Tubular Bodies Research Articles

Cavitating penetration of a plastic medium by bodies of minimum resistance

An approximate approach to the description of the deep penetration of a plastic medium by elongated bodies [1] is developed. The results obtained in [2–5] are generalized to another geometry and to a wider range of velocities, which is subdivided into intervals. An attempt is made to provide an averaged description of the motion in each of the intervals assuming quasistationarity, and the formula for the depth of penetration is analysed. Lavrent'yev's idea on the closeness of the velocity and stress fields during the high-velocity motions of bodies in a solid medium and in a liquid, which has been translated into the language of asymptotic representations [5], has been further developed in an hypothesis on the closeness of the configurations of bodies of minimum resistance in a plastic medium and a liquid subject to the condition of the smallness of the ratio of the strength (resistance) force to the hydrodynamic drag force. The advantage of tubular bodies compared with solid bodies with respect to mass and depth of penetration is indicated. The bounds of the limiting penetration depths are estimated.

Fine structure of the rectal pads in the desert locust Schistocerca gregaria with reference to the mechanism of water uptake

The rectal pads of Schistocerca gregaria are composed of three different cell types: epithelial, secondary and junctional cells. The rectal pads are interconnected by simple rectal cells and both are lined internally by a articular intima. The epithelial cells exhibit extensive infoldings of the apical plasma membranes that are closely associated with mitochondria. Their lateral plasma membranes are highly folded around large mitochondria and enclose intercellular channels and spaces. They are united by belt and spot desmosomes, septate junctions, gap junctions and scalariform junctions, but terminate in a basal syncytium without contacting the basal plasma membranes. The apical and basal cytoplasm contain coated vesicles, dense tubular elements, multivesicular bodies and lysosomes, suggesting receptor-mediated endocytosis of small peptide molecules into the epithelial cells. The apical membrane infoldings of the secondary cells are also associated with large mitochondria. Their basal plasma membranes are covered by connective cell processes and connected with them by spot desmosomes which may be involved in solute recycling. The presence of neurosecretory-like axons near the secondary cells suggests that they exert local control on the function of these cells. The ultrastructural details are examined in relation to their role in solute and water transport.

Hyperthermia induced ultrastructural changes in Stylonychia mytilus cells

1. 1.|Ultrastructural organization of Stylonychia mytilus (a ciliated protozoan) cells is studied in response to hyperthermia treatment (30°C). 2. 2.|Cytoplasmic organization is altered as compared to the control cells grown at 23°C. The channel system expands and thereby restricts the membrane-bound cytoplasm. Tubular bodies of the channel system are scarce. Vesicles of the rough endoplasmic reticulum show dilation and there is persistent development of smooth endoplasmic reticulum. 3. 3.|Membrane-bound vesicles containing osmiophilic bodies appear in these cells. Macronuclear chromatin gets dispersed, shows a reticular pattern of dense chromatin an the appearance of microfilaments (4–5 nm). Nucleoli are hypertrophied and develop a fine fibrillar are in the centre with a fibrillar and granular zones at the rim. 4. 4.|The study reveals the subcellular adaptations of heat treated Stylonychia cells which otherwise exhibit normal external morphology and growth characteristics.

Morphology and ultrastructure of the sensory spine, a presumed mechanoreceptor of Sphaeroma hookeri (Crustacea, Isopoda), and remarks on similar spines in other peracarids.

The isopod Sphaeroma hookeri and many other isopods and peracarids have a sensory spine with laterally inserting sensory hair, positioned in the apical region of the propodal palm of pereopod 1. This spine is innervated by five to eight sensory cells (each giving rise to one cilium) the dendrites of which can be divided into an inner and outer dendritic segment. The cilia are surrounded by an extracellular, electron-dense dendritic sheath. Thirteen enveloping cells are present. The outer dendritic segment (structure beyond the basal bodies) contains two receptor lymph cavities; the inner one lying within the dendritic sheath is homologous with the inner receptor lymph cavity of insects. Scolopales, or tubular bodies, are lacking; their function is probably accomplished by the dendritic sheath. Apically the sensory hair does not have a pore, and the spine is heavily sclerotized. The inner dendritic segment begins with a basal body from which rootlets of different length and thickness extend into the dendrite. In the latter is an accumulation of vesicles. The dendrites keep close contact with other dendrites and the enveloping cells by desmosomal membrane structures. The possible importance of the sensory spine for phylogenetic studies is discussed.

Ultrastructure of oogenesis in the holopelagic polychaetes Rhynchonerella angelini and Alciopa reynaudii (Polychaeta: Alciopidae)

Ultrastructural features of oogenesis were examined in the pelagic polychaetes Rhynchonerella angelini and Alciopa reynaudii which were collected from Bahamian waters by a manned submersible during 1979 and 1980. No definitive ovary was detected in either species. Oogonia are released into the coelom as packets of cells, where they undergo mitotic division while surrounded by an envelope of sheath cells. Cytokinesis is incomplete, resulting in intercellular bridges between oogonia. Oocytes undergo early stages of meiosis characterized by the presence of synapsed chromosomes, followed by a period of rapid cytoplasmic and nuclear growth. Oocytes are released from the packets in the early vitellogenic phase into the coelom, where they undergo yolk synthesis as solitary coelomic cells. Vitellogenesis includes both autosynthetic and heterosynthetic processes. Autosynthesis involves the fusion of secretory vesicles formed by the combined activity of the rough endoplasmic reticulum and Golgi complex, with convoluted electron-dense tubular bodies of unknown origin. Heterosynthesis involves the intense uptake of exogenous precursors through endocytosis and their fusion into nascent yolk bodies which, in turn, are presumed to fuse with autosynthetically-derived yolk bodies. No nutrient stores were detected in somatic tissues. Early and middle stages of vitellogenic oocytes were absent from the coelom. This absence combined with the high level of endocytotic activity suggests that vitellogenesis occurs rapidly. These features, in combination with the presence of an exceptionally thin body wall and gut, might serve as related adaptations for predator avoidance by the maintenance of relatively low tissue-density. Alciopid, phyllodocid, and nereid polychaetes share some common reproductive features including the presence of “dispersed” ovaries, clusters of syncytial germ cells which undergo meiosis while enveloped by somatic cells and the release of oocytes from the clusters prior to vitellogenesis.

Antennal sensory organs in the millipede Eurypauropus ornatus: Fine structure of the flagella and globulus.

On the antennal tip of Eurypauropus ornatus are 3 threadlike sensilla-the flagella, and a single spheroid sensillum-the globulus. Each of the 3 flagella is innervated by 2 groups of sensory cells. One group contains 4 cells, the other, 5. All cells of the "four group" and 3 of the "five group" are comprised of single cilia and unbranched dendrites which extend along the lumen of the flagellum. Two cells of the "five group" have double cilia and pairs of unbranched dendrites. One pair also enters the flagellum and the other pair terminates beneath the flagellar base to form a concentric array of lamellae. No pores are present in the cuticular wall. Eight sensory cells innervate the globulus. They are arranged in 3 groups, one triplet and 2 pairs, in addition to a single cell. The single cell contains a pair of cilia whose unbranched dendrites differentiate into tubular bodies that are inserted into the base of the globulus. Each of the other 7 sensory cells has a single cilium. Their unbranched dendrites penetrate into the globulus in 3 groups as described for the sensory cells. The dendrites in each group terminate in an individual pore channel at the globulus tip and completely fuse with the electron-dense material that plugs the pore channel. Based on structural similarities to sensilla having known functions, it is probable that the flagella and the globulus are chemoreceptors, the former responding to odors, the latter sensitive to substances in aqueous solution.

Supersonic aerodynamics of spinning tubular bodies

Supersonic aerodynamics of spinning tubular bodies

Mutant sensory cilia in the nematode Caenorhabditis elegans

Eight classes of chemosensory neurons in C. elegans fill with fluorescein when living animals are placed in a dye solution. Fluorescein enters the neurons through their exposed sensory cilia. Mutations in 14 genes prevent dye uptake and disrupt chemosensory behaviors. Each of these genes affects the ultrastructure of the chemosensory cilia or their accessory cells. In each case, the cilia are shorter or less exposed than normal, suggesting that dye contact is the principal factor under selection. Ten genes affect many or all of the sensory cilia in the head. The daf-19 (m86) mutation eliminates all cilia, leaving only occasional centrioles in the dendrites. The cilia in che-13 (e1805), osm-1 (p808), osm-5 (p813), and osm-6 (p811) mutants have normal transition zones and severely shortened axonemes. Doublet-microtubules, attached to the membrane by Y links, assemble ectopically proximal to the cilia in these mutants. The amphid cilia in che-11 (e1810) are irregular in diameter and contain dark ground material in the middle of the axonemes. Certain mechanocilia are also affected. The amphid cilia in che-10 (e1809) apparently degenerate, leaving dendrites with bulb-shaped endings filled with dark ground material. The mechanocilia lack striated rootlets. Cilia defects have also been found in che-2, che-3, and daf-10 mutants. The osm-3 (p802) mutation specifically eliminates the distal segment of the amphid cilia. Mutations in three genes affect sensillar support cells. The che-12 (e1812) mutation eliminates matrix material normally secreted by the amphid sheath cell. The che-14 (e1960) mutation disrupts the joining of the amphid sheath and socket cells to form the receptor channel. A similar defect has been observed in daf-6 mutants. Four additional genes affect specific classes of ciliated sensory neurons. The mec-1 and mec-8 (e398) mutations disrupt the fasciculation of the amphid cilia. The cat-6 (e1861) mutation disrupts the tubular bodies of the CEP mechanocilia. A cryophilic thermotaxis mutant, ttx-1 (p767), lacks fingers on the AFD dendrite, suggesting this neuron is thermosensory.

Fine structure of sensilla on the ovipositor of the tephritid fly Urophora affinis

There are four types of sensilla on the ovipositor blade of Urophora affinis Frauenfeld, one more than was observed on three other species of fruit flies studied by other authors. Three of the types, uniporous gustatory pegs, campaniform organs, and tactile short hairs are common to the four species and generally are in similar positions on the blade. The fourth, uniporous gustatory plates, were noted in U. affinis only. The chemosensilla are innervated by three chemosensory dendrites that terminate below the pore and a mechanosensory dendrite with a tubular body that is attached to a basal cuticular apodeme of the covering cuticle. The dendritic tubular bodies of the campaniform organs and tactile hairs terminate parallel to the surface in a right-angular bend, where they are attached to basal apodemes of the covering cuticle. The chemosensilla and tactile hairs have individual outer and inner sheath cells, but the campaniform organs have individual inner sheath cells only. The part of the ciliary dendritic segment that is encased by the dendritic sheath passes through an epidermal cell, often with several sensilla sharing the same epidermal cell in place of an outer sheath cell. The role of these sensilla during oviposition is discussed.

The coxo-trochanteral muscle receptor organ of locusts

The coxo-trochanteral muscle receptor organ of the hind leg of the locust Locusta migratoria migratorioides (R.F (2) the naked dendritic terminals of the non-ciliated, multipolar sensory neuron of the organ contain clusters of microtubules, interconnected by an amorphous matrix, that resemble the tubular bodies of ciliated, epithelial receptor cells.

Prey finding behavior and mechanosensilla of larval Toxorhynchites brevipalpis Theobald (Diptera : Culicidae)

Behavioral experiments demonstrated that starved 3rd-instar Toxorhynchites brevipalpis (Diptera : Culicidae) will attack a glass probe in response to vibrations alone. Frequencies in the range of 80–200 Hz elicited 85% of the attacks. The observation that most attacks occurred while the larva was drifting forward towards the probe, substantiates that the predatory behavior of these organisms is basically opportunistic. The main setae on the thorax and abdomen arise from setal support plates and are of 4 general morphological types: dendritic, smooth, spinulate spiniform, and unbranched aciculate setae. The numbers and lengths of the setae on 3rd- and 4th-instar larvae are given. Each seta is innervated by a bipolar neuron with a tubular body in the dendrite, a characteristic of mechanosensilla. By virtue of their abundance and location, it seems probable that one or more types of these setae sense the water vibrations capable of eliciting an attack response. The tubular bodies of the 4 types of setae are somewhat unusual in that they lack electron-dense material, except near sites of attachment of the microtubules to the dendritic membrane, yet possess a large number of complexly arranged microtubules. Among the setal types, variations were observed in the prominence of microtubular attachment sites, proportion of tubules associated with the sites, and orientation of microtubules. In spinulate spiniform setae, the arrangement of microtubules varies within the same tubular body; peripherally most of the microtubules are in one direction with little convergence and have only one distinct attachment site, whereas medially they converge considerably resulting in 2 groups, each associated with its own well-defined site. The attachment sites, which presumably through linkage with the dendritic membrane provide a means of initiating depolarization, are associated with the distal ends of almost all of the microtubules. This suggests that in these tubular bodies depolarization may be initiated through mechanical force acting along the length of the microtubules, that is, stretching and/or compression.

Ultrastructure of chemoreceptors on the pedipalps and first tarsi ofPhytoseiulus persimilis

The ultrastructure of pedipalpal and tarsal setae ofPhytoseiulus persimilis Athias-Henriot has been investigated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The setae on top of the tarsi of the pedipalps are innervated by either 11–12 dendrites or 4–8 dendrites. Two of these dendrites terminate in tubular bodies, just below the articulation membrane of the sockets present at the setal base. Only one seta in the centre appears to be provided with two pairs of tubular bodies. Cross-sections of the palp tarsal setae revealed a crescent-shaped lumen and a rounded lumen, but just below the tip a small porous area is indicated by the exclusive presence of some blobs of material on the external hair shaft. These blobs are presumed to be secreted through terminal pores. The ultrastructure of the palpal setae is in agreement with the description of known contact chemoreceptors in insects, ticks and spiders. The sensilla on the dorsal surface of the anterior tarsi are either long, tapering socketed setae or short, blunt-tipped setae with or without sockets. Some of the short setae are shown to be innervated and their walls contain numerous pores. Three pore-types can be distinguished: (1) funnel-shaped pores in single-wall setae; (2) slit-pores with coneshaped connections in the second wall to the inner fluid; and (3) spoke canals with a mushroom-shaped connection to the inner fluid in setae with an incomplete second wall. The short setae examined differed from each other in pore structure, number of lumina and innervation. Except for some slight differences in pore structures the ultrastructure of these setae conforms with the descriptions of chemoreceptive (or thermosensory) sensilla found in ticks and insects.

Interactions between the Nucleus and Cytoplasmic Organelles during the Cell Cycle of Euglena gracilis in Synchronized Cultures III. Association between the Nucleus and Chloroplasts at an Early Stage in the Cell Cycle under Photoorganotrophic Conditions (Part II)1

Three-dimensional models of chloroplasts before and during their association with the nucleus in Euglena gracilis Z were constructed based on serial sections of cells taken during an early phase of the cell cycle in synchronized cultures under photoorganotrophic condition. Before association, the cell contained two to three chloroplasts which were composed of elongated tubular bodies extending in different directions toward the cell periphery. These tubular arms of chloroplasts were drawn toward the nucleus, and folded, with concurrent coalescence, into a single giant body surrounding the nucleus. A DAPI-fluorescence photomicrograph of a giant chloroplast revealed that the chloroplast-nucleoids were in the form of a continuous strand lying throughout the chloroplast body, and that some protuberances from the nucleoid strand were in especially close proximity to the nuclear periphery. A new mode of the chloroplast-nucleus connection was observed. The nucleus had conspicuous protrusions, whose distal ends were connected with the chloroplast. The outer membrane of the nuclear envelope was continuous with the outer chloroplast membrane, and at some sites, an open space was formed between the inner nuclear membrane and the inner chloroplast membrane.

Immunocytochemical Localization of Factor VIII-related Antigen and Tubular Bodies (Weibel-Palade Bodies) in Blood Vessels of Human Gliomas

The authors have studied the distribution of factor Vi-related antigen (FVMR: Ag) using both immunohistochemical and immunoelectron microscopic techniques with periodate-lysine-paraformaldehyde fixation and tubular bodies (Weibel-Palade bodies) in endothelial cells in 15 cases of gliomas and 3 samples of non-tumor brain tissue. Twelve glioblastoma, 1 ependymoma, 1 astrocytoma grade II, and 1 oligodendroglioma were evaluated. On FVIIIR: Ag study 7 non-filial tumors (2 metastatic tumor, 3 meningioma, 1 hemangioblastoma, and 1 chordoma) were compared with gliomas. FVIIIR: Ag was localized to the vascular lumen, to the intercellular spaces between endothelial cells (apparently without tight junctions), and to the endothelial cell basement membrane. In the cytoplasm of the endothelial cells FVIIIR: Ag was found in the endoplasmic reticulum, perinuclear space, intracytoplasmic vacuoles, vesicles, and luminal surfaces of endothelial cell membranes. Characteristic of malignant tumors (6 out of 7), especially in the cases having endothelial proliferation or hyperplasia, it was strongly-positive at the dilated endoplasmic reticulum, whereas only 1 of 5 benign tumors showed such staining. These findings suggest that FVfIR: Ag synthesis occurs more effectively in the endothelial cells of malignant tumors, such as glioblastoma. The tubular body (Weibel-Palade body) observed in the endothelial cells of the glioma vessels consisted of a membrane-limited round, oval or elongated intracytoplasmic body (about 0.1-0.2 μm) which contained tubules of 150-200 Å outer diameter. Tubular bodies were classified into two types. One of them, mature type, is relatively electron dense, the other, immature type, has a relatively pale matrix. The immature types were located in close proximity to the Golgi complex or endoplasmic reticulum. Tubular bodies were common only in the endothelial cells in the marginal zones of glioblastoma with respect to the increased microvessels. In the endothelial cells of glioblastoma they appeared more prominently consistent with neovascularity than with benign glioma. It is suggested that large numbers of tubular bodies may be a marker for proliferating endothelial cells.

Adjuster means for headset

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Fine structure of antennal mechanosensilla of adult Rhodnius prolixus stål (Hemiptera: Reduviidae).

Each antenna of both sexes of adult Rhodnius prolixus has approximately 570 mechanosensitive neurons that innervate five morphologic types of cuticular mechanosensilla: campaniform sensilla, tapered hairs, trichobothria, and type I and type II bristle sensilla. Each campaniform sensillum and tapered hair is presumably innervated by one mechanosensitive bipolar neuron and probably functions in proprioception. The campaniform sensilla being located at the base of the scape could monitor the position of the antenna. Tapered hairs are found at the distal margin of flagellar segment I and projecting laterally from the bases of the pedicel and scape. They probably provide information about the relative positions of the antennal segments. Seven trichobothrium are located on the pedicel and three on flagellar segment I. Each trichobothrium has a long filamentous hair inserted into the base of a socket that extends inwardly as a cuticular tube and is innervated by one bipolar neuron with a tublar body, a parallel arrangement of microtubules associated with electron-dense material. The trichobothria may respond to small variations in air currents. Type I bristles occur at the base of the antenna and are the most numerous type of mechanosensillum; an average of 452 occur on each antenna of females and 440 on males. The bristle is curved toward the antennal shaft and is serrated distally. Type II bristles are located distally and are the second most numerous type of mechanosensillum; an average of 88 were counted on each antenna of females and 94 on males. The type II bristle is straight with small, longitudinal, external grooves and projects laterally from the antennal shaft. Each type I and II bristle sensillum is innervated by a bipolar neuron whose dendrite is divided into an inner and outer segment. The outer segment is encased by a dendritic sheath which may be highly convoluted and distally contains a tubular body. Two sheath cells are associated with each sensillum. Both types of bristle sensilla have a tactile function. The tubular bodies of both types of bristle sensilla have a complex structure indicating that they are very sensitive. Variations in the amount and arrangement of the electron-dense material at the tip of the tubular bodies may reflect differences in viscoelastic properties that underlie functional characteristics.

Warm and cold receptors of two sensilla on the foreleg tarsi of the tropical bont tickAmblyomma variegatum

A pair of antagonistic thermal receptors has been identified in each of two long, tapering, poreless setae located distally on the foreleg tarsi of the tropicalbont tick,Amblyomma variegatum (Fig. 1). One, the cold receptor, responds to a rapiddrop in temperature (T) with a sudden rise in impulse frequency (F). The other, a warm receptor, responds to a rapidrise inT with a sudden rise inF (Figs. 2, 4). These two units are unusual for sharing their seta with two other units which are mechanosensitive. The four are distinguishable on the basis of spike amplitude and form (Fig. 3). Hence the thermal sensitivity displayed is hardly attributable to the pair of cells with tubular bodies but rather to the two extending up into the seta (for structure, see Hess and Vlimant 1982, 1983 a).

Ultrastructural study of Pisdnoodinium pillulare (Schäperclaus, 1954) Lom, 1981 with special emphasis on its attachment to the fish host

Abstract. Trophonts of Pisdnoodinium pillulare (Schäperclaus, 1954), a common ectoparasite of freshwater aquarium fish, are attached to host cells by means of a specialized structure, the attachment disc. Unlike other dinoflagellate genera parasitic on fish and invertebrates, this disc features nail‐like organelles, the rhizocysts. Head‐parts of the rhizocysts are inverted in separate compartments, rhizothecas, in the sole of the disc while their long shafts are firmly embedded in the cytoplasm of cells of the host epidermis or gill epithelium. The attachment inflicts a serious injury on the host cells which may ultimately be destroyed. Rhizocysts originate in the subnuclear cytoplasm from where they migrate into the attachment disc. There are other specialized organelles and inclusions; fibrous vesicles, membraneous bodies, striated tubular bodies and paracrystalline bodies. Pisdnoodinium has well‐developed chloroplasts. While its cytological adaptations indicate a nutritional dependence on the host, there is no evidence of ingestion of host‐derived particulate material. Pisdnoodinium may derive an essential part of its nutrition from photosynthesis.

Vibration isolation structure

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Acute Tubular Necrosis in Hepatorenal Syndrome: An Electron Microscopy Study

This report describes light and transmission electron microscopy (LM and EM, respectively) studies of kidneys from five cases of hepatorenal syndrome. The kidneys were removed and fixed for LM and EM between 30 and 120 min after death. All patients had progressive renal failure after admission to the hospital. All cases were jaundiced, had ascites, and exhibited features of hepatic encephalopathy. LM study revealed severe acute tubular lesions (ATL) or, more conventionally, acute tubular necrosis (ATN). EM study demonstrated necrosis of the proximal tubules characterized by swelling, disorganization of the cristae and appearance of dark bodies in the mitochondria, coalescence, fragmentation or displacement of the microvilli, loss of plasma membranes, rupture of the basement membranes, and separation of the cells from the basement membranes. Rupture of tubular basement membranes (tubulorrhexis) and mitochondrial dark bodies suggest an ATN due to ischemia or induced by vasoconstrictor substance(s). Glomerular lesions were infrequent (one in five) and therefore, do not seem to have contributed to renal failure. All cases terminally had extremely low urinary sodium (11 mEq/liter), high urinary potassium (50 mEq/liter), a remarkably low urinary sodium/potassium ratio (0.26, normal = 4.27), and a low urinary osmolality (less than 400 mOsm/kg). From this study we conclude that an ATN of variable severity may be associated with the hepatorenal syndrome. Since this ATN developed without preceding shock, sepsis, or hypotension it is possible that this ATN like that in ischemic acute renal failure may be due to reduced renal blood flow and intense cortical vasoconstriction which has been reported in hepatorenal syndrome. Finally, our data imply that low urinary sodium is consistent with this pathologic lesion in this clinical setting.