• Molecules and Cells
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• 제39권4호
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• pp.358-366
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• 2016

The digestive system is gaining interest as a major regulator of various functions including immune defense, nutrient accumulation, and regulation of feeding behavior, aside from its conventional function as a digestive organ. The Drosophila midgut epithelium is completely renewed every 1-2 weeks due to differentiation of pluripotent intestinal stem cells in the midgut. Intestinal stem cells constantly divide and differentiate into enterocytes that secrete digestive enzymes and absorb nutrients, or enteroendocrine cells that secrete regulatory peptides. Regulatory peptides have important roles in development and metabolism, but study has mainly focused on expression and functions in the nervous system, and not much is known about the roles in endocrine functions of enteroendocrine cells. We systemically examined the expression of 45 regulatory peptide genes in the Drosophila midgut, and verified that at least 10 genes are expressed in the midgut enteroendocrine cells through RT-PCR, in situ hybridization, antisera, and 25 regulatory peptide-GAL transgenes. The Drosophila midgut is highly compartmentalized, and individual peptides in enteroendocrine cells were observed to express in specific regions of the midgut. We also confirmed that some peptides expressed in the same region of the midgut are expressed in mutually exclusive enteroendocrine cells. These results indicate that the midgut enteroendocrine cells are functionally differentiated into different subgroups. Through this study, we have established a basis to study regulatory peptide functions in enteroendocrine cells as well as the complex organization of enteroendocrine cells in the Drosophila midgut.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1690-1694
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• 2003

The large and rapid changes of glucose utilization in lactating mammary tissue in response to changes in nutritional state must be largely related by external signal of insulin. This also must be related with the quantity and composition of the diet in vivo. To characterize the mode of growth factors and gut regulatory peptides with insulin, in vitro experiment was conducted with HC11 cells. All the growth factor alone and the combinations of growth factors significantly (p<0.05) increased in glucose uptake. Insulin, EGF and IGF-1 exhibited a stimulation of glucose uptake for at least 24 h. Furthermore, the highest (p<0.05) synergistic effect was shown in EGF plus IGF-1 and the second synergistic effect in insulin plus EGF while no synergistic effect was found between insulin and IGF-1. However, the gut regulatory peptides neither potentiated nor inhibited the action of insulin on glucose uptake. Although growth factors did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, RT-PCR analysis indicated that the growth factors significantly (p<0.05) increased the expression of GLUT1. The growth factors are therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.

• Asian-Australasian Journal of Animal Sciences
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• 제24권4호
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• pp.500-508
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• 2011

Forty-four Gansu Alpine Fine-wool lambs were used to study changes in the activities of three gastric and five pancreatic enzymes under grazing conditions between 0 and 56 days of age. The lambs were slaughtered on days 0, 3, 7, 14, 21, 28, 42 and 56, the abomasal contents, mucosa and pancreas were immediately removed and placed into liquid nitrogen and enzyme activities were determined. Gastric enzyme (chymosin, pepsin and pregastrc esterase) activities were relatively high at birth, especially chymosin, but decreased quickly between day 0 and 21. The activity of pepsin changed insignificantly with increasing age. There was no significant change in the pancreatic enzyme activities (trypsin, chymotrypsin, ${\alpha}$-amylase, lipase and lactase). The activity of trypsin was relatively higher than that of the other pancreatic enzymes, and lactase activity was low. These ontogenic patterns might be under the control of many gut regulatory peptides, the plasma concentrations of which changed simultaneously. Some gastric and pancreatic enzymes were correlated with plasma concentrations of these gut regulatory peptides.

• 대한수의학회지
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• 제42권3호
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• pp.289-297
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• 2002

쏘가리 (Siniperca scherzeri Steindachner)의 위장관에 존재하는 내분비세포의 부위별 분포 및 출현빈도를 포유류의 peptide에 대한 7종류의 항혈청을 사용하여 면역조직화학적 방법으로 관찰하였다. 쏘가리의 위장관은 근위부에서부터 원위부까지 위, 소장 및 대상으로 3 등분 하였으며, 다양한 종류의 항혈청에 면역반응성을 나타내는 면역반응세포들이 상피세포 사이와 위샘 또는 장샘에서 관찰되었다. 상피세포 사이에서는 대부분의 면역반응세포들은 장 내강까지 신장되어 있는 긴 세포질 돌기를 함유한 방추형의 개방형 세포 (open type cell)로 관찰되었으며, 세포질 돌기 없이 원형 또는 타원형의 형태를 나타내는 폐쇄형 세포 (close type cell)들이 위 부위에서 소수 관찰되었다. 본 실험에서는 serotonin, somatostatin, pastrin, cholecystokinin (CCK)-8 및 human pancreatic polypeptide (HPP) 면역반응세포들이 관찰되었으나, insulin 및 glucagon 면역반응세포들은 관찰되지 않았다. Serotonin 및 somatostatin 면역반응세포들은 위 부위에 국한되어 각각 중등도 및 다수의 출현빈도로 관찰되었다. 또한 gastrin 면역반응세포들은 위와 소장에서 출현하였으며, 각각 소수 및 중등도의 출현빈도를 나타내었고, CCK-8 면역반응세포들은 소장에 국한되어 중등도의 출현빈도를 나타내었다. 한편 HPP 면역반응세포들은 위와 소장에서 다수 관찰되었다. 이상에서 쏘가리 위장관 내분비세포들의 부위별 분포 및 출현 빈도는 다른 경골어류에 비해 특이한 양상을 나타내는 것으로 관찰되었다.

• 한국육종학회지
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• 제42권4호
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• pp.339-343
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• 2010

Post-translational covalent modifications by small molecules or peptides remodel target proteins. One such modification, made by ubiquitin or small ubiquitin-related modifier (SUMO), is a rapidly expanding field in cell signaling pathways. Ubiquitin attachment controls the turnover and degradation of target proteins while SUMO conjugation regulates their activity and function. Recent studies report many examples of cross-talk between ubiquitin and SUMO pathways, indicating that the boundary is no longer clear. Here, we review recent progress concerning how ubiquitin and SUMO participate in new regulatory roles in plant cell, and how ubiquitination and sumoylation control plant growth and development.

• BMB Reports
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• 제38권2호
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• pp.121-127
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• 2005

Drosophila protects itself from infection by microbial organisms by means of its pivotal defense, the so-called innate immunity system. This is its sole defense as it lacks an adaptive immunity system such as is found in mammals. The strong conservation of innate immunity systems in organisms from Drosophila to mammals, and the ease with which Drosophila can be manipulated genetically, makes this fly a good model system for investigating the mechanisms of virulence of a number of medically important pathogens. Potentially damaging endogenous and/or exogenous challenges sensed by specific receptors initiate signals via the Toll and/or Imd signaling pathways. These in turn activate the transcription factors Dorsal, Dorsal-related immune factor (Dif) and Relish, culminating in transcription of genes involved in the production of antimicrobial peptides, melanization, phagocytosis, and the cytoskeletal rearrangement required for appropriate responses. Clarifying the regulatory interactions between the various pathways involved is very important for understanding the specificity and termination mechanism of the immune response.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1300-1308
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• 2012

The 5'-adenosine monophosphate-activated protein kinase (AMPK) is a key part of a kinase-signaling cascade that acts to maintain energy homeostasis. The objective of this experiment was to investigate the possible effects of fasting and refeeding on the gene expression of hypothalamic AMPK, some appetitive regulating peptides and lipid metabolism related enzymes. Seven-day-old male broiler (Arbor Acres) chicks were allocated into three equal treatments: fed ad libitum (control); fasted for 24 h; fasted for 24 h and then refed for 24 h. Compared with the control, the hypothalamic gene expression of $AMPK{\alpha}2$, $AMPK{\beta}1$, $AMPK{\beta}2$, $AMPK{\gamma}1$, Ste20-related adaptor protein ${\beta}$ ($STRAD{\beta}$), mouse protein $25{\alpha}$ ($MO25{\alpha}$) and agouti-related peptide (AgRP) were increased after fasting for 24 h. No significant difference among treatments was observed in mRNA levels of $AMPK{\alpha}1$, $AMPK{\gamma}2$, LKB1 and neuropeptide Y (NPY). However, the expression of $MO25{\beta}$, pro-opiomelanocortin (POMC), corticotropin-releasing hormone (CRH), ghrelin, fatty acid synthase (FAS), acetyl-CoA carboxylase ${\alpha}$ ($ACC{\alpha}$), carnitine palmitoyltransferase 1 (CPT-1) and sterol regulatory element binding protein-1 (SREBP-1) were significantly decreased. The present results indicated that 24 h fasting altered gene expression of AMPK subunits, appetite regulation peptides and lipometabolism related factors in chick's hypothalamus; the hypothalamic FAS signaling pathway might be involved in the AMPK regulated energy homeostasis and/or appetite regulation in poultry.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1163-1168
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• 2016

Cholangiocarcinoma (CCA) is the bile duct cancer which constitutes one of the important public health problems in Thailand with high mortality rate, especially in the Opisthorchis viverrini (a parasite risk factor for CCA) endemic area of the northeastern region of the country. This study aimed to identify potential biomarkers from the plasma peptidome by CCA patients. Peptides were isolated using 10 kDa cut-off filter column and the flow-through was then used as a peptidome for LC-MS/MS analysis. A total of 209 peptides were obtained. Among these, 15 peptides were concerned with signaling pathways and 12 related to metabolic, regulatory, and biosynthesis of secondary metabolite pathways. Five exclusive peptides were identified as potential biomarkers, i.e. ETS domain-containing transcription factor ERF (P50548), KIAA0220 (Q92617), phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit beta isoform isoform 1 (P42338), LP2209 (Q6XYC0), and casein kinase II subunit alpha (P19784). Three of these biomarkers are signaling related molecules. A combination of these biomarkers for CCA diagnosis is proposed.

• 대한수의학회지
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• 제41권4호
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• pp.477-484
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• 2001

붕어 (Carassius auratus Linnaeus)의 장에 존재하는 소화관 내분비세포의 부위별 분포 및 출현빈도를 포유류의 peptide에 대한 10종류의 항혈청을 사용하여 면역조직화학적 방법으로 관찰하였다. 붕어의 장은 근위부에서부터 원위부까지 5 등분했으며 (Segments I~V), 대부분의 면역반응세포들은 상피부분의 상피세포들 사이 공간에서 관찰되었으며, 장 내강까지 신장되어 있는 긴 세포질돌기를 함유한 방추형의 개방형 세포 (open type cell)들이 주로 관찰되었으나, 세포질돌기 없이 원형 또는 타원형의 형태를 나타내는 폐쇄형 세포 (close type cell)들 역시 소수 관찰되었다. 본 실험에서는 somatostatin, cholecystokinin (CCK)-8 및 pancreatic polypeptide (PP) 면역반응세포들이 관찰되었으나, serotonin, glucagon, chromogranin A, secretin, vasoactive intestinal peptide (VIP), substance P 및 bombesin 면역반응세포들은 관찰되지 않았다. 한편 somatostatin 면역반응세포들은 장의 가장 근위부인 Segment I에 국한되어 극소수 관찰되었으며, CCK-8 면역반응세포들은 장의 근위부인 Segment I과 II에서 소수 또는 극소수의 빈도로 관찰되었다. PP 면역반응세포들 역시 장의 근위부에서 중간 부위인 Segment I에서부터 III에 걸쳐 중등도 또는 극소수의 빈도로 출현하였다. 이상에서 붕어 위 내분비세포들의 부위별 분포 및 출현 빈도는 다른 위가 없는 경골어류 (stomachless teleost)에서의 보고들과 유사하였으나, 독특한 분포를 나타내는 면역반응세포들 역시 관찰되었다.

• BMB Reports
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• 제29권4호
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• pp.386-392
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• 1996

A Saccharomyces cerevisiae Protein Tyrosine Phosphatase, PTP1, was expressed from an Escherichia coli expression system and milligram quantities of active PTP1 were purified chromatographically. The substrate specificity of the recombinant PTP1 was probed using synthetic phosphotyrosine-containing peptides corresponding to the regulatory phosphorylation sites of the yeast MAP kinase homologues $Fus3_{176-186}$, $Kss1_{179-189}$, and $Hog1_{170-180}$. Peptide sequences derived from the MAP kinase homologues were chosen arbitrarily as starting points for sequence variation studies even though they are not likely to be candidates for physiological substrates of PTP1. Phosphotyrosyl-$Hog1_{170-180}$ peptide showed a $K_M$ value of 877 ${\mu}M$ and phosphorylated $Kss1_{179-189}$ and $Fus3_{176-186}$ peptides showed lower $K_M$ values of 74 ${\mu}M$ and 51 ${\mu}M$ each. To study the effect of sequence variations of the peptide, amino acids of the undecapeptide $Hog1_{170-180}$ (DPQMTGpYVSTR) were sequentially substituted by an alanine residue. More extensive variations of each amino acid revealed positional importance of each amino acid residue. Based on these results, we derived a peptide sequence (DADEpYDA) that is recognized by PTP1 with an affinity ($K_M$ is 4 ${\mu}M$) significantly higher than that of the peptides derived from the phosphorylation sites of Fus3, Kss1, and Hog1.