快猫短视频

MASAKI KOBAYASHI is looking for the inner light in all of us. A physicist at
the Tohoku Institute of Technology in Sendai, Kobayashi is one of a small number
of researchers around the globe who spend hours locked in darkened labs in the
hope of glimpsing the faint glow that comes from all living tissue.

This glow is so elusive that we can only see it with the aid of the most
sensitive detectors. But we鈥檙e not talking about psychic auras here. These faint
throbs of light are probably little more than a by-product of the cell鈥檚 own
metabolism鈥攖he pint-sized equivalent of a spluttering car exhaust.

Yet researchers hope that one day differences in the light from healthy and
cancerous cells will give doctors a new non-invasive tool for spotting disease.
Others go further. They think that cells may coordinate their activities via
patterns of photons. A few even dare to suggest that these photons may actually
mediate consciousness itself.

Living creatures can undoubtedly emit light: around 80 per cent of marine
creatures, for example, fireflies and quite a few fungi and centipedes use
bioluminescence as their calling card. Generating this light usually involves a
chemical reaction between ATP鈥攖he cell鈥檚 energy store鈥攐xygen and a
molecule called luciferin. Luciferin converts the chemical energy locked up in
ATP into photons of light
(快猫短视频, 22 July 2000, p 34).
In most cases these cells produce a weak flash that is just visible to the human
eye.

But the kind of light that Kobayashi is interested in is far weaker鈥攊t
is typically several million times as faint as the light from a firefly. In
fact, the trickle of 鈥渂iophotons鈥� is so weak that researchers are only now
beginning to agree where it comes from.

The main source is free radicals: atoms or molecules with an unbound electron
that are desperate to pair up with electrons from other molecules. Free radicals
are often an unwelcome by-product of the reactions that take place at the inner
membrane of mitochondria鈥攖he power houses of the cell that use oxygen to
make the cell鈥檚 fuel ATP.

Free radicals are seriously bad news. When they bump into other molecules in
the cell such as proteins, lipids or sugars, they destroy them by slicing them
up into small chunks.

Most biological reactions take place in several small steps, each one
designed to use energy efficiently. But these free radical reactions are so
energetic that they tend to occur in one huge step. This means not all the
energy is used up in the reaction. A little is absorbed by an electron on the
molecule that鈥檚 under attack. This electron becomes unstable and sheds its extra
energy as a photon of light.

Since enzymes and anti-oxidants usually mop up reactive oxygen molecules and
free radicals before they can damage the cell, a healthy cell tends to release
very few photons, maybe only tens per minute. Not easy to collect, even in a
pitch-black lab.

This is one of the reasons the phenomenon has been so difficult to study. In
the 1970s, biochemists first considered biophotons as a way of studying reactive
oxygen molecules. 鈥淗owever biophoton emission is so weak and the mechanisms of
production are so complex, most biochemists were put off,鈥� Kobayashi says. For
example, veteran biophysicist Britton Chance at the University of Pennsylvania,
Philadelphia, showed that light was coming from free radicals created in
isolated mitochondria. 鈥淏ut detailed studies failed to detect a signal in dog鈥檚
brain,鈥� he says.

Things got a little easier in the 1980s when manufacturers such as Hamamatsu,
a Japanese company specialising in light detectors called photomultipliers,
developed new highly sensitive instruments designed to record weak light
signals. Keen to exploit this opportunity, and to seed a new bio-optics
industry, the Japanese government funded a five-year, multibillion-yen research
programme into biophotons in 1986. Humio Inaba, an engineer at the Research
Institute of Electrical Communication at Tohoku University headed the
project.

Dozens of researchers across Japan, including Kobayashi, found these
emissions coming out of everything from plant seeds to fruit flies. Inaba also
discovered that injured or stressed cells release far more photons than their
healthy counterparts. In particular, adzuki and soybean seedlings damaged with
cross-shaped cuts emit high levels of photons at the site of the injury.

Other teams have spotted increased levels of biophotons where cells are
damaged. Ken Muldrew, a biophysicist at the University of Calgary in Alberta,
Canada, tore tree leaves apart near his sensitive measuring equipment: 鈥淲e got
an enormous peak of tens of thousands of photons, a burst of light,鈥� says
Muldrew. 鈥淎 leaf screams when you tear it, but you see the scream instead of
hear it.鈥�

It isn鈥檛 just plant cells. At the Institute of Physics at the University of
Catania in Italy, isolated mammalian tumour cells ejected photons at rates as
high as 1400 per square centimetre per minute鈥攈ealthy tissues average
rates of less than 40. In a study on bladder cancer, Kobayashi鈥檚 team found that
the light intensity of tumour cells is 4 times as high as the surrounding
healthy tissue.

Clearly when cells are stressed or damaged, they pump out free
radicals鈥攁nd this produces light. But can doctors use these distress
flares as warnings of disease or illness? Almost certainly, says Reiner Vogel, a
biophysicist at the University of Freiburg in Germany. 鈥淭he emission may give a
very sensitive indication of the conditions within a cell and on the functioning
of the cellular defence mechanism,鈥� he says. Philip Coleridge Smith, a surgeon
at University College Medical School in London, agrees. You could perhaps use
biophotons to assess inflammation in tissues, he suggests, which might warn of
leg ulcers, for example.

To make a diagnosis what we need now is a sensitive detector and analysis
system, preferably non-invasive, that will measure an emission and even identify
its origins鈥攑erhaps from the spectrum or statistical properties of the
photons, Kobayashi says. He鈥檚 trying to find out if you can use photons to spot
disease in people, rather than in cells in a lab, and is developing ways to
convert patterns of photon emissions into images of the body that resemble
X-rays or CAT scans.

Turn to the light

Yet some believe that biophotons are far more than just distress signals. In
the early 1990s, Guenter Albrecht-Buehler, a biophysicist at Northwestern
University Medical School in Chicago, discovered that some cells can detect and
respond to light from others.

He shone infrared light onto a mixture of cell-sized latex beads and mouse
fibroblast cells. Many of the cells began to stretch out their arm-like
pseudopodia for light scattered towards them by the beads, and soon these cells
were heading directly for the beads. Some even turned 180掳 to reach them.
(With little power and a wavelength of around 850 nanometres, the light created
virtually no heat, so the cells weren鈥檛 simply moving towards warmth, argues
Albrecht-Buehler.) And since some cells reached out to two different light
sources of equal intensities at the same time, it seems that they could 鈥渟ee鈥�
each source distinctly, he suggests.

In other experiments, Albrecht-Buehler spread hamster cells on both sides of
a sheet of glass. As the cells grew, he found that those on one side shifted
around until they lay at angles of more than 45掳 to those on the other side
of the glass. But when he added a filter layer to the glass that blocked
infrared light transmission from one side to the other, the cells grew in random
directions (快猫短视频, 7 November 1992, p 14).

Tissues favour a criss-cross arrangement of cells because it gives them extra
strength, so perhaps the cells on the glass were using light to signal their
orientation. If so, they must have some kind of eye. Albrecht-Buehler thinks the
cell鈥檚 centrioles fit the bill. These cylindrical structures have slanted
鈥渂lades鈥� which he believes act as simple blinds. By only allowing light into the
centriole from certain angles, the blinds enable simple photoreceptors inside
the centrioles such as haem molecules to tell which direction photons are coming
from. And microtubules鈥攈ollow filaments that thread through
cells鈥攃ould act as optical fibres, he believes, feeding light towards the
centrioles from the cell鈥檚 wall.

But why should cells want to detect light? The most obvious answer is that
they are talking to each other, says Albrecht-Buehler. Cells in embryos might
signal with photons so that they know how and where they fit into the developing
body.

And now he wants to learn their language. He envisages doctors telling cells
what they want them to do in words they understand. You might tell cancer cells
to stop growing or encourage cells near wounds to start again. 鈥淲e may learn to
compose our own messages in the language of cells to compel them to carry out
specialised tasks that they鈥檝e never performed.鈥�

Albrecht-Beuhler isn鈥檛 the first to make this controversial claim. In the
1980s Fritz-Albert Popp, then a lecturer at the University of Marburg in
Germany, became interested in the optical behaviour of cells. In a series of
experiments Popp found that two cells separated by an opaque barrier release
biophotons in uncoordinated patterns. Remove the barrier and the cells soon
begin releasing photons in synchrony. The cells, Popp concluded, were
communicating by light.

Cyril Frank, professor of surgery at the University of Calgary鈥檚 medical
school believes Popp could be right. A photon could trigger events in the
receiving cell, making it change its rate of division or express different
proteins, he suggests. 鈥淚n our experiments, we鈥檙e trying to find out if these
sorts of triggers can do things like that.鈥� Although not ready to disclose any
data, he says they鈥檙e 鈥済etting some encouraging results鈥�.

Keep it simple

But Muldrew feels biophotons can only communicate simple messages. 鈥淲hat
biophotons communicate is the fact that certain oxidative reactions are going
辞苍.鈥�

It鈥檚 hard to know whether glowing cells will ever shed light on disease, help
scientists to work out the language of cells or even whether biophotons play a
role in consciousness (see 鈥淚nner Light鈥�). Cells are simply far too sensitive to
factors that alter the rate at which photons are emitted. 鈥淭he problem is
reproducibility of results, even for relatively simple systems like cell
cultures,鈥� says Barbara Chwirot, head of the Laboratory of Molecular Biology of
Cancer at Nicolas Copernicus University in Torun, Poland. Light emission may
depend on free radicals, but it is also affected by enzyme activity and the
supply of protective antioxidants such as vitamin E or carotenoids. 鈥淒irect
diagnosis of disease will remain difficult without some technical or medical
breakthrough,鈥� says Kobayashi.

For now the focus is on more prosaic pursuits. Popp, who now heads the
International Institute of Biophysics in Neuss, Germany, an association of
scientists interested in biophoton research, runs a company called Biophotonen
that offers its expertise in reading photon emissions to gauge the freshness and
purity of food. One of its first projects is with German brewer Bitburger, the
idea being to spot the glow from harmful bacteria before they can get into its
beer. A Chinese research group in Beijing is also perfecting a photon-based test
for the presence of microbes that could be used in the food industry.

But one day soon, bugs may not be the only things under the lens. Kobayashi
hopes that a new generation of detectors, such as avalanche photodiodes that
boost the chances of detecting individual photons from around 20 per cent up to
80 per cent or more, could provide the breakthrough he needs to develop a
scanner to diagnose disease. It might take 10 or 20 years, Kobayashi says, but
at last he thinks he can see light at the end of the tunnel.

Some maverick theorists suggest that the notion of a common cellular language
puts biophotons at the centre not only of biological communication, but also of
consciousness. Scott Hagan, a theoretical physicist at the British Columbia
Institute of Technology in Burnaby, has been pondering the enigmas of awareness
since he shared an office in grad school with a neurophysiologist. 鈥淚n every
other process, every atom or molecule does its own thing,鈥� he says. However, we
cannot think unless cells in the brain function simultaneously, as parts of a
whole. There鈥檚 no way that classical physics can explain this, he says. 鈥淏ut in
quantum physics, there are systems that know they鈥檙e wholes. These are called
quantum coherent states.鈥� These are states in which the wave functions of atoms
or molecules blend to form one single unit (快猫短视频, 24 March
2001, p 42). And the search for quantum coherent states in the brain leads
inside individual neurons, says Hagan, to their skeleton-like framework of
microtubules. These thin tubes are thought to move energy about the cell, help
build junctions between neurons and maintain memory. And anaesthetics work by
binding to them, says Hagan. 鈥淏ecause anaesthetics make consciousness evaporate,
their site of action is important in determining the mechanisms responsible for
consciousness,鈥� Hagan says. In a highly speculative theory, Hagan and Stuart
Hameroff, associate director of the Center for Consciousness Studies at the
University of Arizona, suggest that quantum coherence in the protein subunits of
microtubules may give rise to consciousness (快猫短视频, 20 August
1994, p 35). And, says Hameroff, biophotons could somehow control this
process.