• KSBB Journal
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• 제26권1호
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• pp.33-40
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• 2011

Anti-diabetic effect of the exopolysaccharides (EPS) produced from submerged mycelial culture of Cordyceps sinensis (Cs) was studiedin a type II diabetic animal model (C57BL/6J ob/ob). This study was designed to determine whether Cs-EPS improves clinical symptoms of type II diabetes in ob/ob mice. After Cs-EPS treatment at doses of 200 mg/kg body weight, the fasting blood glucose levels decreased by 47% after 7 weeks compared with those of the control mice. According to the oral glucose tolerance test, the glucose levels recovered its baseline after 120 min in Cs-EPS-treated mice, although the blood glucose levels increased significantly after 30 min. On the other hand, the control group (not-treated) did not recovered its initial level of glucose after 120 min. Furthermore, food intake, body weight, total plasma cholesterol and triglyceride concentrations in ob/ob mice treated with Cs-EPS were significantly decreased, compared with those in control ob/ob mice. Cs-EPS treatment increased significantly the plasma insulin level and the expression of leptin mRNA in adipose tissue of Cs-EPS-treated ob/ob mice. From these results, it is demonstrated that Cs-EPS could be effective for regulating normal blood glucose levels by increasing the amounts of plasma insulin and leptin expression in ob/ob mice, indicating that this compound could be a candidate material as a dietary supplement to control hyperglycemia in patients suffering from type II diabetes.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1095-1100
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• 2008

The role of exopolysaccharides (EPSs) from a plant growth-promoting rhizobacterium, Burkholderia gladioli IN26, on elicitation of induced systemic resistance was investigated. A purified EPS induced expression of PR-1a::GUS on tobacco and elicited induced resistance against Colletotrichum orbiculare on cucumber. The maximum level of disease protection was noted when seeds were soaked in 200 ppm of the EPS. Our results indicate that EPS from specific rhizobacteria can elicit induced resistance and suggest that bacterial EPS might be a useful elicitor of resistance under field conditions.

• 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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• 제26권3호
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• pp.452-460
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• 2016

Acid stress can affect the viability of probiotics, especially Bifidobacterium. This study aimed to improve the acid tolerance of Bifidobacterium longum BBMN68 using adaptive evolution. The stress response, and genomic differences of the parental strain and the variant strain were compared by acid stress. The highest acid-resistant mutant strain (BBMN68m) was isolated from more than 100 asexual lines, which were adaptive to the acid stress for 10^th, 20^th, 30^th, 40^th, and 50^th repeats, respectively. The variant strain showed a significant increase in acid tolerance under conditions of pH 2.5 for 2 h (from 7.92 to 4.44 log CFU/ml) compared with the wild-type strain (WT, from 7.87 to 0 log CFU/ml). The surface of the variant strain was also smoother. Comparative whole-genome analysis showed that the galactosyl transferase D gene (cpsD, bbmn68_1012), a key gene involved in exopolysaccharide (EPS) synthesis, was altered by two nucleotides in the mutant, causing alteration in amino acids, pI (from 8.94 to 9.19), and predicted protein structure. Meanwhile, cpsD expression and EPS production were also reduced in the variant strain (p < 0.05) compared with WT, and the exogenous WT-EPS in the variant strain reduced its acid-resistant ability. These results suggested EPS was related to acid responses of BBMN68.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1266-1273
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• 2008

Lactic acid bacteria (LAB) with antimicrobial activity and high exopolysaccharide (EPS) production ability isolated from sourdough were studied for their fermentation characteristics as potential new starter cultures. The values of pH, titratable acidity, and viable cell counts were $4.06{\pm}0.009-4.50{\pm}0.015,\;0.787{\pm}0.020%-1.172{\pm}0.018%,\;and\;8.78{\pm}0.08-8.98{\pm}0.06$ log CFU/ml, respectively. In order to select probiotics with a high survival rate in the gut, isolates were tested to assess resistance against the artificial gastric acid and bile juice. Viable LAB counts were significantly (p<0.05) affected by the acidity. At pH 2.0, the total declines in the initial bacterial counts were 4.52$\pm$0.07 log for S. thermophilus St-Body-1, >7.98$\pm$0.03 log for E. flavescens DU-10, >7.95$\pm$0.05 log for E. faecium DU-12, and 3.15$\pm$0.06 log for L. amylovorus DU-21. Among the strains, L. amylovorus DU-21 was the only strain that had bile tolerance under simulated gastrointestinal conditions. In order to improve EPS production by L. amylovorus DU-21, the influence of carbon source was studied. When glucose was used as a carbon source, EPS production dramatically increased to 17.19$\pm$0.28 g/l (p<0.05). The maximum cell growth (10.012$\pm$>0.012 log CFU/ml) and EPS production (18.71$\pm$0.19 g/l) were achieved when 15 g/l of glucose was employed as the carbon source.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.560-567
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• 2008

An efficient method to produce water-soluble polysaccharides from Lentinus lepideus is described. The productivity of both endopolysaccharides (PPS) and exopolysaccharides (EPS) was compared under various culture conditions. The effect of treating their own PPS and EPS on immune cytokine production was also studied in relation to culture factors. High yield production of EPS required a moderate culture temperature $(25^{\circ}C)$ as well as long culture period (16-20 days). In contrast, PPS production required a high culture temperature $(30^{\circ}C)$ and short culture period (8 days). Most of the carbon sources did not affect polysaccharides and mycelial production except for sucrose. Immune cytokine levels in the EPS treatment varied among carbon sources or culture periods. PPS did not appear to affect much on the production of cytokines, regardless of the culturing factors, except for the culture period. These results suggest that the optimal culture conditions for L. lepideus vary according to culture purposes, and different culture conditions should be used for different targets including mycelial biomass, EPS, and PPS. Whereas the immunomodulating activitiy of EPS appeared to be affected by culture conditions in L. lepideus, that of PPS did not.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.452-459
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• 2003

본 실험을 수행하기 위해 EPS를 생산하지 않는 Lactobacillus paracasei KLB58의 돌연변이주를 NTG mutagenesis 방법을 사용하여 선별하였다. 선별된 돌연변이주의 숙주에 대한 부착능을 연구하기 위해 세포 표면의 소수성의 변화에 관하여 연구가 진행되었다. 정량적인 측정을 위해 hydrocarbon의 한 종류인 hexadecane을 소수성층으로 사용하여 세포와 함께 섞이는 kinetics를 측정하였다. 실험결과 KLB58의 돌연변이주는 야생형에 비해 세포표면이 상대적으로 높은 소수성을 나타내었다.

• 미생물학회지
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• 제30권6호
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• pp.450-455
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• 1992

대전 지역에서 자생하는 벌노랑이 (Lotus corniculatus var. japonicus) 의 뿌리혹으로부터 생장속도가 빠른 (fast-growing) 5균주를 분리하였다. 분리된 공생균주들은 형태적, 생리적 특성 및 뿌리혹형성 실험을 통하여 이 균주들은 Rhizobium loti 로 동정되었다. 분리균주로 접종시킨 벌노랑이 유식물에서 뿌리혹을 형성하였으며, 대조구와 비교하였을 때 정상적인 성장을 하는 것으로 보아 질소고정능을 갖는 (effect) 뿌리혹을 형성함을 알 수 있었다. 유도된 뿌리혹으로부터 재분리된 공생균주의 형태절 특성 및 항생제 내성에 대한 조사로부터 이들 뿌리혹은 1차 분리균주에 의해 형성된 것임을 알 수 있었다. 또한 이들은 Lotus corniculatus 에서도 질소고정능을 갖는 뿌리혹을 형성하였다. 분리균주 중 R. loti TUS2, TUS5 그리고 TUS8 은 calcofluor-binding exopolysaccharide(EPS) 를 생성하였다.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.388-390
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• 2004

본 연구는 유산균(Lactobacillus fermentum, Lab. acidophilus, Lab. brevis)과 효모(Candida kefyr, Cryptococcus albidus, Pichia ohmeri)등이 주요 균총인 티벳버섯 배양액에서 crude EPS를 분리하여, 로타바이러스의 MA-104 세포감염 억제효과를 측정하였다. 분리된 crude EPS는 0.0026${\sim}$0.363%의 농도에서 MA-104 세포에 대해 독성효과가 없었다. 로타바이러스 Wa, S2, YO의 MA-104 세포 감염에 대해 EPS 0.0026%의 농도에서는 9.11${\sim}$20.06%의 억제율을 보였고, EPS 0.33%의 농도에서는 23.69${\sim}$38.09%의 억제율을 보였다.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.291-294
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• 2004

본 연구는 EPS 생성 유산균을 이용한 stirred 요구르트 제조의 기초 자료로 활용하고자 실시하였다. EPS 분리 실험결과에서 발효 온도가 낮을수록 더 많은 EPS가 생성하고, 발효 12시간과 24시간에 많은 EPS를 생성하는 것으로 관찰되었다. 점도는 EPS 함량과 무관하게 발효 시간이 증가할수록 증가하였으며, $40^{\circ}C$, 발효 30시간에 가장 높은 점도가 측정되었고, syneresis는 $37^{\circ}C$에서 30시간 발효한 요구르트가 가장 적은 것으로 관찰되었다. 경도와 접착성은 발효가 진행될수록 증가한 반면에 점착성과 탄력성은 발효가 진행될수록 감소하였으며, 관능검사 결과에서는 $37^{\circ}C$, 24시간 발효한 요구르트가 가장 높은 수치를 나타내었다.