• Journal of fish pathology
• /
• v.36 no.2
• /
• pp.263-275
• /
• 2023

Chum salmon (Oncorhynchus keta) is a species which returns to Korea for spawning and was produced as seed production at the Fisheries Resources Agency located in Uljin-gun, Gyeongsangbuk-do to preserve the species. However, farmed chum salmon showed symptoms of bacterial infection. Therefore, in this study, bacteria were isolated to identify the causative agent from chum salmon in October 2021. The isolated bacteria were identified based on the sequences of 16S rDNA, rpoD (RNA polymerase sigma factor σ⁷⁰), and vapA (A-layer) genes. Also, salinity-growth curve, biochemical characterization, antibiotic susceptibility test, and pathogenicity analysis were performed in four strains. As a result, four isolated strains were identified as Aeromonas salmonicida subsp. salmonicida. Additionally, the bacterial strains showed a decrease in growth as the salt concentration increased in the medium. All of the isolated strains exhibited γ-hemolysis, and the same biochemical properties. In the antimicrobial susceptibility test, all strains showed an inhibition zone of 40 to 44 mm for oxolinic acid, flumequine, and florfenicol. Pathogenic factors were assessed by RT-PCR at the mRNA level, and found that the four strains expresses the outer membrane ring of T3SS (ascV), inner membrane ring of T3SS (ascC), vapA, enterotoxin (act), and lipase (lip) genes which are well known to significantly contribute to the pathogenicity of A. salmonicida. The results of this study can be used as basic data to prevent A. salmonicida subsp. salmonicida occurring in sea-chum salmon in the future.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.2
• /
• pp.123-133
• /
• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.

• Journal of Korean Society of Forest Science
• /
• v.89 no.5
• /
• pp.618-629
• /
• 2000

This study was carried out to investigate ecological niche of Quercus acuta communities in Bogildo-island from July to October, 1998. This island is occupied by a subtropical evergreen broad-leaved forests. The study on community ecology of Q. acuta, mostly dominant species of subtropical forests, is very important for successful forest management. Sampling areas were selected in 16 quadrats, dominated by Q. acuta to examine the vegetation characteristics(plant identification, D.B.H.) and environmental elements (microtopography, altitude, slope degree, aspect, illumination and soil physicochemical properties). On the basis of data from field surveys, importance values were calculated for the dominance of Q. acuta and volume growth was analyzed by tree ring widths. The results obtained were as follows ; 1. The lists of vascular plants in the investigations were identified as 54 families, 91 genera, 113 species, 9 varieties, 1 formae. It appeared that 45 kinds were evergreen, 6 kinds(Camellia japonica, Ligustrum japonicum, Eurya japonica, Smilax china, Trachelospermum asiaticum var. intermedium, Carex lanceolata) were commonly observed in all plots and 5 species(Cinnamomum japonicum, Ardisia japonica, Cymbidium goeringii, Dryopteris bissetiana, Viburnum erosum) were most highly observed in all plots(over 80%). 2. The dominating species per strata were, Quercus acuta, Castanopsis cuspidata sp. Quercus salicina, Pinus thunbergii, Prunus sargentii in tree layer, Camellia Japonica, Ligustrum japonicum, Quercus acuta, Eurya japonica, Castanopsis cuspidata sp. in subtree layer, Camellia japonica, Ligustrum japonicum, Smilax china, Cinnamomum japonicum, Viburnum erosum in shrub layer and Trachelospermum asiaticum var. intermedium, Ardisia japonica, Carex lanceolata, Camellia japonica(seedlings), Quercus acuta(seedlings) in herb layer, all in descending orders. 3. Quercus acuta could be suggested as shade intolerant tree, considering the distribution in southern, western, nothern and eastern slopes in the descending orders. 4. Mean relative illumination in the forest is 0.89 % and it is relatively low in brightness. 5. Sustainment of Quercus acuta community couldn't be confirmed by judging from their reverse J curve in even-aged forest, as shown in D.B.H. distribution analysis. 6. The result of annual ring width analysis(mean ; 2.44 mm) showed three stages, such as a gentle increasing(1~12 year ; 2.04 mm), a relatively steep increasing(13~22 year ; 2.95 mm) and decreasing or stagnating(23 year after ; 2.41 mm).

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.1
• /
• pp.29-34
• /
• 1974

On a newly reclamed acidic Song-jong soil (soil of a member of fine loamy, mesic family of Hapludults) an experiment was carried out to find out the proper measure of the improvement of soil fertility with soybean as test crop. Results are summarized as follow: 1. Application of compost (1 ton/10a), lime (lime requirement)and fused phosphate (equivalent to 5% of the phosphate fixation coefficient)resulted in the increase of soybean yield by 93.3% over the check plot (N: 6kg/10a, $P_2O_5$: 9kg/10a, $K_2O$: 6kg/10a). The application of fused phosphate at the level of 5% of phosphate fixation coefficient N (6kg/10a) and K(6kg/10a) brought the yield increase by 62.7% over the check plot. However, although the pH of the soil was adjusted to 7.0 by liming, the application of lime with moderate dose of phosphate ($P_2O_5$: 9kg/10a) did not increase the yield of soybean significantly. And the application of fused phosphate at the level of 5% of phosphate fixation coefficient increased the available soil P from 14 ppm to around 100 ppm as tested after harvest. 2. Application of compost (1 ton/10a) increased the organic matter content of soil by 0.8% when tested after harvest. While, the application of rice straw (0.5 ton/10a) did not alter the soil organic matter content. The CEC of the soil tested after havest found incereased significantly by the addition of lime and compost. 3. Plant analysis revealed that the $K_2O/Ca+Mg$ is better correlated with the yield than the absolute concentration of $K_2O$ in plant tissue. Between the concentration of $P_2O_5$ in plant tissue and the yield of soybean, a typical C-curve relationship was observed, indicating that in this particular soil, phosphate was the primary growth liming factor.

• Journal of Food Hygiene and Safety
• /
• v.23 no.2
• /
• pp.157-162
• /
• 2008

Enterobacter sakazakii was initially referred to as yellow-pigmented Enterobacter cloacae and reclassified in 1980. E. sakazakii infection cause life-threatening meningitis, septicemia, and necrotizing enterocolitis in infants. Powdered infant formula (PIF) and baby foods may be the important vehicle of E. sakazakii infection. It has been reported that E. sakazakii was isolated from PIF and sunsik ingredients produced in Korea. Some infants have been fed sunsik as a weaning diet. Therefore, it is necessary that this organism should be inactivated on preparing PIF and sunsik at homes and in hospitals. The cocktail of three Korean E. sakazakii strains (human, sunsik and soil isolates) were used to investigate the inactivation of this organism with hot water at 50, 60, 65, 70 and $80^{\circ}C$ and microwave heating for 60, 75, 90, 105 and 120 sec. Reconstituted PIF and sunsikwere inoculated with cocktailed vegetative cells of E. sakazakii at 6 log CFU/mL. Thermal inactivation of vegetative cells of E. sakazakii were achieved by reconstituted PIF and sunsik with hot water at $60^{\circ}C$ or greater and with microwave heating at 2,450 MHz for 75 sec or longer. Considering that biofilm formation of E. sakazakii was adapted to survive the dry environment that is PIF and sunsik and thermal resistance increased, it is suggested that inactivation of E. sakazakii was used by hot water at $70^{\circ}C$ or greater and microwave heating for 90 sec or longer. Reconstituted PIF and sunsik were inoculated with cocktailed vegetative cells of E. sakazakii at 2 to 3 log CFU/mL to investigate the growth curve of this organism and stored at 5, 10, 15, 20, 25, 30 and $35^{\circ}C$. Viable counts slightly changed at 5, $10^{\circ}C$ during 48 h but grew at $15^{\circ}C$ or greater. Considering that E. sakazakii is able to grow in infant formula milk at refrigerator temperature, reconstituted PIF and sunsik that are not immediately consumed should be discarded or stored at refrigeration temperatures within 24 h.

• Horticultural Science & Technology
• /
• v.29 no.5
• /
• pp.474-481
• /
• 2011

Potato late blight caused by the fungus Phytophthora infestans is one of the most vital diseases damaging the potato plant. It is for this reason that breeding potato cultivars resistant to late blight is now becoming a major concern around the world. The B3C1 clones has been introduced by the Highland Agriculture Research Center, RDA. The clones which came from International Potato Center in 2005 have a durable resistance to late blight. The clones were bred under a short-day condition in Peru. However, there was still no report on the adaptability of these clones to the long-day condition in Korea. Therefore, this study was conducted to evaluate the late blight resistance and major agronomic characteristics of B3C1 clones under Korea's long-day condition. This study was also done to generate genetic resources for developing new varieties resistant to late blight. In this study it was found out that in naturally infested field with P. infestans, AUDPC (area under disease progress curve) values of all B3C1 clones were significantly lower than those of the control varieties, 'Superior', 'Atlantic', and 'Haryeong'. It was found out that B3C1 clones had a high level of resistance to late blight and that they could be used as genetic resources to breed potato varieties with late blight resistance. However, several undesirable characteristics such as extremely late maturity, excessive growth of stems and stolons, and production of tubers that cannot easily be removed from the stolons were also observed. Among the twenty B3C1 clones, two clones, LB-8 (CIP393077.159) and LB-11 (CIP393371.159), were selected for cultivating at the highland area of Korea. Two B3C1 clones were crossed with Korean breeding lines and clonal selection for the progenies is still in progress.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.29 no.3
• /
• pp.187-196
• /
• 2009

The objectives of this study were to evaluate the different cutting dates on the changes of feed quality among five cereals (barley, wheat, rye, triticale and oat) for whole crop silage. Field trials were conducted at paddy field in Yesan, Chungnam Province and the aerial parts were clipped 10 days from 15 March to 15 June. Changes of acid detergent fiber (ADF) content in relation to different cutting dates was described by a quadratic curve for 5 winter cereals crops. ADF content reached a maximum at 5 days after heading in barley cultivar 'Youngyang', 7 days in wheat 'Keumkang', 18 days in rye 'Gogu', 1 days in triticale 'Shinyoung' and 10 days in oat 'Samhan'. Neutral detergent fiber (NDF) content were linearly increased as growing after overwintering and stagnated or slightly decreased after heading. The crude protein were linearly decreased throughout the growth period of 5 whole crop cereals. Digestible dry matter (DDM) content were decreased from early stages to heading and subsequently increased as grain filling. Relative feed value (RFV) for 5 crops were decreased as growing and subsequently increased as grain filling after heading. Barley cultivar for only forage use 'Youngyang' were lower at ADF and NDF content and higher at DDM and RFV after heading than those of other cereals for forage use. So, barley for whole crop silage was a good crop with high feed quality and high proportion of spikes compared with other winter cereal crops. Wheat cultivar for grain 'Keumkang' were higher at crude protein than those of other four cereals from overwintering to maturing and were higher at DDM and RFV after heading than those of rye, triticale and oat. Rye cultivar with cold tolerant and high fresh yielding 'Gogu' were highest at ADF and NDF content and lowest at DDM content and RFV. So, rye was a crop with low quality for forage use compared to other winter cereal crops. Triticale cultivar with flourishing and high yielding 'Shinyoung' was intermediated between barley and rye, and were linearly increased at DDM yield by different cutting dates. Oat cultivar with cold tolerant and high tillering 'Samhan' were lower at ADF and NDF content and higher at crude protein before heading, but after heading, there are not especially advantages compared to barley, wheat or triticale.

• Parasites, Hosts and Diseases
• /
• v.27 no.4
• /
• pp.261-270
• /
• 1989

The present study is intended to observe the chronologic changes of experimental sparganosis by histopathological observation and detection of circulating anti-sparganum IgG antibody using ELISA. Each of 25 mice was infected with aye spargana, and they were examined after 1, 2, 4, 10 weeks or 6 months from infection. The followings are summarized results. - 1. The plerocercoids were detected in the subcutaneous tissue of the trunk, neck or axilla, but a few often extended into the skeletal muscle. The recovery rates were 72% at the first week, 80% at the second week, 95% at the fourth week, 92% at the tenth week and 100% at .the sixth month. The larvae grew slowly in both length and weight until 6 months. 2. Histopathologically, most of the larvae were observed alive in the soft tissue or skeletal muscle. Numerous eosinophils, neutrophils, Iymphocytes and plasma cells were infiltrated focally around the worms by the second week, but they surrounded the worms to form a layer of inflammatory reaction after 4 weeks of infection. Also histiocytes and fibroblasts began to appear around the inflammatory cells at 4 weeks. After 10 weeks, the worms encircled by a thin fibrous layer were found. After 6 months, the worms were surrounded by either fibrous tissue or active inflammatory cells. The inflammation looked more severe in the tracks left by the worms, rather than around the worms. 3, The level of anti-sparganum IgG antibody in the serum showed an increase by the fourth week, and a rapid and continuous increase was observed thereafter by the tenth week after infection. The high level of the IgG antibody was maintained up to 6 months forming a plateau curve. The present results suggest that the tissue reaction and antibody production in subcutaneous sparganosis become distinctive by the fourth week after infection.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.13 no.2
• /
• pp.180-192
• /
• 2010

Purpose: To evaluate the feasibility and usefulness of the waist circumference-to-height ratio (WHTR) in screening for obesity in Korean children and adolescents. Methods: Data, including body mass index (BMI), waist circumference (WC), and height, were obtained from the national growth surveys for children and adolescents in 2005. The WHTR was calculated dividing WC by height in subjects 2~18 years of age. Overweight and obese were defined by BMI percentiles for age and gender. The receiver operating characteristic (ROC) analysis was performed to find out the optimal cutoff values of WHTR that matched BMI-determined overweight and obesity using the STATA program. The area under the curve (AUC), a measure of diagnostic power, of WHTR was compared to WC. The influence of age on WHTR was analyzed by the SAS program. Results: The WHTR significantly decreased with age, and had less correlation with age in the 6~18-year-old age group than the 2~5-year-old age group. Furthermore, the WHTR also had less correlation with age than WC in the 6~18-year-old age group. The AUC of WHTR in identifying overweight and obesity was significantly higher than the AUC of WC in the 6~18-year-old age group. The optimal cutoff values were 0.51 in boys and 0.49 in girls for obesity, and 0.48 in boys and 0.47 in girls for overweight, with all having the AUC>0.9. The optimal cutoff values of WHTR had a higher sensitivity for diagnosing obesity than WC${\geq}$90th percentiles. Conclusion: The WHTR is an easy, accurate, and less age-dependent index with high applicability in screening for obesity in children and adolescents.

• Proceedings of the Korean DIstribution Association Conference
• /
• 2002.05a
• /
• pp.31-59
• /
• 2002

Recently there are many changes of logistics environment Such as integrated logistics information system, the rapid growth of the domestic and international small package express service and third party logistics with Electronic Commerce. At this time it is very important to deliver to customers the goods sold through EC speedy, accurately and safely. That is to say, the role of small package express service is very important at EC times. The bottlenecks of small package express service in the circumstances of EC are the weakness of EC operating company and small package express service provider the shortage of distribution centre and cargo terminal, the shortage of skilled man with related small package express service etc. So, I suggested that for activation of EC it is necessary to strengthen the strategic alliances, introduce GPS and use the third party logistics positively in the side of small package express service provider. And it is necessary to prepare for the settlements of traffic problems, support the introduction of integrated logistics service, logistics information system, deregulate restriction such as weight limit of vehicles in the side of the government. And to government support throughout extending nation's SOC, deregulation, support to small package express service terminal, permit to stopping & parking in downtown, abolishing a no passing zone, permit to being employed foreigner. Also this service involves ensuring that the product will arrive when wanted, and in an undamaged condition.