• Journal of Ecology and Environment
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• v.31 no.4
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• pp.309-316
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• 2008

To develop a monitoring method for soil microbial communities in rice paddy fields, we used terminal restriction fragment length polymorphism (T-RFLP) to compare soil bacterial community structure in rice paddy fields experiencing different management practices: organic practices, conventional practices without a winter barley rotation, and conventional practices with a winter barley rotation. Restriction fragment length profiles from soils farmed using organic practices showed very different patterns from those from conventional practices with and without barley rotation. In principal component analyses, restriction fragment profiles in organic practice samples were clearly separated from those in conventional practice samples, while principal component analysis did not show a clear separation for soils farmed using conventional practices with and without barley rotation. The cluster analysis showed that the bacterial species compositions of soils under organic practices were significantly different from those under conventional practices at the 95% level, but soils under conventional practice with and without barley rotation did not significantly differ. Although the loadings from principal component analyses and the Ribosomal DNA Project II databases suggested candidate species important for soils under organic farming practices, it was very difficult to get detailed bacterial species information from terminal restriction fragment length polymorphism. Rank-abundance diagrams and diversity indices showed that restriction fragment peaks under organic farming showed high Pielou's Evenness Index and the reciprocal of Simpson Index suggesting high bacterial diversity in organically farmed soils.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.788-797
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• 2001

The usefulness of three PCR methods were evaluated for the epidemiological typing of Staphylococcus aureus: an enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), repetitive extragenic palindromic element PCR (REP-PCR), and 16S-23S intergenic spacer PCR (ITS-PCR). The analysis was performed using a collection of S. aureus strains comprised of 6 reference and 79 isolates from patients with various diseases. Among the 85 S. aureus strains tested, 6 references and 6 isolates were found to be susceptible to methicillin, whereas the remaining 73 isolates were resistant to it. PCR methods are of special concern, as conventional phenotypic methods are unable to clearly distinguish among methicillin-resistant S. aureus (MRSA) strains. The ability of the techniques to detect different unrelated types was found to be as follows: ERIC-PCR, 19 types; REP-PCR, 36 types; and ITS-PCR, 14 types. On the basis of combining the ERIC, REP, and ITS fingerprints, the 85 S. aureus strains were grouped into 56 genetic types (designated G1 to G56). The diversities for the 85 S. aureus strains, calculated according to Simpson\`s index, were 0.88 for an ERIC-PCR, 0.93 for a REP-PCR, and 0.48 for an ITS-PCR, and the diversity increased up to 0.97 when an ERIC-PCR and REP-PCR were combined. The above discrimination indices imply that the genetic heterogeneity of S. aureus strains is high. Accordingly, this study demonstrates that DNA sequences from highly conserved repeats of a genome, particularly a combination of ERIC sequences and REP elements, are a convenient and accurate tool for the subspecies-specific discrimination and epidemiologic tracking of S. aureus.

• Spatial Information Research
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• v.3 no.1
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• pp.47-53
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• 1995

The weed survey in lowland rice fields through Korea was conducted in 1992 to determine a change of the weed communities based on different regions, soil types, planting methods, and cultural practices. GIS was applied to identify a spatial analysis of predominant weed species in specific region. On behalf of vegetatine analysis such as absolute and relative density, absolute and relative frequency, importance value, and summed dominance ratio(SDR), there was highly dominant with a perennial weed species, Eleocharis kuroguwai Ohwi over whole country. However, in particular it was most predominant at southem area of Gyunggi province in Korea. Thus, rice farmers of this area have to introduce a specific comperhensive control strategy against this predominant weed species.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.11-18
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• 1984

The effect of transplanting method of rice seedlings on weed occurrence was investigated at the Yeongnam Crop Experiment Station in 1983. Rice was transplanted by hand and machine and eleven common herbicides were applied. The greatest weeds were harvested from the plot that rice was not transplanted and more weeds encountered at machine transplanted plot than hand transplanted plot. The degree of weed suppression by rice plant itself was 50% for machine transplatning and 55% for hand transplanting, respectively. Simpson index and community dominance of weed species were the highest in hand transplanting and followed by machine transplanting and no rice plot in order. Rice grain yield was exponentially correlated with the amounts of weed occurrence and more yield loss exhibited at machine transplanting than hand transplanting in the same amount of weeds. In the herbicidal activity, most of herbicides performed better at hand transplanting than machine transplanting while the degree of difference between transplanting methods varied depend on herbicide used.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.63-68
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• 1998

This experiment was carried out to select some herbicides for edible wild greens, Album monanthum, Petasites japonicus, and Aster scaber. The herbicides tested were napropamide 21.8% EC, nitralin 50% WP, and pendimethalin 31.7% EC. Dorminant weeds in the field were Echinochloa crus-galli, Digitaria sanguinalis, Persicaria hydropiper, Chenopodium album, and Siegesbeckia pubescens. Simpson's index was calculated to 0.26~0.30, which showed that weed occurrence in the field was quite various. Control efficacy in the field treated with napropamide EC 872g(ai/ha)., nitralin WP 1,000g(ai/ha), and pendimethalin EC 634g(ai/ha) were 81.4%~85.6%, 79.4%~82.8%, and 86.8%~92.2%, respectively. The typical phytotoxic symptoms to herbicides were germination inhibition, growth retardation, and malformation.

• Korean Journal of Environment and Ecology
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• v.27 no.2
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• pp.196-203
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• 2013

Butterfly communities were monitored to investigate the emergence pattern with line transect method at Wolchulsan National Park through May to October in 2012. Totally 1,151 individuals belong to 49 species were monitored through the study period. Libythea celtis was a dominant species with showing 357 individuals(31%) followed by Pseudozizeeria maha 96 individuals(8.3%), Mycalesis gotama 75 individuals(6.5%) and Ninois dryas 72 individuals(6.2%) respectively. Among the monitoring periods, highest individuals and species(516 individuals belong to 30 species) were found at June and showed a high abundance near reservoir region. Highest diversity was shown at August with a Shannon index of 2.75 while lowest at October(Shanon index 1.78) and total diversity index was 1.71. Dominance values(Simpson index) showed highest at June with a value of 0.40 while lowest at September with a value of 0.07 and averaged 0.12. Kungol and Seongjeon compose a high similarity habitats with a similarity value of 0.52 and it was 0.17 at Kungol and Youngsan, lowest cases. Reservoir banks played a important role for habitats of specific species. It can be considered that they provide an open space of glass land for butterfly population, which was deficient at mountain area.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.146-159
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• 2020

The objective of our study was to analyze the distribution and composition of fish species and their community characteristics in agricultural waterways in the six water systems-Mankyung River, Seomjin River, Namhae Region, Tamjin River, Yeongsan River, and Dongjin River-during 2017-2018. Little is known about the distributions and community characteristics of the aquatic biota of agricultural waterways in Korea, even if the water bodies have important roles as spawning areas or habitats for fish. In this study, we identified 3,633 fish individuals in the waterways, belonging to 53 species, eleven families, and six orders (dominant species: Tanakia koreensis, T. lanceolate) and 7,108 fish individuals in the main rivers, belonging to 57 species, fifteen families, and nine orders. Moreover, three endangered wildlife (designated by the Ministry of Environment, Korea)-T. somjinensis, Acheilognathus majusculus and Coreoperca kawamebari-were found in the waterways. By fish guild analysis, we found that many waterways had a lower proportion of sensitive species and a higher proportion of omnivore species than those of the main rivers, which indicates a feature of a disturbed environment. In addition, by grouping with environmental variables, we found the group of waterways with high substrate complexity had a higher diversity index (Shannon index) and a lower dominance index (Simpson index) than that of simple substrate complexity. Overall, our study represents the characteristics of fish habitats in agricultural waterways and suggests the need to manage them and study further.

• Journal of Life Science
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• v.26 no.12
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• pp.1446-1457
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• 2016

Wetlands exhibit intermediate characteristics of both terrestrial and aquatic ecosystems, and the biodiversity is rich in these unique biological habitats. The symbiotic relationships between plants and fungi that inhabit these wetlands play an important role in natural resource management, biodiversity, and conservation. Accordingly, the mujechi, having academic value for the study of the natural environment, was investigated in terms of genetic diversity of endophytic fungi, which inhabit the roots of wild plants. The internal transcribed spacer (ITS) region was amplified to identify fungal strains. In total, 226 strains were isolated and categorized into three phyla, seven classes, 10 orders, 22 families, and 31 genera. In plants by endophytic fungi were classified in Isachne globosa (Ig) to 19 genera, Scirpus karuisawensis (Sk) to 11 genera, Utricularia racemosa (Ur) to 19 genera, and one incertae sedis, Eriocaulon decemflorum (Ed) to 11 genera. The fungal taxa was identified the genera Acephala (19.9%), Tolypocladium (16.3%), Neopestalotiopsis (11.5%), and Perenniporia (7.1%). The fungal group isolated from Isachne globosa (Ig) grew the largest number of isolated fungal strains. After comprehensive evaluation, the endophytic fungal group from Utricularia racemosa (Ur) ranked highest in diversity analyses. From the roots of wild plant in mujechi-neup, it confirmed the distribution and diversity of endophytic fungi. This study provides the basic data to understand fungal community structure in peat wetlands.

• Mycobiology
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• v.45 no.3
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• pp.160-171
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• 2017

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

• Mycobiology
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• v.46 no.2
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• pp.85-91
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• 2018

Endophytic fungi strains (n = 81) were isolated from the leaves, barks, and fruits of Camellia oleifera from Hunan province (China) to delineate their species composition and potential as biological control agents of C. oleifera anthracnose. The fungi were identified by morphological and phylogenetic analyses. Fungal colonization rates of the leaves, barks, and fruits were 58.02, 27.16, and 14.81%, respectively. The isolates were identified as 14 genera, belonging to two subdivisions, Deuteromycotina and Ascomycotina; 87.65% of all isolates belonged to Deuteromycotina. The dominant species, occurring with a high relative frequency, were Pestalotiopsis sp. (14.81%), Penicillium sp. (14.81%), and Fusarium sp. (12.35%). The Simpson's and Shannon's diversity indices revealed the highest species diversity in the leaves, followed by the barks and fruits. The similarity index for the leaves versus barks comparison was the highest, indicating that the number of endophytic fungal species shared by the leaves and barks was higher than barks and fruits or leaves and fruits. Based on the results of dual culture experiments, only five strains exhibited antifungal activity against C. oleifera anthracnose pathogen, with isolate ty-64 (Oidium sp.) generating the broadest inhibition zones. Our results indicate that the endophytes associated with C. oleifera could be employed as natural agents controlling C. oleifera anthracnose.