A new species of the genus Pseudocrangonyx (Crustacea: Amphipoda: Pseudocrangonyctidae) from subterranean waters of Japan.

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx asuwaensis, is described from subterranean water in a quarry on Mt. Asuwa "Nanatsuo-guchi", Fukui Prefecture, Japan. Pseudocrangonyx asuwaensis sp. nov. differs from its congeners in various morphological features, such as head without eyes, relative length of antennae 1, female antenna 2 without calceoli, length ratio of mandibular palp articles, setal numbers on maxillae 1 and 2 inner plates, absence of sternal gills, armature of urosomite 1, and shape of telson. Molecular phylogenetic analyses suggest that P. asuwaensis sp. nov. is clustered with P. komaii Tomikawa & Nakano, 2018, Pseudocrangonyx sp. 7 and Pseudocrangonyx sp. 8, and was the first of these species to diverge.

Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae).

Two new species of Maera Leach, 1814 and Quadrimaera Krapp-Schickel Ruffo, 2000 included in the Maera-clade are described from Japan. Maera denticoxa sp. nov. was collected from Iwate and Hokkaido Prefectures and can be distinguished from its congeners by the small notches on the posteroventral margins of coxae 1-6. Quadrimaera angulata sp. nov. from north of Tanegashima Island in Kagoshima Prefecture is characterized by the distal tooth on the mandibular palp article 1, the rounded palm of the female gnathopod 2, and the angular posterodistal margin of the pereopod 7 basis. Keys to Japanese species of the Maera-clade are provided. In total, seventeen species included in the clade occur in Japan.

A new species of the genus Pseudocrangonyx (Crustacea: Amphipoda: Pseudocrangonyctidae) from Simbok Cave, Korea.

A new subterranean species of pseudocrangonyctid amphipod, Pseudocrangonyx joolaei, is described from the groundwater of a cave in South Korea. Pseudocrangonyx joolaei sp. nov. can be distinguished from its congeners by the number of sternal gills as well as a combination of the antennal sinus, the accessory flagellum of antenna 1, and the terminal article of uropod 3. Molecular phylogenetic analyses based on nuclear 28S rRNA and histone H3, and mitochondrial cytochrome c oxidase subunit I and 16S rRNA genes revealed that P. joolaei sp. nov. formed a clade with P. akatsukai Tomikawa Nakano, 2018 that inhabits limestone caves in the western Honshu island, Japan.

A new species of the genus Rhachotropis from off Amamioshima Island, northwestern Pacific (Crustacea: Amphipoda: Eusiridae).

A new species of the eusirid amphipod, Rhachotropis reiwa is described from off Amamioshima Island, northwestern Pacific. The new species differs from its congeners in having large eyes, the middorsal tooth on pereonite 7, pleonite 3 and urosomite 1 without middorsal and dorsolateral teeth, the basis of pereopod 5 strongly produced posteriorly, and pereopod 6 with the triangular basis. A key to the species of Rhachotropis from Japanese and adjacent waters is provided. Additionally, a nucleotide sequence of mitochondrial cytochrome c oxidase subunit I from its holotype was determined for the future study.

Opisa takafuminakanoi, a new species of Opisidae from Hokkaido, Japan (Crustacea: Amphipoda).

Opisa is a small amphipod genus including three species: O. eschrichtii (Krøyer, 1842) from the North Atlantic Ocean (Sars 1895; Bousfield 1987), the Arctic Ocean (Bousfield 1987), and the western Pacific Ocean (Stebbing 1906; Derzhavin 1929); O. odontochela Bousfield, 1987 from the southeast Alaska (Bousfield 1987); and O. tridentata Hurley, 1963 from the Pacific coasts of North America (Bousfield 1987). During field survey of the marine benthic fauna of Hokkaido, Japan, one of the authors (KK) collected an undescribed species of Opisa from off the southeast of Akkeshi Bay using a sledge net. This paper describes and illustrates the new species in detail.

Overexpression of Smad2 inhibits proliferation of gingival epithelial cells.

BACKGROUND AND OBJECTIVE: Spatiotemporal inhibition of apical migration and proliferation of gingival epithelium are significant factors involved in periodontal regeneration. Transforming growth factor ß (TGF-ß) is important in multiple aspects of wound healing, and Smad2, a downstream transcription factor of TGF-ß, has an inhibitory effect on re-epithelialization during gingival wound healing. Therefore, we investigated the effects on migration and proliferation status, and intra/extracellular signaling regulated by Smad2 overexpression in gingival epithelial cells. MATERIAL AND METHODS: Gingival epithelial cells were isolated from the palatal gingival tissue of transgenic mice overexpressing Smad2 driven by the Keratin14 promoter. Smad2 expression was identified by western blotting and immunofluorescence analysis. Scratch assay and 5-bromo-2'-deoxyuridine staining were performed to assess cell migration and proliferation. To inactivate TGF-ß type I receptor, the cultures were supplemented with SB431542. Secreted TGF-ß was quantified by ELISA. Smad2 target gene expression was examined by real-time RT-PCR and in vivo immunofluorescence analysis of gingival junctional epithelium. RESULTS: Smad2-overexpressing cells were confirmed to have significant phosphorylated Smad2 in the nucleus. Scratch assay and 5-bromo-2'-deoxyuridine staining indicated that Smad2-overexpressing cells showed no significant differences in migration, but had reduced proliferation rates compared to wild-type controls. SB431542 significantly inhibited Smad2 phosphorylation, which coincided with restoration of the proliferation rate in Smad2-overexpressing cells. ELISA of TGF-ß release did not show any differences between genotypes. The cell cycle inhibitors, p15 and p21, showed significant upregulation in Smad2-overexpressing cells compared to wild-type controls. Moreover, junctional epithelium of the transgenic mice showed increased expression of P-Smad2, p15 and p21. CONCLUSION: The signaling activation triggered by overexpression of Smad2 was dependent on TGF-ß type I receptor, and the activated Smad2 increased p15 and p21 expression, responsible for inhibiting cell cycle entry, resulting in antiproliferative effects on gingival epithelial cells. Understanding of Smad2-induced signaling would be useful for possible clinical application to regulate gingival epithelial downgrowth.

Smad2 decelerates re-epithelialization during gingival wound healing.

During periodontal regeneration, inhibition of gingival downgrowth is necessary to promote migration of mesenchymal cells into the defects. Transforming growth factor (TGF)-ß is a pleiotropic cytokine that has numerous cell functions, including regulation of epithelial growth. Recent studies have shown that Smad2, a downstream transcription factor of TGF-ß, plays crucial roles in wound healing in the epithelia. Therefore, we investigated the effects of Smad2 overexpression on re-epithelialization of gingival wounds. Transgenic mice overexpressing smad2 driven by the keratin 14 promoter (k14-smad2) were confirmed to have significant Smad2 phosphorylation in gingival basal epithelia. Punch wounds were made in the palatal gingiva, and wound healing was assessed histologically for 7 days. Re-epithelialization was significantly retarded on day 2, while collagen deposition was enhanced on day 7 in k14-smad2 compared with wild-type mice. Moreover, expression of keratin 16 (K16), an indicator of keratinocyte migration, was significantly inhibited in wound-edge keratinocytes in k14-smad2. The inhibition of K16 coincided with the induction of Smad2 in the corresponding epithelia, while BrdU incorporation was unaffected. These results indicated that Smad2 has inhibitory effects in regulating keratinocyte migration during gingival wound healing. TGF-ß/Smad2 signaling mediating alteration of K16 expression must be tightly regulated during periodontal regeneration.