Mitochondria and their host.

Mitochondria and their host.

A relationship still in the making.

This article follows the previous post on the regulation of mitochondrial division by their ancestral ‘host’ cell. In this post I put forward the idea that in the post-mitotic somatic cell, mitochondrial proliferation must be inhibited (and must have always been inhibited) in order to prevent mitochondria from behaving like a bacterial infection rather than, as now, the essential symbiont in the aerobic eukaryote cell. The price for such suppression, I speculated, is senescence and cell death an idea I developed from my own work on regenerated liver mitochondria from senescent rats.1

In this post I wish to explore further the relationship between mitochondria and their host. After half a billion years of coexistence we consider mitochondria to be fully integrated with the ancestral host. It is clear that so much of their construction has been handed over to nuclear DNA and little remains to the mitochondrial DNA. However, even though much evolutionary time has elapsed I increasingly see the endosymbiotic relationship as a ‘work still in progress’.

To see the work in progress look for where the ‘joins’ are. That is to say, the junctures where the host’s biochemistry joins with that of the mitochondrion. Below are three areas where ‘the join shows’.

Getting Fat

The junction between glycolysis (the ancestral fermentation route for the production of chemical free energy) and the oxidative metabolism of the mitochondria is an obvious junction. Here, essentially, the products of glycolysis (fermentation) are taken to be fully oxidised by mitochondria thereby increasing the amount of energy available to the organism by an order of magnitude.

Essentially this is a hand-over process:  simple sugars such as glucose and fructose absorbed directly from the diet into the bloodstream are taken up by  cells or stored stored in the muscles and liver as glycogen. These sugars enter the glycolysis pathway mentioned above and are swiftly converted to what is essentially ‘mitochondrial fuel’.

A good supply of fuel is all well and good but what if there is a glut? Maybe the cell does not need much energy at this time and as a result the mitochondria are not accepting any more ‘fuel’. This is a bottle-neck  and can only be safely resolved by shunting off the accumulating fuels into an inert store. Fortunately Nature has provided a fix and this is exactly what happens...we know this store as fat.

In short here we see evolution acting  in typical kludge mode, stitching together two disparate systems and creating a ‘work around’ for some of the consequences. There is still a problem though. In the post mitotic cell mitochondria are obliged to age. This means that the sugar-produced (glycolysis/fermentation is sugar based) bottle-neck  becomes inevitable.

Indeed as we humans age one very well reported change is our tendency to get fatter. Few, over 25 years old, trying to control their weight will have failed to notice that carbohydrate-rich foods seem to have a disproportionate ability to fatten us up.

Something is not quite going well with traffic flow at the junction!  I think this is a good example to start with to illustrate the evolution of a working relationship between two biochemistries. A second example shows ( to my viewpoint) that the ancestral cell nearly abandoning the energetic payload of their guests.

Cancer

There has always been a paradox at the heart of rapidly growing tumours and that is the apparent contradiction between rapid cell division and growth and the paucity of mitochondria found in tumour tissue. Division and growth require energy and conventional wisdom has it that the explosion of multicellular life was down to the ‘new’ eukaryote cell with its abundance of energy resulting from its symbiosis with mitochondria.

Recent work on the cell’s energy economy suggests that the cost of building new mitochondria, (which would by the way involve unleashing mitochondrial division) is simply not worth the ‘expense’ as the basic cell, unburdened of the high energy needs of a liver, a brain or a muscle, can rely quite nicely on anaerobic metabolism alone. 2

Indeed I found that mitochondria from rapidly growing tumours produced in aged mice were indeed few in number but in all other respects identical to those found in young rats, so it’s not that the tumour cannot build good mitochondria they simply choose not to build that many of them. However they do have mitochondria and they do use their cytoskeleton to gather and to wrap these around the nuclei as would be the case in normal cells prior to mitosis..3

I think this part of the relationship between the cell ‘host’ and the mitochondrion is the key to multicellular development half a billion years ago. In a previous post with material taken from my thesis I developed a capacitance model for mitochondrial energy storage. During mitosis a cell cannot feed, yet a complex nucleus would require a lot of energy to divide. I think energy this is stored electrochemically in the capacitance of the mitochondria surrounding the nucleus.

In other words, the true utility value of the mitochondria to the cell is to power cell division. The specialised high energy functions used by differentiated tissues such as nerves and muscles came later. Below is my final example. Here I see mitochondria drawing a line in the sand with regard to their function. In this case the composition of their inner mebranes and from this their electrical integrity and ability to produce energyt through oxidation.

Cholesterol

Cholesterol is essential to mitochondrial function. The inner membrane of mitochondria is electrochemically speaking precisely engineered, It’s ionic permeability and dielectric properties are essential to its function. The level of cholesterol in the membrane is highly conserved, that is it is kept at a certain level come what may. In my work feeding rats very high levels of cholesterol produced an expected increase in cholesterol in all cellular structures which normally contained some cholesterol… but not though the mitochondrial inner membrane: it remained unmoved.  So did the respiratory functions of the mitochondria which did not change with excess cholesterol in the cell..4

The converse experiment is very hard to do. Producing a cholesterol deficit is difficult as most animals including ourselves and the rat can produce cholesterol in the liver without a dietary source. Today this can be achieved easily using the drugs known as statins. These block cholesterol synthesis so on a low cholesterol diet a deficit can be easily produced. I can find little work on cholesterol deprivation on mitochondrial function but it has been shown that simvastatin reduces mitochondrial function in yeast. It may be that many of the reported side effects in aged humans on low cholesterol diets whilst on statin drugs may be due to adverse effects on already struggling mitochondria. 5

The bad side of cholesterol, that is arterial disease, may be a nasty side effect of the absolute requirement to meet the cholesterol needs of the energy producers, the mitochondria. This would be critical in tissues like the brain and muscles which rely heavily on a high energy economy.

To conclude, I think there is profit in looking at the relationship between mitochondria and their hosts. Compromises of co-existence honed and developed by the pressures of evolution will be everywhere the two biochemistries meet. I think I have highlighted just three.

1. REVERSAL OF AGE-DEPENDENT DECLINE IN RESPIRATORY CONTROL RATIO BY HEPATIC REGENERATION HORTON, AA; SPENCER, JA  FEBS LETTERS  Volume: 133   Issue: 1   Pages: 139-141   DOI: 10.1016/0014-5793(81)80490-5   Published: 1981 Times Cited: 4 (from Web of Science)

     2) Overflow metabolism in Escherichia coli results from efficient proteome allocation:

Markus Basan, Sheng Hui,Hiroyuki Okano, Zhongge Zhang, Yang Shen, James R. Williamson& Terence Hwa

Nature 528,99–104(03 December 2015) doi:10.1038/nature15765

‘Using experimental proteomics and modelling in E. coli, the amount of protein needed to run respiration (per ATP produced) is shown to be twice as much as that needed to run fermentation’

    3) Biochimica et Biophysica Acta (BBA) - BioenergeticsThe relationship between mitochondrial shape and function and the cytoskeleton  Vasiliki Anesti, Luca Scorrano, Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, Via Orus 2, I-35129, Padova, Italy Received 13 January 2006, Revised 13 March 2006, Accepted 7 April 2006, Available online 19 April 2006

     4) The Cholesterol Content of Mitochondria from Mature and Old Rats P151-160

Age-related changes in Rat Liver Mitochondria J A Spencer Ph.D thesis 1980 Birmingham University, unpublished work.

5) Simvastatin reduces ergosterol levels, inhibits growth and causes loss of mtDNA inCandida     glabrata Christiane Westermeyer & Ian G. Macreadie CSIRO

Health and Molecular and Technologies and P-Health Flagship, Parkville, Victoria, Australia

All publications by J Spencer:

Title: REVERSAL OF AGE-DEPENDENT DECLINE IN RESPIRATORY CONTROL RATIO BY HEPATIC REGENERATION Author(s): HORTON, AA; SPENCER, JA Source: FEBS LETTERS  Volume: 133   Issue: 1   Pages: 139-141   DOI: 10.1016/0014-5793(81)80490-5   Published: 1981 Times Cited: 4 (from Web of Science) Title: Age-Dependent Decrease in Succinate Oxidase Activity on Re-addition of Cytochrome c to Depleted Mitochondria Author(s): Spencer, John A.; Horton, Alan A. Source: BIOCHEMICAL SOCIETY TRANSACTIONS  Volume: 7   Pages: 1260-1262   DOI: 10.1042/bst0071260   Part: 6  Published: DEC 1979 Times Cited: 2 (from Web of Science)	Title: DECLINE IN RESPIRATORY CONTROL RATIO OF RAT-LIVER MITOCHONDRIA IN OLD-AGE Author(s): HORTON, AA; SPENCER, JA Source: MECHANISMS OF AGEING AND DEVELOPMENT  Volume: 17   Issue: 3   Pages: 253-259   DOI: 10.1016/0047-6374(81)90062-2   Published: 1981 Times Cited: 17 (from Web of Science) Title: Differential Effect of Digitonin on Liver Mitochondria from Old and Mature Rats Author(s): Spencer, John A.; Horton, Alan A. Source: BIOCHEMICAL SOCIETY TRANSACTIONS  Volume: 7   Pages: 673-675   DOI: 10.1042/bst0070673   Part: 4   Published:AUG 1979 Times Cited: 0 (from Web of Science)
Title: AGE-DEPENDENT RELEASE OF MATRIX PROTEINS FROM RAT-LIVER MITOCHONDRIA Author(s): SPENCER, JA; HORTON, AA Source: EXPERIMENTAL GERONTOLOGY  Volume: 13   Issue: 3-4   Pages: 227-&   DOI: 10.1016/0531-5565(78)90016-5  Published: 1978 Times Cited: 7 (from Web of Science)	The simultaneous oxidation of substrates by rat liver mitochondria [proceedings]. Authors   Spencer JA, Barrett MC, Horton AA. Biochem Soc Trans. 1978;6(1):161-4.

Aging, Mitochondrial proliferation and epigenetics

Mitochondria represent a huge metabolic resource for the eukaryotic cell due to the simple fact they confer a huge ten-fold ‘turbo-boost’ to the low-energy fermentation-like respiration indigenous to the archaic cell.

Mitochondria came to live within their host organism probably 2 billion years ago. However, even though now largely tamed by their host, their complexity and atavistic ability to divide and reproduce mean that this boost comes with a risk and a cost.

In rapidly reproducing cancer cells for example, mitochondria are largely ditched in favour of the old fermenting ways, simply because a ‘quick and dirty’ replication of the whole cell without making and supporting a whole load of mitochondria carries a lower energetic cost than would the fully functioning mitochondria-rich model. Cancer cells must know how to suppress mitochondrial replication.

Mitochondrial replication and proliferation within a cell must have been a real headache in the earliest days as in effect the ‘visitor’ was a bacterium swimming in a soup of intracellular nutrients ... perfect for reproduction. Parasitic bacterium to symbiotic mitochondrion is a big step. Early on and relatively simply, the host cell must have had the ability to control the mitochondrion’s rate of division and most probably this would have involved a widely used pathogen defence mechanism.

In the present day postmitotic somatic cell, I think this control is basically set to ‘on’ and moreover therein lays the key to the aging mitochondrion and in turn the aging cell. The intense free radical-rich environment generated by mitochondria results in (well documented) damage and the ‘repair bills’ for this activity most likely mount up over time ... but without the ‘start-over’ option invoked by replication the mitochondria will senesce. They enlarge and eventually trigger apoptosis as they start to leak.

In a paper taken from my thesis, livers from very old rats in senescence were induced to regenerate following partial hepatectomy. To cut a long story short the ‘new’ tissue hosted mitochondria that were indistinguishable from those found in young rats as well as fewer ‘legacy’ mitochondria morphologically similar to those from older rats. The conclusion was that dividing mitochondria are built ‘as new’ from undamaged blueprints, even in senescent cells.

What follows is speculation. What can be a the simple mechanism for controlling mitochondrial division be? My candidates are the histone proteins. They are present in the ancient bacteria the archaea which can carry out phagocytosis. That is they can ingest smaller organisms in the manner the putative ancestral eukaryote did with mitochondria. Histones are toxic to mitochondria and can bind to them and kill them. Histones also accumulate in liposomes ( fatty droplets within the cell) and can be used to kill invasive bacteria in some eukaryotic tissues.

Histones ( and there are a great many to choose from) therefore could form the basis of a regulatory system to prevent mitochondria from uncontrolled proliferation in the post mitotic cell.

If so, then this begs the question whether there is any epigenetic route to change this control. Maybe to allow a bit more mitochondrial proliferation and thus to rejuvenate a cell. In my thesis two populations of mitochondria were always present in rat liver preparations, the ……… increasing with age and decreasing with hepatic regeneration. So far the B and D vitamins seem the most promising having both been shown to modify histone acetylases and methylations. As is well known Vitamin D deficiency is linked with age-related dementia and B12 along with B6 and B5 to many of age - related ailments

As stated previously this is speculation but the possibility of an epigenetic back door into mitochondrial well being is deeply attractive.

Mitochondrial morphology and Ageing

The possible effects of mitochondrial inner membrane surface area to volume ratios on their electrochemical capacity.

Synopsis:

I argue that age-related enlargement of mitochondria accompanied by a loss of internal folding (christae) is a morphological response to progressive inner membrane porosity and represents an attempt to maintain  ΔΨ at a threshold level needed to synthesise ATP.  A corollary of this effect is to reduce teh capacity of a mitcohondrion to produce a sustained flow of energy, a characteristic of old age itself. 

The argument is made by modelling mitochondria as simple electrical capacitators which in circuits perform the role of energy supply, storage and regulation (smoothing). 

In my Ph.D thesis of 1980 I reported the, now well documented, appearance of larger than normal mitochondria with diminished internal christal folding (1) in the liver cells of senescent rats. I hypothesised then as now that this would have an effect on the charge separation across the membrane known as the membrane potential ΔΨ.

Mega mitochondria, as they are called, are often observed in cells just prior to apoptosis (2,3) and so it is reasonable to propose that this kind of morphological change has biological significance.

In this article I will propose that the enlargement of of mitochondria is an adaptive response to age-related energetic stress which has the effect of maintaining, in a situation of increased leakage of charge, a trans-membrane potential high enough to provide sufficient free energy for the synthesis of ATP.

A corollary of this change is that larger mitochondria with fewer christae, although able to produce ATP, have a lower capacity to generate it continuously in proportion to their reduced membrane area. In other words they 'get tired' more rapidly than their younger counterparts.

In order to explain my proposal I have adopted a simple electronic model of the mitcohondrion as a charge storage device known to all as the capacitor. The mitochondrion-as-capacitor has much in common with the simple electronic capacitor. As with a capacitor a mitochondrion has a membrane potential measured in volts, a flow of charge measure in coulombs and a charge capacitance measured in farads. Like the foils and insulators in a capacitor the mitochondrial membrane has a measurable dielectric constant and like the capacitor it leaks away charge at a rate determined by its membrane integrity and dielectric constant. 

Finally like the capacitor, the free energy stored by the mitochondrion obeys the Nernst equation and is thus a function of the degree of charge separation ( potential difference) and the total surface area over which the charge is separated. With all of the above mind I have created a model that demonstrates that the capacity of a mitochondrion to generate ATP depends critically on the surface are to volume ratio of the inner mitochondrial membrane.

The Mitochondria as Capacitor

It has been my view for 35 years that mitochondria should be regarded as bio-electrical charge storage devices which can be 'tapped' for stored free-energy on demand via the agency of the ATP-synthetase complexes. 

I see them as mini mobile capacitors insulated from each other and their surroundings by high-dielectric outer-membrane ' shielding wrappers', racing from place to place within the cell to where demand is highest or arranged in arrays as batteries to power muscles or joining together to form high capacity reticulate structures surrounding the nucleus during cell division as energy stores.

I also see the emergence of enlarged mitochondria with fewer christae in-folds in ageing cells as a sign that they are struggling to keep their charge high enough to have sufficient threshold free energy to synthesise ATP.  As they age mitochondria produce increased amounts of free radicals (4) a sign of decreased structural integrity of the inner mitochondrial membrane which I also see as an increase in the rate at which charge is being lost from the membrane. This is analogous to the 'charge leakage' of a capacitor.

I found no evidence from my own research that aged rat liver mitochondria were unable to produce ATP (5) as well as younger mitochondria but it is important to appreciate, that as with electronic capacitors, a potential difference will be maintained at a level set by the rate at which charge is supplied minus the rate at which charge is being lost. It's the old problem of filling a bath with the plug out. How fast is it filling, how big is the bath and how fast is it flowing out? The diagrams below illustrate how I imagine this works.

A water analogy for mitochondrial capacitance where H measures the 'head of water' needed to produce sufficient pressure (ie voltage V ) to produce free energy for ATP synthesis. X is the rate of supply of electrons from substrates metabolised by mitochondria; y is the rate of leakage or loss of charge and z is the rate of production of ATP.

The water analogy follows the Nernst equation in all respects; the key variable in the visual analogy being H the 'voltage' required to make ATP. It can be seen that the rate of filling and leaking of the bath will determine how quickly H is reached. ATP can then  be drawn off at a rate that does not allow H to fall below its critical value.

It should be clear that the rate (z) at which ATP can be drawn depends on the difference between filling and leaking ( x-y) once H has been reached. If y increases or x decreases for whatever reason, as long as x>y, then the critical value of H can be reached. 

However crucially it is reached much more quickly if the capacitance of the bath is reduced.

The Nernst equation:

In the above: E is the free energy needed to synthesise ATP;  R,T and F are respectively the Gas Constant, the absolute temperature of the system and the Faraday Constant. What is left is the charge transferred (z) and the potential difference in Volts between the inner and outer sides of the mitochondrial membrane

Older larger mitochondria with fewer cristae have a smaller surface area to volume ratio than their highly folded younger counterparts. This means that as with an electrical capacitor they will more readily reach their working voltage when supplied with charge but will have a lower capacitance and thus less total energy ( measure in Joules) available to do work.

Also, the proportion of the stored energy that has the threshold voltage needed to synthesis ATP will fall very rapidly as the charge is drawn off.  Energy in joules is the product of the voltage ( across the membrane) and the amount of electrons or available charge measure in coulombs. 

The equation below summarises the relationship as described for a conventional electronic capacitor.

Joules = volts x coulombs

This relationship in my model also defines the basic energetics of a mitochondrion. 

Discussion

While a cell remains viable the mitochondria maintain sufficient electrical integrity to provide the membrane potential needed for the synthesis of ATP. Cell death, apoptosis, is preceded by the loss of membrane integrity leading to leakage and loss of potential. As they age mitochondria are able to compensate for membrane deterioration by morphological changes.

My assertion is that by becoming bigger with fewer christae they are are able to maintain a critical membrane potential despite a higher leakage of charge. The trade off is a sacrificing of capacity leading to the characteristic loss of energy in old age. Support for this idea is provided by modelling a mitochondrion against an electronic capacitor which would behave in an identical manner.

As a corollary it is possible to see the mitochondrial outer membrane less as a nondescript wrapper, a boundary and no more for the mitochondrion to become a more active component analogous to the shielding wrappers of electronic capacitators.

Outer membranes are particularly responsive in their composition to diet. High cholesterol diet increases the concentration of cholesterol in the outer membrane (9) and hence its dielectric constant. The outer membranes of sperm mitochondria (10) have high concentration of selenium to protect against free radical damage. I suspect there is a lot more to learn about the role of the outer membrane.

References; 

1. Age Related Changes in Rat Liver Mitochondria. pp182-188   John Spencer Thesis Birmingham University 1980.

2. Subcellular changes and apoptosis induced by ethanol in rat liver 

Subcellular changes and apoptosis induced by ethanol in rat liver *Antonio Benedetti, Eugenio Brunelli, Roberto Risicato, Teresa Cilluffo, Anne Marie Jézéquel, Francesco OrlandiPostgraduate School of Gastroenterology and Institute of Experimental Pathology, University of Ancona, School of Medicine, Ancona (Italy) 1987


3.Implication of mitochondria in apoptosis. Detection of Mitochondrial Diseases, Developments in Molecular and Cellular Biochemistry Volume 21, 1997, pp 185-188 Patrice Xavier Petit, Naoufal Zamzami, Jean-Luc Vayssière, Bernard Mignotte, Guido Kroemer, Maria Castedo

4 BARJA, G. (1998), Mitochondrial Free Radical Production and Aging in Mammals and Birds. Annals of the New York Academy of Sciences, 854: 224–238. doi: 10.1111/j.1749-6632.1998.tb09905.x

5 : DECLINE IN RESPIRATORY CONTROL RATIO OF RAT-LIVER MITOCHONDRIA IN OLD-AGE

Author(s): HORTON, AA; SPENCER, JA Source: MECHANISMS OF AGEING AND DEVELOPMENT  Volume: 17   Issue: 3   Pages: 253-259   DOI: 10.1016/0047-6374(81)90062-2   Published: 1981

Windows 10 in schools.

‘One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind them’  Lord of the Rings J.R.R. Tolkein

An article in CWuk by Charlotte Gee ‘Government seeks suppliers for £300 million education ICT tender’ awoke me from my deep educational  Smaug-like sleep. This framework replaces the defunct 2010 BECTA framework: yes BECTA!, how I miss them. But what stirs? Where has all this treasure come from and who will get the gold from the mountain?

First a bit of background. School ICT has been moribund for many years, over 60% of schools have officially deprecated XP PCs and battery-less laptops. No one is spending on ICT and even if you wanted to upgrade (as they used to charmingly call it..it’s actually code for ‘buy a slower computer’) you will find that Microsoft will not now sell you Windows 7 or 8..that’s really true.

Meanwhile every kid and granny has a tablet computer, a Facebook account and a smart phone. Schools are left with grandad trousers and threadbare corduroy jackets. Not the image a £200,000 a year Academy principal wants to go with his/her Beemer.

If they buy a tablet, which tablet? Is it ‘compatible’ say the ICT technicians who cannot really believe that they still have jobs tending the olde networke. The problem actually was solved ages ago: sign up to Google’s education cloud, buy Android tablets/phones and Chrome OS...dah dah all done. Low maintenance, cheap and cheerful. I worked in a college that has done just that, so I know it works.

Now back in the real world. ICT is supplied to schools largely by outsourced mega service companies such as Capita, RM and Northgate.  They are by historical necessity purveyors of all things Microsoft and it would be a surprise if they were not amongst the suppliers for the new £300 million framework.  What will they flog to the unfortunate be-suited saps responsible for ICT procurement? Will they make wiser decisions this time?

Yes, Windows 10 is about to arrive. It will ‘work’ on everything:  a smart watch ( think PE department); a phone (think no-one at all) a tablet ( aka make-up mirrors); laptops and desktops PCs ( Think network technicians). We need a Cloud to store all the kids work. Oh yes and Azure G-Cloud.

What a bundle, what a spending spree, what a lock in!. It makes me so nostalgic. Bring back BECTA

Beating the System..The Rise of the Robot.

'O brave new world, That has such people in't! ' 

'You can't beat the system' was one of the first things I was told on joining a vast multinational company forty years ago. In the intervening years systems and processes have become intrinsic to all manifestations of organised labour. The very notion of beating systems is now a ludicrous self-indulgence for all who live within society.

I left the multinational company for the freedom that teaching offered. It was a good move and teaching provided a rich and rewarding environment for this independent minded scientist. All good things come to an end and 'systems' came to education: now unbeatable, intricately elaborate and all-pervasive they have ground and dumbed education down into atomised processes.

It seems if you speak to anyone, in whatever walk of life, you will hear this same story over and over.
The 'processification' of work, the algorithm of life seems to be simply a setting of the stage for the rise of the robot. You don't need to 'Google' for long to find that the world, including Google of course,  is robot-crazy... or to find a trillion pundits predicting a Terminator style rise of the robot. At present though we must be content with the fleshy  'white-collar-droids' we have ourselves have become.

In my profession, I observe teachers giving over and over again stereotyped state-approved lessons using masses of technology such as computers, VLEs, Interactive White Boards, PowerPoint and so on. They are mostly young intelligent decent people but are completely conditioned to accept constant assessment, observation and review from their handlers. It looks to me like the notion of beating the system has been bred out...it's not even challenged, not even by way of a 1984 'thought-crime'.

I'm not mixing the Brave New World of Huxley's and Orwell's dystopia but am struck by the realisation of their fables which are linked by the unbeatable system. With this often at the forefront of my mind I was really taken aback by a series of 'last episodes' of television dramas. These were no ordinary dramas but mega-watched big hitter crime thrillers. In order: 'The Killing' with knitwear hero Sarah Lund; 'Poirot' starring the ageing eponymous Hercule Poirot and finally 'Sherlock' with of course Sherlock.

All three have fictional heroes who are widely regarded as being highly intelligent, emotionally cold and, well, being a bit of a way along the socio-path path. Finally they come up against  individuals who have  manipulated their way to power and were 'system-wise' unbeatable.

What did Poirot, Lund and Holmes do? They murdered them. No pretence was made that they could be beaten through the system, no self serving escape of the consequence of their criminality. They just shot them.

The point I would like to make to anyone who is busy devising, elaborating, supervising or enforcing systems is that they (the systems) despite appearances are desperately fragile and that the odd looking naked-ape you see going about your business is a very dangerous primate.

If even our fictional super-brains can't beat the system and resort to murder what will become of us?

...well it's obvious we had better replace them with robots.. sharpish.