ABSTRACT
Docosahexaenoic acid (DHA) has many unique physiological functions such as promoting the development of brain and retina in infants. Therefore, it is widely applied to food, pharmacy, breeding and other industries. To obtain engineered strains of Aurantiochytrium limacinum SR21 suitable for industrial application with increased lipid and DHA production, we designed a simple, fast, accurate and high-throughput screening method based on Nile red staining of oil droplets. First, ultraviolet C (UVC) mutagenesis was used to generate a random mutant library of A. limacinum. Second, screening conditions were optimized including staining conditions of Nile red and the sorting criterion. Thereby, three putative high-lipid mutants (D03432, D05106 and D01521) were selected from the mutant library containing 3 648 mutated clones. The three mutants grew faster and produced higher amounts of lipids and DHA compared to wild type (WT). In 100 mL cultures, the lipid content of D03432 and D05106 mutants reached 64.74% and 63.13% of dry cell weight respectively, whereas the wild strain exhibited only 43.19%. DHA yield in these two mutants were even 2.26-fold and 2.37-fold higher than that of the wild strain. Experiment with 5 L fermentor further confirmed that D03432 and D05106 mutants had better performance than the wild strain on DHA yield (45.51% and 66.46% more than that of the wild strain, respectively), and demonstrated their high potential for industrial application. This work not only generated several high-DHA content mutants with high potential for industrial use, but also provided vital guidance for high-throughput screening of lipid hyper-accumulating mutants in other oil-producing microorganisms.
Subject(s)
Bioreactors , Docosahexaenoic Acids , Mutagenesis , Staining and Labeling , StramenopilesABSTRACT
Objective To investigate the effect of docosahexaenoic acid (DHA) combined with cyclooxygenase-2 (COX-2) selective inhibitor NS-398 on the apoptosis of cholangiocarcinoma QBC939 cells and the mechanism.Methods In vitro,cholangiocarcinoma QBC939 cells were treated with 0,15,30,45,60 and 75 μg/ml DHA with 0,25,50,100,150 and 200 μmol/L NS-398,respectively.The absorbances of the QBC939 cells were measured by CCK8 and its growth inhibition ratios were analyzed.Flow cytometry was applied to detect cell apoptosis.The level of β-catenin and COX-2 mRNA and protein were measured by real-time PCR,immunocytochemistry and enzyme-linked immunoadsordent assay,respectively.Results DHA combined with NS-398 could significantly suppress the growth of QBC939 cells (P ＜ 0.05).When the concentration of DHA went up to 45 μg/ml and NS-398 was 100 μmol/L,the relative growth inhibition rate of QBC939 cells was 90.0％.If the concentrations were increased,the result showed no significant differences.Furthermore,flow cytometry analysis indicated that DHA combined with NS-398 could induce QBC939 cells apoptosis at the early stage,and the apoptosis rate was significantly different between the experimental and control groups (P ＜ 0.01).Real-time PCR showed low β-catenin and COX-2 expression in QBC939 cells disposed by DHA combined with NS-398,and their expression were significantly different between the experimental and control groups (P ＜ 0.01).Immunocytochemistry and ELISA demonstrated that DHA combined with NS-398 could decrease β-catenin and COX-2 protein expression in QBC939 cells.Conclusion DHA combined with NS-398 induced apoptosis and inhibited proliferation of cholangiocarcinoma cells QBC939 in vitro through targeting β-catenin and COX-2.
ABSTRACT
OBJECTIVES: This research aims to study the effect of omega-3 fatty acid as an adjunct to pharmacologic treatment for major depressive disorder occurring in-out patients aged 18-65 years old in a private tertiary hospital of Metro Manila who will receive pharmacologic maintenance antidepressant therapy. With the knowledge that this is a pilot study for Filipinos, the endpoint will be geared towards determining the feasibility of actually prescribing a dietary supplement in the form of omega-3 to further improve the depressive condition of our patients.METHODOLOGY: Patients with a current diagnosis of major depressive disorder, based on Hamilton Depression Rating Scale score of 14-18 or more, which is considered as moderate depression were observed for 4 weeks. The study design was a 4-week, double-blind addition of omega-3 or placebo to ongoing antidepressant therapy. Patients were required to continue their current antidepressant treatment at the same dose they were receiving when they entered the study. Patients were required to continue their current antidepressant treatment at the same dose they were receiving when they entered the study. Patients who were included in the study had been receiving their antidepressant medication for at least three weeks at the therapeutic dose.RESULTS: Twenty-four patients participated. Eighteen were women, and six were men. Their mean age was 39.7 (range=18-63). The mean reduction of HAM-D scale score in patients taking omega-3 was 12.17 points, compared with 9.58 in patients receiving placebo.CONCLUSION: This comparison in the reduction of scores was insignificant. There was no observable significant trends toward the superiority of omega-3 supplements over placebo in reducing depressive symptoms.
Subject(s)
Humans , Male , Female , Middle Aged , Adult , Young Adult , Adolescent , Fatty Acids , Depressive Disorder , Women , Men , LipidsABSTRACT
Objective To investigate the inhibitory effect of DHA and its mechanism of apoptosis induced by DHA on human gastric cancer cell SGC-7901.Methods The survival rate of tumor cells was evaluated by MTT assay,cell morphology of apoptotic cell was observed with Hoechest 33258 staining.The contents of MDA and GSH were measured respectively by TBA and DTNB assay.Flow cytometry was used to detect the rate of apoptotic cell and intracellular variation of ROS level.Results After being treated with different concentrations of DHA,the survival rate of tumor cells was decreased in a dose-dependent manner and apoptosis was induced.The morphological characterizes of apoptotic cells were chromatin condensation and formation of apoptotic bodies.Intracellular MDA content was increased in the treated cells compared with control group,whereas GSH was decreased.After treated with 80 ?mol?L-1 DHA 5 h,flow cytometic analysis showed ROS peak and NAC could block the generation of ROS.Conclusion DHA can inhibit the growth of human gastric cancer cell SGC-7901 via inducing apoptosis.The increase of lipid peroxidation production and ROS may play an important role in apoptosis of the cells.
ABSTRACT
w-3 polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA) , are essential components for the development of human brain. A fish oil product enriched with DHA (51. 65%) was used to conduct a preliminary memory study with rats employing the active avoidance test. Three doses of DHA, 1. 0 g/kg, 200 mg/kg and 40 mg/kg, were administered orally to the rats twice daily for 20 days. The results showed that there was a positive correlation between the effects on memory ability and DHA adiministration, and the effects were dose responsive. The results also showed that DHA, at 200 mg/kg, could antagonize dysmnesia caused by scopolamine and had hypermnesia effect.
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Objective To study the antitumor mechanism of DHA compound. Methods RT-PCR was used to investigate the effects of DHA compound on H-Ras and pl6 mRNA transcription in gastric adenocarcinoma. Results Compared with control, the content of H-Ras mRNA was decreased and the content of p16 mRNA was increased in gastric adenocarcinoma significantly after treated with DHA compound. Conclusion The transcription of H-Ras gene was decreased and the transcription of pl6 gene was increased in gastric adenocarcinoma after treated with DHA compound and thus the cancer cell growth was inhibited.