• Title/Summary/Keyword: Leu-7

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Cultivation of Psychrotrophic Lactic Acid Bacteria Isolated from Kimchi in Korean Cabbage-Juice (김치에서 분리한 저온성 젖산균의 배추즙에서의 배양)

  • 소명환;오현진
    • The Korean Journal of Food And Nutrition
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    • v.7 no.4
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    • pp.392-398
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    • 1994
  • The purpose of this study was to predict the actions and roles of 10 strains of representative psychrotrophic lactic acid bacteria, in kimchi fermentation, which were Isolated from kimchi and identified as Leu. mesenteroides subsp. mesenteroides, Leu. mesenteroides subsp. dextranicum, Leu. lactic, Leu. paramesenteroides, Lac. bavaricus and Lac. homahiochii. For this, 0.01% of tactic starters were inoculated in germ free Korean cabbage-juice containing 2.5% NaCl, and then cultivated for 14 days at 1$0^{\circ}C$. All strains grew actively, and reached their stationary phase in 4 days. In death phase, the slopes of curves were much different each other by strains. The acidity increased rapidly between 2 and 4 days, and the pH decreased rapidly between 2 and 3 days. The total acidity was 0.5B~0.75%, the volatile acidity 0.04~0.18% and the pH 3.55~3.85, in final cultures. The cultures of Leuconostocs were better than those of lactobacilli on flavor test. It was thought that the ripening periods of kimchi would be much reduced, and that the over ripening would be also somewhat avoided, when these strains were used as starter bacteria for kimchi and the kimchi was fermented at low temperature.

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Conformation and Biological Activity of Mastoparan B and Its Analogs I

  • 박남규;서정길;구희정;이산나무;Gohsuke Sugihara;김광호;박장수;강신원
    • Bulletin of the Korean Chemical Society
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    • v.18 no.1
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    • pp.50-56
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    • 1997
  • The mode of action of mastoparan B, an antimicrobial cationic tetradecapeptide amide isolated from the hornet Vespa basalis, toward phospholipid bilayers was studied with synthetic mastoparan B and its analogs with individual Ala instead of hydrophobic amino acids (1-Ile, 3-Leu, 6-Leu, 7-Val, 9-Trp, 13-Val, 14-Leu) in mastoparan B. Mastoparan B and its analogs were synthesized by the solid-phase method. Circular dichroism spectra showed that mastoparan B and its analogs adopted an unordered structure in buffer solution. In the presence of neutral and acidic liposomes, most of the peptides took an α-helical structure. The calcein leakage experiment indicated that mastoparan B interacted strongly with neutral and acidic lipid bilayers than its analogs. Mastoparan B also showed a more or less highly antimicrobial activity and hemolytic activity for human erythrocytes than its analogs. These results indicate that the hydrophobic face in the amphipathic α-helix of mastoparan B critically affect biological activity and helical contents.

Lactic Acid Bacteria Isolated from Fermenting Kimchi and Their Fermentation of Chinese Cabbage Juice (김치에서 젖산균의 분리 및 이 세균들의 배추즙액 발효)

  • Shim, Sun-Taek;Kyung, Kyu-Hang;Yoo, Yang-Ja
    • Korean Journal of Food Science and Technology
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    • v.22 no.4
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    • pp.373-379
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    • 1990
  • Lactic acid bacteria(LAB) were isolated from fermenting Kimchi and were cultivated in filter-sterilized Chinese cabbage juice individually or in combination. LAB isolated were Lactobacillus leichimannii, Lac. fermentum, in addition to the already known Leuconostoc mesenteroides, Lac. plantarum, lac. brevis and pediococcus pentosaceus. Lac. leichimannii, Lac. fermentum and Lac. sake, the early lactobacilli, were high in number exceeding $10^4cells/ml$ at 0 time and multiplied up to $10^9cells/ml$ altogether at the 3rd day of kimchi fermentation. When the representative LAB were cultivated singly in Chinese cabbage juice with or without 3.0% NaCl, one strain of Leu. mesenteroides and La. leichmannii were not different in acid producing ability while the other strain of Leu. mesenteroides and Lac. fermentum Lac. plantarum, produced less acid when NaCl was present. When the bacteria in combination were cultivated in Chinese cabbage juice with 3.0% NaCl, the presence of Leu. mesenteroides was essential to eliminate the lag phase in acid production with higher amounts of acid produced than without. The total number of lactobacilli in the mixture of kimchi ingredients was about $2.9{\times}10^4 cells/ml$ while the number of Lac. plantarum was 7.3 cells/ml. The number of Lac. plantarum in individual ingredients were normally in the range between $0.0{\sim}240cells/g$ except garlic sold in ready-to-use form with $9.0{\times}10^3 cells/g$.

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Studies on the Changes of Taste Compounds during Soy Paste Fermentation (III) (된장 숙성 중 정미 성분의 변화에 관한 연구(III))

  • 김미정;이혜수
    • Korean journal of food and cookery science
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    • v.9 no.4
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    • pp.261-265
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    • 1993
  • For the purpose of supplying the information to improve the acceptability of soy paste as the condi-ment, the changes of peptide were determined. The results were as follows; Average peptide length were decreased. It was 102 at 0 day, 15 at 10 day and 4.1 at 180 day. Peptide fraction were the same as in 60 day and 180 day. Low molecular weight peptide were not changed greatly during fermention. Peptide identified in 180 day fermentation were Ala-Ser, Gly-Glu, Glu-Ser, Asp-Glu, Asp- Tyr, Asp-Ala-Ser, Ala-Ser-Glu, Glu-Ser-Ala, and Ala-Lys-Met. In the characteristics of bitter peptide in 180 day fermentation, soy paste itself didn't show bitter taste', solvent extration fraction I'showed bitter taste. After gel chromatography, fraction I, fraction II and fraction III were obtained and fraction II were bitter peptide of low molecular weight. After gel chromatography', solvent extration fraction 2'(water extration) were divided into fraction IV, V, VI,VII and VIII. Fraction IV, V and VI showed bitter taste. Amino acids composition of the fractions showing bitter taste were like that; fr. 1: Glu- (Asp, Pro, Val, lie or Leu)-Met fr. II Pro-(Glu, Val, Phe)-lle or Leu fr. IV: Glu-(Asp, Ala, Tyr, Leu of lie)-Phe fr. V: Ala-(Met, Glu, Pro)-lle or Leu fr. VI: Asp-(Phe, Ser, fly)-Val.

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Kefir 유래의 미생물을 이용하여 제조한 발효유의 특성에 관한 연구

  • Kim, Hyeon-Cheol;Kim, Tae-Jin;Sin, Hui-Cheol;Song, Jin-Uk;Lee, Jong-Ik;Yu, Je-Hyeon
    • Proceedings of the Korean Society for Food Science of Animal Resources Conference
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    • 2004.05a
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    • pp.322-325
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    • 2004
  • Kefir에서 유산균인 Lactobacillus acidophilus와 Lactococcus lactis 그리고 효모인 Candida kefir를 분리하였고, 이를 이용하여 FM(Fermented milk) A, B, C 제조${\cdot}$분석하였다. 유산균 수는 FM B가 $8.6{\times}\;10^9\;cfu/ml$로 가장 많았고, 효모수는 FM C가 $1.3{\times}\;10^7cfu/ml$로 가장 많았다. 알콜 함량은 FM C가 3.2%, FM A가 0.98%, FM B가 0.15% 였다. 아미노산은 FM A에서는 Glu, Pro, Leu, Lys, Asp 등이, FM B에서는 Glu, Leu, Pro, Lys 등이, FM C에서는 Glu, Leu, Pro, Lys 등이 주요 아미노산으로 나타났다. 지방산은 FM A, FM B, FM C 모두 palmitic acid(Cl6:0)와 oleic acid(Cl8:1)가 각각 33.5${\sim}$37.7%와 22.1${\sim}$22.4%의 수준으로 주요 지방산을 차지하였다. 관능검사 결과FM C가 가장 높은 점수를 받았으며, 다음은 FM A, FM B 순이었다.

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Microbiological Analysis of Dongchimi, Korean Watery Radish Kimchi, at the Early and Mid-phase Fermentation

  • Park, Sun-Jung;Chang, Jin-Hee;Cha, Seong-Kwan;Moon, Gi-Seong
    • Food Science and Biotechnology
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    • v.17 no.4
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    • pp.892-894
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    • 2008
  • During dongchimi fermentation at 5 and $25^{\circ}C$, the pH lowered slowly and reached 4.03 at $5^{\circ}C$ after 30 days, whereas it lowered dramatically and reached 3.59 at $25^{\circ}C$ after 2 days. The predominant bacteria were Leuconostoc (Leu.) mesenteroides at $25^{\circ}C$ until day 2 which changed into Lactobacillus (Lb.) plantarum at day 3, analyzed by a culture dependent method with partial 16S rRNA gene sequencing, whereas Leu. mesenteroides occupied predominantly at $5^{\circ}C$ until day 7. In a culture-independent method using a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) with partial 16S rRNA gene sequencing, Lb. algidus was predominant at $5^{\circ}C$ until day 7 and Lb. plantarum occupied predominantly at $25^{\circ}C$ until day 3, which is different from the results of the culture based method, indicating the both methods need to be combined for accuracy. Based on the culture-dependent method, Leu. mesenteroides might be responsible for the early and mid-phase of dongchimi fermentation.

Enhancing the Alginate Degrading Activity of Streptomyces sp. Strain M3 Alginate Lyase by Mutation (Streptomyces sp. M3 알긴산분해효소의 돌연변이에 의한 활성증대)

  • Kim, Hee-Sook
    • Journal of Life Science
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    • v.22 no.1
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    • pp.7-15
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    • 2012
  • A polyguluronate-specific lyase from Streptomyces sp. strain M3 has been previously cloned and characterized. In this study, the M3 alginate lyase gene in the pColdI vector was mutated by site-directed mutagenesis and random mutagenesis to enhance the alginate degrading activity. Six mutants were obtained: Ser25Arg, Phe99Leu, Asp142Asn, Val163Ala, Lys191Glu, and Gly194Cys. Phe99Leu and Lys191Glu mutants completely lost their alginate lyase activity, whereas the alginate degrading activity of Gly194Cys mutant increased by nearly 10 fold. The 3-D protein structure of M3 alginate lyase, which was constructed using the Swiss-Model automodeler, was also compared to the crystal structure of another alginate lyase. A mutated glycine residue was positioned between Gly193 and Tyr195 of the C-terminal conserved sequence, YFKAGXYXQ. A phenylalanine residue (at position 99) and a glycine residue (at position 194) mutated in this study were distant from the active site, but the degrading activity was strongly affected by their mutation.

${\beta}$-1,4-Xylosidase Activity of Leuconostoc Lactic Acid Bacteria Isolated from Kimchi (김치에서 분리된 Leuconostoc 속 젖산균의 ${\beta}$-1,4-xylosidase 효소생산 특성)

  • Jang, Mi-Hee;Kim, Myoung-Dong
    • Korean Journal of Food Science and Technology
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    • v.43 no.2
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    • pp.169-175
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    • 2011
  • The ${\beta}$-xylosidase (EC 3.2.1.37) production capabilities of lactic acid bacteria in the genus Leuconostoc, isolated from a variety of kimchi (fermented vegetables), were examined. The intracellular levels of ${\beta}$-xylosidase were similar to the extracellular levels, when most Leuconostoc lactic acid bacteria were grown in a medium containing xylose as the carbon source. Intracellular ${\beta}$-xylosidase with a maximum activity of $1.2{\pm}0.1units/mL$ (mean${\pm}$standard error) was obtained from Leuconostoc lactis KCTC 13344, which was isolated from fermented Chinese cabbage. The optimum reaction conditions for Leu. lactis KCTC 13344 ${\beta}$-xylosidase activity were pH 6.0 and $30^{\circ}C$, and the addition of most divalent cations, except zinc, to the reaction mixture resulted in a slight increase in enzyme activity. Compared with a media containing other carbon sources, the ${\beta}$-xylosidase activity was 5 times higher when Leu. lactis KCTC 13344 was grown in a medium containing xylose as carbon source. Zymographic analysis indicated that the synthesis of Leu. lactis KCTC 13344 ${\beta}$-xylosidase (approximate size, 64 kDa) is induced by xylose. A maximum intracellular ${\beta}$-xylosidase activity of $7.1{\pm}0.3units/mL$ was obtained in a batch cultivation in an MRS medium containing 30 g/L xylose.

A case of Pfeiffer syndrome with c833_834GC>TG (Cys278Leu) mutation in the $FGFR2$ gene

  • Lee, Min-Young;Jeon, Ga-Won;Jung, Ji-Mi;Sin, Jong-Beom
    • Clinical and Experimental Pediatrics
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    • v.53 no.7
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    • pp.774-777
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    • 2010
  • Pfeiffer syndrome is a rare autosomal dominant disorder characterized by coronal craniosynostosis, brachycephaly, mid-facial hypoplasia, and broad and deviated thumbs and great toes. Pfeiffer syndrome occurs in approximately 1:100,000 live births. Clinical manifestations and molecular genetic testing are important to confirm the diagnosis. Mutations of the fibroblast growth factor receptor 1 ($FGFR1$) gene or $FGFR2$ gene can cause Pfeiffer syndrome. Here, we describe a case of Pfeiffer syndrome with a novel c833_834GC>TG mutation (encoding Cys278Leu) in the $FGFR2$ gene associated with a coccygeal anomaly, which is rare in Pfeiffer syndrome.

Studies on Free Amino Acids Composition of Salted Internal Organs of Several Fishes (어류내장(魚類內臟) 숙성(熟成)젓의 Free Amino Acids 조성(組成)에 관(關)한 연구(硏究))

  • Shin, Dong-Wha;Kim, Hyong-Soo
    • Applied Biological Chemistry
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    • v.9
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    • pp.83-90
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    • 1968
  • In order to elucidate the differences among the parts of internal organs of salted fishes (Chang Zut), five parts of the organs were examined for their chemical constituents including amino acids. The moisture content varied from 59.8% to 72.8% Crude protein; 7.13% to 11.19%, Crude ash; to 16.1%, 24.8%, Sodium chloride; 15.3% to 22.4% and ash; 0.8% to 2.2%. Seven essential amino acids including leucine, isoleucine, phenylalanine, tryptophan, threonine, lysine and methionine except valine were existed in the every part of the organ. The contents of tyrosine and hydroxyproline were relatively high, on the other hand, tryptophan was trace amount in the every parts.

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