DNA from Isolated Pellicles of Tetrahymena

1971 ◽  
Vol 9 (3) ◽  
pp. 719-726
Author(s):  
R. A. FLAVELL ◽  
I. G. JONES
Keyword(s):  
Mitochondrial Dna ◽  
High Speed ◽  
Nuclear Dna ◽  
Tetrahymena Pyriformis ◽  
Heavy Component ◽  
Cscl Gradient ◽  
Mitochondria Dna ◽  
Similar Enrichment

Large pellicle fragments were isolated from Tetrahymena pyriformis, strain T, by 2 procedures: homogenization after treatment with 40% ethanol at -20 °C, or direct homogenization in a sucrose-EDTA buffer. All preparations contained entrapped mitochondria. DNA prepared from these pellicles was analysed on a CsCl gradient, and contained 3 components of buoyant densities 1.685, 1.688, and 1.698 g cm-3 in variable proportions. The component at 1.685 g cm-3 is similar in density to mitochondrial DNA and those at 1.688 and 1.698g cm-3 to components of nuclear DNA. Most pellicle preparations contained a higher proportion of the heavy component (1.698 g cm-3) than does nuclear DNA. A similar enrichment of this component could be demonstrated in high-speed pellets from fragmented nuclei. No unique pellicle-associated component could be demonstrated. No DNA could be isolated from very pure preparations of oral plates and we conclude that there is no evidence for the presence of a specific DNA associated with the pellicle.

scholarly journals THE DISTRIBUTION OF DNA AMONG DIVIDING MITOCHONDRIA OF TETRAHYMENA PYRIFORMIS

1968 ◽  
Vol 37 (3) ◽  
pp. 683-693 ◽  
Author(s):  
John A. Parsons ◽  
Ronald C. Rustad
Keyword(s):  
Mitochondrial Dna ◽  
Dna Synthesis ◽  
Genetic Information ◽  
Nuclear Dna ◽  
De Novo ◽  
Genetic Material ◽  
Tetrahymena Pyriformis ◽  
Population Doubling ◽  
Population Doubling Time ◽  
The Stability

A squash technique was developed for log phase Tetrahymena pyriformis which permitted the resolution of over 100 individual mitochondria from a single cell. Mitochondria incorporated thymidine at all stages of the cell cycle, even when nuclear DNA synthesis was not occurring. During the stage of macronuclear DNA synthesis, however, there was a significant increase in the extent of mitochondrial labeling. Low radioautograph background suggests that mitochondrial DNA is synthesized at the mitochondria themselves. All mitochondria incorporated thymidine-3H within one population-doubling time. Grain counts also showed that the amount of mitochondrial label was retained for four generations and that this label remained randomly distributed among all mitochondria during this time. The results are not consistent with any theory of de-novo or "microbody" origin of mitochondria, but do support the hypothesis that mitochondria are produced by the growth and division of preexisting mitochondria. The stability of the mitochondrial DNA and its distribution among daughter mitochondria satisfy two prerequisites for a genetic material. The possibility is discussed that some of the genetic information for the mitochondrion is contained in the DNA associated with this organelle.

scholarly journals Plasma derived cell-free mitochondrial DNA originates mainly from circulating cell-free mitochondria

2021 ◽  
Author(s):  
Benoit Roch ◽  
Ekaterina Pisareva ◽  
Cynthia Sanchez ◽  
Brice Pastor ◽  
Rita Tanos ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Extracellular Vesicles ◽  
High Speed ◽  
Nuclear Dna ◽  
Protein Complexes ◽  
Structural Features ◽  
Differential Centrifugation ◽  
Analytical Strategy ◽  
Low Pass ◽  
Physical Examinations

Circulating mitochondrial DNA (cir-mtDNA) could have a potential comparable to circulating nuclear DNA (cir-nDNA), with numerous applications. However, research and development in this area have fallen behind, particularly considering its origin and structural features. To tackle this, we initially combined Q-PCR and low-pass whole genome sequencing in the same analytical strategy previously and successfully used for cir-nDNA. This revealed unexplained structural patterns and led us to correlate these data with observations made during physical examinations such as filtration, and differential centrifugation in various plasma preparations. Both the integrity index and number of reads revealed a very minor proportion of low size-ranged fragments (<1000 bp) in plasma obtained with a standard preparation (0.06%). Filtration and high speed second step centrifugation revealed that 98.7 and 99.4% corresponded to extracellular mitochondria either free or in large extracellular vesicles. When avoiding platelet activation during plasma preparation, the proportion of both types of entities was still preponderant (76-80%), but the amount of detected mitochondrial DNA decreased 67-fold. In correlation with our previous study on the presence of circulating cell-free mitochondria in blood, our differential centrifugation procedure suggested that cir-mtDNA is also associated with approximately 18% small extracellular vesicles, 1.7% exosomes and 4% protein complexes.

scholarly journals Mitochondrial deoxyribonucleic acid from Tetrahymena pyriformis and its kinetic complexity

1970 ◽  
Vol 116 (5) ◽  
pp. 811-817 ◽  
Author(s):  
R. A. Flavell ◽  
I. G. Jones
Keyword(s):  
Mitochondrial Dna ◽  
Melting Temperature ◽  
Density Gradient ◽  
Deoxyribonucleic Acid ◽  
Nuclear Dna ◽  
Buoyant Density ◽  
Tetrahymena Pyriformis ◽  
Base Pairing ◽  
Caesium Chloride ◽  
Kinetics Of

1. Mitochondrial DNA from Tetrahymena pyriformis strain T has a buoyant density (ρ) of 1.685 compared with ρ1.688 for whole cell DNA. Mitochondrial preparations from T. pyriformis strain W show an enrichment of a light satellite (ρ1.686), although this is not obtained free from nuclear DNA (ρ1.692). 2. T. pyriformis mitochondrial DNA renatures rapidly and the kinetics of this process indicate a complexity of approx. 3×107 daltons. 3. The base-pairing in the renaturation product is of a precise nature, since the ‘melting’ temperature (80.5°C) is indistinguishable from that of the native DNA (80.5°C). 4. Centrifugation of mitochondrial DNA in an alkaline caesium chloride density gradient gives two bands, implying the separation of the complementary strands.

scholarly journals The Role of Mitochondria in Carcinogenesis

2021 ◽  
Vol 22 (10) ◽  
pp. 5100
Author(s):  
Paulina Kozakiewicz ◽  
Ludmiła Grzybowska-Szatkowska ◽  
Marzanna Ciesielka ◽  
Jolanta Rzymowska
Keyword(s):  
Prostate Cancer ◽  
Mitochondrial Dna ◽  
Nuclear Dna ◽  
Dna Polymorphisms ◽  
Gene Encoding ◽  
Dna Mutations ◽  
Nadh Ubiquinone Oxidoreductase ◽  
Gene Coi ◽  
The Impact

The mitochondria are essential for normal cell functioning. Changes in mitochondrial DNA (mtDNA) may affect the occurrence of some chronic diseases and cancer. This process is complex and not entirely understood. The assignment to a particular mitochondrial haplogroup may be a factor that either contributes to cancer development or reduces its likelihood. Mutations in mtDNA occurring via an increase in reactive oxygen species may favour the occurrence of further changes both in mitochondrial and nuclear DNA. Mitochondrial DNA mutations in postmitotic cells are not inherited, but may play a role both in initiation and progression of cancer. One of the first discovered polymorphisms associated with cancer was in the gene NADH-ubiquinone oxidoreductase chain 3 (mt-ND3) and it was typical of haplogroup N. In prostate cancer, these mutations and polymorphisms involve a gene encoding subunit I of respiratory complex IV cytochrome c oxidase subunit 1 gene (COI). At present, a growing number of studies also address the impact of mtDNA polymorphisms on prognosis in cancer patients. Some of the mitochondrial DNA polymorphisms occur in both chronic disease and cancer, for instance polymorphism G5913A characteristic of prostate cancer and hypertension.

Evidence for genetic hybridization between Ixodes scapularis and Ixodes cookei

2017 ◽  
Vol 95 (8) ◽  
pp. 527-537 ◽  
Author(s):  
James W. Patterson ◽  
Anna M. Duncan ◽  
Kelsey C. McIntyre ◽  
Vett K. Lloyd
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Analysis ◽  
New Brunswick ◽  
Nuclear Dna ◽  
Ixodes Scapularis ◽  
Companion Animals ◽  
Genetic Introgression ◽  
Eastern Canada ◽  
As Species ◽  
Intermediate Traits

Ixodes scapularis Say, 1821 (the black-legged tick) is becoming established in Canada. The northwards expansion of I. scapularis leads to contact between I. scapularis and Ixodes cookei Packard, 1869, a well-established tick species in Eastern Canada. Examination of I. cookei and I. scapularis collected from New Brunswick revealed ticks with ambiguous morphologies, with either a mixture or intermediate traits typical of I. scapularis and I. cookei, including in characteristics typically used as species identifiers. Genetic analysis to determine if these ticks represent hybrids revealed that four had I. cookei derived mitochondrial DNA but I. scapularis nuclear DNA. In one case, the nuclear sequence showed evidence of heterozygosity for I. scapularis and I. cookei sequences, whereas in the others, the nuclear DNA appeared to be entirely derived from I. scapularis. These data strongly suggest genetic hybridization between these two species. Ixodes cookei and hybrid ticks were readily collected from humans and companion animals and specimens infected with Borrelia burgdorferi Johnson et al., 1984, the causative agent of Lyme disease, were identified. These findings raise the issue of genetic introgression of I. scapularis genes into I. cookei and warrant reassessment of the capacity of I. cookei and I. cookei × I. scapularis hybrids to vector Borrelia infection.

scholarly journals Mitochondrial DNA Heteroplasmy as an Informational Reservoir Dynamically Linked to Metabolic and Immunological Processes Associated with COVID-19 Neurological Disorders

2021 ◽  
Author(s):  
George B. Stefano ◽  
Richard M. Kream
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Function ◽  
Neurological Disorders ◽  
Nuclear Dna ◽  
Mitochondrial Dynamics ◽  
Cell Types ◽  
Tissue Specific ◽  
Copy Numbers ◽  
The Central Nervous System ◽  
Mitochondrial Dna Heteroplasmy

AbstractMitochondrial DNA (mtDNA) heteroplasmy is the dynamically determined co-expression of wild type (WT) inherited polymorphisms and collective time-dependent somatic mutations within individual mtDNA genomes. The temporal expression and distribution of cell-specific and tissue-specific mtDNA heteroplasmy in healthy individuals may be functionally associated with intracellular mitochondrial signaling pathways and nuclear DNA gene expression. The maintenance of endogenously regulated tissue-specific copy numbers of heteroplasmic mtDNA may represent a sensitive biomarker of homeostasis of mitochondrial dynamics, metabolic integrity, and immune competence. Myeloid cells, monocytes, macrophages, and antigen-presenting dendritic cells undergo programmed changes in mitochondrial metabolism according to innate and adaptive immunological processes. In the central nervous system (CNS), the polarization of activated microglial cells is dependent on strategically programmed changes in mitochondrial function. Therefore, variations in heteroplasmic mtDNA copy numbers may have functional consequences in metabolically competent mitochondria in innate and adaptive immune processes involving the CNS. Recently, altered mitochondrial function has been demonstrated in the progression of coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Accordingly, our review is organized to present convergent lines of empirical evidence that potentially link expression of mtDNA heteroplasmy by functionally interactive CNS cell types to the extent and severity of acute and chronic post-COVID-19 neurological disorders.

scholarly journals Mitochondrial DNA Methylation and Human Diseases

2021 ◽  
Vol 22 (9) ◽  
pp. 4594
Author(s):  
Andrea Stoccoro ◽  
Fabio Coppedè
Keyword(s):  
Dna Methylation ◽  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Nuclear Dna ◽  
Epigenetic Modification ◽  
Nuclear Genome ◽  
Epigenetic Modifications ◽  
Human Diseases ◽  
Loop Region ◽  
D Loop

Epigenetic modifications of the nuclear genome, including DNA methylation, histone modifications and non-coding RNA post-transcriptional regulation, are increasingly being involved in the pathogenesis of several human diseases. Recent evidence suggests that also epigenetic modifications of the mitochondrial genome could contribute to the etiology of human diseases. In particular, altered methylation and hydroxymethylation levels of mitochondrial DNA (mtDNA) have been found in animal models and in human tissues from patients affected by cancer, obesity, diabetes and cardiovascular and neurodegenerative diseases. Moreover, environmental factors, as well as nuclear DNA genetic variants, have been found to impair mtDNA methylation patterns. Some authors failed to find DNA methylation marks in the mitochondrial genome, suggesting that it is unlikely that this epigenetic modification plays any role in the control of the mitochondrial function. On the other hand, several other studies successfully identified the presence of mtDNA methylation, particularly in the mitochondrial displacement loop (D-loop) region, relating it to changes in both mtDNA gene transcription and mitochondrial replication. Overall, investigations performed until now suggest that methylation and hydroxymethylation marks are present in the mtDNA genome, albeit at lower levels compared to those detectable in nuclear DNA, potentially contributing to the mitochondria impairment underlying several human diseases.

Mitochondrial and nuclear DNA variation, genotype fingerprinting and genetic relationships in lentil (Lens culinaris Medik.)

1997 ◽  
Vol 77 (4) ◽  
pp. 515-521 ◽  
Author(s):  
Om P. Rajora ◽  
John D. Mahon
Keyword(s):  
Mitochondrial Dna ◽  
Restriction Fragment ◽  
Lens Culinaris ◽  
Nuclear Dna ◽  
Genetic Relationships ◽  
Restriction Enzymes ◽  
Dna Variation ◽  
Apocytochrome B ◽  
Nuclear Dna Variation ◽  
Mean Similarity

Mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) variations were examined in six cultivars of Lens culinaris ssp. culinaris and two (mtDNA) or one (nuDNA) accession(s) of L. culinaris ssp. orientalis. Total leaf DNA was digested with up to 15 restriction endonucleases, separated by agarose gel electrophoresis and trasferred to nylon membranes. To examine mtDNA variation, blots were probed with mtDNA coding for cytochrome c oxidase I (coxI) and ATPase 6 (atp6) of both wheat and maize as well as apocytochrome b (cob) and Orf25 (orf25) of wheat. Sixteen combinations of mtDNA probes and restriction enzymes revealed 34 fragments that discriminated between at least two lentil accessions. For nuDNA analysis, probes from cDNA and genomic DNA clones of lentil were used to probe the same blots, and identified 46 diagnostic fragments from 19 probe/enzyme combinations. Each lentil accession could be unequivocably distinguished from all others on the basis of both mitochondrial and nuclear DNA fragment patterns. The mitochondrial restriction fragment similarities ranged from 0.944 to 0.989, with a mean of 0.970 but nuclear restriction fragment similarities varied from 0.582 to 0.987, with a mean of 0.743. The apparent genetic relationships among accessions differed according to the source of DNA examined, although the commercial varieties Laird, Brewer and Redchief showed similarly high levels of mean similarity with both nuclear (0.982) and mitochondrial DNA (0.983). Key words: Lens culinaris Medik., genetic variation, mitochondrial, nuclear, DNA, lentil

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