• 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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• 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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• 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.

• Parasites, Hosts and Diseases
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• 제57권3호
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• pp.225-232
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• 2019

Innate lymphoid cells (ILCs) are key players during an immune response at the mucosal surfaces, such as lung, skin, and gastrointestinal tract. Giardia lamblia is an extracellular protozoan pathogen that inhabits the human small intestine. In this study, ILCs prepared from the lamina propria of mouse small intestine were incubated with G. lamblia trophozoites. Transcriptional changes in G. lamblia-exposed ILCs resulted in identification of activation of several immune pathways. Secretion of interleukin (IL)-17A, IL-17F, $IL-1{\beta}$, and interferon-${\gamma}$ was increased, whereas levels of IL-13, IL-5, and IL-22, was maintained or reduced upon exposure to G. lamblia. Goup 3 ILC (ILC3) was found to be dominant amongst the ILCs, and increased significantly upon co-cultivation with G. lamblia trophozoites. Oral inoculation of G. lamblia trophozoites into mice resulted in their presence in the small intestine, of which, the highest number of parasites was detected at the 5 days-post infection. Increased ILC3 was observed amongst the ILC population at the 5 days-post infection. These findings indicate that ILC3 from the lamina propria secretes IL-17 in response to G. lamblia, leading to the intestinal pathology observed in giardiasis.

• 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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• 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.

• 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.

• 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.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.529-531
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• 2000

Giardia lamblia, a waterborne parasitic protozoa causing diarrhea and gastroenteritis, is transmitted to humans from untreated and treated water in the form of cysts. The ingestion of G. lamblia cysts is followed by the excystation of the cysts to trophozoites and subsequent colonization of the upper small intestine. In this study, the in vitro conditions for upper small intestine. In this study, the in vitro conditions for G. lamblia encystation were investigated to enhance the efficiency of cyst conversion and the resulting cyst density. The trophozoite of G. lamblia was cultivated to the late exponential growth phase, resulting in a high density of over $6{\times}10^7{\;}cells/ml$. The effects of pH, bile content, and induction time were evaluated; A cyst conversion of over 25% and 107 time were evaluated; A cyst conversion of over 25% and 107 cysts/ml were routinely obtained using the optimized encystation conditions including a slightly slkaline pH, 10 to 15 mg/ml of bile concentration, and 48-50 h of induction time.

• Parasites, Hosts and Diseases
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• 제54권5호
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• pp.631-636
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• 2016

This study aimed to develop a multiplex-touchdown PCR method to simultaneously detect 3 species of protozoan parasites, i.e., Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis, the major causes of traveler's diarrhea and are resistant to standard antimicrobial treatments. The target genes included the Cryptosporidium oocyst wall protein for C. parvum, Glutamate dehydrogenase for G. lamblia, and 18S ribosomal RNA (18S rRNA) for C. cayetanensis. The sizes of the amplified fragments were 555, 188, and 400 bps, respectively. The multiplex-touchdown PCR protocol using a primer mixture simultaneously detected protozoa in human stools, and the amplified gene was detected in > $1{\times}10^3$ oocysts for C. parvum, > $1{\times}10^4$ cysts for G. lamblia, and > 1 copy of the 18S rRNA gene for C. cayetanensis. Taken together, our protocol convincingly demonstrated the ability to simultaneously detect C. parvum, G. lamblia, and C. cayetanenesis in stool samples.