The Basis of Cell-to-cell Transformation in Paramecium Bursaria

1972 ◽  
Vol 11 (2) ◽  
pp. 601-609
Author(s):  
C. A. CULLIS
Keyword(s):  
Thermal Stability ◽  
Mating Type ◽  
Cell Transformation ◽  
Paramecium Bursaria ◽  
Transformed Cells ◽  
Cell Contact ◽  
Mating Types ◽  
Normal Cells ◽  
Type Transformation ◽  
Rna And Dna

A mating type transformation, involving cell-to-cell contact (abortive conjugation) in syngen 4 of Paramecium bursaria has been investigated. By autoradiography, transfer of material between the conjugants in normal and abortive conjugation has been shown to occur. The transfer of this material, which includes protein, RNA and DNA, during abortive conjugation has been shown to be necessary if the transformation is to occur. The mating type substances produced by sexually competent cells of different mating types have been characterized with respect to their thermal stability. In all cases examined there appeared to be 3 mating type substances produced which had different temperature stabilities. No differences could be shown between the transformed cells and normal cells of the same mating type in relation to stability of mating type substance.

The Basis of Cell-to-cell Transformation in Paramecium Bursaria

1972 ◽  
Vol 11 (2) ◽  
pp. 611-619
Author(s):  
C. A. CULLIS
Keyword(s):  
Cell Transformation ◽  
Buoyant Density ◽  
Trisodium Citrate ◽  
Paramecium Bursaria ◽  
Transformed Cells ◽  
Molecular Weights ◽  
Caesium Chloride ◽  
Type Transformation ◽  
Total Dna ◽  
Ionizing Radiations

A mating type transformation occurring in syngen 4 of Paramecium bursaria has been further investigated. The transformation event was not reversed or prevented by acridine or ionizing radiations. The transformation has not been accomplished with cell-free extracts including the microinjection of cytoplasmic extracts. The nucleic acids of normal and transformed cells have been compared. No differences were found. Both types had 2 major ribosomal RNAs of molecular weights 1.29x106 and 0.70x106 Daltons. In both types a particular RNA species, with molecular weight 1.0x105 Daltons, was found only in sexually competent cells. The DNA had a buoyant density in caesium chloride of 1.689 g cm-3 and a Tm in 0.1xSSC (1xSSC=0.15 M sodium chloride, 0.015 M trisodium citrate) of 65.2°C. The renaturation kinetics showed 2 types of DNA - a fast-renaturing component, comprising 13% of the total DNA, with a complexity of 1.84x109 Daltons, and a slow-renaturing component with a complexity of 1.6x1011 Daltons, in both normal and transformed cells. Possible models for the action of the transforming agent are discussed.

scholarly journals Alterations in Cell-Extracellular Matrix Interactions during Progression of Cancers

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Rajeswari Jinka ◽  
Renu Kapoor ◽  
Pavana Goury Sistla ◽  
T. Avinash Raj ◽  
Gopal Pande
Keyword(s):  
Extracellular Matrix ◽  
Cancer Progression ◽  
Cell Transformation ◽  
Tumor Model ◽  
Genetic Alterations ◽  
Model Systems ◽  
Transformed Cells ◽  
Normal Cells ◽  
Multistep Process ◽  
Extracellular Matrix Interactions

Cancer progression is a multistep process during which normal cells exhibit molecular changes that culminate into the highly malignant and metastatic phenotype, observed in cancerous tissues. The initiation of cell transformation is generally associated with genetic alterations in normal cells that lead to the loss of intercellular- and/or extracellular-matrix- (ECM-) mediated cell adhesion. Transformed cells undergo rapid multiplication and generate more modifications in adhesion and motility-related molecules which allow them to escape from the original site and acquire invasive characteristics. Integrins, which are multifunctional adhesion receptors, and are present, on normal as well as transformed cells, assist the cells undergoing tumor progression in creating the appropriate environment for their survival, growth, and invasion. In this paper, we have briefly discussed the role of ECM proteins and integrins during cancer progression and described some unique conditions where adhesion-related changes could induce genetic mutations in anchorage-independent tumor model systems.

scholarly journals The mating-type substances of Paramecium bursaria

1963 ◽  
Vol 4 (1) ◽  
pp. 143-150 ◽  
Author(s):  
L. W. Cohen ◽  
R. W. Siegel
Keyword(s):  
Mating Type ◽  
Lateral Surface ◽  
Paramecium Bursaria ◽  
Heat Inactivation ◽  
Mating Types ◽  
Unique Combination ◽  
Heat Labile ◽  
Sexually Reactive

The detached cilia from sexually reactive cells of Paramecium bursaria will agglutinate with the cilia of intact sexually reactive animals of a complementary mating type. No such reaction will occur if incompetent cells are used or if the cells are of the same mating type. Particulates other than cilia do not adhere to tester cells; the cilia which carry the specific mating-type substances are restricted to the ventro-lateral surface of the animal.Studies of the heat inactivation of the ability of detached cilia to agglutinate confirm in detail the hypothesis of Metz which holds that cell unions leading to conjugation are brought about by the interaction of two pairs of complementary substances, A and a and B and b; the former pair of substances is more heat labile than the latter. The data suggest that animals of each of the four mating types carry a unique combination of two substances, namely, AB, aB, ab, and Ab.

Differences in Membrane Order between C 3 H 10 T1/2 Cells and Their Transformed Counterparts as Measured by EPR

1992 ◽  
Vol 47 (1-2) ◽  
pp. 148-154 ◽  
Author(s):  
G. F. Grossi ◽  
M. Durante ◽  
M. Napolitano ◽  
A. Lanzone ◽  
P. Riccardi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Hyperfine Splitting ◽  
Cell Transformation ◽  
Lipid Analysis ◽  
Cell Types ◽  
Transformed Cells ◽  
Fatty Acids Composition ◽  
Normal Cells ◽  
Membrane Order ◽  
Mouse Embryo Fibroblasts

Abstract Membrane order of mouse embryo fibroblasts and their ionizing radiation and chemically transformed counterparts was investigated using EPR spectroscopy after labeling the membrane of the cells with the fatty acid spin label, 5-nitroxy stearic acid. The EPR spectra were recorded at temperatures ranging from 18 to 38 °C for both control and transformed cells. The distance between the outer hyperfine splitting (2 T′||), which is used as an indicator of membrane order, varies in these two cell types. Below 28 °C, 2T′II is higher in transformed fibroblasts than in normal cells, whereas above this temperature membrane order is the same. Lipid analysis as carried out by the measurement of the cholesterol/membrane proteins and sphingomyelin/lecithin ratios, showed no difference in the amounts of the main membrane rigidifiers. These findings suggest that cell transformation of mouse fibroblasts induced by radiation or chemicals may produce alterations in the cell membrane, as evidenced by variations in its order at low temperature. These measured differences are presumably not attributable to its fatty acids composition but to its glycoproteins content, since changes in membrane regidifiers were not observed between normal and transformed cells.

scholarly journals Differential Gene Expression between Fungal Mating Types Is Associated with Sequence Degeneration

2020 ◽  
Vol 12 (4) ◽  
pp. 243-258 ◽  
Author(s):  
Wen-Juan Ma ◽  
Fantin Carpentier ◽  
Tatiana Giraud ◽  
Michael E Hood
Keyword(s):  
Differential Expression ◽  
Differentially Expressed Genes ◽  
Mating Type ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Gc Content ◽  
Differentially Expressed ◽  
Mating Types ◽  
Sexual Antagonism ◽  
Recombination Suppression

Abstract Degenerative mutations in non-recombining regions, such as in sex chromosomes, may lead to differential expression between alleles if mutations occur stochastically in one or the other allele. Reduced allelic expression due to degeneration has indeed been suggested to occur in various sex-chromosome systems. However, whether an association occurs between specific signatures of degeneration and differential expression between alleles has not been extensively tested, and sexual antagonism can also cause differential expression on sex chromosomes. The anther-smut fungus Microbotryum lychnidis-dioicae is ideal for testing associations between specific degenerative signatures and differential expression because 1) there are multiple evolutionary strata on the mating-type chromosomes, reflecting successive recombination suppression linked to mating-type loci; 2) separate haploid cultures of opposite mating types help identify differential expression between alleles; and 3) there is no sexual antagonism as a confounding factor accounting for differential expression. We found that differentially expressed genes were enriched in the four oldest evolutionary strata compared with other genomic compartments, and that, within compartments, several signatures of sequence degeneration were greater for differentially expressed than non-differentially expressed genes. Two particular degenerative signatures were significantly associated with lower expression levels within differentially expressed allele pairs: upstream insertion of transposable elements and mutations truncating the protein length. Other degenerative mutations associated with differential expression included nonsynonymous substitutions and altered intron or GC content. The association between differential expression and allele degeneration is relevant for a broad range of taxa where mating compatibility or sex is determined by genes located in large regions where recombination is suppressed.

scholarly journals Deletion of the Schizophyllum commune Aα Locus: The Roles of Aα Y and Z Mating-Type Genes

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1437-1444
Author(s):  
C Ian Robertson ◽  
Kirk A Bartholomew ◽  
Charles P Novotny ◽  
Robert C Ullrich
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Mating Types ◽  
Developmental Pathway ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Regulatory Loci ◽  
Type Gene

The Aα locus is one of four master regulatory loci that determine mating type and regulate sexual development in Schizophyllum commune. We have made a plasmid containing a URA1 gene disruption of the Aα Y1 gene. Y1 is the sole Aα gene in Aα1 strains. We used the plasmid construction to produce an Aα null (i.e., AαΔ) strain by replacing the genomic Y1 gene with URA1 in an Aα1 strain. To characterize the role of the Aα genes in the regulation of sexual development, we transformed various Aα Y and Z alleles into AαΔ strains and examined the acquired mating types and mating abilities of the transformants. These experiments demonstrate that the Aα Y gene is not essential for fungal viability and growth, that a solitary Z Aα mating-type gene does not itself activate development, that Aβ proteins are sufficient to activate the A developmental pathway in the absence of Aα proteins and confirm that Y and Z genes are the sole determinants of Aα mating type. The data from these experiments support and refine our model of the regulation of A-pathway events by Y and Z proteins.

scholarly journals A PCR-based Assay for Distinguishing between A1 and A2 Mating Types of Phytophthora capsici

2017 ◽  
Vol 142 (4) ◽  
pp. 260-264
Author(s):  
Ping Li ◽  
Dong Liu ◽  
Min Guo ◽  
Yuemin Pan ◽  
Fangxin Chen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mating Type ◽  
Phytophthora Capsici ◽  
Mating Types ◽  
Sequence Repeat ◽  
Chain Reaction ◽  
Plant Parasite ◽  
Dna Fragment ◽  
Polymerase Chain ◽  
Microsatellite Diversity

Sexual reproduction in the plant parasite Phytophthora capsici Leonian requires the interaction of two distinct mating types, A1 and A2. Co-occurrence of these mating types can enhance the genetic diversity of P. capsici and alter its virulence or resistance characteristics. Using an intersimple sequence repeat (ISSR) screen of microsatellite diversity, we identified, cloned, and sequenced a novel 1121-base pair (bp) fragment specific to the A1 mating type of P. capsici. Primers Pcap-1 and Pcap-2 were designed from this DNA fragment to specifically detect the A1 mating type. Polymerase chain reaction (PCR) using these primers amplified an expected 997-bp fragment from known A1 mating types, but yielded a 508-bp fragment from known A2 mating types. This PCR-based assay could be adapted to accurately and rapidly detect the co-occurrence of A1 and A2 P. capsici mating types from field material.

The alpha-mating type locus of Cryptococcus neoformans contains a peptide pheromone gene

1993 ◽  
Vol 13 (3) ◽  
pp. 1962-1970
Author(s):  
T D Moore ◽  
J C Edman
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Cell Types ◽  
Yeast Cells ◽  
Mating Types ◽  
Type Locus ◽  
Reading Frame ◽  
Cloning Method ◽  
Opportunistic Fungal Pathogen ◽  
Specific Fragment

The opportunistic fungal pathogen Cryptococcus neoformans has two mating types, MATa and MAT alpha. The MAT alpha strains are more virulent. Mating of opposite mating type haploid yeast cells results in the production of a filamentous hyphal phase. The MAT alpha locus has been isolated in this study in order to identify the genetic differences between mating types and their contribution to virulence. A 138-bp fragment of MAT alpha-specific DNA which cosegregates with alpha-mating type was isolated by using a difference cloning method. Overlapping phage and cosmid clones spanning the entire MAT alpha locus were isolated by using this MAT alpha-specific fragment as a probe. Mapping of these clones physically defined the MAT alpha locus to a 35- to 45-kb region which is present only in MAT alpha strains. Transformation studies with fragments of the MAT alpha locus identified a 2.1-kb XbaI-HindIII fragment that directs starvation-induced filament formation in MATa cells but not in MAT alpha cells. This 2.1-kb fragment contains a gene, MF alpha, with a small open reading frame encoding a pheromone precursor similar to the lipoprotein mating factors found in Saccharomyces cerevisiae, Ustilago maydis, and Schizosaccharomyces pombe. The ability of the MATa cells to express, process, and secrete the MAT alpha pheromone in response to starvation suggests similar mechanisms for these processes in both cell types. These results also suggest that the production of pheromone is under a type of nutritional control shared by the two cell types.

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