• 대한환경공학회지
• /
• 제28권8호
• /
• pp.843-851
• /
• 2006

년도별 검출결과 2001년도에 각 지점별로 많은 검출을 보였지만 2004년도로 갈수록 Cryptosporidium과 Giardia 모두 10(oo)cysts/20 L 이하의 낮은 검출을 보였으며, 계절별로는 여름철과 늦여름($6{\sim}9$월)이 가장 많이 검출되었으며 지점별로는 고령교가 가장 높게 검출되었다. Cryptosporidium과 수질지표분석항목은 낮은 상관성을 보였으나 탁도와의 상관성에서는 Cryptosporidium의 경우 $R^2$=0.4914, Giardia는 $R^2$=0.6176으로 높게 나타났으며 Cryptosporidium보다 Giardia가 더 높은 상관성을 보였다. 그리고 탁도가 20 NTU 이상 일 때 Cryptosporidium과 Giardia의 검출이 대체로 20(oo)cystsd/20L 이상 높게 나타남을 알 수 있었다. Cryptosporidium과 Giardia의 상관성은 $R^2$=0.8432로 높게 나타났다. 각 지점별로 Cryptosporidium과 Giardia는 동시에 검출되고 있었으며, Giardia의 농도가 대체로 높게 나타났다. 축산폐수나 하수의 영향이 큰 것으로 나타났다.

• 한국임상수의학회지
• /
• 제22권3호
• /
• pp.239-243
• /
• 2005

Current treatments for canine Giardia infections include albendazole, fenbendazole and metronidazole in the most cases. To compare efficacy of these antimicrobial drugs for treating naturally infected giardiasis in dogs, we used the zinc sulfate concentration technique(ZSCT) to figure out naturally infected with Giardia. In this study, feces were collected from 150 asymptomatic dogs at a kennel, 28 asymptomatic Giardia infected dogs were used by the allocated four group to receive albendazole(group A, 25 mg/kg, PO, bid, 7 days), fenbendazole(group F, 50 mg/kg, PO, sid, 7 days), metronidazole (group M, 50 mg/kg, PO, sid, 7 days), nontreated control(group NC) respectively. Fecal samples from each dog were examined for Giardia cysts within 3 days of the last treatment. Giardia cysts were not detected in the feces of any dog in group F. Cysts were detected in the feces 1 of 7 dogs in group A or in the feces 2 of 7 dogs in group M. In the group NC, cysts were detected in the feces of 7 of 7 dogs. Finally, there was significant difference for efficacy between antimicrobial drugs against Giardia in dogs. Fenbendazo1e is the most efficacy to have giardiacidal activity.

• Parasites, Hosts and Diseases
• /
• 제54권4호
• /
• pp.461-469
• /
• 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
• /
• 제60권3호
• /
• pp.163-172
• /
• 2022

Kinesin-13 (Kin-13), a depolymerizer of microtubule (MT), has been known to affect the length of Giardia. Giardia Kin-13 (GlKin-13) was localized to axoneme, flagellar tips, and centrosomes, where phosphorylated forms of Giardia polo-like kinase (GlPLK) were distributed. We observed the interaction between GlKin-13 and GlPLK via co-immunoprecipitation using transgenic Giardia cells expressing Myc-tagged GlKin-13, hemagglutinin-tagged GlPLK, and in vitro-synthesized GlKin-13 and GlPLK proteins. In vitro-synthesized GlPLK was demonstrated to auto-phosphorylate and phosphorylate GlKin-13 upon incubation with [γ-³²P]ATP. Morpholino-mediated depletion of both GlKin-13 and GlPLK caused an extension of flagella and a decreased volume of median bodies in Giardia trophozoites. Our results suggest that GlPLK plays a pertinent role in formation of flagella and median bodies by modulating MT depolymerizing activity of GlKin-13.

• Parasites, Hosts and Diseases
• /
• 제56권1호
• /
• pp.1-9
• /
• 2018

Giardia lamblia, an anaerobic, amitochondriate protozoan parasite causes parasitic infection giardiasis in children and young adults. It produces pyruvate, a major metabolic product for its fermentative metabolism. The current study was undertaken to explore the effects of pyruvate as a physiological antioxidant during oxidative stress in Giardia by cysteine-ascorbate deprivation and further investigation upon the hypothesis that oxidative stress due to metabolism was the reason behind the cytotoxicity. We have estimated intracellular reactive oxygen species generation due to cysteine-ascorbate deprivation in Giardia. In the present study, we have examined the effects of extracellular addition of pyruvate, during oxidative stress generated from cysteine-ascorbate deprivation in culture media on DNA damage in Giardia. The intracellular pyruvate concentrations at several time points were measured in the trophozoites during stress. Trophozoites viability under cysteine-ascorbate deprived (CAD) medium in presence and absence of extracellular pyruvate has also been measured. The exogenous addition of a physiologically relevant concentration of pyruvate to trophozoites suspension was shown to attenuate the rate of ROS generation. We have demonstrated that Giardia protects itself from destructive consequences of ROS by maintaining the intracellular pyruvate concentration. Pyruvate recovers Giardia trophozoites from oxidative stress by decreasing the number of DNA breaks that might favor DNA repair.

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

• 대한수의학회지
• /
• 제63권4호
• /
• pp.31.1-31.4
• /
• 2023

From 2008 to 2017, blood samples from 280 and fecal samples from 149 stray cats in Gwangju, South Korea, were examined for feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), Dirofilaria immitis, and Giardia infections using commercial diagnostic tests. Overall, the combined prevalence of FeLV, FIV, D. immitis, and Giardia was 8.6%, 1.4%, 0.4%, and 2.0%, respectively. FeLV exhibited the highest prevalence rate among the 4 pathogens surveyed, both in the 2008-2009 (9.6%) and 2015-2017 (6.3%) surveys. The results of the feline Giardia study represent the first prevalence report of Giardia infection among stray cats in Korea.

• Parasites, Hosts and Diseases
• /
• 제55권2호
• /
• pp.129-135
• /
• 2017

A total of 60 samples were collected from 35 swimming pools in Beijing, China, and the presence of Cryptosporidium and Giardia were investigated. The results showed that 16.7% and 15.0% of samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively, with a mean concentration of 0.30 oocysts/10 L and 0.27 cysts/10 L. The oocysts and cysts were found to have higher rates of occurrence in August than in May. Genotyping confirmed the presence of Cryptosporidium hominis, C. parvum, and Giardia assemblages A and B, all of which were associated with human infections. The predominant species/assemblages were C. hominis and Giardia assemblage A. Analyses of the relationships between parasite oocysts/cysts, indicator bacteria, and physical-chemical parameters revealed that there was no correlation between 2 parasites and fecal bacterial indicators, whilst there was a significant correlation between protozoa and urea concentration, which indicates that urea concentration rather than fecal bacterial indicators might be an appropriate index for chlorine-resistant protozoa in swimming pools. This study provides useful information to improve the safety of swimming pool water and deduce the risk of protozoan infections.

• Parasites, Hosts and Diseases
• /
• 제63권3호
• /
• pp.264-271
• /
• 2025

Posttranslational modification by the small ubiquitin-related modifier (SUMO) is one of the crucial cellular processes in Giardia lamblia, a protozoan pathogen. In this study, 5 candidate SUMO substrate proteins of G. lamblia trophozoites were chosen based on their enrichment through affinity chromatography using a SUMO-interaction motif: never in mitosis A-related kinase (NEK), aminoacyl-histidine dipeptidase (AHD), protein disulfide isomerase 2 (PDI2), alcohol dehydrogenase 3, and ornithine carbamoyltransferase. Transgenic Giardia trophozoites expressing 1 of the 5 candidate SUMO substrate proteins were constructed, and their expression was confirmed by western blot using hemagglutinin-tag. Arginine deiminase (ADI) protein was expressed in Giardia trophozoites as a positive control. Cell extracts were processed for affinity chromatography using SUMO-interaction motif resin. As expected, the SUMOylated form of ADI was detected in the affinity chromatography extracts of ADI-expressing cells. Among the 5 candidate proteins, SUMOylated forms of NEK, AHD, and PDI2 were identified in the affinity chromatography extracts. These results suggest that NEK, AHD, and PDI2 activity is modulated via SUMOylation in Giardia trophozoites.

• Parasites, Hosts and Diseases
• /
• 제63권1호
• /
• pp.12-24
• /
• 2025

Intraflagellar transport (IFT) particles, a multi-protein apparatus composed of complex A and B, are known to be involved in homeostasis of flagella formation. IFT particles have recently become an interesting topic in Giardia lamblia, which has 4 pairs of flagella. In this experiment, we examined the function of giardial IFT components. When 7 components (IFT121, 140, 20, 46, 52, 81, and 88) of IFT were expressed in Giardia trophozoites as a tagged form with mNeonGreen, all of them were found in both flagella pores and cytoplasmic axonemes. In addition, motor proteins for IFT particles (kinesin-13 and kinesin-2b), were localized to a median body and cytoplasmic flagella, respectively. The CRISPRi-mediated knockdown of IFT88 significantly affected the lengths of all 4 flagella compared to the control cells, Giardia expressing dead Cas9 using control guide RNA. Decreased expression of kinesin-2b also resulted in shortening of flagella, excluding the ventral flagella. Live Giardia cells expressing IFT88-mNeonGreen clearly demonstrated fluorescence in flagella pores and cytoplasmic axonemes. These results on IFT88 and kinesin-2b indicate that IFT complex plays a role in maintenance of G. lamblia flagella.