• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.593-598
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• 2004

The arsenical resistance (ars) operon was cloned from a 67-kilobase pair (kb) plasmid, which was previously shown to be responsible for arsenic salts resistance in K. oxytoca D12. When plasmid pAE48, carrying the ars operon, was transformed into E. coli, transformed cells displayed enhanced survival in the presence of 4 mM arsenite, 50 mM arsenate, or 0.4 mM antimonite. The nucleotide sequence of the 5.6-kb fragment encoding arsenical resistance revealed five open reading frames (ORFs), which were predicted to encode polypeptides of 12.8 (arsR), 13.4 (arsD), 62.6 (arsA), 45 (arsB), and 16.7 (arse) kilodaltons (kDa). Each ORF was preceded by a ribosome binding site. A putative promoter-like sequence was identified upstream of arsR, and a possible termination site was found downstream of arsC. When the deduced amino acid sequences of the K. oxytoca Dl2 Ars proteins were compared with the amino acid sequences of the E. coli R773 Ars proteins, a significant amino acid similarity was observed (87.9％ for ArsR, 89.2％ for ArsD, 83.2％ for ArsA, 92.6％ for ArsB, and 91.3％ for ArsC), suggesting an evolutionary relationship of the ars genes of E. coli plasmid R773 and K. oxytoca Dl2.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.421-426
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• 2019

Background: Wolbachia are among the most prevalent endosymbiotic bacteria and induce reproductive anomalies in various invertebrate taxa. The bacterium has huge impacts on host reproductive biology, immunity, evolution, and molecular machinery. However, broad-scale surveys of Wolbachia infections at the order scale, including the order Coleoptera, are limited. In this study, we investigated the Wolbachia infection frequency in 201 Coleopteran insects collected in Korea. Results: A total of 26 species (12.8%) belonging to 11 families harbored Wolbachia. The phylogenetic trees of based on partial 16S rRNA gene sequences and partial Wolbachia surface protein (wsp) gene sequences were largely incongruent to that of their hosts. This result confirms that Wolbachia evolved independently from their hosts, Conclusion: Phylogenetic trees suggest that complex horizontal gene transfer and recombination events occurred within and between divergent Wolbachia subgroups.

• 한국과학교육학회지
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• 제36권3호
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• pp.509-517
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• 2016

학생들의 진화에 대한 대안개념(목적론, 용불용설 등)이 과학사에서 나타나는 설명의 발전 형태와 유사하다는 연구는 있었다. 하지만 과학사적으로 설명의 발달과정을 반영하여 부분점수를 주는 평가방식은 활용되지 않았다. 이 연구의 목적은 창조론에서 자연선택까지 과학사적 발달과정을 반영하여 부분점수를 주는 방법을 제안하고 이 방법이 타당한지에 대한 양적인 증거를 수집하는 것이다. 이 연구는 과학사에 근거하여 진화개념검사도구의 학생응답을 순위선다형점수로 변환하고 부분채점모형의 라쉬모델분석을 포함한 통계적 방법으로 새로운 평가방식이 타당한지 확인하였다. 또한 개념발달이 인간, 동물, 문항의 상황에 따라 다른지 확인하였다. Ha(2007)가 개발한 검사도구를 활용하여 1711명의 초, 중, 고등학생과 비전공, 전공생물 교사를 대상으로 생성한 자료를 통하여 분석하였다. 창조론, 목적, 의도, 용불용설, 자연선택에 0점에서 4점씩 부분점수로 제시한 평가방법은 Cronbach alpha를 통한 내적일관성 신뢰도, 라쉬분석의 MNSQ값 등 통한 문항적합도를 확인한 결과 타당한 것으로 확인되었다. 초등학생과 중학생들의 개념수준은 의도에서 용불용설 단계에, 고등학생부터 용불용설 이후의 단계로 개념발달이 이루어지고 있었다. 진화설명의 발달 과정은 인간, 동물, 식물에 따라 차이가 나타남을 확인할 수 있었다. 이 연구는 과학사와 학생들의 개념발달이 유사하다는 기존의 주장에 새로운 양적증거를 추가하고, 진화개념 평가를 위한 새로운 분석방법을 제안한다.

• 한국균학회지
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• 제51권3호
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• pp.179-190
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• 2023

Grapevine downy mildew, caused by Plasmopara viticola, significantly damages vineyards and is one of the most devastating diseases affecting cultivated grapes worldwide. In this study, we characterized the phenotypic and molecular traits of 11 P. viticola isolates from four grape-growing regions in South Korea. Additionally, we investigated the diversity of pathogenicity among these isolates and conducted an assay to evaluate the response of grape cultivars to P. viticola infection. Lemon-shaped sporangia were identified in the collected isolates, which released zoospores into the suspension at room temperature. Within a few hours of inoculation, the zoospores developed germ tubes. We tested 11 P. viticola isolates for pathogenicity in 845 grape cultivars to screen for grape host resistance to downy mildew infection. Among the tested isolates, JN-9 showed the highest virulence. Grape cultivars displayed varying phenotypic reactions to P. viticola infection: approximately 7% were highly susceptible, 41% were susceptible, 20% were moderately susceptible, 8% were resistant, and 24% exhibited extreme resistance. Phylogenetic analysis based on four genomic regions (internal transcribed spacer 1 [ITS1], actin, beta-tubulin, and cytochrome c oxidase II) revealed a close evolutionary relationship among all the Korean isolates, forming a single monophyletic lineage. Notably, these isolates showed greater similarity to European isolates than to American isolates. This comprehensive study contributes to a deeper understanding of the identity and behavior of P. viticola, which is crucial for developing effective resistance strategies against this pathogen in grape cultivars cultivated in South Korea.

• 식물분류학회지
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• 제46권2호
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• pp.129-148
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• 2016

Plant species on oceanic islands comprise nearly 25% of described vascular plants on only 5% of the Earth's land surface yet are among the most rare and endangered plants. Conservation of plant biodiversity on islands poses particular challenges because many species occur in a few and/or small populations, and their habitats on islands are often disturbed by the activity of humans or by natural processes such as landslides and volcanoes. In addition to described species, evidence is accumulating that there are likely significant numbers of "cryptic" species in oceanic archipelagos. Plant systematists, in collaboration with others in the botanical disciplines, are critical to the discovery of the subtle diversity in oceanic island floras. Molecular data will play an ever increasing role in revealing variation in island lineages. However, the input from plant systematists and other organismal biologists will continue to be important in calling attention to morphological and ecological variation in natural populations and in the discovery of "new" populations that can inform sampling for molecular analyses. Conversely, organismal biologists can provide basic information necessary for understanding the biology of the molecular variants, including diagnostic morphological characters, reproductive biology, habitat, etc. Such basic information is important when describing new species and arguing for their protection. Hybridization presents one of the most challenging problems in the conservation of insular plant diversity, with the process having the potential to decrease diversity in several ways including the merging of species into hybrid swarms or conversely hybridization may generate stable novel recombinants that merit recognition as new species. These processes are often operative in recent radiations in which intrinsic barriers to gene flow have not evolved. The knowledge and continued monitoring of plant populations in the dynamic landscapes on oceanic islands are critical to the preservation of their plant diversity.

• Animal cells and systems
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• 제8권4호
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• pp.295-300
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• 2004

In the breeding colony of black-tailed gull, as nests of conspecific neighbors are very closely located, chicks are permanently exposed by sound and visual stimuli produced by adult conspecifics approaching their nests. The chicks, therefore, may need to learn ways to appropriately respond to their parents approach. In this study we experimentally manipulated sensory stimulation that is potentially provided by the parents to the offspring. Chicks incubated in the laboratory were exposed to a mew call of the conspecific adult. Then they were tested in three situations differing in sensory stimulation: 1) visual stimulation only, 2) auditory stimulation only, and 3) Simultaneous visual and auditory stimulations. We observed occurrence of different response of the chicks, which were categorized into three behaviors (begging call response, chirirah call and pecking behavior). We also investigated intensity of the chicks call in response to the different stimulations and the degree of response with age. The chicks exposed to only auditory stimulation made significantly more chirirah calls. The intensities (dB) of the mew call and chicks chirirah call were directly correlated. On the other hand, when chicks just saw the stuffed adult gull, they responded significantly more with a begging call and pecking behavior. In the situation of costimulation, the chicks responded with a begging call and pecking, but less frequently than visual stimulation only. The results suggest that young black-tailed gulls use call repertories to properly respond to parents behavior. Such results suggest an evolutionary process for uncreasing their survival rate in a group breeding site.

• ALGAE
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• 제33권3호
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• pp.269-278
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• 2018

Ocean warming can have significant negative impacts on population genetic diversity, local endemism and geographical distribution of a wide range of marine organisms. Thus, the identification of conservation units with high risk of extinction becomes an imperative task to assess, monitor, and manage marine biodiversity for policy-makers. Here, we surveyed population structure and genetic variation of the red seaweed Gracilaria vermiculophylla along the coast of China using genome-based amplified fragment length polymorphism (AFLP) scanning. Regardless of analysis methods used, AFLP consistently revealed a south to north genetic isolation. Populations at the southern coast of China showed unique genetic variation and much greater allelic richness, heterozygosity, and average genetic diversity than the northern. In particular, we identified a geographical barrier that may hinder genetic exchange between the two lineages. Consequently, the characterized genetic lineage at the southern coast of China likely resulted from the interplay of post-glacial persistence of ancestral diversity, geographical isolation and local adaptation. In particular, the southern populations are indispensable components to explore evolutionary genetics and historical biogeography of G. vermiculophylla in the northwestern Pacific, and the unique diversity also has important conservation value in terms of projected climate warming.

• 환경생물
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• 제23권4호
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• pp.335-342
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• 2005

We cloned seven genes encoding chitin synthases (CHSs) by PCR amplification from genomic DNAs of four strains of the genus Sporobolomyces and of Bensingtonia subrosea using degenerated primers based on conserved regions of the CHS genes. Though amino acid sequences of these genes were shown similar as 176 to 189 amino acids except SgCHS2, DNA sequences were different in size, which was due to various introns present in seven fragments. Alignment and phylogenetic analysis of their deduced amino acid sequences together with the reported CHS genes of basidiomycetes separated the sequences into classes I, II and III. This analysis also permitted the classification of isolated CHSs; SgCHS1 belongs to class I, BsCHS1, SaCHS1, SgCHS2, SpgCHS1, and SsCHS1 belong to class II, and BsCHS2 belongs to class III. The deduced amino acid sequences involving in class II that were discovered from five strains were also compared with those of other basidiomycetes by CLUSTAL X program. The bootstrap analysis and phylogenetic tree by neighbor-joining method revealed the taxonomic and evolutionary position for four strains of the genus Sporobolomyces and for Bensingtonia subrosea which agreed with the previous classification. The results clearly showed that CHS fragments could be used as a valuable key for the molecular taxonomic and phylogenetic studies of basidiomycetes.

• 환경생물
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• 제31권2호
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• pp.165-171
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• 2013

The distribution patterns of estuarine copepods were investigated in the Seomjin River estuary of southern Korea after heavy rains in August 2006. Tidal influence extended 16 km from the estuary mouth. Each estuary zone (Oligohaline salinity <5, mesohaline salinity 5~18, polyhaline salinity >18) changed within a range of about 5~6 km between low and high tides. A total of ten species were recorded, of which Pseudodiaptomus koreanus, Sinocalanus tenellus, and Tortanus dextrilobatus were predominant in the oligohaline zone; Acartia ohtsukai and Acartia forticrusa in the mesohaline zone; and A. erythraea, Calanus sinicus, Centropages dorsispinatus, Labidocera rotunda and Paracalanus parvus s. l. in the polyhaline zone. Their density was fastly reduced in the other zones. In particular, the oligohaline species migrated and aggregated into deeper water during ebb tides in order to retain their populations, while the same tendency was weaker for polyhaline species, suggesting that evolutionary traits primarily control population retention behaviors in estuarine environments.

• Journal of Species Research
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• 제9권4호
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• pp.339-345
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• 2020

The Earth contains billions of microbial species, although the vast majority cannot be cultured in laboratories and are thus considered unidentified and uncharacterized. Extremophiles are microorganisms that thrive in extreme conditions, including temperature, salinity, and pH. Extremophilic microorganisms have provided important insights for biological, metabolic, and evolutionary studies. Between 2017 and 2019, as part of a comprehensive investigation to identify bacterial species in Korea, eight bacterial strains were isolated from marine and non-marine environments in Jeju Island. These strains were cultured under extreme salinity or pH conditions. Phylogenetic analysis using 16S ribosomal RNA(rRNA) gene sequencing indicated that all eight strains belonged to the phyla Gammaproteobacteria, Bacilli, and Alphaproteobacteria. Based on their high 16S rRNA gene sequence similarities(>98.7%) and the formation of strong monophyletic clades with their closest related species, all isolated strains were considered as an unrecorded strain, previously unidentified species. Gram stain reaction, culture conditions, colony and cell morphology, biochemical characteristics, isolation source, and National Institute of Biological Resources(NIBR) IDs are described in this article. The characterization of these unrecorded strains provides information on microorganisms living in Korea.