Mechanism of pachymic acid in the treatment of gastric cancer based on network pharmacology and experimental verification

BACKGROUND Pachymic acid(PA)is derived from Poria cocos.PA has a variety of pharmacological and inhibitory effects on various tumors.However,the mechanism of action of PA in gastric cancer(GC)remains unclear.AIM To investigate the mechanism of PA in treating GC via the combination of network pharmacology and experimental verification.METHODS The GeneCards and OMIM databases were used to derive the GC targets,while the Pharm Mapper database provided the PA targets.Utilizing the STRING database,a protein-protein interaction network was constructed and core targets were screened.The analyses of Gene Ontology,Kyoto Encyclopedia of Genes and Genomes(KEGG),and gene set enrichment analysis were conducted,and molecular docking and clinical correlation analyses were performed on the core targets.Ultimately,the network pharmacology findings were validated through in vitro cell assays,encompassing assessments of cell viability,apoptosis,cell cycle,cloning,and western blot analysis.RESULTS According to network pharmacology analysis,the core targets were screened,and the PI3K/AKT signaling pathway is likely to be the mechanism by which PA effectively treats GC,according to KEGG enrichment analysis.The experimental findings showed that PA could control PI3K/AKT signaling to prevent GC cell proliferation,induce apoptosis,and pause the cell cycle.CONCLUSION Network pharmacology demonstrated that PA could treat GC by controlling a variety of signaling pathways and acting on a variety of targets.This has also been supported by in vitro cell studies,which serve as benchmarks for further research.

Unraveling the therapeutic mechanisms of myristic acid and luteolin 7-rutinoside in oral cancer: insights from network pharmacology and molecular docking analysis

Background:The compound Luteolin-7-rutinoside(L7R)is a flavone derivative of luteolin,predominantly identified in plant species belonging to the families Asteraceae.Conversely,Myristic acid is characterized by its structure as a 14-carbon,unsaturated fatty acid.In this investigation,we endeavor to elucidate the putative mechanisms underlying the therapeutic effects of Myristic Acid and Luteolin 7-rutinoside in the context of oral cancer treatment,employing network pharmacology coupled with molecular docking methodologies.Methods:The protein targets of Myristic Acid and Luteolin 7-rutinoside were identified through a search on the Swiss Target Database.Subsequently,a compound-target network was constructed using Cytoscape 3.9.1.Targets associated with OC were retrieved from the OMIM and GeneCards databases.The overlap between compound targets and OC-related targets was determined,and the resulting shared targets were subjected to protein-protein interaction(PPI)network analysis using the STRING database.Additionally,gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were conducted on the identified targets.Molecular docking were performed to investigate the interactions between the core target and the active compound.Results:The component target network comprises 103 nodes and 102 edges.Among the proteins in the protein-protein interaction(PPI)network,those with higher degrees are TNF,PPARG,and TP53.Analysis through Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways indicates that the treatment of OC with Myristic Acid and Luteolin 7-rutinoside primarily involves the regulation of miRNA transcription and inflammatory response.The identified signaling pathways include Pathways in cancer,PPAR signaling pathway,EGFR signaling pathway,and TNF signaling pathway.Molecular docking studies reveal that Luteolin 7-rutinoside and Myristic acid exhibit higher affinity towards TNF,PPARG,TP53,and EGFR.Conclusion:This study reveals the potential molecular mechanism of Myristic Acid and Luteolin 7-rutinoside in the treatment of oral cancer,and provides a reference for subsequent basic research.

Exploring the targets and molecular mechanism of glycyrrhetinic acid against diabetic nephropathy based on network pharmacology and molecular docking

BACKGROUND Diabetic nephropathy(DN)stands as the most prevalent chronic microvascular complication of diabetes mellitus.Approximately 50%of DN patients progress to end-stage renal disease,posing a substantial health burden.AIM To employ network pharmacology and molecular docking methods to predict the mechanism by which glycyrrhetinic acid(GA)treats DN,subsequently validating these predictions through experimental means.METHODS The study initially identified GA targets using Pharm Mapper and the TCMSP database.Targets relevant to DN were obtained from the Genecards,OMIM,and TTD databases.The Venny database facilitated the acquisition of intersecting targets between GA and DN.The String database was used to construct a protein interaction network,while DAVID database was used to conducted Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis and Gene Ontology(GO)analysis.Molecular docking experiments were performed using Autodock software with selected proteins.Experimental validation was conducted using renal proximal tubular cells(HK-2)as the study subjects.A hyperglycemic environment was simulated using glucose solution,and the effect of GA on cell viability was assessed through the cell counting kit-8 method.Flow cytometry was employed to detect cell cycle and apoptosis,and protein immunoblot(western blot)was used to measure the expression of proteins of the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway and insulin resistance pathway,including insulin receptor(INSR),PI3K,p-PI3K,AKT,p-AKT,and glycogen synthase kinase-3(GSK3).RESULTS A total of 186 intersecting targets between GA and DN were identified,which were associated with 144 KEGGrelated enrichment pathways,375 GO biological process entries,45 GO cellular component entries,and 112 GO cellular function entries.Molecular docking demonstrated strong binding of GA to mitogen-activated protein kinase(MAPK)-1,SRC,PIK3R1,HSP90AA1,CASPASE9,HARS,KRAS,and MAPK14.In vitro experiments revealed that GA inhibited HK-2 cell viability,induced cell cycle arrest at the G2/M phase,and reduced apoptosis with increasing drug concentration.Western blot analysis showed that GA differentially up-regulated GSK3 protein expression,up-regulated AKT/p-AKT expression,down-regulated INSR,AKT,p-AKT,PI3K,and p-PI3K protein expression,and reduced p-PI3K/PI3K levels under high glucose conditions.CONCLUSION GA may protect renal intrinsic cells by modulating the PI3K/AKT signaling pathway,thereby inhibiting HK-2 cell viability,reducing HK-2 cell apoptosis,and inducing cell cycle arrest at the G0/G1 phase.

Higher Dietary Arachidonic Acid Levels Improved the Growth Performance, Gonad Development, Nutritional Value, and Antioxidant Enzyme Activities of Adult Sea Urchin(Strongylocentrotus intermedius)

The gonads of sea urchins(Strongylocentrotus intermedius) are characterized by high levels of arachidonic acid(ARA, 20:4 n-6) and eicosapentaenoic acid(EPA, 20:5 n-3). However, to our knowledge, little information is available regarding the physiological response of adult sea urchins to dietary ARA. In the present study, four dietary feeds were formulated with graded ARA(0, 0.5%, 1%, and 2% dry diet). Each diet was randomly allocated to three cages during a 56-day feeding experiment. The results showed that the sea urchin weight gain rate(WGR) and the gonadosomatic index(GI) significantly increased as ARA was equal to or above 1.0% of dry diet(P < 0.05). The activities of superoxide dismutase(SOD), catalase(CAT), and total anti-oxidative capacity(T-AOC) were the highest in the coelomic fluid of sea urchins that were fed diets with 1% ARA. The total essential amino acid(TEAA) and its ratio to total non-essential amino acid(TNEAA) showed a similar tendency to WGR and GI as dietary ARA increased, and the highest TEAA and TEAA/TNEAA were observed in the gonads of sea urchins that were fed diets with 1% ARA. Levels of ARA and ARA/EPA of the gonads increased while n-3/n-6 polyunsaturated fatty acid(PUFA) decreased with the increase of dietary ARA(P < 0.05). EPA in the gonads of experimental animals fed with formulated feeds showed no significant differences(P> 0.05), but was significantly lower than those fed with kelp(P < 0.05). These results suggested that relatively higher levels of ARA(1% dry diet) significantly promoted growth, gonad development, activities of antioxidant enzymes, as well as nutritional values(TEAA, TEAA/TNEAA, and PUFA) of adult S. intermedius.

Enhancement of Arachidonic Acid Production by Mortierella isabellina Through Protoplast Regeneration Mutagenesis

A developed method was used for the enhancement of arachidonic acid production by M. isabellina. An orthogonal, rotatable and central composite design was applied to determine the optimum conditions for protoplast regeneration mutagenesis. The results showed that a commixture enzyme （cellulase and glusulase） at the concentration of 4%, enzymolysis temperature at 30℃ and enzymolysis time on 7.5 h were the optimal conditions, in which the lethality of M. isabellina spores was 78.4%. After mutagenesis and re-screenings, M. isabellina mutant Y-69 was obtained. GC analysis showed that the yield of arachidonic acid by Y-69 （2.92 g. L-1） was 3.56 times higher than that of the wild-type strain （0.82 g.L-1）. Pass generation tests showed that the properties of Y-69 by mutation were readily inherited.

FATTY ACIDS PROFILE IN A HIGH CELL DENSITY CULTURE OF ARACHIDONIC ACID-RICH PARIETOCHLORIS INCISA (TREBOUXIOPHYCEAE,CHLOROPHYTA) EXPOSED TO HIGH PFD

The changes in arachidonic acid (AA) and fatty acids profiles along the growth curve of Parietochloris incisa, a coccoid snow green alga, were studied in a 2.8 cm light-path flat photobioreactor, exposed to strong photon flux density [PFD, 2400 μEmol/(m 2·s)]. Sixteen fatty acids were identified by gas chromatography showing that AA was the dominant fatty acid (33%-41%) followed by linoleic acid (17%-21%). AA content was closely investigated with respect to total fatty acids (TFA), ash free dry weight (AFDW) of cell mass as well as total culture content. These parameters were influenced significantly in a similar manner by culture growth phase, i.e., slightly decreasing in the lag period, gradually increasing in the logarithmic phase, becoming maximal at the early stationary phase, starting to decrease at the late stationary phase, sharply dropping at the decline phase. The increase in AA per culture volume during the logarithmic phase was not only associated with the increase in AFDW but also connected with a corresponding increase in AA/TFA, TFA/AFDW as well as AA/AFDW. The sharp decrease in AA content of the culture during the decline phase was mainly due to the decrease in AA/TFA, TFA/AFDW and AA/AFDW, although AFDW declined only a small extent. Maximal AA concentration, obtained at the early stationary phase, was 900 mg/L culture volume, and the average daily net increase of AA during 9 days logarithmic growth was 1.7 g/(m 2·day). Therefore, harvesting prior to the decline phase in a batch culture, or at steady state in continuous culture mode seems best for high AA production. The latter possibility was also further confirmed by continuous culture with 5 gradients of harvesting rate.

PHYSIOLOGICAL INHIBITORY EFFECT OF OCS IN ARACHIDONIC ACID-RICH PARIETOCHLORIS INCISA (TREBOUXIOPHYCEAE, CHLOROPHYTA)

Parietochloris incisa is an arachidonic acid rich snow green alga. The main physiological profiles, such as ash free dry weight (AFDW), chlorophyll, carotenoid, protein and total fatty acids (TFA), in this alga exposed to old culture supernatant (OCS) at the decline phase or its crude ethyl acetate extracts (CEAE) were investigated by using tubular photobioreactors of different diameters. Results showed that both OCS and CEAE had strong inhibitory effect on the above physiological parameters. The longer the culture was exposed to OCS and the more CEAE were added into the algal culture, the more the above physiological properties were inhibited. Arachidonic acid (AA), the dominant component of fatty acids in this alga, was also seriously inhibited with respect to total TFA, AFDW of cell mass, or culture volume, due to a probable reduction of enzymes activities catalyzing chain elongation from C18:1ω9 to AA. These results incontestably evidenced that some CEAE dissolving substances existing in OCS, like auto inhibitors, inhibited P. incisa growth through feedback. Hence, any efficient removal of auto inhibitors from algal culture to decrease their bioactivity could be good for maximal production of desired products like AA.

Functional characterization of a Δ6 fatty acid desaturase gene and its 5′-upstream region cloned from the arachidonic acid-rich microalga Myrmecia incisa Reisigl(Chlorophyta)

It is suggested that Δ6 fatty acid desaturase(FAD) plays a critical role in the biosynthesis of polyunsaturated fatty acids in plants and microalgae. But why does it adapt to the changed environments such as nitrogen starvation is seldom understood. One Δ6 FAD gene( MiD6 fad) from an arachidonic acidrich microalga M yrmecia incisa Reisigl(Chlorophyta) was first heterologously expressed in S accharomyces cerevisiae for the identification of function. The fatty acid profile of transgenic yeast detected by gas chromatography-mass spectrometry illustrated that the enzyme MiD6 FAD could convert linoleic and ?-linolenic acids to γ-linolenic and stearidonic acids, respectively, demonstrating that M iD6 fad encoded a Δ6 FAD. A 1 965-bp fragment of the cloned 2 347-bp 5′-upstream region of M iD6 fad was next subcloned and fused upstream with green fluorescent protein(GFP) gene to replace the GAL1 promoter of the vector pYES2. The generated construct was transformed into S. cerevisiae for function determination. Confocal microscopic images of the transformed line illustrated that this inserted fragment could drive GFP expression, which was further verified by fluorescence intensity quantification and Western blot analysis using antiGFP antibody. The conversion efficiency(approximately 2%-3%) of MiD6 FAD was much lower than the reported ? 3 FAD and Δ6 elongase in this microalga, suggesting that MiD6 FAD catalysed the possible ratelimiting step for ArA biosynthesis. The presence of several putative c is-acting regulatory elements in this identified promoter sheds new light on the regulation mechanism research of Δ6 FAD transcription for the ArA production in M. incisa in changing environmental factors.

Hepatitis B virus X protein promotes liver cell proliferation via a positive cascade loop involving arachidonic acid metabolism and p-ERK1/2

肝炎 B 病毒 X 蛋白质(HBx ) 在 hepatocellular 癌的发展起一个关键作用。这里，我们寻求了识别 HBx 由调停的机制肝房间增长。我们发现那 HBx upregulated cyclooxygenase-2 (COX-2 ) 的层次， 5-lipoxygenase (5 哈鱼) 和 phosphorylated 在肝房间的细胞外的调整信号的蛋白质 kinases 1/2 (p-ERK1/2 ) 。导致 HBx 的 p-ERK1/2 被 Gi/o 蛋白质，艇长或哈鱼的抑制废除。另外， HBx 增加了前列腺素 E2 (PGE2 ) 的数量，免除房间线的 leukotriene B4 (LTB4 ) 源于 hepatocytes。而且，这些释放 arachidonic 酸代谢物能激活 ERK1/2。有趣地，激活 ERK1/2 能 upregulate 以一种积极反馈方式的 COX-2 和 5 哈鱼的表示。在结论， HBx 经由包含 COX-2， 5 哈鱼，释放 arachidonic 酸代谢物， Gi/o 蛋白质和 p-ERK1/2 的一个积极反馈环提高并且维持肝房间增长。

Evaluation of the inhibitory effect of docosahexaenoic acid and arachidonic acid on the initial stage of amyloid β1-42 polymerization by fluorescence correlation spectroscopy

Amyloid β(Aβ)1-42 fibrillation is a crucial step in the development of pathological hallmarks, such as neuritic plaques and neurofibrillary tangles, of Alzheimer’s disease (AD). In this study, we evaluated the effects of free docosahexaenoic acid (DHA), an essential brain polyunsaturated fatty acid (PUFA), on the inhibition of Aβ1-42 fibrillation by fluorescence correlation spectroscopy (FCS), a technique capable of detecting molecular movements and interactions in solution. We also examined whether free arachidonic acid (AA), eicosapentaenoic acid (EPA), and metabolites of DHA, including neuroprotectin D1 (NPD1, 10S, 17S-dihydroxy-DHA), resolvin D1 (RvD1, 7S, 8R, 17S-trihydroxy-DHA), and didocosahexaenoyl glycerol (diDHA), affect Aβ1-42 polymerization. The results of the FCS study reveal that DHA and AA significantly reduced the diffusion time of TAMRA (5-carboxytetramethylrhoda-mine)-Aβ1-42 by 28% and 31%, respectively, while EPA, NPD1, RvD1, and diDHA had no effects on diffusion time. These results indicate that DHA and AA inhibited Aβ1-42 polymerization and that their inhibitory effects occurred at the initial stage of Aβ1-42 polymerization. This study will advance the research on PUFAs in preventing AD progression.

Arachidonic acid Metabolism in Galactosamine／Endotoxin Indudced Acute Liver injury in Rats

The changes of the levels of LTC4, PGI2 and TXA2 in the liver tissue in SD rats with GaIN/LPS-induced acute liver injury was studied with radioimmunoassay (RIA). As a result,12h after the administration of GaIN/LPS, serum AST (398±37u), ALT (565 ±43u) increased (P<0.001 ) and the concentration of TXA2 (12188±588pg/g· w· wt) in liver tissue increased sigiuficantly(p<0.001), while the content of LTC4 (9713± 3557ng/g·w·wt ) and PGI2 (1748±560 pg/g· w·wt) in liver tissue were not obviously changed(p>0.05) and the inflammatory changes of the pathological findings were observed. The improvement of serum ALT (300±168u)(p< 0.05) and AST(273±424 u) (P<0. 05) and histopathological damage was observed after the administration of diethylcarbamazine (DEC), a LTA4 synthesis inhibitor, the liver TXA2(12740±699) concentration significantly increased (P<0. 001), while the levels of LTC4 (8179±1653) and PGI2 (2320±630) were not obviously changed. Serum ALT (536±74u) and AST (416± 41u)(P> 0. 05) levels and histopathology did not change with administration of indomethacin, a cyclooxygenase inhibitor, but the liver LTC4 (12166±13027) contents increased (P<0.05 ) and TXA2 (1868±791) reduced significantly (P<0. 001). The present study suggests that arachidonic acid metabolism in rats with acute liver injury are significantly abnormal. Leukotrienes and thromboxane are important inflammatory mediators in the liver injury.

Mutagenesis of Arachidonic Acid-producing Mortierella Isabellina and Analyses of Δ~6-desaturase Role by qPCR

Arachidonic acid （AA or ARA）, an essential to-6 polyunsaturated fatty acid （PUFA）, can be produced by Mortierella isabellina. Mutagenesis on Mortierella isabellina As3.3410 was induced to raise ARA production. The mutant strain of YZ-124 had the highest ARA of 4.72 g. L-1, which was 5.5 times higher than that of the original strain 3.3410. mRNA expression level of △ 6- desaturase was determined in five different kinds of ARA-producing Mortierella isabellina after cultured for 7 days, and in the mutant strain YZ-124 over a 3-8 day time-course. In addition, the desaturase activity and ARA content were measured at the selected time points. The lowest expression of △6-desaturase was observed in the original strain and the highest expression in the mutant strain YZ-124, which increased with increasing time in culture. Furthermore, a positive correlation was observed between the expression levels of △6-desaturase and ARA content. Based on this, △6-desaturase played a significant role in ARA synthesis pathway in Mortierella isabellina.

Purification Process,Content Determination,Pharmacological Activity and Molecular Mechanism of Neogambogic Acid

Neogambogic acid is characterized by broad antitumor spectrum,good antitumor effect and low toxicity and side effects.This paper reviews the purification process,content determination and pharmacologic activity of neogambogic acid,in order to provide a theoretical reference for the research and application of neogambogic acid.

Research advances in phytochemistry,pharmacology and toxicology of oleanolic acid

Oleanolic acid(OA)is a pentacyclic triterpenoid chemical component that exists in natural plants with a molecular formula of C30H48O3 and a molecular weight at 456.71 g·mol-1.OA is widespread in traditional Chinese herbal medicine(Ligustri Lucidi Fructus,Achyranthis Bidentate Radix,Red Sage)and berries(blueberries,grapes).In recent years,because of the extensive pharmacological effects of OA,its advantages in disease treatment have become increasingly prominent and gradually attracted the attention of pharmaceutical researchers.OA has effective therapeutic effects on a series of chronic diseases such as inflammation,cancer,diabetes,and cardiovascular diseases through multiple signaling pathways and various targets.Especially in cancers,such as colorectal cancer,liver cancer,gastric cancer,lung cancer,breast cancer and other malignancies,OA presents substantial efficacy.However,its poor aqueous solubility,needy bioavailability,and unsatisfactory pharmacological activity excessively restrict its clinical application.More importantly,the improper utilization of OA can cause adverse reactions,toxic effects and even damage to organs in some specific situations.With the discovery of various pharmacological effects,the complex action mechanisms of OA,the continuous progress in structural modification of OA,as well as the synthesis of OA derivatives,its application is expanding gradually.Among numerous studies,there is a clear indication that OA and its derivatives,if fully developed,may provide an alternative and cheaper treatment for a variety of chronic diseases.However,the specific molecular mechanisms of OA and its derivatives as an alternative therapy and supplementary therapy for cancer,diabetes,cardiovascular disease and other chronic diseases remain to be clarified.Therefore,it is necessary to further study the pharmacokinetics,pharmacological activity,specific targets and related mechanisms of OA to lay a solid foundation for drug development and the application of OA in clinical settings.

Long-term modifications of blood pressure in normotensive and spontane-ously hypertensive rats by gene delivery of rAAV-mediated cytochrome P450 arachidonic acid hydroxylase

Arachidonic acid cytochrome P-450 (CYP) hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids (20-HETE), a biologically active metabolite, which plays an important role in the regulation of blood pressure. However, controversial results have been reported regarding the exact role of 20-HETE on blood pressure. In the present study, we used recombinant adeno- associated viral vector (rAAV) to deliver CYP 4A1 cDNA and antisense 4A1 cDNA into Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR), respectively, to investigate the effects of long-term modifications of blood pressure and the potential for gene therapy of hypertension. The mean systolic pressure increased by 14.2±2.5 mm Hg in rAAV·4A1-treated SD rats and decreased by 13.7±2.2 mm Hg in rAAV·anti4A1-treated SHR rats 5 weeks after the injection compared with controls and these changes in blood pressure were maintained until the experiments ended at 24 weeks. In 4A1 treated animals CYP4A was overexpressed in various tissues, but preferentially in the kidney at both mRNA and protein levels. In anti-4A1-treated SHR, CYP4A mRNA in various tissues was probed, especially in kidneys, but 4A1 protein expression was almost completely inhibited. These results suggest that arachidonic acid CYP hydroxy- lases contribute not only to the maintenance of normal blood pressure but also to the development of hypertension. rAAV-mediated anti4A administration strategy has the potential to be used as targeted gene therapy in human hyperten- sion by blocking expression of CYP 4A in kidneys.

Docosahexaenoic acid suppresses arachidonic acid-induced proliferation of LS-174T human colon carcinoma cells

AIM:To investigate the impact of arachidonic acid (AA) and docosahexaenoic acid (DHA) and their combination on colon cancer cell growth.METHODS:The LS-174T colon cancer cell line was used to study the role of the prostaglandin precursor AA and the omega-3 polyunsaturated fatty acid DHA on cell growth. Cell viability was assessed in XTT assays. For analysis of cell cycle and cell death,flow cytometry and DAPI staining were applied. Expression of cyclooxygenase-2 (COX-2),p21 and bcl-2 in cells incubated with AA or DHA was examined by real-time RT-PCR. Prostaglandin E2 (PGE2) generation in the presence of AA and DHA was measured using a PGE2-ELISA.RESULTS:AA increased cell growth,whereas DHAreduced viability of LS 174T cells in a time-and dose-dependent manner. Furthermore,DHA down-regulated mRNA of bcl-2 and up-regulated p21. Interestingly,DHA was able to suppress AA-induced cell proliferation and significantly lowered AA-derived PGE2 formation. DHA also down-regulated COX-2 expression. In addition to the effect on PGE2 formation,DHA directly reduced PGE2-induced cell proliferation in a dose-dependent manner. CONCLUSION:These results suggest that DHA can inhibit the pro-proliferative effect of abundant AA or PGE2.

Involvement of Oxidative Stress and Down-Regulation of Bcl-2 in Arachidonic Acid-Induced Apoptosis in HUVECs

Human umbilical vein endothelial cells （HU VECs） were treated with arachidonic acid （AA）. After 24 h exposure to AA, typical morphological changes of apoptosis were observed by Giemsa stain and transmission electron microscopy. The apoptotic ratio in HUVECs treated with 50μmol/L, 100μmol/L and 150μmol/L AA were （20.7±3.6）%, （38.6±4.3）% and （52.5±7.5） % respectively. Contrarily, low concentration of AA （425μmol/L） exerted no influence on cell viability by MTT assay. Intracellular malondialdehyde increased significantly in a dose-dependent manner upon AA treatment and for the reduced glutathione. the opposite tendency was found Western Blots show that apoplosis triggered by AA was associated with the down-regulation of Bcl-2 expression, but not with Bax and p53. Pretreatment with 50μmol/L α-tocopherol reduced AA-induced oxidative stress and apoptosis, also inhibited the dowwregulation of Bcl-2/Bax ratio. These results suggested that high concentration of free AA could induce apoptosis in HUVECs probably via oxidative stress and down-regulation of Bcl-2.

Research on Arachidonic Acid and Eicosapentaenoic Acid Anabolic Metabolism in Diasporangium sp.

The fatty acids of a strain of Diasporangium sp.had been analyzed by using GC-MS.The fatty acids of twenty mutants were determined.Based on these results,the producing of eicosapentaenoic acid(EPA)supposed via 18∶2,18∶3,20∶3,20∶4 which all belong to ω-6 fatty acids.The ω-3 desaturation was undertaken at arachidonic acid(AA).In addition,mutant strains resulted in enhanced content of AA which could get two times more than initial strain,but no compact on EPA.

Shuffling the cards in signal transduction: Calcium, arachidonic acid and mechanosensitivity

Cell signaling is a very complex network of biochemical reactions triggered by a huge number of stimuli coming from the external medium. The function of any single signaling component depends not only on its own structure but also on its connections with other biomolecules. During prokaryotic-eukaryotic transition, the rearrangement of cell organization in terms of diffusional compartmentalization exerts a deep change in cell signaling functional potentiality. In this review I briefly introduce an intriguing ancient relationship between pathways involved in cell responses to chemical agonists (growth factors, nutrients, hormones) as well as to mechanical forces (stretch, osmotic changes). Some biomolecules (ion channels and enzymes) act as "hubs", thanks to their ability to be directly or indirectly chemically/mechanically co-regulated. In particular calcium signaling machinery and arachidonic acid metabolism are very ancient networks, already present before eukaryotic appearance. A number of molecular "hubs", including phospholipase A2 and some calcium channels, appear tightly interconnected in a cross regulation leading to the cellular response to chemical and mechanical stimulations.

The Property and Application of Arachidonic Acid

Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). This paper mainly introduced the structure, distribution, source, physiologic healthcare function and application of AA.