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  • 1985-1989  (1,433)
  • 1975-1979  (715)
  • 1987  (1,433)
  • 1977  (715)
  • Cell & Developmental Biology  (1,935)
  • Ultrastructure  (218)
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  • 1985-1989  (1,433)
  • 1975-1979  (715)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of cells in the cambial region during winter hardening and spring dehardening in Salix dasyclados Wim. grown at two nutrient levels (1987)
    Springer
    Trees 1 (1987), S. 151-163 
    Details
    ISSN: 1432-2285
    Keywords: Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193558
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  • 2
    Electronic Resource
    Electronic Resource
    The fine structure of gliomatosis cerebri (1987)
    Springer
    Virchows Archiv 411 (1987), S. 93-98 
    Details
    ISSN: 1432-2307
    Keywords: Gliomatosis cerebri ; Brain tumour ; Ultrastructure ; Glial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural features of five biopsies of gliomatosis cerebri (GC) are described. Four main types of tumour cells are seen: anaplastic astrocytes poor in organelles with a variable amount of glial microfilaments; atypical oligodendrocytes with scanty cytoplasm in which microtubules are present; intermediate forms with aboundant cytoplasm rich in organelles, with microtubules and microfilaments; and small cells with round nuclei and a very scanty rim of cytoplasm. In two cases several concentrically folded cytoplasmic lamellae of glial processes were arranged either around themselves or around the perikaryon of other cells. This ultrasructural study indicates that GC is a neoplastic process of small undifferentiated elements, transitional forms of astroglia (to oligodendroglia) and anaplastic cells of astrocytic origin in all stages of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00734520
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  • 3
    Electronic Resource
    Electronic Resource
    The existance of rhabdoid cells in specified soft tissue sarcomas (1987)
    Springer
    Virchows Archiv 411 (1987), S. 509-514 
    Details
    ISSN: 1432-2307
    Keywords: Soft tissue neoplasm ; Sarcoma ; Rhabdoid cell ; Rhabdoid tumor ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the occurrence of rhabdoid cells in several specified soft tissue sarcomas of round cell variety. The rhabdoid cells had an acidophilic cytoplasm containing a globular perinuclear inclusion and were characterised ultrastructurally by the presence of aggregates of 10 nm intermediate filaments. These filaments contained both cytokeratin and vimentin, as demonstrated immunohistochemically. Extensive sampling of soft tissue sarcomas revealed the presence of such cells in different types of soft tissue round cell sarcomas as follows: 12 of 13 cases of epithelioid sarcomas, 8 of 13 synovial sarcomas (composed predominantly of round cells), 6 of 20 extraskeletal myxoid chondrosarcomas and 4 of 4 round celled malignant mesotheliomas. We wish to stress that the appearance of rhabdoid cells is not a monopoly of one particular type of tumour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713281
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  • 4
    Electronic Resource
    Electronic Resource
    Endothelial cilia in human aortic atherosclerotic lesions (1987)
    Springer
    Virchows Archiv 410 (1987), S. 317-326 
    Details
    ISSN: 1432-2307
    Keywords: “Primary” endothelial cilia ; Endothelial centrioles ; Human atherosclerosis ; Ciliary transitional fibers ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary “Primary” cilia were present in the endothelial cells of human aortic fatty dots and streaks but not in those of normal intima. They had the features of cilia of the “9+0” axonemal configuration observed in many other cells. A lateral foot process and transitional fibers “anchored” the ciliary basal body in the cytoplasm, but rootlets were not identified in material examined. Ladder-like configurations interconnected the two centrioles (=diplosome) of control endothelium. The “primary” cilia of endothelium differed from those of the rudimentary type observed in smooth muscle cells in similar lesions of man, but shared many features with cilia of those present in experimental atherosclerosis in rabbit. Cilia were rarely described in vascular endothelium. It is believed that, to date, they were not reported to occur in normal or pathological arteries in man. It is being stressed that whereas the significance of these unusual organelles remains uncertain, their widespread occurrence may indicate that their role is more important than was believed previously, and they should cease being a curiosity only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00711288
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  • 5
    Electronic Resource
    Electronic Resource
    Heterogeneity in a colonic carcinoid tumor (1987)
    Springer
    Virchows Archiv 410 (1987), S. 93-96 
    Details
    ISSN: 1432-2307
    Keywords: Heterogeneity ; Ultrastructure ; Colonic carcinoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report describes a colonic carcinoid tumor in which three, and possibly four, distinct cell types are distinguishable on the basis of their ultrastructure and granule morphology. These cell types closely resemble the normal endocrine cells of the large bowel, both in appearances and in relative frequency. The mixed composition of this tumor may have arisen either by parallel differentiation of distinct cell types, or by sequential maturation of one cell type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713510
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  • 6
    Electronic Resource
    Electronic Resource
    The effects of 16,16-dimethyl prostaglandin E2+aspirin on the canine gastric mucosal barrier (1987)
    Springer
    Virchows Archiv 412 (1987), S. 119-125 
    Details
    ISSN: 1432-2307
    Keywords: 16,16-dimethyl prostaglandin E2 ; Aspirin ; Tight junctions ; Stomach ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The canine gastric epithelium was exposed to solutions containing 20 mM aspirin and 20 mM aspirin + 30 µg/kg 16,16-dimethyl prostaglandin E2 (dmPGE2) for periods of three and forty minutes. No macroscopic hemorrhagic lesions were seen. Light microscopically, surface lesions were reduced from 10 percent (aspirin alone) to 2.5% (aspirin+dmPGE2). However, dmPGE2 does not appear to attenuate aspirin induced tight junction alterations. Discontinuities in the apical occluding complexes, hyperplastic tight junctions and stand number variability were documented in freeze frature replicas of aspirin as well as aspirin+ dmPGE2 treated dog stomachs. The results of these experiments would seem to suggest that 30 µg/kg dmPGE2 does not prevent aspirin induced damage to the tight junctions of the canine gastric epithelium or enhance their repair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716183
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  • 7
    Electronic Resource
    Electronic Resource
    Psammous desmo-osteoblastoma (1987)
    Springer
    Virchows Archiv 411 (1987), S. 561-568 
    Details
    ISSN: 1432-2307
    Keywords: Psammous desmo-osteoblastoma ; Ultrastructure ; Osteonectin ; Bone tumours ; Fibro-osseous lesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fibro-osteo-cemental lesions of the jaw bones are a heterogeneous group of diseases which present problems in classification. Psammous desmo-osteoblastoma is one of four newly proposed entities (Makek 1983) and has until now been characterized by its light microscopic, clinical and radiological features. On electron microscopy this tumour exhibits fibroblastic (preosteoblastic), osteoblastic and osteocytic cells and a globular mineralization unlike the mineralization of the psammoma bodies. Immunohistological investigations with anti-osteonectin, a bone specific protein linking mineral to collagen, showed positive intracellular staining in all tumour cells and extracellular staining in the osteoid. The psammoma bodies were, however, not stained. These results confirm the view of the osteogenic histogenesis of psammous desmo-osteoblastoma, with an osteogenic differentiation of the tumour cells, bone formation and association of psammoma bodies which are not of bone origin. This combination of findings supports the view that psammous desmo-osteoblastoma represents a new and distinct entity occuring in desmal preformed cranio-facial bones which should be incorporated in a revised WHO-classification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713287
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  • 8
    Electronic Resource
    Electronic Resource
    Endocrine cells in ectocervical epithelium (1987)
    Springer
    Virchows Archiv 411 (1987), S. 293-298 
    Details
    ISSN: 1432-2307
    Keywords: Ectocervix ; Serotonin cells ; Calcitonin cells ; Ultrastructure ; Transitional epithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A systematic study of endocrine cells in the ectocervix was carried out using histochemical, immunohistochemical and ultrastructural techniques. Serotonin and calcitonin immunoreactive cells were demonstrated in this site. Serotonin and calcitonin immunoreactivities were coexpressed in the same endocrine cell. These distinctive cells were encountered in two main morphological varieties of ectocervical epithelium. Normal-appearing stratified squamous epithelium contained only very rare serotonin and calcitonin cells. In contrast, endocrine cells were fairly abundant in a specific epithelium termed “transitional-like”. This type of epithelium was not only confined to the transformation zone but could also extend onto the portio as far as the vaginal cut margin. In some cases, transitional-like epithelium bore morphological resemblance to urothelium. In other cases, it could be regarded as basal cell hyperplasia or immature squamous metaplasia. Of interest, serotonin and calcitonin cells have been well-documented as normal inhabitants of some other non-squamous epithelia, such as urothelium or pseudostratified columnar epithelium. Therefore, it is suggested that certain ectocervical epithelia show some similarities to urothelium, in respect of their morphological appearance and endocrine profile. Further investigations using more objective and specific markers of urothelial cells are needed to assess the exact degree of homology connecting all these types of epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00735036
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  • 9
    Electronic Resource
    Electronic Resource
    Some ultrastructural features of the myocardial cells in the hypertrophied human papillary muscle (1987)
    Springer
    Virchows Archiv 410 (1987), S. 281-294 
    Details
    ISSN: 1432-2307
    Keywords: Human heart ; Papillary muscle ; Myocardial hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study using various electron microscopical techniques has been conducted on biopsy material from the hypertrophied papillary muscle of the human heart. About 75% of the myocardial cells were classified as hypertrophic with diameters ranging from 15 εm to 53 εm. The increased cell diameter appeared to be the result of an elevated amount of mitochondria and contractile material. The hypertrophied myocytes displayed a general ultrastructural organization in many ways similar to that of the normal sized myocytes. However, the former cells were characterized by focal deposits of excess laminar coat material and abnormal Z-band patterns as well as of multiple intercalated discs. The preferential sites for the production of new sarcomere elements appeared to be in the subsarcolemmal and intercalated disc regions. Adjacent myocardial cells were interconnected by collagen bundles, and, by an elaborate collagen-fibril-microthread-granule lattice. The surface folds were linked to each other by surface cables, which probably constituted a separate category of extracellular material of unknown function. Intramembranous particles were abundant in the sarcolemma proper but scarce in the membranes of the sarcoplasmic vesicles. Such particles were also observed in the lipofuscin granular membrane and in the membranes surrounding the lipid droplets. A framework of transverse cytoskeletal filaments interconnected the Z-bands of adjacent myofibrils and anchored the contractile material to the sarcolemma as well as to the nucleus. A large and lobulated nucleus containing well developed nucleoli together with an abundance of sarcoplasmic free and membrane-attached ribosomes, were interpreted as morphological signs of enhanced synthetic activity in the hypertrophied cell. Degenerative phenomena on the other hand were confined to lysosomal degeneration of worn-out cell constituents that were manifested by the numerous lysosomes and aggregates of lipofuscin granules. Abnormal Z-band patterns as seen in the present material were interpreted as an initial stage in the formation of new contractile elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00711285
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  • 10
    Electronic Resource
    Electronic Resource
    Ectopic anterior pituitary corticotropic tumour in a six-year-old boy (1987)
    Springer
    Virchows Archiv 411 (1987), S. 267-273 
    Details
    ISSN: 1432-2307
    Keywords: Corticotropic adenoma ; Ultrastructure ; Pituitary oncocytoma ; Choroid Plexus carcinoma ; Mitochondrial morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The report documents a silent, oncocytic, ACTH-producing ectopic anterior pituitary tumour in a 6-year-old boy. The invasive intrahemispheric neoplasm had no connection with the pituitary gland, the sella turcica or the sphenoid sinuses. The apparent similarities existing between this tumour, some choroid plexus carcinomas and steroid-producing neoplasms are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00735033
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructure of tumour invasion and desmoplastic response of bronchogenic squamous cell carcinoma (1987)
    Springer
    Virchows Archiv 411 (1987), S. 283-291 
    Details
    ISSN: 1432-2307
    Keywords: Tumor invasion ; Ultrastructure ; Desmoplasia ; Squamous cell carcinoma ; Lung parenchyma ; Basal lamina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using ultrastructural methods we studied the interaction of tumour cells and lung parenchyma in deep areas (i.e., more than about 3 mm from the tumour surface) of 50 bronchogenic squamous cell carcinomas. The tumour periphery, studied previously, had shown organized associations of tumour cells and lung epithelial cells and a surprising lack of invasion of non-epithelial tissue compartments. The deeper areas, where the tumour cells and the lung parenchyma had been in contact for longer periods, consisted of irregular groups of tumour cells and desmoplastic stroma which was very similar to granulation tissue. The deeper areas also contained many intact lung epithelial cells, arranged in compressed and distorted alveolar structures. Where non-neoplastic epithelial cells and tumour cells had direct contact, they formed common junctional complexes and basal laminae. In part of the tumours, the cells were largely devoid of a basal lamina. However, in most instances a continuous basal lamina surrounded every tumour cell group studied, even when these formed irregular strands or seemed to be completely isolated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00735035
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  • 12
    Electronic Resource
    Electronic Resource
    Mixed crypt cell carcinoma (1987)
    Springer
    Virchows Archiv 412 (1987), S. 175-182 
    Details
    ISSN: 1432-2307
    Keywords: Appendix ; Colorectal neoplasm ; Carcinoid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinicopathological features of six appendix and five bowel tumours with features of the so-called ‘goblet cell carcinoid’ are described. By light microscopy, these tumours were composed predominantly of mucous cells, together with variable proportions of endocrine and Paneth cells. Immunohistochemical and ultrastructural study confirmed this impression and no amphicrine cells were seen. The clinical course of all cases arising in the bowel, and three out of six appendix tumours was characterised by an aggressive behaviour with the development of widespread lymphatic and often intraperitoneal metastasis, but liver metastasis occurred in only one instance. We conclude, both from this study and from a review of the literature, that the ‘mixed crypt cell carcinoma’ forms a distinct clinicopathological entity justifying separate classification from adenocarcinoma and carcinoid tumour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716191
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  • 13
    Electronic Resource
    Electronic Resource
    Ultrastructure of human preovulatory granulosa cells in follicular fluid aspirates (1987)
    Springer
    Archives of gynecology and obstetrics 240 (1987), S. 137-146 
    Details
    ISSN: 1432-0711
    Keywords: Preovulatory granulosa cells ; Call-Exner body ; Fibrin ; Human ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of preovulatory granulosa cells may be distinct in follicles containing competent as opposed to non-competent oocytes. To test this assumption, granulosa cells were looked for in 36 follicular fluid aspirates from 8 patients taking part in an in vitro fertilization and embryo transfer program. Granulosa cells were absent from 16 aspirates and present in 20. Both aspirate types contained oocytes able to develop in culture. Granulosa cells were subdivided into three developmental stages. Stage 1 (5% of aspirates) showed proliferating cells, while stage 2 (60% of aspirates) and 3 (35% of aspirates) cells were in the preluteinization stage. These cells were recognizable by their number of lipid droplets and differentiated according to possession of a rough (stage 2) or smooth (stage 3) endoplasmic reticulum. Luteinization did not occur in these cells. All stages displayed desmosomes, gap junctions, and annular junctions. The structure of Call-Exner bodies and of fibrin deposits were unexpected findings. Our study indicates that there is no correlation between the previously used morphological parameters of granulosa cells and oocyte maturity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207708
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  • 14
    Electronic Resource
    Electronic Resource
    Silver affects viability and structure of cultured mouse peritoneal macrophages and peroxidative capacity of whole mouse liver (1987)
    Springer
    Archives of toxicology 59 (1987), S. 408-412 
    Details
    ISSN: 1432-0738
    Keywords: Silver toxicity ; Cultured macrophages ; Cell death ; Ultrastructure ; Lipid peroxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of silver on cultured mouse peritoneal macrophages were examined by estimation of cell survival and by light and electron microscopy. Additon of silver lactate to the culture medium at final concentrations of 40 and 80 μM resulted in coagulation necrosis and rapid cell death. At lower concentrations cell structure appeared normal. However, the rate of cell death at 20 μM silver lactate was increased as compared to controls. Silver, visualized by physical development/autometallography, was invariably located in lysosomes. The production of malondialdehyde in mouse liver of silver-treated mice as compared to controls was also examined. This lipid peroxidation product had increased to the same amount in animals treated with silver for either 3 days or with only one silver injection 4 h before examination. This study has demonstrated that silver affects viability and structure of cultured macrophages, possibly due to induction of lipid peroxidation, as demonstrated to occur in the liver of silver-exposed mice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316206
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  • 15
    Electronic Resource
    Electronic Resource
    Ultrastructural alterations of neuronal cells in a brain stem ganglioglioma (1987)
    Springer
    Acta neuropathologica 74 (1987), S. 307-312 
    Details
    ISSN: 1432-0533
    Keywords: Ganglioglioma ; Neuronal degeneration ; Ultrastructure ; Brain stem ; Brain tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A brain stem ganglioglioma in a 9-year-old female was examined ultrastructurally. The constituent neuronal (ganglion) cells displayed various ultrastructural features of neuronal degeneration including Hirano, Lafora and zebra bodies, inclusion-like aggregates of neurofilaments and large dilatations of rough endoplasmic reticulum. Although similar observations have been reported in peripheral neuronal tumors, this is the first reported occurrence in ganglioglioma, an uncommon tumor in the central nervous system. The coincidence of these alterations in the present tumor appeared to be of great interest, however, their exact etiology remained uncertain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688197
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  • 16
    Electronic Resource
    Electronic Resource
    Glial filaments in the subcutaneous tumors of mouse glioma clones differently expressing glial fibrillary acidic protein (1987)
    Springer
    Acta neuropathologica 74 (1987), S. 1-8 
    Details
    ISSN: 1432-0533
    Keywords: Intermediate filaments ; Glial fibrillary acidic protein (GFAP) ; Vimentin ; Ultrastructure ; Glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glial filaments contain vimentin and glial fibrillary acidic protein (GFAP). The question of how glial filaments change morphologically according to the expression of vimentin and/or GFAP has remained unclear. In this study, immunohistochemical and ultrastructural examinations were performed on the subcutaneously transplanted tumors of two clones (F6B3 and G10A10) derived from a mouse glioma. F6B3 tumor expressed GFAP and vimentin in large quantities. G10A10 tumor expressed plenty of vimentin but only a little of GFAP. Ultrastructurally, F6B3 tumor contained abundant cytoprocesses in most of which numerous intermediate filaments (IFs) were arranged in a parallel array. On the other hand, only a small number of the processes were seen in G10A10 tumor, which showed a few IFs arranged either randomly or sparsely in the processes. Both tumors commonly had the IFs accompanied by visible sidearms, but there was a difference in that the smooth and firm IFs were confined to part of F6B3 tumor. Thus, the comparison made between the two models presented differences in the content, arrangement and morphology of IFs, as well as in the manner of GFAP expression, suggesting correlation between these differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688331
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  • 17
    Electronic Resource
    Electronic Resource
    The ultrastructure of the nervous tissue in a benign teratoma (1987)
    Springer
    Acta neuropathologica 73 (1987), S. 281-286 
    Details
    ISSN: 1432-0533
    Keywords: Teratoma ; Nervous tissue ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the nervous tissue in a benign ovarian teratoma is described. This tissue was organized into areas having both “meningel” and “ependymal” surfaces, between which were found astrocytes, ependymal cells, neurones with synapses and microglia. These cells all had ultrastructural similarities to their normal counterparts in the nervous system. In addition, some signs of degenerative change — due possibly to the abnormal location of the nervous tissue — were observed. Oligodendrocytes and myelin were absent, possibly because of vascular insufficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686623
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  • 18
    Electronic Resource
    Electronic Resource
    Esthesioneuroepithelioma: a tumor of true olfactory epithelium origin (1987)
    Springer
    Acta neuropathologica 75 (1987), S. 147-155 
    Details
    ISSN: 1432-0533
    Keywords: Esthesioneuroepithelioma ; Ultrastructure ; Immunohistochemistry ; Neurofilament protein (NFP) ; Keratin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of esthesioneuroepithelioma was investigated ultrastructurally and immunohistochemically, using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), keratin, neuron-specific enolase (NSE), S-100 protein (S-100), and tyrosine hydroxylase (TH). The tumor initially manifested as an epidural mass in the anterior cranial fossa in a 64-year-old man, and about 31/2 years later, autopsy further revealed extensive metastases to the lymph nodes of the neck and thoracic cavity. In the cranial and nasal cavities, the tumor was composed of fairly uniform, ill-defined cells arranged in nests which were surrounded by a fibrovascular stroma. These histological features were reproduced in the metastatic tumor nodules with frequent occurrence of tubular arrangements of the tumor cells. Ultrastructurally, two different cell types were well recognized by their characteristic morphological features, which were reminiscent of sensory neurons and sustentacular cells of the olfactory epithelium. No dense-cored secretory granules were observed in the tumor cells. Immunohistochemically, the tumor showed a variable number of cells positive for NFP, keratin, NSE and S-100. NFP was present in a relatively small number of cells, which were found diffusely in the nests. Keratin was observed in the cells mainly located at the periphery. NSE-positive cells tended to form irregular clusters in the center. A few S-100-positive cells were found, without any particular arrangement. These findings indicated that the present tumor, which actually arose in the superior nasal cavity, consisted of cells differentiating in at least two distinct directions, neuronal and epithelial, and strongly suggested that the tumor was of true olfactory epithelium origin, or more precisely, derived from the bipotential, undifferentiated basal cells of this epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687075
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  • 19
    Electronic Resource
    Electronic Resource
    Light and electron microscopic immunohistochemical studies of serotonin nerve fibers in the substantia nigra of the rat, cat and monkey (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 13-18 
    Details
    ISSN: 1432-0568
    Keywords: Serotonin ; Substantia nigra ; Mammals (rat, cat, Macaca fuscata) ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of serotonin-containing nerve fibers in the substantia nigra of the rat, cat and monkey was studied with a highly sensitive peroxidase-antiperoxidase immunohistochemical method. Serotonin fibers in the substantia nigra of all species consisted of fine varicose fibers and formed a fine network. In the zona compacta of all species, serotonin fibers were sparsely distributed. In the zone reticularis of the rat and cat, these fibers were densely distributed and their distributional pattern was almost uniform, while in the monkey such fibers were unevenly distributed and high and low dense areas were intermingled. In the pars lateralis of all species, serotonin fibers were diffusely distributed, and the distributional density was much higher in the cat and monkey than in the rat. Immunoelectron-microscopic studies further revealed that a majority of the labeled varicosities in the rat substantia nigra were in close apposition to peridendritic axon terminals and were also free in the neuropil; occasionally they exhibited symmetrical synapses of “en passant” type with non-immunoreactive dendrites or somata. Our results support a functional significance of serotonergic regulation of the substantia nigra in mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309747
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  • 20
    Electronic Resource
    Electronic Resource
    Bovine cumulus-oocyte disconnection in vitro (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 41-44 
    Details
    ISSN: 1432-0568
    Keywords: Bovine ; Oocyte maturation ; Meiosis ; Gap junction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were obtained from cows by aspiration of small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and processed for transmission electron microscopy after different periods of culture including a 0 h control group. In 0 h control oocytes the cumulus cells had numerous projections which penetrated the zona pellucida and established gap junctions with the oolemma. A partial loss of these junctions was noticed as an early event of oocyte maturation occurring within the first 3 h of culture. A low frequency of gap junctions was maintained until 12–18 h of culture where the junctional contact was completely disrupted. This decrease in intercellular communication was parallelled by resumption of oocyte meiosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309750
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    Electronic Resource
    Ultrastructure of the final nuclear maturation of bovine oocytes in vitro (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 35-40 
    Details
    ISSN: 1432-0568
    Keywords: Bovine ; Oocyte maturation ; Meiosis ; Nucleus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were obtained from cow ovaries by aspiration from small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and subsequently processed for electron microscopy after various periods of culture. By morphological criteria the oocytes could be divided into the following sequence of meiotic stages. The oocyte nucleus I stage was characterized by a spherical nucleus located peripherally in the ooplasm while undulation of the nuclear envelope and initial chromatin condensation was seen at the oocyte nucleus II stage. The oocyte nucleus breakdown stage was characterized by formation of long slender projections from the nuclear envelope in which the envelope doubled back on itself, appearance of dense areas and haphazardly oriented microtubules in the nucleus, marked condensation of the chromatin, and dissolution of the nuclear envelope into irregular vesicles and tubules. The condensed chromatin I stage was characterized by the location of condensed chromatin configuration and uniformly oriented microtubules in a dense area peripherally in the ooplasm while the final condensed chromatin II stage was characterized by a gradual invasion of condensed chromatin configurations into a dense area combined with the presence of the first polar body in the perivitelline space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309749
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  • 22
    Electronic Resource
    Electronic Resource
    Effects of all-trans retinoic acid on the morphology of human epidermal cells in vitro (1987)
    Springer
    Archives of dermatological research 279 (1987), S. 459-464 
    Details
    ISSN: 1432-069X
    Keywords: All-trans retinoic acid ; Epidermal cells ; Ultrastructure ; Differentiation ; Stratification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of all-trans retinoic acid on human epidermal cell cultures were studied using ultrastructural techniques. Differentiation and stratification were reduced in retinoic acid treated epidermal cells. Treated cells developed a rounded appearance and seemed to contain more granules and vacuoles than usual. Desmosomes were not found in treated cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00412592
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  • 23
    Electronic Resource
    Electronic Resource
    New ultrastructural changes of the ependyma in experimental hydrocephalus (1987)
    Springer
    Acta neuropathologica 73 (1987), S. 400-402 
    Details
    ISSN: 1432-0533
    Keywords: Ultrastructure ; Ependyma ; Experimental hydrocephalus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary New ultrastructural alterations of the ependymal cells in the altered container model of experimental feline hydrocephalus are described. These include half desmosomes and a basal lamina on the apical surface of the ependymal cells, punctate adhesion-like structures between intraventricular mononuclear cell and the apical surface of the ependymal cells and unusual distortion of the ependymal cells. The significance of these previously unreported morphological alterations is unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688267
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  • 24
    Electronic Resource
    Electronic Resource
    Ultrastructural and ionic studies in global ischemic dog brain (1987)
    Springer
    Acta neuropathologica 73 (1987), S. 393-399 
    Details
    ISSN: 1432-0533
    Keywords: Brain ; Global ischemia ; Ultrastructure ; Ionic changes ; Ca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A time course of tissue ionic changes, and their relation to ultrastructural findings during reperfusion following a 15-min global ischemic brain insult was studied in a dog model. Parietal cortex was analyzed for Ca, Na, K, Mg and Fe in controls and after 10 min, 2, 4, and 8 h of reperfusion. After 8 h of reperfusion, the mean values (μmol/g tissue wet wt.) for Ca (control=1.43, 8 h=2.76) and Na (control 60.4, 8 h=107.4) doubled and K (control=90.4, 8 h=48.5) decreased to half that of the control. Ultrastructural studies and subcellular localization of calcium in parietal cortex of in situ-fixed brains after 8 h showed cortical neurons with clumping of nuclear chromatin, dilatation of endoplasmic reticulum and disruption of plasma membranes. Large amounts of electron-dense precipitates of calcium were present within dilated astrocytic processes, synaptic vesicles, cytoplasm of edematous dendrites and mitochondria. Cortical neurons from postischemic dogs without reperfusion showed only slight chromatin clumping and edema of astrocytic processes, but no calcium accumulation. The large ionic shifts noted between 4 and 8 h of reperfusion, indicate a progressive inability of the cells to maintain normal transmembrane gradients of these ions and may reflect a membrane destructive process, as demonstrated ultrastructurally at 8 h. Enhanced calcium entry into the neuron during reperfusion appears to be a part of the cytotoxic mechanism leading to neuronal necrosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688266
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  • 25
    Electronic Resource
    Electronic Resource
    The ultrastructure of early implantation in the marmoset monkey (Callithrix jacchus) (1987)
    Springer
    Anatomy and embryology 175 (1987), S. 399-410 
    Details
    ISSN: 1432-0568
    Keywords: Implantation ; Marmoset ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural morphology of the initial stages of implantation in the marmoset monkey (Callithrix jacchus) was studied in pregnant monkeys at known time intervals after ovulation. The earliest samples, obtained 13 days after ovulation, displayed both cytotrophoblast and syncytiotrophoblast. The cytotrophoblast was restricted to the blastocoel, whilst syncytiotrophoblast intruded to the endometrial basal lamina. At later stages, days 16 and 19 after ovulation, both cytotrophoblast and syncytiotrophoblast had extended laterally around the uterus, and the syncytiotrophoblast also extended deeper into the maternal tissnes. The mesoderm layer was first discernible at 19 days after ovulation. At 23 days after ovulation the syncytiotrophoblast surrounded the maternal blood vessels entirely. In this study syncytiotrophoblast was not observed to breach the maternal blood vessels, even at 31 days after ovulation. Early cytotrophoblast columns could be seen at 31 days after ovulation. The endothelial cells lining the maternal blood vessels displayed hypertrophy from the earliest stages (day 13) onwards, although a true decidual response was only observed in samples of 23 and 31 days after ovulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309853
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  • 26
    Electronic Resource
    Electronic Resource
    An investigation of pulp capillaries and tight junctions between odontoblasts in cats (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 131-138 
    Details
    ISSN: 1432-0568
    Keywords: Capillaries ; Tooth pulp ; Tight junctions ; Odontoblasts ; Ultrastructure ; Mineralisation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative roles of capillaries and odontoblasts in the process of dentinogenesis and in pulp reactions to trauma and pathology are not clear. Contributing to the problem is the paucity of information on odontoblast —capillary relationships and tight junctions between odontoblasts. Using light microscopy the capillaries have now been examined in semithin transverse sections of perfusion fixed teeth at different positions in the long axis from the apical foramina to the pulp horns. Odontoblastic capillaries were prominent in the coronal and middle regions of canines and present at the same levels of incisors. In the pulp horns and just coronal to the pulp horns capillaries were all subodontoblastic but near the apex there were also a few odontoblastic capillary profiles. Transmission electron microscopy on ultrathin sections revealed that a high proportion of middle and coronal odontoblastic capillary profiles were fenestrated but subodontoblastic profiles coronal to the pulp horns were the most fenestrated. In a search for tight junctions in ultrathin sections some typical strands were observed between odontoblasts. The difficult of obtaining the latter evidence was explained by the cellular arrangement of the odontoblasts which differed markedly from an ideal parallel, apically coplanar arrangement. The results question the possibility that there is a direct exchange of materials between pulp capillaries and dentine in teeth of limited growth and provide a baseline for future experiments to test the permeability of the odontoblast layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572537
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  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructure of a two-cell human embryo (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 91-96 
    Details
    ISSN: 1432-0568
    Keywords: Ultrastructure ; Human egg ; Human embryo ; Cleavage embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A two-cell human embryo recovered from the Fallopian tube 82 h following the LH peak in plasma and 37 h after a single episode of intercourse was examined by transmission electron microscopy. At the time of recovery the embryo was denuded of cumulus cells, and both the zona pellucida and the two adjoining blastomeres were intact. The finding of two polar bodies in the perivitelline space, two nucleated blastomeres and remnants of the fertilizing sperm tail within the cytoplasm of one of them, were considered as evidences that the embryo was normally fertilized. Among the most compicuous features found were the presence of very distinct desmosome-like structure between blastomeres, and the cytoplasmic cell organelles distribution in three areas referred as: a sub-cortical, a middle and a perinuclear bands. An outstanding feature was the extensive blebbing of the nuclear envelope. In general, the features seem to correspond to a normally developing two-cell embryo undergoing cleavage at a normal rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325292
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  • 28
    Electronic Resource
    Electronic Resource
    Effects of vagotomy on the ultrastructure of the atrial myocardium in the monkey (Macaca fascicularis) (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 147-152 
    Details
    ISSN: 1432-0568
    Keywords: Atrial myocardium ; Vagotomy ; Monkey ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the atrial myocardium in the monkey (Macaca fascicularis) was studied after bilateral cervical vagotomy and survival times of 1, 3, 5, 7, 10, 21 and 28 days. During the first week after vagotomy, a few atrial cells showed a reduction in the sarcoplasm, crowding of the myofibrils, peripheral dispersion and reduced intercristal density of the mitochondria and increased sarcoplasmic reticulum and glycogen particles. In some profiles, there was increased electron density and granularity at the I bands and the intercalated discs. The number of such affected cells increased in the subsequent days such that by 21 to 28 days about 50% of the cells were estimated to be affected. During the latter stages further changes included, the degradation of the myofilaments and increased electron density, disorganisation and disintegration of the digital extensions at the intercalated discs. Throughout the experiments there was a leucocytic infiltration, more evident in the longer survival times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572539
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  • 29
    Electronic Resource
    Electronic Resource
    Relative position of constitutive heterochromatin and of nucleolar structures during mouse spermiogenesis (1987)
    Springer
    Anatomy and embryology 175 (1987), S. 467-475 
    Details
    ISSN: 1432-0568
    Keywords: Mouse spermiogenesis ; Constitutive heterochromatin ; Nucleolus organizing regions ; Fluorochrome ; Staining ; EM silver staining ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, the selective fluorochrome staining of constitutive heterochromatin and a specific ultrastructural silver-staining of nucleolar material (i.e., the nucleolus organizing regions) were undertaken to be used as indicators for the chromosomal arrangement during mouse spermiogenesis. Since in mice all somatic chromosomes are telocentric and the constitutive heterochromatin and nucleolar organizing regions are closely associated to the centromeres, this combination of techniques provided for the first time ultrastructural evidence 1) for the dispersion of the constitutive heterochromatic chromocentre and a centrifugal migration to the postacrosomal portion of the nuclear envelope where constitutive heterochromatin seems to mediate the assembling of microtubules in the so-called manchette. As elongation continues, the constitutive heterochromatin migrates back into central position and forms the “focous of earlier condensing chromatin”, which initiates further chromatin condensation. 2) The fate of the nucleolus during spermiogenesis could also be further clarified: The nucleolus is first associated with the chromocentre, but starts to disintegrate during elongation phase. However, argyrophilic remnants are still visible in the centre of the nucleus, pointing to an ongoing transcriptional activity. When they final disappear, they leave behind “nuclear vacuoles” in the dense chromatin mass of the mature sperm nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309682
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  • 30
    Electronic Resource
    Electronic Resource
    Mesenchymal tissue of the interventricular septum (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 231-237 
    Details
    ISSN: 1432-0568
    Keywords: Embryonic chick heart ; Interventricular septum ; Mesenchymal tissue ; Endocardial activation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28–29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process. The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310056
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  • 31
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    Electronic Resource
    The human muscle-tendon junction (1987)
    Springer
    Anatomy and embryology 176 (1987), S. 281-294 
    Details
    ISSN: 1432-0568
    Keywords: Myotendinous junction ; Human growth ; Skeletal muscle ; Tendon ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The myotendon junction of human paravertebral skeletal muscle was studied by light and electron microscopy. Transverse and longitudinal sections of myotendinous regions of normal multifidus muscles were examined at three chronological stages from birth to maturity. Variations in the appearance of surface extensions at the terminal ends of muscle fibers consisted of brush-like evaginations at birth and villous-like projections in the adult. Regardless of age, they were invariably covered by a prominent external lamina, and mutually interdigitated with connectivetissue elements in the adjacent tendon. Various stages of myofibrillar assembly and sarcomere alignment were evident in the muscle fiber terminus at birth. With advancing age, splitting of terminal sarcomeres at Z bands commonly gave rise to diverging myofilament bundles that attached to electron-dense patches under the sarcolemma. In these regions, leptomeric organelles were also encountered in neonatal and adolescent myotendons. At all stages, the ends of muscle fibers possessed cytological features consistent with active synthesis and secretion. Densely-packed sarcoplasmic organelles including multiple Golgi complexes, clusters of ribosomes, mitochondria, cytoplasmic vesicles, and elements of rough- and smooth-surfaced endoplasmic reticulum were prevalent. Peripheral and centrally-placed heterochromatic nuclei with prominent nucleoli were arranged singly or in groups at the ends of muscle fibers. Satellite cell profiles and unmyelinated axons in the subjacent tendon were also identified at these sites in the adult. Fibroblasts in growing tendon were plentiful, and at all stages, possessed morphological features indicative of high metabolic and secretory activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310184
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    Electronic Resource
    A case of adult neuronal ceroid-lipofuscinosis with the appearance of membranous cytoplasmic bodies localized in the spinal anterior horn (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 362-368 
    Details
    ISSN: 1432-0533
    Keywords: Neuronal ceroid-lipofuscinosis ; Membranous cytoplasmic body ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An autopsy case of adult neuronal ceroid-lipofuscinosis was examined. The clinical picture was charaterized by gait disturbance, bulbar palsy and dementia. Histopathologically, diffuse neuronal loss was found throughout the central nervous system. The remaining neurons, predominantly in the motor nuclei of the spinal cord and brain stem, were swollen with storage material. Observed under the electron microscope the storage material showed various ultrastructures, such as lipofuscin-like bodies, pleomorphic lipid bodies, curvilinear profiles and finger-print profiles, in different regions of the central nervous system. In the ballooned neurons of the spinal anterior horn, many membranous cytoplasmic bodies and curvilinear profiles were intermingled within the same cell and were continuous with each other. Biochemically,N-acetyl neuraminic acid content was significantly increased in the spinal anterior horn. These findings suggest the localized increase of ganglioside in that region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687268
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  • 33
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    Electronic Resource
    Vesicle formation and cellulose degradation in Bacteroides succinogenes cultures: ultrastructural aspects (1987)
    Springer
    Archives of microbiology 148 (1987), S. 150-154 
    Details
    ISSN: 1432-072X
    Keywords: Bacteroides ; Vesicles ; Ultrastructure ; Cellulolytic bacteria ; Rumen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 3-day-old cultures of Bacteroides succinogenes grown on filter paper, no cell division was observed. When grown on cellulosic substrate, bacteria exhibited vesicles clustered within cell wall pockets. In 2 day-old filter paper cultures, cells adhered tightly to the substrate. Twenty to 30% of them were dividing. There were cell wall pockets in about 25% of the bacteria, but no vesicles. Whether they adhered to the cellulosic substrate or not, and irrespective of the age of the bacteria, storage polysaccharides were found in the form of dense granules in the cytoplasm. It would appear that vesicles are not essential for cellulose degradation, but are rather a sign of ageing of the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425364
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  • 34
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    Electronic Resource
    Early persistent UVA-pigmentation: Ultrastructural and morphometric analyses (1987)
    Springer
    Archives of dermatological research 279 (1987), S. 173-179 
    Details
    ISSN: 1432-069X
    Keywords: UV-A pigmentation ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary UV-A-induced skin pigmentation was investigated morphologically in semithin and thin sections from 11 volunteers, using different irradiation modalities (single doses of 10,50 and 100 J/cm2). Visible skin pigmentation was observed in all but two probands, and erythema in two; pronounced pigmentation was present after repeated irradiation only. Contralateral non-irradiated, UV-B-irradiated and suntanned skin specimens were used as controls. There was an increase in the number of clear cells in the basal layer (x 1.6) and particularly of large clear cells (x 1.7) after repeated irradiation. Also, the number of melanosomes in melanocytic dendrites (x 2.8) increased after repeated irradiation. The number, size and shape of the melanosome complexes in both basal and suprabasal keratinocytes remained unchanged, even when a distinction was made between central and peripheral location. In contrast, suntanned skin showed an increase in melanosome complexes in basal (x 5.8) and suprabasal (x 3.7) keratinocytes. It is concluded that UV-A-induced skin pigmentation differs in some ways from UV-B or sun-induced melanogenesis, and that the clinical grade of tanning cannot accurately be determined by ultrastructural methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413253
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  • 35
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    Electronic Resource
    The sequence of ultrastructural changes in cultured neurons after dendrite transection (1987)
    Springer
    Experimental brain research 67 (1987), S. 41-51 
    Details
    ISSN: 1432-1106
    Keywords: Trauma ; Neuron ; Culture ; Calcium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cultured mouse spinal neurons were fixed at three different intervals after dendrite amputation: within the first 15 min, at 2 h and at 24 h. Dendrites were amputated at lesion distance of either 50 μm (31% probability of cell survival) or 100 μm (53% probability of cell survival) from the edge of their perikarya. When fixed within 15 min, operated neurons showed a two-phase gradient of ultrastructural damage which spread from the transection site towards the perikaryon. At 2 h after dendrite amputation all neurons operated close to their perikarya were categorized as either viable, moribund or dead, based on their appearance with phase contrast microscopy. These categories of response to physical trauma corresponded to distinctly different ultrastructural changes. Moribund neurons were filled with membrane-bound vesicles which were derived from swollen mitochondria and grossly dilated cisternae of the smooth endoplasmic reticulum. The cytoplasm of dead neurons contained large clear areas and many condensed, dark mitochondria. Both moribund and dead neurons lacked cytoskeletal elements. All of these ultrastructural changes are hypothesized to be the result of an increase in the intracellular concentrations of free calcium. Although evidence of residual mitochondrial swelling was present in some surviving neurons at 24 h, the ultrastructure of others was comparable to that of control cells. Some surviving neurons had terminal swellings at the ends of the severed neurites which were very similar to retraction balls of transected axons after CNS trauma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269451
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    Electronic Resource
    Membranes during yolk-platelet development in oocytes of the toad Bufo marinus (1987)
    Springer
    Development genes and evolution 196 (1987), S. 367-371 
    Details
    ISSN: 1432-041X
    Keywords: Vitellogenesis ; Bufo marinus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Oocytes of the toad Bufo marinus have been studied by means of thin section and particularly freeze-fracture electron microscopy to characterize the cytoplasmic membranes around the yolk organelle, and the storage of yolk material in precursors and platelets. This appears to be a previously unknown type of yolk-platelet formation. During yolk-organelle development from the primordial precursor to the bi-partite fully grown yolk platelet, numerous lipoid droplets are attached to the periphery of the platelet, indicating an intense uptake of lipids. As is typical for amphibians, the fully grown yolk platelet has a crystalline internum covered by a dense osmiophilic externum, and the whole organelle is enveloped by a plasma membrane that shows no direct connection or fusion with endocytotic vesicles. The yolk membrane exhibits few intramembraneous particles (IMPs) at the core areas and some more where it borders fields of lipoid droplets. Here the IMPs show a net-like arrangement in the furrows between adjacent droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375773
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  • 37
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    Electronic Resource
    Morphology and ultrastructure of 11 barley shrunken endosperm mutants (1987)
    Springer
    Theoretical and applied genetics 74 (1987), S. 177-187 
    Details
    ISSN: 1432-2242
    Keywords: Barley ; Grain development ; Mutants ; Ultrastructure ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 3∶1 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00289966
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  • 38
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    Electronic Resource
    Damage and repair of the immature rat cerebellum after cis-dichlorodiammineplatinum II (cis-DDP) treatment. An ultrastructural study (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 218-228 
    Details
    ISSN: 1432-0533
    Keywords: Cerebellum ; Histogenesis ; Cisdichlorodiammineplatinum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this electron microscopy study was to further investigate the effects of cis-dichlorodiammineplatinum (cis-DDP) on the cerebellum of the immature rat. Ten-day-old animals were treated with cis-DDP subcutaneously and killed after 1, 7, 15 or 21 days. On postinjection day 1, cis-DDP effects were evident mainly in the external granular layer, with nuclear damage in many dividing cells, while their cytoplasm appeared to be less affected. Some binucleate cells were also present. On the contrary, in postmitotic or more differentiated cells, only cytoplasmic alterations were found. At later stages (postinjection day 7), the frequency of damaged cells in the external granular layer decreased, but there was a cellular deficit in the internal granular layer. Many postmitotic neurons underwent coagulative necrosis. Finally (postinjection days 15 and 21), the cellular deficit was partly compensated for by “reactive” structures, e.g., glial cell fibers, which underwent hypertrophy after initial edema. Moreover, packing densities of Bergmann astrocytes and oligodendrocytes were higher.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691093
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  • 39
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    Electronic Resource
    Periphery of ethylnitrosourea-induced spinal gliomas in rats with special reference to the vascular structure (1987)
    Springer
    Acta neuropathologica 73 (1987), S. 92-98 
    Details
    ISSN: 1432-0533
    Keywords: Spinal gliomas ; Vascular proliferation ; Ethylnitrosourea ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histology and ultrastructure of ten spinal cord gliomas, mainly oligodendrogliomas, induced transplacentally in rat with ethylnitrosourea were studied. The characteristic feature of seven spinal tumours was distinct delineation of neoplastic tissue from the edematous surrounding zone by a ring of irregular, proliferating capillaries, among which immature capillary buds prevailed. The alterations were proliferation of endothelium with endothelial overlapping, elongation of interendothelial junctions and enhancement of pinocytotic vesicles on luminal and abluminal surfaces. The basal membranes, besides other changes, were often replaced by some floccular condensations. In the edematous zone the capillary walls were deprived of contact with glial processes. The lack of contact between astrocytic processes and vascular wall may contribute to the persistent immature state of peripheral capillaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695507
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    Electronic Resource
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    Surface morphology of the perfused rabbit ovary (1987)
    Springer
    Archives of gynecology and obstetrics 240 (1987), S. 33-43 
    Details
    ISSN: 1432-0711
    Keywords: Ovary ; Surface epithelium ; Perfusion ; Rabbit ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using transmission electron microscopy we examined the morphology of the surface epithelium of the isolated and perfused rabbit ovary after an ovulatory dose of HCG. Rupture of follicles occurred in vitro approximately 13 h after HCG-injection and 6 h after the start of perfusion. The ultrastructural changes during the perfusion were similar to those occurring in vivo. The perfused ovarian epithelium had villous processes of varied architectural complexity with squamoid and cuboid epithelial cells. The superficial cells contained pinocytotic vesicles, coated and noncoated endocytotic caveolae, and occasional vacuoles. Dense bodies were more commonly found in vitro than in vivo. Occasionally structures similar to “Call-Exner-bodies” were found on the surface epithelium near to preovulatory follicles. Intercellular spaces of various sizes were also numerous. Disappearance of surface epithelium in the apex of follicles was often observed and the matrix of the tunica albuginea consisted of dissociated fibers and degenerating cells. This study showed that the isolated perfused rabbit ovary can serve as a model for studying the biology and pathology of ovarian surface epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02134062
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    Electron microscopy studies of human intestinal spirochetes (1987)
    Springer
    European journal of epidemiology 3 (1987), S. 187-195 
    Details
    ISSN: 1573-7284
    Keywords: Human intestinal spirochetes ; Swine intestinal treponemes ; T. hyodysenteriae ; T. innocens ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of twenty human intestinal spirochetes was analyzed using the electron microscope. Negatively stained cells were generally found to be loosely and irregularly waved. The isolates had cell dimensions ranging from 0.12–0.35 μm in width and from 3.9–14.2 μm in length. Twin bundles of flagella were present in the space between the cytoplasmic membrane and the outer membrane. The majority of isolates had five flagella inserted sub-terminally at each cell end. Human intestinal spirochetes divide by binary fission. They are morphologically similar to swine intestinal treponemes, both pathogenic (Treponema hyodysenteriae) and non pathogenic (Treponema innocens), and different from Treponema pallidum, Treponema phagedenis and Borrelia burgdorferi. Following treatment with sodium deoxycolate, no bundles of cytoplasmic microtubules were observed in cells obtained from cultures of human and swine intestinal spirochetes or from cells of B. burgdorferi, while these structures were present in similarly treated cells of T. pallidum and T. phagedenis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239758
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    Changes in carbohydrates and ultrastructure in xylem ray cells ofPopulus in response to chilling (1987)
    Springer
    Protoplasma 137 (1987), S. 45-55 
    Details
    ISSN: 1615-6102
    Keywords: Carbohydrates ; Chilling effects ; Populus ; Sugars ; Ultrastructure ; Xylem ray cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of xylem ray cells inPopulus was studied in conjunction with their content of individual sugars and of starch. They differ considerably in structure and in carbohydrate content at the three chosen stages,i.e., of starch deposition (August), of starch maximum (November), and of starch dissolution (January). The transition from the summer to winter stage was also induced experimentally by storage of tissue at 0°C. Both in nature and after cold-storage, sucrose and its galactosides raffinose and stachyose were accumulated to a great extent, contributing up to 69.7 and 57.3% of total sugar content, respectively. They originated parallel to the breakdown of starch and to the appearance of abundant vesicular and dilated ER cisternae. Results indicating that they are the specific sites of sucrose accumulation, and/or its galactosides, are discussed. The occurrence of phytoferritin-like crystalloids in amyloplasts and of vacuolar flocculent material, which condenses into electron-dense bodies of suspectedly proteinaceous nature, is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281175
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    Ultrastructure ofCatharanthus roseus cells culturedin vitro and exposed to conditions for alkaloid accumulation (1987)
    Springer
    Protoplasma 140 (1987), S. 157-163 
    Details
    ISSN: 1615-6102
    Keywords: Alkaloid production ; Catharanthus roseus ; Plant cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Periwinkle (Catharanthus roseus) cells cultured in 1-B 5 medium display the ultrastructure of parenchyma cells. The parenchyma character remained unchanged when cells were exposed to any one of three different conditions effecting alkaloid accumulation. Transfer of cells to “alkaloid production medium” for 2 weeks (condition 1) accorded two special features,i.e., unusually big lipid droplets in the cytoplasm and, upon fixation, one or several electron-dense droplets of spongy precipitate in vacuoles. Among hormone-autotrophic cultures (condition 2) some cells showed a fine electron-dense vacuolar precipitate. Addition ofPhythium homogenate (fungal elicitor) to cells cultured in 1-B 5-medium for 10 days (condition 3), cells showed a frequent appearance of singular big lipid droplets in the cytoplasm, whereas vacuoles remained devoid of precipitate. The appearance of big lipid droplets and of vacuolar precipitate is interpreted as progressing cytodifferentiation, but is coincidental with alkaloid accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273725
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  • 44
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    Alisma embryogenesis: The development and ultrastructure of the suspensor (1987)
    Springer
    Protoplasma 137 (1987), S. 71-83 
    Details
    ISSN: 1615-6102
    Keywords: Alisma ; Embryogenesis ; Endopolyploidy ; Suspensor differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of the suspensor (consisting of a basal cell and a few chalazal cells) inAlisma plantagoaquatica andA. lanceolatum was investigated using cytochemical methods, light and electron microscopy. The basal cell becomes differentiated during the first three days of embryo development. As a result of endopolyploidization the volume of the nucleus rapidly increases, as does the quantity of chromatin it contains and the size of the nucleolus. As basal cell grows, its cytoplasm increases in volume and the number of organelles increase, and wall ingrowths begin to form on the walls at the micropylar pole of the cell. The full development and functioning of the suspensor occurs during the next three days. The enormous basal cell then attains its maximum degree of differentiation: its nucleus reaches a ploidy of 256n or 512n, the micropylar transfer wall is fully developed, as is the cytoplasm, rich in proteins, ribonucleic acids (RNA) and organelles, particularly dictyosomes and long cisternae of the rough endoplasmic reticulum. The chalazal suspensor cells joining the embryo proper to the basal cell also become differentiated. In the seven-day embryo the suspensor begins to degenerate which coincides with the cellularization of the endosperm at the micropylar pole of the embryo sac. The senescence of the suspensor involves the degradation of the nucleus, increasing cytoplasmic vacuolization, and a distinct decrease in protein and RNA content, first in the basal cell, then in the chalazal suspensor cells. Analysis of the development and ultrastructure of the basal suspensor cell suggests that it plays the role of an active metabolic transfer cell, translocating nutrients from the maternal tissues via the chalazal suspensor cells to the growing embryo proper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281143
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    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070201
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    Substructure of sidearms on squid axoplasmic vesicles and microtubules visualized by negative contrast electron microscopyPart of this work was performed at the Marine Biological Laboratory, Woods Hole, MA 02543. (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 20-30 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present a high-resolution electron microscopic study of the sidearms on microtubules and vesicles that are suggested to form the crossbridges which produce the microtubule-based vesicle transport in squid axoplasm. The sidearms were found attached to the surfaces of the anterogradely transported vesicles in the presence of ATP. These sidearms were made of one to three filaments of uniform diameter. Each filament measured 5-6 nm in width and 30-35 nm in length. The filaments in some of the sidearms had splayed apart by pivoting at their base, thereby assuming a “V” shape. The spread configuration illustrated the independence of the individual filaments. The filaments in other sidearms were closely spaced and oriented parallel to each other, a pattern called the compact configuration. In axoplasmic buffer containing AMP-PNP, structures indistinguishable from the filaments of the sidearms on the vesicles were observed attached to microtubules. Pairs of filaments, thought to represent the basic functional unit, were observed attached to adjacent protofilaments of the microtubules by their distal tips. These data support a model of vesicle movement in which a pair of filaments within a sidearm forms two crossbridges and moves a vesicle by “walking” along the protofilaments of the microtubule.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970070104
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    Polymorphic assembly of subtilisin-cleaved tubulin (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 31-38 
    Details
    ISSN: 0886-1544
    Keywords: microtubule assembly ; proleolysis ; Vinca drugs ; Zn2+-induced assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Limited proteolysis of tubulin with subtilisin results in cleavage of both the α and β subunits, releasing small peptides from the C-terminal ends. At 37°C the digested tubulin assembles into polymorphic structures: microtubules with attached ribbons in the presence of GTP, rings in the presence of GDP, and protofilament spirals in the presence of vinblastine. Undigested tubulin does not assemble under these conditions. Rings and Vinca-induced spiral structures are assembled from undigested tubulin only when microtubule-associated proteins, high Mg2+ concentrations, or polycations are present. Thus, cleavage with subtilisin affects assembly in a manner similar to the addition of these agents. It appears that binding of positively charged substances may act by neutralizing the charge on the highly acidic C-terminal regions of the α- and β-subunits, while cleavage with subtilisin produces the same effect by removing these peptides. Undigested and subtilisin-digested tubulin form sheets of protofilaments in the presence of Zn2+, which indicates that the binding sites for the 2-3 Zn2+ ions necessary to induce sheet formation do not reside in the C-terminal regions of the monomers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070105
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  • 48
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    Wave of cortical actin polymerization in the sea urchin egg (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 46-53 
    Details
    ISSN: 0886-1544
    Keywords: actin filament ; fertilization ; fluorescent labeled phallotoxins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution of actin filaments in the cortical layer of sea urchin eggs during fertilization has been investigated by light microscopy using fluorescently labeled phallotoxins. The cortical layer of both whole eggs and cortices isolated on a glass surface was examined. In cortices of unfertilized eggs, numerous fluorescent spots were seen, which may correspond to short actin filament cores in microvilli. After insemination, one of the sperm-attaching points on the egg surface first became strongly fluorescent. This fluorescence grew around the point of sperm penetration with the growth of the fertilization cone. Then, the cortical layer of the egg around the fertilization cone became strongly fluorescent and the fluorescence propagated in a wavelike manner over the entire cortex. The mechanism of the propagation of actin polymerization is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070107
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    Comparison of the beating of cis- and trans-flagella of Chlamydomonas cells held on micropipettes (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 87-93 
    Details
    ISSN: 0886-1544
    Keywords: movement ; flagellar ; beat, flagellar ; stigma ; high-speed microcinematography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chlamydomonas cells sucked onto micropipettes were filmed at 500 frames/sec and analyzed as to their forward beating mode. A comparison with freely swimming cells revealed that the flagella of the sucked cells beat in a normal threedimensional manner, with beat frequencies that correspond to those of freely swimming cells. Most beats were synchronous. but not symmetrical; cis- and trans-flagellum appear to beat in a slightly different manner. Some cells beat synchronously throughout, but mostly synchrony was interrupted by a single asynchrony or up to incessant asynchronies, caused by transient accelerations of the trans- (fo-) flagellum. Only rarely did cis- and trans-flagella have different but constant beat frequencies. Helical swimming of Chlamydomonas more likely is due to the beat asymmetries of the two flagella than to differences of beat frequencies. In our records, the stigma is on the inside of the helical swimming path.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070111
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  • 50
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    A unique tubulin antibody which disrupts particle movement in squid axoplasm (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 110-115 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; antitubulin ; particle translocalion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules have been demonstrated to be a substrate for organelle transport and particle translocation in vitro and in vivo. Subsequent to a previous report of inhibition of axonal transport of exogenous tracers in vivo using antiserum NS-20 against tubulin (Johnston et al: Brain Res. 1986), we now show disruption of particle movement in extruded squid axoplnsm using this unique immunological probe. Using video-enhanced contract-differential interference contrast (AVEC-DIC) microscopy, we examined the properties of particle movement along microtubules and demonstrated that bolh the velocity of particle movement and the numbers of particles moving are decreased in the presence of NS-20 antiserum or NS-20 affinity-purified antibodies but. not in the presence of another antiserum against tubulin. The amount of microtubule substrate does not change in the presence of any of the antisera. In conclusion, we suggest that NS-20 antibodies bind near or at a site on the tubulin molecule which is critical in the mechanism of particle transport, and provide a direct immunological probe to examine the mechanism of microtubule involvement in axonal transport.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070203
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    Massive actin bundle couples macrocilia to muscles in the ctenophore Beroë (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 116-128 
    Details
    ISSN: 0886-1544
    Keywords: actin filament bundle ; macrociliary cell ; Clenophores ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Macrocilia are thick compound ciliary organlles arising individually from elongated epithelial cells on the lips of beroid ctenophores. A giant wedge-shaped bundle of microfilaments extends 25-30 μm from the base of each macrocilium to the lower end of the cell, terminating at a junction with an underlying smooth muscle cell. The broad end of the microfilament bundle is anchored to the macrocilium by striated rootlet fibers that extend from the basal bodies into the bundle and are linked to the microfilaments by periodic bridges. Fluorescence microscopy of rhodamine-phalloidin stained intact tissue, dissociated macrociliary cells, and Triton/glycerol-isolated bundles shows that the microfilaments contain actin. The microfilaments run generally parallel to the long axis of the bundle but are not highly ordered. Filaments decorated with myosin S1 show a uniform polarity with arrowheads pointing away from the tapered membrane-associated end of the bundle. No variations in bundle length (nor changes in rootlet periodicity) were observed in tissue fixed under conditions of calcium activation. Isolated bundles did not contract in Mg-ATP, even though detached macrocilia underwent reactivated beating and sliding disintegration. Macrocilia arc used to bite through food organisms or transport prey into the stomach. The actin filament bundles probably play a supporting role as a structural linker between macrocilia and subepithelial muscle fibers and may serve as intracellular tendons lo mechanically coordinate the motor activities of macrocilia and muscles during prey ingestion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070204
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    Translational control and the cytoskeleton in Physarum polycephalum (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 129-137 
    Details
    ISSN: 0886-1544
    Keywords: actin mRNA ; sclerotium ; polysomes ; Triton X-100 extraction ; cycloheximide ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Translationally active plasmodia of the syncytial slime mold Physarum polycephalum develop into translationally dormant sclerotia during starvation. Although functional mRNA and ribosomes exist in sclerotia, protein synthesis is suppressed at the level of initiation. To test the possibility that alterations in the cytoskeleton may limit protein synthesis, we have examined the distribution of polysomes and actin mRNA in the cytoskeletal (CSK) and soluble (SOL) fractions of Triton X-100-extracted plasmodia and sclerotia. Most of the polysomes and actin mRNA were located in the CSK of plasmodia, while most of the ribosomes and actin mRNA were located in the SOL of sclerotia. The results suggest that ribosomes and mRNA shift from the CSK to the SOL as protein synthesis is suppressed during starvation. Plasmodia and sclerotia can be induced to accumulate excess polysomes by treatment with low levels of the elongation inhibitor cycloheximide. Treatment of plasmodia with cycloheximide caused excess polysomes to accumulate in the SOL, suggesting that the CSK contains a limited capacity for binding translational components and that the association of polysomes with the cytoskeleton is not required for protein synthesis. Treatment of sclerotia with cycloheximide, however, caused polysomes and actin mRNA to accumulate in the CSK, suggesting that the selcrotial cytoskeleton, although depleted in ribosomes and mRNA, is capable of binding translational components. It is concluded that alterations in the sclerotial cytoskeleton are not involved in translational control.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070205
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    cAMP-mediated inhibitory effect of calmodulin antagonists on ciliary reversal of ParameciumA part of this work was presented as a poster session at the 3rd International Congress on Cell Biology, Tokyo, 1984. (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 154-159 
    Details
    ISSN: 0886-1544
    Keywords: calcium ; protein phosphorylation ; TFP ; Triton-extracted model ; ciliary orientation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To explore possible roles of calmodulin in Ca2+-induced ciliary reversal, we tested the effects of calmodulin antagonists on Triton-extracted models of Paramecium. In the extracted models prepared by the method of Naitoh and Kaneko [Science 176:523-524, 1972], the Ca2+ -induced ciliary reversal was not inhibited by calmodulin antagonists, trifluoperazine (TFP), or 5-chloro-l-naphthalenesulphone amide (W-7). However, in the presence of adenosine 3′,5′-cyclic mono-phosphate (cAMP), whose concentration is below the one that alters the ciliary direction, TFP inhibited ciliary reversal and the models swam forward at 10-5 M Ca2+. When the washing medium in the preparation of the extracted models was replaced with one containing MgCl2, the extracted model showed sensitivity to calmodulin antagonists without addition of cAMP; at 10-5 M Ca2+, 40 μM TFP or 100 μM W-7 inhibited the ciliary reversal and the models swam forward. Such effect of antagonists was abolished by an inhibitor of cAMP-dependent protein kinase. On the other hand, addition of cAMP enhanced the inhibitory effect of antagonists. These results suggest that calmodulin antagonists act to increase the extent of cAMP-dependent protein phosphorylation that inhibits the Ca2+ -induced ciliary reversal.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070207
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    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070301
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    Reversible inhibition of microtubuies and cell growth by the bicyclic colchicine analogue MTC (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 178-186 
    Details
    ISSN: 0886-1544
    Keywords: colchicine binding ; tubulin ; immunofluorescence ; PtK2 ; Pk15 ; SV-3T3 cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 2-methoxy-5-(2,3,4-trimethoxyphenyl) 2,4,6-cycloheptatrien-1-one (MTC) is a synthetic colchicine analogue, lacking the B ring of the alkaloid (Fitzgerald: Biochem. Pharmacol. 25:1381-1387, 1976). MTC has been shown to bind reversibly to the colchicine binding site of tubulin and to inhibit microtubule assembly in vitro (Andreu et al: Biochemistry 23:1742-1752, 1984; Bane et al: J. Biol. Chem. 259:7391-7398, 1984). Its action on different cultured cell lines (PtK2, Pk15, and SV-3T3) has now been studied. 0.2 × 10-6 M MTC stopped Pkl5 and SV-3T3 cell growth, inducing an accumulation of mitoses in a few hours. Removal of MTC from the culture medium rapidly restored normal mitotic index and growth rates. Partial depolymerization of the cytoplasmic microtubules of PtK2 cells was observed at concentrations ranging from 2 to 5 × 10-7 M. Maximal microtubule network depolymerization was obtained after 4 h of treatment with 2 to 5 × 10-6 M MTC or at a higher MTC concentration (2 × 10-5 M) for less than 2 h. Removal of 2 × 10-5 M MTC (the highest MTC concentration used) from the culture medium resulted in almost complete microtubule polymerization after 10 min of drug recovery and a normal microtubule network in 20-30 min.MTC constitutes an antimitotic drug directed to the colchicine site. It is water-soluble, shows a fast and reversible action, and may therefore be employed as a convenient tool to study cellular microtubule-dependent functions.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970070210
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  • 56
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    Structural and chemical characterization of isolated centrosomes (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 238-249 
    Details
    ISSN: 0886-1544
    Keywords: human lymphoblastoma cells ; microtubule organizing centers ; isolation centrioles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A procedure adapted from that described by Mitchison and Kirschner [Nature 312:232-237, 1984] was used to isolate centrosomes from human lymphoid cells. High yields of homogeneous centrosomes (60% of the theoretical total, assuming one centrosome per cell) were obtained. Centrosomes were isolated as pairs of centrioles, plus their associated pericentriolar material. Ultrastructural investigation revealed: 1) a link between both centrioles in a centrosome formed by the gathering in of a unique bundle of thin filaments surrounding each centriole; 2) a stereotypic organization of the pericentriolar material, including a rim of constant width at the proximal end of each centriole and a disc of nine satellite arms organized according to a ninefold symmetry at the distal end and; 3) an axial hub in the lumen of each centriole at the distal end surrounded by some ill-defined material.The total protein content was 2 to 3 × 10-2 pg per isolated centrosome, a figure that suggests that the preparations were close to homogeneity. The protein composition was complex but specific, showing proteins ranging from 180 to 300 kD, one prominent band at 130 kD, and a group of proteins between 50 and 65 kD. Actin was also present in centrosome preparations.Functional studies demonstrated that the isolated centrosomes were competent to nucleate microtubules in vitro from purified tubulin in conditions in which spontaneous assembly could not occur. They were also very effective at inducing cleavage when microinjected into unfertilized Xenopus eggs.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080305
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  • 57
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    Association of intermediate filaments with vinculin-containing adhesion plaques of fibroblasts (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 274-283 
    Details
    ISSN: 0886-1544
    Keywords: focal contacts ; vimentin filaments ; microtubules ; immunofluorescence ; platinum replicas ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Double immunofluorescence staining of quail embryo fibroblasts with rabbit antibody to vinculin and mouse monoclonal antibody to vimentin revealed a coincidence between fluorescence patterns for cell-substrate focal contacts and intermediate filaments. Most of the vinculin-containing adhesion plaques coincided with the ends of vimentin-positive fibrils.This association was further corroborated by immunoelection microscopic observations of the cytoskeletons of quail and mouse fibroblasts using a platinum replica technique. The intermediate filaments were identified either by direct treatment with antivimentin IgM or by an indirect immunogold staining method.Colcemid treatment of the cells caused a collapse of intermediate filaments and destroyed their association with focal contacts. During the early stages of the colcemid-induced collapse of the intermediate filaments, single vimentin fibrils appeared to retain their association with focal contacts.The possible role of the intermediate filaments in the formation and maintenance of focal contacts is discussed.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080308
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    Acetylated and detyrosinated α-tubulins are co-localized in stable microtubules in rat meningeal fibroblasts (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 284-291 
    Details
    ISSN: 0886-1544
    Keywords: tyrosination ; acetylation ; post-translational modifications ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the distribution of acetylated α-tubulin using immunofluorescence microscopy in fibroblastic cells of rat brain meaninges. Meningeal fibroblasts showed heterogenous staining patterns with a monoclonal antibody against acetylated α-tubulin ranging from staining of primary cilia or microtubule-organising centers (MTOCs) alone to extensive microtubule networks. Staining with a broad spectrum anti-α-tubulin monoclonal indicated that all cells possessed cytoplasmic microtubule networks. From double-labeling experiments using an antibody against acetylated α-tubulin (6-11B-1) and antibodies against either tyrosinated or detyrosinated α-tubulin, it was found that acetylated α-tubulin and tyrosinated α-tubulin were often segregated to different microtubules. The microtubules containing acetylated but not tyrosinated α-tubulin were cold stable. Therefore, it appeared that in general meningeal cells possessed two subset of microtubules: One subset contained detyrosinated and acetylated α-tubulin and was cold stable, and the other contained tyrosinated α-tubulin and was cold labile. These results are consistent with the idea that acetylation and detyrosination of α-tubulin are involved in the specification of stable microtubules.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080309
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    Stimulation of in vitro motility of Chlamydomonas axonemes by inhibition of cAMP-dependent phosphorylation (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 302-311 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When demembranted axonemes of Chlamydomonas were reactivated with Mg ATP, the proportion of motile axonemes was significantly increased by the preence of either phosphodiesterase (PDE) or protein inhibitor of cAMP-dependent kinase (PKI). The effect of PDE was cancelled by the addition of cAMP. These findings strongly suggest that the axoneme samples have endogenous cAMP, which can reduce the proportion of motile axonemes via phosphorylation. This inhibitory effect of cAMP on Chlamydomonas axonemes is opposite to its stimulatory effect on the axonemal motility in other organisms so far reported. PKI or PDE activated the motility motility either in the absence of Ca2+, when the axonemes beat with an asymmetric waveform, or in 10-5M Ca2+, when the axonemes beat with a symmetric waveform. This cAMP-dependent regulation of motility was observed with the axonemes from which detergent-soluble material had been removed, indicating that the proteins responsible for the regulation still remained in the axonemes. Preliminary in vitro phosphorylation stdies have implicated two polypetides as candidates for the target protein of cAMP-dependent protein kinase: one with a molecular weight of 270 kD and the other with a much larger molecular weight.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080403
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    Binding and distribution of fluorescently labeled filamin in permeabilized and living cells (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 345-359 
    Details
    ISSN: 0886-1544
    Keywords: alpha-actinin ; cytoskeleton ; muscle cells ; nonmuscle cells ; stress fiber ; myofibril ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study report the first development of a fluorescently labeled filamin. Smooth muscle was labeled with fluorscent dyes in order to study its interaction with stress fibers and myofibrils, both in living cells and in permeabilized cells. The labeled filamin bounds to the Z bands of isolated cross-striated myofibrils and to the Z bands and intercalated discs in both permeabilized embryonic cardiac myocytes and in frozen sections of adult rat venticle. In permeabilized embryonic chick myotubes, filamin bound to early myotubes but was absent at later stages. In living embryonic chick myotubes, the fluorescently labeled filamin was incorporated into the Z bands of myofibirls during early and late stages of develoment but was absent during an intermediate stages. In living cardiac myocytes, filamin-IAR was incorporated into nascent as well as fully formed sarcomeres throughout develoment. In permeabilized nonmuslce cells, labeled filamin bound to attachment plaques and foci of polygonal networks and to the dense bodies in stress fibers. The periodic bands of filamin in stress fibers had a longer spacing in fibroblasts than in epithelial cells. When injected into living cells, filamin was readily incorporated into stress fibers in a striated pattern. The fluorescent filamin bands were broader in injected cells, however, than they were in permeabilized cells. We have interpreted these results from living and permeabilized cells to mean that native filamin is distributed along the full lengh of the actin filaments in the stress fibers, with a higher concentration present in the dense bodies. A sarcomeric model is presented indicating the position of filamin with respect to other proteins in the stress fibers.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080407
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    Frequency and orientation of pseudopod formation of Dictyostelium discoideum amebae chemotaxing in a spatial gradient: Further evidence for a temporal mechanism (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 18-26 
    Details
    ISSN: 0886-1544
    Keywords: chemotaxis ; cell motility ; cellular polarity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Amebae of Dictyostelium discoideum normally chemotax to aggregation centers by assessing the direction of outwardly moving, nondissipating waves of the chemoattractant cAMP. However, D. discoideum amebae can also assess the direction of a relatively stable spatial gradient. We demonstrate that amebae migrating towards the “source” of a stable, spatial gradient move faster, extend fewer pseudopodia, and turn less frequently than amebae migrating away from the “source” in the same spatial gradient. In addition, amebae extend lateral pseudopods in a polarized fashion from the anterior half of the cell, and do so as frequently towards the source as away from the source. However, those formed towards the source more often produce a turn than those formed away from the source. These results suggest that there may be two decision-making systems, one localized in the pseudopods, and one along the entire cell body; they support the suggestion that Dictyostelium amebae may employ a temporal mechanism to assess the direction of a spatial gradient of chemoattractant.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080104
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    Endoplasmic microtubules connect the advancing nucleus to the tip of legume root hairs, but F-actin is involved in basipetal migration (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 27-36 
    Details
    ISSN: 0886-1544
    Keywords: nuclear migration ; microtubules ; F-actin ; root hairs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A prominent feature of tip growth in filamentous plant cells is that the nucleus often migrates in step with the tip as it extends. We have studied this long-recognized but unexplained relationship in root hairs of the legume Vicia hirsuta by a variety of microscopic techniques. Using rhodaminyl lysine phallotoxin, and antitubulin antibodies, root hairs are shown to contain axial bundles of F-actin and a complex microtubular system. To the basal side of the nucleus the microtubules are cortical and net axial but in the region between nucleus and tip the arrangement is more complicated. Electron microscopic thin sections demonstrate that internal bundles of microtubles exist in addition to the plasma membrane-associated kind. Computerized deblurring of through-focal series of antitubulin stained hairs clarifies the three-dimensional organization: bundles of endoplasmic microtubules progress from the nuclear region toward the apical dome where they can be seen to fountain out upon the cortex.The relationship between nucleus and tip can be uncoupled with antimicrotubule herbicides. Time lapse video microscopy shows that these agents cause the nucleus to migrate toward the base. This contrary migration can be inhibited by adding cytochalasin D, which fragments the F-actin bundles.It is concluded that microtubules connect the nucleus to the tip but that F-actin is involved in basipetal migration as is known to occur when symbiotic bacteria uncouple the nucleus from the tip.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080105
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    Isolation and initial biochemical characterisation of caps of two major rat thymocyte glycoprotens: Evidence for the involvement of a 205 K Con A binding protein and cytoskeletal components in capping (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 37-43 
    Details
    ISSN: 0886-1544
    Keywords: capping ; concanavalin A ; glycoprotein ; membrane-cytoskeletal interactions ; thymocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two major rat thymocyte surface glycoproteins, the leucocyte-common (L-C) antigen and the leucocyte sialoglycoprotein (LSGP), were induced to cap independently, using the specific monoclonal antibodies OX-1 and W3/13, respectively, and an appropriate fluorescently labeled second antibody layer. The caps were subsequently isolated from detergent extracted cells by a procedure involving gentle shearing.TRITC-phalloidin staining of the isolated caps demonstrated the presence of F-actin within these structures, and lectin-affinity staining after fractionation on SDS polyacrylamide gels revealed the presence of a concanavalin A (Con A) binding protein of relative molecular weight (Mr) 205,000, gp205, in both the L-C antigen and LSGP caps, but absent from the detergent-insoluble residue isolated from unchallenged cells. These results suggest that gp205 may be involved in the association of cross-linked glycoproteins with the cytoskeleton during capping.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080106
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    Characterization of the intermediate filament apparatus in skin fibroblasts from patients with giant axonal neuropathy: Effect of trypsin (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 55-60 
    Details
    ISSN: 0886-1544
    Keywords: vimentin ; hereditary disease ; proteolysis ; serum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Skin fibroblasts from two siblings with giant axonal neuropathy (GAN) were examined by both biochemical and immunocytochemical studies. The presence of intermediate filaments (IF) characteristic of these cells was affected by the growth conditions. Immediately after plating and during the following 24 hours the majority of the cells contained an IF “bundle”; however, after 4-6 days in culture only a minority of the cells retained this structure. We present evidence that trypsinization but not serum concentration is likely to influence the formation of the “bundle.” The results indicate that the formation of the “bundle” may result from a defective association or relationship between the cytoskeleton and the plasma membrane.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080108
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    Protein phosphorylation and dynamics of cytoskeletal structures associated with basal bodies in Paramecium (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 44-54 
    Details
    ISSN: 0886-1544
    Keywords: monoclonal antibody ; phosphoproteins ; basal bodies ; morphogenesis ; Paramecium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The presence of phosphorylated proteins associated with microtubule organizing centers in tissue culture cells during mitosis has been demonstrated by the use of monoclonal antibodies raised against mitotic HeLa cells [Vandre et al., Proc. Natl. Acad. Sci. U.S.A. 81:4439-4443, 1984]. We report here that in Paramecium two of the mitosis specific antibodies, MPM-1 and MPM-2, decorate throughtout the cell cycle all the microtubule organizing centers (MTOCs) located in the cortex and in the oral apparatus (gullet). Immuno-electron microscopy showed that these antibodies labeled the electron-dense material surrounding basal bodies from which several microtubule networks as well as kinetodesmal fibers originate. During mitosis, these antibodies also stained other cortical cytoskeletal structures, the kinetodesmal fibers (MPM-1 and MPM-2) and the epiplasm (MPM-1). Among the different polypeptides recognized by the antibodies on immunoblots, three major ones of 60, 63, and 116 kDa were found to be common to the cortex (where several thousand ciliary basal bodies are anchored) and the oral apparatus (which comprises several hundred basal bodies around which various arrays of cytoplasmic microtubules are organized). Alkaline phosphatase treatment abolished the immunoreactivity of the polypeptides and the labeling observed by immunofluorescence. These results demonstrate that phosphorylated proteins are associated with all the known active microtubule organizing centers present in the cortex throughout the cell cycle of Paramecium. Furthermore they indicate that in Paramecium phosphorylation of proteins could also be involved in the cell cycle dependent dynamics of cortical cytoskeletal structures other than microtubules.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080107
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    Bending patterns of Chlamydomonas flagella: IV. Mutants with defects in inner and outer dynein arms indicate differences in dynein arm function (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 68-75 
    Details
    ISSN: 0886-1544
    Keywords: dynein ; flagella ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mutants with outer dynein arm defects or deficiencies all show a major reduction in beat frequency to about half the normal value; some of these mutants show an additional decrease in sliding velocity associated with reduced shear amplitude and an additional reduction in beat frequency, as well as other more minor modifications of the normal forward mode bending pattern. New mutants (ida98, pf30), which appear to be deficient in a subset of inner dynein arms show a reduction in sliding velocity that is primarily associated with a reduction in shear amplitude, with only a small reduction in beat frequency. These differences in motility phenotype between inner and outer dynein arm mutants suggest that inner and outer dynein arms may have distinct functions. The relatively large decrease in sliding velocity associated with partial loss of inner arms is consistent with earlier observations on pf23, a nonmotile mutant lacking inner arms, suggesting that inner arms may have an essential function in motility. The ability to generate reverse mode bending patterns is retained in some inner or outer dynein arm mutants, but appears to be decreased in those mutants which show reduced shear amplitude for the forward mode bending pattern.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080110
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    Motile mechanism of blue damselfish (Chrysiptera cyanea) iridophores (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 85-90 
    Details
    ISSN: 0886-1544
    Keywords: blue damselfish ; motile iridophore ; microtubule ; colchicine ; EHNA ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Iridophores of the blue damselfish, Chrysiptera cyanea, responded to the sympathetic substance, norepinephrine by a shift towards longer wavelengths of the spectral peak of the light reflected by stacks of light-reflecting platelets (“coloring response”). All antimitotic reagents tested, i.e., colchicine, vinblastine, and podophyllotoxin, inhibited the response reversibly, while an actin inhibitor, cytochalasin B, did not. Erythro-9-[3-(2-hydroxynonyl)]adenine (EHNA), a dynein ATPase inhibitor, also blocked the iridophore response effectively. These results indicate that the tubulin-dynein system may be involved in the motility of iridophores, which is regarded as the simultaneous alteration of the distance between adjacent reflecting platelets within the cells.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080112
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    Amebae of Dictyostelium discoideum respond to an increasing temporal gradient of the chemoattractant cAMP with a reduced frequency of turning: Evidence for a temporal mechanism in ameboid chemotaxis (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 7-17 
    Details
    ISSN: 0886-1544
    Keywords: cell motility ; sensory transduction ; slime mold ; pseudopod formation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In an aggregation territory of Dictyostelium discoideum, outwardly moving, nondissipating waves of the chemoattractant cAMP sweep across each ameba. At the front of each wave, an ameba experiences an increasing temporal and a positive spatial gradient of cAMP. At the back of a wave, an ameba experiences a decreasing temporal and a negative spatial gradient of cAMP. Employing a perfusion chamber, we have mimicked the temporal dynamics of these waves in the absence of a spatial gradient and demonstrated that the frequency of lateral pseudopod formation and the frequency of turning are dramatically affected by the direction and dynamics of the temporal gradient. In addition, since an ameba will move in a directed fashion up a shallow, nonpulsatile gradient of cAMP, we also mimicked the increasing temporal gradient generated by an ameba moving up a shallow spatial gradient. The frequency of lateral pseudopod formation and the frequency of turning were depressed. Together, these results demonstrate that amebae can assess the direction of a temporal gradient of chemoattractant in the absence of a spatial gradient and alter both the frequency of pseudopod extension and turning, accordingly. Although these results do not rule out the involvement of a spatial mechanism in assessing a spatial gradient, they strongly suggest that the temporal dynamics of a cAMP wave or the temporal gradient generated by an ameba moving through a spatial gradient may play a major role in chemotaxis.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080103
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    Platelet intermediate filaments: Detection of a vimentinlike protein in human and bovine platelets (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 61-67 
    Details
    ISSN: 0886-1544
    Keywords: platelets ; cytoskeleton ; vimentin ; microtubules ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human and bovine platelets contain a 58,000-dalton vimentinlike protein that cross-reacts with antivimentin antibody. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blots indicate that this protein is present in whole platelet lysates and triton insoluble cytoskeletons. Transmission electron microscopy of platelets reveals an isotropic network of individual intermediate filaments distributed throughout the platelets. High salt, triton extracted, glutaraldehyde and tannic acid fixed platelets reveal 10-nm filaments that can be seen to form a peripheral ring, as well as an isotropic network in the body of the cells. Indirect immunofluorescence of resting and spread platelets demonstrates a circumferential staining pattern close to the cell membrane, with additional fibrillar staining throughout the platelets. Our data suggest that the 58,000-dalton vimentinlike protein may be associated with the microtuble coil and the plasma membrane, and may thus help to maintain the resting platelet's discoid shape.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080109
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    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080201
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    Topographical relationship between the axonemal arrangement and the bend direction in starfish sperm flagella (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 76-84 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; starfish spermatozoon ; proximal centriole ; bend direction ; bend asymmetry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Since starfish spermatozoa have spherical heads, it is not easy to determine the topographical relationship of the axoneme to the directions of the flagellar bends, the principal, and the reverse bends as defined by Gibbons and Gibbons [J. Cell. Biol. 1972, 63:970-985]. The demembranated spermatozoa are known to take the quiescent “cane” shape with a sharp principal bend at the proximal region of the flagellum in the presence of high concentration of Ca2+. When such spermatozoa were placed on a grid for electron microscopy, fixed with osmic acid vapor, washed with distilled water, and negatively stained with urany1 acetate, the head of the spermatozoon was disrupted and dispersed disclosing the proximal centriole at at the proximal end of the flagellum. The proximal centriole was always found on the concave side of the “cane” -shaped flagella. Electron microscopy of the serial thin sections of intact and demembranated spermatozoa revealed that the doublet microtobules numbers 5 and 6 were contained in the convex edge of the principal bend.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080111
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    Vimentin dynamics during the mitogenic stimulation of mouse splenic lymphocytes (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 227-237 
    Details
    ISSN: 0886-1544
    Keywords: Vimentin ; tubulin ; lymphocytes ; stimulation ; mitosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used double immunofluorescence and electron microscopy to examine the distribution of tubulin and vimentin during the stimulation of mouse splenic lymphocytes by the mitogen concanavalin A. In unstimulated cells, vimentin forms a filamentous network partially coincident with the radial pattern of microtubules. In stimulated cells, the numbers of microtubules assembled from the centrosome. When these cells enter mitosis, vimentin is arranged into a filamentous cage enclosing the mitotic apparatus. During cytokinesis, the polar centrosomes are observed at a position adjacent to the midbody and vimentin is detected as an aggregate, similar to that seen prior to mitosis, close to the centrosome in each daughter cell. Using several agents, such as colchicine, colcemid, nocodazole, and taxol, which affect microtubule assembly, we have observed that the vimentin system, although closely related spatially to the microtubule complex in lymphocytes, can still reorganize independently as these cells progress through in the cell cycle. Throughout mitogenic stimulation in the continued presence of taxol, microtubules are reorganized into a few thick bundles while the vimentin system undergoes a sequence of rearragements similar to those observed during normal stimulation. These data suggest that vimentin dynamics may be important in the progression of lymphocytes through the cell cycle in response to mitogen.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080304
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    High time-resolution analysis of transient bending patterns during ciliary responses following electric stimulation in sea urchin embryos (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 198-208 
    Details
    ISSN: 0886-1544
    Keywords: high-speed microcinematography ; Hemicentrotus ; primitive response ; ciliary reversal ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transient ciliary movement during responses to electric stimulation of embryos of the sea urchin, Hemicentrotus pulcherrimus, was analyzed in terms of angular direction with a time resolution of approximately 2 ms with high-speed microcinematography. In the primitive response, which can be induced only in the early stages of development of the embryo, bending transients always started with a short pause in the middle of the effective stroke, irrespective of beat position on stimulation. In the reversal response, induced only in the late stages of development, bending transients occurred with a delay as short as some 10 ms from stimulation, and with a transient sharp deviation from the normal beat before the cilium took the position of the beginning of the recovery stroke of the reversed beat. The delay was significantly shorter at the base than at the tip, suggesting that some form of signal travels along the cilium; the speed was ten times higher than that of propagating bends in the normal beat. These facts indicate that the sensitivity to internal changes resulting from stimulation of the axoneme may vary with development, ciliary beat positions, and regions along the cilium.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970070303
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  • 74
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    Regulation of activation state and flagellar wave form in epididymal rat sperm: Evidence for the involvement of both CA2+ and cAMP (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 324-332 
    Details
    ISSN: 0886-1544
    Keywords: sperm motility ; procaine ; calcium ; cAMP ; flagellum ; epididymis ; TMB-8 ; hyperactivation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rat sperm from the cauda epididymis exhibit increased motility, longevity, and a distinct circular pattern of flagellar curvature in response to 5 mM procaine-HCI or 0.1 mM 8-(N, N-diethylamino)-octyl-3,4,5-trimethoxybenzoate (TMB-8), reagents that are thought to play a role in the immobilization of free cellular calcium. Triton X-100-extracted sperm models will exhibit the same pattern of motility and curvature as procaine- or TMB-8-activated cells, but only when calcium is removed by a strong chelating agent, and in the pesence of cAMP (3 μM). Demembranated sperm models produced from epididymal rat sperm are quiescent unless cAMP is added. In these sperm models, the presence or absence of free calcium mediates a transition in flagellar curvature. The increased activity of the procaine-treated intact cells was not accompained by a change in cellular ATP content, nor was ATP availability the limiting factor in the quiescent sperm. Therefore, the increased motility produced by procaine is probably mediated by a fall in free intracellular Ca2+ accompained by a rise in cAMP. Our finding that calcium controls the curvature of sperm flagella may explain altered patterns of flagellar beating, such as the hyperactivated motility that sperm exhibit in the female reproductive tract.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080405
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    Structure and mass analysis of 12S and 19S dynein obtained from bull sperm flagella (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 368-374 
    Details
    ISSN: 0886-1544
    Keywords: STEM ; polypeptide composition ; ciliary motility ; dynein molecule ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Brookhaven scanning transmission electron microscpe (STEM) was used to elucidate the structures and masses of 12S and 19S dynein extracted from bull sperm flagella. The 12S particle was a single globular particle with an average mass of 311 ± 10 kdaltons. The 19S dynein particles consisted of two globular heads joined to a common base. The average mass of the 19S particle was 1.6 ± 0.04 × 106 daltons. Thus, with the exception of the larger mass, the bull sperm 19S dynein molecule resembles the two-headed 21S dynein obtained from sea urchin sperm flagella and the 18S dynein obtained from Chlamydomonas with the possibility of a third head giving rise to the 12S particle. The structure, mass and polypeptide composition of bull sperm flagella dynein is compared with outer arm dyneins previously obtained from Chlamydomonas, Tetrahymena, and sea urchin sperm flagella.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080409
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  • 76
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    Flagellar movement of intact and demembranated, reactivated ram spermatozoa (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 375-391 
    Details
    ISSN: 0886-1544
    Keywords: axoneme ; cilia ; flagella ; reactivation ; ram sperm ; high speed video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flagellar movement of intact ejaculated ram sperm, and of demembranated models reactivated with ATP, has been studied using high-speed, high-resolution video microscopy.Intact sperm attached to the coverslip by their heads had an average beat frequency of 20.9 Hz and an average wave amplitude of 20.2 μm. There was little difference in the beat frequency or waveform of these sperm and sperm swimming freely near the coverslip or captured by their heads with a micropipette and held far from the coverslip, inducationg that the flagellar waveform of ram sperm is relatively resistant to distorition as a result of immobilization of the head or proximity to a surface. The beat envelope was nearly planar as determined by observations of free-swimming sperm and sperm captured by their head and oriented so they were beating either parallel or perpendicular to the plane of focus.The effect of various conditions for demembranation and reactivation of the sperm were examined. Treatment of sperm with 0.2 % Triton X-100 removed most of their plasma membrane. Under optimal conditions, nearly 100 % of the demembranted sperm reactivated at MgATP2- concentrations ranging from ∼4 μM to ∼20 mM. From ∼ 1 mM to ∼ 10 mM MgATP2-, their beat pattern closely resembled that of intact sperm; beat frequency depended on MgATP2- concentration. Percent motility was maximal between pH 7.5 and 8.0 and decreased sharply below pH 7.0 and avove pH 8.5. The addition of 50 μM cAMP to the reactivation medium had no effect on percent motility or the beat pattern and did not accelerate the initiation of movement.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080410
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    Announcement optical approaches to the dynamics of cellular motility (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 404-405 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070412
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  • 78
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    Subcellular compartmentalization of phosphorylated neurofilament polypeptides in neurons (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 393-403 
    Details
    ISSN: 0886-1544
    Keywords: immunocytochemistry ; phosphorylation ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Immunocytochemistry and polyacrylamide gel electrophoresis have been used to study the distribution of phosphorylated forms of neurofilament antigens in rat brain. Immunostaining of tissue with an antisera produced against phosphatasesensitive domains of the 200-kilodalton (kd) neurofilament polypeptide showed that phosphorylated forms of this polypeptide were present in virtually all axons and certain somata and dendrites of neurons in different brain regions. Immunoblots of whole brain homogenate or a neurofilament preparation from rat revealed that the affinity-purified anti-200-kd sera used to immunostain tissue labeled the neurofilament-associated 200-kd band in a phosphatase-sensitive manner. Fine structural analysis of this immunoreactivity in tissue showed that whenever the labeled organelle could be identified, it was a microtubule. In contrast, immunoblot analysis of twice-cycled microtubules from porcine brain revealed that microtubules in vitro did not possess the 200-kd antigen that was observed in situ. The results suggest that our antibody recognizes a phosphorylated domain on the neurofilament involved in cross-linking neurofilaments and microtubules, and that in vivo, phosphorylated epitopes of the 200-kd neurofilament polypeptide are capable of associating with microtubules.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970070411
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  • 79
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    Intracellular acidification, guanine-nucleotide binding proteins, and cytoskeletal actin (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 1-6 
    Details
    ISSN: 0886-1544
    Keywords: actin ; G-protein ; pH ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The addition of propionic acid to rabbit neutrophils causes cell acidification and increases the amount of actin associated with the cytoskeleton. Both responses are rapid, and while the cell acidification is somewhat long-lasting, the increase in cytoskeletal actin is transient. It reaches a maximum value within 15 seconds and then return to the basal level. Unlike fMet-Leu-Phe, however, propionic acid does not cause a rise in the intracellular concentration of free calcium. Pretreatment of the cells with pertusis toxin inhibits the propionic acid-produced increase in cytoskeletal actin but not the decrease in intracellular pH. However, the rate of return to the base line of the cell acidification produced by propionic acid is diminished in cells pretreated with pertussis toxin. On the other hand, both the decrease in intracellular pH and the increase in cytoskeletal actin produced by fMet-Leu-Phe are inhibited by pertussis toxin treatment. The results presented here suggest two important points. First, while cell acidification may trigger directly or indirectly the association of actin with the cytoskeleton, it is certainly not sufficient. Second, a functional guanine-nucleotide regulatory protein is required for stimulated cytoskeletal actin. One or more components of the G-protein and/or their effects on phosphoinositide hydrolysis may increase the number of actin monomers and the availability of preexisting actin filaments to these monomers.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080102
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  • 80
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    Platelet-derived growth factor-induced alterations in vinculin distribution in porcine vascular smooth muscle cells (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 91-105 
    Details
    ISSN: 0886-1544
    Keywords: vinculin ; PDGF ; cell growth ; vascular smooth muscle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Exposure of porcine vascular smooth muscle cells to platelet-derived growth factor (PDGF; 18-180 ng/ml) but not epidermal growth factor (EGF; 30ng/ml), somatomedin C (SmC; 30 ng/ml), or insulin (10 μM), results in a rapid, reversible, time- and concentration-dependent disapperance of vinculin staining in adhesion plaques; actin-containing stress fibers also become disrupted following exposure of cells to PDGF. Disapperance of vinculin staining from adhesion plaques is also caused by 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 200-400 nM), though the time course of the disapperance of vinculin staining under these conditions takes longer than in cells exposed to PDGF. The PDGF-induced removal of vinculin from adhesion plaques was inhibited in a concentration-dependent fashion by 8-(N, N-diethylamin) octy1-3,4,5-trimethoxybenzoate (TMA-8; 0.25-4 μM) and leupepetin (2-300 μM), and by n-α-rosyl-L-lysine chloromethylketone (TLCK; 100 μM) and trifluoperazine (TFP; 2.5 μM). Addition of PDGF to vascular smooth muscle cells caused a rapid, tranient increase in cytosolic free calcium, from a basal resting level of 146 ± 6.9 nM (SEM, n=62) to 414 ± 34 nM (SEM, n=22) as determined using the calcium-sensitive indicator Fura-2 and Digitized Video Microscopy. This increase in cellular calcium preceded the disappearance of vinculin from adhesion plaques and was partially blocked by pretreatment of cells with TMB-8 but not leupeption. This rise in cytosolic free calcium was found to occur in ∼ 80% of the sample population and dispalyed both spatial and temporal subcellular heterogeneity. Exposure of cells to TPA (100 nM) did not result in a change in cytosolic free calcium. Both PDGF (20 ng/ml) and TPA (100 nM) caused cytosolic alkalinization which occurred after PDGF-induced disruption of vinculin from adhesion plaques, as determined using the pH-sensitive indicator BCECF and Digitized Video Microscopy. PDGF stimulated DNA synthesis and vinculin disruption in a similar dose-dependent fashion. Both could be inhibited by leupeptin or TMB-8. These results suggest that 1) exposure of vascular smooth muscle cells to PDGF is associated with the disruption of vinculin from adhesion plaques, 2) PDGF-induced vinculin disruption is regulated by an increase in cytosolic calcium (but not cytosolic alkalinization), and involves proteolysis; 3) activation of protein kinase C also causes vinculin removal from adhesion plaques but by a calcium-independent mechanism, and 4) the cellular response to PDGF-stimulated increases in cytosolic free calcium is heterogeneous. Our data also suggest that cytosolic vinculin distribution is a sensitive indicator of the response of vascular smooth muslce cells to PDGF.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080202
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  • 81
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    Stress fiber reformation after ATP depletion (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 118-129 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; actin ; alpha-actin ; vinuclin ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Flurescently labeled heavy mermoyosin, alpha-actinin, and vinculin were used to localize actin, and vinculin, respectively, in permeabilized and living cells during the process of stress fiber reassembly, which occurred when cells were removed from ATP-depleting medium (20 mM sodium azide and 10 mM 2-deoxyglucose). In 80% of the cells recovering from ATP depletion, small, scattered plaques containing actin, alpha-actinin, and vinculin were replaced by long, thin, periodic fibers within 5 minutes of removal of the inhibitors. These nascent stress fibers grew broader as recovery progressed, until they attained the thickness of stress fibers in control cells. In the other 20% of the cells, the scattered plaques aggregated within 5 minutes of reversal, and almost all the actin, alpha-actinin, and vinculin in the cell became localized in one perinuclear aggregate, with a diameter of approximaterly 15-25 μm. As recovery progressed, all aggregates resembled rings, with diameters that increased at about 0.5 μm/minute and grew to as large as 70 μm in some giant cells. As the size of the rings increased, fibers radiated outward from them and sometimes spanned the diamater of te rings. The shape of the cells did not change during this time. By 1 hour after reversal, the rings were no longer present and all cells had networks of stress fibers. Indirect immunofluorescence techniques used to localize tubulin and vimentin indicated that microtubules and intermediate filaments were not constituents of the rings, and the rings were not closely apposed to the substrate, judging from reflection contrast optics. The rapid rearrangement of attachment plaques into a perinuclear aggregate that spreads radially in the cytoplasm occurs at the same speed as fibroblast and chromosomal movement, but is unlike other types of intracytoplasmic motility.
    Additional Material: 24 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080204
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  • 82
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    Subcortical rotation in Xenopus eggs: A preliminary study of its mechanochemical basis (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 143-154 
    Details
    ISSN: 0886-1544
    Keywords: amphibian egg ; Nile blue stain ; microtubules ; subcortial rotation ; cytoplasmic movement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The amphibian egg undergoes a 30° rotation of its subcortical contents relative to its surface during the first cell cycle, a displacement of 350 μm in 50 min. This is directly visualized by following the movement of an array of Nile blue (a subcortical stain) spots applied to the egg periphery (Vincent, Oster, and Gerhart: Dev Bio 113:484-500, '86). We have investigated the mechanochemical basis of this unusual cell motility. Subcortical rotation depends on microtubule integrity during its entire course and is insensitive to inhibitors of microfilament assembly. It does not depend on newly synthesized proteins for its operation or timing, and it does not involve calcium-dependent processes. Finally, we show that vegetal fragments of the egg can complete rotation on their own, indicating that mechanochemical components can operate locally in this hemisphere.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080206
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  • 83
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    Cell type-specific association between two types of spectrin and two types of intermediate filaments (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 165-173 
    Details
    ISSN: 0886-1544
    Keywords: erythrocytes ; brain ; vimentin ; neurofilaments ; desmin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have demonstrated a differential association between two types of spectrin, from erythrocytes and brain, with two types of intermediate filaments, vimentin filaments and neurofilaments. Electron microscopy showed that erythrocyte spectrin promoted the binding of vimentin filaments to red cell inside-out vesicles via lateral associations with the filaments. In vitro binding studies showed that the association of spectrin with vimentin filaments was apparently saturable, increased with temperature, and could be prevented by heat denaturation of the spectrin. Comparisons were made between erythrocyte and brain spectrin binding to both vimentin filaments and neurofilaments. We found that vimentin filaments bound more erythrocyte spectrin than brain spectrin, while neurofilaments bound more brain spectrin than erythrocyte spectrin. Our results show that both erythroid and nonerythroid spectrins are capable of binding to intermediate filaments and that such association may be characterized by differential affinities of the various types of spectrin with the several classes of intermediate filaments present in cells. Our results also suggest a role for both erythroid and nonerythroid spectrins in mediating the association of intermediate filaments with plasma membranes or other cytoskeletal elements.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080208
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  • 84
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    Binding of mammalian brain microtubule-associated proteins (MAPs) to insect ovarian microtubules (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 174-181 
    Details
    ISSN: 0886-1544
    Keywords: evolutionary conservation ; side-arms ; binding sites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this study we have applied microtubule-associated proteins (MAPs) from mammalian brain to both native and reassembled insect ovarian microtubules. Such microtubules, which are normally smooth walled, become decorated with projections similar to those observed when mammalian brain MAPs are added back to assembling or assembled mammalian brain microtubules. The mammalian MAPs were also detected as components of insect microtubules when analyzed by polyacrylamide gel electrophoresis. Our observations suggest that mammalian brain MAPs have common binding sites on microtubules from two widely different sources and indicate the degree of evolutionary conservation of such sites.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080209
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  • 85
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    Unity in diversity (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 190-191 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080211
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  • 86
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    Analysis of the flagellar bending waves of ejaculated ram sperm (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 261-273 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; flagella ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The variability of flagellar movement, illustrated by the highly heterogenous nature of the ejaculated sperm population of the ram, was analyzed by the use of a stroboscopic technique and an adapted microphotographic 24 × 36 camera system. The multiple-moving-exposures (MME) records give very distinct successive sequences of the flagellar beats and are particularly suitable for the analysis of bend development and propagation along the tail. With this technique, the parameters of the flagellar bending waves of ejaculated ram sperm have been determined. Most of the sperm have planar flagellar beatings; few are rolling under the conditions of observation. The trajectories of the gametes are mostly linear; nevertheless, some have circular paths. The analysis of bending has been focused on two examples for which the difference in the progressiveness ratio was maximum. The circular pathways for ram spermatozoa are linked to an asymmetry between principal and reverse bend probably induced by differences in wave propagation evidenced along the flagellum. A typical sperm flagellar movement may be related either to the conditions of the observations or to some differences in the maturation process of the sperm.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080307
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  • 87
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    Dynamics of behaviour during neuronal morphogenesis in culture (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 250-260 
    Details
    ISSN: 0886-1544
    Keywords: time lapse ; neuronal differentiation ; cytoskeleton ; growth cone ; PC12 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report a developmental sequence in the type and frequency of behaviours of neurons differentiating in vitro. We characterised these changes with extensive analysis of time-lapse sequence from both the continuing cell line phenochromocytoma PC12 and primary mixed cell culture of cat and mouse central nervous system. PC12 cells activated by nerve growth factor (NGF) differentiate in a uniform and synchronous manner. This allowed the first quantification of changes in different neuron behaviours during morphogenesis.Shortly after NGF activation, PC12 cells are highly labile in morphology and exhibit a large variety of morphological behaviours. During the first week of differentiation, the frequency of these behaviours declines, and gross morphology becomes more stable. The frequency of neurite initiation after 1 week in NGF is one-seventh what it was after 2 days in NGF. Over the same period, neurite retraction declines to one-third, and somal migration ceases altogether. Growthcone activity does not decline during development. These behaviour changes correlate with published data on the differentiation of the neurite cytoskeleton.A qualitatively similar ontogeny was noted in the differentiation of CNS neurons in mixed cell culture. Major differnces occur in the relative timing of changes in behaviours. Mature, stable morphology is not detected in these cultures until 7 weeks in vitro.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080306
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  • 88
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    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080401
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  • 89
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    Microinjected carboxylated beads move predominantly poleward in sea urchin eggs (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 293-301 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; particle motility ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Observations on living mitoic cells have suggested that material in the spindle moves poleward during mitosis. In order to investigate this movement, sea urchin eggs have been microinjected with 0.25-μm diameter carboxylated fluorescent beads. When fluorescent beads were injected into unfertilized Lytechinus variegatus eggs, no motility was detected. When injected into mitotic cells, beads moved to the spindle poles. Individual beads moved rapidly, in a saltory fashion, and followed generally linear paths. Beads appeared to move along astral fibers, were generally excluded from thespindle proper, and accumulated at the spindle poles. Some dispersion of the beads away from the pole was observed as cells completed mitosis, but the majority of beads retained a polar location. After depolymerization of spindle microtubules with nocodazole, some dispersion of beads into the cytoplasm was also observed. Beads moved along taxol-induced astral microtubules and accumulated at astral centers. These observations reveal that negatively chargedbeads accumulate rapidly at mitotic centers, moving toward the minus end of the microtubules. Neither the bidirectional motility of similar beads in interphase cells nor the plus-end-directed bead motility seen in axons was observed in these mitotic cells.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080402
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  • 90
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    In vitro effects of benzodiazepines on ciliogenesis in the quail oviduct (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 333-344 
    Details
    ISSN: 0886-1544
    Keywords: basal body migration ; cilia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Immature oviduct implants from quails stimulated by estrogen to induce ciliogenesis were submitted to the in vitro action of benzodiazepines in organotypic culture. Diazepam and medazepam were added to the culture medium for 24 or 48 hours and tissues were examined by transmission and scanning electron microscopy for alterations in ciliary differentiation.Ciliogenesis was inhibited by both diazepam and medazepam, which affected mainly the migration of the basal bodies. Assembly of basal bodies was achieved normally in the cytoplasm, but their separation from generative complexes and migration toward the apical membrane were prevented. They remained in clusters around a deuteosome or eventually anchored to the close lateral plasma membrane.Furthermore, the drugs affected mature beating cilia, which then appeared lying tangentially to the cell surface. Relation between basal bodies and cortical cytoskeleton seemed to be altered by the drugs, which implies that the bearing of cilia and probably the ciliary beating movement were modified. Mocrovillus development was also altered by the action of these drugs.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080406
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  • 91
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    Identification and characterizaton of a protein associated with the stembody using autoimmune sera from patients with systemic sclerosis (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 360-367 
    Details
    ISSN: 0886-1544
    Keywords: spindle ; autoantibody ; CREST ; scleroderma ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An autoantibody that binds an antigen localized to the stembody of dividing cells has been identified in a patient with systemic sclerosis. Initially, this antigen is associated with the surface of the metaphase chromosomes. At the onset of anaphase the antigen becomes preferentially associated with the forming stembodies. This association is maintained as furrowing progresses during telophase and continues after the intercellular bridge is released from the daughter cells during G-1. Immunoblots indicate that the epitope detected by immunoflurorescence is present on a protein with an apparent molecular weight of 38 kD.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970080408
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  • 92
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    Distribution of myosin and relationship to actin organization in cortical and subcortical areas of antibody-labelled, quick-frozen, deep-etched fibroblast cytoskeletons (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 368-380 
    Details
    ISSN: 0886-1544
    Keywords: cell motility ; rapid freezing ; cytoskeletal architecture ; immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this study I describe the ultrastructural distribution of myosin in cortical and subcortical areas of antibody-labelled, quick-frozen fibroblasts. In many cells myosin was present in small variably spaced and sized (0.23-0.39 μm long), nonaligned patches, while in other cells much larger periodically spaced patches of more uniform length (0.27 μm) were found. In all regions of the cytoskeleton myosin was found, primarily on linear bundles of actin filaments running parallel to the cell's long axis.Myosin was absent from single actin filaments, actin Filaments perpendicular to actin bundles aligned with the cell's long axis, and actin filaments, such as geodome vertices and parts of the cortex, which had a complex interwoven appearance. These data indicate that in motile non-muscle cells myosin exerts force only in a unidirectional manner. Recognisable myosin filaments were never observed even in cells incubated either in N-ethylmaleimide or sodium azide. The presence of myosin in, and almost to the very edge of, the cortex suggests that the cellular control of actomyosin based movement is direct and over short-range distances. Large numbers of small cross-linking filaments were found in association with cortical and subcortical actin. Their relationship to myosin and overall actin geometry is discussed.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970070409
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  • 93
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    Cytochalasin B-induced redistribution of cytokeratin filaments in PtK1 cells (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 347-360 
    Details
    ISSN: 0886-1544
    Keywords: cytochalasin ; actin ; microtubules ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Indirect immunofluorescence demonstrated a dramatic reorganization of cytokeratin filaments produced by cytochalasin B (CB) treatment of PtK1 cells. Much of the normal cytokeratin network became arranged into a latticework consisting of bundles of cytokeratin filaments that radiated from, and interconnected, distinct foci, Electron microscopy showed foci to be dense granular regions through which bundles of cytokeratin filaments looped. Composition of the foci included actin, myosin, and alpha-actinin, as shown by labeling with rhodamine phalloidin or specific antisera. Simultaneous treatment with CB and colchicine was not required for lattice formation, but did produce more extensive development than did CB alone. In cells treated only with CB, the microtubule network remained intact, even in regions of extensive lattice formation. These results contrast sharply with those of Knapp et al (J. Cell Biol. 97:1788 [1983b]), who found lattice formation dependent upon simultaneous CB and colchicine treatment. Time-course and dose-response studies of CB treatment showed lattice formation to follow disruption of stress fibers and the concentration of actin into distinct patches that marked the location of lattice foci. Overall results suggest a structural association between microfilaments and cytokeratin filaments that produces the lattice pattern upon CB-induced disruption of stress fibers. Lattice formation was not limited to a specific cell-cycle stage, since G1, G2, and M cells displayed the lattice. Treatment of cells with dihydro-CB and experiments with enucleated cells showed that lattice formation was dependent upon neither the inhibition of sugar transport nor the nuclear extrusion effects of CB.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070407
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  • 94
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    Monoclonal antibodies against plant proteins recognise animal intermediate filaments (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 312-323 
    Details
    ISSN: 0886-1544
    Keywords: plant cytoskeleton ; Chlamydomonas ; anti-IFA ; onion root tip cells ; immunoflurescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four monoclonal antibodies were raised against polypetides present in a highsalt detergent-insoluble fraction from cells of Chlamydomonas reinhardtii. Indirect immunofluorescence microscopy of fibroblasts and epithelial cells grown in culture using these plant antibodies revealed staining arrays identical to those obtained with well characterised antibodies to animal intermediate filaments. Immunoflurescence microscopy of Chlamydomonas with these monoclonal antibodies and a monoclonal antibody that recognises all animal intermediate filaments (anti-IFA) gave a diffuse, patchy cytoplasmic staining pattern. Both the plant antibodies and anti-IFA stained interphase onion root tip cells in a diffuse perinuclear pattern. In metaphase through to telophase, the labelling patterns colocalised with those of microtubules. Labelling of the phragmoplast was also detected but not staining of the preprophase band. On Western blots of various animal cell lines and tissues, all the antibodies labelled known intermediate filament proteins. On Western blots of whole Chlamydomonas proteins, all the antiboides labelled a broad band in the 57,000 Mr range, and three antibodies labelled bands around 66,000 and 140,000 Mr but with varibale intensites. On Western blots of whole onion root tip proteins, all the antibodies labelled 50,0000 Mr (two to three bands) polypetides and a diffuse and around 60,000 Mr and three of the antibodies also labelled several polypeptides in the 90,000-200,000 Mr range. The consistent labelling of these different bands by several different monoclonal antibodies recognising animal intermediate filaments makes these polypetides putative plant intermediate filament proteins.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080404
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  • 95
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    Contractility of the spasmoneme in glycerinated Vorticella stalk induced by various divalent metal and lanthanide ions (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 39-45 
    Details
    ISSN: 0886-1544
    Keywords: divalent metal ions ; lanthanide ions ; calcium contraction ; spasmoneme ; Vorticella ; stalk ; contractile regulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The glycerinated stalks of the peritrich ciliate, Vorticella, can contract helically and reversibly on the addition of not only Ca2+ but also other divalent or trivalent cations having ionic radii not far from 1 Å. In order to investigate the stalk contraction quantitatively in the absence of Ca2+-chelators, we developed a method to eliminate contaminating Ca2+ and other metal ions in KC1 and pHbuffer solutions by using a Ca2+-and heavy metal ion-specific ion exchange resin (Eporas MX-2) Thus, it was possible to measure the relationship between the fractional stalk length of Vorticella and the free concentration of alkaline earth metal, transition metal, and lanthanide ions in the 0.1 M KC1 and buffer (pH 6.8) solutions. Among these ions, Ca2+, Nd3+, and Eu3+ (having ionic radii of about 1 Å) had the highest affinity for the contractile element in the spasmoneme. As the concentration of lanthanide ions (except Nd3+ and Eu3+) is increased, the Vorticella stalk contracts abruptly at a threshold level; this means that the Hill's parameter is very high, probably more than 6. The results of these experiments and of the co-mixtures of Ca2+ and Tb3+ suggest that a contractile element in the spasmoneme contains both contractile Ca2+-binding and regulatory Ca2+-binding sites.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070106
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  • 96
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    Spindle function in the green alga Mougeotia: Absence of anaphase A correlates with postmitotic nuclear migration (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 68-77 
    Details
    ISSN: 0886-1544
    Keywords: microtubule ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the filamentous green alga Mougeotia, each daughter nucleus formed by mitosis is then rapidly moved along the recently divided daughter cell to the central cleavage developing in the chloroplast. This movement is brought about by a cone-shaped array of microtubules (MTs) that ensheath the daughter nucleus and are focused upon a small region, presumably a microtubule-organising center (MTOC). Movement is completed when the MTOC locates and then resides in the chloroplast cleavage, drawing the nucleus into this position.The mitotic spindle is open with initially broad, ill-defined poles. Anaphase A contributes minimally, if at all, to chromosome separation since the half spindles remain about the same length during anaphase and telophase. Thus, anaphase is accommodated and probably achieved by spindle elongation; the interzonal MTs also generate a rudimentary phragmoplast at the ingrowing cleavage furrow. The persistent polar MTs become directly transformed into the cone-shaped array and initiate nuclear movement during early telophase. Various closely or distantly related green algae show this trait of persistent polar MTs. We conclude that this trait has allowed some species to evolve a motility system based directly on the capabilities of astral MTs, for generating the postmitotic nuclear movement essential for the restoration of the interphase cell organization.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070109
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  • 97
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    Isolation and characterization of sea urchin egg spectrin: Calcium modulation of the spectrin-actin interaction (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 304-314 
    Details
    ISSN: 0886-1544
    Keywords: spectrin-like ; actin-binding protein ; Ca++-regulated ; cytoskeleton ; eggs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sea urchin egg spectrin has been purified from a homogenate of unfertilized Strongylocentrotus purpuratus eggs using standard biochemical procedures. SDS-PAGE analysis of the molecule revealed a closely spaced, high molecular weight doublet at 237/234 kDa (present in an equimolar ratio). Rotary shadowed images of egg spectrin revealed a double-stranded, elongate, flexible rod-shaped contour, measuring 210 nm in length and ∼ 4-8 nm in width. Additionally, this molecule is shown to be immunologically related to avian erythroid spectrin, since it cross-reacts with antibodies prepared against the chicken erythrocyte α-spectrin/240 kDa subunit. The interaction of egg spectrin with actin was examined by sedimentation and falling-ball viscometry assays. The binding and cross linking properties of spectrin to actin demonstrate a unique Ca++-sensitive regulation at micromolar Ca++ concentrations. This observation provides new insight into the way Ca++ may regulate spectrin-actin interactions in vitro and further suggests possible structural and modulatory roles for egg spectrin in the developing sea urchin embryo.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070403
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  • 98
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    Cordycepin disrupts the microtubule networks and arrests nil 8 hamster fibroblasts at the onset of mitosis (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 337-346 
    Details
    ISSN: 0886-1544
    Keywords: cordycepin ; microtubules ; mitosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nucleoside analogue 3′-deoxyadenosine (cordycepin) arrests dividing cells at the onset of mitosis in prometaphase. The microtubules in the arrested prometaphase cells depolymerize to two small asters. A minimum of 80 μg/ml cordycepin or 20 μg/ml cordycepin in combination with 2 μg/ml of the deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl) adenosine (EHNA) lo inhibit its degradation is required to see these effects. Analysis of cell extracts by high-pressure liquid chromatography indicates that cordycepin enters the cells rapidly and is phosphorylated to 3′-dATP. The intracellular concentration rises almost linearly from 0.7 mM after 15 min to 7 mM by 210 min. Concomitantly the ATP concentration shows a rapid drop from the 4 mM present in controls. However, the direct reduction of ATP levels does not mimic the same rapid effects of cordycepin on the microtubules. In addition, similar effects are not produced by a variety of other adenosine analogues with alterations in the 2′ and 3′ ribose positions. Although other pharmacological reagents arrest cells at the onset of mitosis, cordycepin is unusual because of the collapse of the microtubule networks to two small asters that radiate from the microtubule-organizing center. 3′-dATP can replace the requirement for ATP or GTP in the vitro polymerization of microtubules from microtubule protein: however, at limiting concentrations of nucleotide it requires approximately two times the concentration of 3′-dATP as ATP to support an equivalent level of microtubule polymerization. This suggests that the effects of cordycepin in vivo may be the result of the depletion of cellular ATP pools and the altered ability of 3′dATP to substitute for ATP-dependent reactions. Current experiments are testing this hypothesis.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070406
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  • 99
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    Axonal tubulin and microtubules: Morphologic evidence for stable regions on axonal microtubules (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 155-164 
    Details
    ISSN: 0886-1544
    Keywords: cold stability ; cytoskeleton ; depolymerization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Biochemical studies indicate that axonal tubulin is composed of at least two distinct pools that differ in cold solubility and biochmical composition [Brady et al: J. Cell Biol. 99:1716-1724]. To determine the morphologic correlate of cold-insoluble tubulin, segemnts of rat optic nerves were exposed to a series of in vitro experimental conditions that affect microtubules (MTs), including cold, podophyllotoxin (PT), triflupromazine (TFP), and taxol, and then examined by electron microscopy. Longitudinal sections of control axons showed MTs oriented parallel to the long axis of the axons. Axond exposed to Cold, PT, and TFP showed short segments of MTs in association with cytoskeletal disarray. Morphometric studies were used to distinguish between a simple malorientation of MTs (undulation or zigzags in their course) and the loss of labile segments of MTs, leaving the stable portions behind. The lengths of MT segments were measured in longitudinal sections, and the numbers of MTs were determined in the cross sections. All MT segment-length histograms showed a unimodal distribution. Cold and PT produced a simple shift of the control histogram to the shorter length MTs. In cross sections the numbers of MTs in cold- and PT-exposed axons were significantly decreased, indicating that the presence of short segments of MTs. Taxol, an agent that promotes MT assembly, reversed the cold effect partially and resulted in increases in both MT segment lenght and number. These studies indicate that stable MT segments are portions of longer MTs containing both stable and labile regions. Furthermore, these findings are consistent with the hypothesis that cold-insoluble tubulin functions as a transportable MT-organizing complex in the axon.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080207
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  • 100
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    A critical role for the polarization of membrane recycling in cell motility (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 182-189 
    Details
    ISSN: 0886-1544
    Keywords: Golgi apparatus ; microtubule-organizing center ; G-glycoprotein ; cytochalasin D ; monensin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper is concerned with the proposition that the insertion of membrane mass into the leading edge of a motile cell plays a critical role in directed cell migration. We show by immunofluorescence, with cells transfected with a cloned cDNA encoding the G-protein of a temperature-sensitive mutant of vesicular stomatitis virus, that the first cell surface appearance of the G-protein is indeed at the leading edge of the motile cell. Two drugs capable of inhibiting directed cell migration, cytochalasin D and monensin, appear to function independently, the former by affecting the actin cytoskeleton without affecting the polarized insertion of membrane mass into the cell surface and the latter by abrogating membrane mass insertion without affecting the actin cytoskeleton.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080210
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