• 미생물학회지
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• 제44권1호
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• pp.1-9
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• 2008

본 논문은 벼 흰 잎마름병균인 Xanthomonas oryzae pv. oryzae(Xoo)의 병원성 유전자의 분자유전학적 연구현황을 기술하고자 한다. 또한 국내 고유 벼 흰 잎마름병균 KACC10331의 유전체해독 정보를 기반으로 다른 Xanthomonas의 유전체와 비교 분석함으로써, Xoo의 주요 병원성 유전자의 분자구조를 구명하고자 한다. 이를 통해 Xoo 고유 병원성 유전자 탐색 및 기능 해석을 위한 기초자료를 제공하는데 목적이 있다. Xoo 유전체에는 5개 과(family)에 속하는 9 type의 Insertion sequence(IS)가 611 copy로 존재하고 있으며, 주로 병원성 관련 유전자군 주위에 많이 분포하고 있는 것으로 나타났다. 현재까지 연구가 수행된 주요 병원성 관련 유전자인 hypersensitive response and pathogenicity (hrp) 유전자, extracellular polysaccharide (EPS) 유전자, extracellular enzyme 유전자, lipopolysaccharides (LPS) 유전자, 그리고 avilulence 유전자의 분자유전학적 연구현황을 기술하였다.

• KSBB Journal
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• 제8권2호
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• pp.164-171
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• 1993

Methylomonas mucosa를 이용하여 세포외 다당류의 생산을 알아보았다. 본 미생물은 성장을 위해 메탄올을 탄소원으로 이용하여 세포외 다당류를 생산한다. 효과적인 발효 공정 시스템의 개발올 위해 회 분식, 유가식, 연속식 배양을 수행하여 각각의 당류 에 대한 생산성을 알아보았다. 플라스크 배양에서 메탄올이 약 1 % (v/v) 이상에서 다당류의 생산과 세포의 성장은 저해되었다. 1% (v/v)에서 최대 비성장속도를 나타내었고 C/N 비율이 높을수록 다당류의 생산은 많았다. 다당류의 생산에 $Mg^{2+}$ 이온 농도가 크게 영향을 줌을 확인할 수있었다. 유가식 배양에서는 다당류의 농도가 회분식에 비 해 4배 이상 높았으나 수율은 오히려 감소하였다. 연속주입을 통한 유가식 배양은 간헐적 주업방법보다 생산성이 높았다. 이는 간헐적 주입에서 나타날 수 있는 메탄올에 의한 제한이나 저해가 없었기 때 문으로 보여진다. 연속조엽은 산소 제한을 피하기 위해 순수산소를 공급하였다. 희석률이 O.21h-1까지 증가하여도 수융 과 생산성은 증가하였다. 생산된 다당류 용액의 점도는 다당류의 증가에 따라 지수적으로 증가하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.566-569
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• 2005

tyrosinase 저해 활성 실험 결과 1.2%(w/v) 이상의 농도에서 70% 이상의 저해를 나타내 색소침착에 대한 기능성 화장품 원료로 사용이 가능할 것으로 보이며, ACE 저해 활성 실험에서 1.5% 농도에서 60% 가량의 저해활성을 보여 혈관 변형 치료 및 예방에 효과가 있을 것으로 기대된다. UV 흡수능에서는 UV-B, UV-C의 영역에서 흡수 경향을 나타내며 자외선 차단제의 원료로 사용이 가능할 것으로 기대되며, 또한 bead 형성능을 가지고 있어 약물전달체로서 이용 가능성이 기대된다.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1287-1293
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• 2011

The extracellular polysaccharide (EPS) was isolated from mycelial cultures of Laetiporus sulphureus var. miniatus and purified by DEAE cellulose and Sephadex G-50 column chromatography. The purified EPS (EPS-2-1) was composed of only glucose units and its molecular mass was 6.95 kDa. The chemical structure of EPS-2-1 consisted of a main chain containing ($1{\rightarrow}4$)-Glcp units with branches at the C-6 position of the chain carrying-Glcp-($1{\rightarrow}4$)-linked residues. The effect of purified EPS on immunomodulatory genes and proteins of the Bcl-2 family was observed using cultured U937 human leukemia cells. Of note, the levels of Bax and Bad proteins treated with the EPS (4 mg/ml) were approximately 23- and 18-times higher than those in non-treated cells, respectively. These results may suggest that the EPS purified from the mushroom L. sulphureus is associated with the activation of immunomodulatory mediators, Bax and Bad proteins.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.745-750
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• 2003

Zoogloea ramigera produces an extracellular polysaccharide called zooglan, which adsorbs heavy metals. In the current study, Zoogloea ramigera was cultured in media containing various carbon sources. When different carbon sources were included in the cultivation medium, there was a change in the composition of zooglan that is mainly composed of glucose, galactose, and pyruvic acid. The various zooglan compositions were analyzed by HPLC, and changes in the heavy metal (lead (II) and cadmium) adsorption characteristics relative to a change in the composition were examined using an atomic absorption spectrophotometer. A high adsorption capacity was observed at a pH higher than 3.0. The adsorption of metal ions was the highest at $35^{\circ}C$, and a higher adsorption was obtained with a lower flow rate. Changes in the zooglan composition did result in changes in the heavy metal adsorption characteristics. Furthermore, it was also found that the pyruvic acid content was more important than the glucose or galactose content for heavy metal adsorption.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.794-799
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• 2003

Enzyme-linked immunosorbent assay (ELISA) was developed for the rapid detection of Fusarium species, known as harmful fungi in food. One of the hybridoma cell lines (lB8) which produced a monoclonal antibody (Mab) specific to Fusarium extracellular polysaccharide (EPS) was screened and the Mab was produced and purified. A detection limit of the sandwich ELISA against F. moniliforme EPS was $0.001\;\mu\textrm{g}/ml$ in the standard curve. Among the 59 strains tested, most Fusarium species showed hight reactivity with Mab lB8, even when the culture broths were diluted 100,000 times. On the other hand, the other genera, except A. versicolor and Trichoderma viride, had no reactivity. When 1 to $100\;\mu\textrm{g}$ of F. moniliforme EPS was spiked into rice, potato, and mandarine orange, the average recoveries were 151%, 84%, and 94%, respectively, determined by sandwich ELISA. The correlation coefficients between the EPS levels determined by sandwich ELISA and the dry mycelial weight of the liquid culture of F. moniliforme, as well as between the EPS and colony forming unit in solid culture of potato, were 0.97 and 0.91, respectively.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.764-772
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• 1999

To develop an enzyme-linked immunosorbent assay (ELISA) for detecting mold, we produced anti-mold polyclonal antibodies by immunizing extracellular polysaccharide (EPS) of Aspergillus flavus or Penicillium citrinum in rabbits subcutaneously. Using the purified antibody (Ab) and Ab-HRP conjugate, a sandwich ELISA for EPS was established. The standard curve of the ELISA showed the detection limit for P citrinum EPS to be $0.003{\;}\mu\textrm{g}/ml$. The cross-reactivities of the anti-P citrinum EPS Ab toward components of P citrinum such as EPS, liquid, and solid culture mycelium were 100, 10.5, and 0.58%, respectively, and those toward components of A. flavus such as EPS, liquid and solid culture mycelium, and spore were 300, 0.67, 0.29, and 0%, respectively. When the reactivities toward culture broths of 59 mold strains were tested by the sandwich ELISA, most of the Aspergillus (16 of 18) and Penicillium (14 of 16) strains along with one of the two Cladosporium strains gave positive signals in the culture broths even when diluted 1,000 fold, while the rest of species such as Fusarium, Absidia, Alternaria, and Candida gave negative signals. When the water extracts of 30 corn samples were analyzed by the sandwich ELISA, the EPS in the com could be detected in the concentration range of $0.1-1.6{\;}\mu\textrm{g}/g$.

• BMB Reports
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• 제42권3호
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• pp.172-177
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• 2009

Phosphoglucose isomerase (PGI) is involved in synthesizing extracellular polysaccharide (EPS). The gene encoding PGI in Sphingomonas chungbukensis DJ77 was cloned and expressed in E. coli, and the protein was characterized. The pgi gene from DJ77 is 1,503 nucleotides long with 62% GC content and the deduced amino acid sequence shows strong homology with PGIs from other sources. The molecular masses of PGI subunit and native form were estimated to be 50 kDa and 97 kDa, respectively. Four potentially important residues (H361, R245, E330 and K472) were identified by homology modeling. The mutations, H361A, R245A, E330A, R245K and E330D resulted in decrease in Vmax by hundreds fold, however no significant change in Km was observed. These data suggest that the three residues (H361, R245Aand E330) are likely located in the active site and the size as well as the spatial position of side chains of R245 and E330 are crucial for catalysis.

• BMB Reports
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• 제42권8호
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• pp.523-528
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• 2009

Phosphomannose isomerase (PMI) catalyzes the interconversion of fructose-6-phosphate and mannose-6-phosphate in the extracellular polysaccharide (EPS) synthesis pathway. The gene encoding PMI in Sphingomonas chungbukensis DJ77 was cloned and expressed in E. coli. The pmi gene is 1,410 nucleotides long and the deduced amino acid sequence shares high homology with other bifunctional proteins that possess both PMI and GDP-mannose pyrophosphorylase (GMP) activities. The sequence analysis of PMI revealed two domains with three conserved motifs: a GMP domain at the N-terminus and a PMI domain at the C-terminus. Enzyme assays using the PMI protein confirmed its bifunctional activity. Both activities required divalent metal ions such as $Co^{2+}$, $Ca^{2+}$, $Mg^{2+}$, $Ni^{2+}$ or $Zn^{2+}$. Of these ions, $Co^{2+}$ was found to be the most effective activator of PMI. GDP-D-mannose was found to inhibit the PMI activity, suggesting feedback regulation of this pathway.

• 대한치과의사협회지
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• 제9권12호
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• pp.819-822
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• 1971

For this investigation, author isolated Streptococcus mitis strain SD-9 from the bacterial flora in the human dental plaque, which was incubated in brain-heart infusion media containing 5% sucrose at 37℃ for 24 hours. For the cytochemical demonstration of polysaccharide produced by this strain, a modified thiosemicarbazide osmium method (Critchley et al., 1967) was used. After fixation with this reagent, the harvested cells was suspended in 1% agar for the higher concentration of cells(Kellenberger et al., 1964). And they were dehydrated in the various concentration of ethanol, and embedded in Epon 812(Luft, 1961). Sectioning was done with the Sorvall MT-2 Porter Blum ultramicrotome by means of a glass knife, and the sections were stained with saturated uranyl acetate and lead citrate (Raynolds, 1963). All preparations were examined in a electron microscope, Hitachi HU-ll E-1 type. The morphological features of extracellular polysaccharide produced by Streptococcus mitis strain SD-9 were appeared in 3 structurally different forms, those are, electron dense fibrillar material linearly arranged adjacent to the outer surface of cell wall, highly electron dense globular material adjacent to the outer surface of cell wall, and strutureless fluffy meshwork of possible very fine filament.