• Journal of Microbiology and Biotechnology
• /
• v.20 no.3
• /
• pp.494-500
• /
• 2010

Bacterial blight, an important and potentially destructive bacterial disease in rice, is caused by Xanthomonas oryzae. Recently, this organism has developed resistance to available antibiotics, prompting scientists to find a suitable alternative. This study focused on secondary metabolites of Phomopsis longicolla to target X. oryzae. Five bioactive compounds were isolated by activity-guided fractionation from ethyl acetate extracts of mycelia and were identified by LC/MS and NMR spectroscopy as dicerandrol A, dicerandrol B, dicerandrol C, deacetylphomoxanthone B, and fusaristatin A. This is the first time fusaristatin A has been isolated from Phomopsis sp. Deacetylphomoxanthone B showed a higher antibacterial effect against X. oryzae KACC 10331 than the positive control (2,4-diacetyphloroglucinol). Dicerandrol A also showed high antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and yeast (Candida albicans). In addition, high production yields of these compounds were obtained at the stationary and death phases.

• Proceedings of the Korean Society of Organic Agriculture Conference
• /
• 2009.12a
• /
• pp.319-319
• /
• 2009

관행재배 농산물에 대한 유기재배 농산물의 우수성이 구전되고 있으나 객관적인 과학적 데이터가 부족한 실정이다. 그래서 본 연구에서는 한국인이 주식으로 하고 있는 쌀(동진 1호)을 대상으로 생산이력이 분명한 유기 및 관행재배 시료를 이용하여 독자적으로 확립한 분석법을 이용해 유기 및 관행재배 쌀에 함유된 생리활성성분의 함량 비교를 행하였다. 생리활성성분 분석은 $\gamma$-oryzanol, $\beta$-sitosterol 및 tocopherol류를 대상으로 행하였다. 쌀에 함유된 주요 4종의 $\gamma$-oryzanol류의 동정을 위해 그 4종 화합물들을 ESI-MS 및 NMR 분석을 행한 결과, ODS 컬럼 상에서 cycloartenyl ferulate, 24-methylene cycloartenyl ferulate, campesteryl ferulate 및 $\beta$-sitosteryl ferulate 순으로 용출됨을 확인하였다. 동정된 각 성분들을 HPLC로 분석한 결과, cycloartenyl ferulate와 $\beta$-sitosteryl ferulate의 함량은관행보다 유기재배 쌀에서 유의(p<0.05)하게 높은 값을 보였다. 또한 $\gamma$-oryzanol 중 24-methylene cycloartenyl ferulate와 campesteryl ferulate의 함량은 유의차는 인정되지 않았으나 관행보다 유기재배 쌀에서 더 높은 경향을 보였다. 그리고 $\beta$-sitosterol 함량에 있어서는 유의차가 인정되지 않았으나 관행보다 유기재배 쌀에서 더 높은 경향을 나타냈다. 관행재배와 유기재배 쌀의 tocopherol류의 함량을 분석한 결과, $\alpha$-tocopherol의 함량에 있어서는 관행과 유기재배 쌀 간의 유의차가 관찰되지 않았고, $\beta$- and/or $\gamma$-tocopherols의 함량에 있어서는 유기재배 쌀에서 더 높은 경향이 관찰되었다. 이처럼 쌀에 함유된 생리활성 성분과 그로 인해 발휘되는 기능성 측면에 있어서 유기농산물의 우수성은 유기농산물 재배 농가의 수익 창출에 도움이 되는 홍보자료 제공 및 식품 기능학적 측면에 있어 중요한 기초자료로 활용될 수 있으리라 기대된다. 그러나 본 결과는 본 실험에서 대상으로 한 시료에 한정될 수 있으며, 유기재배 방법과 재배환경 및 조건에 따라 다양한 결과가 얻어질 수 있음에 주의가 요구된다.

• Journal of Microbiology
• /
• v.44 no.4
• /
• pp.369-374
• /
• 2006

To investigate the mechanism of salt tolerance of gram-positive moderately halophilic bacteria, two-dimensional gel electrophoresis (2-D PAGE) was employed to achieve high resolution maps of proteins of Halobacillus dabanensis $D-8^T$. Approximately 700 spots of proteins were identified from these 2-D PAGE maps. The majority of these proteins had molecular weights between 17.5 and 66 kDa, and most of them were distributed between the isoelectric points (pI) 4.0 and 5.9. Some protein spots were distributed in the more acidic region of the 2-D gel (pI <4.0). This pattern indicated that a number of proteins in the strain $D-8^T$ are acidic. To understand the adaptation mechanisms of moderately halophilic bacteria in response to sudden environmental changes, differential protein profiles of this strain were investigated by 2-D PAGE and $Imagemaster^{TM}$ 2D Platinum software after the cells were subjected to salt shock of 1 to 25% salinity for 5 and 50 min. Analysis showed 59 proteins with an altered level of expression as the result of the exposure to salt shock. Eighteen proteins had increased expression, S proteins were induced, and the expression of 33 proteins was down-regulated. Eight of the up-regulated proteins were identified using MALDI-TOF/MS and MASCOT, and were similar to proteins involved in signal transduction, proteins participating in energy metabolism pathways and proteins involved in stress.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.2
• /
• pp.1-13
• /
• 2014

In IEEE 802.11p/1609-based vehicular networks, vehicles are allowed to exchange safety and control messages only within time periods, called control channel (CCH) interval, which are scheduled periodically. Currently, the length of the CCH interval is set to the fixed value (i.e. 50ms). However, the fixed-length intervals cannot be effective for dynamically changing traffic load. Hence, some protocols have been recently proposed to support variable-length CCH intervals in order to improve channel utilization. In existing protocols, the CCH interval is subdivided into safety and non-safety intervals, and the length of each interval is dynamically adjusted to accommodate the estimated traffic load. However, they do not consider the presence of hidden nodes. Consequently, messages transmitted in each interval are likely to overlap with simultaneous transmissions (i.e. interference) from hidden nodes. Particularly, life-critical safety messages which are exchanged within the safety interval can be unreliably delivered due to such interference, which deteriorates QoS of safety applications such as cooperative collision warning. In this paper, we therefore propose a new interference-aware Dynamic Safety Interval (DSI) protocol. DSI calculates the number of vehicles sharing the channel with the consideration of hidden nodes. The safety interval is derived based on the measured number of vehicles. From simulation study using the ns-2, we verified that DSI outperforms the existing protocols in terms of various metrics such as broadcast delivery ration, collision probability and safety message delay.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.4
• /
• pp.613-618
• /
• 2015

This paper proposed a low power CMOS Flash-SAR A/D converter which consists of a Flash A/D converter for 2 most significant bits and a SAR A/D converter with capacitor D/A converter for 8 least significant bits. Employment of a Flash A/D converter allows the proposed circuit to enhance the conversion speed. The SAR A/D converter with capacitor D/A converter provides a low power dissipation. The proposed A/D converter consumes $136{\mu}W$ with a power supply of 1V under a $0.18{\mu}m$ CMOS process and achieves 9.16 effective number of bits for sampling frequency up to 2MHz. Therefore it results in 120fJ/step of Figure of Merit (FoM).

• Bulletin of the Korean Chemical Society
• /
• v.30 no.10
• /
• pp.2227-2232
• /
• 2009

Novel polythiol materials of urethane lens series for plastic optical lens were synthesized from polyol materials via thioisouronium of thiourea with c-HCl in refluxing aqueous solution, in which polythiol material was carried out from hydrolysis of thioisouronium by ammonia water. Their structure properties were identified by EA, EI-MS, FT-IR, $^1H\;and\;^{13}C$ NMR spectroscopies and TGA. Their ophthalmic lenses as polythiourethane material were prepared by thermal curing to an injected glass mold using the evenly solutions of diisocyanates series (TDI, XDI, HDI or IPDI) with polythiols. Polythiourethane shows that the strong stretching mode for SH group of polythiol disappeared in FT-IR spectra after thermosetting polymerization. Thermal deformation starting temperature of ophthalmic lenses was determined by TMA. Ophthalmic lenses made from characteristic polythiol and diisocyanate series have transparency, colorless and good impact strength, in which thermal resistance and impact strength of ophthalmic lenses were influenced by diisocyanate series. Physical properties of ophthalmic lens have contrast thermal resistance with impact strength. The property of thermal resistance and impact strength for respective ophthalmic lenses was examined by TMA and drop ball test.

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.1
• /
• pp.27-33
• /
• 1996

The aim of this research was to investigate the chemical components of C30 compounds, especially triterpenoids in Korean native mistletoes of Korthalsella japonicus Engler parasiting to Camellia japonica L., Viscum album var. coloratum (Kom.) Ohmi, to Quercus acutissima Carruth. and Loran-thus yadoriko Sieb. to Neolitsea sericea (BI.) Koidz. For the identification of triterpenoidal components, alkaline hydrolyzates of mistletoes meals were analyzed by TLC, GC, and GC/MS. The content of oleanolic acid and ursolic acid derivatives were highest in K. japonica. In V. album, there was no big difference between leaves and twigs in content. but oleanolic acid in leaves. and olean-12-en-$3{\beta}$-ol and lup-20(29)-en-3-one in twigs were prominent. Similiar to V. album in L. yadoriki there was no difference between leaves and twigs in content, and both olean-12-en-$3{\beta}$-ol, lup-20(29)-en-3-one and urs-12-en-$3{\beta}$-ol in leaves, lup-20(29)-en-3-one in twigs were abundant. Triterpenoids as olea-12-en-$3{\beta}$-ol, lupe-20(29)-en-3-one, 3-oxo-urs-12-en-24-oic acid, and $21{\beta}$-A'-neogam-macer-22(29)-en-3-ol acetate were common in all samples tested. whereas ursolic acid only in P. japonicus and ursenol in L. yadoriki were detected. And P. japonicus had the largest number of triterpenoids and showed the highest in biological activity. So it is noted that Korean mistletoes tested in the study had three types of triterpenoid, oleanane, lupane, and ursane, irrespective of hosts, sampling positions and species.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.9
• /
• pp.921-929
• /
• 2011

Stimulation of AMP-activated protein kinase (AMPK) signaling followed by increase of glucose uptake in L6 myotubes were studied with organic solvent extract of Malva verticillata (MV) seeds. Ethanol extract of M. verticillata seeds (MVE) significantly increased the phosphorylation level of AMPK, acetyl-CoA carboxylase (ACC), and glucose uptake in L6 myotube cells. The MVE was fractionated with n-hexane (MVE-H), chloroform (MVE-C), ethylacetate (MVE-E), n-butanol (MVE-B), and water (MVE-W). MVE-H (150 ${\mu}g$/ml) showed the highest phosphorylating activity and increased glucose uptake by 2.3-fold. Oral administration of MVE-H (40 mg/kg) for 4 weeks to type 2 diabetic (db/db) mice reduced non-fasting and fasting blood glucose levels by 17.1% and 23.3%, respectively. Phosphorylation levels of AMPK and ACC in the soleus muscle and liver tissue of db/db mice were significantly increased by the administration of MVE-H. MVE-H was further fractionated using preparative HPLC to identify the AMPK-activating compounds. The NMR and GC-MS analyses revealed that ${\beta}$-sitosterol was a major effective compound in MVE-H. Phosphorylation levels of AMPK and ACC, and glucose uptake were significantly increased by the treatment of MVE-S (${\beta}$-sitosterol) isolated from M. verticillata to L6 cells, and these effects were attenuated by an AMPK inhibitor (Compound C) pretreatment. These results, taken together, demonstrate that increased glucose uptake in L6 myotubes by MVE-H treatment is mainly accomplished through the activation of AMPK. Our finding suggests that the extract isolated from M. verticillata seed would be beneficial for the treatment of metabolic disease including type 2 diabetes and hyperlipidemia.

• Journal of Korean Society of Forest Science
• /
• v.86 no.4
• /
• pp.430-434
• /
• 1997

Axillary bud explants from 3-year-old seedlings of Forsythia saxatilis N., rare and endangered species in Korea, were cultured on Murashige and Skoog's medium. The effect of various cytokinins(BAP, kinetin, and zeatin) at the different concentration(0.2, 0.5 and 1.0mg/L) was tested. Although an apparent shoot proliferation was not observed, zeatin showed slight promotional effect on normal shoot and leaf development. Both shoots and adventive roots could be induced simultaneously when the explants were cultured on the medium with kinetin, but adventive rooting was gradually reduced according as BAP and zeatin concentrations increased. Axillary shoot growth was promoted by the etiolation treatment. Shoot proliferation has been maintained more than three years with consecutive subculture. Rooted plantlets were successfully acclimatized in the artificial soil mixture and showed normal growth after transplantation into field.

• Convergence Security Journal
• /
• v.8 no.2
• /
• pp.57-62
• /
• 2008

In this paper, we suggest new fast recovery mechanism in RPR network, in case of node addition or removing by exterior attack. A RPR network recovery time is consist of two. Failure detecting time and reporting time are that. In this paper we propose fast recovery mechanism that can reduce each time. In a Legacy recovery mechanism, To report node's state, rpr node transmit protection messages. But interval of this protection messages increase exponentially. Thus A transmission failure of protection message cause delay of reporting of network state. Therefore we propose new node state reporting mechanism that put a node state in type b fairness message. And We also suggest fast failure detecting mechanism.