Did poop/gut evolve with helped fuel the Cambrian explosion?

Amazing stuff! How did bowel movement and excrement develop in the first place? Still an open question, I believe.

One animal's poop is another animal's treasure!

"The driving force behind this biological big bang, they argue in a recent Trends in Ecology & Evolution review paper, just might have been feces.

While many early animals had already appeared in the fossil record during the preceding Ediacaran period, the Cambrian explosion marked the emergence of animal guts, which naturally produced a whole bunch of animal poop. Even so, fossilized turds—known as coprolites—from this time period are hard to come by, and those that are unearthed tend not to attract much attention. Many are left to gather dust in archives, ... or simply abandoned at the dig site.

For the new study, Kimmig and co-author Russell Bicknell analyzed coprolites recovered from more than 35 deposits around the globe, all dating back to before and during the Cambrian explosion. The prehistoric poo came in all shapes and sizes, from microscopic pellets to coprolites measuring several centimeters long and packed with crushed shells and other bits of undigested food. Some had dissolved upon striking the seafloor, creating something evocatively referred to as an “exploded fecal carpet.” (Maybe those marine critters should have laid off the iceberg lettuce...)

The researchers discovered that, as the Cambrian progressed, animal dung became larger, more common, and more complex, reflecting the development of more sophisticated digestive systems. As more and more of this excrement accumulated, the study authors reason, it would have carried organic matter and valuable nutrients from the rich shallows down into the deep ocean, potentially making these environments more habitable. “Together, these fossils show animals were beginning to process and then redistribute organic matter using entirely novel pipelines ,” ... Such a “fecal revolution,” they explain, may have set the stage for an eruption of new life. ..."

From the highlights and abstract:

"Highlights

The ‘Cambrian Radiation’ comprises the rapid diversification of marine organisms and ecological niches during the Ediacaran to Cambrian Periods. It is also the time during which animals with guts first appear. The appearance of guts, in turn, leads to fecal matter, fossils of which are preserved as coprolites.

Fecal matter is rarely preserved in the Cambrian. However, in a few assemblages, the diversity and development of fecal matter are observed. There was little fecal matter available at the onset of the Cambrian, while larger and more diverse fecal matter became available by the middle Cambrian.

We assess the effect that increased availability of fecal matter had on deeper water environments and how this made such environments habitable for Cambrian organisms.

Combining these observations with data on digestive tracts and biogeochemistry of nutrient cycling in the Cambrian demonstrates that fecal matter played a significant role in driving the Cambrian Radiation.

Abstract

Coprolites—fossil material extruded from an animal’s digestive system—represent a rare insight into trophic interactions in deep time. However, while the first animals appeared about 600 million years ago, the first coprolites are only observed in the earliest Cambrian.

Conversely, in modern oceans, fecal pellets are an important part of the particulate organic carbon in the water column and the global flux of organic carbon to deep water.

In this review, we analyze the impact of the advent of fecal matter on the Cambrian Radiation by examining coprolites, analyzing animal biology, and contextualizing this through the role of fecal pellets in the oceanic nutrient cycle. We illustrate the central position of coprolites in driving the Cambrian Radiation."

ScienceAdviser

On the origin of feces: how animal poo drove Earth’s greatest evolutionary event

How an ‘explosion of excrement’ changed Earth's ecosystems forever

The Cambrian fecal revolution: Fueling the Cambrian Radiation (no public access)

A curious collection of Cambrian coprolites (fossilized poop)

Machine learning designs efficacious synthetic microbial communities as antibiotics

Good news! Synthetic antibiotics by design based on microbiota.

"... The research team set out to identify C. difficile’s “friends” and “foes;” in other words, those that tend to either co-occur with C. difficile or those that may reduce the growth of C. difficile. They gathered information on the human microbiome from 12 previously published studies, which included microbiome sequencing data and clinical diagnoses of C. difficile colonization. They then used machine learning to home in on the key features of microorganisms that were positively and negatively associated with C. difficile.

Thirty-seven strains of bacteria were found to be negatively correlated with C. difficile. In other words, when these microorganisms were present, there was no C. difficile infection.

Another 25 bacteria were positively correlated with C. difficile, meaning that they were present alongside C. difficile infection.

In the lab, the researchers then combined bacteria that appeared to repress C. difficile and developed a synthetic version of a fecal transplant.

When tested in vitro and given orally to mice, the synthetic microbiome therapy significantly reduced growth of C. difficile, resisted infection and was as effective as a traditional human fecal transplant. In mice, it was also shown to protect against severe disease, delay relapse and decrease severity of recurrent infections caused by antibiotic use. ..."

From the highlights and abstract:

"Highlights

• Machine learning designs microbial communities through robust cross-cohort signals

• Synthetic consortia form stable communities in vivo suppressing C. difficile

• Proline-fermenting strains are necessary and sufficient for C. difficile repression

• P. anaerobius is as efficacious as a human fecal transplant in a gnotobiotic model

Summary

Clostridioides difficile, a major cause of antibiotic-associated diarrhea, is suppressed by the gut microbiome, but the precise mechanisms are not fully described.

Through a meta-analysis of 12 human studies, we designed a synthetic fecal microbiota transplant (sFMT1) by reconstructing microbial networks negatively associated with C. difficile colonization.

This lab-built 37-strain consortium formed a functional community suppressing C. difficile in vitro and in animal models.

Using sFMT1 as a tractable model system, we find that bile acid 7α-dehydroxylation is not a determinant of sFMT1 efficacy while one strain performing Stickland fermentation—a pathway of competitive nutrient utilization—is both necessary and sufficient for the suppression of C. difficile, replicating the efficacy of a human fecal transplant in a gnotobiotic mouse model.

Our data illustrate the significance of nutrient competition in suppression of C. difficile and a generalizable approach to interrogating complex community function through robust methods to leverage publicly available sequencing data."

A Microbe from Poo Suppresses Bacterial Infection | The Scientist "A group of gut bacteria successfully hindered recurrent Clostridium difficile infection in mice, offering alternative therapeutic strategies to antibiotics and fecal transplant."

Synthetic microbiome therapy suppresses bacterial infection without antibiotics (original news release) "Precise, targeted treatment using limited strains of gut bacteria effectively protected against C. difficile infection, severe symptoms and recurrent infections in mice"

A designed synthetic microbiota provides insight to community function in Clostridioides difficile resistance (open access)

Figure 1. Meta-analysis of studies enables rational design of communities that correlate with C. difficile