Binding of Tetrahymena dynein to axonemes of Marsilea vestita lacking the outer dynein arm

1985 ◽  
Vol 73 (1) ◽  
pp. 299-310
Author(s):  
J.S. Hyams
Keyword(s):  
Electron Microscopy ◽  
Polyacrylamide Gel Electrophoresis ◽  
Valuable Insight ◽  
Marsilea Vestita ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
And Function ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Axonemes from the heterosporous water fern Marsilea vestita were fixed in the presence of tannic acid and examined by thin-section electron microscopy. Transverse sections revealed the normal 9+2 configuration except for the absence of the outer of the two dynein arms. Both arms were normally preserved in parallel preparations of Chlamydomonas axonemes. Isolated dynein from the ciliated protozoon Tetrahymena bound to Marsilea axonemes at the site normally occupied by the outer arm. Dynein binding was partially reversed by ATP as judged by both electron microscopy and polyacrylamide gel electrophoresis. This system should provide a valuable insight into the biochemistry and function of the inner dynein arm and the relationship of the two arms to motility in more conventionally equipped axonemes.

scholarly journals Quick-Freeze, Deep-Etch Electron Microscopy Reveals the Characteristic Architecture of the Fission Yeast Spore

2020 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Yuhei O. Tahara ◽  
Makoto Miyata ◽  
Taro Nakamura
Keyword(s):  
Electron Microscopy ◽  
Cell Membrane ◽  
Fission Yeast ◽  
Dormant Cell ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Cell Surface Changes ◽  
Insight Into ◽  
Spore Cell ◽  
Surface Changes

The spore of the fission yeast Schizosaccharomyces pombe is a dormant cell that is resistant to a variety of environmental stresses. The S. pombe spore is coated by a proteinaceous surface layer, termed the Isp3 layer because it comprises mainly Isp3 protein. Although thin-section electron microscopy and scanning electron microscopy have revealed the fundamental structure of the spore, its architecture remains unclear. Here we visualized S. pombe spores by using a quick-freeze replica electron microscopy (QFDE-EM) at nanometer resolution, which revealed novel characteristic structures. QFDE-EM revealed that the Isp3 layer exists as an interwoven fibrillar layer. On the spore cell membrane, many deep invaginations, which are longer than those on the vegetative cell membrane, are aligned in parallel. We also observed that during spore germination, the cell surface changes from a smooth to a dendritic filamentous structure, the latter being characteristic of vegetative cells. These findings provide significant insight into not only the structural composition of the spore, but also the mechanism underlying the stress response of the cell.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

scholarly journals RELATION OF ADRENAL CORTICAL HORMONE TO LYMPHOID TISSUE AND LYMPHOCYTES

Blood ◽  
1948 ◽  
Vol 3 (7) ◽  
pp. 729-754 ◽  
Author(s):  
WILLIAM N. VALENTINE ◽  
CHARLES G. CRADDOCK ◽  
JOHN S. LAWRENCE
Keyword(s):  
Adrenal Cortex ◽  
Lymphoid Tissue ◽  
Hormonal Control ◽  
Tissue Structure ◽  
Lymphoid Tissues ◽  
Adrenal Cortical Hormone ◽  
Cortical System ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

Abstract The hormonal control through the hypophyseo-adrenal cortical system of lymphoid tissue structure and function is an important concept. We cannot at the present time regard that the concept is established fact. Final judgment must await additional work and the clarification of some of the inconsistencies which appear to exist. It seems reasonable that lymphoid tissue is one of the end organs of adrenal cortical hormone and that it may perhaps play a role in the response of the organism to stress. It seems quite clear that the sugar hormone of the adrenal cortex is capable of producing structural alterations in lymphoid tissue. Change in thoracic duct lymphocyte numbers as a result of augmentation in the amount of available adrenal cortical hormone is at present controversial. Experiments in this laboratory have failed to demonstrate it. The production of lymphopenia, at least in some species and possibly in man, by increasing available sugar hormone is supported by some evidence. The exact mechanism of production of lymphopenia is open to question, its relationship to changes in lymphoid tissue structure being one of inference. The converse situation—absolute lympocytosis resulting from deprivation of adrenal cortical hormone—is the subject of controversial reports. At best, it must be admitted that relatively slight alterations from the accepted normal range of lymphocyte values occur in the adrenal insufficient organism. Changes in plasma gamma globulins and antibody titers associated with changes in the amount of available cortical hormone are reported. It should be clarified whether such changes have necessarily resulted from lymphocyte dissolution or are related to other of the variegated actions of adrenal cortical hormone. The relationship of adrenal cortical hormone to lymphoid tissue and lymphocytes and the relationship of the latter to the response of the organism to stress must indeed be complex. It is reasonably well established that the life span of the lymphocyte is very short indeed1,58,22 and each lymphocyte presumably liberates its metabolically important contents within a few hours at the most. If stress continues for any period of time, as often it does, it is difficult to visualize the wisdom of interfering with the production of metabolically vital substances in order to secure the transient benefits of lymphoid tissue dissolution. It is also somewhat difficult to regard as proved that the various changes reported after hormone augmentation or deprivation necessarily represent the normal mechanism by which these factors are regulated and kept within physiologic limits. More investigations are required to answer such questions and to further elucidate the interrelationship of the adrenal cortex and lymphoid tissues.

scholarly journals DNA AND THE FINE STRUCTURE OF SYNAPTIC CHROMOSOMES IN THE DOMESTIC ROOSTER (GALLUS DOMESTICUS)

1964 ◽  
Vol 23 (1) ◽  
pp. 63-78 ◽  
Author(s):  
James R. Coleman ◽  
Montrose J. Moses
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Fine Structure ◽  
Electron Microscope ◽  
Meiotic Prophase ◽  
Gallus Domesticus ◽  
Feulgen Staining ◽  
Synaptinemal Complex ◽  
Relationship Of ◽  
The Relationship

The indium trichloride method of Watson and Aldridge (38) for staining nucleic acids for electron microscopy was employed to study the relationship of DNA to the structure of the synaptinemal complex in meiotic prophase chromosomes of the domestic rooster. The selectivity of the method was demonstrated in untreated and DNase-digested testis material by comparing the distribution of indium staining in the electron microscope to Feulgen staining and ultraviolet absorption in thicker sections seen with the light microscope. Following staining by indium, DNA was found mainly in the microfibril component of the synaptinemal complex. When DNA was known to have been removed from aldehyde-fixed material by digestion with DNase, indium stainability was also lost. However, staining of the digested material with non-selective heavy metal techniques demonstrated the presence of material other than DNA in the microfibrils and showed that little alteration in appearance of the chromosome resulted from DNA removal. The two dense lateral axial elements of the synaptinemal complex, but not the central one to any extent, also contained DNA, together with non-DNA material.

The impact of tinnitus characteristics and associated variables on tinnitus-related handicap

2015 ◽  
Vol 130 (1) ◽  
pp. 25-31 ◽  
Author(s):  
S Degeest ◽  
P Corthals ◽  
I Dhooge ◽  
H Keppler
Keyword(s):  
Additional Insight ◽  
Tinnitus Handicap Inventory ◽  
Hearing Status ◽  
Questionnaire Score ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship ◽  
Sample Case ◽  
Insight Into ◽  
Associated Variables

AbstractObjective:This study aimed to determine the characteristics of tinnitus and tinnitus-related variables and explore their possible relationship with tinnitus-related handicap.Methods:Eighty-one patients with chronic tinnitus were included. The study protocol measured hearing status, tinnitus pitch, loudness, maskability and loudness discomfort levels. All patients filled in the Tinnitus Sample Case History Questionnaire, the Hyperacusis Questionnaire and the Tinnitus Handicap Inventory. The relationship of each variable with the Tinnitus Handicap Inventory score was evaluated by univariate and multivariate analyses.Results:Five univariables were associated with the Tinnitus Handicap Inventory score: loudness discomfort level, subjective tinnitus loudness, tinnitus awareness, noise intolerance and Hyperacusis Questionnaire score. Multiple regression analysis showed that the Hyperacusis Questionnaire score and tinnitus awareness were independently associated with the Tinnitus Handicap Inventory score.Conclusion:Hyperacusis and tinnitus awareness were independently associated with the Tinnitus Handicap Inventory score. Questionnaires on tinnitus and hyperacusis are especially suited to providing additional insight into tinnitus-related handicap and are therefore useful for evaluating tinnitus patients.

scholarly journals TARGETED ADVERTISING IN THE BREAKFAST CEREAL INDUSTRY

2017 ◽  
Vol 49 (3) ◽  
pp. 382-399 ◽  
Author(s):  
JOSHUA BERNING ◽  
ADAM N. RABINOWITZ
Keyword(s):  
Product Differentiation ◽  
Food Product ◽  
Television Advertising ◽  
Breakfast Cereal ◽  
Data Set ◽  
Policy Makers ◽  
Relationship Of ◽  
Cereal Industry ◽  
The Relationship ◽  
Insight Into

AbstractWe examine the relationship of product characteristics of ready-to-eat breakfast cereal and targeted television advertising to specific consumer segments. We compile a unique data set that includes brand-packaging characteristics, including on-box games, nutrition information, and cobranding. We find that the relationship of television advertising and a cereal's brand-packaging characteristics varies by target audience. Our results provide insight into understanding how manufacturers strategically utilize branding, packaging, and television advertising. This can help industry and policy makers develop food product advertising policy. This analysis extends to other product markets where extensive product differentiation and promotion are present as well.

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