Tuesday, 20 October 2015
Darwinism Vs. the real world XVII
Blood Flow Requires a Complex, Well-Designed System
Howard Glicksman October 20, 2015 9:55 AM
Editor's note: Physicians have a special place among the thinkers who have elaborated the argument for intelligent design. Perhaps that's because, more than evolutionary biologists, they are familiar with the challenges of maintaining a functioning complex system, the human body. With that in mind, Evolution News & Views is delighted to present this series, "The Designed Body." For the complete series, see here. Dr. Glicksman practices palliative medicine for a hospice organization.
The cells that make up the organs and tissues of the body require the blood in the circulation to give them what they need so they can do what they need to do. The heart must pump enough blood with enough pressure behind it to maintain sufficient blood flow. Blood flow can be defined as the volume of blood that passes a given point in the circulation system within a given amount of time, and is usually measured in "milliliters per minute" (mL/min).
As I've shown in prior articles in this series, the laws of nature state that blood flow (Q) to a given organ is directly related to the pressure (P) of the blood as it enters its capillaries and inversely related to the vascular resistance (R) applied by its arterioles. This natural relationship can be expressed as Q = P/R. The higher the pressure, the more blood flow and the lower the pressure, the less blood flow. And the higher the vascular resistance, the less blood flow, and the lower the vascular resistance, the more blood flow.
Common sense tells us that the wider the passageway the easier the flow. Just consider rush hour traffic moving along a highway. The more lanes there are available, the more cars can move through in a given amount of time. Now think about what happens when the cars leave the highway. Compared to a single-lane exit ramp, a double-lane one provides much less resistance and allows easier flow off the highway. The blood hurtling through the smaller arteries, trying to enter the arterioles on the way to the tissues, is like cars in a crush of rush hour traffic trying to enter the various exit ramps to reach their destinations. The wider the opening in the arterioles, the more blood can flow through, and the narrower the opening, the less blood can flow through.
The arterioles can increase or decrease the amount of resistance they apply to the blood trying to enter an organ by increasing or decreasing the contraction of the muscle surrounding them. An increase in muscle contraction closes down the opening in the arteriole, making the passageway (lumen) smaller. This increases the resistance and lowers the blood flow. And a decrease in muscle contraction opens up the lumen, decreasing the resistance and increasing the blood flow. In fact, the laws of nature state that the change in blood flow is directly related to the fourth power of the change in the luminal diameter. This means that if the luminal diameter of the blood vessel doubles, the blood flow increases by a factor of sixteen, and if it halves it decreases by a factor of sixteen.
At rest, total blood flow within the systemic circulation (cardiac output) is about 5,000 mL/min (5 L/min). With high levels of activity, something our earliest ancestors would have had to do often, it rises to about 25L/min. However, just because the body can generate enough cardiac output to meet its metabolic needs doesn't mean that the increase in blood flow will automatically go to the organs and tissues that really need it. This requires the body to take control in order to follow the rules that nature throws at it. Real numbers have real consequences, and if with increased activity the body can't get enough blood flow to the heart and skeletal muscle while preserving it to the brain, the body cannot function. This is what the body of our earliest ancestors would have had to have been able to do to survive within the laws of nature, something that evolutionary biology has yet to even mention, never mind explain.
The blood flow to a given organ or tissue is dependent, not only on its mass, but also its energy needs, in other words, what it's doing. The brain of a 70 Kg man has a mass of only 1500 gm, about 2 percent of his total mass. But at rest, the brain receives 750 mL/min, or 15 percent of the cardiac output. The brain needs a high amount of blood flow, over and above what one would expect for its size, because even though the body may be at rest, the brain is always working hard. In fact, no matter how little or how much the body exerts itself, the amount of blood flow to the brain must stay at 750 mL/min for it to work properly. The heart, with a mass of only about 300 gm, less than 1 percent of the body's total, is another organ that must constantly work, even when the body is at rest. At rest, the heart receives about 250 mL/min of the cardiac output, or about 5 percent of the total blood flow.
In contrast, the skeletal muscle, with a mass of about 30 Kg, or 40 percent of the body's total, at rest receives only 15 percent of the cardiac output, or 750 mL/min. At rest, the remaining blood flow mostly goes to the liver and gastrointestinal system (25 percent), the kidneys (20 percent), the fat (5 percent), the bones (5 percent), the skin (5 percent), and the lungs (2.5 percent).
The muscles surrounding the arterioles respond to several different factors. Some of these are intrinsic to what is going on inside and around the arterioles. This includes the pressure the blood applies as it enters and stretches the arteriolar wall and the presence of certain chemicals related to the metabolism of the tissues. Other factors are extrinsic to the arterioles, which include various hormones released by glands and neurohormones released by nerve cells. At rest, the main extrinsic factor that affects local blood flow is the sympathetic nervous system.
Except for in the brain, the sympathetic neurohormone, norepinephrine, attaches to specific receptors on the muscles surrounding most of the arterioles in the body and tells them to stay contracted. The resulting vasoconstriction causes limited blood flow through most of the organs and tissues. At rest, particularly in the brain and the heart, the main intrinsic factor that affects blood flow is autoregulation, in which the arteriolar resistance is constantly adjusted to match the pressure of the entering blood to maintain a relatively constant blood flow.
When the body is very active, such as when our ancient ancestors were running to find food or trying to avoid becoming food, the cardiac output is about 25L/min. The majority of this quintupling of blood flow must go to the skeletal and heart muscle so the body can do what it needs to do to survive. In fact, compared to what it receives at rest, during extreme physical exertion, the amount of blood flow to the skeletal muscle increases 28-fold to about 21 L/min and the blood flow to the heart muscle more than quadruples, going from 250 mL/min at rest, to over 1,000 mL/min. The brain is able to maintain its usual blood flow of 750 mL/min, but most of the other organs and tissues of the body see a decrease in blood flow.
For example, the blood flow to the liver and gastrointestinal system drops about 60 percent, from 1.25 L/min to 500 mL/min and the blood flow to the kidneys drops 75 percent, from 1,000 mL/min to only 250 mL/min. Since the change in blood flow is directly related to the fourth power of the change in the luminal diameter this means that the luminal diameter of the arterioles supplying blood to the skeletal muscle must increase by 130 percent and those to the heart muscle by 40 percent. Those to the liver, the gastrointestinal system and the kidneys decrease by about 10 percent. So, how does the body know when to make these changes?
When the body becomes active the main intrinsic factor that affects local blood flow is something called metabolic or functional hyperemia. Increased muscle activity causes the local buildup of several different chemicals that make the muscles surrounding the local arterioles relax. This vasodilation reduces the vascular resistance and increases local blood flow. This is one of the main reasons why the blood flow to the skeletal and heart muscle increases with activity.
In addition, the main extrinsic factor that affects local blood flow with increased activity is an increase in the sympathetic response as well, but with an added twist. Except for the brain, an increase in norepinephrine usually makes the muscles surrounding the arterioles everywhere else in the body contract. This causes an increased vascular resistance and less blood flow. This explains why, with increased physical activity, the blood flow to most of the other organs and tissues is reduced. But with increased activity, more epinephrine is released as well. The muscles surrounding the arterioles that supply blood to the skeletal and heart muscle are unique in that they have specific receptors for epinephrine. Epinephrine stimulates these muscles to relax, reversing the effects of norepinephrine, which reduces the vascular resistance and increases the blood flow to the skeletal and heart muscle.
We have seen that to survive under the laws of nature, the body must follow the rules and take control by making sure that, when it comes to blood flow to specific organs and tissues, the numbers follow the Goldilocks principle and be "just right." Having all the parts in place to maintain this type of control requires, not only that the system be irreducibly complex, but also have a natural survival capacity to be able to do exactly what has to be done and at the right time. In fact, to do all of this the body must inherently know that Q = P/R and the change in Q is directly related to the fourth power of the change in the luminal diameter.
This completes our discussion of cardiovascular function and how the body makes sure that its trillions of cells get what they need to live, grow, and work properly. However, life is a dynamic process and our earliest ancestors would have had to have remained very active to win the battle for survival. The body does not live within the imaginations of evolutionary biologists but within the laws of nature in which battles involves injuries. Injury to blood vessels leads to bleeding, which if serious enough can be fatal. That's what we'll start to look at next time.
Howard Glicksman October 20, 2015 9:55 AM
Editor's note: Physicians have a special place among the thinkers who have elaborated the argument for intelligent design. Perhaps that's because, more than evolutionary biologists, they are familiar with the challenges of maintaining a functioning complex system, the human body. With that in mind, Evolution News & Views is delighted to present this series, "The Designed Body." For the complete series, see here. Dr. Glicksman practices palliative medicine for a hospice organization.
The cells that make up the organs and tissues of the body require the blood in the circulation to give them what they need so they can do what they need to do. The heart must pump enough blood with enough pressure behind it to maintain sufficient blood flow. Blood flow can be defined as the volume of blood that passes a given point in the circulation system within a given amount of time, and is usually measured in "milliliters per minute" (mL/min).
As I've shown in prior articles in this series, the laws of nature state that blood flow (Q) to a given organ is directly related to the pressure (P) of the blood as it enters its capillaries and inversely related to the vascular resistance (R) applied by its arterioles. This natural relationship can be expressed as Q = P/R. The higher the pressure, the more blood flow and the lower the pressure, the less blood flow. And the higher the vascular resistance, the less blood flow, and the lower the vascular resistance, the more blood flow.
Common sense tells us that the wider the passageway the easier the flow. Just consider rush hour traffic moving along a highway. The more lanes there are available, the more cars can move through in a given amount of time. Now think about what happens when the cars leave the highway. Compared to a single-lane exit ramp, a double-lane one provides much less resistance and allows easier flow off the highway. The blood hurtling through the smaller arteries, trying to enter the arterioles on the way to the tissues, is like cars in a crush of rush hour traffic trying to enter the various exit ramps to reach their destinations. The wider the opening in the arterioles, the more blood can flow through, and the narrower the opening, the less blood can flow through.
The arterioles can increase or decrease the amount of resistance they apply to the blood trying to enter an organ by increasing or decreasing the contraction of the muscle surrounding them. An increase in muscle contraction closes down the opening in the arteriole, making the passageway (lumen) smaller. This increases the resistance and lowers the blood flow. And a decrease in muscle contraction opens up the lumen, decreasing the resistance and increasing the blood flow. In fact, the laws of nature state that the change in blood flow is directly related to the fourth power of the change in the luminal diameter. This means that if the luminal diameter of the blood vessel doubles, the blood flow increases by a factor of sixteen, and if it halves it decreases by a factor of sixteen.
At rest, total blood flow within the systemic circulation (cardiac output) is about 5,000 mL/min (5 L/min). With high levels of activity, something our earliest ancestors would have had to do often, it rises to about 25L/min. However, just because the body can generate enough cardiac output to meet its metabolic needs doesn't mean that the increase in blood flow will automatically go to the organs and tissues that really need it. This requires the body to take control in order to follow the rules that nature throws at it. Real numbers have real consequences, and if with increased activity the body can't get enough blood flow to the heart and skeletal muscle while preserving it to the brain, the body cannot function. This is what the body of our earliest ancestors would have had to have been able to do to survive within the laws of nature, something that evolutionary biology has yet to even mention, never mind explain.
The blood flow to a given organ or tissue is dependent, not only on its mass, but also its energy needs, in other words, what it's doing. The brain of a 70 Kg man has a mass of only 1500 gm, about 2 percent of his total mass. But at rest, the brain receives 750 mL/min, or 15 percent of the cardiac output. The brain needs a high amount of blood flow, over and above what one would expect for its size, because even though the body may be at rest, the brain is always working hard. In fact, no matter how little or how much the body exerts itself, the amount of blood flow to the brain must stay at 750 mL/min for it to work properly. The heart, with a mass of only about 300 gm, less than 1 percent of the body's total, is another organ that must constantly work, even when the body is at rest. At rest, the heart receives about 250 mL/min of the cardiac output, or about 5 percent of the total blood flow.
In contrast, the skeletal muscle, with a mass of about 30 Kg, or 40 percent of the body's total, at rest receives only 15 percent of the cardiac output, or 750 mL/min. At rest, the remaining blood flow mostly goes to the liver and gastrointestinal system (25 percent), the kidneys (20 percent), the fat (5 percent), the bones (5 percent), the skin (5 percent), and the lungs (2.5 percent).
The muscles surrounding the arterioles respond to several different factors. Some of these are intrinsic to what is going on inside and around the arterioles. This includes the pressure the blood applies as it enters and stretches the arteriolar wall and the presence of certain chemicals related to the metabolism of the tissues. Other factors are extrinsic to the arterioles, which include various hormones released by glands and neurohormones released by nerve cells. At rest, the main extrinsic factor that affects local blood flow is the sympathetic nervous system.
Except for in the brain, the sympathetic neurohormone, norepinephrine, attaches to specific receptors on the muscles surrounding most of the arterioles in the body and tells them to stay contracted. The resulting vasoconstriction causes limited blood flow through most of the organs and tissues. At rest, particularly in the brain and the heart, the main intrinsic factor that affects blood flow is autoregulation, in which the arteriolar resistance is constantly adjusted to match the pressure of the entering blood to maintain a relatively constant blood flow.
When the body is very active, such as when our ancient ancestors were running to find food or trying to avoid becoming food, the cardiac output is about 25L/min. The majority of this quintupling of blood flow must go to the skeletal and heart muscle so the body can do what it needs to do to survive. In fact, compared to what it receives at rest, during extreme physical exertion, the amount of blood flow to the skeletal muscle increases 28-fold to about 21 L/min and the blood flow to the heart muscle more than quadruples, going from 250 mL/min at rest, to over 1,000 mL/min. The brain is able to maintain its usual blood flow of 750 mL/min, but most of the other organs and tissues of the body see a decrease in blood flow.
For example, the blood flow to the liver and gastrointestinal system drops about 60 percent, from 1.25 L/min to 500 mL/min and the blood flow to the kidneys drops 75 percent, from 1,000 mL/min to only 250 mL/min. Since the change in blood flow is directly related to the fourth power of the change in the luminal diameter this means that the luminal diameter of the arterioles supplying blood to the skeletal muscle must increase by 130 percent and those to the heart muscle by 40 percent. Those to the liver, the gastrointestinal system and the kidneys decrease by about 10 percent. So, how does the body know when to make these changes?
When the body becomes active the main intrinsic factor that affects local blood flow is something called metabolic or functional hyperemia. Increased muscle activity causes the local buildup of several different chemicals that make the muscles surrounding the local arterioles relax. This vasodilation reduces the vascular resistance and increases local blood flow. This is one of the main reasons why the blood flow to the skeletal and heart muscle increases with activity.
In addition, the main extrinsic factor that affects local blood flow with increased activity is an increase in the sympathetic response as well, but with an added twist. Except for the brain, an increase in norepinephrine usually makes the muscles surrounding the arterioles everywhere else in the body contract. This causes an increased vascular resistance and less blood flow. This explains why, with increased physical activity, the blood flow to most of the other organs and tissues is reduced. But with increased activity, more epinephrine is released as well. The muscles surrounding the arterioles that supply blood to the skeletal and heart muscle are unique in that they have specific receptors for epinephrine. Epinephrine stimulates these muscles to relax, reversing the effects of norepinephrine, which reduces the vascular resistance and increases the blood flow to the skeletal and heart muscle.
We have seen that to survive under the laws of nature, the body must follow the rules and take control by making sure that, when it comes to blood flow to specific organs and tissues, the numbers follow the Goldilocks principle and be "just right." Having all the parts in place to maintain this type of control requires, not only that the system be irreducibly complex, but also have a natural survival capacity to be able to do exactly what has to be done and at the right time. In fact, to do all of this the body must inherently know that Q = P/R and the change in Q is directly related to the fourth power of the change in the luminal diameter.
This completes our discussion of cardiovascular function and how the body makes sure that its trillions of cells get what they need to live, grow, and work properly. However, life is a dynamic process and our earliest ancestors would have had to have remained very active to win the battle for survival. The body does not live within the imaginations of evolutionary biologists but within the laws of nature in which battles involves injuries. Injury to blood vessels leads to bleeding, which if serious enough can be fatal. That's what we'll start to look at next time.
The Tartarus of the bible:The Watchtower Society's commentary.
TARTARUS:
A prisonlike, abased condition into which God cast disobedient angels in Noah’s day.
This word is found but once in the inspired Scriptures, at 2 Peter 2:4. The apostle writes: “God did not hold back from punishing the angels that sinned, but, by throwing them into Tartarus, delivered them to pits of dense darkness to be reserved for judgment.” The expression “throwing them into Tartarus” is from the Greek verb tar·ta·roʹo and so includes within itself the word “Tartarus.”
A parallel text is found at Jude 6: “And the angels that did not keep their original position but forsook their own proper dwelling place he has reserved with eternal bonds under dense darkness for the judgment of the great day.” Showing when it was that these angels “forsook their own proper dwelling place,” Peter speaks of “the spirits in prison, who had once been disobedient when the patience of God was waiting in Noah’s days, while the ark was being constructed.” (1Pe 3:19, 20) This directly links the matter to the account at Genesis 6:1-4 concerning “the sons of the true God” who abandoned their heavenly abode to cohabit with women in pre-Flood times and produced children by them, such offspring being designated as Nephilim.—See NEPHILIM; SON(S) OF GOD.
From these texts it is evident that Tartarus is a condition rather than a particular location, inasmuch as Peter, on the one hand, speaks of these disobedient spirits as being in “pits of dense darkness,” while Paul speaks of them as being in “heavenly places” from which they exercise a rule of darkness as wicked spirit forces. (2Pe 2:4; Eph 6:10-12) The dense darkness similarly is not literally a lack of light but results from their being cut off from illumination by God as renegades and outcasts from his family, with only a dark outlook as to their eternal destiny.
Tartarus is, therefore, not the same as the Hebrew Sheol or the Greek Hades, both of which refer to the common earthly grave of mankind. This is evident from the fact that, while the apostle Peter shows that Jesus Christ preached to these “spirits in prison,” he also shows that Jesus did so, not during the three days while buried in Hades (Sheol), but after his resurrection out of Hades.—1Pe 3:18-20.
Likewise the abased condition represented by Tartarus should not be confused with “the abyss” into which Satan and his demons are eventually to be cast for the thousand years of Christ’s rule. (Re 20:1-3) Apparently the disobedient angels were cast into Tartarus in “Noah’s days” (1Pe 3:20), but some 2,000 years later we find them entreating Jesus “not to order them to go away into the abyss.”—Lu 8:26-31; see ABYSS.
The word “Tartarus” is also used in pre-Christian heathen mythologies. In Homer’s Iliad this mythological Tartarus is represented as an underground prison ‘as far below Hades as earth is below heaven.’ In it were imprisoned the lesser gods, Cronus and the other Titan spirits. As we have seen, the Tartarus of the Bible is not a place but a condition and, therefore, is not the same as this Tartarus of Greek mythology. However, it is worth noting that the mythological Tartarus was presented not as a place for humans but as a place for superhuman creatures. So, in that regard there is a similarity, since the Scriptural Tartarus is clearly not for the detention of human souls (compare Mt 11:23) but is only for wicked superhuman spirits who are rebels against God.
The condition of utter debasement represented by Tartarus is a precursor of the abyssing that Satan and his demons are to experience prior to the start of the Thousand Year Reign of Christ. This, in turn, is to be followed after the end of the thousand years by their utter destruction in “the second death.”—Mt 25:41; Re 20:1-3, 7-10, 14.
A prisonlike, abased condition into which God cast disobedient angels in Noah’s day.
This word is found but once in the inspired Scriptures, at 2 Peter 2:4. The apostle writes: “God did not hold back from punishing the angels that sinned, but, by throwing them into Tartarus, delivered them to pits of dense darkness to be reserved for judgment.” The expression “throwing them into Tartarus” is from the Greek verb tar·ta·roʹo and so includes within itself the word “Tartarus.”
A parallel text is found at Jude 6: “And the angels that did not keep their original position but forsook their own proper dwelling place he has reserved with eternal bonds under dense darkness for the judgment of the great day.” Showing when it was that these angels “forsook their own proper dwelling place,” Peter speaks of “the spirits in prison, who had once been disobedient when the patience of God was waiting in Noah’s days, while the ark was being constructed.” (1Pe 3:19, 20) This directly links the matter to the account at Genesis 6:1-4 concerning “the sons of the true God” who abandoned their heavenly abode to cohabit with women in pre-Flood times and produced children by them, such offspring being designated as Nephilim.—See NEPHILIM; SON(S) OF GOD.
From these texts it is evident that Tartarus is a condition rather than a particular location, inasmuch as Peter, on the one hand, speaks of these disobedient spirits as being in “pits of dense darkness,” while Paul speaks of them as being in “heavenly places” from which they exercise a rule of darkness as wicked spirit forces. (2Pe 2:4; Eph 6:10-12) The dense darkness similarly is not literally a lack of light but results from their being cut off from illumination by God as renegades and outcasts from his family, with only a dark outlook as to their eternal destiny.
Tartarus is, therefore, not the same as the Hebrew Sheol or the Greek Hades, both of which refer to the common earthly grave of mankind. This is evident from the fact that, while the apostle Peter shows that Jesus Christ preached to these “spirits in prison,” he also shows that Jesus did so, not during the three days while buried in Hades (Sheol), but after his resurrection out of Hades.—1Pe 3:18-20.
Likewise the abased condition represented by Tartarus should not be confused with “the abyss” into which Satan and his demons are eventually to be cast for the thousand years of Christ’s rule. (Re 20:1-3) Apparently the disobedient angels were cast into Tartarus in “Noah’s days” (1Pe 3:20), but some 2,000 years later we find them entreating Jesus “not to order them to go away into the abyss.”—Lu 8:26-31; see ABYSS.
The word “Tartarus” is also used in pre-Christian heathen mythologies. In Homer’s Iliad this mythological Tartarus is represented as an underground prison ‘as far below Hades as earth is below heaven.’ In it were imprisoned the lesser gods, Cronus and the other Titan spirits. As we have seen, the Tartarus of the Bible is not a place but a condition and, therefore, is not the same as this Tartarus of Greek mythology. However, it is worth noting that the mythological Tartarus was presented not as a place for humans but as a place for superhuman creatures. So, in that regard there is a similarity, since the Scriptural Tartarus is clearly not for the detention of human souls (compare Mt 11:23) but is only for wicked superhuman spirits who are rebels against God.
The condition of utter debasement represented by Tartarus is a precursor of the abyssing that Satan and his demons are to experience prior to the start of the Thousand Year Reign of Christ. This, in turn, is to be followed after the end of the thousand years by their utter destruction in “the second death.”—Mt 25:41; Re 20:1-3, 7-10, 14.
It's design all the way Down VI
Please bear in mind that we are talking about proto life here the very oldest lifeforms on the planet.
Biologists discover electric bacteria that eat pure electrons rather than sugar, redefining the tenacity of life
By Sebastian Anthony on July 18, 2014 at 8:51 am
Some intrepid biologists at the University of Southern California (USC) have discovered bacteria that survives on nothing but electricity — rather than food, they eat and excrete pure electrons. These bacteria yet again prove the almost miraculous tenacity of life — but, from a technology standpoint, they might also prove to be useful in enabling the creation of self-powered nanoscale devices that clean up pollution. Some of these bacteria also have the curious ability to form into ‘biocables,’ microbial nanowires that are centimeters long and conduct electricity as well as copper wires — a capability that might one day be tapped to build long, self-assembling subsurface networks for human use.
As you may recall from high school biology, almost every living organism consumes sugar to survive. When it gets right down to it, everything you eat is ultimately converted or digested into single molecules of glucose. Without going into the complexities of respiration and metabolism (ATP!), these sugars have excess electrons — and the oxygen you breathe in really wants those electrons. By ferrying electrons from sugar to oxygen, a flow of electrons — i.e. energy — is created, which is then used to carry out various vital tasks around your body (triggering electrons, beating your heart, etc.)These special bacteria, however, don’t need no poxy sugars — instead, they cut out the middleman and feed directly on electrons. To discover these bacteria, and to cultivate them in the lab, the USC biologists quite simply scooped up some sediment from the ocean, took it back to the lab, stuck some electrodes into it, and then turned on the power. When higher voltages are pumped into the water, the bacteria “eats” electrons from the electrode; when a lower voltage is present, the bacteria “exhales” electrons onto the electrode, creating an electrical current (which could be used to power a device, if you were so inclined). The USC study very carefully controlled for other sources of nutrition — these bacteria were definitely eating electrons directly.
All told, various researchers around the world have now discovered upwards of 10 different kinds of bacteria that feed on electricity — and, interestingly, they’re all pretty different (they’re not from the same family), and none of them are like Shewanella or Geobacter, two well-known bacteria that have interesting electrical properties. Kenneth Nealson of USC, speaking to New Scientist about his team’s discovery, said: “This is huge. What it means is that there’s a whole part of the microbial world that we don’t know about.”
As for the repercussions of finding bacteria that eat and excrete electrons, the most obvious use is in the growing fields of molecular motors and nanomachines. These bacteria, at their most basic, are machines that consume raw electricity — and so, with some clever (genetic?) engineering, it stands to reason that we might one day use them to power tiny machines that can perform tasks that are currently carried out by expensive, human-operated machines (cleaning up chemical spills, for example). These bacteria might also allow us to find out exactly how much energy a living cell needs to survive; put them in a test tube, and then slowly dial back the electrode voltage until they die. A cruel experiment, but one that would yield very informative results.
In a separate study a few years ago, researchers at Aarhus University in Denmark found that some electric bacteria also have the ability to form microbial nanowires — long chains of bacteria that can span several centimeters. These nanowires ferry nutrients to bacteria further down the chain, which might be stuck underneath some mud. Curiously, these nanowires are about as conductive as standard copper wires, which leads us to wonder if electric bacteria might one day be coerced into building subsurface networks for human use. It would be a little more efficient than spending billions of dollars on laying submarine cables…
Biologists discover electric bacteria that eat pure electrons rather than sugar, redefining the tenacity of life
By Sebastian Anthony on July 18, 2014 at 8:51 am
Some intrepid biologists at the University of Southern California (USC) have discovered bacteria that survives on nothing but electricity — rather than food, they eat and excrete pure electrons. These bacteria yet again prove the almost miraculous tenacity of life — but, from a technology standpoint, they might also prove to be useful in enabling the creation of self-powered nanoscale devices that clean up pollution. Some of these bacteria also have the curious ability to form into ‘biocables,’ microbial nanowires that are centimeters long and conduct electricity as well as copper wires — a capability that might one day be tapped to build long, self-assembling subsurface networks for human use.
As you may recall from high school biology, almost every living organism consumes sugar to survive. When it gets right down to it, everything you eat is ultimately converted or digested into single molecules of glucose. Without going into the complexities of respiration and metabolism (ATP!), these sugars have excess electrons — and the oxygen you breathe in really wants those electrons. By ferrying electrons from sugar to oxygen, a flow of electrons — i.e. energy — is created, which is then used to carry out various vital tasks around your body (triggering electrons, beating your heart, etc.)These special bacteria, however, don’t need no poxy sugars — instead, they cut out the middleman and feed directly on electrons. To discover these bacteria, and to cultivate them in the lab, the USC biologists quite simply scooped up some sediment from the ocean, took it back to the lab, stuck some electrodes into it, and then turned on the power. When higher voltages are pumped into the water, the bacteria “eats” electrons from the electrode; when a lower voltage is present, the bacteria “exhales” electrons onto the electrode, creating an electrical current (which could be used to power a device, if you were so inclined). The USC study very carefully controlled for other sources of nutrition — these bacteria were definitely eating electrons directly.
All told, various researchers around the world have now discovered upwards of 10 different kinds of bacteria that feed on electricity — and, interestingly, they’re all pretty different (they’re not from the same family), and none of them are like Shewanella or Geobacter, two well-known bacteria that have interesting electrical properties. Kenneth Nealson of USC, speaking to New Scientist about his team’s discovery, said: “This is huge. What it means is that there’s a whole part of the microbial world that we don’t know about.”
As for the repercussions of finding bacteria that eat and excrete electrons, the most obvious use is in the growing fields of molecular motors and nanomachines. These bacteria, at their most basic, are machines that consume raw electricity — and so, with some clever (genetic?) engineering, it stands to reason that we might one day use them to power tiny machines that can perform tasks that are currently carried out by expensive, human-operated machines (cleaning up chemical spills, for example). These bacteria might also allow us to find out exactly how much energy a living cell needs to survive; put them in a test tube, and then slowly dial back the electrode voltage until they die. A cruel experiment, but one that would yield very informative results.
In a separate study a few years ago, researchers at Aarhus University in Denmark found that some electric bacteria also have the ability to form microbial nanowires — long chains of bacteria that can span several centimeters. These nanowires ferry nutrients to bacteria further down the chain, which might be stuck underneath some mud. Curiously, these nanowires are about as conductive as standard copper wires, which leads us to wonder if electric bacteria might one day be coerced into building subsurface networks for human use. It would be a little more efficient than spending billions of dollars on laying submarine cables…
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