Surface charge engineering of Thermomyces lanuginosus lipase improves enzymatic activity and biodiesel synthesis.

OBJECTIVES: This study was aimed at engineering charged residues on the surface of Thermomyces lanuginosus lipase (TLL) to obtain TLL variant with elevated performance for industrial applications. RESULTS: Site-directed mutagenesis of eight charged amino acids on the TLL surface were conducted and substitutions on the negatively charged residues D111, D158, D165, and E239 were identified with elevated specific activities and biodiesel yields. Synergistic effect was not discovered in the double mutants, D111E/D165E and D165E/E239R, when compared with the corresponding single mutants. One TLL mutant, D165E, was identified with increased specific activity (456.60 U/mg), catalytic efficiency (kcat/Km: 44.14 s-1 mM-1), the highest biodiesel conversion yield (93.56%), and comparable thermostability with that of the TLL. CONCLUSIONS: Our study highlighted the importance of surface charge engineering in improving TLL activity and biodiesel production, and the resulting TLL mutant, D165E, is a promising candidate for biodiesel industry.

The anatomy for retroperitoneal laparoscopic splanchnicectomy / La anatomía de la esplacnicectomía laparoscópica retroperitoneal

Greater splanchnic nerves (GSNs) and lesser splanchnic nerves (LSNs) are the dominant nerves in the pain of advanced cancer patients, which provides the base of retroperitoneal laparoscopic splanchnicectomy. We dissected 25 cadavers to provide anatomic basis for the surgery. Most GSNs entered the abdominal cavity close to the medial crus of the diaphragm while most LSNs the middle one. The number of the branch varies from 1 (which was 80 %) ­ 3. The abdominal segment length of LSNs and GSNs was 26 mm and 20 mm respectively. The mean diameter of the nerves was about 2 mm. The laparoscope was put through abdominal wall beneath the 12th rib at the posterior axillary line, best angles and distances for the surgery were 50 ° and 80-110 mm respectively. The anatomic parameters of splanchnic nerves in the abdominal cavity as well as the angle and distance for the retroperitoneal laparoscopic splanchnicectomy and the anatomic landmarks were presented by the study. Besides the advantages of small incision, less pain and quick recovery, the anatomic parameters provided a practicable approach for the retroperitoneal laparoscopic splanchnicectomy.

Los nervios esplácnicos mayores (NEM) y los nervios esplácnicos menores (NEm) son los nervios dominantes en el dolor de los pacientes con cáncer avanzado, que proporciona la base de la esplacnicectomía laparoscópica retroperitoneal. Se disecaron 25 cadáveres para proporcionar base anatómica para la cirugía. La mayoría de los NEM entraron en la cavidad abdominal cerca del pilar medial del diafragma, mientras que la mayoría de los Nem lo hicieron cerca del pilar medio. El número de ramas varía de 1 (que era del 80 %) - 3. La longitud del segmento abdominal de NEm y NEM fue de 26 mm y 20 mm, respectivamente. El diámetro medio de los nervios era de aproximadamente 2 mm. El laparoscopio se colocó a través de la pared abdominal debajo de la 12 costilla en la línea axilar posterior, los mejores ángulos y distancias para la cirugía fueron de 50° y 80-110 mm, respectivamente. Los parámetros anatómicos de los nervios esplácnicos en la cavidad abdominal, así como el ángulo y la distancia para la esplacnicectomía laparoscópica retroperitoneal y los puntos de referencia anatómicos fueron presentados por el estudio. Además de las ventajas de la incisión pequeña, menos dolor y recuperación rápida, los parámetros anatómicos proporcionaron un enfoque práctico para la esplacnicectomía laparoscópica retroperitoneal.