• Journal of fish pathology
• /
• v.13 no.1
• /
• pp.37-44
• /
• 2000

CT(Sodium N-chloro-para toluenesulfonamide, Chloramine-T) known to be a strong oxidative agent was investigated to use as a candidate of disinfectant in the marine aquaculture industry by the analysis of the bactericidal activity against different aquatic microorganisms. One hundred percent mortality appeared at and above 16 ppm CT in sea water in flounder, the predominant species in the marine aquaculture of Korea, when exposed for 48hr. However, bactericidal activity was appeared to be very effective, and all different species of the fish pathogenic bacteria exposed to CT of less than 2 ppm in sea water were dead within 15 min. It allowed us to confirm that CT could be a very effective disinfectant to protect the spread of fish pathogenic bacteria derived from diseased fish or sea water in marine aquaculture. High concentration(10 ppm) with longer exposing time(24 hrs) was required for the algicidal activity of CT, at which concentration might induce the acute toxicity against fish, however, restricted the expanded use of CT for the elimination of zooplanktons at phytoplanktons in marine farms. Moreover the bactericidal activity of CT inhibited almost completely in the present of more than 10 ppm of organic materials pointed out that quality of the culturing sea water should be considered carefully for the application CT to the aquatic farms as a therapeutic agent.

• Pediatric Infection and Vaccine
• /
• v.9 no.2
• /
• pp.222-229
• /
• 2002

Human infection with the lung fluke Paragonimus westermani has become rare in Korea. Human paragonimiasis is caused by eating raw fresh-water crayfishes or crabs infected with larval metacercariae. Recently, we experienced three cases of pulmonary paragonimiasis in a family. They ate raw fresh-water crayfishes that lived in a stream in Wolchulmountain. All the parients had hypereosinophilia and pulmonary infiltrates with pleural effusion or hydropneumothorax, which did not improve on antibiotics. Ingestion of raw crayfishes was a clue for paragonimiasis. Positive results were shown both on intradermal skin test and ELISA for Paragonimus westermani specific IgG. After treatment with praziquantel, the patients showed an improvement. This is the first familial human paragonimiasis, reported from Wolchulmountain in Chonnam Province where there had been no previous cases of paragonimiasis.

• Research in Plant Disease
• /
• v.13 no.1
• /
• pp.34-39
• /
• 2007

Lichen thalli of Dirinaria applanata heavily colonized on the twigs of dead or dying Rhododendron trees in Solok island, Jeonnam province in Korea. Pathogenesis of the lichen on the trees was investigated to find out the possibility of lichen as a causal agent. Histological examination of the lichen colonized twigs was attempted with differential staining technique. Lichen-forming fungus colonized only on the surface of bark and there was no direct penetration of fungal hyphae into the plant tissues. Symbiotic algae of the lichen was also examined. The isolated algal cells were inoculated on artificially induced wounds of the healthy trees. Histological examination of the inoculated tissues showed that some algal cells were successfully colonized inside the tissues without any pathogenic symptoms, even 2 months later, The extract of the lichen thalli was also examined using 10% of DMSO solution. Treated tissues showed no pathogenic symptoms, even 4 weeks later. The results suggested that the lichen was not directly involved in the death of the trees.

• Parasites, Hosts and Diseases
• /
• v.27 no.3
• /
• pp.161-170
• /
• 1989

The proteases of Toxoplasma gcndii were purified partially and characterisrd for some biochemical properties including various chromatographic patterns, major catalytic classes, and conditions to promote the activity of these enzymes. When Toxoplasma extract was incubated with 3H-casein at various pH, peak hydrolysis of casein was observed at pH 6.0 and at pH 8.5. Proteasfs working at pH 6.0 and at pH 8.5 were purified partially by conventional methods of chromatographies of DE52 anion rxchange, Sephadex G-200 gel permeation, and hydroxylapatite chromatography. Partially purified enzymes were tested by site-specific inhibitors and promotorf. The protease working at pH 6.0 was inactivated by iodoacetamide with LDso of 10-5 M and promoted by dithiothreitol, while the protease working at pH 8.5 was inhibited by phenylmethylsulfonyl fluoride with LD50 of 10-5 M and was Promoted by ATP (excess ATP beyond 2 mM inhibited the activity reversely). The protease of pH 8.5 had the activity of ATPase which might exert the energy to its action. Therefore the former was referred to as a cysteinyl acid protease and the latter, ATP-dependent neutral serine protease.

• Parasites, Hosts and Diseases
• /
• v.26 no.4
• /
• pp.263-274
• /
• 1988

Recent patterns of infection with digenetic larval trematodes in fresh- water and brackish-water ask were studied in three locations of the river Taewha during the period from April to October, 1988, and compared with the data reported previously in the same river, 0(16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh.water fish. The metacercariae of Echinochasmus sp. , Metacercaria hasegawai and Metagonimus yokogawai were found from 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, whereas their intensity of infection was found lowered in 3 species, Ccreobagrus brevicorpus, Gnathopogon atromaculatus, and Funtungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Flecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. The encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh- water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.

• Parasites, Hosts and Diseases
• /
• v.27 no.1
• /
• pp.1-8
• /
• 1989

Serodiagnosis of parasitic infections is widely used, since parasites or their eggs are not always detected by ordinary methods. The sensitive tests such as ELISA are highly dependent on the purity of antigens used. To solve this problem. many workers have tried to find species-specific components of antigens, The present study was performed to determine the antigenic profile of crude saline extracts of 3, 5, 8 and 12-week old p. westermani worms, which were collected from experimentally infected cats, based on SDS-PAGE and immunoblot technique. The results were as follows: 1. The SDS-PAGE showed at least 30 Protein bands ranging from 229 kDa to 10 kDa molecular weight. The protein components of p. wsstermani changed chronologically during its developmental period. The 229 kDa band was recognized only in 12-week old worms ($$SEP_{l2}$). 2. Analysis by ELISA showed a significant increase in antibody levels at 3 weeks in infected cats using crude saline extract antigens ($SEP_3,{\;}SEP_5,{\;}SEP_8,{\;}SEP_{l2}$). 3. By EITB using $SEP_3$ and $SEP_5$ infected cats recognisea major protein bands with molecular weight of 60, 35, 28, 25 or 21 kDa at 3~12 weeks of infection, and 3 additional antigens, 19, 13 and 10 kDa, were detected at 8~12 weeks of infections. 4. Using $SEP_8$ 5 antigens, 91, 85, 31, 25 and 21 kDa, were consistently detected by all infected sera tested. In addition, 3 antigens of lg. 13 and 10 kDa were detected at 8~12 weeks of infection. Using $SEP_12$, similar results were obtained with that by using $SEP_8$ and 1 additional antigen of 229 kDa, specifically reacting with the sera from 12 weeks of in(traction, was recognized.

• Parasites, Hosts and Diseases
• /
• v.27 no.1
• /
• pp.35-40
• /
• 1989

It is well known that the duodenum of mice or rats infected with Fibricoln seoulensis shows atrophy of villi (shortening, blunting, widening, fusion) and hyperplasia of crypts. This study was performed to observe healing process of .these pathological changes after deworming with anthelmintic treatment. Albino rats infected each with.1,000 metacercariae of F. seeulensis were treated with single dose of 10 mg/kg praziquantel on day 15 post·infection. On day 1, 3, 5, 7, 15, 21 and 28 after the treatment, they were sacrificed and their duodenums were histopathologically studied. Control (uninfected) rats showed their normal finger-like projections of duodenal villi and well arranged crypts. In comparison, untreated (infected) contiols revealed severe mucosal changes characteristic of villous atrophy and crypt hyperplasia in their duodenum. The damaged duodenal mucosa was found to restore its normal morphology after praziquantel treatment; until day 3 post-treatment the mucosa was severely atrophied; on day 5 long and slender villi sometimes appeared among the fused and stout ones; after day 15 the villi were in their normalising process. From this experiment, it was shown that the mucosal changes in the duodenum of rats caused by F. seoulensis infection were completely reversible in 21∼28 days after anthelmintic treatment.

• Parasites, Hosts and Diseases
• /
• v.27 no.1
• /
• pp.15-22
• /
• 1989

To observe antibody changes after praziquantel treatment in paragonimiasis, a total of 46 serum samples from 13 serologically diagnosed patients was collected for 4~28 months. The specific antibody (IgG) levels were measured by enzyme- linked immunosorbent assay (ELISA). All but one patient who needed retreatment became symptom-free within a week. Antibody levels were dropped near to or below a cut-off absorbance (abs.) of 0.25 in varying intervals from 4 to 18 months. Of 9 patients who were retested within 3 months, 5 revealed temporary elevation of antibody level. After the elevation, the levels be낙an to decline slowly to negative ranges. If treated earlier after symptoms developed, the temporary elevation did not occur and intervals to negative conversion were shorter. By sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) /immunoblot, antigen-antibody reactions in individual patient faded gradually without significant changes in reacting antigen bands.

• Parasites, Hosts and Diseases
• /
• v.26 no.4
• /
• pp.229-238
• /
• 1988

In vitro culture of Toxoplasma gondii in HL-60 cells and cell-mediates immunity against Toxoplasma in dimethylsulfoxide(DMSO) -induced HL-60 cells, i.e., differentiation into granulocytes, were pursued. HL-60 calls were treated with various concentrations of DMSO, and 1.3%(v/v) for 3 day incubation was chosen as the optimal condition icy differentiation into granulocytes. The degree of differentiation was assayed in physiological and functional aspects in addition to morphological point. When treated with 1.3% DMSO for 3 days, HL-60 cells did not synthesiar DNA materials beyond background level, and showed active chemotactic response to chemotactic peptide, formal-methionyl-leucyl-phenylalanine(FMLP). Morphologically promyelocytes of high nuclearlcytoplasmic(NIC) ratio changed to granulocytes of relatively low WJC ratio. The relationships between HL-60 cells or DMSO-induced HL-60 cells and Toxoplasma were examined after stain with Giemsa and Buorescent dye (acridine orange). HL-60 cells did not show any sign of torso- plasmacidal activity but showed intracellular proliferation of Texoplasma to form rosette for 72 hr co-culture. In contrast, OMSO-induced HL-60 cells phagocytosed Toxoplasma within 1 hr, and performed a process of intracellular digestion of Toxoplasma thereafter. With the above results, it is suggested that phagosome-Iysosome fusion is one of the critical events for the parasitism by Toxoplasma or for susceptibility of host cells. The in vitro culture system of this study has offered a defined condition to study the protozoan parasite-host cell interactions.

• Parasites, Hosts and Diseases
• /
• v.27 no.1
• /
• pp.57-66
• /
• 1989

A scanning electron microscopic study was performed to observe the tegumental ultrastructures of Paragonimus iloktuenensis according to its developmental stages. The metacercariae were obtained from the liver of the brackish water crab, Sesarma dehaani. Juvenile and adult p. iloktsuenensis were recovered from the experimental rats on 2, 4 and 8 weeks after infection. The findings were summarized as follows: 1. The encysted metacercariae were charaeteristically gourd-shape, with their whole body surface beset with numerous spade-shape spines. The Barge, type II sensory papillae (non-ciliated round swellings) were arranged along the rim of the oral and ventral suckers, 11~12 and 6~8 in numbers respectively, 2. Two-week old juvenile worms, recovered chieay from the liver of the experimental rats, were slender in body shape: with their ventral sucker near the anterior one-third level. The distribution of tegumental spines was less dense than in the encysted metacercariae. The spines were with 1~2 pointed tips and 3~.4 longitudinal splits. Numerous ciliated knob-like, type I papillae were observed in both sides of the oral sucker, and 6 large, type If papillae were arranged along the rim of the ventral sucker. 3. Four week old worms, recovered from the thoracic cavity and/or lung parenchyme of the experimental rats, were thicker than wide in body configuration, and their ventral sucker was located near the anterior one.fourth level. The tegumental spines at ventral surface were grouped, each group with 3~5 aggregated ones. The type I and type II papillae (small-sired) were distributed chiefly around the rim of two suckers. 4. Adult (eight-week old) worms, recovered from the capsules in the lung parenchyme, were very stout, and covered densely with bearfoot like spines. At dorsal surface, cobblestone-like cytoplasmic processes were well-developed, with many tegumental spines embedded in them. It was observed in this study that the tegument of p. iloktsuenensis continued to change and differentiate as the worms grew to be adults.