• Korean Journal of Agricultural Science
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• v.17 no.2
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• pp.82-86
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• 1990

A Corynespora species was isolated from brown target spots developed on leaves of tomato. The fungus was identified as Corynespora cassiicola and proved to be pathogenic to tomato plants. Growth of the fungus in vitro was optimum at $27^{\circ}C$, and poor at 19 and $35^{\circ}C$. Sporulation was abundant on potato dextrose malt agar and moderate on V-8 juice agar, potato dextrose agar and Czapek agar.

• Journal of the Korean Society of Visualization
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• v.6 no.2
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• pp.45-50
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• 2008

It has been found that the colony size of bacteria grown on an agar plate decreases with increasing agar gel concentration. Evidenc from recent studies suggests that the bacterial colony dynamics is closely related with the mechanical properties of the substrate. We investigate whether bacterial growth on the agar substrate is controlled mostly by the nutrients' diffusion which is hindered more in porous medium than in solution. The number of bacterial cells in single colonies is found to be inversely correlated with agar concentration. High-resolution live cell imaging at the single bacterium level confirms that the bacterial growth rate is reduced with increasing agar concentration. There is a strong correlation between the slowed diffusion and the reduced number of cells in a high concentration of agar medium.

• KSBB Journal
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• v.11 no.5
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• pp.593-599
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• 1996

The strain which produces agar degrading enzyme was isolated from chiton(Liolophura japonica). The strain was identified as Cytophaga sp. through its morphological, physiological, and biological characteristics. For the production of agar degrading enzyme, 0.3% nutrient broth, 0.2% yeast extract and 0.5% agar was used as nitrogen and carbon source, respectively. The optimal initial pH, NaCl and temperature for the agar degrading activity of Cytophaga sp. were 7.0, 2.0% and $30{\pm}2^{\circ}C$, respectively. Agar degrading activity of enzyme obtained from Cytophaga sp. was increased until the incubation of 96hrs, but after 96hrs, the activity was decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.474-479
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• 2003

The effect of season, life stages and harvesting sites on the yield and properties of agars extracted from Gracilaria verrucosa were determined. G. verrucosa were collected seasonally from November 2001 to August 2002 at Cheongsapo and Boryong, Korea. The plants were sorted Into the different life stages (tetrasporophytes and gametophytes) and dried at $60^{\circ}C.$ The yield, sulfate, protein, uronic acid and 3,6-anhydrogalactose of the agar were determined, and standard parameters of physical quality were measured. No differences were found in yield and properties of agars from the two different harvesting sites and from lift history phases. The yield of agar was maximum in summer $(17.3-20.0\%)$ and minimum in winter $(11.9-13.1\%).$ Maximum gel strength occurred in winter when the agar yield and sulfate content were low. Gel strength was negatively correlated with agar yleld. Seasonal variations in agar yield and its quality were discussed in a view to managing the exploitation of this resource.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.110-114
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• 1999

The present study was conducted to investigate the preparative methods of agarose for gel electrophoresis from agar. Naturally occuring agar consists of two main polysaccharides, the neutral polysaccharide agarose and the acid sulphated polysaccharide agaropectin. The sulphate and carboxyl functions of the agar are accumulated in the agaropectin. The hydrophilic, non-ionogenic, rigid and transparent gel matrix of the agarose was found to be suitable for gel electrophoresis gel filtration and affinity chromatography. Agar was purified by chitosan treatment, cetylpyridinium chloride (CPC) treatment, and polyethylene glycol (PEG) treatment. Yields of agarose purified from agar with chitosan, CPC and PEG were 56.7%, 55.6% and 62.3%. It was proper to treat with chitosan in preparative methods of agarose for gel electrophoresis from agar.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.82-87
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• 1993

Fourteen samples of kimchies and soy bean pastes were used to isolate strictly anaerobic bacteria on complex BL agar and on a selective BS agar for bifidus bacteria. About $10^7$ ~ $10^8$ colonies per g sample were developed on BL agar under strictly anaerobic conditions, while BS agar supported the growth of $10^3$ ~ $10^6$ colonies per gram sample at the same condition. All colonies developed on BS agar at anaerobic conditions grew in aerobic conditions and did not show fructose6-phosphate phosphoketolase activity. Type cultures of Bifidobacterium did not grow in PYG medium containig more than 3% NaCI. From these results it is conduded that salted fermented food cannot support the growth of strictly anaerobes induding Bifidobactenum.

• Journal of Life Science
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• v.13 no.3
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• pp.258-264
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• 2003

An agar-gel added soy beverage was developed. Optimum processing conditions for preparation of agar-gel were 1.5% agar with 0.1-0.2% sodium chloride and 0.1% glucomannan. And optimum manufacture conditions for soy juice were 10% solid seasoned with 3% sugar and 0.1-0.2% salt. The result of sensory evaluation revealed that overall acceptability of soy beverage with 10% solid seasoned with 3% sugar and 0.1-0.2% salt and agar-gel made with 1.5% agar, 0.2% sodium chloride and 0.1% glucomannan exceeded other groups of samples.

• Food Engineering Progress
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• v.21 no.1
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• pp.36-41
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• 2017

The release profiles of nisin from nisin-incorporating gel foods and the antimicrobial activities of the gels on the growth of Brochothrix thermosphacta in an aqueous system containing the gels have been investigated. A linear regression model was applied to determine the diffusion coefficient (D) for the diffusion of nisin in the gel. The antimicrobial activities of nisin released from 1, 2 and 3% (w/v) agar gels on the growth of B. thermosphacta in a broth medium with and without nisin were investigated. The D decreased from $1.2{\times}10^{-2}$ to $8.2{\times}10^{-3}$ and $6.4{\times}10^{-3}cm^2/s$ as the agar concentration in the gel increased from 1 to 2 and 3% (w/v), demonstrating the diffusion rate in the gels can be controlled by the agar concentration in gel. The agar gel incorporating nisin inhibited the B. thermosphacta growth in the broth medium by prolonging the lag phase. The growth inhibition was enhanced by the addition of nisin in the medium. The results of this study exhibited that the gel food is a feasible nisin delivery system with a controlled release achieved by the adjustment of agar concentration in the system, demonstrating the potential of nisin-incorporating gel for preserving particulate-containing drinks.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.35-39
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• 1995

In order to investigate the effects of gelling agent on rice anther culture, anthers of rice (Japonica cv Daecheongbyeo) were cultured on N$_{6}$ media supplemented with 0.8, 1.2 or 1.6% Junsei agar and 05, 0.4, 0.6, 0.8 or 1.0% Gelrite (Phytagel, Sigma). On Junsei agar media, the frequency of callus induction was decreased in proportion to agar concentration. The frequency of callus induction was more increased as 67.6% and 54.8% in media containing 0.4 and 0.6% Gelrite than in agar media. The frequency of plant regeneration and spontaneous doubled-diploid was directly proportional to Junsei agar and Gelrite concentration. The number of green and spontaneous doubled diploid plant was highest on 0.6% Gelrite medium. In order to optimize the concentration of growth regulators for the callus induction medium containing 0.6% Gelrite, anthers were cultured on N$_{6}$ media supplemented with 2mg/L NAA, 2 mg/L 2,4-D, 1mg/L NAA and 1mg/L 2, 4-D, or 1mg/L NAA, 1mg/L 2,4-D and 0.5mg/L kinetin. The maximum frequency of callus induction and plant regeneration was obtained from the medium supplemented with 2 mg/L NAA and 0.6% Gelrite. In conclusion the induction of embryogenic callus, the frequency of plant regeneration and in vivo chromosome doubling was more effective in Gelrite media than in Junsei agar media.dia.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.241-247
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• 2013

For in vitro minimal-growth conservation of S. sarmentosum, the in vitro shoots with 10 mm length were cultured on Murashige and Skoog's media (MS) containing different levels of agar (0.8, 1.2, 1.6, 2%), Gelrite (0.4, 0.6, 0.8, 1%), ABA (0, 5, 10, $20mg{\cdot}L^{-1}$), and sucrose (2, 3, 6, and 9%) without subculture at $4^{\circ}C$ and $25^{\circ}C$. All media were supplemented with $0.2mg{\cdot}L^{-1}$ BA, agar and Gelrite media, with 5% sucrose, sucrose media, with 1.2% agar, and ABA media, with 5% sucrose and 1.2% agar, respectively. In vitro minimal-growth conservation in room-temperature ($25^{\circ}C$) was effective in the media containing with $10mg{\cdot}L^{-1}$ ABA or 1.6% agar, and the healthy plantlets could be preserved for 10 months without subculture. After 12 months at $4^{\circ}C$, survival rate was 100% in all media. The in vitro minimal-growth conservation in low temperature ($4^{\circ}C$) was effective in the media containing with $10mg{\cdot}L^{-1}$ ABA or 6% sucrose, and the healthy plantlets could be preserved over 18 months without subculture. Especially, long-term conservation using minimal growth of S. sarmentosum was much more efficient in the medium containing high level sucrose at $4^{\circ}C$ compared to others.