Nitrogen source is one of the important factors that affect the microalgae growth and lipid accumulation. We studied the effects of various nitrogen sources (i.e. NaNO3, CO(NH2)2, NH4Cl and CH3COONH4) and amount on the growth density, lipid yield, and eicosapentaenoic acid (EPA) content of Nannochloropsis oculata by single factor experimental method. The results show that N. oculata preferred NH4+ as nitrogen source rather than NO3- and CO(NH2)2. NH4+ could promote the growth and lipid accumulation of N. oculata. With the increase of nitrogen concentration, the biomass and the content of polyunsaturated fatty acid (PUFA) increased, but the content of lipid decreased. CH3COONH4 was the most suitable for growth, accumulation of lipid and EPA of N. oculata among the four investigated nitrogen sources. The optimal concentration was 5.29 mmol/L.
Eicosapentaenoic Acid ; metabolism ; Lipids ; biosynthesis ; isolation & purification ; Microalgae ; growth & development ; metabolism ; Nitrogen ; analysis ; metabolism ; Stramenopiles ; growth & development ; metabolism

BACKGROUND:The oxygen free radicals and apoptosis play an important role in limb ischemia/reperfusion injury, so we can al eviate limb ischemia/reperfusion injury by inhibiting the production of oxygen free radicals and apoptosis.
OBJECTIVE:To discuss the application and effect of edaravone on limb ischemia/reperfusion injury in rats.
METHODS:Of the 30 female Sprague-Dawley rats, 20 rats were randomly selected to make models of limb ischemia/reperfusion injury by ligating the root of right lower limb with a self-made bal oon cuff at 40 kPa pressure to block blood flow for 4 hours and reperfusing. After success model establishment, they were randomly assigned to two groups. In the edaravone perfusion group, edaravone 3 mg/kg was injected via the left femoral vein at 5 minutes before reperfusion. In the model group and normal group (the remaining 10 rats), an equal volume of physiological saline was given at the same time point. At 24 hours after reperfusion, the right anterior tibial muscle of each group was removed and these ultrastructural changes were observed by transmission electron microscope. Bcl-2 mRNA and Bax mRNA of rat anterior tibial muscle of each group were semiquantitatively detected with the RT-PCR and the ratio of bcl-2/bax was calculated.
RESULTS AND CONCLUSION:(1)Electron microscope results:compared with the model group, the muscle fibers were neater;the M line and the N line were clearer;the swel ing of mitochondria was al eviated;the numbers of mitochondria and mitochondrial crista were also increased in the edaravone perfusion group. (2)RT-PCR results:At 24 hours after reperfusion, the relative expression of bcl-2 mRNA and the ratio of bcl-2 mRNA to bax mRNA in right anterior tibial muscle were lower in the model group compared with the edaravone perfusion group (P<0.05). However, relative expression of bax mRNA was greater in the model group than that in the edaravone perfusion group, which were both higher than the normal group (P<0.05). Results indicated that the free radical scavenger edaravone relieved limb ischemia/reperfusion injury by improving the mitochondrial ultrastructure and promoting expression of bcl-2 mRNA and inhibiting expression of bax mRNA, and could provide a new choice for the treatment of limb ischemia/reperfusion injury.