Press releases archive 鈥� June 2020
Jun
24
2020
11:37
Mystery about the cancer drug nelarabine solved after decades
Treating leukaemia more effectively聽
FRANKFURT. Acute
lymphoblastic leukaemia (ALL) is the most common kind of cancer in children.
T-ALL, a subtype that resembles T-lymphocytes, can be treated successfully with
the drug nelarabine. The drug has not been successful, however, with B-ALL, a
subtype resembling B-lymphocytes. Since the 1980s, oncologists have been puzzled
as to the cause of this difference. Now, an international research team headed
by 51猎奇 and the University of Kent has discovered the reason:
B-ALL cells contain the enzyme SAMHD1, which deactivates the drug.
In the current issue of 鈥淐ommunications
Biology", Professor Jindrich Cinatl from the Institute for Medical Virology at
51猎奇 and Professor Martin Michaelis from the School of Biosciences
at the University of Kent report on their investigations with nelarabine on
different cell lines. 鈥淣elarabine is the precursor of the drug, a prodrug, that
does not become effective until it is combined with three phosphate groups in
the leukaemia cell," explains Professor Cinatl. 鈥淚n studies of various ALL cell
lines and leukaemia cells from ALL patients, we have been able to demonstrate
that the enzyme SAMHD1 splits the phosphate groups off so that the medicine loses
its effect." Because B-ALL cells contain more SAMHD1 than T-ALL cells,
nelarabine is less effective with B-ALL.
These results could improve the treatment
of ALL in the future. In rare cases, B-ALL cells contain very little SAMHD1 so
that treatment with nelarabine would be possible. On the contrary, there are
also rare cases of T-ALL exhibiting a lot of SAMHD1. In such cases, the
otherwise effective nelarabine would not be the right medication. Professor
Michaelis observes: 鈥淪AMHD1 is thus a biomarker that allows us to better adapt
treatment with nelarabine to the individual situation of ALL patients."
Tamara Rothenburger, whose doctoral
dissertation was funded by the association 鈥淗ilfe f眉r krebskranke Kinder
Frankfurt e.V鈥�, is satisfied when she looks back at her research. 鈥淚 hope that
many children with leukaemia will benefit from the results." The research was
also supported by the Frankfurt Stiftung f眉r krebskranke Kinder. Additional
members of the research group are Ludwig-Maximilians-Universit盲t Munich, and
University College London.
Publication:
Tamara Rothenburger, Katie-May McLaughlin,
Tobias Herold, Constanze Schneider, Thomas Oellerich, Florian Rothweiler,
Andrew Feber, Tim R. Fenton, Mark N. Wass, Oliver T. Keppler, Martin Michaelis,
Jindrich Cinatl. SAMHD1 is a key
regulator of the lineage-specific response of acute lymphoblastic leukaemias to
nelarabine, in: Communications Biology, DOI
10.1038/s42003-020-1052-8,
Further
information:
Prof. Dr. rer. nat. Jindrich Cinatl
Institute for Medical Virology
University Hospital Frankfurt
Tel.: +49 69 6301-6409
E-mail: cinatl@em.uni-frankfurt.de
Jun
22
2020
13:58
Researchers from Frankfurt produce tsetse attractants in yeast to contain sleeping sickness
Tsetse flytraps: Biotechnology for Africa鈥檚 rural population
FRANKFURT. Because the tsetse fly can transmit
sleeping sickness, it is commonly combatted with insecticides or caught in
traps. Bioscientists at 51猎奇 have now developed a method for
producing the attractants for the traps in a biotechnological procedure. The Frankfurt
scientists hope that in the future, the attractants can then be produced
locally in rural areas of Africa at low cost (Scientific Reports, DOI:
10.1038/s41598-020-66997-5).
The tsetse fly occurs in large regions of sub-Saharan
Africa. The flies feed on human and animal blood, transmitting trypanosoma in
the process 鈥� small, single-cell organisms that use the flies as intermediate
host and cause a dangerous inflammation of the lymph and nervous system in both
animals and humans. There is no vaccination for this sleeping sickness;
untreated, it usually ends in death. In agriculture, particularly cattle
breeding, sleeping sickness 鈥� or trypanosomiasis 鈥� causes enormous damages in
the form of sick and dead animals.
In addition to the use of insecticides,
the insects are also caught in traps. The attractants used include substances
that also occur in cattle urine and which attract tsetse flies. These
substances (3-ethylphenol and 3-propylphenol, or 3-EP and 3-PP for short) are
synthesized out of oil derivatives or also extracts from cashew nut shells
through chemical processes. However, both processes are complex and neither
practical nor affordable for rural communities in Africa.
In the LOEWE collaborative research
project MegaSyn, molecular biologists at 51猎奇 have now succeeded
in producing 3-EP and 3-PP in genetically modified brewer鈥檚 yeast (Saccharomyces cerevisiae). They used a
yeast strain into which they had previously introduced a new metabolic pathway,
and changed its sugar metabolism. This enabled the yeasts to produce similarly
high concentrations of 3-EP and 3-PP as those which occur in cow urine.
Doctoral student Julia Hitschler from the Institute
for Molecular Biosciences at 51猎奇 explains: 鈥淥ur yeasts could
ideally grow in Africa in nutrient solutions on the basis of plant waste
products, food rests or fodder rests. This would make production of the
attractant almost cost-free. We are currently looking for partners to help us test
our yeasts locally and provide them to the local population.鈥�
The potential for the new yeasts go beyond
the tsetse attractants, add Professor Eckhard Boles, who heads the project. In
the future, other substances that have been previously won through oil or coal
could be produced through the new yeasts: 鈥淥ur yeasts could be developed to
produce other alkylphenols besides 3-EP and 3-PP. These alkylphenols could be
used for the production of lubricant additives or surface-active substances in
cleaning agents.鈥�
Publication:
Julia Hitschler, Martin Grininger, Eckhard
Boles: Substrate promiscuity of
polyketide synthase enables production of tsetse fly attractants 3-ethylphenol
and 3-propylphenol by engineering precursor supply in yeast. Scientific
Reports,
Further
information:
Prof. Dr. Eckhard Boles
Institute for Molecular Biosciences
51猎奇 Frankfurt
Tel:
+49 69 798 29513
e.boles@bio.uni-frankfurt.de
Jun
17
2020
16:39
A game theoretical study shows that envy coupled with competition divides society into an upper and lower class
Envy divides society聽
FRANKFURT. Can class differences come about endogenously, i.e. independent of birth and education? Professor Claudius Gros from the Institute for Theoretical Physics at 51猎奇 pursued this issue in a game theoretical study. He was able to show that the basic human need to compare oneself with others may be the root cause of the formation of social classes.
It's generally recognized that differences
in background and education cement class differences. It is less clear when and
under what circumstances individual psychological forces can drive an initially
homogenous social group apart and ultimately divide it. Claudius Gros,
professor for theoretical physics at 51猎奇, investigated this
question in a mathematical precise way using game theory methods. 鈥淚n the
study, societies of agents 鈥� acting individuals 鈥� are simulated within game
theory, which means that everybody optimises her/his success according to
predetermined rules. I wanted to find out whether social differences can emerge
on their own if no one starts off with advantages 鈥� that is, when all actors
have the same skills and opportunity," the physicist explains.
The study is based on the assumption that
there are things in every society that are coveted but limited 鈥� such as jobs,
social contacts and positions of power. An inequality is created if the top
position is already occupied and someone must therefore accept the second-best
job 鈥� but not, however, a societal division. With the help of mathematical
calculations Gros was able to demonstrate that envy, which arises from the need
to compare oneself with others, alters individual behaviour and consequently
the agents' strategies in characteristic ways. As a result of this changed
behaviour, two strictly separate social classes arise.
Game theory provides the mathematical
tools necessary for the modelling of decision situations with several
participants, as in Gros' study. In general, constellations in which the
decision strategies of the individual actors mutually influence each other are
particularly revealing. The success of the individual depends then not only on
his or her own actions, but on others' actions as well, which is typical of
both economic and social contexts. Game theory is consequently firmly anchored
in the economy. The stability condition of game theory, the 鈥淣ash equilibrium",
is a concept developed by John Forbes Nash in his dissertation in 1950, using
the example of poker players. It states that in equilibrium no player has
anything to gain by changing their strategy if the other players do not change
theirs either. An individual only tries out new behaviour patterns if there is
a potential gain. Since this causal chain also applies to evolutionary
processes, the evolutionary and behavioural sciences regularly fall back on
game theoretical models, for example when researching animal behaviours such as
the migratory flight routes of birds, or their competition for nesting sites.
Even in an envy-induced class society
there is no incentive for an individual to change his or her strategy,
according to Gros. It is therefore Nash stable. In the divided envy society
there is a marked difference in income between the upper and lower class which
is the same for all members of each social class. Typical for the members of
the lower class is, according to Gros, that they spend their time on a series
of different activities, something game theory terms a 鈥渕ixed strategy".
Members of the upper class, however, concentrate on a single task, i.e., they
pursue a 鈥減ure strategy". It is also striking that the upper class can choose
between various options while the lower class only has access to a single mixed
strategy. 鈥淭he upper class is therefore individualistic, while agents in the
lower class are lost in the crowd, so to speak," the physicist sums up.
In Claudius Gros' model, whether an agent
lands in the upper or lower class is ultimately a matter of coincidence. It is
decided by the dynamics of competition, and not by origin. For his study, Gros
developed a new game theoretical model, the 鈥渟hopping trouble model" and worked
out a precise analytical solution. From
it, he derives that an envy-induced class society possesses characteristics
that are deemed universal in the theory of complex systems. The result is that
the class society is beyond political control to a certain degree. Political
decision-makers lose a portion of their options for control when society
spontaneously splits into social classes. In addition, Gros' model demonstrates
that envy has a stronger effect when the competition for limited resources is
stronger. 鈥淭his game theoretical insight could be of central significance. Even
an 'ideal society' cannot be stably maintained in the long term 鈥� which
ultimately makes the striving for a communistic society seem unrealistic," the
scientist remarks.
Publication: Claudius Gros, 鈥濻elf induced class stratification in competitive societies of agents: Nash stability in the presence of envy鈥�, Royal Society Open Science , Vol 7, 200411 (2020).
Link:
Further information: Professor Claudius Gros, Institute for
Theoretical Physics, Riedberg Campus, E-Mail gros07@itp.uni-frankfurt.de
Jun
15
2020
13:57
Frankfurt researchers deliver experimental proof for a 90 year-old theory
Atomic physics: radiation pressure with recoil
FRANKFURT. Light exerts a certain amount of pressure onto a body:
sun sails could thus power space probes in the future. However, when light
particles (photons) hit an individual molecule and knock out an electron, the
molecule flies toward the light source. Atomic physicists at 51猎奇
have now observed this for the first time, confirming a 90 year-old theory.
As
early as the 16th century, the great scholar Johannes Kepler
postulated that sunlight exerted a certain pressure, as the tail of the comets
he observed consistently pointed away from the sun. In 2010 the Japanese space
probe Ikaros used a sun sail for the first time in order to use the power of
sunlight to gain a little speed.
Physically and intuitively, the pressure
of light or radiation can be explained by the particle characteristic of light:
light particles (photons) strike the atoms of a body and transfer a portion of their
own momentum (mass times speed) onto that body, which
thus becomes faster.
However, when in the 20th
century physicists studied this momentum transfer in the laboratory during
experiments on photons of certain wavelengths which knocked individual
electrons out of atoms, they were met by a surprising phenomenon: the momentum of
the ejected electron was greater than that of the photon that struck it. This
is actually impossible 鈥� since Isaac Newton it has been known that within a
system, for every force there must exist an equal but opposite force: the
recoil, so to speak. For this reason, the Munich scientist Arnold Sommerfeld
concluded in 1930 that the additional momentum of the ejected electron must
come from the atom it left. This atom must fly in the opposite direction; in
other words, toward the light source. However, this was impossible to measure with
the instruments available at that time.
Ninety years later the physicists in the
team of doctoral student Sven Grundmann and Professor Reinhard D枚rner from the
Institute for Nuclear Physics have succeeded for the first time in measuring
this effect using the COLTRIMS reaction microscope developed at Goethe
University Frankfurt. To do so, they used X-rays at the accelerators DESY in
Hamburg and ESRF in French Grenoble, in order to knock electrons out of helium
and nitrogen molecules. They selected conditions that would require only one
photon per electron. In the COLTRIMS reaction microscope, they were able to
determine the momentum of the ejected electrons and the charged helium and
nitrogen atoms 鈥� which are called ions 鈥� with unprecedented precision.
Professor Reinhard D枚rner explains: 鈥淲e
were not only able to measure the ion鈥檚 momentum, but also see where it came
from 鈥� namely, from the recoil of the ejected electron. If photons in these
collision experiments have low energy, the photon momentum can be neglected for
theoretical modelling. With high photon energies, however, this leads to imprecision.
In our experiments, we have now succeeded in determining the energy threshold
for when the photon momentum may no longer be neglected. Our experimental breakthrough
allows us to now pose many more questions, such as what changes when the energy
is distributed between two or more photons.鈥�
Publication:
Sven Grundmann, Max Kircher, Isabel
Vela-Perez, Giammarco Nalin, Daniel Trabert, Nils Anders, Niklas Melzer, Jonas
Rist, Andreas Pier, Nico Strenger, Juliane Siebert, Philipp V. Demekhin, Lothar
Ph. H. Schmidt, Florian Trinter, Markus S. Sch枚ffler, Till Jahnke, and Reinhard
D枚rner: Observation of Photoion Backward
Emission in Photoionization of He and N2. Phys. Rev. Lett. 124, 233201
Further information:
Prof.
Dr. Reinhard D枚rner
Institute for Nuclear Physics
Tel. +49 69 798-47003
doerner@atom.uni-frankfurt.de
/
Jun
12
2020
15:01
51猎奇 physicists develop free covid-19 analysis website to compare the number of cases and deaths by country
Comparing covid-19 data worldwide with a click of the mouse聽聽
FRANKFURT. There is no lack of data on
global corona developments. But if you want to actively compare countries
yourself and relate case and death figures across countries, you can now get a
quick overview with just a few clicks 鈥� and gain surprising insights in the
process.
The new web service 鈥淕oethe Interactive
Covid-19 Analyzer鈥� which Fabian Schubert in the working group for the theory of
complex systems at the Institute for Theoretical Physics developed alongside
his dissertation is simple to use: go to the 鈥淕oethe Interactive Covid-19
Analyzer鈥� website, click on the countries and number of cases in questions, and
drag the curves over each other. Congruent? The answer is immediately visible.
In the same way 鈥� depending on the individual question - the daily number of
cases or deaths, or the total number of infected or deceased individuals can be
compared. The underlying data for countries from 鈥淎鈥� as in Afghanistan through
鈥淶鈥� as in Zimbabwe is provided by the known covid-19 databases of the European Centre
for Disease Control鈥� and the 鈥�.鈥�
鈥淥ur interactive tool allows researchers,
journalists and other interested parties to quickly gain an overview of
outbreak developments,鈥� explains Professor Claudius Gros, who studies the modelling
of covid-19 outbreaks himself at the Institute for Theoretical Physics, and who
as Schubert鈥檚 doctoral advisor encouraged him to develop the service tool.
Those who use the tool may also discover relationships that provide inspiration
for additional research on epidemic processes.
Gros, for example, was surprised that the
scaled trajectory curves of the case numbers from Germany and Spain 鈥渁re almost
identical, although the two countries pursued significantly different lockdown
measures.鈥� There are also interesting clues regarding the unexplained issue of
the number of unrecorded cases of corona infections. For Italy, the scaled
curve of covid-19 infections corresponds to the curve of corona deaths if the
daily case numbers are applied to the total numbers of the sick or the
deceased. 鈥淭his indicates that the unrecorded case numbers may not have changed
significantly over the course of the outbreak 鈥� even though testing increased.鈥�
The 鈥淕oethe Interactive Covid-19 Analyzer鈥�
from the Institute for Theoretical Physics offers numerous options for combining
data per mouse click. 鈥淭he page has only been live for a couple of days,鈥� says Gros. It therefore remains to be seen
how many researchers and other interested parties will use the new analytical
tool. The first scientists have already indicated interest, however. And the theoretical
physicist is certain: 鈥淭he website is certainly useful for the final papers and
doctoral dissertations on covid-19 that will soon be written. And also for
secondary school students who want to present a paper on corona.鈥�
The new analytic tool is hosted on the
webserver of the Institute for
Theoretical Physics, which is also providing the necessary technical support.
Website: Goethe Interactive Covid-19 Analyzer:
Publication: Claudius Gros, Roser Valenti, Kilian Valenti, Daniel Gros, Strategies
for controlling the medical and socio-economic costs of the Corona pandemic (2020);
Further information: Prof. Dr. Claudius Gros, Institut f眉r Theoretische Physik, Campus Riedberg, E-Mail gros07@itp.uni-frankfurt.de