ABSTRACT
The application of pyrogenic materials in immobilization processes of metalloids represents a burning issue in environmental and waste applications and management. The main objective of this study was to characterize the effect of biomass pretreatment by Cu, Fe and Mg blending and pyrolysis temperature on As sorption efficiency as a model of anionic metalloids from model solutions and As immobilization in old mine soil by pyrogenic materials. The physico-chemical characterization of engineered materials produced in slow pyrolysis process at 400 and 700°C from metal-blended hard wood chips (30% w/w) showed increasing of surface areas (1.4-1.8-fold), changes in pH, and more than 50% decrease in total C content. The batch sorption processes of As ions by Cu-modified pyrogenic materials (CuPM), Fe-modified pyrogenic materials (FePM), and Mg-modified pyrogenic materials (MgPM) showed increasing uptake in order CuPM700 (Qmax 2.56 mg g-1) < CuPM400 (Qmax 3.88 mg g-1) < FePM700 (Qmax 5.90 mg g-1) < MgPM700 (Qmax 7.42 mg g-1) < MgPM400 (Qmax 9.59 mg g-1) < FePM400 (Qmax 10.55 mg g-1). Engineered pyrogenic materials produced at 400°C showed higher immobilization effect on soluble As in soil pore water of old mine site soil from Mediterranean area. FePM400 reduced mobility of arsenic > 3.2 times and MgPM400 > 5 times compared to control. Promising pyrogenic material MgPM400 showed immobilization effect also on additional heavy metals (Cd, Cu, Fe, Mn, Pb, Sr, Zn) present in studied soil.
Subject(s)
Arsenic/chemistry , Environmental Restoration and Remediation/methods , Mining , Pyrogens/chemistry , Soil Pollutants/chemistry , Adsorption , Biomass , Mediterranean Region , Metals, Heavy/chemistry , Pyrogens/chemical synthesis , PyrolysisABSTRACT
Streptococcal pyrogenic exotoxin C (SPE C) is a superantigen produced by many strains of Streptococcus pyogenes that (along with streptococcal pyrogenic exotoxin A) is highly associated with streptococcal toxic shock syndrome (STSS) and other invasive streptococcal diseases. Based on the three-dimensional structure of SPE C, solvent-exposed residues predicted to be important for binding to the TCR or the MHC class II molecule, or important for dimerization, were generated. Based on decreased mitogenic activity of various single-site mutants, the double-site mutant Y15A/N38D and the triple-site mutant Y15A/H35A/N38D were constructed and analyzed for superantigenicity, toxicity (lethality), immunogenicity, and the ability to protect against wild-type SPE C-induced STSS. The Y15A/N38D and Y15A/H35A/N38D mutants were nonmitogenic for rabbit splenocytes and human PBMCs and nonlethal in two rabbit models of STSS, yet both mutants were highly immunogenic. Animals vaccinated with the Y15A/N38D or Y15A/H35A/N38D toxoids were protected from challenge with wild-type SPE C. Collectively, these data indicate that the Y15A/N38D and Y15A/H35A/N38D mutants may be useful as toxoid vaccine candidates.
Subject(s)
Bacterial Proteins , Bacterial Vaccines/immunology , Exotoxins/immunology , Membrane Proteins , Pyrogens/immunology , Shock, Septic/immunology , Shock, Septic/prevention & control , Streptococcus pyogenes/immunology , Toxoids/immunology , Animals , Bacterial Vaccines/administration & dosage , Bacterial Vaccines/chemical synthesis , Bacterial Vaccines/genetics , Cells, Cultured , Dimerization , Disease Models, Animal , Exotoxins/administration & dosage , Exotoxins/chemical synthesis , Exotoxins/genetics , Humans , Infusion Pumps, Implantable , Lymphocyte Activation , Models, Molecular , Mutagenesis, Site-Directed , Pyrogens/administration & dosage , Pyrogens/chemical synthesis , Pyrogens/genetics , Rabbits , Streptococcus pyogenes/genetics , Structure-Activity Relationship , Toxoids/administration & dosage , Toxoids/chemical synthesis , Toxoids/genetics , Vaccines, Synthetic/chemistry , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunologyABSTRACT
Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities.
