I have long regarded the mitochondrion as an electrical device and this topic has been covered several times in previous blogs. Recently I built a physical electronic analogue of the mitochondrion and details of this follow in the appendix to this article.
What I found to my surprise as a biochemist, but not to the surprise of any electronic engineer, that I had built a simple oscillator. The oscillation period was remarkably constant with varying capacitance and collapsed catastrophically when the leak current was too great to charge the capacitor or when the electrical energy input was too low. For interest I outputted the charging and discharging of the capacitors through the signal software called SonicPy. I could now listen to the heartbeat of my model.
To cut a long story short and confine the details to the appendix, it was clear that my model had a lot in common with how real aging mitochondrial behave but new to me was that if the capacitance model is correct then the mitochondrion is a natural oscillator. In electronics an oscillator is constructed by pairing a capacitor with an inductor. This is basically what is described below in the electronic analogue.
Mitochondrial oscillations are extensive, well documented and always involve energy dependent ion transfers.1,2, They have variable periods from 10 to 100s of cycles per second(Hz). ‘New Agers’ in particular love the 10Hz periods as it maps to the resting Alpha waves of the brain. By the by, my toy model often settled at a similar frequency.
If however you have come across notions that bacteria and by inference mitochondria emit radio signals ( very likely given this model) and are worried about 5G the Ghz frequencies causing interference it would be possible to imagine resonance but not with the cycling frequencies described above!
It follows indeed, in general, that an oscillation electrical device will interact with external oscillators such as electromagnetic waves and it is inevitable that resonance energy transfer will play a part at some frequencies.
To summarise, researchers are fascinated by the oscillations in cells and bacteria that they have found. They even speculate about the fabulous internal clock and broadcasting microbes . I would subscribe to both theories but here I am proposing that the drum-beaters in eukaryotes are the mitochondrion and that it is an inevitable result of of their simple electronics.
Appendix
A model of the mitochondrion as capacitor and oscillator
The mitochondrion is well understood to be an electrochemical structure but increasingly I think I regard it as an electrical device made from biological molecules. Mostly for fun I have created a simple electrical analogue, a picture of which is shown below.
I am able to vary energy input, membrane electrical capacitance and trans-membrane leak of charge. Or rather, I can vary electrical analogues of these well known parameters. The set up is explained below.
Fig 1 Breakout boards attached to RaspberryPi
Fig 2 Sketch of Fig
How the circuit works:
A light dependent resistor (LDR) receives light from light emitting diode (LED). The intensity of light is controlled manually by moving green lever (30 degrees varied light from max to zero).
5V DC is supplied from Raspberry Pi. GPIO1 pin goes high when capacitor(s) reach approx 75% charge and is then read by Pi. The greater the supply of energy to the capacitors( in this setup this equals a lower LDR’s resistance) the quicker the capacitor is charged. In other words the more light that falls on LDR the quicker the capacitor(s) charges.
So in analogy, the mitochondrion’s membrane potential is represented by the capacitance and the ability to charge the mitochondrion from electrons received from substrates is represented by the light intensity.
The total capacitance has two values ( 1 and 2 uF ) a variation from LOW to HIGH is achieved by the Raspberry PI controlled transistor switch (GPIO2).
In analogy, low capacitance represents mitochondria with low internal surface area and vice-versa those with high surface areas. The former would be megamitochondria found in aged cells and the latter the sum of many smaller mitochondria. (or complex reticulate mitochondria in younger cells).
A variable resistor connected to ground is adjusted manually which acts as a ‘bleed’ and inhibits the charging of the capacitors. As the leak increases the time taken to charge the mitochondrion increases very slightly until it fails catastrophically.
This resistor is meant to be analogous to membrane leaks which are known to increase with age. Ultimately depolarization leads to the cascade of events that ends in apoptosis.
Finally, an air-core solenoid takes the capacitors to ground.
The mitochondrial respiratory chain is aggregated into super-structures called ‘respirasomes’ which have a distinctly spiral conformation. I am assuming the even with electron tunnelling the path followed by electrons will be a spiral thus creating the effect associated with electrical solenoids, that is storage of energy and opposition to current change.
I could ‘listen’ to the capacitors charging and discharging by outputting to sound software called SonicPy whilst manually varying the light intensity and current leak.
1.`Adv Exp Med Biol. 2008; 641: 98–117.
PMCID: PMC2692514
NIHMSID: NIHMS111938
PMID: 18783175 Mitochondrial Oscillations in Physiology and Pathophysiology
Miguel A. Aon, Sonia Cortassa, and Brian O’Rourke*
2. Effects of nanosecond pulsed electromagnetic field on mitochondrial membrane potential∗Wenjun Xu ; Xueling Yao ; Jingliang Chen. IEEE Xplore
