Natures wonders: hungry pythons change their hearts (Introduction)

by David Turell , Friday, October 04, 2024, 00:06 (18 days ago) @ David Turell

After a giant meal:

https://www.the-scientist.com/how-pythons-adapt-their-hearts-after-a-big-meal-72185

"If a human ate 50 percent of their weight in one sitting, their body might not take it. Their stomach would expand, and their heart would begin trying to furiously pump blood to sustain the metabolism needed to digest such a meal. But pythons do this time and again—in the wild, the Burmese python and the ball python scarcely encounter food and can go up to two years without eating. So, they eat as much as possible when they have the opportunity, sometimes consuming up to half their body weight.

"Researchers have now begun to sort out how the python’s organs, specifically the heart, handles such a stress. In a new study, published in Proceedings of the National Academy of Sciences, researchers showed that heart muscle fibers in fed pythons became less stiff while still producing more force than those in starved pythons.

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"The researchers saw that the hearts of fed pythons increased by about a quarter compared to the hearts of those that were starved. Using a rheometer which applies force to a sample, researchers found that the heart tissue from pythons that had fed were less stiff than those that had not.

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"They found that those from fed pythons generated more force. By improving the efficacy of the contractile proteins of the heart, the pythons could then have a means to increase the amount of blood being pumped, said Wang.

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"The team stained the nucleus of the muscles cells and calculated a parameter called chromatin condensation. In fact, the chromatin was more condensed in starved pythons than in fed animals.

"Next, they looked into the gene expression changes during feeding which could be driving these effects. RNA sequencing between the fed and non-fed pythons revealed that feeding led to increases in genes involved in endoplasmic reticulum processes and protein. To Leinwand, this suggests that the body ramped up protein production to make the organs, in this case the heart, bigger.

"Wang hopes that future studies investigate the drivers of epigenetic and gene expression changes. “Is it something like a factor circulating in the plasma or is it something that happens as a consequence of the mechanical loading of the heart?'”

Comment: the mechanism is still not fully clarified, but it appears to be an adaption developed over time. The other question is how does a python go so long without a meal? A slow mtabolism as in torpor or hibernation?