Related Experiment Video

Updated: Jul 18, 2026

Visualizing Bacteria in Nematodes using Fluorescent Microscopy
09:02

Visualizing Bacteria in Nematodes using Fluorescent Microscopy

Published on: October 19, 2012

Characterization of a novel plasmid DNA found in mitochondria of N. crassa

R A Collins, L L Stohl, M D Cole

    Cell
    |May 1, 1981
    PubMed

    Insights

    Researchers discovered a novel plasmid DNA within the mitochondria of N. crassa. This unique mitochondrial plasmid lacks homology to mitochondrial DNA and exhibits distinct genetic features, including unusual restriction enzyme site clusters.

    Area of Science:

    • Molecular Biology
    • Genetics
    • Mycology

    Background:

    • Mitochondria contain their own genetic material, separate from the nuclear genome.
    • Extrachromosomal DNA elements, such as plasmids, can exist within organelles.
    • The genetic makeup of N. crassa mitochondria is not fully characterized.

    Purpose of the Study:

    • To identify and characterize novel DNA elements within N. crassa mitochondria.
    • To investigate the nature and origin of extrachromosomal DNA in N. crassa mitochondria.
    • To determine the transcriptional activity of the identified mitochondrial DNA.

    Main Methods:

    • Isolation of mitochondrial DNA from N. crassa strain Mauriceville-1c.
    • Restriction enzyme digestion and analysis of plasmid DNA.
    • RNA gel transfer hybridization to detect transcripts.

    Main Results:

    • Identification of a novel plasmid DNA in N. crassa mitochondria.
    • The plasmid DNA is circular, with a monomer length of 3.6 kb, and exists as an oligomeric series.
    • Unusual clusters of Eco RI and Pst I restriction sites were observed.
    • A major transcript of 3.3-3.4 kb, close to monomer length, was detected, suggesting transcriptional activity.

    Conclusions:

    • A unique mitochondrial plasmid DNA has been identified in N. crassa.
    • This plasmid shows no homology to the organism's mitochondrial DNA.
    • The plasmid DNA likely contains functional elements for transcription initiation and termination.

    More Related Videos

    Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing07:24

    Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing

    Published on: February 10, 2023

    Mitochondrial Transformation in Baker's Yeast to Study Translation and Respiratory Complex Assembly09:53

    Mitochondrial Transformation in Baker's Yeast to Study Translation and Respiratory Complex Assembly

    Published on: June 7, 2024

    Related Concept Videos

    Genomic DNA in Prokaryotes00:46

    Genomic DNA in Prokaryotes

    The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance.
    Genomic Diversity in Bacteria
    Although bacterial genomes are much...
    Non-nuclear Inheritance01:29

    Non-nuclear Inheritance

    Most DNA resides in the nucleus of a cell. However, some organelles in the cell cytoplasm⁠—such as chloroplasts and mitochondria⁠—also have their own DNA. These organelles replicate their DNA independently of the nuclear DNA of the cell in which they reside. Non-nuclear inheritance describes the inheritance of genes from structures other than the nucleus.
    Animal Mitochondrial Genetics02:59

    Animal Mitochondrial Genetics

    Among all the organelles in an animal cell, only mitochondria have their own independent genomes. Animal mitochondrial DNA is a double-stranded, closed-circular molecule with around 20,000 base pairs. Mitochondrial DNA is unique in that one of its two strands, the heavy, or H, -strand is guanine rich, whereas the complementary strand is cytosine rich and called the light, or L, -strand. Compared to nuclear DNA, mitochondrial DNA has a very low percentage of non-coding regions and is marked by...
    Export of Mitochondrial and Chloroplast Genes02:19

    Export of Mitochondrial and Chloroplast Genes

    A eukaryotic cell can have up to three different types of genetic systems: nuclear, mitochondrial, and chloroplast. During evolution, organelles have exported many genes to the nucleus; this transfer is still ongoing in some plant species. Approximately 18% of the Arabidopsis thaliana nuclear genome is thought to be derived from the chloroplast’s cyanobacterial ancestor, and around 75% of the yeast genome derived from the mitochondria’s bacterial ancestor. This export has occurred irrespective...
    Nucleoid01:24

    Nucleoid

    The nucleoid represents a structurally and functionally distinct region within prokaryotic cells, where the cell's DNA and associated proteins are housed. Unlike eukaryotic cells, prokaryotes lack a membrane-bound nucleus, and the nucleoid facilitates the organization and accessibility of the genetic material within this constraint. The DNA in most bacteria and archaea exists as a single, circular, double-stranded molecule that is highly compacted through supercoiling and interactions with...
    Plasmids01:28

    Plasmids

    Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...