Homology of Agaricus mitochondrial plasmids with mitochondrial DNA

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 710-716 ◽  
Author(s):  
Robert J. Meyer ◽  
William A. Hintz ◽  
Madan Mohan ◽  
Mary Robison ◽  
James B. Anderson ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Agaricus Bisporus ◽  
Restriction Maps ◽  
Linear Plasmids ◽  
Homologous Sequences ◽  
Hybridization Probes ◽  
Extrachromosomal Element ◽  
Agaricus Bitorquis ◽  
Bacterial Plasmid

A strain of Agaricus bitorquis (Ag4) contains two linear plasmids, pEM and pMPJ. Restriction maps for these two plasmids were determined. Similar plasmid-like DNAs were found to be present in some other strains of A. bitorquis but none were found in strains of the commercial mushroom Agaricus bisporus. The three internal EcoRI fragments of pEM were cloned into a bacterial plasmid and were subsequently used as hybridization probes. The cloned portion of pEM has homology with sequences present in the mitochondrial genome of strains of A. bisporus and A. bitorquis, even those without pEM or any obvious extrachromosomal element. In addition, there are pEM homologous sequences within the mitochondrial genome of the source strain Ag4, which contain pEM and pMPJ as extrachromosomal elements.Key words: Agaricus, plasmid, mitochondrial DNA.

Properties of Isolated Mitochondria of Agaricus Bisporus: Their Relationship to Dormancy and the Germination of Spores

1973 ◽  
Vol 31 ◽  
pp. 458-459
Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel
Keyword(s):  
Mitochondrial Dna ◽  
Ethidium Bromide ◽  
Microscopic Examination ◽  
Agaricus Bisporus ◽  
Osmotic Shock ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Isolated Mitochondria ◽  
Dna Strands ◽  
Cytoplasmic Ribosomes

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.

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.

scholarly journals Reduced Variation in Drosophila simulans Mitochondrial DNA

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1519-1528
Author(s):  
J William O Ballad ◽  
Joy Hatzidakis ◽  
Timothy L Karr ◽  
Martin Kreitman
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Evolutionary Dynamics ◽  
Selective Sweep ◽  
Mitochondrial Gene ◽  
Drosophila Simulans ◽  
Dramatic Reduction ◽  
Nucleotide Variability ◽  
Pooled Samples ◽  
Mitochondrial Gene Mutation

We investigated the evolutionary dynamics of infection of a Drosophila simulans population by a maternally inherited insect bacterial parasite, Wolbachia, by analyzing nucleotide variability in three regions of the mitochondrial genome in four infected and 35 uninfected lines. Mitochondrial variability is significantly reduced compared to a noncoding region of a nuclear-encoded gene in both uninfected and pooled samples of flies, indicating a sweep of genetic variation. The selective sweep of mitochondrial DNA may have been generated by the fixation of an advantageous mitochondrial gene mutation in the mitochondrial genome. Alternatively, the dramatic reduction in mitochondrial diversity may be related to Wolbachia.

scholarly journals Mitochondrial DNA Toxicity in Forebrain Neurons Causes Apoptosis, Neurodegeneration, and Impaired Behavior

2010 ◽  
Vol 30 (6) ◽  
pp. 1357-1367 ◽  
Author(s):  
Knut H. Lauritzen ◽  
Olve Moldestad ◽  
Lars Eide ◽  
Harald Carlsen ◽  
Gaute Nesse ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Cognitive Abilities ◽  
Natural Aging ◽  
Base Substitution ◽  
Behavioral Alterations ◽  
Adult Mice ◽  
Progressive Loss ◽  
Forebrain Neurons ◽  
High Level

ABSTRACT Mitochondrial dysfunction underlying changes in neurodegenerative diseases is often associated with apoptosis and a progressive loss of neurons, and damage to the mitochondrial genome is proposed to be involved in such pathologies. In the present study we designed a mouse model that allows us to specifically induce mitochondrial DNA toxicity in the forebrain neurons of adult mice. This is achieved by CaMKIIα-regulated inducible expression of a mutated version of the mitochondrial UNG DNA repair enzyme (mutUNG1). This enzyme is capable of removing thymine from the mitochondrial genome. We demonstrate that a continual generation of apyrimidinic sites causes apoptosis and neuronal death. These defects are associated with behavioral alterations characterized by increased locomotor activity, impaired cognitive abilities, and lack of anxietylike responses. In summary, whereas mitochondrial base substitution and deletions previously have been shown to correlate with premature and natural aging, respectively, we show that a high level of apyrimidinic sites lead to mitochondrial DNA cytotoxicity, which causes apoptosis, followed by neurodegeneration.

Linear plasmids that integrate into mitochondrial DNA in Neurospora

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 155-159 ◽  
Author(s):  
H. Bertrand ◽  
A. J. F. Griffiths
Keyword(s):  
Mitochondrial Dna ◽  
Rna Polymerase ◽  
Dna Polymerase ◽  
Inverted Repeats ◽  
Insertion Sequences ◽  
Long Terminal Repeats ◽  
Linear Plasmids ◽  
Mt Dna ◽  
Common Features ◽  
Mitochondrial Chromosome

In some field isolates of Neurospora from Hawaii and India, senescence is induced by integration of linear DNA plasmids, kalilo and maranhar, respectively, into mitochondrial (mt) DNA. Although the two plasmids show little homology at the DNA level, both have inverted long terminal repeats, and each potentially encodes a DNA polymerase and a RNA polymerase. Both plasmids generate very long inverted repeats of mtDNA at their ends upon integration into mitochondrial chromosomes. Hence, they appear to integrate by a mechanism that involves pairing of both ends of the plasmid with short stretches of homologous nucleotide sequences in mtDNA. This recombinogenic association apparently generates an origin for an unscheduled round of replication of mtDNA. In the process, the resulting two copies of the mitochondrial chromosome are joined to opposite ends of the plasmid. A model for the senescence-associated accumulation of mtDNAs with plasmid insertion sequences is proposed on the basis of common features that characterize senescence in a variety of filamentous fungi.Key words: Neurospora, senescence, plasmids, mitochondria.

Mitochondrial DNA polymorphism in a black fly, Simulium vittatum (Diptera: Simuliidae)

1998 ◽  
Vol 76 (3) ◽  
pp. 440-447 ◽  
Author(s):  
X Zhu ◽  
K P Pruess ◽  
T O Powers
Keyword(s):  
New York ◽  
Mitochondrial Dna ◽  
Rflp Analysis ◽  
Mitochondrial Haplotype ◽  
Black Flies ◽  
Mitochondrial Dna Polymorphism ◽  
Simulium Vittatum ◽  
Hybridization Probes ◽  
Restriction Sites ◽  
Mitochondrial Heterogeneity

Mitochondrial DNA (mtDNA) was extracted from pooled field-collected samples representing six species of black flies (Cnephia dacotensis, Simulium bivittaum, S. johansenni, S. luggeri, S. piperi, S. vittatum) and compared by restriction fragment length polymorphism (RFLP) analysis. Morphospecies were molecularly distinct, with few shared restriction fragments. Eleven populations of S. vittatum were found that appeared to be homogeneous for a single mitochondrial haplotype. Ten other populations of S. vittatum showed extensive mitochondrial heterogeneity. In part, these samples contained mixtures of two cytologically recognized siblings: IIIL-1 and IS-7. About 70% of the mitochondrial genome of a population pure for sibling IIIL-1 was cloned as five HindIII fragments, which were used as hybridization probes to examine individual black flies. Thirteen mtDNA haplotypes involving permutations of 10 HindIII restriction sites were identified in individual black flies examined from 26 populations. DNA from 168 larvae cut with both EcoR1 and HindIII revealed five additional haplotypes. One HindIII haplotype was present in 84% of 390 larvae examined and predominated in every population examined from New York to California and in both the IIIL-1 and IS-7 siblings. Nebraska populations had individuals with nearly all known haplotypes. The most common haplotype was usually the only form present in warm, silty streams with organic enrichment. Rarer haplotypes were found in cool, spring-fed streams but without clear geographic or phylogenetic components.

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