Helicobacter apodemus sp. nov., a new Helicobacter species identified from the gastrointestinal tract of striped field mice in Korea

A novel Helicobacter species was identified from the gastrointestinal tract of the Korean striped field mouse (Apodemus agrarius). Biochemical testing, ultrastructure characterization, and 16S rRNA gene sequence analysis suggested that this bacterium represents a distinct taxon. The bacterium was positive for urease activity, susceptible to cephalothin and nalidixic acid, and weakly positive for oxidase and catalase activity. Electron microscopy revealed that the bacterium has spirally curved rod morphology with singular bipolar nonsheathed flagella. Genotypically, the isolated bacterial strains (YMRC 000215, YMRC 000216, and YMRC 000419) were most closely related to a reference strain of Helicobacter mesocricetorum (97.25%, 97.32%, and 97.03% 16S rRNA sequence similarities, respectively). The 16S rRNA sequences of these strains were deposited into GenBank under accession numbers AF284754, AY009129, and AY009130, respectively. We propose the name Helicobacter apodemus for this novel species.

Intestinal Helminthic Infections in Striped Field Mice, Apodemus agrarius, from Two Southern Regions of Korea

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.

Echinostome Infections in the Striped-Field Mouse, Apodemus agrarius, and the Ussuri White-Toothed Shrew, Crocidura lasiura, Caught Near the Demilitarized Zone, Gyeonggi-do (Province), Republic of Korea

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.

Morphological Studies of the Neuropeptide Y Immunoreactiive Neurons in the Cerebral Cortex and the Corpus Striatum of Striped Field Mouse (apodemus agrarius coreae) / 대한해부학회지

Neuropeptide Y(NPY) was first isolated from porcine brain. This discovery has led some workers to study the distribution of this peptide in the central nervous system of various mammals. In this study examined the distribution pattern of NPY-immunoreactive (NPY-IR) neurons in the Striped Field Mouse (Apodemus agrarius coreae) cerebral cortex and striatum, using immunohistochemical method. The results obtained in this study were summarized as followings. 1. NPY-IR neurons distributed in all layer of cerebral cortex. The number of neurons were higher in layer V and VI than in layer I and IV. 2. The shape of neurons was predominantly round or oval in layer I and II, and triangular in layer V and VI. And the processes were parallel to pia mater in layer I and II and were vertical in layer III. 3. The highest number of NPY-IR neurons were found in the perirhinal cortex but a few distinct population were found in the retrosplenial cortex. 4. In stiatum NPY-IR neurons were observed only in caudate-putamen nucleus. 5. The Immunoreactive neurons in caudate-putamen varied in their shape, but most of them were triangular or multiform neurons had omnidirectional processes.

Dopaminergic Neurons in the Diencephalon of Striped Field MouseApodemus agrarius coreae / 대한해부학회지

The distributions and morphological characteristics of neurons displaying immunoreactivity to the catecholamine synthetic enzymes, tyrosine hydroxylase[TH], dopamine-beta-hydroxylase[DBH], and phenyletha-nolamine-N-methyltransferase[PNMT] were examined in the adjacent sections of the diencephalon of the striped field mouse [Apodemus agrarius coreae].Only TH-, and no DBH- or PNMT-immunoreactive neurons were found in the diencephalon. In the preoptic area, TH-immunoreactive neurons were found in the anterior preoptic nucleus of Loo[APN], periventricular preoptic nucleus, medial preoptic nucleus, lateral preoptic nucleus and suprachiasmatic nucleus. In the hypothalamus, TH-immunoreactive neurons were found in theparaventricular hypothalamic nucleus, periventricular gray, retrochiasmatic area,anterior hypothalamic nucleus of anterior hypothalamic area and retrochiasmatic region of the hypothalamus. In the rostral tuberal region of the hypothalamus, TH-immunoreactive neurons were found in the paraventricular nucleus, periventricular gray and arcuate nucleus. In the midtuberal region of the hypothalamus, TH-immunoreactive neurons were found in the paraventricular nucleus, dorsomedial hypothalamic nucleus, zona incerta and arcuate nucleus. In the caudal tuberal region of the hypothalamus, dorsal hypothalamic nucleus, posterior hypothalamic complex and arcuate nucleus.