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1

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An electron microscopic study of myofilament calcium binding sites in native, EGTA-chelated and calcium reloaded glycerolated mammalian skeletal muscle (1974)

Davis, Walter L. ; Matthews, J. L. ; Martin, J. H.

Springer

Calcified tissue international 14 (1974), S. 139-152

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ISSN: 1432-0827

Keywords: Sarcoplasmic Reticulum ; Myofilaments ; Troponin ; Pyroantimonate ; “Calcium Sink”

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Description / Table of Contents: Résumé L'ultrastructure du muscle squelettique de lapin est étudiée après traitement au glycérol et colgoration au pyroantimonate. Des dépôts denses aux électrons sont observés dans le reticulum sarcoplasmique restant. Ils sont associés aux myofilaments. Ces granules denses sont éliminés par chélation à l'EDTA et ces granules réapparaissent aux mêmes localisations après adjonction d'ions calcium au milieu d'incubation. L'existence de sites de liaisons spécifiques inter et intramyofibrillaires est ainsi confirmée. Les sites de liaison des myofilaments sont en rapport avec la longueur du sarcomère, étant donné que la localisation des granules est différente lorsque des sarcomères plus courts sont comparés à des sarcomères plus longs. Il semble que le calcium lié aux myofilaments joue un rôle essentiel au cours de la coordination et de la phase de repos de la contraction musculaire.

Abstract: Zusammenfassung Die Ultrastruktur des Skelettmuskels von Kaninchen wurde durch Einlegen in Glycerin und Färbung mit Pyroantimonat untersucht. Es wurden im residualen Sarkoplasma-Reticulum elektronendichte Ablagerungen beobachtet und mit Myofilamenten in Zusammenhang gebracht. Diese dichten Granula verschwanden durch Chelation mit EGTA, und neue Granula erschienen an denselben Stellen, wenn dem Inkubationsmedium Calciumionen beigegeben wurden. Auf diese Weise wurde das Auftreten spezifischer inter- und intramyofibrillärer Bindungsstellen bestätigt. Es wurde festgestellt, daß die Myofilament-Bindungsstellen von der Länge der Sarkomeren abhingen, denn die Verteilung der Granula war verschieden, wenn kürzere Sarkomeren mit längeren verglichen wurden. Es wird vorgeschlagen, daß das an Myofilamente gebundene Calcium eine wesentliche Rolle in der Kontraktion, der Verbinding und der Relaxation spielt.

Notes: Abstract The ultrastructure of rabbit skeletal muscle was studied following glycerolation and staining with pyroantimonate. Electron-dense deposits were observed within the residual sarcoplasmic reticulum and associated with myofilaments. These dense granules were removed by chelation with EGTA and granules reappeared at these same sites upon the addition of calcium ions to the incubation medium. Specific inter- and intra-myofibrillar binding sites were thus confirmed. Myofilament binding sites were found to be a function of sarcomere length, since the granule distribution was different when shorter sarcomeres were compared to longer sarcomeres. It is proposed that calcium bound to myofilaments plays an essential role in contraction coupling and relaxation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02060290

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The ultrastructural immunocytochemical localization of superoxide dismutase in the amphibian urinary bladder: Effect of aldosterone (1989)

Davis, Walter L. ; Kipnis, M. ; Shibata, K. ; [et al.]

Springer

Journal of molecular histology 21 (1989), S. 203-209

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Transmission electron microscopy and immunohistochemistry, the latter employing the avidin—biotin—peroxidase (ABC complex) technique, were utilized to localize copper—zinc superoxide dismutase (CuZn—SOD) enzyme activity in the epithelial cells of the toad urinary bladder mucosa. This ‘scavenger’ enzyme catalyses the dismutation (reduction—oxidation) of the superoxide anion (O2 −), a toxic free radical generated during normal cellular respiration. In unstimulated epithelial cells, enzyme activity was seen in the cytosol of granular, mitochondrial-rich and goblet cells. The basal cells were generally devoid of enzyme activity. In addition to the cytosol, SOD activity was also seen in association with the apical plasma membrane of the epithelial cells. In the presence of the steroid hormone aldosterone (10−7 m, 30 min—6 h), CuZn—SOD activity was markedly increased along the luminal mucosal membrane of granular, mitochondrial-rich and goblet cells. This increase was seen as early as 30 min after the addition of hormone, and as long as 6 h after treatment. The cytosolic reaction was usually decreased or absent under these conditions. From the data presented, it appears that CuZn—SOD is involved in electrolyte (sodium) transport in the epithelial cells of the toad urinary bladder. The latter may involve hormone-induced alterations in luminal cell membrane structure and chemistry.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01747521

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Superoxide formation preceding flight muscle histolysis in Solenopsis: fine structural cytochemistry and biochemistry (1993)

Davis, Walter L. ; Jacoby, Bennett H. ; Jones, Ruth G. ; [et al.]

Springer

Journal of molecular histology 25 (1993), S. 478-490

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary In Solenopsis spp., muscle histolysis or breakdown is a normal process in females and is initiated in the flight muscles only immediately after a mating flight. Information regarding the presence of the oxyradical scavenging enzyme superoxide dismutase (SOD) and the formation of the radical oxygen intermediate superoxide (SO) during the early stages of flight muscle histolysis in this insect was investigated. In normal fibrillar flight muscles from control animals, SOD was immunolocalized to vesicular and tubular components of the sarcotubular system. Lanthanum tracer studies indicated that some of these SOD-positive structures might be tubulovesicles continuous with the extracellular space. Following the injection of virgin alates with experimental haemolymph obtained from artificially inseminated females, the membrane delimited elements of the sarcotubular system became increasingly swollen and dilated with time (from 60 to 120 minutes postinjection) with a concomitant decrease in SOD activity and an increase in oxyradical formation. Many similar vesicles were lanthanum-positive. SO was not seen in the sarcoplasmic vesicles and tubules of control insects. The biochemical quantification of SO release over a 2-hour period showed a marked increase in oxyradical formation following treatment with the experimental haemolymph in comparison to control insects. Also, the addition of superoxide dismutase depressed SO formation under these conditions. Despite the histochemical and biochemical changes seen in the muscles of experimental insects, by 2 hours post-treatment there was no evidence of muscle necrosis. From these studies on flight muscle histolysis/necrosis in Solenopsis it appears that the formation of oxyradicals might represent an early event in myopathogenesis and subsequent tissue involution. The generation of SO is more than likely to be associated with alterations in the normal structure, biochemistry and permeability of the biomembranes which delimit the sarcotubular system.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00159283

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4

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Immunolocalization of ubiquitin in degenerating insect flight muscle (1994)

Davis, Walter L. ; Jacoby, B. H. ; Goodman, David B. P.

Springer

Journal of molecular histology 26 (1994), S. 298-305

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Ubiquitin was localized by immunofluorescence microscopy during post-mating histolysis of fibrillar flight muscle in female fire ants, Solenopsis spp. Normal muscles, as well as histolysing muscles from artificially inseminated and haemolymph-injected females contained ubiquitin in association with nuclei, Z-lines, myofilaments and mitochondria. However, the density of the ubiquitin immunoreaction was markedly increased in the nuclei, Z-lines and mitochondria of degenerating tissues 6, 12 and 24 h post treatment. At these times the heaviest immunoreactivity for ubiquitin was seen in association with the nuclei, Z-lines and mitochondria. Immuno-controls, incubated in the absence of the primary antibody, showed no similar immunostaining. When insemination was preceded by the injection of actinomycin D, muscle degradation was significantly depressed after a 24-h period. Also, ubiquitin immunofluorescence was markedly reduced in tissues pre-treated with actinomycin D. These observations suggest that insemination increases the ubiquitination of specific myofibrillar proteins destined for degradation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00157762

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5

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The immunohistochemical localization of superoxide dismutase activity in the avian epithelial growth plate (1989)

Davis, Walter L. ; Kipnis, M. ; Shibata, K. ; [et al.]

Springer

Journal of molecular histology 21 (1989), S. 210-215

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Superoxide dismutase (SOD) is a ‘scavenger’ enzyme which catalyses the dismutation (reduction—oxidation) of the superoxide anion (O2 −), a toxic free radical generated during normal cellular respiration. Light microscopy employing immunohistochemistry was utilized for localizing SOD activity in the chick epiphyseal cartilage. Antibodies to mammalian liver CuZn—SOD were prepared and the avidin—biotin—peroxidase technique (ABC complex) was utilized to localize activity for this enzyme in the growth plate cartilage. The localization of enzyme activity varied in accordance with the characteristic zonation pattern of the growth plate (zone of proliferation, zone of maturation, zone of cell hypertrophy and zone of matrix calcification). In the upper regions of the epiphyseal cartilage (the zones of proliferation and maturation), where the vascularity is poor and the oxygen tension low, SOD activity was localized within the chondrocytes. No extracellular activity was observed. However, in the lower regions of the growth plate (the zones of cell hypertrophy and matrix calcification), where both the vascularity and the oxygen tensions are increased, SOD activity was intense in both the chondrocytes and the surrounding extracellular matrix. Thus, the distribution of SOD enzyme activity in this tissue seems to vary in accordance with the level of oxygen present. The significance of the extracellular SOD activity, seen in the lower aspects of the growth plate cartilage, may indicate the sensitivity of matrix components, especially collagen, to toxic free radicals such as the superoxide anion.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01747522

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6

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The immunocytochemical localization of superoxide dismutase in the enterocytes of the avian intestine: The effect of vitamin D3 (1989)

Davis, Walter L. ; Matthews, James L. ; Shibata, K. ; [et al.]

Springer

Journal of molecular histology 21 (1989), S. 194-202

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ISSN: 1573-6865

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Both light microscopical and electron microscopical immunocytochemical techniques were utilized to localize CuZnsuperoxide dismutase (SOD) in the duodenum of normal, rachitic and vitamin-D3-replete chicks. This enzyme catalyses the dismutation of the superoxide anion, a toxic free radical generated during the normal aerobic metabolism of most respiring cells. Light microscopy showed no SOD activity associated with the duodenal enterocytes of normal and rachitic chicks. However, in rachitic animals subsequently treated with vitamin D, i.e. vitamin-D-replete chicks, intense immunoreactivity for the enzyme was seen in association with the apical border of the duodenal absorptive cells. Immunostaining for SOD was not seen in goblet cells. With electron microscopy, immunostaining for SOD activity was identified in association with the apical microvilli and, to a lesser degree, with the terminal web, a well as in association with both lysosomes and peroxisomes. From this report it appears that there is a physiological relationship between vitamin D, SOD and the intestinal absorptive cell. However, the precise relationship must await further clarification.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01747520

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7

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Electron-microscopic and morphometric study of vesiculation in the epithelial cell layer of the toad urinary bladder (1982)

Davis, Walter L. ; Gwendolyn Jones, Ruth ; Ciumei, John ; [et al.]

Springer

Cell & tissue research 225 (1982), S. 619-631

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ISSN: 1432-0878

Keywords: Amphibian (toad) urinary bladder ; Antidiuretic hormone (vasopressin) ; Vesiculation ; Hydroosmosis (water flow) ; Epithelia

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Basolateral vesicles are apparent in mitochondria-rich, granular and basal cells of the epithelium of unstimulated toad urinary bladder. Such vesicles are smooth-walled rather than coated. Because of the number of these vesicles, we decided to investigate the effect of arginine vasopressin (AVP) on this vesicle population during the hydroosmotic response. Both glutaraldehyde and glutaraldehyde-osmium tetroxide fixation procedures, as well as electron-microscopic morphometric techniques were utilized. Fifteen min after the administration of AVP in the presence of an osmotic gradient, the intracellular area occupied by basolateral vesicles was increased approximately threefold when compared to unstimulated control hemibladders (0.92±0.15% vs: 2.67±0.39 %). The intracellular nature of the majority of these vesicles was confirmed by experiments utilizing lanthanum as an electron-dense tracer. It is hypothesized that this vesicular activity may be involved in water movement across the tissue after hormone treatment.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00214808

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