Factors affecting root rot of ginseng and development of the disease forecasting model

학위논문(박사)--서울大學校 大學院 :農生物學科 植物病理學專攻,1995.Docto

Rate optimization and routing for energy efficiency with retransmissions in wireless Ad-Hoc networks

학위논문(석사) --서울대학교 대학원 :전기. 컴퓨터공학부,2007.Maste

Novel emulsifier from marine microorganism

1

Hahella chejuensis Pigments Killing Red-tide Microalgae

Algicidal effect of red pigment of a marine bacterium Hahella chejuensis strain 96CJ10356 were tested with Cochlodinium polykrikoides, Gyrodinium impudicum, Heterosigma akashio, Procentrium micans and Alexandium catenella. Among the tested species three species of red-tide microalgae, Cochlodinium polykrikoides, Gyrodinium impudicum and Heterosigma akashio showed strong cell lysis in the presence of red pigment, which had maximum absorptions at 486 and 539 nm. In f/2 medium containing 1 mg/l ethanol-soluble crude red pigment, more than 99.1% of C. polykrikoides cells were lysed within 1 h, At the same conditions, cell lysis density of G. impudicum was 59.7, and H. akashiond 72.9%, respectively. After exposure to this pigment, the algal cells lose their motility, became round, expanded and finally burst.2

Algicidal effect of Red Pigment from the Marine Bacterium Hahella chejuensis strain 96CJ10356 on Red-tide Microalgae

The algicidal effects of red pigment from the marine bacterium Hahella chejuensis strain 96CJ10356 on two species of red-tide microalgae (Cochlodinium polykrikoides and Gyrodinium impudicum) were examined. The isopropanol-soluble crude red pigments with maximum absorptions at 496, and 533.5 nm, were produced. Swimming cell density of C. polykrikoides and G. impudicum decreased to less than 8% of the initial density within 1 h in f/2 medium containing 10 mg/l crude red pigment. After losing their motility, almost all of the cells became round and then expanded and burst. Once cells had become round, none of them recovered to normal vegetative cells within 24 h even if they were transplanted to f/2 medium.1

A novel sulfated polysaccharide derived from the marine microalgae Gyrodinium impudicum strain KG03 with immunostimulating activity in vitro

1

Novel Exopolysaccharide from Marine Biofilm-Forming Microorganisms

We performed 1) isolation of bacteria from the various slides that had been exposed to natural seawater and the natural biofilms, 2) identification of bacterial strains, 3) estimation of exopolysaccharide-producing ability, 4) characterization of the exopolysaccharide produced by selected strains, and 5) presentation of usage from isolated exopolysaccharide.2

Exopolysaccharide from Colorless Mutant of Hahella chejuensis strain 96CJ10356

Red pigment forming Hahella chejuensis 96CJ10356 producde novel viscous exopolysaccharide(EPS), named as EPS-R. In order to prepare colorless EPS, mutants of H. chejuensis 96CJ10356 were developed using by EMS (ethylmetane sulfonate) mutagenesis. Strain m10356, one of non-pigment forming mutants, produced white colored EPS, p-m10356 with higher productivity. The characteristics of p-m10356 such as average molecular masses, sugar compositions, element composition, thermal properties were analyzed. After the effects of salt, pH, temperature, inorganic compounds, and C, N-source were tested, M-m10356 medium was proposed for optimal EPS production. Rheological properties of p-M10356 at various temperatures, concentrations, salts, pH and mixed other polysaccharide were monitored using oscillatory measurement and steady-shear viscosity measurement.2