• 한국응용과학기술학회지
• /
• 제37권6호
• /
• pp.1489-1495
• /
• 2020

Gotjawal, Jeju Island, Korea is a lava-formed forest with low soil content that is unique in the world. Around 6 percent of the Jeju Iand is classified as a lava-based specific forest. The forest has been gradually disappearing during the last several decades, with approximately one half having been destroyed. Our study undertakes a detailed analysis of the landscape of the lava subsidence, and describes the fungi, vegetation, and soils of Cheongsu Gotjawal. Soil samples from the Gotjawal were collected, and soil analyses as well as pyrosequencing of the internal transcribed spacer gene for fungal communities were performed. Soil fungal communities are represented by Discisedars, Fusarium, Pleochaeta, and Fuscoporia genera. Endemic vegetation of the Gotjawal includes the plants Pleris critical, Machilus japonica, Quercus glauca, Arachniodes aristata, and Neocheiropteris ensata. Results of soil analysis indicate sandy loam with 31.70% organic matter, and 1.36 mg/kg of total nitrogen. This fundamental information can help understand the invaluable and unique nature of Cheongsu Gotjawal, and the necessity for more studies on Gotjawal.

• 미생물학회지
• /
• 제52권1호
• /
• pp.32-39
• /
• 2016

독도에 자생하는 번행초의 뿌리로부터 순수 분리하여 형태적으로 상이한 17개의 내생균류를 선별하였다. 또한 분리된 균류들에 대하여 각각의 염농도와 pH 농도 구배에 따라 생장 시험을 확인하였다. 내생균류에 대해 각각 난장이벼의 유묘에 식물생장활성시험을 진행하였고, 그 결과 YH103 균주가 가장 높은 활성을 나타내었다. 계통분석은 Maximum likelihood 방법을 활용하여 결합된 ITS영역, beta-tubulin 및 calmodulin 유전자 염기서열을 분석하여 분리된 균주의 유연관계를 분석하였다. YH103 균주의 배양여과액을 HPLC와 GC/MS SIM을 이용하여 분석한 결과 식물호르몬인 지베렐린 $GA_4$, $GA_7$, $GA_8$ 및 $GA_{19}$가 확인되었다. 최종적으로 YH103 균주의 형태학적 관찰 및 결합된 유전자 염기서열의 분자적 분석을 통해 GA를 생산하는 새로운 Aspergillus tubingensis로 동정되었다.

• Mycobiology
• /
• 제44권4호
• /
• pp.237-247
• /
• 2016

Aspergillus (Trichocomaceae, Eurotiales, and Ascomycota) is a genus of well-defined asexual spore-forming fungi that produce valuable compounds such as secondary metabolites and enzymes; however, some species are also responsible for diseases in plants and animals, including humans. To date, 26 Aspergillus species have been reported in Korea, with most species located in terrestrial environments. In our study, Aspergillus species were isolated from mudflats and sea sand along the western and southern coasts of Korea. A total of 84 strains were isolated and identified as 17 Aspergillus species in 11 sections on the basis of both morphological characteristics and sequence analysis of the calmodulin gene (CaM) locus. Commonly isolated species were A. fumigatus (26 strains), A. sydowii (14 strains), and A. terreus (10 strains). The diversity of Aspergillus species isolated from mudflats (13 species) was higher than the diversity of those from sea sand (five species). Four identified species-A. caesiellus, A. montenegroi, A. rhizopodus, and A. tabacinus-are in the first records in Korea. Here, we provide detailed descriptions of the morphological characteristics of these four species.

• 한국식품위생안전성학회지
• /
• 제35권4호
• /
• pp.375-381
• /
• 2020

본 연구에서는 국내 유통중인 가정간편식 샤브샤브 밀키트를 원료별(쇠고기, 숙주, 쌈추, 새송이버섯, 배추, 단호박)로 구분하여 미생물 오염도를 알아보기 위해 일반세균수(total aerobic bacteria), 대장균군(coliform)/대장균(E. coli), 효모 및 진균류(fungi), 황색포도상구균(S. aureus), 및 바실러스세레우스(B. cereus)에 대한 정량적 분석을 실시하였다. 아울러, 살모넬라(Salmonella spp.)와 리스테리아 모노사이토제네스(L. monocytogenes)에 대한 정성적 분석을 실시하였다. 샤브샤브 밀키트 원료의 일반세균수(총균수)는 3.98-6.50 log CFU/g로 검출되었다. 특히, 쇠고기의 경우 6 log CFU/g 이상의 균이 검출되었으며 숙주, 단호박, 배추의 경우 5 log CFU/g 이상의 균이 검출되었다. 진균류 (곰팡이/효모)의 오염도는 2.78-3.52 log CFU/g 수준으로 검출되었다. 대장균군은 일반세균수와 마찬가지로 쇠고기에서 3.28 log CFU/g으로 가장 높게 검출되었으며 기타 신선야채류의 경우 2 log CFU/g 수준으로 검출되었다. 대장균은 6가지 원료 모두에서 검출되지 않았다. S. aureus는 쇠고기와 쌈추를 제외한 숙주, 배추, 새송이버섯, 단호박에서 1.33-1.71 log CFU/g의 수준으로 검출되었다. B. cereus는 쌈추를 제외한 모든 원료에서 1.15-2.01 log CFU/g의 수준으로 검출되었다. L. monocytogenes는 새송이버섯을 제외하곤 모든 원료에서 25-50%의 양성검출을 보였고 Salmonella는 모든 원료에서 음성으로 나타났다. 본 연구 결과의 종합적 분석시, 쇠고기 원료에서 일반세균수와 대장균군 기준치를 초과하였고 황색포도상구균과 바실러스세레우스는 대부분의 원료에서 식품안전을 위협할 만한 위험한 수준은 아니었으나 검출되었고 저온성식중독균인 리스테리아모노사이토제네스 역시 일부 원료에서 양성을 보였기 때문에 본 제품의 원료별 생산단계에서의 살균·소독의 적절한 공정과 섭취시 충분한 열처리를 통해 잔존미생물을 사멸하는 것이 긴요하다. 또한 조리기구 및 조리 종사원 손에 의해 최종 식품을 공정하면서 미생물이 전파될 가능성이 있으므로 최종 식품의 안전성을 확보하기 위해 오염된 접촉면에 의한 교차오염을 최소화하며, 개인위생수준의 개선, 조리기기의 분리사용과 세척 및 소독을 통한 조리기기의 청결유지가 무엇보다도 중요하다. 아울러 본 연구의 미생물오염수준 자료는 가정간편식밀키트의 미생물위해평가(Microbial Risk Assessment)의 기초자료로 활용될 수 있을 것으로 사료된다.

• 한국미생물·생명공학회지
• /
• 제50권2호
• /
• pp.255-269
• /
• 2022

Actinomycetes isolated from marine habitats represent a promising source of bioactive substances. Here, we report on the isolation, identification, productivity enhancement and application of the bioactive compounds of Streptomyces qinglanensis H4. Eighteen marine actinomycetes were isolated and tested for resistance to seven bacterial diseases. Using 16S rRNA sequencing analysis (GenBank accession number MW563772), the most powerful isolate was identified as S. qinglanensis. Although the strain produced active compound(s) against a number of Gram-negative and Gram-positive bacteria, it failed to inhibit pathogenic fungi. The obtained inhibition zones were 22.0 ± 1.5, 20.0 ± 1, 16.0 ± 1, 12.0 ± 1, 22.0 ± 1 and 24.0 ± 1 mm against Bacillus subtilis ATCC 6633, Escherichia coli ATCC 19404, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231 and Staphylococcus aureus ATCC6538, respectively. To maximize bioactive compound synthesis, the Plackett-Burman design was used. The productivity increased up to 0.93-fold, when S. qinglanensis was grown in optimized medium composed of: (g/l) starch 30; KNO₃ 0.5; K₂HPO₄ 0.25; MgSO₄ 0.25; FeSO₄·7H₂O, 0.01; sea water concentration (%) 100; pH 8.0, and an incubation period of 9 days. Moreover, the anticancer activity of S. qinglanensis was tested against two different cell lines: HepG2 and CACO. The inhibition activities were 42.96 and 57.14%, respectively. Our findings suggest that the marine S. qinglanensis strain, which grows well on tailored medium, might be a source of bioactive substances for healthcare companies.

• 셀메드
• /
• 제6권4호
• /
• pp.22.1-22.19
• /
• 2016

The biologically active compounds derived from different natural organisms such as animals, plants, and microorganisms like algae, fungi, bacteria and merine organisms. These natural compounds possess diverse biological activities like anthelmintic, antibacterial, antifungal, antimalarial, antiprotozoal, antituberculosis, and antiviral activities. These biological active compounds were acted by variety of molecular targets and thus may potentially contribute to several pharmacological classes. The synthesis of natural products and their analogues provides effect of structural modifications on the parent compounds which may be useful in the discovery of potential new drug molecules with different biological activities. Natural organisms have developed complex chemical defense systems by repelling or killing predators, such as insects, microorganisms, animals etc. These defense systems have the ability to produce large numbers of diverse compounds which can be used as new drugs. Thus, research on natural products for novel therapeutic agents with broad spectrum activities and will continue to provide important new drug molecules.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
• /
• pp.174-174
• /
• 1998

Twelve different derivatives were synthesised from chitin/chitosan[1, 2, 3]. Their structures have been determined by different physical methods. The bioassay screening on antifungal and antibacterial activities of all these compounds showed that most of them had significant activity and they can inhibite the growth of some fungi and bacterias : E. coli, S. pyogenes, F. oxysporum, P. oryzae, that caused the spoilage of fresh fruits and foods. Furthermore, all of these compounds are non-toxic (LD$\_$50/>50g/kg) and can be applied for food preservation.

• 미생물학회지
• /
• 제41권3호
• /
• pp.157-163
• /
• 2005

요각류 Paracyclopina nana Acetate Kinase를 클로닝하였다. 전체 open reading frame은 1,200 bp이었으며, poly(A) signal sequence가 ORF에 내재되어 있었다. 분자계통학적 분석결과 P. nana acetate kinase 유전자는 진핵생물계 곰팡이류인 Aspegillus와 같은 branch를 형성하였고, P. nana acetate kinase가 다른 원핵미생물들의 acetate kinase와는 구별되며 fungi와 같은 branch에 존재하는 것을 확인하였다. 또한, E. coli를 이용하여 원핵세포 발현벡터를 이용한 단백질 발현 유도를 통하여 P. nana acetate kinase 단백질 분자량이 약 50 kDa에 이르는 것을 확인하였다. 이 자료는 본 요각류와 다른 생물의 acetate kinase 단백질의 생화학적 특성비교에 유용하게 쓰이리라 사료된다.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2006년도 추계 학술발표회 발표논문집
• /
• pp.285-289
• /
• 2006

In screening of algicidal bacteria, we isolated a marine bacterium which had potent algicidal effects on harmful algal bloom (HAB) species. This organism was identified as a strain very close to Bacillus subtilisby 16S rRNA gene sequencing. This bacterium, Bacillus sp. SY-1, produces very active algicidal compounds against the harmful dinoflagellate Cochlodinium polykrikoides. We isolated three algicidal compounds (MS 1056, 1070, 1084) and identified them by amino acid analyses, fast atom bombardment mass spectrometry (FAB-MS), infrared spectroscopy (IR), $^1H$, $^{13}C$, and extensive two-dimensional nuclear magnetic resonance (2D NMR) techniques including $^1H-^{15}N$ HMBC analysis. One of them, MS 1056, contains a b-amino acid residue with an alkyl side chain of $C_{15}$. MS 1056, 1070, and 1084 showed algicidal activities against C. polykrikoides with an $LC_{50}$ (6 hrs) of 2.3, 0.8, $0.6\;{\mu}g/ml$, respectively. These compounds also showed significant algicidal activities against other harmful dinoflagellates and raphidophytes. In contrast, MS 1084 showed no significant growth inhibition against various organisms coexisting with HAB species in natural environments, including bacteria, eukaryotic microalgae, and cyanobacteria, although it inhibited growth of some fungi and yeasts. These observations imply that algicidal bacterium Bacillus sp. SY-1 and its algicidal compounds could play an important role in regulating the onset and development of HABs in the natural environments.

• Journal of Microbiology and Biotechnology
• /
• 제24권11호
• /
• pp.1559-1565
• /
• 2014

Cellulase and xylanase are main hydrolysis enzymes for the degradation of cellulosic and hemicellulosic biomass, respectively. In this study, our aim was to develop and test the efficacy of a rapid, high-throughput method to screen hydrolytic-enzyme-producing microbes. To accomplish this, we modified the 3,5-dinitrosalicylic acid (DNS) method for microwell plate-based screening. Targeted microbial samples were initially cultured on agar plates with both cellulose and xylan as substrates. Then, isolated colonies were subcultured in broth media containing yeast extract and either cellulose or xylan. The supernatants of the culture broth were tested with our modified DNS screening method in a 96-microwell plate, with a $200{\mu}l$ total reaction volume. In addition, the stability and reliability of glucose and xylose standards, which were used to determine the enzymatic activity, were studied at $100^{\circ}C$ for different time intervals in a dry oven. It was concluded that the minimum incubation time required for stable color development of the standard solution is 20 min. With this technique, we successfully screened 21 and 31 cellulase- and xylanase-producing strains, respectively, in a single experimental trial. Among the identified strains, 19 showed both cellulose and xylan hydrolyzing activities. These microbes can be applied to bioethanol production from cellulosic and hemicellulosic biomass.