• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2082-2089
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• 2015

Avian beta-defensin 9 (AvBD9) is a small cationic peptide consisting of 41 amino acids that plays a crucial rule in innate immunity and acquired immunity in chickens. Owing to its wide antibacterial spectrum, lack of a residue, and failure to induce bacterial drug resistance, AvBD9 is expected to become a substitute for conventional antibiotics in the livestock and poultry industries. Using the preferred codon of Pichia pastoris, the mature AvBD9 peptide was designed and synthesized, based on the sequence from GenBank. The P. pastoris constitutive expression vector pGHKα was used to construct a pGHKα-AvBD9 recombinant plasmid. Restriction enzyme digestion was performed using SacI and BglII to remove the ampicillin resistance gene, and the plasmid was electrotransformed into P. pastoris GS115. High-expression strains with G418 resistance were screened, and the culture supernatant was analyzed by Tricine-SDS-PAGE and western blot assay to identify target bands of about 6 kDa. A concentrate of the supernatant containing AvBD9 was used for determination of antimicrobial activity. The supernatant concentrate was effective against Escherichia coli, Salmonella paratyphi, Salmonella pullorum, Pseudomonas aeruginosa, Enterococcus faecalis, and Enterobacter cloacae. The fermentation product of P. pastoris carrying the recombinant AvBD9 plasmid was adjusted to 1.0 × 10⁸ CFU/ml and added to the drinking water of white feather broilers at different concentrations. The daily average weight gain and immune organ indices in broilers older than 7 days were significantly improved by the AvBD9 treatment.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.65-65
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• 2011

Single-well carbon nanotubes (SWNT) have been proposed as a promising candidate for various applications owing to their excellent properties. In particular, their fascinating electrical and mechanical properties could provide a new area for the development of advanced engineering materials. A transparent conductive thin film (TCF) has increased for applications such as liquid crystal displays, touch panels, and flexible displays. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. But, a bundle of CNTs has different electrical properties than their individual counterparts. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodum dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate at $100^{\circ}C$. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then treated with ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. Results, we show that 97 ${\Omega}$/> sheet resistance can be achieved with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after ionic doping treatments were discussed.

• 대한미생물학회지
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• 제21권1호
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• pp.17-31
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• 1986

Forty clinical isolates of Serratia marcescens were tested for their susceptibility to 19 antimicrobial drugs and studied on the molecular characteristics of R plasmids. Cefotaxime (Ct) was the most effective drug and only 2 (5%) strains were resistant to this drug. Thirteen to 18% of strains were resistant to cefoperazone (Cz), amikacin (Ak). and trimethoprim (Tp), and 28 to 40% were resistant to piperacillin (Pi), nalidixic acid (Na), gentamicin (Gm), and cefoxitin (Cx). A majority of strains were resistant to carbenicillin (Cb), tobramycin (Tp), kanamycin (Km), and cefamandole (Cd), and all to cephalothin. One half of the isolates were resistant to 10 or more drugs. $MIC_{90}$ of Pi to Gm-resistant strains (Gm') were 8 times higher than that to Gm-susceptible strains (Gm'), but $MIC_{90}$ of Ak, Cx, Ct, and Cz were almost the same between both Gm' and Gm' strains. Nine (23.7%) strains among 38 of multiply drug-resistant S. marcescens transferred conjugally their partial patterns of resistance to E. coli or Klebsiella strains, and two S. marcescens strains producing bacteriocin transferred their resistance to Klebsiella only, but not to E. coli. The plasmid profiles of S. marcescens were studied by the methods of SDS lysis and agarose gel electrophoresis. Twenty-four (60%) strains carried one to four plasmids of 1.4. to 144 Mdal, and conjugative R plasmids of 49 to 127 Mdal were noted in transconjugants. MIC levels of drugs in transconjugants were variable by the R plasmids and recipient strains.

• 공업화학
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• 제10권5호
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• pp.784-788
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• 1999

본 연구에서는 $Na_2SO_4,\;Na_2CO_3,\;SDS$와 $NaClO_4$ 전해질용액에서 피롤단량체를 전기중합한 후, 중합시간과 전해질에 따른 피롤중합막의 점탄성 특성을 QCA를 이용하여 분석하였다. 그리고, 180초간 피롤을 중합하여 피막한 수정진동자를 0.1 M $NaClO_4$ 전해질용액에 넣어서 전위주사하여 각각의 전해질에 대한 폴리피롤박막의 산화환원특성을 분석하였다. 본 실험에서는 수정진동자의 한쪽 전극을 작용전극으로 사용하였으며, 각각의 실험에서 공진주파수, 공진저항, 전류 값을 측정하여 분석하였다. 본 연구 결과, $ClO_4{^{-}}$와 $DS^-,\;SO_4{^{-2}},\;CO_3{^{-2}}$의 순서로 피롤막이 탄성막에서 점차 점탄성막으로 변하여 가면서 중합됨을 알 수 있었다.

• 대한수의학회지
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• 제42권2호
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• pp.253-260
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• 2002

Fowl red mite, Dermanyssus gallinae, is the most important ectoparasite affecting egg layers worldwide. More than 35 compounds have been used for fowl red mite control. Although some of them are efficient, several compounds are unsuitable in terms of food safety and environmental problems. Some compounds are efficient in theory but inadequate in practice. It is also expensive in material and labor to control effectively. Effective doses are very close to toxic doses and repeated treatment is required. Repeated, long term treatment of compounds on fowl red mite populations, may cause heritable resistance against the mites. In this study, antigenicity of fowl red mite and house dust mite, Dermatophagoides pteronyssinus, were identified by SDS-PAGE, silver staining, Western blotting and ELISA to investigate immune effects against fowl red mite using somatic antigens of fowl red mite and house dust mite. By SDS-PAGE, silver staining and Western blotting, several common antigens (110, 60, 56, 49, 46 kDa) of both fowl red mite and house dust mite were recognized. To identify immune effect of somatic antigens of fowl red mite and house dust mite, sixty white leghorn broilers(1 week old) were used. Among sixty white leghorn broilers, twenty were immunized with fowl red mite somatic antigens(Group I), twenty immunized with house dust mite antigens(Group II), and twenty were control group without antigen(Group III), respectively. After immunization, it was identified that antibody titers were increased both in group and II. Then all groups were challenged with fowl red mites. After 2 months, measurements of body weights, packed cell volume(PCV), ELISA OD values and numbers of mites were significant(p<0.05). These results suggest that fowl red mite and house dust mite, which are easy to collect and maintain, can be good vaccine candidates against fowl red mite in chicken.

• Applied Biological Chemistry
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• 제37권4호
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• pp.221-225
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• 1994

농산폐섬유소 자원을 이용하여 세균 단세포단백질(single cell protein)을 생산하기 위한 연구로서 부엽토에서 분리된 Cellulomonas sp. KL-6의 증식에 미치는 열처리 및 항생물질의 효과에 대해 조사하였다. KL-6 균주는 $65^{\circ}C$에서 5분, $75^{\circ}C$에서 1분 및 $85^{\circ}C$에서 15초까지 열처리시에는 증식하였고 그 이상의 온도에서는 처리시간에 관계없이 자라지 못하였다. $48^{\circ}C$에서 10분간의 예비 열처리는 본 균주의 열저항성을 증가시키지 못하였다. 기질 중 casamino acid(1%), yeast extract(1%), xylose(5%)는 KL-6 균주의 열저항성을 증가시켰으나 cysteine(0.03 M), sodium citrate(1%), casein(1%)은 반대로 열저항성을 감소시켰다. KL-6 균주는 $penicillin-G(1.536\;{\mu}g/ml)$와 $ampicillin(3.125\;{\mu}g/ml)$에 감수성인 반면, kanamycin에 대해서는 $200\;{\mu}g/ml$ 이상에서도 강한 내성을 보였다. SDS 처리에 의해 kanamycin의 내성이 제거되었고 제거율은 $9.2{\sim}31.2%$로 각각 나타났다.

• 생명과학회지
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• 제18권6호
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• pp.845-851
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• 2008

Bacillus sp. J105 strain으로부터 유도된 ${\beta}-lactamase$는 ammonium sulfate 침전, 이온 교환 칼럼 크로마토그래피, 겔 여과 등의 과정을 거쳐 SDS-PAGE에서 단일 band로 정제하였다. 정제된 효소의 분자량은 31 kDa이었으며 등전점은 7.35이었다. 효소반응의 최적 pH와 온도는 각각 5와 $40^{\circ}C$이었다. 정제 단백질의 총 아미노산 조성의 분석 결과, Gly과 Ala이 각각 14.1과 13.3 mole%로 가장 많은 아미노산 잔기를 차지하고 있었다. 정제 효소의 ampicillin을 기질로 하였을 때의 Km값은 1.33 mM이었고 Vmax값은 0.36 mM/ml이었다.

• 환경생물
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• 제39권4호
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• pp.445-451
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• 2021

Agrobacterium tumefaciens strain CP4 유래 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) 유전자를 포함하는 유전자변형생물체(Living modified organism, LMO)가 개발되었다. 이 같은 LMO는 국내 승인되어 사료용, 식품용, 가공용으로 이용 중이다. 간이면역 검사키트 개발을 위해서는 고효율의 단클론 항체 개발이 필수적이다. 본 연구에서는 대장균 BL21 (DE3)에서 재조합 CP4 EPSPS 단백질을 정제하였으며 SDS-PAGE와 MALDI-TOF MS 분석으로 단백질 특성을 분석하였다. 단클론 항체 제작은 (주)앱클론의 SOP 매뉴얼에 따라 진행하였다. 본 연구 결과 5개의 단클론 항체 클론(2F2, 4B9, 6C11, 10A9, 10G9)를 확보하였다. 5종의 단클론 항체의 효율과 특이도 검정을 위해서 LM 면화 추출액을 이용한 western blotting 분석을 실시하였다. 모든 단클론 항체는 CP4 EPSPS를 함유하는 MON1445와 MON88913을 특이적으로 검출하였으며 비변형 면화 및 타종의 LM 면화에서는 검출되지 않았다. 이러한 결과들을 바탕으로 CP4 EPSPS 단클론 항체는 LMO에 함유된 CP4 EPSPS 단백질을 타겟으로 항체 기반 검출법 개발에 활용될 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.410-416
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• 2008

The gene SfXyn10, which encodes a protease-resistant xylanase, was isolated using colony PCR screening from a genomic library of a feather-degrading bacterial strain Streptomyces fradiae var. k11. The full-length gene consists of 1,437bp and encodes 479 amino acids, which includes 41 residues of a putative signal peptide at its N terminus. The amino acid sequence shares the highest similarity (80%) to the endo-1,4-${\beta}$-xylanase from Streptomyces coelicolor A3, which belongs to the glycoside hydrolase family 10. The gene fragment encoding the mature xylanase was expressed in Escherichia coli BL21 (DE3). The recombinant protein was purified to homogeneity by acetone precipitation and anion-exchange chromatography, and subsequently characterized. The optimal pH and temperature for the purified recombinant enzyme were 7.8 and $60^{\circ}C$, respectively. The enzyme showed stability over a pH range of 4.0-10.0. The kinetic values on oat spelt xylan and birchwood xylan substrates were also determined. The enzyme activity was enhanced by $Fe^{2+}$ and strongly inhibited by $Hg^{2+}$ and SDS. The enzyme also showed resistance to neutral and alkaline proteases. Therefore, these characteristics suggest that SfXyn10 could be an important candidate for protease-resistant mechanistic research and has potential applications in the food industry, cotton scouring, and improving animal nutrition.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.574-581
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• 2011

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a fullsystem understanding of the radiation stress protection mechanisms of bacteria in different environments.