• Journal of Life Science
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• v.24 no.12
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• pp.1378-1382
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• 2014

Phospholipase D (PLD) catalyzes the hydrolysis of phospholipid to phosphatidic acid (PA), a lipid secondary messenger. Two forms of PLD isozymes, phosphatidylcholine-specific PLD1 and PLD2, have been identified. PLD has emerged as a critical regulator of cell proliferation and survival signaling, and dysregulation of PLD occurs in a various illnesses, including cancer. PLD activity is essential for cell survival and protection from apoptosis. Overexpression of PLD isozymes or PLD-generated PA attenuates the expression of apoptotic genes and confers resistance to apoptosis. The apoptosis-related molecular mechanisms of PLD remain largely unknown. Recently, the dynamics of PLD turnover during apoptosis have been reported. The cleavage of PLD isozymes as specific substrates of caspase differentially regulates apoptosis. PLD1 is cleaved at one internal site, and PLD2 is cleaved two sites at the front of the N-terminus. The cleavage of PLD1 reduces its enzymatic activity, probably via the dissociation of two catalytic motifs, whereas the cleavage of PLD2 does not affect the catalytic motifs and its activity. Thus, PLD2 maintains antiapoptotic capacity, despite its cleavage. Therefore, the differential cleavage pattern of PLD isozymes by caspase affects its enzymatic activity and antiapoptotic function. Thus, PLD is considered a potential target for cancer therapy. We summarize recent studies regarding the functional role of PLD in apoptosis.

• Journal of Acupuncture Research
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• v.17 no.4
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• pp.69-78
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• 2000

Objective : To research the trends of the study related to bee venom and cancer, and to establish the hereafter direction of the study on bee venom herbal acupuncture. Method : We searched in PubMed, with bee venom and cancer(in English, with abstract) Results : 1. We searched 28 Journals, 36 Papers. the frequency of Journals and Papers was as follows: Biochem Biophys Res Commun(4 Papers), FEBS Lett(3), Life Sci, Proc Natl Acad Sci USA, J Immunol(each 2), other 23 Journals(each 1). 2. The pattern of the study was as follows: Review article(3 Journals, 3 Papers), Epidemiologic study(1, 1), Experimental study(24, 32) In vivo 1, 1), In vitto(24, 31) 3. The involved components of bee venom were as follows: Melittin(20), Apamin(8), Phospholipase A2(3), Melittin & Phospholipase A2(3), Melittin& Tertiapin(1). 4. The involved cancer was as follows: leukemia(9), tumor(5), neuroblastoma(4), pituitary tumor and pheochromocytoma(each 3), lymphoma, astrocytoma, glioma and lung cancer(small cell carcinoma)(eacn 2), bladder carcinoma, pancreatic cancer, breast carcinoma, ovarian carcinoma and spuamous cell carcinoma(each 1) Conclusion : We concluded that the most frequent pattern of the study was in vitro experimental study with peptide components of bee venom and the most frequeni invovled cancer was leukemia.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.189-195
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• 2002

Using Streptomyces sp. YU100 isolated from Korean soil, the fermentative production of phospholipase D was attempted along with its purification and characterization studies. When different carbon and nitrogen sources were supplemented in the culture medium, glucose and yeast extract were found to be the best. By varying the concentration of nutrients and calcium carbonate, the optimal culture medium was determined as 2.0% glucose, 1.5% yeast extract, 0.5% tryptone 0.3% calcium carbonate. During cultivation, the strain secreted most of the phospholipase D in the early stage of growth within 24 h. The phospholipase D produced in the culture broth exhibited hydrolytic activity as well as transphosphatidylation activity on lecithin (phosphatidylcholine). In particular, the culture broth showed 8.7 units/ml of hydrolytic activity when cultivated at $28^{\circ}C$ for 1.5 days. The phospholipase D was purified using 80% ammonium sulfate precipitation and DEAE-Sepharose CL-6B column chromatography, which produced a major band of 57 kDa on a 10% SDS-polyacrylamide gel with purity higher than 80%. The enzyme showed an optimal pH of 7 in hydrolytic reaction, and at pH 4 in a transphosphatidylation reaction. The enzyme activity increased until the reaction temperature was elevated to $60^{\circ}C$. The enzyme was relatively stable at high temperatures and neutral pH, but significantly unstable in the alkaline range. Among the detergents tested as emulsifiers of phospholipids, the highest enzyme activity was observed when 1.5% Triton X-100 was employed. However, no inhibitory effect by metal ions was detected. Under optimized reaction conditions, the purified enzyme not only completely decomposed PC to phosphatidic acid within 1 h, but also exhibited higher than 80% conversion rate of PC to PS by transphosphatidylation within 4 h.

• Childhood Kidney Diseases
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• v.24 no.1
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• pp.36-41
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• 2020

Purpose: Hepatitis B virus (HBV) infection is among etiologies of secondary membranous nephropathy (MN) in pediatric patients. We evaluated expression of phospholipase A2 receptor (PLA2R), a specific target antigen of primary MN, in pediatric HBV-related MN. Methods: We retrospectively reviewed patients with biopsy-proven HBV-related MN from the renal biopsy registry and electronic medical records of Severance Hospital, Seoul, Korea, from 1993 to 2004. Paraffin-embedded human kidney tissues were retrieved and immunohistochemically stained for PLA2R. Results: Ten pediatric patients with 13 biopsied specimens were reviewed. The predominant pathological stage was stage II-III, and second was stage II. The intensity of staining for IgG was greatest, with less intense staining for IgM, IgA, C3, C4, and C1q. All the patients had angiotensin-converting enzyme inhibitor combined with glucocorticoid, and four patients converted to cyclosporine treatment from glucocorticoid monotherapy. Urinalysis of all the patients normalized after variable period. PLA2R staining was demonstrated in the outer glomerulus in 3 out of 13 biopsies, 2 of which were obtained from the same patient over a 5-year interval. Conclusions: PLA2R was expressed in a small number of cases diagnosed as pediatric HBV-related MN, indicating that some HBV-related MN cases may be primary MN concurrent with HBV infection.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.19-26
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• 1996

A phospholipase C (PLC) inhibitor (MT267-2B) was isolated from the culture broth of actinomycetes isolate MT2617-2 by the extraction with n-butanol and column chromatographic techniques. The molecular weight of the inhibitor was 1057, by the spectroscopic analyses of IR, $^{13}C$-and $^{1}H$-NMR and ESI-MS. The chemical structure of MT2617-2B was found to be a macrolide compound consisted of a hemiketal ring, polyhydroxyl and polymethyl groups, which had a malonate and guanidine group as its side chain. MT2617-2B produced its two isomers having the same molecular weight by standing in methanol solution at room temperature. Therefore, MT2617-2B was identified as copiamycin and niphithricin A, macrolide antibiotics. The values of $IC_{50}$ against PLC-${\gamma}$1 and PLC-${\beta}$1 were 25 and 50${\mu}$g/ml, respectively. MT2617-2B had antimicrobial activities against Staphylococcus aureus and Candida albicans, but not against Escherichia coli.

• Korean Journal of Microbiology
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• v.24 no.1
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• pp.38-45
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• 1986

Effect of sodium deoxycholate and sodium dodecyl sulfate on Rhizopus oryzae were investigated. Morphological change was obtained by supplement of these surfactants into culture media during the sumerged culture. In accordance with morphological changes, composition of phospholipid was changed. In case of surfactant-free culture, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine were measured more than 95% of total phospholipid. But cardiolipin and phosphatidylinositol were conspicuously increased by treatment of both sufactants. Presence of phospolipase A, C, and D were detected from mycelium. Phospholipase A and D were activated by supplement of sodium deoxycholate and C was activated by sodium dodecyl sulfate. These results were interpreted in respect of polymorphism of phospholipid and membrane stability against solubilization effect of surfactants.

• Journal of Pharmacopuncture
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• v.5 no.2
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• pp.40-51
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• 2002

Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide-induced expression phospholipase $A_2$, cyclooxygenase-2 and inducible nitrogen oxide synthase, and the generation of arachidonic acid, prostaglandin D2 and E2 in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase $A_2$, cyclooxygenase and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was assayed by ELISA method in RAW 264.7 cells. The non-toxic concentrations (0.1 to $5\;{\mu}g/ml$) of bee venom determined by MTT assay, were used in this study. Results : 1. Bee venom inhibited lipopolysaccharide-induced expression of phospholipase $A_2$ in a dose dependent manner after 48 hours treatment. 2. Bee venom inhibited lipopolysaccharide-induced expression of cyclooxygenase-2 in a dose dependent manner after 24 and 48 hours treatment. 3. Bee venom inhibited lipopolysaccharide-induced expression of inducible nitrogen oxidesynthase in a dose dependent manner after 48 hours treatment. 4. The generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was not much affected by the treatment of bee venom on the lipopolysaccharide-induced generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ in RAW 264.7 cells.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.237-242
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• 1996

Two depsides, medicinal herb products isolated from the methanol extract of Umbilicaria esculenta, inhibited human synovial fluid Phospholipase $A_2\;(PLA_2)$ ($IC_{50}$ of 0.22 and 0.26 mM, respectively). In the course of screening for antiinflammatory compounds from natural products, we successfully isolated two depsides $PLA_2$ inhibitory compounds, Orcinol and methyl orsellinic acid. The compounds were identified as orcinol and methyl orsellinic acid on the basis of various NMR studies including $^1H,\;^{13}C$ and DEPT experiments.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.2046-2056
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• 2018

Phospholipase D has great commercial value due to its transphosphatidylation products that can be used in the food and medicine industries. In order to construct a strain for use in the production of PLD, we employed a series of combinatorial strategies to increase PLD expression in Bacillus subtilis WB600. These strategies included screening of signal peptides, selection of different plasmids, and optimization of the sequences of the ribosome-binding site (RBS) and the spacer region. We found that using the signal peptide amyE results in the highest extracellular PLD activity (11.3 U/ml) and in a PLD expression level 5.27-fold higher than when the endogenous signal peptide is used. Furthermore, the strain harboring the recombinant expression plasmid pMA0911-PLD-amyE-his produced PLD with activity enhanced by 69.03% (19.1 U/ml). We then used the online tool \RBS Calculator v2.0 to optimize the sequences of the RBS and the spacer. Using the optimized sequences resulted in an increase in the enzyme activity by about 26.7% (24.2 U/ml). In addition, we found through a transfer experiment that the retention rate of the recombinant plasmid after 5 generations was still 100%. The final product, phosphatidylserine (PS), was successfully detected, with transphosphatidylation selectivity at 74.6%. This is similar to the values for the original producer.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.1
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• pp.31-36
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• 2012

The receptor activator of NF-${\kappa}B$ ligand (RANKL) signal is an activator of tumor necrosis factor receptor-associated factor 6 (TRAF6), which leads to the activation of NF-${\kappa}B$ and other signal transduction pathways essential for osteoclastogenesis, such as $Ca^{2+}$ signaling. However, the intracellular levels of inositol 1,4,5-trisphosphate ($IP_3$) and $IP_3$-mediated cellular function of RANKL during osteoclastogenesis are not known. In the present study, we determined the levels of $IP_3$ and evaluated $IP_3$-mediated osteoclast differentiation and osteoclast activity by RANKL treatment of mouse leukemic macrophage cells (RAW 264.7) and mouse bone marrow-derived monocyte/macrophage precursor cells (BMMs). During osteoclastogenesis, the expression levels of $Ca^{2+}$ signaling proteins such as $IP_3$ receptors ($IP_3Rs$), plasma membrane $Ca^{2+}$ ATPase, and sarco/endoplasmic reticulum $Ca^{2+}$ ATPase type2 did not change by RANKL treatment for up to 6 days in both cell types. At 24 h after RANKL treatment, a higher steady-state level of $IP_3$ was observed in RAW264.7 cells transfected with green fluorescent protein (GFP)-tagged pleckstrin homology (PH) domains of phospholipase C (PLC) ${\delta}$, a probe specifically detecting intracellular $IP_3$ levels. In BMMs, the inhibition of PLC with U73122 [a specific inhibitor of phospholipase C (PLC)[ and of $IP_3Rs$ with 2-aminoethoxydiphenyl borate (2APB; a non-specific inhibitor of $IP_3Rs$) inhibited the generation of RANKL-induced multinucleated cells and decreased the bone-resorption rate in dentin slice, respectively. These results suggest that intracellular $IP_3$ levels and the $IP_3$-mediated signaling pathway play an important role in RANKL-induced osteoclastogenesis.