scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE GLAND CELLS OF THE MINK ENDOMETRIUM

1963 ◽  
Vol 18 (2) ◽  
pp. 405-418 ◽  
Author(s):  
A. C. Enders ◽  
R. K. Enders ◽  
S. Schlafke

Portions of mink endometrium in delayed implantation, early postimplantation, and pseudo pregnancy were fixed in buffered osmium tetroxide with sucrose, or potassium permanganate. After rapid dehydration the portions of endometrium were embedded in either methacrylate or epoxy resin. Examination of the cells from the body of the glands of the endometrium of delayed implantation revealed the presence of prominent terminal bars, numerous secretion granules, and membrane discs in the apical region of the cell. In the supranuclear and infranuclear regions, mildly dilated cisternae of the endoplasmic reticulum were present, and in many cells unusually large mitochondria were seen. Numerous changes were noted in the gland cells of the post implantation stage. The endoplasmic reticulum in the basal region was extensively dilated, and the nuclei were situated more centrally. Giant mitochondria were no longer present. The large secretion granules were not present, but smaller granules were seen, especially in the Golgi region. Some of the Golgi cisternae were dilated and the pattern of parallel membranes was consequently less distinct. It is suggested that gland cells in the postimplantation and pseudopregnancy stages exhibit evidence of greater secretory activity than those in the delayed implantation stage.

1974 ◽  
Vol 52 (6) ◽  
pp. 695-705 ◽  
Author(s):  
Jean E. Percy

The sex-pheromone-producing gland of Choristoneura fumiferana, as in other moths, is a modified intersegmental membrane between the eighth and ninth abdominal segments. Gland cells differ from epidermal cells in unmodified intersegmental membranes in their size, shape, and structure. One to 2 days before emergence of the adult, the gland cells have few microvilli and the cytoplasm contains mainly rough endoplasmic reticulum. By 1 h before emergence, the cells have the adult characteristics. The basal region below the nucleus contains Golgi complexes, lipid droplets, glycogen deposits, and rough endoplasmic reticulum. The apical region contains many microbodies and extensive smooth tubular endoplasmic reticulum. The apical surface has numerous well-developed microvilli, each of which contains a core of smooth endoplasmic reticulum. In contrast to gland cells, unmodified epidermal cells only contain rough endoplasmic reticulum and their apical projections are small and ill-defined. Cuticle of the gland and unmodified intersegmental membrane does not change after deposition but continues to resemble that of the developing gland 1 to 2 days before emergence. Pore canals are present as gaps in the endocuticle and follow the helicoidal arrangement of the microfibrils. Near the microvilli the pore canals contain a filamentous structure which is replaced by epicuticular filaments near the first lamella of the endocuticle. Groups of epicuticular filaments terminate at an oval depression in the dense epicuticle. Each oval depression opens at the surface of the inner cuticulin. Epicuticular filaments are not the immediate precursors of the pheromone. The probable role of the epicuticular filaments in pheromone synthesis and release is discussed.


2012 ◽  
Vol 62 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Maria Izabel Camargo-Mathias ◽  
Odair Correa Bueno ◽  
Alexsandro Santana Vieira

AbstractThe metapleural gland is considered a synapomorphy of ants, and is characterized as a paired structure located at the two postlateral ends of the thorax and secretes substances capable of inhibiting and controlling fungi and bacteria in the fungus garden and inside the nest. This study was aimed at investigating if and which are the ultrastructural differences in the metapleural gland cells of workers (three castes) of Atta laevigata using transmission electron microscopy (TEM). This study revealed the presence of Golgi regions, rough endoplasmic reticulum (lamellar and vesicular shapes), smooth endoplasmic reticulum, mitochondria (elongated, round-shaped), vacuoles, secretion granules with different electron densities, and myelin figures in the cytoplasm of secretory cells, indicating that this gland produces substances composed of proteins, lipids, and polysaccharides (glycogen in major workers). Lipid droplets and secretion granules were found very near to the microvilli, especially in minor workers. The intracellular portion of canaliculi exhibited invaginations that increased the surface area and modified the secretion produced by the secretory cells. In the three castes examined, the gland exhibited a reservoir preceded by a collecting chamber, both lined by a simple squamous epithelium with a cuticular intima. Workers of the three castes of A. laevigata might be involved in the production of secretion mainly composed of proteins with antibiotic properties and, minor workers, may be responsible for producing a wider variety of secretions compared to median and major workers in the colony.


Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 287-309
Author(s):  
Bernard Maro ◽  
Martin H. Johnson ◽  
Susan J. Pickering ◽  
Daniel Louvard

The unfertilized oocyte, fertilized egg and early embryo (2-cell to 16-cell) of the mouse have been examined immunocytochemically for the distribution of antigens associated with the endoplasmic reticulum, the lysosomal and acidic vesicle fraction (100kD antigen), Golgi apparatus (135kD antigen) and coated vesicles (clathrin). The distribution of these antigens has also been examined in isolated 8-cell and 16-cell-stage blastomeres of various ages and phenotypes. Endoplasmic reticulum is detected only weakly in the oocyte and egg, but is seen abundantly at later stages both in association with the nuclear membrane and evenly distributed throughout the cytoplasm, except in regions of cell: cell apposition from which it is excluded. Intracellular clathrin is associated with the spindle in mitotic and meiotic cells. During interphase, clathrin is distributed throughout the cell until the mid-8-cell stage when it is concentrated into the apical region of the cell under the region of membrane at which a surface pole of microvilli will form subsequently. Thus, the cytoplasmic polarization of clathrin precedes overt polarization at the surface. At mitosis, the clathrin relocates to the spindle and is distributed to both daughter cells. It resumes an apical location beneath the surface pole of microvilli in polar daughter 1/16 cells, but remains dispersed in apolar daughter 1/16 cells. Both the lysosomal and Golgi antigens are distributed throughout the cytoplasm until the early 16-cell stage. In pairs of 16-cell blastomeres both antigens aggregate in a single cluster and do so whether the surface phenotype of the blastomeres is polar or apolar. The position of this cluster is not consistently related to the point of contact with the other cell in the pair but there is a suggestion that in cells with a polar surface phenotype the polar foci of Golgi/lysosomal antigens are located between the nucleus and the surface pole at earlier time points, but shift to a position between the basolateral membrane and the nucleus at the later time point. In intact 16-cell embryos also, the aggregated Golgi/lysosomal antigens of polar cells appear to localize to the basal region. The distributions of these various organelles in embryonic cells reported here show a number of differences from those reported previously for mature, differentiated cells.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2594 ◽  
Author(s):  
Lucília S. Miranda ◽  
Allen G. Collins ◽  
Yayoi M. Hirano ◽  
Claudia E. Mills ◽  
Antonio C. Marques

Comparative efforts to understand the body plan evolution of stalked jellyfishes are scarce. Most characters, and particularly internal anatomy, have neither been explored for the class Staurozoa, nor broadly applied in its taxonomy and classification. Recently, a molecular phylogenetic hypothesis was derived for Staurozoa, allowing for the first broad histological comparative study of staurozoan taxa. This study uses comparative histology to describe the body plans of nine staurozoan species, inferring functional and evolutionary aspects of internal morphology based on the current phylogeny of Staurozoa. We document rarely-studied structures, such as ostia between radial pockets, intertentacular lobules, gametoducts, pad-like adhesive structures, and white spots of nematocysts (the last four newly proposed putative synapomorphies for Staurozoa). Two different regions of nematogenesis are documented. This work falsifies the view that the peduncle region of stauromedusae only retains polypoid characters; metamorphosis from stauropolyp to stauromedusa occurs both at the apical region (calyx) and basal region (peduncle). Intertentacular lobules, observed previously in only a small number of species, are shown to be widespread. Similarly, gametoducts were documented in all analyzed genera, both in males and females, thereby elucidating gamete release. Finally, ostia connecting adjacent gastric radial pockets appear to be universal for Staurozoa. Detailed histological studies of medusozoan polyps and medusae are necessary to further understand the relationships between staurozoan features and those of other medusozoan cnidarians.


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).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kazuki Motomura ◽  
Hidenori Takeuchi ◽  
Michitaka Notaguchi ◽  
Haruna Tsuchi ◽  
Atsushi Takeda ◽  
...  

AbstractDuring the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.


Parasitology ◽  
1969 ◽  
Vol 59 (3) ◽  
pp. 505-518 ◽  
Author(s):  
R. E. Howells ◽  
D. A. Erasmus

Regional differences in the tegumentary tissue of Moniezia expansa, as revealed at the light-microscope level by histological and histochemical techniques, are described and evidence for secretory activity by the interproglottidal glands is presented.In very immature proglottides the interproglottidal glands are at the ‘precryptic’ stage. Gland cells may be differentiated from other tegumentary cells by their high RNA content and in certain gland cells the presence of an alcian blue staining material.In mature proglottides the glands consist of rosette-like clusters of cells around crypt-like intuckings of the tegument. Two types of cells are found in the gland, small alcian blue-staining cells which are most numerous in the neck region of the crypt, and larger cells, the predominant gland cells, which do not stain with alcian blue but possess non-specific esterase activity. No other tegumentary cells in Moniezia exhibit this activity. Esterase and phosphatase activity is found in the tegument and crypt of the glands and in the interproglottidal folds.The non-enzyme histochemistry confirms and extends the observations of previous workers.Cytochrome oxidase and succinic dehydrogenase were detected in the tegumentary cells and tegument. Very strong reactions were given in the neck and scolex, with a progressive diminution of activity posteriorly along the strobila. Very low activities were recorded in the tegument of the glands.


1972 ◽  
Vol 11 (3) ◽  
pp. 899-929
Author(s):  
L. H. BANNISTER

The structure of undischarged and discharged trichocysts has been examined in Paramecium caudatum, and their light-microscopic appearance compared with their fine-structural organization. In living specimens undischarged trichocysts appear to be of a single type with a unimodal variation in length about a mean of 3.7 µm. When fixed for electron microscopy or compressed beneath a coverslip many of the trichocysts expand within the cell, giving rise to a variety of different forms of lower phase density. Ultrastructurally the undischarged trichocyst consists of at least 10 different components: these include a mesh-like sheath surrounding the body of the organelle; an inner and an outer sheath enclosing the tip, the inner sheath being made up of 4 spiralling envelopes with a square net substructure, and the outer sheath being formed of a dense amorphous matrix containing longitudinal microtubules and scattered fine filaments; a boundary surface to the outer sheath; a membranous trichocyst sac the apical region of which is surrounded by a cylinder of microtubules joined to each other with dense material; and lastly, the crystalline matrix of the trichocyst body and tip. This crystalline appearance is apparently related to the presence of a loosely interwoven complex of fine filaments which form a highly regular pattern of unit structures repeating at 16-nm intervals. In extended trichocysts the 60-nm banding pattern of the body is also composed of fine filaments arranged in a different, elongated manner in 2 distinct and alternating patterns which are taken to be 2 views of the same structure. Measurements indicate that when trichocysts extend they elongate by a factor of from 6 to 8. It is proposed that the crystalline pattern of the unextended trichocyst body transforms into the extended form by a simple rearrangement of the constituent filaments accompanied by their elongation. Possible models of the undischarged and discharged states of organization are suggested.


1962 ◽  
Vol 14 (3) ◽  
pp. 401-420 ◽  
Author(s):  
I. K. Buckley

Unfixed, compressed acinar cells of rat pancreas, isolated by mechanical and enzymatic means, were examined by phase microscopy and photomicrographed using 35 mm film and electronic flash illumination. Similarly, observations were made on Walker carcinoma cells; in addition, these cells were treated with solutions containing either phosphatidase A or enzyme inhibitors. Acinar cells contained, besides nuclei, perinuclear droplets and secretion granules, various membranous and vacuolar structures. The basal cytoplasm showed parallel dark lines interpreted as endoplasmic reticulum. In some cells, fragmentation of the reticulum was followed by the direct incorporation of fragments into simple myelin figures. In other cells it appeared that phase-lucent linear structures and vacuoles were derived by dilatation of cisternae of the endoplasmic reticulum. Perinuclear fluid collections arose either by dilation of the perinuclear cisternae of the endoplasmic reticulum or by fluid dilatation of the nuclear envelope. Phosphatidase A disrupted early vacuoles of Walker carcinoma cells. From this and the direct involvement of elements of the endoplasmic reticulum in myelin figures, it was concluded that the membranes limiting the endoplasmic reticulum incorporate phosphatides in continuous layers. While many severely injured cells formed large vacuoles, others developed concentrically laminated myelin figures; it was concluded that both types of structure derived from phosphatides liberated intracellularly, the vacuoles by vesicular myelin figure formation.


2011 ◽  
Vol 33 (3) ◽  
pp. 765-773 ◽  
Author(s):  
Carla Rosana Eichelberger ◽  
Liana Johann ◽  
Fernanda Majolo ◽  
Noeli Juarez Ferla

Despite the importance of peach (Prunus persica (L.) Batsch) in Rio Grande do Sul, little is known about mites fluctuation population considered important to this crop. The objective of this study was to know the population diversity and fluctuation of mite species associated with Premier and Eldorado varieties in Roca Sales and Venâncio Aires counties, Rio Grande do Sul. The study was conducted from July 2008 to June 2009 when 15 plants were randomly chosen in each area. The plants were divided in quadrants and from each one a branch was chosen from which three leaves were removed: one collected in the apical region, another in the medium and the other in the basal region, totalizing 180 leaves/area. Five of the most abundant associated plants were collected monthly in enough amounts for the screening under the stereoscopic microscope during an hour. A total of 1,124 mites were found belonging to 14 families and 28 species. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836) and Mononychellus planki (McGregor, 1950) were the most abundant phytophagous mites, whereas Typhlodromalus aripo Deleon, 1967 and Phytoseiulus macropilis (Banks, 1904) the most common predatory mites. The period of one hour under stereoscopic microscope was enough to get a representative sample. In both places evaluated the ecologic indices were low, but little higherin Premier (H' 0.56; EqJ: 0.43) when compared to Eldorado (H' 0.53; EqJ 0.40). In Premier constant species were not observed and accessory only Brevipalpus phoenicis (Geijskes, 1939), T. ludeni and T. aripo. Higher abundance was observed in December and January and bigger amount in April. Already in Eldorado, T. ludeni and P. ulmi were constants. Greater abundance was observed in November and December, whereas grater richness in December and January. In both orchards were not found mites in buds. Tetranychus ludeni is the most abundant phytophagous mites with outbreak population in November, December and January and high predator diversity was observed on associated plants and on peach plants, indicating the existence of species mobility in peach orchard.


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