• 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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.2
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• pp.59-65
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• 2022

Rodent model for chronic cerebral hypoperfusion caused by bilateral carotid artery occlusion (BCAO) show clinically relevant evidences for vascular dementia and impairments of synaptic plasticity in the hippocampus. The purpose of this study was to evaluate effect of fermented garlic (F-Garlic) extract with NO metabolites on cognitive behaviors, synaptic plasticity, and molecular events in the hippocampus following BCAO. Adult male Sprague-Dawley rats were randomly divided three experimental groups into: control+water; BCAO+water; BCAO+F-Garlic. Animals were treated with oral administration of F-Garlic in tap water as a drinking water after surgery for 4 weeks. On passive avoidance test and Y-maze test, BCAO+water showed a significant decrease in step-through latency and spontaneous alteration, indicating deficit of hippocampal memory formation but the treatment of F-Garlic significantly increased these cognitive behaviors. In control+water, a robust increase in the amplitude of evoked field excitatory postsynaptic potentials was observed by theta burst stimulation to hippocampal neural circuit indicating formation of long-term potentiation (LTP) in the hippocampal CA1. BCAO+water showed a highly significant deficit in LTP induction 4 weeks after BCAO. On other hand, daily oral administration of F-Garlic extract caused the marked preservation of LTP induction. Moreover, parvalbumin was markedly reduced in the CA1, especially, in the stratum radiatum of BCAO+water. In contrast, BCAO+F-Garlic mitigate a significantly reduction of the parvalbumin. In summary, these results suggest that daily oral administration of F-Garlic extract can ameliorate cognitive memory deficit through the preservation of synaptic plasticity and interneurons integrity in the hippocampus in rodent model of chronic cerebral hypoperfusion.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.242-246
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• 2016

The distribution and population density of rodents and chigger mites were investigated between April 2013 and November 2013 in the Gokseong-gun of Jeollanam-do, Korea. A total of 79 rodents were collected using Sherman collapsible traps, and among them, 73 were Apodemus agrarius (92.4%), 4 were Crocidura lasiura (5.0%), and 2 were Microtus fortis (2.5%). Sixty-eight out of the 79 rodents were parasitized by chiggers, showing an infestation rate of 86.0% and a chigger index of 74.5; the chigger index of A. agrarius was 75.4. From the trapped field rodents, 5,063 chigger mites were collected and identified with 6 species of 2 genera. Leptotrombidium scutellare was the dominant species with 3,535 chiggers (69.8%), followed by L. pallidum with 777 chiggers (15.3%). This results showed that the distribution of chigger mites differ in dominant species according to seasons. L. pallidum was the predominant chigger collected in April (34.3%), May (70.0%), and June (55.1%); whereas L. scutellare was the predominant chigger collected in September (75.5%), October (71.8%), and November (74.2%).

• Animal Systematics, Evolution and Diversity
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• v.11 no.1
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• pp.87-100
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• 1995

Fauna of medically important arthropods in Chindo Island was studied in July 1994. Among eight speices of mosquitoes (Diptera : Culicidae), Culex tritenirohyunchus was predomiant (46.5% of the total0, and Anopheles sinensis the next. Seven specimens of the unidentified Culex sp. which seemed to be new were also collected. Total 23 species of non-biting midges(Diptera : Chiornomidae) were found in Chindo Is. Of them , Chironomus kiiensis was the predominant species (67.3%) , and Ch.flaviplumus the next (15.6%). Three species, Cladopelma viridula, Dicrotendipes septemmaculatus and Harnischia urtilamellata are reported for the first time in Korea, and they are fully re-described with illustrations. Among five species of biting midges (Diptera : Ceraopogenidae) collected, Culicoides punctatus was predominant (88.7%). A species of Foreipomia was also collected, and this genus is not recorded in Korean fauna. Only two species of domiciliary cockroaches, Periplaneta japonica and P.americana were collected in small numbers and Blatella germanica which is known as the most predominant speices in Korea was not found. The predominant speices of field rodents was Apodemus agrarius and thier ectoparasites were Leptotrombidium orientale (Acarina : Tromicibulidae), Lxodes nipponensis (Acarina : Ixodidae) ; Laelaps jettmani and Eulaelaps stabularis (Acarina : Laelapidae).

• Parasites, Hosts and Diseases
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• v.56 no.3
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• pp.301-304
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• 2018

Rodents are important reservoirs of diseases affecting people and livestock, and are major sources of parasite contamination of agricultural products. We surveyed the infection status of intestinal helminths in 2 species of field mice, Apodemus agrarius and A. peninsulae, captured in the agricultural fields of Gangwon-do and Chungcheongnam-do, Korea. Total 83 mice (57 A. agrarius and 26 A. peninsulae) were collected in 2 surveyed areas, and the intestines of each mouse were opened with scissors, and then intestinal contents were examined with microscope. Total 6 species of intestinal helminth were detected in 61 (73.5%) out of 83 mice examined. Four species of nematode, i.e., Nippostrongylus brasiliensis, Aspiculuris tetraptera, Heterakis spp. and ascarid, were found in 40 (48.2%), 14 (16.9%), 11 (13.3%) and 13 (15.7%) mice respectively. One species of cestode, Hymenolepis diminuta and 1 unidentified egg were also detected in the intestines of 14 (16.9%) and 1 (1.2%) mice, respectively. Conclusively, this study identified 5 helminth species in the gastrointestinal tracts of wild rodents captured in some areas in central and northern Korea, and N. brasiliensis was the most prevalent (dominant) species rather than zoonotic ones.

• Korean Journal of Environment and Ecology
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• v.37 no.5
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• pp.337-346
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• 2023

Although wildlife bridge are built as a way to reduce habitat fragmentation caused by road construction, there is still a lot of debate about their effectiveness. Monitoring methods such as footprint traps and camera traps are used evaluate the effectiveness of wildlife bridge, but there is a limit to evaluate of effectiveness. In this study, the degree of use the wildlfe bridge was surveyed by striped field mouse that is likely use the wildlife bridge and surrounding as a habitat with capture-mark-recapture method.(Apodemus agraius). The distance and route of movement were identified by connecting the capture points, and the environmental factors on the use of the wildlife bridge implemented a generalized linear model(GLM) with the capture number of captured as a dependent variable. Consequently of capture, no individuals crossing the wildlife bridge, striped field mouse use the wildlife bridge as a habitat.The environmental factors affecting the use of mice were vegetation cover(1~2m, 2~8m, over 8m), vegetation construction, maximum diameter at breast height were positively correlated and slope was nagatively correlated. In conclusion, it is expected that the effectiveness of the wildlife bridge will be further improved by planting shrubs and trees and preventing high slope and cut slope increasing the utilization of the rat, such as being used as a food source in the ecosystem.

• The Journal of Korean Society of Virology
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• v.28 no.4
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• pp.327-335
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• 1998

Hantaan (HTN) and Seoul (SEO) viruses, murid rodent-borne hantaviruses, are known to causes hemorrhagic fever with renal syndrome (HFRS) in Korea. To determine the genomic diversity and molecular phylogeny of HTN and SEO viruses found in Korea, we amplified for part of M and S genomic segments of hantaviruses from sera of HFRS patients and lung tissues of hantavirus seropositive striped-field mice. Both M and S segment of 16 HTN and 2 SEO viruses were amplified by nested reverse transcription-polymerase chain reaction. Based on 324 nucleotides in the M genomic segment, the HTN and SEO strains showed $93.8{\sim}100%$ and $99.1{\sim}99.4%$ homologies, respectively. Similarly, based on 230 nucleotides in the S genomic segment, HTN and SEO strains showed $90.9{\sim}100%$ and 100% homologies, respectively. Phylogenetic analysis of M and S segments indicated that HTN strains could be divided into at least two main groups in M and S trees and the sequence differences detected among the Sand M genomic segments of HTN viruses are consistent with reassortment having taken place between HTN virus strains.

• 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.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.98-117
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• 1994

To provide data for the contents regarding environmental health (environmental hygiene, environmental pollution) in the textbooks of primary, middle and high schools, a total of 243 textbooks was analysed for two months from May, to July 31, 1993. Among the total 52844.50 pages, 1.65% was related to the environmental health, which account for 870.00 pages. In the textbooks by school level, the rate of the contents regarding environmental health in primary school was 1.63% (148.75 pages). that of middle school was 1.96% (243.25 pages) and that of high school was 1.53% (478.00 pages). The area of environmental hygiene was 0.24% (129.25 pages) and that of environmental pollution was 1.40% (740.75 pages) which is slightly high. In the field of environmental hygiene, the rate of the contents in the middle school textbooks was 0.53% which was the higher than that of the primary and high school textbooks. The rate of environmental pollution area was not significantly different by school level but the number of the pages was the higher at the high school than that of the primary and middle schools, which account for 428.8 pages. The contents related by the areas were as follows: 1. Contents related to environmental hygiene 1) Among environemtnal hygiene contents, the rate of housing sanitation was the highest as 0.14% (73.00 pages), that of air environment was 0.06% (33.00 pages) and that of water supply sanitation was 0.03% (17.25 pages). The portion of air environment was 5.00 pages in the primary school textbooks and that of housing sanitation at the middle and high schools was each 35.0 pages, 35.50 pages, which was the more than that of other fields. By school year, there was no contents related at the 1st and 2nd grades but were 4.75 pages at the 4th grade which were the more than those of other grades. At the 5th grade, water supply sanitation part was found but not air environment. Housing sanitation was found at the 3rd, 5th grades and insect or rodent control was at the 3rd, 4th, 5th, 6th grades. 2) In the middle school textbooks related to environmental health, 41.0 pages were included in the textbooks of pysical education, the highest number. The next was 19.5 pages in home economics, 2.8 pages in social studies and 3.00 pages in others. The contents of air environment were found in the textbooks of physical education and science, those of water supply and housing sanitation were in home economics and physical education and those of insect control were found 0.5 pages in home economics only. 3) In the high school textbooks, the highest number was 27.8 pages of home economics and the next was 11.5 pages of others, 7.8 pages of physical education, 2.0 pages of science and 0.3 pages of social studies. Air environment parts were included in the textbooks of science, physical education and home economics and water sanitation was in home economics, physical education and others. Housing sanitation was showed in home economics and social studies, on the other side the contents of insect or rodent control was found in home economics and physical education. 4) By the subjects related to environmental hygiene in the primary, middle and high school textbooks, 51.0 pages of home economics were the highest portion. It was also revealed that 49.5 pages of physical education, 14.5 pages of others, 13.5 pages of science and 0.8 pages of social studies were included. The number of 33.0 pages of air environment portion was distributed into 9.75 pages of science, 19.0 pages of physical education and 4.25 pages of others. Among 17.3 pages of water sanitation, 3.5 pages of home economics, 11.3 pages of physical education and 2.5 pages of others were included. Housing sanitation portions were 73.0 pages, which were distributed into 46.5 pages of home economics, 0.5 pages of social studies, 18.3 pages of physical education and 7.8 pages of others. 5) The number of photo, figure, illustration and table related in the primary school textbooks was 31. Among them, the number of photos was 21, that of figures or illustrations was 9 and that of table was 1. The number of 63 in the middle school textbooks was classified into 3 photos, 32 figures or illustrations and 28 tables. At the high school, the number of 56 was included 2 photos, 41 figures or illustrations and 13 tables.2. Contents related to environmental pollution 1) In the field of environmental pollution, the rate of water pollution was 0.39% (203.3 pages), that of air pollution was 0.31% (161.5 pages) that of soil pollution was 0.1% (57.3 pages), that of refuse disposal was 0.08% (40.3 pages) and others was 0.5% (278.5 pages) by school level, the rate of water pollution in the primary, middle and high schools was each 40.5, 48.0, 118.8 pages and that of air pollution was each 20.8, 38.3, 102.5 pages. 2) Environmental pollution areas were not inserted in the textbooks at the 1st grade of the primary school but foqnd 5.5 pages at the 2nd grade, 30.5 pages at the 4th grade, 36.3 pages at the 5th grade and a,9.5 pages at the 6th grade. Water pollution was included from the 2nd grade, air pollution and refuse disposal from the 3rd grade and soil pollution from the 5th grade. 3) In the middle school textbooks, environmental pollution was distributed into 90.25 pages of science, 42.8. pages of physical education, 20.5 pages of social studies, 19.5 pages of others and 4.0 pages of home economics. At the high school, the contents were found 191.3 pages in science, 119.3 pages in others, 88.5 pages in social studies, 28.5 pages in physical education and 1.3 pages in home economics. 4) By subjects of the primary, middle and high schools, the portion of environmental pollution was classified into 322.2 pages of science, 195.0 pages of social studies, 138.8 pages of others, 76.3 pages of physical education and 8.5 pages of home economics. Air and soil pollution parts were not found in the subjects of home economics. 5) The number of photo, figure or illustration and table related in the primary school textbooks was 218. Among them, the number of photos was 61, that of figures or illustrations was 149 and that of tables was 8. At the middike school, the number of 153 was distributed into 99 photos, 34 figures or illustrations and 20 tables. The number of 129 found in the high school textbooks was included 129 photos, 73 figures or illustrations and 100 tables.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.153-159
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• 2020

The chigger mite Leptotrombidium sialkotense is one of the 6 main vectors of scrub typhus in China. Before present study, L. sialkotense was found in some parts of Hunan province, China with a narrow geographical distribution. During field investigation 2016-2017, we found L. sialkotense in Jingha, southern Yunnan, China. Of 15 small mammal host species, L. sialkotense were collected from 6 species of the hosts. Rattus brunneusculus was a dominant host of L. sialkotense, from which 98.3% of the mites were collected. The chigger mite showed a relatively high infestation prevalence (P_M =11.7%) and mean abundance (MA=0.5) in comparison with the rest 5 host species. These results reveal a certain host specificity of L. sialkotense to a rat R. brunneusculus. The mite L. sialkotense showed an aggregated distribution on the host (P<0.05). A positive correlation observed between L. sialkotense and the body length of hosts. There was a positive interspecific association between L. sialkotense and 2 other dominant vectors, L. deliense and L. scutellare.