Optimal isotherm model and explanatory characteristics associated with metal ion adsorption on humic acids isolated from forest soils

Journal of Soils and Sediments - Understanding the mechanisms of interaction between humic acids (HAs) and metal ions in soil media is essential for integrated environmental and agricultural...     

DISTRIBUTION AND PHYTOAVAILABILITY PREDICTION OF ZINC IN AGRICULTURAL CALCAREOUS SOILS

The extractability and distributions of zinc (Zn) were evaluated in calcareous agricultural soils from South-West Iran. Both single [diethylenetriaminepentaacetic acid (DTPA)] and sequential extraction procedures (Singh scheme) were applied to 20 representative soils. The DTPA extractable zinc levels were low (on average 3.34%). The sequential extraction procedures were also utilized for the study of zinc phytoavailability in maize plants (Zea mays L.) in a greenhouse experiment. The Singh scheme was significantly better than DTPA plus soil properties in phytoavailability prediction of zinc in soils. Significant correlations were found between the amounts of DTPA extractable zinc and the iron (Fe) oxides-bound (AFe and CFe) and residual fractions extracted by the Singh procedure. Zinc concentrations in plant samples (mean value of 27.49 mg kg^?1) were poorly correlated with the different extracted soil fractions (single and sequential). The Singh procedure provided better predictions of zinc uptake by plants than DTPA extraction method.     

Recombinant Production of a Novel Fusion Protein: Listeriolysin O Fragment Fused to S1 Subunit of Pertussis Toxin

Background:Some resources have suggested that genetically inactivated PTs bear a more protective effect than chemically inactivated products. This study aimed to produce new version of PT, by cloning an inactive PTS1 in a fusion form with N-terminal half of the LLO pore-forming toxin. Methods:Deposited pdb structure file of the PT was used to model an extra disulfide bond. Codon-optimized ORF of the PTS1 was used to make recombinant constructs of PTS1 and LLO-PTS1 in the pPSG-IBA35 vector. The recombinant PTS1 and LLO-PTS1 proteins were expressed in BL21 DE3 and SHuffle T7 strains of E. coli and purified by affinity chromatography. Cytotoxic effects of the recombinant proteins were examined in the MCF-7 cell line. Results:The purity of the products proved to be more than 85%, and the efficiency of the disulfide bond formation in SHuffle T7 strain was higher than BL21 DE3 strain. No cytotoxicity of the recombinant proteins was observed in MCF-7 cells. Soluble recombinant PTS1 and LLO-PTS1 proteins were produced in SHuffle T7 strain of E. coli with high efficiency of disulfide bonds formation. Conclusion:The LLO-PTS1 with corrected disulfide bonds was successfully expressed in E. coli SHuffle T7 strain. Due to the safety for human cells, this chimeric molecule can be an option to prevent pertussis disease if its immunostimulatory effects would be confirmed in the future. Key Words: Adjuvant, Cloning, Fusion protein, Pertussis toxin     

Rotavirus antibody assays on monkey sera: a comparison of enzyme immunoassay with neutralization and complement-fixation tests.

An enzyme immunoassay (EIA) for the detection of rotaviral antibodies was developed, using a purified, cell culture-grown SA 11 viral antigen and alkaline phosphatase as an enzyme label. This technique was evaluated by comparative testing with tube neutralization and complement-fixation assays on a collection of simian sera. There was close correlation between positive and negative results obtained by EIA and by neutralization. The EIA was as easy to perform as complement fixation testing, but showed greater sensitivity and fewer nonspecific reactions. Thus, EIA was shown to be a very suitable test for routine detection of rotaviral antibodies in serum. Results of neutralization tests suggested that the monkeys (mostly rhesus macaques) in the present study were infected with viruses varying in their antigenic relatedness to SA 11 virus and to a British isolate of calf rotavirus.