• BMB Reports
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• v.44 no.4
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• pp.285-290
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• 2011

Caenorhabditis elegans undergoes a developmental molting process that involves a coordinated interplay among diverse intracellular pathways. Here, we investigated the functions of two fatty acid biosynthesis genes; pod-2, encoding acetyl-CoA carboxylase, and fasn-1, encoding fatty acid synthase, in the C. elegans molting process. Although both the pod-2 and fasn-1 genes were expressed at constant levels throughout C. elegans development, knockdown of the proteins encoded by these genes using RNA interference produced severe defects in triglyceride production, molting, and reproduction that were coupled to suppression of NAS-37, a metalloprotease. An assessment of the structure and integrity of the cuticle using a COL-19::GFP marker and Hoechst 33258 staining showed that downregulation of either pod-2 or fasn-1 impaired cuticle formation and disrupted the integrity of the cuticle and the hypodermal membrane.

• Molecules and Cells
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• v.26 no.4
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• pp.344-349
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• 2008

5-Fluorouracil (5-FU), a pyrimidine antagonist, has a long history in cancer treatment. The targeted pyrimidine biosynthesis pathway includes dihydropyrimidine dehydrogenase (DPD), which converts 5-FU to an inactive metabolite, and thymidylate synthase (TS), which is a major target of 5-FU. Using Caenorhabditis elegans as a model system to study the functional and resistance mechanisms of anti-cancer drugs, we examined these two genes in order to determine the extent of molecular conservation between C. elegans and humans. Overexpression of the worm DPD and TS homologs (DPYD-1 and Y110A7A.4, respectively) suppressed germ cell death following 5-FU exposure. In addition, DPYD-1 depletion by RNAi resulted in 5-FU sensitivity, while treatment with Y110A7A.4 RNAi and 5-FU resulted in similar patterns of embryonic death. Thus, the pathway of 5-FU function appears to be highly conserved between C. elegans and humans at the molecular level.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.371-383
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• 2014

The nematode Caenorhabditis elegans (C. elegans) offers a unique opportunity for biological and basic medical researches due to its genetic tractability and well-defined developmental lineage. It also provides an exceptional model for genetic, molecular, and cellular analysis of human disease-related genes. Recently, C. elegans has been used as an ideal model for the identification and functional analysis of drugs (or small-molecules) in vivo. In this review, we describe conserved oncogenic signaling pathways (Wnt, Notch, and Ras) and their potential roles in the development of cancer stem cells. During C. elegans germline development, these signaling pathways regulate multiple cellular processes such as germline stem cell niche specification, germline stem cell maintenance, and germ cell fate specification. Therefore, the aberrant regulations of these signaling pathways can cause either loss of germline stem cells or overproliferation of a specific cell type, resulting in sterility. This sterility phenotype allows us to identify drugs that can modulate the oncogenic signaling pathways directly or indirectly through a high-throughput screening. Current in vivo or in vitro screening methods are largely focused on the specific core signaling components. However, this phenotype-based screening will identify drugs that possibly target upstream or downstream of core signaling pathways as well as exclude toxic effects. Although phenotype-based drug screening is ideal, the identification of drug targets is a major challenge. We here introduce a new technique, called Drug Affinity Responsive Target Stability (DARTS). This innovative method is able to identify the target of the identified drug. Importantly, signaling pathways and their regulators in C. elegans are highly conserved in most vertebrates, including humans. Therefore, C. elegans will provide a great opportunity to identify therapeutic drugs and their targets, as well as to understand mechanisms underlying the formation of cancer.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.84-92
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• 2019

Listeria monocytogenes is a major cause of serious foodborne illness in the dairy foods. Although Caenorhabditis elegans model is well established as a virulence model of pathogenic bacteria, its application on L. monocytogenes is critically unclear. The objective of this study was to carry out an evaluation of L. monocytogenes toxicity using C. elegans nematode as a simple host model. We found that C. elegans nematodes have high susceptibility to L. monocytogenes infection, as a consequence of accumulation of bacteria in the worms' intestine. However, L. innocua, which is known to be non-toxic, is not accumulate in the intestine of worms and is not toxic similarly to Escherichia coli OP50 known as the normal feed source of C. elegans. Importantly, immune-associated genes of C. elegans were intensely upregulated more than 3.0-fold when they exposed to L. monocytogenes. In conclusion, we established that C. elegans is an effective model for studying the toxicity of L. monocytogenes and we anticipate that this system will result in the discovery of many potential anti-listeria agents for dairy foods.

• Journal of the Korean Society of Visualization
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• v.12 no.2
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• pp.18-22
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• 2014

Caenorhabditis elegans (C. elegans) is an undulatory nematode which exhibits two distinct locomotion types of swimming and crawling. Although in its natural habitat C. elegans lives in a non-Newtonian fluidic environment, our current understanding has been limited to the behavior of C. elegans in a simple Newtonian fluid. Here, we present some experimental results on the penetrating behavior of C. elegans at the interface from liquid to solid environment. Once C. elegans, which otherwise swims freely in a liquid, makes a contact to the solid gel boundary, it begins to penetrate vertically to the surface by changing its stroke motion characterized by a stiffer body shape and a slow stroke frequency. The particle image velocimetry (PIV) analysis reveals the flow streamlines produced by the stroke of worm. For the worm that crawls on a solid surface, we utilize a technique of traction force microscopy (TFM) to find that the crawling nematode forms localized force islands along the body where makes direct contacts to the gel surface.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.903-909
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• 2021

Caenorhabditis elegans whose DNA sequence was completely identified is a representative species used in various research fields such as gene functional analysis and animal behavioral research. In the mean time, many researches on the bio-monitoring system to determine whether water is contaminated or not by using the swimming activities of nematodes. In this paper, we show the possibility of using the swimming activities of C. elegans in the development of a machine learning based bio-monitoring system which identifies chemicals that cause water pollution. To characterize swimming activities of nematode, BLS entropy is computed for the nematode in a frame. And, BLS entropy profile, an assembly of entropies, are classified into several patterns using clustering algorithms. Finally these patterns are used to construct data sets. We recorded images of swimming behavior of nematodes in the arenas in which formaldehyde, benzene and toluene were added at a concentration of 0.1 ppm, respectively, and evaluate the performance of the developed HMM.

• Korean Journal of Pharmacognosy
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• v.48 no.1
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• pp.63-69
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• 2017

Saururus chinensis (Lour.) Baill. (Saururaceae) has been used as a traditional medicine for the treatment of dysuria, leukorrhea, eczema, jaundice and ascites in Korea, China and Japan. Ethanol extract of S. chinensis was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction showed the most potent DPPH radical scavenging and superoxide quenching activities. To verify antioxidant activities of ethyl acetate fraction, we checked the activities of superoxide dismutase (SOD) and catalase, and intracellular ROS level and oxidative stress tolerance in Caenorhabditis elegans. Furthermore, to see if increased stress tolerance of worms by treating of ethyl acetate fraction was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain. Consequently, ethyl acetate fraction elevated SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, ethyl acetate fraction-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.

• 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.20 no.2
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• pp.80-85
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• 2014

In the course of screening for antioxidant compounds from natural plants in Korea by measuring the radical scavenging effect, a methanol extract of the flower buds of Daphne genkwa S. et Z. (Thymelaeaceae) was found to show a potent antioxidant activity. Subsequent activity-guided fractionation of methanol extract of D. genkwa led to the isolation of four compounds from the ethyl acetate soluble fraction. The chemical structures were elucidated as genkwanin (1), 3'-hydroxygenkwanin (2), apigenin (3), and tiliroside (4) by spectroscopic techniques. Among them, compound 2 showed the significant anti-oxidative effect on DPPH. And compound 2 showed the significant riboflavin-and xanthine-originated superoxide quenching activities. To verify the antioxidant enzymatic activities of compound 2, the SOD enzymatic activity was measured spectrophtometrically using prepared Caenorhabditis elegans homogenates. The results showed that compound 2 was able to elevate SOD activity of C. elegans in a dose dependent manner. Moreover, compound 2 decreased the intracellular ROS accumulation of worms.

• Korean Journal of Pharmacognosy
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• v.48 no.4
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• pp.314-319
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• 2017

To evaluate the longevity property of Allium hookeri (Liliaceae) leaves, this study was performed. Ethanol extract of A. hookeri was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions, and lifespan-extending effects of the fractions were checked using Caenorhabditis elegans model system. The most active ethyl acetate-soluble fraction elevated heat stress tolerance, and increased expression of stress resistance protein. Further studies were performed to investigate several aging-related factors such as reproduction, food intake, growth and movement of C. elegans. The results revealed that there were no significant changes in aging-related factors including reproduction and food intake, however, ethyl acetate-soluble fraction treatment led to up-regulation of locomotory ability and growth of aged worms, suggesting ethyl acetate-soluble fraction affected healthspan as well as lifespan of nematode.