Structural and functional adaptation of the lingual papillae of the Egyptian fruit bat (Rousettus aegyptiacus): specific adaptive feeding strategies.

BACKGROUND: The current investigation was aimed to clarify the correlations between the feeding strategy and lingual structure of the Egyptian fruit bat captured from the Egyptian east desert. MATERIALS AND METHODS: The current work was performed on 12 adult Egyptian fruit bats that were observed grossly and with the help of the stereo, light, and scanning electron microscope. There were three types of the lingual papillae: one mechanical (filiform) and two gustatory (fungiform and circumvallate). RESULTS: There were seven subtypes of filiform papillae recognised on the seven lingual regions. There were few fungiform papillae distributed among the filiform papillae on the lingual tip and two lateral parts of apex and body while fungiform papillae were completely absent in the median part. There were three circumvallate papillae. The central bulb of circumvallate papillae was surrounded by one layer of two segmented circular pad. The lingual tip had cornflower-like and diamond-shaped filiform papillae. CONCLUSIONS: Histochemical results revealed that the lingual glands showed a stronger Alcian Blue (AB)-positive reaction and gave dark blue colour, while the reaction for the periodic acid-Schiff (PAS)-stain was negative. Also, the glands exhibited a blue colour as an indication of positive AB reactivity with combined AB-PAS staining.

Ocular morphology of the fruit bat, Eidolon helvum, and the optical role of the choroidal papillae in the megachiropteran eye: a novel insight.

BACKGROUND: This work was designed to provide a morphologic, morphometric and histochemical description of the eye of the African straw-coloured fruit bat (Eidolon helvum). An explanation of the optical role of the choroidal papillae in the vision of megachiropteran bats was provided. MATERIALS AND METHODS: Enucleated eyes of captured fruit bats were measured and processed for light microscopy. RESULTS: Typical gross features of the mammalian eye including an anterior transparent cornea, posterior whitish sclera and a golden-brown iris surrounding a round pupil were observed in the eye. Presence of undulating retina typically found in megachiropterans was also seen. The ratio of mean corneal diameter to mean axial eye diameter was 0.58 ± 0.08. The histochemical investigation of the eye indicated the presence of mucins, proteoglycans, hyaluronic acid, glycogen and/or glycoproteins in the corneal, scleral, choroidal and retinal tissues. CONCLUSIONS: The presence of reflective materials of the tapetum lucidum on the undulating retina was shown to be a morphological adaptation for increased light sensitivity as each parabolic surface of the choroidal papillae served as a convex mirror, reflecting the light rays to the adjacent parabolic surface, thus sensitising photoreceptors in affected regions. This phenomenon thus empowers megachiropteran bats with improved scotopic visual capability and could explain why most of them are reliant on their vison without the need for echolocation.

Ultrastructural features on the oral cavity floor (tongue, sublingual caruncle) of the Egyptian water buffalo (Bubalus bubalis): gross, histology and scanning electron microscope.

BACKGROUND: The present work was focused on the evaluation of morphological characteristics of the lingual caruncles and tongue with its papillae of Egyptian water buffalo (Bubalus bubalis) using gross examination, light and scanning electron microscopy. MATERIALS AND METHODS: The ventral surface of the sublingual caruncle carried a small opening of the duct of both monostomatic and mandibular salivary gland. The lingual mucosa of dorsal, lateral border and, to some extent, of ventral surface of apex had lingual papillae (filiform, fungiform), while the lingual mucosa of the lingual body especially at torus linguae had conical papillae, but circumvallate papillae observed at the caudal part of body and root. The dorsal surface of the apex and body carried numerous long, thread-like, with blunt apex, caudally directed filiform papillae that covered with keratinised scales without secondary papillae. RESULTS: The degree of keratinisation classified filiform papillae into rostral part of high keratinisation and caudal of less keratinisation. Conical papillary surface carried exfoliated epithelium with longitudinal groove on its rostral surface and carried secondary papillae. Fungiform papillae were scattered among filiform papillae on the dorsal and ventral surface of the apex and its convex surface had exfoliated keratinised epithelium. Circumvallate papillae were surrounded by circular deep groove bordered by vallum that carried small secondary papillae that ended into the primary groove. Taste buds of circumvallate papillae opened in the lateral lining epithelium facing the groove. CONCLUSIONS: Von Ebner's glands were observed in computed tomography under papillae especially toward the groove and their ducts open into the base of the groove.

Morphology of the lips, cheeks, and the hard palate of the Egyptian water buffalo (Bubalus bubalis): a focus on histological, histochemical, and ultrastructural aspects.

BACKGROUND: The available data is scanty about Egyptian water buffalo lips, cheeks, and palate. AIMS: The current investigation was focused on describing the morphology of the lip, cheek, and palate. METHODS: Our study included the gross, light, and electron microscopic examinations of ten heads of the Egyptian water buffalos. RESULTS: The nasolabial plate surface carried numerous scales of keratinized epithelium. Internal labial surface and labial mucocutaneous junctions were covered with stratified squamous keratinized epithelium. Two types of hair follicles in the dermis included ordinary and cavernous types characterized by cavernous space. The conical papillae on the internal aspect of the oral commissure were projected from the mucous membrane. Seromucous glands were occasionally observed under the oral mucous membrane of the commissure and gave positive PAS and AB. Conical papillae density on the inner cheek surface had some variations: the rostral part had large papillae, while the dorsal part had numerous papillae than the ventral part, the caudal part had a smaller number of papillae, while the middle part was devoid of papillae. Parotid duct opening in the buccal vestibule was without papillae. Conical papillae had two surfaces; the rostral surface was highly keratinized than the caudal one. The buccal gland was a compound tubuloacinar mixed (mucoserous) gland and mucus acini only reacted to PAS and AB. The oral surface of palatine rugae was covered with highly keratinized epithelium than the aboral surface. Palatine glands showed PAS and AB positive. CONCLUSION: The result describes the relationship between the available food particles, environmental conditions and the lip, cheek, and palate appearance, and structure.