• 한국동물위생학회지
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• 제41권2호
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• pp.105-110
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• 2018

A total of 41 Salmonella (S.) strains were isolated from pigs suffered with severe watery diarrhea and were tried to identify by both matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction (PCR) analysis. Fibrinous exudate and ulceration in the large intestine were prevalent in gross observation, and variable degrees of enteritis were observed in the histology of large intestines. Subsequent polymerase chain reaction (PCR) analyses demonstrated that 41 strains were identified as S. Typhimurium (39 strains), though 2 stains were failed to identify. Further identification was performed using both direct smear and protein extraction method by MALDI-TOF MS analyses. In terms of extraction methods, 100% (41/41) of isolates were identified to species level of S. spp. Whereas only 43.9% (18/41) were identified to species level using the direct method. These results thus suggest that rapid and accurate diagnosis of porcine salmonellosis can be guaranteed by MALDI-TOF MS combined with protein extraction method.

• 생명과학회지
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• 제15권3호
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• pp.427-433
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• 2005

초파리는 유전학, 발달 생물학, 행동 유전학, 노화 연구에 이르기까지 수많은 연구에 이용 되어져 왔다. 최근 초파리 전체 유전자의 염기서열이 보고되었으며, 유전자의 기능 분석과 발현 단백질에 대한 연구가 진행되고 있다. 본 연구에서는 야생형 초파리에서 추출한 단백질을 이차원 전기영동을 통해 400여개 이상의 단백질 스폿으로 분리하였으며, 각 스폿을 적출하여 트립신으로 처리하여 얻어진 펩타이드 단편을 MALDI-TOF-MS를 이용한 펩타이드 지문 검색으로 질량을 측정하였다. 측정된 질량을 초파리 데이터 베이스를 이용하여 분리한 단백질을 동정함으로써 59개의 유전자에서 발현되는 65개의 단백질 스폿을 동정하였다. 이러한 결과는 향후의 발생단계, 외부 자극, 노화 등에 관련되는 특이적 단백질 연구의 기초 자료로 활용될 수 있을 것이다.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2354-2358
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• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.

• 대한의생명과학회지
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• 제24권2호
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• pp.108-115
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• 2018

In the present study, results of the identification of Gram-positive bacilli (GPB) were analyzed by using the MALDI-TOF MS technique to score each 2-year blood culture at a university hospital. In addition, 16S rRNA sequence analyses and MALDI-TOF MS results are compared to targeting strains that had been isolated two or more times within the same patient, to evaluate the usefulness of MALDI-TOF MS in GPB identification. According to the cut-off (${\geq}1.7$) criteria, there were 410 (57.5%) reliable strains and 303 (42.5%) non-identified strains among the GPB identification results of 713 strains, using a microflex MALDI Biotyper (Bruker Daltonik GmbH, Bremen, Germany). The isolation appeared most often in the following order: Corynebacterium striatum, Bacillus cereus, Bacillus subtilis, Paenibacillus urinalis, and Listeria monocytogenes. Nearly three-fourths, 66 out of 89 (74.2%) of the strains for Corynebacterium striatum; 44 out of 60 (73.3%) strains for Bacillus cereus; and all (25 out of 25, 100%) Listeria monocytogenes strains were identified by their high scores of 2.0 or higher. Most (293 strains out of 303) non-identified strains were strains isolated only once and not significant as infectious bacilli. A total of 43 out of 50 (86.0%) strains matched and were able to be identified based on the 16 rRNA sequencing comparison results of strains that were isolated twice or more within the same patient and significant as infection bacilli. Non-matching among 5 out of 7 strains was not identified, even with MALDI-TOF MS. In conclusion, GPB can be identified in blood cultures using MALDI-TOF MS. This can be done accurately with ease, rapidly, and at a low cost. It is also thought to be helpful in GPB diagnosis and treatment.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1791-1800
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• 2004

Angiotensin I, a model decapeptide, was glycosylated and partially hydrolyzed with HCl (6 N, 80 $^{\circ}C$, 4 h), aminopeptidase, and carboxypeptidase Y. A single peptide mass map obtained from truncated peptides in the partial acid hydrolysate of angiotensin and its glycosylation product mixture by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry enabled sequencing of angiotensin by a combinatorial procedure. MALDI-TOF and electrospray ionization (ESI) tandem mass spectrometric results indicate that both the N-terminal amino group of aspartic acid and the guanidinium group of the second residue arginine are glycosylated.

• Macromolecular Research
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• 제11권5호
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

• Mass Spectrometry Letters
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• 제4권1호
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• pp.21-23
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• 2013

The effects of trifluoroacetic acid (TFA) were evaluated on the generation of multiply charged ions of cytochrome c in a 2-nitrophloroglucinol (2-NPG) matrix in high-vacuum, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of 1% TFA in the 2-NPG matrix solution was more effective in generating multiply charged protein ions than matrix solutions containing 0.1% or 0% TFA. Regarding the matrix itself, with 1% TFA, 2-NPG was significantly more effective in generating multiply charged ions than 2,5-dihydroxybenzoic acid (2,5-DHB). The maximum charge state of cytochrome c was +8 when using a 2-NPG matrix containing 1% TFA.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.3047-3051
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• 2014

In this paper, we describe a new method for the selective extraction and quantification of glutathione (GSH) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and maleimide-presenting gold nanoparticles (Mal-AuNPs). Our strategy utilizes the Michael addition to selectively extract GSH, from chosen samples, onto the maleimide of Mal-AuNPs. After the extraction step, the GSH bound to the AuNPs was analyzed by MALDI-TOF MS in the presence of an internal standard which was prepared by reacting Mal-AuNPs with isotope-labeled GSH ($GSH^*$). The $GSH^*$ has the same structure as GSH but a higher molecular weight, and therefore, enables absolute quantification of GSH by comparing the mass signal intensities of the GSH- and $GSH^*$-conjugated alkanethiols. Our strategy was verified by analyzing GSH-spiked fetal bovine serum and NIH 3T3 cells.

• Elastomers and Composites
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• 제41권1호
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• pp.57-62
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• 2006

1,2-dichlorobenzene 용액에서 풀러렌$[C_{60}]$과 3-chloroperoxy benzoic acid 의 반응을 고분해능 초음파 분광기를 사용하여 조사하였다. 또한 1,2-dichlorobenzene 용액에서 풀러렌$[C_{60}]$과 3-chloroperoxy benzoic acid의 반응 생성물을 MALDI-TOF-MS를 가지고 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1593-1601
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• 2017

Vibrio species are generally recognized as pathogens predominant in seafood along coastal areas. The food industry has sought to develop efficient microbial detection methods. Owing to the limits of conventional methods, this study aimed to establish a rapid identification method for Vibrio isolated from Korea, based on matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four different preparation procedures were compared to determine the appropriate means to pretreat Vibrio species, using 17 isolates and five reference strains. Extended direct transfer and full formic acid extraction methods using bacterial colonies on agar plates revealed very low identification rates. Formic acid and trifluoroacetic acid (TFA) extractions using bacterial broth cultures were also performed. All Vibrio isolates and reference strains prepared by TFA extraction were successfully identified to the species level (17/22, 77.3%) and to the genus level (5/22, 22.7%). Thus, TFA extraction was considered the most appropriate method to pretreat Vibrio species for MALDI-TOF MS. The remaining 33 isolates and two reference strains were prepared by TFA extraction and analyzed by MALDI-TOF MS. Overall, 50 isolates were identified to the species level (40/50, 80%) and to the genus level (10/50, 20%). All isolates were identified as 43 V. alginolyticus, six V. parahaemolyticus, and one V. vulnificus species. V. alginolyticus and V. parahaemolyticus were isolated from fish offal (87.5% and 12.5%, respectively), seawater (91.3%, 8.7%), and shellfish (62.5%, 37.5%), whereas V. alginolyticus and V. vulnificus were isolated from sediment (90.9% and 9.1%, respectively). This study established a reliable system of MALDI-TOF MS preparation and analysis for Vibrio identification.