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New research shows that a human stomach pathogen is attracted to bleaching



<img src = "https://scx1.b-cdn.net/csz/news/800/2019/3-newresearchr.jpg" alt = "New research shows that a human stomach pathogen is attracted to bleaching. The protein TlpD, which perceives the bleaching, is shown in the inset image: Arden Perkins

University of Oregon researchers have discovered a molecular mechanism by which the human gastric pathogen Helicobacter pylori is attracted to bleaching, also known as hypochlorous acid or HOCl. The study revealed that H. pylori uses a protein called TlpD to detect and respond to bleaching. The bacteria Salmonella enterica and Escherichia coli can detect bleaching in the environment using TlpD-like proteins.

The researchers suggest H. pylori uses the protein TlpD to detect sites of tissue inflammation that could help the bacteria colonize the stomach and possibly locate damaged tissue and nutrients. The publication " Helicobacter pylori detects bleach (HOCI) as a chemoattractant using a cytosolic chemoreceptor" appeared on August 29 in the journal PLOS Biology .

According to researchers, the H. pylori is particularly large, because in some developing regions it infects about half of the world's population with an infection rate of almost 1

00 percent. The bacterium lives in small pockets of the stomach, the so-called gastric glands, which are supposed to protect it from the hostile stomach environment.

H. pylori causes chronic inflammation and gastric ulcers. It is a major risk factor for stomach cancer, one of the most common cancers worldwide.

"One reason for studying this particular protein is that we know the navigation system that has Helicobacter pylori " It's really important that the bacteria infect themselves and cause disease, "said the executive Author Arden Perkins, a postdoctoral fellow at the University of Oregon, "If we find out what this protein is all about, we may be able to disrupt its function with a new drug."

H. pylori uses, like most bacteria, specific proteins to detect chemicals in their environment, and the process called chemotaxis allows them to regulate their flagella to move toward or away from compounds.

The research team investigated How Bacteria Respond to the Presence of Bleach Produced by White Blood Cells in Cells "It's important that we get the protein understanding of the bleaching sensor, "said study author Karen Guillemin, a professor of biology and a member of the UO Institute of Molecular Biology. "It turns out that this is not a machinery that applies only to Helicobacter pylori and it gives us insights into other bacteria with similar proteins."

Twenty-five years ago, work began to determine the molecular function of the TlpD protein, which the researchers knew to be involved in the regulation of bacterial flagella. They knew that TlpD is a sensor molecule, but did not know what it might perceive. To investigate the role of the uncharacterized protein, Perkins isolated the TlpD protein and two other proteins involved in the transmission of the molecular signal to the flagella.

"Isolation of the components of the molecular signaling system allowed for much clearer understanding Previous research had shown that reactive oxygen species could be the compounds that were perceived by the TlpD protein, so Perkins tested various compounds, including hydrogen peroxide, superoxide, and bleach. The surprising results showed that TlpD produces an attractive signal when exposed to bleaches.

  New research has shown that a human gastric pathogen is attracted to bleaching agents.
The bacterial gastric pathogen Helicobacter pylori swims to a bleach-filled needle Bacterium uses a protein called TlpD (center) to recognize the bleach as an attractant. Photo credits: Arden Perkins

Although it did not seem to be of interest to the bacteria to feel attracted to a harmful chemical, further studies with living bacteria have confirmed that the bacteria are not damaged and attracted by bleach sources in concentrations produced by the human body.

Perkins and co-workers could not deny what they saw after repeatedly conducting the experiment and searching for various explanations.

"This project was based on this truly rigorous molecular insight, and then we considered what this means for human behavior," said Guillemin. "We really could continue with the firm conviction that the phenomenon we studied makes sense at a molecular level." But H. pylori is unusual in settling for decades in inflamed tissue without being eradicated by bleaching. The research team believes H. pylori can be grown to bleach to settle in the gastric glands, which are full of white blood cells but serve as crucial reservoirs for the bacteria.

Surprisingly, the researchers found that the toxic compound produced by the white blood cells could be interpreted by the invading bacteria as an attraction signal.

"We know that the bacteria can live in inflamed tissue for years during their infection, so this result suggests this. Perhaps part of the way is to be attracted to inflamed tissue," said Perkins. "Clearly enough protection has been developed to withstand this environment, although there may be high concentrations of bleach."

Researchers found that TlpD-like proteins from Salmonella enterica and Escherichia coli can also detect bleach -sensing may be a hitherto unrecognized phenomenon of many types of bacteria.

The research could eventually lead to new therapies that interfere with the ability of harmful bacteria to capture their environment and have implications for reducing antibiotic resistance.

Typically clinically used antibiotics today kill or prevent the division of bacteria by targeting things like the bacterial cell wall. As a result, bacteria are being subjected to the selective pressure to develop resistance to these types of drugs in order to survive.

In the case of Helicobacter pylori approximately 30 percent of infections are resistant to antibiotic treatments. With a deeper understanding of the mechanisms of action, Guillemin said, researchers could then develop more effective ways to combat bacteria.

"It may be that bacteria exert less selective pressure to overcome a drug that will do them justice," Guillemin said. "There will be a pandemic of antibiotic-resistant bacteria by 2050, so there is an urgent need to think about new strategies."


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Further information:
Arden Perkins et al., Helicobacter pylori, senses bleach (HOCl) as a chemoattractant using a cytosolic chemoreceptor, PLOS Biology (2019). DOI: 10.1371 / journal.pbio.3000395

Provided by
University of Oregon




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New research shows that a human stomach pathogen is attracted to bleaching agents (2019, August 29)
retrieved on August 29, 2019
from https://phys.org/news/2019-08-reveals-human-stomach-pathogen.html

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