• 한국미생물·생명공학회지
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• 제30권1호
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• pp.8-14
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• 2002

Pseudomonas sp. S-47은 xylXYZLTE 유전자에 의하여 암호화되는 효소군에 의하여 4CBA를 분해하여 5-chloro-2-hydroxymuconic semialdehyde(5C-2HMS)를 생성하는데, 본 연구에서는 이 5C-2HMS의 다음 분해과정을 확인하였다. xylXYZLTE 유전자와 5-chloro-2-hydroxymuconic semialdehyde dehydrogenase(5C-2HMSD)를 암호화하고 xylG 유전자를 포함하는 재조합 균주인 pCSS202로부터, xylG 유전자를 포함하는 재조합 플라스미드 pENV5를 만들었다. 이 플라스미드는 2-hydroxymuconic semialdehyde, 3-chloro-muconate, 2-hydroxy-6-oxohepta-2,4-dienoate, 2-hydroxy-5-methylmuconic semialdehyde와 같은 aromatic compound 에서 분해능을 나타냈으며, 그 중 5C-2HMS에서 가장 높은 분해능을 나타내었다. 또한 5C-2HMSD를 암호화하는 유전자인 xylC의 염기서열을 분석한 결과, 약 1,600 bp의 염기와 486개의 amino acid residue를 갖고있는 것을 확인하였다. P. sp. S-47의 xylG 유전자를 비교 분석한 결과 P. putida CF600, P. putida G7과 P. putida mt-2 등의 5C-2HMS dehydro-genase와 85％ 이상의 amino acid homology를 보여주었다.

• Journal of Microbiology and Biotechnology
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• 제20권5호
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• pp.946-949
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• 2010

The effects of two different sugars (glucose and xylose) on the expression levels and patterns of the xylose reductase (xyl1), xylitol dehydrogenase (xyl2), and xylulokinase (xyl3) genes were analyzed using Pichia stipitis. A significant increase in mRNA levels of xyl1 was observed after 6 h growth in culture conditions using xylose as a sole carbon source, but expressions of the three genes were not influenced by normal culture media with glucose. In addition, expressions of xyl2 and xyl3 were not observed during the entire culture period during which xylose was added. It also was found that the expression level of xyl1 increased as a function of the xylose concentration (40, 60, and 80 g/l) used in this study, indicating that xyl1 expression sensitively responded to xylose in the culture media. Although the induced level of xyl2 increased slightly after 48 h in the xylose-supplemented culture conditions, the expression of xyl2 was not observed in the xylitol-supplemented culture conditions. Finally, considering the expression of each gene in response to glucose or xylose, the absolute expression levels of the three genes indicate that xyl1 is induced primarily by exposure to xylose.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1252-1258
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• 2016

1,3-Propanediol (1,3-PD) is a valuable platform compound. Many studies have shown that the supplement of NADH plays a key role in the bioproduction of 1,3-PD from Klebsiella pneumoniae. In this study, the xylA and xylB genes from Escherichia coli were overexpressed individually or simultaneously in K. pneumoniae to improve the production of 1,3-PD by cofermentation of glycerol and xylose. Compared with the parent strain, the xylose consumption was significantly increased by the introduction of these two genes. The 1,3-PD titers were raised from 17.9 g/l to 23.5, 23.9, and 24.4 g/l, respectively, by the overexpression of xylA and xylB as well as their coexpression. The glycerol conversion rate (mol/mol) was enhanced from 54.1% to 73.8%. The concentration of 2,3-butanediol was increased by 50% at the middle stage but drastically decreased after that. The NADH and NADH/NAD⁺ ratio were improved. This report suggests that overexpression of xylA or xylB is an effective strategy to improve the xylose assimilation rate to provide abundant reducing power for the biosynthesis of 1,3-PD in K. pneumoniae.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.700-709
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• 2024

Polyhydroxybutyrate (PHB) production from lignocellulosic biomass is economically beneficial. Because lignocellulosic biomass is a mixture rich in glucose and xylose, Escherichia coli, which prefers glucose, needs to overcome glucose repression for efficient biosugar use. To avoid glucose repression, here, we overexpressed a xylose regulator (xylR) in an E. coli strain expressing bktB, phaB, and phaC from Cupriavidus necator and evaluated the effect of xylR on PHB production. XylR overexpression increased xylose consumption from 0% to 46.53% and produced 4.45-fold more PHB than the control strain without xylR in a 1% sugar mixture of glucose and xylose (1:1). When the xylR-overexpressed strain was applied to sugars from lignocellulosic biomass, cell growth and PHB production of the strain showed a 4.7-fold increase from the control strain, yielding 2.58 ± 0.02 g/l PHB and 4.43 ± 0.28 g/l dry cell weight in a 1% hydrolysate mixture. XylR overexpression increased the expression of xylose operon genes by up to 1.7-fold. Moreover, the effect of xylR was substantially different in various E. coli strains. Overall, the results showed the effect of xylR overexpression on PHB production in a non-native PHB producer and the possible application of xylR for xylose utilization in E. coli.

• 생명과학회지
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• 제23권7호
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• pp.863-868
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• 2013

Bacillus sp. HY-20균주 유래 endoxylanase를 코드하는 XylP 유전자를 효모에서 발현시키기 위해 두 개의 발현 플라스미드 pG-xylP와 pGMF-xylP를 구축하였다. 이들 플라스미드는 endoxylanase의 분비발현을 위해 각각 다른 분비서열인 XylP 유전자의 자체 분비서열(XylP s.s)과 최적화된 $MF{\alpha}$ 분비서열($MF{\alpha}_{opt}$ s.s)을 가지고 있으며, S. cerevisiae SEY2102와 FY833균주에 형질전환되어 그 분비활성이 비교 조사되었다. 재조합 endoxylanase는 분비발현시스템과 숙주세포에 따라 23.7~70.1 unit/ml의 활성으로 효모 세포에서 성공적으로 발현되었고, 그 중 SEY2102/pGMF-xylP 형질전환주를 이용해 baffled-flask 배양을 실시한 결과 최대 88.1 unit/ml의 endoxylanase 활성을 보임을 확인하였다. 대부분의 재조합 endoxylanase는 세포 외 분획에 효율적으로 분비 생산되었으며, $MF{\alpha}_{opt}$ 분비서열이 XylP 유전자의 자체 분비서열보다 endoxylanase를 더 효율적으로 분비시킴을 확인할 수 있었다. 그러므로 본 연구에서 개발된 발현시스템은 효모를 숙주세포로 하여 많은 양의 세포 외 endoxylanase의 생산을 가능하게 하고, 바이오에탄올 생산 및 산업적 응용에도 유용하게 사용 될 수 있으리라 기대된다.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.191-193
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• 2021

Lactococcus lactis is a fermentative lactic acid bacterium that is used extensively in food fermentations. The L. lactis strain K_LL005 was isolated from the grasshopper (Oxya chinensis sinuosa) gut in Korea. In this study, we reported the complete genome sequence of Lactococcus lactis K_LL005. The final complete genome assembly consist of one circular chromosome (2,375,093 bp) with an overall guanine + cytosine (G + C) content of 35.0%. Annotation results revealed 2,281 protein-coding sequences (CDSs), 19 rRNAs, and 68 tRNA genes. Lactococcus lactis K_LL005 has a gene encoding xylose metabolism such as xylR, xylA, and xylB (xylRAB).

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.90-90
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• 2002

The purpose of this study was to investigate the effect of kind and combination of sugars on the viability and acrosome damage of post-thaw spermatozoa in canine. The extender used was Tris-citric acid extender (Tris-buffer) supplemented with 20% Egg-yolk, 8% glycerol, 1% Equex STM paste, and 70 mM sugars such as monosaccharide (fructose and xylose) and disaccharide(trehalose). To evaluate of sugar combination, the sugars supplemented in Tris-buffer were combined such as single (fructose, xylose, trehalose), two combinations (Fruc+Tre, Fruc+xyl, Tre+xyl) and three combinations (Fruc+Tre+Xyl). The concentration of sperm collected were adjusted of 50${\times}$10$\^$6/ per straw for freezing. The frozen spermatozoa were thawed at 37$^{\circ}C$ for 1 min and then analysis for CASA program in Livestock Improvement Main Center, NACF. The motility of post-thaw spermatozoa in Fruc+Tre was higher than those in fructose, trehalose, xylose, Fru+xyl, Tre+xyl and Fru+Tre+Xyl (79％ vs. 63, 66, 70, 71, 74 and 75%). The progressive motility after CASA analysis in Fuc+Tre group was also higher than those in fructose, trehalose, xylose, Fru+xyl, Tre+xyl and Fru+Tre+Xyl (67% vs. 53, 57, 60, 61, 62 and 64%). The acrosome damage of post-thaw spermatozoa stained was not significantly different among treatment groups such as fructose, trehalose, xylose, Fru+Tre, Fru+xyl, Tre+xyl and Freu+tre+xyl (17.7, 18.3, 28.0, 17.0, 19.7, 20.0 and 19.0%). The results indicated that the motility and progressive motility of post-thaw spermatozoa in Fru+Tre group was better, and acrosome normality was not different among all groups. The use of Tris-buffer supplemented with Fru+Tre as sugar for frezing of canine spermatosoa could be better and apply to semen banking and artificial insemination.

• Applied Biological Chemistry
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• 제39권6호
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• pp.430-436
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• 1996

대장균에서 xylose isomerase(XI) 생산의 조절양상을 밝히기 위한 연구의 일환으로 유도물질인 xylose에 의한 XI 생산유도 및 glucose에 의한 이화물 억제 양상을 조사하였다. XI 생산 유전자인 xylA 유전자의 발현을 조절하는 xylR 유전자가 염색체에 존재하는 상태에서 xylA 유전자가 고복제수 유래의 플라스미드에 존재하는 경우 (pEX202/DH77)와 저복제수 유래의 플라스미드에 존재하는 경우(pEX102/DH77)에는 염색체에 존재하는 경우 (JM109)보다 0.4% xylose 첨가에 의한 XI의 유도생산이 각각 1.9 및 1.7배 정도 증가하였다. 염색체에 존재하는 xylR 유전자에 의해 생산된 xylR유전자 산물이 xylA 유전자가 플라스미드에 존재할 경우에도 염색체에 존재할때와 마찬가지로 작용하는 것으로 나타났다. 형질전환주 pEX202/DH77과 pEX102/DH77 및 친주 JM109에서 다 같이 0.2% glucose 첨가에 의해 완전히 XI 유도생산이 억제되었으며 이와같은 glucose에 의한 이화물 억제는 1 mM cAMP의 첨가로 해제되었다. DM 최소배지에서 xylose에 의한 XI 유도시 1 mM CAMP를 첨가하면 0.4% xylose만 첨가했을때 보다 XI 생산이 1.7 내지 2배 정도 증가하었다. Xylose isomerase와 cAMP 생산 변이주(xyl, cya ; TP2010)에 xylA 유전자를 형질전환시킨 pEX13/TP2010은 xylose 첨가로 Xl가 유도생산되지 않았고 cAMP를 함께 첨가해야만 XI가 유도되었다. 이와같이 대장균의 xylA 유전자에서 XI의 생산조절에는 xylose이외에 cAMP도 필수적인 효과물질임을 알 수 있었다.

• 미생물학회지
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• 제33권2호
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• pp.92-96
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• 1997

Pseudomonas sp. strain DJ77로부터 클로닝한 catechol 분해와 관련된 phnDEFG 유전자들이 존재하는 pHENX7에서 phnF 유전자의 염기서열을 밝혔다. Extradiol dioxygenase 유전자인 phnE와, 2-hydroxymuconic semialdehyde dehydrogenase를 생산하는 phnG 유전자 사이에 존재하는 유전자 phnF는 432 bps로 된 하나의 open reading frame(ORF)으로 존재하였고, 여기서 유추한 아미노산은 143개로 분자량 13,859 dalton의 polypeptide를 만들어 내고 있다. phnF 유전자는 Sphingomonas sp. strain HV3 catE 유전자 부위와 sphingomonas yanoikuyae B1의 xylE와 xylG 사이에 존재하는 ORF 부위의 염기서열과 각각 99%, 68.6%의 상동성을 가지고 있었다. 또한 PhnF 단백질의 아미노산서열은 citrobacter freundii DSM30040의 orfY 부위의 아미노산서열과 62.3%의 상동성이 있었다.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.564-567
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• 2000

A recombinant Saccharomyces cerevisiae, transformed with the genes encoding xylose reductase (XYL1) and xylitol dehydrogenase (XYL2) orginated from Pichia stipitis CBS 5776, was developed to directly convert xylose to ethanol. A fed-batch fermentation with the recombinant yeast produced 8.7 g ethanol/l with a yield of 0.13 g ethanol/g xylose consumed.