PULS/CE 27
Photo: Anna Schroll
Public Understanding of Life Sciences / Chemical Ecology
Newsletter May 2016
Cooperating bacteria isolate cheaters
Bacteria, which exchange amino acids with each other, stabilize their partnership on
two-dimensional surfaces and limit the access of non-cooperating bacteria to the
exchanged nutrients … p. 3
Enemy’s sex pheromone helps flies protect offspring
Female Drosophila flies avoid oviposition sites that smell of parasitic wasps. This
behavior increases the survival rate of their larvae. Researchers identified the
olfactory neuron in Drosophila which senses the fly’s enemies as well as the wasp
odors which trigger the avoidance behavior ... p. 4
The dandelion uses latex to protect its roots
Latex plays a crucial role in a plant’s defense against root feeders:
A single chemical compound in the latex sap of the dandelion deters
cockchafer larvae … p. 5
PULS/CE 27
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Newsletter May 2016 | Editorial
Internationality catches on!
The head of the new Max Planck Part-
Dear Readers!
ner Group at the National Institute of
Plant Genome Research (NIPGR),
Jyothilakshmi Vadassery (middle), and
the Jena delegation during the Kickoff Workshop in Delhi in December
2015. Photo: NIPGR,Delhi, India
Marcia González Teuber and Wilhelm
Boland celebrate the initial ceremony
of the first Max Planck Partner Group
in Chile. Photo: Universidad de La
Serena, Chile
In the editorial of our last issue I wrote about
the importance of internationality in science,
especially in light of the many global crises the
world is currently facing. I would like to develop
these thoughts on the internationality of research
projects a little further, this time because of very
good news: Within the last few months our institute received confirmation that five new Max
Planck Partner Groups will be funded: in Chile
(Marcia González Teuber), Peru (Alfredo Ibáñez),
India (Jyothilakshmi Vadassery and Radhika
Venkatesan) and South Africa (Almuth Hammerbacher).
It is the explicit mission of the Max Planck
Society to promote international collaboration
in research. Cutting-edge research cannot be
contained within; the exchange of knowledge
has the potential to promote new and innovative discoveries. An important tool to drive such
internationalization is the International Max
Planck Research School (IMPRS). Our IMPRS,
“The Exploration of Ecological Interactions with
Molecular and Chemical Techniques,“ launched
in 2004, has led to 150 young scientists receiving their doctorate; about half come from
abroad. Although many of these successful young
scientists return to their home countries with their
state-of-the-art scientific know-how, they also
remain important partners of their Max Planck
institutes. For these young international experts,
the Max Planck Society has developed another
instrument: Max Planck partner groups.
Five young scientists have now been given the
chance to establish their own partner group back
home. Often the scientific projects of these groups
focus on organisms native to the home countries
of their project leaders: Marcia González Teuber
from the University of La Serena, Chile, examines the native Chilean plant Prosopis chilensis,
a tree that owes its ability to resist drought to
endophytic fungi. Radhika Venkatesan studies
the chemical ecology of the biodiverse flora and
fauna in the Western Ghats, a mountain range on
the western coast of the Indian peninsula. Partner groups receive funding for a maximum of five
years. Each partner group celebrates its official
start with an international workshop and invites
colleagues from the partnering Max Planck institute. The name “Max Planck” opens many doors
and practically guarantees a positive reception in
the respective countries, including representatives of the government.
We wish the new groups all the best and hope
their collaborations prove successful, further expanding international knowledge networks.
Angela Overmeyer
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PULS/CE 273
Research Highlight | Newsletter May 2016
Cooperating bacteria isolate cheaters
Bacteria that engage in the cooperative exchange
of nutrients can save a significant amount of energy. This division of labor of certain metabolic processes has a positive effect on bacterial growth.
In a new study, researchers ask how such cooperative interactions can persist if non-cooperating
bacteria consume amino acids without providing
nutrients in return. For cooperating cells, the evolutionary disadvantage that results could lead to
a collapse of the cross-feeding interaction.
Scientists from the research group Experimental
Ecology and Evolution headed by Dr. Christian
Kost and colleagues from Jena University have
now studied this possibility experimentally and
monitored co-cultures of cooperating and noncooperating bacteria. To do this, they genetically engineered “cooperators” of two bacterial
species that released increased amounts of certain amino acids into their environment. Surprisingly, non-cooperators grew better than cooperators in a well-mixed liquid medium, because under
these conditions, they had unrestricted access to
the amino acids in the medium. Their growth,
however, was considerably reduced when bacteria were placed on a two-dimensional surface. A
detailed analysis revealed that non-cooperating
bacteria could exist only at the very fringe of colonies that were made up of cooperating bacteria .
For their study, the scientists combined different methods and techniques,. The basis of the
approach was a new research discipline called
“synthetic ecology”. In this approach, mutations are introduced into bacterial genomes. The
resulting bacterial mutants are then co-cultured
and their ecological interactions analyzed. At the
same time, scientists developed computer models
to simulate these interactions. Finally, chemical
analyses using mass spectrometric imaging are
instrumental for visualizing the bacterial metabolites. The results suggest that two cooperating
bacterial strains and a two-dimensional surface
are sufficient to stabilize complex cooperative
interactions between bacteria. This effect may
also play an important role in natural bacterial
communities, as bacteria occur predominantly on
so-called biofilms – these are surface-attached
slime layers that consist of many bacterial
species. Known examples include bacteria that
cause dental plaque or bacterial communities
that are used in wastewater treatment plants.
Moreover, biofilms are highly relevant for medical research: Not only are they crucial for treating
many infectious diseases by protecting bacterial pathogens from antibiotics or the patients’
immune responses, but biofilms are also highly
problematic when colonizing and spreading on
the surfaces of medical implants. Understanding the factors and mechanisms that promote or
inhibit bacterial growth could thus provide
important clues on how to fight harmful bacteria
or to better use beneficial ones. [CK/AO]
Above: The experiment (bacterial
colony, left) corresponds to computer
simulations (right): Opportunistic
bacteria (green) are only found on
the fringe of cooperating bacterial
colonies (red). Image: Samay Pande,
MPI-CE, Stefan Lang, Bioinformatics,
FSU Jena
Below left: Experimental ecology:
Christian Kost explains the experimental design and the analysis of results
of experiments with bacteria which
exchange nutrients in coculture.
Photo: Anna Schroll
Original Publication:
Pande, S., Kaftan, F., Lang, S., Svatoš,
A., Germerodt, S., Kost, C. (2015).
Privatization of cooperative benefits
stabilizes mutualistic cross-feeding
interactions in spatially structured
environments. The ISME Journal. doi:
10.1038/ismej.2015.212
PULS/CE 27
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Newsletter May 2016 | Research Highlight
Their enemy’s sex pheromone alerts female flies
Scientists from the Department of Evolutionary
Neuroethology led by Bill Hansson and Markus
Knaden found that the vinegar fly Drosophila
melanogaster houses an olfactory neuron which
is entirely dedicated to detecting the sex pheromone of parasitic wasps.
A parasitic wasp (Leptopilina boulardi)
lays its eggs into larvae of the vinegar
fly Drosophila melanogaster.
Photo: Markus Knaden, MPI-CE
A combination of gas-chromatographic and electrophysiological analyses as well as behavioral
assays with flies and larvae led to the results.
By applying these methods, the scientists could
identify both the wasp odors and the olfactory
receptors in Drosophila which detected the odors.
Last but not least, they were able to demonstrate
that the perception of these odors influenced the
flies’ behavior: Adult flies as well as their larvae
actively avoided sites in which the the smell of
parasitic wasps was strong.
Below right: Shimaa Ebrahim, the first
author of the study, comes from Egypt
and is ad doctoral student at the MPI
since 2013. She studies the odorguided behavior of vinegar flies.
Photo: Anna Schroll
Original Publication:
Ebrahim, S. A. M., Dweck, H. K. M.,
Stökl, J., Hofferberth, J. E., Trona,
F., Weniger, K., Rybak, J., Seki, Y.,
Three components of the wasps’ odor activate a
single olfactory neuron on the antennae of adult
Drosophila flies. Chemical analysis revealed
that these three substances are actinidine,
nepatalctol, and iridomyrmecin. Interestingly,
iridomyrmecin is the sex pheromone of the female
Leptopilina wasp. Although adult flies have two
olfactory receptors and can detect all three substances in the wasps’ odor, Drosophila larvae lack
one of the two receptors; they smell only the sex
pheromone iridomyrmecin.
Stensmyr, M. C., Sachse, S., Hansson,
B. S., Knaden, M. (2015). Drosophila
avoids parasitoids by sensing their
semiochemicals via a dedicated
olfactory circuit. PLOS Biology 13(12):
e1002318.
The results show again how highly specific individual olfactory receptors in Drosophila can be.
Odors that are of particular importance for the fly
are not detected and processed by the general
system; each of these odors has its own channel.
Separate channels prevent environmental odors
from interfering with odors relating to dangerous
bacteria (geosmin) or the best oviposition sites
(limonene).
The strength of this study is that it combines several lines of evidence − chemical and physiological analyses as well as behavioral experiments
with flies and larvae. The researchers suggest
that vinegar flies have learned to use the odor of
parasites for their own advantage in the course
of evolution. This strategy, which has evolved as
a means of self-protection, is especially astonishing because the avoidance of the wasps’ odor is
innate, as shown in experiments using flies that
had never been close to parasitic wasps and did
not know the scent of Leptopilina. Four other
Drosophila species demonstrated the same
avoidance behavior when they encountered the
odor of the wasps. Any counter-adaptation by
the wasps is difficult, because the release of this
pheromone is indispensable for reproduction.
That vinegar flies avoid their enemies by using
their sex pheromone as an olfactory cue is a very
clever move in the “game” of co-evolution. [AO]
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PULS/CE 27
Research Highlight | Newsletter May 2016
Latex protects
dandelion roots
The common cockchafer (Melolontha melolontha) spends the first three years of its life cycle
underground as a grub feeding on the roots of
different plants. Some of its favorite foods are
the roots of the dandelion (Taraxacum officinale). Like many other plants, dandelions produce
secondary metabolites to protect themselves
against herbivores. The most important dandelion
metabolites are bitter substances which are
found in the plant’s milky sap, called “latex.”
Scientists from the Department of Biochemistry
and their colleagues from the University of Bern
have now taken a close look at dandelion latex. The
scientists found the highest concentrations of the
bitter latex in the roots of dandelions. Dandelions
need to protect their roots because, as the main
storage organs for nutrients, these fuel growth
early in the spring. The scientists first tested
whether latex compounds produced by dandelion
roots were negatively associated with the development of cockchafer larvae. They also wanted
to know if these compounds had a positive
effect on the fitness and reproductive success of
dandelions under attack by Melolontha melolontha. An analysis of the components of dandelion
latex revealed that a single substance negatively
influenced the growth of cockchafer larvae: the
sesquiterpene lactone, taraxinic acid beta-Dglucopyranosyl ester (TA-G). When the purified
substance was added e in ecologically relevant
amounts to their artificial diet, grubs fed considerably less. The researchers successfully identified the enzyme and the gene responsible for the
formation of a precursor of TA-G biosynthesis.
The roots of engineered plants with low levels of
TA-G were attacked by cockchafer larvae more
often than were the roots of plants with high
levels of the compound. The chemical composition of latex varies among lines of natural dandelions. A common garden experiment with different lines revealed that plants which produce
high amounts of TA-G maintained their high vegetative and reproductive fitness when they were
attacked by cockchafer larvae. That a single compound is responsible for the dandelion’s effective defense against cockchafer larvae surprised
the scientists. The variety of substances in the
latex of dandelions made it seem unlikely that one
chemical played such a crucial role in protecting
the plant from the study insects.
Above: The dandelion uses latex to
protect its roots against insect feeding.
Grafic: Kimberly Falk, Moves Like Nature
Meret Huber studies latex metabolites
in dandelion and their role in root herbivore defense. Photo: Anna Schroll
Original Publication:
Huber, M., Epping, J., Schulze Grono-
The scientists are now planning further experiments to study the co-evolution of dandelions and
their root herbivores in order of find out whether
the presence of root-feeding insects has shaped
the plant’s defensive chemistry in the course of
evolution and whether the cockchafers show
adaptations to dandelion defenses. [AO]
ver, C., Fricke, J., Aziz, Z., Brillatz, T.,
Swyers, M., Köllner, T. G., Vogel, H.,
Hammerbacher, A., Triebwasser-Freese, D., Robert, C. A. M., Verhoeven,
K., Preite, V. Gershenzon, J., Erb, M.
(2016). A latex metabolite benefits
plant fitness under root herbivore
attack. PLOS Biology 14(1): e1002332.
PULS/CE 27
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Newsletter May 2016 | News
The odor of stones
What happens when algae are fed with
a single silicate-loaded granule?
The tiny single-celled organisms move
back and forth to approach the silicate
source in the center of the screen
and virtually “gobble” it up. The algae
are able to cover a distance of two
micrometers per second. From a video
by Karen Grace Bondoc, Institute for Inorganic and Analytical Chemistry, FSU
Diatoms are unicellular algae that are native in
many waters. They are a major component of
marine phytoplankton and the food base for a
large variety of marine organisms. In addition,
they produce about one-fifth of the oxygen in the
atmosphere and are therefore a key factor for our
global climate. However, these algae, which measure only a few micrometers, have yet another
amazing ability: they can “smell” stones. To be
more precise, these algae are able to locate dissolved silicate. A recent study by Georg Pohnert,
Chair of Instrumental Analytics at Friedrich Schiller University and head of the new Max Planck
Fellow Group, and his research team demonstrate
that not only are diatoms able to trace silicate
minerals in the water, but they can even move
actively to areas where the concentration of
silicates is especially high. The scientists showed
that the diatoms were attracted solely by the
odor of the silicate. If the researchers replaced
the silicate mineral with structurally similar salts
containing germanium, which is toxic to the algae, the algae moved away.
The Jena chemists see potential for the long-term
practical application of their findings: knowledge
of the processes that make algae colonize one
particular area or avoid others could be used
to selectively design surfaces and materials in
such a way that they remain free of algae. Such
materials could be used for the hulls of ships or
for water pipes, both of which are often damaged
by algal colonization. [Ute Schönfelder, FSU / AO]
Original Publication:
Bondoc, K. G., Heuschele, J., Gillard, J., Vyverman, W.,
Pohnert, G. (2016). Selective silica-directed motility in
diatoms. Nature Communications 7:10540
Terpene synthase gene mediates flea beetles’ mass attack
Two flea beetles (Phyllotreta striolata)
on a Brassica rapa leaf showing the
typical feeding pattern. Male beetles
produce a so-called aggregation
pheromone (here the sesquiterpene
(6R,7S)-Himachala-9,11-diene) to
attract conspecifics. This causes a
mass attack on the host plants.
Photo: Anna Schroll
Scientists from the Research Group Sequestration and Detoxification in Insects and the Department of Biochemistry identified a new family of
terpene synthase genes in insects. Terpenes are
metabolites which play an important role in the
chemical communication of insects. Flea beetles,
for instance, produce a chemical signal, the sesquiterpene (6R,7S)-himachala-9,11-diene, to lead
hungry conspecifics to their host plants. This
signal causes these pest insects to mass-attack
cabbage fields in North America and Asia. Until
now, the enzymes involved in the biosynthesis of
these important signal molecules were unknown.
In their new study, the researchers identified
an enzyme which catalyzes the biosynthesis of
(6R,7S)-himachala-9,11-diene, the aggregation
pheromone produced by male Phyllotreta striolata
flea beetles. Fundamental insights into how these
pest insects produce attractants to call in their
conspecifics to a mass attack could provide valuable clues how to better control them. [AO/FB]
Original Publication:
Beran, F., Rahfeld, P., Luck, K., Nagel, R., Vogel, H.,
Wielsch, N., Irmisch, S., Ramasamy, S., Gershenzon, J.,
Heckel, D. G., Köllner, T. G. (2016). Novel family of terpene
synthases evolved from trans-isoprenyl diphosphate synthases in a flea beetle. PNAS, 113(11), 2922-2927.
PULS/CE 27
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News | Newsletter May 2016
How stick insects handle indigestive food
with multifunctional cellulases
Plant cell walls are composed of complex polymers that require multiple enzymes to be fully
broken down; for example, cellulase is needed to
digest cellulose and xylanase is needed to digest
xylan. For decades, scientists thought only microbes could produce cellulase, until cellulase genes
were found in wood-feeding insects.
Now, researchers from the Department of Entomology have overturned another theory. The
scientists discovered that stick insects (Phasmatodea) produce cellulases that can handle several
types of cell wall polymers. The ability to break
down different polymers with the same enzymes
means the Phasmatodea gut is unusually effici-
ent. Helped by enzymes such as cellobiases and
xylobiases, the guts of these insects can fully
degrade nearly all the plant cell wall into its component sugars, using the sugars for nutrition as
well as to gain access to the easily digested cytoplasm within the cells. This means they can derive more nutrition from the same leafy diet than
other herbivores can. Theoretically, they could
even digest wood. [MS/AO]
A young Australian stick insect
(Extatosoma tiaratum) hangs upsidedown on a houseplant at the Max
Original Publication:
Planck Institute for Chemical Ecology.
Shelomi, M., Heckel, D. G., and Pauchet, Y. (2016). Ances-
Photo: Matan Shelomi, MPI-CE
tral Gene Duplication Enabled the Evolution of Multifunctional Cellulases in Stick Insects (Phasmatodea). Insect
Biochemistry and Molecular Biology 71, 1-11.
Stefan Pentzold receives a Marie Skłodowska-Curie Fellowship
Stefan Pentzold, a postdoc in the research group
Chemical Defense of Leaf Beetles (headed by
Antje Burse) was awarded a Marie SkłodowskaCurie individual fellowship and will receive
funding from the EU within the framework of the
Horizon 2020 program for the next two years.
His project is called „ChemoSense - Elucidating
the Mechanisms of Insect’s Chemical Taste to
Understand Specific Host-Plant Selection.“
He will study poplar leaf beetles (Chrysomela populi), especially their taste receptors, and
poplars, using transcriptomic sequencing, RNAi,
heterologous expression, LC-MS, and other analytical techniques to find out how and why these
herbivorous insects select their host plants. [AO]
Stefan Pentzold. Photo: private
Feodor Lynen Postdoctoral Fellowship for Hassan Salem
Hassan Salem from the Max Planck Research
Group Insect Symbiosis received a prestigious
Feodor Lynen Postdoctoral Fellowship from the
Alexander von Humboldt Foundation. The fellowship will provide funding for at least two years
to work in Nicole Gerardo‘s lab at Emory University in Atlanta, Georgia, USA. The research will
focus on genomic and metabolic determinants of
parasite specialization in fungus-farming ants.
[AO]
Hassan Salem. Photo: private
PULS/CE 27
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Newsletter May 2016 | News & Events
Scholarship prize of the Xinjiang Uyghur
Autonomous Region for Ayufu Yilamujiang
The Department of Education of the Xinjiang
Uyghur Autonomous Region, China, awarded
Ayufu Yilamujiang, PhD student in the project
group Plant Defense Physiology of the Department of Bioorganic Chemistry, a scholarship prize
for students studying abroad. He was selected
for his outstanding achievements during his study
in Germany, which began in 2008 and for his
research at the Max Planck Institute for Chemical
Ecology. [AO]
Ayufu Yilamujiang (left) at the award
ceremony. Photo: private
Upcoming Events:
Stefan H. E. Kaufmann. Photo: Max
Planck Institute for Infection Biology
Ebola, AIDS, tuberculosis, influenza: these threatening diseases not only terrify mankind, they also
have a major impact on human societies. At the same time, our body provides a the habitat for the
diverse microbiome, which is the entity made up of all microorganisms living with us in symbiosis and on which we depend. In fact, the microbial cells in our body outnumber our own cells by a
ratio of approximately 1000 to one. Renowned scientist Prof. Dr. Dr. h.c. Stefan H. E. Kaufmann,
director at the Max Planck Institute for Infection Biology in Berlin, will discuss what can be done to
contain epidemics and ask how our microbiome influences non-transmissible diseases. He will give
a public lecture on the topic “Man and microbe: enemy and friend“ („Mensch und Mikrobe:
Feind und Freund“) in the Beutenberg Campus lecture series “Noble Gespräche“ on Thursday,
May 12, 2016, at 5:00 p.m., in the lecture hall of the Abbe Center on Beutenberg, Hans-KnöllStraße 1, 07745 Jena. Admission is free.
http://www.beutenberg.de/de/noble_gespraeche.html
The City of Jena owes much of its current status as an important location of science and high technology to one person whose name is closely associated with Jena: Carl Zeiss, the founder of the
company for precision engineering and optics known worldwide as ZEISS. His close collaboration with
scientists at the University of Jena, including physician Ernst Abbe and botanist Matthias Schleiden,
facilitated the ongoing advancement of microscopes, which then enabled pioneering microbiologist
Robert Koch to make his ground-breaking discoveries. Without ZEISS microscopes, Koch could not have
identified the bacterium which causes tuberculosis or the causative agents of other diseases. The Max
Planck Institute for Chemical Ecology also uses modern high-performance microscopes for research
purposes. Carl Zeiss Day is a festival for the whole family whcih will be celebrated on the 200th
birthday of Carl Zeiss. On Sonday, September 11, 2016, from 10:00 a.m. until 5:00 p.m., our institute will show exhibits relating to the topic “Microcosm Plants and Insects – Fascinating details
of vinegar flies, tobacco plants and other model organisms” together with many other exhibitors
in the Jena city center. .
www.zeiss.de/carlzeiss200
www.ice.mpg.de
Impressum: PULS/CE is published semi-annually and can be downloaded free of charge on the homepage of the
MPI for Chemical Ecology and is distributed electronically as PDF to subscribers. A print version will be sent on request.
Editor: MPI-CE, Jena • Managing Director: Prof. Dr. David G. Heckel (viSdP). Editorial Staff: Angela Overmeyer, M.A.,
Information and Communication • Emily Wheeler, Editing
ISSN: 2191-7507 (Print), 2191-7639 (Online)