• The Journal of Natural Sciences
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• v.7
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• pp.91-101
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• 1995

To establish the simple and practical test method of estimating resistance of rice varieties against rice leafblight, trials were made to correlate among the four test methods such as true resistance test,secondaryinfection test, secondary epidemic test and field test. The results obtained through the experiment on 25 ricevarieties and 3 pathogenic isolates designated to HB9O11, HB9022 and HB9033 can be summarized asfollows. 1 .Based on the results of true resistance test, 25 rice varieties can be classified into four groups:1 )Samgang variety group ;resistant to HB9011, 13 varieties, 2)Pungsan variety group ; resistant to HB9011 and HB9022, 5 varieties, 3)Samgang variety group ; resistant to all three isolates, 2 varieties, 4)Unbongvariety group: sensitive to all three isolates, 12 varieties. 2. The responses of rice varieties to isolates showed some discrepancies among on the test methods. These examples were found in 3 varieties including Yeongdeog varieties to HB9011, 3 varieties including Taebaeg variety to HB9022 and Taebaek vaieties to HB9033. 3. Correlation coefficiences between the secondary infection test and the secondary epidemic test for HB9011, HB9022 and HB9033 were 0.972, 0.894 and 0.919, respectively. It suggests that the two methods are not significantly different so that one of the two methods are not significantly different so that one of the two methods can be omitted from resistant test without affecting the result. 4. Between the true resistance test and the field test at the disease common area, there were no significant correlations. Unbong, Chucheong and Yeongdeog varieties are appeared as resistant varieties in the true resistant test, but their responses in the field test were different and appeared as sensitive varieties. 5. The disease index was used to express theresults from four test methods. The disease index was calculated as the sum of each numerical values of theresults from the four test methods by giving the same weights(0 to 25)to each test method. If the disease index for certain variety is less than 15, then the variety is considered to be resistant. 4 varieties such as Seohae, Hwajin, Yeongdeog and Pungsan varieties-disease indices were less than 15 were selected as field resistance varieties.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.15-21
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• 2005

This Study was conducted to investigate the effects of microbial phytase in low phosphirus and calcium level diet on the performance and nutrient digestibility in laying hens. One hundred ninety two, 50 wks old, ISA brown commerical layers were used for 12 weeks feeding trial after 7-d adjustment period. Four dietary treatments included CON(control; Co.), P2 ($0.06\%$ Natuphos, BASF) and P3 ($0.06\%$ PHOSMAX, GENOFOCUS). Ca and available P concentrations of P1, P2 and P3 were 90 and $50\%$ of NRC recommecdations to accentuate difference in response to phytase availability. In whole period, egg production was not affected by treatments. At 12 weeks, egg weight was significantly increased in adding phytase treatments (P<0.05). Egg shell thickness was increased in P1, P2 and P3 treatments compared with control (P<0.05) at 9 weeks. Ca concentration of serum tended to decrease in P1 treatment without significant difference (P>0.05). Ca and P concentrations of tibia were higher in layers fed dietary phyrase than those fed control diet without significant difference (P>0.05). Digestibilities of DM, N and ash were improved in P1 treatment compared with P2 and P3 treatments (P<0.05). Ca and P digestibilities were the highest in P2 treatment (P>0.05), but was not significant difference between control and P1 treatments.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.408-413
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• 2008

Rice blast resistance is considered one of the most important traits in rice breeding and the disease, caused by Magnaporthe grisea Barr, has brought significant crop losses annually. Moreover, breakdown of resistance normally occurs in two to five years after cultivar release, thus a more durable resistance is needed for better control of this disease. We developed a new variety, Keumo3, which showed strong resistance to leaf blast. It was tested in 2003 to 2007 at fourteen blast nursery sites covering entire rice-growing regions of South Korea. It showed resistance reactions in 12 regions and moderate in 2 regions without showing susceptible reactions. Durability test by sequential planting method indicated that this variety had better resistance. Results showed that Keumo3 was incompatible against 19 blast isolates with the exception of KI101 by artificial inoculation. To understand the genetic control of blast resistance in rice cultivar Keumo3 and facilitate its utilization, recombinant inbred lines (RIL) consisting of 290 F5 lines derived from Akidagomachi/Keumo3 were analyzed and genotyped with Pizt InDel marker zt56591. The recombination value between the marker allele of zt56591 and bioassay data of blast nursery test was 1.1%. These results indicated that MAS can be applied in selecting breeding populations for blast resistance using zt56591 as DNA marker.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.384-397
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• 2018

The aim of this study is to screen the strains of Bacillus spp. possessing safety, probiotic activity, and so on, which can be utilized as probiotic resource for using the feed and supplement food of companion animal. About 300 isolates were isolated from traditional Korean sauces, four isolates that did not have or produce the six kinds of B. cereus type vomiting and diarrhea toxin genes, ${\beta}$-hemolytic, and three kinds of carcinogenic enzymes were selected. Antibiotic gene retention, cell surface hydrophobicity, antibiotic sensitivity, and glucose utilization were analyzed for four isolates, and finally SRCM 100731 was selected. SRCM 100731 was named as Bacillus amyloliquefaciens SRCM 100731 16S rRNA sequencing analysis, and carried out optimization of cell growth for industrial applications such as pet food and feed. The effects of 14 different components on cell growth were investigated and three significant positive factors, molasses, sodium chloride, and potassium chloride were selected as the main factors based on a Plackett-Burman design. In order to find out optimal concentration on each constituent, we carried out central composite design. The predicted optimized concentrations were 7% molasses, 1.1% sodium chloride, 0.5% potassium chloride. Finally, an overall about 7-fold increase in dry cell weight yield ($12.6625{\pm}0.0658g/L$) was achieved using the optimized medium compared with the non-optimized medium ($1.8273{\pm}0.0214g/L$). This research is expected to be highly utilized in the growing pet industry by establishing optimal cultivation conditions for industrial application as well as screening Bacillus amyloliquefaciens SRCM 100731 as probiotic resource for companion animal.

• Journal of the Korean Society of Food Culture
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• v.7 no.3
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• pp.259-270
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• 1992

The changes in life style today appear many ways. Many housewives turn away from home preparation of the time consuming traditional foods, such as 'Andong sikhe'. The importance, however, of succeeding the traditional cuisines is getting appreciated widely nowadays. This study aimed to investigate the preparation of Andong sikhe by use of pure culture inoculation and the improvement of storage stability by the addition of stabilizers to the product. Lactobacillus delbreuckii was selected for the pure culture inoculation in the fermentation. The changes in chemical composition such as total acidity, sugar content, amino acid and various forms of nitrogen during fermentation were determined. The changes in pH of the product, the enzyme activities and the population of lactic acid bacteria were also followed in the process of fermentation. The Lactobacillus dominated in the beginning of the fermentation but the Streptococcus out numbered the former as the fermentation proceeded. The crude protein content increased up to the 4th day of fermentation but slowly decreased there after. The pH of the product rapidly decreased to 4.2 by the 2nd day of fermentation. The total acidity reached to the 0.38% by the 2nd day of fermentation and kept on increasing slowly during the fermentation. The free sugar consisted of 6 kinds including maltose and one unknown sugar. The amino form nitrogen increased up to 38.5mg% at the 2nd day of fermentation and the product tasted best at this time. The ammonia form nitrogen, water soluble and salt soluble protein decreased during fermentation. Proline and aspartic acid were the two major free amino acids. The free methionine increased while the free lysine decreased in the process of fermentation. The major amino acids of water soluble and salt soluble protein were glutamic acid and aspartic acid. The arginine content of salt soluble protein increased as the fermentation proceeded. Linoleic, palmitic and oleic acid were the three major fatty acids and occupy 90% or more of the total fatty acids. The activities of acid protease and liquefying amylase reached to the maximum at the 4th day of fermentation while those of saccharogenic amylase and lipase reached to the peak at the 2nd day of fermentation.

• Journal of Mushroom
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• v.14 no.2
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• pp.59-63
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• 2016

A new commercial strain of oyster mushroom (was developed by hyphal anastomosis, and was improved byhybridization between a monokaryotic strain derived from Pleurotus ostreatus ASI 0635 (Gonji 7ho) and a dikaryotic strain derived from P. ostreatus ASI 0666 (Mongdol). The optimum temperatures for mycelial growth and fruiting body development were $25{\sim}30^{\circ}C$ and $12{\sim}18^{\circ}C$, respectively. When PDA (potato dextrose agar medium) and MCM (mushroom complete medium) were compared, mycelial growth was faster in MCM. Similar results were observed with the control strain P. ostreatus ASI 2504 (Suhan 1ho). Analysis of the genetic characteristics of the new cultivar ('Gosol') showed a different DNA profile from that of the control ASI 2504 strain, when RAPD (raurpDNA) primers URP1, 2, 3, and 7 were used. Fruiting body production per bottle was approximately116 g based on a production performance test. In addition, yields from a farm field trial were stably achieved in an inadequate production enviro. The color of the pileus was blackish gray, and the stipe was long and thick. Therefore, we expect that this new strain will satisfy consumer demand for high quality mushrooms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1576-1582
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• 2008

This study was conducted to investigate the effect of administration of calcium supplementary food containing fermented product of Bacillus subtilis SE4 highly producing poly-$\gamma$-glutamic acid on the growthparameters of adolescent male rats. Four-week old male Sprague-Dawley (SD) rats were fed for 4 weeks and assigned to the following 4 groups: two groups administered orally with new calcium supplementary food (such as 150 mg/kg and 300 mg/kg) containing fermented product of B. subtilis SE4, one group administered with conventional calcium supplementary food product (150 mg/kg) and one saline group as control. Daily weight gain and daily food intake in the two new food product groups were higher than those of conventional food product group and control group. Especially, the content of serum IGF-I in the two new food product groups were significantly higher than those in conventional food product group and in control group (p<0.05). In addition, length and weight of longitudinal bone in the two new food product groups were longer and heavier than those of conventional food product group and control group. Therefore, the addition of fermented food product of B. subtilis SE4 into the conventional calcium supplementary food increased all the parameters examined for the growth of the adolescent male rats.

• Journal of Mushroom
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• v.10 no.3
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• pp.120-128
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• 2012

Recently sawdust cultivation of Shiitake mushroom (Lentinula edodes) is increasing. It is important to make mycelia to be brown on the substrate surface. This browned surface in sawdust cultivation plays an important role like as artificial bark of the oak log, which protects the other pests and suppresses water evaporation in the substrate. In order to isolate genes which related to brown color formation, differential display method was used. Two cDNA fragments obtained by DD-PCR were 1.2 and 1.6kb and these were expressed in white colored mycelia from L. edodes, but not brown colored mycelia. Partial sequencing of these cDNA fragments showed that the 1.6kb cDNA had 100% identity with the microsatellites gene from Dugenia polichroa. However, the other 1.2kb cDNA fragment had poly T tail on 3' region of partial open reading frame on 5' region. The new primer designed based on the sequence of 1.2kb cDNA was constructed. RT-PCR analysis using the newly designed 0.12kb cDNA specific primer showed that the gene was only expressed in white color mycelia, but not in brown color mycelia. Sequence analysis of 5' region of this 1.2kb cDNA revealed that this gene contained partial open reading frame consisted of 110 amino acid. Homology search using DNASIS database showed that this gene had high sequence homology of 66.7% in DNA level and 69.2 % in amino acid level with dTDP-glucose 4,6-dehydratases gene from Arabidopsis thaliata. The dTDP-glucose 4,6-dehydratases gene was known to be function to have tolerance with oxidation stress. These results strongly suggest that this gene isolated from white mycelia of L. edodes might have a function of repressor against mycelia browning. Therefore I designated this gene as BCR (Brown Color Repressor) gene.

• Journal of Mushroom
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• v.10 no.3
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• pp.109-114
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• 2012

To develop new variety of oyster mushroom, 63 intra-specific hybrids between the strain Suhan and #Nongi201 were developed using hyphal anastomosis technique in 2004. The Po2008-275 hybrid between the dikaryon strain 04-154(Suhan x #Nongi201) and the monokaryon strain derived from ASI2487 were developed using hyphal anastomosis in 2008. The Po2008-275 was shown the best cultural characteristics, selected to be a new variety and named as 'Guseol'. The new commercial strain, 'Guseol' had dark grey pilei and grows well under spring and autumn conditions in Korea. The fruiting bodies of 'Guseol' were of an excellent quality in that not only the stipe was thick and long but also the pileus was small and hard. The optimum temperatures for mycelial growth and fruiting body development were $25{\sim}30^{\circ}C$ and $10{\sim}16^{\circ}C$, respectively. Time period required for the initiation of the first fruiting body was about 3 to 5 days depending on the temperatures. The shape of fruiting body was thin funnel shape. Fruiting body production per box($43{\times}43{\times}12cm$) was about $1545{\pm}400.9g$ which was almost 137% quantity compared to that of parental strain 04-154. Relatively low temperature incubation ($11^{\circ}C$) resulted in the development of better quality of 'Guseol' mushrooms. When two different media including potato dextrose medium and mushroom complete medium were compared, the mycelial growth of this mushroom were much faster in mushroom complete medium. Similar results were observed with other variety '#Chunchu2'. Analysis of the genetic characteristics of the new commercial strain 'Guseol' showed a major DNA profile as that of the parental 04-154 when primer URP 1, primer URP 2 and primer URP 5 were used, but different to '#Chunchu2' that was used as a control. This new variety of the dark grey oyster mushroom had smart and high quality image that corresponds well to "health food". We therefore expect that this new strain will satisfy the consumers demand for variety and excellent mushrooms.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.437-444
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• 2009

${\gamma}-Aminobutyric$ acid (GABA) producing lactic acid bacteria, Lactobacillus acidophilus RMK567 was cultivated in 50 L of sterilized MRS broth using a fermenter at $40^{\circ}C$ for 24 h. The cell number was increased to $10.04{\pm}0.13$ Log CFU/mL with a growth rate constant (k) of 0.454 generation/h and a generation time (g) of 2.303 h after a lapse of a lag phase (L) of 5.16 h. A total of 487 g of cell paste with 40.5% moisture was harvested with viable cell number of 12.48 Log CFU/g cell paste. The cell pastes after preparation with glycerol, glucose, and polydextrose as cryo-protectants were lyophilized under a vacuum of 84 m torr. A total of 408 g of freeze dried (FD) cell powders were mixed with a commercial strain of Streptococcus thermophilus to prepare of three types FD starter cultures with the viable cell numbers of 12.42 (FDA-GY), 12.60 (FDBGG) and 12.91 (FDC-GP) Log CFU/g. During preservation the FD cultures at -$18^{\circ}C$, the cell viability of the FD starter cultures were rapidly dropped to below 3.24% of the day of storage. No significant difference was found in the cell viabilities among three types of FD starters cultures, but significant difference (p<0.01) was found in storage periods. Yoghurts fermented through FD starter culture of L. acidophilus RMK567 were determined to contain $155.16{\pm}8.53$ ppm, $243.82{\pm}4.27$ ppm, and $198.64{\pm}23.46$ ppm of GABA, respectively. This study shows that GABA production activity of L. acidophilus RMK567 is not affected during the freeze drying process and would be available for commercial production of yoghurt containing high GABA content.