Magnetic-activated carbon composites derived from iron sludge and biological sludge for sulfonamide antibiotic removal.

Novel magnetic-activated carbon composites (MACs) were synthesized via coupling of a glucose-assisted hydrothermal pretreatment and subsequent thermal treatment using iron sludge and biological sludge. The adsorption properties of MACs for sulfonamide antibiotic removal from aqueous solution were investigated. Results revealed that the MACs had a high specific surface area with well-distributed magnetic nano-sized Fe3O4/Fe0 particles with a graphitic shell. This finding indicates that the ferric compounds in the iron sludge were not only converted into magnetic ferrite but also worked as activators for graphitization of the surrounding amorphous carbon. The pseudo-second-order kinetics and Langmuir models were shown to well fit sulfonamide antibiotic adsorption on the MACs. There was a high correlation between the kl·qm and physicochemical parameters of the sulfonamides. The three parameters are molecular polarizability, octanol-water partition coefficient, and solubility, respectively. The sulfonamide adsorption by the MACs was highly pH dependent. Hydrophobic interaction, π-π interaction, as well as electrostatic interaction, played dominant roles in the sulfonamide adsorption.

Identification of common antigens of three pathogenic Nocardia species and development of DNA vaccine against fish nocardiosis.

Fish nocardiosis is a chronic granulomatous bacterial disease and three pathogens have been reported so far, including Nocardia asteroids, N. seriolae and N. salmonicida. However, the absence of antigen markers is a bottleneck for developing effective vaccines against fish nocardiosis. In this study, the antigenicity of whole-cell protein of these three pathogenic Nocardia species were profiled by immunoproteomic analysis and 7 common immunogenic proteins were identified as follows: molecular chaperone DnaK (DnaK), molecular chaperone GroEL (GroEL), 30 S ribosomal protein S1 (RpsA), TerD family protein (TerD), FHA domain-containing protein (FHA), 50 S ribosomal protein L7/L12 (RplL) and PspA/IM30 family protein (PspA). Furthermore, the DNA vaccine encoding FHA gene against fish nocardiosis was developed and its efficacy was investigated in hybrid snakehead. The results suggested that it needed at least 7 d to transport pcDNA-FHA DNA vaccine from injected muscle to head kidney, spleen and liver and stimulate host's immune system for later protection. In addition, non-specific immunity paraments (serum lysozyme (LYZ), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) activities), specific antibody (IgM) titers production and immune-related genes (MHCIα, MHCIIα, CD4, CD8α, IL-1ß and TNFα) were used to evaluate the immune response induced in pcDNA-FHA vaccinated hybrid snakehead, it proved that all these mentioned immune activities were significantly enhanced after immunization. The results also showed hybrid snakehead vaccinated with pcDNA-FHA had higher survival rate (79.33%) compared with the controls after challenge with N. seriolae, indicating that the pcDNA-FHA DNA vaccine can supply immune protection against N. seriolae infection. Taken together, this study may warrant further development of these common immunogenic proteins as the antigens for vaccine or diagnosis and facilitate the prevention and treatment of fish nocardiosis.