• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.43-48
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• 2008

The present study investigated the effect of physiologically active polysaccharide (SP1) isolated from Salicornia herbacea on streptozotocin-induced diabetic rats. Male Spraque-Dawley rats were divided into four groups which were normal control group (NC), diabetic control group (DC), diabetic CSP group (DCSP), and diabetic SP1 group (DSP1). Animals were administrated with 2% experimental drinks for 6 weeks. The levels of glucose, triglyceride, total cholesterol, and high density lipoprotein (HDL)-cholesterol in the serum were measured before and after intake of test compounds. The levels of glucose and triglyceride in the DSP1 were significantly lower than those in the DC by 25% and 20%, respectively. The levels of total cholesterol and high density lipoprotein (HDL)-cholesterol in the DSP1 were similar to those in the DC. These results suggest that SP1 substantially exhibit anti-hyperglycemic and anti-hypertriglyceridemic activity in diabetic rats. Therefore SP1 is believed to show remarkable anti-diabetic effect on streptozotocin-induced diabetic rats.

• Journal of the Korean earth science society
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• v.21 no.3
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• pp.250-257
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• 2000

Two species of fusulinids, viz., Pseudoschwagerina paraborealis and Quasifusulina sp. are described from the limestone core sample(90-B-1). The core sample was obtained from Imgokri, Boeungun, Chungcheongbukdo, Korea. Recognition of Pseudoschwagerina helped the authors to establish the Pseudoschwagerina Zone. Pseudoschwagerina paraborealis has been reported from the Bamchi Formation of Yeongweol coalfield in Korea and also from the Asselian and Sakmarian strata in Eurasia. The occurrence of Pseudoschwagerina paraborealis in the Boeun coalfield demonstrates the existence of the early Permian strata that are equivalent to the Bamchi Formation of Yeongweol coalfield. The authors report Quasifusulina sp. which indicates the early Permian period as well as Pseudoschwagerina paraborealis. It is the first time that the species of early Permian fusulinids are identified from the Boeun coalfield.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.670-680
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• 2018

Acanthophysium sp. KMF001, a wood rotting fungus, produces a strong crude enzyme complex that efficiently produces simple sugars from wood. The transcriptomic analysis of Acanthophysium sp. KMF001 identified 14 genes for putative glycoside hydrolases. Among them, isotig01043 was expressed heterogeneously in Escherichia coli BL21(DE3), and the expressed protein exhibited an endo-${\beta}$-1,4-xylanase activity which showed the optimum reaction at pH 5.0 and $30^{\circ}C$. The enzyme kinetic values of $K_m$ and $V_{max}$ were 25.92 mg/ml and $0.628{\mu}mole/mg/ml$, respectively. The enzymatic characteristics of the expressed xylanase showed a typical fungal xylanase. However, the bioinformatics analysis suggested that the protein encoded by isotig01043 was a novel xylanase based on a low identity when it was compared with the closest protein in the NCBI database and a similar protein domain with GH16_fungal_Lam16A_glucanase, which had not been earlier suggested as a xylanase.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1706-1715
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• 2018

Several non-methylotrophic bacteria have been reported to improve the growth and activity of methanotrophs; however, their interactions remain to be elucidated. We investigated the interaction between Methylocystis sp. M6 and Microbacterium sp. NM2. A batch co-culture experiment showed that NM2 markedly increased the biomass and methane removal of M6. qPCR analysis revealed that NM2 enhanced both the growth and methane-monooxygenase gene expression of M6. A fed-batch experiment showed that co-culture was more efficient in removing methane than M6 alone (28.4 vs. $18.8{\mu}mol{\cdot}l^{-1}{\cdot}d^{-1}$), although the biomass levels were similar. A starvation experiment for 21 days showed that M6 population remained stable while NM2 population decreased by 66% in co-culture, but the results were opposite in pure cultures, indicating that M6 may cross-feed growth substrates from NM2. These results indicate that M6 apparently had no negative effect on NM2 when M6 actively proliferated with methane. Interestingly, a batch experiment involving a dialysis membrane indicates that physical proximity between NM2 and M6 is required for such biomass and methane removal enhancement. Collectively, the observed interaction is beneficial to the methanotroph but adversely affects the non-methylotroph; moreover, it requires physical proximity, suggesting a tight association between methanotrophs and non-methylotrophs in natural environments.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.537-543
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• 2005

Subtilisin (EC 3.4.21.14) is the major extracellular alkaline serine protease of Bacillus species. Previously, we found that subtilisins did not migrate in the electrophoretic field in the Laemmili buffer system due to their high pI values (over 8.8); however, it formed a 'binding mode' at the top of the separating gel [5]. Utilizing this characteristic, four subtilisins from Bacillus sp. strains (e.g., B. subtilis 168, B. subtilis KCTC 1021, B. amyloliquefaciens KCTC 3002, and Bacillus sp. DJ-1 and DJ-4) were easily and quickly identified by an over-running electrophoretic technique with a miniscale culture supernatant (less than 20 ml) without any column chromatographic steps. Two subtilisins (DJ-l and a recombinant version) from Bacillus sp. DJ-l were characterized, and the enzymatic properties were determined by SDS-fibrin zymography and densitometric analysis. Based on this observation, the recombinant pro-subtilisin DJ-l showed the same 'binding mode,' similar to native subtilisin DJ-l. On the other hand, mature subtilisin DJ -1 without pro-peptide showed no enzymatic activity.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.47-53
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• 1993

Antibiotics KG-431A and KG-431B were isolated from the fermentation broth of the Clostridium sp. KH-431. As we have shown previously, only KG-431B was successful to recrystallize. These antibiotics showed antimicrobial activities against broad spectrum of bacteria and fungi. KG-431B also showed anticancer activity against some animal tumor cells according to the SRB method. Physico-chemical properties of KG-431B were determined using UV, IR, NMR and Mass spectra. It was identified to be 3-Indole propionic acid and the structure of the KG-431A is currently under investigation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.107-124
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• 2000

A bacterial strain No. HB-5, which was capable of producing a pretense in the culture conditions, was isolated from the soil . The pretense was purified from cultural filtrate of Bacillus sp. HB-5 by membrane ultrafiltration and DEAE- cellulose chromatography, gel filtration on Sephadex G-100. The molecular weight was estimated to be 60k4a. The optimal pH and temperature for the activity of the purified pretense pH were 11 and 5$0^{\circ}C$ , respectively. The enzyme was stable within a pH range 8-12 and up to 6$0^{\circ}C$ . The enzyme activity was highly inhibited by PMSF at 1mM. The proteolytic actions of pretense and papain on human epidermis keratins which are major protein impurities on the skin, were compared. The bacterial pretense degraded more effectively than papain. Product containing 2% protease exhibited 21% increase on the skin coloration index. These results suggest that cosmetic product containing pretense produced by Bacillus sp. HB-5 could remove the adherent keratin layer and then make a softer skin.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.160-166
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• 2004

The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$PO$_4$, 0.05% The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % $(KH_2PO_4$, 0.05% $MgSO_4{\cdot}7H_2O$, 0.2% L-asparagine, pH 4.5, and the optimal inoculum size and shaking speed were $1.5{\times}10^6$ spores/50 m1 medium and 150 rpm, respectively. On optimal conditions, 4.1 g/l of the cell mass was obtained at 28$^{\circ}C$ for 3 days. The mycelium were inoculated on 500 g of steamed rice using vinyl bag ($30.6{\times}44$ cm) and incubated at $30^{\circ}C$, 85% humidity for 21 days. Lactone form monacolin K was rapidly increased for 2 days and reached highest concentration of monacolin K (2,930 mg/kg) for 15 days, and monacolin K was decreased after 15 days.

• Natural Product Sciences
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• v.21 no.4
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• pp.261-267
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• 2015

Compared to their terrestrial and marine counterparts, little is known about the capacity of freshwater-derived actinomycete bacteria to produce novel secondary metabolites. In the current study, we highlight the disparities that exist between cultivation-independent and -dependent analyses of actinomycete communities from four locations in Lake Michigan sediment. Furthermore, through phylogenetic analysis of strains isolated from these locations, we identified a Streptomyces sp., strain B025, as being distinct from other Streptomyces spp. isolated from sediment. Upon fermentation this strain produced a rare class of eight-membered lactone secondary metabolites, which have been for their antitumor properties. We used spectroscopic and chemical derivitization techniques to characterize octalactin B (1) in addition to its corresponding novel, unnatural degradation product (2).

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.21-21
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• 2002

극축을 따라 나타나는 결정학적 이방성이 결정성장에 미치는 영향을 알아보기 위해서 SiO₂막 위에서 GaN 미소결정들을 성장시켰다. 미소결정을 구성하는 면들은 PBC이론이 예측한 바와 같이 {10-11], {0001}, {10-10}이었다. 극축인 c축을 따라서 현저한 성장의 이방성을 관찰할 수 있었으며 (0001)면이 매우 빨리 성장 하여 사라지는 현상을 확인하였다. 이것은 sp3결합에서 나타나는 고립전자쌍이 (000-1)면의 성장을 저지함으로서 나타나는 현상이라고 생각된다. 성장 중 결정표면의 전자상태에 따라 수소흡착이 일어날 수 있는데, 특히 {10-11}면과 같은 한 개의 전자로 이루어진 sp3결합 팔은 매우 많은 양의 수소를 흡착하여 {10-11}면의 성장을 저지한다. 따라서 ＋c축 방향의 경우 빨리 성장하고 수소흡착을 위한 전자가 없는 (0001)면 대신 {10-11}면이 외형상 매우 중요한 면으로 나타나게 된다. 저온에서는 {10-10}, {10-12}면들도 나타났으며 극축을 따라 나타나는 쌍정을 대부분의 미소결정 성장과정에서 관찰 하였다. r-plane 사파이어 기판 위에서 성장시킨 GaN 미소 결정을 통하여 극성과 GaN의 성장속도 차이를 확인할 수 있었다.