• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.20-26
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• 2003

A bacterial strain was isolated from seawater to screen for phytase activities. A colony had the highest activity and was identified as an Escherichia coli strain. Using primers derived from E. coli acid phosphatase appA sequence, we cloned a 1,495 bp DNA fragment connected with the pGEM-T vector. It was over-expressed under lac promoter combined with its native promoter in E. coli $DH5\alpha$. The expression of the phytase gene occurred during late exponential growth and the intracellular phytase production was 16.9 units/ml. The yield of recombinant phytate was 412-fold higher than that of wild type E. coli K13.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.635-648
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• 1998

The clinical use of fluoride with a well known osteogenic action in osteoporotic patients is rational, because this condition is characterized by impaired bone formation. However, its anabolic effect has not been demonstrated well in vitro. The purpose of this study was to investigate the effects of sodium fluoride on the physiological role of osteoblastic cell. Osteoblastic cells were isolated from fetal rat calvaria. The results were as follows : 1. Mineralized nodules were shown in osteoblastic cell cultures, which had been maintained in the presence of ascorbic acid and ${\beta}-glycerophosphate$ up to 21 days. When cultures were treated with pulses of 48 hr duration before apparent mineralization was occurring, 2-fold increased in their number was detected. 2. Alkaline phosphatase activity of osteoblastic cells was inhibited by sodium fluoride in dose dependent manner. 3. The effect of sodium fluoride on the osteoblastic cell proliferation was measured by the incorporation of $[^3H]$-thymidine into DNA. As a result, sodium fluoride at $1{\sim}100{\mu}M$ increased the $[^3H]$-thymidine incorporation into DNA in a dose dependent manner. 4. The signaling mechanism activated by sodium fluoride dose-dependently enhanced the tyrosine phosphorylation of the adaptor molecule $Shc^{p66}$ and their association with Grb2, one of earlier events in a MAP kinase activation pathway cascade used by a significant subset of G protein-coupled receptors. 5. The phosphorylation of CREB(cAMP response element binding protein)was inhibited by the sodium fluoride in MC3T3E1 cells. In conclusion, the results of this study suggested that the mitogenic effect of the sodium fluoride in MC3T3E1 cell was stimulated in a dose-dependent manner and suggested "an important role for the interaction between She and Grb2" in controlling the proliferation of osteoblasts.

• Journal of fish pathology
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• v.20 no.1
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• pp.49-60
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• 2007

Non-hemolytic Streptococcus parauberis isolated from diseased olive flounder, Paralichthys olivaceus in the South coast of Korea were identified by physiological, biochemical and genetic analysis in order to define the different characteristics geographically. First, twelve strains of S. parauberis were isolated from catalase-negative gram-positive cocci by multiplex PCR assay. Phenotypic identifications were performed with commercially available kit (API 20 Strep and API ZYM system). Analysis of API profiles of the isolates showed that strains were identified as either of Lactococcus lactis, S. constellatus or S. uberis. Moreover, S. parauberis isolated from olive flounder differed from that of turbot (X89967) to the test of not Voges-Proskauer, arginine, hippurate, alkiline phosphatase and pyrroidonyl arylamidase but β-glucuronidase. All S. parauberis isolates were sensitive to florfenicol, ampicillin, ofloxacin and vancomycin but were resistant to oxolinic acid, flumequine, nalidixic acid and sulfisoxazol. However, the 16S rDNA sequences of the isolates showed 99% similarity to S. parauberis KCTC 3651 (AY584477) and a great homogenecity among the flounder isolates.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.159-172
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• 1991

It has been investigated what could be the selective marker distinguishing the immature from mature spermatozoa and whether fi -glucuronidase and fi -glucosidase are dependent on androgen in the luminal fluid of the epididymis or not. The contents of hexose, hexosamine and sialic acid in the epithelial cells, luminal fluid and spermatozoa of the epididymis were examined and the patterns of protein bands were compared in each group of the luminal fluid by SDS-PAGE. Lactate dehydrogenase, glucose-6-phosphatase, Na+ -K+ -ATPase and MgNa-ATPase showed higher activities in the cauda than the caput epididymal spermatozoa but only $Mg^2$+-ATPase activity appeared to be changed significantly. When the contents of hexose, hexosamine and sialic acid were analyzed and compared quantitatively, those of hexose were significantly different in the luminal fluid of caput and cauda epididymis, those of hexosamine in the epithelial cells and those of sialic acid in the epithelial cells and luminal fluid. When SDS-PAGE has been performed in each group, the band of MW 33-37 KD which was absent in the luminal fluid of caput epididymis appeared obviously in the luminal fluid of cauda epididymis and ako apeared in the cauda sperm crude membrane fraction. In addition, $\beta$ -glucuronidase and $\beta$ -glucosidase activities and their dependence on androgen were measured and the SDS-PAGE patiems of proteins and/or glycoproteins in the luminal fluid were examined. The activities of these two enzymes in the luminal fluid of the epididymis decreased significantly from the 5th day after castration. When testosterone was injected, the activity of $\beta$ -glucuronidase began to increase significantly from the 5th day following injection and that of $\beta$ -glucosidase from the loth day. On the other hand, the band of about MW 21 KD was newly observed in the lumen of caput epididymis when testosterone was administered.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1221-1226
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• 2008

The soft rot bacterium Pectobacterium wasabiae is an economically important pathogen of many crops. A new phytase gene, appA, was cloned from P. wasabiae by degenerate PCR and TAIL-PCR. The open reading frame of appA consisted of 1,302 bp encoding 433 amino acid residues, including 27 residues of a putative signal peptide. The mature protein had a molecular mass of 45 kDa and a theoretical pI of 5.5. The amino acid sequence contained the conserved active site residues RHGXRXP and HDTN of typical histidine acid phosphatases, and showed the highest identity of 48.5% to PhyM from Pseudomonas syringae. The gene fragment encoding the mature phytase was expressed in Escherichia coli BL21 (DE3), and the purified recombinant phytase had a specific activity of 1,072$\pm$47 U/mg for phytate substrate. The optimum pH and temperature for the purified phytase were pH 5.0 and 50$^{\circ}C$, respectively. The $K_m$ value was 0.17 mM, with a $V_{max}$ of 1,714 $\mu$mol/min/mg. This is the first report of the identification and isolation of phytase from Pectobacterium.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.280-285
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• 2012

The developing embryo naturally experiences relatively low oxygen conditions in vivo. Under in vitro hypoxia, mouse embryonic stem cells (mESCs) lose their self-renewal activity and display an early differentiated morphology mediated by the hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$). Previously, we demonstrated that histone deacetylase (HDAC) is activated by hypoxia and increases the protein stability and transcriptional activity of HIF-$1{\alpha}$ in many human cancer cells. Furthermore HDAC1 and 3 mediate the differentiation of mECSs and hematopoietic stem cells. However, the role of HDACs and their inhibitors in hypoxia-induced early differentiation of mESCs remains largely unknown. Here, we examined the effects of several histone deacetylase inhibitors (HDACIs) on the self-renewal properties of mESCs under hypoxia. Inhibition of HDAC under hypoxia effectively decreased the HIF-$1{\alpha}$ protein levels and substantially improved the expression of the LIF-specific receptor (LIFR) and phosphorylated-STAT3 in mESCs. In particular, valproic acid (VPA), a pan HDACI, showed dramatic changes in HIF-$1{\alpha}$ protein levels and LIFR protein expression levels compared to other HDACIs, including sodium butyrate (SB), trichostatin A (TSA), and apicidin (AP). Importantly, our RT-PCR data and alkaline phosphatase assays indicate that VPA helps to maintain the self-renewal activity of mESCs under hypoxia. Taken together, these results suggest that VPA may block the early differentiation of mESCs under hypoxia via the destabilization of HIF-$1{\alpha}$.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.15-21
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• 2004

The immunomodulating activities and chemical characteristics of a water-soluble exopolymer from submerged mycelial culture of Phellinus pini were studied. Anticomplementary activity of this polymer was found to be $73.2\%$, and its activation system occurred through both classical and alternative pathways, where the classical pathway was detected to be the major one by crossed immunoelectrophoresis. Nitric oxide (NO) release ability and acid phosphatase activity of macrophage were increased by 1.6-fold ($100{\mu}g/ml$) and 3.4-fold ($500{\mu}g/ml$), respectively, and splenocyte proliferation in mixed lymphocyte reaction (MLR) was also increased by 2.6-fold ($200{\mu}g/ml$), compared to the control. The molecular weight of this polymer, determined by HPLC, was under 5 kDa. Total sugar and protein contents were 89.7 and 10.3%, respectively. Both sugar and amino acid compositions of the exopolymer were also analyzed.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.144-152
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• 1998

Changes of biological components in haemolymph of Helicoverpa assulta Guenee were investigated during the development and pupae of cold-stress periods. Protein content was the highest in the larval stage, whereas it showed somewhat lower level at the cold-stressed pupae. The level of free amino acids was high in the larval and adult stages. Althougth decresed in pupal stage, the level of free amino acid remarkably increased at the cold-stressed pupae. Total lipids were a little increased at the pupal stage, after small quantity decreased in I-day old adults, and then remarkably decreased at the cold-stressed pupae. Glycogen was increased at the pupal stage, and somewhat decreased in the stage of adult, but remarkably decreased at the cold-stressed pupae. From thin layer chromatographic analysis, glucose was detected in small quantity at 1-day old pupae, one-day old adults, and cold-stressed pupae, respectively. Each .activity of acid and alkaline phosphatases was the highest in the 1 and 7-day old pupae, respectively, and both enzyme activities were increased about two-fold compared to the activity in the cold-stressed pupae. A total of 2 phosphatase isozymes were observed in throughout the developmental stage, and a new isozyme specific to cold-stressed pupae was identified.

• Journal of Nutrition and Health
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• v.32 no.5
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• pp.519-525
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• 1999

The effects of Ganoderma Lucidum consumption (GL) on the liver function and lipid metabolic disorder induced by alcohol consuming were studied in rats using GL powder(1%, 2%, 4%) and 10% ethly alcohol. Thirty-five rats(Sprague-Dawley, male) were divided into five groups and fed experimental diets for seven weeks. The concentrations of serum cholesterol, HDL-cholesterol and triglyceride were the highest in the alcohol group, while the levels were apparently reduced by in groups fed GL. The atherogenic indices(AI) also tended to be higher in the alcohol group. Glutamic oxaloacetic transaminase(GOT) activities were significantly lower in body alcohol + 2% GL and alcohol + 4% GL groups, and glutamic pyruvic transaminase(GPT)activities lower only in the alcohol + 2% GL compared with the alcohol group. Alkaline phosphatase(ALP) activities were not significantly different among the groups. The elevated levels of liver cholesterol and triglyceride due to alcohol consumption, were apparently reduced by GL supplementation. On microscopic observation of liver tissues, fat droplets appeared extensively on the liver-lobule in the alcohol group, while fat droplets appeared only on the central vein in the alcohol + 1% GL group. However, in groups administered 2% and 4% GL, fat droplets appeared similar to the alcohol group. The concentrations of fecal bile acid were significantly increased in groups fed GL. These results indicate that GL exerted some beneficial effects on lipid metabolic disorder caused by long-term alcohol consumption. Thus, it seems that GL may be effective in preventing or curing some aspects of alcohol toxicity. More detailed studies are needed in order to determine proper dietary levels of GL for combating alcohol toxicity.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.342-346
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• 2008

Aurintricarboxylic acid (ATA) prevents apoptosis in a wide range of cell types, including PC12 cells. ATA is known to increase the phosphorylation level of IGF-1 receptor (IGF-1R) and downstream signaling proteins. ATA can translocate across the plasma membrane of PC12 cells and inhibit protein tyrosine phosphatases (PTPs) and, therefore, it is not clear whether ATA exerted its antiapoptotic effect through activation of IGF-1R or by inhibition of cytosolic PTPs. When PC12 cells, deprived of serum, were treated with Fab fragment of anti-IGF-1R antibody to prevent the binding of ATA to the extracellular domain of IGF-1R, ATA was found to penetrate into the cytosolic space of the cells. Under these conditions, the survival-promoting effects of ATA were abolished, and the increase of phosphorylation and characteristic cleavage of IGF-1R were not observed. These results indicate that the antiapoptotic effect of ATA in PC12 cells is due to the binding of ATA to the extracellular domain of IGF-1R and subsequent activation of the IGF-1R, not inhibition of cytosolic PTP(s).