• Journal of Pharmaceutical Investigation
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• v.22 no.2
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• pp.115-124
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• 1992

The characteristics and stabilities of phosphatidylcholine liposomes covalently coupled with immunoglobulin fragments prepared by the REV method were investigated by the dynamic light scattering, absorbance and calcein release. Using a sulfhydryl-reactive phospholipid derivative of N-[4$({\rho}-maleimido-phenyl)$ butyl] phosphatidylethanolamine (MPB-PE), Fab' antibody fragments were covalently combined with preformed large unilamellar vesicles (LUV), Coupling ratio was $250\;{\mu}g$ of $Fab'/{\mu}mol$ of phospholipid in vesicles, From dynamic light scattering, it was found that the size of the vesicles increases as the ratio of cholesterol to lipid increases, but that apparently, the size of liposomes was not sensitive to the existence of Fab' fragments. Regardless of inserting Fab' fragments, the absorbance of liposomes decreased as the amounts of bile salt (BS) added. At very low BS concentrations, BS/lipid aggregates would be formed in the outer vesicles monolayer, while, at the high BS concentrations, mixed micelles would be preferred. The vesicles incorporated with Fab' fragments, however, are more resistant to the bile salts than the MPB-PE vesicle are. The absorbance of vacant liposomes and calcein release resulted in that the Fab' vesicles and MPB-PE vesicles by the REV method are very stable, but that those by the sonication method sufferred the significant change of turbidities.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.91-101
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• 1997

The biosynthesis of phospholipid and the composition of fatty acid in C. ellipsoidea mitochondria treated with antibiotics(cycloheximide, nalidixic acid) during the culture analyzed. The growth of Chlorella and the contents of total lipid in mitochondria treated with antibiotics were lower than those of the control. The synthesis of PC (phosphatidylcholine) and PI(phosphatidylinostiol) were inhibited in the nalidixic acid treatment and also the contents of PC(phosphatidylcholine), PE (phosphatidylethanolamine), PG(phosphatidylglycerol) and PI(phosphatidylinositol) in the cycloheximide treatment were also inhibited. The major fatty acids utilized for the various phospholipids formation in each antibiotics treatment were analyzed stearic acid, myristic acid, palmitic acid, oleic acid, linoleic acid and linolenic acid at the late phase of the culture.

• KSBB Journal
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• v.10 no.3
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• pp.231-236
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• 1995

For continuous ethanol production In an immobilized cell reactor consisting of Saccharomyces sake, feedings of one tenth to three tenths times diluted fermentation media were effective for maintaining the high ethanol productivity and physical stability of immobilized beads. In case two tenths times dilltued one of the fermentation medium supplemented with egg albumin hydrolysate(0.5%) and phosphatidylcholine(0.5%) was fed, a maximum ethanol productivity of $69 g/\ell$-hr was attained at a dilution rate of$1.1lhr^{-1}$, and it was 50% higher than that of the two tenths times diluted one of the fermentation medium without any supplement, $46 g/\ell$-hr.

• BMB Reports
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• v.29 no.1
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• pp.11-16
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• 1996

The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.

• Korean journal of food and cookery science
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• v.27 no.3
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• pp.51-57
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• 2011

Color, lipid and fatty acid composition, and tocopherols and polyphenols contents of perilla seed lipids in response to seed germination were studied. Perilla seeds were germinated at $30^{\circ}C$ in the dark for 12, 36, or 48 h, after which total lipids were extracted by the Folch method using chloroform and methanol (2:1, v/v). Seed germination resulted in a decrease in yellowness and greenness in perilla seed lipids, but there were no significant changes in composition of the lipids including major neutral lipids (>90%). Contents of phosphatidylcholine and phosphatidylethanolamine in the perilla seed lipids significantly increased in response to germination. Linolenic acid (>63%) was the most abundant fatty acid. Seed germination tended to decrease the relative content of linolenic acid and increase the contents of oleic and stearic acids. Contents of antioxidants, especially ${\alpha}$-tocopherol and polyphenols, increased in response to seed germination. As the germination period was extended, the antioxidant content increased. Therefore, increases in useful components, phosphatidylcholine, phosphatidylethanolamine, ${\alpha}$-tocopherol, and polyphenols contents by seed germination can contribute to the improvement of perilla seed utilization in food industry.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.211-216
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• 2004

A bacterial strain JE-ll found to produce active extracellular phospholipase D (PLD) was selected from the soil isolates. It was identified as Streptomyces somaliensis on the basis of 16S rDNA sequence analysis, morphological and physiological characteristics. The gene (sspld) encoding S. somaliensis PLD was isolated and characterized. The open reading frame was suggested to encode 538 amino acids with a signal peptide of 33 amino acids. The deduced amino acid sequence of the sspld shared a sequence similarity of 70-88％ with PLDs of other Streptomyces sp. so far reported. The PLD converted phosphatidylcholine to phosphatidylglycerol or phosphatidylserine with the yield of 96 to 99％ (㏖/㏖), but did not act on inositol or ethanolamine as a transphosphatidylation donor.

• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.448-452
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• 2000

Phospholipase D(PLD) is the enzyme catalyzing the hydrolysis of the terminal phosphcester bond of phospholipid head group to produce phosphatidic acid and the corresponding base. The effect of spermine on the PLD activity of rat brain mitochondrial preparation was investigated. Spermine, in the presence of oleic acid, activates the rat brain mitochondrial PLD, whose effect was further enhanced by the presence of divalent cation, $Ca^{2+}$, $Mg^{2+}$, and $Ba^{2+}$. Among the various monoamines tested, only histamine at the high concentration was effective in activation the PLD. Polylysine increased the PLD activity, particularly, the longer chain of the molecule activated the PLD more effectively. There was no significant difference in the substrate specificity for the PLD activity between phosphatidylcholine(PC) and phoshpatidylethanolamine (PE). This substrate specifitiy is different from the PE specificity reported for the intestinal mitochondrial PLD.

• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.51-55
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• 2007

Solid lipid nanoparticles (SLNs) have been regarded to behave similar to the vegetable oil emulsions because emulsions of lipid melts are formed before lipid droplets being solidified to turn into SLNs. Compared to lipid emulsion, however, it has been more difficult to obtain stable SLNs and needs more extensive considerations on stabilizer and manufacturing process. In the present study, we tried to prepare phosphatidylcholine-based trymyristin (TM) SLNs using high pressure homogenization method and optimize the manufacturing variables such as homogenization pressure, number of homogenization cycles, cooling temperature, co-stabilizer and freeze-drying with cryoprotectants. Nano-sized TM particles could be Prepared using egg Phosphatidylcholine and pegylated phospholipids ($PEG_{2000}$PE) as stabilizers. Based on the optimization study, the dispersion was manufactured by homogenization under the pressure of 100 MPa for more than 5 cycles, and solidifying the intermediately formed lipid melt droplets by dipping in liquid nitrogen followed by thawing at room temperature. In addition, TM SLNs could be freeze-dried and then redispersed easily without significant particle size changes after freeze drying with 10% and 12.5% sucrose or trehalose. The TM SLNs established in this study can be used as delivery system for drugs and cosmetics.

• Journal of Dairy Science and Biotechnology
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• v.14 no.2
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• pp.195-206
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• 1996

Cholesterol assimilated by Lactobacillus acidophilus ATCC 43121 was not metabolically degraded in that most of it was recovered with the cells. Cells grown in the presence of cholesterol micelles and bile salts were more resistant to Iysis by sonication than those grown in their absence, suggesting a possible alteration of cellular membranes. Cholesterol assimilation occurred during growth at pH 6.0, the amount of which was more than that by cells grown without pH control. Cholesterol assimilated by cells was recovered in the membrane fractions of cells both grown at pH 6.0 and without pH control. The effect of unsaturated fatty acids on cholesterol assimilation was not clear, since there was no significant (P> 0.05) difference in the amount taken up from micelles prepared using L-${\alpha}$-phosphatidylcholine, dioleoyl or L-${\alpha}$-phosphatidylcholine, distearoyl. Without Tween 80, little, if any, cell growth or cholesterol uptake was observed. In the presence of 0.05% Tween 80, cholesterol uptake increased dramatically as did growth. However, as the amount of Tween 80 increased beyond 0.05%, cholesterol uptake decreased while the amount of growth remained the same.

• Bulletin of the Korean Chemical Society
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• v.18 no.7
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• pp.761-766
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• 1997

Phospholipase C from Clostridium perfringens is known to catalyze the hydrolysis of phospholipids in biological membranes. In this study, a simple and sensitive method for assaying phospholipase C was developed by using liposomes entrapping calcein as a fluorescent marker. Phospholipase C-induced lysis of liposomes was determined by measuring the fluorescence intensity of calcein released out from liposomes, Various liposomes with different compositions were prepared by reverse-phase evaporation method to investigate the effect of liposomal composition on the lytic activity of phospholipase C. The calcein-entrapping efficiency of liposomes was affected by the chain length of fatty acid in phosphatidylcholine constituting liposomes. The lytic activity of phospholipase C was the highest against liposomes prepared with eggPC. The lytic activity decreased with increasing chain length of fatty acid in phosphatidylcholine. Incorporation of cholesterol more than 20% into the liposomal bilayer inhibited the phospholipase C-induced lysis. The lysis of liposomes was more greatly increased by the addition of 10 mM of calcium. The lytic activity of phospholipase C was also affected by the surface charge of liposomes. Taken together, it was concluded that reverse-phase evaporation vesicles composed of dipalmitoylphosphatidylcholine and cholesterol in the molar ratio of 9 : 1 allowed to detect the lowest concentration of phospholipase C (0.10 μg/assay volume). This study suggested that the use of liposomes can provide a simple, sensitive and inexpensive method for assaying phospholipase C.