Comparative analysis of the effects of locally used herbicides and their active ingredients on a wild-type wine Saccharomyces cerevisiae strain

Herbicides are released to the environment with potential ecotoxicological risks for mammals. Yeast is a good model to elucidate toxicity mechanisms. We investigated how three commercial herbicides (Proper Energy, Pointer, and Silglif) and their active ingredients (respectively, fenoxaprop-P-ethyl, tribenuron methyl, and glyphosate) can affect biological activities of an oenological Saccharomyces cerevisiae strain, which may be resident on grape vineyards of the same geographical areas where herbicides are used. The use of commercial grade herbicides employed in Italy allowed us to reproduce the same conditions applied in crops; at the same time, assaying pure single active compounds made it possible to compare the effects obtained with commercial formulations. Interestingly, we found that while pure active compounds affect cell growth and metabolism at a lower extent, commercial preparations have a significant major negative influence on yeast biology.     

Improved HPLC determination of phenolic compounds in cv. golden delicious apples using a monolithic column

A rapid HPLC-DAD determination of phenols in apple using an RP monolithic column is reported. Because of the hydrodynamic advantages offered by this kind of column and the use of acidified acetonitrile as eluent, assays of apple extracts can be performed in <21 min. Assays of pulp and peel extracts were carried out without the need for time-consuming sample pretreatment except filtration. Several flavanols, hydroxycinnamic acids, dihydrochalcones, and six quercetin glycosides were identified and quantified. A seventh quercetin derivative, two chalcone-related compounds, and three hydroxycinnamic derivatives were also found. Peels proved to be richer in phenols than pulps, the former being composed mainly of (-)-epicatechin, procyanidin B2, chlorogenic acid, phloridzin, hyperin, and avicularin. In pulps, where the chlorogenic acid was the principal phenolic compound, quercetin glycosides were found in very low amounts.     

Eating at fast-food restaurants is associated with dietary intake, demographic, psychosocial and behavioural factors among African Americans in North Carolina

OBJECTIVE: To examine associations of the frequency of eating at fast-food restaurants with demographic, behavioural and psychosocial factors and dietary intake in African American adults. METHODS: Self-reported data from a population-based cross-sectional survey of 658 African Americans, aged 20-70 years, in North Carolina. An 11-page questionnaire assessed eating at fast-food restaurants, demographic, behavioural and diet-related psychosocial factors, and dietary intake (fruit, vegetable, total fat and saturated fat intakes, and fat-related dietary behaviours). RESULTS: The participants were aged 43.9+/-11.6 years (mean+/-standard deviation), 41% were male, 37% were college graduates and 75% were overweight or obese. Seventy-six per cent reported eating at fast-food restaurants during the previous 3 months: 4% usually, 22% often and 50% sometimes. Frequency of eating at fast-food restaurants was positively associated with total fat and saturated fat intakes and fat-related dietary behaviours (P<0.0001) and inversely associated with vegetable intake (P<0.05). For example, mean daily fat intake was 39.0 g for usually/often respondents and 28.3 g for those reporting rare/never eating at fast-food restaurants. Participants who reported usual/often eating at fast-food restaurants were younger, never married, obese, physically inactive and multivitamin non-users (all P<0.01). Frequency of eating at fast-food restaurants was positively associated with fair/poor self-rated health, weak belief in a diet-cancer relationship, low self-efficacy for healthy eating, weight dissatisfaction, and perceived difficulties of preparing healthy meals and ordering healthy foods in restaurants (all P<0.05). Frequency of eating at fast-food restaurants did not differ significantly by sex, education, smoking, ability to purchase healthy foods or knowledge of the Food Guide Pyramid. CONCLUSIONS: Eating at fast-food restaurants is associated with higher fat and lower vegetable intakes in African Americans. Interventions to reduce fast-food consumption and obesity in African Americans should consider demographic and behavioural characteristics and address attitudes about diet-disease relationships and convenience barriers to healthy eating.     

Phytotoxins from the leaves of Ruta graveolens

Bioassay-guided fractionation of the ethyl acetate extract of Ruta graveolens (common rue) leaves led to the isolation of the furanocoumarins 5-methoxypsoralen (5-MOP), 8-methoxypsoralen (8-MOP), and the quinolone alkaloid graveoline as phytotoxic constituents. Graveoline and 8-MOP substantially inhibited growth of Lactuca sativa (lettuce) seedlings and reduced chlorophyll content at 100 microM; this effect was not due to a direct effect on chlorophyll synthesis. Radical growth of L. sativa was inhibited by 10 microM 8-MOP. Graveoline inhibited growth of Lemna paucicostata (duckweed) at 100 microM. This is the first report of the phytotoxic activity of graveoline. Growth of Agrostis stolonifera (bentgrass) was inhibited by 5-MOP at 30 microM. All three compounds substantially reduced cell division in Allium cepa (onion) at or below 100 microM. None of the compounds caused significant cellular leakage of Cucumis sativus (cucumber) cotyledon disks at 100 microM. All three compounds inhibit plant growth, at least partially through inhibition of cell division.     

Sources and distribution of arsenic in the aberjona watershed,eastern Massachusetts

Significantly elevated concentrations of arsenic have been found in soils and in riverine and lacustrine sediments in the Aberjona watershed in eastern Massachusetts. From available data we estimate that on the order of 300 metric tons of arsenic are present in contaminated areas of the watershed. The presence of arsenic and other contaminants in industrial areas and at disposal sites in the watershed has led to the designation of two federal and over 20 state hazardous waste sites. Historical records indicate that much of the arsenic in this watershed was generated as a by-product of sulfuric acid and arsenical pesticide manufacturing between 1888 and 1929. By using pesticide and sulfuric acid manufacturing data, as well as historical information on manufacturing techniques and rates of waste generation, we estimate that on the order of 200 to 900 metric tons of arsenic were released as a result of these activities. A significant fraction, approximately 13 metric tons, is believed to have been transported by the Aberjona River from a chemical manufacturing site to the Mystic Lakes 10 km downstream.     

Bioavailability of cadmium from in vitro digested infant food studied in Caco-2 cells

The solubility and bioavailability of cadmium (Cd) in infant foods, three cereal- and milk-based diets and two ready-to-use baby dishes, were studied after in vitro digestion and by using human intestinal Caco-2 cells. The solubility of Cd after in vitro digestion varied between diets; liver casserole had the highest solubility and was lower after infant as compared to adult digestion conditions. Generally, more Cd was soluble in infant intestinal than gastric juice in contrast to the results from the adult digestion. Caco-2 cells were incubated with supernatants of infant digests that had been equilibrated with (109)Cd during the in vitro digestion procedure, and cellular uptake and transport of (109)Cd were measured after 180 min. Statistically significant differences in both uptake and transport of Cd were detected between some of the diets and a control solution containing only digestive enzymes and (109)CdCl(2). Uptake of soluble Cd in the cells varied between diets from 4 to 6%, and the transport over the monolayers was 1-2% of the dose. We conclude that age specific digestion conditions as well as composition of diets affect both solubility and bioavailability of Cd.     

A field assessment of the role of selective herbicides in the restoration of British moorland dominated by Molinia

Upland heather moors are high priority biotopes for conservation in Britain, but are under threat from a number of sources. One such threat is a change from a vegetation dominated by dwarf shrubs, mainly Calluna vulgaris, to a grassland dominated by Molinia caerulea. Restoration of a dwarf shrub community has proved problematic with studies showing that herbicide use may be necessary to control Molinia. Previously the non-selective herbicide, glyphosate, has been recommended, but this herbicide may damage Calluna and other moorland species severely. Here, we tested a range of selective herbicides (graminicides) for use in an herbicide-based conservation strategy under field conditions. Two selective herbicides, propaquizafop and quizalofop-ethyl, gave a short-term check to Molinia and another, cycloxydim, provided a reduction for at least 1 year, but this effect disappeared after 3 years. Damage to Calluna was less than that caused by glyphosate, and the selective herbicides had little effect on other moorland species present. Our findings suggest that selective herbicides have a potential role in reducing Molinia during moorland restoration, although follow-up applications, and appropriate moorland management, will also be needed.     

Relationship of soil properties to pyroxasulfone bioactivity in a range of prairie soils

The relationship between pyroxasulfone bioactivity and soil properties has not been investigated in a wide range of soils typical of western Canada. In this study, 47 soils from Saskatchewan, Manitoba and Alberta, with varying organic matter content (1.5%–22.1%), pH (5.0–7.9), and clay content (6.8%–59.4%) were used to evaluate the effect of soil properties on pyroxasulfone bioactivity and its relevance to field application rates. Bioactivity was assessed by measuring the reduction of sugar beet shoot length after 7 days in response to 0, 92, 184, and 368 µg?ai?kg^?1 pyroxasulfone concentration in soil. Multiple regression analysis showed that pyroxasulfone bioactivity was related to soil organic matter content, pH and clay content. Grouping the soils according to these properties allowed for a summarization of pyroxasulfone field application rates required to achieve bioactivity based on the magnitude of sugar beet shoot length inhibition (%). The estimated field application rates ranged from less than 120–480 g?ai?ha^?1.     

In Vitro Studies on Atrazine Effects on Human Intestinal Cells

Considering the importance of the oral route for human exposure to atrazine, we have investigated the possible effect of this herbicide on the human intestinal cells and the integrity of the epithelial barrier, using Caco-2 cells as the intestinal model in vitro. We evaluated possibile cytotoxic and genotoxic effects of atrazine in concentrations ranging from 1 to 250 μM on the Caco-2 cells at different stages of growth after short- and long-term exposure. Results from the tetrazolium blue (MTT) test and the Trypan blue exclusion assay showed that atrazine cytotoxicity was dose- and time-dependent. Obtained data indicated that atrazine at high concentrations (50 and 250 μM) was able to induce effects on Caco-2 proliferation and viability. Moreover, it was found that the long-term exposure to atrazine at the non-cytotoxic dose caused inhibition of the intestinal cell maturation and decreased the transepithelial electrical resistance, the indicator of the epithelial barrier integrity. Studies on the atrazine genotoxicity determined using the single cell microelectrophoresis assay indicated that atrazine did not induce DNA damages in the Caco-2 cells at concentrations of up to 50 μM, whereas enhancement in the DNA damage was observed at 250 μM. Altogether, our results indicate that atrazine at expected human oral exposure concentrations is not able to induce effects on the Caco-2 cell proliferation and viability, but may suppress the intestinal cell differentiation and reduce the cell monolayer integrity. We suggest that chronic exposure on low levels of atrazine may lead to alteration in the expression of the morphological and functional features of the Caco-2 cells related to the transport and barrier function of small intestinal enterocytes. In consequence, this may lead to alterations in the intestinal absorption process.     

Modeling regional-scale habitat of forest birds when land management guidelines are needed but information is limited

Conservation planning at broad spatial scales facilitates coherence between local land management and objectives set at the state or provincial level. Habitat suitability models are commonly used to identify key areas for conservation planning. The challenge is that habitat suitability models are data hungry, which limits their applicability to species for which detailed information exists, but managers need to address the needs of all at-risk species. We propose a modeling approach useful for regional-scale conservation planning that accommodates limited species knowledge, and identifies what managers should aim for at the local scale. For twenty at-risk bird species, we built models to identify potential habitat using both literature information and empirical data. Species occupancy within potential habitat depends on the presence of intrinsic elements, which we identified for each species so that managers can enhance these elements as appropriate. For most species, the estimated amount of habitat needed to meet population targets was <10% of the mapped potential habitat, with notable exceptions for Northern Goshawk (Accipiter gentilis; 100%), Brown Thrasher (Toxostoma rufum; 63.7%), and Veery (Catharus fuscescens; 17.9%). Model validation showed that interior forest species models performed best. Our modeling framework allowed us to build potential habitat models to various endpoints for different species, depending on the information available, and revealed a number of species for which basic natural history data are missing. Our potential habitat models provide regional perspective and guide local habitat management, and assist in identifying research priorities.