Bacterial trick: A kind of sponge that absorbs certain messengers

Date:
February 3, 2022
Source:
University of Wu"rzburg
Summary:
Bacteria are extremely resourceful when it comes to adapting to
a given environment. A team of researchers has now discovered
a new trick bacteria use: a kind of sponge that absorbs certain
messengers.



FULL STORY ========================================================================== Bacteria are extremely resourceful when it comes to adapting to a given environment. A team of researchers has now discovered a new trick bacteria
use: a kind of sponge that absorbs certain messengers.


==========================================================================
Each year, at least 1.27 million people die from an infection with
bacteria that are resistant to standard antibiotics, a study recently
published in the journal The Lancet reveals. The authors fear that this
number could rise to as many as ten million people by 2050.

This makes the hunt for new substances that are effective against
resistant bacterial strains more urgent than ever. A potential approach
focuses on programmable RNA-based antibiotics. However, this requires
an in-depth understanding of the key RNA-based signalling pathways and mechanisms during an infection.

New signalling pathways identified This is the subject of research at
the Institute for Molecular Infection Biology (IMIB) of the University
of Wu"rzburg and at the Helmholtz Institute for RNA-based Infection
Research. Researchers in the laboratory of Professor Jo"rg Vogel, who
holds the Chair of Molecular Infection Biology I at JMU and Managing
Director of the HIRI, have figured out new details of these signalling
pathways and mechanisms. They present the results of their study in the
latest issue of the journal Molecular Cell.

Gianluca Matera, a Ph.D. student at the IMIB, provides more information
on the background of the paper he co-authored with Jo"rg Vogel, saying:
"A lot of bacteria, such as Escherichia coli and Salmonella enterica,have
a cell envelope consisting of an outer and an inner membrane. The main
function of this envelope is to shield the bacteria from their environment
but it also has to be permeable for nutrients which the bacteria need
to thrive." A previously unknown player


========================================================================== Numerous RNA entities interact in order to manage which substances can
pass through the cell envelope and which are blocked at a given time, the latter allowing the bacteria to protect themselves against antibiotics,
for example.

The researchers have now identified a previously unknown protagonist
in the bacterium Salmonella enterica: an "RNA sponge." Such sponges
belong to the class of "small RNAs." The Wu"rzburg study shows that
the RNA sponge OppX mimics the actual binding target of a special sRNA,
the so-called MicF sRNA, in the bacterial outer membrane, intercepting
it before it reaches its destination. Or in other words, it absorbs it
like a sponge.

Communication of the membranes The MicF sRNA plays a crucial role in
the processes of the bacterial envelope.

"The outer and inner membrane of the bacterial envelope cannot work independently from one another. So there have to be mechanisms that enable
them to communicate with each other. Small non-coding RNAs, such as MicF,
are one class of such regulators," Gianluca Matera explains. Using a new technique developed at the Hebrew University of Jerusalem, the junior
scientist has now identified the interacting partners of all these sRNAs
in Salmonella - - comprehensively and in a single step.

The researchers are capable of describing the effect of this interception process in detail: "Normally, OppX increases membrane permeability by
boosting the expression of one of the main pores in the bacterial outer membrane," Matera specifies. This scientific name of this pore is OmpF.



==========================================================================
If the bacterium lacks the OppX sponge, its growth will be restricted, especially in a nutrient-poor environment. If, however, sufficient amounts
of OppX are available, the OmpF pores in the membrane also become more
active, increasing the uptake of nutrients if they are scarce.

Indirect impact on antibiotics The OmpF pores also assume a key function
when the bacteria are attacked by antibiotics: The substances use them
as their main points of entry into the cell. "Indirectly, OppX could
have an impact on antibiotic efficacy by boosting OmpF production and
thus the uptake of the antibiotic itself," Matera says.

OppX is the first known regulator of MicF activity -- the recently
published data even supports the assumption that OppX is the most
important, if not the only, sponge for the MicF sRNA. Therefore, knowing
it is crucial to fully understand the cellular activity of MicF according
to the authors of the study.

These new findings are based on studies of bacteria grown in vitro under laboratory conditions. The scientists believe that the next challenge
will be to extend these studies to more "realistic" conditions. The
first step in this direction has already been taken: "We are currently
decoding the RNA interactome of Salmonella in infected host cells,"
Jo"rg Vogel explains.

"Antibiotic resistance is one of the major health
threats of our time -- that's why our basic research
strives to contribute to the development of new therapeutics." ========================================================================== Story Source: Materials provided by University_of_Wu"rzburg. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gianluca Matera, Yael Altuvia, Milan Gerovac, Youssef El Mouali,
Hanah
Margalit, Jo"rg Vogel. Global RNA interactome of Salmonella
discovers a 5' UTR sponge for the MicF small RNA that connects
membrane permeability to transport capacity. Molecular Cell, 2022;
DOI: 10.1016/ j.molcel.2021.12.030 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220203103003.htm

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