• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.461-469
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• 2016

Giardia lamblia is a protozoan that causes diarrheal diseases in humans. Cytoskeletal structures of Giardia trophozoites must be finely reorganized during cell division. To identify Giardia proteins which interact with microtubules (MTs), Giardia lysates were incubated with in vitro-polymerized MTs and then precipitated by ultracentifugation. A hypothetical protein (GL50803_8405) was identified in the precipitated fraction with polymerized MTs and was named GlMBP1 (G. lamblia microtubule-binding protein 1). Interaction of GlMBP1 with MTs was confirmed by MT binding assays using recombinant GlMBP1 (rGlMBP1). In vivo expression of GlMBP1 was shown by a real-time PCR and western blot analysis using anti-rGlMBP1 antibodies. Transgenic G. lamblia trophozoites were constructed by integrating a chimeric gene encoding hemagglutinin (HA)-tagged GlMBP1 into a Giardia chromosome. Immunofluorescence assays of this transgenic G. lamblia, using anti-HA antibodies, revealed that GlMBP1 mainly localized at the basal bodies, axonemes, and median bodies of G. lamblia trophozoites. This result indicates that GlMBP1 is a component of the G. lamblia cytoskeleton.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.422-423
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• 2000

The protozoan parasite Giardia lamblia has been implicated as the causative agents of many outbreaks of waterborne intestinal illness. Accurate evaluation of Giardia lamblia removal in water treatment process requires a reliable method for measuring the concentrations of these pathogens in water. The relative recovery of Giardia cysts was assessed for seeded samples of distilled water. Cysts preparation was done by encystment in vitro. Membrane filtration was evaulated with cellulose acetate, polycarbonate, polypropylene, polyethersulfone, nylon membranes. Elution conditions were varied to improve cyst recovery.

• Parasites, Hosts and Diseases
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• 제58권6호
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• pp.675-679
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• 2020

MYB2 protein was identified as a transcription factor that showed encystation-induced expression in Giardia lamblia. Although nuclear import is essential for the functioning of a transcription factor, an evident nuclear localization signal (NLS) of G. lamblia MYB2 (GlMYB2) has not been defined. Based on putative GlMYB2 NLSs predicted by 2 programs, a series of plasmids expressing hemagglutinin (HA)-tagged GlMYB2 from the promoter of G. lamblia glutamate dehydrogenase were constructed and transfected into Giardia trophozoites. Immunofluorescence assays using anti-HA antibodies indicated that GlMYB2 amino acid sequence #507-#530 was required for the nuclear localization of GlMYB2, and this sequence was named as NLSGlMYB2. We further verified this finding by demonstrating the nuclear location of a protein obtained by the fusion of NLSGlMYB2 and G. lamblia glyceraldehyde 3-phosphate dehydrogenase, a non-nuclear protein. Our data on GlMYB2 will expand our understanding on NLSs functioning in G. lamblia.

• Parasites, Hosts and Diseases
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• 제57권2호
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• pp.185-189
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• 2019

To identify the component(s) involved in cell cycle control in the protozoan Giardia lamblia, cells arrested at the G1/S- or G2-phase by treatment with nocodazole and aphidicolin were prepared from the synchronized cell cultures. RNA-sequencing analysis of the 2 stages of Giardia cell cycle identified several cell cycle genes that were up-regulated at the G2-phase. Transcriptome analysis of cells in 2 distinct cell cycle stages of G. lamblia confirmed previously reported components of cell cycle (PcnA, cyclin B, and CDK) and identified additional cell cycle components (NEKs, Mad2, spindle pole protein, and CDC14A). This result indicates that the cell cycle machinery operates in this protozoan, one of the earliest diverging eukaryotic lineages.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.171-171
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• 2005

• 대한환경공학회지
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• 제29권8호
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• pp.904-908
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• 2007

병원성 원생동물인 지아디아 람블리아는 수인성 질병을 야기하는 주요 원인이 되고 있다. 본 연구는 PCR 및 RT-PCR 기법을 적용하여 한강본류 하천수 시료에서 사람감염성 종인 지아디아 람블리아를 동정하고, 활성 여부를 판별하여 현 표준시험방법을 보완하고자 하였다. PCR과 RT-PCR에는 지아디아의 복부 흡반 구성 유전자를 증폭하는 giardin primer를 사용하였으며, DNA/RNA 추출 및 PCR/RT-PCR 과정에서의 민감도 검사를 수행한 결과, 1포낭까지 검출가능한 것으로 나타났다. 또한 한강본류 및 유입지천 시료 48점에 적용하여 면역형광항체법과 PCR 및 RT-PCR 방법을 비교하였다. 면역형광항체법을 이용한 현미경관찰 결과 48개 시료의 지아디아 총포낭수의 평균 농도는 6.3 cysts/10 L이었고 양성율은 62.5%였으며, 속빈 포낭을 제외한 지아디아의 평균 농도는 4.5 cysts/10 L이었고 양성율은 52.1%였다. PCR 수행결과 48개 시료 중 24개(50%)의 시료에서 지아디아 람볼리아가 검출되었으며, RT-PCR 수행결과 10개(21%) 시료가 살아있는 G. lamblia를 포함한 것으로 나타났다. 본 연구를 통해 PCR/RT-PCR 기법이 지아디아 포낭을 저농도로 포함하고 있는 하천수 시료에 적용가능하며 원생동물 표준시험방법을 보완하여 종(species) 및 활성에 대한 정보를 제공할 수 있을 것으로 결과되었다.

• Parasites, Hosts and Diseases
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• 제47권3호
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• pp.287-291
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• 2009

The ${\alpha}/{\beta}$-tubulin heterodimer is the basic subunit of microtubules in eukaryotes. Polyclonal antibodies specific to recombinant ${\alpha}$-tubulin of Giardia lamblia were made, and found effective as a probe to specifically detect G. lamblia by immunofluorescence assays. Nucleotide sequences of ${\alpha}$-tubulin genes were compared between G. lamblia WB and GS strains, prototypes of assemblage A and assemblage B, respectively. A set of primers was designed and used to amplify a portion of the ${\alpha}$-tubulin gene from G. lamblia. PCR-RFLP analysis of this ${\alpha}$-tubulin PCR product successfully differentiated G. lamblia into 2 distinct groups, assemblages A and B.Theresults indicate that ${\alpha}$-tubulin can be used as a molecular probe to detect G.lamblia.

• Parasites, Hosts and Diseases
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• 제44권1호
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• pp.21-26
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• 2006

A shuttle vector for Escherichia coli and Giardia lamblia was modified to produce a reporter plasmid, which monitors the expression of prescribed gene in G. lamblia by measuring its luciferase activity. Promoter regions of the gap2 gene, one of the genes induced during encystation, were cloned into this plasmid, and the resultant constructs were then transfected into trophozoites of G. lamblia. Transgenic trophozoites containing one of the 3 gap2-luc reporters were induced to encystation, and characterized with respect to gap2 gene expression by measuring their luciferase activities. Giardia containing a gap2-luc fusion of 112-bp upstream region showed full induction of luciferase activity during encystation.

• Parasites, Hosts and Diseases
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• 제58권6호
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• pp.681-687
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• 2020

Giardia lamblia is a common enteric pathogen associated with diarrheal diseases. There are some reports of G. lamblia infection among different breeds of cattle in recent years worldwide. However, it is yet to know whether cattle in Jiangxi province, southeastern China is infected with G. lamblia. The objectives of the present study were to investigate the prevalence and examine the multilocus genotypes of G. lamblia in cattle in Jiangxi province. A total of 556 fecal samples were collected from 3 cattle breeds (dairy cattle, beef cattle, and buffalo) in Jiangxi province, and the prevalence and genotypes of G. lamblia were determined by the nested PCR amplification of the beta-giardin (bg) gene. A total of 52 samples (9.2%) were positive for G. lamblia. The highest prevalence of G. lamblia was detected in dairy cattle (20.0%), followed by that in beef cattle (6.4%), and meat buffalo (0.9%). Multilocus sequence typing of G. lamblia was performed based on sequences of the bg, triose phosphate isomerase and glutamate dehydrogenase loci, and 22, 42, and 52 samples were amplifiable, respectively, forming 15 MLGs. Moreover, one mixed G. lamblia infection (assemblages A and E) was found in the present study. Altogether, 6 novel assemblage E subtypes (E41*-E46*) were identified for the first time. These results not only provided baseline data for the control of G. lamblia infection in cattle in this southeastern province of China, but also enriched the molecular epidemiological data and genetic diversity of G. lamblia in cattle.

• Parasites, Hosts and Diseases
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• 제37권2호
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• pp.121-125
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• 1999

Inoculation of human fecal cysts to suckling Mongolian gerbils, two Giardia lamblia isolates, Kl and K2, were established as axenic cultures. Using this in vitro culture, both two Giardia isolates were grouped by using two genetic analysis. With genetic analysis of SSS-rDNA sequences, both K1 and K2 were found as members of hopkins'group 1, despite some nucleotide differences noticed in K1 (5 differences/292 bases.). The other genetic study used PCI-RFLP of the tim (triose phosphate isomerase) Nash's group 2 can bot be a separate group, but a part of Hopkins' group 1.