scholarly journals THE MORPHOGENESIS OF BASAL BODIES AND ACCESSORY STRUCTURES OF THE CORTEX OF THE CILIATED PROTOZOAN TETRAHYMENA PYRIFORMIS

1969 ◽  
Vol 40 (3) ◽  
pp. 716-733 ◽  
Author(s):  
Richard D. Allen
Keyword(s):  
Basal Body ◽  
Tetrahymena Pyriformis ◽  
Basal Bodies ◽  
Proximal Surface ◽  
Body Development ◽  
Transmission Electron ◽  
Short Cylinder ◽  
Dividing Cells ◽  
Constant Distance ◽  
Single Tubules

Dividing cells of Tetrahymena pyriformis were observed by transmission electron microscopy for signs of morphogenesis of cortical structures. The earliest stage of basal body development observed was of a short cylinder of nine single tubules connected by an internal cartwheel structure. This is set perpendicular to the mature basal body at its anterior proximal surface under the transverse microtubules and next to the basal microtubules. Sequential stages show that the single tubules become triplet tubules and that the "probasal bodies" then elongate and tilt toward the organism's surface while maintaining a constant distance of 75–100 mµ with the "parent." The new basal body after it is fully extended contacts the pellicle, and then assumes a parallel orientation with and moves anterior to the parent basal body. The electron-opaque core in the lumen of the basal body and accessory structures around its outer proximal surface appear after the developing basal body has elongated. These accessory structures associating with their counterparts from other basal bodies and with the longitudinal microtubules may play a role in the final positioning of basal bodies and thus in the maintenance of cortical patterns. Observations on a second sequence of basal body formation suggest that the oral anlage arises by multiple duplication of somatic 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.

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.

The cell division cycle of Trypanosoma brucei brucei : timing of event markers and cytoskeletal modulations

1989 ◽  
Vol 323 (1218) ◽  
pp. 573-588 ◽  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Single Copy ◽  
Cell Division Cycle ◽  
Basal Bodies ◽  
Division Plane ◽  
Transmission Electron ◽  
Single Nucleus

We have analysed the timing and order of events occurring within the cell division cycle of Trypanosoma brucei . Cells in the earliest stages of the cell cycle possess a single copy of three major organelles: the nucleus, the kinetoplast and the flagellum. The first indication of progress through the cell cycle is the elongation of the pro-basal body lying adjacent to the mature basal body subtending the flagellum. This newly elongated basal body occupies a posterior position within the cell when it initiates growth of the new daughter flagellum. Genesis of two new pro-basal bodies occurs only after growth of the new daughter flagellum has been initiated. Extension of the new flagellum, together with the paraflagellar rod, then continues throughout a major portion of the cell cycle. During this period of flagellum elongation, kinetoplast division occurs and the two kinetoplasts, together with the two flagellar basal bodies, then move apart within the cell. Mitosis is then initiated and a complex pattern of organelle positions is achieved whereby a division plane runs longitudinally through the cell such that each daughter ultimately receives a single nucleus, kinetoplast and flagellum. These events have been described from observations of whole cytoskeletons by transmission electron microscopy together with detection of particular organelles by fluorescence microscopy. The order and timing of events within the cell cycle has been derived from analyses of the proportion of a given cell type occurring within an exponentially growing culture.

scholarly journals THE NUCLEIC ACIDS OF BASAL BODIES ISOLATED FROM TETRAHYMENA PYRIFORMIS

1965 ◽  
Vol 25 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Eugene J. Hoffman
Keyword(s):  
Electron Microscope ◽  
Nucleic Acids ◽  
Basal Body ◽  
Tetrahymena Pyriformis ◽  
Isolation Procedure ◽  
Basal Bodies ◽  
Phenol Extraction ◽  
Body Self

Pellicular fragments were isolated from ethanol-fixed cells of the holotrichous ciliate Tetrahymena pyriformis by the action of digitonin. The isolated pellicles were further fragmented and the basal bodies of the cilia isolated from them by three methods. The preparations, examined in the electron microscope as embedded sections or negatively stained samples, consisted mainly of somewhat deformed pellicular material, the bulk of which was basal body. DNA was determined by the diphenylamine method and by reaction with DNase, and RNA, by the orcinol method. Nucleic acids were isolated by phenol extraction and analyzed spectrophotometrically and by reaction with RNase. The assays indicated 1.2 to 2.6 per cent RNA, similar to previously published work, but only 0.0 to 1.0 per cent DNA, near enough the sensitivity limits to render the presence of DNA in the preparations uncertain. Although the isolation procedure removed nuclear contents and ribosomes, the nucleic acids could still be a residual contaminant bound to the pellicle during the isolation. Hypotheses of basal body self-duplication, moreover, can be constructed both with and without nucleic acids.

Evidence for the presence of DNA at basal body sites in Tetrahymena pyriformis

1965 ◽  
Vol 162 (989) ◽  
pp. 473-491 ◽  
Keyword(s):  
Cell Division ◽  
Basal Body ◽  
Mitotic Cycle ◽  
Tritiated Thymidine ◽  
Tetrahymena Pyriformis ◽  
Cell Cortex ◽  
Basal Bodies ◽  
Temperature Shock ◽  
Large Numbers ◽  
Order Of Magnitude

The reasons that have led to a search for DNA in the basal body of Tetrahymena pyriformis are twofold: the well-known property of proliferation of this organelle and the possibility that basal body DNA might be involved in its morphogenesis. After a brief review of earlier work the methods employed in this paper are described. To ensure large numbers of cells in a particular state of development organisms were grown in synchronized culture. Animals required for autoradiographic studies were appropriately treated with tritiated thymidine. All investigations were made on the cell cortex or 'ghost’ in order to avoid confusion from cell contents. In addition to autoradiography of ghosts, tests were made with acridine orange in the fluorescence microscope. It is concluded from fluorescence tests that basal bodies of T. pyriformis strain S contain DNA . This DNA is not detectable for the first 2h of the temperature-shock cycle, but is detect­able thereafter until cell division. The presence of DNA is confirmed by the autoradiography experiments. The amount of DNA per basal body is estimated very roughly in order of magnitude as 2 × 10 -16 g. The origin of basal body DNA is discussed and the possibilities and consequences of the existence of DNA in the homologous centriole are examined in terms of the mitotic cycle, the amoeba-flagellate transformation in Naegleria , and artificial parthenogenesis. The paper concludes with a brief discussion of the genetic implications of basal body DNA .

scholarly journals PARTIAL PURIFICATION AND PHOSPHOTUNGSTATE SOLUBILIZATION OF BASAL BODIES AND KINETODESMAL FIBERS FROM TETRAHYMENA PYRIFORMIS

1973 ◽  
Vol 57 (3) ◽  
pp. 601-612 ◽  
Author(s):  
Robert W. Rubin ◽  
William P. Cunningham
Keyword(s):  
Basal Body ◽  
Gel Electrophoresis ◽  
Sucrose Gradient ◽  
Gradient Centrifugation ◽  
Sodium Dodecyl ◽  
Tetrahymena Pyriformis ◽  
Partial Purification ◽  
Basal Bodies ◽  
Thin Sectioning ◽  
Triton X

Previously devised methods for the isolation of basal bodies from ciliate protozoans were found to be inadequate for chemical analysis. We have modified and expanded these procedures and developed a method which gives preparations containing mainly basal bodies and kinetodesmal fibers. This procedure involved fixation of cells in 30% ETOH followed by digitonin or Triton X-100 solubilization and homogenization with a Brinkmann Polytron. This is followed by sucrose gradient centrifugation. Negative staining and thin sectioning revealed these preparations to be substantially more pure than those of previous workers. It was also found that neutralized phosphotungstate (PTA) solubilized many of the components present in fixed Tetrahymena. Neutralized 1.0% PTA solubilized axonemes, cortical, axonemal, and basal body microtubules as well as kinetodesmal fibers. These results have been confirmed by both electron microscope observations and gel electrophoresis of 100,000 g supernatants of the PTA extracts. A solution of 0.1% PTA did not affect the fibers but did solubilize basal bodies. Running 1.0% PTA extracts from our basal body fractions on sodium dodecyl sulfate (SDS) polyacrylamide gels allowed us to tentatively identify the peptides of basal bodies and kinetodesmal fibers. The latter structures appear to consist of a single 21,000 mol wt peptide. These results also suggest that great caution should be taken in interpreting PTA images, especially of microtubules and axonemes.

scholarly journals REGULATION OF MICROTUBULES IN TETRAHYMENA

1973 ◽  
Vol 56 (2) ◽  
pp. 441-457 ◽  
Author(s):  
Norman E. Williams ◽  
Joseph Frankel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Body Movement ◽  
Tetrahymena Pyriformis ◽  
Basal Bodies ◽  
Amino Acid Deprivation ◽  
Transmission Electron ◽  
Late Step ◽  
Thin Walled

The coupled resorption and redifferentiation of oral structures which occurs in Tetrahymena pyriformis under conditions of amino acid deprivation has been studied by transmission electron microscopy. Two patterns of ciliary resorption have been found, (a) in situ, and (b) after withdrawal into the cytoplasm. No autophagic vacuoles containing cilia or ciliary axonemes have been seen. Stomatogenic field basal bodies arise by a process of rapid sequential nucleation, with new ones always appearing next to more mature ones, even though the latter may not be fully differentiated. Accessory radial ribbons of microtubules develop immediately adjacent to oral field basal bodies as a late step in their maturation. It can be seen that the formation of basal bodies and their orientation within the oral complex are separate processes. This is true for about 130 of the approximately 170 oral basal bodies; the remaining 40 or so form within the patterned groups of ciliary units as a later event. Clusters of randomly oriented thin-walled microtubules are found surrounding oral basal bodies at all times during stomatogenesis. They may either represent stores of microtubule subunit protein, or serve as effectors of basal body movement during their orientation into pattern.

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.

Spermatogenesis and the fine structure of the mature spermatozoon of the liver fluke, Fasciola hepatica (Trematoda: Digenea)

Parasitology ◽  
1990 ◽  
Vol 101 (3) ◽  
pp. 395-407 ◽  
Author(s):  
A. W. Stitt ◽  
I. Fairweather
Keyword(s):  
Fine Structure ◽  
Liver Fluke ◽  
Central Body ◽  
Fasciola Hepatica ◽  
Mature Spermatozoon ◽  
Basal Bodies ◽  
Nuclear Region ◽  
Sperm Ultrastructure ◽  
Transmission Electron ◽  
Median Process

SUMMARYSpermatogenesis and the fine structure of the mature spermatozoon of Fasciola hepatica have been studied by transmission electron microscopy. The primary spermatogonia display a typical gonial morphology and occupy the periphery of the testis. They undergo 3 mitotic divisions to give rise to 8 primary spermatocytes forming a rosette of cells connected to a central cytophore. The primary spermatocytes undergo 2 meiotic divisions, resulting in 32 spermatids that develop into spermatozoa. Intranuclear synaptonemal complexes in primary spermatocytes confirm the first meiotic division. The onset of spermiogenesis is marked by the formation of the zone of differentiation which contains 2 basal bodies and a further centriole derivative, the central body. The zone extends away from the spermatid cell to form the median process; into this migrates the differentiated and elongate nucleus. Simultaneously, 2 axonemes develop from the basal bodies. During development, they rotate through 90° to extend parallel to the median process. The migration of the nucleus to the distal end of the median process coincides with the fusion of the axonemes to the latter to form a monopartite spermatozoon. The mature spermatozoon possesses 2 axonemes of the 9 + ‘1’ pattern typical of parasitic platyhelminths, 2 elongate mitochondria and a variable array of peripheral microtubules. The nuclear region of the spermatozoon is immotile. The value of sperm ultrastructure as a taxonomic tool in platyhelminth phylogeny is discussed.

Freeze-fracture analysis of membrane events during early neogenesis of cilia in Tetrahymena: changes in fairy-ring morphology and membrane topography

1983 ◽  
Vol 60 (1) ◽  
pp. 137-156
Author(s):  
L.A. Hufnagel
Keyword(s):  
Cell Division ◽  
Membrane Structure ◽  
Freeze Fracture ◽  
Fracture Analysis ◽  
Basal Bodies ◽  
Membrane Topography ◽  
Fairy Rings ◽  
Dividing Cells ◽  
Cortical System ◽  
Membrane Particle

A freeze-fracture analysis of early neogenesis of somatic and oral cilia of Tetrahymena was conducted using exponentially grown cultures and also cells induced to undergo oral reorganization. In this report, presumptive ciliary domains (PCDs), sites of future outgrowth of somatic cilia, are identified and their membrane structure is described in detail. The fairy ring, an array of membrane particles that occurs within the PCD and appears to be a precursor of the ciliary necklace, is described. A sequence of early stages in the formation of the ciliary necklace of somatic cilia is deduced from topographical information and membrane particle arrangements and numbers. Evidence is presented that basal bodies are seated at the cell surface prior to initiation of necklace assembly and a possible role for the basal body in necklace assembly is suggested. In dividing cells, new oral cilia grow out prior to orientation of cilia-parasomal sac complexes relative to cell axes. In dividing cells and during oral reorganization, new cilia also develop prior to their alignment into membranelles. Thus, growth of cilia is independent of their spatial orientation. Fairy rings were not observed during oral reorganization. During cell division, proliferation of new cilia is accompanied by the formation of a network of junctions between a cortical system of membranous cisternae, the cortical ‘alveoli’. These interalveolar junctions may serve as tracks for early positioning and orientation of new oral basal bodies.

Sign in / Sign up

Export Citation Format

Share Document