Epidermal ultrastructure of the southern right whale calf (Eubalaena australis).
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Abstract:
An ultrastructural analysis by transmission and scanning electron microscopy was carried out on normal epidermis of six southern right whale (Eubalaena australis) calves which stranded over a period of several months at Peninsula Valdes, Argentina. This was undertaken to 1) provide the first normal skin ultrastructural data on this highly endangered species which is known to display skin pathology in some instances, and 2) to elucidate further the integumentary specializations which have developed in diving marine mammals. Southern right whale lipokeratinocytes demonstrated parakeratosis and numerous intracellular lipid bodies, keratin and melanosomes, as reported for other cetacean species, but showed several unique ultrastructural features as well. These included a high prevalence of intranuclear inclusion bodies resembling small fragments of cytoplasmic keratin, and close structural relationship between cytoplasmic lipid droplets and the nucleus. The subcellular morphology supported the concept of possible nuclear import of cytoplasmic keratin and lipid metabolites through enlargements of the nuclear pore complex or other disruptions of the nuclear envelope. The light microscopy and scanning electron microscopy also revealed an irregular contour of the lipokeratinocytes which comprised the thick stratum externum, and surface flaking of the outermost cells which were covered by stubby microvillous-like remnants of intercellular junctions. These results thus suggest that the long-tem aquatic evolution of this cetacean species has resulted in a number of integumentary specializations and that investigation of their submicroscopic cytology may help elucidate the general cell biology of nuclear-cytoplasmic interactions.Keywords:
Integumentary system
Right whale
Parakeratosis
Melanosome
Epidermis (zoology)
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Little is known about the skin structure of juvenile chameleon especially its sensory function of their integumentary structure. Fifteen juvenile Chameleo chameleon are collected from Abu Rawash, Northern area of Giza, Egypt during Summer of 2015. It is belong to the order Squamata, family, Chamaeleonidae. Three ages are used in the present study and categorized according to the morphological criteria of head, abdomen and limb lengths. Dorsal abdominal surfaces are covered with abdominal scales of varying sizes either conical or elliptical-structures, regularly arranged in rows and imbricated with each other. Each scale possessed one cylindrical lenticular epidermal sense organ containing heavy sensillia. Histologically, the scales are characterized by wider conical surfaces and intermingled with another one by hinge region. The epidermal layer of outer scale surface is composed of five-layered stratified squamous epithelium including the stratum germinativum, intermediate zone of stratum spinosum and granulosum, α-keratin layer, β-keratin layer and outer superficial Oberhaütchen. Melanosomes are abundant in the intermediate zone as well as in the peripheral dermal layer underneath stratum germinativum layer. The melanosomes possessed long cellular processes with their content of melanin granules underneath the epidermis. The dermis is composed of upper collagenous and inner compact layer. Semithin sections revealed the presence of fibroblast cells, collagenous fibrils, nerve axons, melanosomes and mast cells in the connective tissue core. Increased immunoreaction of cytokeratin is observed in the epidermal layers of G3; meanwhile, an increased proliferation of epidermal and dermal cells was detected in G1. Transmission electron microscopy exhibited striking formation of dermal sense organs containing neuronal cells of both oligodendrocytes and Schwann cells with myelinated and unmyelinated nerve axons ensheathed externally by thin collagenous fibers. Finally, the author concluded that the juvenile chameleon skin is keratinized with obvious external and internal sensation and abundant mast cells within dermis giving characteristic immunity. The melanosomes are dispersed within epidermis and dermis allowing the animal to maintain its color alterations according to the surrounding environment.
Stratum spinosum
Stratum granulosum
Integumentary system
Epidermis (zoology)
Melanosome
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An ultrastructural analysis by transmission and scanning electron microscopy was carried out on normal epidermis of six southern right whale (Eubalaena australis) calves which stranded over a period of several months at Peninsula Valdes, Argentina. This was undertaken to 1) provide the first normal skin ultrastructural data on this highly endangered species which is known to display skin pathology in some instances, and 2) to elucidate further the integumentary specializations which have developed in diving marine mammals. Southern right whale lipokeratinocytes demonstrated parakeratosis and numerous intracellular lipid bodies, keratin and melanosomes, as reported for other cetacean species, but showed several unique ultrastructural features as well. These included a high prevalence of intranuclear inclusion bodies resembling small fragments of cytoplasmic keratin, and close structural relationship between cytoplasmic lipid droplets and the nucleus. The subcellular morphology supported the concept of possible nuclear import of cytoplasmic keratin and lipid metabolites through enlargements of the nuclear pore complex or other disruptions of the nuclear envelope. The light microscopy and scanning electron microscopy also revealed an irregular contour of the lipokeratinocytes which comprised the thick stratum externum, and surface flaking of the outermost cells which were covered by stubby microvillous-like remnants of intercellular junctions. These results thus suggest that the long-tem aquatic evolution of this cetacean species has resulted in a number of integumentary specializations and that investigation of their submicroscopic cytology may help elucidate the general cell biology of nuclear-cytoplasmic interactions.
Integumentary system
Right whale
Parakeratosis
Melanosome
Epidermis (zoology)
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Stratum spinosum
Epidermis (zoology)
Melanosome
Organelle
Reticular connective tissue
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An ultrastructural investigation was carried out on the cuticle, epidermis, and sensory cells in the priapulid Meiopriapulus fijiensis. Whereas the ultrastructure of the cuticle of the mouth cone and introvert principally corresponds to that of other priapulids, the cuticle of the trunk region is composed of fibrils embedded in a light matrix, has a surface characterized by densely-arranged protrusions and shows similarities to the cuticle of annelids. The epidermis is characterized by a hitherto unknown system of irregularly anastomosing channels running along the anterior-posterior axis. Integumentary structures specialized as sensilla include the first three rows of scalids on the introvert, flosculi, trunk scalids, setae, and tubules on the anal hooks. Non-sensory cuticular structures include the teeth on the mouth cone, locomotory scalids, tubercles of the general body surface, and anal hooks.
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Epidermis (zoology)
Parakeratosis
Loricrin
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Abstract The cuticle of late parasitic stages of Paragordius varius (Leidy, 1851) is composed of a layer with large fibres and a second layer (often named the areolar layer) distal from it. In this paper, organs are described that start at the basal side of the epidermis, pass the epidermis and the fibrous layer of the cuticle and merge with large, cushion‐like structures in the distal layer of the cuticle. The epidermal part of the organs is composed of darkly stained cells, which are probably in contact with the basi‐epidermal nervous system. Up to four processes of this cell traverse the cuticle. These processes might include cilia, because they contain microtubule‐like structures. The probable connection to nerve cells and the connection to the cushion‐like structures in the outer cuticular layer make it likely that the organs described here are sensory in function.
Epidermis (zoology)
Cuticle (hair)
Arthropod cuticle
Integumentary system
Granular layer
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Ultrastructural contributions to the identification of cell types in the lizard epidermal generation
Abstract The ultrastructure of the epidermis at different stages of the shedding cycle has been studied in Anolis carolinensis. Cells of the germinal layer are morphologically similar at all stages in the cycle. Immediately after leaving the germinal layer all daughter cells resemble one another closely. However, they later acquire specific ultrastructural features that enable them to be classified into six distinct fully differentiated types corresponding to the grouping previously set forth by light microscopy. A comparison of cytoplasmic filament size with the known X‐ray diffraction data suggests that the Oberhautchen and β‐layer contain a protein similar to that of avian feather; the protein in the α‐layer and lacunar tissue is similar to that in mammalian hair, and the mesos layer cells probably contain a mixture of feather and hair‐like proteins. The nature of the amorphous cytoplasmic material in the mature clear layer is as yet unknown.
Anolis
Epidermis (zoology)
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Syncytium
Primordium
Epidermis (zoology)
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Knowledge on the morphology of the cycliophoran female has mostly been based on observations of immature females in brood chambers of feeding stages. With the use of light- and transmission electron microscopy, the morphology and ultrastructure of the free and fully mature female of Cycliophora is described now for the first time. The external morphology is characterized by a ciliation consisting of an anteroventral ciliated field, a posterior ciliated tuft, and four sensory structures extending anteriorly from the anteroventral ciliated field. In addition, a small ciliated structure in the midventral region is interpreted as a round-shaped gonopore. Internally, a bilateral cerebral ganglion is situated in the anterior region and a large oocyte is located medially in the body. Several glands are present anteriorly, while posteriorly a pair of glands is associated with the ciliated tuft. Dorsal and ventral longitudinal muscles, as well as, dorsoventral muscles are identified by electron microscopy. Muscle fibers attach to the endocuticle via the epidermis, by means of attachment fibers. An unknown endosymbiont is present throughout the body of the female. We discuss the functional implications of the morphological and ultrastructural aspects of the cycliophoran female. Finally, we compare this life cycle stage with that fromother phyla, suggested as phylogenetically close.
Morphology
Tuft
Integumentary system
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This investigation examined primarily epidermal specializations of the adult horse tongue by light, scanning and transmission electron microscopy. Samples were collected from seven regions of the normal tongue of various breeds of horse. The filiform papillae, present on the dorsal and lateral aspects but not the ventral aspect of the tongue, were short, slender and finger-like structures with variable-shaped terminae. The epidermal thickness and height of dermal ridges were reduced on fungiform and vallate papillae, but tissue architecture and keratinocyte ultrastructure of most of the lingual epidermis corresponded to the common mammalian epidermal paradigm. One unique finding was the highly localized clustering of epidermal cells with exceptionally high content of PAS-negative trichohyalin cytoplasmic granules at a location atop the dermal ridges and beneath the base of filiform papillae. These granular cells were immediately subjacent to clusters of clear, non-granulated epidermal cells. It is believed that this integumentary specialization may enhance the structural strength at this localized site of the tissue architecture, in relationship to the mechanical papillae.
Integumentary system
Epidermis (zoology)
Lingual papilla
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