Hypotonic environment: swelling like bubbles

Hypertonic environment: elongated into a linear shape

Early stage: short rod-shaped

Late stage: long rod shape

Inner cavity (stromal cavity)

External space (intermembrane space)

crest

intercranial cavity

intracranial space

intimal translocon

outer membrane translocon

Intima: Cytochrome oxidase

Outer membrane: Monoammonium oxidase

Substrate: malate dehydrogenase

Intermembrane space: adenylate kinase

Transcription of the mitochondrial genome starts from two major promoters, the heavy chain promoter (HSP) and the light chain promoter (LSP). Transcription factors bind to it and initiate transcription under the action of mtRNA polymerase.

The transcription of mitochondrial genes is similar to the transcription of prokaryotes, that is, a polycistronic sequence is produced, including mRNA and tRNA.

Primary transcript I - tRNAphe, tRNAval, 12S rRNA and 16S rRNA

Primary transcript II -- mRNA and tRNA

origin of replication

The direction of synthesis of the heavy chain is clockwise

The direction of synthesis of light chains is counterclockwise

budding division

contraction split

septal division

NADH or FADH2 provides a pair of electrons, which pass through the electron transport chain and are finally accepted by O2;

The electron transport chain also functions as an H + pump, and the process of transferring electrons is accompanied by the transfer of H + from the mitochondrial matrix to the intermembrane cavity;

The inner mitochondrial membrane is impermeable to H + and OH, so as the electron transfer process proceeds, H + accumulates in the intermembrane cavity, causing a difference in proton concentration on both sides of the inner membrane, thereby maintaining a certain potential energy difference;

H + in the intermembrane cavity has a tendency to return to the matrix along the concentration gradient, and can pass through the ATP synthase complex F with the help of potential energy. The proton channels on the mitochondria penetrate into the mitochondrial matrix, and the free energy released drives ATP synthase to synthesize ATP.

The main manifestations of muscle damage are extreme intolerance of fatigue in skeletal muscles, and the main manifestations of nervous system include external ophthalmoplegia, stroke, recurrent epilepsy, myoclonus, migraine, ataxia, intellectual disability, and optic neuropathy. Other system manifestations include extreme fatigue intolerance of skeletal muscles. Manifestations may include heart block, cardiomyopathy, diabetes, renal insufficiency, intestinal pseudo-obstruction, and short stature.

Pathogenesis: mtDNA8344G mutation → overall level of mitochondrial protein synthesis ↓ → reduced content of oxidative phosphorylation components other than complex II (especially reduced content of respiratory chain enzyme complexes I and IV).

Mitochondrial encephalomyopathy can be divided into several categories according to different clinical syndromes:

It is a maternally inherited disease of optic neurodegeneration. The majority of patients are male, and the disease usually occurs between the ages of 15 and 35. The main clinical manifestations are acute or subacute painless vision loss in both eyes simultaneously or successively, which may be accompanied by loss of central visual field and color vision impairment. The severity of visual impairment varies greatly, ranging from completely normal, mild, moderate to severe.

The main biochemical defect of LHON is complex I deficiency, and the genetic abnormality is a translocation mutation at the 11778 position of mtDNA. In addition, 14484 and 3460 point mutations have been reported.

It is a rare eye movement disorder disease. It is a chronic, progressive, and bilateral disease. It starts with ptosis, gradually develops eye movement disorders, and finally the eyeball becomes immobile. The causes include trauma, toxins, degeneration, genetic diseases and tumors.

Also known as subacute necrotizing encephalomyelopathy, it is an inborn metabolic disorder caused by the loss of respiratory chain subunits. It is a mitochondrial encephalomyopathy. It usually begins between February and 6 years old and dies within weeks or months. The vast majority of children die before the age of 2 years.

The more characteristic clinical manifestations of those with onset in infancy include: intermittent respiratory rhythm abnormalities, external ophthalmoplegia, nystagmus, ataxia, and audio-visual impairment, while those with onset in early childhood have more prominent manifestations of myasthenia. Most children will have severe lactic acidosis.