Bacteria
act in groups to accomplish feats that are impossible to achieve if a single
bacterium acts alone. For example, pathogenic bacteria act collectively to synthesize
toxins to attack the host and to encase themselves in a shield that protects
them from the host immune system and allows them to resist antibiotic treatment.
To do this, bacteria communicate with each other with chemical “words", count
their numbers, and act in synchrony when they have sufficient cell numbers for
success. The award winners have discovered the dictionary and syntax underlying
bacterial communication, opening up new and unprecedented opportunities to
fight bacterial infections.
FRANKFURT am MAIN. Two American scientists,
Bonnie L. Bassler and Michael R. Silverman, receive the 2021 Paul Ehrlich
and Ludwig Darmstaedter Prize, which is endowed with 120,000 €. Bassler is
Professor at Princeton University and a Howard Hughes Medical Institute Investigator,
Michael R. Silverman is Emeritus Professor of the Agouron Institute in La
Jolla. The two researchers are honoured for their ground-breaking discoveries concerning
bacterial "quorum sensing", which refers to sophisticated systems of
cell-to-cell communication that bacteria use to coordinate group behaviours.
The award ceremony in St. Paul's Church, which is traditionally held on March
14, Paul Ehrlich's birthday, has been postponed due to the Coronavirus
pandemic. Instead, Bassler and Silverman will receive the award at the ceremony
in 2022.
"Silverman and Bassler have shown that, as
for multicellular organisms, collective behaviour is the rule among bacteria, rather
than the exception," wrote the Scientific Council in substantiating its
decision. "Bacteria talk to each other, they eavesdrop on other bacteria, and
they may even join forces. But: This ubiquitous chitchat, whose molecular
underpinnings were discovered by Bassler and Silverman, also represents a
previously unappreciated Achilles' heel in combating harmful microbes. Instead
of killing bacteria with antibiotics, substances may be developed that
interfere with bacterial communication effectively reducing their collective fitness.
The prize-winners' research thus has considerable relevance for medicine".
Bacteria are extremely communicative. They send
and receive chemical messages to find out whether they are alone or if additional
members of their or other species are present in the vicinal community. To take
a census of cell numbers, bacteria produce and release chemical signal
molecules that accumulate in step with increasing cell numbers. When a
threshold level of the chemical signal is achieved, the bacteria detect its
presence. In response to it, in unison, bacteria undertake behaviours that are
only productive when carried out in synchrony by the group, but not when
enacted by a single bacterium acting in isolation. This chemical
communication process is called quorum sensing and it controls hundreds of
collective activities across the bacterial kingdom.
In the 1980s, Silverman discovered the first quorum-sensing
circuit in the bioluminescent marine bacterium Vibrio fischeri. He identified
the genes and proteins enabling production and detection of the extracellular
signal molecule. He defined how the components functioned to promote collective
behaviour. In the case of Vibrio fischeri, group-wide behaviour
is the production of blue-green bioluminescence. Today, we know that quorum
sensing is the norm in the bacterial world. Indeed, there are thousands of
bacterial species that possess genes nearly identical to those discovered by
Silverman. In all of these cases, these components allow bacteria to engage in
group behaviours.
In the early 1990s, Bonnie
Bassler proved that bacteria were “multilingual" and that they conversed with
multiple chemical signal molecules. One communication molecule that Bassler
discovered and named autoinducer- 2 enables bacteria to communicate across species
boundaries. She went on to demonstrate that bacteria use
quorum-sensing-mediated communication to differentiate self from
other, showing that a sophisticated trait thought to be the purview of higher
organisms, in fact, evolved in bacteria billions of years ago. In recent years,
Bassler has shown that quorum sensing transcends kingdom boundaries as viruses
and host cells, including human cells, engage in this ubiquitous chit-chat. She
and other researchers also demonstrated that pathogenic bacteria rely on quorum
sensing to be virulent. Bassler developed anti-quorum-sensing strategies that,
in animal models, halt infection from bacterial pathogens of global
significance.
“The full significance of the discoveries of
the two laureates for microbiology and medicine has only recently been
recognized," says Professor Thomas Boehm, Director at the Max Planck
Institute for Immunobiology and Epigenetic and Chairman of the Scientific
Council. "Decades of meticulous and painstaking work, showed that essentially
all bacteria master the art of cell-to-cell communication," says Boehm.
"What began with work on Vibrio fischeri and Vibro harveyi led
to a fundamental change in perspective in bacteriology, and now opens up new and
unprecedented opportunities in dealing with antibiotic resistance".
Short biography Professor Dr.
Bonnie L. Bassler Ph.D. (58).
Bonnie Bassler is a microbiologist. She studied
biochemistry at the University of California at Davis and received her Ph.D.
from the Johns Hopkins University in Baltimore. She joined the laboratory of
Michael Silverman at the Agouron Institute in La Jolla as a postdoctoral fellow
in 1990. She has been at Princeton University since 1994. Bonnie Bassler is a
member of the National Academy of Sciences, the National Academy of Medicine,
and the Royal Society. She is a researcher at the Howard Hughes Medical
Institute and Squibb Professor and Chair of the Department of Molecular Biology
at Princeton University. President Obama appointed her to a six-year term on
the United States National Science Board. She has received more than twenty prestigious
national and international awards.
Short biography Professor
Michael R. Silverman, Ph.D. (77).
Michael Silverman is a microbiologist. He
studied chemistry and bacteriology at the University of Nebraska at Lincoln and
received his Ph.D. in 1972 from the University of California at San Diego.
During the period from 1972-1982, Silverman made seminal contributions to the
understanding of bacterial motility and chemotaxis. From 1982 until his
retirement, he worked at the Agouron Institute in La Jolla, of which he is a
co-founder.
The Paul Ehrlich and Ludwig
Darmstaedter Prize
The Paul Ehrlich and Ludwig Darmstaedter Prize
is traditionally awarded on Paul Ehrlich's birthday, March 14, in the
Paulskirche, Frankfurt. It honors scientists who have made significant
contributions in Paul Ehrlich's field of research, in particular immunology,
cancer research, microbiology, and chemotherapy. The Prize, which has been
awarded since 1952, is financed by the German Federal Ministry of Health, the
State of Hesse, the German association of research-based pharmaceutical company
vfa e.V. and specially earmarked donations from the following companies,
foundations and organizations: Else Kröner-Fresenius-Stiftung, Sanofi-Aventis
Deutschland GmbH, C.H. Boehringer Pharma GmbH & Co. KG, Biotest AG, Hans und Wolfgang
Schleussner-Stiftung, Fresenius SE & Co. KGaA, F. Hoffmann-LaRoche Ltd.,
Grünenthal GmbH, Janssen-Cilag GmbH, Merck KGaA, Bayer AG, Holtzbrinck
Publishing Group, AbbVie Deutschland GmbH & Co. KG, die
Baden-Württembergische Bank, B. Metzler seel. Sohn & Co. and
Goethe-Universität. The prizewinners
are selected by the Scientific Council of the Paul Ehrlich Foundation.
The
Paul Ehrlich Foundation
The
Paul Ehrlich Foundation is a legally dependent foundation which is managed in a
fiduciary capacity by the Association of Friends and Sponsors of the Goethe
University, Frankfurt. The Honorary Chairman of the Foundation, which was
established by Hedwig Ehrlich in 1929, is Professor Dr. Katja Becker, president
of the German Research Foundation, who also appoints the elected members of the
Scientific Council and the Board of Trustees. The Chairman of the Scientific
Council is Professor Thomas Boehm, Director at the Max Planck Institute of
Immunobiology and Epigenetics in Freiburg, the Chair of the Board of Trustees
is Professor Dr. Jochen Maas, Head of Research and Development and Member of
the Management Board, Sanofi-Aventis Deutschland GmbH. Professor Wilhelm
Bender, in his function as Chair of the Association of Friends and Sponsors of the
Goethe University, is Member of the Scientific Council. The President of the Goethe University is at the same time a member of
the Board of Trustees.
Further
information:
You can obtain selected
publications, the list of publications and a photograph of the laureate from
Dr. Hildegard Kaulen, phone: +49 (0)6122/52718, email: h.k@kaulen-wissenschaft.de and at www.paul-ehrlich-stiftung.de
Background on the
award of the 2021 Paul Ehrlich and Ludwig Darmstaedter Prize to Professor
Bonnie L. Bassler, Ph.D. and Professor Michael R. Silverman, Ph.D.