Intermicrotubular actin filaments in the transalar cytoskeletal arrays of Drosophila

1988 ◽  
Vol 91 (3) ◽  
pp. 431-438 ◽  
Author(s):  
M.M. Mogensen ◽  
J.B. Tucker
Keyword(s):  
Cell Surface ◽  
Epidermal Cell ◽  
Basal Cell ◽  
Actin Filaments ◽  
Epidermal Cells ◽  
Rabbit Muscle ◽  
Drosophila Wing ◽  
Myosin Subfragment ◽  
Cell Layers ◽  
Muscle Myosin

Rabbit muscle myosin subfragment S1 decorates 6 nm diameter filaments in Drosophila wing epidermal cells in the arrowhead fashion characteristic of the binding of subfragment S1 to actin filaments. The filaments in question are concentrated between microtubules that are mostly composed of 15 protofilaments and form cell surface-associated transcellular bundles. There are indications that the majority of the actin filaments have the same polarity and that, like the microtubules, they may elongate from sites at the apical surfaces of the cells. The bundles of F actin and microtubules occur in dorsal and ventral epidermal cell layers of a wing blade. They are joined in dorso-ventral pairs by attachment desmosomes. These transalar cytoskeletal arrays may provide an example of a situation where actin filaments operate as stiffeners rather than active generators of force in conjunction with myosin. The arrays probably function as noncontractile pillars to maintain basal cell extensions and keep haemocoelic spaces open in the highly folded and expanding wing blades of late pupae.

scholarly journals Fluorochrome-coupled lectins reveal distinct cellular domains in human epidermis.

1986 ◽  
Vol 34 (3) ◽  
pp. 307-315 ◽  
Author(s):  
I Virtanen ◽  
A L Kariniemi ◽  
H Holthöfer ◽  
V P Lehto
Keyword(s):  
Endothelial Cells ◽  
Epidermal Cell ◽  
Basal Cell ◽  
Cell Layer ◽  
Lectin Binding ◽  
Epidermal Cells ◽  
Human Epidermis ◽  
Binding Pattern ◽  
Basal Cell Layer ◽  
Cell Layers

The distribution of saccharide moieties in human interfollicular epidermis was studied with fluorochrome-coupled lectins. In frozen sections Concanavalin A (Con A), Lens culinaris agglutinin (LCA), Ricinus communis agglutinin I (RCAI), and wheat germ agglutinin (WGA) stained intensively both dermis and viable epidermal cell layers, whereas peanut agglutinin (PNA) bound only to living epidermal cell layers. Ulex europaeus agglutinin I (UEAI) bound to dermal endothelial cells and upper cell layers of the epidermis but left the basal cell layer unstained. Dolichos biflorus agglutinin (DBA) bound only to basal epidermal cells, whereas both soybean agglutinin (SBA) and Helix pomatia agglutinin (HPA) showed strong binding to the spinous and granular cell layers. On routinely processed paraffin sections, a distinctly different staining pattern was seen with many lectins, and to reveal the binding of some lectins a pretreatment with protease was required. All keratin-positive cells in human epidermal cell suspensions, obtained with the suction blister method, bound PNA, whereas only a fraction of the keratinocytes bound either DBA or UEAI. Such a difference in lectin binding pattern was also seen in epidermal cell cultures both immediately after attachment and in organized cell colonies. This suggests that in addition to basal cells, more differentiated epidermal cells from the spinous cell layer are also able to adhere and spread in culture conditions. Gel electrophoretic analysis of the lectin-binding glycoproteins in detergent extracts of metabolically labeled primary keratinocyte cultures revealed that the lectins recognized both distinct and shared glycoproteins. A much different lectin binding pattern was seen in embryonic human skin: fetal epidermis did not show any binding of DBA, whereas UEAI showed diffuse binding to all cell layers but gave a bright staining of dermal endothelial cells. This was in contrast to staining results obtained with a monoclonal cytokeratin antibody, which showed the presence of a distinct basal cell layer in fetal epidermis also. The results indicate that expression of saccharide moieties in human epidermal keratinocytes is related to the stage of cellular differentiation, different cell layers expressing different terminal saccharide moieties. The results also suggest that the emergence of a mature cell surface glycoconjugate pattern in human epidermis is preceded by the acquisition of cell layer-specific, differential keratin expression.

Changes in the 31P NMR spectrum of rabbit muscle myosin subfragment 1 ·MgADP with temperature

2002 ◽  
Vol 402 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Bruce D Ray ◽  
Mikhail I Khoroshev ◽  
Kathleen Ue ◽  
Manuel F Morales ◽  
B.D Nageswara Rao
Keyword(s):  
31P Nmr ◽  
Rabbit Muscle ◽  
Nmr Spectrum ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Muscle Myosin

scholarly journals Modification of cell surface glycoprotein: addition of fucosyl residues during epidermal differentiation.

1982 ◽  
Vol 95 (2) ◽  
pp. 626-631 ◽  
Author(s):  
J D Zieske ◽  
I A Bernstein
Keyword(s):  
Cell Surface ◽  
Lectin Binding ◽  
Epidermal Cells ◽  
Epidermal Differentiation ◽  
Surface Glycoprotein ◽  
Basal Cells ◽  
Cell Surface Glycoprotein ◽  
Similar Treatment ◽  
Differentiated Cells ◽  
Cell Layers

When cutaneous sections from the newborn rat were treated with alpha-fucosidase, Ulex europeus agglutinin I (UEA) binding to the cell surface of the differentiated cells in the epidermis was diminished and there was an appearance in these cell layers of binding by Bandeiraea simplicifolia I-B4 lectin (BS I-B4), which normally is specific for the basal cells. A similar treatment with alpha-galactosidase resulted in a loss of BS I-B4 binding, but had no effect on UEA binding. Glycoproteins isolated from the membranes of epidermal cells showed a threefold increase in the ratio of binding to UEA versus BS I-B4 affinity columns as the proteins were derived from the more differentiated cell populations. These data suggest that alpha-fucosyl residues are added to the glycoproteins on the cell surfaces of differentiated cells, thus blocking alpha-galactosyl residues and changing the lectin binding specificity as epidermal cells move out of the basal cell layer.

scholarly journals Pigment Distribution and Epidermal Cell Shape in Dendrobium Species and Hybrids

HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 573-577 ◽  
Author(s):  
Rasika G. Mudalige ◽  
Adelheid R. Kuehnle ◽  
Teresita D. Amore
Keyword(s):  
Epidermal Cell ◽  
Cell Shape ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Color Intensity ◽  
Visual Texture ◽  
Intensity Perception ◽  
Cell Layers ◽  
Cell Shapes ◽  
Pigment Distribution

Perianths of 34 Dendrobium Sw. species and hybrids were examined to elucidate the roles of pigment distribution and shape of upper epidermal cells in determining color intensity, perception, and visual texture. Color intensity was determined by the spatial localization of anthocyanin in tissue layers, i.e., in the epidermal, subepidermal, and mesophyll layers, as well as by distribution of pigmented cells within the tissue layer. Anthocyanins were confined to the epidermal layer or subepidermal layer in flowers with low color intensity, whereas they were also in several layers of mesophyll in more intensely colored flowers. Striped patterns on the perianth were due to the restriction of pigment to cells surrounding the vascular bundles. Color perception is influenced by the presence or absence of carotenoids, which when present, were distributed in all cell layers. Anthocyanins in combination with carotenoids resulted in a variety of flower colors ranging from red, maroon, bronze to brown, depending on the relative location of the two pigments. Four types of epidermal cell shapes were identified in Dendrobium flowers: flat, dome, elongated dome, and papillate. Epidermal cell shape and cell packing in the mesophyll affected the visual texture. Petals and sepals with flat cells and a tightly packed mesophyll had a glossy texture, whereas dome cells and loosely packed mesophyll contributed a velvety texture. The labella in the majority of flowers examined had a complex epidermis with more than one epidermal cell shape, predominantly papillate epidermal cells.

scholarly journals Response of basal epithelial cell surface and Cytoskeleton to solubilized extracellular matrix molecules.

1981 ◽  
Vol 91 (1) ◽  
pp. 45-54 ◽  
Author(s):  
S P Sugrue ◽  
E D Hay
Keyword(s):  
Extracellular Matrix ◽  
Cell Surface ◽  
Basal Cell ◽  
Actin Filaments ◽  
Cell Cortex ◽  
Collagen Gels ◽  
Basal Surface ◽  
Extracellular Matrix Components ◽  
Cytoplasmic Processes

Corneal epithelium removed from underlying extracellular matrix (ECM) extends numerous cytoplasmic processes (blebs) from the formerly smooth basal surface. If blebbing epithelia are grown on collagen gels or lens capsules in vitro, the basal surface flattens and takes on the smooth contour typical of epithelium in contact with basal lamina in situ. This study examines the effect of soluble extracellular matrix components on the basal surface. Corneal epithelia from 9- to 11-d-old chick embryos were isolated with trypsin-collagenase or ethylenediamine tetraacetic acid, then placed on Millipore filters (Millipore Corp., Bedford, Mass.), and cultured at the medium-air interface. Media were prepared with no serum, with 10% of calf serum, or with serum from which plasma fibronectin was removed. Epithelia grown on filters in this medium continue to bleb for the duration of the experiments (12-14 h). If soluble collagen, laminin, or fibronectin is added to the medium, however, blebs are withdrawn and by 2-6 h the basal surface is flat. Epithelia grown on filters in the presence of albumin, IgG, or glycosaminoglycans continue to bleb. Epithelia cultured on solid substrata, such as glass, also continue to bleb if ECM is absent from the medium. The basal cell cortex in situ contains a compact cortical mat of filaments that decorate with S-1 myosin subfragments; some, if not all, of these filaments point away from the plasmalemma. The actin filaments disperse into the cytoplasmic processes during blebbing and now many appear to point toward the plasmalemma. In isolated epithelia that flatten in response to soluble collagens, laminin, and fibronectin, the actin filaments reform the basal cortical mat typical or epithelial in situ. Thus, extracellular macromolecules influence and organize not only the basal cell surface but also the actin-rich basal cell cortex of epithelial cells.

scholarly journals Stratification, specialization, and proliferation of primary keratinocyte cultures. Evidence of a functioning in vitro epidermal cell system.

1978 ◽  
Vol 79 (2) ◽  
pp. 356-370 ◽  
Author(s):  
C L Marcelo ◽  
Y G Kim ◽  
J L Kaine ◽  
J J Voorhees
Keyword(s):  
Cell Culture ◽  
Epidermal Cell ◽  
Cell Layer ◽  
Primary Cultures ◽  
Mouse Skin ◽  
Epidermal Cells ◽  
Neonatal Mouse ◽  
Histological Techniques ◽  
Cell Layers ◽  
Epidermal Cell Culture

A population of neonatal mouse keratinocytes (epidermal basal cells) was obtained by gentle, short-term trypsin separation of the epidermal and dermal skin compartments and discontinuous Ficoll gradient purification of the resulting epidermal cells. Over 4--6 wk of culture growth at 32--33 degrees C, the primary cultures formed a complete monolayer that exhibited entire culture stratification and upper cell layer shedding. Transmission and scanning electron microscopy demonstrated that the keratinocyte cultures progressed from one to two cell layers through a series of stratification and specialization phenomena to a six to eight cell layer culture containing structures characteristic of epidermal cells and resembling in vivo epidermal development. The temporal development of primary epidermal cell culture specialization was confirmed by use of two histological techniques which differentially stain the specializing upper cell layers of neonatal mouse skin. No detectable dermal fibroblast co-cultivation was demonstrated by use of the leucine aminopeptidase histochemical technique and routine electron microscope surveillance of the cultures. Incorporation of [3H]thymidine ([3H]Tdr) was greater than 85% into DNA and was inhibited by both 20 micron cytosine arabinoside (Ara-C) and low temperature. Autoradiography and 90% inhibition of [3H]Tdr incorporation by 2 mM hydroxyurea indicated that keratinocyte culture DNA synthesis was scheduled (not a repair phenomenon). The primary keratinocytes showed an oscillating pattern of [3H]Tdr incorporation into DNA over the initial 23--25 days of growth. Autoradiography demonstrated that the cultures contained 10--30% proliferative stem cells from days 2-25 of culture. The reproducibility of both the proliferation and specialization patterns of the described primary epidermal cell culture system indicates that these cultures are a useful tool for investigations of functioning epidermal cell homeostatic control mechanisms.

Studies on the achene morphology of Turkish species of Scorzonera L. (Asteraceae) using light and scanning electron microscopy

Phytotaxa ◽  
2016 ◽  
Vol 247 (1) ◽  
pp. 1 ◽  
Author(s):  
Kamil Coşkunçelebi ◽  
Serdar Makbul ◽  
Seda Okur
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Surface ◽  
Epidermal Cell ◽  
Epidermal Cells ◽  
Surface Pattern ◽  
Epidermal Surface ◽  
Surface Patterns ◽  
Periclinal Walls ◽  
Scanning Electron

Macro- and micromorphological features of achenes belonging to 59 taxa from Turkey were observed via light and scanning electron microscopy. The findings agree with the traditional subdivision of Scorzonera into S. subg. Scorzonera, S. subg. Podospermum and S. subg. Pseudopodospermum. Members of S. subg. Podospermum were distinguished by achenes with a distinct carpopodium and horizontally striped epidermal cell surface; members of S. subg. Pseudopodospermum were distinguished by achenes with a conspicuous carpopodium and often ruminate and sometimes rugose-granulate or smooth epidermal surface, and members of Scorzonera s.str were distinguished by achenes without a carpopodium and with various combinations of surface patterns. The results also showed that the length, pubescence and surface pattern of achenes, as well as the carpopodium and anticlinal and periclinal walls of the epidermal cells are valuable for delimiting the examined species within the genus.

The Cuticle and Associated Structures of Podura Aquatica at the Moult

1963 ◽  
Vol s3-104 (67) ◽  
pp. 369-391
Author(s):  
J. NOBLE-NESBITT
Keyword(s):  
Cell Surface ◽  
Epidermal Cell ◽  
Epidermal Cells

At the beginning of a moult a foam secretion appears between the epidermal cell surface and the old cuticle. This secretion is involved only with the lifting away of the old cuticle and formation of the exuvial space. A granular secretion then appears in the exuvial space. The granules contain inactive moulting enzymes, which become active only after the completion of the new cuticulin layer, and then digest the soft parts of the old cuticle. The rest of the new cuticle is laid down extracellularly and in lamellae below the cuticulin layer. The sculpturing of the new cuticle occurs under the influence of the epidermal cells. Subsequent hardening of certain areas of the new cuticle involves disruption of the lamellae and complete reorganization. Setae are formed early and rapidly, but nervous connexions with the old setae are maintained until just before ecdysis. Muscle insertions into the new cuticle are formed early, but attachment to the old cuticle is retained until ecdysis. The cuticulin layer is involved in the formation of the new attachments.

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