The "interconnectedness of all things" is a notion embraced by the spiritual community and, more recently, by science in the field of quantum mechanics.
This area of research is still regarded as largely theoretical by the scientific community, however, unlike the "nuts and bolts" science that focuses on improving our medical and technological knowledge with solid, peer-reviewed studies.
Yet a recent finding made by UCSF scientists seems to a have distinctly quantum flavor to it: in a discovery that directly contradicts the standard biological model of animal cell communication, researchers discovered that typical cells in animals have the ability to transmit and receive biological signals by making physical contact with each other, even at long distance. The mechanism appears to be similar to the way neurons communicate with other cells, and contrasts the standard understanding that non-neuronal cells "basically spit out signaling proteins into extracellular fluid and hope they find the right target," explained senior investigator Thomas B. Kornberg, PhD, a professor of biochemistry with the UCSF Cardiovascular Research Institute.
In the study, the results of which was published earlier this year in the journal Science, living tissue from fruit flies was used to demonstrate that cells send out long, thin tubes of cytoplasm called cytonemes, which Kornberg said "can extend across the length of 50 or 100 cells" before touching the cells they are targeting. The point of contact between a cytoneme and its target cell acts as a communications bridge between the two cells.
"It’s long been known that neurons communicate in a similar way, by transferring signals at points of contact called synapses, and transmitting the response over long distances in long tubes called axons," said Kornberg. "However, it’s always been thought that this mode of signaling was unique to neurons. We have now shown that many types of animal cells have the same ability to reach out and synapse with one another in order to communicate, using signaling proteins as units of information instead of the neurotransmitters and electrical impulses that neurons use."
In fact, said Kornberg, "I would argue that the only strong experimental data that exists today for a mechanism by which these signaling proteins move from one cell to another is at these points of contact and via cytonemes."
However, he noted, "There are 100 years worth of work and thousands of scientific papers in which it has been simply assumed that these proteins move from one cell to another by moving through extracellular fluid. So this is a fundamentally different way of considering how signaling goes on in tissues."
The scientists found that the sites of contact possessed the characteristics of synapses formed by neurons. They demonstrated that in flies that had been genetically engineered to lack synapse-making proteins, cells are unable to form synapses or signal successfully.
"In the mutants, the signals that are normally taken up by target cells are not taken up, and signaling is prevented," said Kornberg. "This demonstrates that physical contact is required for signal transfer, signal uptake and signaling."
This type of highly intricate research has not previously been possible, as animal cells structures are so fragile that they have been unable to survive traditional laboratory imaging methods. Kornberg described how recent developments have made the experiments possible:
"During the last decade or so, though, there have been fantastic technical advances, including new techniques in genetic engineering, new microscopes that improve the resolution and sensitivity for imaging living cells and the development of fluorescent marker proteins that we can attach to proteins of interest."
Using these new technologies, Kornberg and his team have captured vivid images, and even movies, of fluorescent signaling proteins moving through fluorescently marked cytonemes.
"We are not saying that cells always use cytonemes for signaling," Kornberg cautioned. "Hormones, for example, are another method of long distance cell signaling. A cell that takes up insulin does not care where that insulin came from — a pancreas or an intravenous injection. But there are signals of a specialized type, such as those that pass between stem cells and the cells around them, or signals that determine tissue growth, patterning and function, where the identity of the communicating cells must be precisely defined. It’s important that these signals are received in the context of the cells that are making them."
So could this discovery herald the birth of a new field of research, as scientists discover that a form of "quantum biology" exists within the incredibly complex physiology of all living things?
Certainly the discovery of animal cell cytonemes and the critical role they play in long distance signaling "opens up a wonderful biology of which we have very little understanding at this point," said Kornberg. "For example, how do these cytonemes find their targets? How do they know when they have found them? These are some of the questions that we are pursuing."
Despite its perception as an inherently organic, living field of research, there exists on the fringes a growing new field of "quantum biology" where the weird – and sometimes still unexplained – behavior of plants and animals is being explored in more detail.
Luca Turin of the Fleming Institute in Greece explained that at least three areas of biology have turned out to fall squarely in the quantum camp:
"There are definitely three areas that have turned out to be manifestly quantum," Dr Turin told the BBC. "These three things… have dispelled the idea that quantum mechanics had nothing to say about biology."
Though studied by most children in basic biology lessons, photosynthesis – the process by which plants and some bacteria utilise the energy from sunlight for growth – appears to require a quantum "superposition" technique.
The term "superposition" describes the situation where a particle exists in a number of possible states or locations simultaneously; for example, an electron might be in your hand but also in the furthest corner of the Universe at the same time. It is only when the particle is observed that it selects to exist in one particular state. In photosynthesis, this seems to occur when units of energy simultaneously attempt all possible paths to arrive at their destination, and then decide on the most efficient.
"Biology seems to have been able to use these subtle effects in a warm, wet environment and still maintain the [superposition]. How it does that we don’t understand," Richard Cogdell of the University of Glasgow told the BBC.
The second area of quantum biology to be identified is "entanglement." In quantum mechanics, this describes two particles that have become entangled so that their properties depend on each other, no matter how far apart they get, meaning that measurements of one will affect the measurement of the other instantaneously.
In biology, studies revelealed that European robins only oriented themselves for migration under certain colours of light, and that very weak radio waves could completely mix up their sense of direction. This fact appeared to undermine the previous theory that birds possessed a standard compass in their cells to assist with navigation. Now quantum entanglement is being proposed as a more likely explanation.
Experiments suggest occurs within single molecules in birds’ eyes, but John Morton of University College London explained that the way birds sense it could be stranger still.
"You could think about that as… a kind of ‘heads-up display’ like what pilots have: an image of the magnetic field… imprinted on top of the image that they see around them," he said.
The third quantum state identified at work in living things is "Tunnelling," when particle breaks through an energy barrier, apparently disappearing on one side of it and reappearing on the other.
This process takes place in an unlikely place according to Dr. Turin, who explained that our noses may operate on a quantum level. He believes that electrons in the receptors in our noses disappear on one side of a smell molecule and reappear on the other, leaving a little bit of energy behind in the process.
The idea seems fantastic, yet Dr. Turin believes that biology has more magic to reveal.
"Are these three fields the tip of the iceberg, or is there actually no iceberg underneath?" asked Dr Turin. "We just don’t know. And we won’t know until we go and look."
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