Histological characterization of the lingual tonsils of the one-humped camel (Camelus dromedarius)

Ultrastructure of the palatine tonsils of the donkey (Equus asinus): New insights by light, scanning, and transmission electron microscopy

The study aimed to explore the ultrastructure of the donkeys' palatine tonsils. Palatine tonsils of five male donkeys (5 years old) were investigated macroscopically and microscopically. The tonsils appeared as a dome shape with slight elevation and a circular opening on the surface of the oropharynx. The central tonsillar crypt appeared on the medial side of the palate-pharyngeal folds and the floor of the oropharynx. The external surface of the palatine tonsil had different sizes of mucosal folds, some grooves directed to drainage at the tonsillar opening, and the tonsil crypt opening was a crescentic or irregular oval shape. The outer surface was covered by stratified squamous epithelium and modified to be reticular epithelium invaded by lymphocytes in the crypt called lympho-epithelium. The tonsil crypt had aggregated lymphoid nodules, and the cryptal epithelium has surrounded by diffused lymphocytes and hassles corpuscles-like structures. The lymphocytes infiltrated into different layers of the cryptal epithelium and transformed into reticular or lympho-epithelium. The organized lymphoid nodules were primary and secondary, and the secondary ones had a light germinal center. The interfollicular area had many high endothelial venules and blood capillaries. The endothelial venules were lined by simple cuboidal epithelium and had lymphocytes. The blood capillaries had red blood cells and neutrophils. The tonsil was surrounded incompletely by a connective tissue capsule with mucous glands under that capsule. In conclusion, the epithelial lymphocyte infiltration, crypt epithelium, lymphoid nodules, and intra-follicular area of the donkey's palatine tonsils indicate the humoral and cell-mediated immunological process.

Structural and Functional Characterization of Camelus dromedarius Glutathione Transferase M1-1

Glutathione transferases (GSTs; EC. 2.5.1.18) are a large family of multifunctional enzymes that play crucial roles in the metabolism and inactivation of a broad range of xenobiotic compounds. In the present work, we report the kinetic and structural characterization of the isoenzyme GSTM1-1 from Camelus dromedarius (CdGSTM1-1). The CdGSΤM1-1 was expressed in E. coli BL21 (DE3) and was purified by affinity chromatography. Kinetics analysis showed that the enzyme displays a relative narrow substrate specificity and restricted ability to bind xenobiotic compounds. The crystal structures of CdGSΤM1-1 were determined by X-ray crystallography in complex with the substrate (GSH) or the reaction product (S-p-nitrobenzyl-GSH), providing snapshots of the induced-fit catalytic mechanism. The thermodynamic stability of CdGSTM1-1 was investigated using differential scanning fluorimetry (DSF) in the absence and in presence of GSH and S-p-nitrobenzyl-GSH and revealed that the enzyme’s structure is significantly stabilized by its ligands. The results of the present study advance the understanding of camelid GST detoxification mechanisms and their contribution to abiotic stress adaptation in harsh desert conditions.

Evaluating the distribution of T-lymphocytes and S-phase proliferating cells across the nasal mucosa of dromedary camel (Camelus dromedarius)

The lining mucosa of the nasal cavity performs important roles for the host adaptation to the external environment. Camels are unique in their adaptation to the lifestyle of nomadic deserts. The present study aimed to evaluate the distribution pattern of T lymphocytes and S-phase proliferating cells within the nasal mucosa of camel using antibodies against CD3 and PCNA, respectively. The mucosa of the rostral, middle, and caudal parts of the nasal cavity was collected and processed for immunohistochemical staining. CD3-immunoreactive (-IR) cells were observed within the epithelium and lamina propria of all examined parts. However, the numbers of these cells were significantly higher in the rostral part of the nasal mucosa compared to its middle and caudal parts (P < 0.05). Such expression of CD3-IR cells within the rostral nasal mucosa was most pronounced within its lamina propria which also revealed aggregations of lymphoid cells. The increased frequency of CD3 expressing cells at the rostral part of the nasal mucosa suggests a potential role of the nasal vestibule in limiting the infection via constant clearance of encountered pathogens. PCNA-IR cells were mainly found within the basal layers of the nasal epithelium at the rostral part of the nasal cavity, though they showed a significant decrease in their frequencies on moving caudad. The results of the present work will form a basis for assessment of various nasal pathologies affecting camels particularly those associated with increased rates of T lymphocytes infiltration and/or cell proliferation.