• 한국멀티미디어학회논문지
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• 제11권12호
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• pp.1697-1705
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• 2008

Several studies made for wireless mesh networks aim to optimize the capacity for wireless networks. Aside from protocol improvements, researches were also done on the physical layer particularly on modulation techniques and antenna efficiency schemes. This paper is concerned with the capacity improvements derived from using spatial diversity with smart adaptive array antennas. The use of spatial diversity, which has been widely proposed for use in cellular networks in order to lessen frequency re-use, can be used in mesh networks both to minimize co-channel interference (CCI) and enable multiple transmissions. This paper aims to study the capacity region and bounds in using smart antennas for single-channel multi-radio systems in relation to the number of spatial diversity or sectors as defined by the beam angle $\beta$.

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.1-10
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• 2015

The bacterial diversity of 10 marine sponges belonging to the species Cliona celata, an unidentified Cliona species, Haliclona cinerea, Halichondria okadai, Hymeniacidon sinapium, Lissodendoryx isodictyalis, Penares incrustans, Spirastrella abata, and Spirastrella panis collected from Jeju Island and Chuja Island was investigated using amplicon pyrosequencing of the 16S rRNA genes. The microbial diversity of these sponges has as of yet rarely or never been investigated. All sponges, except Cliona celata, Lissodendoryx isodictyalis, and Penares incrustans, showed simple bacterial diversity, in which one or two bacterial OTUs occupied more than 50% of the pyrosequencing reads and their OTU rank abundance curves saturated quickly. Most of the predominant OTUs belonged to Alpha-, Beta-, or Gammaproteobacteria. Some of the OTUs from the sponges with low diversity were distantly (88%~89%) or moderately (93%~97%) related to known sequences in the GenBank nucleotide database. Phylogenetic analysis showed that many of the representative sequences of the OTUs were related to the sequences originating from sponges and corals, and formed sponge-specific or -related clades. The marine sponges investigated herein harbored unexplored bacterial diversity, and further studies should be done to understand the microbes present in sponges.

• Mycobiology
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• 제47권1호
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• pp.76-86
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• 2019

Scab disease caused by Venturia nashicola is of agroeconomic importance in cultivation of Asian pear. However, little is known about the degree of genetic diversity in the populations of this pathogen. In this study, we collected 55 isolates from pear scab lesions in 13 major cultivation areas in Korea and examined the diversity using sequences of internal transcribed spacer (ITS) region, ${\beta}$-tubulin (TUB2), and translation elongation factor-$1{\alpha}$ ($TEF-1{\alpha}$) genes as molecular markers. Despite a low level of overall sequence variation, we found three distinctive subgroups from phylogenetic analysis of combined ITS, TUB2, and $TEF-1{\alpha}$ sequences. Among the three subgroups, subgroup 1 (60% of isolates collected) was predominant compared to subgroup 2 (23.6%) or subgroup 3 (16.4%) and was distributed throughout Korea. To understand the genetic diversity among the subgroups, RAPD analysis was performed. The isolates yielded highly diverse amplicon patterns and none of the defined subgroups within the dendrogram were supported by bootstrap values greater than 30%. Moreover, there is no significant correlation between the geographical distribution and the subgroups defined by molecular phylogeny. Our data suggest a low level of genetic diversification among the populations of V. nashicola in Korea.

• 한국환경농학회지
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• 제40권3호
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• pp.194-202
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• 2021

BACKGROUND: Towards achievement of sustainable agriculture, using microbial inoculants may present promising alternatives without adverse environmental effects; however, there are challenging issues that should be addressed in terms of effectiveness and ecology. Viability and stability of the bacterial inoculants would be one of the major issues in effectiveness of microbial pesticide uses, and the changes within the indigenous microbial communities by the inoculants would be an important factor influencing soil ecology. Here we investigated the stability of the introduced bacterial strains in the soils planted with barley and its effect on the diversity shifts of the rhizosphere soil bacteria. METHODS AND RESULTS: Two different types of bacterial strains of Bacillus thuringiensis and Shewanella oneidensis MR-1 were inoculated to the soils planted with barley. To monitor the stability of the inoculated bacterial strains, genes specific to the strains (XRE and mtrA) were quantified by qPCR. In addition, bacterial community analyses were performed using v3-v4 regions of 16S rRNA gene sequences from the barley rhizosphere soils, which were analyzed using Illumina MiSeq system and Mothur. Alpha- and beta-diversity analyses indicated that the inoculated rhizosphere soils were grouped apart from the uninoculated soil, and plant growth also may have affected the soil bacterial diversity. CONCLUSION: Regardless of the survival of the introduced non-native microbes, non-indigenous bacteria may influence the soil microbial community and diversity.

• 한국해양생명과학회지
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• 제8권1호
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• pp.43-49
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• 2023

본 연구에서는 남극 로스해 연안에 서식하는 아델리펭귄(Pygoscelis adeliae)과 황제펭귄(Aptenodytes forsteri)의 분변 시료를 기반으로 펭귄 장내 미생물 메타지놈 연구를 수행하였다. Taxonomy 분석 결과, 아델리펭귄과 황제펭귄의 장내 미생물에는 주로 7개의 문(phylum), 18개의 과(family)가 존재하는 것으로 나타났다. 또한 미생물 다양성을 평가하기 위해 Alpha diversity 및 OTU abundance 분석을 수행한 결과, 전반적으로 아델리펭귄의 장내 미생물 다양성이 황제펭귄보다 높은 것을 확인하였고, PCoA를 기반으로 한 Beta diversity 분석을 통해 두 개체군 간 장내 미생물 군집에 차이가 존재함을 확인하였다. PICRUSt를 활용한 기능적인 차원의 KEGG pathway 분석을 통해서는 아델리펭귄과 황제펭귄 시료에서 nucleoside and nucleotide biosynthesis pathway가 가장 많이 존재하는 것을 확인하였다. 본 연구를 통해 남극 아델리펭귄과 황제펭귄의 장내미생물 구성과 다양성을 비교분석 할 수 있었다. 본 연구 결과는 향후 펭귄의 먹이 섭식 관련 연구에 활용될 수 있으며, 더 나아가 다양한 남극 생물의 장내미생물 메타지놈 분석에 대한 기초가 될 수 있을 것이다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2002년도 총회 및 추계학술발표회
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• pp.99.2-99
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• 2002

• 환경위생공학
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• 제16권3호
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• pp.62-71
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• 2001

The present study was performed to examine the community structure of benthic macroinvertebrates in the provincial park of Mt. Daedun and its nearby region. Sampling was conducted two times in May.June and October.November, 2000. Main two areas are Mt. Anpyong (470.0m) and Mt. Daedun (877.0m) area. Total taxa of benthic macroinvertebrates were 111 species, 47 families, 15 orders, 6 classes in 4 phyla. Aquatic insects were composed of 29 species in ephemeroptera, 10 species in odonata, 7 species in plecoptera, 2 species in hemiptera, 2 species in megaloptera, 23 species trichuptera, 6 species in coleoptera and 17 species in diptera. Other non-insects were composed of 1 species in platyhelminthes, 8 species in gastropoda, 2 species in oligochaeta, 3 species in hirudinea and 1 species in crustacea. Ephemeroptera, trichoptera and plecoptera as indicators in clean water were very abundantly. Occurrence species at each surrey area was 77 species at Mt. Anpyong area and 89 species at Mt. Daedun area, respectively. Mean values of species diversity indices were 3.04 and 2.69, respectively. According to the saprobic system based on the species diversity indices of benthic macroinvertebrates, Mt. Anpyong region are determined as polysaprobic area or ${\beta}-mesosaprobic$ area and Mt. Daedun region are determined as polysaprobic area, $\beta-mesosaprobic$ area or ${\alpha}-mesosaprobic$ area.

• Fisheries and Aquatic Sciences
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• 제24권9호
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• pp.297-310
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• 2021

The rockworm gut flora was identified at each growth stage to elucidate the composition of the bacterial community. The source material was Marphysa sanguinea fed regular feed and fed biofloc at the adult stage in parallel. The systematic bacterial community composition was determined based on the next-generation sequencing method, and alpha diversity and beta diversity were conducted to access the species diversity within and between the bacterial communities, respectively. The composition of the gut flora changed considerably as the rockworms developed. The shift in the gut flora was confirmed at the phylum, family, and genera level of the bacterial communities. The Vibrio species associated with high rockworm mortality occupied 7.7% of the gut flora at the larval stage; however, they disappeared in the healthy adult gut. Moreover, different gut flora was observed between adults fed regular feed and those fed biofloc. Specifically in the biofloc-fed adult gut, several immune relevant and water-purifying bacteria were detected. The biofloc-fed adult gut flora could decompose and mineralize organic sediment, and thus be effectively utilized for integrated multitrophic aquaculture. The Venn diagram revealed that only two bacterial species were shared throughout all growth stages, and the biofloc-fed adults exhibited the highest diversity within the bacterial community.

• Mycobiology
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• 제50권5호
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• pp.302-316
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• 2022

Many Apiospora species have been isolated from bamboo plants - to date, 34 bambusicolous Apiospora species have been recorded. They are known as saprophytes, endophytes, and plant pathogens. In this study, 242 bambusicolous Apiospora were isolated from various bamboo materials (branches, culms, leaves, roots, and shoots) and examined using DNA sequence similarity based on the internal transcribed spacer, 28S large subunit ribosomal RNA gene, translation elongation factor 1-alpha, and beta-tubulin regions. Nine Apiospora species (Ap. arundinis, Ap. camelliae-sinensis, Ap. hysterina, Ap. lageniformis sp. nov., Ap. paraphaeosperma, Ap. pseudohyphopodii sp. nov., Ap. rasikravindrae, Ap. saccharicola, and Ap. sargassi) were identified via molecular analysis. Moreover, the highest diversity of Apiospora was found in culms, and the most abundant species was Ap. arundinis. Among the nine Apiospora species, two (Ap. hysterina and Ap. paraphaeosperma) were unrecorded in Korea, and the other two species (Ap. lageniformis sp. nov. and Ap. pseudohyphopodii sp. nov.) were potentially novel species. Here, we describe the diversity of bambusicolous Apiospora species in bamboo organs, construct a multi-locus phylogenetic tree, and delineate morphological features of new bambusicolous Apiospora in Korea.

• 생명과학회지
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• 제28권1호
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• pp.105-109
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• 2018

생물다양성은 생존하는 유기체들의 변이성으로 정의하며 지구상의 생물의 다양성과 생태계를 구성하는 복잡한 상호작용을 일컫는다. 본 연구는 합천군 덕진천에 서식하는 동물의 종조성과 다양성을 공간적 시간적 양상으로 실시하였다. 2016년 시즌에 동정된 포유류, 연골어류, 경골어류, 조류, 양서류, 파충류, 어류 종의 수는 55분류군이었다. 포유류의 Berger-Parker's index (BPI)는 0.233(지점 A)에서 0.333(지점 D)로 나타났다. 포유류와 조류에 대한 Shannon-Weaver index (H')와 두 다른 다양성 척도(N1과 N2)는 상류지역이 하류 지역보다 높았다. 동물 분류군에 대한 ${\beta}$-다양성은 어류 0.229에서 무척추동물 0.339까지 나타났다. 동물종에 대한 풍부도 지수는 지점과 시기에 따라 변화가 있었다. 지점 A는 포유류, 조류, 양서/파충류에서 높은 풍부도를 나타내었다. 비록 다섯 동물 강에 대한 풍부도 지수(R1, R2)가 시즌 별로 다르지만 유의성을 나타내지는 않았다. 균등도 지수(E1-E5) 역시 시즌 별로 다르지만 유의성을 나타내지는 않았다.