Digestive workings of the Burmese Python.

While vertebrates typically exhibit cell plasticity within their intestinal epithelium, as is necessary, Burmese Pythons exhibit this characteristic to an extreme. Cell plasticity can be defined as a cell’s adaptability. Cells exhibiting plasticity can reconfigure their phenotype to change, such as dedifferentiation, which is the reversion of a specialized cell to a less specialized form (Bévant, Kevin et al., 2023). This typically occurs in response to some stimulus, such as the luminal nutrients detected in food when a python feeds (Secor et al., 2000). Burmese Pythons’ intestines dramatically change in size and composition based on their meals. Their small intestine expands, and reaches peak size approximately three days after feeding. The microvilli lining their intestine grow much larger during the first 24 hours post-feeding, greatly increasing the surface area with which nutrients can be absorbed (Lignot et al., 2005).

The Vertebrate perspective: Calcium and Phosphate

Calcium and phosphate levels are highly regulated in vertebrates, and it is necessary to highlight some of the mechanics behind their regulation. When calcium levels in the blood are low, Parathyroid Hormone (PTH) is secreted. PTH raises Calcium levels by encouraging bone resorption, which releases calcium and phosphate into the bloodstream (Babić Leko et al., 2021). PTH actually lowers phosphate levels despite this, because PTH inhibits phosphate reabsorption, leading to the release of phosphate via urination (Leung, E. 2021). Calcitonin, on the other hand, prevents bone resorption and promotes the use of calcium to build onto existing bone (Babić Leko et al., 2021). This lowers calcium levels in the bloodstream, and is started by the detection of high calcium.

Methods of examination

As seen in (Secor et al., 2000), the intestines of the pythons are examined using electron microscopy. Both the transmission (TEM) and scanning (SEM) methods are used in the aforementioned paper. Electron microscopy uses high energy electron beams to produce clear images of exceptionally small details, down to nanometers and smaller (García de Abajo, 2010). The TEM method uses ultra-thin samples of a subject to examine internal structure (Franken et al., 2020), while SEM enables the visualization of surface structures and topography of samples (Krishnan, 2021). Using either x-rays or electron microscope techniques, atoms within samples can be excited and release characteristic X-Rays, aptly named as each element produces a unique X-Ray using these methods. These photons are collected via a specialized detector which then feeds the resulting spectrum into specialized software for both quantitative and qualitative analysis (M. Scimeca et al., 2018). This provides insight as to the exact elements comprising examined structures, which of course applies to our topic in the form of determining phosphate and calcium makeup within intestinal cells.

Appearance of the spheroids

Under different diets and timeframes, the apical crypts in juvenile Burmese pythons were found to contain particles of different elemental makeup. When fasting, these crypts (examined with electron microscopy) were deflated and quite small as seen in figure 1A (Lignot et al., 2025). When fed normally, using whole mice, the crypts contained spherical particles exhibiting a ring-like pattern similar to the inside of a tree as seen in figure 2 (Lignot et al., 2025). Fed a diet of mice without any bones inside, the particles within these crypts were instead splotchy, with dark splatters inside, as seen in figure 4(Lignot et al., 2025). The researchers then fed pythons boneless mice that were injected with a concentrated calcium product. These pythons had crypts with a similar ringed particle inside, but this particle was darker at its center, and seemed more concentrated, as seen in figure 5 (Lignot et al., 2025).

Elemental analysis

EDX analysis was used on the particles within each crypt to determine the elemental makeup of each particle. The normally-fed snakes’ results are shown in figure 3 (Lignot et al., 2025), with the particles predominantly being comprised of calcium, phosphorous, carbon, and oxygen. Figure 4 (Lignot et al., 2025), shows the results of EDX analysis on the low-calcium diet snakes. These particles instead have carbon, oxygen, phosphorous, and iron, with no significant notes of calcium. The calcium-concentrate fed snakes are examined in Figure 5, where we can see many more elements joining the fray. These particles are comprised of carbon, oxygen, magnesium, sulfur, phosphorus, calcium, and iron. The paper suggests that the reason for discrepancies between the makeup of each particle is due to these crypts acting as an overflow region to hold elements that the surrounding cells are in excess of until they are needed. This is a reasonable hypothesis, as the calcium deficient snakes do not have any calcium in said crypts.

Regulation

Snakes regulate their blood-calcium levels using calcitonin to put high levels of calcium to use, reinforcing bones. PTH is used when there is not enough calcium, and it promotes the breakdown of bone to provide the body with calcium. As seen by the graphs in Figure 6: Fasting snakes exhibit moderate calcium and calcitonin levels, and very low PTH. A normal diet shows slightly less calcium and calcitonin, but maintains a higher, yet still low PTH level. Over the 5 boneless feedings, calcium levels gradually lower, and calcitonin levels gradually rise. PTH levels rise dramatically at the 4th and 5th feedings, which is also when the calcium levels lower the most considerably (Lignot et al., 2025).

Conclusions

This paper demonstrates how the presence of different elements regulates the presence of different hormones, and how these hormones affect the transportation of said elements. It is interesting to see how these cells have adapted to a role of regulating an excess of calcium and phosphorous in animals that consume the entire skeleton of their prey. This paper has mostly convinced me of their discovery of a previously undiscovered cell. This excretory intestinal cell is unlike any of its surrounding cells. It does not entrap lipids, unlike its neighbors (Lignot et al., 2025), and is documented as producing these spheroids to get rid of excess calcium and phosphorous from bone matter. Their experiments were well executed, yet I do believe that more experimentation is warranted to fully cement this as a new cell type.

References (10)

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