A novel epidermal gland type in lizards (α-gland): structural organization, histochemistry, protein profile and phylogenetic origins

Author(s):  
André L G Carvalho ◽  
Adriana M Jeckel ◽  
Carolina Nisa ◽  
María Celeste Luna ◽  
Carla Piantoni

Abstract Chemical signalling is an essential component of the communication system of lizards, and epidermal glands are responsible for producing semiochemicals that regulate many behavioural interactions. Two types of epidermal glands have been previously described for lizards: follicular and generation glands. Generation glands are characterized by the aggregation of novel glandular cell types in the epithelium and the lack of a lumen or external pore. Despite the fact that several subtypes of generation glands have been recognized over the years, the morphology, taxonomic distribution, function and evolutionary origins of generation glands remain nearly unexplored in Neotropical clades. Here, we describe a novel escutcheon-type generation gland (‘α-gland’) for lizards of the South American family Tropiduridae, characterize its structural and ultrastructural organization, and study the homology of the constituent parts in a phylogenetic framework. The α-glands emerged in the ancestor of Eurolophosaurus, Plica, Strobilurus, Tropidurus and Uracentron, and are found in at least 39 species with diverse ecological habits. We preliminarily analysed the protein profile of α-glands and discovered differential expression of protein components between sexes. Our investigations change the general view about epidermal gland homology, leading us to argue that generation and follicular glands are possibly more closely related functionally and evolutionarily than previously thought.

1993 ◽  
Vol 71 (9) ◽  
pp. 1861-1868 ◽  
Author(s):  
F. Pardos ◽  
C. Roldán ◽  
J. Benito ◽  
A. Aguirre ◽  
I. Fernández

The lophophoral tentacles of two phoronids, Phoronis psammophila and Phoronis hippocrepia, are described from an ultrastructural point of view. The tentacles are hollow structures, with an epidermis exhibiting supporting cells, sensory cells, and four types of gland cells, A, B1, B2, B3. The epidermis rests on a connective tissue layer, tubular in shape, enclosing a coelomic space lined by myoepithelial mesothelium (peritoneum). There is a single blood capillary in the tentacular coelomic cavity, attached to the frontal face of the tentacle, with contractile walls derived from the peritoneum. Both erythrocytes and amoebocyte-like cells occur inside the capillary. Differences between the tentacles of these two species and those of Phoronis australis, whose structure is already known, mainly concern the abundance and distribution of the epidermal gland cell types and are related to the burrowing and tube-building activities of these animals in different substrata.


2021 ◽  
Author(s):  
John H. Henson ◽  
Bakary Samasa ◽  
Charles B. Shuster ◽  
Athula H. Wikramanayake

AbstractWnt/β-catenin (cWnt) signaling is a crucial regulator of development and Dishevelled (Dsh/Dvl) functions as an integral part of this pathway by linking Wnt binding to the frizzled:LRP5/6 receptor complex with β-catenin-stimulated gene expression. In many cell types Dsh has been localized to ill-defined cytoplasmic puncta, however in sea urchin eggs and embryos confocal fluorescence microscopy has shown that Dsh is localized to puncta present in a novel and development-essential vegetal cortex domain (VCD). In the present study, we used super-resolution light microscopy and platinum replica TEM to provide the first views of the ultrastructural organization of Dsh within the sea urchin VCD. 3D-SIM imaging of isolated egg cortices demonstrated the concentration gradient-like distribution of Dsh in the VCD, whereas higher resolution STED imaging revealed that some individual Dsh puncta consisted of more than one fluorescent source. Platinum replica immuno-TEM localization showed that Dsh puncta on the cytoplasmic face of the plasma membrane consisted of aggregates of pedestal-like structures each individually labeled with the C-terminus specific Dsh antibody. These aggregates were resistant to detergent extraction and treatment with drugs that disrupt actin filaments or inhibit myosin II contraction, and coexisted with the first division actomyosin contractile ring. These results confirm and extend previous studies and reveal, for the first time in any cell type, the nanoscale organization of plasma membrane tethered Dsh. Our current working hypothesis is that these Dsh pedestals represent a prepositioned scaffold organization that is important for canonical Wnt pathway activation at the sea urchin vegetal organization and may also be relevant to the submembranous Dsh puncta present in other eggs and embryos.


1988 ◽  
Vol 66 (9) ◽  
pp. 2057-2064 ◽  
Author(s):  
S. R. Gelder ◽  
J. P. Rowe

Eight types of gland cells are present in six different epidermal glands in the branchiobdellid Cambarincola fallax. The anterior and posterior adhesive organs are both composed of viscid and releaser adhesive gland cell types, and their secretions open onto the anterior attachment site on the ventral surface of the ventral peristomial lip and onto the posterior attachment disc, respectively. The secretion granules of the viscid gland cell type are composed of neutral mucosubstances with basic proteins containing arginine and (or) lysine; the releaser gland cell type contains basic proteinaceous granules with a tryptophan component. These adhesive glands are very similar to duo-gland adhesive organs described elsewhere. Use of the term "sucker" should be discontinued as there is no suctorial mechanism at the anterior attachment site and only circumstantial evidence of such action at the posterior disc. Two epidermal gland cell types occur together in groups of two to four cells at sites scattered over the body surface except in trunk segments 6 and 7. One of these epidermal gland cell types produces granular secretions formed of neutral mucosubstances with a basic protein component, and the other produces globular secretions composed of a carboxylated acid mucosubstance. Secretions from the peristomial gland cells open onto the dorsal and ventral lips. The posterolateral gland cells form three pairs: two pairs in segment 8 and one pair in segment 9. Both peristomial and posterolateral gland cells have granular secretions composed of neutral mucosubstances with a basic protein component. The two types of clitellar gland cells are arranged in groups of 7 to 13 cells with a granular secretion type predominating over one with globular secretions. The granular type consists of neutral mucosubstances with amyloid-like and strong basic protein components, and the globular type consists of a carboxylated acid mucosubstance with a nonbasic protein component.


Author(s):  
Norbert Cyran ◽  
Waltraud Klepal ◽  
Janek von Byern

Water drift and tidal rise make the use of bonding mechanisms beneficial for small benthopelagic or interstitial marine animals. Chemical adhesives for attachment are very common in molluscs; however, only a few cephalopods have glue producing organs. The family Idiosepiidae is characterized by an epithelial adhesive organ (AO) located on the posterior part of the dorsal mantle area. Previous morphological and histological studies described three non-glandular cell types (basal, interstitial and fusiform cells) and three glandular cell types (goblet, columnar and granular cells) containing protein and carbohydrate components. However, these studies provide different information about the nomenclature and characteristics of the cell types. The present ultrastructural analyses and a 3D reconstruction of the AO ofIdiosepius pygmaeusandIdiosepius biserialistherefore serve to investigate the cell distribution, the fine structure of the cells and possible interactions between the cells.We found that basal cells form a continuous cell layer along the basal membrane, overlapped by the other epithelial cells. Embedded in microvilli-covered interstitial cells the glandular cells are more or less evenly distributed within the AO. Goblet and granular cells are solitary glandular cells without conspicuous morphological characteristics, whereas the columnar cells are arranged in dense aggregations of 5–15 cells. Each columnar cell is enclosed by a narrow supporting interstitial cell which contains dense longitudinal filament strands. The secretory process of the cells in the aggregation is synchronized. Each columnar cell aggregate bears approximately two ciliated sensory fusiform cells. The fusiform cells are connected to a neuronal network, aligned along the epithelium base.The results suggest that the bonding system is affected by two secretory cell types (granular and columnar cells). Both are similar in content, synthesis and secretory process but columnar cells are embedded in a particular cell environment. It is unclear in what way this arrangement is associated with the function of the AO. The neurons in several parts of the AO point to a neuronal control of the bonding mechanism. Comparisons with the AO cells of other cephalopods provide no indications for a morphological relationship between the adhesive systems.


1991 ◽  
Vol 39 (9) ◽  
pp. 1157-1166 ◽  
Author(s):  
W B VanWinkle

As with secretory granules in other cell types, many of the protein components that make up the cytoplasmic granules of human leukocytes are glycoproteins. It is not unexpected, therefore, that lectins specific for various carbohydrate moieties can be localized in these granules following appropriate protocols for specimen preparation and thin-section labeling. In this study, isolated human eosinophils and neutrophils were prepared for lectin-gold electron microscopic localization by procedures that involve no exposure to aqueous fixatives, buffers, or solvents (rapid cryofixation and molecular distillation drying), thus removing the potential problem of constituent extraction or translocation during so-called "wet chemical" processing. In contrast to other reports, data presented illustrate the specific binding of soybean agglutinin (SBA) to eosinophil granule matrices (not the crystalline cores), as well as to a population of granules in neutrophils. A similar labeling pattern for wheat germ agglutinin (WGA) was also seen, confirming the presence of N-acetyl-D-galactosamine and N-acetyl-D-glucosamine residues in eosinophil and neutrophil granule matrices. These studies emphasize the need for carefully designed specimen preparation as well as subsequent thin-section labeling procedures in lectinocytochemical studies.


2003 ◽  
Vol 4 (5) ◽  
pp. 531-536 ◽  
Author(s):  
Ivan Lefkovits

Lymphocytes are the best-studied higher eukaryote cells. In this report, quantitative relationships of the protein components in resting cell, blast cell and plasma cell types are evaluated. The comparison of these cell types leads to the conclusion that resting cells synthesize about one-twentieth of the protein species as compared to blast cells. Blast cells seem to be metabolically the most robust lymphocyte type. Plasma cells are geared towards synthesis of one main product (antibody in B plasma cells), while most of the synthesis of other protein species (including those for housekeeping and repair) decreases as the messages decay. Although the data presented in this communication allow a meaningful comparison of three cell populations, they are far from providing a full picture. Both silver staining and radiofluorography depict only proteins of high or intermediate abundance. Silver staining misses most proteins present at <10 000 copies/cell, while radiofluorography misses all those proteins with slow turnover (and those with no methionine residue in their sequence). The detection of 1100 spots in the blast cell-related radiofluorograph includes visualization of some 97–99% of protein mass, but some 3900 polypeptide species in the remaining 1–3% of protein mass will pass undetected. This protein mass (0.7–2 pg) reflects some 2500–7500 copies of each of those 3900 polypeptide species that are present in the cell below the detection limit. The work emphasizes that full understanding of cellular function can be achieved only if quantitative aspects of cell inventory are considered.


2003 ◽  
Vol 83 (2) ◽  
pp. 581-632 ◽  
Author(s):  
Robert D. Burgoyne ◽  
Alan Morgan

Regulated exocytosis of secretory granules or dense-core granules has been examined in many well-characterized cell types including neurons, neuroendocrine, endocrine, exocrine, and hemopoietic cells and also in other less well-studied cell types. Secretory granule exocytosis occurs through mechanisms with many aspects in common with synaptic vesicle exocytosis and most likely uses the same basic protein components. Despite the widespread expression and conservation of a core exocytotic machinery, many variations occur in the control of secretory granule exocytosis that are related to the specialized physiological role of particular cell types. In this review we describe the wide range of cell types in which regulated secretory granule exocytosis occurs and assess the evidence for the expression of the conserved fusion machinery in these cells. The signals that trigger and regulate exocytosis are reviewed. Aspects of the control of exocytosis that are specific for secretory granules compared with synaptic vesicles or for particular cell types are described and compared to define the range of accessory control mechanisms that exert their effects on the core exocytotic machinery.


PROTOPLASMA ◽  
2021 ◽  
Author(s):  
T. Finkbeiner ◽  
C. Manz ◽  
M. L. Raorane ◽  
C. Metzger ◽  
L. Schmidt-Speicher ◽  
...  

AbstractPlants produce a wide variety of secondary metabolites, which often are of interest to pharmaceutical and nutraceutical industry. Plant-cell cultures allow producing these metabolites in a standardised manner, independently from various biotic and abiotic factors difficult to control during conventional cultivation. However, plant-cell fermentation proves to be very difficult, since these chemically complex compounds often result from the interaction of different biosynthetic pathways operating in different cell types. To simulate such interactions in cultured cells is a challenge. Here, we present a microfluidic bioreactor for plant-cell cultivation to mimic the cell–cell interactions occurring in real plant tissues. In a modular set-up of several microfluidic bioreactors, different cell types can connect through a flow that transports signals or metabolites from module to module. The fabrication of the chip includes hot embossing of a polycarbonate housing and subsequent integration of a porous membrane and in-plane tube fittings in a two-step ultrasonic welding process. The resulting microfluidic chip is biocompatible and transparent. Simulation of mass transfer for the nutrient sucrose predicts a sufficient nutrient supply through the membrane. We demonstrate the potential of this chip for plant cell biology in three proof-of-concept applications. First, we use the chip to show that tobacco BY-2 cells in suspension divide depending on a “quorum-sensing factor” secreted by proliferating cells. Second, we show that a combination of two Catharanthus roseus cell strains with complementary metabolic potency allows obtaining vindoline, a precursor of the anti-tumour compound vincristine. Third, we extend the approach to operationalise secretion of phytotoxins by the fungus Neofusicoccum parvum as a step towards systems to screen for interorganismal chemical signalling.


2008 ◽  
Vol 294 (1) ◽  
pp. H392-H401 ◽  
Author(s):  
Daniela Volonte ◽  
Charles F. McTiernan ◽  
Marek Drab ◽  
Michael Kasper ◽  
Ferruccio Galbiati

Caveolae are 50- to 100-nm invaginations of the plasma membrane. Caveolins are the structural protein components of caveolar membranes. The caveolin gene family is composed of three members: caveolin-1, caveolin-2, and caveolin-3. Caveolin-1 and caveolin-2 are coexpressed in many cell types, including adipocytes, endothelial cells, epithelial cells, and fibroblasts. In contrast, caveolin-3 expression is essentially restricted to skeletal and smooth muscle cells as well as cardiac myocytes. While the interaction between caveolin-1 and caveolin-2 has been documented previously, the reciprocal interaction between endogenous caveolin-1 and caveolin-3 and their functional role in cell types expressing both isoforms have yet to be identified. Here we demonstrate for the first time that caveolin-1 and caveolin-3 are coexpressed in mouse and rat cardiac myocytes of the atria but not ventricles. We also found that caveolin-1 and caveolin-3 can interact and form heterooligomeric complexes in this cell type. Doxorubicin is an effective anticancer agent, but its use is limited by the possible development of cardiotoxicity. Using caveolin-1- and caveolin-3-null mice, we show that both caveolin-1 and caveolin-3 expression are required for doxorubicin-induced apoptosis in the atria through activation of caspase 3. Together, these results bring new insight into the functional role of caveolae and suggest that caveolin-1/caveolin-3 heterooligomeric complexes may play a key role in chemotherapy-induced cardiotoxicity in the atria.


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