• 한국축산식품학회지
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• 제34권5호
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• pp.614-621
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• 2014

This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at $121^{\circ}C$ for 15 min. These bacteriocin-producing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry.

• 한국작물학회지
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• 제48권
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• pp.58-64
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• 2003

To enjoy a healthy life, it is important to have a well-balanced diet. However, in today's society, there is an increase in the consumption of preprocessed foods and frequency of eating out. Also the western diet, which is becoming move popular worldwide, contains relatively high levels of protein and fat, and a low amount of fiber, Furthermore, the increased availability of favorite foods has created a condition were the individual diet is less variable. With these conditions, it is difficult to maintain a diet that is nutritionally balanced. With these unbalanced diets, which are difficult to change, there has been an increase in adult disease and health problems, such as colon and breast cancer, It is speculated that metabolites for carcinogens are produced from diet components and that intestinal bacteria contribute to the production of these metabolites. Therefore, it is necessary to evaluate the relationships between health, diet, and intestinal microflora. Soybean oligosaccharide is composed of water-soluble saccharides that have been extracted from soybean whey, a by-product from the production of soy protein. This is mainly a mixture of mono-, di-, tri-, and tetrasac-charides, with the principle components being the oligosaccharide raffinose and stachyose. When consumed by humans, the oligosaccharides cannot be digested in the human duodenal and small intestinal mucosa, and these are selectively utilized by beneficial bifidobacteria in intestines. The results of acute and subacute toxicity tests, soy-bean oligosaccharides were nonpoisonous. Soybean oligosaccharides promote the growth of indigenous bifido-bacteria in the colon which by their antagonistic effects, suppress the activity of putrefactive bacteria. Also, they reduce toxic metabolites, detrimental enzymes and plasma lipid, and increase in the frequency of bowel evacuation and fecal quantities. Consequently, soybean oligosaccharides as functional foods components have potential roles in the prevention and medical treatment of chronic adult diseases. The study of processing property and physiological function of soybean oligosacchavides and development of high oligosaccharide variety allow the creation of new and exciting foodstuffs that aye functional healthy.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1495-1500
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• 2008

In an attempt to develop a probiotic formulation for poultry feed, a number of lactic acid bacteria (LAB) were isolated from chicken intestinal specimens and a series of in vitro experiments were performed to evaluate their efficacy as a potential probiotic candidate. A total of 650 LAB strains were isolated and screened for their antagonistic potential against each other. Among all the isolates only three isolates (TMU121, 094 and 457) demonstrated a wide spectrum of inhibition and were thus selected for detailed investigations. All three selected isolates were able to inhibit the growth of E. coli and Salmonella species, although to variable extent. The nature of the inhibitory substance produced by the isolates TMU121 and 094 appeared to be associated with bacteriocin, as their activity was completely lost after treatment with proteolytic enzymes, while pH neutralization and catalase enzyme had no effect on the residual activity. In contrast, isolate TMU457 was able to resist the effect of proteolytic enzymes while pH neutralization completely destroyed its activity. Attempts were made to study the acid, bile tolerance and cell surface hydrophobicity of these isolates. TMU121 showed high bile salt tolerance (0.3%) and high cell surface hydrophobicity compared to the other two strains studied, while TMU094 appeared the most pH resistant strain. Based on these results, the three selected LAB isolates were considered as potential ingredients for a chicken probiotic feed formulation and were identified to species level based on their carbohydrate fermentation pattern by using API 50CH test kits. The three strains were identified as Lactobacillus fermentum TMU121, Lactobacillus rhamnosus TMU094, and Pediococcus pentosaceous TMU457.

• Journal of Ginseng Research
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• 제38권2호
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• pp.136-145
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• 2014

Background: This study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum. Methods: In total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen. Results: The bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to $25^{\circ}C$, produced no pectinase (related to root rotting) an no critical rot symptoms at low [$10^6$ colony-forming units (CFU)/mL] and high ($10^8CFU/mL$) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of $10^6CFU/mL$ than at $10^8CFU/mL$. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances. Conclusion: All of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.

• 한국미생물·생명공학회지
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• 제39권4호
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• pp.390-396
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• 2011

김치발효 후기의 우점종으로 알려진 Lactobacillus sakei의 생육을 저해하는 Leuconosotc 속 23균주가 김치로부터 분리되었고, 이들 중 가장 높은 생육저해활성을 나타낸 Leuconostoc mesenteroides CK0122 균주가 생산하는 생육 저해물질의 특성을 검토하였다. CK0122 균주의 배양 상징액을 분자량 3,000 Da을 기준으로 분획하여 동결건조한 분자량 3,000 Da 이하의 조항균물질로부터 Lb. sakei 생육저해가 확인되었고, proteinase K 처리에 의해 항균력이 소실되었기 때문에, CK0122가 생산하는 항균물질은 분자량 3,000 Da 이하의 단백질성 항균물질(bacteriocin)으로 추정된다. 분자량 3,000 Da 이하의 조항균물질은 pH 4에서 7 정도의 영역에서 최적활성을 나타내었고, $121^{\circ}C$, 15분 살균처리에 의해서도 활성이 유지되는 높은 열안정성을 나타내었으며, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, Alcaligenes xylosoxydans, Staphylococcus aureus 및 Flavobacterium sp.에 대하여 항균 활성을 나타내어 Gram 양성균 및 음성균의 제어에 적용 가능한 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1073-1079
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• 2005

To investigate plant protection, pathogenesis-related (PR) proteins and plant defense enzymes related to cell wall lignification were studied in pepper plants inoculated with antagonistic Bacillus subtilis HJ927 and pathogenic strain Phytophthora capsici. Phytophthora blight disease was reduced by $53\%$ in pepper roots when preinoculated with B. subtilis HJ927 against P. capsici. The activities of PR proteins (chitinase and ${\beta}$-1,3,-glucanase) and defense-related enzymes (peroxidase, polyphenoloxidase, and phenylalanine ammonia lyase) decreased in roots of B. subtilis+P capsid-treated plants, but increased in leaves with time. The decrease and increase were much greater in P. capsici-treated plants than in B. subtilis HJ927+P capsici-treated plants, although P. capsici-treated plants had more severe damage. Therefore, changes of enzyme activities do not seem to be directly related to plant protection. We suggest that the change of these enzymes in pathogen-treated plants may be related to plant response rather than to resistance against pathogen attacks.

• 한국균학회지
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• 제23권2호통권73호
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• pp.190-195
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• 1995

고추탄저병(Colletotrichum gloeosporioides)에 대한 생물학적방제 능력을 가지는 엽권미생물을 선발하기 위하여 38과 87종의 약용식물로부터 243균주의 세균과 51균주의 사상균 그리고 30균주의 효모를 분리하여 이들에 대하여 항진균활성검정을 in vitro 및 in vivo에서 실시한 결과는 다음과 같다. 분리된 엽권미생물 중에서 PDA 배지 대치배양에서 10 mm 이상의 생육저지대를 형성하는 4개의 엽권미생물이 선발되었다. 선발된 4개의 세균균주 KB6, KB12, KB13 및 KB14의 PDB 배양여액 중에서 KB12 균주가 균사생장 억제율이 가장 높았다. 액체배양여액 처리에서 푸른 고추보다 붉은 고추에서 방제효과가 컸다. Bacterial cell 처리에서는 푸른 고추나 붉은 고추에서도 높은 방제효과가 있었다. 선발된 4개의 세균균주들은 모두 Bacillus subtilis로 동정되었다.

• Journal of Ginseng Research
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• 제42권3호
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• pp.304-311
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• 2018

Background: Ginseng black spot disease resulting from Alternaria panax Whuetz is a common soil-borne disease, with an annual incidence rate higher than 20-30%. In this study, the bacterial strains with good antagonistic effect against A. panax are screened. Methods: A total of 285 bacterial strains isolated from ginseng rhizosphere soils were screened using the Kirby-Bauer disk diffusion method and the Oxford cup plate assay. We analyzed the antifungal spectrum of SZ-22 by confronting incubation. To evaluate the efficacy of biocontrol against ginseng black spot and for growth promotion by SZ-22, we performed pot experiments in a plastic greenhouse. Taxonomic position of SZ-22 was identified using morphology, physiological, and biochemical characteristics, 16S ribosomal DNA, and gyrB sequences. Results: SZ-22 (which was identified as Brevundimonas terrae) showed the strongest inhibition rate against A. panax, which showed 83.70% inhibition, and it also provided broad-spectrum antifungal effects. The inhibition efficacies of the SZ-22 bacterial suspension against ginseng black spot reached 82.47% inhibition, which is significantly higher than that of the 25% suspension concentrate azoxystrobin fungicide treatment (p < 0.05). Moreover, the SZ-22 bacterial suspension also caused ginseng plant growth promotion as well as root enhancement. Conclusion: Although the results of the outdoor pot-culture method were influenced by the pathogen inoculum density, the cropping history of the field site, and the weather conditions, B. terrae SZ-22 controlled ginseng black spot and promoted ginseng growth successfully. This study provides resource for the biocontrol of ginseng black spot.

• 한국식품저장유통학회지
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• 제10권2호
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• pp.224-229
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• 2003

양파 근권미생물은 양파 뿌리를 균원시료로 하여 약 250여종의 근권미생물을 순수 분리하였고 이들 중에서 길항미생물은 무름병균인 Erwinia carotovora subsp. carotovora와 시들음병균인 Fuarium oxysporium에 각각 서로 대치 배양하여 두 병원균 모두에 가장 강한 길항 효과를 나타내는 YJ-4 균주를 최종 선발하였다. 선발균주 YJ-4는 Bergey's mannual of systematic bacteriology 방법에 따라 조사하여 Bacillus 속으로 판정하였고, 세포벽 지방산을 분석하여 동정하는 Sherlock system에 의해 Bacillus ehimensis와 0.778의 유의성을 확인하였으며, 165 rDNA의 부분 염기서열(609bp)로 Bacillus ehimensis와 98.36%의 높은 유사도를 보여 길항균 YJ-4는 Bacillus ehimensis로 동정하였다. B. ehimensis YJ-4로 명명한길항균은 세균인 무름병균 (Erwinia carotovora subsp. carotovora)과 세균썩음병균 (Pseudomonas sp.)에도 길항력을 나타내었고, 진균인 잘록병균 (Rhizoctonia solani), 잎마름병균 (Stemphylium botryosum), 검은무의병균 (Alternaria porri), 검은점잎마름병균 (Septoria sp.), 잿빛곰팡이병균 (Botrytis cinerea), 흑색썩음균핵병균 (Sclerotium cepivotum), 시들음병균 (Fusarium oxysporium), 푸른곰팡이병균 (Penicillium sp.)등에도 길항 효과를 나타내었다. 특히 시들음병균인 F. oxysporium에 생육억제환의 길이가 24.8mm로 가장 높은 길항력을 나타내었다.

• The Plant Pathology Journal
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• 제39권5호
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• pp.430-448
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• 2023

Recently, strategies for controlling Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of Fusarium wilt of tomato, focus on using effective biocontrol agents. In this study, an analysis of the biocontrol and plant growth promoting (PGP) attributes of 11 isolates of loamy soil Bacillus spp. has been conducted. Among them, the isolates B.PNR1 and B.PNR2 inhibited the mycelial growth of Fol by inducing abnormal fungal cell wall structures and cell wall collapse. Moreover, broad-spectrum activity against four other plant pathogenic fungi, F. oxysporum f. sp. cubense race 1 (Foc), Sclerotium rolfsii, Colletotrichum musae, and C. gloeosporioides were noted for these isolates. These two Bacillus isolates produced indole acetic acid, phosphate solubilization enzymes, and amylolytic and cellulolytic enzymes. In the pot experiment, the culture filtrate from B.PNR1 showed greater inhibition of the fungal pathogens and significantly promoted the growth of tomato plants more than those of the other treatments. Isolate B.PNR1, the best biocontrol and PGP, was identified as Bacillus stercoris by its 16S rRNA gene sequence and whole genome sequencing analysis (WGS). The WGS, through genome mining, confirmed that the B.PNR1 genome contained genes/gene cluster of a nonribosomal peptide synthetase/polyketide synthase, such as fengycin, surfactin, bacillaene, subtilosin A, bacilysin, and bacillibactin, which are involved in antagonistic and PGP activities. Therefore, our finding demonstrates the effectiveness of B. stercoris strain B.PNR1 as an antagonist and for plant growth promotion, highlighting the use of this microorganism as a biocontrol agent against the Fusarium wilt pathogen and PGP abilities in tomatoes.