ABSTRACT
In the present study, two new trinor-guaiane sesquiterpenes, named clavuridins B (1), and A (2), along with three known sesquiterpenes (3-5), were isolated from the Xisha soft coral Clavularia viridis. Their structures and absolute configurations were determined on the basis of spectroscopic analysis, X-ray diffraction analysis with Cu Kα radiation and by comparison with related model compounds. Compounds 1 and 3-5 were evaluated for their cytotoxic activity.
Subject(s)
Animals , Anthozoa , Chemistry , Biological Products , Chemistry , Pharmacology , Magnetic Resonance Spectroscopy , Molecular Structure , Sesquiterpenes, Guaiane , Chemistry , PharmacologyABSTRACT
The argE gene from Escherichia coli coding for N-acety-L-ornithine deacetylase(NAOase), the key enzyme involved in the L-arginine biosynthesis, had been cloned in pET22b and transformed into BL21 (DE3). With 32.5% expression level in the optimal fermentation medium at 37 degrees C, most NAOase was expressed as inclusion bodies. The soluble and active proportion could be slightly increased when expressed at low temperature. The specific activity of soluble NAOase purified by Ni-NTA resin chromatography was 1193.2u/mg. The species and proportions of whole cell proteins varied with induction conditions. The inclusion bodies expressed at 37 degrees C was more pure than 22 degrees C after gradient wash with urea. Inclusion bodies could be partly refolding and reactivated by dilution and dialysis. Low protein concentration and suitable rate of oxidant/reducing agents were important to renaturation. In the optimal conditions 17.78% of Urea-denatured NAOase could be refolding and reactivated by dilution. The purified fusion protein was obtained after wash, solubilization and Ni-NTA resin affinity chromatography purification of inclusion bodies.
Subject(s)
Amidohydrolases , Chemistry , Genetics , Metabolism , Biocatalysis , Electrophoresis, Polyacrylamide Gel , Escherichia coli , Genetics , Escherichia coli Proteins , Genetics , Metabolism , Gene Expression Regulation, Bacterial , Gene Expression Regulation, Enzymologic , Inclusion Bodies , Protein Folding , Recombinant Proteins , Chemistry , Metabolism , Urea , PharmacologyABSTRACT
The kinetics of immobilized cells of Brevibacterium ammoniagenes MA-2 and Brevibacterium flavum MA-3 cells were studied. By means of both a theoretical analysis of diffusion in the gel particles and an experimental determination of apparent kinetic parameters, the intrinsic kinetic parameters of immobilized cells of B. ammoniagenes MA-2 and B. flavum MA-3 cells were obtained.
Subject(s)
Brevibacterium , Metabolism , Physiology , KineticsABSTRACT
In order to change the situations such as students’passivity and low enthusiasm in the traditional experimental teaching of Microbiology and improve students’comprehensive qualities,exploration and attempt on experimental teaching reforms including teaching contents,teaching modes,laboratory management and evaluation system of examination were done.Teaching practices showed that the normalized ex- periment syllabus based on the correct orientation of experimental teaching of Microbiology,the actualization of teaching mode of basic skill training-integrated experiment-designed experiment and the management of opening laboratory were effective measures in improving experimental teaching of Microbiology.
ABSTRACT
The isolated 24 strains-producing hydantoinase & carbamoylase were first identified by Biolog microbial identification system and 16S rDNA sequence analysis.The results suggested that the hydantoinase & carbamoyalse-producing bacteria belonged to Bacillus,Geobacillus,Brevibacillus,Aneurinibacillus,Microbacterium,Pseudomonas,Kurthia and Empedobacter,and so on.Especially,Kurthia and Empedobacter were new hydantoinase & carbamoylase-producing genera.Furthuremore,it was found that D-hydatoinase & carbamoyalse-producing bacteria belonged to Pseudomonas and Agrobacterium,while most of L-hydantoinase & carbamoyalse-producing bacterial belonged to Bacillus,Geobacillus and Microbacterium.The distribution feature of D-hydantoinase & carbamoyalse-producing bacteria and L-hydantoinase & carbamoyalse-producing bacteria showed some genera tendency.This research work will provide the biomaterial of different hydantoinase and carbamoylase and contribute to study the structure and function,molecular evolution of the two enzymes.