A tale of two cesspits: DNA reveals intestinal health in Medieval Europe
and Middle East
New research proves the feasibility of retrieving bacterial DNA from
ancient latrines

Date:
October 5, 2020
Source:
Max Planck Institute for the Science of Human History
Summary:
Analysis of 14th-15th century latrines in Jerusalem and Riga,
Latvia identifies some of the microbes resident in the guts of
these pre- industrial populations, illuminating how gut contents
have changed since medieval times.



FULL STORY ==========================================================================
A new study published this week demonstrates a first attempt at using
the methods of ancient bacterial detection, pioneered in studies of
past epidemics, to characterize the microbial diversity of ancient gut
contents from two medieval latrines. The findings provide insights
into the microbiomes of pre- industrial agricultural populations,
which may provide much-needed context for interpreting the health of
modern microbiomes.


==========================================================================
Over the years, scientists have noted that those living in industrialized societies have a notably different microbiome compared to hunter-gatherer communities around the world. From this, a growing body of evidence has
linked changes in our microbiome to many of the diseases of the modern industrialized world, such as inflammatory bowel disease, allergies,
and obesity. The current study helps to characterize the change in gut microbiomes and highlights the value of ancient latrines as sources of bio-molecular information.

Ancient Gut Microbiomes: Exploring the Bowels of History Piers Mitchell
of Cambridge University specializes in the gut contents of past people
through analysis of unusual substrates. By looking at the contents of archaeological latrines and desiccated faeces under the microscope, he
and his team have learned volumes about the intestinal parasites that
plagued our ancestors.

"Microscopic analysis can show the eggs of parasitic worms that lived
in the intestines, but many microbes in the gut are simply too small
to see," comments Mitchell. "If we are to determine what constitutes
a healthy microbiome for modern people, we should start looking at the microbiomes of our ancestors who lived before antibiotic use, fast food,
and the other trappings of industrialization." Kirsten Bos, a specialist
in ancient bacterial DNA from the Max Planck Institute for the Science
of Human History and co-leader the study, was first skeptical about the feasibility of investigating the contents of latrines that had long been
out of order.



==========================================================================
"At the outset we weren't sure if molecular signatures of gut contents
would survive in the latrines over hundreds of years. Many of our
successes in ancient bacterial retrieval thus far have come from
calcified tissues like bones and dental calculus, which offer very
different preservation conditions.

Nevertheless," says Bos, "I was really hoping the data here would change
my perspective." The team analyzed sediment from medieval latrines in Jerusalem and Riga, Latvia dating from the 14th-15th century CE. The
first challenge was distinguishing bacteria that once formed the ancient
gut from those that were introduced by the environment, an unavoidable consequence of working with archaeological material.

The researchers identified a wide range of bacteria, archaea, protozoa, parasitic worms, fungi and other organisms, including many taxa known
to inhabit the intestines of modern humans.

"It seems latrines are indeed valuable sources for both microscopic and molecular information," concludes Bos.

No Modern Matches for Ancient Microbiomes Susanna Sabin, a doctoral
alumna of the MPI-SHH who co-led the study, compared the latrine DNA
to those from other sources, including microbiomes from industrial and
foraging populations, as well as waste water and soil.



==========================================================================
"We found that the microbiome at Jerusalem and Riga had some common characteristics -- they did show similarity to modern hunter gatherer microbiomes and modern industrial microbiomes, but were different enough
that they formed their own unique group. We don't know of a modern
source that harbors the microbial content we see here." The use of
latrines, where the faeces of many people are mixed together, allowed
the researchers unprecedented insight into the microbiomes of entire communities.

"These latrines gave us much more representative information about the
wider pre-industrial population of these regions than an individual
faecal sample would have," explains Mitchell. "Combining evidence from
light microscopy and ancient DNA analysis allows us to identify the
amazing variety of organisms present in the intestines of our ancestors
who lived centuries ago." Despite the promise of this new approach for investigating the microbiome, challenges remain.

"We'll need many more studies at other archaeological sites and time
periods to fully understand how the microbiome changed in human groups
over time," says Bos. "However, we have taken a key step in showing that
DNA recovery of ancient intestinal contents from past latrines can work."

========================================================================== Story Source: Materials provided by Max_Planck_Institute_for_the_Science_of_Human_History.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Susanna Sabin, Hui-Yuan Yeh, Aleks Pluskowski, Christa Clamer,
Piers D.

Mitchell, Kirsten I. Bos. Estimating molecular preservation of the
intestinal microbiome via metagenomic analyses of latrine sediments
from two medieval cities. Philosophical Transactions of the Royal
Society B: Biological Sciences, 2020; 375 (1812): 20190576 DOI:
10.1098/ rstb.2019.0576 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201005005927.htm

--- up 6 weeks, 6 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)