Browsing by Subject "TEM"

Now showing 1 - 4 of 4
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    Imagen MET 01
    (Edit.UM. Ediciones de la Universidad de Murcia, 2022) Ubero Pascal, Nicolás; Departamento de Zoología y Antropología Física
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    Microscopic studies on the structure of microornamentation and adhesive setae in normal and regenerating tail scales of some geckos
    (2026) Lorenzo Alibardi; Antonio Bonfitto; Biología Celular e Histología; Universidad de Murcia, Departamento de Biologia Celular e Histiologia
    The present review summarizes recent information on the formation and fine structure of epidermal microornamentation and adhesive setae in scale pads of the tail in some arboreal geckos. The study utilizes transmission and scanning electron microscopy, in conjunction with immunolabeling, to detect the main proteins of the microornamentation, known as Corneous Beta Proteins. These are special small proteins with a central region containing beta-sheets that form most of the corneous material of scales and pads. These proteins are packed into long cords that form short spinulae or longer setae. In tail scales, the spinulae feature different shapes but possess a limited size, 0.5-2.0 µm. In sparse areas located toward the distal part of the tail, some scales form adhesive pads, and their microornamentation grows longer, forming setae of 10-30 µm in length in the species studied herein. This process gives rise to stiff but flexible bristles that arboreal geckos use for adhesion on vertical or inverted substrates or tree branches. During tail regeneration, some scales also regenerate the adhesive setae and give rise to new adhesive pads. Caudal setae are formed by a process similar to that observed during the formation of digital setae. This derives from the interaction of a specific epidermal layer (clear) with another layer (Oberhäutchen), which are formed in the scale pads. Setae vary in length, diameter, or terminal arborization, and they resemble those of the digits, albeit shorter. The presence of caudal adhesive pads reinforces the prehensibility and maneuverability of these arboreal lizards in their environment.
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    Ultrastructural changes of the human enteric nervous system and interstitial cells of Cajal in diverticular disease.
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Alaburda, Paulius; Lukosiene, Jaune I.; Pauza, Audrys G.; Kyguoliene, Kristina Rysevaite; Kupcinskas, Juozas; Saladzinskas, Zilvinas; Pauziene, Neringa
    Background. In spite of numerous advances in understanding diverticular disease, its pathogenesis remains one of the main problems to be solved. We aimed to investigate the ultrastructural changes of the enteric nervous system in unaffected individuals, in asymptomatic patients with diverticulosis and in patients with diverticular disease. Methods. Transmission electron microscopy was used to analyse samples of the myenteric, outer submucosal and inner submucosal plexuses from patients without diverticula (n=9), asymptomatic patients with diverticulosis (n=7) and in patients with complicated diverticular disease (n=9). We described the structure of ganglia, interstitial cells of Cajal and enteric nerves, as well as their relationship with each other. The distribution and size of nerve processes were analysed quantitatively. Results. In complicated diverticular disease, neurons exhibited larger lipofuscin-like inclusions, their membranous organelles had larger cisterns and the nucleus showed deeper indentations. Nerve remodeling occurred in every plexus, characterised by an increased percentage of swollen and fine neurites. Interstitial cells of Cajal had looser contacts with the surrounding cells and showed cytoplasmic depletion and proliferation of the rough endoplasmic reticulum. In asymptomatic patients with diverticulosis, alterations of enteric nerves and ICC were less pronounced. Conclusions. In conclusion, the present findings suggest that most ultrastructural changes of the enteric nervous system occur in complicated diverticular disease. The changes are compatible with damage to the enteric nervous system and reactive remodeling of enteric ganglia, nerves and interstitial cells of Cajal. Disrupted architecture of enteric plexuses might explain clinical and pathophysiological changes associated with diverticular disease
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    Ultrastructure and lectin cytochemistry of secretory cells in lingual glands of the Japanese quail (Coturnix coturnix japonica)
    (Murcia : F. Hernández, 2009) Capacchietti, M.; Sabbieti, M.G.; Agas, D.; Materazzi, S.; Menghi, Giovanna; Marchetti, L.
    In the present study, as continuation of our previous research, Japanese quail (Coturnix coturnix japonica) lingual glands were investigated by means of transmission electron microscopy (TEM) to understand the cytoarchitecture and the subcellular sugar distribution within the different secretory structures. Indeed, glycosidic residues were visualized by applying an indirect technique of binding and the terminal sialoglycoconjugate sequences were characterized by employing sialidase digestion combined with lectin affinity. The ultrastructural analysis revealed an unusual cytoarchitecture of the caudal portion of anterior lingual gland that was composed of both secretory cells, filled with granules, and non-secretory cells, filled with mitochondria. Conversely, the posterior lingual gland was composed of secretory units of lingual glands only containing mucous cells filled with secretory granules with a variable morphology, including bipartite features characterized by an electron-lucent matrix and one or more electron-dense areas. Actual findings further supported that the quail lingual glands produce sialoglycoconjugates characterized by a heterogeneous composition. In conclusion, the cytological characteristics and the carbohydrate composition of quail lingual glands suggest that, analogously to mammal salivary glands, avian lingual glands could also be involved in several functions that can be correlated with the occurrence of sialic acids.