• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.447-453
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• 2016

Acanthamoeba, a free-living amoeba, is widely distributed in the environment, water sources, soil, dust, and air. It can cause keratitis in contact lens wearers with poor hygiene and also fatal granulomatous amebic encephalitis (GAE) in immunocompromised hosts. The aim of this study was to gain some insights into the distribution and genotypes of the potentially pathogenic species of Acanthamoeba present in water sources in north of Iran. Total 43 Acanthamoeba species were isolated from 77 water samples taken from different water sources within the Mazandaran province in Northern Iran (Sari city and suburbs). Isolates were identified based on cyst and trophozoite morphological characteristics as well genetics. PCR fragments corresponding to the small-subunit 18S rRNA gene were sequenced for 20 of 43 positive isolates. The results revealed that 83.3% of sequenced isolates belonged to the T4 genotype and the rest belonged to the T2 genotype. Our results indicated that Acanthamoeba is widely distributed in Sari city. As the incidence in Iran of amoebic keratitis has increased in recent years, the exact estimation of the prevalence of this amoeba and its predominant genotype may play a crucial role in prevention of the disease. Sari city has several rivers, seashores, and natural recreational amenities, which attract visitors during the year. This is the first report of Acanthamoeba genotypes from water sources in Sari city, Mazandaran province of Iran, and the results suggest that more attention is needed to protect the visiting population and immunocompromised individuals.

• Parasites, Hosts and Diseases
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• 제37권1호
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• pp.27-32
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• 1999

A total of 542 children under 10 years of age, admitted to the Seoul National University Children's Hospital, was examined for antibody titers of Toxoplasma gondii using indirect latex agglutination (ILA) test. Among them, 7.7% showed positive titers higher than 1:32, without significant difference between males (7.3%) and females (8.5%). The seropositive rate increased with age although the statistical significance was negligible (0.05

• Parasites, Hosts and Diseases
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• 제55권5호
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• pp.505-512
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• 2017

Toxoplasma gondii cathepsin C proteases (TgCPC1, 2, and 3) are important for the growth and survival of T. gondii. In the present study, B-cell and T-cell epitopes of TgCPC1 were predicted using DNAstar and the Immune Epitope Database. A TgCPC1 DNA vaccine was constructed, and its ability to induce protective immune responses against toxoplasmosis in BALB/c mice was evaluated in the presence or absence of the adjuvant ${\alpha}-GalCer$. As results, TgCPC1 DNA vaccine with or without adjuvant ${\alpha}-GalCer$ showed higher levels of IgG and IgG2a in the serum, as well as IL-2 and $IFN-{\gamma}$ in the spleen compared to controls (PBS, pEGFP-C1, and ${\alpha}-GalCer$). Upon challenge infection with tachyzoites of T. gondii (RH), $pCPC1/{\alpha}-GalCer$ immunized mice showed the longest survival among all the groups. Mice vaccinated with DNA vaccine without adjuvant (pCPC1) showed better protective immunity compared to other controls (PBS, pEGFP-C1, and ${\alpha}-GalCer$). These results indicate that a DNA vaccine encoding TgCPC1 is a potential vaccine candidate against toxoplasmosis.

• Genomics & Informatics
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• 제14권2호
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• pp.53-61
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• 2016

Toxoplasma gondii is an intracellular Apicomplexan parasite and a causative agent of toxoplasmosis in human. It causes encephalitis, uveitis, chorioretinitis, and congenital infection. T. gondii invades the host cell by forming a moving junction (MJ) complex. This complex formation is initiated by intermolecular interactions between the two secretory parasitic proteins-namely, apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2) and is critically essential for the host invasion process. By this study, we propose two potential leads, NSC95522 and NSC179676 that can efficiently target the AMA1 hydrophobic cleft, which is a hotspot for targeting MJ complex formation. The proposed leads are the result of an exhaustive conformational search-based virtual screen with multilevel precision scoring of the docking affinities. These two compounds surpassed all the precision levels of docking and also the stringent post docking and cumulative molecular dynamics evaluations. Moreover, the backbone flexibility of hotspot residues in the hydrophobic cleft, which has been previously reported to be essential for accommodative binding of RON2 to AMA1, was also highly perturbed by these compounds. Furthermore, binding free energy calculations of these two compounds also revealed a significant affinity to AMA1. Machine learning approaches also predicted these two compounds to possess more relevant activities. Hence, these two leads, NSC95522 and NSC179676, may prove to be potential inhibitors targeting AMA1-RON2 complex formation towards combating toxoplasmosis.

• Parasites, Hosts and Diseases
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• 제25권2호
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• pp.199-208
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• 1987

The chemotherapeutic efficacy of trimethoprim-sulfamethoxazole ($Bactrim^{\circledR}$) in mice experimentally infected with Toxoplasma gcndii was evaluated. The average survival days and survival rate of mice infected intraperitoneally with $1{\times}10^5$ trophozoites and treated with $Bactrim^{\circledR}$ were compared with those of untreated group. The hematologic findings of blood samples of experimental mice were observed for comparison of side elects between $Bactrim^{\circledR}$ and pyrimethamine ($Daraprim^{\circledR}$), the latter of which has been one of the favorable drugs for the treatment of toxoplasmosis. The results are summarized as follows: 1. $Bactrim^{\circledR}$ showed a strong evidence of potent anti-Toxoplasma activity. The survival rate of mice administered with 24 mg of $Bactrim^{\circledR}$ per mouse per day for 7 days, was 83.3%, and the rate was increased to 100% in mice administered with two-fold concentrated dose of the drug. 2. The average numbers of white blood cells (W.B.C.) in the mouse groups treated with $Bactrim^{\circledR}$ or $Daraprim^{\circledR}$ were more increased than those only infected with T. gondii. The mice treated with $Daraprim^{\circledR}$ however, showed remarkably decreased numbers of W.B.C. as compared with those treated with $Bactrim^{\circledR}$ . 3. The average numbers of red blood cells (R.B.C.) and platelets both in the drug-treated and untreated T. gondii-infected mice were decreased as compared with normal mice. The numbers of R. B. C. in $Daraprim^{\circledR}-treated$ mice, however, were more decreased than in $Bactrim^{\circledR}-treated$ mice. 4. The average levels of hemoglobin both in the drug.treated and untreated T. gondii-infected mice were decreased, compared with normal mice. But there was no difference in the levels of hemoglobin between $Bactrim^{\circledR}$ and $Daraprim^{\circledR}-treated$ groups. In conclusion, trimethoprim.sulfamethoxasole ($Bactrim^{\circledR}$) was proven to be effective and safe for the treatment of murine toxoplasmosis. The efficacy was comparable with pyrimethamine ($Daraprim^{\circledR}$), but bone marrow depression was less severe with $Bactrim^{\circledR}$ treatment.

• 한국자원식물학회지
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• 제27권5호
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• pp.415-420
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• 2014

임상적으로 감염 시 치명적인 뇌염이나 유산을 일으키는 병원체인 톡소포자충의 치료제로 주로 사용되고 있는 설파디아진이 사용되고 있으나, 이들 약물들은 부작용과 약물 내성에 의한 치료 실패 사례들이 자주 보고되고 있다. 이러한 이유로 톡소포자충에 대한 새로운 치료제의 개발 필요성이 대두되고 있으며, 합성 화학약물들에 비교하여 부작용이 적고 안전성이 높은 천연물들을 원료로 한 톡소포자충의 치료가 모색되고 있다. 본 연구는 약용 작물로서 보존 활용가치가 높을 것으로 예상되는 염생식물인 해홍나물 에탄올 추출물을 이용하여 톡소플라즈마 원충에 대한 항원충 효과를 알아 보고자 수행 되었다. 본 연구 결과, 해홍나물 에탄올 추출물은 톡소포자충의 치료제로 임상에서 실제 톡소포자충의 치료로 사용되고 있는 설파다이아진의 선택성 2.06 보다 해홍나물 에탄올 추출물의 선택성이 6.63으로 매우 높은 것을 알 수 있었다. 또한 해홍나물 에탄올 추출물이 용량 의존적으로 톡소포자충에 감염된 HeLa 세포수를 감소시키는 것을 확인하였다. 톡소포자충에 감염된 세포에 해홍나물 에탄올 추출물을 농도별로 처리하여 감염 세포들의 형태학적 변화를 관찰한 결과, 해홍나물 에탄올 추출물의 적용 농도가 높아질수록 톡소포자충 감염에 의한 세포의 형태적 변화를 감소시키는 것을 알 수 있었다. 이러한 결과로부터 해홍나물은 향후 톡소포자충 치료에 합성 약물인 설파다이아진을 대체할 수 있는 내성이 없는 천연물 소재로 개발될 수 있을 것으로 판단되었다.

• 한국자원식물학회지
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• 제29권1호
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• pp.26-31
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• 2016

임상적으로 감염 시 치명적인 뇌염이나 유산을 일으키는 병원체인 톡소포자충의 치료제로 주로 사용되고 있는 설파디아진이 사용되고 있으나, 이들 약물들은 부작용과 약물 내성에 의한 치료 실패 사례들이 자주 보고되고 있다. 이러한 이유로 톡소포자충에 대한 새로운 치료제의 개발 필요성이 대두되고 있으며, 합성 화학약물들에 비교하여 부작용이 적고 안전성이 높은 천연물들을 원료로 한 톡소포자충의 치료가 모색되고 있다. 본 연구는 약용 작물로서 보존 활용가치가 높을 것으로 예상되는 차전초 에탄올 추출물을 이용하여 톡소포자충 대한 항원충 효과를 알아보고자 수행 있다. 본 연구 결과, 차전초 에탄올 추출물은 톡소포자충의 치료제로 임상에서 실제 톡소포자충의 치료로 사용되고 있는 설파디아진의 선택성 0.4 보다 차전초 에탄올 추출물의 선택성이 4.5으로 매우 높은 것을 알 수 있다. 본 차전초 에탄올 추출물이 용량 의존적으로 톡소포자충에 감염된 HeLa 세포수를 감소시키는 것을 확인하였다. 톡소포자충에 감염된 세포에 차전초 에탄올 추출물을 농도별로 처리하여 감염 세포들의 형태학적 변화를 관찰한 결과, 차전초 에탄올 추출물의 적용 농도가 높아질수록 톡소포자충 감염에 의한 세포의 형태적 변화를 감소시키는 것을 알 수 있다. 이러한 결과로부터 차전초는 정상 세포에 독성이 적고 톡소포자충의 억제 능력이 우수하여 항톡소토자충 선택성이 높은 소재임을 알 수 있었다. 향후 차전초 추출물 소재는 현재 톡소포자충 치료에 사용되는 합성 약제의 부작용이 문제를 해결하고 효능과 안전성이 높은 천연물 소재로 개발될 수 있을 것으로 판단되었다.

• 대한수의사회지
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• 제9권2호
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• pp.3-22
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• 1965

In 1908, Toxoplasma was demonstrated for the first time by Nicolle. Since then a number of isolations from birds and other mammalians including human were reported by many workers. Each strain of Toxoplasma isolated from various animals was identified as

• Parasites, Hosts and Diseases
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• 제56권5호
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• pp.429-435
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• 2018

Toxoplasma gondii is a ubiquitous protozoan parasite responsible for causing toxoplasmosis. Preventive measures for toxoplasmosis are currently lacking and as such, development of novel vaccines are of urgent need. In this study, we generated 2 virus-like particles (VLPs) vaccines expressing T. gondii rhoptry protein 4 (ROP4) or rhoptry protein 18 (ROP18) using influenza matrix protein (M1) as a core protein. Mice were intranasally immunized with VLPs vaccines and after the last immunization, mice were challenged with ME49 cysts. Protective efficacy was assessed and compared by determining serum antibody responses, body weight changes and the reduction of cyst counts in the brain. ROP18 VLPs-immunized mice induced greater levels of IgG and IgA antibody responses than those immunized with ROP4 VLPs. ROP18 VLPs immunization significantly reduced body weight loss and the number of brain cysts in mice compared to ROP4 VLPs post-challenge. These results indicate that T. gondii ROP18 VLPs elicited better protective efficacy than ROP4 VLPs, providing important insight into vaccine design strategy.

• Parasites, Hosts and Diseases
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• 제53권6호
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• pp.749-753
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• 2015

Toxoplasma gondii atypical type II genotype was diagnosed in a pet peach-faced lovebird (Agapornis roseicollis) based on histopathology, immunohistochemistry, and multilocus DNA typing. The bird presented with severe neurological signs, and hematology was suggestive of chronic granulomatous disease. Gross post-mortem examination revealed cerebral hemorrhage, splenomegaly, hepatitis, and thickening of the right ventricular free wall. Histologic sections of the most significant lesions in the brain revealed intralesional protozoan organisms associated with malacia, spongiform changes, and a mild histiocytic response, indicative of diffuse, non-suppurative encephalitis. Immunohistochemistry confirmed the causative organisms to be T. gondii. DNA isolated from the brain was used to confirm the presence of T. gondii DNA. Multilocus genotyping based on SAG1, altSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico markers demonstrated the presence of ToxoDB PCR-RFLP genotype #3 and B1 gene as atypical T. gondii type II. The atypical type II strain has been previously documented in Australian wildlife, indicating an environmental transmission route.