Controlling food-contaminating fungi by targeting their antioxidative stress-response system with natural phenolic compounds

The antioxidative stress-response system is essential to fungi for tolerating exposure to phenolic compounds. We show how this system can be targeted to improve fungal control by using compounds that inhibit the fungal mitochondrial respiratory chain. Targeting mitochondrial superoxide dismutase with selected phenolic acid derivatives (e.g., vanillyl acetone) resulted in a 100- to 1,000-fold greater sensitivity to strobilurin or carboxin fungicides. This synergism is significantly greater with strobilurin than with carboxin, suggesting that complex III of the mitochondrial respiratory chain is a better target than complex II for fungal control, using phenolics. These results show certain natural compounds are effective synergists to commercial fungicides and can be used for improving control of food-contaminating pathogens. These results suggest that the use of such compounds for fungal control can reduce environmental and health risks associated with commercial fungicides, lower cost for control, and the probability for development of resistance.     

The Role of Visual Eccentricity on Preference for Abstract Symmetry

This study tested preference for abstract patterns, comparing random patterns to a two-fold bilateral symmetry. Stimuli were presented at random locations in the periphery. Preference for bilateral symmetry has been extensively studied in central vision, but evaluation at different locations had not been systematically investigated. Patterns were presented for 200 ms within a large circular region. On each trial participant changed fixation and were instructed to select any location. Eccentricity values were calculated a posteriori as the distance between ocular coordinates at pattern onset and coordinates for the centre of the pattern. Experiment 1 consisted of two Tasks. In Task 1, participants detected pattern regularity as fast as possible. In Task 2 they evaluated their liking for the pattern on a Likert-scale. Results from Task 1 revealed that with our parameters eccentricity did not affect symmetry detection. However, in Task 2, eccentricity predicted more negative evaluation of symmetry, but not random patterns. In Experiment 2 participants were either presented with symmetry or random patterns. Regularity was task-irrelevant in this task. Participants discriminated the proportion of black/white dots within the pattern and then evaluated their liking for the pattern. Even when only one type of regularity was presented and regularity was task-irrelevant, preference evaluation for symmetry decreased with increasing eccentricity, whereas eccentricity did not affect the evaluation of random patterns. We conclude that symmetry appreciation is higher for foveal presentation in a way not fully accounted for by sensitivity.     

Surfactin and fengycin lipopeptides of Bacillus subtilis as elicitors of induced systemic resistance in plants

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria that are responsible for the elicitation of the induced systemic resistance (ISR) phenomenon. This study shows that the lipopeptides surfactins and fengycins may be involved in this elicitation process. In bean, pure fengycins and surfactins provided a significant ISR-mediated protective effect on bean plants, similar to the one induced by living cells of the producing strain S499. Moreover, experiments conducted on bean and tomato plants showed that overexpression of both surfactin and fengycin biosynthetic genes in the naturally poor producer Bacillus subtilis strain 168 was associated with a significant increase in the potential of the derivatives to induce resistance. In tomato cells, key enzymes of the lipoxygenase pathway appeared to be activated in resistant plants following induction by lipopeptide overproducers. To our knowledge, such lipopeptides constitute a novel class of compounds from non-pathogenic bacteria that can be perceived by plant cells as signals to initiate defence mechanisms.     

Sequential metronidazole-furazolidone or clarithromycin-furazolidone compared to clarithromycin-based quadruple regimens for the eradication of Helicobacter pylori in peptic ulcer disease: a double-blind randomized controlled trial

Background: Furazolidone is a much cheaper drug with a very low resistance against Helicobacter pylori compared to clarithromycin. We aim to evaluate safety and efficacy of a sequential furazolidone‐based regimen versus clarithromycin‐based therapy in H. pylori eradication for ulcer disease. Materials: Patients with proven peptic ulcer or duodenitis were randomized into three groups: OAB‐M‐F; metronidazole (M) (500 mg bid) for the first 5 days, followed by furazolidone (F) (200 mg bid) for the second 5 days; OAC‐P; clarithromycin (C) (500 mg bid) for 10 days; and OAB‐C‐F; clarithromycin (500 mg bid) for the first 5 days and furazolidone (200 mg bid) for the second 5 days. All groups received omeprazole (O) (20 mg bid) and amoxicillin (A) (1 g bid). Groups OAB‐M‐F and OAB‐C‐F were also given bismuth subcitrate (B) (240 mg bid), whereas a placebo (P) was given to group OAC‐P. Adverse events were scored and recorded. Two months after treatment, a C¹³‐urea breath test was performed. Results: Three hundred and ten patients were enrolled and 92 (OAB‐M‐F), 95 (OAC‐P), and 98 (OAB‐C‐F) completed the study. The intention‐to‐treat eradication rates were 78.5% (95% CI = 69–85), 81.1% (95% CI = 73–88), and 82% (95% CI = 74–89), and per‐protocol eradication rates were 91.3% (95% CI = 83–96), 90.4% (95% CI = 82–95), and 88.7% (95% CI = 81–94), for group OAB‐M‐F, OAC‐P, and OAB‐C‐F, respectively. Eradication rate differences did not reach statistical significance. The most common adverse event, bad taste, occurred in all groups, but more frequently in groups OAC‐P (34%) and OAB‐C‐F (32%), than OAB‐M‐F (14%) (p < .05). Adverse symptoms score were 0.88 ± 2.05 in group OAB‐M‐F, 1.15 ± 1.40 in group OAC‐P, and 1.87 ± 1.62 in group OAB‐C‐F. Conclusion: Furazolidone can replace clarithromycin in H. pylori eradication regimens because of lack of development of resistance and very low cost.     

Aflatoxin contamination in different fractions of rice from Pakistan and estimation of dietary intakes

The purpose of this study was to determine the distribution of aflatoxins in rice milling fractions and to estimate dietary intakes. A total of 413 rice samples (paddy 58, parboiled 69, brown 84, white 93, and broken 109) were analyzed by HPLC with fluorescence detector. The results showed that 64?% paddy (16.35?±?1.67???g/kg), 38?% parboiled (14.20?±?2.04???g/kg), 33?% brown (9.85?±?1.25???g/kg), 42?% white (7.10?±?1.39???g/kg), and 50?% broken (8.5?±?1.71???g/kg) rice samples were contaminated with aflatoxins. It was found that paddy rice was most contaminated with aflatoxins while white rice was least contaminated. The percentage of samples exceeding EU maximum contents for total aflatoxins in rice (4???g/kg) varied from 14 to 36?% when compared to the analyzed rice fractions. The total estimated amount of aflatoxin intake for average rice consumers ranged from 19.1 to 26.6?ng/kg body weight/day, much higher than the reference value of 1?ng/kg body weight/day. This is the first report discovering that rice is a major contributor to the dietary intake of aflatoxins in Pakistan.     

Soil characteristics influence species composition and forest structure differentially among tree size classes in a Bornean heath forest

Plant and Soil - To investigate how different tree species affect the composition of SOM and its mineralization in boreal forest ecosystems. We used pyrolysis GC–MS for molecular-level...