• Title/Summary/Keyword: growth and activities

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A Comparison of Radical Scavenging Activity and Cyanobacteria Growth Inhibition of Aquatic Vascular Plants (수생관속식물의 라디칼 소거능과 남세균 생장에 대한 억제활성 비교)

  • Kwon, Sung-Ho;Na, Hye-Ryun;Jung, Jong-Duk;Baek, Nam-In;Park, Sang-Kyu;Choi, Hong-Keun
    • Korean Journal of Ecology and Environment
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    • v.45 no.1
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    • pp.11-20
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    • 2012
  • Methanol extracts of aquatic plants were analyzed for allelopathic activities against Escherichia coli JM109 and $Microcystis$ $aeruginosa$ UTEX2385 which were compared to its 2,2-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. The radical scavenging activities were detected from the extracts of $Persicaria$ $thunbergii$, $Persicaria$ $amphibia$, $Trapa$ $japonica$, $Myriophyllum$ $spicatum$, and $Brasenia$ $schreberi$. Also, the inhibitory activities against cyanobacteria were analyzed according to the order of $B.$ $schreberi$, $T.$ $japonica$, $P.$ $amphibia$, and $M.$ $spicatum$. Most of the extracts from aquatic plants did not show any inhibition against $E.$ $coli$ except $B.$ $schreberi$. We found a positive correlation between the antioxidental activities of methanol extract of aquatic plants and the growth inhibitory activities for cyanobacteria in terms of the DPPH radical scavenging activities ($R^2$=0.381, $P$ <0.0001). The inhibitory activities of methanol extract against $E.$ $coli$ growth was not correlated with the other activities of aquatic plants ($P$ >0.04). We suggest from this study that the allelopathic effects of aquatic plants against cyanobacteria could be screened by using the bioassay based on DPPH.

Pre-service Early Childhood Teachers' Experiences of Participation in Major-associated Autonomous Club Activities (예비 보육교사의 전공 자율동아리 참여 경험의 의미)

  • Oh, Saenee;Yang, Jiae
    • Korean Journal of Childcare and Education
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    • v.18 no.1
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    • pp.71-90
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    • 2022
  • Objective: This study examined the experiences of pre-service Early Childhood teachers who participated in major-associated autonomous club activities. Methods: Participants were 31 students of the Department of Child Care at A University located in Gyeonggi-do, who participated in a major-associated autonomous music club activity. A content analysis was conducted to examine the meaning of the participation experience of pre-service Early Childhood teachers. Qualitative content analysis was the best method to analyze the meaning of their experience while participating in the activities. Results: The meaning of the experience of music club activities was organized into three categories: "enjoying abundant college life," "growing as a competent childcare teacher," and "being a responsible member of a community." Conclusion/Implications: The results show that pre-service Early Childhood teacher's participation in the activities of major-associated autonomous clubs has a positive impact on desirable changes in college life and adaptation to the department and on the growth of future professional Early Childhood teachers.

Relationships between Structural Features and Biological Activities of HC-toxin

  • Kim, Shin-Duk
    • BMB Reports
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    • v.28 no.3
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    • pp.227-231
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    • 1995
  • In order to figure out the relationships between structural features and biological activity of the host-specific HC-toxin in maize, structurally related cyclic tetrapeptides, chlamydocin and CYL-2 were isolated, and their biological activities in maize were examined. Biological activities of preparations were determined by root growth inhibition and electrolyte leakage bioassays. Chlamydocin and CYL-2 showed toxicities to maize. However, the toxicities of these compounds were non-specific. Thus, the precise peptide ring structure of HC-toxin apparently does not play an important role in toxicity, while resistance of maize to HC-toxin is based on a precise ring conformation.

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Understanding Organizational Characteristics in UK SMEs; The Factors and R&D

  • Hwang, In-Pyo
    • Journal of Technology Innovation
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    • v.7 no.2
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    • pp.71-100
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    • 1999
  • This article is concerned with the importance of organisation management and its characteristics in business performance in SMEs, and tested by four main aspects: managerial strategies, organisational structure, leader behaviour, and R&D activities. These relationships were tested with questionnaire data from a random sample of 87 firms. Results from simple statistics on each issue showed that SMEs have focused on the corporate growth and management goals, the democratic leadership, decentralisation in organisational structure, and the technology development plans. Results from correlation analyses not only found significant relationships between managerial strategy and R&D activities but also showed differences in R&D activities according to structural status or leadership style, respectively.

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Regulation of Tylosin Biosynthesis by Cell Growth Rate in Streptomyces fradiae (Streptomyces fradiae에서 균 성장속도에 의한 tylosin 생합성 조절)

  • 강현아;이정현;이계준
    • Korean Journal of Microbiology
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    • v.25 no.4
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    • pp.353-359
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    • 1987
  • The aim of the present study was to investigate the effects of growth rate on the biosynthesis of tylosin in Streptomyces fradiae. In order to elucidate the relation between the growth rate and the tylosin formation rate, the activities of enzymes involved in oxaloacetate metabolism were determined using cells grown at different growth rates in chemostats. As the results, it was found that the specific rate of tylosin formation($q_{p}$) was closely related to the specific cell growth rate and the maximum value of $q_{p}$ was 1.1mg tylosin, $q_{p}$ cell, $0.013h^{-1}$ at the growth rate $0.013h^{-1}$. However further increase in the growth rate over $0.013h^{-1}$ resulted in apparent decrease of $1_{p}$. The synthesis and activities of citrate synthase, aspartate aminotransferase, and PEP carboxylase were very low at lower growth rate. On the other hand, the activity and synthesis of methylmalonyl-CoA carboxyltransferase was closely related to tylosin formation. Therefore it was concluded that tylosin formation was apparently controlled by the growth rate.

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Antimicrobial Activity and Bactericidal Activity of Caesalpinia sappan L. Extract (소목 추출물의 항균력 및 살균소독력)

  • Lee, Jin-Young;Min, Kyung-Jin
    • Journal of Environmental Health Sciences
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    • v.37 no.2
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    • pp.133-140
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    • 2011
  • Antimicrobial activity and bactericidal activity of Caesalpinia sappan L. extracts were investigated against five food-borne pathogens, E. coli, S. aureus, S. typhimurium, B. cereus and L. monocytogenes. Methanol extract of Caesalpinia sappan L. revealed antimicrobial activities against five pathogens. In particular, by paper disc diffusion the highest activity was shown against L. monocytogenes. Antimicrobial activities of methanol extracts showed the most potent activities, but hexane fraction had no activity. Fractions of ethyl acetate and butanol turned out to have higher antimicrobial activities against Gram(+) bacteria than Gram(-) bacteria. The minimum inhibitory concentration against five food-borne pathogens was 1.563 mg/ml on Gram(+) bacteria and 3.125 mg/ml on Gram(-) bacteria. The result of antimicrobial activity in a shaking flask method showed that bacterial growth rate fell by more than 99.999% at 3.125 mg/ml of methanol extract. The highest rate of viable reduction (99.998%) was shown at 0.781 mg/ml of methanol extract against L. monocytogenes. After five minutes of reaction between test strains and methanol extracts, the growth rates of five kinds of bacteria were reduced by more than 99.999% at a concentration of 100 mg/ml. Therefore, it is suggested that methanol extracts of Caesalpinia sappan L. can be developed as a natural sanitizer or disinfectant.

Effects of Foliar Spray of CCC [(2-Chloroethyl)-trimethyl-ammonium Chloride] on the Growth of Mulberry Tree and Metabolic Activities in the Leaves. (CCC[(2-Chloroethyl) trimethyl-ammonium chloride]의 엽면살포가 상수의 생장 및 생체내 대사에 미치는 영향)

  • 이재와
    • Journal of Sericultural and Entomological Science
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    • v.22 no.1
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    • pp.46-51
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    • 1980
  • The effects of foliar Spray of CCC [(2-Chloroethyl)-trimethyl-ammonium Chloride] on the growth of mulberry tree and the metabolic activities in the leaves were measured. The results of this experiment are summarized as follows; 1. Foliar application of CCC was not effective in increasing of leaf area, the fresh and dry weight of the leaves and height of shoot, but was effective in increasing of diameter of Shoot. 2. Chlorophyll Content was generally increased in all treated leaves 3. All the treated leaves were lower in GOT and GPT activity than control leaves. 4. The activities of hydrolytic reducing Sugar in the mulberry leaves infiltrated Sucrose were lower than those of the control in all treated leaves, but the activities on Synthetic non-reducing Sugar in the mulberry leaves infiltrated glucose were higher than those of control in all treated leaves.

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Growth and Utility of Rhodiola sachalinensis in Baekdu Mountain II. Activities of Superoxide Dismutase in Portions of the Seedlings (백두산 자생참돌꽃의 생육과 이용 II. 유식물의 부위별 superoxide dismutase 활성)

  • So, Sang-Sup
    • Korean Journal of Environmental Biology
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    • v.26 no.4
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    • pp.349-354
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    • 2008
  • Superoxide dismutase (SOD) activities were investigated from the portions of shoots and roots in accordance with developmental stage and in response to environmental stress and antioxidants using Rhodiola-seedlings. The rates of SOD activities were revealed highly at the portion of roots and its tip of seedlings in the latter stages rather than the initial stages. SOD activities of seedlings in the initial stages treated with sodium chloride and cadmium as environmental stressors showed the decrease by 15 and 30% with respect to the control, respectively. However, in spite of stressor-treatments, the activities in the roots were increased according to the growth period showing a maximum rate of up to 45%. Also, SOD activities of the seedling treated with ascorbic acid as a antioxidant were increased by 46% of control value, but this was similar to the rate revealed in the presence of stressors. These results suggest that SOD activities in Rhodiola-seedlings may be related with the important defence-system against injurious environments.

Antifungal activities of juglone and naphthazarine derivatives

  • Chae, Mi-Jin;Choi, Ik-Hwa;Han, Ja-Young;Jong, Ok-Jai;Ryu, Chung-Kyu
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.185.3-185.3
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    • 2003
  • Juglone and naphthazarine derivatives were newly systhesized for the evaluation of antifungal activities. These derivatives were prepared by methylation of juglone and 2, 3-dichloro-5, 8-dihydroxy-l, 4-naphthoquinone, and by regioselective nucleophilic subsitution with arylthiols. All compounds were tested in vitro for their growth inhibitory activities against pathogenic fungi by the standard method. The MIC values were determined by comparison to flucytosine as a standard agent. (omitted)

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Quantitative structure-activity relationships for the growth inhibition activity of the herbicidal 3-phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole derivatives (제초성 3-Phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole 유도체들의 정량적인 구조와 생장 저해 활성과의 관계)

  • Sung, Nack-Do;Lee, Sang-Ho;Kim, Hyoung-Rae;Song, Jong-Hwan
    • The Korean Journal of Pesticide Science
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    • v.6 no.4
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    • pp.279-286
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    • 2002
  • To improve the growth inhibition activities and selectivities for quinclorac family, novel 3-substituted phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole derivatives as the substrate were synthesized and their the activities ($pI_{50}$) against shoot and root of rice plant (Oryza sativa L.) and barn-yard grass (Echinochloa crus-galli) were measured. And the quantitative structure-activity relationships (QSARs) between physicochemical parameters of the substitutents (R) on phenyl group and the activities ($pI_{50}$) were analyzed quantitatively. According to the SAR analyses, the substrates of planar conformation showed higher herbicidal activities against barnyard grass than rice plant. The activities against rice plant depend on the electronic effect (shoots: ${\sigma}_{opt.}=0.49$ & root: $R_{opt.}=-0.15$) of substituents, whereas the activities against shoots and roots of barnyard grass depend on hydrophobicity (${\pi}_{opt.}=0.37{\sim}2.40$). There were conditions of selective growth inhibition activity against barnyard grass when such a ortho-substituted electron donating substituents showing the hydrophobicity value, ${\pi}=2.40$ were introduced on the phenyl ring. The 2-tolyl substituent predicted from SAR equations was expected to have better growth inhibition activity and selectivity (${\Delta}pI_{50}=1.26$) for barnyard grass.