• Biomolecules & Therapeutics
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• 제10권3호
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• pp.156-164
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• 2002

In the present study, we tried to investigate whether polymerized basic amino acid e.g. poly-L-lysine (PLL) which has the degree of polymerization under 50mer significantly affects the physiological and stimulated mucin release from cultured hamster tracheal surface epithelial cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with $^3{H}$-glucosamine for 24 hr and chased for 30 min in the presence of either PLLs or adenosine triphosphate (ATP) and PLL to assess the effects on basic or ATP-stimulated $^3{H}$-mucin release. Possible cytotoxicities of PLLs were assessed by measuring lactate dehydrogenase (LDH) release from HTSE cel1s during treatment. The results were as follows: PLLs significantly inhibited basic mucin release from cultured HTSE cells in a dose-dependent manner from the range of 46mer to 14mer; PLL 46mer significantly inhibited the stimulated mucin release by ATP from cultured HTSE cells; there was no significant release of LDH from cultured HTSE cells during treatment. We conclude that PLLs inhibit both physiological and stimulated mucin release from airway epithelial cells without significant cytotoxicity and PLL lost its activity under the range of 14mer. This finding suggests that polymer of basic amino acid like PLL might function as a regulator for hypersecretion of mucus manifested in various respiratory diseases.

• Asian-Australasian Journal of Animal Sciences
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• 제32권12호
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• pp.1942-1949
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• 2019

Objective: Leukocyte cell-derived chemotaxin 2 (LECT2) is associated with several physiological processes including inflammation, tumorigenesis, and natural killer T cell generation. Chicken LECT2 (chLECT2) gene was originally identified as one of the differentially expressed genes in chicken kidney tissue, where the chickens were fed with different calcium doses. In this study, the molecular characteristics and gene expression of chLECT2 were analyzed under the stimulation of toll-like receptor 3 (TLR3) ligand to understand the involvement of chLECT2 expression in chicken metabolic disorders. Methods: Amino acid sequence of LECT2 proteins from various species including fowl, fish, and mammal were retrieved from the Ensembl database and subjected to Insilco analyses. In addition, the time- and dose-dependent expression of chLECT2 was examined in DF-1 cells which were stimulated with polyinosinic:polycytidylic acid (poly [I:C]), a TLR3 ligand. Further, to explore the transcription factors required for the transcription of chLECT2, DF-1 cells were treated with poly (I:C) in the presence or absence of the nuclear factor ${\kappa}B$ ($NF{\kappa}B$) and activated protein 1 (AP-1) inhibitors. Results: The amino acid sequence prediction of chLECT2 protein revealed that along with duck LECT2 (duLECT2), it has unique signal peptide different from other vertebrate orthologs, and only chLECT2 and duLECT2 have an additional 157 and 161 amino acids on their carboxyl terminus, respectively. Phylogenetic analysis suggested that chLECT2 is evolved from a common ancestor along with the actinopterygii hence, more closely related than to the mammals. Our quantitative polymerase chain reaction results showed that, the expression of chLECT2 was up-regulated significantly in DF-1 cells under the stimulation of poly (I:C) (p<0.05). However, in the presence of $NF{\kappa}B$ or AP-1 inhibitors, the expression of chLECT2 is suppressed suggesting that both $NF{\kappa}B$ and AP-1 transcription factors are required for the induction of chLECT2 expression. Conclusion: The present results suggest that chLECT2 gene might be a target gene of TLR3 signaling. For the future, the expression pattern or molecular mechanism of chLECT2 under stimulation of other innate immune receptors shall be studied. The protein function of chLECT2 will be more clearly understood if further investigation about the mechanism of LECT2 in TLR pathways is conducted.

• Advances in nano research
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• 제14권2호
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• pp.201-210
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• 2023

A ZnO/poly (amide-imide) hybrid nanocomposite film with different weight percentages of Zinc oxide (ZnO) nanoparticles is synthesized and characterized in this paper. A two-step reaction successfully synthesized a new kind of heteroaromatic diamine with bulky pendant groups. In order to produce 3, 5-dinitro-3, 3-bis (4-(4-Nitrophenoxy) phenyl) -2- benzofuran-1-one, 3, 3'-bis (4-hydroxyphenyl) benzofuran-1-one and 3'-bis (4-hydroxyphenyl) benzofuran-1-one were combined with 3'-bis (3-hydroxyphenyl) benzofuran-1-one. The obtained dinitro was then reduced by zinc dust and hydrochloric acid. The reaction of 4, 4^* carbonyl diphthalic anhydride with amino acid L-alanine in acetic acid leads to the production of very high yields of chiral diacid monomer. As a result of the direct polymerization of these monomers, new optically active polymers were formed (amide-imide). In order to synthesize poly (amide-imide)/ZnO nanocomposites with different weight percentages (2, 4, 6, 8, and 10%), PAI and ZnO nanoparticles were combined using ultrasonication SEM, Fourier transform infrared spectroscopy, X-ray diffraction and thermal gravimetry were used to characterize the PAI films.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.205-211
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• 2005

Water-soluble polyethyleneimine (PE) derivatives containing nucleic acid bases and hydrophilic amino acids such as homoserine (Hse) and serine were prepared by the activated ester method as nucleic acid models. From spectroscopic measurements, the polymers were found to interact with DNA accompanied by an induction of conformational change. Hypochromicity in UV spectra indicated that a stable polymer complex was formed between poly (A) with PEI­Hse-Ura by complementary hydrogen bonding with equimolar nucleic base units (adenine:uracil=1:1). The induced conformation of DNA by the interaction with the polymer containing uracil and homoserine (PEI-Hse-Ura) was concluded to be a super triple helical structure. The formation of the polymer complex, DNA: PEI-Hse-Ura, was found to be affected by the presence of metal ions such as $Ca^{2+}\;and\;Cu^{2+}$.

• Natural Product Sciences
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• 제24권4호
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• pp.293-297
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• 2018

Sasa quelpaertensis Nakai leaves contain a mixture of polysaccharides, amino acids, and polyphenols, which mediate various biological activities. For efficient utilization of its leaf, we reported the preparation procedure for phytochemical-rich extract (PRE) using the leaf residue, which was by-product of hot water extraction. This study was undertaken to evaluate the effects of PRE and its major constituent, p-coumaric acid,on the growth of several human cancer cell lines (MKN-74, MKN-45, SNU-1, SNU-16, and HL-60). The ethyl acetate fraction of PRE and p-coumaric acid significantly inhibited the proliferation of MKN-74 and HL-60 cells, respectively, and induced cell apoptosis, down-regulated Bcl-2 and poly (ADP-ribose) polymerase levels, and up-regulated those of Bax and caspase-3. These results show the potential utility of S. quelpaertensis Nakai leaves in cancer prevention.

• Macromolecular Research
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• 제13권5호
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• pp.373-384
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• 2005

Novel pH-sensitive moieties containing an s-triazine ring were synthesized with sulfonamide and secondary amino groups. The synthesized pH-sensitive moieties were used for the synthesis of a pH-sensitive amphiphilic ABA triblock copolymer. The pH-sensitive triblock copolymer was composed of diblock copolymers, methoxy poly(ethylene glycol)-poly ($\varepsilon$-caprolactone-co-D,L-lactide) (MPEG-PCLA), and pH-sensitive moiety. These copolymers could be dissolved molecularly in both acidic and basic aqueous media at room temperature due to secondary amino and sulfonamide groups. The synthesized s-triazine rings containing pH-sensitive compounds were characterized by ${^1}H-NMR,\;{^13}C-NMR$, and LC/MSD spectral data. The synthesized diblock and triblock copolymers were also characterized by ${^1}H-NMR$ and GPC analyses. The critical micelle concentrations at various pH conditions were determined by fluorescence technique using pyrene as a probe. Furthermore, the micellization and demicellization study of the triblock copolymer was done with pH-sensitive groups. The sensitivity towards pH change was further established by acid-base titration.

• Journal of Applied Biological Chemistry
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• 제54권1호
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• pp.1-6
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• 2011

Poly-${\gamma}$-glutamic acid (${\gamma}$-PGA)는 청국장이 발효할 때 생성되는 점질성 물질의 하나로, monomer glutamic acid의 ${\alpha}$-아미노기와 ${\gamma}$-카르복실기 사이의 amide linkage에 의해 결합된 D(-)와 L(-) glutamic acid repeat units로 이루어진 homopolymer이다. 주로 Bacillus sp.에 의해 생산된다. ${\gamma}$-PGA는 수용성, 음이온성, 무독성, 생분해성, 생체적 합성, 식용 등의 다양한 특성을 가지고 있기 때문에 여러 분야에서 응용되고 있다. 본 실험에서 ${\gamma}$-PGA를 생산하는 균주를 우리나라의 전통발효식품인 청국장으로부터 분리하였다. 분리균주의 형태 및 배양학적, 생리학적 특성, API kit 및 16S rRNA 서열을 사용하여 동정한 결과, 분리균주 GS-2는 B. subtilis와 가장 유사하여 B. subtilis GS-2로 명명하였다. 분리 정제된 ${\gamma}$-PGA의 동정은 TLC, HPLC, FTIR 그리고 $^1H$-NMR spectroscopy를 통하여 확인하였다.

• 대한화학회지
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• 제37권4호
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• pp.378-389
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• 1993

합성 polypeptide인 poly(γ-benzyl-L-glutamate)[PBLG]를 A-segment로 하고, polyoxypropylene(POP)를 B-segment로 하는 AB 형태 블록공중합체와 polypropyleneglycol을 B-segment로 하는 ABA 형태 블록공중합체를 합성한 후, 이들 공중합체의 생식 호르몬인 progesterone, estrone, estradiol, testosterone의 고분자 매트릭스를 제조하여 이들 스테로이드의 방출량의 변화를 연구하였다. PBLG-POP1와 PBLG-POP2의 매트릭스에서의 progesterone, estradiol 및 testosterone 방출속도와 ABA 형태의 GPG1 공중합체에서의 progesterone, estrone 및 testosterone 방출속도가 염기성용액보다 산성용액에서 더 빠름을 보았다. 한편 PBLG-POP1와 PBLG-POP2의 매트릭스에서의 estrone 그리고 ABA 형태의 GPG1의 매트릭스에서의 estradiol의 방출속도는 산성용액에서 보다 중성 및 염기성용액에서 더 빨랐다. 서로 다른 매트릭스에서의 방출차이는 GPG1 > PBLG-POP1 > PBLG-POP2이며, 방출속도는 스테로이드의 분자량에 반비례함을 보였다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.259-259
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• 2006

PAU is the block copolymer consists of a small amount of a small amount of poly(${\gamma}-methyl-L-glutamate$) (PMLG) and the polyurethane. The urethane segments are hydrophobic and then strongly interact with the other hydrophobic materials such as PTFE, and the PMLG segments with the ${\alpha}-helix$ structure possess the cytocompatibility. Therefore, PAU can be easily coated onto the PTFE fiber and acts as an artificial extracellular matrix with the high cytocompatibility Results shows, the immobilization, cultured and functions of porcine hepatocytes is greatly improved.

• Elastomers and Composites
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• 제50권3호
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• pp.175-183
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• 2015

A series of fluorinated aromatic poly(hydroxyamide)s (PHAs) were synthesized by direct polycondensation of diacides containing 2,6-dimethylphenoxy group and quinoxaline ring in the main chain with 2,2-bis-(3-amino-4-hydroxyphenyl) hexafluoropropane. The PHAs had relatively low inherent viscosities in the range of 0.35~0.43 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs exhibited excellent solubility in aprotic solvents such as NMP, DMAc, DMF and DMSO as well as in common organic solvents such as pyridine, THF, and m-cresol at room temperature. However, the poly(benzoxazole)s (PBOs) were quite insoluble in all organic solvents except partially soluble in concentrated sulfuric acid. The PBOs showed glass transition temperatures between 233 and $284^{\circ}C$ by DSC and maximum weight loss temperatures in the range of $536-546^{\circ}C$ by TGA.