How weird looking fish are helping research on organ transplantation
Why radiation is a lethal risk to the Mars mission, humans with cat whiskers, mangroves as stores of carbon, changing memories, and eye shapes in frogs.
How anglerfish fuse is spawning research on organ transplantation
Your immune system is constantly looking out for attackers. Such attackers can be viruses, bacteria, and parasites. Over the course of millions of years, the immune system has developed a way to separate the cells of the body (“self”) from foreign cells (“non-self”). This is one of the reasons organ transplantations need the immune system to be suppressed for compatibility between the donor’s organ and the recipient’s body.
During pregnancy, the placenta has proteins that stop the immune system of the mother from attacking her unborn child. In an earlier newsletter, I talked about how some of these proteins are related to genes that derived from viruses. Yes, you heard right.
Viruses are responsible for some of the genes that led to the developmental process of pregnancies.
Wouldn’t it be great if there was an animal we could look at that had a different kind of an immune system? By studying such an animal we could learn more about the basic functioning of components of their defective immune responses. It could also lead to new ways of thinking about organ transplants in people .
Anglerfish are the weirdest looking fish because they have an angler or fishing rod on their head and they use a flowing light as lure. They’re not fast swimmers, but they can lurk quietly while prey are mesmerized by light. The light that is emitted is created by bioluminescent bacteria that form a symbiotic relationship. (There are also kinds of squids that form symbiotic glowing relationships with bacteria).
(Photo courtesy, Arhan)
Finding a mate anywhere for any species is a challenge. In the vastness of the sea, it's nearly impossible.
Anglerfish have solved it by fusing together and giving now meaning to "till death do us part." But this adaptation left scientists baffled.
In many anglerfish, the male is a tiny parasite that latches on to the body of the female with it's teeth after which both of them fuse. The male is permanently parasitic. Only about 1% of males find females in the barren deep sea, but once they do, they never let go. A female can carry six or more males that have fused with its body. The female is 60 times larger than the male.
The mixing of blood of two different individuals should trigger a massive immune response in anglerfish just as it does in humans. But it doesn’t. There are three ways to get around this.
It could be that anglerfish only mate with other anglerfish that have similar cells of the immune system. This raises the question of how they would recognize such mates in the vast ocean. Scientists have found that this is not the case.
The second scenario is that all anglerfish might be very similar genetically so all of their immune systems are alike. This also turns out not to be the case. Biological variation is a boon to anglerfish just as they are for other animals.
The third is that they have lousy immune systems.
In an article published in Science what researchers found is that anglerfish have defective immune responses that allow extremely parasitic males to fuse with females. No one knows how they escape getting infected by bacteria and viruses in the ocean, and that’s an open line of inquiry. But that’s the beauty of science. Answering one question opens the door to many others.
Back in the lab, the basic science of how anglerfish males and females fuse together is driving some pretty cool research on organ transplant acceptance.
In space, radiation kills.
This week, for my column in Hindustan Times, I wrote about human spaceflight. If we want to send humans to Mars and beyond, we need to worry about radiation risks. In internal documents a few years ago, NASA acknowledged the risk of radiation to sending humans to Mars.
In terms of radiation, sending someone to Mars is the equivalent of 10,000 chest X-rays.
The Earth's magnetosphere protects us from ionizing radiation. It extends to an average of 40,000 miles. The ISS is at a higher altitude than Jeff Bezos’ or Richard Branson’s flights. But since it is in low Earth orbit, it is still within the earth’s magnetosphere.
Radiation is a deadly risk that hasn’t entered the public discourse when talking about space travel. And if you read or watch sci-fi it’s hardly ever mentioned. It didn’t even figure among concerns in the otherwise excellent The Martian.
NASA estimates that the radiation exposure from one mission to Mars might exceed the lifetime limit of astronauts.
Currently there are no spacecraft that can shield against galactic cosmic rays.
How can we circumvent the risk from galactic cosmic rays? One of the coolest ideas (which won't happen in my lifetime) has been proposed by Chris Mason and other scientists. They imagine a future in which genetically modified humans include the gene for the damage-suppressor protein from radiation-resistant tardigrades. Tardigrades, ot water bears as they are also called, have genes that make them tolerate high doses of ionizing radiation.
Here's a fun fact for cat lovers. You already know your cat's whiskers are important in sensory perception. Did you know that humans also have the whiskers gene?
We would just need to gene edit the regulatory "switch" to turn it on.
Mangroves are key to preventing the climate crisis
“Blue carbon is the carbon stored in coastal and marine ecosystems.”
Blue carbon storage is critical to fighting climate change. A little known fact is that mangroves hold more carbon than tropical forests.
In fact, mangroves store more carbon per unit area than any other ecosystem on Earth (up to 10 times more than terrestrial forests). Mangrove protection and restoration is a low-tech solution with benefits for local economies, conservation, and prevention of flooding as well.
Pupil shapes in adult frogs and toads.
I’ve been in science publishing for a decade and a half and I have to say the figure below is one of the prettiest I’ve seen in any science journal with the possible exception of the “Brainbow” published in Nature a few years ago.
There are seven general categories of pupil shapes, but a tremendous amount of diversity. Who knew? Nature can be so wonderful and pretty.
What else I’ve read
"Creative ideas evolve from existing memories and impressions. Instead of new ideas being lit aflame by lightning bolts, they arise from the interweaving billions of microscopic sparks in the vast darkness of the brain." Wonderful essay.
Now, this is a fun read for inquisitive people of all ages. How animals sleep.
How psychologists turned statistical significance into a failure.
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Loving your blog. This is a must-read primer on the male angler fish: https://theoatmeal.com/comics/angler