scholarly journals THE FINE STRUCTURE OF THE NUCLEI OF TETRAHYMENA PYRIFORMIS THROUGHOUT THE CELL CYCLE

1965 ◽  
Vol 27 (3) ◽  
pp. 519-529 ◽  
Author(s):  
Charles J. Flickinger
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Fine Structure ◽  
Dna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Concomitant Increase

The fine structure of the nuclei of logarithmically growing Tetrahymena pyriformis, strain HSM, was studied at 30-minute intervals throughout the cell cycle. Organisms were selected at similar stages of cytokinesis by means of a braking pipette, incubated, fixed in OsO4, and embedded in agar to facilitate subsequent preparation for electron microscopy. Aggregates of micronuclear chromatin underwent a decrease in density and number with a concomitant increase in size throughout interphase. There were no impressive changes in macronuclear morphology. It was found possible to estimate a cell's progress through interphase by observation of micronuclear morphology, but attempts to correlate changes in fine structure with periods of DNA synthesis were unsuccessful.

scholarly journals THE SYNTHESIS OF MICROTUBULE AND OTHER PROTEINS OF THE ORAL APPARATUS IN TETRAHYMENA PYRIFORMIS

1971 ◽  
Vol 50 (3) ◽  
pp. 709-720 ◽  
Author(s):  
John Rannestad ◽  
Norman E. Williams
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Acetic Acid ◽  
Tetrahymena Pyriformis ◽  
Basal Bodies

Several proteins, including microtubule proteins, have been isolated from the oral apparatus of the ciliate Tetrahymena. The synthesis of these proteins has been studied in relation to formation of this organelle system by the cell. Electron microscopy has shown that the isolated oral apparatus consists primarily of basal bodies, pellicular membranes, and a system of subpellicular microtubules and filaments. Cilia were removed during the isolation; therefore none of the proteins studied was from these structures. Evidence was obtained from the study of total oral apparatus protein which indicates that at least some of the proteins involved in formation of this organelle system may be synthesized and stored in the cytoplasm for use over long periods. This pattern of regulation was found for three individual proteins isolated from the oral apparatus fraction after extraction with a phenol-acetic acid solvent. A different pattern of regulation was found for microtubule proteins isolated from the oral apparatus of Tetrahymena. The data suggest that microtubule proteins, at least in logarithmically growing cells, are not stored in a cytoplasmic pool but are synthesized in the same cell cycle in which they are assembled into oral structures.

scholarly journals Causal relations among cell cycle processes in Tetrahymena pyriformis. An analysis employing temperature-sensitive mutants.

1976 ◽  
Vol 71 (1) ◽  
pp. 242-260 ◽  
Author(s):  
J Frankel ◽  
L M Jenkins ◽  
L E DeBault
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Developmental Pathway ◽  
Temperature Sensitive Mutants ◽  
Oral Development ◽  
Macronuclear Division

Utilization of temperature-sensitive mutants of Tetrahymena pyriformis affected in cell division or developmental pathway selection has permitted elucidation of causal dependencies interrelating micronuclear and macronuclear replication and division, oral development, and cytokinesis. In those mutants in which cell division is specifically blocked at restrictive temperatures, micronuclear division proceeds with somewhat accelerated periodicity but maintains normal coupling to predivision oral development. Macronuclear division is almost totally suppressed in an early acting mutant (mola) that prevents formation of the fission zone, and is variably affected in other mutants (such as mo3) that allow the fission zone to form but arrest constriction. However, macronuclear DNA synthesis can proceed for about four cycles in the nondividing mutant cells. A second class of mutants (psm) undergoes a switch of developmental pathway such that cells fail to enter division but instead repeatedly carry out an unusual type of oral replacement while growing in nutrient medium at the restrictive temperature. Under these circumstances no nuclei divide, yet macronuclear DNA accumulation continues. These results suggest that (a) macronuclear division is stringently affected by restriction of cell division, (b) micronuclear division and replication can continue in cells that are undergoing the type of oral development that is characteristic of division cycles, and (c) macronuclear DNA synthesis can continue in growing cells regardless of their developmental status. The observed relationships among events are consistent with the further suggestion that the cell cycle in this organism may consist of separate clusters of events. with a varying degree of coupling among clusters. A minimal model of the Tetrahymena cell cycle that takes these phenomena into account is suggested.

scholarly journals H3-THYMIDINE DERIVATIVE POOLS IN RELATION TO MACRONUCLEAR DNA SYNTHESIS IN TETRAHYMENA PYRIFORMIS

1965 ◽  
Vol 25 (2) ◽  
pp. 171-177 ◽  
Author(s):  
G. E. Stone ◽  
O. L. Miller ◽  
D. M. Prescott
Keyword(s):  
Cell Cycle ◽  
Life Cycle ◽  
Dna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Water Soluble ◽  
Cell Life ◽  
A Cell ◽  
S Period ◽  
Autoradiographic Technique ◽  
Turn Over

The formation of a soluble H3-thymidine derivative pool has been examined in Tetrahymena pyriformis as a function of macronuclear DNA synthesis during the cell life cycle. An autoradiographic technique which allows the detection of water-soluble materials within a cell has shown that these cells do not take up and retain exogenous H3-thymidine during G1 or G2. Uptake of H3-thymidine is restricted to the S period of the cell cycle. Additional autoradiographic experiments show, however, that a soluble pool of H3-thymidine derivatives persists from the end of one DNA synthesis period to the beginning of the next synthesis period in the subsequent cell cycle. Since this persisting pool cannot be labeled with H3-thymidine, the pool does not turn over during non-S periods.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

Fibroblasts During Hypertrophic Scar Formation and Resolution

1973 ◽  
Vol 31 ◽  
pp. 428-429
Author(s):  
C. W. Kischer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Fine Structure ◽  
Metabolic Activity ◽  
Hypertrophic Scar ◽  
Normal Skin ◽  
Ground Substance ◽  
Hypertrophic Scars ◽  
Scanning Electron

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).

Effects of Hypophysectomy on the Fine Structure of Rat Liver Cells

1967 ◽  
Vol 25 ◽  
pp. 156-157
Author(s):  
Robert R. Cardell
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Rat Liver ◽  
Liver Cell ◽  
Anterior Pituitary ◽  
Liver Cells ◽  
Biochemical Studies ◽  
Liver Functions ◽  
Rat Liver Cells ◽  
And Control

Hypophysectomy of the rat renders this animal deficient in the hormones of the anterior pituitary gland, thus causing many primary and secondary hormonal effects on basic liver functions. Biochemical studies of these alterations in the rat liver cell are quite extensive; however, relatively few morphological observations on such cells have been recorded. Because the available biochemical information was derived mostly from disrupted and fractionated liver cells, it seemed desirable to examine the problem with the techniques of electron microscopy in order to see what changes are apparent in the intact liver cell after hypophysectomy. Accordingly, liver cells from rats which had been hypophysectomized 5-120 days before sacrifice were studied. Sham-operated rats served as controls and both hypophysectomized and control rats were fasted 15 hours before sacrifice.

Ultrastructure of the soil fungus, Geomyces pannorus

1984 ◽  
Vol 42 ◽  
pp. 738-739
Author(s):  
J. A. Traquair ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Low Temperatures ◽  
Soil Fungus ◽  
Organic Soils ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

Albumin-Induced Endocytic Vacuoles in Tetrahymena Pyrijormis

1975 ◽  
Vol 33 ◽  
pp. 694-695
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Protein Concentration ◽  
Tetrahymena Pyriformis ◽  
Sequence Of Events ◽  
Cytoplasmic Bodies ◽  
Food Vacuoles ◽  
Mouse Ascites ◽  
Normal Human

Exposure of the ciliate, Tetrahymena pyriformis, strain WH6, to normal human or rabbit sera or mouse ascites fluids induces the formation of large cytoplasmic bodies. By electron microscopy these (LB) are observed to be membrane-bounded structures, generally spherical and varying in size (Fig. 1), which do not resemble the food vacuoles of cells grown in proteinaceous broth. The possibility exists that the large bodies represent endocytic vacuoles containing material concentrated from the highly nutritive proteins and lipoproteins of the sera or ascites fluids. Tetrahymena mixed with bovine serum albumin or ovalbumin solutions having about the same protein concentration (7g/100 ml) as serum form endocytic vacuoles which bear little resemblance to the serum-induced LB. The albumin-induced structures (Fig. 2) are irregular in shape, rarely spherical, and have contents which vary in density and consistency. In this paper an attempt is made to formulate the sequence of events which might occur in the formation of the albumin-induced vacuoles.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

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