Morphology of the European sea bass (Dicentrarchus labrax) tongue

The European sea bass, a member of the Moronidae family, is a food fish, considered one of the first models for the intensive breeding in salt water. It has nowadays an important and increasing presence in the international fishing markets. Sea basses are carnivorous, feeding on little fishes and invertebrates. Considering the important role of the tongue during the intraoral transport and the swallowing of food, scarce data are present in literature about its morphology. The aim of this study was to analyze the morphology of the tongue by means of scanning electron and light microscopy. Adult sea basses were obtained from the aquarium of the Sicilian Center of Experimental Ichthyiopathology of the University of Messina. The fishes were anaesthetized with MS 222 and the heads were then quickly removed and processed for the paraffin embedding and SEM processing. Three different tongue regions could be distinguished: an apex, a body, and a root. Scanning electron and light microscopy showed the presence of numerous canine-like teeth, surrounded by taste buds and numerous fungiform and conical papillae. The teeth were curved and their tips were posteriorly oriented. The results confirm, in teleosts too, the fundamental role of the tongue in the mechanics of food ingestion. Moreover, the presence of taste buds demonstrates the interaction of food processing and taste. These data could be a potential source to identify new and better methods of nutrition in the breeding of this fish.     

Morphology of the tongue dorsal surface of gilthead seabream (Sparus aurata)

The gilthead seabream is a food fish, one of the most frequently used in aquaculture. In the species of commercial interest, feeding in captivity is very important and this process is strictly related to the morphological characteristics of the oral cavity. The aim of this study is, using the standard procedures for light and scanning electron microscopy, to analyze the morphology of the tongue dorsal surface to show if relationships are present between the tongue morphology and the nutritional habits and choices of this farmed species. The main characteristic of the gilthead seabream oral cavity floor is the presence of an apical pouch, with, probably, a protective role mainly for the apical, free part of the tongue. Three zones, like in other teleosts, an apex, a body and a root, can be clearly distinguished. In the pouch foliate‐like papillae were observed, while the whole tongue is characterized by the presence of two types of papillae, respectively with a fungiform and cylindroid aspect, both randomly distributed throughout the whole dorsal surface of the tongue. Scattered and numerous taste buds, with the typical pear‐onion shape, together with small and numerous taste pores are also present, distributed throughout the tongue surface. Our results demonstrate that in the gilthead seabream important mechanic and sensory roles are carried out by specific anatomical structures. Our anatomical data could give, together with further biochemical and physiological data, an important support with the aim of improving the nutrition of aquaculture species. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.     

Scanning electron microscopic and histological studies of the buccal cavity of a phytoplanktivorous small freshwater fish,Amblypharyngodon mola

The electron microscopic and histological studies of the buccal‐cavity of herbivorous fish Mola (Amblypharyngodon mola) were performed. The studies revealed that the architectures of the buccal cavity of A. mola support the herbivory nature of the fish. Both the upper and lower jaws of the fish are rich in mucus glands, unculi, and microridges. The presence of papillae like taste buds in the lower jaw of A. mola indicates the mechanosensory role of the lower jaw during gustation. These features directly support a gustatory feeding behavior associated with filter feeding in this small freshwater fish.     

Surface ultrastructure of gills in relation to the feeding ecology of an angler catfish Chaca chaca (Siluriformes,Chacidae)

Surface ultrastructure of the gills of the angler catfish Chaca chaca was investigated to unravel the adaptive modifications associated with the feeding ecology of the fish. The fish is often found in mud or in soft substrates where they remain buried both for protection and to feed. Gill rakers present on the gill arch in most fish species are absent in this fish. The absence of gill rakers are associated with the feeding habit of the fish and is considered to facilitate the swallowing of captured prey smoothly without any hindrance. Highly corrugated surface of the gill arch and gill filaments could be associated to retain water/mucus to prevent dessicassion of the fish. Papillae like epithelial protuberances each bearing a taste bud at its summit toward the pharyngeal side of the gill arch is associated with the sorting of the food. Large number of mucous goblet cells on the gill arch epithelium are considered to secret copious mucus to lubricate the prey for easy swallowing. In C. chaca the gill septa between gill filaments are reduced. This could enhance the flexibility and permit the free movement of the gill filaments. Extensive secondary lamellae and infrequent mucous goblet cells on secondary lamellae are associated to increase the surface area to enhance efficiency of gaseous exchange.     

Scanning electron microscopy and histomorphology of the epiglottis in dromedaries: A study revealing unusual structure with the probable functional role

While epiglottis is essentially a mammalian structure, studying its microstructure in any placental model will add an important information to the field of comparative anatomy and the related branches of biology. The aim of this study was to describe the structure of the epiglottis in dromedary camels using light and scanning electron microscopy (SEM), with reference to the possible functions. A total of 11 epiglottis cartilages from 11 larynges were used. The study revealed unusual, deeply situated glands just beneath the cartilage plate. They have unusually, wide surface‐openings, while their ducts were partly located within the cartilage. This is presumed to be an adaptation to the need for rapid and efficient mucosal surface hydration in the arid conditions. The possible secretion transport mechanisms in these glands were also discussed. Furthermore, the SEM revealed for the first time, the presence of taste buds in camel epiglottis. However, in histological sections, visibility of taste buds was dependent upon the staining techniques. The taste buds were not seen with standard H& E stain, as they blended imperceptibly with the surrounding epithelium. Conversely, Mallory's trichrome showed contrasting colors, and taste buds were visible. In conclusion, camel epiglottis has an unusual structure, which may be correlated to environmental adaptation and important for the general health of upper respiratory tract in this species.     

Immunoelectron microscopic studies on protein gene product 9.5 and calcitonin gene-related peptide in vallate taste cells and related nerves in the guinea pig

On the basis of our previous report that protein gene product 9.5 (PGP 9.5)-immunoreactive nerve fibers and taste cells and calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers are found in guinea pig vallate papillae [Huang and Lu (1996b) Arch. Histol. Cytol. 59:433-441]. We speculated that PGP 9.5 might be a marker for taste receptor cells and that CGRP might play an important role in taste transmission. We, therefore, performed an immunohistochemical and ultrastructural analysis of taste cells and related nerves in guinea pig vallate papillae. In the connective tissue of the vallate papilla, the ultrastructural data revealed that the PGP 9.5-immunoreactive nerve fibers were both myelinated and unmyelinated. The CGRP-immunoreactive nerve fibers were unmyelinated and surrounded by the cytoplasm of Schwann cells as were the non-immunoreactive fibers. In the vallate taste buds, only type III cells, which make synaptic contacts with intragemmal nerves, were PGP 9.5-immunoreactive, while the nerve terminals making synaptic contact with the underlying type III cells were CGRP-immunoreactive. From these observations, we conclude that: (1) PGP 9.5 might be a useful specific marker for type III cells in guinea pig vallate taste buds; and (2) CGRP-containing nerve fibers might be primarily involved in the neural transmission of taste stimuli.     

Morphological characterization of the oral cavity of the gilthead seabream (Sparus aurata) with emphasis on the teeth‐age adaptation

Gilthead sea bream with different age groups that collected from Seawater fisheries, Ismailia Governorate, Egypt, were examined by gross anatomy and scanning electron microscopy to assess the morphological characteristics of the oral cavity. Teeth patterns showed that the gilthead sea bream is adapted to the feeding pattern according to age development, as it modified from spiny form teeth in young fishes to obelisk‐like teeth and flat dome‐like teeth in growing fishes, with differentiation of teeth into three pairs of canine and conical teeth, that later differentiated to small and large flat teeth. With development, the apical pouch also showed morphological differentiation from curve‐like in small fishes to Y‐letter shape in medium‐sized fishes, which later grow to completely covering the lower jaw in grown adult fishes. Tongue papillae, on the other hand, showed some differentiation being smoother in growing fishes than adult ones. Consistent with development differentiation, the palatine region of young fishes appeared separated from the palate by deep palatine fissure, while that the same palatine region was continuous with the palate with a remnant of palatine fissure as shallow groove was noticed in grown big fishes. Taste buds were characterized in the oral cavity of small and large fishes however in large fishes; the taste buds were more prominent especially at the palate and palatine folds. These and other morphological features of the oral cavity and the feeding habits in small and large gilthead sea bream fishes were recorded. Microsc. Res. Tech. 79:227–236, 2016. © 2016 Wiley Periodicals, Inc.     

Taste characterization of orange using image processing combined with ANFIS

Alternative methods for taste evaluation of fruits are of great interest to the food industry. This paper deals with the application of ANFIS-based image processing to characterize orange taste. For this purpose, images of 300 orange samples (Bam, Khooni and Thompson varieties) were acquired using a camera and the relevant features were extracted. The features were RGB component, HSV component, texture features, major and minor diameters, area, circumference, R/G and R/B color component ratio and diameter ratio. A sensory test performed by ten panelists was used to provide the reference data for image analysis. Then, the features were entered as input to ANFIS, and taste class of the fruit was the output of ANFIS. Based on the results, the success rate for the taste classification of Bam, Khooni and Thompson orange varieties were found to be 96.6%, 93.3% and 93.3%, respectively.     

Morphological specializations of the epidermis of an angler catfish Chaca chaca (Siluriformes,Chacidae) in relation to its ecological niche: A scanning electron microscopic investigation

The present work was undertaken with the aim to deduce morphological adaptations in skin of an angler catfish Chaca chaca by means of scanning electron microscopy. The fish is nocturnal, bottom dwelling, sluggish, ambush predator, lives in sand, mud, or soft substrates often buried and camouflaged for protection and to feed. The surface of the epidermis is covered with polygonal epithelial cells, each having surface relief of microridges forming intricate patterns. In between epithelial cells irregularly distributed mucous cell openings, randomly distributed epidermal specialized structures, taste buds, and neuromasts are discernible. The epidermal specialized structures are keratinized. These are either irregularly the rounded elevated plaque like or the cone shaped structures. The superficial keratinized cells could frequently be discernible exfoliated at the surface. At intervals, characteristic epidermal projections could be observed. Surface of these projections at intervals is differentiated into short stumpy protuberances, each bearing a taste bud at its summit. Further, near the basal portion of these epidermal projections, conical, or rounded plaque like epidermal specialized structures are also discernible. The surface sculpture of the skin of Chaca chaca is associated with the structural and functional significance and physiological adaptations of the epidermis with respect to its ecological niche.     

Morphogenesis of the tongue mucosa in the domestic duck (Anas platyrhynchos f. domestica) during the late embryonic stages

The tongue in domestic duck, as in other Anseriformes, is characterized by wide variety of shape and mechanical papillae and they fulfill different function during food collection. The present work aims to describe morphological features of the tongue as well as the pace formation of the mechanical papillae during embryonic period. The results may allow to answer whether the tongue in duck is ready to fulfill feeding function after hatching. The study revealed that the particular part of the tongue and the conical papillae of the body develop between 10th and 16th day of incubation, from the caudal part of the body into the rostral part of the tongue. The conical papillae of the lingual prominence in the first row are formed from 11th to 16th day and in the second row at the turn of the 15th and 16th day of incubation. These papillae developed symmetrically from the median part of the lingual prominence, to its edges. The lingual comb, which is used during transport of the food particles, is formed between 16th and 19th day. The present study indicated the morphological changes of the particular part of the tongue and the mechanical papillae were varied between the developmental stages. The morphology of the tongue in the domestic duck is fully developed before hatching and ready to collect food by pecking and grazing. However, filter‐feeding mechanism is not still obvious. Microsc. Res. Tech. 77:667–674, 2014. © 2014 Wiley Periodicals, Inc.     

Scanning electron microscopy of the tongue papillae in the pig (Sus scrofa)

A clear understanding of the role of different papillae in the pig may permit the development of a more palatable diet, thus, better utilizing anatomical structures and morphological characteristics to enhance health and productivity in this domestic species. The study used ten healthy market-size, mixed-breed pigs to properly describe the surface structure of the tongue papillae using standard scanning electron microscopic techniques. Two types of sharp and blunt filiform papillae were identified. Fungiform papillae, located on the lateral side of the tongue, were circular and large with surface taste pores. The majority of oval papillae on the dorsal surface of the tongue contained multidirectional surface grooves and lacked taste pores. The foliate papillae, located principally on the caudal third and lateral part of the tongue, were comprised of four to five leaves and they had additional pseudopapillae. The two vallate papillae, found in the caudal third and dorsum of the tongue, had a well-defined vallum and pseudopapillae on their surface. At the root of the tongue, two types of conical papillae with or without apex were observed. The entire area covered by conical papillae was deeply occupied by lingual tonsils. The lingual tonsils were scattered with varying sized lymph nodules in the propria mucosa of the conical papillae deep to epithelium. Functionally, the filiform and conical papillae appeared to have a mechanical role whereas fungiform, foliate, and vallate papillae apparently perform a gustatory role in the pig. The tonsillar location at the root of the tongue provides an ideal experimental model for immunohistological and immunological studies on the lymphoid tissue in man.     

Functional and comparative study of lingual papillae in four species of bear (Ursidae) by scanning electron microscopy

The eight current species of bear (Ursidae) are widely distributed throughout Europe, Asia, and America. They are mainly encountered in the northern hemisphere, except for the spectacled bear and the sun bear, which are also found in the south of the equator. Adaptations of the masticatory apparatus (teeth, tongue, and musculature) to diet are one of the factors that imply the greatest structural changes in the cranium. This diet may be carnivorous, herbivorous, melliferous, or insectivorous, with one type of food predominating according to the time of year. The way in which food is eaten determines the morphology of the lingual surface; generally speaking, all bears put their mouth to the food, which, initially, they lick or they let the food stick to their tongue, as occurs when insects are eaten. As in all mammals, a distinction can be made between mechanical and gustatory papillae and the development and distribution of which depend on the species and their eating habits. In this study of the complete tongues of four species of adult bears, we describe the morphology of the lingual surfaces, the different types of papillae, their characteristics, and topographic distribution. It was seen that there were five main types of lingual papillae: filiform, conical, fungiform, foliate, and vallate. Morphology of the microgrooves and pores was similar to that observed in other mammals. In general, there were no great differences among the four species of bears studied, perhaps due to the similarity in the kind of food they consume in captivity.     

Macroscopic and microscopic analysis of the tongue of the common opossum (Didelphis marsupialis)

We performed a macroscopic and microscopic study of the tongues of common opossums, Didelphis marsupialis, from South America. We studied two males and two females. We collected morphometric data on the tongue with precision calipers. For the light microscopy and scanning electron microscopy analyses, we fixed tissue fragments in 10% formaldehyde and 2.5% glutaraldehyde, respectively. The opossum tongues averaged 5.87 ± 0.20 cm in length, 3.27 ± 0.15 cm in width at the lingual body, and 3.82 ± 0.15 cm in width at the root. The mean thickness of the lingual body was 1.8 ± 0.1 cm, and the thickness of the root was 3.82 ± 0.15 cm. Sharp filiform papillae were scattered across the entire tongue; conical filiform papillae occurred on the lingual body and tongue tip; fungiform papillae were scattered among the filiform papillae on the lingual body and tongue tip; and there were three vallate papillae at the root of the tongue. We found two strands of papillary projections in the tongue root. Despite the low variability observed in the lingual papillae, the morphological data obtained in this study may be related to the opossum's diverse food habits and the extensive geographic distribution of the species throughout America. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Digital light microscopy as a tool in toxicological evaluation of fish erythrocyte morphological abnormalities

Fish erythrocytes are very sensitive to environmental pollution because they exhibit pathological alterations before appearance of other external symptoms, may be used as reliable toxicity bioindicators. Microscopic analysis can be a useful tool in early detection of alterations in erythrocyte morphology due to different environmental stressors, and in predicting organism's possible response ways. This study aims to evaluate the toxicity of a polluted freshwater lake on the erythrocytes of crucian carp fish, Carassius carassius, using digital light microscopy (DLM). Scanning DLM micrographs revealed the presence of nuclear and cytoplasmic abnormalities like micronucleus, nuclear buds, lobed nucleus, deformed nucleus, vacuolated cytoplasm, and echinocyte in the erythrocytes of crucian carp fish from a polluted lake. The obtained results substantiate that computation of erythrocyte morphological damages as biomarkers of exposure, through digital light microscopy software, can be effectively used as a toxicological tool.     

Ultrastructure of dermal denticles in sharpnose shark (Rhizoprionodon lalandii) (Elasmobranchii,Carcharhinidae)

The presence of denticles in the external surface, oral cavity, fins, and clasper of Elasmobranchii has been widely reported. These structures, called body denticles, may be observed on the body surface of sharks. Dermal and oral denticles are made up by a basal plate that is embedded in the dermis, forming a peduncle that grows from the base to the crown. These denticles may protect the skin against abrasion, and improve hydrodynamics and gill arches function. Rhizoprionodon lalandii is a widely distributed and very common species in Brazilian coastal areas. The aims of this study was to compare the morphology of oral and body denticles of R. lalandii to understand the implications of these structures in the behavior of these animals. Morphological analysis showed that there are differences between dermal and oral denticles, which are related to their role in different body regions. Body denticles have three cusps, and well‐defined crests and ridges, and literature data suggest that suggest that hydrodynamics is their main function. Most of the oral denticles have only one cusp, and their morphology and distribution showed that their main functions are preparing food to be swallowed and protecting the oral cavity against abrasion. Microsc. Res. Tech. 78:859–864, 2015. © 2015 Wiley Periodicals, Inc.     

The development of the tongue of the domestic goose from 9th to 25th day of incubation as seen by scanning electron microscopy

The general development of the tongue in birds was described by Lillie ( 1908 ) in chicken. Bryk et al. ( 1992 ) also studied the tongue development in chicken and they observed development of the conical papillae of the body. Our study aims to describe the timing of the development of the tongue morphological features in the domestic goose by using SEM methods. The tongue of the domestic goose is characterized by the widest variety of shape of the particular part of the tongue and mechanical papillae. Results indicated that the formation of the apex, body, lingual prominence, and the root of the tongue take place between the 10th and 19th day of incubation. The tongue elongates rapidly between the 16th and 18th day of incubation. Simultaneously, the median groove appears on the body and the lingual prominence and elongates towards the rostral part of the tongue. The conical papillae of the tongue develop gradually. On the body, the conical papillae develop from the caudal part of the body to the rostral part and on the lingual prominence from the median part of the prominence to the lateral part. Hair‐like papillae at the caudal surface of the body of the tongue remain primordial to the end of the incubation. Our studies on the morphogenesis of the tongue in the domestic goose revealed changes in shape of the particular part of the tongue and rapid pace of the formation of mechanical papillae. The tongue is completely develop before hatching and ready to collect food. © Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.     

Descriptive studies on the tongue of two micro‐mammals inhabiting the Egyptian fauna; the Nile grass rat (Arvicanthis niloticus) and the Egyptian long‐eared hedgehog (Hemiechinus auritus)

The current study aimed to describe the anatomical features of the tongues of two micro‐mammals common in the Egyptian fauna; the Nile grass rat (Arvicathis niloticus), and the Egyptian long‐eared hedgehog (Hemiechinus auritus). The tongues of five adult individuals of each species were excised and processed histologically, histochemically, and morphometrically. Statistical analysis comparing the relative tongue length in both species showed that there was a significant difference, which may correlate with the difference in feeding preferences. Grossly, the Nile grass rat has a dorsal lingual prominence with bifurcated apex while, the long‐eared hedgehog has a median slight elevation with rounded apex. Numerous forms of mechanical and gustatory papillae are scattered along the lingual dorsal epithelium. The histochemical detection of keratin by Holland's trichrome stain showed an intense expression in the case of A. niloticus and mild expression in H. auritus. The framework of the tongue (entoglossum) is supported by either a core of cartilage in H. auritus or bone in A. niloticus which incorporated in the lingual root. The lingual glands also showed marked variation, the Nile grass rat exhibit dense populations of mucous‐secreting glands and lesser populations of serous‐secreting glands, the contrary is true in H. auritus. In conclusion, the micro and macro‐anatomical features of the tongues of both species showed adaptive changes to accommodate the feeding lifestyle. Such type of studies using mammals from different phylogenetic traits and almost have different feeding preferences provide answers to many research questions related to tongue evolution among mammalian vertebrates.