• Food Science and Preservation
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• v.30 no.1
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• pp.28-41
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• 2023

Non-aflatoxigenic Aspergillus oryzae and aflatoxigenic A. flavus cannot be clearly identified by partial sequencing of the internal transcribed spacer (ITS) and 18S ribosomal ribonucleic acid (18S rRNA) regions. This study aimed to compare the accuracy among three aflatoxin detection methods using ultra-performance liquid chromatography (UPLC), high-performance liquid chromatography (HPLC), and an enzyme-linked immunosorbent assay (ELISA) kit and to select the non-aflatoxigenic Aspergillus sp. isolated from soybean paste. All analytical methods were suitable according to the international standards of Codex Alimentarius FAO-WHO (CODEX) or the Ministry of Food and Drug Safety (MFDS). UPLC exhibited the best of limit of detection (LOD) and limit of quantification (LOQ). Based on UPLC, HPLC, and the ELISA kit assay, the P5 and P7 strains isolated from soybean paste had 1,663.49, 1,468.12, and >20 ㎍/kg and 1,470.08, 1,056.73, and >20 ㎍/kg, respectively, detected and re-identified as A. flavus. In contrast, the P3 and P4 strains (A. oryzae), which were detected below the MFDS standards in all assays, were confirmed as non-aflatoxigenic fungi. Among the methods evaluated for quantitative analysis of aflatoxin, UPLC and HPLC are superior in terms of accuracy, and the ELISA kit rapidly detects low concentrations of aflatoxin. Furthermore, this study demonstrates that any Aspergillus sp. isolated for use as a fermentation starter should be analyzed for potential aflatoxin production using UPLC and HPLC for accurate quantitative analysis or ELISA for the rapid detection of low-level concentrations of aflatoxin.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.651-656
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• 2013

Human schistosomiasis caused by Schistosoma japonicum and Schistosoma mekongi is a chronic and debilitating helminthic disease still prevalent in several countries of Asia. Due to morphological similarities of cercariae and eggs of these 2 species, microscopic differentiation is difficult. High resolution melting (HRM) real-time PCR is developed as an alternative tool for the detection and differentiation of these 2 species. A primer pair was designed for targeting the 18S ribosomal RNA gene to generate PCR products of 156 base pairs for both species. The melting points of S. japonicum and S. mekongi PCR products were $84.5{\pm}0.07^{\circ}C$ and $85.7{\pm}0.07^{\circ}C$, respectively. The method permits amplification from a single cercaria or an egg. The HRM real-time PCR is a rapid and simple tool for differentiation of S. japonicum and S. mekongi in the intermediate and final hosts.

• Korean Journal of Environmental Biology
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• v.25 no.4
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• pp.349-355
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• 2007

Phylogeny of the species mainly from the genus Amynthas in family Megascolecidae was inferred at the molecular level using ITS regions in rDNA. With 26 species of earthworms from 10 genera in 2 families, a stretch comprising the 3'-end of the 18S rRNA, ITS1, 5.8S rRNA, ITS2, and 5' end of 28S rRNA was amplified by applying the primers ITS-1, ITS-2. Phylogenetic analyses of nucleotide sequences with a help of MP, NJ, and QP yielded 5 groups similarly. Genus Amynthas was separated largely into two groups, Korean and Philippine origins. Species grouped into the 1st were Amynthas jirensis, A. agrestis, A. gucheonensis, A. sopaikensis, A. bubonis, A. multimaculatus, A. koreanus, A. dageletensis, A. heteropodus, A. odaesanensis, Pontoscolex sp., Pheretima sp. 1, and Dendropheretima banahawensis. Amynthas halconensis, A. isarogensis, A. mindrooensis, Pithemera sp. 2, Pithmera sp. 1, and Pleionogaster sp. clustered into one clade forming the 2nd group. Polypheretima sp. 1 and polypheretima. sp. 2 stayed closely together representing a separate monophyletic status, forming the 3rd group, apart from species in other genera. Archipheretima sp. falls into the 4th group. Distinct morphological characteristics from Archipheretima also coinsides with its branching away from others in the previously reported molecular analyses. Similar to Perionyx excavatus that has been selected as an outgroup, Aporrectodea tuberculata also showed a long branch in the phylogram, but it differed from other 24 species included in the analyses. Unlike others, for example, its habitat is very closely related to that of man.

• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.215-222
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• 2012

Species-specific $TaqMan^{(R)}$ probe-based real-time PCR assays were developed for detection of beef, pork, chicken, duck, goose and turkey. The primer and probe sets used in this study were designed to be complementary to fibroblast growth factor (FGF) for cattle and pig, mitochondrial NADH dehydrogenase (ND) subunit 3 and ND2 for chicken and duck, 12S rRNA for goose and turkey, respectively. As internal positive control we used conserved region in the ribosomal 18S RNA gene to ensure the accuracy of the detection of target DNA by real-time PCR. We confirmed that real-time PCR assays with the primer and probe sets were positive for cattle, pig and chicken intended target animal species with no cross-reactivity with other non-target animal species. Only >50 ng DNA of beef show cross-reactivity in the determination of duck. Using species-specific primer and probe sets, it was possible to detect amounts of 0.1 ng DNA of cattle and pig, 1.0 pg DNA of chicken, duck and turkey, and 0.1 pg DNA of goose for raw samples, respectively. The detection limits were 0.1 ng DNA of cattle, 1.0 ng DNA of pig and 1.0 pg DNA of chicken for DNA mixtures (beef, pork and chicken) extracted from heat-treated ($121^{\circ}C$/5 min) meat samples. In conclusion, it can be suggested that the $TaqMan^{(R)}$ probe-based assay developed in this study might be a rapid and specific method for the identification of meat species in raw or cooked meat products.

• Animal cells and systems
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• v.6 no.1
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• pp.13-18
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• 2002

Phylogenetic relationships of Korean Acidiella species were tested using mitochondrial 16S ribosomal RNA gene sequences. We used 16 published sequences as outgroup, and 10 new sequences for nine Korean Acidiella species as ingroup. The number of aligned sites was 1,281 bp, but 1,135 bp were used for the analysis after excluding sites with missing data or gaps. Among these 1,135 sites, 464 sites were variable and 340 were informative for parsimony analysis. Phylogenetic information was extracted from this data set using neighbor-joining, maximum likelihood and maximum parsimony methods and compared to a morphology-based phylogenetic hypothesis. Our molecular data suggest that: (1) the tribe Trypetini appears to be monophyletic even when the nine additional Acidiella species are added to our previous phylogenetic analysis; (2) all the Korean Acidiella species belong to the Trypeta group, but the genus Acidiella is not supported as monophyletic; (3) the close relationship of A. circumvaga, A. issikii, and A. sapporensis is supported; (4) the close relationship of A. pachypogon and two additional new Acidiella species is strongly supported; and (5) the possible presence of two or more cryptic species among the specimens previously identified as A. obscuripennis is suggested. Sequence data from the mitochondrial 16S rDNA allowed us to better understand the systematic status of Korean Acidiella species. They indicated that the current concept about the genus Acidiella is insufficient and needs to be refined further. This study also showed a few interesting relationships, that had not been recognized by morphological study alone. Based on this study, we were able to plan further experiments to analyze relationships within the Trypeta Group.

• Parasites, Hosts and Diseases
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• v.57 no.5
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• pp.461-467
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• 2019

Avian trematodes, Urogonimus turdi (Digenea: Leucochloridiidae), were collected from the intestine of wild birds, Zoothera aurea, 2013-2017 in the Daejeon Metropolitan City, Korea. The body was ellipsoidal, attenuated and/or round ends, 1,987-2,120 long and $819-831{\mu}m$ wide. The oral sucker was subterminal, rounded anteriorly, and $308-425{\times}351-432{\mu}m$ in size; the prepharynx and esophagus were almost lacking; pharynx was well-developed, $142-179{\times}78-170{\mu}m$ in size; intestine narrow, bifurcating just after pharynx, ascending to the oral sucker before looping posteriorly and terminating near the posterior end; ventral sucker larger, in almost median, $536-673{\times}447-605{\mu}m$ and approximately 1.5 times larger than oral sucker. A phylogenetic tree constructed with 18S ribosomal RNA showed inter- and intraspecific relationships. Based on these morphological and molecular findings, we report here a U. turdi from White's thrushes in Korea.

• Archives of Plastic Surgery
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• v.39 no.1
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• pp.18-24
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• 2012

Background : Infection caused by rapidly growing mycobacteria (RGM) is not uncommon, and the prevalence of RGM infection has been increasing. Clinical diagnosis is difficult because there are no characteristic clinical features. There is also no standard antibiotic regimen for treating RGM infection. A small series of patients with RGM infections was studied to examine their treatments and outcomes. Methods : A total of 5 patients who had developed postoperative infections from January 2009 to December 2010 were retrospectively reviewed. Patients were initially screened using a mycobacteria rapid screening test (polymerase chain reaction [PCR]-reverse blot hybridization assay). To confirm mycobacterial infection, specimens were cultured for nontuberculous mycobacteria and analyzed by 16 S ribosomal RNA and rpoB gene PCR. Results : The patients were treated with intravenous antibiotics during hospitalization, and oral antibiotics were administered after discharge. The mean duration of follow-up was 9 months, and all patients were completely cured of infection with a regimen of a combination of antibiotics plus surgical treatment. Although none of the patients developed recurrence, there were complications at the site of infection, including hypertrophic scarring, pigmentation, and disfigurement. Conclusions : Combination antibiotic therapy plus drainage of surgical abscesses appeared to be effective for the RGM infections seen in our patients. Although neither the exact dosage nor a standardized regimen has been firmly established, we propose that our treatment can provide an option for the management of rapidly growing mycobacterial infection.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8281-8285
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• 2016

Background: Helicobacter pylori is a cause of chronic gastritis, peptic ulcer disease, and gastric malignancy, infection being a serious health problem in Thailand. Recently, clarithromycin resistant H. pylori strains represent the main cause of treatment failure. Therefore this study aimed to determine the prevalence and pattern of H. pylori resistance to clarithromycin in Suranaree University of Technology Hospital, Suranree University of Technology, Nakhon Ratchasima, Northeastern Thailand, Nakhon Ratchasima province, northeast of Thailand. Materials and Methods: This hospital-based cross-sectional study was carried out between June 2014 and February 2015 with 300 infected patients interviewed and from whom gastric mucosa specimens were collected and proven positive by histology. The gastric mucosa specimens were tested for H. pylori and clarithromycin resistance by 23S ribosomal RNA point mutations analysis using real-time polymerase chain reactions. Correlation of eradication rates with patterns of mutation were analyzed by chi-square test. Results: Of 300 infected patients, the majority were aged between 47-61 years (31.6%), female (52.3%), with monthly income between 10,000-15,000 Baht (57%), and had a history of alcohol drinking (59.3%). Patient symptoms were abdominal pain (48.6%), followed by iron deficiency anemia (35.3%). Papaya salad consumption (40.3%) was a possible risk factor for H. pylori infection. The prevalence of H. pylori strains resistant to clarithromycin was 76.2%. Among clarithromycin-resistant strains tested, all were due to the A2144G point mutation in the 23S rRNA gene. Among mutations group, wild type genotype, mutant strain mixed wild type and mutant genotype were 23.8%, 35.7% and 40.5% respectively. With the clarithromycin-based triple therapy regimen, the efficacy decreased by 70% for H. pylori eradication (P<0.01). Conclusions: Recent results indicate a high rate of H. pylori resistance to clarithromycin. Mixed of wild type and mutant genotype is the most common mutant genotype in Nakhon Ratchasima province, therefore the use of clarithromycin-based triple therapy an not advisable as an empiric first-line regimen for H. pylori eradication in northeast region of Thailand.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.255-262
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• 2010

Strain BCNU 2001 was isolated from soil samples collected from Tea-baek Mountain area. The biochemical characteristics and 16S ribosomal RNA gene sequences of the isolate revealed that the strain belonged to the Pseudomonas aeruginosa. The supernatants had an antimicrobial effect on various kind of bacteria and fungi. Especially BCNU 2001 was able to greatly inhibit the growth of Micrococcus luteus, Proteus mirabilis, Proteus vulgaris, and Aspergillus niger, and its inhibition zone was measured as 18.5 mm against Micrococcus luteus, 19.0mm against Proteus mirabilis, 17.0mm against Proteus vulgaris, and 13.5 mm against Aspergillus niger, respectively. Hexane and dichloromethane extracts of BCNU 2001 exhibited significant activity against bacteria, and dichloromethane and ethylacetate extracts showed significant activity against fungi. Pseudomonas strain BCNU 2001 was also determined to have antimicrobial peptide against various microorganisms including Gram positive bacteria, Gram negative bacteria and fungi. The obtained results may provide preliminary support for the usefulness of Pseudomonas strain BCNU 2001.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.277-279
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• 2018

전 세계적으로 Helicobacter pylori의 항생제 내성률은 지속적으로 증가하고 있으며, 기존의 제균 치료에 실패한 H. pylori 감염 환자들에 대한 효과적인 구제요법(rescue therapy)의 필요성 역시 증가하고 있다. 이 연구는 두 개 기관, 공개, 평행 그룹, 무작위 배정 연구로서 불응성 H. pylori 감염 환자들의 구제요법으로 유전자형 내성을 기반한 치료(genotype resistance-guided therapy)와 경험적 치료(empirical therapy) 중 어느 것이 보다 효과적인지를 비교하고자 하였다. 2012년 10월부터 2017년 9월까지 20세 이상의 불응성 H. pylori 감염 환자들을 대상으로 하였으며, 불응성 H. pylori 감염은 과거 두 종류 이상의 H. pylori 제균 치료를 받았음에도 불구하고 H. pylori 제균에 실패한 환자들로 정의하였다. 이들에게서 한 군은 14일간의 유전자형 내성을 기반한 순차 치료(n=21 in trial 1, n=205 in trial 2)를, 다른 한 군은 환자들의 과거 제균 치료 종류를 감안한 14일간의 경험적 순차 치료(n=20 in trial 1, n=205 in trial 2)를 시행하였다. 순차 치료법은 첫 7일은 esomeprazole 40 mg과 amoxicillin 1 g을 하루 두 번 복용한 다음, 나머지 7일은 esomeprazole 40 mg과 metronidazole 500 mg, 그리고 1) levofloxacin 250 mg 또는 2) clarithromycin 500 mg 또는 3) tetracycline 500 mg을 하루 두 번 복용하는 것으로 구성하였다. 23S ribosomal RNA (rRNA)나 gyrase A에 대한 내성 관련 돌연변이 여부는 direct sequencing을 통한 중합효소연쇄반응(polymerase chain reaction, PCR) 검사를 이용하였고, 제균 성공 여부는 요소호기검사를 통해 확인하였다. 일차 결과 지표는 치료 방법에 따른 제균율로 정하였다. Trial 1에서는 tetracycline 대신 doxycycline 100 mg을 사용하였는데, 제균 성공률이 유전자형 내성을 기반한 치료군에서는 17명(81%), 경험적 치료군에서는 12명(60%)으로 나타났다(P=0.181). 하지만, 다른 순차 치료군들과 비교하였을 때, doxycycline을 포함한 순차 치료군의 제균율이 현저히 낮은 것으로 나타나서(15/26, 57.7%) doxycycline을 포함한 순차 치료법은 종결하기로 하고, trial 2부터는 doxycycline 대신 tetracycline으로 교체하여 연구를 지속하였다. Trial 2의 intention-to-treat (ITT) 분석 결과, 유전자형 내성을 기반한 치료군에서는 160/205명(78%), 경험적 치료군에서는 148/205명(72.2%)으로 두 그룹 간의 통계적인 제균율의 차이는 보여주지 못하였다(P=0.170). 부작용 및 환자 순응도에서도 양 군 간의 의미 있는 차이는 없었다. 따라서, 두 종류 이상 H. pylori 제균 치료에 실패한 환자들이라고 할지라도 기존의 제균 치료력을 바탕으로 적절한 경험적 치료를 시행하는 것은 유전자형 내성을 기반한 치료 정도의 효과는 있으며 접근성, 비용, 환자들의 선호도 등의 여러 가지 부가적인 사항들을 고려할 때, 제균 치료력을 고려한 경험적 치료는 간단한 수준의 유전자형 내성을 기반한 치료의 대안으로 받아들여질 수 있을 것으로 제안하였다.