Page 4 - Dream 2047 April 2021

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Recent research has shown that microbes living in ancient sediment below the seafloor are sustained primarily by chemicals created by the natural irradiation of water molecules. A team of researchers from the University of Rhode Island's Graduate School of Oceanography and their collaborators have revealed these findings.
According to them, the
process is driven by the
radiolysis of water-the
splitting of water molecules
into hydrogen and oxidants
as a result of being exposed
to naturally occurring
radiation. The resulting molecules become the primary source of food and energy for the microbes living in the sediment. According to the researchers, “the marine sediment actually amplifies the production of these usable chemicals; in fact, the sediment makes the production of hydrogen much more effective”.
The discoveries resulted from a series of laboratory experiments conducted in the Rhode Island Nuclear Science Centre where vials of wet sediment from various locations in the Pacific and Atlantic Oceans, collected by the Integrated Ocean Drilling Program and by US research vessels, were irradiated. When the researchers compared the production of hydrogen to similarly irradiated vials of seawater and distilled water, it was found that the sediment amplified the results by as much as a factor of 30 (Nature Communications, 27 February 2021 | DOI: 10.1038/s41467-021-21218-z)
According to the resear- chers, the implications of the findings are significant. They say, “If you can support life in subsurface marine sediment and other subsurface environments from natural radioactive splitting of water, then maybe you can support life the same way in other worlds”. Some of the same minerals are present on Mars, and as long as you have those wet catalytic
Scanning electron micrograph of Lactobacillus
minerals, you’re going to have this process. If you can catalyse production of radiolytic chemicals at high rates in the wet Martian subsurface, you could potentially sustain life at the same levels that it's sustained in marine sediment.”
L
systems without causing disease. There are many species of lactobacillus. It is also found in some fermented foods like yogurt and in dietary supplements.
New research from North Carolina State University in USA has revealed that depending on the situation, probiotic Lactobacillus bacteria use enzymes to manipulate bile acids and promote their own survival in the gut. These findings further make clear the complicated relationship between bile acids and gut bacteria and could eventually enable researchers to design lactobacilli with therapeutic properties, and thus help in engineering a healthier human gut environment.
According to scientists, as bile acids move through the gut, they are initially chemically modified through the addition of an amino acid (such as glycine or taurine), creating a complex “conjugated” bile acid pool. Some gut bacteria have enzymes, called bile salt hydrolases (BSHs), which can split or “deconjugate” these amino acids from the bile acids, allowing other bacteria to further transform the bile acids as they pass through the colon.
It was believed that probiotic bacteria like Lactobacillus have BSHs that deconjugate the bile acid and render it less toxic which allows the bacteria to survive. But, according to Casey Theriot, associate professor of infectious disease at NC State the reality is a lot more complex because these enzymes are more specific than believed earlier.
According to the scientists, the interplay between bile and bacteria has a huge impact on their ability to live, thrive or die in a very competitive environment. So, they set out to further investigate that relationship. They did both in vitro and in vivo experiments to determine how and whether BSHs reduced bile acid toxicity. They found that bile acid toxicity was not merely dependent upon whether the bile acid was conjugated or deconjugated by a BSH; rather, the relationships were dependent upon the type of bile acid, the bacteria being acted upon, and which BSH was present (Proceedings of the National Academy of Science, 9 February 2021).
When the researchers altered the BSH composition of these Lactobacillus strains, they found that “their tolerance of the bile acids and thus their competitive fitness were also altered”. They say, "These BSH enzymes have diverse properties. Bacteria pick up and drop off enzymes regularly-sometimes they pick up enzymes that will help them survive (make bile acid less toxic) or they could pick up an enzyme that will hurt competition”.
Biman Basu is a former editor of the Science Reporter, published by CSIR. Email: bimanbasu@gmail.com
Lactobacillus alters bile acids to create favourable gut environment
actobacillus are human-friendly bacteria that normally live in our digestive, urinary, and genital
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