• Korean journal of applied entomology
• /
• v.17 no.1 s.34
• /
• pp.23-28
• /
• 1978

The study has been carried to confirm the pathotypes of Kresek inducing isolates of X. oryzae, and its reaction to the test plants when they were inoculated by the use of various methods. Induction of Kresek symptom by 23 isolates which randomly samplified from 123 Kresek areas through the country also were examined. The specificity of Pathotypes I, II, V in causing Kresek and the potenciality of infected rice straw is a first inoculum for Kresek epidemics in nature were tested. Fifteen out of 23 isolates from kresek area belonged to pathotype group I, while the rest of 8 isolates 5 howed group II reaction, and the most of isolates were originated from infected rice plant of Milyang #23. All of five pathotype groups were abled to produce 'Kresek' symptom although they showed some differences in each group of pathotype. The varieties Milyang #21, 22 and 23 were attacked by all isolates of group I, II and V while the Gogyoku group varieties including Yushin produced kresek symptom only by pathotype group II. Infected and dried straw maintained the pathogens during the winter period, and these straw acted as a first inoculum of Kresek disease when the straw were cutted and used as a manure just before transplanting of rice seedling.

• Applied Biological Chemistry
• /
• v.22 no.3
• /
• pp.166-172
• /
• 1979

A series of experiments was planned for practical application of rhizobia in grass lands in Korea. This is the report for the studies mainly on the isolation and characterization of alfalfa nodule bacteria, and on the assessment of their nodulation abilities and nitrogen fixation capacities. 1. Total number of 47 strains was isolated from nodules which were taken from alfalfa grown in Daekwanyong, Cheju and other places. 2. Morphological and cultural characteristics of the strains were studied, and attempts. were also made to investigate their antigenic properties and to demonstrate lysogenic strains. The results were; i) the isolates varied in their cultural characteristics on yeast mannitol broth and agar, and in degree of congo red absorption; ii) similarities in their antigenic prorerties were found between the strains: SU 47/M-11, M-13/M-15, and M-3/M-5; iii) no lysogeny was found in the strains. 3. Plant infection test by test tube method in light room were carried out to elucidate the ability of the strains to nodulate Luna alfalfa and of the capacity of such nodules to fix atmospheric nitrogen. The isolates were grouped info non-invasive, ineffective, or effective to the legumes. Those strains which produced effective nodules, supporting similar/higher level of growth as nitrate control were: M-8, 9, 14, 20, 21, 25 and 34.

• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.1
• /
• pp.67-72
• /
• 1990

A number of nitrogen-fixing microorganisms were isolated from roots of non-legumious crops and evaluated for their nitrogen-fixing ability on their host crops. The results are summarized as follows: 1. Among nitrogen-fixing isolates obtained from 9 different crops, several isolates showed relatively higher level of acetylene reduction activity on Spinach, Chinese cabbage, Cucumber, mustard and Egg plant. 2. When the isolates were inoculated into 4 host crops, a number of isolates were found to grow well on Spinach, Chinese cabbage and Cucumber, but particularly well on the former. 3. Results of this study suggest that nitrogen-fixing a symbiotic microorganisms are also present and able to grow well on roots of non-legumious crops, and stimulate plant growth by promoting growth and differentiation of roots.

• Korean Journal of Environmental Agriculture
• /
• v.13 no.3
• /
• pp.288-300
• /
• 1994

Fusarium oxysporum was isolated most frequently, followed by F. moniliforme, and F. solani from infected asparagus plants grown in the field. In pathogenicity tests both with seedlings and plantlets, F. moniliforme showed higher virulence than Fusarium oxysporum did in general. Fusarium moniliforme showed more consistent virulence on both seedlings and plantlets than F. oxysporum did. Fusarium oxysporum showed higher virulence on plantlets than on seedlings. Fusarium solani showed very weak or no sign of virulence on seedlings and plantlets, respectively, in both tests. In protection tests with plantlets, most protection of asparagus against virulent fusarial infections occurred when challenge isolates were inoculated five or seven days after inoculation of protective fusarial species. Avirulent F. oxysporum was a more effective protective agent against infection of F. moniliforme than it was against F. oxysporum. Fusarium solani was more effective against infection of F. oxysporum than it was against F. moniliforme.

• KSBB Journal
• /
• v.24 no.5
• /
• pp.453-457
• /
• 2009

Contamination of marine environment with hazardous and toxic chemicals is more common these days. Bioremediation is the application of microorganism or microbial processes to degrade environmental contaminant. Because of low water solubility and volatility of diesel, bioremediation is more efficient than physical and chemical methods. The objective of this study is biodegradation of diesel in sea water by using Rhodococcus fascians which is isolated petroleum-contaminated soil. R. fascians was cultured on sea water containing diesel to determine the diesel degradability. Changes in biodegradability of diesel with various inoculum sizes, diesel concentrations, initial pH, and culture temperature were analyzed by TPH analysis using gas chromatography. The inoculum size 2% was effective for biodegrdation of diesel in sea water by R. fascians. When diesel concentration was 5%, the growth of cell was inhibited by the toxicity of diesel. The optimal temperature and initial pH for degradation of diesel in sea water were $27^{\circ}C$ and pH 8.

• Journal of Conservation Science
• /
• v.10 no.1 s.13
• /
• pp.21-30
• /
• 2001

The antibacterial and insecticidal properties of ethanol extracts and volatile components extracted from Eugenia caryophyllata, Boswellia carterii, Agastache rugosa, Aristolochia contorta, and Aquilaria agallocha were evaluated. The ethanol extract and volatile component of E. caryophyllata showed strong antimicrobial effect against all strains (Mucor hiemalis, Aspergillus niger, Penicillium funiculosum, Trichoderma viride) and the volatile component of B. carterii showed antimicrobial effect against all strains except T. viride. The ethanol extract of E. caryophyllata and A. contorta showed $100\%\;and\;32\%$ mortality against Reticulitemes spertus kyushuensis Morimoto for 48 hours and 72 hours, respectively. In the case of volatile component, E. aryophyllata showed $100\%\;and\;20\%$ mortality against R. spertus and Lyctus linearis GOZE, respectively. The main constitute, eugenol $(92\%)$ among nine components from volatile component of E. aryophyllata were identified as antibacterial active substance.

• Korean Journal of Food Science and Technology
• /
• v.30 no.3
• /
• pp.487-493
• /
• 1998

This study was attempted to investigate the changes of chemical components by different yeast strains during alcohol fermentation at $12^{\circ}C$. Saccharomyces cerevisiae, Saccharomyces cerevisiae+Schizosaccharomyces pombe, and Schizosaccharomyces pombe were inoculated in the Seibel grape must, respectively. Sch. pombe began to metabolize malic acid after 4 days fermentation actively and utilized approximately 54% of initial malic acid. Ethanol contents of S. cerevisiae, S. cerevisiae+Sch.. pombe and Sch. pombe were 11.5%, 11.2%, and 10.0%, respectively. The fermentability of Sch. pombe was slower than that of S. cerevisiae. The production of sulfite showed a positive linear relationship with the yeast growth (P<0.01). Sensory scores indicated that the wine samples fermented by S. cerevisiae and Sch. pombe were not significantly different in color, odor, after taste and overall acceptability. Especially, the taste of Sch. pombe was significantly better than that of S. cerevisiae (P<0.05).

• Applied Biological Chemistry
• /
• v.39 no.3
• /
• pp.177-182
• /
• 1996

Effects of 14 carbohydrates supplied as carbon sources on cell growth and sporulation of, and the production of insecticidal crystal proteins by Bacillus thuringiensis strains were investigated in liquid cultures. Strains grew well in media containing any one of the 14 carbohydrates supplied, reaching maximum cell densities of $10^7{\sim}10^8\;cells/ml$ in 16.7 to 22 hours after inoculation depending on the strain. Spores first appeared in 16.7 to 24.7 hours after inoculation, and 80% sporulation was reached in 28 to 51.3 hours after inoculation depending on the strain. No change in pH of media was observed after cell multiplication. The production of total protein was highest when supplied with sucrose and was lowest with starch. More insecticidal crystal proteins were produced when supplied with glucose, lactose, maltose, or sucrose. The amount of insecticidal crystal proteins produced by the strains was proportional to that of the total protein. The relative amount of individual insecticidal crystal protein species produced by B.t. kurstaki and B.t. israelensis was not influenced by the carbohydrates supplied.

• Research in Plant Disease
• /
• v.21 no.2
• /
• pp.103-106
• /
• 2015

Isolates of the rice blast fungus show a range of tissue-specificities infecting leaves, nodes, neck and panicles. Although neck and panicle blast cause significantly greater yield losses than the leaf blast, virulence tests of the blast isolates have been performed only rice leaves instead of neck and panicles. In this study, we have developed a virulence test method for neck and panicle blast. We selected three representative isolates from each of leaf, neck, and panicle blast. We observed that severe disease lesions developed on the neck and the panicles when the infected rice plants were incubated in a dew chamber for 48 h instead of 24 h when tested on leaves. Unlike the leaf blast, a typical lesion on the neck and panicles appeared after 14 days post-infection as opposed to 7 days with leaf blast. This method will be applied to examine tissue-specificity of the rice blast fungus isolates.

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.3
• /
• pp.137-142
• /
• 1997

In order to elucidate the optimum medium on the growth and tropane alkaloid production of hairy root, hairy root were induced by inoculating leaf and stem of Datura stramonium var. tatula Torr. with Agrobacterium spp. Both Agrobacterium tumefaciens $\textrm{A}_{4}$ T and A, rhizogenes ATCC 15834 among tested strains were effective on hairy root formation. Among 23 clones selected in SH (Schenk and Hildebrandt, 1972) liquid medium, DTLA9 clone was shown fast growth of hairy root and DTLE6 clone was shown high level production of tropane alkaloids. When both DTLA9 and DTLE6 clones were cultured in the GD (Gresshoff and Doy, 1972) medium, alkaloid production was higher than in 8 tested media. It was elucidated that optimum medium for root proliferation and for tropane alkaloid production is SH, GD medium, respectively.