Histochemical and Ultrastructural Characterization of the Posterior Esophagus of Bulla striata (Mollusca, Opisthobranchia)

2010 ◽  
Vol 16 (6) ◽  
pp. 688-698 ◽  
Author(s):  
Alexandre Lobo-da-Cunha ◽  
Elsa Oliveira ◽  
Íris Ferreira ◽  
Rita Coelho ◽  
Gonçalo Calado

AbstractThe posterior esophagus of Bulla striata, running from the gizzard to the stomach, was investigated with light and electron microscopy to obtain new data for a comparative analysis of the digestive system in cephalaspidean opisthobranchs. In this species, the posterior esophagus can be divided into two regions. In the first, the epithelium is formed by columnar cells with apical microvilli embedded in a cuticle. Many epithelial and subepithelial secretory cells are present in this region. In both, electron-lucent secretory vesicles containing filaments and a peripheral round mass of secretory material fill the cytoplasm. These acid mucus-secreting cells may also contain a few dense secretory vesicles. In the second part of the posterior esophagus, the cuticle is absent and the epithelium is ciliated. In this region, epithelial cells may contain larger lipid droplets and glycogen reserves. Subepithelial secretory cells are not present, and in epithelial secretory cells the number of dense vesicles increases, but most secretory cells still contain some electron-lucent vesicles. These cells secrete a mixture of proteins and acid polysaccharides and should be considered seromucous. The secretory cells of the posterior esophagus are significantly different from those previously reported in the anterior esophagus of this herbivorous species.

2009 ◽  
Vol 15 (S3) ◽  
pp. 39-40
Author(s):  
A. Lobo-da-Cunha ◽  
I. Ferreira ◽  
G. Calado

AbstractCephalaspideans are a group of opisthobranch gastropods comprising carnivorous and herbivorous species, allowing an investigation of the relationship between these diets and the morphofunctional features of the salivary glands.In this study, the salivary glands of the carnivorous cephalaspidean Philinopsis depicta were observed by light microscopy using semithin sections and by transmission electron microscopy. A central duct runs along the length of these thin ribbon-shaped glands dividing them in two halves, each formed by a single row of tubules perpendicularly attached to the central duct. The simple epithelium of the central duct and lateral tubes contains ciliated cells and two types of secretory cells, named granular cells and cells with apical vacuole (Fig. 1). A very thin outer layer of connective tissue covers the epithelium (Fig. 1). The ciliated cells are numerous but very thin, forming small clusters between secretory cells. The nucleus, several mitochondria and a few lysosomes are located in the apical region were the cells are wider. A very thin cytoplasmic stalk reaches the base of the epithelium and contains bundles of filaments in addition to some mitochondria.


2011 ◽  
Vol 135 (4) ◽  
pp. 503-510
Author(s):  
Darcy A Kerr ◽  
Vincent A Memoli ◽  
Sara S Cathey ◽  
Brent T Harris

Abstract We report findings from an autopsy of a 45-year-old woman with the rare lysosomal storage disease mucolipidosis type III α/β. Her disease manifested most notably as multiple bone and cartilage problems with tracheal and bronchial malacia. Principal autopsy findings included gross abnormalities in bone and cartilage with corresponding microscopic cytoplasmic lysosomal granules. These cytoplasmic granules were also seen in histologic preparations of the brain, myocardium, heart valves, and fibroblasts of the liver and skin by light and electron microscopy. By electron microscopy there were scattered, diffuse vesicular cytoplasmic granules in neurons and glia and an increase in lysosomal structures with fine electron lucent granularity in the above tissue types. Our findings help elaborate current understanding of this disease and differentiate it from the mucopolysaccharidoses and related disorders. To our knowledge, this is the first report to document pathologic findings in a patient with mucolipidosis type III α/β by autopsy.


Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
PH Maxwell ◽  
DJ Ferguson ◽  
MK Osmond ◽  
CW Pugh ◽  
A Heryet ◽  
...  

We have obtained transgenic mice in which an erythropoietin-SV40 virus T antigen fusion gene is homologously recombined into the native Epo locus. This gene is expressed in a tissue-specific manner closely resembling that of the native Epo gene. Immunohistochemical detection of SV40 T antigen has been used to characterize the hepatic cell populations expressing the transgene. In mice stimulated by anaemia or hypobaric hypoxia, SV40 T antigen was demonstrated in two liver cell populations: a subset of hepatocytes and a nonparenchymal cell type. Immunohistochemical and ultrastructural characterization of these cells by light and electron microscopy showed the nonparenchymal cell type to be the Ito cells, which lie in a persinusoidal position within the space of Disse. We therefore conclude that Ito cells are the nonhepatocytic source of liver Epo production. These cells show many similarities to the Epo-producing fibroblastoid interstitial cells of the kidney.


1964 ◽  
Vol s3-105 (69) ◽  
pp. 35-47
Author(s):  
NANCY J. LANE

In Helix aspersa, the cytoplasm of the collar cells that surround the tentacular ganglion contains spheroidal granules of low electron density (α-bodies), and β-bodies that contain electron-dense vesicles within the size range of elementary neurosecretory granules. Mitochondria and lamellar Golgi complexes are also present. Mitochondria, α-bodies, fibrils, objects resembling multivesicular bodies, and moderately electrondense granules are found in the lengthy processes into which the collar cells are drawn out. One process of each bipolar collar cell seems to merge into the tentacular ganglion. This consists of neurones with processes that contain mitochondria, vesicles of various sizes, filaments, and electron-dense granules similar to elementary neurosecretory granules. The lateral cells that line the dermo-muscular sheath encasing the optic tentacles contain in their cytoplasm an endoplasmic reticulum with many ribosomes, mitochondria, Golgi complexes, and many electron-lucent globules. These globules seem to be elaborated by the lamellar Golgi bodies. There are also electron-dense inclusions, which may be lysosomes, that are scattered sparsely between the other globules and cytoplasmic components. All these structural details are similar to those found in some mucus-secreting cells. The possible nature and origin of the tentacular secretory cells are discussed.


Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
PH Maxwell ◽  
DJ Ferguson ◽  
MK Osmond ◽  
CW Pugh ◽  
A Heryet ◽  
...  

Abstract We have obtained transgenic mice in which an erythropoietin-SV40 virus T antigen fusion gene is homologously recombined into the native Epo locus. This gene is expressed in a tissue-specific manner closely resembling that of the native Epo gene. Immunohistochemical detection of SV40 T antigen has been used to characterize the hepatic cell populations expressing the transgene. In mice stimulated by anaemia or hypobaric hypoxia, SV40 T antigen was demonstrated in two liver cell populations: a subset of hepatocytes and a nonparenchymal cell type. Immunohistochemical and ultrastructural characterization of these cells by light and electron microscopy showed the nonparenchymal cell type to be the Ito cells, which lie in a persinusoidal position within the space of Disse. We therefore conclude that Ito cells are the nonhepatocytic source of liver Epo production. These cells show many similarities to the Epo-producing fibroblastoid interstitial cells of the kidney.


1968 ◽  
Vol 36 (3) ◽  
pp. 527-549 ◽  
Author(s):  
A. M. Stuart ◽  
P. Satir

The sternal gland of primitive termites of the genus Zootermopsis (Z. nevadensis or Z. angusticollus) (Hagen) seems more organized than that of higher termites, in being comprised of three cell layers. It is also studded with about 200 campaniform sensilla. Below the meshwork cuticle of the gland lies a layer of columnar epithelial cells whose apical surfaces form a brush border, and whose basal surfaces are sculptured into a basketwork into which the second layer fits. Below the brush border are small microtubule-associated pits and coated vesicles. No channels can be seen either within or, except for the sensilla, between the cells. The second cell layer probably secretes the trail-following pheromone. Numerous electron-lucent droplets and large channels containing lipid micelles are found in the cytoplasm here, but the channels cannot be traced out of the secretory layer. The third layer consists of large pyriform cells. The campaniform sensilla are composed of three cells: the sensory cell proper whose dendrite carries a modified 9 + 0 sensory process, an accessory supporting cell that secretes an electron-opaque sheath, and an enveloping cell. At the cell borders of the sensillum, regions of septate and tight junction appear. There are also septate junctions between columnar cells and possibly tight junctions between columnar and secretory cells that would open an intracellular and molecular pathway to the endocuticle. The campaniform sensilla may be part of a feedback control system that determines the amount of pheromone deposited during trail laying.


Author(s):  
Roy Skidmore

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).


Author(s):  
T. M. Weatherby ◽  
P.H. Lenz

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.


2020 ◽  
Vol 129 (2) ◽  
pp. 189
Author(s):  
Jacenir Reis dos Santos-Mallet ◽  
Simone Patrícia Carneiro Freitas ◽  
Maria Luiza Ribeiro de Oliveira ◽  
Alice Helena Ricardo-Silva ◽  
Aníbal Gil Lopes ◽  
...  

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 640
Author(s):  
Natalia R. Moyetta ◽  
Fabián O. Ramos ◽  
Jimena Leyria ◽  
Lilián E. Canavoso ◽  
Leonardo L. Fruttero

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.


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