• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.239-248
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• 1993

The purpose of this observation was to investigate the natural killer cell activities in mice Infected with pathogenic free-living amoeba, Naegleria fowleri and Acanthomoeba culbertsoni according to the infection doses, and infected with non-pathogenic free-living amoeba, Naegleria fowleri. The natural killer cell activity was examined by means of target binding capacity, active NK cell and maximum recycling capacity of the mice after inoculating free-living amoebae with low and high doses. The mice infected with 1 103, 1 105 A. culbertsoni trophozoites showed mortality rates of 6.9% and 65.5%, respectively. The mice infected with 1 104, 1 105 N.fowleri trophozoites showed mortality rates of 5.9% and 72.2%, respectively. The NK cell activities in all experimental groups increased significantly on day 1 after infection as compared with control group, and then remarkably declined thereafter, there was no difference of the cytotoxic activity of the NK cells In mice among inoculation doses of pathogenic free-living amoebae. The target binding capacities of NK cells and percentages of activated NK cells in mice Infected with pathogenic free-living amoebae were slgrlificantly Increased a day after Infection, as compared Uth control group. There was no difference of the maximal recycling capacities of NK cells in all experimental groups as compared Uth control group. There was significant difference in the cytotoxic activity and single cell cytotoxlcity of NK cells between the experimental groups infected with pathogenic free-living amoebae and that infected with non-pathogenic free-living amoebae.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.156-164
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• 1985

To elucidate the effect of splenectomy on the development of experimental primary amoebic meningoencephalitis in mice, the death rate and survival time of mice infected intranasally with Naegleria fowleri trophozoites $5{\times}10^4$ cultivated in CGVS medium were compared according to the mouse age when splenectomy was done, and post-operation until experimental infection. Immunodigusion was undergone to detect the presence of serum antibod). due to N, fowleri infecttion in mice. Polyacrylamide gel electrophoresis was done to compare the protein fractions of mouse serum in each experimental groups. In experiment I, splenectomy was done 3 weeks and infection 4 weeks after birth, the death rate of control, sham operated and splenectomized group were 100%, 85% and 95%, and the mean survival time after infection 7.3 days, 7.5 days and 7.8 days, respectively. In experiment II, splenectomy was undergone 3 weeks and infection 6 weeks after birth, the death rate of of control, sham operated and splenectomized group were 95%, 95% and 95%, and the mean survival time after infection 12.1 days, 11.5 days and 11.5 days, respectively. In experiment III, splenectomy was done 5 weeks and infection 6 weeks after birth, the death rate of control, sham operated and splenectomized group were 95%, 90% and 95%, and the mean survival time after infection 8.1 days, 8.3 days and 8.5 days, respectively. By Ouchterlony immunodigusion, anti-JV. fowleri antibody in the serum of mouse with primary amoebic meningoencephalitis was detected against a N. fowleri antigen, which was prepared by ultrasonication of N, fowleri trophozoites, each reacting two lines of precipitation. The patterns of serum fractions by polyacrylamide gel electrophoresis were different between control and sham operated groups from splenectomized group in fraction II, III and V, the sera of which were collected after N. fowleri infection. This results may be summarized as that splenectomy has no effect on the development of primary amoebic meningoencephalitis in mice.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.143-154
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• 1990

Observations were made on the differences of cell-mediated responses in mice of three infectiorl groups di여erently scheduled in their severity with pathogenic Acanthamoeba culbertseni. Infections were done by dropping $5{\;}{\mu}l$ saline suspension containing $3{\times}10^3,{\;}1{\times}10^4,{\;}or{\;}1{\times}10^5$ trophosoites, respectively. Amoebae were cultured anenically in CGV medium and inoculated into the right nasal cavity of CSH/HeJ mice aging around 6∼8 weeks, under the anesthesia by intraperitoneal injection of secobarbital. Delayed type hypersensitivity (DTH) responses in footpad and blastogenlc responses of mouse spleen cells using ($^3H$)-thymidine and the serum antibody titer were measured up to day 14 after infection, and natural killer cell activities were measured up to day, i after infection. The results obtained in this study were as follows: 1. The mice infected with $3{\times}10^3$ trophosoites showed mortality rate of 17%, and 345 in the mice infected with $1{\times}10^4$ trophozoites and 65% with $1{\times}10^5$ trophozoites. 2. In regard to DTH responses in all experimental groups, the level increased on day 7 and declined on day 14 after infection, but their differences could not be noted between infected and control groups. 3. The blastogenic responses of splenocytes treated with amoeba Iysates and lipopolysaccharides (LPS) showed no difference from the control group. The blastogenic responses of splenocytes treated with concanavalin A were declined significantly in the experimental group as compared with the control group, but the blastogenic responses of splenocytes treated with polyinosinic acid were not different from the control group. There was also no difference among three infected groups. 4. The cytotoxic activity of the natural killer cells was activated on day 1 after infection and declined to the level of control group on day 2 in all experimental groups. On day 5 after infection, the natural killer cell cytotoxicity was significantly suppressed as compared with the control groups. 5. The serum antibody titers of the infected mice increased after day 7, but there was no statistical difference between the three infected groups. In summary of the results, there was no difference in cell-mediated immune responses of three experimental groups scheduled with different infection intensities. But there was a significant difference in cell$.$mediated immune responses between infected and control mice. It is considered that cell-mediated immune responses should be involved in murine model infected with A. culbertsoni.

• Parasites, Hosts and Diseases
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• v.26 no.1
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• pp.39-44
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• 1988

A pathogenic free-living amoeba, Naegleria fowleri, is a causative protozoan parasite of primary amebic meningoencephalitis in human and experimental animals. It is known that humoral and cellular immunity contribute as the defence mechanism of host against this organism. Recently splenectomy has been argued on its effect on host defence mechanisms. The present study was aimed to observe the enact of immunization in splenectomized mice. For immunization, $5~10{\times}10^5$ trophozoites of Naegleria fewleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and $5~10{\times}10^4$ of ameba trophozoites were intranasally inoculated for infection after splenectomy and/or immunization. ELISA technique was applied for the detection of seum IgG antibody levels. Experimental animals were divided into 4 groups; I. splenectomized and immuniEed; ll. splenectomized only; III. immunized only; IV. not splenectomized nor immunized. The results obtained were as follows: 1. Mortality rates of splenectomized and immunized mice in group I (38.1%) and immunized only in group III (25.0%) were lower than those of not immunized mice in group II (50%) and control group, IV (46.4%). 2. Survival times of mice in group I, II, III and IV were $20.1{\pm}3.6$, $17.3{\pm}4.5$, $20.4{\pm}7.0$ and $19.6{\pm}7.6$ days respectively, and there were no significant differences between them. 3. ELISA values (absorbance at 492nm) of group I (1, $10{\pm}0.29$) and group III ($1.31{\pm}0.28$) were significantly higher than that of group IV($0.24{\pm}0.37$) at day 31 of infection (p<0.05). Conclusively, it is presumed that humoral immunity against N. fowleri may operate as ever, after immunization, even though the mouse was splenectomized.

• Parasites, Hosts and Diseases
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• v.32 no.1
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• pp.27-34
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• 1994

The results of fecal examination for helminth eggs and protozoan cysts in Seoul Paik Hospital during 1984-1992 are reported. Fecal specimens of a total of 52,552 out- or in- patients were examined by formalin-ether sedimentation and/or direct smear method. The overall egg Positive rate of helminths was 6.5% and the cyst Positive rate of Protozoa 2.5%. The egg positive rate (number of positive cases) for each species of helminth was; Clonorchis sirensis 3.2%(1,667) , Trichuris trichiura 2.0%(1,089), Metqsonimw yokogawai 1.2% (613), Ascaris lumbricoides 0.2% (100), Trichostrongylus orientalis 0.1% (34), Taenin spp. 0.05% (28), Hymenolepis nana 0.03% (181), hookworms 0.03% (17), Poragonimlrkf westermani 0.02% (12), Echinostoma spp. 0.03% (12), Enterobius uermiculans 0.02% (10), Strongyloides stercora;is (larvae) 0.01% (6) , and Diphyllobothrium latum 0.004% (2). The cyst positive rate (number of positive casesl for each protozoan was; Entamoebc coli 1.1% f5881, Snnolimox nana 0.8% (402), Ginrdin lomblia 0.3% (173) , Entamoeba histo;utoca 0.3% (164), and Trichomonos hominis (trophozoites) 0.004% (2). Viewing from the data of 9 years, it was evident that the prevalence of soil-transmitted helminths such as A. Lumbricoines and T. trichiuro has been decreasing remarkably, while that of snail transmitted helminths such as C. sinenris and intestinal protozoans has not.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.343-353
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• 2006

Giardia intestinalis infections arise primarily from contaminated food or water Zoonotic transmission is possible, and at least 7 major assemblages including 2 assemblages recovered from humans have been identified. The determination of the genotype of G. intestinalis is useful not only for assessing the correlation of clinical symptoms and genotypes, but also for finding the infection route and its causative agent in epidemiological studies. In this study, methods to identify the genotypes more specifically than the known 2 genotypes recovered from humans have been developed using the intergenic spacer (IGS) region of rDNA. The IGS region contains varying sequences and is thus suitable for comparing isolates once they are classified as the same strain. Genomic DNA was extracted from cysts isolated from the feces of 5 Chinese, 2 Laotians and 2 Koreans infected with G. intestinalis and the trophozoites of WB, K1, and GS strains cultured in the laboratory, respectively. The rDNA containing the IGS region was amplified by PCR and cloned. The nucleotide sequence of the 3' end of IGS region was determined and examined by multiple alignment and phylogenetic analysis. Based on the nucleotide sequence of the IGS region, 13 G. intestinalis isolates were classified to assemblages A and B, and assemblage A was subdivided into A1 and A2. Then, the primers specific to each assemblage were designed, and PCR was peformed using those primers. It detected as little as 10 pg of DNA, and the PCR amplified products with the specific length to each assemblage (A1, 176bp; A2, 261 bp; B, 319 bp) were found. The PCR specific to 3 assemblages of G. intestinalis did not react with other bacteria or protozoans, and it did not react with G. intestinalis isolates obtained from dogs and rats. It was thus confirmed that by applying this PCR method amplifying the IGS region, the detection of G. intestinalis and its genotyping can be determined simultaneously.

• Applied Microscopy
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• v.3 no.1
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• pp.1-16
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• 1973

A combined cytochemical and electron microscopic study was carried out for the demonstration of acid phosphatase activities in trophozoites of E. histolytica. and E. gingivalis. E. histolytica(YS-27) strain was isolated from liver abscess of 72-year-old man in September 1969, and E. gingivalis (YS-215) strain was collected from gingival crevice of 41-year-old man in January 1972. The amoeba strains were maintained by subculture on diphasic medium, and used throughout the study. The results are summarized as follows; 1. In E. histolytica, the reaction products were distributed evenly over the entire surface of plasma membrane, whereas E. gingivalis showed no activity of acid phosphatase on the plasma membrane, except in the portion of the uroid-like structure. 2. In the cytoplasm, various reaction precipitates were observed in vacuoles of both amoebae; vacuole limiting membrane, vacuole membrane and its contents and lysosome-like structure. Strong enzyme active contents but membrane reaction negative vacuoles were conspicuous in E. gingivalis. Endoplasmic reticulum showed a moderate activity. 3. Granule-like acid phosphatase reaction product was demonstrated in the nucleoplasm of E. gingivalis, but it was negative in E. histolytica.

• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.11-25
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• 1976

Studies on pathogenicities and developmental stages of Nosema apis (Zander, 1909) were carried out through artificial infection to Nosema free honey bees with various levels of spores isolated from local honey bee colony. The results obtained were summarized as follows: 1. The clinical symptoms were observed as dysentery, enteritis of mid-gut (enlargement and decoloration), crawling posture and shortening of the longevity of worker bees in the rearing honey bee colony inoculated with the spores. 2. Number of spores harvested from laboratory rearing honey bees were progresively increased to 4 weeks after inoculation. The regression equations and coefficients of correlations to various spore levels were as follows in each treatment colony. Colony 1. ($$1,000{\times}10^4spores/ml$$) $$y_{c1}=471{\times}10^{4}x+454{\times}10^4(r=0.65^*$$) Colony 2. ($$500{\times}10^4spores/ml$$) $$y_{c2}=340{\times}10^{4}x+207.8{\times}10^4(r=0.99^{**}$$) Colony 3. ($$100{\times}10^4spores/ml$$) $$y_{c3}=150{\times}10^{4}x+84.2{\times}10^4(r=0.99^{**}$$) Colony 4. ($$10{\times}10^4spores/ml$$) $$y_{c4}=13.8{\times}10^{4}x+13{\times}10^4(r=0.98^{**}$$) 3. Average longevity of worker bees artificially infected with Nosema apis was shortened as 21.7~43.8% compare to the control. (p<.05, p<.01) 4. The spores which were isolated from honey bee colony infected with Nosema disease were ovoid or spherical form, and measured, as a rule, from $4.7{\mu}m$ to $6.1{\mu}m$ (mean $5.3{\mu}m$) in length and from $2.4{\mu}m$ to $3.2{\mu}m$ (mean $2.9{\mu}m$) in width. 5. In the mid-gut of honey bees, the spore was progresively germinated and became trophozoite stage. The trophozoites were grown to meronts and their binary fission were begun. The divided two sporoblasts were developed to the spores which had elastic membrane. The new spores were shed in excreta of honey bees 10~15 day after inoculation at $25{\pm}2$ centigrade. 6. The ultrastructure of spore membrane consisted of three layers, such as, outer, middle and inner layer. The sporoplasm consisting lamellar structure occupied only anterior part of the spore and was often extended to posterior direction where definite vacuoles and a polar filament was able to detect.

• Parasites, Hosts and Diseases
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• v.32 no.4
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• pp.259-266
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• 1994

The role of macrophages was observed In intranasally infected CSH/HeJ mice with trophozoites (3 ×105) of Acnnthomoeba culbertsoni which was a kind of free-living amoebae inducing meningoencephalitis in human and experimental animals. The mortality was 60% in the group of intraperitoneally injected mice with silica (0.5 mg/0.5 ml). It was much higher than that of 10% in the group of amoeba infected mice without silica administration. The phagocytic index of peritoneal macrophages co-cultured with Toxoplasma gondii was estimated daily. In contrast to the control and amoeba infected group which didn't show significant fluctuation of the phagocytic indices, the silica administrated group revealed under 3% until day 3, and gradual increase up to 24.7% in day 5 which was same level of amoeba infected group without silica administration. The level of interleukin- lb (IL- lb) measured by ELISA was the highest in the amoeba infected group without silica injection and the lowest in the amoeba infected group with silica administration. In the test of the amoebicidal activity of mice peritoneal macrcphages Dl uitro, silica administration revealed reducing effect on amoebicidal activity of macrophages. In conclusion, macrophages were proven to play a significant role in defense mechanism against the development of experimentally induced Acnnthamoebo menigoencephalitis.

• Parasites, Hosts and Diseases
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• v.35 no.2
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• pp.119-126
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• 1997

Acanthnmoebn sp. YM-4 is simitar to A. culbertsoni based upon morphological characteristics of trophozoites and cysts. However, based on other characteristics, pathogenicity to mice, in uitro cytotoxicity and isoenzyme patterns, Acanthomoebo sp. YM- 4 was quite different from A. culbertsoni. Restriction fragment length polymorphism (RFLP) analysis of mtDNA is useful in the classification of members belonging to the genus Acanthcmoebn. Therefore, in this study, RFLP analysis of Acnnthcmoeba mtDNAs was accomplished using five restriction enzymes: Hnelll, Hinull, Clcl, Pudl and ScE. Each restriction enzyme produced approximately 3-15 fragments (range: from 0:6 kip to 34.4 kbp) . The mtDNA genome size, calculated by the summation of restriction fragments, averaged 46.4 kbp in Acnnthamoeba sp. YM-4,48.3 kbp in A. culbertsoni and 48.8 kbp in A. polyphaic, respectively. Digested mtDNA fragments of Accnthcmoeba sp. YM-4 contained nine and seven same size fragments, respectively, from a total of 67 and 69 fragments observed in A. culbertsoni and A. polyphcgn. An estimate of the genetic divergence was 10.1% between Acanthamoebc sp. YM-4 and A. culbertsoni, and 9.9% between Acanthamoebn sp. YM-4 and A. polyphcga.