• Microbiology and Biotechnology Letters
• /
• v.47 no.3
• /
• pp.423-433
• /
• 2019

Midgut microbiota is known to play a fundamental role in the biology and physiology of the agricultural pest, Spodoptera litura. This study reports the difference in the larval midgut microbiota of field-caught and laboratory-reared populations of S. litura by performing 16S rDNA amplicon pyrosequencing. Field populations for the study were collected from castor crops, whereas laboratory-reared larvae were fed on a regular chickpea based diet. In total, 23 bacterial phylotypes were observed from both laboratory-reared and field-caught caterpillars. Fisher's exact test with Storey's FDR multiple test correction demonstrated that bacterial genus, Clostridium was significantly abundant (p < 0.05) in field-caught larvae of S. litura as compared to that in the laboratory-reared larvae. Similarly, bacterial genera, such as Bradyrhizobium, Burkholderia, and Fibrisoma were identified (p < 0.05) predominantly in the laboratory-reared population. The Bray-Curtis dissimilarity matrix depicted a value of 0.986, which exhibited the maximum deviation between the midgut microbiota of the laboratory-reared and field-caught populations. No significant yeast diversity was seen in the laboratory-reared caterpillars. However, two yeast strains, namely Candida rugosa and Cyberlindnera fabianii were identified by PCR amplification and molecular cloning of the internal transcribed space region in the field-caught caterpillars. These results emphasize the differential colonization of gut residents based on environmental factors and diet.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.10
• /
• pp.1275-1283
• /
• 2022

Understanding soil microbial community structure in the Arctic is essential for predicting the impact of climate change on interactions between organisms living in polar environments. The hypothesis of the present study was that soil microbial communities and soil chemical characteristics would vary depending on their associated plant species and local environments in Arctic mature soils. We analyzed soil bacterial communities and soil chemical characteristics from soil without vegetation (bare soil) and rhizosphere soil of three Arctic plants (Cassiope tetragona [L.] D. Don, Dryas octopetala L. and Silene acaulis [L.] Jacq.) in different local environments (coal-mined site and seashore-adjacent site). We did not observe any clear differences in microbial community structure in samples belonging to different plant rhizospheres; however, samples from different environmental sites had distinct microbial community structure. The samples from coal-mined site had a relatively higher abundance of Bacteroidetes and Firmicutes. On the other hand, Acidobacteria was more prevalent in seashore-adjacent samples. The relative abundance of Proteobacteria and Acidobacteria decreased toward higher soil pH, whereas that of Bacteroidetes and Firmicutes was positively correlated with soil pH. Our results suggest that soil bacterial community dissimilarity can be driven by spatial heterogeneity in deglaciated mature soil. Furthermore, these results indicate that soil microbial composition and relative abundance are more affected by soil pH, an abiotic factor, than plant species, a biotic factor.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.1
• /
• pp.9-18
• /
• 2023

Fish samples were collected by a set net from April to December 2020 at the coastal waters off Tongyeong, Korea to determine fish species composition and seasonal variation. A total of 330,675 fish (1,032,578 g) representing 56 species belonging to 39 families were collected during the sampling period. The dominant species were Engraulis japonicus, Trachurus japonicus and Trichiurus japonicus, which accounted for 98.1% of the total number of individuals and 87.5% of the total biomass collected. E. japonicus and Chelidonichthys spinosus appeared every month off the coast of the Tongyeong. Cluster analysis based on the number of individuals of fish were classified into two groups at the dissimilarity level of 57%, and the results of ANOSIM analysis revealed significant differences in community structure among the two groups.

• The Korean Journal of Ecology
• /
• v.19 no.1
• /
• pp.93-104
• /
• 1996

Ecological approach to conservation of Korea's National Parks (KNP) was reviewed. Four hundred twenty five reports on 15 national parks for 80 years (1915~1994) were analyzed in consideration of phytocoenotic information such as flora, plant community and landscape. Total species was recorded as 157 familles, 752 genera, and 2,369 species (64.3% of Korean flora), in which is included only 75 species of the protected plant species designated by the Ministry of EnvironMent. Occurrence patterns of plant species in national parks were quite similar to one another, but those of plant community were rather unique. Seventy-four of 97 plant communities were reported in only one of 15 national parks, which might be regarded as an endemic or local vegetetation type. These facts are far different from actual status of the KNP＇s ecosystem, which indicate that not only original data in previous reports are less informative, but also tools of investigation and description are too subjective, and thus these can never afford to monitor the ecosystem. From the correlation analysis between 10 ecological characteristics, the following results were obtained: (1) the species richness was positively associated with the area of national park, (2) the number of visitors was related to landscape diversity, (3) occurrence of the designated species was closely related to the vegetation diversity. Numerical analysis (cluster analysis and ordination) using dissimilarity ratio by ecological characteristics divided 15 national parks into 4 groups. The first group, composed of national parks of Chirisan, $S\v{o}laksan$, Sokrisan, Hallasan, $T\v{o}kyusan$, Odaesan, and Sobaeksan, is recognized as the best national parks in terms of ecological conservation values. Nevertheless, they have been faced with the threat of visitor stress. This study will contribute to the establishment of strategy for appropriate conservation and sustainable use of KNP.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.42 no.5 s.305
• /
• pp.51-58
• /
• 2005

This paper proposes an efficient algorithm for extracting a tumor region from an breast ultrasound volume image by using rate-distortion (R-D) based seeded region growing. In the proposed algorithm the rate and the distortion represent the roughness of the contour and the dissimilarity of pixels in a region, respectively. Staring from an initial seed region set in each cutting plane of a volume, a pair of the seed region and one of adjacent regions whose R-D cost is minimal is searched and then they are merged into a new updated seed region. This procedure is recursively performed until the averaged R-D cost values per the number of contour pixels in the seed region becomes maxim. As a result, the final seed region has good pixel homogeneity and a much smooth contour. Finally, the tumor volume is extracted using the contours of the final seed regions in all the cutting planes. Experimental results show that the averaged error rate of the proposed method is shown to be below 4%.

• Korean Journal of Medicinal Crop Science
• /
• v.13 no.5
• /
• pp.249-253
• /
• 2005

This study was carried out to develop convenient and reproducible methods for identifying the genetic relationship among germplasms of Panax species based on molecular genetics. Using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analyses, genetic polymorphism of the Panax species was investigated with following cultivars and accessions, such as Chunpoong, Yunpoong, Kopoong, Sunpoong, and Kumpoong in domestic cultivars, Hwangsuk, Jakyung and Suckju in domestic accessions, and Panax quinquefolius L. and Panax japonicus C.A. Meyer in foreign introduced accessions, respectively. Specific DNA fragments ranging from 200 to 3,000 base pairs in size could be obtained with various ISSR and RAPD primers under the optimized PCR conditions. The dissimilarity coefficients among the genetic polymorphisms of ginseng cultivars and accessions were calculated from 0.26 to 0.90 in RAPD and from 0.12 to 0.89 in ISSR analysis, respectively. Eleven plant samples were grouped siblings together with cultivars and parents based on cluster analysis of genetic distance depending on genetic property such as origin of the species. In results, both RAPD and ISSR analyses were useful for identifying the genetic relationship among cultivars and accessions of Panax species at DNA level.

• Korean Journal of Environmental Biology
• /
• v.29 no.4
• /
• pp.379-387
• /
• 2011

Copepod nauplii plays an important role as a linker between the microbial food web and classical food chain in marine ecosystem and is an essential food source for early stage of many larval fishes. Study on the influencing factors on the growth of copepod naupliar stages has been rarely carried out in despite of these ecological significances. Many studies have shown that food availability and temperature are major factors to influence copepod growth. However, due to the complicated environment parameters in coastal ecosystem, the relationships between growth of copepods and influencing factors are still unclear under the natural condition. Growth rates of the copepod $Acartia$ $hongi$ nauplii were measured in Kyeonggi Bay from February to December 2001. $Acartia$ $hongi$ is numerically abundant and widespread predominant species in the coastal regions of the Yellow Sea and occurs continuously throughout the year, with a maximum peak in late spring. The naupliar growth rates of $Acartia$ $hongi$ by the artificial cohort method varied from 0.03 to 0.18 $day^{-1}$, with a mean of 0.09 $day^{-1}$. The overall naupliar growth rates showed a significantly positive relationship with the variation in water temperature. However, Previous study reported that the growth rates of adult $Acartia$ $hongi$ were primarily influenced by the variation in chlorophyll-$a$. Therefore, these differences demonstrated that the influencing factors of growth did not correspond with the developmental stages. The results of this study suggest that the dissimilarity of growth between nauplius and adult female resulted from the size-dependant difference in food availability and the growth of older developmental stages containing adults are more food-dependent than juveniles.

• Archives of design research
• /
• v.13 no.4
• /
• pp.195-201
• /
• 2000

To find out media's function on the various effects in communication, this paper reviews studies that utilize multimedia as a device for conveying information. We discuss multimedia as an integrated symbol system with advantages and also problems in representing information. The cognitive dissimilarity of media could be explained by various attributes of medium that are about physical characteristics and even cognitive actions. With advantages from integrated media and interactivity, multimedia has negative results such as cognitive overload and in that reason systematic approach is needed. This paper shows the factors on media selection and relationship to interface components. To select appropriate media to the needs and situation, it should be considered the user's ${\circled1}$background ${\circled2}$knowledge / frequency of use / expertise, contents ${\circled1}$task nature ${\circled2}$type of knowledge and media ${\circled1}$representation format ${\circled2}$interaction techniques. Varying the media factors and varying the expression factors offers concrete design features.

• Horticultural Science & Technology
• /
• v.17 no.3
• /
• pp.352-354
• /
• 1999

Randomly and specifically amplified polymorphic DNA band patterns based on polymerase chain reaction (PCR) analysis were used to assess genetic variation of somaclonal variants obtained from tissue culture of lisianthus (Eustoma grandiflorum). Five different types of variant were classified by morphological characters such as leaflet number, leaf shape, caulicle length, plant height, and leaf area. Five primers out of 20 primers (10 mer) resulted in 34 random amplified DNA fragments with polymorphisms (64.7%) in all tested plants. The dissimilarity coefficient was from 0.71 to 0.91 by UPGMA cluster analysis. Based on the presence of polymorphic bands, normal plant and five somaclonal variants were divided into two groups at the similarity coefficient value of 0.79.

• Horticultural Science & Technology
• /
• v.34 no.2
• /
• pp.294-304
• /
• 2016

Members of the genus Brassica, which are known as oil crops or cruciferous vegetables, are widely cultivated in Canada, Australia, Asian and Europe. Because Brassica species have high yields, are well adapted to their environments, and are self-incompatible, the germplasm is abundant. Previous studies have reported abundant genetic diversity even within Brassica subspecies. In Korea, fresh cabbage leaves are eaten with roast meat, and to meet the current popular demand, new varieties are being increasingly bred. To determine the genetic diversity and relationships among the cabbage vegetables in Korea, we evaluated the genetic variation of 18 accessions based on 5S and 18S ribosomal RNA (rRNA) gene sequences. We detected many variable nucleotide sites, especially in the 5S rRNA gene sequences. Because the length of the 18S rRNA gene might influence the dissimilarity rate statistics, we used both the 5S and 18S sequences to analyze the phylogenetic relationships. S7 (B. oleracea) showed the most distant phylogenetic relationship with the other Brassica species. Interestingly, B2 (B. oleracea), B15, and B18 (B. campestris) have three different types of leaf profiles, and were divided into one group, and the other Brassica species formed another group. Statistical analysis of interspecies and intraspecies genetic distances revealed that B. campestris L. showed higher genetic diversity than B. oleracea L. This work provides additional data that facilitates the evaluation of the genetic variation and relationships among Brassica species. The results could be used in functional plant breeding programs to improve Brassica crops.