• 한국미생물·생명공학회지
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• 제22권3호
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• pp.309-315
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• 1994

Selective agar media were constructed for the counting of bifidobacteria in dairy produ- cts containing bifidobacteria, lactobacilli and streptococci. This media containing antibiotics inhibited the growth of lactobacilli and streptococci at less than 10$^{5}$ cfu/ml, but had no influence on the recovery of bifidobacteria. In order to inhibit the growth of 10$^{5}$ cfu/ml of lactobacilli and streptoco- cci, the addition of 1.0~2.0 $\mu$g/ml of tetracycline in BL agar medium was needed. When 25 $\mu$g/ml of neomycin and paromomycin were mixed with 1.0 $\mu$g/ml of tetracycline in BL agar medium, it was able to inhibit the growth of 10$^{6}$ cfu/ml of lactobacilli and streptococci but had a little negative effect on the recovery of colonies of bifidobacteria. The results revealed that the BL agar medium containing 1.0 $\mu$g/ml of tetracycline was suitable to count the cell number of bifidobacteria selecti- vely in the presence of a 1 to 10$^{5}$-fold excess of L. casei, L. acidophilus and S. salivarius subsp.thermophilus.

• 한국식품과학회지
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• 제6권1호
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• pp.36-41
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• 1974

한천 원조(原藻)로서 완도(莞島), 여수(麗水), 남해(南海)지역에서 수집한 꼬시레기 및 우무가사리와 마닐라에서 수입한 알카리 처리된 꼬시레기, 그리고 알진산원조로서 제주(濟州)지역에서 수집한 감태에서 한천 또는 알진산의 추출수율을 증대시키기 위한 실험을 수행하여 다음과 같은 결과를 얻었다. 국내산 원조(原藻)로 부터의 한천 추출에 있어서 꼬시레기는 갈마선(線) 처리효과가 없었으나 우무가사리는 8-10%의 수율증가를 보였다. 마닐라산 원조(原藻)에서는 1.5 Mrad의 감마선 조사(照射)에 의하여 25-30%의 한천수율이 증가하였고 이와 같이 제조된 한천은 이화학적 특성이 대조구와 비슷하였다. 한국산 감태로부터의 알진산 추출에 있어서 0.3 Mrad의 감마선 조사(照射)는 6%의 수율증가를 보였다.

• 한국균학회지
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• 제51권2호
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• pp.101-109
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• 2023

A fungal strain designated KNUF-21-66Q1 was isolated from soil in Chungcheongbuk Province, Korea. Moderate growth of colonies was observed on potato dextrose agar, oatmeal agar (OA), malt extract agar, and cornmeal agar media at 25℃, and the detailed morphology was examined on OA medium. The colonies on OA medium were flat, had entire margin, hyaline, and yellow concentric rings in 3-4 weeks. Conidiomata were pycnidial, solitary or clustered, globose to subglobose, black-brown, and 300-500 ㎛ in diameter. Conidiogenous cells were smooth, hyaline, globose to ampulliform, and 6.0-9.0×3.0-6.0 ㎛ in size (n=15). Conidia were hyaline to pale brown, slightly golden, obovoid to slightly ellipsoidal, smooth, guttulate, and 3.0-4.7×2.1-3.3 ㎛ in size (n=100). The strain was confirmed based on phylogenetic analysis using internal transcribed spacer regions, the partial 28S rDNA of large subunit, and β-tubulin gene sequences. The morphological observations and phylogenetic analysis revealed that the strain KNUF-21-66Q1 was similar to the previously described Paraconiothyrium kelleni. To our knowledge, this is the first report of P. kelleni in Korea.

• Mycobiology
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• 제51권3호
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• pp.186-194
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• 2023

In July 2021, wilting symptoms were observed in adult and seedling hemp (Cannabis sativa L. cv. Cherry Blossom) plants grown in a greenhouse. As the disease progressed, yellowing and wilting symptoms on the leaves developed, resulting in whole plant death. In seedling plants, typical damping-off symptoms were observed. To identify the pathogen, the roots of diseased plants were sampled, surface sterilized, and cultured on potato dextrose agar (PDA) media. From the culture, 4 different fungal isolates were recovered and purely cultured. Each fungal isolate showed distinct growth shapes and color development on malt extract agar, oatmeal agar, sabouraud dextrose agar, and PDA media. Microscopic observation and molecular identification using ribosomal DNA internal transcribed spacer sequencing identified them as 3 Fusarium spp. and 1 Thielaviopsis paradoxa. Additional sequencing of elongation factor 1-alpha and b-tubulin regions of 3 Fusarium spp. revealed that 2 of them are Fusarium solani, and the other one is Fusarium proliferatum. To examine which isolate can act as a causal agent of wilt disease of hemp, each isolate was tested for their pathogenicity. In the pathogenicity test, F. solani AMCF1 and AMCF2, and F. proliferatum AMCF3, but not T. paradoxa AMCF4, were able to cause wilting disease in hemp seedlings. Therefore, we report that F. solani AMCF1 and AMCF2, and F. proliferatum AMCF3 as causal agents of Fusarium wilt of hemp plants. To our knowledge, this is the first report of the wilt disease of C. sativa L. caused by Fusarium spp. in Korea.

• Journal of Dairy Science and Biotechnology
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• 제42권1호
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• pp.9-17
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• 2024

This study aimed to evaluate the appropriateness of MRS-C (0.05% L-cystein; pH 5) and BHI-CM (0.05% L-cystein, 0.5% mucin) agars for the selective isolation of bifidobacteria in fecal samples compared to blood-liver-NPNL (BL-NPNL) agar. Over 200 isolated colonies were characterized morphologically and biochemically. Genomic DNA was extracted from pure cultures of the isolated strains, followed by PCR amplification of the 16S rRNA gene. Bifidobacterium longum and B. animalis were selectively isolated from MRS-C agar and Lactobacillus acidophilus and Enterococcus avium were also isolated. B. longum, B. faecale, and B. animalis were isolated from feces on BHI-CM agar; however, different Bacteroides strains (including Bac. fragilis, Bac. kiribbi, Bac. ovatus, Bac. koreensis, and Bac. salyersiae) were also detected. BL-NPNL agar successfully isolated B. longum and Bacillus, while other Bifidobacterium and Bacteroides species could not grow owing to the presence of antibiotics in the medium. The use of antibiotics in a medium can enhance the selectivity; however, antibiotics may inhibit the growth of certain bacteria in a sample. Hence, adjusting pH or adding non-antibiotic nutrients to the medium is more advantageous, than relying on antibiotics.

• 한국해양바이오학회지
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• 제2권3호
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• pp.142-148
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• 2007

Agar로부터 oligosaccharides를 제조하기 위하여 효소 (agarase)를 이용한 분해법이 시도되면서 agarase의 균주의 분리 및 유전자에 대한 많은 연구가 수행되고 있다. 본 연구에서는 해양으로부터 agarase를 생성하는 균주를 분리 동정하고 균주의 특성을 조사하였다. 분리된 균주는 AS-3균주는 16S rDNA 염기서열분석에 의하여 Algibacter lectus AS-3로 동정되었다. 정제된 효소의 최적 활성 조건 및 agar 분해산물의 항산화활성을 조사하였다. 분리된 균주의 최적배양조건은 marine broth 2216에서 온도 $27^{\circ}C$, pH 7일 때 가장 균주의 생육이 높았다. Agarase 효소는 salt 침전, ion exchange와 gel filtration chromatography에 의해 9.6 units/mg으로 6.9배 정제되었다. 최적 효소활성은 온도 $40{\sim}50^{\circ}C$, pH 7일 때 나타났다. Agar 첨가한 배지에 agar 분해균을 접종한 후 분해산물의 시간에 따른 항산화활성은 12시간 배양 후 62%의 가장 높은 전자소거능 (EDA)을 나타내었다.

• KSBB Journal
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• 제21권5호
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• pp.389-393
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• 2006

제주도 연안에서 분리 동정된 한천분해효소를 생산하는 Agarivorans sp. JA-1의 배양특성을 연구하였다. 균주가 기질로 이용하는 한천은 배지 내의 한천의 농도가 0.2%일 때 가장 효율적인 성장을 하였으며 4종의 탄소원에 대해서는 성장에 영향을 미치지 않는 것으로 나타났다. 배양시간에 따른 한천농도는 15시간 이후 모두 분해되었으며 점도의 변화도 이와 유사한 것으로 나타났다. 또한 fed-batch 배양에서 0.8 g 한천을 2회 첨가하였으며 한천을 첨가한 후 agarase생산이 증가되는 것으로 나타났다. 한천올리고당의 성분분석을 한 결과 중합도가 6인 당이 확인되었다.

• The Plant Pathology Journal
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• 제16권4호
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• pp.236-241
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• 2000

A selective agar medium was developed and tested for the isolation of Acidovorax avenae subsp. avenae, the causal bacterial pathogen of bacterial brown stripe, from rice seeds. The new selective agar medium, designated sorbitol pyroglutamic acid agar (SPA) medium, contained 0.5 g of $K_2$HPO$_4$, 3.0 g of Na$_2$HPO$_4$, 2.0 g of D-sorbitol, 0.2 g of L-pyroglutamic acid, 10.0 $m\ell$ of tween 80, 40.0 mg of victoria blue B, 15.0 g of agar, 150.0 mg of ampicillin and 25.0 mg of vancomycin per litter. Colonies of A. avenae subsp. avenae on SPA medium were smooth, round, convex, shiny, blue and 1.5-2.0 mm in diameter 4 days after incubation at 28$^{\circ}C$. Blue colored colony having dark blue zone was typical type of A. avenae subsp. avenae colonies on the medium. Mean recovery of 8 isolates of A. avenae subsp. avenae on the selective SPA medium was 95.8% in comparison to that on KB medium. The saprophytic bacteria were reduced to 97.9% on SPA medium compared to those on KB medium. Most of other rice seedborne bacteria as well as reported pathogenic bacteria were failed to grow on SPA medium. This medium was highly selective for recovering A. avenae subsp. avenae from rice seed samples, and it could be used to enhance the recovery of this bacterium from rice seed samples, which may be contaminated with large numbers of competing microorganisms.

• 한국토양비료학회지
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• 제37권1호
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• pp.36-40
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• 2004

최근에는 친환경 농업을 위하여 사용되는 미생물 비료의 안정성 유지와 효능, 저장 및 운송 등에 대한 어려움 및 불편함을 극복하기 위해서 미생물을 담체에 고정화하여 생물비료로 사용하고 있다. 본 실험에서는 인산가용화 미생물인 Pantoea agglomerans를 alginate, agar 및 gelatin에 고정화시킨 후 tricalcium phosphate가 첨가된 액체 배지에서 배양하여 인산가용화능을 비교하였으며, 또한 alginate에 고정화된 균에 의한 인산가용화능을 경시적으로 조사하였다. 고정화를 위한 담체로 alginate나 agar를 사용하였을 때, 고정화된 P. agglomerans의 인산가용화능이 gelatin을 담체로 사용하였을 때보다 우수하였다. Alginate에 고정된 P. agglomerans가 접종된 처리구에는 배양 후 5일까지 유효인산의 농도가 크게 증가하였고 모든 처리 구에서 배지 안의 pH가 감소하였다.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1134-1141
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• 2004

A bacterial strain capable of hydrolyzing sulfate ester bonds in p-nitrophenyl sulfate and agar was isolated from the Southeast coast of Korea. The isolated strain (AS6330) is aerobic, Gram-negative, rod-shaped, and motile. Octadecanoic acid was the major cellular fatty acid in the isolate. An almost complete 16S rDNA sequence of the isolate was determined and the sequence similarity of the 16S rDNA with those of known Sphingomonas spp. was found to be at most $96.4\%$, implying that the isolate was a new Sphingomonas species. The organism was grown optimally at NaCl concentration of $1.5-3.5\%$. Optimum culture conditions were determined to be $30^{\circ}C$ and pH 7.0 for 48 h fermentation using a laboratory fermentor under constant culture conditions. Partially purified arylsulfatase through Q-Sepharose and phenyl­Sepharose chromatographies catalyzed hydrolysis of sulfate ester bonds in agar, and $97\%$ of sulfates in agar were removed after 4 h reaction at $45^{\circ}C$ and pH 7.0. The arylsulfatase from the isolated bacterium might be useful for the removal of sulfate groups in agar.