• Parasites, Hosts and Diseases
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• 제56권1호
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• pp.33-39
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• 2018

Intestinal parasitic infections remain a major public health problem in many parts of Thailand, particularly in rural areas. This study aimed to determine the prevalence of intestinal parasitic infections and associated risk factors among the people living in Huai Sai sub-district, Bang Khla district, Chachoengsao Province, central Thailand. A cross-sectional survey was carried out from June 2017 to August 2017 which included a total of 224 participants. Stool samples were examined using a simple direct smear and formalin ethyl acetate concentration technique. Association between risk factors and intestinal parasitic infections was assessed using multivariate logistic regression analysis. The overall prevalence of intestinal parasitic infections was 16.1%. Soil-transmitted helminth infections (14.3%) were more common than protozoan infections (1.8%). The most common intestinal parasites were hookworms (6.7%) followed by Strongyloides stercoralis, (5.0%), Ascaris lumbricoides (1.3%) and Trichuris trichiura (1.3%). Entamoeba histolytica/dispar (1.0%), Giardia intestinalis (0.4%), and Blastocystis hominis (0.4%) were the protozoans identified. A high prevalence of infections was found in male participants of ${\geq}40years$ who raised dogs in the households and did not wear boots while working fields. Multivariate analysis showed a significant association of intestinal parasitic infections with gender with the adjusted odds ratio (OR) of 2.4 and 95% confidence interval (CI) of 1.1-5.2 (P=0.020). The results showed a high prevalence of soil-transmitted helminth infections among adults in rural communities which were particularly apparent regarding the skin-penetrating species of nematodes. A greater focus on intervention is required by improving sanitation and personal hygiene to prevent the spread of intestinal parasitic infections.

• 대한수의학회지
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• 제50권4호
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• pp.273-277
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• 2010

The objective of this study was to investigate the infection rate of gastro-intestinal tract parasites on acquired laboratory nonhuman primates, Vervet monkey, Cynomolgus monkey, and Rhesus monkey acquired from Japan and China. These monkeys have been acclimating at an individual housing condition after our legal quarantine period. We examined 133 fecal samples to investigate parasitic infection using direct smear and formalin-ether-sedimentation technique. As a result, total parasitic infection rate was 33.8% (n = 45/133) for all monkeys. Two species of macaques, cynomolgus and rhesus, were infected with Trichuris trichiura (4), Giardia lamblia (4) and Balantidium coli (41). Vervet monkeys, which had been controlled by individual housing system for a long time, were clear for parasitic infection. The protozoan, Balantidium coli was one of the most frequently detected in these monkey colonies. Double infection was noted in only 4 monkeys and involved with Trichuris trichiura and Balantidium coli. Serious clinical symptoms were not observed in the most of the infected monkeys, but the monkeys infected by Giardia lamblia showed intermittent or chronic watery diarrhea. Consequently, the prophylactic anthelmintic treatment and periodic monitoring are essential to preserve the SPF colonies in the laboratory facility.

• Parasites, Hosts and Diseases
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• 제45권1호
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• pp.11-18
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• 2007

Recent in vitro studies have revealed that a certain Mycobacterium can survive and multiply within free-living amoebae. It is believed that protozoans function as host cells for the intracellular replication and evasion of Mycobacterium spp. under harmful conditions. In this study, we describe the isolation and characterization of a bacterium naturally observed within an amoeba isolate acquired from a contact lens storage case. The bacterium multi-plied within Acanthamoeba, but exerted no cytopathic effects on the amoeba during a 6-year amoebic culture. Trasnmission electron microscopy showed that the bacteria were randomly distributed within the cytoplasm of trophozoites and cysts of Acanthamoeba. On the basis of the results of 18S rRNA gene analysis, the amoeba was identified as A. lugdunensis. A 16S rRNA gene analysis placed this bacterium within the genus Mycobacterium. The bacterium evidenced positive reactivity for acid-fast and fluorescent acid-fast stains. The bacterium was capable of growth on the Middlebrook 7H11-Mycobacterium-specific agar. The identification and characterization of bacterial endosymbionts of free-living protozoa bears significant implications for our understanding of the ecology and the identification of other atypical mycobacterial pathogens.

• Parasites, Hosts and Diseases
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• 제51권2호
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• pp.237-241
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• 2013

Giardia lamblia is recognized as one of the most prevalent parasites in dogs. The present study aimed to establish a loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of G. lamblia from dogs. The fecal samples were collected and prepared for microscopic analysis, and then the genomic DNA was extracted directly from purified cysts. The concentration of DNA samples of G. lamblia were diluted by 10-fold serially ranging from $10^{-1}$ to $10^{-5}ng/{\mu}l$ for LAMP and PCR assays. The LAMP assay allows the amplification to be finished within 60 min under isothermal conditions of $63^{\circ}C$ by employing 6 oligonucleotide primers designed based on G. lamblia elongation factor 1 alpha ($EF1{\alpha}$) gene sequence. Our tests showed that the specific amplification products were obtained only with G. lamblia, while no amplification products were detected with DNA of other related protozoans. Sensitivity evaluation indicated that the LAMP assay was sensitive 10 times more than PCR. It is concluded that LAMP is a rapid, highly sensitive and specific DNA amplification technique for detection of G. lamblia, which has implications for effective control and prevention of giardiasis.

• 한국해양학회지
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• 제29권4호
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• pp.376-382
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• 1994

인공적으로 폐쇄된 생태계인 인천항 선거내에서 동물플랑크톤 군집의 계절적 출현 을 조사하기 위하여 1989년 12월부터 1991년 12월까지 매월 5개 정점(선거내 4개 정점 및 선거밖 1개 정점)에서 정량 채집을 하였다. 늦은 가을과 이른 겨울에 원생동물이 대량 출현한 것을 제외하면 요각류가 선거 안팎 모두에서 우점하고 있었다. 우정종은 Oithona davisae, Acartia bifilosa, Paracalanus crassirostris, Noctiluca scintillas and Tintinnopsis tubulosa 등이었는데 1990년 여름에는 산소부족으로 인 하여 선거내에서 A. bifilosa를 제외하고는 모두 소멸하였다. 1990년 여름을 제외하고 는 선거 안팎의 동물플랑크톤 출현량 차이가 뚜렸하지 않았으나 선거밖에서 연중 출현 종수가 많았는데 특히 Centropages abdominalis, Pseudodiaptomus marinus, Tortanus forcipatus, T. spinicaudatus 등 4종의 요각류는 선거 밖에서만 출현하였다.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.134-139
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• 2004

Hybrid cluster protein (HCP) was investigated because of its unique iron-sulfur clusters, which have been found in bacteria and archaea. Here, HCP homologous proteins from the third domain, 'eukarya'(3 amitochondriate protozoans, Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis), were identified. All three amitochondriate protozoan HCPs (GlHCP, EhHCP, and TvHCP) belonged to Class I on the basis of two key characters, the cysteine spacing, Cys-(Xaa)₂Cys(Xaa)/sub 7-8/-Cys(Xaa)/sub 5/-Cys, and the absence of N-terminal deletion characteristic to the Class III. In phylogenetic analysis performed with amino acid sequences of 3 eukaryal, 5 bacterial, and 4 archaeal HCPs, the maximum likelihood (ML) tree indicated that TvHCP was clustered with Class I HCPs, whereas the other two HCPs (GlHCP and EhHCP) formed an independent clade with a high bootstrapping value (96%) not belonging to any previously recognized HCP class. In spite of the relatively lower bootstrapping value (61%), the position of the new eukaryal GlHCP-EhHCP clade was close to Class I, including the TvHCP, and Classes II and III were closely related with each other. The finding of eukaryal HCPs would help to understand the evolutionary history of HCP.

• 생명과학회지
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• 제17권5호
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• pp.694-698
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• 2007

본 연구에서는 berberine이 세포성 면역에 미치는 효과를 보기위하여 림프구증식과 GM-CSF생성을 보고자 하였다. 마우스 비장세포에 berberine을 작용시켰을 때 저농도에서 세포성장을 촉진함으로서 림프구증식에 자극제로서의 역할을 담당할 것으로 보인다. GM-CSF의 생성은 berberine 단독처리에 의해서 증가됨으로서 GM-CSF생성의 증가로 인한 세포성 면역반응의 상승이 예상되고 LPS나 Con A에 의한 GM-CSF의 생성을 저해함으로서 과도한 GM-CSF생성을 중간에서 차단할 것으로 보인다. 따라서 이러한 결과들은 앞으로의 추가적인 연구결과들이 있게 되면 임상에서의 면역요법과 항염증작용에 berberine이 이용될 가능성을 시사한다 하겠다.

• 생태와환경
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• 제41권1호
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• pp.111-115
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• 2008

Direct effects of zooplankton grazing activities on the natural assemblage of bacterioplankton and algae were evaluated at monthly intervals, from June to October of 2000, in the middle part of the River Spree, Germany. We quantified bacterioplankton, algae, zooplankton abundance and measured carbon ingestion rates (CIRs) by zooplankton according to two zooplankton size classes: (i) micro zooplankton (MICZ), ranging in size from 30 to $150{\mu}m$ and including rotifers and nauplii, excluding protozoans and (ii) macrozooplankton (MACZ), larger than $150{\mu}m$ and including cladocerans and copepods. CIRs were measured using natural bacterial and algae communities in the zooplankton density manipulation experiments. Algae biomass (average${\pm}$SD: $377{\pm}306{\mu}gC\;L^{-1}$, n=5) was always higher than bacterial biomass ($36.7{\pm}9.9{\mu}gC\;L^{-1}$, n=5). Total zooplankton biomass varied from 19.8 to $137{\mu}gC\;L^{-1}$. Total mean biomass of zooplankton was $59.9{\pm}52.5{\mu}gC\;L^{-1}$ (average${\pm}$SD, n=5). Average MICZ biomass ($40.2{\pm}47.6{\mu}gC\;L^{-1}$ n=5) was nearly twofold higher than MACZ biomass ($19.6{\pm}20.6{\mu}gC\;L^{-1}$ n=5). Total zooplankton CIRs on algae (average${\pm}$SD: $56.6{\pm}26.4{\mu}gC\;L^{-1}\;day^{-1}$) were $\sim$fourfold higher than that on bacteria $(12.7{\pm}6.0{\mu}gC\;L^{-1}\;day^{-1})$. MICZ CIRs on bacteria $(7.0{\pm}2.8{\mu}gC\;L^{-1}\;day^{-1})$ and algae $(28.6{\pm}20.6{\mu}gC\;L^{-1}\;day^{-1})$ were slightly higher than MACZ CIRs. On average, MICZ accounted for 55.6 and 50.5% of total zooplankton grazing on bacteria and algae, respectively. Considering the MICZ and MACZ CIRs, the relative role of transferring carbon to higher trophic levels were nearly similar between both communities in the lake-river ecosystem.

• 한국패류학회지
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• 제26권3호
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• pp.211-215
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• 2010

퍼킨서스편모충 P. olseni는 우리나라 바지락의 대부분이 감염되어 있으며 극심한 염증을 유발하는 우리나라 바지락의 대표적 기생충이다. 본 연구에서는 퍼킨서스편모충의 생태학적 특성을 조사하고자 영양체에서 휴면포자로 전환되는 과정과 유주자를 형성하는 과정에서 수온과 염분이 미치는 영향을 조사하였다. 조사결과 영양체에서 휴면포자로의 유도는 수온이 높을수록 유도율이 높고 휴면포자의 직경이 커지는 현상이 관찰되었다. 또한 유주자 형성은 고수온, 고염분의 환경에서 잘 형성됨으로써 $10^{\circ}C$ 이하에서는 유주자 발생이 이루어지 않으며, 10 ppt에서는 유주자 형성이 급격히 감소하고 5 ppt에서는 유주자 발생이 이루어지지 않음이 확인되었다. 이러한 퍼킨서스편모충의 생태학적 정보는 이 질병의 구제 대책 수립에 중요한 정보를 제공할 수 있을 것으로 기대된다.

• BMB Reports
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• 제40권5호
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• pp.773-782
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• 2007

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 ${\mu}g/mL$ and 5 ${\mu}g/mL$, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.