Iron chelate inducible iron/manganese toxicity in zonal geranium

Leaf symptoms of a physiological disorder of cutting geranium (Pelargonium x hortorum L.H. Bailey ‘Aurora') were induced with FeDTPA treatments ranging from 0.02 mM (1 ppm) to 1.12 mM (60 ppm) applied to a soilless peat‐based medium. Symptoms included marginal/nterveinal chlorosis that progressed to marginalAnterveinal necrosis and in extreme cases whole leaf necrosis. Iron (Fe) concentration increased with increasing FeDTPA level in both symptom and asymptom tissues. Within the same FeDTPA treatments symptom tissue had higher concentration of Fe and manganese (Mn) than asymptom tissue. Manganese in symptom tissue decreased as FeDTPA level increased; whereas Mn concentration of asymptom tissue were similar among all FeDTPA treatments. Preplant addition of dolomite to maintain medium pH within the range of 5.8–6.2 lowered Fe and Mn concentration in both symptom and asymptom tissue and medium leachates; however, liquid dolomite drenches during the crop cycle had little effect on tissue Fe and Mn. This disorder results from increased levels of Fe and Mn in the plant tissue and should be referred to as Fe/Mn toxicity.     

Chronology of anthropogenic trace element input to four Utah lakes reconstructed using sediment cores

Trace element deposition chronologies are presented for radionuclide dated sediment cores collected from four Utah lakes. A core collected from Mirror Lake, a remote lake located in northern Utah, records a century long period of atmospheric deposition of anthropogenic Pb, Zn, Cu, Cd and Sn. Trace element concentration profiles in a core collected from Panguitch Lake, a remote lake located in southern Utah, give no indication of enhanced atmospheric deposition of trace elements in that part of the state. Sediment cores collected from Echo Reservoir and Deer Creek Reservoir, located near Salt Lake City, record releases of Pb, Zn, Cu, Cd, As, Sb, and Tl rich mine wastes into watershed streams from the now defunct Park City mining complex.     

ACCUMULATION OF SILICON IN CYNODON DACTYLON X C. TRANSVAALENSIS AND POA TRIVIALIS USED AS AN OVERSEED GRASS

Calcium silicate has been used to supply silicon (Si) as a plant nutrient for enhancing crop production and the suppression of turf diseases. Research was initiated to determine the effect of calcium silicate on silicon uptake, turf quality, and its residual activity in providing plant available Si in two turfgrass systems. During 2005 and 2006, calcium silicate (CaSi, 12% Si) was applied as a topdressing at eight rates ranging from 0 to 342 kg m^?2 to a ‘Tifdwarf’ (Cynodon dactylon × C. transvaalensis Burtt Davy) green in the spring and to the same plots overseeded with ‘Wintergreen’ rough bluegrass (Poa trivialis L.) in the fall. At initiation of the study, dolomitic limestone and magnesium sulfate (MgSO₄) was applied to equilibrate calcium across all treatments based on the highest rate of CaSi. Every 28 days, treatments were rated for turf quality and then harvested to determine Si accumulation. One month after applying CaSi in 2005, Si concentration in the leaf tissue of Tifdwarf had increased linearly with increasing rates. This response continued through the months of May, June, July, August, and October with a 9%, 21%, 40%, 22% and 21% increase in Si concentration in the leaf tissue between the control and the 342 kg m^?2 rate, respectively. Although the rate response remained, there was an overall drop in average percent Si accumulation in leaf tissue across the treatments beginning three months after the first application. Similar responses were noted with the overseeded rough bluegrass with a 46%, 85%, 69%, 111% and 58% increase in Si concentration in the leaf tissue between the control and the 342 kg m^?2 rate, respectively. In contrast to the bermudagrass, over the five month period following application, the residual activity of Si in rough bluegrass remained high, suggesting that rough bluegrass might be a better Si accumulator in comparison to Tifdwarf bermudagrass. The second run of the experiment (2006–2007) and the residual trial had the same response with Si concentration in the leaf tissue increasing as the amount of CaSi applied increased. Although turfgrass quality was not well correlated to CaSi rate for Tifdwarf bermudagrass, there was an increase in quality ratings for rough bluegrass from December 2005 to April 2006.     

Compost Research Runs “Hot” and “Cold” at La Trobe University

? Careful monitoring of the composting process — physically, chemically and biologically — enables managers to determine key nutritional and ecological factors vital to production of a quality compost. At La Trobe University, trials compared composts which achieve high temperature (80° C) with those controlled at moderate thermophilic temperatures (45 — 55° C) to demonstrate whether the hot phase is essential or whether composts of equal nutritional status can be produced by processing at lower temperatures.     

Profits and nitrate leaching under irrigated corn: a simulation

The economic impact of reducing the amount of nitrate leached out of the root zone under irrigation in the arid West was examined. The economic incentives of irrigation management were evaluated under the assumptions of both profit-maximizing and utility-maximizing (in reducing cost and effort expended in irrigation) decision-making criteria. The results indicate that there is a coincidence of interests of the farmer and the environment provided some leaching occurred. If no leaching is allowed, profit decreases markedly. Both behaviors result in less nitrate leaching than less profitable or less utility-producing irrigating practices.     

Effect of aluminum uptake on growth and enzyme activity in Pisum sativum var. ‘Alaska’ and ‘Little Marvel’

It is usually assumed that plant tissue responses to nutritional elements are due to specific genetic differences that may exist either between inbred or closely related species. Little Marvel (dwarf) and Alaska (normal) varieties of 14‐day old pea seedlings were treated with four different concentrations of Al‐containing nutrient solution (0.0mM, 0.2mM, 0.6mM and distilled H₂O), prior to being exposed for 14 days to either DARK, LIGHT, or UV. Selected tissues (root tip, main root, main stem and proximal stem) were bioassayed for peroxidase and polyphenol oxidase enzyme activities, fresh wt vs. dry wt, water uptake and stem growth. The present study suggests that Little Marvel and Alaska pea tissue responds to high toxicity levels of Al by demonstrating an enhancement of enzymic activity. Tissue weight, growth and water uptake also show differential tissue specificity in both Little Marvel and Alaska tissue, in terms of Al toxicity response, given a particular external exposure.     

Analysis of veterinary drugs and metabolites in milk using quadrupole time-of-flight liquid chromatography-mass spectrometry

A quadrupole time-of-flight (Q-TOF) liquid chromatography-mass spectrometry (LC-MS) method was developed to analyze veterinary drug residues in milk. Milk samples were extracted with acetonitrile. A molecular weight cutoff filter was the only cleanup step in the procedure. Initially, a set of target compounds (including representative sulfonamides, tetracyclines, β-lactams, and macrolides) was used for validation. Screening of residues was accomplished by collecting TOF (MS(1)) data and comparing the accurate mass and retention times of found compounds to a database containing information for veterinary drugs. The residues included in the study could be detected in samples fortified at the levels of concern with this procedure 97% of the time. Although the method was intended to be qualitative, an evaluation of the MS data indicated a linear response and acceptable recoveries for a majority of target compounds. In addition, MS/MS data were also generated for the [M + H](+) ions. Product ions for each compound were identified, and their mass accuracy was compared to theoretical values. Finally, incurred milk samples from cows dosed with veterinary drugs, including sulfamethazine, flunixin, cephapirin, or enrofloxacin, were analyzed with Q-TOF LC-MS. In addition to monitoring for the parent residues, several metabolites were detected in these samples by TOF. Proposed identification of these residues could be made by evaluating the MS and MS/MS data. For example, several plausible metabolites of enrofloxacin, some not previously observed in milk, are reported in this study.     

Effect of bread baking on the bioavailability of hydrogen-reduced iron powder added to unenriched refined wheat flour

Elemental iron powders are widely used to fortify flour and other cereal products. Our objective was to test the hypothesis that baking enhances the bioavailability of elemental iron powders by oxidizing Fe(0) to Fe(2+) or Fe(3+). An in vitro digestion/Caco-2 cell culture model and a piglet model were used to measure bioavailability. Bread flour, either unfortified or fortified with hydrogen-reduced (HR) iron powder or FeSO(4) (300 mg Fe/kg flour), was baked into bread. For the in vitro studies, bread samples were treated with pepsin at pH 2, 3, 4, 5, 6, or 7 and subsequently incubated with pancreatic enzymes at pH 7 in a chamber positioned above monolayers of cultured Caco-2 cells. Ferritin formation in the cells was used as an index of iron bioavailability. Ferritin formation in cells fed HR Fe bread was similar to cells fed FeSO(4) bread when the peptic digestion was conducted at a pH 2 but lower when the peptic phase was conducted at pH 3, 4, 5, 6, or 7 (P < 0.05). Pig diets containing 35% dried bread were prepared and fed to cross-bred (Hampshire x Landrace x Yorkshire) anemic pigs in two studies. The rate of increase in hemoglobin Fe over the feeding period was used to calculate relative biological value (RBV), an index of iron bioavailability. In the first pig study, RBV of HR Fe added to flour prior to baking was 47.9% when compared to FeSO(4) fortified flour (P < 0.05). In the second pig study, a third treatment consisting of unfortified bread with HR iron added during diet mixing (after bread baking) was included. RBVs of the HR Fe diet (Fe added after baking) and HR Fe diet (Fe added before baking) were 40.1% and 53.5%, respectively, compared to the FeSO(4) diet. Differences in RBV between the HR Fe (before and after baking) and FeSO(4) (before baking) treatment groups were significant, but the difference between the before and after HR treatment groups was not significant. We conclude that bread baking does not enhance the bioavailability of elemental iron powders.     

Modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (abts) method to measure antioxidant capacity of Selected small fruits and comparison to ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods

The measurement of antioxidant capacity in fruits differs from that of other biological samples due to their low pH and very low lipophilic antioxidant capacity. In this report, we present a modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method for fruits and compare its performance with the other commonly used antioxidant methods of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The antioxidant capacity and reaction kinetics of four phenolic compounds, two antioxidant standards, and five fruits were also investigated. The modified ABTS method prepared at a pH of 4.5 with sodium acetate buffer is highly stable and easily applied to fruit samples as compared to the standard (pH 7.4) version. The measured antioxidant capacity of samples varied with the assay method used, pH, and time of reaction. Traditional antioxidant standards (trolox, ascorbic acid) displayed stable, simple reaction kinetics, which allowed end point analysis with all of assays. Of the phenolic compounds examined, chlorogenic and caffeic acids exhibited the most complex reaction kinetics and reaction rates that precluded end point analysis while gallic acid and quercetin reached stable end points. All fruit extracts exhibited complex and varied kinetics and required long reaction times to approach an end point. Because the antioxidant capacity of fruit extracts is a function of the array of individual antioxidants present, accurate comparisons among fruit samples require that reaction times be standardized and of sufficient length to reach steady state conditions and that more than one assay be used to describe the total antioxidant activity of fruit samples.     

Enzyme-linked immunosorbent assay for screening aflatoxin B1 in cottonseed products and mixed feed: collaborative study

A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, South Africa, Switzerland, The Netherlands, Tunisia, and the United States. Twenty-eight samples of raw and roasted peanuts, corn, whole cottonseed, cottonseed meal, ammoniated cottonseed meal, and poultry feed containing various quantities of natural aflatoxins and supplemented when appropriate with aflatoxin B1 were distributed to participating laboratories for testing. The assay is based on conjugation of pure aflatoxin B1 to an enzyme and the competition between this conjugate and (free) aflatoxins in the product for aflatoxin-specific antibodies coated onto microtiter well walls. After a wash step to remove all unbound aflatoxins, a substrate, added to each well, is catalyzed from a colorless to a green solution by any bound enzyme-conjugated aflatoxin B1 present. The intensity of the color decreases as the amount of free aflatoxin B1 in the product increases. Overall correlation was good between ELISA and thin-layer chromatographic (TLC) results for cottonseed products and mixed feed. Variable results were reported for corn and peanut product samples. Although some positive samples (greater than 15 ng/g) of cottonseed products and mixed feed were reported to contain less than 15 ng/g by visual determination, a review of data for absorbance measurements showed that the contamination level was close to the greater than or equal to 15 ng/g standard and would not have been reported as negative under routine screening.(ABSTRACT TRUNCATED AT 250 WORDS)