• Membrane and Water Treatment
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• 제10권6호
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• pp.395-404
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• 2019

The influence of chlorine on marine bacterial communities was examined in this study. A non-chlorine-adapted marine bacterial community (NCAM) and a chlorine-adapted bacterial community (CAM, bacterial community treated with $0.2mg-Cl_2/L$ chlorine) were cultivated for 1 month. A distinct difference was observed between the NCAM and CAM, which shared only eight operational taxonomic units (OTUs), corresponding to 13.1% of the total number of identified OTUs. This result suggested that chlorine was responsible for the changes in the marine bacterial communities. Kordiimonas aquimaris was found to be a chlorine-resistant marine bacterium. The effect of intermittent chlorination on the two marine biofilm communities formed on the reverse osmosis (RO) membrane surface was investigated using various chlorine concentrations (0, 0.2, 0.4, 0.6 and 0.8 mg $Cl_2/L$). Although the average number of adherent marine bacteria on the RO membrane over a period of 7 weeks decreased with increasing chlorine concentration, disinfection efficiencies showed substantial fluctuations throughout the experiment. This is due to chlorine depletion that occurs during intermittent chlorination. These results suggest that intermittent chlorination is not an effective disinfection strategy to control biofilm formation.

• Entomological Research
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• 제48권6호
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• pp.559-566
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• 2018

In Korea, the centipede called "Wang-ji-ne" or "O-gong" is used as an important medicinal resource. This centipede has been known as Scolopendra subspinipes mutilans Koch 1878. Recent studies have assessed its taxonomic treatment in several geographical populations from China, Japan and Taiwan, but not Korea. We therefore attempted to assess exact species status for the Korean population of this subspecies using both morphological and DNA barcode methods. The result inferred from DNA barcoding showed that the Korean population is S. mutilans explicitly separated from S. subspinipes. Within S. mutilans, the Korean population is morphologically identical and genetically closer to the Chinese population rather than island populations of Japan and Taiwan. Particularly, the mainland populations from Korea and China share six haplotypes from 17 despite being far apart geographically.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.21-21
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• 2019

백양꽃(Lycoris koreana)이 속해 있는 상사화속(Lycoris)은 종간 잡종이 쉽게 일어나 많은 자연교잡종을 가지고 있어 식물의 종분화와 진화를 연구하는데 흥미로운 분류군이다. 그러나 이런 사유로 명백한 분류학적 차이가 있음에도 불구하고 대상종의 분류학적 위치의 설정에 문제가 발생되어 계급의 설정에 혼란을 가져오기도 한다. 특히 한국산 상사화속의 종 분류는 그동안 많은 형태학적, 분계학적, 화분학적, 세포학적, 분자생물학적 연구가 이루어져 있음에도 아직도 도감과 많은 문헌에서 오류와 오동정의 문제점을 가지고 있다. 특히 백양꽃에 대하여서는 Nakai에 의해 신종으로 설정된 이래 일본에 분포하는 동 속 식물과의 관계 분석의 오류로 계급의 설정에 현재까지 다양한 문제가 발생되고 있다. 백양꽃은 전라남도 백양산에 분포하고, 포가 자주색이고, 꽃의 크기가 작으며, 화사와 화주가 적색 또는 암적색인 특징으로 Nakai에 의해 신종으로 설정되었다. 이후 Nakai와 Lee는 L. koreana 가 한국에만 분포하는 것으로 보고 한국 특산종으로 취급하였다. 그러나 백양꽃의 실체에 대하여 많은 논의가 있었으나 Lee and Oh는 L. radiata로 동정하였고, Yang은 L. koreana는 한국에 분포하지 않고 L. sanguinea만이 분포하는 것으로 보고하였다. Koyama는 L. sanginea에 대하여 L. sanguinea와 L. kuishiana를 비교하여 수술이 화관 밖으로 돌출되어 있는 점 외에는 L. koreana와 차이가 없음을 들어 각각 L. sanguinea var. sanguinea, L. sanguinea var. kuishiana 그리고 L. sanguinea var. koreana로 재설정 하였고 이는 한국과 일본학자들에 의해서도 거의 받아들여지고 있으나 본 연구를 통하여 L. koreana의 종(species)으로의 계급 부여와 한국특산식물 설정의 타당한 결과를 도출하였다.

• 한국환경과학회지
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• 제30권12호
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• pp.1015-1025
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• 2021

Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K⁺, and Mg²⁺ contents were observed in winter rye cultivation.

• ALGAE
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• 제37권3호
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• pp.205-211
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• 2022

The trend in naming genera based almost exclusively on molecular data, and not on morphological diagnostic characters, is increasing. In bifurcating phylogenetic trees generic cut-offs are arbitrary, but at the bare minimum nomenclatural changes should be supported by multiple phylogenetic methodologies using appropriate models for all the various gene partitions, strong support with all branch support methods, and should also result in adding to our knowledge of the interrelationships of taxa. We believe that a recent taxonomic treatment of the genus Pyropia (Yang et al. 2020) into several genera is unwarranted. We reanalysed the data presented in the recent article, using additional phylogenetic methods. Our results show that many of the newly established genera are not well supported by all methods, and the new circumscription of the genus Pyropia renders it unsupported. We also tested additional outgroups, which were previously suggested as sister to Pyropia, but this did not substantially change our conclusions. These generic nomenclatural changes of the previously strongly supported genus Pyropia, do not shed light on the evolution of this group and have serious consequences in these commercially important algae, that are also governed by a plethora of regulation and by-laws that now need to be amended. We suggest that the over-splitting of groups based only on poorly produced and modestly supported phylogenies should not be accepted and that the genus Pyropia sensu Sutherland et al. (2011) be restored.

• Journal of Periodontal and Implant Science
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• 제50권3호
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• pp.171-182
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• 2020

Purpose: The aims of this study were to examine the salivary microbiota in conditions of periodontal health and disease and to explore microbial changes following nonsurgical periodontal treatment. Methods: Non-stimulated saliva samples were collected from 4 periodontally healthy participants at baseline and from 8 patients with chronic periodontitis at baseline and 3 months following nonsurgical periodontal therapy. The V3 and V4 regions of the 16S rRNA gene from the DNA of saliva samples were amplified and sequenced. The salivary microbial compositions of the healthy participants and patients with periodontitis prior to and following nonsurgical treatment of periodontitis were compared based on the relative abundance of various taxa. Results: On average, 299 operational taxonomic units were identified in each sample. The phylogenetic diversity in patients with periodontitis was higher than that in healthy participants and decreased following treatment. The abundance of the phylum Spirochaetes and the genus Treponema in patients with periodontitis was 143- and 134-fold higher than in the healthy control group, respectively, but decreased significantly following treatment. The species that were overabundant in the saliva of patients with periodontitis included the Peptostreptococcus stomatis group, Porphyromonas gingivalis, the Fusobacterium nucleatum group, Parvimonas micra, Porphyromonas endodontalis, Filifactor alocis, and Tannerella forsythia. The phylum Actinobacteria, the genus Streptococcaceae_uc, and the species Streptococcus salivarius group were more abundant in healthy participants than in those with periodontitis. There was a trend toward a decrease in disease-associated taxa and an increase in health-associated taxa following treatment. Conclusions: Our results revealed differences in the taxa of salivary microbiota between conditions of periodontal health and disease. The taxa found to be associated with health or disease have potential for use as salivary biomarkers for periodontal health or disease.

• Asian-Australasian Journal of Animal Sciences
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• 제30권9호
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• pp.1261-1269
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• 2017

Objective: The effect of flavonoids from alfalfa on the microbial flora was determined using molecular techniques of 16S ribosome deoxyribonucleic acid (rDNA) analysis. Methods: Four primiparous Holstein heifers fitted with ruminal cannulas were used in a $4{\times}4$ Latin square design and fed a total mixed ration to which alfalfa flavonoids extract (AFE) was added at the rates of 0 (A, control), 20 (B), 60 (C), or 100 (D) mg per kg of heifer BW. Results: The number of operational taxonomic units in heifers given higher levels of flavonoid extract (C and D) was higher than for the two other treatments. The Shannon, Ace, and Chao indices for treatment C were significantly higher than for the other treatments (p<0.05). The number of phyla and genera increased linearly with increasing dietary supplementation of AFE (p<0.05). The principal co-ordinates analysis plot showed substantial differences in the microbial flora for the four treatments. The microbial flora in treatment A was similar to that in B, C, and D were similar by the weighted analysis. The richness of Tenericutes at the phylum level tended to increase with increasing AFE (p = 0.10). The proportion of Euryarchaeota at the phylum level increased linearly, whereas the proportion of Fusobacteria decreased linearly with increasing AFE supplementation (p = 0.04). The percentage of Mogibacterium, Pyramidobacter, and Asteroleplasma at the genus level decreased linearly with increasing AFE (p<0.05). The abundance of Spirochaeta, Succinivibrio, and Suttonella at the genus level tended to decrease linearly with increasing AFE (0.05

• 식물분류학회지
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• 제37권4호
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• pp.477-502
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• 2007

본 연구에서는 Aconitum alboviolaceum Kom. complex에 속하는 6종 중 한국산 4종(A. alboviolaceum, A. longecassidatum, A. pseudolaeve, A. quelpaertense)을 대상으로 형 태 및 주성분분석(Principal Components Analysis)과 엽록체 DNA psbA-trnH IGS, trnL intron 및 tmL-trnF IGS 구간의 분석을 통해 각 분류군의 타당성을 검토하고 그 한계 및 분류학적 위치를 명확히 설정하고자 하였다. 형태분석 결과, 기존에 보고되었던 주요 식별형질에서 형태변이가 종 및 개체군 수준에서 복잡한 형태로 나타났으며 주성분분석 결과 각 분류군들은 종 및 개체군 수준에서 유집 되지 않고 연속적으로 혼합된 양상을 보였다. 염기서열 분석 결과, l0개의 염기치환과 3개의 indel이 관찰되었고, 이를 통해 얻어진 neighbor-joining tree에서 나타난 4개의 그룹은 종 및 개체군을 반영하지 않았다. 따라서, 본 연구에서는 complex 내 분류군들에 관한 기존의 형태형질에 근거한 분류체계를 지지하지 않으며, 이들 분류군 간의 분류체계에 대한 재고가 필요하다고 본다.

• 식물분류학회지
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• 제38권2호
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• pp.121-149
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• 2008

한국산 족도리풀속(Asarum L.) 6종 4변종에 대한 외부 형태학적 연구를 수행하여 새로운 종 검색표를 작성하고, 분류학적 처리를 하였다. 금오족도리풀(A. patens), 각시족도리풀(A. misandrum), 무늬족도리풀(A. versicolor)은 꽃받침 열편의 형태, 화주돌기의 형태와 색, 잎의 모용과 무늬 등에서 다른 종들과 뚜렷이 구분되어 독립된 종임을 지지해 주었다. 여러 학자에 의해 종 또는 변종으로 기재되었던 뿔족도리풀(A. sieboldii var. cornutum), 자주족도리풀(A. koreanum), 개족도리풀(A. maculatum), 선운족도리풀(A. sonunsanense)은 꽃받침 열편이 자색이고 굴곡되는 등 족도리풀(A. sieboldii)과 매우 유사하여 A. sieboldii for. cornutum, A. sieboldii for. koreanum, A. sieboldii for. maculatum, A. sieboldii for. sonunsanense로 처리하였다. 또한 꽃받침 열편이 뒤로 젖혀지고 잎 이면에 털이 있어 형태적으로 매우 유사한 서울족도리풀(A. heterotropoides var. seoulense)과 만주족도리풀(A. heterotropoides var. mandshuricum)은 A. mandshuricum for. seoulense와 A. mandshuricum for. mandshuricum으로 학명을 정리하였으며, 일본에만 분포하는 A. heterotropoides var. heterotropoides는 독특한 꽃받침 열편의 형태 등을 가져 독립된 종인 A. heterotropoides로 취급하였다. 따라서 한국산 족도리풀속은 3종 7품종으로 재정리하였다.

• 한국환경기술학회지
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• 제19권6호
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• pp.550-555
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• 2018

국제 해사기구 (IMO)에서 MARPOL 73/78은 조문과 여섯 개의 부속서로 구성되어 있다. Annex IV는 선박의 하수를 규제한다. 2012년 제 64회 결의안에서 선박에서 배출되는 하수 중 영양염류를 제거하도록 규제하였다. 2014년 해양수산부의 지원으로 영양염류를 제거 할 수 있는 대용량 폐수처리 장치를 개발하였다. Sequence Batch Reactor (SBR)와 Membrane Bio Reactor (MBR)를 결합한 새로운 공정이 개발되었다. 현존하는 SBR 공정의 사이클에서는 침전을 제외하고 통기 및 교반만을 사용하였고, 상기 막은 처리 된 물을 배출 시키는데 사용하였다. 본 연구에서는 MACROGEN 사의 NGS 분석 기술을 이용하여 Bench 규모 폐수처리 설비를 이용한 하수처리장 원수를 처리하기 위한 최적 운전조건에서 폭기조 내 미생물의 우점종을 분석하였다. 그 결과 Bacteroidetes는 호기성 박테리아의 27.1 %를 차지했으며 Gammaproteobacteria는 혐기성 박테리아의 16.8 %를 차지하였다. Operational taxonomic unit ratio에 Others 항목이 차지하는 비율도 상당하다고 볼 수 있는데 기존의 오수처리를 위해 필요했던 미생물 외에 아직 NCBI (National center for Biotechnology Information)에 등록되지 않은 미생물일 가능성이 있어 추후 연구가 필요하다고 판단된다.