• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.281-286
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• 2001

Since the number of amino groups which are exposed by deacetylation of acetyl-D-glucosamine influences antimicrobial activity, a chitosan oligosaccharide (COS) derivative by N-conjugation of COS with asparagine, an amino acid with two amino groups, was synthesized and the antimicrobial effect on E. coli growth was compared with other COS derivatives which were N-conjugated with glycine, alanine, aspartic acid, cysteins, an methionine, and unmodified COS. The structure of asparagine N-conjugated COS (Asn-COS) derivative was identified by using a FT-IR, $^{13}C\;FT-NMR$, and an elemental analyzer. The antimicrobial activity of Asn-COS against E. coli growth was significantly improved as compared to the other COS derivatives as well as COS itself. This means that Asn-COS with two positive charges strongly interacts with the carboxyl negative charges on the bacteria cell wall. The results for Asn-COS were as follows: 100% bactericidal activity, 0.002% MIC, and no growth of E. coli during 3 days of culture time, suggesting that Asn-COS may be useful as a new antibiotic agent.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1984-1989
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• 2006

Deacetylated chitosan oligosaccharide (COS) had effective antiprotozoal activity against Trichomonas vaginalis (Minimal Inhibitory Concentration, MIC 0.25%), whereas 80% acetylated cas showed no antiprotozoal activity (MIC > 1 %). an the other hand, 80% acetylated cas showed growth stimulatory activity against the protozoa. When T. vaginalis was treated with 98% deacetylated COS at 0.25% concentration, the viability of the protozoa was rapidly decreased within 15 min, and the protozoa completely died within 40 min. Ultrastructural changes of trichomonads treated with COS included a loss of defined nuclear membrane and endoplasmic reticulum membranes, an increase in the number of free ribosome, vacuolation, and ultimately lysis of the cell membrane. These results indicate that deacetylated COS can be used as an antitrichomonal agent, although its lethal mechanism is not known.

• 한국식품조리과학회지
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• 제18권6호
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• pp.586-592
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• 2002

The purpose of this study was to investigate the quality characteristics of Jeung-Pyhn by the addition of chitosan-oligosaccharide (COS, Chitoligo-L). Jeung-Pyun is a traditional Korean fermented rice cake leavened by yeast. To develop a functional Jeung-Pyun, COS was added to the rice at the levels of 0, 2, 4 and 6% of the 2-hour-soaked rice. Physicochemical, sensory, rheological and inner structure characteristics of Jeung-Pyun were examined. The pH values of COS Jeung-Pyun batters were decreased with fermentation time. In sensory evaluation, the uniformity of the grain and overall quality of Jeung-Pyun added with 2% COS had the highest score among the samples. In He rheological properties measured with rheometer, the hardness of Jeung-Pyun with COS was higher than control. Cohesiveness of Jeung-Pyun added with 4% COS and gumminess, brittleness and springiness of Jeung-Pyun added with 2% COS were the highest among the samples. The inner structure observed by scanning electron microscope showed that Jeung-Pyun added with 2% COS had the largest and the most uniform air cells. In conclusion, Jeung-Pyun with 2% COS had positive effects on the qualify of Jeung-Pyun.

• Journal of Microbiology and Biotechnology
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• 제17권9호
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• pp.1546-1549
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• 2007

Chitosan oligosaccharide (COS, 3 kDa

• Macromolecular Research
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• 제12권6호
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• pp.573-580
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• 2004

To prepare chitosan-based polymeric amphiphiles that can form nanosized core-shell structures (nanopar­ticles) in aqueous milieu, chitosan oligosaccharides (COSs) were modified chemically with hydrophobic cholesterol groups. The physicochemical properties of the hydrophobized COSs (COSCs) were investigated by using dynamic light scattering and fluorescence spectroscopy. The feasibility of applying the COSCs to biomedical applications was investigated by introducing them into a gene delivery system. The COSCs formed nanosized self-aggregates in aqueous environments. Furthermore, the physicochemical properties of the COSC nanoparticles were closely related to the molecular weights of the COSs and the number of hydrophobic groups per COS chain. The critical aggregation concentration values decreased upon increasing the hydrophobicity of the COSCs. The COSCs effi­ciently condensed plasmid DNA into nanosized ion-complexes, in contrast to the effect of the unmodified COSs. An investigation of gene condensation, performed using a gel retardation assay, revealed that $COS6(M_n=6,040 Da)$ containing $5\%$ of cholesteryl chloroformate (COS6C5) formed a stable DNA complex at a COS6C5/DNA weight ratio of 2. In contrast, COS6, the unmodified COS, failed to form a stable COS/DNA complex even at an elevated weight ratio of 8. Furthermore, the COS6C5/DNA complex enhanced the in vitro transfection efficiency on Human embryonic kidney 293 cells by over 100 and 3 times those of COS6 and poly(L-lysine), respectively. Therefore, hydrophobized chitosan oligosaccharide can be considered as an efficient gene carrier for gene delivery systems.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.2042-2045
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• 2007

The effect of chitosan oligosaccharide (COS, 1 kDa${\gamma}$, 10 ng/ml IL-$1{\alpha}$, and 25 ng/ml TNF-${\alpha}$) in HT-29 cells. Inducible nitric oxide synthase (iNOS) expression induced by these cytokines was inhibited by COS. COS pretreatment inhibited the invasiveness of cytokines-treated HT-29 cells through Matrigel-coated membrane in a dose-dependent manner. COS also inhibited cytokines-induced matrix metalloproteinase (MMP)-2 activity. This study shows that proinflammatory cytokines induce NO production, iNOS expression, and invasiveness of human colorectal adenocarcinoma HT-29 cells. COS pretreatment inhibited cytokines-mediated NO production, iNOS expression, and invasiveness of HT-29 cells. These results provide sufficient information for the further development of COS as an antitumor metastatic agent for the treatment of colon cancer.

• 동아시아식생활학회지
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• 제13권2호
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• pp.122-129
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• 2003

This study was carried out in order to investigate the dextran formation and the internal structure of the chitosan-oligisaccharide(COS) Jeung-Pyun during the fermentation. To develop a functional Jeung-Pyun, COS was added to the rice at the level of 0, 2, 4, and 6% to the 2-hour-soaked rice. The pH, dextran and reducing sugar contents of COS batter, specific volume and the internal structure of COS were analyzed as a function of fermentation time. The specific volume of COS peaked at the 3 hour fermentation. The pH values of COS batters reduced with the fermentation time. The dextran content of the control batters peaked at the 7 hour fermentation. In contrast, the dextran contents of COS batters reduced up to 7th hour of fermentation, and then increased slowly until 20th hour of the fermentation process. From the air pore size and distribution of COS observed by SEM, the COS fermented fur 3 hour was judged as the best. It was concluded that COS prevented the fermation of dextran at the early stage of fermentation process.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.503-507
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• 2002

Chitosan oligosaccharides (COSs) were prepared and fractionated into three groups of COS [a high molecular weight COS (HMWCOS), medium molecular weight COS (LMWCOS), and low molecular weight COS (LMWCOS)] according to their molecular weight, using an ultrafiltration membrane enzymatic bioreactor designed earlier [8]. Antitumor activity of these COSs was then examined against Sarcoma 180 solid (S180) or Uterine cervix carcinoma No. 14 (Ul4) tumor cell-bearing mice. Among these COSs, MMWCOS with molecular weight range from 1.5 to 5.5 kDa effectively inhibited the growth of both tumor cells in the mice. In addition, the administration of MMWCOS resulted in increased thymus weight among lymphoid organs. The mice treated with MMWCOS showed improved survival rate and larger number of survivors after 40 days of feeding. The most effective of MMWCOS far antitumor activity in the S180- or U14-bearing mice was 20 mg/kg/day or more.

• 한국식품영양과학회지
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• 제34권1호
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• pp.36-41
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• 2005

본 연구는 고콜레스테롤을 급여한 흰쥐 에 키토산 올리고당의 첨가 수준을 달리한 식이가 흰쥐의 지방대사에 미치는 영향을 알아보고자 수행하였다. 체중이 174.7$\pm$6.3 g인 Sprague-Dawley종 수컷 흰쥐에게 고콜레스테롤혈증을 유발시키기 위하여 콜레스테롤을 식 이 무게의 0.5%를 급여하고 키토산 올리고당을 식이 무게의 1.0%와 2.0%로 하여 총 3군으로 나누어 4주간 사육하였다. 식이섭취량과 체중증가량은 식이에 의한 영향이 없었다. 혈청 중 총 콜레스테롤, 중성지방은 대조군에 비해 2.0% 키 토산 올리고당을 첨가한 군에서 유의적으로 그 농도가 크게 감소하였으며 HDL-콜레스테롤/총콜레스테롤 비는 키토산 올리고당 첨가에 의해 높아지는 경향을 보였다. 간 조직 중 TBARS 함량은 키토산 올리고당을 첨가하였을 경우 유의적으로 낮게 나타났으며 SOD와 catalase의 활성은 키토산 올리고당을 첨가한 군이 대조군에 비해 유의적으로 낮았다. 이상의 결과를 볼 때 키토산 올리고당은 체내 지방대사에 있어 총콜레스테롤과 LDL-콜레스테롤, 중성지방 및 TBARS 함량을 낮추고 HDL-콜레스테롤/총 콜레스테롤 비는 높이는 효과를 나타냈으며, 또한 생체내 고콜레스테롤에 의한 산화적 스트레스로부터 간을 보호하는 것을 알 수 있었다.

• 폴리머
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• 제32권3호
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• pp.263-269
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• 2008

키토산에 기초한 소수성 항암제의 전달체를 개발하기 위하여, 젖산염 키토산을 소수성기로써 담즙산 중의 하나인 리소콜릭산(lithocholic acid, LA)을 이용하여 화학적으로 개질하였다. LA가 결합된 키토산 나노입자(COS-LA)의 물리화학적 특성을 $^1H$-NMR, dynamic light scattering(DLS) 그리고 spectrofluorophotometer를 이용하여 조사하였다. 항암제로써 파클리탁셀(paclitaxel)이 봉입된 CLs-Tx(COS-LA-paclitaxel) 나노입자는 투석 방법을 이용하여 제조되었고 HPLC를 통하여 약물의 봉입량을 측정하였다. DLS를 이용하여 측정한 파클리탁셀이 봉입된 나노입자의 크기는 약 300 nm를 나타내었다. 또한 임계미셀형성(CMC) 농도는 LA의 치환도에 의존한다는 것을 확인하였다. 이상의 결과로부터 본 연구에서 제조한 LA가 결합된 젖산염 키토산이 파클리탁셀 전달체로서 매우 높은 응용 가능성을 나타내고 있음을 확인하였다.