This study explores the histological features and Bmp4 expression patterns in the replaced tooth germ of Xenopus laevis . Tooth germ formation starts from the dental placode through epithelial-mesenchymal interactions, involving various signaling pathways such as Fgf, Shh, Bmp, and Wnt. In mice, Bmp4 expression in the dental placode inhibits Pax9 expression in the dental mesenchyme. Although absent in the presumptive dental lamina of birds and toothless mammals, Bmp4 remains conserved in reptiles and fish owing to gene duplication. However, its expression in amphibian tooth germs is poorly understood. Three-month-old X. laevis were employed in this study. Initially, samples underwent paraffin embedding and were sectioned into 5 or 12 μm ribbons for H&E staining and in situ hybridization, respectively. Results revealed teeth appearing in two maxillary rows: the labial side, with prefunctional and functional teeth, and the lingual side, with replaced tooth germs behind functional teeth. Enameloid was observed between the inner dental epithelium and dental mesenchyme at the cap or early bell stages, whereas enamel and dentin formed during the late bell or mineralization stages from the replaced tooth germ. Bmp4 expression was evident in the inner dental epithelium (ameloblasts), dental papilla (odontoblasts), stellate reticulum, and Hertwig’s epithelial root sheath. Overall, these findings highlight the conservation of Bmp4 expression in X. laevis tooth development.

The vomeronasal organ (VNO) is critical for reproduction and social behavior in ruminants, including cattle. The present study examined the structure of the VNO and its epithelial cells in neonatal and adult Korean native cattle (Hanwoo), Bos taurus coreanae , using immunohistochemistry and lectin histochemistry. Histologically, the VNO comprised two types of epithelia: medial vomeronasal sensory (VSE) and lateral vomeronasal non-sensory epithelia (VNSE). Numerous blood vessels and nerve bundles were observed within the vomeronasal cartilage encased lamina propria. Immunohistochemistry revealed high expression level of protein gene product9.5 and moderate expression level of olfactory marker protein in the neuroreceptor cells of the VSE and occasionally in some ciliated cells of the VNSE in both neonates and adults. The properties of the glycoconjugates in the VNO were investigated using 21 lectins, most of which were expressed at varied intensities in the VSE and VNSE, as well as in the lamina propria. Several lectins exhibited variations in their intensities and localization between neonatal and adult VNOs. This study is the first descriptive lectin histochemical examination of the VNO of Korean native cattle with a focus on lectin histochemistry, confirming that the VNO of Korean native cattle is differentiated during postnatal development.

본 연구는 열 스트레스 하에서 오리사료 내 대사에너지(ME) 수준이 오리의 간, 십이지장 융 모, 미생물, 유전자 조절에 미치는 영향을 조사하였다. 총 240마리의 육용 오리 채리밸리(Anas platyrhynchos)를 4처리구로 완전임의배치 한 후 42일 동안 사육하였다. 처리구는 ME 2900 kcal/kg, ME 3000 kcal/kg, ME 3100 kcal/kg 및 ME 3200 kcal/kg로 구분하였다. 간 조직은 처리구 사이의 차이가 없었고, 십이지장 융모 및 창자샘 길이는 ME 3000과 비교할 때 2900은 10.58% 감소하였으나 3100, 3200과의 사이에 차이는 없었다. 맹장 Latobacillus는 ME 3000과 비교할 때 2900은 9.47% 감 소하였으나 3100, 3200은 각각 2.52, 3.24% 증가하였다. Total aerobic bacteria, E. coli, Coliform bacteria는 ME 3000과 비교할 때 2900은 증가하였으나 3100, 3200은 차이가 나타나지 않았다. 간에서 HSP (heat shock proteins)-mRNA 중 HSP 90-α는 ME 3000과 비교할 때 2900은 48.60% 감소하였 으며 3100, 3200은 차이가 없거나 증가하였다.

The histological changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. The retinas size of both species increased in the 9 days post-hatching (DPH) (p<0.05). In the just-hatched Ussurian bullhead, the retina already consisted of six layers: the epithelial layer, ganglion cell layer, inner nuclear layer, inner plexiform layer, outer limiting membrane layer, and rod and cone layer. The Korean bullhead had the same components. At 50 DPH, the thickness of the retina was 538.0±7.19 μm in the Ussurian bullhead and 558.9±9.44 μm in the Korean bullhead. The relative thickness of each layer of the retina did not differ significantly in the two species. Although the growth of the Korean bullhead’s retina was faster, the relative thickness of each layer in the retina did not change during early development. After hatching, some parts of the tissue gradually became denser. Immediately after hatching, the kidney and midgut epithelium of the Ussurian bullhead and Korean bullhead were already formed and grew gradually thereafter. From 0 DPH to 30 DPH, the nuclear height in the midgut epithelium did not differ significantly between the two species, but at 50 DPH, it was 11.4±2.45 μm in the Korean bullhead and 9.9± 2.13 μm in the Ussurian bullhead. During the experimental period, the major axes, minor axes, surface areas, and volumes of the proximal tubule cells in the kidney did not differ significantly between the two species. Thus, the early histological development of the Ussurian bullhead is similar to that of the Korean bullhead.