Cloning, expression and characterization of a new endo-β-N-acetylglucosaminidase from Streptomyces alfalfae / 生物工程学报

Endo-β-N-acetylglucosaminidase is used widely in the glycobiology studies and industries. In this study, a new endo-β-N-acetylglucosaminidase, designated as Endo SA, was cloned from Streptomyces alfalfae ACCC 40021 and expressed in Escherichia coli BL21 (DE3). The purified recombinant Endo SA exhibited the maximum activity at 35 ºC and pH 6.0, good thermo/pH stability and high specific activity (1.0×10⁶ U/mg). It displayed deglycosylation activity towards different protein substrates. These good properties make EndoSA a potential tool enzyme and industrial biocatalyst.

"Discussion on Theoretical Connotation of ""Spleen Taking Charge of Energy of Long Summer"" in Traditional Chinese Medicine" / 世界科学技术-中医药现代化

After analyzing current different understandings on the theory of spleen taking charge of energy of long summer, the author put forward the essential connotation that the spleen is a self-balanced regulation system based on time, and the spleen mainly regulates the body in long summer. The spleen is exteriorly-interiorly related to the stomach. The spleen governs ascending and the stomach governs descending, which actually summarizes the function of the whole digestive system. The spleen and stomach co-keep the self-balanced condition for the body, through the coordination of receiving and transportation, ascending and descending, dryness and dampness. The spleen is respon-sible for transportation and transformation, ascending of the clear, with a preference for dryness and aversion to dampness, which is regarded as Taiyin wet earth, corresponding with dampness in the long summer. The stomach governs receiving and descending, with a preference for moistness and aversion to dryness, which is considered to be the Y angming dry earth. In the long summer, spleen deficiency due to dampness retention may lead to hypo-func-tions of transporting and transforming, ascending of the clear; stomach excess thanks to the help of moistness and heat may lead to relative hyper-functions of receiving and decomposing food, as well as descending. The functional condition of spleen deficiency and stomach excess duo to abundant dampness in the long summer plays a dominant role in regulation on their own system and other four zang-organs; in other seasons, the functions of spleen and stomach are in a subordinate state assisting or inhibiting other four zang-organs, in pace with time, to keep balanced condition for the body, through their characteristics of nourishing and transforming. Due to spleen deficiency and stomach excess in the long summer, manifestations of the body are hyper-function of digestion and hypo-function of absorption, and may easily lead to problems in the digestive system, such as abdominal distension and loose stool. Correct understanding on the essential connotation of spleen taking charge of energy of long summer has an impor-tant significance on the pathology, diagnosis, prevention, healthcare and treatment of seasonal attacks in the digestive system.