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.
Health of Charles Darwin
The pathologist John A. Hayman of the University of Melbourne has presented a case that Darwin's symptoms indicate that he suffered from cyclic vomiting syndrome (CVS), an illness associated with mitochondrial DNA abnormalities. His paper on the topic was accepted by the "BMJ" and the "Medical Journal of Australia", and was published in December 2009. In a supplement published in February 2012, he proposed that stroke-like episodes of memory loss and partial paralysis which do not occur with CVS are characteristic of the MELAS syndrome. An A3243G mtDNA mutation has been found in 80% of patients with this syndrome, and has also been described in those with CVS. This mutation in mitochondria is associated with symptoms of intestinal problems, seasickness and Ménière's disease as well as CVS and MELAS syndrome, thus giving a shared source of the various problems that affected Darwin. Any mitochondrial disease would have been inherited from his mother Susannah Darwin, whose own mother had 8 other children. Some of them had illnesses which could have been related to the same mutation.