Sex and Ontogenetic Variation in the Crest of Numida meleagris: Implications for Crested Vertebrates

Crested vertebrates are known from a wide variety of modern and fossil taxa, however, the actual formation and function of the crest is still debatable. Among modern birds, the globally distributed guinea fowl (Numida meleagris) is characterized by having a cranial bony crest (overlain by keratin), but surprisingly little is known about its development. Here, we studied the crest of 202 wild guinea fowl from the same population, using anatomical measurements as well as 2D-morphometry. Our results show that juveniles have smaller skulls than adults and have smaller, simpler crests that are visible even in very young individuals. Among adults, female skulls are smaller than males, and they have smaller, simpler shaped crests, which permit a discrimination between the sexes of 93% when the keratin is preserved with the bony crest, and of 89% when only the bony crest is available. By extrapolation, these results confirm that the crest can be used as an ontogenetic character, as well as for sex discrimination in the fossil record. Our results also show that the overlying keratin does not always mimic the underlying bony crest, which should be considered when reconstructing extinct crested vertebrates. Anat Rec, 303:1018–1034, 2020. © 2019 American Association for Anatomy     

Natural immunodominant and experimental autoimmune encephalomyelitis-protective determinants within the lewis rat Vβ8.2 sequence include CDR2 and framework 3 idiotopes

The Vβ8.2-39-59 peptide has served as a prototypic natural regulatory idiotope in Lewis rats developing experimental autoimmune encephalomyelitis (EAE). The purpose of the present study was to determine if additional regulatory regions were contained within the Vβ8.2 sequence expressed by most encephalogenic T cells. A comprehensive strategy utilizing Vβ8+ hybridomas, a recombinant (r) Vβ8.2 molecule, and overlapping synthetic Vβ8.2 peptides reconfirmed the natural recognition of the 39-59 idiotope, and revealed a second immunodominant and EAE-protective determinant residing within residues 71-90. Both the Vβ8.2-39-59 and Vβ8.2-71-90 peptides were immunogenic, and each was recognized after immunization of Lewis rats with Vβ8+ cells or rVβ8.2, indicating the preservation of these epitopes during the processing of the Vβ8.2 chain. Moreover, both epitopes were recognized naturally by T cells from rats developing or recovering from EAE that had never been purposefully immunized with Vβ8.2 peptides or rVβ8.2. Of additional interest, the Vβ8.2-31-50 peptide was recognized by T cells from some rats immunized with complete Freund's adjuvant (CFA) alone. This peptide possessed mildly protective activity against EAE and thus could account for sporadic reports of CFA interference in EAE. © 1996 Wiley-Liss, Inc.     

冷热水前庭刺激对豚鼠前庭内侧核5-羟色胺能系统的影响

目的研究前庭神经系统在受到冷热水刺激诱发眩晕后前庭内侧核5-羟色胺的变化规律,探讨神经递质在眩晕发生时的作用。方法利用微透析技术研究冷热水注人豚鼠耳道时对其前庭内侧核5-羟色胺的影响。结果冷热水刺激诱发了豚鼠的前庭性眼震,分别持续60秒和90秒,37℃水灌流外耳道以及冷热水刺激耳廓时均无眼震出现。外耳道灌流44℃热水和0℃冰水在10分钟时显著升高前庭内侧核5-羟色胺水平至基线水平的189％和254％,并且持续升高5分钟。37℃水灌流外耳道以及冷热水刺激耳廓时5-羟色胺水平无明显变化。结论前庭内侧核5-羟色胺水平的升高可能与冷热水刺激末梢前庭系统所诱发的眩晕发生有关。5-羟色胺可能作为一种神经调节物质发挥作用的。     

Spatiotemporal Expression Patterns of Critical Genes Involved in FGF Signaling During Morphogenesis and Odontogenesis of Deciduous Molars in Miniature Pigs

The fibroblast growth factor (FGF) pathway plays an important role in epithelial-mesenchymal interactions during tooth development. Nevertheless, how the ligands, receptors, and antagonists of the FGF pathway are involved in epithelial-mesenchymal interactions remains largely unknown. Miniature pigs exhibit tooth anatomy and replacement patterns like those in humans and hence can serve as large animal models. The present study investigated the spatiotemporal expression patterns of critical genes encoding FGF ligands (FGF3, FGF4, FGF7, and FGF9), antagonists (SPRY2 and SPRY4) and receptors (FGFR1, FGFR2, and FGFR3) in the third deciduous molars of miniature pigs at the cap (embryonic day 40, E40), early bell (E50), and late bell (E60) stages. The results of in situ hybridization (ISH) with tyramide signal amplification and of qRT-PCR analysis revealed increased expression of FGF7, FGFR1, FGFR2, and SPRY4 in dental epithelium and of FGF7 and FGFR1 in mesenchyme from E40 to E50. In contrast, the results revealed decreased expression of FGF3, FGF4, FGF9, and FGFR3 in dental epithelium and of FGF4, FGF9, FGFR2, and FGFR3 in the mesenchyme from E40 to E60. Mesenchyme signals of FGF3, FGF4, FGF7, SPRY2, FGFR2, and FGFR3 were concentrated in the odontoblast layer from E50 to E60. The distinct expression patterns of these molecules indicated elaborate regulation during dental morphogenesis. Our results provide a foundation for further investigation into fine-tuning dental morphogenesis and odontogenesis by controlling interactions between dental epithelium and mesenchyme, thus promoting tooth regeneration in large mammals.