Solar salamander

[Ray Moscow]

This is amazing:

A solar salamander
Photosynthetic algae have been found inside the cells of a vertebrate for the first time.

Such a close co-existence with a photosynthetic organism has previously been found in invertebrates, such as corals, but never in a vertebrate.

Because vertebrate cells have what is known as an adaptive immune system — which destroys biological material not considered 'self' — it was thought to be impossible for a symbiont to live stably inside them. But, in this case, the salamander cells have either turned their internal immune system off, or the algae have somehow bypassed it.

"On a lark, I decided to take a long-exposure fluorescent image of a pre-hatchling salamander embryo," says Kerney. When this revealed widely scattered dots of unstained cells fluorescing in the background — an indicator that those cells might contain chlorophyll — Kerney switched to transmission electron microscopy (TEM) to take a closer look.

"The surrounding salamander cells that contain the algae often have several mitochrondria bordering the algal symbiont," Kerney says, pointing to a TEM image.

Mitochondria are the powerhouses of animal cells, converting oxygen and a metabolic product of glucose into ATP, a molecule that cells use to store chemical energy. So salamander mitochondria gathered around an algal cell might be there to take advantage of the oxygen and carbohydrate generated by photosynthesis in that particular cell.

h/t to Matty

[DMB]

Fascinating!

[anthrosciguy]

That raises an interesting sci-fi-ish scenario for solving our food problems in the future: photosythesizing abilities in humans.

[Osteus Head]

Originally Posted by anthrosciguy

That raises an interesting sci-fi-ish scenario for solving our food problems in the future: photosythesizing abilities in humans.

Iv read that supressing the immune system in mamals allows the genes that control regeneration, like that which are active in amphibians, to be more easily expressed. Instead of scaring you get regeneration of the tissue. So you never know...

[premjan]

Photosynthesis doesn't provide enough energy for a normally active human. Even the brain consumes 100W I believe.

[Notta]

Originally Posted by anthrosciguy

That raises an interesting sci-fi-ish scenario for solving our food problems in the future: photosythesizing abilities in humans.

Or photosynthesizing abilities in chickens or other meat animals, requiring much less feeding.

Insert the cholorphyll gene into the genome to replace melanin, and you'd have a green animal that could photosynthesize through its skin.

Although humans with green hair, eyes, and freckles would look awesome!

[espritch]

Originally Posted by Notta

Or photosynthesizing abilities in chickens or other meat animals, requiring much less feeding.

Insert the cholorphyll gene into the genome to replace melanin, and you'd have a green animal that could photosynthesize through its skin.

Although humans with green hair, eyes, and freckles would look awesome!

I fondly remember drives through the country, watching the green cows munch the green grass.

Actually, I suspect removing melanin would have negative consequences. Cows can get skin cancer too.

[lpetrich]

Let's estimate how feasible it would be to be photosynthesis-powered.

Our bodies consume about 2000 food calories / day, or 100 watts.

Sunlight energy arrives at the Earth's orbit at a rate of about 1366 watts/m². So at perfect efficiency, we'd need a little more than a square foot of collector to be completely solar-powered. Current photovoltaics technology is at about 15% efficiency, and one would need about a square meter. However, they produce electricity and they don't assemble food molecules, which would produce further inefficiency.

Photosynthesis more-or-less works like a photovoltaic cell coupled to an electrolytic cell. The photovoltaic-cell part is the antenna complexes, where the chlorphyll molecules live. The electrolytic-cell part is an elaborate electron-transfer apparatus that transfers electrons from water molecules from biomolecules. When they are stripped from the water molecules, they become oxygen molecules and hydrogen ions. Electrons transferred to biomolecules pluck hydrogen ions out of the surrounding water.

From Photosynthetic efficiency, this process has only 5% efficiency in converting sunlight energy to biomolecule chemical energy. Thus, we'd need about 3 square meters of area, or 5.5 ft by 5.5 ft.

Photosynthesis saturates at about 100 watts/m² of sunlight, making it only about 10% efficient at midday.

This means that we'd need an area of about 6 m * 6 m or 20 ft * 20 ft.

So being photosynthesis-powered won't work.

[Ray Moscow]

I suppose that helps explains why there aren't any photosynthesis-powered large animals.

Smaller animals have a larger surface-to-volume ratio.

[anthrosciguy]

Originally Posted by lpetrich

Let's estimate how feasible it would be to be photosynthesis-powered.

Our bodies consume about 2000 food calories / day, or 100 watts.

Sunlight energy arrives at the Earth's orbit at a rate of about 1366 watts/m². So at perfect efficiency, we'd need a little more than a square foot of collector to be completely solar-powered. Current photovoltaics technology is at about 15% efficiency, and one would need about a square meter. However, they produce electricity and they don't assemble food molecules, which would produce further inefficiency.

Photosynthesis more-or-less works like a photovoltaic cell coupled to an electrolytic cell. The photovoltaic-cell part is the antenna complexes, where the chlorphyll molecules live. The electrolytic-cell part is an elaborate electron-transfer apparatus that transfers electrons from water molecules from biomolecules. When they are stripped from the water molecules, they become oxygen molecules and hydrogen ions. Electrons transferred to biomolecules pluck hydrogen ions out of the surrounding water.

From Photosynthetic efficiency, this process has only 5% efficiency in converting sunlight energy to biomolecule chemical energy. Thus, we'd need about 3 square meters of area, or 5.5 ft by 5.5 ft.

Photosynthesis saturates at about 100 watts/m² of sunlight, making it only about 10% efficient at midday.

This means that we'd need an area of about 6 m * 6 m or 20 ft * 20 ft.

So being photosynthesis-powered won't work.

Damn, there goes my weekend project.

[Rie]

Sometimes fluorescent light is used to help depression. And some people have a need to be awake at night.
My younger daughter is very light sensitive and copes by sleeping in the daytime.

[Eudaimonist]

Photosynthesis won't allow one to survive without eating, because we don't have roots that we can stick in the ground to get our nutrients.

I would rather hold out for phosphorescent skin that one can turn on at will.

It would be fun at raves, anyway.


eudaimonia,

Mark

[Notta]

I'd like to be able to photosynthesize and breathe out oxygen. Just think of the possibilities! If humans were able to photosynthesize even a very small amount, it would still help remove excess CO₂ from the atmosphere and improve the O₂ levels. In places like Bejing, it might even improve the quality of life.