• Journal of the Korean Society of Food Culture
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• v.20 no.4
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• pp.451-458
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• 2005

For the storaging and frying stability in soybean oil, the kind of treating antioxidants were mixed tocopherol and phosphatidyl choline(PC), phosphatidyl ethanolamine(PE), phosphatidyl inpsitol(PI), phosphatidyl serine(PS), phosphatidic acid(PA), phosphatidyl glycerol(PG), treating amounts were 0.03%, 0.05%(w/w), respectively. Acid value(AV), peroxide value(POV) and oxidative stability index(OSI) were determined during storage period at $50^{\circ}C$ in soybean oil. Antioxidation effect at frying condition was determined through changes of smoke point. The antioxidation effect according to AV change was $PA>PC>PI{\geq}PG>PS{\geq}PE$, preventing effect about POV change was PA>PG>PC>PS>PE>PI and preventing effect about OSI decreasing was PI>PC>PA>PG>PS>PE. At the result, antioxidation effect of individual phospholipid components in soybean oil was appeared different result according to determination code. Determination result of preventing effect of SP decreasing according to frying at $180^{\circ}C$ during 20 hours was PA>PC>PG>PE>PI>PS. But treating effect of mixed tocopherol in preventing effect about AV, POV was not. In the case of storage at $50^{\circ}C$ in soybean oil, mixed tocopherol was affected as a kind of pro-oxidant. In OSI had some antioxidation effect, preventing effect of SP decreasing had not. Treatment of mixed tocopherol in soybean oil was undesirable as frying oil.

• BMB Reports
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• v.45 no.1
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• pp.7-13
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• 2012

Phospholipase D (PLD), a superfamily of signaling enzymes that most commonly generate the lipid second messenger Phosphatidic Acid (PA), is found in diverse organisms from bacteria to man and functions in multiple cellular pathways. A fascinating member of the family, MitoPLD, is anchored to the mitochondrial surface and has two reported roles. In the first role, MitoPLD-generated PA regulates mitochondrial shape through facilitating mitochondrial fusion. In the second role, MitoPLD performs a critical function in a pathway that creates a specialized form of RNAi required by developing spermatocytes to suppress transposon mobilization during meiosis. This spermatocyte-specific RNAi, known as piRNA, is generated in the nuage, an electron-dense accumulation of RNA templates and processing proteins that localize adjacent to mitochondria in a structure also called intermitochondrial cement. In this review, we summarize recent findings on these roles for MitoPLD functions, highlighting directions that need to be pursued to define the underlying mechanisms.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1091-1097
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• 2002

Capacitated goat spermatozoa generated diacyl glycerol (DAG) when suspended in Krebs-Ringer bicarbonate medium and induced by progesterone or $Ca^{2+}$ ionophore A23187. We have added Sn-1-oleoyl-2-acetyl glycerol externally, to study the effect of DAG in goat sperm acrosomal exocytosis. Addition of neomycin abolished the DAG generating capacity of progesterone in a dose dependent manner, suggesting the involvement of a phosphoinositidase C activated phospholipase C system in the process. The level of increase in phosphatidic acid was considerably low and was produced well after the DAG generation thereby suggesting the involvement of a DAG kinase which phosphorylates DAG to produce PA. The inhibition of progesterone mediated effect by inhibitors of $GABA_A/Cl^{-}$ channel and $Ca^{2+}$ channels further supports the evidence that the events of binding of agonist to the receptor(s), opening of $Ca^{2+}$ channels and the activation of phospholipase C are reconciled to perform the function of acrosome reaction in capacitated goat spermatozoa.

• Bulletin of the Korean Chemical Society
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• v.13 no.4
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• pp.381-384
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• 1992

The hydrolytic susceptibility of large unilamellar vesicle (LUV) toward cabbage phospholipase D (PLD) was studied. The activity of PLD was determined by pH stat titration method. Using phosphatidylcholine LUV as substrate a pH optimum of 6.96 was observed. For maximal activity the optimal temperature of $31^{\circ}C$ and 10 mM of Ca2+ were required. The apparent Km value estimated was 2.5 mM. The hydrolytic activity of PLD toward PC LUV was somewhat high despite the absence of activator in assay system and this high susceptibility of PC LUV may be attributed to the structural properties of LUV. The effect of amphiphatic substances such as dicetyl phosphate and phosphatidic acid on the enzyme activity were also examined in mixed LUVs.

• BMB Reports
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• v.39 no.5
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• pp.626-635
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• 2006

Lysophosphatidic acid acyltransferase (LPAAT) is an intrinsic membrane protein that catalyzes the synthesis of phosphatidic acid (PA) from lysophosphatidic acid (LPA). It is well known that LPAAT is involved in lipid biosynthesis, while its role in tumour progression has been of emerging interest in the last few years. To date, seven members of the LPAAT gene family have been found in human. Here we report a novel LPAAT member, designated as LPAAT-theta, which was 2728 base pairs in length and contained an open reading frame (ORF) encoding 434 amino acids. The LPAAT-theta gene consisted of 12 exons and 11 introns, and mapped to chromosome 4q21.23. LPAAT-theta was ubiquitously expressed in 18 human tissues by RT-PCR analysis. Subcellular localization of LPAAT-theta-EGFP fusion protein revealed that LPAAT-theta was distributed primarily in the endoplasmic reticulum (ER) of COS-7 cells. Furthermore, we found that the overexpression of LPAAT-theta can induce mTOR-dependent p70S6K phosphorylation on Thr389 and 4EBP1 phosphorylation on Ser65 in HEK293T cells.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3509-3513
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• 2014

Phospholipase D (PLD) catalyzed the generation of phosphatidic acid (PA) from phosphatidylcholine (PC) at the outer layer of the vesicles prepared through layer by layer via a double emulsion technique. The generation induced a curvature change in the vesicles, which eventually led them to fuse each other. The ratio of two-fatty-acid-tail ethanolamine (PE) to one-fatty-acid-tail ethanolamine (PE) was found to acquire the condition where the mixed-phospholipid vesicles were stable identically with pure two-fatty-acid-tail PC. The effect of the outer-layer mixture on the PLD-induced vesicle fusion was investigated using the fluorescence intensity change. 8-Aminonaph-thalene-1,3,6-trisulfonic acid disodium salt (ANTS) and p-Xylene-bis(N-pyridinium bromide) (DPX) were encapsulated in the vesicles, respectively, for the quantification of the fusion. The fluorescence scale was calibrated with the fluorescence of a 1/1 mixture of ANTS and DPX vesicles in NaCl buffer taken as 100% fluorescence (0% fusion) and the vesicles containing both ANTS and DPX as 0% fluorescence (100% fusion), considering the leakage into the medium studied directly in a separate experiment using vesicles containing both ANTS and DPX. The fusion data for each composition were acquired with the subtraction of the leakage from the quenching. From the monitoring, the vesicle fusion caused by the PLD reaction seems dominantly to occur rather than the vesicle lysis, because the composition effect on the fusion was observed identically with that on the change in the vesicle structure. Furthermore, the diameter measurements also support the fusion dominancy.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.197-206
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• 1997

Purpose : Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer Process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. Materials and Methods : The reaction mixture for the PLD assay contained $0.1\;\muCi\;1,2-di[1-^{14}C]palmitoyl$ phosphatidylcholine 0.5mM phosphatidylcholine, 5mM sodium oleate, $0.2\%$ taurodeoxycholate, 50mM HEPES buffer(pH 6.5), 10mM $CaCl_2$, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cmx loom and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy. Results : Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward $\gamma-rar$ with more than two times amplification in their activities In contrast, the PLD activity of bone marrow appears to be reduced to nearly $30\%$. Irradiation effect was hardly detected in liver which showed the lowest PLD activity. Conclusion : The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation s1ron91y indicates that the PLD is closely related to the physiological function of these organs, Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell Proliferation to cell death on these organs.

• Journal of Ginseng Research
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• v.32 no.2
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• pp.107-113
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• 2008

In this study, we have investigated the effect of panaxatriol (PT) on phosphoinositides (PIS) breakdown and $Ca^{2+}$-elevation in thrombin-induced platelet aggregation. Thrombin (5U/ml), a potent platelet agonist which activates phospholipase $C_{\beta}$ via protease activated receptor (PAR), hydrolyzed PIS in platelet membrane. The phosphatidylinositol 4, 5-bisphosphate $(PIP_2)$ was hydrolyzed after 10 sec of the thrombin-stimulation, and both the phosphatidylinositol 4-monophosphate (PIP) and phosphatidylinositol (PI) were brokendown after 30 sec of the thrombin-stimulation. However, PT inhibited the thrombin-stimulated hydrolysis of $PIP_2$, PIP, and PI. On the other hand, thrombin increased the level of phosphatidic acid (PA) which is phosphorylated from diacylglycerol (DG) generated by PIS-hydrolysis. However, Pr inhibited the thrombin-increased PA level non-significantly. Thrombin increased cytosolic free $Ca^{2+}([Ca^{2+}])_i$) up to 72% as compared with control $(30.8{\pm}0.9 nM)$ in intact platelet. However, PT (100 ${\mu}g/ml$) inhibited the thrombin-elevated $[Ca^{2+}]_i$ to 100%. These results suggest that PT may have a beneficial effect on platelet aggregation-mediated thrombotic disease by inhibiting thrombin-induced platelet aggregation via suppression of the $[Ca^{2+}]_i$ level and PIS breakdown.

• Journal of the Korean Chemical Society
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• v.41 no.12
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• pp.672-676
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• 1997

Microsomal phospholipase D (PLD) in rat brain was solubilized employing 0.2 % taurodeoxycholate in high ionic strength. Phopholipase D activity was determined by measuring product phophatidic acid (PA) using isotope-labelled dipalmitoylphophatidylcholine as a substrate. The solubilized PLD showed an optimal pH of 6.5 and the highest activity at 30$^{\circ}C.$ These properties were similar to those of microsomal PLD before solubilization. The stimulatory effect of oleic acid was observed at the concentration of 4 mM. When effects of metal ions on PLD activity were examined, alkaline earth metals such as $Mg^{2+},\; Ca^{2+},\; Sr^{2+}, \;Ba^{2+}$ promoted the PA production but $Cu^{2+},\; Cd^{2+},\; Al^{3+},\; Ni^{2+},\; V^{5+}$ showed inhibitory effects.

• BMB Reports
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• v.35 no.5
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• pp.459-464
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• 2002

Fusogenic liposomes that incorporate Sendai virus envelope proteins, so-called Sendai virosomes, have been developed for in vitro and in vivo genetic modification of animal cells. In this study, several different virosomes of varying lipid compositions were formulated and their in vitro gene-transfer efficiencies compared. The virosomes were prepared by quantitative reconstitution of the Sendai envelope, fusion (F) and hemagglutinin-neuraminidase (HN) proteins into liposomal vesicles. Virosomes that contained luciferase reporter genes were tested in 293 transformed human kidney cells. F/HN-virosomes that were prepared with an artificial Sendai viral envelope (ASVE-virosomes) or phosphatidylserine (PS-virosomes) exhibited an 8- or 6-fold higher gene-transfer efficiency than cationic liposomes that were made with 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). F/HN-virosomes that were prepared with phosphatidic acid (PA-virosomes) instead of PS were less efficient in gene transfer than either ASVE- or PS-virosomes. In addition, the genetransfer capability of ASVE- and PS-virosomes was maximal at a $Ca^{2+}$ concentration of 510 mM. These results suggest that the incorporated lipid components significantly affect the in vitro gene transfer that is mediated by Sendai F/HN-virosomes.