• Title/Summary/Keyword: weak acid

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Distribution and Extraction Condition of Endoprotease and Exopeptidase from Viscera of Illex argentinus (원양산 오징어(Illex argentinus) 내장의 endoprotease 및 exopeptidases의 분포 및 추출조건 검토)

  • Kim, Hye-Suk;Heu, Min-Soo;Kim, Jin-Soo
    • Applied Biological Chemistry
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    • v.50 no.4
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    • pp.308-315
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    • 2007
  • For the effective use of squid processing by-products as food resources, the distribution and the extraction condition of endoprotease and exopeptidase from viscera of Illex argentinus were investigated. Crude protein and lipid contents of viscera of Illex argentinus were 17.2% and 16.9%, respectively. Regardless of kinds of extraction solution (water, 1% NaCl, 1% KCl and 1% NaCl- KCl) and extraction times (1-20 h), endoprotease activities from viscera of Illex argentinus on Hb, casein and azocasein (pH 6.0) were higher than those on casein and azocasein of the other pHs, thus indicating that the distribution of protein hydrolysing protease is distinctive in the weak acid pH range. Exopeptidase activities against LeuPNA and ArgPNA at pH 7.5 were relatively higher than endoprotease activity of the same pH. The results suggested that exopeptidase among proteases from viscera of Illex argentinus was reasonable for application in food industry compared to endoprotease. The activity in enzymes from viscera of Illex argentinus was the highest in the exopeptidase extracted with deionized distilled water at room temperature for 6-8 h. The optimal reaction conditions of crude enzyme from viscera of Illex argentinus were 7.5 for pH and $50-55^{\circ}C$ for temperature.

Changes of Quality in Stirred Yogurt during Storage at Various Conditions of Temperature and Shaking (저장온도와 교반조건을 달리한 요구르트의 저장 중 품질변화)

  • Lee, H.J.;Suh, D.S.;Shin, Y.K.;Goh, J.S.;Kwak, H.S.
    • Korean Journal of Food Science and Technology
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    • v.24 no.4
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    • pp.353-360
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    • 1992
  • This study was carried out to investigate the changes of quality in yogurt during delivery and storage. To do this, microbiological, physico-chemical and sensory properties in stirred yogurt were studied at different temperatures $(10^{\circ}C$ & $20^{\circ}C)$ and shakings (100 rpm & 200 rpm for 30 min). Titratable acidity and TCA soluble nitrogen in yogurt were increased in accordance with increase of temperature and time, while pH, lactose and lactic acid bacteria tended to be decreased. Interestingly enough, shaking conditions almost did not influence these studies. In sensory evaluation it showed that acidity was strong and sweetness was weak as increasing the storage temperature and time, but there were no significant differences until 10 days at $10^{\circ}C$ and 3 days at $20^{\circ}C$. Off-flavor was developed after 12 days at $10^{\circ}C$ with only 200 rpm shaking and after 6 days at $20^{\circ}C$ in both shaking conditions. These yogurts were not suitable for consumer. Viscosity in the yogurt became high as the temperature and time were increased. Viscosity was lower in yogurt shaked at 200 rpm than in non-shaked yogurt. Finally, this study indicates that temperature and shaking during delivery of yogurt may be critical in keeping quality of yogurt.

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A Study on the Ultrastructure of the Digestive Organ (Pharynx, Caeca) of Korean Planaria (Dugesia japonica Ichikawa et Kwakatsu) (韓國産 플라나리아(Dugesia japonica Ichikawa et Kawakatsu) 消化器官의 微細構造에 關한 硏究)

  • 장남섭;김우갑
    • The Korean Journal of Zoology
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    • v.28 no.4
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    • pp.211-226
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    • 1985
  • The ultrastructure of the digestive organ of Korean Planaria (Dugesia japonica) is studied by light microscope and transmission electron microscope. 1. Pharynx The epithelium surrounding pharyngeal lumen has a number of microvilli on the free surface. The epithelial cells contain PAS-positive granules which are 0.4 to 0.6 $\\mum$ in size. They also contain hundreds of vesicles and vacuoles. The pharyngeal epithelium of the external surface surrounded by pharyngeal cavity possesses a number of cilia and microvilli on the free surface. A number of muscle bundles are found in the pharyngeal tissue. The parietal epithelium surrounding pharyngeal cavity have microvilli and electron-dense secretory granules. 2. Caeca The cells which constitute the cecal epithelium are divided into four kinds of cells. 1) Phagocytic cell : These cells are characterized by presence of a number of lysosomes. These cells have highly developed mitochondria, polyribosomes and granular endoplasmic reticulum of which cisternae are distended. 2) Granular club cell : These cells contain round granules 5 $\\mum$ in diameter which show strong PAS-positivity and weak eosinophilia. The cells have highly developed granular endoplasmic reticulum. 3) Storage cell : These cells include thousands of glycogen granules in the cytoplasm. These cells also have second kind of round granules which are 1.4 to 3 $\\mum$ in size and exhibit PAS-positive reaction. 4) Immature storage cell : These cells have a large nucleus and contain a small number of granules which have PAS-positive granules and a few lipid droplets. Several chromatoid bodies are found in the cytoplasm around the nucleus.

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Study on the Contamination of Pseudomonas tolaasii in Oyster Mushroom (느타리버섯에서의 Pseudomonas tolaasii오염 연구)

  • 이혜영;장금일;김광엽
    • Journal of Food Hygiene and Safety
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    • v.16 no.3
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    • pp.232-240
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    • 2001
  • One hundred twenty five bacterial isolates were obtained from the brown blotch-diseased oyster mushrooms collected from markets. Among them, 45 were determined as pathogenic bacteria and white line forming organisms(WLFO) were 6 strains and white line reaction organisms (WLRO) were 6 strains. All of the white line forming isolates were identified as Pseudomonas tolaasii which is a known pathogen of brown blotch disease of oyster mushroom by GC-MIS(Gas chromatography-microbial identification system). Six of the white line reacting organisms were identified as P. chlomraphis, P. fluorescens biotype A and type C. The rest of them were P gingeri, P. agarici, P. fluorescens biotype B, P. chloroyaphis, non-pathogenic P. tolaasii, P. putida biotype A and B etc. For spectrum of activity of tolaasin, culture filtrates from pathogenic isolates were examined by browning of mushroom tissue and pitting of mushroom caps. The weak pathogenic bacteria didn't induce browning or pitting of mushroom tissue. On the other hand, strong pathogenic isolates showed browning and pitting reaction on mushroom. An extracellular toxin produced by P. tolaasii, was investigated. The hemolysis activity test of 6 strains identified as P. tolaasii were 0.8∼0.9 at 600 nm and 3 strains of WLRO were 0.9∼1.0 and Pseudomonas app. were 1.0∼1.2. Observation of fresh mushroom tissue using confocal laser scanning microscopy was carried out for images of optical sectioning and vertical sectioning. Also images of brown blotch diseased oyster mushroom tissue after contamination P. tolaasii was obtained by CLSM.

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Characterization and Expression Profile Analysis of a New cDNA Encoding Taxadiene Synthase from Taxus media

  • Kai, Guoyin;Zhao, Lingxia;Zhang, Lei;Li, Zhugang;Guo, Binhui;Zhao, Dongli;Sun, Xiaofen;Miao, Zhiqi;Tang, Kexuan
    • BMB Reports
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    • v.38 no.6
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    • pp.668-675
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    • 2005
  • A full-length cDNA encoding taxadiene synthase (designated as TmTXS), which catalyzes the first committed step in the Taxol biosynthetic pathway, was isolated from young leaves of Taxus media by rapid amplification of cDNA ends (RACE). The full-length cDNA of TmTXS had a 2586 bp open reading frame (ORF) encoding a protein of 862 amino acid residues. The deduced protein had isoelectric point (pI) of 5.32 and a calculated molecular weight of about 98 kDa, similar to previously cloned diterpene cyclases from other Taxus species such as T. brevifolia and T. chinenisis. Sequence comparison analysis showed that TmTXS had high similarity with other members of terpene synthase family of plant origin. Tissue expression pattern analysis revealed that TmTXS expressed strongly in leaves, weak in stems and no expression could be detected in fruits. This is the first report on the mRNA expression profile of genes encoding key enzymes involved in Taxol biosynthetic pathway in different tissues of Taxus plants. Phylogenetic tree analysis showed that TmTXS had closest relationship with taxadiene synthase from T. baccata followed by those from T. chinenisis and T. brevifolia. Expression profiles revealed by RT-PCR under different chemical elicitor treatments such as methyl jasmonate (MJ), silver nitrate (SN) and ammonium ceric sulphate (ACS) were also compared for the first time, and the results revealed that expression of TmTXS was all induced by the tested three treatments and the induction effect by MJ was the strongest, implying that TmTXS was high elicitor responsive.

Influence of Salts on Consolidation of Nebra Sandstone (네브라 사암의 강화처리에 미치는 염의 영향)

  • Do, Jin-Young
    • Journal of Conservation Science
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    • v.18 s.18
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    • pp.89-96
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    • 2006
  • Surface layers of stone cultural properties including the soluble salt need consolidation because they are mostly very weak. There is a lot of research on the penetration depth of consolidant in stone and the effect of consolidant on mechanical stability of deteriorated structure. But some conservation experiences show that consolidation with silicic acid ester is not successful on salt contaminated stone cultural properties. In this study, in order to assess the influence of soluble salts$(CaSO_4\;2H_2O,\;NaNO_3)$ on the efficiency of consolidation on the deteriorated stone cultural properties(Nationalgalerie, Berlin, Germany) sandstone samples have been soaked with the salts solution. The impregnation of consolidant based on ethyl filicate have been afterwards carried out on these samples. As a result, it confirms that the soluble salts act as a preventer or consolidation. They fill up the pores in the stone and prevent that sufficient amount of consolidant enter deeply into the stone. According to this result, if use silicic ethyl ester as a consolidant for the research object which is built by Nebra sandstone, desalination is necessary before the treatment with consolidant. But it is also reported by other researches that some soluble salts improve the consolidation effect. Therefore it should be necessary to pre-study about salt and its harmfulness before the consolidation treatment. In order to consolidate without the aggravative damage in salt contaminated stone cultural heritage, we must first of all study the relations among salt, stone and consolidant.

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D-Amphetamine Causes Dual Actions on Catecholamine Release from the Rat Adrenal Medulla

  • Lim, Geon-Han;Na, Gwang-Moon;Min, Seon-Young;Seo, Yoo-Seok;Park, Chan-Won;Lim, Dong-Yoon
    • The Korean Journal of Physiology and Pharmacology
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    • v.9 no.1
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    • pp.45-53
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    • 2005
  • The present study was designed to examine the effect of d-amphetamine on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Damphetamine $(10{\sim}100{\mu}M$), when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced the CA secretory responses evoked by ACh ($5.32{\times}10^{-3}$ M), excess $K^+$ ($5.6{\times}10^{-2}$ M, a membrane depolarizer), DMPP ($10^{-4}$ M, a selective neuronal nicotinic $N_n-receptor$ agonist) and McN-A-343 ($10^{-4}$ M, a selective $M_1-muscarinic$ agonist) only for the first period (4 min), although it alone has weak effect on CA secretion. Moreover, d-amphetamine ($30{\mu}M$) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase only for the first period (4 min). However, in the presence of high concentration ($500{\mu}M$), d-amphetamine rather inhibited the CA secretory responses evoked by the above all of secretagogues. Collectively, these experimental results suggest that d-amphetamine at low concentrations enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization, but at high concentration it rather inhibits them. It seems that d-amphetamine has dual effects as both agonist and antagonist at nicotinic receptors of the isolated perfused rat adrenal medulla, which might be dependent on the concentration. It is also thought that these actions of d-amphetamine are probably relevant to the $Ca^{2+}$ mobilization through the dihydropyridine L-type $Ca^{2+}$ cha$N_n$els located on the rat adrenomedullary chromaffin cell membrane and the release of $Ca^{2+}$ from the cytoplasmic store.

Fungicidal Activity Enhancement of KNF-1002 Against Barley Powdery Mildew by Facilitating Foliar Uptake and Deposition (KNF-1002의 경엽 침투성과 부착량 증진에 의한 보리 흰가루병 방제 효과)

  • Yu, Ju-Hyun;Choi, Gyung-Ja
    • The Korean Journal of Pesticide Science
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    • v.14 no.3
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    • pp.272-279
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    • 2010
  • KNF-1002, a new fungicide candidate, is very effective for protecting crops against plant diseases, but its curative activity against barley powdery mildew is negligible due to its weak penetrability into plant leaf. To select the most efficient activator and, at the same time, spreade-sticker, foliar uptake and deposit of aqueous spray formulations containing non-ionic or anionic surfactants and fatty acid alkyl esters as an adjuvant were assessed by using Congo Red method. In the absence of activator, only 0.1% of the applied active ingredient was absorbed by barley leaves 24 h after spraying with an aqueous acetone containing KNF-1002 100 mg/L. But, non-ionic surfactants (500 mg/L), such as heptaethylene glycol monooctadecenyl ether (OE-7), dodecaethylene glycol monohexadecyl ether (CE-12), so facilitated KNF-1002 uptake that the uptake was increased up to 48.5%. To wheat plant, the addition of surfactants in spray solution of KNF-1002 also increased the foliar uptake and deposition of active ingredient, but its efficiency varied according to the kind of fatty alcohol moiety of polyoxyethylene surfactant. KNF-1002 formulations containing nonaethylene glycol monododecyl ether (LE-9) as an activator and spreader-sticker showed remarkable increases of fungicidal activity against barley powdery mildew.

Studies on Removal of Water Pollutants by Aquatic Plants - I. Removal of Organic Matter by Water Hyacinth and Factors Affecting It's Growth (수생식물(水生植物)을 이용(利用)한 수질오염원제거(水質汚染源除去)에 관(關한) 연구(硏究) - 제1보(第1報) 부레옥잠의 유기물(有機物) 제거효과(除去效果) 및 생장(生長)에 미치는 제요인(提要因))

  • Pyon, Jong-Yeong;Lee, Kyu-Seung;Lee, Jong-Sik
    • Korean Journal of Weed Science
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    • v.5 no.2
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    • pp.143-148
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    • 1985
  • Water hyacinth, unused and tropical plant was examined in order to know the feasibility of application for purification of municipal drainage and industrial wastewater. This plant was effective to remove the COD from wastewater, although its removal ability was dependent on the organic sources. The effects of pH, NaCl concentration, water temperature and shading condition on the growth of water hyacinth were investigated. The optimum ranges of pH were weak acid- neutral, of water temperature were 17-$21^{\circ}C$, and unshading condition was better. The rapid propagation of this plant was also observed during hot summer season.

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Biodegradation of Phenanthrene by Transformant Trametes versicolor MrP1 (구름버섯의 형질전환체 Trametes versicolor MrP1에 의한 Phenanthrene의 생분해)

  • Choi, Yun-Seong;Choi, Hyoung-Tae;Song, Hong-Gyu
    • Korean Journal of Microbiology
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    • v.43 no.4
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    • pp.273-278
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    • 2007
  • As a model compound of PAHs (polycyclic aromatic hydrocarbons) phenanthrene has been regarded as a toxic material, mutagen and carcinogen in various animals. Biodegradation conditions of phenanthrene such as pH, temperature, shaking speed, stabilizer and cofactor of degrading enzymes were investigated with Trametes versicolor and its transformant T. versicolor MrP1 in YMG medium, minimal medium and soil microcosm. T. versicolor MrP1 can overexpress mrp gene encoding Mn-repressed peroxidase that is involved in fungal degradation. Biodegradations of phenanthrene by T. versicolor and T. versicolor MrP1 were optimally performed in conditions of weak-acid (pH 6.0), $30^{\circ}C$, shaken culture and medium containing 5 mM veratryl alcohol or tryptophan. In these optimal conditions, biodegradation of phenanthrene by T. versicolor MrP1 is 31% higher than that of wild type strain in a minimal medium for 20 days. Biodegradation of phenanthrene by T. versicolor MrP1 was also higher than that of wild type in soil microcosm. T. versicolor MrP1 can be a excellent candidate for the bioremediation of PAHs contaminated environments.