• The Korean Journal of Mycology
• /
• v.46 no.4
• /
• pp.479-490
• /
• 2018

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70-100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, among which an isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and ${\beta}-tubulin$ nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

• Journal of Life Science
• /
• v.28 no.12
• /
• pp.1529-1535
• /
• 2018

The number of antibiotic-resistant bacteria is increasing rapidly while the discovery rate of new antibiotics is in decline. A systematic study is therefore necessary to investigate which bacteria are resistant to medically important antibiotics and how high that resistance is. To that end, this study aimed to analyze which bacteria demonstrated resistance to ampicillin, one of the currently most-widely used medical antibiotics. Water samples were collected from the Changwon-Cheon that runs through Changwon City and from the pond in front of the dormitory building at Changwon University. Hundreds of ampicillin-resistant colonies were obtained and 22 morphologically distinct examples were chosen for further study. These bacteria were identified by amplifying their 16S rRNA genes and comparing those sequences with data in GenBank. The bacteria was identified as belonging to 10 families, 12 genera, and 17 species, and all were able to grow in the presence of $50{\mu}g/ml$ ampicillin while seven showed growth at ampicillin concentrations as high as 1.5 mg/ml.

• Korean Journal of Microbiology
• /
• v.55 no.3
• /
• pp.242-247
• /
• 2019

Biological factors (e.g. microorganism activity) in wastewater treatment plant (WWTP) play essential roles for degradation and/or removal of organic matters. In this study, to understand the microbial functional roles in WWTP, we tried to isolate and characterize a bacterial strain from activated sludge sample. Strain S16 was isolated from the activated sludge of a municipal WWTP in Daejeon metropolitan city, the Republic of Korea. The cells were a Gram-stain-positive, non-motile, facultative anaerobe, and rod-shaped. Strain S16 grew at a temperature of $15{\sim}40^{\circ}C$ (optimum, $30^{\circ}C$), with 0~9.0% (w/v) NaCl (optimum, 1.0~2.0%), and at pH 5.5~9.0 (optimum, pH 7.0~7.5). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S16 was most closely related to the unique species Miniimonas arenae NBRC $106267^T$ (99.79%, 16S rRNA gene sequence similarity) of the genus Miniimonas. The cell wall contained alanine, glutamic acid, serine, and ornithine. Although the isolation source of the type strain NBRC $106267^T$ which considered as a marine microorganism is sea sand, that of strain S16 is terrestrial environment. It might raise an ecological question for habitat transition. Therefore, comparative genome analysis will be valuable investigation for shedding light on their potential metabolic traits and genomic streamlining.

• Journal of Korean Society of Forest Science
• /
• v.108 no.3
• /
• pp.302-310
• /
• 2019

Precise and fast identification of crop cultivars is essential for efficient breeding and plant breeders' rights. Traditional methods for identification of jujube cultivars are based on the evaluation of morphological characteristics. However, due to time constraints and environmental influences, it is difficult to distinguish cultivars using only morphological traits. In this study, we cloned fragments from improved inter simple sequence repeats (ISSR) analysis, and developed stably diagnostic sequence-characterized amplified region (SCAR) markers. The specific ISSR bands of jujube cultivars from Dalizao and Boeundaechu were purified, cloned, and sequenced. As a result, four clones labeled 827Dalizao550, 827Boeun750, 846Boeun700, and 847Dalizao850 were identified. In order to investigate whether they were specific for the jujube cultivar, four pairs of SCAR primers were then designed and polymerase chain reaction (PCR) amplifications were conducted to analyze 32 samples, including jujube and sour jujube. In the PCR amplification of the 827Dalizao550 SCAR marker, the specific bands with 550 bp were amplified in six samples (Dalizao, Sandonglizao, Dongzao, Yuanlin No. 2, Suanzao 2, Suanzao 4), but unexpected bands (490 bp) were amplified in the others. Moreover, in the PCR amplification of the 847Dalizao850 SCAR marker, the specific bands with 850 bp were found in three samples (Dalizao, Sandonglizao, and Dongzao) and 900 bp unexpected bands were amplified in five samples (Pozao, Suanzao 1, Suanzao 2, Suanzao 3, Suanzao 4). These results showed that newly developed markers could be useful as a fast and reliable tool to identify jujube cultivars. However, further identification of polymorphic information and the development of SCAR markers are required for the identification of more diverse cultivars.

• Research in Plant Disease
• /
• v.25 no.1
• /
• pp.16-21
• /
• 2019

Botrytis cinerea is the pathogen for a gray mold generating problems during the cultivation and transportation of roses. But there is little information about the difference of the symptom severity caused by gray mold on rose varieties and pathogen strains. 16 strains were collected from the rose cultivation area to confirm the degree of disease occurrence against strains and each variety. Collected 16 strains were identified based on the sequences analysis of ITS region of ribosomal DNA by using specific primers. The sequence analysis was performed by comparing the sequences to find a difference. To confirm the difference in disease occurrence for each strains, the difference was classified from 0 to 5 stages using charmant variety as a control. The data was confirmed through Kruskal-Wallis ANOVA. The result showed the significant difference in the pathogenicity caused by strains. WNG6_5 showed the lowest pathogenicity with 0.24 and WNG6_3 showed the highest with 3.20. The difference between two strains were almost 3.0. In addition, nine varieties of roses were more investigated with three strains such as the strains of WNG6_5, Hwa_1, and WNG6_3. The result showed that the Love Letter variety showed resistance and the Ice Bear variety was sensitive to three strains. Taken together, this study showed the significant difference by the interactions of rose varieties and gray mold strains.

• Korean Journal of Microbiology
• /
• v.54 no.4
• /
• pp.428-435
• /
• 2018

In this study, we isolated and identified bacteria from freshwater and soil collected from Osang reservoir, to screen antimicrobial bacteria against various pathogenic bacteria. 38 strains were isolated and assigned to the class Proteobacteria (22 strains), Actinobacteria (7 strains), Bacteroidets (6 strains), and Firmicutes (3 strains) based on 16S rRNA gene sequence analysis. Among them, strain OS17 showed a good growth inhibition against 5 methicillin-resistant Staphylococcus aureus subsp. aureus strains and Bacillus cereus, Bacillus subtilis, Filobasidium neoformans. As a result of the 16S rRNA gene sequence analysis, strain OS17 show the high similarity with Burkholderia ambifaria $AMMD^T$, B. diffusa $AM747629^T$, B. tettitorii $LK023503^T$ 99.8%, 99.7%, 99.6%, respectively. We investigated cell growth and antimicrobial activity according to commercial culture medium, temperature, pH for culture optimization of strain OS17. Optimal conditions for growth and antimicrobial activity in strain OS17 were found to be: YPD medium, $35^{\circ}C$ and pH 6.5. When the strain was cultured in LB, NB, TSB, R2A media at $20^{\circ}C$ and $25^{\circ}C$, the antimicrobial activity did not show. Culture filtrate of strain OS17 showed antimicrobial activity against 5 MRSA strains, Bacillus cereus, Bacillus subtilis, and Filobasidium neoformans with inhibition zones from 2 to 8 mm. Optimal reaction time was 48 h in YPD medium, 100 rpm and 0.3 vvm in 2 L-scale fed-batch fermentation process for antimicrobial activity. Culture optimization of strain OS17 can be improved on antimicrobial activity. Therefore, the antimicrobial activity of Burkholderia sp. OS17 had potential as antibiotics for pathogens including MRSA.

• Korean Journal of Ichthyology
• /
• v.33 no.3
• /
• pp.184-190
• /
• 2021

Since the original description of new species, Eumicrotremus jindoensis, we confirmed the first occurrence of E. jindoensis based on a single specimen (22.3 mm SL) caught by inshore stow net at the coastal waters of Boryeong of Korea. However, our specimen slightly differed from type specimens in having more vertebrae (26 vs. 21~24), longer snout (17.4% vs. 8.1~9.1%), longer preanus length (67.5% vs. 58.0~58.3%) and shorter second dorsal fin base (15.3% vs. 20.2~20.8%). Comparing with mtDNA COI and Cytb sequences, we could not find any differences in mtDNA Cytb sequences between our specimen and type specimens, which suggest that those morphological differences may belong to local variation by habitat and environmental condition between off Jindo Island and off Boryeong in Korea. Eumicrotremus uenoi is known from the southern sea of Korea narrowly (Busan, Tongyeong, and Jeju Island), the other congeneric species (E. asperrimus, E. pacificus, and E. taranetzi) from only the eastern sea of Korea, but E. jindoensis from the central coast to southern coast of western Korea.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.29 no.3
• /
• pp.27-33
• /
• 2021

CO I gene sequence analysis was applied to earthworms that had been used as test animals in toxicity test in Institute of Kyeongbook Agrochemicals and earthworms used as vermicomposting agents in the farm of Youngdong province to identify their species names. In terms of molecular species, the former was identified as Eisenia fetida and the latter was Eisenia andrei. Cocoons produced from Eisenia fetida was more than those from Eisenia andrei. And No. of adults developed from eggs of Eisenia fetida was more or less higher than those developed from eggs of Eisenia andrei. These results were contradictory to previous reports on two Eisenia spp.. When Eisenia fetida was crossed with Eisenia andrei, hybridized eggs were produced and adults were developed from those eggs, but cocoons and adults were much less than those from non-crossed Eisenia fetida or Eisenia andrei. This indicated that two Eisenia spp. were not distinctly different biological species because there was no complete 'reproductive isolation' between Eisenia fetida and Eisenia andrei. However, this also meant that Eisenia fetida and Eisenia andrei had already been on the tract of speciation.

• The Korean Journal of Mycology
• /
• v.48 no.4
• /
• pp.475-484
• /
• 2020

Various indigenous yeasts were isolated and obtained from flowers in the Republic of Korea, and their distribution and species diversity were studied. Seventy-seven flowers were collected from 25 areas in Korea, and 502 yeast strains were isolated from these flowers. A total of 50 species were identified by comparing large subunit rDNA gene sequence homology with the type strains of yeasts. The analysis of yeast distribution showed that the dominant yeast species were Aureobasidium pullulans, A. leucospermi, and Filobasidium magnum in each region and flower samples. Except for the above three yeast species, no species of yeasts showed any meaningful distribution among the habitat regions and sources. In conclusion, 50 species of indigenous yeasts were obtained from flowers that can be used as industrial resources, and the data could be used for further research on yeast diversity and interactions between yeast and its host.

• 한국사회정책
• /
• v.23 no.2
• /
• pp.141-172
• /
• 2016

This study examines the employment conditions and labour experience of elementary after-school care teachers in South Korea. Based on the empirical data collected through in-depth interviews with after-school care teachers in Gwangju Metropolitan City, the study considers multifaceted problems faced by after-school care teachers in their workplace. The after-school care class is part of educational policies initiated and rapidly expanded by the Ministry of Education, resulting in the substantial increase of non-regular school workers. The irregularization of after-school care teachers illustrates that the common problems faced by female non-regular workers, such as social discrimination, exclusion and inequality, are also transplanted into the typical public sector. In the case of Gwangju Metropolitan City, during the past two years there have been evident increases both in under 15-hour short time contract care teachers and outsourcing of care classes. Temporary part-time contract care teachers suffer relentless job insecurity and experience poor working conditions, exclusion and discrimination within the workplace and labour alienation. In order to minimize the organized resistance of care teachers, school authorities implicitly individualize and isolate care teachers through hierarchization, the division of labour and the spatial division of classes between indefinite and temporary contract teachers.