• Korean journal of applied entomology
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• v.52 no.2
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• pp.115-123
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• 2013

A microbial insecticide "Bt-Plus" has been developed to enhance an insecticidal efficacy of an entomopathogenic bacterium, Bacillus thuringiensis (Bt). However, its wettable powder formulation is not preferred by farmers and industry producers due to relatively high cost. This study aimed to develop a soluble concentrate formulation of Bt-Plus. To this end, an optimal mixture ratio of two bacterial culture broths was determined to be 5:4 (v/v) of Bt and Xenorhabdus nematophila (Xn) along with 10% ethanol preservative. In addition, Bt broth was concentrated by 10 times to apply the mixture at 1,000 times fold dilution. The resulting liquid formulation was sprayed on cabbage crop field infested by late instar larvae of the diamondback moth, Plutella xylostella. The field assay showed about 77% control efficacy at 7 days after treatment, which was comparable to those of current commercial biopesticides targeting P. xylostella. For storage test in both low and room temperatures, the liquid formation showed a relatively stable control efficacy at least for a month. To develop a quality control technique to exhibit a stable control efficacy of Bt-Plus, Bt spore density ($5{\times}10^{11}$ spores/mL) and eight active component concentrations of Xn bacterial metabolites in the formulation products have been proposed in this study.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.53-53
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• 2015

Agrobacterium tumefaciens-mediated transformation(ATMT) of Flammulina velutipes was used to produce a diverse number of transformants to discover the functions of gene that is vital for its variation color, spore pattern and cellulolytic activity. Futhermore, the transformant pool will be used as a good genetic resource for studying gene functions. Agrobacterium-mediated transformation was conducted in order to generate intentional mutants of F. velutipes strain KACC42777. Then Agrobacterium tumefaciens AGL-1 harboring pBGgHg was transformed into F. velutipes. This method is use to determine the functional gene of F. velutipes. Inverse PCR was used to insert T-DNA into the tagged chromosomal DNA segments and conducting sequence analysis of the F. velutipes. But this experiment had trouble in diverse morphological mutants because of dikaryotic nature of mushroom. It needed to make monokaryotic fruiting varients which introduced genes of compatible mating types. In this study, next generation sequencing data was generated from 28 strains of Flammulina velutipes with different phenotypes using Illumina Hiseq platform. Filtered short reads were initially aligned to the reference genome (KACC42780) to construct a SNP matrix. And then we built a phylogenetic tree based on the validated SNPs. The inferred tree represented that white- and brown- fruitbody forming strains were generally separated although three brown strains, 4103, 4028, and 4195, were grouped with white ones. This topological relationship was consistently reappeared even when we used randomly selected SNPs. Group I containing 4062, 4148, and 4195 strains and group II containing 4188, 4190, and 4194 strains formed early-divergent lineages with robust nodal supports, suggesting that they are independent groups from the members in main clades. To elucidate the distinction between white-fruitbody forming strains isolated from Korea and Japan, phylogenetic analysis was performed using their SNP data with group I members as outgroup. However, no significant genetic variation was noticed in this study. A total of 28 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4210 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr01, chr04, chr07,chr11 regions were identified to be associated with white fruitbody forming. White and Brown Fruitbody strains can be used as an identification marker for F. veluipes. We can develop some molecular markers to identify colored strains and discriminate national white varieties against Japanese ones.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.409-419
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• 2015

This study was conducted to establish an efficient screening method for watermelon plants resistant to Fusarium wilt (FW), which is caused by Fusarium oxysporum f. sp. niveum (Fon). An HA isolate was prepared from a wilted watermelon plant in Haman-gun and identified as F. oxysporum f. sp. niveum based on morphological characteristics, molecular analyses of ITS (internal transcribed spacer) and TEF (translation elongation factor $1{\alpha}$) sequences, and host specificity on cucurbits including watermelon, melon, oriental melon, and cucumber. The assay for disease response of watermelon differentials indicated that the HA isolate was race 0. Among seven liquid media tested, the highest amount of Fon spores was produced from V8-juice broth, which was selected as a medium for mass production of Fon. The disease assay for 21 watermelon and 11 watermelon-rootstock cultivars demonstrated that 20 watermelon cultivars except for 'Soknoranggul' were susceptible; 'Soknoranggul' was moderately resistant. All the tested rootstock cultivars were highly resistant to the HA isolate. The evaluation of disease development depending on various conditions suggested that an efficient screening method for FW resistance in watermelon plants is to dip the roots of 10-day-old seedlings in spore suspension of $1.0{\times}10^5-1.0{\times}10^6conidia{\cdot}mL^{-1}$ for 30 min., to transplant the seedlings to plastic pots with a fertilized soil, and then to cultivate the plants at $25^{\circ}C$ for 3 weeks.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.148-156
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• 2010

S59-4 isolate was evaluated as a potential biocontrol agent using in vivo wounded garlic bulb assay. When the spore suspension ($10^5$ spores/$m\ell$) of Penicillium hirsutum was co-inoculated with cell suspension of S59-4 isolate on wounded garlics, the isolate showed high suppressive effect to disease development. The isolate was identified as Pantoea agglomerans S59-4(Pa59-4) through Biolog system. Furthermore, soaking garlic bulbs in the suspension of Pa59-4 significantly reduced garlic decay caused by P. hirsutum. The optimal concentration of Pa59-4 for controlling garlic blue mold was $10^7\sim10^8$ cfu/$m\ell$. And suppressive effect of Pa59-4 on garlic storage decay reduced as inoculation concentration of Penicillium hirsutum increased. In addition in order to investigate population dynamics of Pa59-4 on application site of garlic cloves, two antibiotic markers, pimaricin and vancomycin were selected. Bacterial density of Pa59-4 on the wounded garlic cloves increased continuously both under room temperature condition and low temperature condition until 30days after application of Pa59-4, meanwhile that of Pa59-4 on intact garlic cloves increased until 15days after application of Pa59-4 and thereafter decreased continuously. Two culture media for mass-production of Pa59-4, LB medium and TSB medium, were selected. By-product of bio-fungicide formulated by mixing white carbon and bacterial suspension of Pa59-4 suppressed by 40 to 50% garlic blue mold. Above results suggest that Pa59-4 be a promising control agent against garlic blue mold.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.883-890
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• 2015

The soilborne fungus Fusarium oxysporum f. sp. lilii (Fol) is a serious threat to all lily cultivars, especially infecting bulbs and flowers. It has become increasingly important to develop varieties resistant against the bulb rot disease. Genetic diversity of cultivars and reliable screening methods are required for this purpose. Here, an efficient in vitro screening system for evaluating resistance to Fol in 38 in vitro-grown lily plants was investigated. Various factors including culture conditions of Fol, inoculum density, appropriate plant materials, inoculation method and duration, and incubation period of plant materials after inoculation were combined to optimize the screening method. As a result, we suggest optimal conditions for an in vitro screening system for the selection of Fol-resistant lily cultivars as follows. Fol was grown on potato dextrose agar (PDA) medium for 6 days at $25^{\circ}C$ in darkness and used as working inoculation. Spore suspensions were prepared (inoculum density: $1.0{\times}10^4$ $spores{\cdot}mL^{-1}$), and then leaf segments $1.5{\times}2.0cm^2$ were inoculated by dipping for 22 hours at $25^{\circ}C$ in dark. Later, leaves were cultured on 0.6% agar plates at $25^{\circ}C$ and 50% humidity with a photoperiod of 16 hours light/8 hours dark (fluence rate of $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) to examine the progress of bulb rot. After 7 days, disease levels were classified into indices 1 (no symptom) to 6 (serious bulb rot). Soil inoculation of Fol carried out with resistant or susceptible lily cultivars that had been selected through in vitro screening confirmed the reproducibility of results. Therefore, the in vitro screening method established in this study is efficient and reliable for selection of lily cultivars resistant against bulb rot disease.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.198-202
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• 2011

Rice has been the most important staple food in everyday meals of Korean people for thousands of years. Nowadays, it is getting increasingly used as flour ingredients in a variety of processed foods, so that it is consumed in more diversified ways. As a consequence, production volume of rice flour to manufacture rice cakes, noodles, breads, or confectioneries is recently getting increased in Korea. But there are not sufficient research outcomes to guarantee Korean consumers microbiological qualities of rice flour as well as rice. As a preliminary experiment, therefore, the microbiological profiles (aerobic mesophilic bacteria (AMB), spore-forming aerobic bacteria (SAB), lactic acid bacteria (LAB), yeasts and molds (YM), and Escherichia coli and coliforms) have been monitored for nine retailed white rice samples in this study. AMB counts ranged $10^2-10^6$ CFU/g for all the nine white rice samples. All the nine rice samples have SAB counts within a narrow range $(1.0{\times}10^2-2.5{\times}10^3$ CFU/g). LAB was detected in two white rice samples ($4.0{\times}10^2$ and $3.7{\times}10^3$ CFU/g), YM was detected in one white rice sample ($2.0{\times}10^2$ CFU/g) only. E. coli was not detected from all the nine samples. Coliforms were detected in one white rice sample ($4.1{\times}10$ CFU/g) only. All the rice samples were conclusively considered to have various microorganisms, though most of them are harmless and some, such as coliforms, may be harmful.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.221-226
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• 1985

This investigation was undertaken to clarify the effects of consecutive application of insecticide (Hexachlorocyclohexane: HCH, 10 ppm each year) and fungicide (Tetrachloroisophthalonitrile: TPN, 40 ppm each year) on changes of the composition of soil bacterial flora in the experimental plots treated with each pesticide for two years. For these purposes, the isolating of bacterial cells growing on albumin agar plate was carried out with non-treated, HCH-treated and TPN-treated soil. And these isolated strains were grouping in accordance with the first diagnostic table of Cowan & Steel based on the morphological and physiological characteristics of bacterial cells. The mortality rate of bacteria was 30% in control, 44% in HCH and 51% in TPN plot respectively, in the process of obtaining pure culture. This suggests that the application of HCH or TPN enriched the fastidious bacteria in soil. The proportion of Gram-negative strains to the total isolates was 37% in control, 37% in HCH and 75% in TPN plot respectively. This means that the application of TPN enriched Gram-negative strains in soil. And the application of TPN increased the number of Gram-negative, nonspore-forming strains, and meanwhile decreased the number of spore-forming strains. In the results, the application of HCH or TPN changed considerably the composition of soil bacterial flora. And the influences of HCH and TPH on changes of the composition of soil bacterial flora were not equal each to each.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.79-88
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• 2004

Cordyceps pruinosa grows upon dead pupae of Lepidoptera and produces one or $3{\sim}4$ club-shaped stromata per host. The stromata have distinct club-shaped head and long stalk. The length of stromata varies from $1{\sim}3\;cm$. Apical head consists of densely crowded semi-immersed perithecia, which are $360{\sim}400\;{\times}\;180{\sim}200\;{\mu}m$ in size. Asci are $150\;{\mu}m$ in length and $2.8{\sim}3\;{\mu}m$ in diameter. Ascospores, which are $124{\sim}141\;{\mu}m$ in length, have thin thread-like structures in the middle with part-spores attached on both sides. Each ascospore does not separate into part-spores after dispersal, but each part-spore germinates and together develops a colony. The imperfect form produces phialides of $15{\sim}24\;{\times}\;2{\sim}3\;{\mu}m$ size, with spherical or spindle shaped conidia of $4{\sim}6\;{\times}\;1.8{\sim}2.4\;{\mu}m$ size, The anamorph was identified as Mariannaea elegans Samson. YMA and SDAY agar media with pH 7 was produced abundant mycelial growth with high density. Best mycelial growth was observed when dextrin was used as a carbon source. Lactose, saccharose and sucrose also produced high mycelial growth. Peptone, yeast extract and tryptone produced abundant mycelial growth, when used as nitrogen sources. Highest mycelial growth and density was observed when C/N ratio was 1 : 1 at the concentration of 12.5 g/l each. $KH_2PO_4$ was the best mineral source for mycelial growth. Highest mycelial dry wt. was produced in YM and SDAY broths. Optimum inoculum for 100 ml of liquid broth was 6 mycelial discs. Similarly, optimum liquid culture period was 7 days.

• Journal of Nutrition and Health
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• v.18 no.4
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• pp.259-271
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• 1985

The purpose of this study was to develop supplementary foods for infants and young children in order to improve their nutritional status. Three formulas composed of rice, soybeans, fish, dry skim milk and sesame in varying proportions were studied. The three formulas, $RS_{1}S_{2}$, $RFS_{1}S_{2}$, and $RMS_{1}S_{2}$, were consisted of Rice(R), Soybean$(S_{1})$, Sesame$(S_{2})$ (60 : 35 : 5) , Rice, Fish(F), Soybean, Sesame (60 : 10 : 25 : 5) , and Rice, Dry Skin Milk (M), Soybean, Sesame (60 : 10 : 25 : 5), respectively. A proximate analysis and amino acid determination were made on the developed formulas. In the animal assay, growth rate, PER and FER were evaluated and biochemical analyses were also carried out. A storage test and the cost evaluation were also conducted. The summarized results are as follows : 1) The proximate composition of the three formulas were 7.3-7.4% of moisture, 15.9-21.5% of crude protein, 7.8-9.6% of crude fat and 2.5-2.8% ash. 2) The result of amino acid analysis showed that the 1st limiting amino acids of $RS_{1}S_{2}$ and $RFS_{1}S_{2}$ were lysine (amino acid score, 76.6) and threonine (amino acid score, 93.3), and that of $RMS_{1}S_{2}$ and the commercially prepared formula were sulfur containing amino acids (amino acid score, 82.0 and 54.4). When the contents of the amino acids of the three formulas were compared with mother's milk and cow's milk, the balance of the amino acid of each formula was superior to mother's milk but inferior to cow's milk. 3) In the animal assay, the growth rate of all groups increased gradually during the experimental period. 4) The C- PER, which was corrected on the basis of the casein PER of 2.5 was 2.99, 3.38 and 3.10 in the $RS_{1}S_{2}$, $RFS_{1}S_{2}$ and $RMS_{1}S_{2}$ respectively. The C- PER of $RFS_{1}S_{2}$ and $RMS_{1}S_{2}$ were Significantly (P<.05) higher than that of the casein. 5) The FER of the casein, $RS_{1}S_{2}$, $RFS_{1}S_{2}$, and $RMS_{1}S_{2}$ were 0.37, 0.39, 0.43 and 0.39, respectively. The FER of $RFS_{1}S_{2}$ and $RMS_{1}S_{2}$ were also significantly (P<.05) higher than that of the casein. 6) The concentrations of hematocrit, hemoglobin, total protein and albumin in the serum of the rats of all groups were not significantly different among groups. 7) The storage stability test showed that the total plate count (TPC), the coliforms count and the bacterial spore count in the ingredients were quiet low. However, after 30 and 60 days storage, the count in $RFS_{1}S_{2}$ increased and were higher at room temperature than refrigerated temperature. 8) In the cost evaluation, the cost of the developed formulas was \1,826-2,626 / kg. This was less than that of the commercially prepared formula (\3,300-4,073 / kg) and that of the imported formula (\4,250-8,720 / kg).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.305-319
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• 2000

A total of 50 diatom species and 1 subspecies belonging to 31 genera except Chaetoceros resting spores were identified in the 45 sediments subsampled from a gravity core GH98-1223 collected from the western Hokkaido Island located in the northeastern East Sea (Sea of Japan). The most dominant species is Thalassionema nitzschioides (Grunow) Hustedt, ranging 29 to 59% of the total assemblages, and most species including Denticulopsis seminae (Simonsen and Kanaya) Simonsen and Pseudoeunotia doliolus (Wallich) Grunow were less than 5% in average. Frequencies of cold-water species are generally higher than those of warm-water species and the vertical distribution of cold-water species was largely opposite to that of warm-water species in spite of ecological habitat difference. Frequency of cold-water species, D. seminae is reverse to that of P. doliolus, an indicator of the Tsushima Warm Current, which is consistent with diatom temperature value (T$_{d}$ value). The variation of T$_{d}$ values shows that the upper part of core with greater-than-average T$_{d}$ values represents postglacial warming trend. These T$_{d}$ values clearly demonstrate that the study area located in the northern part of the East Sea is gradually influenced by Tsushima Warm Current. In addition, the zig-zag variation in the lower part reflects the unstable seawater for diatom habitat. Chaetoceros resting spores indicating productivity and upwelling was 5.3 to 40%, with maximum peak at 80 cm. Chaetoceros resting spores/Chaetoceros vegetative cells, an indicator of relative amounts of biogenic material in the sediments was high at the upper 80 cm level, corresponding to the change of T$_{d}$ values. On the basis of diatom assemblages, the northeastern part of East Sea has experienced the effects of Tsushima Warm Current during the postglacial period of Holocene, which is similar to the modem climatic environment. However, the variation of P. doliolus reflects that the intensity of Tsushima Warm Current has been oscillated in the East Sea.