• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.293-299
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• 1985

This study is to verify the protective ability against experimental Naegleria meningoencephalitis by immunization with Naegleria fowleri in mice. Naegleria fewleri, strain 0359, and Naegleria gruberi, strain EGB, were used in this study, and cultured in CGVS medium akenically. Inbred BALB/C mice, weighing about 20g, were immunized by three intraperitoneal injection of $1{\times}10^6$ N. fowleri trophozoites at the interval of one week. This N. fowleri trophozoites antigen was fixed with 5% formaldehyde. N. fowleri trophozoites from culture were homogenized with soiicator at $4^{\circ}C$ as monitored by phase contrast microscopy, and their membrane and cell content preparations were made for the immunization of mice. Their inoculation dose in volume was equivalent to the $1{\times}10^6$ trophozoites in each injection for immunization. And N. gruberi trophosoites, whieh was fixed with 5% formaldehyde, were also used for immunisation. Mice were inoculated intranasally with $5{\times}10^4$ N. fowleri trophozoites in a 511 suspension under anesthesia by as intraperitoneal injection of about 1 mg secobarbiturate. Nervousness, rotation or sluggish behaviour were observed in the mice which were infected with N. fewleri. Necrotic lesion was demonstrated in the anterior portion of brain, especially in the olfactory lobe. The inflammatory cell infiltration with numerous H. fowleri trophozoites was noticed. This pathological changes were more extensive in the control than in the experimental groups. Mice were dead due to experimental primary amoebic meningoencephalitis that developed between 8 days and 23 days after inoculation. Mortality rate of the mice was low in the immunized experimental group. Mean survival time, which is the survival duration of mice from the infection to death, was prolonged significantly in the immunized mice except in the mice immunized with JV, fowleri membrane. Even in the mice immunized with N. gruberi, survival time was delayed. In summary, the effectiveness of immunization is demonstrated in terms of protective immunity against Naegleria meningoencephalitis in mice.

• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.241-246
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• 1985

The epidemiological status of ascariasis was analyzed in 8 rural villages in Korea, through observation of its epidemiological parameters such as prevalence, worm burden and basic reproductive rate. Total 978 inhabitants were subjected to stool examination and recovery of worms after chemotherapy with pyrantel pamoate. The results were as follows: 1. The worm positive rate in each village was 16.5~79.5%, while the egg positive rate was 9~18% lower, 3.3~66.7%. The average worm burden (among all inhabitants) ranged from O. 21 to 8. 44 by villages and the frequency of cases with each worm burden showed negative binomial distributions with 'k' values of O. 38-0. 54. 2. The prevalence rates (worm) in each village was almost identical with the theoretical ones from Anderson and May's equation; $p=1-(1+M^*/k)^{-k}$, where 'p' is worm prevalence and '$M^*$' equilibrium average worm burden. The basic reproductive rate 'R' was calculated from 1.03 to 2.11. lt is suggested that, although 'R' in lower endemic areas is approaching to the breakpoint of reinfection (R=1), control programs of ascariasis in Korea should be continued until it becomes below the level nationwidely.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.35-48
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• 1996

Non-biting midges fchironomidae, Dipteral are one of the largest insect families, which are distributed worldwidely and are found in nearly all types of inland waters. They are known to be aggressive inhalant allergens which cause allergenic diseases. In this study, the crude antigens of Chironomus SavipLumn adults which are most widely distributed in Korea were extracted. and their allergens were analysed with the sera from experimentally sensitized mice. The mice were immunized with $1{\;}\mu\textrm{g}{\;}or{\;}10{\;}\mu\textrm{g}$ of the crude antigens, respectively, and the specific serum IgE levels were measured by both ELISA and passive cutaneous anaphylaxis (PCA) techniques. The highest levels of both total IgE and chironomid-specific IgE were found in the mouse sera obtained after 9 weeks of the first infection with $1{\;}\mu\textrm{g}$ crude antigen. The crude antigen was separated into 16-18 protein bands on gel by SDS-PAGE. The crude extract was assessed by SDS-PAGE/immunoblot analysis. One IgE-binding band (65 kDa) was detected by developing with colorimetric substrate, and 4 IgE-binding bands (65, 52, 35 and 25 kDa) by developing with CSPD chemiluminescent substrate. The SDS-PAGE gel of the crude extract of chironomid adults was equally cut into 30 pieces and each of them was eluted to isolate proteins by molecular weight, and the allergenicity of each eluate was assessed by applying P-K test on rats. Proteins of 65, 35 and 15 KDa showed the highest P-K titer (${\times}512$) which was 16 times higher than that of the crude extract (${\times32}$). The P-K titer of 52 kDa protein was also 4 times higher ($128{\times}$) than that of the crude extract, whereas the 25 kDa protein poorly responded, which seemed not antigenic. In conclusion, the present result in mice demonstrated that adults of Chironomus fcuiplumus, a predominent species in Korea, cause allergenic diseases and the main allergens are 65, 52, 35 and 15 kDa proteins, of which 65 kDa protein seems to be a main allergen.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.409-416
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• 2010

An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.191-198
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• 1998

The responses to antifolales of ToxopLasmc Bondii were investigated by measuring the dihydrorolate redLlctase (DHFR) activity. quantity of DHFR mRNA, and single-strand conformational polymorphism (SSCP) pattern. Pyrimethamine (PYM) and methotrexate (MTX) were tested ds anlifolates. When T. gondii was treated wish PYM, the viability was decreased by the increasing concentration of PYM. DHFR activity tended to increase as the passage proceeded. and the quantity of mRNA expressed was also increased according to passages. The viability of 7. gonnii was decreased by the increasing concentration of MTX, but it was maintained over 40% up to $100{\;}{\mu\textrm{m}}$ MTX. DHFR activity was 77.4% in the 1st passage ($1{\;}{\mu\textrm{m}}$). 82.2% in the 4th passage ($10{\;}{\mu\textrm{m}}$), and 141.3% in the 7th passage ($100{\;}{\mu\textrm{m}}$) But no changes were detected in SSCP pattern of T gondii rxposvd to FYM and MTX. both. These results suggested that the response of T gondii to FYN was rofulalcd by transrriptional level and that, in MTX. the viability of T. gonnii was derived from increasing DHFK activity.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.51-58
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• 1987

Tegumental ultrastructures of Echinochasmus japonicus were observed by scanning electron microscopy. The worms were recovered from albino rats which were experimentally infected with the metacercariae obtained from Pseudorasbora parva. Followings are summarized findings. 1. The worms were minute and plumpy gourdshaped with attenuated anterior and round posterior end. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. 2. Head crown was armed with 24 collar spines which were embedded in cytoplasmic pockets. The spines were arranged in a row with an interruption at dorsomedian line, however, the 2nd and the 4th spines were outstretched more than others. Oral and ventral suckers were muscular with numerous type II sensory papillae, and genital pore opened between the two suckers. 3. Tegumental spines were spade-shaped with broad base and pointed tip. They were compact in ventra-lateral tegument or dorsal surface of anterior body. They were not found between the two suckers and dorsal surface of posterior body. 4. Two types of sensory papillae, uni-ciliated (Type I) and roundly swollen sensory papillae (Type II), were observed. The type I papillae were chiefly distributed on ventral surface of tegument and type II were on the lips of suckers. Arrangement of collar spines, shape and distribution of tegumental spines or sensory papillae are regarded as characteristic features of E. japonicus.

• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.267-278
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• 1991

The natural killer (NK) cell activity of splenocytes and recycling capacity of NK cells were observed by combining the $^{51}Cr-release$ cytotoxicity assay and single cell cytotoxicity assay against YAC-1. The ICR mice were infected intranasally with Naegleria fewleri, that is a pathogenic free-living amoeba. The mice infected with $1{\times}10^5$ trophosoites showed mortality rate of 76.7% and mean survival time of 12. 9 days. The cytotoxic activity of NK cells in infected mice was significantly higher than that of non-infected mice during the period between 12 hours and day 3 after infection, and highest on day 1. The target-binding capacity of NK cells in infected mice was not different from that of non-infected ones. Maximal killing potential and maximal recycling capacity were remarkably increased in infected mice as compared with the control. The results obtained in this observation indicated that elevated NK cell activity in mice infected with N. fowieri was not due to target-binding capacity of NK cells but due to the increased activity of NK cells and increased recycling capacity of individual NK cells.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.1-6
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• 1987

This study was to observe the changes of blastogenic responses of splenic Iymphocytes to T-cell mitogens, N. fcwleri Iysate and concanaualin A, and serum antibody titer during the course of experimental PAM in mice. Naegleria fcwleri, strain 0359, was cultured in the CGVS medium axenically and inoculated intranasally with $7{\times}10^4$ trophozoites for the development of experimental PAM in mice. The amoebae were subjected to ultrasonication and centrifuged at 20,000g for 60 minutes, and filtered through $0.2{\mu\textrm{m}}$ filter membrane. The supernatant, N. fcwleri Iysate, was used as T-cell mitogen, and antigen for ELISA. The serum antibody was examined by ELISA using peroxidase conjugate. Two hundred ${\mi}l$ of $10^6$ splenocytes in RPMI 1640 containing 0% fetal calf serum were added to each well of a microtiter plate. To each well was added T-cell mitogens, $100{\mu}g/ml$ of N. fowleri Iysate or $4{\mu}g/ml$ of con. A, and the plates were incubated for 42 hours at $37^{\circ}C$ in 5% $CO_2$ incubator. Cultures were pulsed with of $methyl-(^3H)-thymidine$ 6 hour before harvesting. The mean blastogenic response of the splenocytes to N. fewleri Iysate was reduced, whereas that to con. A was also reduced up to on day 11 after infection. Both of these results were statistically significant compared with those of uninfected control group. The serum antibody titers were increased gradually up to day 15. The results indicated that there was an impairment of the blastogenic response of splenocytes to N. fowleri Iysate during the acute course of experimental PAM in mice.

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.331-340
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• 1993

This study investigate the epidemiological feature of Metagonimus infection in Kangwon-do (province). The average Infection rate of the surveyed inhabitants was 7.8% (83 positives out of 1, 067 examinees) by stool examination; male, 11.4% and female, 3.2%, respectively. The egg positive rate in residents in the Som river area was 7.3%, that of the Chuchon river area 6.3%, the Pyongchang river area 12.8%, the Tong river area 3.8%, the Hongchon river area 9.8%, and the Ohsip stream area of Samchok 8.0%,respectively. The average metacercarial infection rate of genus Metagonimus in the fish was 81.0% (256 positives out of 318 fish). The infected fleshes were Zacco platypus. Zacco teminki, Opswiichthys biens, Squdidis sp., Corqssius carassius, etc. in western Kangwon-do Meanwhile, in the Ohsip stream area of Samchok-gun, eastern costal Kangwon-do, the infected fish were Plecoglossus altivelis and Tribolodon hokonensis. The rats and dogs are infected with the metcercanae obtained from Zacco platypus and Opsariichthys biens, adult worms collected were Miyata type of Metagonimus with some M. takahashii. When infected with metacercariae from Plecoglossus ltivelis, Metagonimus yokogowai was only found. M. yoogawai and Metagonimus Mlyata type were fecund together in Tribolodon hakonenis in Ohsip stream area of Samchok, in the eastern Kangwon-do. The intestinal flukes of genus Metogonimus in western Kangwon-do were Miyata type of MetQnonimuT and M. takahashii transmitting mainly by Zacco platypus and Opsariichtys bidens as a source of infection. In the eastern part of Kangwon province (Ohsip stream area of Samchok), M. yokogowai was mainly distributed by P. altivelis and T. hakonesis, but some T. hakonensis harbored the metacercariae of Miyata type of Metagonimus with those of M. yokogawai.

• Parasites, Hosts and Diseases
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• v.32 no.3
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• pp.185-194
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• 1994

The present study was undertaken to assess the role of cytokines in the activation of peritoneal macrophages from Toxoplasma-infected mice. Peritoneal macrophages from Toxoplasma-infected mice (10 cysts of Beverley strain/mouse) were harvested 8 weeks after infection, and incubated with the mitogen-induced lymphokine, recombinant mouse $interferon-{\gamma}(IFN-{\gamma})$, recombinant mouse tumor necrosis $factor-{\alpha}{\;}(TNF-{\alpha})$ alone or in combination with 4$IFN-{\gamma}(IFN-{\gamma}/TNF-{\alpha})$ for 24hr at 37^{\circ}C$, 5% $CO_2$. Macrophage activation was measured by the amount of $H_20_2{\;}and{\;}N0_2^{-}$ production, and antiToxoplasma activities of macrophages. $IFN-{\gamma}{\;}or{\;}IFN-{\gamma}/TNF-{\alpha}-treated$ macrophages from Toxoplasma-infected mice revealed significantly higher $H_20_2$ production than resident macrophages from Toxoplasma-infected mice. The production of $N0_2^{-}{\;}by{\;}TNF-{\alpha}-,{\;}IFN-{\gamma}-{\;}or{\;}IFN-{\gamma}/TNF-{\alpha}-treated$ macrophages from Toxoplasma-infected mice were significantly higher than that by resident macrophages, whereas lymphokine-treated group produced similar amount as that produced by resident macrophages. Anti-Toxoplasma activities of cytokinetreated macrophages from Toxoplasma-infected mice were Significantly higher than those of resident macrophages. $IFN-{\gamma}-treated$ macrophages were significantly increased production of $H_20_2{\;}and{\;}N0_2^{-}$, and anti-Toxoplasma activities of macrophages between normal and Toxoplasma-infected mice, whereas the other cytokine-treated groups were not significant differences between them. These data suggested that IFN-{\gamma}was the only one of cytokines capable of significantly activating the peritoneal macrophages from Toxoplasmainfected mice.