• Food Science and Biotechnology
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• 제17권5호
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• pp.925-930
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• 2008

Norovirus has become the most common cause of human gastroenteritis in developed countries. Detection procedures of foodborne viruses from foods require several steps. The concentration step using polyethylene glycol (PEG) is time-consuming and the detection efficiency of reverse transcription-polymerase chain reaction (RT-PCR) is affected by inhibitors from food components. In this study, a rapid detection method based on buoyant density centrifugation was developed to replace the time-consuming chloroform-polyethylene glycol-Tris Tween method. Feline calicivirus that belongs to the family Caliciviridae was used as a surrogate model for norovirus. After artificial inoculation of feline calcivirus (FCV) to oyster and lettuce, 830 ${\mu}L$ of homogenized sample suspension was layered on the top of 670 ${\mu}L$ 20% percoll and centrifuged. Then RNA extraction step was proceeded with the supernatant. By varying several physical conditions, the detection limits were lowered to $2.4{\times}10^2$ PFU per 1 g in oyster and $2.4{\times}10^0$ PFU per 1 g in lettuce. The protocol obtained in this study could be used to develop new detection method for norovirus in foods.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.9-18
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• 2017

Nine bacilli with fibrinolytic activities were isolated from doenjang, a traditional Korean fermented soy food. Among them, RSB34 showed the strongest activity and was identified as Bacillus amyloliquefaciens by 16S rRNA and recA gene sequencing. During growth on LB up to 96 h, RSB34 showed the highest fibrinolytic activity ($83.23mU/{\mu}l$) at 48 h. Three bands of 23, 27, and 42 kDa in size were observed when the culture supernatant was analyzed by SDS-PAGE and 27 and 42 kDa bands by fibrin zymography. The gene encoding the 27 kDa fibrinolytic enzyme AprE34 was cloned by PCR. BLAST analyses confirmed that the gene was a homolog to genes encoding AprE-type proteases. aprE34 was overexpressed in Escherichia coli BL21(DE3) using pET26b(+). Recombinant AprE34 was purified and examined for its properties. The $K_m$ and $V_{max}$ values of recombinant AprE34 were $0.131{\pm}0.026mM$ and $16.551{\pm}0.316{\mu}M/l/min$, respectively, when measured using an artificial substrate, N-succinyl-ala-ala-pro-phe-p-nitroanilide. aprE34 was overexpressed in B. subtilis WB600 using pHY300PLK. B. subtilis transformants harboring pHYRSB34 (pHY300PLK with aprE34) showed higher fibrinolytic activity than B. amyloliquefaciens RSB34.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1510-1518
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• 2015

In this work, we wanted to develop a probiotic from famous longevity villages in Korea. We visited eight longevity villages in Korea to collect fecal samples from healthy adults who were aged above 80 years and had regular bowel movements, and isolated lactic-acid-producing bacteria from the samples. Isolated colonies that appeared on MRS agar containing bromophenol blue were identified by means of 16S rRNA sequencing, and 102 of the isolates were identified as lactic-acid-producing bacteria (18 species). Lactobacillus fermentum was the most frequently found species. Eight isolates were selected on the basis of their ability to inhibit the growth of six intestinal pathogens (Escherichia coli O157:H7, Salmonella enterica subsp. enterica Typhimurium, Salmonella enterica subsp. enterica Enteritidis, Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes) and their susceptibility to 15 antimicrobial agents. Among these eight isolates, four Lactobacillus fermentum isolates were found not to produce any harmful enzymes or metabolites. Among them, Lactobacillus fermentum isolate no. 24 showed the strongest binding to intestinal epithelial cells, the highest immune-enhancing activity, anti-inflammation activity, and anti-oxidation activity as well as the highest survival rates in the presence of artificial gastric juice and bile solution. This isolate, designated Lactobacillus fermentum PL9988, has all the characteristics for a good probiotic.

• Mycobiology
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• 제42권2호
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• pp.206-209
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• 2014

In this study, we identified the causative agent of stem-end rot in potatoes that were grown in Gangwon alpine areas of Korea in 2013. The disease symptoms included appearance of slightly sunken circular lesion with corky rot on the potato surface at the stem-end portion. The fungal species isolated from the infected potatoes were grown on potato dextrose agar and produced white aerial mycelia with dark violet pigments. The conidiophores were branched and monophialidic. The microconidia had ellipsoidal to cylindrical shapes and ranged from $2.6{\sim}11.4{\times}1.9{\sim}3.5{\mu}m$ in size. The macroconidia ranged from $12.7{\sim}24.7{\times}2.7{\sim}3.6{\mu}m$ in size and had slightly curved or fusiform shape with 2 to 5 septate. Chlamydospores ranged from $6.1{\sim}8.1{\times}5.7{\sim}8.3{\mu}m$ in size and were present singly or in pairs. The causal agent of potato stem-end rot was identified as Fusarium oxysporum by morphological characterization and by sequencing the internal transcribed spacer (ITS1 and ITS4) regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of F. oxysporum. To the best of our knowledge, this is the first study to report that potato stem-end rot is caused by F. oxysporum in Korea.

• The Plant Pathology Journal
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• 제29권2호
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• pp.168-173
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• 2013

Apple ring rot disease, caused by Botryosphaeria dothidea (Moug. ex. Fr) Ces. et de Not., is one of the most important diseases on apple fruits. In this study, strain 9001 isolated from healthy apple fruits from an infested orchard was evaluated for its biocontrol activity against apple ring rot in vitro and in vivo. Strain 9001 showed obvious antagonistic activity to B. dothidea YL-1 when plated on potato dextrose agar. Soaking healthy apples in the bacterial suspensions of strain 9001 prior to artificial inoculation of fungal pathogen resulted in a dramatic decrease in disease incidence when compared to the control. Moreover, either field application in the growth season or postharvest treatment of apples from infected orchards with bacterial suspensions of strain 9001 resulted in significantly reduced disease incidence within the storage period for 4 months at room temperature. Based on the phylogenetic analysis of 16S rRNA and the gyrA gene, strain 9001 was identified as Bacillus amyloliquefaciens. These results indicated that B. amyloliquefaciens 9001 could be a promising agent in biocontrol of apple ring rot on fruit, which might help to minimize the yield loss of apple fruit during the long postharvest period.

• 한국미생물·생명공학회지
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• 제38권2호
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• pp.216-221
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• 2010

본 연구는 탄산칼슘형성세균을 이용하여 시멘트-모래 모르타르의 압축강도증진 및 균열보수의 응용에 연구의 목적이 있다. 독도로부터 분리한 7가지의 탄산칼슘형성세균을 16S rDNA 염기서열을 이용하여 동정했다. 고체배지상의 콜로니 주변부에 형성되는 광물결정을 확인했다. Urea-$CaCl_2$ 배지에서 형성되는 광물의 모양은 종 특이적인 것을 확인했다. Arthrobacter nicotinovorans KNUC601, Microbacterium resistens KNUC602, Agrobacterium tumefaciens KNUC603, Exiguobacterium acetylicum KNUC604, 및 Bacillus thuringiensis KNUC606균주는 인위적으로 만든 모르타르 균열부위를 메우는 것을 확인했다. Stenotrophomonas maltophilia KNUC605가 혼입된 시멘트-모래 모르타르는 음성대조구에 비해 14.7%정도 강도가 증가됐다.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1621-1628
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• 2012

The agar-degrading bacterium GNUM-1 was isolated from the brown algal species Sargassum serratifolium, which was obtained from the West Sea of Korea, by using the selective artificial seawater agar plate. The cells were Gram-negative, $0.5-0.6{\mu}m$ wide and $2.0-2.5{\mu}m$ long curved rods with a single polar flagellum, forming nonpigmented, circular, smooth colonies. Cells grew at $20^{\circ}C-37^{\circ}C$, between pH 5.0 and 9.0, and at 1-10% (w/v) NaCl. The DNA G+C content of the GNUM-1 strain was 45.5 mol%. The 16S rRNA sequence of the GNUM-1 was very similar to those of Alteromonas stellipolaris LMG 21861 (99.86% sequence homology) and Alteromonas addita $R10SW13^T$(99.64% sequence homology), which led us to assign it to the genus Alteromonas. It showed positive activities for agarase, amylase, gelatinase, alkaline phosphatase, esterase (C8), lipase (C14), leucine arylamidase, valine arylamidase, ${\alpha}$-chymotrypsin, acid phosphatase, naphthol-AS-BI-phosphohydrolase, ${\alpha}$-galactosidase, ${\beta}$-galactosidase, ${\beta}$-glucosidase, catalase, and urease. It can utilize citrate, malic acid, and trisodium citrate. The major fatty acids were summed feature 3 (21.5%, comprising $C_{16:1}{\omega}7c/iso-C_{15:0}$ 2-OH) and C16:0 (15.04%). On the basis of the variations in many biochemical characteristics, GNUM-1 was considered as unique and thus was named Alteromonas sp. GNUM-1. It produced the highest agarase activity in modified ASW medium containing 0.4% sucrose, but lower activity in rich media despite superior growth, implying that agarase production is tightly regulated and repressed in a rich nutrient condition. The 30 kDa protein with agarase activity was identified by zymography, and this report serves as the very first account of such a protein in the genus Alteromonas.

• Parasites, Hosts and Diseases
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• 제57권6호
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• pp.699-704
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• 2019

Anisakiasis (anisakidosis) refers to a foodborne zoonosis caused by ingesting raw or undercooked marine fish or cephalopods infected with anisakid larvae. The present study was performed to investigate the prevalence of anisakid larvae in anchovies (Engraulis japonica) purchased from 2 local markets in Gyeongsangnam-do, the Republic of Korea (=Korea), during 2018-2019. Anchovies were transported to our laboratory and examined by pepsin-HCl artificial digestion technique followed by microscopic observations and molecular analyses. The overall prevalence of anisakid larvae was 19.5% (39/200), from which a total of 51 larvae (av. 1.3 larvae/infected anchovy) were recovered. Sequencing of the larvae targeting the ITS region, including ITS1, 5.8S rRNA, and ITS2 genes confirmed the species of larvae as Anisakis pegreffii (54.9%; 28/51), Hysterothylacium sinense (23.5%; 12/51), and Hysterothylacium aduncum (21.5%; 11/51). The results suggested that anchovies could be a potential source of human anisakiasis in Korea.

• Journal of Plant Biotechnology
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• 제45권4호
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• pp.306-314
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• 2018

Korean ginseng (Panax ginseng) has long been cultivated as an important economic medicinal plant. Owing to the seasonal and long-term agricultural cultivation methods of Korean ginseng, they are always vulnerable to various environmental stress conditions. ABSCISIC ACID (ABA) is an essential plant hormone associated with seed development and diverse abiotic stress responses including drought, cold and salinity stress. By modulating ABA responses, plants can regulate their immune responses and growth patterns to increase their ability to tolerate stress. With recent advances in genome sequencing technology, we first reported the functional features of genes related to canonical ABA signaling pathway in P. ginseng genome. Based on the protein sequences and functional genomic analysis of Arabidopsis thaliana, the ABA related genes were successfully identified. Our functional genomic characterizations clearly showed that the ABA signaling related genes consisting the ABA receptor proteins (PgPYLs), kinase family (PgSnRKs) and transcription factors (PgABFs, PgABI3s and PgABI5s) were evolutionary conserved in the P. ginseng genome. We confirmed that overexpressing ABA related genes of P. ginseng completely restored the ABA responses and stress tolerance in ABA defective Arabidopsis mutants. Finally, tissue and age specific spatio-temporal expression patterns of the identified ABA-related genes in P. ginseng tissues were also classified using various available RNA sequencing data. This study provides ABA signal transduction related genes and their functional genomic information related to the growth and development of Korean ginseng. Additionally, the results of this study could be useful in the breeding or artificial selection of ginseng which is resistant to various stresses.

• 한국유기농업학회지
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• 제26권4호
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• pp.649-660
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• 2018

Colletotrichum acutatum에 의해 발생하는 고추탄저병을 방제하기 위해 토양 근권으로부터 분리한 미생물 중 길항효과가 있는 미생물을 선발하여 주요 작물병원균에 대한 항균활성 효과와 포장에서의 방제효과를 검정하였다. 기내 대치배양법을 이용한 길항력을 검정하였을 때, CAB13001 균주는 고추 탄저병을 일으키는 Colletotrichum acutatum을 포함한 식물 병원균 Sclerotinia cepivorum, Sclerotinia sclerotium, Botrytis cinerea에 대한 뛰어난 항균활성 효과를 보였다. 또한 풋고추를 이용한 생체 검정에서 선발균주는 고추 탄저병의 병반진전 억제효과가 우수하였으며, 포장에서의 방제가 역시 무처리 대비 82.4%로 매우 우수하였다. 이러한 결과로 볼 때 CAB13001 균주는 공기 전염을 하는 고추 탄저병의 생물적 방제제로 매우 유용할 것으로 판단된다. 한편, 본 연구에 사용된 길항미생물 CAB13001 균주는 16s rRNA gene의 계통학적 위치를 분석한 결과 Burkholderia lata로 동정하였다.