• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1549-1556
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• 2012

Endophytic fungi were isolated from roots of six halophytes in Suncheon Bay. The endophytic fungi of 35 species isolated from halophytes were identified by internal transcribed spacer (ITS) containing the ITS1, 5.8s, and ITS2 regions. All fungal strains were analyzed to diversity at the genus level. Fungal culture filtrates (FCF) of endophytic fungi were treated to Waito-c rice (WR) seedling for plant growth-promoting verification. It was confirmed that fungal strain Sj-2-2 provided plant growth promotion (PGP) to WR seedling. Then, PGP of Suaeda japonica was confirmed by treating culture filtrate of Sj-2-2. As a result, it was verified that culture filtrate of Sj-2-2 had more advanced PGP than positive control when treated to S. japonica. The secondary metabolites involved in culture filtrate of Sj-2-2 were identified by HPLC and GC-MS SIM analysis. The presence of physiologically bioactive gibberellins (GAs) and other inactive GAs in culture filtrate of Sj-2-2 was detected. The molecular analysis of sequences of Sj-2-2 showed the similarity to Penicillium sp. of 99% homology. The PGP of Sj-2-2 as well as symbiosis between endophytic fungi and halophytes growing naturally in salt marsh was confirmed. Sj-2-2 was identified as a new fungal strain producing GAs by molecular analysis of sequences. Consequently, the Sj-2-2 fungal strain was named as Penicillium sp. Sj-2-2. In this study, the diversity of endophytic fungi isolated from roots of halophytes in salt marsh and the PGP of a new gibberellin-producing fungal strain were confirmed.

• Asian-Australasian Journal of Animal Sciences
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• 제33권10호
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• pp.1610-1616
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• 2020

Objective: This study was to evaluate the effect of husbandry systems and strains on cecum microbial diversity of Jingyang chickens under the same dietary conditions. Methods: A total of 320 laying hens (body weight, 1.70±0.15 kg; 47 weeks old) were randomly allocated to one of the four treatments: i) Silver-feathered hens in enrichment cages (SEC) with an individual cage (70×60×75 cm), ii) Silver-feathered hens in free range (SFR) with the stocking density of 1.5 chickens per ten square meters, iii) Gold-feathered hens in enrichment cages (GEC), iv) Gold-feathered hens in free range (GFR). The experiment lasted 8 weeks and the cecum fecal samples were collected for 16S rDNA high throughput sequencing at the end of experiment. Results: i) The core microbiota was composed of Bacteroidetes (49% to 60%), Firmicutes (21% to 32%) and Proteobacteria (2% to 4%) at the phylum level. ii) The core bacteria were Bacteroides (26% to 31%), Rikenellaceae (9% to 16%), Parabacteroides (2% to 5%) and Lachnoclostridium (2% to 6%) at the genus level. iii) The indexes of operational taxonomic unit, Shannon, Simpson and observed species were all higher in SFR group than in SEC group while in GEC group than in GFR group, with SFR group showing the greatest diversity of cecum microorganisms among the four groups. iv) The clustering result was consistent with the strain classification, with a similar composition of cecum bacteria in the two strains of laying hens. Conclusion: The core microbiota were not altered by husbandry systems or strains. The free-range system increased the diversity of cecal microbes only for silver feathered hens. However, the cecum microbial composition was similar in two strain treatments under the same dietary conditions.

• Journal of Species Research
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• 제13권1호
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• pp.61-66
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• 2024

During an investigation of unrecorded prokaryotic species in Korea, six unrecorded bacterial strains were isolated from soil samples collected from Uljin-gun. Based on a similarity search using the 16S rRNA gene sequence of the isolated strains and the construction of the neighbor-joining phylogenetic tree, five strains were identified to the genus Pseudomonas of the family Pseudomonadaceae, while one strain was identified as a species belonging to the genus Paenibacillus of the family Paenibacillaceae. The details of these unreported species, including gram staining reaction, colony and cell morphology, basic biochemical characteristics, strain ID, and isolation source, are described in the description of the strains.

• 한국버섯학회지
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• 제20권4호
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• pp.249-253
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• 2022

버섯기생균은 버섯을 기주로 살아가면서 병을 일으킬 수 있는 진균이다. 야생버섯의 버섯기생균이 재배종에 병을 일으키는 병원균이 될 수 있다는 점에서 야생버섯의 버섯기생균 다양성을 연구하는 것은 버섯 산업에 중요하다. 그러나 국내에서는 야생버섯의 기생균 다양성에 관한 연구가 많지 않다. 본 연구에서는 버섯 다양성 조사 과정 중 발견한 버섯기생균을 분리하여 분자계통분석과 형태적 특성 조사를 통해 분석하였다. 그 결과 분리된 균주가 미기록종인 Sepedonium laevigatum 종으로 동정되었으므로, 이 균주의 배양적 특성과 미세구조의 특성을 조사하여 기재하였다.

• 식물병연구
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• 제13권3호
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• pp.137-144
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• 2007

거봉 포도나무에 혹병을 일으키는 A. vitis 균주간의 DNA 다양성 평가를 하기 위하여 12종류의 URP primer 적용 성을 조사한 결과 URP1F, URP2F, URP2R, URP4R, URP17R primer가 균주 간 DNA 다형성검정에 유용하였다. 국내외에서 분리한 59 A. vitis 균주를 URP-PCR 증폭하였던 바 균주간의 매우 다양한 PCR 다형성 밴드를 형성 하였으며 12 strain type으로 나눌 수 있었으며 거봉포도로부터 분리된 A. vitis 균주는 4 strain type의 비교적 단순한 유전적 다양성으로 나타났으나, 거봉이외의 다른 포도 품종이나 국외에서 도입된 A. vitis 균주는 8 strain type의 많은 유전적 다양성을 보여 거봉품종 유래 국내 균주와는 PCR 다형성 type에 있어 차이점을 보였다. URP-PCR 다형성 밴드를 집괴 분석하여 UPGMA dendrogram을 작성한 결과 7개의 대 Group으로 분류할 수 있었으며, 그룹 간에는 $62{\sim}100$%까지 다양한 유전적 유사성이 나타났다.

• 생명과학회지
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• 제19권5호
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• pp.684-687
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• 2009

핵과류 과수에 세균성구멍병을 일으키는 Xanthomonas arboricola pv. pruni는 집단의 다양성이 적은 것으로 알려지고 있다. 우리나라에서 분리된 X. arboricola pv. pruni의 유전적 특성을 조사하기 위하여 동일한 16S rDNA 염기서열을 갖는 X. arboricola pv. pruni의 type strain인 LMG852, 일본 균주 MAFF301420, 우리나라 균주 XWD1의 세 균주를 대상으로 세 개 유전자 부위의 DNA 염기서열과 RAPD 분석을 실시하였다. 그 결과 ITS와 glnA, atpD의 염기서열은 세 균주가 동일하였다. 그러나 756 염기로 구성된 atpD의 염기서열은 GenBank에 등록된 프랑스균주와 5곳에서 차이가 있었다. 40개의 random primer를 사용한 RAPD 결과는 우리나라와 일본균주는 동일한 밴드 패턴을 보이나 대표균주와는 다른 양상을 보였다. 이러한 사실은 우리나라와 일본의 X. arboricola pv. pruni의 개체군은 매우 가까워 유전적 다양성이 낮은 것으로 보이며 유럽균주와는 다른 기원과 전파 경로를 갖는 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.197-206
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• 2016

Listeria monocytogenes is a foodborne pathogen of considerable genetic diversity with varying pathogenicity. Initially, we found that the strain M7 was far less pathogenic than the strain Lm850658 though both are serovar 4a strains belonging to the lineage III. Comparative genomic approaches were then attempted to decipher the genetic basis that might govern the strain-dependent pathotypes. There are 2,761 coding sequences of 100% nucleotide identity between the two strains, accounting for 95.7% of the total genes in Lm850658 and 92.7% in M7. Lm850658 contains 33 specific genes, including a novel 20K prophage whereas strain M7 has 130 specific genes, including two large prophages (38K and 44K). To examine the roles of these specific prophages in pathogenicity, the 20K and 38K prophages were deleted from their respective strains. There were virtually no differences of pathogenicity between the deletion mutants and their parent strains, although some putative virulent factors like VirB4 are present in the 20K region or holin-lysin in the 38K region. In silico PCR analysis of 29 listeria genomes show that only strain SLCC2540 has the same 18 bp integration hotspot as Lm850658, whereas the sequence identity of their 20K prophages is very low (21.3%). The 38K and 44K prophages are located in two other different hotspots and are conserved in low virulent strains M7, HCC23, and L99. In conclusion, the 20K and 38K prophages of L. monocytogenes serovar 4a strains Lm850658 and M7 are not related to virulence but contribute to genetic diversity.

• Journal of Species Research
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• 제10권2호
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• pp.99-116
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• 2021

In 2018, as a subset study to discover indigenous prokaryotic species in Korea, a total of 18 unreported bacterial strains were discovered. From the high 16S rRNA gene sequence similarity (>98.8%) and formation of a robust phylogenetic clade, it was determined that each strain belonged an independent and predefined bacterial species. There were no official report that these 18 species were previously described in Korea; therefore, one strain of Williamsia, one strain of Rhodococcus, three strains of Microbacterium, three strains of Agromyces, one strain of Arthrobacter, one strain of Paeniglutamicibacter, one strain of Pseudarthrobacter, one strain of Nocardioides, one strain of Fibrella, one strain of Hymenobacter, one strain of Deinococcus, two strains of Fictibacillus, and one strain of Paenibacillus are described as unreported bacterial species in Korea. Gram reaction, basic biochemical characteristics, and colony and cell morphologies are described in the species description section.

• 한국버섯학회지
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• 제12권1호
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• pp.41-51
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• 2014

${\beta}$-glucan 함량이 높다고 알려진 꽃송이버섯의 농가재배 활성화를 위하여 푸른곰팡이 내성균주를 선발하고자 푸른곰팡이 대치배양에 의한 꽃송이버섯 균사생장 특성을 확인하였으며, 또한 생장이 우수한 신품종을 개발하고자 교잡육종 균주에 대한 유전 다양성을 분석하였다. 먼저 푸른곰팡이 대치배양에 의한 꽃송이버섯 균사의 생장 특성을 확인한 결과, 6951 (T. viride) 균주에서는 대치선을 형성한 후 별다른 변화를 보이지 않았고, 6952 (T. spp.) 균주에서는 대치선을 형성한 다음 보다 많은 포자를 형성하는 것이 관찰되었다. 그러나 6426 (T. harzianum) 균주에서는 꽃송이버섯 균사가 생장하고 있던 부분까지 모두 덮어버리는 것이 확인되었다. 그 중 특이하게도 구례에서 채집선발한 균주인 JF02-06 균주에서는 다른 균주에 비해 푸른곰팡이 포자가 형성되지 않는 것을 확인되어 다소 푸른곰팡이에 대한 저항성을 갖는 것으로 사료되었다. 전남 산림자원연구소에서 보유 중인 균주 중 생장 및 자실체 발생이 우수한 모균주를 선발하여 교잡을 실시하여 생장특성을 조사한 결과, 미송톱밥배지에서 JF02-47, 49, 50 균주의 균사생장량이 우수한 것으로 확인되었다. 이러한 교잡육종 균주의 유전 다양성을 분석하기 위하여 ITS1, 5.8S와 ITS4 영역에 대한 염기서열을 분석한 결과 Genebank에 등록된 다른 꽃송이버섯 균주와 높은 유의성을 갖는 것으로 확인되었다. 이러한 꽃송이버섯의 포자 및 균사를 현미경으로 관찰하여 생장 특성을 확인한 결과, 포자의 크기는 장경 $6{\mu}m$, 단경 $5{\mu}m$의 물방울 모양으로 확인되었고, 균사에서 3가지 형태의 꺽쇠가 관찰되었다. 균사의 폭은 $3{\mu}m$이며 꽃송이버섯 균사의 특징으로는 약 50% 정도 꺽쇠에서 균사가 뻗어나가는 특성을 갖고 있음이 확인되었다. 균사의 생장 속도는 $0.507{\mu}m/min$이며, 2차 균사는 $0.082{\mu}m/min$의 속도로 생장하다가 모균사와 평행을 이루는 시점에서는 모균사의 생장속도와 유사한 속도로 생장하였다. 꺽쇠발생은 약 5시간 동안 균사 내부 전해질의 이동이 관찰된 후 작은 꺽쇠를 형성하였다. 약 3시간 후 격막이 형성되기 시작하였으며, 그로부터 2시간 후 최종적으로 완성되었다. 이러한 특성을 갖는 꽃송이버섯의 푸른곰팡이 저항성을 확인하고, 교잡균주의 유전 다양성 및 균사의 생장 특성을 확인하여 꽃송이버섯에 대한 기초적인 이해를 높이고, 더 나아가 버섯산업 발전에 이바지하고자 한다.

• Ocean and Polar Research
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• 제26권1호
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• pp.51-58
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• 2004

We isolated and identified culturable Arctic bacteria that had inhabited soils around the Korean Arctic Research Station Dasan located at Ny-Alsund, Svalbard, Norway $(79^{\circ}N,\;12^{\circ}E)$. The collected soils were diluted in distilled water; the diluted soil-water was spread on 3M petri-films at Dasan Station. The petri-films were transported to the laboratory at KORDI, and cultured at $4^{\circ}C$. Colonies grown on the petri-films were subsequently cultured on nutrient agar plates at $4^{\circ}C$ every 7 days. The pure colonies were inoculated into nutrient liquid media, genomic DNA was extracted, and phylogenetic analysis was performed on the basis of 165 rDNA sequences. A total of 227 strains of bacteria were isolated. Among them, 16S rDNA sequences of 185 strains were identical with those of known strains isolated in this study, and 42 strains were finally identified. Phylogenetic analysis using 16S rDNA indicated that the 30 strains belonged to Pseudomonas, 7 strains to Arthrobacter, two strains to Flavobacterium, and the remaining to Achromobacter, Pedobacter, and Psychrobacter. Among the 42 strains, 14 bacteria produced protease: they were 6 strains of Pseudomonax, 4 strains of Arthrobater, an Achromobacter strain, 2 strains of Flavobacterium, and a Pedohacter strain. We expect these Arctic bacteria can be used for screening to develop new industrial enzymes that are active at low temperatures.