Cell Multiplication in Tetrahymena Cultures after Addition of Particulate Material

1973 ◽  
Vol 12 (1) ◽  
pp. 275-286
Author(s):  
L. RASMUSSEN ◽  
L. MODEWEG-HANSEN
Keyword(s):  
Tetrahymena Pyriformis ◽  
Food Vacuole ◽  
Particulate Material ◽  
Cell Multiplication ◽  
Particulate Suspensions ◽  
Proteose Peptone ◽  
Generation Times ◽  
Food Vacuoles ◽  
Net Charges ◽  
Peptone Broth

We have studied the effects of adding particulate supplements to populations of Tetrahymena pyriformis in 2% sterile-filtered proteose peptone broth which supports cell multiplication poorly (generation times in excess of 40 h). The tested compounds were: heat-sterilized suspensions of egg albumin, nutritionally inert particles of polystyrene, sulphopropyl and quarternary amino-ethyl substituted dextran (in concentrations of 4, 40 and 400 µg per ml). The particles had approximately the same size, but differed in their electric net charges. Particulate suspensions of 40 µg per ml or more greatly improved cell multiplication rates (generation times about 6 h). It is probable that the effect of the particles is to induce formation of food vacuoles without which cell multiplication and growth is very slow. The contribution of the food vacuole to nutrient uptake in Tetrahymena is discussed.

Cytochalasin B: Aspects of Phagocytosis in Nutrient Uptake in Tetrahymena

1974 ◽  
Vol 15 (2) ◽  
pp. 403-406
Author(s):  
ELSE K. HOFFMANN ◽  
L. RASMUSSEN ◽  
E. ZEUTHEN
Keyword(s):  
Nutrient Uptake ◽  
Nutrient Medium ◽  
Cytochalasin B ◽  
Tetrahymena Pyriformis ◽  
Food Vacuole ◽  
Vacuole Formation ◽  
Proteose Peptone ◽  
High Concentrations

Cytochalasin B (37 µg per ml) reduces the rate of food vacuole formation, i.e. the rate of phagocytosis, in Tetrahymena pyriformis. Cytochalasin B in this concentration suppresses multiplication rates in a nutrient medium consisting of 2 % proteose peptone, but multiplication is unaffected if this medium is supplemented with glucose and high concentrations of nucleosides. Thus nutrients in high concentrations circumvent the necessity for phagocytosis in Tetrahymena.

Membrane recycling at the cytoproct of Tetrahymena

1979 ◽  
Vol 35 (1) ◽  
pp. 217-227
Author(s):  
R.D. Allen ◽  
R.W. Wolf
Keyword(s):  
Plasma Membrane ◽  
Single Cells ◽  
Tetrahymena Pyriformis ◽  
Food Vacuole ◽  
Membrane Recycling ◽  
Vacuole Membrane ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Food Vacuoles ◽  
Spherical Vesicles

Exocytosis and membrane recycling at the cytoproct (cell anus) of Tetrahymena pyriformis were studied using thin-section electron microscopy. Single cells were fixed at specific times relative to the elimination of the vacuole's contents—before elimination, at elimination, 3–5 s and 10–15 s following elimination. The closed cytoproct is distinguished from other pellicular regions by a single membrane at the cell surface which is circumscribed by an electron-opaque flange that links or welds the plasma membrane to the underlying alveolar margins. Microtubules originating in the flange pass inward where they lie over, and possibly guide, the approaching food vacuoles to the cytoproct. Food facuoles near the cytoproct are also accompanied by coats of microfilaments. These microfilaments appear to be active in the channelling and endocytosis of food vacuole membrane. Upon cytoproct opening the plasma membrane and food vacuole membrane fuse. Elimination seems to be essentially passive and is accomplished by re-engulfment of the old food vacuole membrane which is constantly associated with microfilaments. Reengulfment of all the food vacuole membrane requires 10–15 s and results in a closed cytoproct. The membrane remnants embedded in microfilaments form a cluster under the closed cytoproct. At the periphery of this cluster remnants take the shape of 70–130-nm spherical vesicles or 0.2-micrometer-long flattened vesicles.

Serum-Induced Endocytic Vacuole in the Nonphagocytic Tetrahymena Pyriformis Strain NP1

1977 ◽  
Vol 35 ◽  
pp. 644-645
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Electron Microscopy ◽  
Large Body ◽  
Tetrahymena Pyriformis ◽  
Metal Salts ◽  
Proteose Peptone ◽  
Transmission Electron ◽  
Food Vacuoles ◽  
Heavy Metal Salts ◽  
Normal Human ◽  
Peptone Medium

Tetrahymena pyriformis strains WH6, W, HSM, and GLC, after exposure to normal human serum, give rise to large membrane-bounded endocytic vacuoles, as visualized by transmission electron microscopy (TEM). These vacuoles do not resemble ordinary food vacuoles formed in the oral apparatus. Nor do they appear to be vacuoles containing protein concentrated from the serum: Albumin solutions induce a different type of vacuole (Brenner et al., 1976). The large bodies take a stain (PAS) that indicates the presence of polysaccharide. TEM micrographs show the presence of lipid in some of the large bodies. It is not yet known if these large body vacuoles are formed in the oral apparatus like food vacuoles or result from the fusion of pinocytic vacuoles.Although the mutant T. pyriformis strain, NP1, is unable to form a functional oral apparatus at 37° C and cannot form food vacuoles (Rasmussen and Orias, 1975), it multiplies in 2% proteose peptone medium supplemented with vitamins and heavy metal salts.

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.

Intracellular distribution of lead in Tetrahymena during continuous exposure to the metal

1979 ◽  
Vol 39 (1) ◽  
pp. 383-396
Author(s):  
J.R. Nilsson
Keyword(s):  
Cell Growth ◽  
Growth Medium ◽  
Food Vacuole ◽  
Continuous Exposure ◽  
Organic Growth ◽  
Food Vacuoles ◽  
Entire Cell ◽  
Membrane Bound ◽  
Lag Period ◽  
High Concentrations

Lead acetate (0.1–0.2%) forms a precipitate with the organic growth medium. The Tetrahymena cells ingest this lead-containing precipitate and cell growth is resumed after a variable lag period. Ingested lead is observed as electron-dense material in food vacuoles. Soon after exposure, cytoplasmic lead (preserved with certain fixation only) is revealed as electron-dense particles in cilia and in a halo around digestive vacuoles. Later the lead particles pervade the entire cell but after the lag period they are confined to membrane-bound spaces. In dilute growth medium, high concentrations of lead inhibit food-vacuole formation and cell growth. Under these conditions lead is deposited in alveoli of the pellicle and is also found in autophagic vacuoles and other membrane-limited structures. The study has revealed that lead enters Tetrahymena through the membrane of digestive vacuoles and through the cell surface. The change in distribution of lead during the lag period indicates that a mechanism is activated for removal of lead into membrane-bound spaces. The final storage of lead seems to be in lysosomes.

Die Bildung von Thymidintriphosphat bei Tetrahymena pyriformis (EHRENBERG) in statistischen und hitzesynchronisierten Kulturen / Formation of Thymidine Triphosphate in statistical and heat synchronized cultures of Tetrahymena pyriformis (EHRENBERG)

1970 ◽  
Vol 25 (5) ◽  
pp. 517-521 ◽  
Author(s):  
Manfred K. Grieshaber ◽  
Franz Duspiva
Keyword(s):  
Heat Treatment ◽  
Enzyme Activity ◽  
Stationary Phase ◽  
Dna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Thymidylate Kinase ◽  
Proteose Peptone ◽  
Thymidine Triphosphate ◽  
Logarithmic Growth ◽  
Synchronized Cultures

The activity of thymidylate kinase is correlated with DNA-synthesis in Tetrahymena. During logarithmic growth it is twice as high as in the stationary phase; in cultures synchronized by heat treatment, the activity of the enzyme increases with the onset of DNA-synthesis. After application of 5 x 10-6 ᴍ Methotrexate, the activity of thymidylate kinase remains unchanged. There is, however, a dramatic increase in enzyme activity when the inhibition of transmethylations is circumvened by adding thymidine and proteose-peptone.

scholarly journals DIGESTION AND THE DISTRIBUTION OF ACID PHOSPHATASE IN BLEPHARISMA

1968 ◽  
Vol 37 (2) ◽  
pp. 329-344 ◽  
Author(s):  
Herbert M. Dembitzer
Keyword(s):  
Electron Microscopy ◽  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Acid Phosphatase Activity ◽  
Food Vacuole ◽  
Vacuolar Membrane ◽  
Latex Particles ◽  
Pinocytotic Vesicles ◽  
Food Vacuoles ◽  
Separate System

Suspensions of Blepharisma intermedium were fed latex particles for 5 min and then were separated from the particles by filtration. Samples were fixed at intervals after separation and incubated to demonstrate acid phosphatase activity. They were subsequently embedded and sectioned for electron microscopy. During formation of the food vacuole, the vacuolar membrane is acid phosphatase-negative. Within 5 min, dumbbell-shaped acid phosphatase-positive bodies, possibly derived from the the acid phosphatase-positive Golgi apparatus, apparently fuse with the food vacuole and render it acid phosphatase-positive. A larger type of acid phosphatase-positive, vacuolated body may also fuse with the food vacuole at later stages. At about 20 min after formation, acid phosphatase-positive secondary pinocytotic vesicles pinch off from the food vacuoles and approach a separate system of membrane-bounded spaces. By 1 hr after formation, the food vacuole becomes acid phosphatase-negative, and the undigested latex particles are voided into the membrane-bounded spaces. The membrane-bounded spaces are closely associated with the food vacuole at all stages of digestion and are generally acid phosphatase-negative. Within the membrane-bounded spaces, dense, pleomorphic, granular bodies are found, in which are embedded mitochondria, paraglycogen granules, membrane-limited acid phosphatase-containing structures, and Golgi apparatuses. The granular bodies may serve as vehicles for the transport of organelles through the extensive, ramifying membrane-bounded spaces.

scholarly journals USE OF GENOMIC EXCLUSION TO ISOLATE HEAT-SENSITIVE MUTANTS IN TETRAHYMENA

Genetics ◽  
1973 ◽  
Vol 73 (4) ◽  
pp. 543-559
Author(s):  
Eduardo Orias ◽  
Miriam Flacks
Keyword(s):  
Room Temperature ◽  
Axenic Culture ◽  
Tetrahymena Pyriformis ◽  
Recessive Mutation ◽  
Allelic Exclusion ◽  
Current Interest ◽  
Proteose Peptone ◽  
Abnormal Form ◽  
Mutant Strains ◽  
Peptone Medium

ABSTRACT We have used the abnormal form of conjugation known as "genomic exclusion" to isolate a collection of heat-sensitive mutants of Tetrahymena pyriformis, syngen 1. Growth at room temperature in bacterized medium and no growth at 40°C in the same medium was the criterion used for the isolation. The mutant strains were tested for growth in pure (axenic) culture in proteose peptone medium; of the 31 strains which grew normally at room temperature and not at 40°C in that medium, 21 also failed to grow at 37°C. Preliminary results of complementation tests suggest that most, if not all, the mutations are recessive and that a variety of genes was affected. A detailed genetic analysis was performed on one mutant (H9). The results are all consistent with the idea that the heat-sensitive phenotype of this mutant is determined by a single recessive mutation, designated ts-2. Heterozygotes ts-2/+ yield heat-sensitive segregants during vegetative growth; we interpret this finding as another example of allelic exclusion, a phenomenon universally encountered among heterozygotes in syngen 1 of T. pyriformis. Our results are discussed in the context of some questions of current interest in Tetrahymena genetics.

Aspects of Endocytosis in the Ciliate Tetrahymena Pyriformis

1976 ◽  
Vol 34 ◽  
pp. 138-139
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Particulate Matter ◽  
Tetrahymena Pyriformis ◽  
Food Vacuole ◽  
Reference Points ◽  
Nacl Solution ◽  
Latex Particles ◽  
Autophagic Vacuoles ◽  
Bacterial Contaminants ◽  
Cytoplasmic Structures ◽  
Soluble Material

The ciliate, Tetrahymena pyriformis, is an excellent cell for studying endocytic processes. It ingests particulate matter like bacteria and latex particles by way of the buccal apparatus. Soluble material entering by pinocytosis and the coalescing of pinocytic vacuoles to form larger vesicles also occurs. It is not uncommon to see autophagic vacuoles containing recognizable cytoplasmic structures like mitochondria. The visualization of the formation of a food vacuole in the cytopharyngeal region has not been accomplished. Some observations reported in this paper may cast additional light on this and other endocytic processes.Static cultures of log phase cells of strain WH6 were generally used. Most of the preparations studied were of control animals suspended in dilute NaCl solution. Chance bacterial contaminants frequently served as valuable reference points.

scholarly journals Loss of endocytic capacity in aging Paramecium. The importance of cytoplasmic organelles.

1976 ◽  
Vol 71 (2) ◽  
pp. 575-588 ◽  
Author(s):  
J Smith-Sonneborn ◽  
S R Rodermel
Keyword(s):  
Excretion Rate ◽  
Formation Rate ◽  
Food Vacuole ◽  
Cellular Aging ◽  
Critical Importance ◽  
Vacuole Formation ◽  
Cytoplasmic Organelles ◽  
Food Vacuoles ◽  
Excretion Rates

Aged cells have significantly fewer food vacuoles and ingest fewer bacteria than young cells. Loss of food vacuoles was explained by a decreasing difference in the food vacuole formation and excretion rates; the formation rate declined more rapidly than the excretion rate, approaching equivalence at 160 fissions, when the proportion of cells with no food vacuoles, in the presence of excess food, abruptly increased. A model for cellular aging is presented in which control of organelle numbers and cyclical interactions between the nucleus and cytoplasm may be of critical importance.

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