyłość, cukrzyca i rak jelita grubego. Zamieszczono również wyniki czterech testów dietetycznych (diety uzupełnianej pektyną i kwasem askorbinowym, fosfolipidami, sproszkowanym boczniakiem ostrygowatym (Pleurotus ostreatus) oraz związkami flawonoidowymi). Na podstawie badań zaproponowano poprawę sposobu odżywiania się, zmiany przepisów dotyczące polityki żywnościowej i sposobu żywienia oraz przedstawiono sugestie odnoszące się do produkcji żywności

Effect of household and industrial processing on levels of some pesticide residues in carrots

Pesticides are widely used in conventional agriculture to obtain a better yield for crops. They can cause toxic effects (headaches, cancer, reproductive harm and endocrine disruption). The main exposure to pesticides for humans is via food (especially by fruit and vegetables). Processing food can affect the level of pesticide residues and in some special case, more toxic by-products can be formed during processing. Different studies have been related to measure concentrations of pesticide residues after home or industrial processing. However, many processing factors (residues level in processed commodity/residue level in raw commodity) remain unknown and are necessary to estimate the level of pesticide exposure at the point of consumption after processing. To reach this objective, the combination carrots/pesticides (boscalid, chlorpyrifos, difenoconazole, dimethoate, linuron and tebuconazole) was chosen in collaboration with the Belgian Federal Agency for Safety of the Food Chain based on the number of non compliant samples, frequency and concentration level observed and on the toxicity of the pesticides. Treated carrots were grown in Belgium by Redebel sa. The amount of the pesticide residues observed in the raw material varied due to the different treatments, application times, weather conditions, the physico-chemical properties of each pesticide. Food processing (washing, peeling, blanching, microwave cooking, pasteurization and sterilization) was carried out on industrial pilot scale. Pesticides and the degradation products formed during processing were analyzed with GC–MS/MS and UHPLC–MS/MS. The washing step allowed decreasing the concentration of residues for all pesticides up to ~90%. The second process, peeling, results in a reduction comparable to washing. The blanching step, combining heat with a large quantity of water, enhanced the elimination of residues. Even residual concentrations were below 5 ppb, it was observed that microwave cooking did not reduce the level of residues while in-pack sterilization decreased most of the pesticide residues still present except difenoconazole. To conclude, most of the processing factors could be explained in terms of water solubility, the log-octanol-water-partitioning coefficients, the systemic properties of the pesticides studied and the agricultural practices.</p

Nestin expression in the cell lines derived from glioblastoma multiforme

<p>Abstract</p> <p>Background</p> <p>Nestin is a protein belonging to class VI of intermediate filaments that is produced in stem/progenitor cells in the mammalian CNS during development and is consecutively replaced by other intermediate filament proteins (neurofilaments, GFAP). Down-regulated nestin may be re-expressed in the adult organism under certain pathological conditions (brain injury, ischemia, inflammation, neoplastic transformation). Our work focused on a detailed study of the nestin cytoskeleton in cell lines derived from glioblastoma multiforme, because re-expression of nestin together with down-regulation of GFAP has been previously reported in this type of brain tumor.</p> <p>Methods</p> <p>Two cell lines were derived from the tumor tissue of patients treated for glioblastoma multiforme. Nestin and other cytoskeletal proteins were visualized using imunocytochemical methods: indirect immunofluorescence and immunogold-labelling.</p> <p>Results</p> <p>Using epifluorescence and confocal microscopy, we described the morphology of nestin-positive intermediate filaments in glioblastoma cells of both primary cultures and the derived cell lines, as well as the reorganization of nestin during mitosis. Our most important result came through transmission electron microscopy and provided clear evidence that nestin is present in the cell nucleus.</p> <p>Conclusion</p> <p>Detailed information concerning the pattern of the nestin cytoskeleton in glioblastoma cell lines and especially the demonstration of nestin in the nucleus represent an important background for further studies of nestin re-expression in relationship to tumor malignancy and invasive potential.</p