scholarly journals Role for Endocytosis in Conjugation in Tetrahymena

1982 ◽  
Vol 2 (6) ◽  
pp. 633-637
Author(s):  
Minna B. Rotheim ◽  
Bruce Love
Keyword(s):  
Tetrahymena Thermophila ◽  
Pair Formation ◽  
Cell Contact ◽  
Mating Types ◽  
Cell Pair ◽  
Receptor Mediated Endocytosis ◽  
Cellular Components ◽  
Effect Of Inhibitors

We examined the effect of inhibitors of receptor-mediated endocytosis on cell pair formation during conjugation in Tetrahymena thermophila. Dansylcadaverine (20 μM), methylamine (20 mM), and bacitracin (2 mg/ml) prevented cell pair formation even when added poststarvation, after mixing of cells of opposite mating types (during the prepairing interaction). Chloroquine (10 and 25 μM) did not inhibit cell pair formation, leading to the conclusion that inhibition by dansylcadaverine, methylamine, and bacitracin is not due to an alkalinization of the lysosome. These results did not allow us to define the time in the prepairing interaction at which inhibition occurs, nor to identify the cellular components involved, but they did support the hypothesis that an endocytotic event(s) plays a role in the cell contact-mediated recognition which occurs during the prepairing interaction.

scholarly journals Role for Endocytosis in Conjugation inTetrahymena

1982 ◽  
Vol 2 (6) ◽  
pp. 633-637 ◽  
Author(s):  
Minna B. Rotheim ◽  
Bruce Love
Keyword(s):  
Tetrahymena Thermophila ◽  
Pair Formation ◽  
Cell Contact ◽  
Mating Types ◽  
Cell Pair ◽  
Receptor Mediated Endocytosis ◽  
Cellular Components ◽  
Effect Of Inhibitors

We examined the effect of inhibitors of receptor-mediated endocytosis on cell pair formation during conjugation inTetrahymena thermophila.Dansylcadaverine (20 μM), methylamine (20 mM), and bacitracin (2 mg/ml) prevented cell pair formation even when added poststarvation, after mixing of cells of opposite mating types (during the prepairing interaction). Chloroquine (10 and 25 μM) did not inhibit cell pair formation, leading to the conclusion that inhibition by dansylcadaverine, methylamine, and bacitracin is not due to an alkalinization of the lysosome. These results did not allow us to define the time in the prepairing interaction at which inhibition occurs, nor to identify the cellular components involved, but they did support the hypothesis that an endocytotic event(s) plays a role in the cell contact-mediated recognition which occurs during the prepairing interaction.

scholarly journals Homotypic pair formation during conjugation in Tetrahymena thermophila

1986 ◽  
Vol 82 (1) ◽  
pp. 223-234
Author(s):  
A. Kitamura ◽  
T. Sugai ◽  
Y. Kitamura
Keyword(s):  
Phospholipase C ◽  
Mating Type ◽  
Tetrahymena Thermophila ◽  
Single Cells ◽  
Initial Step ◽  
Pair Formation ◽  
Mating Types ◽  
Morphological Markers ◽  
Mechanical Separation

In the ciliate Tetrahymena thermophila, conjugation has been believed to occur only between cells of different mating types. We found the formation of homotypic pairs during normal conjugation by using micronuclear morphological markers. Homotypic pairs formed preferentially during the first 10 min following the first pair formation and comprised about half of the pairs. These results suggest the involvement of mating-type non-specific adhesion of cells in the initial step of conjugation. Homotypic pairs apparently persist for at least 30 min and then separate into single cells. Homotypic pairs are also formed when conjugant pairs re-form after mechanical separation of heterotypic pairs. Five kinds of glycosidases, three kinds of proteases and phospholipase C showed no effect on either the formation of homotypic pairs of their separation. The relation between the mating-type substances and the molecules responsible for mating-type non-specific adhesion of cells is discussed.

Induction of cybrid strains of Tetrahymena thermophila by electrofusion

1988 ◽  
Vol 89 (2) ◽  
pp. 253-261
Author(s):  
J. Gaertig ◽  
M. Kiersnowska ◽  
F. Iftode
Keyword(s):  
Tetrahymena Thermophila ◽  
Mating Types ◽  
Drug Resistant ◽  
Ciliated Protozoan ◽  
Chloramphenicol Resistance ◽  
Electric Pulses ◽  
Conductive Medium ◽  
Membrane Contact ◽  
Initial Process ◽  
Partial Integration

In this paper, the electrofusion of the ciliated protozoan, Tetrahymena thermophila, is described. Deciliated cells were brought into close membrane contact by dielectrophoresis in a weakly conductive medium. Then cell fusion was induced by application of repeated electric pulses. Up to 20 prestarved, logarithmic or stationary phase cells of the same or different mating types may form a single giant cell. The polykaryons are fully able to regenerate cilia and became motile. After an initial process of partial integration the polykaryons yield viable clones by separation of components. Cytoplasmic exchange between fused components occurs before separation. Cytoplasmically inherited chloramphenicol resistance was transmitted from one strain to another by electrofusion and drug-resistant cybrid strains were generated.

scholarly journals GENES CONTROLLING MATING-TYPE SPECIFICITY IN PARAMECIUM CAUDATUM: THREE LOCI REVEALED BY INTERSYNGENIC CROSSES

Genetics ◽  
1983 ◽  
Vol 104 (1) ◽  
pp. 41-62
Author(s):  
Yuuji Tsukii ◽  
Koichi Hiwatashi
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Pair Formation ◽  
High Fertility ◽  
Mating Types ◽  
Paramecium Caudatum ◽  
Multiple Alleles ◽  
Behavioral Marker ◽  
Species Pairs ◽  
Recessive Homozygote

ABSTRACT In mating interactions in Paramecium caudatum, initial mating agglutination is strictly mating-type specific, but subsequent conjugating pair formation is not mating-type specific. Using this nonspecificity of pair formation, intersyngenic (intersibling species) pairs were induced by mixing four mating types of two different syngens. To distinguish intersyngenic pairs from intrasyngenic ones, the behavioral marker CNR (Takahashi 1979) was mainly used. Clones of intersyngenic hybrids showed high fertility and thus made feasible a genetic analysis of syngenic specificity of mating type. The syngenic specificities of E (even) mating types were found to be controlled by co-dominant multiple alleles at the Mt locus, and those of O (odd) mating types by interactions of co-dominant multiple alleles at two loci, MA and MB. Clones of heterozygotes express dual mating types. Mt is epistatic to MA and MB, and thus O mating types can be expressed only in the recessive homozygote (mt/mt) at the Mt locus. In addition, at least one allele each at the MA and MB loci must have a common syngen specificity for the expression of O types. Thus, when MA is homozygous for one syngen and MB is homozygous for another syngen, no mating type is expressed.

scholarly journals Selecting One of Several Mating Types through Gene Segment Joining and Deletion in Tetrahymena thermophila

PLoS Biology ◽  
2013 ◽  
Vol 11 (3) ◽  
pp. e1001518 ◽  
Author(s):  
Marcella D. Cervantes ◽  
Eileen P. Hamilton ◽  
Jie Xiong ◽  
Michael J. Lawson ◽  
Dongxia Yuan ◽  
...  
Keyword(s):  
Tetrahymena Thermophila ◽  
Gene Segment ◽  
Mating Types

scholarly journals Correction: Selecting One of Several Mating Types through Gene Segment Joining and Deletion in Tetrahymena thermophila

PLoS Biology ◽  
2015 ◽  
Vol 13 (10) ◽  
pp. e1002284 ◽  
Author(s):  
Marcella D. Cervantes ◽  
Eileen P. Hamilton ◽  
Jie Xiong ◽  
Michael J. Lawson ◽  
Dongxia Yuan ◽  
...  
Keyword(s):  
Tetrahymena Thermophila ◽  
Gene Segment ◽  
Mating Types

scholarly journals Regulated secretion of a serine protease that activates an extracellular matrix-degrading metalloprotease during fertilization in Chlamydomonas.

1989 ◽  
Vol 109 (4) ◽  
pp. 1689-1694 ◽  
Author(s):  
W J Snell ◽  
W A Eskue ◽  
M J Buchanan
Keyword(s):  
Extracellular Matrix ◽  
Cell Wall ◽  
Serine Protease ◽  
Cellular Responses ◽  
Cell Contact ◽  
Relative Molecular Mass ◽  
Mating Types ◽  
Dibutyryl Camp ◽  
Sexual Signal ◽  
Regulated Secretion

During fertilization in the biflagellated alga, Chlamydomonas reinhardtii, gametes of opposite mating types adhere to each other via agglutinin molecules located on their flagellar surfaces, generating a sexual signal that induces several cellular responses including cell wall release. This cell contact-generated signal is mediated by cAMP and release of the wall, which is devoid of cellulose and contains several hydroxyproline-rich glycoproteins, is due to the activation of a metalloprotease, lysin. Although we originally assumed that lysin would be stored intracellularly in a compartment structurally separate from its substrate, recently we showed that lysin is stored in the periplasm as an inactive, higher relative molecular mass precursor, prolysin (Buchanan, M.J., S. H. Imam, W. A. Eskue, and W. J. Snell. 1989. J. Cell Biol. 108:199-207). Here we show that conversion of prolysin to lysin is due to a cellular, nonperiplasmic enzyme that has the properties of a serine protease. Release of this serine protease into the periplasm is induced by incubation of gametes in dibutyryl cAMP. This may be one of the few examples of regulated secretion of a protease in a eucaryotic microorganism and a novel example of regulated secretion in a plant system.

Effects of Virus Size and Cell Stiffness on Forces, Work, and Pressures Driving Membrane Invagination in a Receptor-Mediated Endocytosis

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Amit Gefen
Keyword(s):  
Elastic Modulus ◽  
Host Cell ◽  
Early Stage ◽  
Cell Stiffness ◽  
Cell Contact ◽  
Nanodrug Delivery ◽  
Receptor Mediated Endocytosis ◽  
Membrane Invagination ◽  
Virus Size ◽  
Contact Pressures

A continuum model based on the contact mechanics theory was developed and used for evaluating virus indentation forces at the early stage of membrane invagination, as well as the work of the virus indentation forces and virus-cell contact pressures in a receptor-mediated endocytosis, depending on the virus size and virus/cell stiffnesses. The model indicated that early virus indentation forces are in the order of 1–10 pN and for a given extent of virus engulfment, they increase linearly with the elastic modulus of the host cell and also with the square of the virus radius. The work of invagination at the initial phase of virus endocytosis is in the order of tens of zeptojoules and peak virus-cell contact pressures at this stage are in the order of hundreds of Pascals to several kPa. For a given extent of virus engulfment, peak and average contact pressures increase linearly with the elastic modulus of the host cell but interestingly, they are negligibly affected by the virus size. The present model may be useful in the fields of cellular biomechanics, virology and nanodrug delivery to evaluate mechanical factors during the early phase of membrane invagination.

scholarly journals Structural coupling of cardiomyocytes and noncardiomyocytes: quantitative comparisons using a novel micropatterned cell pair assay

2008 ◽  
Vol 295 (1) ◽  
pp. H390-H400 ◽  
Author(s):  
Dawn M. Pedrotty ◽  
Rebecca Y. Klinger ◽  
Nima Badie ◽  
Sara Hinds ◽  
Ara Kardashian ◽  
...  
Keyword(s):  
Cardiac Fibroblasts ◽  
Cell Contact ◽  
Cellular Interactions ◽  
Vitro Assay ◽  
Cell Therapies ◽  
Cell Pair ◽  
Skeletal Myoblasts ◽  
Further Development ◽  
Cell Cell

Well-controlled studies of the structural and functional interactions between cardiomyocytes and other cells are essential for understanding heart pathophysiology and for the further development of safe and efficient cell therapies. We established a novel in vitro assay composed of a large number of individual micropatterned cell pairs with reproducible shape, size, and region of cell-cell contact. This assay was applied to quantify and compare the frequency of expression and distribution of electrical (connexin43) and mechanical (N-cadherin) coupling proteins in 5,000 cell pairs made of cardiomyocytes (CMs), cardiac fibroblasts (CFs), skeletal myoblasts (SKMs), and mesenchymal stem cells (MSCs). We found that for all cell pair types, side-side contacts between two cells formed 4.5–14.3 times more often than end-end contacts. Both connexin43 and N-cadherin were expressed in all homotypic CM pairs but in only 13.4–91.6% of pairs containing noncardiomyocytes, where expression was either junctional (at the site of cell-cell contact) or diffuse (inside the cytoplasm). CM expression was exclusively junctional in homotypic pairs but predominantly diffuse in heterotypic pairs. Noncardiomyocyte homotypic pairs exhibited diffuse expression 1.7–8.7 times more often than junctional expression, which was increased 2.6–4.4 times in heterotypic pairs. Junctional connexin43 and N-cadherin expression, respectively, were found in 38.6 ± 7.3 and 39.6 ± 6.2% of CM-MSC pairs, 21.9 ± 5.0 and 13.6 ± 1.9% of CM-SKM pairs, and in only 3.8–9.6% of CM-CF pairs. Measured frequencies of protein expression and distribution were stable for at least 4 days. Described studies in micropatterned cell pairs shed new light on cellular interactions relevant for cardiac function and cell therapies.

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