Synthesis of Zearalenone Immunogen and Comparative Analysis of Antibody Characteristics

Background. This study aimed to explore the zearalenone (ZEN) immunogen synthesis method, immunogenicity, and antibody characteristics and to lay a foundation for the establishment of immunoassay methods for ZEN single residue and ZEN and its analogs total residue. Methods. Based on the molecular structure and active sites of ZEN, oxime active ester (OAE), condensation mixed anhydride (CMA), formaldehyde (FA), and 1,4-butanediol diglycidyl ether method (BDE) were designed and used for immunogen (ZEN-BSA) synthesis. The immunogens were identified by infrared (IR) and ultraviolet (UV) spectra and gel electrophoresis (SDS-PAGE) and were then used to immunize Balb/c mice to prepare ZEN polyclonal antibody (ZEN pAb). The titers and sensitivity of the ZEN pAb were determined by indirect noncompetitive ELISA (inELISA) and indirect competitive ELISA (icELISA), respectively, and its specificity was assessed by the cross-reaction test (CR). Results. ZEN-BSA was successfully synthesized, and the molecular binding ratios of ZEN to BSA were 17.2 : 1 (OAE), 14.6 : 1 (CMA), 9.7 : 1 (FA), and 8.3 : 1 (BDE), respectively. The highest inELISA titers of ZEN pAb of each group were 1 : (6.4 × 103) (OAE), 1 : (3.2 × 103) (CMA), 1 : (1.6 × 103) (FA), and 1 : (1.6 × 103) (BDE), respectively. The 50% inhibition concentrations (IC50) for ZEN by icELISA of each group were 11.67 μg/L (OAE), 16.29 μg/L (CMA), 20.92 μg/L (FA) and 24.36 μg/L (BDE), respectively. ZEN pAb from the mice immunized with ZEN-BSA (OAE) and ZEN-BSA (CMA) had class broad specificity to ZEN and its analogs. The CRs of ZEN pAb with α-ZAL, β-ZAL, α-ZOL, β-ZOL, and ZON were 36.53%, 16.98%, 64.33%, 20.16%, and 10.66%, respectively. ZEN pAb from the mice immunized with ZEN-BSA (FA) and ZEN-BSA (BDE) had high specificity for ZEN. The CRs of ZEN pAb with its analogs were all less than 1.0%. Conclusion. This study demonstrated that the preparation of the class broad-specificity antibodies of ZEN and its analogs can be achieved by immunizing animals with the immunogen ZEN-BSA prepared by the OAE method, while the preparation of highly specific antibodies can be achieved by immunizing animals with the immunogen ZEN-BSA prepared by the FA method. These findings lay the material and technical foundation for immunoassay of ZEN single residue and ZEN and its analogs total residue.

DƯ LƯỢNG HÓA CHẤT BẢO VỆ THỰC VẬT CƠ CLO TRONG MỘT SÓ SINH VẬT VÙNG TRIỀU PHÍA BẮC VIỆT NAM

Organochlorinated pesticides (OCPs) had been used widely in agriculture for protecting crop, eliminating insects. However, OCPs are banned in most countries because of their toxicity, long persistence and bio-accumulation. They are listed in carcinogen group and POP group (Persistent organic pollutants). In Vietnam, OCPs were banned in 1990s, but their residues are still found in the environments, including seawater, sediment and organisms. This paper presents the survey data of residues of OCPs in some organisms living in tidal flats in the northern part of Vietnam during the year 2013–2014. The results show that the total residue of OCPs in shellfish ranged from 5.57 µg/kg to 116.04 µg/kg dry weight. Compared with the American Guide for mollusk shellfish (2007), it is found that the organisms living in the tidal flats were not polluted by OCPs. However, these compounds can be accumulated in fat tissue even in very low concentration. Therefore, their presence in organism is alarming.

The influence of sodium-polyacrilic macromolecular chain length to the powder detergents secondary washing performances

In order to investigate the influence of sodium-polyacrylate polymer as a co-builder in addition to the carbonate/zeolite builders in detergent builder system, secondary washing performances of powder laundry detergent containing equal percentage of sodium polyacrylate with the different weight average molar mass, Mw, have been examined. The value of the degree of whiteness, elongation at break, and total residue content are the most important secondary washing performances that significantly depend on sodium polyacrylates efficiency used as crystal inhibitors, stabilizers for suspended soil, and agents for soil redisposition prevention on fabric surface. The values of the whiteness and elongation at break for cotton fabrics increase with the increase of average weight molecular mass, Mw, up to the value of 70000 g/mol, while in the case of further increase of weight average molar mass up to the 250000 g/mol value of these characteristics begin to decline. The values of the total residue content after combustion indicate an increase in its content with the increase of weight average molar mass of 3000 to 70000 g/mol, while the highest value has been reached in the sample of detergent containing sodiumpolyacrilic with the weight average molar mass of 250000 g/mol. All detergent samples show no significant dependence of the secondary washing characteristics on the number of washing cycles.

Effects of crop rotation and fallow residue management on maize growth, yield and soil carbon in a savannah-forest transition zone of Ghana

SUMMARYThe purpose of the present study was to investigate the effects of seven maize (Zea mays)–fallow rotation and fallow residue management treatments on growth, maize yield and soil carbon within a savannah-forest farming zone of Ghana. Over a 4-year period, maize rotated with bare fallow (control) produced an average maize biomass and yield of 4·0 and 1·0 t/ha/yr, respectively. Maize rotated with elephant grass (Pennisetum purpureum) with the fallow grass residue burning produced an average maize biomass and yield of 8·0 and 2·0 t/ha/yr, respectively. The removal of the fallow grass biomass (9·0 t/ha/yr) by burning resulted in a low total residue (maize stover+fallow residue) returned to the soil (7·0 t/ha/yr). The total residue returned to the soil was 14·0 t/ha/yr. Despite the larger total residue returned to the soil by the incorporation treatment, the performance of the maize was not significantly different from that of the fallow residue burning treatment. Maize rotated with cowpea (Vigna unguiculata), mucuna (Mucuna pruriens) or pigeon pea (Cajanus cajan) produced similar maize biomass of 8·0 t/ha/yr and yields of 2·0 t/ha/yr, but with higher variability for the maize–cowpea rotation. Biomass produced by fallow cowpea, mucuna or pigeon pea were 4·0, 5·0 and 8·0 t/ha/yr, respectively, and total residues added to the soil were 13·0, 13·0 and 15·0 t/ha/yr, respectively. Maize–grass rotation with fertilizer application to the maize resulted in biomass and yield production of 11·0 and 3·0 t/ha/yr, respectively, and fallow grass production of 12·0 t/ha/yr. The total residue returned to the soil was 18·0 t/ha/yr. Soil organic carbon (SOC) declined under all treatments over time, with the control losing about 55% of the initial SOC by the end of the trial. The decline in SOC was 19% for the fertilized maize–grass rotation, but all other treatments lost between 33 and 44% SOC. Overall, the fertilized maize–grass and maize–pigeon pea rotations were identified as those that sustained relatively high maize yields, returned large residue amounts to the soil and minimized soil carbon loss.

Transformation and degradation of fenamiphos nematicide and its metabolites in soils

Fenamiphos is an important nematicide{insecticide and commonly used in horticultural crops and turfs in Australia. We studied the transformation/degradation of fenamiphos under controlled conditions, in surface and subsurface soils from the Swan Coastal Plain of Western Australia. In the sandy surface soil, fenamiphos (Fen) was rapidly oxidised to its sulfoxide (FenSO) analogue. Further oxidation of FenSO to sulfone (FenSO2), however, was found to be very slow, resulting in an accumulation of FenSO. Little accumulation of FenSO2 occurred during the study period (139 days). The time taken for 50% loss of the total residue of fenamiphos (Fen+FenSO+FenSO2) was found to be approximately 50 days in the surface soil and about 140 days in the subsurface soil. Simulations using the LEACHM model showed that the rate of transformation of Fen to FenSO in the surface soil (k1 = 0·5/day) was 100 times faster than that of FenSO to FenSO2 (k2 = 0·005/day). In the subsurface soil, the difference between the 2 oxidation steps was much smaller (4-fold). The conversion of Fen to FenSO was much faster in the surface soil (k1 = 0·5/day) than the subsurface soil (k1 = 0·02/day). The observed differences in transformation behaviour of Fen between the surface and subsurface layers of soil appear to be associated with the differences in the microbial biomass and the organic matter contents of the soils. The slower transformation of Fen in the subsurface soils can have major implications on its potential for groundwater contamination in vulnerable areas, such as the Swan Coastal Plain of Western Australia.