Speciation of arsenic in different types of nuts by ion chromatography-inductively coupled plasma mass spectrometry

In this work the quantitative determination and analytical speciation of arsenic were undertaken in different types of nuts, randomly purchased from local markets. The hardness of the whole nuts and high lipid content made the preparation of this material difficult for analysis. The lack of sample homogeneity caused irreproducible results. To improve the precision of analysis, arsenic was determined separately in nut oil and in the defatted sample. The lipids were extracted from the ground sample with the two portions of a mixture of chloroform and methanol (2:1). The defatted material was dried and ground again, yielding a fine powder. The nut oil was obtained by combining the two organic extracts and by evaporating the solvents. The two nut fractions were microwave digested, and total arsenic was determined by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained for oils from different types of nuts showed element concentration in the range 2.9-16.9 ng g(-)(1). Lower levels of arsenic were found in defatted material (<0.1 ng g(-)(1) with the exception of Brazil nuts purchased with and without shells, 3.0 and 2.8 ng g(-)(1) respectively). For speciation analysis of arsenic in nut oils, elemental species were extracted from 2 g of oil with 12 mL of chloroform/methanol (2:1) and 8 mL of deionized water. The aqueous layer, containing polar arsenic species, was evaporated and the residue dissolved and analyzed by ion chromatography-ICP-MS. The anion exchange chromatography enabled separation of As(III), dimethylarsinic acid (DMAs(V)), monomethylarsonic acid (MMAs(V)), and As(V) within 8 min. Several types of nuts were analyzed, including walnuts, Brazil nuts, almonds, cashews, pine nuts, peanuts, pistachio nuts, and sunflower seeds. The recovery for the speciation procedure was in the range 72.7-90.6%. The primary species found in the oil extracts were As(III) and As(V). The arsenic concentration levels in these two species were 0.7-12.7 and 0.5-4.3 ng g(-)(1), respectively. The contribution of As in DMAs(V) ranged from 0.1 +/- 0.1 ng g(-)(1) in walnuts to 1.3 +/- 0.3 ng g(-)(1) in pine nuts. MMAs(V) was not detected in almonds, peanuts, pine nuts, sunflower seeds, or walnuts, and the highest concentration was found in pistachio nuts (0.5 +/- 0.2 ng g(-)(1)).     

Enzyme-catalyzed change of antioxidants content and antioxidant activity of asparagus juice

A pectolytic enzyme preparation from Aspergillus niger (pectinase AN) decreased most rutin content and antioxidant activity of asparagus juice. To investigate the mechanism of such loss, we analyzed several possible related enzyme activities in pectinase AN. We found that the activity of pectinase AN to oxidize guaiacol had no significant difference with or without the presence of H2O2; thus it was laccase activity, not peroxidase (PO) activity, that pectinase AN contained. We did not find any polyphenol oxidase (PPO) activity in pectinase AN. Laccase in pectinase AN could be the major cause of loss of rutin and antioxidant activity of asparagus juice. When most laccase activity of pectinase AN was inactivated after heating at 70 degrees C for 1.5 min and incubated with asparagus juice, the loss rate of rutin was only 9% of that treated with unheated pectinase AN, and the antioxidant activity was even increased. Rhamnosidase activity was detected in pectinase AN and can change rutin in asparagus juice to quercetin-3-glucoside, which has higher antioxidant activity than rutin. This may explain the increase of antioxidant activity of asparagus juice treated with heated pectinase AN that still contained some rhamnosidase activity. The discovery of our research is helpful to produce juice with high antioxidant activity and high health benefits in the juice industry.     

Molecular mimicry regulates ABA signaling by SnRK2 kinases and PP2C phosphatases

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.     

Is the Macy's in my mall going to close? Uncovering the factors associated with the closures of Macy's,Sears, and J.C. Penney stores

This study analyzes three national department store chains in order to identify the factors most associated with their store closures. A binary logistic regression revealed some consistencies and differences in the associations. Larger stores are less likely to close for all three chains. Macy's and Sears stores are less likely to close in large malls (than freestanding stores) and if they are located in the West. J.C. Penney stores in the west are also less likely to close than in other regions, but stores in large shopping centers are more likely to close than freestanding stores. Store age was only significant for J.C. Penney stores, and indicated that older stores are more likely to close. Implications for retail managers and city economic vitality are mentioned and future research possibilities are discussed.     

Changes in phosphorus fractions in three tropical soils amended with corn cob and rice husk biochars

ABSTRACT

The formation of phosphorus (P) compounds including iron-P, aluminum-P and calcium-P in highly weathered tropical soils can be altered upon biochar addition. We investigated the effect of corn cob biochar (CC) and rice husk biochar (RH) pyrolyzed at three temperatures (300°C, 450°C and 650°C) on phosphorus (P) fractions of three contrasting soils. A 90d incubation study was conducted by mixing biochar with soil at a rate of 1% w/w and at 70% field capacity. Sequential P fraction was performed on biochar, soil and soil-biochar mixtures. Increase in most labile P (resin-P_i, NaHCO₃-P_i) and organic P fraction (NaHCO₃-P_o + NaOH-P_o) in CC and RH biochars were inversely related to increasing temperature. HCl-P_i and residual P increased with increasing temperature. Interaction of CC and RH with soils resulted in an increase in most labile P as well as moderately labile P (NaOH-P_i) fractions in the soils. CC increased most labile P in the soils more than RH. The increase in most labile P fraction in soils was more significant at relatively lower temperatures (300°C and 450°C) than 650°C. However, the increase in HCl-P_i and residual P of the soils was more predominant at high temperature (650°C). The study suggested that biochar pyrolyzed at 300–450°C could be used to increase P bioavailability in tropical soils.     

Changes in the Quality of Refined Fish Oil in an Accelerated Storage Study

ABSTRACT

The aim of this study was to prepare the refined oil derived from Sardinella longiceps by a step-wise procedure of degumming, bleaching, and deodorization. The refined sardine oil showed greater susceptibility toward oxidation than the crude oil, but the addition of ethyl acetate fractions of the red seaweeds Hypnea musciformis, Kappaphycus alvarezii, and Jania rubens with great antioxidant potential significantly increased the oxidative stability of the refined oil. The refined oil supplemented with the ethyl acetate fraction of these seaweeds indicated more noteworthy oxidative stability indices (≥ 0. 51 h) than α-tocopherol. The induction time was greater for refined oil added with H. musciformis (1.26 h) than butylated hydroxytoluene (1.04 h) and α-tocopherol (0.4 h). No traces of aromatic (δ 6.7–7.5 ppm), hydroperoxides, and aldehydes (δ 9–10 ppm) in the ¹H-NMR spectra of the refined oil supplemented with seaweed extracts at the baseline and after the accelerated storage study demonstrated that the seaweed extracts were able to prevent the formation of secondary oxidation products in the unsaturated system during storage. This study demonstrated the potential of seaweeds as natural alternatives to the synthetic antioxidants to prevent the rancidity of the refined fish for use in food and pharmaceutical industries.     

Multiple watershed alterations influence fish community structure in Great Plains prairie streams

Stream fish distributions are commonly linked to environmental disturbances affecting terrestrial landscapes. In Great Plains prairie streams, the independent and interactive effects of watershed impoundments and land cover changes remain poorly understood despite their prevalence and assumed contribution to declining stream fish diversity. We used structural equation models and fish community samples from third‐order streams in the Kansas River and Arkansas River basins of Kansas, USA to test the simultaneous effects of geographic location, terrestrial landscape alteration, watershed impoundments and local habitat on species richness for stream‐associated and impoundment‐associated habitat guilds. Watershed impoundment density increased from west to east in both basins, while per cent altered terrestrial landscape (urbanisation + row‐crop agriculture) averaged ~50% in the west, declined throughout the Flint Hills ecoregion and increased (Kansas River basin ~80%) or decreased (Arkansas River basin ~30%) to the east. Geographic location had the strongest effect on richness for both guilds across basins, supporting known zoogeography patterns. In addition to location, impoundment species richness was positively correlated with local habitat in both basins; whereas stream‐species richness was negatively correlated with landscape alterations (Kansas River basin) or landscape alterations and watershed impoundments (Arkansas River basin). These findings suggest that convergences in the relative proportions of impoundment and stream species (i.e., community structure) in the eastern extent of both basins are related to positive effects of increased habitat opportunities for impoundment species and negative effects caused by landscape alterations (Kansas River basin) or landscape alterations plus watershed impoundments (Arkansas River basin) for stream species.     

Movement patterns of Brook Trout in a restored coastal stream system in southern Massachusetts

Coastal Brook Trout (Salvelinus fontinalis) populations are found from northern Canada to New England. The extent of anadromy generally decreases with latitude, but the ecology and movements of more southern populations are poorly understood. We conducted a 33‐month acoustic telemetry study of Brook Trout in Red Brook, MA, and adjacent Buttermilk Bay (marine system) using 16 fixed acoustic receivers and surgically implanting acoustic transmitters in 84 individuals. Tagged Brook Trout used the stream, estuary (50% of individuals) and bay (10% of individuals). Movements into full sea water were brief when occurring. GAMM models revealed that transitions between habitat areas occurred most often in spring and fall. Environmental data suggest that use of the saline environment is limited by summer temperatures in the bay. Movements may also be related to moon phase. Compared to more northern coastal populations of Brook Trout, the Red Brook population appears to be less anadromous overall, yet the estuarine segment of the system may have considerable ecological importance as a food resource.