• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.245-250
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• 2007

This study was conducted to clarify the differences in small rodents characteristics of populations between forest and forest road area in deciduous forest, Jincheon, Chungbuk province, Korea. Value of understory coverage and number of small trees (<10 cm DBH) were higher and value of canopy coverage was lower in forest road area than in forest area. Size of home range of Apodemus peninsulae was larger and number of captured individuals was less in forest area. Also, mean body weight and number of captured individuals of A. agrarius were higher in forest road area. There were differences in captured number of individuals in each distance from the center of planned road route or forest road in both areas. Forest road would be influenced on individuals, species composition, and habitat using pattern of small rodents.

• The Journal of Korean Society of Virology
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• v.28 no.3
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• pp.287-293
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• 1998

Hantaan virus are widely distributed in rodents populations in Korea. Two antigenically distinct hantaviruses have been isolated from Apodemus agrarius in 1976 and Rattus norvegicus in 1980 in Korea. This study was designed to find the serological evidence of hantavirus infection among indigenous wild rodents captured in 7 Mountains located in Kangwon province of south Korea. A total 191 wild rodents of 3 species were trapped in Chumbong mountain, Kali mountain, Hansuk mounatin, Chachil peak, Bukam ridge, Kyebang mountain and Odae mountain in 1997. Serologic evidence for hantavirus infection were tested using hantavirus antigens by indirect immunofluorescent antibody technique (IFA). Among 85 Apodemus agrarius, 77 Apodemus peninsulae and 29 Eothenomys regulus; 8 A. agrarius (9.4%), 11 A. peninsulae (14.3%) and 4 E. regulus (13.8%) were immunofluorescent antibody positive against hantaan virus. IF antibody titers against Puumala virus of 3 E. regulus sera were higher than against hantaan virus. This data suggest that several antigenically distinct hantaviruses have been circulated in rodent populations in Korea.

• Parasites, Hosts and Diseases
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• v.52 no.4
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• pp.419-423
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• 2014

The present study was performed to know the infection status of intestinal helminths in a most common species of field mice, Apodemus agrarius, from 2 southern regions of Korea. Total 133 and 103 mice were collected by the mouse trap in Hapcheon-gun, Gyeongsangnam-do and Gurye-gun, Jeollanam-do, respectively, from July 2005 to June 2006. The small intestine of each mouse was resected and longitudinally opened with a pair of scissors. The intestinal contents were washed with 0.85% saline until the supernatant became clear. Helminths were collected with naked eyes or under a stereomicroscope from the sediment of the intestinal content. More than 11 species of helminths (4 nematode spp., 5 trematode spp., and 2 cestode spp.) were recovered. Among these, heligmosomoid nematodes (97.5%) was the most highly and heavily infected species. As the members of trematodes, Plagiorchis muris, Brachylaima sp., Echinostoma hortense, Echinostoma cinetorchis, and unidentified echinostome larvae were found in the small intestines of 35 (14.8%), 12 (5.1%), 6 (2.5%), 1 (0.4%), and 1 (0.4%) mice respectively. Two species of tapeworms, Hymenolepis nana and Hymenolepis diminuta were also detected in 79 (33.5%) and 21 (8.9%) mice, respectively. Conclusively, heligmosomoid nematodes were the most prevalent (dominant) species among more than 11 helminth species detected, and Brachylaima sp. fluke is newly added in the list of intestinal trematodes in Korea.

• Applied Microscopy
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• v.28 no.1
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• pp.49-62
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• 1998

To investigate the morphological changes of epithelial cells of ductus epididymides by sperm entrance, the Korean striped field mouse, Apodemus agrarius coreae was studied with light and transmission electron microscopy. 1. The diameters of the caput epididymis (Cp) and its lumen were $135\sim145{\mu}(140{\pm}0.5{\mu})$ and $115\sim120{\mu}m(117{\pm}0.1{\mu}m)$. The length and width of the epithelium were $27.0\sim28.5{\mu}m(28.0{\pm}0.1{\mu}m)$ and $4.8\sim5.4{\mu}m(5.1{\pm}0.2{\mu}m)$. 2. The diameters of the corpus epididymis (Cr) and its lumen were $160\sim170{\mu}m(166{\pm}0.2{\mu}m)$ and $140\sim150{\mu}m(145{\pm}0.3{\mu}m)$. The length and width of the epithelium were $17.4\sim18.0{\mu}m(17.6{\pm}0.5{\mu}m)$ and $8.8\sim10.4{\mu}m(9.5{\pm}0.2{\mu}m)$. 3. The diameters of the cauda epididymis (Cu) and its lumen were $270\sim280{\mu}m(275{\pm}0.2{\mu}m)$ and $265\sim275{\mu}m(268{\pm}0.3{\mu}m)$. The length and width of the epithelium were $11.2\sim13.4{\mu}m(12.3{\pm}0.3{\mu}m)$ and $9.2\sim11.2{\mu}m(10.0{\pm}0.2{\mu}m)$. Therefore, the size of diameter and lumen of the ductus epididymides and the width of the epithelium increased from Cp and Cr to Cu, but the length of epithelial cells decreased from Ca and Cr to Cu. These data suggest that the morphological changes of epithelial cells of the ductus epididymides may be the results of the sperm entrance.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.395-404
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• 1995

In order to study the process of spermiogenesis of the korean striped field mouse Apodemus agrorfus coreae, the cell differentiation of seminiferous epithelium and morphological features of mature sperm in cauda epididymis was examined and the results are as follows: Spermiogenesis was divided, according to the features of cell structure; Golgi, cap, acrosome and spermiation phases were further subdivided into two steps of early and late phases respectively, and maturation phase has only one step. Hence, the spermiogenesis consists of nine phases. in the changes of the chromatin in nucleus, the chromatin granules began to be condensed in the cap phase and the condensation proceeded to form a globular of nucleus at the acrsome phase. Finally, the chromatin regularization was completed and perfect nucleus of sperm was formed at the maturation phase. Sperm head had the falciform, and the outer dence fibers of middle piece were arranged in a horseshoe fashion. The outer dence fiber number 1, 5, 6 and 9 was larger than other fiber number 2, 3, 4, 7, 8.

• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.403-411
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• 2020

Adult ascarid worms from the field mice, Apodemus agrarius, were observed with a light and scanning electron microscope, and molecularly analized with 18S rRNA gene. In the scanning electron microscope, 3 prominent labia were present in the anterior end of male and female worms, but the interlabia and gubernaculum were absent. Scanning electron micrographs showed cervical alae as vestigial organs that looked like a slightly uplifted superficial sewing stitch. Total 6 pairs of post-cloacal papillae were observed on the tail of the male worms. The tail of female worms was blunt and conical shape with a spine-like structure, mucron. The eggs were sub-globular, coated with the albuminous layer and 73 by 82 ㎛ in average size. The superficial pits of T. apodemi egg (mean 8.6×6.7 ㎛) are obviously bigger than those of Toxocara spp. The partial sequence of 18S rRNA showed the sequence homology of Toxocara canis (99.6%), Toxocara cati (99.4%), Toxascaris leonina (99.4%), and Toxocara vitulorum (99.2%). Conclusively, it was confirmed that ascarid nematodes, Toxocara apodemi, recovered from striped field mice in Korea are taxonomically conspecific relationship with genus Toxocara and genetic divergence from other Toxocara species.

• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.473-479
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• 2021

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.25-32
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• 2006

This study examined the possibility of using dark-striped field mice as a biological indicator for the environmental radio-surveillance. For this study, dark-striped field mice were caught from five areas of Kyonggi, Kyongsang, Chungchong and Cholla provinces. The external morphological characteristics and isoenzymic types of dark-striped field mice were studied after they were captured. Among the external morphological characteristics, the dark-brown coat, dark back stripe, head-to-tail length, tail length, and ear length matched the taxonomical characteristics of dark-striped field mice. The analyses on L-lactate dehydrogenase, aspartate aminotransferase, and malate dehydrogenese revealed that one species of dark-striped field mice, called Apodemus agrarius, was inhabitated throughout a wide range of Korea. On the other hand, the frequency of micronuclei in peripheral polychromatic erythrocytes to survived mice after irradiation also analyzed. The LD50/30 of A. cgrarius and ICR mice were approximately 5 Gy and 7.9Gy, respectively. The results of the study reveal that wild A. asrarius have a high potential as a biological monitoring system to determine the impact of radiation in areas such as those within the vicinity of nuclear power plants.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.168-173
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• 2015

The present investigation was planned to estimate potential possibility of striped field mice, Apodemus agrarius coreae (A. a. coreae), as a biological dosimeter in radio-environmental ecology. We bred captured wild A. a. coreae at laboratory and classified taxonomically based on external, cranial and tooth characters. Organ weights and splenocytic apoptosis were observed in order to establish a basic data on radiation biology of A. a. coreae (male, 40 weeks old). The biological effects was observed at 24hrs following irradiation (doses : 0, 0.5, 1, 2 Gy, dose rate : $0.8Gymin^{-1}$, $^{137}Cs$). Only thymus weights was significantly decreased. Splenocytic apoptosis was increased after irradiation. But splenocytic apoptosis was decreased in 0.5 Gy ${\gamma}$-irradiated mice compared to those of 0, 1, 2 Gy (P < 0.05). These data suggested that events in thymus and spleen of Korean dark-striped field mice, A. a. coreae THOMAS, could be a potential radio-biological indicator in human environments.

• Journal of Life Science
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• v.16 no.4
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• pp.618-625
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• 2006

Patterns of induced daily torpor were measured in the striped field mouse, Apodemus agrarius, in response to low temperature, food deprivation and various photoperiods using implanted data loggers. A total of 8 of 21 females entered daily torpor in response to low outside ambient temperature (Ta) during winter and spring, constant low Ta $(4^{\circ}C)$ or food deprivation $(23^{\circ}C)$ during summer, but 2 of 23 males did only in response to low outside Ta during winter. This fact indicates that torpor is an adaptive hypothermia to unpredictable environment in both some males and females, as well as that torpor was inhibited in males in the reproductive season as in other mammals, which is regarded as a strategy not to reduce the chance of copulation. As for females, however, torpor was employed in response to unpredictable environment even in the reproductive season, suggesting that alternative strategies other than keeping the chance of copulation maybe hired by females to keep the population. Torpor bout generally began at $6{\sim}12$ AM, but the decrease of body temperature $(T_b)$ began mainly at $4{\sim}6$ AM at any conditions, the time when Ta is lowest. This strategy might be also adopted for reducing heat loss to unpredictable environment. Minimum $T_b$ of both males and females during torpor did not fall below $16.5^{\circ}C$. Photoperiod had no influence on the incidence and timing of daily torpor in either males and females. The similar timing of torpor bout in response to the 3 different photoperiods (24D, 16L:8D or 8L:16D) under the constant temperatures $(4^{\circ}C\;or\;23{\pm}2^{\circ}C)$ suggests that entering time of torpor might be controlled by the circadian rhythm of the mice rather than by the photoperiod.