The diatom Nitzschia laevis is a good alternative source of eicosapentaenoic acid (EPA). Besides strategies for high cell density culture, EPA productivity may be further improved by herbicides. The effect of the herbicide quizalofop-p-ethyl on the growth and EPA production was studied in this paper. As the solvent of the herbicide, DMSO was proved to inhibit the growth and EPA production of N. laevis. The concentration of DMSO in the medium should not exceed 0.2%. Quizalofop-p-ethyl could cause morphology damage to the N. laevis cells. With the increasing concentration of quizalofop-p-ethyl from 0 mmol/L to 0.4 mmol/L, the dry cell weight production decreased, while at the same time, the lipid content of the dry cell mass increased. When treated with 0.1 mmol/L quizalofop-p-ethyl, the EPA content increased from 3.00% to 3.58% (of dry cell weight, DW), and the proportion of EPA (20:5) in total fatty acids (TFA) increased from 25.15% to 32.88% . These results indicated that the herbicide quizalofop-p-ethyl could stimulate the accumulation of EPA; therefore it might be useful for selecting algae colonies that overproduce EPA.
Culture Media ; Culture Techniques ; Diatoms ; growth & development ; metabolism ; Eicosapentaenoic Acid ; biosynthesis ; Herbicides ; pharmacology ; Propionates ; pharmacology ; Quinoxalines ; pharmacology

This study was carried out in adult ferret cardiomyocytes to investigate the effects of the n-3 polyunsaturated fatty acids (PUFAs) on voltage-gated K(+) currents. We report that the two outward K(+) currents: the transient outward K(+) current (I(to)) and the delayed rectifier K(+) current (I(K)), are both inhibited by the n-3 PUFAs, while the inwardly rectifying K(+) current (I(K1)) is unaffected by the n-3 PUFAs. Docosahexaenoic acid (C22:6n-3, DHA) produced a concentration dependent suppression of I(to) and I(K) in adult ferret cardiomyocytes with an IC(50) of 7.5 and 20 micromol/L, respectively; but not I(K1). In addition, eicosapentaenoic acid (C20:5n-3, EPA) had the effects on the three K(+) channels similar to DHA. Arachidonic acid (C20:4n-6, AA) at 5 or 10 micromol/L, after an initial inhibitory effect on I(K), caused an activation of I(K),AA which was prevented by pretreatment with indomethacin, a cyclooxygenase inhibitor. Monounsaturated and saturated fatty acids, which are not antiarrhythmic, lack the effects on these K(+) currents. Our results demonstrate that the n-3 PUFAs inhibit cardiac I(to) and I(K) with much less potency compared to their effects on cardiac Na(+) and Ca(2+) currents as we reported previously. This inhibition of the cardiac ion currents by the n-3 PUFAs may contribute to their antiarrhythmic actions.
Animals ; Arachidonic Acid ; pharmacology ; Docosahexaenoic Acids ; pharmacology ; Dose-Response Relationship, Drug ; Eicosapentaenoic Acid ; pharmacology ; Ferrets ; Myocytes, Cardiac ; drug effects ; metabolism ; Potassium Channels, Voltage-Gated ; metabolism

OBJECTIVE: To explore the correlation between the eicosapentaenoic acid(EPA), docosahexaenoic acid (DHA) and the aggressive behavior in mice. METHODS: Seventy-two male Kunming mice were divided into control group, fish oil group, simvastatin group and aggressive reference group randomly. The control group, fish oil group and simvastatin group were given normal saline, fish oil and simvastatin by irrigation respectively for 3 months consecutively, each mouse was raised isolatedly. The latent period of assault, the frequencies of tail swing and assault, and the cumulative time of assault were recorded at the beginning and the end of the intervention. Finally, the EPA and DHA in brain were analyzed by gas chromatography-mass spectrometry (GC-MS). The aggressive reference group was raised without intervention and was evaluated as aggressive reference only. RESULTS: (1) Before intervention, the latent period of assault, the frequencies of tail swing, the frequencies of assault, and the cumulative time of assault were not significantly different from each other group. After intervention, the differences were significant (P<0.05). (2) After the intervention, the content of EPA and DHA in mice brain was the most in the fish oil group, and the least in the simvastatin group. (3) The content of EPA was negatively related with the four indexes (P<0.05) before and after the intervention. The content of DHA was negatively related with the frequencies of tail swing and assault (P<0.05). CONCLUSION There is a correlation between the EPA, DHA and aggressive behavior in mice under stress.
Aggression/physiology* ; Animals ; Behavior, Animal/physiology* ; Brain/metabolism* ; Docosahexaenoic Acids/metabolism* ; Eicosapentaenoic Acid/metabolism* ; Fatty Acids, Omega-3/metabolism* ; Fish Oils/pharmacology* ; Gas Chromatography-Mass Spectrometry ; Male ; Mice ; Random Allocation ; Simvastatin/pharmacology*

The relationship between omega-3 polyunsaturated fatty acids (PUFAs) and violent-aggressive behavior has been payed attention since 1980s. Their correlation was explored by many epidemiological investigations, and the effect of PUFAs on prevention or reduction of violent-aggressive behavior in different groups were also affirmed by some intervention studies. This article summarized the previous studies and reviewed the history of epidemiological or intervention studies on PUFAs and its relationship with violent-aggressive behavior. It also presented the possible influencing factors in these studies and possible mechanisms.
Aggression ; Animals ; Dietary Fats, Unsaturated/pharmacology* ; Dietary Supplements ; Docosahexaenoic Acids/pharmacology* ; Eicosapentaenoic Acid/pharmacology* ; Fatty Acids, Omega-3/pharmacology* ; Fatty Acids, Omega-6/pharmacology* ; Fishes ; Folic Acid/metabolism* ; Humans ; Hydroxyindoleacetic Acid/metabolism* ; Norepinephrine/metabolism* ; Risk Factors ; Serotonin/metabolism* ; Violence/prevention & control*

OBJECTIVETo investigate the change in the expression of tight junction protein ZO-1 in intestinal epithelial cells (Caco-2 cells) and the protective effect of eicosapentaenoic acid (EPA) after adherent-invasive Escherichia coli (E.coli) LF82 infection.

METHODSThe Caco-2 cell line was used to establish an in vitro model of tight junction of intestinal epithelial cells. Caco-2 cells were divided into EPA treatment groups (0, 25, 50, 100, and 200 μmol/L EPA) and EPA (0, 25, 50, 100, and 200 μmol/L EPA)+E.coli LF82 treatment (0, 6, and 12 hours) groups. A microscope was used to observe the morphological characteristics of the cells. MTT assay was used to determine the cell growth curve. The activity of alkaline phosphatase (ALP) at both sides of the cell membrane was compared to evaluate the Caco-2 cell model. MTT assay and flow cytometry were used to investigate the effects of different concentrations of EPA on the survival rate and apoptosis rate of Caco-2 cells. RT-qPCR was used to measure the mRNA expression of ZO-1 in Caco-2 cells after EPA and/or E.coli LF82 treatment. ELISA was used to measure the change in the level of tumor necrosis factor-α (TNF-α) in culture supernatant.

RESULTSAfter EPA treatment (25 and 50 μmol/L), the proliferation of Caco-2 cells was induced in a dose-dependent manner. The survival rates of the cells were significantly higher than those in the control group (P<0.05). The EPA treatment (100 and 200 μmol/L) groups had a significant inhibitory effect on the proliferation of Caco-2 cells in a dose-dependent manner. The survival rates of the cells were significantly lower than those in the control group (P<0.05). The EPA treatment (100 and 200 μmol/L) groups had a significant increase in cell apoptosis rate compared with the control group (P<0.05). The 6- and 12-hour E.coli LF82 treatment groups had decreasing mRNA expression of ZO-1 in Caco-2 cells over the time of treatment and had significantly lower mRNA expression of ZO-1 than the untreated group (P<0.05). The Caco-2 cells treated with E.coli LF82 and 25 or 50 μmol/L EPA for 6 or 12 hours showed an increase in the mRNA expression of ZO-1 with the increasing concentration of EPA, as well as significantly higher mRNA expression of ZO-1 than the Caco-2 cells treated with E.coli LF82 alone (P<0.05). The Caco-2 cells treated with E.coli LF82 alone for 6 or 12 hours had increasing secretion of TNF-α over the time of treatment and had significantly higher secretion than the untreated Caco-2 cells (P<0.05). The Caco-2 cells treated with E.coli LF82 and 25 or 50 μmol/L EPA for 6 or 12 hours showed a reduction in the secretion of TNF-α with the increasing concentration of EPA and had significantly lower secretion than the Caco-2 cells treated with E.coli LF82 alone (P<0.05).

CONCLUSIONSEPA can effectively prevent the destruction of tight junction of intestinal epithelial cells induced by E.coli LF82 infection and inhibit the secretion of inflammatory factors. Therefore, it has a certain protective effect on intestinal mucosal barrier.

Apoptosis ; drug effects ; Caco-2 Cells ; Eicosapentaenoic Acid ; pharmacology ; Escherichia coli ; pathogenicity ; Humans ; Intestinal Mucosa ; metabolism ; microbiology ; RNA, Messenger ; analysis ; Tight Junctions ; drug effects ; Tumor Necrosis Factor-alpha ; secretion ; Zonula Occludens-1 Protein ; genetics

OBJECTIVETo study the effect of combination of eicosapentaenoic acid (EPA) and retinoic acid (RA) on the proliferation and differentiation of HL-60 cells and its mechanisms.

METHODSMTT was used for cell proliferation analysis, NBT reduction experiment for cell differentiation, reverse transcriptase polymerase chain reaction (RT-PCR) for retinoblastoma (RB) mRNA expression, and Western blot for RB protein (PRB) expression.

RESULTSThe proliferation inhibition rates were 35.74%, 24.38% and 42.75% for RA, EPA and combination of EPA and RA. NBT reduction experiments showed that the differentiation induced by EPA and RA was 5.9 times, and by RA was 2.6 times the capacity of the control. The RB mRNA and PRB expression were not changed by EPA, but significantly decreased by the combination of EPA and RA. Moreover, the dephosphorylation rate of PRB was increased by the treatment with EPA or/and RA.

CONCLUSIONThe changes of RB expression and PRB phosphorylation may be one of the mechanisms of the synergistic effects of EPA and RA on the HL-60 cell proliferation and differentiation.

Antineoplastic Agents ; pharmacology ; Blotting, Western ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; Drug Synergism ; Eicosapentaenoic Acid ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; HL-60 Cells ; Humans ; RNA, Messenger ; drug effects ; genetics ; metabolism ; Retinoblastoma Protein ; drug effects ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tretinoin ; pharmacology