Immunohistochemical and lectin histochemical studies on the developing olfactory organs of fetal camel

Histological evaluation of the alpaca (Vicugna pacos) vomeronasal organ

Little is known about the neuronal structure of the vomeronasal organ (VNO), a receptor organ responsible for pheromone perception, in the alpaca (Vicugna pacos). This study was performed to determine the localization of neuronal elements, including protein gene product 9.5 (PGP 9.5), a pan-neuronal marker, olfactory marker protein (OMP), a marker of mature olfactory receptor cells, and phospholipase C beta 2 (PLC-β2), a marker of solitary chemoreceptor cells (SCCs), in the VNO. OMP was identified in receptor cells of the vomeronasal sensory epithelium (VSE), while PGP 9.5 and PLC-β2 were localized in both the VSE and vomeronasal non-sensory epithelium. Collectively, these results suggested that the alpaca VNO possesses SCCs and olfactory receptor cells, which recognize both harmful substances and pheromones.

Comparative histochemical analysis of glycoconjugates in the nasal vestibule of camel and sheep

While Corriedale sheep survive in a wide range of climates, which prevents them to specialize for one climatic condition only, dromedary camels strictly adapted to desert areas. This demands more adaptive mechanisms to hot, dry conditions in camels than in sheep. Being the entrance of the nasal cavity, nasal vestibule is subjected to various environmental stressors. A protective way is the lining epithelium which is cornified in camel, but not in sheep. Mucus nasal secretions also play a key role in the protection of underlyings. Additionally, arterio-venous anastomosis is present in the lamina propria of the nasal vestibule of camel. In the present paper, sugar residues in the nasal vestibule of camel were analyzed and compared with those of sheep using 14 types of lectins to explore the distribution of glycoconjugates that may help the function of camel nasal vestibule in desert environment. In camel, none of the lectins could label the basal cells of the vestibular epithelium, although the basal cells reacted with six lectins in sheep. In camel, LEL and RCA-120 markedly labeled the luminal surface. WGA, DBA, SBA, and VVA produced marked intensities on the luminal surface in sheep. The mucous glands reacted with six lectins: WGA, s-WGA, VVA, PNA, PHA-E, and PHA-L in camel, while all lectins used except s-WGA and PHA-E reacted in the sheep. In summary, great differences are observed in the glycoconjugate expression between camel and sheep. This suggests that these glycoconjugate are related to camel's tolerance for environmental stressors.

Glycoconjugates pattern and chemosensory cells in the camel respiratory mucosa: Lectin and immunohistochemical studies

The glycoconjugates pattern of acidic secretions and distribution of chemosensory cells (SCCs) in the respiratory mucosa of dromedary camels were analyzed so as to identify their functional role. Secretions of the goblet cells and mucous glandular cells were analyzed to evaluate the variety of sugar chains, focusing on the acidic glycoconjugates. Using lectin histochemistry, WGA, STL, DBA, SBA, VVA and RCA-120 intensely bound to the goblet cells. PNA and ECL labeled the goblet cells with moderate intensity. While, s-WGA, UEA-I faintly bound to them. Lectins bound to the glycocalyx: WGA, LEL, STL, DSL, DBA, SBA, VVA, RCA-120, ECL and PHA-L (tetra- and tri-antennary N-glycans). The mucous secretory cells reacted with: WGA, s-WGA, STL, DBA, SBA, ECL and Con A. Glycoconjugates secreted by the camel respiratory mucosa are rich in sialomucins, glucosaminy-lated residuals with some galactosyl/galactosaminylated residues; few L-fucose and mannosylated sugar residues are also included. For identification of SCCs, the camel respiratory mucosa was immunostained with phospholipase C-β2 (PLC-β2), a taste signaling marker. Several PLC-β2 immunoreactive cells were detected in camel respiratory epithelium. Finally, prevalence of sialomucins and SCCs which can respond to noxious chemicals may suggest a vital role in optimizing physiological and pathological reactions in camel respiratory mucosa.