• BMB Reports
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• 제37권1호
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• pp.107-113
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• 2004

Since the completion of the genome project of the nematode C. elegans in 1998, functional genomic approaches have been applied to elucidate the gene and protein networks in this model organism. The recent completion of the whole genome of C. briggsae, a close sister species of C. elegans, now makes it possible to employ the comparative genomic approaches for identifying regulatory mechanisms that are conserved in these species and to make more precise annotation of the predicted genes. RNA interference (RNAi) screenings in C. elegans have been performed to screen the whole genome for the genes whose mutations give rise to specific phenotypes of interest. RNAi screens can also be used to identify genes that act genetically together with a gene of interest. Microarray experiments have been very useful in identifying genes that exhibit co-regulated expression profiles in given genetic or environmental conditions. Proteomic approaches also can be applied to the nematode, just as in other species whose genomes are known. With all these functional genomic tools, genetics will still remain an important tool for gene function studies in the post genome era. New breakthroughs in C. elegans biology, such as establishing a feasible gene knockout method, immortalized cell lines, or identifying viruses that can be used as vectors for introducing exogenous gene constructs into the worms, will augment the usage of this small organism for genome-wide biology.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.30-36
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• 1984

An ultrastructural study on the mature spermatoBoa oi Cloptorchis sineitsis was carried out. For this study, the liver cukes were collected from the livers of rabbits and rats artificially infected with the metacercariae obtained from the fresh water fish, Pseudorasbora parve. Six-month old worms were used. The collected liver fiukes were washed with 0.85% saline solution and then immediately moved to cold 2% glutaraldehyde buffered with 0.1M Millonig's phosphate buffier (pH 7.4) . The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials containing the seminal receptacle were rinsed several times with the buffier and were secondarily fixed with cold, bugeyed 1% osmium tetroxide(OsO4) for 2 hours. The fully mixed tissue blocks Ivere dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from LKB-5 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with JEM-100CX II electron microscope, In general, the mature sperm was long thread-like form with a sickle-shaped head. According to the longitudinal sectioned view of the sperm tail, the nucleus seemed to be spirally coiled and run a little far along the tail. The acrosome was not observed. The cytoplasm of the tail was biflagellated as usual in trematodes. Unlike other platyhelminth spermatozoa, the sperm tail of Clenorchis sinensis showed the ${\ulcorner}9+2{\lrcorner}$ in the microtubular arrangement. The mitochondria with poorly developed cristae were observed throughout the middle piece. The middle piece of the tail showed dull ladder or triangular shapes with the two flagella at the bottom. But, the principal piece of the tail was slightly flattened cylindrical shape with two aagella within the cytoplasm. The end piece was uniflagellated. It was not clearly identised whether the end piece was subdivided into two by aagellum or the lengths of the two aagella were different. The glycogen granules were rich in the cytoplasm throughout the lenght of the spermatozoa. These granules might be the energy source for the movement of the spermatosoa.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.43-50
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• 1984

Two cases of human infection by Stellantchasmus falcatus (Heterophyidae) were identified by collection of adult worms during the treatment of some tapeworm infections in Korea. The cases were 24 (Case 1) and 55-year old (Case 2) males residing in Seoul. The Case 1 had gastrointestinal troubles such as diarrhea and abdominal pain, and heart problems such as palpitation and arrhythmia, revealing the eggs of Diphyllobothrium latum in the feces. The Case 2 complained indigestion and discharge of tapeworm (Taenia saginata) segments. Praziquantel at the dose of 15-20mg/kg body weight and 30 g magnesium salt were given to them for treatment of the tapeworm infections and the discharged strobilae were identified. However, concommitantly with the tapeworms, 188 and 5 specimens of S. falcatus were collected from Case 1 and Case 2 respectively through stereomicroscopy of the diarrheal stools. The Case 1 was infected also with 3 other kinds of heterophyid flukes. They said to have eaten raw brackish water fish such as mullets which are considered to be the source of heterophyid fluke infections.

• Biomolecules & Therapeutics
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• 제23권6호
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• pp.582-589
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• 2015

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.

• Korean Journal of Pharmacognosy
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• 제48권1호
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• pp.25-30
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• 2017

This study was performed to evaluate the lifespan extending effects of the dried ginger (Zingiber officnale Roscoe, Zingiberaceae). Ethanol extract of the dried ginger was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions, and lifespan-extending effects of the fractions were investigated using Caenorhabditis elegans model system. Ethyl acetate-soluble fraction showed the most potent longevity property. Furthermore, ethyl acetate-soluble fraction elevated thermal 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, food intake and growth, however, ethyl acetate-soluble fraction treatment led to an up-regulation of locomotory ability of aged worms, suggesting ethyl acetate-soluble fraction affected healthspan as well as lifespan of nematode.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제5권4호
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• pp.346-356
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• 2000

This study was carried out to investigate the distribution pattern of macrobenthos in the subtidal sandy bottoms of the east coast of Korea, and seasonal samplings were performed from April 1993 to February 1994. The species number of macrobenthos was in the range from 70 in winter to 109 in spring season. Polychaete worms were the most dominant faunal group in species richness and abundance, but mollusks showed the highest biomass. The mean density of macrobenthos fluctuated from 631 individuals/m$^2$ in autumn to 1,995 individuals/m$^2$ in summer. The major macrofauna in abundance were polychaetes, Spiophanes bombyx which occurred all seasons with top rank and Prionospio sp. and a mollusk, Alvenius ojianus, and crustaceans, Wecomedon sp. and Urothoidae spp. were also numerically dominant macrobenthic fauna. The macrobenthos in the study area were classified into two assemblages by water depth. However, they showed a different community structure near small rivers in autumn and winter seasons.

• The Korean Journal of Soil Zoology
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• 제5권2호
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• pp.63-70
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• 2000

The effect of combinations of temperature, water column height and extraction time onthe efficiency of wet funnel extraction methods for enumerating Enchytraeids in a blanket bog peat soil from Moor House, Cumbria, England were investigated. The optimal conditions for extracting enchytraeids from this study were found to be a water surface temperature of 35$^{\circ}C$, with an extraction time of 6 hours, regardless of initial water temperature and water level in the extraction funnel. The original O'Connor method (40-45$^{\circ}C$ for 3 hours extraction and gradually increasing heating) yielding a high variation in the extraction efficiency, largely due to the comparatively higher temperature and shorter extraction time than this method. Attempts to extract without heat over longer periods showed very low extraction efficiencies for this highly organic blanket bog soil when compared with any of the heating wet funnel methods.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.37-42
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• 1984

Two human cases of Heterophyes heterophyes nocens infection were proved by identifying adult worms after treatment with bithionol or praziquantel in 1983 in Korea. They are 37 (Case 1) and 24-year old (Case 2) males whose resi¬dence or native village is a southern coastal area in Kohiing-gun, Chollanam-do. The Case 1 had the gastrointestinal symptoms such as epigastric pain and indigestion, and the Case 2 heart problems such as arrhythmia and ventricular premature beat in EKG and digestive symptoms such as diarrhea and abdominal pain. After the treatments, 35 and 67 specimens of H. hetero¬phyes nocens respectively were collected from the diarrheal stools through stereomicroscopy. The Case 1 was concommitantly infected with Clonorchis sinensis and the Case 2 with 3 other kinds of heterophyid flukes and with Diphyllo¬bothrium latum. The cases said to have eaten raw brackish water fish such as mullets (Mugil cephalus), perches (Lateolabrax japonicus) and gobies (Acanthogobius flavimanus) which are the intermediate hosts of H. heterophyes nocens in Korea.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.61-65
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• 1984

A mass fecal examination was performed in Seoul, Korea from December 1983 to March 1984 and 15 egg positive cases of Fibricola seoulensis were discovered. They were treated with praziquantel($Distocide{\circledR}$) 20mg/kg single dose and magnesium salt for purgation. The adult worms of F. seoulensis were collected from 6 of them. The number of the flukes ranged 1-78 by the case. The cases had no clinical manifestation at all. They were all Korean males in twenties, and had the histories of eating the roast or raw snakes or frogs. Fibricoliasis is expected to be prevalent among the snake-eaters in Korea. Further cases will be detected by sedulous differentiation of thinshelled immature operculated eggs of 0.08~0.102mmn length. Praziquantel seems to be an excellent chemotherapeutic for fibricoliasis.

• Journal of fish pathology
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• 제33권1호
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• pp.15-21
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• 2020

We found skin flukes in snubnose pompano (Trachinotus blochii) from a public aquarium and attempted clear identification of them to the species level by morphology and molecular analyses. Skin flukes were collected from snubnose pompano showing dyspnea, anorexia and mild hemorrhage on the skin. All the fish samples (n=2) were infected with the flukes on the skin, gill and eyes, covered with excessive mucus. The isolated worms were transferred for making slide specimen and PCR amplification targeting 18S rDNA, 28S rDNA, mitochondrial cytochrome c oxidase subunit 1 (mt cox1) and cytochrome b (Cytb) genes for further analyses. Morphology and measurements data of our slide specimen coincided with those of Neobenedenia girellae. The sequence data of 2 genes (28S rDNA and Cytb) and the phylogenetic trees revealed that our specimen consistently belonged to the N. girellae clade. For 18S rDNA and mt cox1 genes, there was no sequence of either of these 2 Neobenedenia species from the type host available in GenBank. This is the first record of N. girellae in snubnose pompano, but it is still unclear if the snubnose pompano is a natural host for N. girellae or not because N. girellae is known to have an unusual broad host range and the host-switching can occur particularly in captive conditions such as aquarium or aquaculture facilities.