• The Plant Pathology Journal
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• 제31권2호
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• pp.152-164
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• 2015

Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and $YC7010^T$, with antimicrobial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension ($10^7cfu/ml$) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC $15859^T$ (99.67%), Bacillus methylotrophicus KACC $13105^T$ (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC $17177^T$ (99.60%), and Bacillus tequilensis KACC $15944^T$ (99.45%). The DNA-DNA relatedness value between strain $YC7010^T$ and the most closely related strain, B. siamensis KACC $15859^T$ was $50.4{\pm}3.5%$, but it was $91.5{\pm}11.0%$ between two strains YC7007 and $YC7010^T$, indicating the same species. The major fatty acids of two strains were anteiso-$C_{15:0}$ and iso $C_{15:0}$. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC7007 and $YC7010^T$ represent novel species of the genus Bacillus, for which the name Bacillus oryzicola sp. nov. is proposed. The type strain is $YC7010^T$ (= KACC $18228^T$). Taken together, our findings suggest that novel endophytic Bacillus strains can be used for the biological control of rice diseases.

• 한국과학교육학회지
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• 제32권10호
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• pp.1537-1550
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• 2012

이 연구 목적은 한국과 미국 대학생들을 대상으로 진화 개념과 관련된 변인-종교성, 진화 흥미, 진화 개념, 진화 수용-에 관한 수준과 구조적 차이를 비교 분석하는 것이다. 이 연구를 위하여 한국과 미국 대학생 1,015 학생이 참여하였으며 그 중 무작위로 추출된 516명의 자료가 분석에 활용되었다. 연구 결과 한국의 대학생들은 미국의 대학생들에 비하여 낮은 종교성을 보이는 반면 진화 흥미 역시 낮았다. 경로 분석결과 종교성이 진화 수용에 미치는 인과관계에서 진화 개념과 진화 흥미가 매개함을 알 수 있었다. 한국 대학생들은 미국 대학생들에 비하여 진화 흥미가 종교성, 진화 수용, 진화 개념과 상대적으로 낮은 수준의 관련성을 보였다. 한국의 생물 전공자들의 진화 수용은 미국 생물 전공자들의 비하여 진화 개념에 대한 영향력이 적었고, 한국 생물 비전공자들의 진화 수용은 미국 생물 비전공자들에 비하여 종교성에 더 큰 영향을 받았다. 이 연구 결과는 한국 학생들을 위한 진화 교육이 진화론에 대한 흥미를 더 높이며, 진화론을 수용함에 있어 개인의 종교적 신념에 근거하지 않고 과학적 이론으로 수용할 수 있어야 함을 보여준다. 또한 우리나라 대학생들이 과학적 판단에 의하여 과학 이론을 수용하는 태도를 함양시킬 수 있는 과학교육이 필요하다.

• 한국과학교육학회지
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• 제29권7호
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• pp.767-782
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• 2009

The researchers who are studying biology and teachers who are teaching biology think that the genetics-related concepts are highly significant than other concepts in biology. With such background, researches on the identification of major concepts have been under way to guide in biology class. Minimal research has been carried out, however, on what concepts should be taught to achieve the specific objectives of the class in relation to the unit of genetics in middle and high school. Accordingly this study was designed to determine the concepts of genetics that should be taught to achieve the objectives of the genetics unit in secondary school. For this purpose 5 instructional objectives of the genetics unit on the 9th grade and 4 instructional objectives of Biology I were selected and the concepts that were taught to achieve class objectives. The survey was conducted among 114 science teachers from middle schools and 85 biology teachers from high schools. The results indicated that 9.1 and 10.2 concepts on average were taught in the 9th grade and in Biology I respectively. Moreover statistical difference in the number of concepts that were taught according to the teachers' teaching experiences appeared among the middle school teachers (p<.05). But such statistical difference did not appear among the high school teachers (p>.05). Furthermore the concepts for the 9th grade consist of the basic genetics concepts although Biology I concepts were integrated and advanced contents for same concepts. Thus this finding suggests that concepts of genetics units to be taught in middle and high school were in linkage.

• 생태와환경
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• 제42권4호
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• pp.476-486
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• 2009

Major objective of our study was to introduce initial researches of national long-term ecological monitoring studies on Daechung Reservoir, as one of the representative lentic reservoir ecosystems in Korea. For the long-term ecological research (LTER), we conducted preliminary field monitoring during 2008~2009 and analyzed biological parameters such as phytoplankton, zooplankton, and freshwater fish along with chemical water quality and empirical model analysis. According to phytoplankton surveys, major taxa have varied largely depending on seasons and sites sampled. Overall phytoplankton data showed that cyanophyta dominated in the summer period and diatoms dominated in the winter. In zooplankton analysis, 25 species including 20 rotifers, 3 cladocerans and 2 copepods were collected during the survey. The relative abundance of rotifers (86.5%) was always greater than that of cladocerans (6.3%) or copepods (5.1%). There were distinct spatial and inter-annual changes in the abundance of zooplankton in the reservoir, displaying similar patterns in three sites with the exception of S3 during the study. According to fish surveys, 8 families and 39 species were observed during 2008~2009. The most dominant fish was an exotic species of Lepomis macrochirus (23%), indicating an severe influence of exotic species to the ecosystem. TP averaged $17.9\;{\mu}g\;L^{-1}$ ($6{\sim}80\;{\mu}g\;L^{-1}$), which was judged as a mesotrophy, and showed a distinct longitudinal gradients. TN averaged $1.585\;{\mu}g\;L^{-1}$ during the study and judged as hypereutrophic condition. Unlike TP, TN didn't show any large seasonal and spatial variations. Under the circumstances, nitrogen limitation may not happen in this system, indicating that nitrogen control is not effective in the watershed managements. These data generated in the LTER station will provide key information on long-term biological and water quality changes in relation to global warming and some clues for efficient reservoir ecosystem managements.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.201-207
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• 2011

Peroxisome proliferator-activated receptors (PPARs) are members of nuclear receptors and their activation induces regulation of fatty acid storage and glucose metabolism. Therefore, the $PPAR\gamma$ is a major target for the treatment of type 2 diabetes mellitus. In order to generate pharmacophore model, 1080 known agonists database was constructed and a training set was selected. The Hypo7, selected from 10 hypotheses, contains four features: three hydrogen-bond acceptors (HBA) and one general hydrophobic (HY). This pharmacophore model was validated by using 862 test set compounds with a correlation coefficient of 0.903 between actual and estimated activity. Secondly, CatScramble method was used to verify the model. Hence, the validated Hypo7 was utilized for searching new lead compounds over 238,819 and 54,620 chemical structures in NCI and Maybridge database, respectively. Then the leads were selected by screening based on the pharmacophore model, predictive activity, and Lipinski's rules. Candidates were obtained and subsequently the binding affinities to $PPAR\gamma$ were investigated by the molecular docking simulations. Finally the best two compounds were presented and would be useful to treat type 2 diabetes.

• Parasites, Hosts and Diseases
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• 제61권1호
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• pp.60-71
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• 2023

Cockroaches can cause allergic sensitization in humans via contact with their feces or frass. Antibiotics can affect concentration of major allergen and total bacteria production in German cockroaches (Blattella germanica). This study examined the ability of antibiotic-treated German cockroaches to induce allergic airway inflammation and the effect of antibiotics on their lipopolysaccharide and Bla g1, 2, and 5 expression levels. Specifically, we measured the ability of German cockroach extract (with or without prior antibiotic exposure) to induce allergic inflammation in human bronchial epithelial cells and a mouse model of asthma. Bacterial 16S rRNA and lipopolysaccharide levels were lower in ampicillin-treated cockroaches than in the control group. The Bla g1, Bla g2, and Bla g5 expression in ampicillin-treated cockroaches decreased at both the protein and RNA levels. In human bronchial epithelial cell lines BEAS-2B exposed to the ampicillin-treated extract, expression levels of interleukin-6 and interleukin-8 were lower than that in the control group. The total cell count and eosinophil count in bronchoalveolar lavage fluid was also lower in mice exposed to the ampicillin-treated extract than in those exposed to normal cockroach extract. Mouse lung histopathology showed reduced immune cell infiltration and mucus production in the ampicillin group. Our results showed that ampicillin treatment reduced the symbiont bacterial population and major allergen levels in German cockroaches, leading to reduced airway inflammation in mice. These results can facilitate the preparation of protein extracts for immunotherapy or diagnostics applications.

• BMB Reports
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• 제28권6호
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• pp.546-551
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• 1995

The conformation studies of myelin P2 protein and two of its major peptides were carried out using circular dichroism and fluorescence spectroscopy in water and in lipid environments. Significant conformational changes occur when the protein or peptides were bound to gangliosides. Similar effects were also found in trifluoroethanol solutions. The conformational features of P2 protein and its major peptides were discussed in relation to the environmental changes and the disease-inducing effects.

• Journal of Ecology and Environment
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• 제36권2호
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• pp.125-129
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• 2013

The study on the major insect pests community of Hibiscus syriacus. There were three orders, seven families, and thirteen species of insects harmful to H. syriacus. When the harmful insects eating H. syriacus were classified according to which part of the flower they were eating, insects eating leaves, which considered of nine species four families and one order, accounted for 69.23 %. Insects sucking juice from leaves and stems comprised 15.38 %, with two species two families and two orders, while insects eating seeds comprised 15.38 %, with two species two families and two orders. Aphis gossypii appeared once per H. syriacus from the fourth week of April to the second week of June, appearing the most at a rate of 69.05 per H. syriacus during the first week of May. Dichocrocis surusalis appeared at a rate of 0.05 per H. syriacus during the third week of April and regularly appeared from the first week of July to the second week of September. Nortacha derogata appeared at a rate of 0.1 per tree during the first week of May, after which it continuously appeared until the third week of October. Anomis privata appeared at a rate of 0.05 per tree during the first week of May and continuously occurred from the fourth week of June to the fourth week of October. Its occurrence was most frequent at 2.30 per tree during the third week of September.

• Advances in environmental research
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• 제6권2호
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• pp.127-137
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• 2017

Cotton is the major fiber crop in Pakistan that accounts for 2% of total national gross domestic product (GDP). After picking of cotton, the dry stalks are major organic waste that has no fate except burning to cook food in villages. Present research focuses use of cotton stalks as feedstock for biochar production, its characterization and effects on soil characteristics. Dry cotton stalks collected from agricultural field of Bahauddin Zakariya University, Multan, Pakistan were combusted under anaerobic conditions at $450^{\circ}C$. The physicochemical analysis of biochar and cotton stalks show higher values of % total carbon, phosphorus and potassium concentrations in biochar as compared to cotton stalks. The concentration of nitrogen was decreased in biochar. Similarly biochar had greater values of fixed carbon that suggest its role for carbon sequestration and as a soil amendment. The fourier transformation infrared spectroscopic spectra (FTIR) of cotton stalks and biochar exposed more acidic groups in biochar as compared to cotton stalks. The newly developed functional groups in biochar have vital role in increasing surface properties, cation exchange capacity, and water holding capacity, and are responsible for heavy metal remediation in contaminated soil. In a further test, results show increase in the water holding capacity and nutrient retention by a sandy soil amended with biochar. It is concluded that cotton stalks can be effectively used to prepare biochar.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권2호
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• pp.137-142
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• 2007

The antibacterial activity of Korean honey bee venom (KBV) was examined against seven major bacterial mastitis pathogens, Enterococcus faecium, Escherichia coli, Methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus intermedius, Streptococcus oralis and Streptococcus uberis isolated from infected mammary quarters of cows. Seven bacterial mastitis pathogens were studied for antibacterial activity of the KBV by disc diffusion assay, minimal inhibitory concentrations (MIC) and bacterial count in milk samples. The KBV showed activity against Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius. The order of susceptibility of the bacteria against the KBV was Staph. aureus>MRSA>E. coli>Strep. intermedius>Ent. faecium>Strep. oralis>Strep. uberis. The MIC against Staph. aureus, MRSA and E. coli were stronger effect as compared with standard drug. The effect of the KBV ($100{\mu}g\;ml^{-1}$) on the viability of Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius, Strep. oralis and Strep. uberis in milk differed significantly with each other within 12 h incubation period. The results indicate that KBV has significant antibacterial effects against major bacterial mastitis bacteria, Ent. faecium, E.coli, MRSA, Staph. aureus, Strep. intermedius. Results of the study indicate the potential use of KBV as alternative to antibiotic therapy. Further investigations are needed though to confirm its efficacy and its effects on the animals.