The persulfate oxidation of fulvic acids

Persulfate oxidation of two fulvic acids from different soils was accomplished. This is a new mild chemical degradative method which differentiates between fulvic acids isolated from soils developed under widely differing environments. A fulvic acid isolated from an Humic Haplorthod gives as major oxidation products phenolic acids, whereas a fulvic acid from an Andic Hapludult yields benzenecarboxylic acids as most abundant compounds. The possibility to differentiate between fulvic acids from different soils, as chemical degradation with persulfate does, offers interesting prospects to the characterization of humic materials.     

Pyrolysis of a soil humic acid and of their hydrolyzed and methylated products

Pyrolysis of soil humic acid yields a variety of products arising from heterogeneous materials associated to the humic structure and from this self. After acid hydrolysis most of the compounds related to proteins, polysaccharides and lignin dissappear. Adsorbed compounds such as fatty and dicarboxylic acids are released after methylation and subsequent pyrolysis. In addition pyrolysis produces aromatic and substituted aromatic hydrocarbons. All the identified pyrolysis products have also been isolated by different complex and time-consuming chemical degradations and solvent extraction procedures. Pyrolysis provide some evidence of the humic acid structure.     

El Niño induced local extinction of coral reef bryozoan species from Northern Bahia, Brazil

The 1997-1998 El-Niño Southern Oscillation was the most severe on record and dramatically impacted corals worldwide. However, the effect of this event on the associated community of reef organisms has received much less attention. The composition of the bryozoan assemblage from the coral reefs of Northern Bahia, Brazil were monitored annually from 1995 to 2000, allowing the investigation of the effects of this large-scale stressor on an important, diverse, yet understudied component of the coral reef system. Bryozoan samples (35 replicates/reef) were collected during April/May from four shallow bank reefs (10-40 m depth) located a few kilometres off the coast, together with measurements of the associated environmental parameters. Currently 157 species have been recorded from the study area, but significant reductions in density and diversity were apparent between pre- and post El-Niño Southern Oscillation (ENSO) years, multivariate analysis denoting significant changes in assemblage composition. A total of 61 species were unrecorded following the 1997-1998 ENSO event (22 species from 1997; 25 further species from 1998 and 14 more from 1999). These included several species endemic to Brazil, suggesting that the 1997-1998 ENSO has had a marked influence on the reef bryozoan community, resulting in the local extinction of several species. Bryozoan mortalities were probably initiated by elevated temperatures, but continued disappearance of species for 2 years after ENSO suggests other indirect factors are also influential. These results demonstrate that ENSO events can have severe long-term impacts on the biodiversity of coral reefs, with important conservation consequences.     

Irrigation of Landfill Leachates in Energy Forests — A Technique to Recover Nutrients from Municipal Solid Wastes

From an ecological point of view it is important to close nutrient cycles by recirculating mineral nutrients from the urban society back to agriculture and forestry, and thereby obtaining a sustainable resource utilisation. A part of this cycle is illustrated by irrigation of bioreactor landfill leachates on short rotation forests. This paper presents a budget for nutrients and heavy metals, beginning with the leachates and ending with the harvested tree fraction. The hypotheses were: The applied minerals deliver nutrients to the trees. The nutrient content in the accumulating biomass corresponds to the amount of mineral nutrients applied. The concentrations of heavy metals in the trees will remain low. The uptake of elements in birch was for P 35%, Ca 1. 2%, Cd 64%, Cu 10%, Mn 19%, Ni 0. 11%, and for Zn 26% of the supplied amounts. It was concluded that nutrients, with some exceptions, are supplied in sufficient amounts from the irrigated leachates to achieve optimal biomass growth, that the amounts of ions immobilised by the plants were significantly lower compared to the applied amounts, and that the concentrations of heavy metals are not increasing in the trees after irrigation. The overall conclusion is that a leachate irrigation system is efficient if the available vegetated land area is large enough for effective nutrient uptake, but the nutrient ratio may need to be balanced to meet the needs of the plants.     

Fate of Cry1Ab protein in agricultural systems under slurry management of cows fed genetically modified maize (Zea mays L.) MON810: a quantitative assessment

The objective of the study was to track the fate of recombinant Cry1Ab protein in a liquid manure field trial when feeding GM maize MON810 to dairy cows. A validated ELISA was applied for quantification of Cry1Ab in the agricultural chain from GM maize plants, feed, liquid manure and soil to crops grown on manured fields. Starting with 23.7 μg of Cry1Ab g(-1) dry weight GM maize material, a rapid decline of Cry1Ab levels was observed as 2.6% and 0.9% of Cry1Ab from the GM plant were detected in feed and liquid manure, respectively. Half of this residual Cry1Ab persisted during slurry storage for 25 weeks. After application to experimental fields, final degradation of Cry1Ab to below detectable levels in soil was reported. Cry1Ab exhibited a higher rate of degradation compared to total protein in the agricultural processes. Immunoblotting revealed a degradation of the 65 kDa Cry1Ab into immunoreactive fragments of lower size in all analyzed materials.     

Assessment of genetic diversity among African cassava Manihot esculenta Grantz accessions resistant to the cassava mosaic virus disease using SSR markers

A study was conducted to determine the extent of genetic diversity among African cassava (Manihot esculenta Crantz) accessions resistant to the cassava mosaic virus disease (CMD), using simple sequence repeat (SSR) markers. The accessions included a breeding stock (clone 58308), five improved lines, 62 CMD resistant and 10 CMD susceptible landraces. Genetic diversity was assessed among accessions in five cluster groups derived from UPGMA analysis on data from 18 SSR primer pairs. Average gene diversity, He, was high in all cluster groups, with an average heterozygosity of 0.591 ± 0.061. The estimator of inbreeding Fis revealed a low level of inbreeding within groups and averaged −0.262 ± 0.142. Gene diversity among all accessions was 51.4% and gene diversity within cluster groups was 46.6%, while 4.8% was due to diversity between the different cluster groups. The amount of genetic differentiation measured by Gst and Fst were 9.6% and 12.1% respectively, indicating a weak genetic structure.     

Application of two-dimensional gel electrophoresis to interrogate alterations in the proteome of genetically modified crops. 1. Assessing analytical validation

Current tools used to assess the safety of food and feed derived from modern biotechnology emphasize the investigation of possible unintended effects caused directly by the expression of transgenes or indirectly by pleiotropy. These tools include extensive multisite and multiyear agronomic evaluations, compositional analyses, animal nutrition, and classical toxicology evaluations. Because analytical technologies are rapidly developing, proteome analysis based on two-dimensional gel electrophoresis (2DE) was investigated as a complementary tool to the existing technologies. A 2DE method was established for the qualitative and quantitative analysis of the seed proteome of Arabidopsis thaliana with the following validation parameters examined: (1) source and scope of variation; (2) repeatability; (3) sensitivity; and (4) linearity of the method. The 2DE method resolves proteins with isoelectric points between 4 and 9 and molecular masses (MM) of 6-120 kDa and is sensitive enough to detect protein levels in the low nanogram range. The separation of the proteins was demonstrated to be very reliable with relative position variations of 1.7 and 1.1% for the pI and MM directions, respectively. The mean coefficient of variation of 254 matched spot qualities was found to be 24.8% for the gel-to-gel and 26% for the overall variability. A linear relationship (R2 > 0.9) between protein amount and spot volume was demonstrated over a 100-fold range for the majority of selected proteins. Therefore, this method could be used to interrogate proteome alterations such as a novel protein, fusion protein, or any other change that affects molecular mass, isoelectric point, and/or quantity of a protein.