• 제목/요약/키워드: thermophilus

검색결과 243건 처리시간 0.021초

Bacillus stearothermophilus $\beta$-Xylosidase 유전자의 염기 서열 결정 및 분석 (Sequence Analysis of $\beta$-Xylosidase Gene from Bacillus stearothermophilus)

  • 오현주;최용진
    • 한국미생물·생명공학회지
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    • 제22권2호
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    • pp.134-142
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    • 1994
  • The neucleotide sequences of the xylA gene encoding $\beta $-xylosidase of Bacillus stearothermophilus and is its flanking regions were datermined. Three open reading frame(ORFs) were found, one of which(ORF1) appeared to code for the $\beta $-xylosidase. The 1830 base pair ORF1 encoded 609 amino acids starting from a TTG initiation codon. The molecular weight deduced from the nucleotide sequence(68 KD) was in agreement with that estimated by SDS-polyacrylamide gel electrophoresis of the purified enzyme(66 KD). The Shine-Dalgarno sequence(5'-AGGAGG-3') was found 11 bp upstream of the initiation codon. Further 15 bp upstream, there observed a potential transcription initiation signals. The putative -10 sequence(CATAAT) and -35 sequence(TTGTTA) coresponded closely to the consensus sequences for Bacillus subtilis RNA polymerase with major sigma factor. The guanine-plus-cytosine content of the coding region of the xylA gene was 56mol% while that of the third position of the codons was 63 mol%. Based on the comparison with the amino acid sequences of several other carbohydrate degrading enzymes, two conserved regions, possibly participating in the catalytic mechamism of $\beta $-xylosidase xylA, were identified in 278-298 and 329-350 regions of the translated xylA gene. The nucleotide sequence of the xylA was found to exhibit no homology to any other genes so far reproted.

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Regulation of $\beta$-Xylosidase (XylA) Synthesis in Bacillus stearothermophilus

  • Cho, Ssang-Goo;Choi, Yong-Jin
    • Journal of Microbiology and Biotechnology
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    • 제8권1호
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    • pp.14-20
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    • 1998
  • Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides +124 to +136 and CRE-2:+247 to +259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

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Synbiotic Synthesis of Oligosaccharides During Milk Fermentation by Addition of Leuconostoc Starter and Sugars

  • Seo, Dong-Mi;Kim, So-Young;Eom, Hyun-Ju;Han, Nam-Soo
    • Journal of Microbiology and Biotechnology
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    • 제17권11호
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    • pp.1758-1764
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    • 2007
  • Synthesis of oligosaccharides during milk fermentation was attempted by inoculating Leuconostoc citreum with Lactobacillus casei, Lb. delbrueckii subsp. bulgaricus, and Streptococcus thermophilus as starters. Dextransucrase of Ln. citreum worked as a catalyst for the transglycosylation reaction of sugars; sucrose was added as the glucose donor, and lactose or maltose acted as the acceptor compound for the reaction. When 4% sucrose was added in milk, glucosyl-lactose was synthesized (about 1%, w/v) after 1-2 days of fermentation at 15 or $25^{\circ}C$. Alternatively, when sucrose and maltose (2% each, w/v) were added, panose (about 1 %, w/v) and other isomaltooligosaccharides were made in a day at $15-35^{\circ}C$. Growth patterns of lactobacilli and streptococci starters were not affected by the coculture of leuconostoc starter, but the rate of acid synthesis was slightly slowed at every temperature. Addition of sugars in milk did not give any adverse effect on the lactate fermentation. Accordingly, the use of leuconostoc starter and addition of sugars in milk allowed the production of oligosaccharides-containing fermented milk, and application of this method will facilitate the extensive development of synbiotic lactate foods.

전통발효식품에서 분리한 유산균의 항균활성 및 프로바이오틱스 기능성 연구 (Antibacterial Activity and Probiotic Properties of Lactic Acid Bacteria Isolated from Traditional Fermented Foods)

  • 강창호;한설화;김용경;정율아;백남수
    • KSBB Journal
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    • 제32권3호
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    • pp.199-205
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    • 2017
  • The aim of this study was to investigate probiotic characteristics and fermentation profile of selected lactic acid bacteria (LAB) isolated from traditional fermented foods. Antibacterial activity against various pathogens, acid and bile salt tolerance, cell hydrophobicity, and antibiotic resistance were examined. 16S rRNA sequencing was carried out to identify eight presumptive LAB isolates. In general, all identified LAB (Enterococcus faecium MG89-2, Lactobacillus plantarum MG207, L. paracasei MG310, L. casei MG311, Streptococcus thermophilus MG510, L. bulgaricus MG515, L. helveticus MG585, and L. fermentum MG590) showed strong antimicrobial activity. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All selected strains tested were sensitive to chloramphenicol, tetracycline, and ampicillin, whereas resistant to nalidixic acid and kanamycin.

자색고구마 첨가 요구르트의 제조 및 특성 (Preparation of Yogurt from Milk Added with Purple Sweet Potato)

  • 전승호;이상욱;신용서;이갑성;류일환
    • 한국식품영양학회지
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    • 제13권1호
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    • pp.71-77
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    • 2000
  • New type yogurt base were prepared from milk added with skim milk powder or purple sweet potato, and fermented by lactic acid bacteria (Streptococcus thermophilus and Bifidobacterium infantis, 1:1, v/v). The yogurt proudcts were evaluated for acid production(pH, titratiable acidity), number of viable cell, viscosity, sensory properties, and color value. The composition of some organic acids was also analyzed by GC. The acid production slightly decrerased by addition with purple sweet potato. There was no significant difference in viable cell counts between control (yogurt added with only skim milk powder) and yogurt added with purple sweet potato, and viable cell counts of all samples were above 9.08 log cfu/ml. Viscosity of yogurt added with purple sweet potato(36,800∼46,000 centipoise) was higher than that of yogurt added with only skim milk powder(32,200 centipoise). The overall sensory score of yogurt added with purple sweet potato(38.6%, dry base) was the best of tested yogurt. The major organic acid of yogurt added with purple sweet potato was lactic acid. its content was 0.997∼1.203%. malic acid, succinic acid, oxalic acid, and fumaric acid were analyzed out a little. Lightness and yellowness decreased by addition with purple sweet potato but redness increased. Total color difference($\Delta$E) with yogurt addition with purple sweet potato and only skim milk powder were very high(above 11.46).

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오갈피(Acanthopanax sessiliflorum Seeman) 추출액이 유산균의 생육에 미치는 영향 (A Study on Effect of Acanthopanax sessiliflorum Seeman Water Extract on the Growth of Lactic Acid Bacteria)

  • 김선영;박근실;이수한;정승원;노완섭
    • 동아시아식생활학회지
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    • 제16권3호
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    • pp.357-363
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    • 2006
  • This study examined the effect of medicinal herbs on the growth of 3 strains of lactic starter cultures in a MRS broth by adding a 0, 1, 3, 5, and 10% water extract. The pH, titratable acidity and OD of lactic acid bacteria were investigated in order to obtain fundamental knowledge for the development a new product, box thorn yogurt. In the case of adding the Acanthopanax sessiliflorum Seeman water extract, Streptococcus thermophilus was largely activated by the addition of the 5% extract. The growth of Lactobacillus acidophilus was activated by the extracts but it was depressed by the addition of the 3% Acanthopanax sessiliflorum Seeman water extract. Compared with the control, the growth of Bifidobacterium longum was largely activated by the addition of the 10% extract but it was depressed by the addition of the 5% Acanthopanax sessiliflorum Seeman water extract.

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Bioconversion of Straw Into Improved Fodder: Mycoprotein Production and Cellulolytic Acivity of Rice Straw Decomposing Fungi

  • Helal, G.A.
    • Mycobiology
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    • 제33권2호
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    • pp.90-96
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    • 2005
  • Sixty two out of the sixty four species of fungal isolates tested could produce both $exo-{\beta}1,4-gluconase\;(C_1)$ and $endo-{\beta}1,4-gluconase\;(C_x)$ on pure cellulose and rice straw as carbon source in Czapek's medium. Fifty-eight and fifteen species were able to grow at $25^{\circ}C$ and at $45^{\circ}C$, respectively. Eleven species could grow at both $25^{\circ}C$ and $45^{\circ}C$ while, four species appeared only at $45^{\circ}C$. The most cellulolytic species at $25^{\circ}C$ was Trichoderma koningii producing 1.164 $C_1$ (mg glucose/1 ml culture filtrate/1 hr) and 2.690 $C_x$ on pure cellulose, and 0.889 $C_1$, and 1.810 $C_x$ on rice straw, respectively. At $45^{\circ}C$, the most active thermotolerant species were Aspergillus terreus, followed by A. fumigatus. Talaromyces thermophilus was the highest active thermophilic species followed by Malbranchea sulfurea. Most of these species were also active in fermentation of rice straw at 25 and $45^{\circ}C$ (P<0.05). The most active ones were T. koningii, A. ochraceus and A. terreus, which produced 201.5, 193.1 and 188.1 mg crude protein/g dry straw, respectively.

A Probiotic Preparation Duolac-Gold Ameliorates Dextran Sulphate Sodium-induced Mouse Colitis by Downregulating the Expression of IL-6

  • Yoon, Hyunho;Yoon, Yeo-Sang;Kim, Min-Soo;Chung, Myung-Jun;Yum, Do-Young
    • Toxicological Research
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    • 제30권1호
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    • pp.27-32
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    • 2014
  • Probiotics are live microorganisms that confer a health benefit on the host. Duolac-Gold is a mixture of seven probiotic bacteria containing three species of Bifidobacteria, two species of Lactobacillus, and Streptococcus thermophilus. The aim of this study was to assess the anti-inflammatory effects of Duolac-Gold in an inflammatory bowel disease (IBD) mouse model. IBD was induced by administering 1.5% dextran sulfate sodium (DSS) for 10 days. After induction of DSS-induced colitis, Duolac-Gold was orally administered at three different concentrations. Interestingly, Duolac-Gold treatment accelerated IBD healing, and anti-inflammatory activity was assessed by weight loss, length of the colon, and a microscopic damage score by histology. The expression of inflammatory related cytokines was measured in colon tissues and serum. Of these cytokines, the expression of interleukin-6 decreased remarkably after Duolac-Gold treatment. Taken together, these results suggest that Duolac-Gold treatment is effective in IBD healing by regulating IL-6.

유산균배양액의 유체역학적 성질에 관한 연구 (Study on the Rheological Properties of the Lactic acid Fermented Milk)

  • 정후길;강국희
    • 한국식품위생안전성학회지
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    • 제5권1호
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    • pp.35-40
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    • 1990
  • 유산균이 생성하는 다당류에 관한 연구의 일환으로서 Str. themophilus 와 Lb. bulgaricus를 10% 환원탈지유와 12% 환원전지유에 배양하면서 다당류 생성에 따른 우유 배양액 점도의 경시적 변화 및 그의 유체역학적인 특성에 대하여 조사하였다. 1. Str. themophilus 510의 10% 탈지유 배양액의 의가소성 유체의 유동양식을 가장 강하게 나타냈다. 한편 14% 농도에서 가장 높은 점도의 경시적 변화 및 그의 유체역학적인 특성에 대하여 조사하였다. 1. 12% 전지유배양액의 경우 의가소성유체의 유동양식을 나타내지만 탈지유 배양액에 비해서 현저한 점도의 저하를 나타냈다. 1. Str. themophilus 510 배양액의 최대 점조도 계수와 최소 유동지수는 각각 43, 0.09 이며 Lb. bulgaricus는 35, 0.09이다.

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농후 발효유에 의한 여대생의 변비개선 효과 (Effect of Drinking Fermented Milk on the Improvement of Defecation in Constipated Female Students)

  • 이선영;신정란;임상호
    • 한국생활과학회지
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    • 제12권2호
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    • pp.265-273
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    • 2003
  • The aim of this study was to investigate the effect d concentrated fermented milk on the improvement of defecation in female students with constipation. This yogurt was fermented with Bifidobacterium, L. acidophilus, and S. thermophilus and supplemented with oligosaccharides, dietary fiber, and yeast and mushroom extracts. 44 female students with constipation were sampled as subjects and fed 150ml fermented milk per day for 2 weeks period. After each defecation, the subjects were examined for the status of stool evacuation by questionnaires. The frequency of stool evacuation, fecal amount, time spending for evacuation, fecal color and shape, and refreshing feeling after evacuation were remarkably improved after ingestion of fermented milk for 2 weeks. These effects were greater in the heavy constipation group than in the mild group. The fecal odor did rot decrease significantly after 2 weeks of intake of fermented milk, but the odor thended to decrease after the intake of fermented milk These results indicated that the ingestion of concentrated fermented milk is effective to improve the constipation.

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