• 미생물학회지
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• 제27권1호
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• pp.21-26
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• 1989

한국산 Klebsiella pnelµnoniae KNFl의 chromosomal DNA를 Hind III로 부분소화하고 pBR 322도 같은 효소로 완전소화했다. 소화된 pBR 322 의 5'- 말단연산기를 제거하여 두 DNA 표품을 ligation 한 후 E. coli K060 으로 transformation 하 였다. 이러한 transformants중 N-free 한천배지에서 자라는 단일 colony을을 얻었으며, 이들은 모두 ampicillin에 대해 저 항성을 가지고 있었고 tetracycline에 대해 저항성이 없었으며 cunng 되였을 때는 질소고정능을 잃었다. 이런 사실로부터 이 transformants가 K. pneumoniae의 질소고정능 유전자을 포함하는 recombinant plasmid를 가지고 있음을 확인할 수 있었다. 이들 transformants의 nitrogenase 역가는 K. pneumoniae KNF 1보다 더 높았다.

• 생명과학회지
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• 제8권6호
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• pp.623-626
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• 1998

포인세티아식물체의 줄기조직을 이용한 재분화조건을 확립하였다. MS배지에 종류 및 농도별 식물성장 조절제를 첨가하여 포인세티아의 잎, 줄기, 엽병조직으로부터의 배구조의 발생을 조사하였다. 잎과 엽병조직에서는 callus의 형성은 실험조건에서 매우 활발하였으나 배구조로의 발달은 전혀 이루어지지 않았다. 줄기조직의 경우에서는 1.5 mg/L의 BA가 첨가되는 경우 6-8주 정도의 경과 후 엽초의 발생이 관찰되었다. 이들을 식물생장조절제를 무첨가한 MS고체배지로 이동시 뿌리의 발달이 관찰되었다.

• Journal of Microbiology
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• 제39권2호
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• pp.146-148
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• 2001

Lactobacillus crispatus ATCC 33820 and L. gasseri ATCC 33323 were grown in MRS broth (pH 6.5) at 37$^{\circ}C$ for 24 h and the antibacterial activities of cell free culture supernatants were determined by the agar well diffusion method. The culture supernatants were inhibitory to Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Pediococcus acidilacticii, and Lactobacillus helveticus. The supernatants did not show any lysozyme activity. Addition of catalase did not affect the antibacterial activities of the supernatants. The antibacterial substances were heat stable (100$^{\circ}C$ for 60 min) and sensitive to proteases.

• 미생물학회지
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• 제39권1호
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• pp.56-61
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• 2003

본 실험의 목적은 Gram 양성균 뿐만 아니라 Gram음성세균에 대한 넓은 항균활성 및 내산성 그리고 항생제 내성을 갖고 있는 유용한 probiotic 후보균주를 선발하여 어류의 세균성 질병 예방 흑은 치료를 함으로써 양식산업의 효율성을 증대시키고자 한다. 20균주의 유산균을 김치, 양식 넙치의 장 그리고 각종 젓갈류 중에서 분리하여 어류 병원성 세균에 대한 항균능을 MRS agar상에서 agar spotted method에 의해 조사하여 Vibrio anguillarum, Edwardsiella tarda 그리고 streptococcus sp.에 대해 항균활성 이 있는 7균주를 1차 선발 하고 이들중 항균스펙트럼 이 넓은 BK19를 최종선발하여 동정한 결과 Lactobacillus sakei BKl9로 나타났다. L. sakei BK19의 cell free supernatant를 pH 중화 및 catalase 처리한 후 어병세균에 대하여 항균활성을 확인하였다. L. sakei BK19 supernatant의 V.anguillarum 및 V.alginolyticus에 대한 항균성 기작은 주사전자현미경 관찰을 통하여 확인하였고 세포벽을 붕괴 시킴으로써 성장을 저해하고 사멸시키는 것으로 확인되었다.

• Reproductive and Developmental Biology
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• 제36권3호
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• pp.163-166
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• 2012

This study was conducted to determine the relationship between elapsed time after semen preservation on the changes of bacteria and semen quality. Semen was diluted with BTS(Beltsville Thawing Solution) extender without antibiotic for 7 days and sperm parameter and fertility were measured. Sperm motility was measured by CASA and total bacteria number was counted after 22~24 hr incubation from counting agar plate in which sperm dilute to $10{\sim}10^6$ in 0.9% saline solution and inoculate to agar. Acrosomal integrity was measured by Chlortetracycline (CTC) staining. CTC patterns were uniform fluorescence over the whole head (pattern F), characteristic of incapacitated acrosome-intact spermatozoa; fluorescence-free band in the post-acrosomal region (pattern B), characteristic of capacitated acrosome-intact spermatozoa; and almost no fluorescence over the whole head except for a thin band in the equatorial segment (pattern AR), characteristic of acrosome reacted spermatozoa. Total number of bacteria was significantly increased (p<0.0001) 3 days after preservation. Sperm motility, viability, and morphological abnormality on elapsed time after preservation were lower from 5 ($77.24{\pm}6.47$, p<0.001) and 7 days ($77.24{\pm}6.47$, p<0.001) after preservation compared to 1 ($15.71{\pm}7.18$) and 3 days($18.39{\pm}7.22$) after preservation, respectively. Sperm viability was significantly lower ($53.25{\pm}35.03$, p<0.0001) at 7 days after preservation. Morphological abnormality of sperm was lower (p<0.001) at 1 ($15.71{\pm}7.18$) and 3 ($18.39{\pm}7.22$) days compared to 5 ($21.84{\pm}7.91$) and 7 ($22.59{\pm}9.93$) days after preservation. Acrosomal integrity and capacitation rate (pattern F) were significantly lower (p<0.001) from 5 days after preservation. Based on the data we obtained from this study suggested that semen preserved more than 5 days without antibiotic would not recommend use for artificial insemination.

• 한국미생물·생명공학회지
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• 제46권3호
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• pp.225-233
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• 2018

In this exploratory study, eight types of microalgae from different phyla (Chlamydomonas reinhardtii, Chlorella species, Haematococcus pluvialis, Porphyridium purpureum, Porphyridium cruentum, Isochrysis species, Isochrysis galbana, and Pavlova lutheri) were tested for their antibacterial activities against eight target pathogenic bacterial strains. The agar well diffusion method and broth micro dilution assay were conducted to estimate the antibacterial activity. Microalgae cell-free supernatants, exopolysaccharides (EPS), water, and organic solvent extracts were used for inhibition analysis. EPS extracted from P. lutheri showed activity against Bacillus subtilis and Pseudomonas aeruginosa. Inhibition zone diameters of 14-20 mm were recorded on agar plates, while the minimum inhibitory concentrations in the broth micro dilution assay were $0.39-25mg\;ml^{-1}$. During this study, haptophyte microalgae, Isochrysis species, and P. lutheri extracts showed the highest activity against most of the tested pathogenic bacterial strains, while most of the extracts were active against the important foodborne pathogen P. aeruginosa. This study showed promising results regarding important microalgae phyla, which will further aid research related to extracts and exploitation of bioactive metabolic compounds in the food and pharmaceutical industries.

• Journal of Applied Biological Chemistry
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• 제49권4호
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• pp.165-170
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• 2006

The antifungal activity of crude methanolic extract and fractions from Yucca smalliana Fern. leaves, roots and flowers were investigated in vitro against a panel of plant pathogenic fungi. The minimal inhibitory concentration(MIC) was determined by an agar dilution method. Preliminary liquid culture and agar plate assays showed that the growth of Fu sarium oxysporum, Phytophthora capsici, Rhizoctonia solani and Botrytis cinerea were inhibited by Y. smalliana extracts. The extracts from flowers and leaves showed antifungal activity of 64.0% and 34.0% against F. oxysporum, 66.0% and 62.0% against P. capsici, and 27.0% and 41.0% against B. cinerea, respectively. The methanolic extract from Y. smallina leaves in distilled water was fractionated using solvents of increasing polarity: hexane, ethyl acetate and butanol. These fractions had a broad spectrum of antifungal activity, found to reside entirely in the butanol and aqueous fraction. The aqueous fraction showed inhibition rate of 60.0, 67.8, 84.6 and 58.3% against F. oxysporum, R. solani, C. gloeosporioides, and B. cinerea, respectively, and the butganol fracgtion showed 36.0, 46.0, 66.1 and 58.3%, respectively. Phenolics(e.g. flavonoids, steroids and terpenoids) were observed in the thin layer profile of the different fractions. Leave extract showed a prominent antioxidant activity totally scavenging the free radical of DPPH at a concentration of 1 mg/ml.

• Parasites, Hosts and Diseases
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• 제55권3호
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• pp.233-238
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• 2017

Pathogenic Naegleria fowleri, Acanthamoeba castellanii, and Acanthamoeba polyphaga, are distributed worldwide. They are causative agents of primary amoebic meningoencephalitis or acanthamoebic keratitis in humans, respectively. Trophozoites encyst in unfavorable environments, such as exhausted food supply and desiccation. Until recently, the method of N. fowleri encystation used solid non-nutrient agar medium supplemented with heat-inactivated Escherichia coli; however, for the amoebic encystment of Acanthamoeba spp., a defined, slightly modified liquid media is used. In this study, in order to generate pure N. fowleri cysts, a liquid encystment medium (buffer 1) modified from Page's amoeba saline was applied for encystation of N. fowleri. N. fowleri cysts were well induced after 24 hr with the above defined liquid encystment medium (buffer 1). This was confirmed by observation of a high expression of differential mRNA of nfa1 and actin genes in trophozoites. Thus, this liquid medium can replace the earlier non-nutrient agar medium for obtaining pure N. fowleri cysts. In addition, for cyst formation of Acanthamoeba spp., buffer 2 (adjusted to pH 9.0) was the more efficient medium. To summarize, these liquid encystment media may be useful for further studies which require axenic and pure amoebic cysts.

• 식물조직배양학회지
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• 제24권6호
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• pp.369-374
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• 1997

카네이션의 종묘 급속증식 기술 및 형질전환 연구의 기초 연구로서 체세포배발생 조직배양 방법을 개발하고자 수행되었다. 'Desio' 카네이션의 20 mm 이하의 미숙화뢰를 2,4-D가 1 ㎎/L 함유된 MS 기본배지에서 배양하면 배발생 캘러스가 5-l0%의 효율로 유도되었으나, 줄기 정단분열조직, 잎, 절간조직과 20 ㎜ 이상의 화뢰에서는 비배발생 캘러스만이 형성되었다. 동일한 배양방법을 16품종의 절화용 카네이션에 적용한 결과, 7품종에서 배발생 캘러스를 유도할 수 있었다. 일부 배발생 캘러스 세포주는 120주 이상 배발생능 상실 없이 계대배양을 통해 증식할 수 있었으며, 액체 진탕 배양을 통해 배발생 세포괴 상태로 급속 증식하는 배양체가 획득되었다. 배발생 캘러스 또는 액체배양 배발생 세포괴를 호르몬이 포함되지 않은 MS 한천배지에 이식하며 2-3주내에 체세포배 발생을 통하여 식물체가 재분화되었다. 토양이식된 식물체는 정상적으로 생장하여 20주 후 개화하였다.

• 한국유기농업학회지
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• 제23권2호
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• pp.301-309
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• 2015

본 연구에서는 무농약 산머루 즙의 양을 각각 50 g, 100 g, 150 g, 200 g 수준으로 다르게 첨가하여 양갱을 제조하고 색도, 당도, 기계적 조직감, 관능평가를 조사하였다. 무농약 산머루 양갱의 색도는 명도(L)값과 황색도(b)값이 무농약 산머루 즙의 첨가농도가 증가할수록 감소하였으나, 반대로 적색도(a)값은 증가하는 경향을 나타내었다. 당도는 대조군이 2.31 Brix로 가장 낮게 나타났으며 무농약 산머루 즙의 첨가량이 증가할수록 당도가 점차 높아져 유의적인 차이를 보였다. 기계적 조직감은 무농약 산머루 즙의 첨가량이 증가할수록 경도는 증가하는 경향을 나타냈지만, 탄력성, 응집성, 점착성, 씹힘성 등은 모두 감소하는 경향을 나타내었다. 관능검사 결과는 색, 향, 맛 등의 전체적 선호도에서 무농약 산머루 즙 150 g 첨가군이 가장 높은 점수를 얻었다.