• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.679-685
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• 2011

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

• YAKHAK HOEJI
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• v.46 no.3
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• pp.192-196
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• 2002

To investigate the effect of intravenous ethanol administration on pancreatic exocrine secretion, we measured volume and protein amount in pancreatic juice and assayed amylase activity and phospholipase $A_2$ activity in pancreatic fragments and serum. Acute pancreatitis induced by obstruction of common bile-pancreatic duct (CBPD) and caerulein infusion (5 $\mu\textrm{g}$/kg/hr) showed typical characteristics, such as hyperamylasemia and pancreatic edema and increase of phospholipase $A_2$ activity in pancreatic fragments and serum. Intravenous ethanol infusion (50 mg/kg/hr) significantly stimulated pancreatic exocrine secretion, but such a stimulatory effect of ethanol disappeared at dose of 100 mg/kg/hr without typical symptoms of acute pancreatitis. In microscopic examination, there were no typical changes of edematous pancreatitis in ethanol administrated rats. These results suggest that acute ethanol administration has dual effect on exocrine pancreatic secretion: low dose of ethanol (50 mg/kg/hr) stimulates pancreatic exocrine secretion, whereas high dose of ethanol (100 mg/kg/hr) does not without typical changes of edematous pancreatitis.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.3
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• pp.293-300
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• 2017

Prostaglandin $D_2$ ($PGD_2$) may act against myocardial ischemia-reperfusion (I/R) injury and play an anti-inflammatory role in the heart. Although the effect of $PGD_2$ in regulation of ANP secretion of the atrium was reported, the mechanisms involved are not clearly identified. The aim of the present study was to investigate whether $PGD_2$ can regulate ANP secretion in the isolated perfused beating rat atrium, and its underlying mechanisms. $PGD_2$ (0.1 to $10{\mu}M$) significantly increased atrial ANP secretion concomitantly with positive inotropy in a dose-dependent manner. Effects of $PGD_2$ on atrial ANP secretion and mechanical dynamics were abolished by AH-6809 ($1.0{\mu}M$) and AL-8810 ($1.0{\mu}M$), $PGD_2$ and prostaglandin $F2{\alpha}$ ($PGF2{\alpha}$) receptor antagonists, respectively. Moreover, $PGD_2$ clearly upregulated atrial peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and the $PGD_2$ metabolite 15-deoxy-${\Delta}12$, 14-$PGJ_2$ (15d-$PGJ_2$, $0.1{\mu}M$) dramatically increased atrial ANP secretion. Increased ANP secretions induced by $PGD_2$ and 15d-$PGJ_2$ were completely blocked by the $PPAR{\gamma}$ antagonist GW9662 ($0.1{\mu}M$). PD98059 ($10.0{\mu}M$) and LY294002 ($1.0{\mu}M$), antagonists of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling, respectively, significantly attenuated the increase of atrial ANP secretion by $PGD_2$. These results indicated that $PGD_2$ stimulated atrial ANP secretion and promoted positive inotropy by activating $PPAR{\gamma}$ in beating rat atria. MAPK/ERK and PI3K/Akt signaling pathways were each partially involved in regulating $PGD_2$-induced atrial ANP secretion.

• Korean Journal of Veterinary Research
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• v.46 no.2
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• pp.97-105
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• 2006

All-trans retinoic acid (AtRA) induces growth inhibition and apoptosis in a variety of tumer cells, including MCF-7 cells. Insulin-like growth factors (IGFs) system has been reported to be associated with the development of cancer. Although MCF-7 cell with AtRA is to be the major stimulus for the cell growth and apoptosis, the mechanism of insulin-like growth factor-I (IGF-I)/insulin-like growth factor binding protein-3 (IGFBP-3) system remains to be elucidated. Thus, this study was conducted to the effect of AtRA on the gene expression and level of IGF-I and IGFBP-3. In addition, we investigated the involvement of PKC-${\delta}$ on the IGF-I and IGFBP-3 secretion in MCF-7 cell. AtRA(${\geq}10^{-7}M$) decreased the IGF-1 secretion and mRNA expressions, but increased IGFBP-3 secretion and mRNA expressions in MCF-7 cells. Especially, the treatment of AtRA at 72 hours caused a significant reduction in the IGF-I secretion and mRNA expressions but increment in IGFBP-3 secretion and mRNA expressions (p < 0.05). $10^{-7}M$ AtRA activated PKC-${\delta}$ that is one among PKC-$\iota$, ${\alpha}$, ${\lambda}$ and ${\delta}$ in MCF-7 cell. Rotllerin, a PKC-${\delta}$ inhibitor, blocked AtRA-induced inhibition of the IGF-I and mRNA expressions, and increase of lGFBP-3 and mRNA expressions in MCF-7 cell. Together, AtRA inhibited the IGF-I secretion and mRNA expressions, but increased IGFBP-3 secretion and mRNA expressions in MCF-7 cell. Furthermore, AtRA-induced alteration of IGF-I, IGFBP-3 secretion, and the gene expressions were mediated via PKC-${\delta}$ activity.

• Journal of Marine Bioscience and Biotechnology
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• v.16 no.1
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• pp.45-54
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• 2024

Microalgae have great potential in the biomedical and pharmaceutical industries as a new type of bioreactor that can produce proteins for specific purposes, including recombinant proteins, pharmaceuticals, and industrial enzymes. Despite the production advantages and importance of microalgae-based expression systems, studies on secretion efficiency are limited. In this study, for stable expression and efficient secretion of the heterologous protein (human SCF and human INFγ) in Chlorella vulgaris, we constructed SP:hSCF:His and SP:hINFγ:His plant binary vectors using the signal peptide (SP) of Chlamydomonas reinhardtii, and we obtained stable transformants through the effective agrobacterium-mediated transformation of these vectors. Transformants with accurately inserted hSCF and hINFγ demonstrated stably increased mRNA and protein expression using RT-PCR and western blotting under the same culture conditions. Following the analysis of the proteins secreted into the culture medium using ELISA, it was confirmed that hINFγ was effectively produced in the transformed C. vulgaris culture medium. The overall findings indicate that the combination of heterologous protein and SP may be crucial for ensuring the expression and secretion of recombinant proteins in Chlorella culture systems.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.2
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• pp.236-243
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• 2000

A number of developments have occurred over recent years that are being used commercially or have the potential to increase the milk yield and consequently the efficiency of dairy cows. Bovine growth hormone is the most widely known of several attempts that have been made to alter the metabolic endocrinology of dairy cows to increase the rate of milk secretion. The factors affecting the milk yield response to growth hormone, growth hormone-releasing factor, thyroxine and placental lactogen as well as to the immuno-neutralization of somatostatin are briefly considered. Secondly, the recent greater understanding of the mechanism by which the milk yield is increased following more frequent milking, which has resulted from the identification and characterization of the feedback inhibitor of lactation (FIL) protein, is reviewed. The identification of this protein provides new avenues of research which may lead to a reduction in the rate of decline in milk yield with advancing lactation or to undiminished milk yields despite a reduction in frequency with which the animals are milked.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.308-314
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• 2005

Both high glucose and glucose degradation products (GDP) have been implicated in alterations of peritoneal membrane structure and function during long-term peritoneal dialysis (PD). The present study examined the role of GDP including methylglyoxal (MGO), acetaldehyde, and 3,4-dideoxyglucosone (3,4-DGE) in HPMC activation with respect to membrane hyperpermeability or fibrosis. The role of reactive oxygen species (ROS) and activation of protein kinase C (PKC) in GDP-induced HPMC activation were also examined. Using M199 culture medium as control, growth arrested and synchronized HPMC were continuously stimulated by MGO, acetaldehyde, and 3,4-DGE for 48 hours. Vascular endothelial growth factor (VEGF) was quantified as a marker of peritoneal membrane hyperpermeability and fibronectin and heat shock protein 47 (hsp47) as markers of fibrosis. Involvement of ROS and PKC was examined by the inhibitory effect of N-acetylcystein (NAC) or calphostin C, respectively. MGO significantly increased VEGF (1.9-fold), fibronectin (1.5-fold), and hsp47 (1.3-fold) secretion compared with control M199. NAC and calphostin C effectively inhibited MGO-induced VEGF upregulation. Acetaldehyde stimulated and 3,4-DGE inhibited VEGF secretion. Fibronectin secretion and hsp47 expression in HPMC were not affected by acetaldehyde or 3,4-DGE In conclusion, MGO upregulated VEGF and fibronectin secretion and hsp47 expression in HPMC, and PKC as well as ROS mediate MGO-induced VEGF secretion by HPMC. This implies that PKC activation and ROS generation by GDP may constitute important signals for activation of HPMC leading to progressive membrane hyperpermeability and accumulation of extracellular matrix and eventual peritoneal fibrosis.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2006.04a
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• pp.11-13
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• 2006

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.42-48
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• 1998

In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.140-146
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• 2018

Though bile acids have been well known as digestive juice, recent studies have demonstrated that bile acids bind to their endogenous receptors, including Farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (GPBAR1; TGR5) and serve as hormone to control various biological processes, including cholesterol/bile acid metabolism, glucose/lipid metabolism, immune responses, and energy metabolism. Deficiency of those bile acid receptors has been reported to induce diverse metabolic syndromes such as obesity, hyperlipidemia, hyperglycemia, and insulin resistance. As consistent, numerous studies have reported alteration of bile acid signaling pathways in type II diabetes patients. Interestingly, bile acids have shown to activate TGR5 in intestinal L cells and enhance secretion of glucagon-like peptide 1 (GLP-1) to potentiate insulin secretion in response to glucose. Moreover, FXR has been shown to crosstalk with TGR5 to control GLP-1 secretion. Altogether, bile acid receptors, FXR and TGR5 are potent therapeutic targets for the treatment of metabolic diseases, including type II diabetes.