Mitochondrial matrix
The cytosolic, intermembrane space, compartment has a water content of 3.8 μl/mg protein, while the mitochondrial matrix 0.8 μl/mg protein. It is not known how mitochondria maintain osmotic balance across the inner mitochondrial membrane, although the membrane contains aquaporins that are believed to be conduits for regulated water transport. Mitochondrial matrix has a pH of about 7.8. Mitochondrial DNA was discovered by Nash and Margit in 1963. One to many double stranded mainly circular DNA is present in mitochondrial matrix. Mitochondrial DNA is 1% of total DNA of a cell. It is rich in Guanine and Cytosine content. Mitochondria of mammals have 55s ribosomes.
Microsporum nanum
Mitochondrial DNA sequences have been used for phylogenetic studies in the dermatophytes. A typical fungal mitochondrial DNA usually contains 14 conserved protein-coding genes, 22 to 26 tRNA gene, and 2 rRNA genes. The difference of mitochondrial DNA between fungal species is due to the variations in intergenic region, intron, and gene order. The complete sequences of "Trichophyton rubrum", "T. mentagrophytes", "T. ajelloi", "M. canis", "M. nanum", and "Epidermophyton floccosum" show that these 6 species in dermatophytes are closely related because their mitochondrial genomes are highly conserved. Genome size of mitochondrial DNA in "M. nanum" is 24,105 basepairs. The DNA is AT-rich and the GC content is only 24.47%. "M. nanum" mtDNA has 15 protein-coding genes, including ATP synthase subunits "atp6", "atp8", and "atp9", cytochrome oxidase subunits "cox1", "cox2", and "cox3", apocytochrome b "cob", a ribosomal protein "rps5", and NADH dehydrogenase subunits "nad1", "nad2", "nad3", "nad4", "nad5", and "nad6". The gene order of the 15 conserved protein coding genes in "M. nanum" mtDNA is identical to that of "T. rubrum", "T. mentagrophytes", "T. ajelloi", and "M. canis". The "Microsporum nanum" mtDNA also contains 2 rRNAs and 25 tRNAs. In addition, this mitochondrial genome is highly compact because 83.76% are structural genes. Moreover, the genome contains one intron and one intronic ORF.