scholarly journals On Flagellar Structure in Certain Flagellates

1960 ◽  
Vol 7 (4) ◽  
pp. 697-716 ◽  
Author(s):  
I. R. Gibbons ◽  
A. V. Grimstone
Keyword(s):  
Basal Body ◽  
Basal Bodies ◽  
Complex Structures ◽  
The Third ◽  
Two Systems

This paper describes the structure of the flagella, basal bodies, and some of the associated fibre systems in three genera of complex flagellates, Trichonympha, Pseudotrichonympha, and Holomastigotoides. Three groups of longitudinal fibres occur in a flagellum: two central and nine outer fibres such as have been repeatedly described in other material, and an additional set of nine smaller secondary fibres not previously identified as such. Each central fibre shows a helical substructure; the pair of them are enveloped in a common sheath. Each outer fibre is a doublet with one subfibre bearing projections—called arms—that extend toward the adjacent outer fibre. The basal body is formed by a cylinder of nine triplet outer fibres. Two subfibres of each triplet continue into the flagellum and constitute the doublets. The third subfibre terminates at the transition of basal body to flagellum, possibly giving rise to the nine radial transitional fibres that seem to attach the end of the basal body to the surface of the organism. The central and secondary flagellar fibres are not present in the lumen of the basal body, but other complex structures occur there. The form of these intraluminal structures differs from genus to genus. The flagellar unit is highly asymmetrical. All the flagella examined have possessed the same one of the two possible enantiomorphic forms. At least two systems of fibres are associated with the basal bodies of all three genera.

Structural Analysis of Basal Bodies of The Isolated Oral Apparatus of Tetrahymena Pyriformis

1970 ◽  
Vol 6 (3) ◽  
pp. 679-700
Author(s):  
J. WOLFE
Keyword(s):  
Structural Analysis ◽  
Cell Membrane ◽  
Basal Body ◽  
Structural Integrity ◽  
Tetrahymena Pyriformis ◽  
Basal Plate ◽  
Basal Bodies ◽  
The Third ◽  
Ionic Detergent

The oral apparatus of Tetrahymena pyriformis was isolated using a non-ionic detergent to disrupt the cell membrane. The mouth consists largely of basal bodies and microfilaments. Each basal body is attached to the mouth by a basal plate which is integrated into the meshwork of microfilaments that confers upon the oral apparatus its structural integrity. Each basal body is composed of 9 triplet microtubules. Two of the 3 tubules, subfibres ‘A’ and ‘B’ are composed of filamentous rows of globules with a spacing of 4.5nm. The third tubule, subfibre ‘C’, is only one-third the length of the basal body.

Ciliary coordination in newt lung cells requires microtubule-based linkages between basal bodies: A correlative light and EM study

1992 ◽  
Vol 50 (1) ◽  
pp. 570-571
Author(s):  
Robert Hard ◽  
Gerald Rupp ◽  
Matthew L. Withiam-Leitch ◽  
Lisa Cardamone
Keyword(s):  
Basal Body ◽  
Untreated Control ◽  
Beat Frequency ◽  
Primary Cultures ◽  
Living Cells ◽  
Power Stroke ◽  
Ultrastructural Changes ◽  
Lung Cells ◽  
Basal Bodies ◽  
Ciliated Cells

In a coordinated field of beating cilia, the direction of the power stroke is correlated with the orientation of basal body appendages, called basal feet. In newt lung ciliated cells, adjacent basal feet are interconnected by cold-stable microtubules (basal MTs). In the present study, we investigate the hypothesis that these basal MTs stabilize ciliary distribution and alignment. To accomplish this, newt lung primary cultures were treated with the microtubule disrupting agent, Colcemid. In newt lung cultures, cilia normally disperse in a characteristic fashion as the mucociliary epithelium migrates from the tissue explant. Four arbitrary, but progressive stages of dispersion were defined and used to monitor this redistribution process. Ciliaiy beat frequency, coordination, and dispersion were assessed for 91 hrs in untreated (control) and treated cultures. When compared to controls, cilia dispersed more rapidly and ciliary coordination decreased markedly in cultures treated with Colcemid (2 mM). Correlative LM/EM was used to assess whether these effects of Colcemid were coupled to ultrastructural changes. Living cells were defined as having coordinated or uncoordinated cilia and then were processed for transmission EM.

Effects of Phonological Decoding Training on Children's Word Recognition of CVC, CV, and VC Structures

1996 ◽  
Vol 5 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Kenyatta O. Rivers ◽  
Linda J. Lombardino ◽  
Cynthia K. Thompson
Keyword(s):  
Word Recognition ◽  
Multiple Baseline ◽  
Single Subject ◽  
Group Training ◽  
Complex Structures ◽  
Multiple Baseline Design ◽  
Baseline Design ◽  
Phonological Decoding ◽  
The Third ◽  
Letter Sound

The effects of training in letter-sound correspondences and phonemic decoding (segmenting and blending skills) on three kindergartners' word recognition abilities were examined using a single-subject multiple-baseline design across behaviors and subjects. Whereas CVC pseudowords were trained, generalization to untrained CVC pseudowords, untrained CVC real words, untrained CV and VC pseudowords, and untrained CV and VC real words were assessed. Generalization occurred to all of the untrained constructions for two of the three subjects. The third subject did not show the same degree of generalization to VC pseudowords and real words; however, after three training sessions, this subject read all VC constructions with 100% accuracy. Findings are consistent with group training studies that have shown the benefits of decoding training on word recognition and spelling skills and with studies that have demonstrated the effects of generalization to less complex structures when more complex structures are trained.

scholarly journals The ultrastructure of cell division in Euglena gracilis

1978 ◽  
Vol 31 (1) ◽  
pp. 25-35
Author(s):  
M.A. Gillott ◽  
R.E. Triemer
Keyword(s):  
Cell Division ◽  
Nuclear Envelope ◽  
Basal Body ◽  
Euglena Gracilis ◽  
Equatorial Region ◽  
Basal Bodies ◽  
Cleavage Furrow ◽  
Free Zone ◽  
Prophase Nucleus

The ultrastructure of mitosis in Euglena gracilis was investigated. At preprophase the nucleus migrates anteriorly and associates with the basal bodies. Flagella and basal bodies replicate at preprophase. Cells retain motility throughout division. The reservoir and the prophase nucleus elongate perpendicular to the incipient cleavage furrow. One basal body pair surrounded by a ribosome-free zone is found at each of the nuclear poles. The spindle forms within the intact nuclear envelope- Polar fenestrae are absent. At metaphase, the endosome is elongated from pole to pole, and chromosomes are loosely arranged in the equatorial region. Distinct, trilayered kinetochores are present. Spindle elongates as chromosomes migrate to the poles forming a dumb-bell shaped nucleus by telophase. Daughter nuclei are formed by constriction of the nuclear envelope. Cytokinesis is accomplished by furrowing. Cell division in Euglena is compared with that of certain other algae.

Basal Body and Flagellar Development During the Vegetative Cell Cycle and the Sexual Cycle of Chlamydomonas Reinhardii

1974 ◽  
Vol 16 (3) ◽  
pp. 529-556 ◽  
Author(s):  
T. CAVALIER-SMITH
Keyword(s):  
Basal Body ◽  
Vegetative Cell ◽  
Amorphous Material ◽  
Sexual Cycle ◽  
Transitional Region ◽  
Basal Bodies ◽  
Vegetative Cells ◽  
Chlamydomonas Reinhardii ◽  
Body Development ◽  
Microtubular Roots

Basal body development and flagellar regression and growth in the unicellular green alga Chlamydomonas reinhardii were studied by light and electron microscopy during the vegetative cell cycle in synchronous cultures and during the sexual life cycle. Flagella regress by gradual shortening prior to vegetative cell division and also a few hours after cell fusion in the sexual cycle. In vegetative cells basal bodies remain attached to the plasma membrane by their transitional fibres and do not act as centrioles at the spindle poles during division. In zygotes the basal bodies and associated microtubular roots and cross-striated connexions all dissolve, and by 6.5 h after mating all traces of flagellar apparatus and associated structures have disappeared. They remain absent for 6 days throughout zygospore maturation and then are reassembled during zygospore germination, after meiosis has begun. Basal body assembly in developing zygospores occurs close to the plasma membrane (in the absence of pre-existing basal bodies) via an intermediate stage consisting of nine single A-tubules surrounding a central ‘cartwheel’. Assembly is similar in vegetative cells (and occurs prior to cell division), except that new basal bodies are physically attached to old ones by amorphous material. In vegetative cells, amorphous disks, which may possibly be still earlier stages in basal-body development occur in the same location as 9-singlet developing basal bodies. After the 9-singlet structure is formed, B and C fibres are added and the basal body elongates to its mature length. Microtubular roots, striated connexions and flagella are then assembled. Both flagellar regression and growth are gradual and sequential, the transitional region at the base of the flagellum being formed first and broken down last. The presence of amorphous material at the tip of the axoneme of growing and regressing flagella suggests that the axoneme grows or shortens by the sequential assembly or disassembly at its tip. In homogenized cells basal bodies remain firmly attached to each other by their striated connexions. The flagellar transitional region, and parts of the membrane and of the 4 microtubular roots, also remain attached; so also do new developing basal bodies, if present. These structures are well preserved in homogenates and new fine-structural details can be seen. These results are discussed, and lend no support to the idea that basal bodies have genetic continuity. It is suggested that basal body development can be best understood if a distinction is made between the information needed to specify the structure of a basal body and that needed to specify its location and orientation.

Localization of actin in the Tetrahymena basal body-cage complex

1992 ◽  
Vol 103 (3) ◽  
pp. 629-641 ◽  
Author(s):  
J.G. Hoey ◽  
R.H. Gavin
Keyword(s):  
Basal Body ◽  
Specific Binding ◽  
Ultrastructural Level ◽  
Basal Bodies ◽  
Muscle Actin ◽  
Cage Complex ◽  
Contractile System ◽  
Chicken Muscle ◽  
Filament Bundles

In the ciliate cytoskeleton, basal bodies are contained within separate, filamentous cages which are closely associated with basal body microtubules. We have used two polyclonal anti-actin antibodies to localize actin within the basal body-cage complex of Tetrahymena. An antiserum against a Tetrahymena oral apparatus fraction enriched for basal body proteins was produced in rabbits. Agarose-linked chicken muscle actin was used to affinity-purify anti-Tetrahymena actin antibodies from the anti-oral apparatus antiserum. Agarose-linked chicken muscle actin was used to affinity-purify anti-chicken muscle actin antibodies from a commercially available antiserum against chicken muscle actin. Both affinity-purified antibodies were monospecific for Tetrahymena actin on immunoblots containing total oral apparatus protein. The anti-actin antibodies were localized to both somatic and oral basal bodies in Tetrahymena by immunofluorescence microscopy. At the ultrastructural level with the immunogold technique, these antibodies labeled actin epitopes in four distinct regions of the basal body-cage complex: (a) basal body walls, (b) basal plate filaments, (c) proximal-end filaments and (d) cage wall filaments. In addition, the antibody labeled filament bundles that interconnect groups of basal bodies (membranelles) within the oral apparatus. Identical labeling patterns were observed with basal bodies in the isolated oral apparatus, basal bodies in the in situ oral apparatus and somatic basal bodies in situ. Quantitative analysis of gold particle distribution was used to demonstrate the specificity of the antibodies for the basal body-cage complex and to show that non-specific binding of the antibodies was negligible. Preadsorption of the antibody with muscle actin effectively eliminated the capacity of the antibody to bind to proteins on immunoblots and to basal body structures with the immunogold labeling technique. These results provide evidence for actin in the basal body-cage complex and raise the possibility of a contractile system associated with basal bodies.

Development of macrociliary cells in Beroe. I. Actin bundles and centriole migration

1988 ◽  
Vol 89 (1) ◽  
pp. 67-80
Author(s):  
S. Tamm ◽  
S.L. Tamm
Keyword(s):  
Cell Membrane ◽  
Basal Body ◽  
Actin Filaments ◽  
Close Association ◽  
Directed Assembly ◽  
Double Layers ◽  
Basal Bodies ◽  
Apical Surface ◽  
Actin Bundle ◽  
Microfilament Bundle

Differentiation of macrociliary cells on regenerating lips of the ctenophore Beroe was studied by transmission electron microscopy. In this study of early development, we found that basal bodies for macrocilia arise by an acentriolar pathway near the nucleus and Golgi apparatus, in close association with plaques of dense fibrogranular bodies. Procentrioles are often aligned side-by-side in double layers with the cartwheel ends facing outward toward the surrounding plaques of dense granules. Newly formed basal bodies then disband from groups and develop a long striated rootlet at one end. At the same time, an array of microfilaments arises in the basal cytoplasm. The microfilaments are arranged in parallel strands oriented toward the cell surface. The basal body-rootlet units are transported to the apical surface in close association with the assembling actin filament bundle. Microfilaments run parallel to and alongside the striated rootlets, to which they often appear attached. Basal body-rootlet units migrate at the heads of trails of microfilaments, as if they are pushed upwards by elongation of their attached actin filaments. Near the apical surface the actin bundle curves and runs below the cell membrane. Newly arrived basal body-rootlets tilt upwards out of the microfilament bundle to contact the cell membrane and initiate ciliogenesis. The basal bodies tilt parallel to the flat sides of the rootlets, and away from the direction in which the basal feet point. The actin bundle continues to enlarge during ciliogenesis. These results suggest that basal body migration may be driven by the directed assembly of attached actin filaments.

In vitro effects of taxol on ciliogenesis in quail oviduct

1989 ◽  
Vol 92 (1) ◽  
pp. 9-20 ◽  
Author(s):  
E. Boisvieux-Ulrich ◽  
M.C. Laine ◽  
D. Sandoz
Keyword(s):  
Basal Body ◽  
In Situ Polymerization ◽  
Neck Region ◽  
Apical Part ◽  
Transitional Region ◽  
Basal Bodies ◽  
Apical Surface ◽  
In Vitro Effects

When induced by in vivo oestrogen stimulation, ciliogenesis continues in culture in vitro of quail oviduct implants. Ultrastructure of ciliogenic cells was compared after culture for 24 or 48 h in the presence or absence of 10(−5) M-taxol. Taxol, which promotes polymerization and stabilization of microtubules, disturbed ciliogenesis, but formation of basal bodies was unaffected by the drug. Conversely, their migration towards the apical surface seemed to be slowed down or blocked and axonemal doublets polymerized onto the distal end of cytoplasmic basal bodies. They elongated and often constituted a more or less complete axoneme, extending between organelles in various orientations. These axonemes, often abnormal, were not surrounded by a membrane, with the exception of the transitional or neck region between the basal body and axoneme. The formation of membrane in this area resulted from the binding of some vesicles to the anchoring fibres of the basal body. They fused in various numbers, occasionally forming a ring, at the site of the transitional region, and exhibited the characteristics of the ciliary necklace. The association of basal bodies with vesicles or with the plasma membrane appeared to be a necessary signal for in situ polymerization of axonemal doublets. In addition, taxol induced polymerization of numerous microtubules in the cytoplasm, especially in the apical part of the cell and in the Golgi area. This network of microtubules may prevent basal body migration.

Basal body loss during fungal zoospore encystment: evidence against centriole autonomy

1986 ◽  
Vol 83 (1) ◽  
pp. 135-140
Author(s):  
I.B. Heath ◽  
S.G. Kaminskyj ◽  
T. Bauchop
Keyword(s):  
Life Cycle ◽  
Cell Line ◽  
Basal Body ◽  
Generative Cell ◽  
Basal Bodies ◽  
Cilia And Flagella ◽  
Endosymbiotic Origin

The controversial question of the possible autonomy of centrioles, as shown by the persistence of all or part of them in the generative cell line throughout the life cycle of organisms, remains unresolved. All previous reports on shedding or withdrawal of cilia and flagella showed that their basal bodies (= centrioles) were retained in the cells where they may, or may not, subsequently disassemble. We show that in the fungus Neocallimastix sp. the basal bodies are discarded with the flagella when zoospores encyst. This shedding of basal bodies argues against centriolar persistence in any form and thus against their autonomy and endosymbiotic origin.

A 210 kDa protein is located in a membrane-microtubule linker at the distal end of mature and nascent basal bodies

1999 ◽  
Vol 112 (11) ◽  
pp. 1633-1644 ◽  
Author(s):  
K.F. Lechtreck ◽  
A. Teltenkotter ◽  
A. Grunow
Keyword(s):  
Basal Body ◽  
Body Position ◽  
Immunogold Electron Microscopy ◽  
Basal Bodies ◽  
Western Blots ◽  
Whole Cells ◽  
Extracellular Matrix Components ◽  
Green Flagellate ◽  
Protein Rich ◽  
Novel Protein

A monoclonal antibody raised against purified flagellar basal apparatuses from the green flagellate Spermatozopsis similis reacted with a protein of 210 kDa (p210) in western blots. The protein was partially cloned by immunoscreening of a cDNA library. The sequence encoded a novel protein rich in alanine (25%) and proline (20%), which contained regions similar to proteins of comparable amino acid composition such as extracellular matrix components or the membrane-cytoskeletal linker synapsin. Using a polyclonal antibody (anti-p210) raised against the C-terminal part of p210, it was shown that the protein was highly enriched in the basal apparatuses. Immunogold electron microscopy of isolated cytoskeletons or whole cells revealed that p210 was located in the flagellar transition region. The protein was part of the Y-shaped fibrous linkers between the doublet microtubules and the flagellar membrane, as indicated by statistical analysis of post-labeled sections using anti-centrin and anti-tubulin as controls. In premitotic cells p210 was located in a fibrous layer at the distal end of nascent basal bodies, which was perforated by the outgrowing axoneme. During deflagellation the protein remained at the basal body but we observed changes in its distribution, indicating that p210 partially moved to the tip of the basal body. p210 can be used as a marker to determine basal body position, orientation (parallel or antiparallel) and number in S. similis by indirect immunofluorescence. We suppose that p210 is involved in linking basal bodies to the plasma membrane, which is an important step during ciliogenesis.

Sign in / Sign up

Export Citation Format

Share Document