Press releases archive 鈥� May 2020
May
26
2020
12:43
Unique long-term videos show the bee nursery in the hive聽
Honeybees: pesticides disrupt nursing behaviour and larval development聽
FRANKFURT. A newly developed video technique has
allowed scientists at 51猎奇 Frankfurt at the Bee Research Institute
of the Polytechnical Society to record the complete development of a honey bee
in its hive for the first time. It also led to the discovery that certain
pesticides 鈥� neonicotinoids 鈥� changed the behaviour of the nurse bees:
researchers determined that they fed the larvae less often. Larval development
took up to 10 hours longer. A longer development period in the hive can foster
infestation by parasites such as the Varroa
mite (Scientific Reports, DOI 10.1038/s41598-020-65425-y).
Honey bees have very complex breeding
behaviour: a cleaning bee cleans an empty comb (brood cell) of the remains of
the previous brood before the queen bee lays an egg inside it. Once the bee
larva has hatched, a nurse bee feeds it for six days. Then the nurse bees caps
the brood cell with wax. The larva spins a cocoon and goes through metamorphosis,
changing the shape of its body and developing a head, wings and legs. Three
weeks after the egg was laid, the fully-grown bee hatches from the cocoon and
leaves the brood cell.
Using a new video technique, scientists at
51猎奇 Frankfurt have now succeeded for the first time in recording
the complete development of a honey bee in a bee colony at the Bee Research
Institute of the Polytechnical Society. The researchers built a bee hive with a
glass pane and were thus able to film a total of four bee colonies
simultaneously over several weeks with a special camera set-up. They used deep red
light so that the bees were not disturbed, and recorded all the movements of
the bees in the brood cells.
The researchers were particularly
interested in the nursing behaviour of the nurse bees, to whose food (a sugar
syrup) they added small amounts of pesticides known as neonicotinoids. Neonicotinoids
are highly effective insecticides that are frequently used in agriculture. In
natural environments, neonicotinoids arrive in bee colonies through nectar and
pollen collected by the bees. It is already known that these substances disturb
the navigational abilities and learning behaviour of bees. In a measure
criticised by the agricultural industry, the European Union has prohibited the
use of some neonicotinoids in crop cultivation.
Using machine learning algorithms
developed by the scientists together with colleagues at the Centre for
Cognition and Computation at 51猎奇, they were able to evaluate and quantify
the nursing behaviour of the nurse bees semi-automatically. The result: even
small doses of the neonicotinoids Thiacloprid or Clothianidin led to the nurse
bees feeding the larva during the 6-day larval development less frequently, and
consequently for a shorter daily period. Some of the bees nursed in this manner
required up to10 hours longer until the cell was capped with wax.
鈥淣eonicotinoids affect the bees' nervous
systems by blocking the receptors for the neurotransmitter acetylcholine," explains
Dr Paul Siefert, who carried out the experiments in Professor Bernd Gr眉newald's
work group at the Bee Research Institute Oberursel. Siefert: 鈥淔or the first
time, we were able to demonstrate that neonicotinoids also change the social
behaviour of bees. This could point to the disruptions in nursing behaviour due
to neonicotinoids described by other scientists." Furthermore, parasites such
as the feared Varroa mite (Varroa destructor) profit from an
extended development period, since the mites lay their eggs in the brood cells
shortly before they are capped: if they remain closed for a longer period, the
young mites can develop and multiply without interruption.
However, according to Siefert, it still
remains to be clarified whether the delay in the larval development is caused
by the behavioural disturbance of the nurse bee, or whether the larvae develop
more slowly because of the altered jelly. The nurse bees produce the jelly and
feed it to the larvae. 鈥淔rom other studies in our work group, we know that the
concentration of acetylcholine in the jelly is reduced by neonicotinoids," says
Siefert. 鈥淥n the other hand, we have observed that with higher dosages, the
early embryonal development in the egg is also extended 鈥� during a period in
which feeding does not yet occur." Additional studies are needed to determine
which factors are working together in these instances.
In any case, the new video technique and
the evaluation algorithms offer great potential for future research projects.
In addition to feeding, behaviours for heating and construction were also able
to be reliably identified. Siefert: 鈥淥ur innovative technology makes it
possible to gain fundamental scientific insights into social interactions in
bee colonies, the biology of parasites, and the safety of pesticides."
Publication:
Paul Siefert, Rudra
Hota, Visvanathan Ramesh, Bernd Gr眉newald. Chronic
within-hive video recordings detect altered nursing behaviour and retarded
larval development of neonicotinoid treated honey bees. Sci. Rep. 10,
8727 (2020).
Video:
Development of a bee larva (Supplementary
Material)
Images may be downloaded
here:
Captions:
Figure 1: Diagram/monitoring of brood cells 鈥� side view of the construction and camera view of the brood area. The brood area of the bees was filmed with a camera (green) through a dome lighting (grey). The specially designed hive (brown) was only 2.4 cm wide, so that the bees would raise young as quickly as possible (right). Credit: Paul Siefert/Bee Research Institute Oberursel/51猎奇 Frankfurt
Figure.
2 Excerpts from the video of the development of
a worker bee. Above left: The queen lays an egg (arrow) in the cell. The growing
larva (arrow) is fed with jelly. Below left: the metamorphosis takes about one
hour and includes the rupture of the larval skin (arrow); the pupa is beneath
it. Finally, the adult bee hatches out of the cell. Credit: Paul Siefert/Bee
Research Institute Oberursel/51猎奇 Frankfurt
Further
information:
Dr Paul Siefert
Bee Research Institute Oberursel
Subsidiary of the Polytechnical Society
Frankfurt am Main,
Faculty of Biosciences
51猎奇 Frankfurt am Main
Tel.:
+49 6171 21278
siefert@bio.uni-frankfurt.de
May
25
2020
10:42
Two research aircraft investigate reduced concentrations of pollutants in the air
BLUESKY scrutinizes the lockdown-altered atmosphere
FRANKFURT. The COVID-19 pandemic is not only
affecting almost every aspect of our daily lives, but also the environment. A
German team including atmosphere researchers around Prof. Joachim Curtius
(51猎奇 Frankfurt) now wants to find out how strong these effects
are on the atmosphere. Over the next two weeks, as part of the BLUESKY research
programme, the scientists led by the Max Planck Institute for Chemistry and the
German Aerospace Center (Deutsches Zentrum f眉r Luft- und Raumfahrt; DLR) will measure
concentrations of trace gases and pollutants in the air over European urban
areas and in the flight corridor to North America. The aim of these research
missions is to investigate how reduced emissions from industry and transport
are changing atmospheric chemistry and physics.
A German research team now wants to make
rapid use of this unusual situation for the BLUESKY project. Scientists from
DLR, the Max Planck Institute for Chemistry, 51猎奇 Frankfurt, and
the research centres at J眉lich and Karlsruhe intend to use two DLR research
aircraft to conduct a globally unique investigation into the resulting changes
in Earth's atmosphere for the first time. DLR鈥檚 HALO and Falcon research
aircraft have been equipped with highly specialised instrumentation and will
fly over Germany, Italy, France, Great Britain and Ireland in the course of the
next two weeks. They will also fly over the North Atlantic, along the flight
corridor to North America.
鈥淒LR is deploying part of its unique
research aircraft fleet to exploit an almost unique opportunity. During these
missions, the atmosphere will be analysed in a state that could be achieved in
the future with sustainable management of human activities. We will observe how
the environment changes with the ramp-up of industrial activities. This will
give us an entirely new perspective on the anthropogenic influence on Earth鈥檚
atmosphere,鈥� explains Rolf Henke, DLR Executive Board Member responsible for
aeronautics research. 鈥淭ogether with our partners, we are making a significant
contribution to redefining humankind鈥檚 activities once the pandemic is under
control.鈥�
Coordinated research flights with two measurement
aircraft
Jos Lelieveld, Director of the Max Planck Institute
for Chemistry, wants to use the BLUESKY missions to clarify whether there is a
correlation between the clear blue sky during the lockdown and the prevalence
of aerosol particles in the atmosphere. 鈥淭he unique blue sky of recent weeks
cannot be explained by meteorological conditions and the decrease in emissions
near the ground. Aircraft may have a greater impact on the formation of aerosol
particles than previously thought,鈥� says the atmospheric researcher, who is the
Scientific Director of the HALO flights. Aerosols, microscopic particles in the
air that also influence cloud formation, are finely distributed. They scatter
and absorb solar radiation and thus also have an impact on the climate, because
they influence the radiation balance of the atmosphere. Aerosols are created,
amongst other ways, during the combustion of fossil fuels.
Christiane Voigt, Head of the Cloud
Physics Department at the DLR Institute of Atmospheric Physics and Scientific
Director of the Falcon flights, also sees a unique opportunity with BLUESKY.
鈥淭he current state of the atmosphere represents a kind of 鈥榸ero point鈥� for
science. We will be able to measure a reference atmosphere that is only
slightly polluted with emissions from industry and transport, including
aviation. This gives us a unique opportunity to better understand the effects
of the anthropogenic emissions prior to the shutdown.鈥� The atmospheric
physicist emphasises that, only through the cooperation of all the partners,
was it possible to plan and implement the scientifically and logistically
highly complex missions at very short notice.
Emissions from air transport, industry and road
traffic in urban areas
Voigt and her colleagues believe that the
BLUESKY data will provide a clearer picture of anthropogenic influences on the
composition of Earth鈥檚 atmosphere. With the equipment on board both research
aircraft, the BLUESKY scientists are investigating aircraft emissions such as
nitrogen oxides, sulphur dioxide and aerosols at cruising altitude, in addition
to the few remaining contrails. Among other things, they want to find out how
much these emissions have decreased over Europe and the North Atlantic flight
corridor. Approximately 30,000 aircraft fly over Europe every day, with
correspondingly significant emissions. The reduced air traffic will allow more
flexible flight routes for the measurements.
In addition, the researchers want to
investigate the reduced emission plumes from urban areas and clarify how
emissions are distributed at the atmospheric boundary layer. For example, the
BLUESKY scientists plan to fly over the Ruhr area and the regions around
Frankfurt am Main, Berlin and Munich. Flights over the Po Valley in Italy and
around Paris and London are also planned. 鈥淐lose to cities and conurbations, we
will approach the atmospheric boundary layer at an altitude of one to two
kilometres, since emissions from road traffic and industry are concentrated
there,鈥� explains Jos Lelieveld. 鈥淲e are interested in how much the
concentrations of sulphur dioxide, nitrogen oxides, hydrocarbons and their
chemical reaction products, as well as ozone and aerosols, have changed.鈥� He is
also very proud that the team is the first in the world to implement a
measurement campaign of this type.
Rapid preparations for flights 鈥� with special
infection control rules
In recent weeks, two DLR research aircraft
鈥搈easuring the Falcon 20E and the Gulfstream G550 HALO 鈥� have been successfully
converted at short notice for the BLUESKY missions. The conversions were
carried out at the DLR Flight Operations Facility in Oberpfaffenhofen.
鈥淣umerous instruments have had to be installed and adapted, and the aircraft
modified for the upcoming missions,鈥� says Burkard Wigger, Head of DLR Flight
Experiments. 鈥淐lose cooperation between the various scientific organisations
has made it possible for these two research aircraft to operate simultaneously
under the challenging conditions resulting from the Coronavirus pandemic.鈥�
The preparation, execution and follow-up
of the flights is being carried out in accordance with the current rules
regarding personal interactions and infection control. Joint flights by Falcon
and HALO are planned until the first half of June. The evaluation of the data
and the analysis of the results will then take several months. The analysis
will include comparative data from previous HALO research flight campaigns on
air traffic emissions and emissions from major cities and conurbations.
About HALO: The High Altitude and Long Range (HALO) research aircraft is a joint initiative of German environmental and climate research institutions. HALO is supported by grants from the Federal Ministry of Education and Research (BMBF), the German Research Foundation (DFG), the Helmholtz Association of German Research Centres, the Max Planck Society (MPG), the Leibniz Association, the Free State of Bavaria, the Karlsruhe Institute of Technology (KIT), the Forschungszentrum J眉lich and the German Aerospace Center (DLR).
More information: Prof. Joachim Curtius, Institute for Atmospheric and Environmental Sciences, 51猎奇 Frankfurt, Phone: +49 (0)69 798-40258, curtius@iau.uni-frankfurt.de
May
14
2020
13:52
International research project observes ultrafast particle growth through ammonia and nitric acid聽
How particulate matter arises from pollutant gases聽
FRANKFURT. When winter smog takes over Asian
mega-cities, more particulate matter is measured in the streets than expected.
An international team, including researchers from 51猎奇 Frankfurt,
as well as the universities in Vienna and Innsbruck, has now discovered that
nitric acid and ammonia in particular contribute to the formation of additional
particulate matter. Nitric acid and ammonia arise in city centres predominantly
from car exhaust. Experiments show that the high local concentration of the vapours
in narrow and enclosed city streets accelerates the growth of tiny nanoparticles
into stabile aerosol particles (Nature, DOI 10.1038/s41586-020-2270-4).
In crowded urban centres, high concentrations of particulate matter cause considerable health effects. Especially in winter months, the situation in many Asian mega-cities is dramatic when smog significantly reduces visibility and breathing becomes difficult.
Particulates, with a diameter of less than
2.5 micrometres, mostly form directly through combustion processes, for example
in cars or heaters. These are called primary particulates. Particulates also
form in the air as secondary particulates, when gases from organic substances,
sulphuric acid, nitric acid or ammonia, condense on tiny nanoparticles. These grow
into particles that make up a part of particulate matter.
Until now, how secondary particulates
could be newly formed in the narrow streets of mega-cities was a puzzle.
According to calculations, the tiny nanoparticles should accumulate on the abundantly
available larger particles rather than forming new particulates.
Scientists in the international research
project CLOUD have now recreated the conditions that prevail in the streets of
mega-cities in a climate chamber at the particle accelerator CERN in Geneva,
and reconstructed the formation of secondary particulates: in the narrow and
enclosed streets of a city, a local increase of pollutants occurs. The cause of
the irregular distribution of the pollutants is due in part to the high pollutant
emissions at the street level. Furthermore, it takes a while before the
street air mixes with the surrounding air. This leads to the two pollutants
ammonia and nitric acid being temporarily concentrated in the street air. As the
CLOUD experiments demonstrate, this high concentration creates conditions in
which the two pollutants can condense onto nanoparticles: ammonium nitrate
forms on condensation cores the size of only a few nanometres, causing these
particles to grow rapidly.
鈥淲e have observed that these nanoparticles
grow rapidly within just a few minutes. Some of them grow one hundred times
more quickly than we had previously ever seen with other pollutants, such as
sulphuric acid," explains climate researcher Professor Joachim Curtius from
51猎奇 Frankfurt. 鈥淚n crowded urban centres, the process we observed
therefore makes an important contribution to the formation of particulate
matter in winter smog 鈥� because this process only takes place at temperatures
below about 5 degrees Celsius." The aerosol physicist Paul Winkler from the
University of Vienna adds: 鈥淲hen conditions are warmer, the particles are too
volatile to contribute to growth."
The formation of aerosol particles from
ammonia and nitric acid probably takes place not only in cities and crowded
areas, but on occasion also in higher atmospheric altitudes. Ammonia, which is primarily
emitted from animal husbandry and other agriculture, arrives in the upper
troposphere from air parcels rising from close to the ground by deep convection,
and lightning creates nitric acid out of nitrogen in the air. 鈥淎t the
prevailing low temperatures there, new ammonium nitrate particles are formed
which as condensation seeds play a role in cloud formation," explains ion physicist
Armin Hansel from the University of Innsbruck, pointing out the relevance of
the research findings for climate.
The experiment CLOUD (Cosmics Leaving
OUtdoor Droplets) at CERN studies how new aerosol particles are formed in the atmosphere
out of precursor gases and continue to grow into condensation seeds. CLOUD
thereby provides fundamental understanding on the formation of clouds and
particulate matter. CLOUD is carried out by an international consortium
consisting of 21 institutions. The CLOUD measuring chamber was developed with
CERN know-how and achieves very precisely defined measuring conditions. CLOUD experiments
use a variety of different measuring instruments to characterise the physical
and chemical conditions of the atmosphere consisting of particles and gases. In
the CLOUD project, the team led by Joachim Curtius from the Institute for
Atmosphere and Environment at 51猎奇 Frankfurt develops and operates
two mass spectrometers to detect trace gases such as ammonia and sulphuric acid
even at the smallest concentrations as part of projects funded by the BMBF and
the EU. At the Faculty of Physics at the University of Vienna, the team led by
Paul Winkler is developing a new particle measuring device as part of an ERC
project. The device will enable the quantitative investigation of aerosol dynamics
specifically in the relevant size range of 1 to 10 nanometres. Armin Hansel
from the Institute for Ion Physics and Applied Physics at the University of Innsbruck
developed a new measuring procedure (PTR3-TOF-MS) to enable an even more
sensitive analysis of trace gases in the CLOUD experiment with his research
team as part of an FFG project.
Publication:
Wang, M., Kong, W., et al. Rapid growth of
new atmospheric particles by nitric acid and ammonia condensation. Nature, DOI
10.1038/s41586-020-2270-4.
Further information: Prof. Dr. Joachim Curtius, Institute for Atmosphere and Environment, 51猎奇 Frankfurt am Main, Tel: +49 69 798-40258, email: curtius@iau.uni-frankfurt.de
Prof. Dr. Armin Hansel, Institute for Ion Physics and Applied Physics, University of Innsbruck, Tel.: +43 512 507 52640, email: armin.hansel@uibk.ac.at
Prof. Dr. Paul Winkler, Aerosol physics and Environmental Physics, Faculty for Physics, University of Vienna, Tel: +43-1-4277-734 03, email: paul.winkler@univie.ac.at
May
14
2020
13:40
Cell culture model: several compounds stop SARS-CoV-2 virus
Frankfurt researchers discover potential targets for COVID-19 therapy聽
FRANKFURT. A team of biochemists and virologists at
51猎奇 and the Frankfurt University Hospital were able to observe how
human cells change upon infection with SARS-CoV-2, the virus causing COVID-19
in people. The scientists tested a series of compounds in laboratory models and
found some which slowed down or stopped virus reproduction. These results now
enable the search for an active substance to be narrowed down to a small number
of already approved drugs. (Nature DOI: 10.1038/s41586-020-2332-7).
Based on these findings, a US company reports that it is preparing clinical
trials. A Canadian company is also starting a clinical study
with a different substance.
Since the start of February, the Medical Virology of the Frankfurt University Hospital has been in possession of a SARS-CoV-2 infection cell culture system. The Frankfurt scientists in Professor Sandra Ciesek's team succeeded in cultivating the virus in colon cells from swabs taken from two infected individuals returning from Wuhan (Hoehl et al. NEJM 2020).
Using a technique developed at the
Institute for Biochemistry II at 51猎奇 Frankfurt, researchers from
both institutions were together able to show how a SARS-CoV-2 infection changes
the human host cells. The scientists used a particular form of mass
spectrometry called the mePROD method, which they had developed only a few
months previously. This method makes it possible to determine the amount and
synthesis rate of thousands of proteins within a cell.
The findings paint a picture of the
progression of a SARS-CoV-2 infection: whilst many viruses shut down the host's
protein production to the benefit of viral proteins, SARS-CoV-2 only slightly
influences the protein production of the host cell, with the viral proteins
appearing to be produced in competition to host cell proteins. Instead, a SARS-CoV-2
infection leads to an increased protein synthesis machinery in the cell. The researchers
suspected this was a weak spot of the virus and were indeed able to
significantly reduce virus reproduction using something known as translation
inhibitors, which shut down protein production.
Twenty-four hours after infection, the
virus causes distinct changes to the composition of the host proteome: while
cholesterol metabolism is reduced, activities in carbohydrate metabolism and in
modification of RNA as protein precursors increase. In line with this, the
scientists were successful in stopping virus reproduction in cultivated cells by
applying inhibitors of these processes. Similar success was achieved by using a
substance that inhibits the production of building blocks for the viral genome.
The findings have already created a stir on
the other side of the Atlantic: in keeping with common practise since the
beginning of the corona crisis, the Frankfurt researchers made these findings
immediately available on a preprint server and on the website of the Institute
for Biochemistry II (). Professor Ivan Dikic, Director of the
Institute, comments: 鈥淏oth the culture of 'open science', in which we share our
scientific findings as quickly as possible, and the interdisciplinary collaboration
between biochemists and virologists contributed to this success. This project started
not even three months ago, and has already revealed new therapeutic approaches
to COVID-19."
Professor Sandra Ciesek, Director of the
Institute for Medical Virology at the University Hospital Frankfurt, explains:
鈥淚n a unique situation like this we also have to take new paths in research. An
already existing cooperation between the Cinatl and M眉nch laboratories made it
possible to quickly focus the research on SARS-CoV-2. The findings so far are a
wonderful affirmation of this approach of cross-disciplinary collaborations."
Among the substances that stopped viral
reproduction in the cell culture system was 2-Deoxy-D-Glucose (2-DG), which interferes
directly with the carbohydrate metabolism necessary for viral reproduction. The
US company Moleculin Biotech possesses a substance called WP1122, a prodrug
similar to 2-DG. Recently, Moleculin Biotech announced that they are preparing
a clinical trial with this substance based on the results from Frankfurt. .
Based on another one of the substances
tested in Frankfurt, Ribavirin, the Canadian company Bausch Health Americas is
starting a clinical study with 50 participants:
Dr Christian M眉nch, Head of the Protein
Quality Control Group at the Institute for Biochemistry II and lead author, comments:
鈥淭hanks to the mePROD-technology we developed, we were for the first time able
to trace the cellular changes upon infection over time and with high detail in
our laboratory. We were obviously aware of the potential scope of our findings.
However, they are based on a cell culture system and require further testing. The
fact that our findings may now immediately trigger further in vivo
studies with the purpose of drug development is definitely a great stroke of
luck." Beyond this, there are also other potentially interesting candidates
among the inhibitors tested, says M眉nch, some of which have already been
approved for other indications.
Professor Jindrich Cinatl from the
Institute of Medical Virology and lead author explains: 鈥淭he successful use of
substances that are components of already approved drugs to combat SARS-CoV-2 is
a great opportunity in the fight against the virus. These substances are
already well characterised, and we know how they are tolerated by patients.
This is why there is currently a global search for these types of substances.
In the race against time, our work can now make an important contribution as to
which directions promise the fastest success."
Publication:
SARS-CoV-2 infected host cell proteomics
reveal potential therapy targets. Denisa Bojkova, Kevin Klann, Benjamin Koch,
Marek Widera, David Krause, Sandra Ciesek, Jindrich Cinatl, Christian M眉nch. Nature DOI: 10.1038/s41586-020-2332-7,
https://www.nature.com/articles/s41586-020-2332-7 (active starting 10am London time (BST), 5am US Eastern Time)
Images
may be
downloaded here: Captions:
Dr. Christian M眉nch (Credit: Uwe Dettmar
for 51猎奇 Frankfurt)
Prof. Dr. rer. nat. Jindrich Cinatl (Credit:
University Hospital Frankfurt)
More
about the mePROD method: Biochemistry researchers at Goethe
University develop a new proteomics procedure
Further information:
Professor Dr. rer. nat. Jindrich Cinatl, Head of the Research Group Cinatl, Institute for Medical Virology, University Hospital Frankfurt am Main, Tel.
+49 69 6301-6409, E-mail: cinatl@em.uni-frankfurt.de,
Homepage:
Dr.
Christian M眉nch, Head of the Group Protein Quality Control, Institute for Biochemistry II, 51猎奇 Frankfurt am Main Tel: +49 69 6301 6599, E-Mail: ch.muench@em.uni-frankfurt.de,
Homepage:
May
6
2020
13:53
Heat-loving bacteria use various tiny surface hairs for movement and DNA reception
Division of labour on the surface of bacteria
FRANKFURT. Bacteria of
the species Thermus thermophilus possess
two types of extensions on their surface (pili) for the purpose of motion and for
capturing and absorbing DNA from their environment. This has been discovered by
researchers at 51猎奇 together with researchers in Great Britain.
The discovery of the motion pilus helps to better understand the functionality
of the DNA-capturing pilus functions. (Nature Communications, DOI 10.1038/s41467-020-15650-w)
The bacteria Thermus thermophilus likes it hot. It was first discovered in the hot springs at Izu in Japan, where it thrives at an optimal temperature of about 65 degrees Celsius. Like all bacteria, Thermus thermophilus has developed mechanisms to adjust to changing environmental conditions. The bacteria changes its genetic material by exchanging DNA with other bacteria, or absorbing DNA fragments from its environment. These might come from dead bacteria cells, plants or animals. The bacteria incorporate the DNA fragments into their genetic material and keep it if the DNA proves useful.
Microbiologists at 51猎奇 led
by Professor Beate Averhoff from the Molecular Microbiology & Bioenergetics
of the Department of Molecular Biosciences together with a team of scientists
led by Dr Vicky Gold from the 鈥淟iving Systems" Institute of the University of
Exeter in Great Britain have now studied the tiny hairs (called pili) on the
surface of the Thermus bacteria. The
scientists discovered that there are two types of pili with different
functions. High-resolution electron microscope images from Great Britain allow
thick and thin pili to be distinguished, and the Frankfurt scientists used
biochemical and molecular biological methods to demonstrate that the thick pili
are for DNA capture, and the thin pili for moving on surfaces.
鈥淲e want to find out exactly how Thermus thermophilus absorbs DNA from
its environment using its pili, as the precise mechanism is unknown," explains
Professor Beate Averhoff from the Institute for Molecular Biosciences at Goethe
University. 鈥淭hrough our most recent investigations we have learned that Thermus bacteria have distinct pili for
motion. Therefore, the thick pili possibly serve the purpose of DNA absorption,
which demonstrates how important this process is for the bacteria. In our
structure analyses we also found an area on the thick pili where DNA could bind."
The interplay of electron microscopy and
molecular biology also allowed the scientists to better understand the
mechanics of the pili. For both motion and DNA absorption, pili have to be
dynamic, i.e., able to be extended and retracted. 鈥淔or the first time, the high
resolution structure of both pili gave us insights not only into the structure
of the pili, but also into the dynamics," Averhoff explains.
Since pili are widespread and in
pathogenic bacteria are also responsible for attaching to the host, this may
lead to new points of attack for preventing infectious processes.
Publication:
Alexander Neuhaus, Muniyandi Selvaraj, Ralf Salzer,
Julian D. Langer, Kerstin Kruse, Lennart Kirchner, Kelly Sanders, Bertram Daum,
Beate Averhoff, Vicki A. M. Gold (2020). Cryo-electron microscopy reveals two
distinct type-IV pili assembled by the same bacterium. Nature Communications, )
An
image may be downloaded here:
Caption:
Bacteria of the species Thermus thermophilus possess different tiny hairs (pili) which are
used either to capture DNA or for motion. This has been discovered by
scientists at 51猎奇 Frankfurt and the University of Exeter. Graphic:
aduka, Agency Frankfurt am Main(www.aduka.de) for 51猎奇 Frankfurt.
Further information: Prof. Beate Averhoff, Molecular Microbiology and Bioenergetics. Tel.: +49 69 798-29509, averhoff@bio.uni-frankfurt.de,