RESUMEN
Objective To explore the relationship between brain-derived neurotrophic factor (BDNF) and 5-hydroxytryptamine (5-HT) in children with attention deficit hyperactivity disorder (ADHD) plus learning disabilities (LD) and their effects. Methods The present study included 40ADHD children with (15 cases) or without LD (25 cases) who had presented to our institute from January 2011 to October 2011,and 25 healthy children as controls as well.The serum levels of BDNF and 5-HT were compared between the 3 groups.Analysis of variance and linear correlation model were used to assess the levels and correlation of BDNF and 5-HT in the ADHD + LD group. Results The BDNF level significantly decreased in turn from the ADHD+LD group to the ADHD group to the control group (P＜0.05). The 5-HT level significantly increased in the ADHD and control groups compared with the ADHD + LD group (P＜0.05).The serum levels of BDNF and 5-HT were negatively correlated in the ADHD + LD group (r=-0.084,P=0.004). Conclusion Since the serum levels of BDNF and 5-HT are abnormal in children with ADHD plus LD,they may interact with one another and get involved in the pathological process of ADHD.
RESUMEN
Aspergillus fumigatus wild-type phytase has many favorable properties, such as a good thermorstability and a broad pH optimum. However, the specific activity of the enzyme is relative low. A. fumigatus Q23L phytase resulted in a remarkable increase in specific activity around pH4.5 - 7.0, but the pH stability of Q23L was lower than A. fumigatus wild-type phytase. To increase the pH stability of Q23L, the mutant Q23LG272E was constructed by site-directed mutagenesis with PCR. The gene of A. fumigatus wild-type phytase and the mutant genes encoding the Q23LG272E and the Q23L were correctly expressed in Pichia pastoris GS115. Enzymes were purified and their enzymatic properties were determined. The results revealed that the specific activity of the Q23L improved remarkably, which increased from 51 u/mg of the wild type to 109 u/mg at pH5.5. Meanwhile, the pH stability of Q23L, decreased evidently, especially from pH3.0 to pH4.0.The pH stability of Q23LG272E in pH3.0 - 4.5 and pH6.5 - 7.0 has been improved compared with Q23L. The specific activity of Q23LG272E basically maintained at the level of Q23L. Analysis of 3-D structure and sequence similarity were used to reveal the presumable factors influencing the enzymatic properties of Q23LG272E, and discussion for the relationship between structure and function of phytase was given.
Asunto(s)
6-Fitasa , Química , Genética , Metabolismo , Sustitución de Aminoácidos , Aspergillus fumigatus , Genética , Biocatálisis , Electroforesis en Gel de Poliacrilamida , Proteínas Fúngicas , Química , Genética , Metabolismo , Concentración de Iones de Hidrógeno , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Proteínas Mutantes , Genética , Metabolismo , Mutación , Pichia , Genética , Reacción en Cadena de la Polimerasa , Conformación Proteica , Ingeniería de Proteínas , Métodos , Proteínas Recombinantes , Metabolismo , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
A gene appA encoding a novel phytase was firstly cloned from Hafnia alvei by PCR and sequenced. The gene was consisted of 1335 bp, encoding 444 amino acids. The calculated molecular weight of the mature APPA was about 45.2 kD. The gene appA was expressed in E. coli BL21 (DE3). Recombinant APPA was purified and its enzymatic properties were determined. The optimum pH for the enzyme was 4.5 and the optimum temperature was 60 degrees C. The pH stability of r-APPA is good, the relative phytase activity was above 80% after treated in buffers of pH 2.0-10.0. The specific activity of r-APPA is 356.7 U/mg, and the Km value was 0.49 mmol/L and Vmax of 238 U/mg. The enzyme showed resistance to pepsin and trypsin treatment.
