Iron chelation by the powerful antioxidant flavonoid quercetin

Chelation of the bare and hydrated iron(II) cation by quercetin has been investigated at the DF/B3LYP level in the gas phase. Several complexed species arising from neutral and anionic forms of the ligand have been taken into account. Both 1:1 and 1:2 metal/flavonoid stoichiometries have been considered. Results indicate that among the potential sites of chelation present on quercetin, the oxygen atoms belonging to the 3-hydroxy and 4-oxo, and to the 5-hydroxy and 4-oxo groups, are the preferred ones. Time-dependent density functional theory (TDDFT) calculations, used to reproduce the electronic UV-vis spectra of isolated quercetin and its complexes with Fe2+, were also performed in methanol and dimethylsulfoxide.     

Isolation and biochemical characterization of a basic myrosinase from ripe Crambe abyssinica seeds,highly specific for epi-progoitrin

On the basis of previous studies on the mechanism-based inhibition, activation, and active site structure of myrosinase(s) isolated from Sinapis alba and other cruciferous seeds, crambe myrosinase shows uncommon properties and behavior. For this reason homogeneous crambe myrosinase was isolated and investigated to establish the most important physicochemical features, including kinetic properties determined with the epimers progoitrin (R) and epi-progoitrin (S) as substrates, with and without ascorbate as an activator. The results of this study demonstrate that crambe myrosinase is highly specific for epi-progoitrin due to a better stabilization of the enzyme-substrate complex. This stabilization is caused by additional hydrogen bonding that only epi-progoitrin can set up between its hydroxyl group and a suitable residue in the hydrophobic pocket where the "docking" of the glucosinolates side chain takes place.     

Extractable iron and organic matter in the suspended insoluble material of fog droplets

In this work the formation and composition of aggregates between metals and organic material is studied in real fog samples. In a preliminary experiment it has been found that concentrated cloud samples form a yellow-brown precipitate in the presence of Fe(III). Standards of humic acids and fulvic acids co-precipitate with Fe(III), forming similar aggregates i.e. iron-humates (Fe-HA) and iron-fulvates (Fe-FA). By comparing the solubility properties of aggregates by extracting organic carbon (OC) in different pH conditions, it has been observed that fog droplet particulate samples are characterised by solubility properties more similar to those of Fe-HA than Fe-FA. Dilute alkaline solutions can also easily extract organic refractory substances that form aggregates with metals. The recoveries of the total extractable organic matter (accounting for 12% of total insoluble carbon and 15% of particulate mass) are similar to those of humic-like substances (HULIS) from particulate samples. The chromatographic behaviour and functional group characteristics measured in the alkali-extract fraction of precipitated aggregates with iron and in the insoluble particulate of fog samples, are those of humic-like material. Thus, soluble HULIS are able to interact with iron to form particulate, but the composition of a large fraction of insoluble organic carbon is still unknown. These findings have implications on the solubility and surface tension properties of fog droplets and can therefore potentially influence droplet formation, as well as cloud chemical and photochemical processes.     

Hunger and health among undocumented Mexican migrants in a US urban area

OBJECTIVES: To measure the occurrence and correlates of hunger and to evaluate the association between hunger and three health indicators among undocumented Mexican immigrants. DESIGN: Non-probability cross-sectional sample. SETTING: Neighbourhoods within New York City. SUBJECTS: Four hundred and thirty-one undocumented Mexican immigrants living in the USA. RESULTS: Hunger was indicated by approximately 28% of respondents. In a multivariate model, working as a day labourer was associated with hunger (odds ratio (OR) 3.33, 95% confidence interval (CI) 1.83-6.06) while receiving public assistance protected against hunger (OR 0.23, 95% CI 0.06-0.88). In multivariate models, respondents who reported experiencing hunger also reported poorer overall health (OR 1.69, 95% CI 0.95-3.02) and more days of poor mental (P = 0.045) and physical health (P < 0.0001). Greater amount of time lived in the USA was also associated with worse overall health (P = 0.054) and more days of poor mental and physical health (P < 0.01). CONCLUSIONS: The present study shows that food insecurity and hunger may be problems among undocumented migrants living in the USA. Uncertain and unpredictable work schedules and limited access to public assistance may contribute to high levels of hunger, which in turn may also negatively affect mental and physical health. Increasing amount of time lived in the USA is also associated with poorer health indicators. Programmes that provide undocumented migrants with emergency access to resources may reduce food insecurity and lead to improved health outcomes among this vulnerable population.     

Use of reverse micelles for the simultaneous extraction of oil, proteins, and glucosinolates from cruciferous oilseeds

Cruciferous oilseeds are important sources of oil, proteins, and glucosinolates (GLs), potentially available when biorefinery processes are used. The proposed extraction technology is based on the use of reverse micelles (RMs) made with cetyltrimethylammonium bromide (CTAB) dispersed in organic solvent. The physicochemical properties of this extraction system and the good water solubility of many high value compounds, such as GLs and some proteins, permit the simultaneous extraction of oil, and these products from cruciferous oilseed meals. This procedure is based on three main steps: (i) seed conditioning; (ii) solid-liquid extraction by RM solution; and (iii) back-transfer of the RM solution for recovery of the extracted compounds. The method makes it possible to simultaneously extract almost the same amount of oil as with pure organic solvents used in the current extraction plants and more than 90% of soluble proteins and GLs. It is a promising biorefinery technology alternative to traditional oil extraction processes.     

Chemical composition of the essential oils of Juniperus from ripe and unripe berries and leaves and their antimicrobial activity

The composition of the essential oil from ripe and unripe berries and leaves of Juniperus oxycedrus L. ssp. oxycedrus, Juniperus phoenicea ssp. turbinata and Juniperus communis ssp. communis was analyzed by GC-MS, and microbiological assays were carried out. Samples were collected in different localities (Sardinia, Italy) and hydro distilled. The yields ranged between 2.54% +/- 0.21 (v\w dried weight) and 0.04% +/- 0.00. A total of 36 components were identified. The major compounds in the essential oils were alpha-pinene, beta-pinene, delta-3-carene, sabinene, myrcene, beta-phellandrene, limonene, and D-germacrene. Both qualitative and quantitative differences between species and between different parts of the plant were observed. The essential oils and their major compounds were tested against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the minimum inhibitory concentration and minimum bactericidal concentration were determined. The results obtained led to a nonsignificant inhibitory effect, although all the essential oils from Juniperus phoenicea ssp. turbinata and the essential oil from leaves of Juniperus oxycedrus ssp. oxycedrus exhibited rather good or weak activity against Candida albicans and Staphylococcus aureus.     

Survey onYersinia Enterocolitica and related bacteria in shellfish

Results from examining shellfish collected from ‘safe’ (2–34Escherichia coli/100 mL) and ‘unsafe’ (> 34E. coli/100 mL) waters for the presence ofYersinia enterocolitica and related bacteria are reported. The recovery of these microorganisms was low in bivalve mollusks destined for food consumption, high in those derived from prohibited areas. No human pathogenic bio-serogroup f Yersinia was found during the entire survey.     

The vertical distribution of the Cs-137 derived from Chernobyl fall-out in the uppermostSphagnum layer of two peatlands in the southern Alps (Italy)

The patterns of concentration of the Cs-137 derived from the Chernobyl accident were analysed in a series of vertical profiles ofSphagnum collected at two peatlands in the southern Alps. The peak concentrations of the Chernobyl radiocesium were found in segments ofSphagnum located at different distances from the growing apex, probably corresponding to the plant tissues produced in the 1986 vegetation season. This indicated that the growth rates ofSphagnum are subject to considerable variations not only between species, but also between years and even between individuals of the same species when growing in different microhabitats at the same site. However, the concentrations of the Chernobyl-derived radiocesium are high also in theSphagnum segments produced after 1986. This was due to a continuous translocation of Cs-137 towards the capitulum, probably determined by the chemical similarity between cesium and potassium. Although the two sites investigated received nearly the same amounts of rainfall in the two-week period following the arrival of the Chernobyl plume, the average concentrations of radiocesium in allSphagnum species were significantly higher at one of them, presumably because the fall-out deposition was conditioned by a number of meteorological factors besides precipitation.