Octopuses are doomed to be orphans from an early age. After laying their eggs, the female octopus begins to eat, injures itself, peels off its skin, and bites the ends of its tentacles.
When the young octopus hatched, its mother died. A few months later, her father died.
The short and tragic life of the octopus has long fascinated scientists. In 1944, researchers hypothesized that mating was somehow suppressing the molecular “self-destruction” stage in marine life.
It’s been almost 80 years, but this vague hypothesis is finally being formed. Researchers have recently discovered that mating appears to alter several important biochemical pathways based on cholesterol in female octopuses to various hormones.
Molecular biologist Z., who conducted research at the University of Chicago. “We know that cholesterol is important in terms of nutrition, but it is also important for various signaling systems in the body,” explains Yang Wang.
“It is involved in everything from the elasticity of cell membranes to the production of stress hormones, but it was a big surprise that its life cycle also played a role in this process.”
Some cholesterol precursors are highly toxic in humans. Thus, genetic disorders that increase cholesterol metabolism can lead to serious developmental and behavioral problems, including recurrent self-harm and eating disorders. Difficult situations can even be life-threatening.
The symptoms are surprisingly reminiscent of female octopuses of the last days, suggesting that researchers may be aiming for something.
It took several years to get there, and mostly because of the small and invaluable body found in this octopus and squid.
In 1977, researchers discovered that the optic gland played a role in the programmed death of the octopus.
This organ is similar to the human pituitary gland. It is located in the middle of the octopus’s eye and is associated with the sexual development and aging of cephalopods. When it is removed from the female octopus, the creature lives for several months after laying its eggs.
In 2018, scientists took this knowledge and arranged the RNAs of two optical glands in two female octopuses at different stages of decline.
As the octopus neared death, the authors found high levels of activity in sex hormones, insulin-like hormones, and several genes that control cholesterol metabolism.
Now, a few years later, some of the same researchers have directly analyzed the molecules released from this organ in both paired females and paired females.
After mating, the optic gland actually secretes more sex hormones, insulin-like hormones, and cholesterol precursors.
All three molecules can contribute to the signaling systems that eventually lead to death. Or perhaps the accumulation of these deadly molecules in the octopus’s body, as in humans.
While the optic gland has previously been linked to the production of cephalopod sex hormones, the other two pathways have only recently been identified in the “self-destruction” sequence.
In the future, Wang and his colleagues hope to further explore the “downstream” to see what other molecules of death exist at this astonishing time.
“It simply came to our notice then [octopuses] They go through this progression of seemingly insane changes before they die, ”said Clifton Ragsdale, a neurobiologist at the University of Chicago.
“Maybe it’s two processes, maybe it’s three or four. Now we have at least three independent pathways to steroid hormones, and they can take into account the many effects that these animals have.”
Wang said he is thrilled that his team has identified two rodents identified from other studies.
“[N]”Now our research shows that these octopuses are also present in octopuses.”
“It was very interesting to see the similarities of such different animals.”
The study was published Current biology.