Morphology and ultrastructure of the mandibular gland in Camponotus japonicus.

The mandibular gland is an important exocrine gland connected to the mandibles. In ants, it plays a crucial role in alarm communication and reproduction. While the overall morphology of the mandibular gland does not vary much between ant species, significant differences exist in the ultrastructural characteristics and gland size in some reported cases. However, there have been few systematic comparative studies on this subject. In this paper, we conducted microscopic observations to analyze the morphological and ultrastructural similarities and differences of the mandibular gland in different castes of Camponotus japonicus. Our findings revealed that the mandibular glands of males were significantly larger than those of females. In terms of relative size, within the female castes the mandibular glands of minor workers were the largest. Additionally, our observations of the ultrastructure showed that secretory substances were most abundant in queens. All female castes and males showed the presence of crystalline structures in the secretory cells. The content of these biocrystals decreased from minor workers to major workers, queens, and males. In males, however, crystalline structures were rare and the most abundant substances are droplet-like secretions. The differences in morphology and ultrastructure between different castes suggest that the function of the mandibular gland varies among castes. In conclusion, our study provides insights into the morphological and ultrastructural characteristics of the mandibular gland in different castes of C. japonicus. Further research is needed to fully understand the specific functions and mechanisms of this gland in ants.

Comparative morphology and ultrastructure of the labial gland among castes of Camponotus japonicus (Hymenoptera: Formicidae).

The labial gland is a major exocrine gland in the thoracic cavity of ants, which is connected to the mouth area and opens at the base of the labium. The labial gland in the various castes and males of Camponotus japonicus were examined using dissection, light microscopy, scanning and transmission electron microscopy. Our findings reveal clear caste differences in the appearance of the labial gland, and suggest a relationship between gland structure and its behavioral role in queens, males and workers: queens possess the largest reservoir sac; males have the smallest; workers have abundant secretion droplets in the gland cells of the tubules; epithelial thickness of gland cells varies considerably between workers and reproductive ants. The apical cell region has a high density of microvilli and polymorphic mitochondria, whereas the central cell region is rich in rough endoplasmic reticulum (RER) which means its main secretions are proteinaceous compounds. We believe that the labial gland has a different function in the castes of C. japonicus: the gland of workers and queens may be used to feed the larvae; workers participate in trophallaxis in the nest, while the males are not involved in these activities. Calculations of the relative size of the labial gland for each caste and males indicated that minor workers have the relative highest developed labial gland, supporting a role in trophallaxis. In addition, we found a phenomenon of enlarged labial gland in minor workers, which accounted for almost 22%, but the reason for this is unknown.

Morphology and ultrastructure of the prepharyngeal and pharyngeal glands in the ant Camponotus japonicus.

The prepharyngeal gland (prePG) and pharyngeal gland (PG) make up the largest exocrine structures in the head of the ant Camponotus japonicus. We used microscopy to study the histological and ultrastructural features of both glands in different castes. The number of secretory units in the prePG is considerably higher than in other ant species and shows a complex duct system which is made up by duct cells, secondary ducts and a main duct. These lead the secretions of hundreds to thousands of secretory cells into the prepharynx through a modified sieve plate at each side. The glove-shaped PG shows clear caste differences in tubule number. The ultrastructure of both the prePG and PG shows abundant mitochondria and secretion vesicles. Moreover, the prePG is loaded with rough endoplasmic reticulum (RER) which means its main secretions are proteinaceous compounds, while the PG is dominated by smooth endoplasmic reticulum (SER) which means the main secretions are lipids. The morphological differences like cell number of the prePG and tubule number of the PG indicate different secretory abilities of each caste. We for the first time introduce histology-based relative size to indicate secretory activity. The proportionally high development of the prePG in minor workers supports a role in trophallaxis.

External nasal gland morphology of Eurycea bislineata (Amphibia, Urodela, Plethodontidae).

Plethodontid salamanders possess numerous courtship glands. Previous studies have shown that the glands are more prominent in male individuals than females, and often experience periods of atrophy and hypertrophy throughout the year that correlate to the nonmating and mating seasons, respectively. We sampled male and female Eurycea bislineata throughout the year to test the hypothesis that external nasal glands are courtship glands. External nasal glands are paired, branched tubular glands that extend from excretory ducts dorsal to the nares to terminal secretory units posterior to the eyes. We found that the glands hypertrophy and stain/react more intensely with histochemical procedures during the mating season. Hypertrophy of the glands is more pronounced in males, and seasonal variation in epithelial height of external nasal glands of males is significantly correlated to that of seasonal variation in mental gland epithelial height, a known courtship gland found in males, when compared throughout the year. This correlation was not as strong in females, confirming sexual dimorphism of external nasal glands in terms of seasonal variation. We found no ultrastructural differences between male and female external nasal glands. In all specimens, the glandular tubules were lined by a simple, columnar epithelium that was packed with secretory granules that often obscured other cytoplasmic contents.

Histology and ultrastructure of glands associated with the sting apparatus of the swarm-founding wasp Protopolybia exigua (Hymenoptera: Vespidae: Polistinae).

Social insects present a great diversity of exocrine glands, which are linked to fundamental roles of social life, and their morphological characterization represents the first step toward the knowledge of their function. We here describe the exocrine glands present in the sting apparatus of queens and workers of the wasp Protopolybia exigua. Histological analysis of serial sections under light microscopy revealed a glandular epithelium in the spiracular plate, the quadrate plate, and the gonostyli, while the last two in addition also contain clusters of class-3 cells. A big cluster of class-3 cells was also found in the oblong plate of some workers and queens. These findings reveal that a variety of glands, in addition to the common venom gland and Dufour gland, are present in association with the sting apparatus, of which three glands are novel reports for the exocrine repertoire of social insects. The position of the glands suggests a role in lubrication to provide mobility of the sting and venom ejection and/or participation in alarm behavior, while a function related to reproduction is also possible. The peculiar characteristics displayed by swarm-founding wasps are linked with exocrine gland secretions, making their investigation in Epiponini wasps a vast and interesting field.

The ultrastructure of the intramandibular gland in soldiers of the termite Machadotermes rigidus (Blattodea: Termitidae: Apicotermitinae).

Machadotermes is one of the basal Apicotermitinae genera, living in tropical West Africa. Old observations suggested the presence of a new gland, the intramandibular gland, in Machadotermes soldiers. Here, by combining micro-computed tomography, optical and electron microscopy, we showed that the gland exists in Machadotermes soldiers only as an active exocrine organ, consisting of numerous class III cells (bicellular units made of secretory and canal cells), within which the secretion is produced in rough endoplasmic reticulum, and modified and stored in Golgi apparatus. The final secretion is released out from the body through epicuticular canals running through the mandible cuticle to the exterior. We also studied three other Apicotermitinae, Indotermes, Duplidentitermes, and Jugositermes, in which this gland is absent. We speculate that the secretion of this gland may be used as a general protectant or antimicrobial agent. In addition, we observed that the frontal gland, a specific defensive organ in termites, is absent in Machadotermes soldiers while it is tiny in Indotermes soldiers and small in Duplidentitermes and Jugositermes soldiers. At last, we could also observe in all these species the labral, mandibular and labial glands, other exocrine glands present in all termite species studied so far.

The basitarsal sulcus gland, a novel exocrine structure in ants.

The basitarsus of the mid- and/or hindlegs of several Amblyoponinae ants shows a deep longitudinal groove or sulcus on its anterior face in workers and queens. Histological examination reveals this sulcus is associated with a conspicuous novel epithelial gland, which brings the number of exocrine glands in the legs of ants to 25. The ultrastructural characteristics of the gland show the presence of a well-developed smooth endoplasmic reticulum. This is indicative for the elaboration of a non-proteinaceous and thus possibly pheromonal secretion. Behavioural observations show that this secretion is collected by the tarsomeres and spread onto the brood and nest, suggesting a role in nestmate recognition. A similar basitarsal sulcus gland was also found in Nothomyrmecia, Paraponera and Tetraponera, which represents both a wide phylogenetic and ecological distribution, as it includes arboreal, ground-dwelling as well as subterranean taxa.

Venom Gland Mass Spectrometry Imaging of Saw-Scaled Viper, Echis carinatus sochureki, at High Lateral Resolution.

The snake venom gland is the place for the synthesis, storage, and secretion of a complex mixture of proteins and peptides, i.e., the venom. The morphology of the gland has been revealed by classical histology and microscopic studies. However, knowledge about the gland's cellular secretory and functional processes is still incomplete and has so far been neglected by the omics disciplines. We used autofocusing atmospheric-pressure matrix-assisted laser desorption/ionization (AP-SMALDI) mass spectrometry imaging (MSI) to investigate endogenous biomolecular distributions in the venom glands of the saw-scaled viper, Echis carinatus sochureki, employing different sample preparation methods. Fresh-freezing and formalin-fixation were tested for the gland to obtain intact tissue sections. Subsequently, MSI was conducted with 12 µm pixel resolution for both types of preparations, and the lateral distributions of the metabolites were identified. Experiments revealed that lipids belonging to the classes of PC, SM, PE, PS, PA, and TG are present in the venom gland. PC (32:0) and SM (36:1) were found to be specifically located in the areas where cells are present. The snake venom metalloprotease inhibitor pEKW (m/z 444.2233) was identified in the venom by top-down LC-MS/MS and localized by MALDI-MSI in the gland across secretory epithelial cells. The peptide can inhibit the venom's enzymatic activity during long-term storage within the venom gland. With a high degree of spectral similarities, we concluded that formalin-fixed tissue, in addition to its high ability to preserve tissue morphology, can be considered as an alternative method to fresh-frozen tissue in the case of lipid and peptide MS imaging in venom gland tissues.

Wax glands of the horned gall aphid, Schlechtendalia chinensis, at different stages.

The horned gall aphid, Schlechtendalia chinensis, inhabits the productive species of Chinese gallnuts, which have economic value. Aphid wax glands are crucial for the survival of the insects, since the secreted waterproofing wax is important to protect the aphids from predators, pathogens and honeydew contamination. In this study, we investigated the structure of wax glands and their role in different aphid stages using light and electron microscopy. Our results show that aphids of all stages except the newly hatched fundatrix possess six parallel dorsal lines and have a total of 56 wax gland plates. Although no wax glands occur on the dorsum of the newly hatched fundatrix (first instar), the glands do appear once a fundatrix enters the second instar. The wax gland plate is composed of 2-22 polygonal depressions, each of which corresponds to a secretory cell covered by cuticle. The wax glands of this aphid belong to the class 1 glands, which are formed by epidermal secretory cells. The structure of the wax glands varies in the different stages and these changes may be adaptive to the changeable microenvironments in which the aphids live.

The male reproductive accessory glands of the blister beetle Meloe proscarabaeus Linnaeus, 1758 (Coleoptera: Meloidae): Anatomy and ultrastructure of the cantharidin-storing organs.

Blister beetles owe their name to their ability to release cantharidin, a blistering terpene, the highest concentration of which is retained in male accessory glands. The anatomy and ultrastructure of the three pairs of male reproductive accessory glands and the glandular region of the two vasa deferentia of Meloe proscarabaeus were investigated using light, electron and ion beam microscopy. All of the mesodermal glands here analysed share a common structural organization with an outer muscular layer and an inner glandular epithelium facing a broad lumen in which the secretory products are released. Developed rough endoplasmic reticulum, Golgi systems, abundant mitochondria, numerous secretory vesicles and a microvillated apical membrane are commonly found in the cells of different glandular epithelia, suggesting that all accessory gland pairs as well as the vasa deferentia are involved in an active synthesis. Nevertheless, each pair of glands appears specialized in the production of a specific set of substances, as suggested by the peculiarities in cellular ultrastructure and by the different aspect of the secretions stored in their glandular lumen. The above cited features of male accessory glands of M. proscarabaeus are compared with those of other beetles and some hints on their potential role in producing and/or concentrating cantharidin are provided.

Novel exocrine glands in the foreleg coxae of Discothyrea ants.

Workers, queens and males of all examined Discothyrea species of the 'sauteri group', that have laterally expanded frontal lobes and well-developed antennal scrobes, are characterized by two hairy areas on the outer surface of their procoxae. Histological and ultrastructural examination of Discothyrea sauterirevealed that each of these areas is associated with a novel exocrine gland: the proximal procoxal gland is formed by a cluster of 15 round secretory cells of 34 µm with numerous mitochondria, smooth endoplasmic reticulum and Golgi apparatus.Their ducts have a diameter of 0.5-1 µm.The distal procoxal gland contains 50 secretory cells of 22 µm with numerous vacuoles and lamellar inclusions, and narrow ducts with a diameter of only 0.15-0.2 µm.The differences in ultrastructural appearance and duct diameter indicate that both glands produce a different but probably pheromonal secretion. The function of these novel procoxal glands could not yet be determined, although observation of D.sauteri workers and queens shows that they make frequent and peculiar leg movements, in which the foreleg basitarsus rubs over the coxal hairy areas. The foreleg basitarsus then rubs the ipsilateral hindleg basitarsus and antenna. As a last step of the sequence, the hindleg basitarsus strokes the gaster.In addition to the occurrence of these novel procoxal glands, histological examination of D. sauteri also revealed the presence of yet another novel but smaller procoxal base gland. Ants of the 'testacea group', that have less developed frontal lobes and no antennal scrobes, do not have procoxal hairy areas, although a distinct sculpturation with small pores may occur in the corresponding areas. The related Proceratium japonicum, that has a similar lifestyle as Discothyrea, does not have any of the procoxal glands and does not display the peculiar leg movements as reported for D. sauteri.

Glandular innovations for a tunnelling life: Silk and associated leg glands in Melissotarsus and Rhopalomastix queen and worker ants.

As in other Hymenoptera, adult ants cannot secrete silk, unlike the larvae that spin a cocoon prior to metamorphosis. Fisher and Robertson (1999) first showed the existence of a silk gland in the head of adult Melissotarsus beccarii workers, and we confirm this with detailed histology and ultrastructural comparisons of both queens and workers. This African genus exhibits extreme morphological adaptations (legs, head shape and mandibular muscles) for tunnelling behaviour inside living trees, that underlie an obligate mutualism with scale insects. Rhopalomastix is its sister genus distributed across Asia, and we show that queens and workers also have a silk gland. This lineage of minute workers relies on silk to secure their network of tunnels against other arboreal ants. We show striking differences between these genera in the anatomy and ultrastructure of the cells that secrete silk, especially numerous vacuoles and an unexpectedly branched end apparatus in Melissotarsus. Moreover, the legs of Melissotarsus are much more specialized for tunnelling, and this includes highly expanded basitarsi. The latter house the novel 'Delage-Darchen gland', and we document its anatomy and ultrastructure, suggesting a proteinaceous secretion to harden roofs made of silk combined with wood fragments. The restriction of the Delage-Darchen gland to Melissotarsus, combined with a modified silk gland (an almost three-fold increase in the number of secretory cells, and ultrastructural differences suggestive of higher secretory activity), are evidence of an outstanding evolutionary divergence relative to Rhopalomastix. Synthesis of silk by adults is a significant innovation among ants, but its augmented production in Melissotarsus makes them better adapted for the hazards of arboreal life.

Ultrastructure of male Centrorhynchus globocaudatus (Acanthocephala) cement apparatus and function of cement gland secretion.

Cement glands are one of the most conspicuous and distinctive elements of taxonomic interest in male Acanthocephala. Cement glands vary in shape, number and arrangement in different classes of the taxon. The glands and their products have a fundamental role in the reproductive process. Light and electron microscopy were used to investigate the ultrastructure of the cement apparatus, which includes both cement glands and the cement reservoir, in mature males of Centrorhynchus globocaudatus (Zeder, 1800). Centrorhynchus globocaudatus is an enteric parasite of birds of prey, including Falco tinnunculus (Linnaeus, 1758) and Buteo buteo (Linnaeus, 1758) from the province of Ferrara (northern Italy). The four elongated cement glands of C. globocaudatus are situated posterior to the testes. Sections through the cement glands show each gland is surrounded by a fibrous envelope with an approximate thickness of 0.6 µm. Beneath this envelope is an outer cytoplasmic layer thickness ranging from 22 to 26 µm, which contains a number of nuclei with diameters variable from 20 to 22 µm. The cytoplasmic layer is filled with prominent free ribosomes and many mitochondria with lamellar cristae. Secretory granules, measuring from 1 to 1.3 µm in diameter, are formed within the cytoplasmic layer. The cytoplasmic layer surrounds the luminal area for storage of the cement material in each gland. Cement gland ducts arise from the gland and extend towards a common cement reservoir in close contact with the seminal vesicle and Saefftigen's pouch. Microtubules, large secretory granules and rest of undefined organelles were also observed within the cement reservoir.

The Nasal Gland in Turkeys (Meleagris gallopavo): Anatomy, Histology, and Ultrastructure.

This study provides a detailed description of the major morphoanatomic and ultrastructural features of the nasal gland in turkeys. In this avian species, nasal or salt glands are bilateral, pale pink, elongated to spindle-shaped, serous, tubuloalveolar structures, with a mean length ranging from 0.64 ± 0.15 cm in poults of 4 days of age to 2.15 ± 0.17 cm at 22 weeks. Instead of having a supraorbital location as commonly seen in waterfowl and other avian species, these glands run underneath the lacrimal, frontal, and nasal bones in turkeys. The reference point for sample collection for histologic examination is just before the rostral edge of the eyelid. Each gland adheres to the surrounding bone through a thick capsule of dense connective tissue merging with the skull periosteum. Histologically, the salt gland consists of secretory tubuloalveolar structures, lined by cuboidal epithelial cells with a central canaliculus and ducts. There are small and large ducts lined by a bilayered epithelium consisting of large apical columnar secretory cells occasionally admixed with rare cuboidal cells. These cells are periodic acid Schiff negative and slightly Alcian blue positive. Both alveolar and secretory ductal cells contain slightly electrondense granular vesicles, highly folded lateral surfaces, and large numbers of mitochondria, characteristic of ion-transporting epithelia. This study provides valuable information for the accurate identification and localization of the nasal gland during necropsy, as well as its correct histologic interpretation, ultimately improving our understanding of the role of this gland in the pathophysiology of specific diseases in turkeys.

La glándula nasal en pavos (Meleagris gallopavo): Anatomía, histología y ultraestructura Este estudio proporciona una descripción detallada de las principales características morfo-anatómicas y ultraestructurales de la glándula nasal en pavos. En esta especie aviar, las glándulas nasales o glándulas salinas son estructuras bilaterales, tubuloalveolares de color rosa pálido, alargadas y serosas, con una longitud media que varía de 0.64 ± 0.15 centímetros en los pavipollos de 4 días de edad hasta 2.15 ± 0.17 centímetros en aves a las 22 semanas. En lugar de tener una ubicación supraorbital como se ve comúnmente en las aves acuáticas y otras especies de aves, estas glándulas corren por debajo de los huesos lagrimales, frontales y nasales en los pavos. El punto de referencia para la recolección de muestras para el examen histológico es justo antes del borde rostral del párpado. Cada glándula se adhiere al hueso circundante a través de una gruesa cápsula de tejido conectivo denso que se fusiona con el periostio del cráneo. Histológicamente, la glándula salina consiste en estructuras tubulo-alveolares secretoras, revestidas por células epiteliales cuboidales con un canalículo central y conductos. Hay conductos pequeños y grandes revestidos por un epitelio de dos capas que consiste en grandes células secretoras columnares apicales ocasionalmente mezcladas con escasas células cuboidales. Estas células son ácido periódico de Schiff negativas y ligeramente positivas para el azul de alcián. Las células ductales alveolares y secretoras contienen vesículas granulares ligeramente electrondensas, superficies laterales altamente plegadas y grandes cantidades de mitocondrias, características de los epitelios transportadores de iones. Este estudio proporciona información valiosa para la identificación y localización exacta de la glándula nasal durante la necropsia, así como su correcta interpretación histológica, mejorando en última instancia nuestra comprensión del papel de esta glándula en la fisiopatología de enfermedades específicas en pavos.

Functional Ultrastructure of the Excretory Gland Cell in Zoonotic Anisakids (Anisakidae, Nematoda).

Excretory and secretory products are crucial for parasite infectivity and host immunomodulation, but the functioning and ultrastructure of the excretory gland cell (EC) that produces these products are still scarcely understood and described. In light of growing reports on anisakiasis cases in Europe, we aimed to characterise the EC of larval Anisakispegreffii and adult Pseudoterranovaazarasi. In the latter, EC starts 0.85 mm from the head tip, measuring 1.936 × 0.564 mm. Larval EC shows a long nucleus with thorn-like extravaginations toward the cytoplasm, numerous electron-dense and -lucent secretory granules spanning from the perinuclear to subplasmalemmal space, an elevated number of free ribosomes, small, spherical mitochondria with few cristae and a laminated matrix, small and few Golgi apparatuses, and few endoplasmic reticula, with wide cisternae complexes. Ultrastructure suggests that anaerobic glycolysis is the main metabolic pathway, obtained through nutrient endocytosis across the pseudocoelomic surface of the EC plasmalemma and its endocytic canaliculi. Thorn-like extravaginations of EC karyotheca likely mediate specific processes (Ca2+ signaling, gene expression, transport, nuclear lipid metabolism) into the extremely wide EC cytosol, enabling focal delivery of a signal to specific sites in a short time. These functional annotations of parasitic EC should help to clarify anisakiasis pathogenesis.

Behavioral and Morphological Studies of the Membranous Tergal Structure of Male Blattella germanica (Blattodea: Ectobiidae) During Courtship.

The male German cockroach Blattella germanica (L.) exhibits a characteristic courtship display by raising its wings, turning around, and exposing its tergal glands on the seventh and eighth tergites to the female. The male secretes a courtship pheromone from the tergal glands which induces a strong feeding response in the female, facilitating copulation. Upon multiple, detailed microscopic observations of the courtship display, we found that the male markedly expanded the intersegmental area between the sixth and seventh tergites, but deflated this area as soon as it perceived a tactile stimulus on its back by the female, while continuing to raise its wings and exposing the tergal glands. The intersegmental area is composed of two parts: a membranous posterior part of the sixth tergite, and the regular intertergal membrane. The membranous posterior part was found to be crescentic in shape and clearly separated from the intertergal membrane by traverse tongue-shaped plates. Scanning electron microscopic observation revealed that there were many orifices or pores in the membranous crescentic zone, and its morphological structure was clearly different from that of the intertergal membrane. Our observations suggest that the crescentic zone is likely a secretory gland that may play an important role at the beginning of the male courtship display, different from the tergal glands.

Morphology of the digestive gland of the marine panpulmonate limpet Siphonaria lessonii: A cytological, histochemical, and ultrastructural description.

The molluskan digestive gland has been widely studied and its structural and ultrastructural descriptions have allowed the understanding of its several functions. Despite siphonarids are broadly distributed around the world, morphological studies on their digestive system are poorly represented. The panpulmonate limpet Siphonaria lessonii is the most abundant gastropod and the dominant herbivore in the rocky intertidal coast of Buenos Aires. The aim of this study was to describe the morphology, histology, ultrastructure, and histochemistry of the digestive gland of this gastropod as well as the cycle of activity of digestion. For that, different histochemical techniques along with light microscopy, transmission electron microscopy, and scanning electron microscopy were employed. This study revealed a complex epithelium, composed of a simple layer with five cell types. Digestive cells and vacuolated cells are responsible for intracellular digestion and energy accumulation; basophilic cells, secrete substances that would be involved in extracellular digestion; pigmented cells might have an excretory function and thin cells would correspond to undifferentiated cells. In addition, the tubules present a changing morphology according to the digestive activity that they undergo. As S. lessonii is a grazer that feeds continuously, the cycle of activity of the digestive gland seems to be daily.

The oral gland, a new exocrine organ of termites.

Termites have a rich set of exocrine glands. These glands are located all over the body, appearing in the head, thorax, legs and abdomen. Here, we describe the oral gland, a new gland formed by no more than a few tens of Class I secretory cells. The gland is divided into two secretory regions located just behind the mouth, on the dorsal and ventral side of the pharynx, respectively. The dominant secretory organelle is a smooth endoplasmic reticulum. Secretion release is under direct control of axons located within basal invaginations of the secretory cells. The secretion is released through a modified porous cuticle located at the mouth opening. We confirmed the presence of the oral gland in workers and soldiers of several wood- and soil-feeding species of Rhinotermitidae and Termitidae, suggesting a broader distribution of the oral gland among termites. The oral gland is the smallest exocrine gland described in termites so far. We hypothesise that the oily secretion can either ease the passage of food or serve as a primer pheromone.

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.

Light and transmission electron microscopic structure of skin glands and dermal scales of a caecilian amphibian Gegeneophis ramaswamii, with a note on antimicrobial property of skin gland secretion.

Amphibian skin secretions contain a variety of bioactive compounds that are involved in diverse roles such as communication, homeostasis, defence against predators, pathogens, and so on. Especially, the caecilian amphibians possess numerous cutaneous glands that produce the secretory material, which facilitate survival in their harsh subterranean environment. Inspite of the fact that India has a fairly abundant distribution of caecilian amphibians, there has hardly been any study on their skin and its secretion. Herein, we describe, using light microscopy and electron microscopy, two types of dermal glands, mucous and granular, in Gegeneophis ramaswamii. The mucous glands are filled with mucous materials. The mucous-producing cells are located near the periphery. The granular glands are surrounded by myoepithelial cells. A large number of granules of different sizes are present in the lumen of the granular gland. The granule-producing cells are present near the myoepithelial lining of the gland. There are small flat disk-like dermal scales in pockets in the transverse ridges of the posterior region of the body. Each pocket contains 1-4 scales of various sizes. Scanning electron microscopic (SEM) study of the skin surface showed numerous funnel-shaped glandular openings. The antibacterial activity of the skin secretions was revealed in the test against Escherichia coli, Klebsiella pneumoniae, and Aeromonas hydrophila, all gram-negative bacteria. SEM analyses confirm the membrane damage in bacterial cells on exposure to skin secretions of G. ramaswamii.