No abstract

The behavior of human immunoglobulin G (IgG) and antigen-binding fragment (Fab fragment) adsorption onto phospho-L-tyrosine immobilized on agarose (P-Tyr-agarose) was evaluated by pseudoaffinity chromatography. The effects of buffer systems MES, MOPS, Bis-Tris, Tris-HCl and sodium phosphate (NaP) and pH on IgG adsorption were studied and high purity values were obtained (96%, based on ELISA analysis of albumin, transferrin and immunoglobulins A, G and M) when IgG was purified from human plasma diluted in 10 mmol L −1 NaP buffer at pH 6.0. The capture of IgG by the P-Tyragarose was also promising, since 91% of the IgG was adsorbed when plasma was diluted in 25 mmol L −1 MES buffer at pH 5.5, recommending its use for IgG depletion from human plasma under this condition. The experimental data on IgG adsorption kinetics were in agreement with the pseudo-second-order model. The adsorption isotherm data were well described by the Langmuir-Freundlich model with the value of parameter n being <1 (0.72), indicating negative cooperativity. Selectivity was achieved on P-Tyr-agarose from digested human IgG in HEPES 25 mmol L −1 buffer at pH 7.0where Fab fragments were obtained in eluted fractions without Fc fragments (but with uncleaved IgG) with 86.2% recovery.

Polymeric composites of poly (butylene adipate-co-terephtalate) were reinforced with commercial organophylic montmorilonite clay Cloisite and tensile tests provided mechanical properties. The study of the Elastic modulus of pure PBAT (poly (butylene adipate-co-terephtalate)) and different composites demonstrates that Cloisite presents potential for reinforcement of PBAT.

Brazilian ginseng (Pfaffia glomerata) is a native plant from Brazil traditionally used in folk medicine to treat several diseases, as nutritional supplement for athletes. Its properties are associated to the steroid beta-ecdysone present in the Brazilian ginseng roots. Recently, inulin-type polysaccharides, also named fructooligosaccharides (FOS) were found in Brazilian ginseng, which are considered prebiotic compounds. The aim of this study was to evaluate the preservation of functional compounds in the powdered Brazilian ginseng extract and to characterize its physical properties.The results showed that the beta-ecdysone and FOS contents of Brazilian ginseng powders were preserved after the drying processes and the physical properties of powders enables its use as instant tea or functional ingredient.

The antibodies and fragments represent an important class of molecules employed in clinical diagnosis in vitro and in vivo, and in the area of biosensors. The need for research development in this area is great, aiming an efficient purification, using low cost techniques. This work studies the separation of Fab fragments of human immunoglobulin G (IgG) through pseudoafinity chromatography using ortho-phosphotyrosine (OPT) as the ligand.