scholarly journals DEVELOPMENT OF THE FLAGELLAR APPARATUS OF NAEGLERIA

1966 ◽  
Vol 31 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Allan D. Dingle ◽  
Chandler Fulton
Keyword(s):  
Cell Membrane ◽  
Cell Surface ◽  
Basal Body ◽  
Flagellar Apparatus ◽  
Basal Bodies ◽  
Naegleria Gruberi

Flagellates of Naegleria gruberi have an interconnected flagellar apparatus consisting of nucleus, rhizoplast and accessory filaments, basal bodies, and flagella. The structures of these components have been found to be similar to those in other flagellates. The development of methods for obtaining the relatively synchronous transformation of populations of Naegleria amebae into flagellates has permitted a study of the development of the flagellar apparatus. No indications of rhizoplast, basal body, or flagellum structures could be detected in amebae. A basal body appears and assumes a position at the cell surface with its filaments perpendicular to the cell membrane. Axoneme filaments extend from the basal body filaments into a progressive evagination of the cell membrane which becomes the flagellum sheath. Continued elongation of the axoneme filaments leads to differentiation of a fully formed flagellum with a typical "9 + 2" organization, within 10 min after the appearance of basal bodies.

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.

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.

The ultrastructure of the somatic cortex of Pseudomicrothorax dubius: structure and function of the epiplasm in ciliated protozoa

1977 ◽  
Vol 25 (1) ◽  
pp. 367-385
Author(s):  
R.K. Peck
Keyword(s):  
Cell Surface ◽  
Basal Body ◽  
Structure And Function ◽  
Basal Bodies ◽  
Ciliated Protozoa ◽  
Somatic Cortex ◽  
And Function

The ultrastructure of the somatic cortex of the ciliate Pseudomicrothorax dubius is studied with emphasis on the epiplasm layer which lies immediately under the inner alveolar membrane and is continuous with the terminal plates of cortical basal bodies. In addition to a clearly demonstrable cytoskeletal role, the epiplasm appears to function as a comenting substance which integrates numerous cortical fibres and membranes. The kinetodesmal, postciliary and transverse fibre systems which originate at the proximal ends of basal bodies extend toward the cell surface and end at or in the epiplasm. Inner alveolar membranes and trichocyst membranes are attached to the epiplasm. Basal bodies are anchored into the epiplasm via their terminal plates. The epiplasm appears to be morphogenetically important as a matrix into which newly formed basal bodies insert. Electron-opaque arms occur at the terminal plate level of new basal bodies, and these arms fuse with the epiplasm when basal body insertion occurs. The position of trichocysts in the cortex is specified by the epiplasm. Evidence from numerous other ciliates tends to confirm both structural and morphogenetic roles of the epiplasm.

scholarly journals THE RELATIONSHIP BETWEEN THE FINE STRUCTURE AND DIRECTION OF BEAT IN GILL CILIA OF A LAMELLIBRANCH MOLLUSC

1961 ◽  
Vol 11 (1) ◽  
pp. 179-205 ◽  
Author(s):  
I. R. Gibbons
Keyword(s):  
Fine Structure ◽  
Cell Surface ◽  
Basal Body ◽  
Transitional Region ◽  
Basal Bodies ◽  
Conical Structure ◽  
The Relationship ◽  
Basal Foot ◽  
Different Levels ◽  
Outer Fiber

This paper describes the fine structure and its relationship to the direction of beat in four types of cilia on the gill of the fresh-water mussel Anodonta cataracta. The cilia contain nine outer, nine secondary, and two central fibers, such as have been described previously in other material. Each outer fiber is a doublet with one subfiber bearing arms. One particular pair of outer fibers (numbers 5 and 6) are joined together by a bridge. The two central fibers are enclosed by a central sheath; also present in this region is a single, small mid-fiber. The different groups of fibers are connected together by radial links that extend from the outer to the secondary fibers, and from the secondary fibers to the central sheath. The basal body consists of a cylinder of nine triplet fibers. Projecting from it on one side is a dense conical structure called the basal foot. The cylinder of outer fibers continues from the basal body into the cilium, passing through a complex transitional region in which five distinct changes of structure occur at different levels. There are two sets of fibers associated with the basal bodies: a pair of striated rootlets that extends from each basal body down into the cell, and a system of fine tubular fibers that runs parallel to the cell surface. The relationship between fine structure and direction of beat is the same in all four types of cilia examined. The plane of beat is perpendicular to the plane of the central fibers, with the effective stroke toward the bridge between outer fibers 5 and 6, and toward the foot on the basal body.

scholarly journals De novo formation of basal bodies in Naegleria gruberi

2005 ◽  
Vol 169 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Hong-Kyung Kim ◽  
Jeong-Gu Kang ◽  
Shigehiko Yumura ◽  
Charles J. Walsh ◽  
Jin Won Cho ◽  
...  
Keyword(s):  
Western Blotting ◽  
Basal Body ◽  
Gel Electrophoresis ◽  
De Novo ◽  
Myosin Ii ◽  
Basal Bodies ◽  
2D Gel Electrophoresis ◽  
2D Gel ◽  
Naegleria Gruberi

The de novo formation of basal bodies in Naegleria gruberi was preceded by the transient formation of a microtubule (MT)-nucleating complex containing γ-tubulin, pericentrin, and myosin II complex (GPM complex). The MT-nucleating activity of GPM complexes was maximal just before the formation of visible basal bodies and then rapidly decreased. The regulation of MT-nucleating activity of GPM complexes was accomplished by a transient phosphorylation of the complex. Inhibition of dephosphorylation after the formation of basal bodies resulted in the formation of multiple flagella. 2D-gel electrophoresis and Western blotting showed a parallel relationship between the MT-nucleating activity of GPM complexes and the presence of hyperphosphorylated γ-tubulin in the complexes. These data suggest that the nucleation of MTs by GPM complexes precedes the de novo formation of basal bodies and that the regulation of MT-nucleating activity of GPM complexes is essential to the regulation of basal body number.

Ultrastructure and development of the flagellar apparatus and flagellar motion in the colonial graeen alga Astrephomene gubernaculifera

1983 ◽  
Vol 63 (1) ◽  
pp. 21-41
Author(s):  
H.J. Hoops ◽  
G.L. Floyd
Keyword(s):  
Basal Body ◽  
Rotational Symmetry ◽  
Amorphous Material ◽  
Flagellar Apparatus ◽  
The Other ◽  
Basal Bodies ◽  
Mature Cell ◽  
Embryonic Cleavage ◽  
Development Proceeds ◽  
Concurrent Events

Immediately following embryonic cleavage, the cells of Astrephomene have four equal-sized basal bodies, two of which are connected by a striated distal fibre and two striated proximal fibres. The four microtubular rootlets, which alternate between having 3/1 and 2 members, are arranged cruciately. The two basal bodies that are connected by the striated fibres then extend into flagella, while the two accessory basal bodies are now markedly shorter. At this stage the flagellar apparatus has 180 degrees rotational symmetry and is very similar to the flagellar apparatus of the unicellular Chlamydomonas and related algae. Development proceeds with a number of concurrent events. The basal bodies begin to separate at their proximal ends and become nearly parallel. Each striated proximal fibre detaches at one end from one of the basal bodies. Each half of the flagellar apparatus, which consists of a flagellum and attached basal body, an accessory basal body, two rootlets and a striated fibre (formerly one of the proximal striated fibres), rotates about 90 degrees, the two halves rotating in opposite directions. An electron-dense strut forms near one two-membered rootlet and grows past both basal bodies. During this time a fine, fibrous component appears between newly developed spade-like structures and associated amorphous material connected to each basal body. The basal bodies continue to separate as the distal fibre stretches and finally detaches from one of them. These processes result in the loss of the 180 degree rotational symmetry present in previous stages. Although the flagella continue to separate, there is no further reorganization of the components of the flagellar apparatus. In the mature cell of Astrephomene, the two flagella are inserted separately and are parallel. The four microtubular rootlets are no longer arranged cruciately. Three of the rootlets are nearly parallel, while the fourth is approximately perpendicular to the other three. A straited fibre connects each basal body to the underside of the strut. These fibres run in the direction of the effective stroke of the flagella and might be important either in anchoring the basal bodies or in the initiation of flagellar motion. Unlike the case in the unicellular Chlamydomonas, the two flagella beat in the same direction and in parallel planes. The flagella of a given cell may or may not beat in synchrony. The combination of this type of flagellar motion and the parallel, separate flagella appears to be suited to the motion of this colonial organism.

The ultrastructure of Ulothrix mucosa. II. The flagellar apparatus of the zoospore

1986 ◽  
Vol 64 (1) ◽  
pp. 166-176 ◽  
Author(s):  
G. M. Lokhorst ◽  
W. Star
Keyword(s):  
Basal Body ◽  
Spatial Configuration ◽  
Rotational Symmetry ◽  
Flagellar Apparatus ◽  
Taxonomic Status ◽  
Proximal Region ◽  
Basal Bodies ◽  
Serial Sectioning ◽  
Counterclockwise Direction ◽  
Microtubular Roots

The actual spatial configuration of the flagellar apparatus of the quadriflagellate zoospore of Ulothrix mucosa Thuret has been reconstructed by serial sectioning analysis. This apparatus shows an architecture quite similar to that found in related Ulvophyceae. Common characteristics are the differently leveled basal body pairs; the 180° rotational symmetry of the flagellar apparatus; the proximal overlap of the upper basal bodies which are displaced with respect to each other in the counterclockwise direction; terminal caps; four cruciately arranged microtubular roots (R2, R4); a distinctly striated distal connecting fibre that interconnects the upper basal bodies; and striated bands (SB1) that join the R4s to the lower basal bodies. Specific features are the arrangement of the R4 in a three over one configuration when entering the proximal region of the flagellar apparatus; the differently shaped proximal sheaths and their association with a proximal sheath connecting band; the presence of two system II fibres (rhizoplasts) which arise from the lower basal body pair; the striated bands (SB2) that connect the R2s to the lower basal bodies; the distinct striation of the system I fibre, which is not only intimately associated with the R2, but also with the R4 (not earlier reported for an ulvophycean alga); and, finally, the relevant displacement of the lower basal body pair in a counterclockwise direction of approximately half a basal body diameter. In light of these findings the taxonomic status of the Ulotrichales as well as of the Ulvophyceae is discussed.

scholarly journals An analogue-sensitive approach identifies basal body rotation and flagellum attachment zone elongation as key functions of PLK in Trypanosoma brucei

2013 ◽  
Vol 24 (9) ◽  
pp. 1321-1333 ◽  
Author(s):  
Ana Lozano-Núñez ◽  
Kyojiro N. Ikeda ◽  
Thomas Sauer ◽  
Christopher L. de Graffenried
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Rna Interference ◽  
Cell Surface ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Basal Bodies ◽  
Body Rotation ◽  
The Many ◽  
Attachment Zone

Polo-like kinases are important regulators of cell division, playing diverse roles in mitosis and cytoskeletal inheritance. In the parasite Trypanosoma brucei, the single PLK homologue TbPLK is necessary for the assembly of a series of essential organelles that position and adhere the flagellum to the cell surface. Previous work relied on RNA interference or inhibitors of undefined specificity to inhibit TbPLK, both of which have significant experimental limitations. Here we use an analogue-sensitive approach to selectively and acutely inhibit TbPLK. T. brucei cells expressing only analogue-sensitive TbPLK (TbPLKas) grow normally, but upon treatment with inhibitor develop defects in flagellar attachment and cytokinesis. TbPLK cannot migrate effectively when inhibited and remains trapped in the posterior of the cell throughout the cell cycle. Using synchronized cells, we show that active TbPLK is a direct requirement for the assembly and extension of the flagellum attachment zone, which adheres the flagellum to the cell surface, and for the rotation of the duplicated basal bodies, which positions the new flagellum so that it can extend without impinging on the old flagellum. This approach should be applicable to the many kinases found in the T. brucei genome that lack an ascribed function.

scholarly journals WDR5 stabilizes actin architecture to promote multiciliated cell formation

2017 ◽  
Author(s):  
Saurabh S. Kulkarni ◽  
John N. Griffin ◽  
Karel F. Liem ◽  
Mustafa K. Khokha
Keyword(s):  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Basal Body ◽  
Chromatin Modification ◽  
Cell Formation ◽  
Basal Bodies ◽  
Actin Network ◽  
Tissue Morphogenesis ◽  
Multiciliated Cells ◽  
Intracellular Organelles

The actin cytoskeleton is critical to shape cells and pattern intracellular organelles to drive tissue morphogenesis. In multiciliated cells (MCCs), apical actin forms a lattice that drives expansion of the cell surface necessary to host hundreds of cilia. The actin lattice also uniformly distributes basal bodies across this surface. This apical actin network is dynamically remodeled, but the molecules that regulate its architecture remain poorly understood. We identify the chromatin modifier, WDR5, as a regulator of apical F-actin in multiciliated cells. Unexpectedly, WDR5 functions independently of chromatin modification in MCCs. Instead, we discover a scaffolding role for WDR5 between the basal body and F-actin. Specifically, WDR5 binds to basal bodies and migrates apically, where F-actin organizes around WDR5. Using a monomer trap for G-actin, we show that WDR5 stabilizes F-actin to maintain apical lattice architecture. In summary, we identify a novel, non-chromatin role for WDR5 in stabilizing F-actin in multiciliated cells.

scholarly journals Naegleria gruberi De Novo Basal Body Assembly Occurs via Stepwise Incorporation of Conserved Proteins

2010 ◽  
Vol 9 (6) ◽  
pp. 860-865 ◽  
Author(s):  
Lillian K. Fritz-Laylin ◽  
Zoe June Assaf ◽  
Sean Chen ◽  
W. Zacheus Cande
Keyword(s):  
Basal Body ◽  
De Novo ◽  
Unicellular Eukaryote ◽  
Basal Bodies ◽  
Microtubule Cytoskeleton ◽  
Cytoplasmic Microtubule ◽  
Content Type ◽  
Genes Encoding ◽  
Associated Proteins ◽  
Naegleria Gruberi

ABSTRACT Centrioles and basal bodies are discrete structures composed of a cylinder of nine microtubule triplets and associated proteins. Metazoan centrioles can be found at mitotic spindle poles and are called basal bodies when used to organize microtubules to form the core structure of flagella. Naegleria gruberi, a unicellular eukaryote, grows as an amoeba that lacks a cytoplasmic microtubule cytoskeleton. When stressed, Naegleria rapidly (and synchronously) differentiates into a flagellate, forming a complete cytoplasmic cytoskeleton de novo, including two basal bodies and flagella. Here, we show that Naegleria has genes encoding conserved centriole proteins. Using novel antibodies, we describe the localization of three centrosomal protein homologs (SAS-6, γ-tubulin, and centrin-1) during the assembly of the flagellate microtubule cytoskeleton. We also used these antibodies to show that Naegleria expresses the proteins in the same order as their incorporation into basal bodies, with SAS-6 localizing first, followed by centrin and finally γ-tubulin. The similarities between basal body assembly in Naegleria and centriole assembly in animals indicate that mechanisms of assembly, as well as structure, have been conserved throughout eukaryotic evolution.

Sign in / Sign up

Export Citation Format

Share Document