Yearbook 2011

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Progesterone controls the intracellular Ca2+ concentration and, thereby, the swimming behaviour of human sperm - this has been known for 25 years. However, the mechanism of action of the female sex hormone in sperm has remained mysterious and highly controversial. Researchers from the research center caesar in Bonn have now solved this long standing mystery: Progesterone directly opens sperm-specific CatSper (cation channel of sperm) Ca2+ channels located in the membrane of the sperm´s tail. more
In the middle of their development, the embryos of different species show maximal similarity – embryogenesis diverges more extensively prior and after that phase, known as the hourglass model. Also the expression patterns of the genes involved show greatest similarities between embryos during the phylotypic stage. The genes that conform most to the hourglass pattern are involved in key developmental processes. These results give an insight into the molecular basis of the hourglass pattern and indicate that natural selection acts to conserve patterns of gene expression during mid-embryogenesis. more
Light sheet microscopy has contributed substantially to the emerging field of real-time developmental biology. Advantages of new systems are low photo-toxicity and high-speed multiview acquisition, which make them a popular choice for studies of organ morphogenesis in model organisms. A variety of light sheet microscopes have emerged for the noninvasive imaging of specimens ranging from single molecules to cells, tissues, and entire embryos. This enables researchers to watch developmental events occur in real time in an entire embryo, and to understand how cells form tissues and organs. more
A wide variety of problems in science and technology is concerned with the study of biological and synthetic nanoparticles. Being less than one hundred nanometers in size, such objects often elude conventional techniques of detection and measurement. Nanofluidic resonators have recently enabled the direct weighing of single nanoparticles and the measurement of size distributions in complex liquid samples. Such measurements are important to help advance our understanding of many fundamental processes in biophysics, medicine, biology, biotechnolgy. more
Eukaryotic pre-mRNAs contain non-coding regions (introns) which need to be removed before the mRNA can be used for the synthesis of proteins. This so-called splicing process is catalysed in the cell's nucleus by the spliceosome, a highly complex and dynamic molecular machine. It is composed of numerous protein and RNA components and it is assembled anew on each intron to be removed from an RNA transcript. Using approaches from biochemistry, molecular biology, genetics and structural biology, we study the complex catalytic work cycle of the spliceosome to understand its structure and function. more
The Earth’s atmosphere is a complex system with a multitude of physical and chemical processes. To better understand this system a wide range of gases present at very low concentrations must be measured. This not only means the use of a range of measurement equipment. To track chemical changes in the atmosphere, long term, regular measurements on a global scale are needed. The Max Planck Institute for Chemistry has in cooperation with Lufthansa Airlines developed a unique measurement container which carries out measurements on a monthly basis as airfreight during long range flights. more
The exchange of nitrogen dioxide (NO2) between vegetation and the atmosphere was studied with six tree species under controlled laboratory conditions. Additionally, two tree species were investigated under field conditions. Uptake was found to be strongly correlated with plant stomatal aperture (conductance). Upon stomatal closure uptake was decreasing to zero. Uptake rates exhibited a linear dependency with the ambient NO2 concentration. The data contradict the existence of a compensation point for natural ecosystems and underline the role of vegetation as a sink for this trace gas. more
Humans act and interact in a social environment. Research in developmental psychology addresses the cognitive mechanisms that form the bedrock of the understanding of goal-directed actions. Recent findings indicate that early in life, actions such as grasping and pointing are already processed similarly as in adults on both the behavioural and the neurophysiological level. Research paradigms that can be applied with infants as well as with adults open up the possibility to explore social-cognitive development over a wide age range. more
The question of the origin of human self-consciousness has recently been rediscovered by Cognitive scientists and neuroscientists. New research suggests that especially internal motor-related prediction processes contribute to the automatic self-ascription of events as well as to the subjective experience of authorship and control of actions. Accordingly, central aspects of our sense of self can directly be located in our body and be characterized as a by-product of actions. more
German civil procedural law states that a judge freely forms his or her conviction on the truth of disputed factual statements. When assessing the facts of a case, a judge must hold a number of partial beliefs at the same time, some of which may be dependent on each other. So called Bayes Nets allow a graphic display of these partial beliefs and their (in)dependencies. The use of Bayes Nets forces coherence of the partial beliefs in the sense of subjective probability theory and allows testing how various assumptions influence the judge’s conviction. more
With nearly 1 million people dying per year, malaria is a global health problem. Artemisinin combination therapies are regarded as first-line drugs. However, their supply is limited, as artemisinin is currently solely extracted from plants. Its precursor dihydroartemisinic acid on the other hand can be obtained by a biotechnological process. A continuous flow chemistry setup was developed to produce artemisinin from this precursor in high yield just using oxygen and light. more
Interfacial properties influence the bulk phase behavior and often the bulk structure. For very small systems (nanoparticles, thin films) this is obvious. The relative amount of interfacial molecules is large. Yet, interfacial influences often are also important for macroscopically large systems because these typically originate from small nano size aggregates. In addition, the growth to macroscopic size always occurs at the interface. Local interfacial transport conditions affect the growth kinetics and thus also the structure and properties of the resulting macroscopic entity. more
Synthetic sugars offer great potential e.g. for the development of new treatments or vaccines. Thus chemists have been searching for new molecules offering the same biological activity that can be synthesized more easily. One important class of such mimetics are sugar polymers, a combination of polymer chains with natural sugars. In order to understand how such sugar polymers mimic the activity of natural sugars and how to more effectively synthesize such sugar polymers, a new class of monodisperse polymers is currently developed at the MPICI and tested for their properties. more
Robots acquire information from the environment, process it and then use it to autonomously perform tasks. A big challenge is to have robots and humans cooperate effectively in our every day’s life. To realize this vision the role of humans must be taken into account. Robot design and control must be conceived to meet the human needs and facilitate the interaction. Our research efforts are guided by these principles and aimed at realizing semi-autonomous robotic systems able to perform local tasks – supervised by a human – on their own in a so-called shared control scenario. more
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