Detection and characterization of DNA adducts formed from metabolites of the fungicide ortho-phenylphenol

The significance of DNA adduction in ortho-phenylphenol-induced carcinogenesis remains unclear. Establishing adduct structures may contribute to resolving this issue. The chemical structures of the DNA adduction products resulting from the in vitro reaction of phenylbenzoquinone, the putative ultimate carcinogenic metabolite of the fungicide/disinfectant ortho-phenylphenol, are reported here. Three isomeric adducts that resulted from reaction of deoxyguanosine were characterized by UV, LC-ESI-MS, and MS/MS, and 1D and 2D COSY-NMR spectroscopy. The proposed mechanism of product formation is nucleophilic attack by the deoxyguanosine exocyclic amine nitrogen on an electrophilic quinone carbon, followed by stabilization through enolization. Another nucleophilic attack forms a five-membered ring, which aromatizes by dehydration to form the final product. Adducts were also characterized from deoxyadenosine and deoxycytidine, although conversions were at least 10 times lower. Structures are also proposed for these products. Cell culture studies confirmed that HepG2 cells incubated with phenylbenzoquinone at concentrations associated with cytotoxicity form the same DNA adducts.     

Soil management options for Alfisols in the semi-arid tropics: annual and perennial crop production

A field experiment was conducted in the semi arid tropics to study the effects of soil structural modification on cropping systems. The aim was to improve crop production and land resource protection using innovative soil management practices. Tillage, mulch and perennial/annual rotational based systems were compared for 5 years in an Alfisol at ICRISAT in India. Crop yield parameters, including grain and biomass yield, leaf area index, crop cover, and plant height were measured. Results indicate significant benefits to annual crop yield (maize, sorghum) from improved water supply due to mulching with farmyard manure or and rice straw, and due to rotation with prior-perennial crops. Grain yields were 16 to 59% higher in mulched treatments compared to unmulched treatments, with similar increases for fodder yields. Annual crop yields after 4 years of perennials were 14 to 81% higher than unmulched treatments, except for low fertility maize grown after buffel grass. The interaction with chemical fertility was less clear than for water supply. The results have implications for soil management throughout the semi-arid tropics.     

Sheld-geese and man in the Falkland Islands

The history of the association between sheld-geese (upland geese Chloëphaga picta and ruddy-headed geese C. rubidiceps) and man in the Falkland Islands is described from the time when they were used as food by early settlers, to the conflict with the sheep industry. Geese were found to be extremely abundant when man first settled. A bounty scheme was instigated by sheep farmers in 1905 and claimed 74 000 geese annually between 1905 and 1912. Far fewer (25 000 annually) were killed in the late 1970s because fewer shepherds lived in the remote houses of sheep stations, and the bounty did not increase in proportion with wage increases. The population of geese remains large despite this toll and recent studies of the annual cycle, movements and population dynamics give reasons for the failure of the bounty scheme to reduce numbers. Information on food intake and densities of geese on different vegetation types has indicated that the geese populations take only 1·5% of the total annual organic matter production of herbage. This represents 7% of what is eaten by all the herbivores. However, most of this consumption is restricted to a few vegetation types with a relatively small area (e.g. ‘greens’ and reseeded pastures). It is the consumption from reseeds that causes the biggest problem to the sheep industry. Methods of control are discussed and the value of destruction of geese questioned.     

Applying combinatorial chemistry and biology to food research

In the past decade combinatorial chemistry has become a major focus of research activity in the pharmaceutical industry for accelerating the development of novel therapeutic compounds. The same combinatorial strategies could be applied to a broad spectrum of areas in agricultural and food research, including food safety and nutrition, development of product ingredients, and processing and conversion of natural products. In contrast to "rational design", the combinatorial approach relies on molecular diversity and high-throughput screening. The capability of exploring the structural and functional limits of a vast population of diverse chemical and biochemical molecules makes it possible to expedite the creation and isolation of compounds of desirable and useful properties. Several studies in recent years have demonstrated the utility of combinatorial methods for food research. These include the discovery of synthetic antimicrobial, antioxidative, and aflatoxin-binding peptides, the identification and analysis of unique flavor compounds, the generation of new enzyme inhibitors, the development of therapeutic antibodies for botulinum neurotoxins, the synthesis of unnatural polyketides and carotenoids, and the modification of food enzymes with novel properties. The results of such activities could open a large area of applications with potential benefits to the food industry. This review describes the current techniques of combinatorial chemistry and their applications, with emphasis on examples in food science research.     

Prioritization of ground water contaminants and sources

The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their health concerns. The developed contaminant prioritization methodology was based on frequency of occurrence and adverse health effects. Adverse health effects were based on carcinogenic potency, toxicity, hazardous chemical priorities and drinking water standards. Application of the methodology for wellhead protection areas, (WHPAs) revealed that approximately 200 different contaminants have been detected in the nation's public ground water supplies. The seven chemical constituents with the highest priority were arsenic, chromium, cadmium, carbon tetrachloride, chloroform, 1, 1-dichloroethylene, and ethylene dibromide. Other contaminants of concern were trichloroethylene, nitrates, barium, 1,1,1-trichloroethane, benzene, tetrachloroethylene, selenium, lead, toluene, mercury, gross alpha radiation, methylene chloride, coliform bacteria, metolachlor, metribuzin, 1, 1, 2, 2-tetrachloroethane, dibromochloroethane, simazine, radium-266, and toxaphene. The contaminant source prioritization methodology was also based on frequency of occurrence. Over 30 categories of sources were evaluated, with the eight with highest priority including agricultural activities, hazardous waste sites, landfills, industrial operations, septic tank systems, oil and gas field activities, urban land use, and underground storage tanks.     

Freshwater conservation planning in data-poor areas: An example from a remote Amazonian basin (Madre de Dios River, Peru and Bolivia)

Using the 160,000-km² drainage basin of the Madre de Dios and Orthon rivers in the southwest Amazon as a test case, we piloted an approach for large-scale conservation planning for freshwater systems characterized by a near-complete lack of biological and physical data. We used newly available spatial and remote sensing datasets, including spaceborne optical and radar observations, and new techniques of spatial data analysis to generate subbasin (?100 km²), stream, and floodplain and wetland habitat classifications. We then generated a preliminary plan for a network of conservation areas to protect the most intact examples of representative habitat types while maximizing longitudinal and lateral connectivity. Proposed additions for freshwater conservation complement existing reserves and build on earlier conservation planning efforts for terrestrial ecosystems. In the resulting integrated plan, at least 20% of the area of each major freshwater habitat type is represented and two continuous corridors exist from the mouth of the Madre de Dios to its headwaters in the Andes. In total, we highlighted 84 currently unprotected subbasins to fulfill our representation and connectivity goals. About two-thirds of these subbasins were considered relatively undisturbed and are identified as Level I (critical management zones) or Level II (indigenous territories), whereas one-third are potentially degraded and thus were designated as Level III (threat mitigation zones). This exercise provides an example of how newly available remote-sensing datasets and analytical tools may be used to advance freshwater conservation planning, particularly in data-poor regions.     

Spatial Relations between Row Crops and Nitrate Contamination in Groundwater

Nitrogen management practices associated with row crops arewidely considered as an important contributor to nitrate pollution in water resources. We studied the relations between row crops and nitrate concentration in groundwater in an agricultural basin of Iowa, U.S.A., from a spatial perspective. Nitrate concentration and row crop area wereanalyzed on a section scale (a square mile, or 2.56 km²)for three different years. Their section values were standardized to remove the effects of precipitation and non-constant sample variances in different years. The between-year differences in individual section values werecollectively analyzed as an indication of changes in the spatial distribution from year to year. Contingency table analysis was applied to test for relations of spatial changesbetween nitrate and row crops. During the study period, thenitrate concentration and row crop area on a per section basischanged considerably from one sampling year to another.However, no significant changes were found in their spatial distributions. As a result, no significant relations betweennitrate and row crops were found in terms of changes in theirspatial distributions.     

alpha-Naphthoflavone, a potent antiplatelet flavonoid, is mediated through inhibition of phospholipase C activity and stimulation of cyclic GMP formation

The aim of this study was to systematically examine the inhibitory mechanisms of the flavonoid alpha-naphthoflavone (alpha-NF) in platelet activation. In this study, alpha-NF concentration dependently (5-20 microM) inhibited platelet aggregation stimulated by agonists. alpha-NF (5 and 10 microM) inhibited intracellular Ca(2+) mobilization, phosphoinositide breakdown, and thromboxane A(2) formation stimulated by collagen (1 microg/mL) in human platelets. In addition, alpha-NF (5 and 10 microM) markedly increased levels of cyclic GMP and cyclic GMP-induced vasodilator-stimulated phosphoprotein (VASP) Ser(157) phosphorylation. Rapid phosphorylation of a platelet protein of Mr 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (60 nM). This phosphorylation was markedly inhibited by alpha-NF (5 and 10 microM). However, alpha-NF (5 and 10 microM) did not reduce the electron spin resonance (ESR) signal intensity of hydroxyl radicals in collagen (1 microg/mL)-activated platelets. These results indicate that the antiplatelet activity of alpha-NF may be involved in the following pathways. (1) alpha-NF may inhibit the activation of phospholipase C, followed by inhibition of phosphoinositide breakdown, protein kinase C activation, and thromboxane A(2) formation, thereby leading to inhibition of intracellular Ca(2+) mobilization. (2) alpha-NF also activated the formation of cyclic GMP, resulting in inhibition of platelet aggregation. These results strongly indicate that alpha-NF appears to represent a novel and potent antiplatelet agent for treatment of arterial thromboembolism.     

Effects of marine reef National Parks on fishery CPUE in coastal Kenya

The role of marine protected areas in conserving fish stocks and their potential influence on adjacent fisheries was studied at Malindi and Watamu Marine National Parks, Kenya (established in 1968). For most species catch per unit effort (CPUE) in traditional Dema traps fished across park boundaries was higher within the parks (up to an order of magnitude). However, a few species (e.g., the seagrass parrotfish, Leptoscarus vaigensis and the whitespotted rabbitfish, Siganus sutor, WSR) had higher seasonal CPUE outside the parks. Potential spillover of fishes from the parks to adjacent fished areas was tested with a logistic “decay” model of density gradients (CPUE) across park borders from fringing and patch reefs. A steep decay in CPUE off the Malindi patch reef suggested little spillover of most species. However, greater spillover was suggested off fringing reefs. Species differences were evident. The two most important commercial species showed different density gradients. Species diversity declined more abruptly off the fringing reefs. We conclude that although spillover of most species from the parks is limited, the most important commercial species exhibits significant spillover to adjacent fisheries and the Parks likely comprise important nursery and growth areas for other species.     

Acidification of surface waters in two areas of the Eastern United States

Acidification by precipitation of undisturbed, upland surface waters was examined in the White Mountains of New Hampshire and the Blue Ridge Mountains of North Carolina. The pH and alkalinity of samples taken in the summer of 1979 were compared to those taken in North Carolina in the early 1960s and in New Hampshire in the late 1930s. These parameters had declined significantly over the sampling intervals. Results were confirmed by comparing recent measurements of Ca, Mg, Na, and K to those of bicarbonate alkalinity. This comparison confirmed the hypothesis that some acidification has occurred in both areas and that acidification was more pronounced in the New Hampshire waters.