• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.105-106
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• 2008

As a carrier of malaria and sneak of blood, mosquitoes are an unpleasant insect. However, there are several unknown natural secretes related with mosquitoes. Among them, we focused on the blood sucking process of a female mosquito. The main objective of this study is to understand the mosquito's blood sucking mechanism that can be used to resolve the problem encountered in the injection or transport of infinitesimal biological fluids in a micro-chip. At first, the velocity fields of blood-sucking flow in a proboscis were measured using a micro-particle image velocimetry (PIV) technique. The velocity signals of flow in the proboscis show periodic variation. This seems to be resulted from the beating of the pharyngeal pump which works as driving power. To analyze the pumping mechanism, the temporal variation of the pharyngeal pump was visualized using the synchrotron X-ray micro-imaging technique. The volume variation was estimated by the help of digital image processing techniques. Once the main mechanism of blood sucking process was found, a effective micro-pumping system with high efficiency would be developed in near future.

• Molecules and Cells
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• v.25 no.1
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• pp.50-54
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• 2008

The vesicular glutamate transporter (VGLUT) transports glutamate into pre-synaptic vesicles. Three isoforms of VGLUT have been identified in humans, but their functional differences remain largely unknown. EAT-4 is the only homologue of human VGLUT in C. elegans. Here we report that mutants of eat-4 exhibit hyperforaging behavior and that each of the isoforms of human VGLUT functionally rescues the defects in eat-4 worms.

• Molecules and Cells
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• v.28 no.3
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• pp.209-213
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• 2009

Caenorhabditis elegans is a free living soil nematode and thus in its natural habitat, C. elegans encounters many different species of soil bacteria. Although some soil bacteria may be excellent sources of nutrition for the worm, others may be pathogenic. Thus, we undertook a study to understand how C. elegans can identify their preferred food using a simple behavioral assay. We found that there are various species of soil bacteria that C. elegans prefers in comparison to the standard laboratory E. coli strain OP50. In particular, two bacterial strains, Bacillus mycoides and Bacillus soli, were preferred strains. Interestingly, the sole feeding of these bacteria to wild type animals results in extended lifespan through the activation of the autophagic process. Further studies will be required to understand the precise mechanism controlling the behavior of identification and selection of food in C. elegans.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1026-1035
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• 2011

Vibrio parahaemolyticus, which owes its origin to the marine environment, is considered as one of the most common causes of infectious diarrhea worldwide. The present study investigated the pathogenicity of V. parahaemolyticus against the model organism, Caenorhabditis elegans. Infection in the host was localized with GFP-tagged V. parahaemolyticus using confocal laser scanning microscopy. The times required for causing infection, bacterial load in intestine, chemotactic response, and alteration in pharyngeal pumping were analyzed in the host system. In addition, the regulation of innate immune-related genes, lys-7, clec- 60, and clec-87, was analyzed using real-time PCR. The role of immune-responsible pmk-1 was studied using mutant strains. The pathogenicity of environmental strain CM2 isolated from the Gulf of Mannar, India was compared with that of a reference strain obtained from ATCC. The pathogen infected animals appeared to ward off infection by up-regulating candidate antimicrobial genes for a few hours after the exposure, before succumbing to the pathogen. For the first time, the pathogenicity of V. parahaemolyticus at both the physiological and molecular levels has been studied in detail using the model organism C. elegans.

• Natural Product Sciences
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• v.21 no.2
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• pp.128-133
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• 2015

Lindera obtusiloba has been widely used as a traditional medicine for the treatment of lots of diseases, including abdominal pain, bruise, and hepatocirrhosis. Here in this study, we elucidated the lifespan-extending effect of methanolic extract of Lindera obtusiloba (MLO) using Caenorhabditis elegans model system. We found that MLO has potent lifespan extension activities under normal culture condition. Then, we determined the protective effects of MLO on the stress conditions such as osmotic, thermal and oxidative stress. To reveal possible mechanism of MLO-mediated lifespan, we further investigated the effect of MLO on the antioxidant enzyme activities and intracellular ROS levels. Our results demonstrated that superoxide dismutase and catalase activities were significantly up-regulated by MLO treatment, resulted in reduced intracellular ROS levels. In this work, we also tested whether MLO-mediated longevity activity was associated with aging-related factors such as food intake and growth. Our data revealed that both of pharyngeal pumping rate and body length were significantly shifted by MLO treatment, indicating these factors were involved in MLO's lifespan-extension effects. Although MLO induces reduction in food intake, the body movement of MLO-fed aged worms was not decreased, compared to untreated control worms, indicating MLO might extend lifespan without affecting healthspan.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.38-43
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• 2015

Ligularia stenocephala has a wide range of types of constituents with various pharmacological properties. Here in this study, we examined the effect of methanolic extract of L. stenocephala (MLS) on the lifespan and stress tolerance using Caenorhabditis elegans model system. We found that lifespan of wild-type worms was significantly lengthened in the presence of MLS in a dose dependent manner. MLS also elevated the tolerance of worms against osmotic, heat shock, and oxidative stress. We also demonstrated in vivo antioxidant capacity of MLS by checking intracellular reactive oxygen species levels as well as antioxidant enzyme activities such as catalase and superoxide dismutase. We further investigated several aging-related factors, including pharyngeal pumping rate and body length. Here, we showed that MLS exerts longevity effect independent of both factors. In addition, body movement of aged worms was significantly elevated, suggesting MLS could enhance healthspan as well as lifespan.

• BMB Reports
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• v.56 no.12
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• pp.657-662
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• 2023

Neurodegenerative diseases are characterized by distinct protein aggregates, such as those of α-synuclein and tau. Lysosomal defect is a key contributor to the accumulation and propagation of aberrant protein aggregates in these diseases. The discoveries of common proteinopathies in multiple forms of lysosomal storage diseases (LSDs) and the identification of some LSD genes as susceptible genes for those proteinopathies suggest causative links between LSDs and the proteinopathies. The present study hypothesized that defects in lysosomal genes will differentially affect the propagation of α-synuclein and tau proteins, thereby determining the progression of a specific proteinopathy. We established an imaging-based high-contents screening (HCS) system in Caenorhabditis elegans (C. elegans) model, by which the propagation of α-synuclein or tau is measured by fluorescence intensity. Using this system, we performed RNA interference (RNAi) screening to induce a wide range of lysosomal malfunction through knock down of 79 LSD genes, and to obtain the candidate genes with significant change in protein propagation. While some LSD genes commonly affected both α-synuclein and tau propagation, our study identified the distinct sets of LSD genes that differentially regulate the propagation of either α-synuclein or tau. The specificity and efficacy of these LSD genes were retained in the disease-related phenotypes, such as pharyngeal pumping behavior and life span. This study suggests that distinct lysosomal genes differentially regulate the propagation of α-synuclein and tau, and offer a steppingstone to understanding disease specificity.