Metagenomic cosmid libraries containing 1.26 x 10(5) clones, covering about 4.8 x 10(6) kb metagenomic DNA of uncultured microorganisms from the contents of buffalo rumens were constructed, and 118 independent clones expressing beta-glucosidase activity were isolated from the libraries. Screening of these clones showed that eight clones expressed relatively higher beta-glucosidase activity at pH 5.0 and 37 degrees C. One out of the eight clones was subcloned. Sequencing analysis showed that an open reading frame (ORF) of 2223 bp, termed umcel3G, potentially encodes a beta-glucosidase. The encoded product shared highest homology with a beta-glucosidase from Bacillus sp. at 60% identity and 73% similarity. The umcel3G was over-expressed in Escherichia coli and the size of the translated product Umcel3G on SDS-PAGE was in agreement with the predicted molecular mass. Zymogram analysis showed that Umcel3G exhibited beta-glucosidase activity, confirming that this ORF encodes a beta-glucosidase. The Umcel3G, purified with Ni-NTA column, exhibited optimal activity at pH 6.0-6.5 and 45 degrees C. Certain ions such as Ca2+, Zn2+ had significant positive effect on the activity of Umcel3G. However, some ions such as Fe3+, Cu2+ gave significant inhibitory effect on the enzyme. The Ni-NTA purified recombinant beta-glucosidase Umcel3G had a specific activity of 22.8 IU/mg at pH4.5, 35 degrees C and at the presence of 5 mmol/L Ca2+, indicating that this enzyme has potential applications in the fermentative production of ethanol by simultaneous saccharification and cofermentation (SSCF) of lignocelluloses.
Animals ; Bacteria ; enzymology ; genetics ; Buffaloes ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Open Reading Frames ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; metabolism ; Rumen ; microbiology ; beta-Glucosidase ; biosynthesis ; genetics ; isolation & purification

Threatened abortion is a common disease of obstetrics and gynecology and one of the diseases responding specifically to traditional Chinese medicine （TCM）. The China Association of Chinese Medicine organized experts in TCM obstetrics and gynecology， Western medicine obstetrics and gynecology， and pharmacology to deeply discuss the advantages of TCM and integrated Chinese and Western medicine treatment as well as the medication plans for threatened abortion. After discussion， the experts concluded that chromosome， endocrine， and immune abnormalities were the key factors for the occurrence of threatened abortion， and the Qi and blood disorders in thoroughfare and conception vessels were the core pathogenesis. In the treatment of threatened abortion， TCM has advantages in preventing miscarriages， alleviating clinical symptoms and TCM syndromes， relieving anxiety， regulating reproductive endocrine and immune abnormalities， personalized and diversified treatment， enhancing efficiency and reducing toxicity， and preventing the disease before occurrence. The difficulty in diagnosis and treatment of threatened abortion with traditional Chinese and Western medicine lies in identifying the predictors of abortion caused by maternal factors and the treatment of thrombophilia. Recurrent abortion is the breakthrough point of treatment with integrated traditional Chinese and Western medicine. It is urgent to carry out high-quality evidence-based medicine research in the future to improve the modern diagnosis and treatment of threatened abortion with TCM.