• YAKHAK HOEJI
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• v.51 no.3
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• pp.219-227
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• 2007

Ginsenoside Rgl (Rgl), the pharmacologically active constituent of ginseng (Panax ginseng C.A. Meyer), has a variety of biological activities. The present study was undertaken to evaluate a possibility of Rgl whether it can be used in treatment or prevention of stress disorders. Animals were stressed by immobilization for 2 hours or electroshocks for 20 minutes. The normal group was not exposed to any stress. Rgl was subcutaneously injected as dosages of 5 and 10 mg/kg and red ginseng (RG) was orally administered 200 mg/kg as the positive control. Animals were given supplements for 5 days without stress, and then were given supplements for 5 days with stress. We recorded stress-related behavioral changes of experimental animals using the Etho-vision system. Weight of adrenal gland and levels of corticosterone in plasma were measured and stress related behaviors (smelling, grooming, face washing, rearing) were observed. Rgl didn't make significant behavioral changes in total open field and elevated plus maze test. Rgl did not influence on behavioral changes induced by electroshock stress. Whereas, 10 mg/kg of Rgl alleviated the increment of the freezing and face washing time and the decrement of the smelling and rearing time induced by restraint stress. The administration of Rgl 10 mg/kg has significantly increased the endurance time on rotating rod and swimming pool tests compared to the control group. These results indicate that Rgl can alleviate the damage induced by physical stress. This result suggests that Rgl may bea new candidate for treating stress related disorder.

• International Journal of Stem Cells
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• v.9 no.2
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• pp.186-191
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• 2016

Background and Objectives: With the global demand for dairy protein for consumption growing annually, there has been increasing activity in the research field of dairy protein synthesis and production. From a manipulation perspective, it is more difficult to use live cattle for laboratory studies on the production of milk as well as of dairy protein such as casein, as compared with using laboratory animals like rodents. Therefore, we aimed to develop a mouse model of bovine mammary alveolar ducts for laboratory-scale studies. We studied the formation of the bovine mammary gland ductal structure by transplanting the MAC-T bovine alveolar cell line into mice. Methods and Results: MAC-T cells ($1{\times}10^7$) were suspended in Matrigel and injected into the dorsal tissue of 8-week-old male BALB/C nude mice. Histological analysis of tissue dissected from the MAC-T cell-transplanted mice after 6 weeks showed the typical morphology of the tubuloalveolar female gland, as well as glands made up of branching ducts that were surrounded by smooth muscle with small alveoli budding off the ducts. In addition, the epithelial markers CK14 and CK18 were expressed within the duct-like structure. Prolactin was detected in the duct interior in these CK14+ and CK18+ cells but not in the non-transplanted MAC-T cells. Conclusions: These results showed that duct-like tissue had been successfully formed after 6 weeks of transplantation of the CK14+ and CK18+ MAC-T cells into mice dorsal tissue. This mouse model will be a useful tool for further research on the bovine mammary gland.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.311-314
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• 2009

A total of 1,498 small mammals (rodents and insectivores), including Apodemus agrarius (n= 1,366), Crocidura lasiura (54), Mus musculus (32), Micronytus fortis (28), Eothenomys regulus (9), Micronys minutes (6), and Cricetulus triton (3), were live-trapped in Gyeonggi-do (Province) (Paju-si, Pocheon-gun, and Yeoncheon-gun) near the demilitarized zone (DMZ) from December 2004 to September 2005. A. agrarius was found to be infected with 3 species of echinostomes (Echinostoma hortense, Echinostoma cinetorchis, and Euparyphium murinum), while C. lasiura was infected with 1 species (Echinochasmus japonicas) of echinostome. Other mammals were free from echinostome infections. Total 16 E. hortense were detected in 7 (0.5%) mice, 9 E. cinetorchis from 5 (0.4%), and 3 E. murinum from 2 (0.1%) out of 1.366 A. agrarius examined. E. japonicus was found only in 1 (1.9%; total 3 specimens) C. lasiura. These results demonstrate that A. agrarius and C. lasiura, inhabiting near the DMZ of Gyeonggi-do serve as the natural definitive hosts for several species of echinostomes, although their infection rates are low. This is the first record of natural infections of A. agrarius with E. cinetorchis and C. lasiura with E. japonicus in the Republic of Korea.

• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.27-36
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• 1995

Comparative epidemiological studies on vector reservoir animals of tsutsugamushi disease were carried out in between south coast (the highest endemic) areas and east coast flow endemicl areas in October 1993. Fauna of field rodents and their population densities were not different between two areas. Antibody positive rate of Apodemus agrarius sera was higher in east coast (43.2% in south coast and 63.6% in east coast). High correlation (r = 0.87) was shown between antibody positive rate of A. osrwiur sera and population density of the vector mites (Leptotrombidium scutellare and 1. pnllidunl). L. scutellare was predominant in south coast, showing 110.6 chigger index (74.9% of the total chiggersl , whereas L. pcllidum was predominant in east coast, showing 126.3 chigger index (60.4% of the total). As higher population density of 1. scutellare was found in south coast where the prevalence rate of tsutsugamushi disease is the highest, it is believed that L. scutellare is more important vector species than L. pallidum which may result from more frequent vector-human contact.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.59-65
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• 2024

This study examined the fecal samples of striped field mice (Apodemus agrarius coreae) captured in Jeju Special Self-Governing Province. Fecal samples, including the colon and other intestinal organs, were collected and subjected to aerobic culture to investigate the distribution of intestinal microorganisms. Gram staining of the aerobic cultured bacterial colonies from 36 fecal samples revealed the predominant presence of gram-negative bacilli in all samples. Among the 36 samples, gram-negative bacilli were identified in 36 strains (100%), gram-positive cocci in 21 strains (58.3%), and gram-positive bacilli in 15 strains (41.7%), while no gram-negative cocci were observed. The gram-negative bacilli cultured from the 36 samples were identified using the Vitek 2 system, and all were determined to be Escherichia coli (E. coli) strains. In addition, one sample was concurrently identified with E. coli and Enterobacter cloacae strains. The antimicrobial susceptibility testing for the identified E. coli strains did not include all antibiotics, but one strain exhibited intermediate resistance to cefoxitin. No pathogenic bacteria were present in the fecal samples of the scrub typhus-infected rodents, which are vectors for chigger-borne diseases affecting humans and animals.

• Development and Reproduction
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• v.11 no.1
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• pp.13-20
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• 2007

In all female mammals, reproductive system is one of the first biological systems to show age-related decline. Female mammals in reproductive aging, though the phenomena is somewhat species-specific, start to show declining fertility and changes of numerous physiological functions. This review will present a current information on the aging of the female reproductive hormonal axis and introduce three useful rodent models for studying this field. Middle age($8{\sim}12$ months old) in female rats and mice is comparable to the stage prior to the entry of menopause in human. In this period pulsatile and surge GnRH secretion from hypothalamus gradually attenuated, then reduced pulsatile and surge LH secretion is followed consequently. This age-related defects in GnRH-LH neuroendocrine axis seem to be highly correlated with the defects in brain signals which modulate the activities of GnRH neuron. Many researchers support the idea which the age-related hypothalamic defects are the main cause of reproductive aging, but some ovarian factors such as inhibin response also could contribute to the induction of reproductive senescence. Some rodent models are quite valuable in studying the reproductive aging. The follitropin receptor knockout(FORKO) mice, both of null and haploinsufficient state, could produce depletion of oocyte/follicle with age. Dioxin/aryl hydrocarbon receptor(AhR) knockout mice also show severe ovarian defects and poor reproductive success early in their life compared to the age-matched normal mice. Further studies on the reproductive aging will be a great help to evaluate the benefits and risks of hormone replacement therapy(HRT) and to improve the safety of HRT.

• Parasites, Hosts and Diseases
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• v.30 no.4
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• pp.341-348
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• 1992

Because no reference on trombiculid mites (Acarina: Trombiculidae) in Cheju Island where tsutsugamushi disease is highly endemic had been available, studies on trombiculid mites in Cheju Island were implemented during the period of August 1991-Apil 1992, and the results obtained are summarized as follows: (1) The species and numbers of the field rodents collected were 143 Apodemus agrarius chejuensis (92.3%), 11 Crocidura lasiura (7. l%) and 1 Micromys minutus (0.6%) From total 12,075 chiggers harvested, 9 species of 4 genera in Trombiculidae were identified. (2) The predominant species through all seasons was 1. setum (43.3%), followed by 1. orientale (27.4%) and 1. scutellare (26.6%). However, in autumn when the most cases of tsutsugamushi disease occur, 1. scutellere was prominently predominant, having 79.8% of the collected chiggers. (3) Among 1,1421. scutellare examined for Rickettsia tsutsugpmushi by means of IFA test, 6 individuals were found positive showing 0.5% of infection rate. This is the first finding that 1. scutellere is the second vector species of tsutsugamushi disease in Korea. (4) Antibody positive rate of A. agrarius chejuensis sera were 31.2% (44/139), and 1 M. minutes serum was also found positive. The seropositive rates by season were not so significantly different. Key words: Tsutsugamushi disease, epidemiology, vector species, Cheju Island, Korea.

• Parasites, Hosts and Diseases
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• v.35 no.3
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• pp.171-180
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• 1997

Studies on geographical distributions and relative population densities of the vector mites of tsutsugamushi disease were carried out in October 1996 at 12 locations of the mid south inland of the Korean peninsula, where chigger mites have been never studied. Of 177 field rodents and insectivores collected. 154 (87.0%) were Apodemus ngrarius. Total 25,707 chigger mites were collected and 14 species were identified. of which Leptotrombidium pnllidum was predominant (79.8%) and L. palpate the next (8.9%) . L. pallidum, the vector species, was widely distributed in all study areas, showing the highest density at Cho-o 2-dong, Sangju-si (chigger index 201.8), and the lowest at Tanwol-dong. Chungiu-si (chigger index 40.7) . The other vector species, L. scutellare was found only at the southern part of the study area such as Yobae and Mipyong, Kumrung gun and Vnsu , Kimchon-si. The northernmost areas of the L. scutellcre distribution were coincided with the areas where actual mean air temperature is above 10.0%. Among 157 A. ograrius sera tested, 48.3% was Karp, 1.7% william and 3.3% Kuroki. The rest of the sera were not able to determine the sexto-type because of the cross antigen-antibody reactions among the tested sero-types.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.257-264
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• 1991

Studies on the geographical distribution and the seasonal prevalence of chigger mites, with particular reference to L. paflidum, a vector species of tsutsugamushi disease were carried out during the period of July 1989-October 1990. From total 111 field rodents collected during the study period, 4,498 chiggers were obtained and 12 species of 4 genera were identified. L. paflidum, the vector species was the dorninant species, showing 65.6% of the total chiggers. L. scutellare, known as the important vector species of tsutsugamushi disease in Japan was not found in the study area, except Yesan-gun, Chungcheong-namdo where only one specimen was collected. The distribution of chigger mites was clearly localized by species, showing the different dominant species by locality. The population density of L. paflidum was high at two study areas, moderate at one area and very low at six other areas, compared to the other species. The study on seasonal prevalence of L. paflidum population density resulted that they started appearing in September (9.8%), showed the peak in October (45.4%) and November (30.6%), almost disappeared during the period of December-March (1.3-0%), reappeared in April (12.7%) showing a small peak, and again almost disappeared until September. L. palpafe was appeared only in winter and spring (December-April).

• Korean Journal of Environment and Ecology
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• v.21 no.1
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• pp.30-37
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• 2007

Pellets and prey remains were analyzed to compare diets and foraging tactics of Eurasian eagle owls (Bubo bubo) in two different habitat types: forested areas and open fields. Overall 150 prey items of three taxa were identified from 66 pellets and 82 prey remains, and the birds were the most important prey in biomass (78.04%) and in frequency (56.67%). Eurasian eagle owls frequently used rats (Rattus spp.), ring-necked pheasants (Phasianus colchicus), and stripped field mice (Apodemus agrarius), but the ring-necked pheasant was most important in biomass in both habitat types. The owls generally foraged various prey in biomass but the mean mass of vertebrate prey used by the Eurasian eagle owls was 503.3g in central Korea. According to the comparison of diets in the two different habitat types, the owls used bigger and more diverse prey in forested areas than in open fields. In forested areas, the Eurasian eagle owls frequently foraged the pheasants and Mandarin ducks (Aix galericulata), but they preferred prey of particular sizes to prey of particular taxa. In open fields, however, the owls showed opportunistic foraging tactics by selecting many small mammals such as rodents or a few large birds.