• ALGAE
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• v.36 no.2
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• pp.123-135
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• 2021

The taxonomy of green microalgae relies traditionally on morphological traits but has been rapidly changing since the advent of molecular methods. Stichococcus Nägeli is a cosmopolitan terrestrial algal genus of the class Trebouxiophyceae that has recently been split into seven lineages, which, along with Pseudostichococcus, comprise the Stichococcuslike group; there is a need to further characterize these genera, since they are morphologically enigmatic. Here we used organic osmolytes as chemotaxonomic marker to verify the phylogenetic position of Stichococcus-like strains and were also able to exclude a strain hitherto identified as Gloeotila contorta from this group. Stichococcus-like organisms, including those recently revised, were characterized by the production of the polyol sorbitol and the disaccharide sucrose in high amounts, as is typical of Prasiola-clade algae. The results demonstrate that organic osmolyte chemotaxonomy can support green algal taxonomic designations as fundamental research.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.393-397
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• 2021

The unrecorded fungus Galactomyces pseudocandidus de Hoog & M.T. Sm. was isolated and cultured from an introduced species, Procambarus clarkii, in Korea. Two related species, Galactomyces citri-aurantii and Geotrichum candidum, have been reported, but no other Galactomyces spp. have been found in Korea. In this study, we isolated G. pseudocandidus from the digestive tract of American crayfish using RGY (river water-glucose-yeast) medium and then compared the morphological and molecular characteristics of this species with those of related species. As a result, we confirmed that G. pseudocandidus is an unrecorded fungus in Korea, so we described and reported the cultural characteristics and microstructures, such as conidia.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.66.2-67
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• 2000

No Abstract, See Full Text

• The Plant Pathology Journal
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• v.25 no.1
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• pp.86-90
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• 2009

In November 2008, typical powdery mildew symptoms were observed on leaves of Arabidopsis thaliana ecotype Col-0 plants in a growth room under controlled laboratory conditions at Korea University, Seoul. The disease was characterized by the appearance of white powder-like fungal growth on the surface of infected leaves. As the disease progressed, infected leaves exhibited chlorotic or necrotic brown lesions, and leaf distortion and senescence. Conidiophores of the causal fungus were hyaline, unbranched, 3-4 celled, cylindrical, and $80-115{\times}6-9{\mu}m$ in size. Singly produced conidia (pseudoidium type) were hyaline, oblong to cylindrical or oval in shape, and $26-55{\times}15-20{\mu}m$ in size with a length/width ratio of average 3, angular/rectangular wrinkling of outer wall and no distinct fibrosin bodies. Appressoria on the hyphae were multi-lobed. These structures are typical of the powdery mildew Oidium subgenus Pseudoidium, anamorph of the genus Erysiphe. The measurements of the fungal structures coincided with those of Erysiphe cruciferarum. The phylogenetic analysis using ITS rDNA sequences revealed that the causal fungus Erysiphe sp. KUS-F23994 is identical to E. cruciferarum. The isolated fungus incited powdery mildew symptoms on the inoculated Arabidopsis leaves, which proved Koch's postulates. Taken all data together, we first report the occurrence of powdery mildew disease of A. thaliana caused by Erysiphe cruciferarum in Korea.

• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.9-15
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• 2019

Artiodactyla, which is an even-toed mammal, widely inhabits worldwide. In recent years, wild Artiodactyla species have attracted public attention due to the rapid increase of crop damage and road-kill caused by wild Artiodactyla such as water deer and wild boar and the decrease of some species such as long-tailed goral and musk deer. In spite of such public attention, however, there have been few studies on Artiodactyla in Korea, and no studies have focused on the trend analysis of Artiodactyla, making it difficult to understand actual problems. Many recent studies on trend used text-mining and co-occurrence analysis to increase objectivity in the classification of research subjects by extracting keywords appearing in literature and quantifying relevance between words. In this study, we analyzed texts from research articles of three countries (Korea, China, and Japan) through text-mining and co-occurrence analysis and compared the research subjects in each country. We extracted 199 words from 665 articles related to Artiodactyla of three countries through text-mining. Three word-clusters were formed as a result of co-occurrence analysis on extracted words. We determined that cluster1 was related to "habitat condition and ecology", cluster2 was related to "disease" and cluster3 was related to "conservation genetics and molecular ecology". The results of comparing the rates of occurrence of each word clusters in each country showed that they were relatively even in China and Japan whereas Korea had a prevailing rate (69%) of cluster2 related to "disease". In the regression analysis on the number of words per year in each cluster, the number of words in both China and Japan increased evenly by year in each cluster while the rate of increase of cluster2 was five times more than the other clusters in Korea. The results indicate that Korean researches on Artiodactyla tended to focus on diseases more than those in China and Japan, and few researchers considered other subjects including habitat characteristics, behavior and molecular ecology. In order to control the damage caused by Artiodactyla and to establish a reasonable policy for the protection of endangered species, it is necessary to accumulate basic ecological data by conducting researches on wild Artiodactyla more.

• Journal of Ecology and Environment
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• v.43 no.4
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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.

• Journal of Life Science
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• v.27 no.4
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• pp.408-416
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• 2017

This research aimed to identify the diversity and the distribution of invasive alien plant species in the metropolitan city of Busan, South Korea. According to our results, we discovered 10 species of invasive alien plants distributed in Busan, demonstrating that this urban area has a high domestic plant diversity. A cluster analysis identified that the dominant communities of Aster pilosus, Lactuca serriola, Ambrosia artemisiifolia, Rumex acetosella and Solanum carolinense were highly similar in species composition. Different species of invasive alien plants tended to occur together in dominant communities, indicating their preference for shared habitats. The most extensively distributed species in Busan were Lactuca serriola (16 districts), followed by Ambrosia artemisiifolia (11 districts), Aster pilosus (11 districts) and Rumex acetosella (10 districts). The administrative districts with the most diverse invasive alien plants were Gangseo-gu (8 species) and Buk-gu (8 species), which are both areas with high human interference and diverse habitats. Additional environmental information was collected for these species' habitats in Busan. The results of this research can be used to assess the current status of invasive alien plants in Busan and can provide basic data useful for effectively controlling and preventing the spread of invasive plants.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.379-385
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• 2014

Two marine ulvalean species (Chlorophyta) were collected from the southern and eastern coasts of Korea. One is morphologically characterized by usually unbranched or little branched ribbon-shaped thalli, fronds with spirally twisted basal portions and usually undulate margins and 1 (-2) pyrenoids per cell. The other has irregularly shaped thalli, undulate and dentate margins in the fronds, small macroscopic denticulations along the margin and (1-) 2-3 pyrenoids per cell. In phylogenetic tree based on molecular data, the two species nest in the same clade with Ulva flexuosa and U. rigida, respectively. These two Korean entities are identified as U. flexuosa and U. rigida, respectively, based on morphological and molecular analyses. This is the first record of Ulva flexuosa and U. rigida in Korea.

• Ocean and Polar Research
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• v.38 no.4
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• pp.295-301
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• 2016

The nomenclature of the sea nettle jellyfish from Korea was initially described as Dactylometra quinquecirrha Agassiz, 1862. However its identity has been questioned on the basis of its local distribution and molecular data. Here, we examined morphology and DNA sequences of nuclear rDNA using specimens collected from southern Korean waters in August 2014. Based on morphological characteristics (bell size, umbrella pattern, number of tentacles and lappets) and distribution locality, we reassign the Korean D. quinquecirrha to Chrysaora pacifica (Goette, 1886), and provide a re-description accordingly. The molecular identity of C. pacifica was further confirmed by comparison of nuclear ribosomal DNA sequences.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.304-313
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• 1992

The agricultural industry is beset by continuing demands to decrease the use of pest control agents which employ toxic modes of action. Although there are real problems of pesticide resistance, and sometimes overuse or redistribution in the environment, much criticism results from a lack of appreciation of how small is the risk involved. Whatever the background reasons, research and development for pesticide alternatives, particularly within Integrated Pest Management systems, is clearly of high priority. Currently available approaches, including use of natural products and molecular biology, are often regarded with naive optimism and require critical appraisal. For the future, methods of pest control based on chemicals with non-toxic modes of action (e.g. pheromones) continue to offer promise but, for widespread use, will require their integration with biological agents and development by means of plant molecular biology.