• Bulletin of the Korean Chemical Society
• /
• 제29권9호
• /
• pp.1803-1806
• /
• 2008

• Journal of Microbiology and Biotechnology
• /
• 제16권11호
• /
• pp.1713-1719
• /
• 2006

A method for the simple, rapid, specific, and accurate detection of Bacillus anthracis spores was developed by employing specific capture peptides conjugated with fluorescent quantum dots (QDs). It was possible to distinguish B. anthracis spores from the spores of B. thuringiensis and B. cereus using these peptide-QD conjugates by flow cytometric and confocal laser scanning microscopic analyses. For more convenient high-throughput detection of B. anthracis spores, spectrofluorometric analysis of spore-peptide-QD conjugates was performed. B. anthracis spores could be detected in less than 1 h using this method. In order to avoid any minor yet false-positive signal caused by the presence of B. thuringiensis spores, the B-Negative peptide, which can only bind to B. thuringiensis, conjugated with another type of QD that fluoresces at different wavelength was also developed. In the presence of mixed B. anthracis and B. thuringiensis spores, the BABA peptide conjugated with QD525 and the B-Negative peptide conjugated with QD585 were able to bind to the former and the latter, specifically and respectively, thus allowing the clear detection of B. anthracis spores against B. thuringiensis spores by using two QD-labeling systems. This capture peptide-conjugated QD system should be useful for the detection of B. anthracis spores.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제11권3호
• /
• pp.262-267
• /
• 2006

The objective of this study was to develop new self-organized nanogels as a means of drug delivery in patients with cancer. Pullulan (PUL) and deoxycholic acid (DOCA) were conjugated through an ester linkage between the hydroxyl group in PUL and the carboxyl group in DOCA. Three types of PUL/DOCA conjugates were obtained, differing in the number of DOCA substitutions (DS; 5, 8, or 11) per 100 PUL anhydroglucose units. The physicochemical properties of the resulting nanogels were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of DS 11 was the smallest (approx. 100 nm), and the size distribution was unimodal. To determine the organizing behavior of these conjugates, we calculated their critical aggregation concentrations (CACs) in a 0.01-M phosphate buffered saline solution. They were $10.5{\times}10^{-4}mg/mL,\;7.2{\times}10^{-4} mg/mL,\;and\;5.6{\times}10^{-4} mg/mL$ for DS 5, 8, and 11, respectively. This indicates that DOCA can serve as a hydrophobic moiety to create self-organized nanogels. To monitor the drug-releasing behavior of these nanogels, we loaded doxorubicin (DOX) onto the conjugates. The DOX-loading efficiency increased with the degree of DOCA substitution. The release rates of DOX from PUL/DOCA nanogels varied inversely with the DS. We concluded that the PUL/DOCA nanogel has some potential for use as an anticancer drug carrier because of its low CAC and satisfactory drug-loading capacity.

• Journal of Microbiology and Biotechnology
• /
• 제16권9호
• /
• pp.1369-1376
• /
• 2006

Self-organized nanogels were prepared from pullulan/biotin conjugates (PU/Bio) for the development of an effective anticancer drug delivery system. The degree of biotin substitution was 11, 19, and 24 biotin groups per 100 anhydroglucose units of pullulan. The physicochemical properties of the nanogels (PU/Bio1, 2 and 3) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all the samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CACs) of the nanoparticles in distilled water were $2.8{\times}10^{-2},\;1.6{\times}10^{-2}$, and $0.7{\times}10^{-2}mg/ml$ for the PU/Bio1, 2, and 3, respectively. The aggregation behavior of the nanogels indicated that biotin can perform as a hydrophobic moiety. To observe the specific interaction with a hepatic carcinoma cell line (HepG2), the conjugates were labeled with rhodamine B isothiocyanate (RITC) and their intensities measured using a fluorescence microplate reader. The HepG2 cells treated with the fluorescence-labeled PU/Bio nanoparticles were strongly luminated compared with the control (pullulan). Confocal laser microscopy also confirmed internalization of the PU/Bio nanogels into the cancer cells. Such results demonstrated that the biotin in the conjugate acted as both a hydrophobic moiety for self-assembly and a tumor-targeting moiety for specific interaction with tumor cells. Consequently, PU/Bio nanogels would appear to be a useful drug carrier for the treatment of liver cancer.

• Macromolecular Research
• /
• 제16권6호
• /
• pp.510-516
• /
• 2008

New antitumor active polymers, poly(methacryloyl-2-oxy-1,2,3-propanetricarboxylic acid-co-exo-3,6-epoxy-l,2,3,6-tetrahydrophthalic acid) [poly(MTCA-co-ETAc)], poly(methacryloyl-2-oxy-l,2,3-propanetricarboxylic acid-co-hydrogen ethyl-exo-3,6-epoxy-l,2,3,6-tetrahydrophthalate) [poly(MTCA-co-HEET)], and poly(methacryloyl-2-oxy-l,2,3-propanetricarboxylic acid-co-a-ethoxy-exo-3,6-epoxy-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil) [poly(MTCA-co-EETFU)] were synthesized and characterized. Their antitumor activity, inhibition of DNA replication and antiangiogenesis were examined. The structures of the polymers were identified by FT-IR, $^1H$ and $^{13}C$-NMR spectroscopy. The number average molecular weights of the fractionated polymers determined by GPC ranged from 9,400 to 14,900, and polydispersity indices were less than 1.7. The in vitro cytotoxicity of these polymers was determined and their antitumor activity was evaluated. The $IC_{50}$ values (the drug concentration at inhibition of 50% tumor growth) indicated that the synthesized polymers were much better inhibitors of cancer cells and showed lower cytotoxicity than the free 5-FU. The in vivo antitumor activity of the conjugates was examined using mice bearing the sarcoma 180 tumor cell line. The life spans (TIC) of the mice treated with the conjugates were higher than those treated with the free 5-FU. In addition, the synthesized conjugates showed excellent antiangiogenic activity based on an embryo chorioallantoic membrane assay.

• KSBB Journal
• /
• 제14권1호
• /
• pp.82-90
• /
• 1999

병원성 미생물을 측정할 수 있는 분석시스템을 구성하기 위해 면역학적 성분들을 합성하였고, 이를 이용하여 모델 시스템을 구성함으로써 균 세포 분석원리가 연구되었다. 구성성분을 준비하기 위해 Salmonella thompson에 대한 복합 클론항체를 면역 친화 크로마토그래피를 이용하여 정제하였고, 이렇게 정제된 항체를 Streptavidin과 horseradush peroxdase에 화학결합시켰다. 항체와 Streptavidinfdm은 각각 SMCC와 SPDP에 의해 활성화 되있고 두 물질을 반응시킴으로써 중합체가 합성되었다. 중합체는diaminobiotion 젤과 sephades G-100젤을 이중 층으로 쌓은 칼럼을 이용하여 정제되었다. 항체- HRP 중합체의 합성을 위해, HRP를 $NAIO_4$ 처리에 의해 안정화된 중합체는 Biohel A5M을 이용한size exchusion크로토그래피로 정제되었다. 이렇게 준비된 중합체들과 dot-bloner 그리고 biotim이 고정화된 nitrocellulose membrane($12\mum$ pore size)을 이용하여 모델시스템을 구성하였다. 분석물질(S.Thormpson cells)을 먼적 액상에서 두 중합체와 반응되었고 반응먹을 membrane이 정착된 blotter에 옮긴 후 하부에 진공을 걸어 면역복합체를 biotin-streptavidin 반응에 의해 membrane 표면에 포획하였다.최적조건 하에서 시스템의 균 세포 분석원리를 확인하였으며 측정하한농도는 약 $1{\mu}g/m{\ell}(10^5 {\cdot} 10^6\;cells/m{\ell}$인 것으로 나타났다. 이러한 측정성능의 주요조절인자는 두항체 종합체 농도의 증가는 항원-항체 응집반응을 초래하는 것으로 나타났다.

• 한국식품과학회지
• /
• 제31권1호
• /
• pp.189-195
• /
• 1999

두유에 존재하는 이소플라본은 주로 포도당 잔기가 aglycone인 genistein과 daidzein에 ${\beta}-glycoside$ 결합을 하고 있는 배당체인 genistin과 daidzin이다. 두유에 설탕을 첨가하여 유산균으로 대두 요구르트로 발효를 시키면 젖산의 생성은 매우 낮아 약 $0.16{\sim}0.29%$에 불과하였지만 대부분의 이소플라본 배당체가 가수분해되어 aglycone으로 전환되었다. 포도당이나 젖당을 첨가하여 발효시키면 정상적인 젖산발효는 일어났지만 이소플라본 배당체의 가수분해는 균주에 따라 변하였다. Lactobacillus delbrueckii subsp. delbrueckii KCTC 1047은 당의 첨가와 무관하게 이소플라본 배당체를 완전히 가수분해시켰다. 그 밖의 균주는 daidzin은 약 $25{\sim}40%$, genistin은 약 $65{\sim}80%$ 정도만을 가수분해시켜 이들 당에 의해 가수분해가 감소하였다. 즉 Lactobacillus delbrueckii subsp. delbrueckii KCTC 1047을 제외한 Lactobacillus bulgaricus KCTC 3188, Lactobacillus casei KCTC 3109, Lactobacillus delbrueckii subsp lactis KCTC 1058, Lactobacillus lactis KCTC 2181과 같은 균주의 경우 이소플라본 배당체의 가수분해에 관여하는 효소인 ${\beta}-glucosidase$가 유도 효소로 포도당이나 젖당에 의해 생산이 저해되었을 것으로 예상된다. 또한 MRS 배지에서 배양하였을 때에도 Lactobacillus delbrueckii subsp. delbrueckii KCTC 1047만이 이 효소를 생산하였다.

• Journal of Ginseng Research
• /
• 제46권3호
• /
• pp.348-356
• /
• 2022

Background: Gintonin is a ginseng-derived exogenous G-protein-coupled lysophosphatidic acid (LPA) receptor ligand. Gintonin exerts its neuronal and non-neuronal in vitro and in vivo effects through LPA receptor subtypes. However, it is unknown whether gintonin can bind to the plasma membrane of cells and can transactivate the epidermal growth factor (EGF) receptor. In the present study, we examined whether gintonin-biotin conjugates directly bound to LPA receptors and transactivated the EGF receptor. Methods: We designed gintonin-biotin conjugates through gintonin biotinylation and examined whether gintonin-biotin conjugate binding sites co-localized with the LPA receptor subtype binding sites. We further examined whether gintonin-biotin transactivated the EGF receptor via LPA receptor regulation via phosphor-EGF and cell migration assays. Results: Gintonin-biotin conjugates elicit [Ca²⁺]_i transient similar to that observed with unbiotinylated gintonin in cultured PC3 cells, suggesting that biotinylation does not affect physiological activity of gintonin. We proved that gintonin-biotin conjugate binding sites co-localized with the LPA1/6 receptor binding sites. Gintonin-biotin binding to the LPA1 receptor transactivates the epidermal growth factor (EGF) receptor through phosphorylation, while the LPA1/3 receptor antagonist, Ki16425, blocked phosphorylation of the EGF receptor. Additionally, an EGF receptor inhibitor AG1478 blocked gintonin-biotin conjugate-mediated cell migration. Conclusions: We observed the binding between ginseng-derived gintonin and the plasma membrane target proteins corresponding to the LPA1/6 receptor subtypes. Moreover, gintonin transactivated EGF receptors via LPA receptor regulation. Our results suggest that gintonin directly binds to the LPA receptor subtypes and transactivates the EGF receptor. It may explain the molecular basis of ginseng physiology/pharmacology in biological systems.

• Archives of Pharmacal Research
• /
• 제23권6호
• /
• pp.585-588
• /
• 2000

4-Bromoacetophenone-pyrrolecarboxarmide conjugates were designed and synthesized as photoinducible DNA cleaving agents which can generate monophenyl radicals capable of causing the hydrogen atom abstraction which initiates the scission of DNA.

• Bulletin of the Korean Chemical Society
• /
• 제27권10호
• /
• pp.1664-1666
• /
• 2006