ABSTRACT
<p><b>OBJECTIVE</b>Investigating the antioxidant activities of water and ethanol extracts of natural Cordyceps sinensis and Cordyceps militaris and their fermentation preparations.</p><p><b>METHOD</b>The samples were tested through 6 assays: inhibition ability of linoleic acid oxidation; scavenging activity of DPPH, hydrogen peroxide, hydroxyl radical and superoxide anion; and metal chelating activity.</p><p><b>RESULT</b>Samples showed different antioxidant ability, and there was not an extract that exhibited high activity in all assays; however, water extract of natural C. militaris could be regarded as the most powerful antioxidant among 8 samples. It had high activity in inhibition of linoleic acid oxidation, chelating metal ions, and scavenging DPPH and hydroxyl radical. The research also indicated that the contents of phenolic compounds in water and ethanol extracts of natural and cultured Cordyceps sp. had huge difference.</p><p><b>CONCLUSION</b>Natural Cordyceps sp. and its fermentation preparations could be used as potential natural antioxidants. The fermented process affected the antioxidant ability of cultured Cordyceps sp., and the antioxidant activity of both natural and cultured Cordyceps sp. did not significantly related with the quantity of phenolics.</p>
Subject(s)
Antioxidants , Pharmacology , Chelating Agents , Pharmacology , Cordyceps , Chemistry , Metabolism , Ethanol , Fermentation , Flavonoids , Metabolism , Free Radical Scavengers , Pharmacology , Linoleic Acid , Metabolism , Materia Medica , Pharmacology , Oxidation-Reduction , Phenols , Metabolism , PolyphenolsABSTRACT
EC-SOD inclusion bodies was refolded on column using metal (Ni) affinity chromatography, based on the metal-binding property of His-tag. The effect of protein amount, urea removal speed and temperature on refolding was observed. We compared the different efficiency purified with Ni-sepharose and Heprain-sepharose affinity chromatography, and studied the stability of the refolded proteins. The results indicate that the inclusion bodies can be renatured with Ni-sepharose affinity chromatography. The increase of the protein amount and urea removal rate , the lower of the renaturation efficiency. Higher temperature was benefit to protein renaturation. Both the Ni-sepharose and Heprain-sepharose affinity column can be used to purified the refolded proteins, but purified by Heprain-sepharose affinity column the protein had higher activity. The activity of renatured protein was stable in 10 ℃～50℃,when pH10 its stability was lower significantly. In denaturating solution the stability of renatured protein was low.
ABSTRACT
The effect of addition nucleotides on heparinase production by Flavobacterium heparinum was reseached. The result indicated that addition of nucleotides cause different effects on heparinase production depend on its addi ng mode, single kind of nucleotide would restrain, but multiplex promote. The s trongest promotion happened when the propotion of nucleotides was consistent wit h the nucleic acids of heparinase mRNA. HPLC result confined the entrance of nu cleoides to the bactera cell. And it also suggested the synthesis metabolic of nucleic acids in F.heparinum was imbalance, there always be higher lever of purin nucleoides. L-Asp was added to medium culture to enhance pyridine nucle oides thynesis in order to improve the enzyme production ,which has been affecte d by the imbalance of nucleoides.
ABSTRACT
Genes related to trehalose biosynthesis from a bacterial strain Micrococcus luteus which can convert partially hydrolyzed starch into trehalose were cloned.Full sequence of gene (MtreY) encoding trehalose maltooligosyl trehalose synthase (MTSase) and partial sequence of gene (MtreZ) encoding maltooligosyl trehalose trehalohydrolase (MTHase) were got using PCR combined non-random shotgun method.Sequence analysis of MtreY predicts a 2370bp open reading frame encoding a protein of 790 amino acids with a predicted molecular weight of 86734 Da.Homologous analysis shows that this new gene has the same conservative motifs with ?-amylase family enzymes.The MtreY gene was expressed in E.coli, and the expression product has the anticipative enzyme activity.