The Fine Structure of the Cockroach Subgenual Organ

1970 ◽  
Vol 28 ◽  
pp. 80-81
Author(s):  
David T. Moran
Keyword(s):  
Fine Structure ◽  
Circulatory System ◽  
Epidermal Cells ◽  
Mechanical Stimuli ◽  
Sense Organs ◽  
Fluid Medium ◽  
Blaberus Discoidalis ◽  
Highly Sensitive ◽  
Surrounding Fluid ◽  
Subgenual Organ

Insects are abundantly endowed with mechanoreceptors, sense organs that transduce mechanical stimuli into nerve impulses. Like most cockroaches, Blaberus discoidalis is highly sensitive to vibrations of the substrate on which it walks. This sensitivity is thought to be due in large part to the subgenual organ — an intricately constructed mechanoreceptor located near the proximal end of the tibia. The exoskeleton of the cockroach is secreted by a layer of epidermal cells which enclose the haemocoele of animal's open circulatory system. The subgenual organ is a thin, fan-shaped flap of tissue which is suspended from the epidermis and occludes much of the dorsal blood space in the hollow leg. It is therefore surrounded by blood on all sides; its position renders it susceptible to minor displacements of the surrounding fluid medium. Highly modified epidermal cells which are packed with hundreds of parallel microtubules support the subgenual organ as a ligament. The cells which compose the bulk of the organ are populated with a few mitochondria and many microtubules.

The tricornered Gene, Which Is Required for the Integrity of Epidermal Cell Extensions, Encodes the Drosophila Nuclear DBF2-Related Kinase

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1817-1828 ◽  
Author(s):  
Wei Geng ◽  
Biao He ◽  
Mina Wang ◽  
Paul N Adler
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Cell Structure ◽  
Cytochalasin D ◽  
Epidermal Cells ◽  
Sense Organs ◽  
Latrunculin A ◽  
Cellular Extensions ◽  
Cuticular Structures ◽  
Cuticular Surface

Abstract During their differentiation epidermal cells of Drosophila form a rich variety of polarized structures. These include the epidermal hairs that decorate much of the adult cuticular surface, the shafts of the bristle sense organs, the lateral extensions of the arista, and the larval denticles. These cuticular structures are produced by cytoskeletal-mediated outgrowths of epidermal cells. Mutations in the tricornered gene result in the splitting or branching of all of these structures. Thus, tricornered function appears to be important for maintaining the integrity of the outgrowths. tricornered mutations however do not have major effects on the growth or shape of these cellular extensions. Inhibiting actin polymerization in differentiating cells by cytochalasin D or latrunculin A treatment also induces the splitting of hairs and bristles, suggesting that the actin cytoskeleton might be a target of tricornered. However, the drugs also result in short, fat, and occasionally malformed hairs and bristles. The data suggest that the function of the actin cytoskeleton is important for maintaining the integrity of cellular extensions as well as their growth and shape. Thus, if tricornered causes the splitting of cellular extensions by interacting with the actin cytoskeleton it likely does so in a subtle way. Consistent with this possibility we found that a weak tricornered mutant is hypersensitive to cytochalasin D. We have cloned the tricornered gene and found that it encodes the Drosophila NDR kinase. This is a conserved ser/thr protein kinase found in Caenorhabditis elegans and humans that is related to a number of kinases that have been found to be important in controlling cell structure and proliferation.

scholarly journals ALTERATION OF HISTONES FROM MOUSE EPIDERMAL CELLS AFTER INCUBATION WITH ELASTASE AND HYALURONIDASE

1971 ◽  
Vol 19 (3) ◽  
pp. 182-185 ◽  
Author(s):  
ALVIN SEGAL ◽  
MARGARET SCHROEDER ◽  
BENJAMIN L. VAN DUUREN
Keyword(s):  
Mouse Liver ◽  
Mouse Skin ◽  
Analytical Techniques ◽  
Epidermal Cells ◽  
Ultraviolet Absorption Spectrum ◽  
Tissue Preparation ◽  
Standard Procedures ◽  
Highly Sensitive ◽  
Mammalian Tissues ◽  
Liver Chromatin

Chromatin was isolated from whole mouse skin, mouse epidermal cells and mouse liver by standard procedures used for isolation of chromatin from other mammalian tissues. Chromatin from whole mouse skin or from mouse epidermal cells had not been isolated or characterized earlier. For the preparation of chromatin from mouse epidermal cells, the latter was separated from dermis by incubation for 30 min at 37°C in a solution containing the enzymes elastase and hyaluronidase. The relative proportions of the chromatin components, the T m and the ultraviolet absorption spectrum were all similar to that of chromatin from whole mouse skin which was not treated with enzymes and to other mammalian chromatin preparations. Electrophoresis of the histones from epidermal chromatin in polyacrylamide gels revealed the absence of histones F1, F3 and F2a2 and the appearance of a new band. Histones isolated from chromatin prepared from the whole mouse skin had a gel electrophoresis pattern virtually identical with histones isolated from mouse liver chromatin and to reported histone patterns from other mammalian tissues. The alterations in mouse epidermal histones are similar to reported changes in histones from calf thymus nucleohistone previously subjected to incubation at various temperatures. The enzymatic incubation technique can therefore not be used as a method of isolating unaltered mouse epidermal chromatin. The findings illustrate that very subtle chemical alterations can be induced by usual methods of tissue preparation and that these changes can only be detected by highly sensitive analytical techniques.

scholarly journals A Highly Sensitive and Flexible Capacitive Pressure Sensor Based on a Porous Three-Dimensional PDMS/Microsphere Composite

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1412 ◽  
Author(s):  
Young Jung ◽  
Wookjin Lee ◽  
Kyungkuk Jung ◽  
Byunggeon Park ◽  
Jinhyoung Park ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Sacrificial Layer ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Capacitive Pressure Sensor ◽  
Mechanical Stimuli ◽  
Highly Sensitive ◽  
Flexible Pressure Sensors ◽  
Fast Rise ◽  
Better Than

In recent times, polymer-based flexible pressure sensors have been attracting a lot of attention because of their various applications. A highly sensitive and flexible sensor is suggested, capable of being attached to the human body, based on a three-dimensional dielectric elastomeric structure of polydimethylsiloxane (PDMS) and microsphere composite. This sensor has maximal porosity due to macropores created by sacrificial layer grains and micropores generated by microspheres pre-mixed with PDMS, allowing it to operate at a wider pressure range (~150 kPa) while maintaining a sensitivity (of 0.124 kPa−1 in a range of 0~15 kPa) better than in previous studies. The maximized pores can cause deformation in the structure, allowing for the detection of small changes in pressure. In addition to exhibiting a fast rise time (~167 ms) and fall time (~117 ms), as well as excellent reproducibility, the fabricated pressure sensor exhibits reliability in its response to repeated mechanical stimuli (2.5 kPa, 1000 cycles). As an application, we develop a wearable device for monitoring repeated tiny motions, such as the pulse on the human neck and swallowing at the Adam’s apple. This sensory device is also used to detect movements in the index finger and to monitor an insole system in real-time.

The fine morphology of the osphradial sense organs of the mollusca. III. Placophora and bivalvia

1987 ◽  
Vol 315 (1169) ◽  
pp. 37-61 ◽  
Keyword(s):  
Fine Structure ◽  
Sense Organ ◽  
Mantle Cavity ◽  
Sense Organs ◽  
Physiological Evidence ◽  
Anal Papillae ◽  
Fine Morphology

The fine morphology of the osphradia of six placophorans and eight bivalves, representing all major subgroups of both classes, is described. In addition the branchial and lateral sense organs of Lepidopleurus cajetanus (Placophora) have been investigated ultrastrucurally. Whereas osphradial fine structure is very uniform within the Bivalvia there are differences between Ischnochitonina and Acanthochitonina, supporting the separation of both groups. Major differences in the conditions of the mantle cavity divide Recent Placophora into the orders Lepidopleurida and Chitonida. The homology of the molluscan osphradium throughout the phylum is discussed in detail. It is concluded that the terminal sense organ (Caudofoveata, Solenogastres), the adanal sensory stripes (Placophora—Chitonida), the interbranchial and post-anal papillae of Nautilus (Cephalopoda), and the organ of Lacaze (Gastropoda-Basommatophora) are homologous with the organs of Spengel (Prosobranchia, Opisthobranchia, Bivalvia), all to be called osphradial sense organs (or osphradia). After discussion it is concluded that the osphradium is a chemoreceptor and not a mechanoreceptor as suggested by many authors. This is shown by the physiological evidence so far reported but mainly by the existence of paddle cilia in the osphradial epithelia throughout the Mollusca, which are typical of molluscan chemoreceptors. It is suggested that the osphradium is primarily used in sexual biology (coordination of spawning, search for a mate), a role altered within the Gastropoda (search for food, osmoreceptor, p O2 -receptor).

Compound sensilla in monogenean skin parasites

Parasitology ◽  
1969 ◽  
Vol 59 (3) ◽  
pp. 625-636 ◽  
Author(s):  
Kathleen M. Lyons
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Phase Contrast ◽  
The Other ◽  
Phase Contrast Microscopy ◽  
Sense Organs ◽  
Dense Membrane ◽  
Contrast Microscopy ◽  
Membrane Bound

The fine structure of two kinds of compound presumed sense organs from the heads of three skin parasitic monogeneans Gyrodactylus sp. Entobdella soleae (larva only) and Acanthocotyle elegans is described. One kind of compound receptor consists of a number of associated sensilla, each ending in a single cilium (the spike sensilla of Gyrodactylus and the cone sensilla of E. soleae oncomiracidium).The other kind of compound organ is made up of one or a few neurones only, each of which bears many cilia (pit organs of E. soleae oncomiracidium and feeding organ sensilla of Acanthocotyle elegans). The spike sensilla of Gyrodactylus have also been studied using a Cambridge Instrument Co. Stereoscan electron microscope and by phase-contrast microscopy. The ciliary endings of all these sense organs are highly modified and have lost the 9 + 2 structure, being packed with many fibres. The fibre arrangement in the cilia of the cone sensillae of E. soleae oncomiracidium and the feeding organ sensilla of A. elegans has been compared with that in the ciliary endings of other invertebrate mechano- and chemoreceptors. The possibility that the spike sensilla of Gyrodactylus may be chemoreceptors has been discussed but it is considered premature to attempt to assign functions to the other sense organs studied. Electron dense membrane-bound inclusions occurring specifically in the nerves supplying the spike sensilla of Gyrodactylus may be neurosecretory.

The fine morphology of the osphradial sense organs of the Mollusca. 1. Gastropoda, Prosobranchia

1985 ◽  
Vol 307 (1133) ◽  
pp. 457-496 ◽  
Keyword(s):  
Fine Structure ◽  
Environmental Conditions ◽  
Cell Types ◽  
Sensory Epithelium ◽  
Sense Organs ◽  
Group Iii ◽  
Close Relationship ◽  
Taxonomic Relations ◽  
Fine Morphology ◽  
Comparative Ultrastructure

The comparative ultrastructure of osphradia is investigated in 51 species of prosobranch gastropods, representative of nearly all superfamilies as well as of various habits and environments. The essential results show that the sensory epithelium of the osphradium as a whole may reflect environmental conditions, whereas the ultrastructure of osphradial cell types reflects actual taxonomic relations. Accordingly, the following taxa can be differentiated on the basis of osphradial fine structure: (i) the validity of the recently established taxon Vetigastropoda (Pleurotomarioidea, Fissurelloidea, and Trochoidea) is confirmed; (ii) the Docoglossa appear as a very isolated group; (iii) the osphradia of the Neritopsina are similar to those of the Caenogastropoda with respect to the organization of the sensory epithelium, but differ in cell types; (iv) in Valvatoidea the osphradium is indifferently elaborated, and no close relationship to other groups can be stated; (v) the Viviparoidea possess a special type of osphradium distinct from that of other taenioglossan groups; (vi) Neotaenioglossa (= Mesogastropoda partly), Heteroglossa (Cerithiopsoidea, Triphoroidea, Epitonioidea, Eulimoidea), and Stenoglossa (= Neogastropoda) represent an (unnamed) monophyletic stock which is characterized by three special cell types with a constant mutual positional relationship within the osphradial epithelium. On the basis of its structure the function of the osphradium is suggested to be chemoreceptive (also in Archaeogastropoda).

scholarly journals Structure-based membrane dome mechanism for Piezo mechanosensitivity

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Yusong R Guo ◽  
Roderick MacKinnon
Keyword(s):  
Mechanical Forces ◽  
Mechanical Stimuli ◽  
Membrane Tension ◽  
Structural Units ◽  
Projected Area ◽  
Closed Conformation ◽  
Channel Opening ◽  
Highly Sensitive ◽  
Touch Sensation ◽  
Area Expansion

Mechanosensitive ion channels convert external mechanical stimuli into electrochemical signals for critical processes including touch sensation, balance, and cardiovascular regulation. The best understood mechanosensitive channel, MscL, opens a wide pore, which accounts for mechanosensitive gating due to in-plane area expansion. Eukaryotic Piezo channels have a narrow pore and therefore must capture mechanical forces to control gating in another way. We present a cryo-EM structure of mouse Piezo1 in a closed conformation at 3.7Å-resolution. The channel is a triskelion with arms consisting of repeated arrays of 4-TM structural units surrounding a pore. Its shape deforms the membrane locally into a dome. We present a hypothesis in which the membrane deformation changes upon channel opening. Quantitatively, membrane tension will alter gating energetics in proportion to the change in projected area under the dome. This mechanism can account for highly sensitive mechanical gating in the setting of a narrow, cation-selective pore.

Organization of ampullary electric receptors in Gymnotidae (Pisces)

1968 ◽  
Vol 169 (1017) ◽  
pp. 345-378 ◽  
Keyword(s):  
Fine Structure ◽  
Evolutionary Relationships ◽  
Type I ◽  
Type Ii ◽  
Sense Organs ◽  
Large Numbers ◽  
Mode Of Operation ◽  
Points Of View ◽  
Eigenmannia Virescens ◽  
Electron Microscopes

Investigation of 14 species of gymnotid has established that large numbers of ampullary lateralis sense organs are present in each case. These organs have been examined with the light and electron microscopes. Two distinct types occur, and these are referred to as type I and type II; the latter is more common. The fine structure of the receptors in one species ( Eigenmannia virescens ) is described in detail, and is discussed from two points of view: (i) the function and mode of operation of the organs, and (ii) the evolutionary relationships to different receptors of the vertebrate acoustic-lateralis system.

Fine structure of Wolffia arrhiza

1973 ◽  
Vol 51 (9) ◽  
pp. 1619-1622 ◽  
Author(s):  
J. L. Anderson ◽  
W. W. Thomson ◽  
J. A. Swader
Keyword(s):  
Fine Structure ◽  
Cell Division ◽  
Vegetative Reproduction ◽  
Guard Cells ◽  
Epidermal Cells ◽  
Electron Microscopic ◽  
Meristematic Cells ◽  
Wolffia Arrhiza ◽  
Microscopic Studies

Light and electron microscopic studies of Wolffia arrhiza L. frond development during vegetative reproduction showed that the fronds were composed entirely of chlorenchymous cells. Chloroplasts in the epidermal cells other than the guard cells were unique in that they contained no starch. Cell division occurred only at the proximal end of daughter fronds early in their development. Meristematic cells contained chloroplasts with clearly defined grana. Proplastids, commonly observed in meristematic cells of apical regions of other plants, were absent in the cells of these plants.

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