Investigations on the specificity of thiophilic interaction for monoclonal antibodies of different subclasses

A comparative study was carried out to investigate the influence of different mouse antibody subclasses on the chromatographic behaviour on thiophilic supports. Cell-free supernatants from different mouse-mouse hybridoma cultures in a standard medium were purified on thiophilic agarose and Fractogel EMD TA. The adsorption capacities and purification factors were monitored under optimised adsorption conditions. The different isotypes did not differ significantly regarding capacity of the thiophilic matrix, but the purity of the eluted antibody fractions was significantly lower for the IgG_2a subclass compared to all other murine antibodies. A significant copurification of proteins from cell culture supernatant with antibodies of the IgG_2a subclass indicated a restriction in the universal nature of thiophilic interaction.     

Binding and purification of plasmid DNA using multi-layered carbon nanotubes

We propose a new method for the separation of nucleic acids using multi-layered carbon nanotubes (CNTs) as an adsorbent. According to agarose gel electrophoresis, oxidized water-stable CNTs adsorb certain forms of nucleic acids, such as high molecular weight RNA, chromosomal DNA, linear and denatured forms of plasmid DNA. However, CNTs do not adsorb supercoiled form of plasmid DNA. Nucleic acids bound to CNTs can be readily removed by centrifugation whereas supercoiled plasmid DNA remains in solution. Upon the addition of divalent metal ions supercoiled plasmid DNA forms relatively stable complexes with CNTs due to chelation. Thus, new details about association of nucleic acids with CNTs were revealed and stoichiometry of the complexes was estimated. Our results can be used for fine purification of supercoiled plasmid DNA for gene therapy applications as well as manipulation of nucleic acids for biosensor design.     

In vitro studies on the evaluation of mycotoxin detoxifying agents for their efficacy on deoxynivalenol and zearalenone

A simple in vitro system was developed to study the efficacy of commercially available mycotoxin detoxifying agents and adsorbing substances as feed additives to detoxify deoxynivalenol (DON) and zearalenone (ZON) in situ. The in vitro model simulates the conditions (pH, temperature and transit time) of the porcine gastrointestinal tract, as pigs react most sensitively to these mycotoxins. The commercially available products were not effective in detoxifying DON and ZON under the applied conditions, while activated carbon was able to bind both toxins and cholestyramine, and a modified aluminosilicate showed good adsorption abilities for ZON. Data obtained in dose dependency studies showed an estimated adsorption capacity of cholestyramine and the modified aluminosilicate of 11.7 and 5.7?g ZON/kg detoxifying agent. The in vitro system deployed in the present study was demonstrated to be a simple, helpful tool in screening substances for their ability to detoxify DON and ZON under the simulated conditions of the porcine gastrointestinal tract. Nonetheless in vivo experiments are indispensable to proof the efficacy.     

Activation Methods of Carbonaceous Materials Obtained from Agricultural Waste

Activated carbons belong to the most widely used adsorbent materials. The utility of these materials mainly depends on their chemical surface and porous structure. The method of activation and the nature of the used precursor greatly influence the pore structure and surface functional groups of the activated carbon. Therefore, the main objective of current investigations is to develop or modify the activation method in an optimal manner using appropriate precursors. This review compiles the results of various studies on the synthesis of activated carbons from agricultural waste. Various activation methods, such as physical, chemical, physicochemical, and microwave activation, are discussed. The effects of carbonization and activation parameters, such as temperature, activating agent, and residence time, toward the properties of the activated carbon are reviewed.