• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.279-290
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• 2000

To alleviate the harmful effects from contamination, the Sihwa Lake waters have been regularly fluxed out into the ocean to mix and circulate with the oceanic waters, and then allowed to flow back into the lake. In the present study, eco-environmental impacts by the outflowing contaminated lake waters to the benthic communities of the coastal zones along Kyonggi Bay were examined at three separate areas. A total of 22 groups of meiobenthic animals were commonly found in the subtidal zones of the Bay. All groups of the meiobenthic animals on the 1st and 7th days after the outflow were remarkably reduced in numbers from the selected areas examined, as compared to those observed one day before the outflow. It was also found that the community structure of meiobenthos was changed drastically: At the station near the water gate, for example, where the immediate outflow of the lake water was encountered, the benthic harpacticoids, the group observed to be one of the predominant groups before the outflow, were found to have disappeared completely. For an area that was relatively far away from the water gate, the reduction rate of meiobenthos after the outflow events was slower and more gradual than the nearer sites. An area that is the farthest from the water gate, no reduction in any of the meiobenthos group was observed. The ratio between nematodes/copepods (N/C) was remarkably changed by the outflows at the station near the water gate: One day before the outflow, the ratio was 0.7 while the ratio was 19.0 at the station near the water gate. In contrast, at the stations relatively far from the water gate, the ratio decreased one day after the outflow event, but increasing trends were observed one week later. In the tidal flats, Station 1 exhibited the common observed regional values of the ratio whereas Station 2 showed a very high ratio of 191.3. The results suggested that the contaminated lake water outflows directly effect meiobenthos in a relatively short time period and thus the meiobenthos may be a good indicator animal group for examining the effect of pollution. [Lake Sihwa, contaminat water outflow, meiobenthic animals living]

• Korean Journal of Organic Agriculture
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• v.19 no.2
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• pp.215-228
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• 2011

To establish the organic cultivation of pepper using green manure crops, this work studied the growth characteristics and yield of green manure crops, mineral composition of green manure crops, mineral uptake in shoots of green manure crops, chemical composition in soil of green manure crops, and the growth characteristics and yield of pepper in vinyl house. Shoot dry weight of green manure crops was higher level in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. Also, the roots were spread deeply into soil in Sorghum bicolor and Sorghum. Density of root-knot nematodes in rhizosphere of green manure crops was significantly more decrease in Crotalaria juncea and Sorghum than in Glycine max and Sorghum bicolor. Total nitrogen and CaO content of green manure crops was significantly higher in Crotalaria juncea and Glycine max than in Sorghum bicolor and Sorghum. $K_2O$ content was significantly higher in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. MgO content was not significant difference at all green manure crops. Cations content ratio of $K_2O$ : CaO : MgO was 3.4 : 1.4 : 1. Total nitrogen uptake in shoots of green manure crops was high level in Glycine max, Sorghum bicolor and Sorghum compared with in Crotalaria juncea. $K_2O$ and MgO uptake was significantly higher in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. Value of pH in soil of green manure crops was more increase in Crotalaria juncea and Glycine max than in Sorghum bicolor, Sorghum and control, but after cultivation of pepper pH in soil was recovered with initial soil pH before seeding of green manure crops. EC value in control, green manure crops, and pepper cultivation decreased by 44%, 15~18%, and 38~61% level, respectively, compared with initial soil of green manure crops treatment. K content in soil of control, Crotalaria juncea and Glycine max cultivation was increased by 14%, but the K content in soil of Sorghum bicolor and Sorghum decreased by 24~38%. Cation exchange capacity (CEC) in soil of Crotalaria juncea and Sorghum bicolor decreased by 11%, but CEC in soil of Glycine max, Sorghum and control increased by 11%. Harvest fruit yield was higher in Crotalaria juncea, Glycine max, and Sorghum bicolor cultivation than in control and Sorghum.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.293-299
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• 2006

A survey was conducted to find out the major plant parasitic nematode in Chrysanthemum morifolium fields in Korea from May to June in 2005. A genus of Pratylenchus was determined as the most important plant parasitic nematode based on analysis of total 50 samples from 8 cities of chrysanthemum field. Pratylenchus showed 86% occurrence rate and average numbered 1,095 per 200cc soils and 1g root. Five Pratylenchus isolates, 'Muan', 'Masan', 'Tean', 'Gumi', 'Jeongup', were selected for the molecular identification of the species of Pratylenchus, and ITS and D3-28S ribosomal DNA were amplified by PCR. For the ITS, only 'Muan' isolate was differentiated by total 1 kb PCR amplification, which was 200 bp larger than all the other isolates. There was no size variation in amplified D3-28S rDNA and all isolate represented approximately 320 bp of PCR product. Sequence data of D3-28S rDNA were analysed by MegAlign program in DNASTAR software and phylogenetic tree was constructed. Sequence homology was 100% between 'Gumi' isolate and 'Tean' isolate and 'Jeongup' isolate was also close to these isolates by 99.7% sequence homology. 'Gumi', 'Tean' group and 'Jeongup' isolate were determined to be closely related to Pratylenchus vulnus by 96.7% and 96.3% similarity in respectively. D3 sequence of 'Masan' isolate was 100% identical to P. penetrans, and 'Muan' isolate showed 99.7% similarity to P. brachyurus. This result was congruent with the branch divergence pattern shown in phylogenetic tree.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.527-533
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• 2009

This study was performed to investigate the escape of pine wood nematode (PWN), Bursaphelenchus xylophilus, from two vector species (Monochamus alternatus and M. saltuarius) through oviposition and feeding behavior. First, we checked number of PWNs escaped from M. alternatus emerged from three different cases of pine logs. In case A, healthy pine trees were cut into logs and left in pine forest infected with PWN. In case B, healthy pine trees were cut into logs, left in large screen cage, and let them oviposited by M. alternatus emerged from pine trees infested with PWN. In case C, pine trees which were harboring M. alternatus were cut into logs, and PWN was inoculated artificially. The M. alternatus adults emerged from the above three cases of pine logs were checked in the next year to know how many PWN they were harboring in their bodies. The percentages of M. alternatus harboring PWN (18.3 and 15.6%, respectively) and number of nematodes per vector ($5,713.1{\pm}9,248.3$ and $2,034.1{\pm}4,746.8$ PWNs, respectively) in case A and B logs are similar to each other. However, the percentage and the number in case C (38.3% and $20,083.1{\pm}32,188.3$ PWNs) were higher than those of case A and B. Among 52 M. alternatus adults harboring PWN from all the three cases, 20 adults (38.5%) were harboring more than 5,000 PWNs per beetle. And these 20 adults were harboring 97.9% of the total PWNs in 52 adults. Second, we checked the daily escape of PWNs from M. alternatus and M. saltuarius collected at pine forest infested with PWN. The PWN escaped from their vector body for $34.9{\pm}12.4$ days for M. alternatus, and for $23.9{\pm}16.2$ days for M. saltuarius, reaching at peak escape during the 2nd week of emergence of the two vector species. A 44.5 and 47.2% to the total PWNs escaped from vector body within 2 weeks of vector emergence for M. alternatus and M. saltuarius, respectively. The number of PWNs escaped from each vector was $3,570.6{\pm}5,189.2$ and $1,556.2{\pm}1,710.3$ for M. alternatus and M. saltuarius, respectively.

• The Korean Journal of Mycology
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• v.36 no.2
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• pp.153-162
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• 2008

Pinewood nematode (PWN) trapping by nematophagous fungi, Arthrobotrys conoides, A. dactyloides and A. oligospora and the fungal growth were characterized. The three Arthrobotrys species each was inoculated into the PWN cultured on Botrytis cinera fungal colony on potato dextrose agar (PDA). The effects of temperature, pH, PWN inoculation density and nutrients on the growth of the three Arthrobotrys spp were measured. A. conoides grew fast, 13.9 mm/day while A. dactyloides grew slow, 3 mm/day. PDA medium was the best for the fungal growth at $25^{\circ}C$ and pH 4.5. The Arthrobotrys spp growth was stimulated by 500 nematodes inoculation but not by 1000 inoculation. A. dactyloides did not grow below pH 4.5 and at high PWN density. A. conoides and A oligospora formed trapping organs with thick constricting hyphal network only when PWN present, while A. dactyloides formed the organ with circular hyphae constitutively. A. conoides formed trapping organs faster than A. oligospora did. The nematode trapping hyphae of the fungi penetrated into PNW inside to form many tiny infection bulbs and to digest the nematode. However, A. dactyloides formed a few trapping organs but no trapping was observed. Infection rate of PWN was 95% by A. conoides, 80% by A. oligospora and 92% by the combination inoculation of A. conoides and A. oligospora. In contrast A. dactyloides increased PWN density without infecton. There was no interaction effect in any combination inoculation of the three Arthrobotrys spp. A. conoides enhanced PWN infection rate by rapid hyphal growth and early trapping, while A. oligospora did it by increasing hyphal density. In conclusion A. conoides is the most effective in both hyphal growth and infection, and thus these characteristics can be utilized as a biological control of PWN.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.179-197
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• 1980

A survey was made from March 1978 through Feb. 1979 to know infection rate of parasites and incidence of diseases in 1968 cattle of 240 rearing and fattening cattle herds (1746 Korean native cattle, 186 Holstein, 34 Charolais and 2 Hereford) raising in 28 cities and counties of Gyeongbug district. The results obtained are summarized as follows: 1. The rate of nematoda infection was about 49.0% in the examined cattle. These nematodes were identified as Mecistocirrus sp., Oesophagostomum sp., Bunostomum sp., Trichostrongylus spp., Strongyloides sp. and other 3 species. Infection rate of nematoda in fattening and breeding cattle was higher than that in rearing calves, 44.3% of the positive cattle were infected with 2 to 5 species, and incidence of mixed infection was high in fattening cattle. 2. The rate of coccidal infection was 10.9%. Eimeria $z{\ddot{u}}rni$, Eimeria bovis and Eimeria bukidnonensis were mainly found in the examined cattle. The infection rates of cocidia in Holstein, breeding Korean cows, rearing Korean calves and fattening Korean cattle were 27.3%, 15.8%, 11.2% and 9.1%, respectively. 3. The rate of trematoda was 14.6% with Fasciola spp. (11.2%), Eurytrema spp. (2.0%), and Paramphistomum spp. infections (1.4%). Breeding Korean cows, fattening Korean cattle, Holstein and rearing Korean calves indicated 47.4%, 26.4%, 18.2% and 6.3% incidence of trematoda infections, respectively. of trematoda positive cattle, 76.6% were infected with Fasciola spp., 4. The rate of Theileria and Babesia infection was 62.7% in the examined cattle. Of these positive cattle 5.4% were infected with both parasites, 57.3% with Theileria, and 1.3% of rearing Korean calves and 22.6% of Holstein were found to have parasitized erythrocytes over 1.0%. 5. The incidence of diseases in 1968 cattle of 240 herds was 564 cattle (28.7%) of 154 herds (64.2%). of the diseases observed of skin occurred in 354 cattle (18.0%) of 61 herds (25.4%), diseases of respiratory system in 121 cattle (6.1%) of 34 herds (14.2%), diseases of digestive system in 38 cattle (1.9%) of 22 herds (9.2%), diseases of eye in 21 cattle (1.1%) of 13 herds (5.4%), diseases of urogenital system in 8 cattle (0.4%) of 8 herds (3.3%) and the other diseases in 24 cattle (1.2%) of 22 herds (9.2%). 6. Diseases of skin in 1968 cattle of 240 herds werds were observed in the highest incidence. Ringworm was observed in 13.3% of the examined herds, rearing Korean calves and Holstein showed high incidence. Scabies caused by Chorioptes bovis and alopecia localis along with infestation of lice (Damalinia bovis, Linognathus vituli) were observed in fattening Korean cattlein winter. 7. Diseases of respiratory system occurred frequently in rearing Korean cattle and Holstein. In the diseases of digestive system acute indigestion occurred in fattening Korean cittle, enteritis in rearing Korean calves and Holstein, and coccidiosis in rearing Korean calves maninly. 8. Infectious keratoconjunctivitis occurred in a fattening Korean cattle herd, sterility (2.0%) in breeding Korean cows, and theileriosis in Holstein calves were also occurred. In addition, poisoning and heat stroke were observed in several cattle.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.257-268
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• 2005

Meiofauna community was surveyed in the Arctic Ocean. Sediment samples were collected from six stations in the east Barents Sea and from five stations in Kongsfjorden, Svalbard during summer 2002. Eight taxa of meiofauna were identified in the Barents Sea. Meiofauna abundance ranged from 245 to 906 indiv.10 $cm^{-2}$ (mean 580 indiv.10 $cm^{-2}$) and total biomass varied from 23 and 404 ${\mu}gC10cm^{-2}$ (mean 184 ${\mug}C10cm^{-2}$) in the Barent Sea. Nematode predominated in meiofauna comprising $95.2\%$ of total abundance and $66.4\%$ of biomass. Copepods, polycheats and sarcomastigophonans were also dominant in the study area. Nine taxa of meiofauna were identified in Kongsfiorden. Meiofauna abundance ranged from 103 to 513 indiv.10 $cm^{-2}$ (mean 292 indiv.10 $cm^{-2}$) and biomass varied from 13 and 196{\mu}gC10\;cm^{-2}$ (mean 94{\mu}gC10\;cm^{-2}$) in the Kongsfiorden. Nematodes predominated in meiofauna, comprising $64.1\%$ of abundance and $64.3\%$ biomass. Copepods, polychaets, and kinorhyncha were also dominant in the study area. The meiofauna abundances from both the study areas well match with the previous reports from the various regions including the temperate areas. However the occurred taxa in the present study are only a half comparing with the reports from temperate zone. Meiofauna abundance, biomass, diversity index and species richness were much higher than in the coastal which were strongly affected by fresh water run off in the Barents Sea. The stations affected by chlorophyll had high abundance and biomass, but low diversity index and spices richness in Kongsfiorden.

• Analytical Science and Technology
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• v.27 no.5
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• pp.234-242
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• 2014

Imicyafos which is a nematicide for controlling root-knot nematodes has been registered in the Republic of Korea in 2012, and the maximum residue limits of imicyafos are set to watermelon and korean melon as each 0.05 mg/kg. Extremely reliable and sensitive analytical method is required for ensuring food safety on imicyafos residues in agricultural commodities. Imicyafos residues in samples were extracted with acetone, partitioned with hexane and dichloromethane, and then purified with florisil. The purified samples were analyzed by HPLC-UVD and confirmed with LC-MS. Linear range was between 0.1~5 mg/kg with the correlation coefficient ($r^2$) 0.99997. Average recoveries of imicyafos ranged from 77.0 to 115.4% at the spiked levels of 0.02 and 0.05 mg/kg with the relative standard deviations of 2.2~9.6%. Limit of detection and quantification were 0.005 and 0.02 mg/kg, respectively. An inter-laboratory study was conducted to validate the determination method in depth, and the results were satisfactory. All of the validation results revealed that the developed analytical method in this study is relevant for imicyafos determination in agricultural commodities and will be used as an official analytical method.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.269-277
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• 2002

Ecological studies on entomopathogenic nematodes are required to increase control efficacy against target insect pests and to obtain basic information for mass production. Thus, effect of temperature and nematode concentration on infectivity and reproduction of Steinernema carpocapsae Pocheon and that of exposure time and soil depth on infectivity were examined using Galleria mellonella larvae. Infectivity and reproduction were examined at five temperatures, 13, 18, 24, 30 and 35$^{\circ}C$ with seven concentrations, 0, 5, 10, 20, 40, 80 and 160 infective juveniles (IJs)/larva. Temperature and nematode concentration influenced infectivity and reproduction of S. carpocapsae Pocheon. Although G. mellonella larvae were killed by S. carpocapsae Pocheon at all given temperatures and nematode concentrations, mortality was higher at 24$^{\circ}C$ than other temperatures. Lethal time of G. mellonella by S. carpocapsae Pocheon was shorter with increasing temperature and nematode concentrations. S. carpocapsae Pocheon was not established in G. mellonella at 13 and $35^{\circ}C$. Time for the first emergence from G. mellonella cadaver was longer $18^{\circ}C$ (about 20 days) than 24 and $30^{\circ}C$ (about 5 days). The highest number of progenies was obtained at $24^{\circ}C$ with 80IJs/1arva, i.e., $18.8$\times$10^4$IJs were produced from a larva. In the exposure time assay, G. mellonella death was recorded in 10 minutes when 300 IJs were inoculated per larva. When S. carpocapsae Pocheon was inoculated at the rate of $10^{9}$ IJs/ha to G. mellonella at the depth of 0, 2, 5 and 10 cm of sand columns, 100% mortality and similar sex ratio were observed but number of established IJs in cadaver was decreased with deepening the soil depth. The results indicated that optimum temperature for infectivity and reproduction of S. carpocapsae Pocheon was $24^{\circ}C$ In addition, S. carpocapsae Pocheon was effective to target insects within 5 cm from the soil surface.

• Journal of Life Science
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• v.20 no.3
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• pp.411-415
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• 2010

Anisakis simplex is one of the parasitic nematodes, and has a complex life cycle in crustaceans, fish, squid or whale. When people eat under-processed or raw fish, it causes anisakidosis and also plays a critical role in inducing serious allergic reactions in humans. However, no web-based database on A. simplex at the level of DNA or protein has been so far reported. In this context, we constructed a web-based database for Anisakis research. To build up the web-based database for Anisakis research, we proceeded with the following measures: First, sequences of order Ascaridida were downloaded and translated into the multifasta format which was stored as database for stand-alone BLAST. Second, all of the nucleotide and EST sequences were clustered and assembled. And EST sequences were translated into amino acid sequences for Nuclear Localization Signal prediction. In addition, we added the vector, E. coli, and repeat sequences into the database to confirm a potential contamination. The web-based database gave us several advantages. Only data that agrees with the nucleotide sequences directly related with the order Ascaridida can be found and retrieved when searching BLAST. It is also very convenient to confirm contamination when making the cDNA or genomic library from Anisakis. Furthermore, BLAST results on the Anisakis sequence information can be quickly accessed. Taken together, the Web-based database on A. simplex will be valuable in developing species specific PCR markers and in studying SNP in A. simplex-related researches in the future.