CLOSE
Original image
istock

Immunology Study Suggests the Appendix Has a Use After All

Original image
istock

The appendix has long had a reputation as a redundant organ with no real function. Doctors often remove it even in mild cases of appendicitis to prevent future infection and rupture, which may not always be necessary. But new research on the way innate lymphoid cells (ILCs) protect against infection in people with compromised immune systems may redeem this misunderstood organ. 

“Our study was to investigate the innate lymphoid cells in the gut [of mice] and how they might contribute to the function and protection of the gut,” Gabrielle Belz, of Melbourne’s Walter and Eliza Hall Institute of Medical Research, tells mental_floss. “At the same time, we were interested to know how different immune cells impacted the different parts of the gut.”

ILCs can be found “underlying all the body’s surfaces, including the skin, the lungs, the gut, and the reproductive tract, and play a very important and broad role in protecting the body from infections and responses to environmental insults,” says Belz.  

Belz’s team worked in collaboration with a team headed by Eric Vivier at the Centre d’Immunologie de Marseille-Luminy, France. Together, they set out to explore how ILC3s (one group of ILCs) function during and after a gut infection—particularly how they altered immune protection.

The study, published in Nature Immunology, found that in mice, gut infections begin in the cecum, a small pouch that is considered to be the beginning of the large intestine, and which contains a large patch of ILC3s near its tip. The team infected mice with the murine pathogen Citrobacter rodentium, which establishes first in the cecum. Then they removed the ILC3s, which caused shrinkage of the cecum and inflammation in the colon. Moreover, they uncovered a “layered contribution” of each of the different types of immune cells in the cecum.

“Thus, surprisingly, altering the balance of immune cells significantly affected what was happening in the cecum, suggesting that a similar effect might occur in humans in the appendix,” Belz says. “This highlights that simply disposing of this organ may not always be in our best interests.” 

While the appendix is not required for digestive functions in humans, Belz tells mental_floss, “It does house symbiotic bacteria proposed by Randal Bollinger and Bill Parker at Duke University to be important for overall gut health, but particularly when we get a gut infection resulting in diarrhea.”

Infections of this kind clear the gut not only of fluids and nutrients but also good bacteria. Their research suggests that those ILCs housed in the appendix may be there as a reserve to repopulate the gut with good bacteria after a gut infection.

ILCs are hardier than other immune cells, and thus vital to fighting bacterial infections in people with compromised immune systems, such as those in cancer treatment; they are some of the few immune cells that can survive chemotherapy. 

Belz says that changing the way the appendix is regarded—from vestigial to integral—may also help prevent unnecessary appendix operations. In non-emergency cases of appendicitis, for instance, non-surgical treatments such as antibiotics “can be used to endeavor to calm the inflammation down in the cecum and appendix,” she says. And a healthy appendix may be helping to keep your gut microbiome balanced: Belz has conducted prior research that shows that diet, particularly leafy green and cruciferous vegetables, may help produce ILCs as well. 

More study can also help understand how ILCs play a role in allergic diseases such as asthma, inflammatory bowel disease, and psoriasis. At the very least, Belz says, “It seems likely that [the appendix] is an integral part of the immune system.”

Original image
iStock
arrow
science
The Delicious Chemistry of Sushi
Original image
iStock

The secret to sushi's delicious taste is invisible to the human eye. Chefs spend years training to properly prepare the Japanese culinary staple, which consists of fresh fish and seasoned rice, either served together or wrapped in seaweed. At its most elemental, as the American Chemistry Society's latest Reactions video explains below, the bite-sized morsels contain an assortment of compounds that, together, combine to form a perfectly balanced mix of savory and sweet. They include mannitol, iodine, and bromophenol, all of which provide a distinctive tang; and glutamate, which adds a savory, rich umami flavor (and turns into MSG when it's combined with a sodium ion).

Take a bite of science, and learn more fun facts about the Japanese culinary staple's long history and unique preparation method by watching the video below.

Original image
Courtesy the University of Colorado Boulder
arrow
science
Fossilized Poop Shows Some Herbivorous Dinosaurs Loved a Good Crab Dinner
Original image
Lead author Karen Chin of the University of Colorado Boulder
Courtesy the University of Colorado Boulder

Scientists can learn a lot about the prehistoric world through very, very old poop. Just recently, researchers from the University of Colorado-Boulder and Kent State University studying fossilized dinosaur poop discovered that some herbivores weren't as picky about their diets as we thought. Though they mostly ate plants, large dinosaurs living in Utah 75 million years ago also seem to have eaten prehistoric crustaceans, as Nature News reports.

The new study, published in Scientific Reports, finds that large dinosaurs of the Late Cretaceous period seem to have eaten crabs, along with rotting wood, based on the content of their coprolites (the more scientific term for prehistoric No. 2). The fossilized remains of dinos' bathroom activities were found in the Kaiparowits rock formation in Utah's Grand Staircase-Escalante National Monument, a known hotspot for pristine Late Cretaceous fossils.

"The large size and woody contents" of the poop suggest that they were created by dinosaurs that were well-equipped to process fiber in their diets, as the study puts it, leading the researchers to suggest that the poop came from big herbivores like hadrosaurs, whose remains have been found in the area before.

Close up scientific images of evidence of crustaceans in fossilized poop.
Chin et al., Scientific Reports (2017)

While scientists previously thought that plant-eating dinosaurs like hadrosaurs only ate vegetation, these findings suggest otherwise. "The diet represented by the Kaiparowits coprolites would have provided a woody stew of plant, fungal, and invertebrate tissues," the researchers write, including crabs (Yum.) These crustaceans would have provided a big source of calcium for the dinosaurs, and the other invertebrates that no doubt lived in the rotting logs would have provided a good source of protein.

But they probably didn't eat the rotting wood all year, instead munching on dead trees seasonally or during times when other food sources weren’t available. Another hypothesis is that these "ancient fecal producers," as the researchers call them, might have eaten the rotting wood, with its calcium-rich crustaceans and protein-laden invertebrates, during egg production, similar to the feeding patterns of modern birds during breeding season.

Regardless of the reason, these findings could change how we think about what big dinosaurs ate.

[h/t Nature News]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios