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Schönau am Königssee, Germany

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Schönau am Königssee, Germany
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Vodisch M.,Leibniz Institute for Natural Product Research and Infection Biology | Scherlach K.,Leibniz Institute for Natural Product Research and Infection Biology | Winkler R.,Leibniz Institute for Natural Product Research and Infection Biology | Hertweck C.,Leibniz Institute for Natural Product Research and Infection Biology | And 6 more authors.
Journal of Proteome Research | Year: 2011

The mold Aspergillus fumigatus is the most important airborne fungal pathogen. Adaptation to hypoxia represents an important virulence attribute for A. fumigatus. Therefore, we aimed at obtaining a comprehensive overview about this process on the proteome level. To ensure highly reproducible growth conditions, an oxygen-controlled, glucose-limited chemostat cultivation was established. Two-dimensional gel electrophoresis analysis of mycelial and mitochondrial proteins as well as two-dimensional Blue Native/SDS-gel separation of mitochondrial membrane proteins led to the identification of 117 proteins with an altered abundance under hypoxic in comparison to normoxic conditions. Hypoxia induced an increased activity of glycolysis, the TCA-cycle, respiration, and amino acid metabolism. Consistently, the cellular contents in heme, iron, copper, and zinc increased. Furthermore, hypoxia induced biosynthesis of the secondary metabolite pseurotin A as demonstrated at proteomic, transcriptional, and metabolite levels. The observed and so far not reported stimulation of the biosynthesis of a secondary metabolite by oxygen depletion may also affect the survival of A. fumigatus in hypoxic niches of the human host. Among the proteins so far not implicated in hypoxia adaptation, an NO-detoxifying flavohemoprotein was one of the most highly up-regulated proteins which indicates a link between hypoxia and the generation of nitrosative stress in A. fumigatus. © 2011 American Chemical Society.


Drescher S.,Institute of Pharmacy | Graf G.,Institute of Chemistry | Hause G.,Biocenter | Dobner B.,Institute of Pharmacy | Meister A.,Institute of Chemistry
Biophysical Chemistry | Year: 2010

Herein, we report the synthesis of two novel, amino-functionalized single-chain bolalipids and, based on those, a general synthetic approach for the insertion of various carboxylic acids into the bolalipid headgroups, e.g. α-lipoic acid for one-dimensional fixation of gold nanoparticles, sorbic acid for polymerization experiments, or lysine for the use in gene delivery systems. The temperature- and pH-dependent self-assembly of amino-functionalized bolalipids into nanofibers and micelles was investigated by differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Rheological measurements were used to describe the macroscopic behavior of the formed temperature switchable hydrogels that can be fine-tuned for drug delivery applications. We showed that the viscoelastic properties of the hydrogel strongly depend on ionic interactions between bolalipid headgroups as well as on the ability to form hydrogen bonds. © 2010 Elsevier B.V.


Nanda I.,Institute for Human Genetics | Schories S.,Biocenter | Tripathi N.,Max Planck Institute for Developmental Biology | Dreyer C.,Max Planck Institute for Developmental Biology | And 4 more authors.
Chromosoma | Year: 2014

Sex chromosomes differ from autosomes by dissimilar gene content and, at a more advanced stage of their evolution, also in structure and size. This is driven by the divergence of the Y or W from their counterparts, X and Z, due to reduced recombination and the resulting degeneration as well as the accumulation of sex-specific and sexually antagonistic genes. A paradigmatic example for Y-chromosome evolution is found in guppies. In these fishes, conflicting data exist for a morphological and molecular differentiation of sex chromosomes. Using molecular probes and the previously established linkage map, we performed a cytogenetic analysis of sex chromosomes. We show that the Y chromosome has a very large pseudoautosomal region, which is followed by a heterochromatin block (HCY) separating the subtelomeric male-specific region from the rest of the chromosome. Interestingly, the size of the HCY is highly variable between individuals from different population. The largest HCY was found in one population of Poecilia wingei, making the Y almost double the size of the X and the largest chromosome of the complement. Comparative analysis revealed that the Y chromosomes of different guppy species are homologous and share the same structure and organization. The observed size differences are explained by an expansion of the HCY, which is due to increased amounts of repetitive DNA. In one population, we observed also a polymorphism of the X chromosome. We suggest that sex chromosome-linked color patterns and other sexually selected genes are important for maintaining the observed structural polymorphism of sex chromosomes. © 2014 Springer-Verlag.


News Article | December 26, 2016
Site: www.techtimes.com

The uneven distribution and biodiversity on Earth had been a big puzzle. Now, a new study says biodiversity distribution is driven more by temperature differences as seen in the least diversity of plants and animals in arctic regions in contrast to the abundance in tropical latitudes where new organisms are discovered constantly. The reason for tropics housing more species than higher latitudes has been intriguing most ecologists, according to Professor Ingolf Steffan-Dewenter from the University of Würzburg's Biocenter. "Already about ten years ago, the publishers of Science declared this to be one of the 25 most important questions of science to be answered yet," he said. The number of species living in an area is governed by the primary productivity of a habitat, which implies that a larger cake can "sustain more species than a smaller one," explains Marcell Peters, a Würzburg ecologist. The study has been published in Nature. The hypothesis is that both evolution and speciation are driven by temperature with warmer climate attracting more species than colder regions. These were examined by studies on selected species such as birds, bees, ants, or ferns in different regions as in North America, Europe, or the mountains of Alps. Meanwhile, measuring of biodiversity by using remote sensing tools has been effective in the last 30 years in addition to many field studies. According to a team of international researchers, opportunities in remote sensing hold enormous potential in assisting future biodiversity research. This is because climate changes are best marked by changes in biodiversity as it captures the contemporary situation within ecosystems. "To do this we need reliable data across large areas and close periods of time," said UFZ Landscape Ecologist PD Angela Lausch. An example is the distribution of plant species being studied with satellite images to determine growth habit, leaf geometry, flower color on a bigger scale for area, and time. Given the upcoming launch of hyperspectral satellite EnMAP (Environmental Mapping and Analysis Program) in 2018 to supply image data with high resolution, the scope of sensing is going to expand and it will measure more biochemical parameters including nitrogen, phosphate, or water in tissues of leaves. The reason of tropics having the greatest biodiversity on Earth in terms of variety and number with a diminishing trend toward the poles has been probed by scientists. It was found that this latitudinal diversity gradient is indeed a good tool in taking measures for halting biodiversity loss and in protecting areas with a variety of species. The study led by David Jablonski, from the University of Chicago's Geophysical Sciences department and colleagues at the University of California reconciled the conflicting ideas in a paper published in the The American Naturalist. One idea states that local factors are shaping the biodiversity of a region, while in a few cases, lineages from outside are entering adjoining geographical to enhance the biodiversity of a region. "The gradient involves mutually reinforcing causes — 'perfect storms' rather than a single mechanism," Jablonski explained. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


Mischnik M.,Institute of Physics | Hubertus K.,Institute for Clinical Biochemistry and Pathobiochemistry | Geiger J.,Institute for Clinical Biochemistry and Pathobiochemistry | Dandekar T.,Biocenter | And 3 more authors.
Molecular BioSystems | Year: 2013

Prostaglandins are the key-players in diminishing platelet function. They exert their effects via a variety of surface receptors that are linked to the cAMP/PKA-signalling cascade. However, less is known about the quantitative impact of the individual receptors on the underlying pathway. We present here a comprehensive ordinary differential equation-based model of the platelet cAMP pathway, including the four prostaglandin receptors IP, DP1, EP3 and EP4, the ADP receptor P2Y12, a detailed PKA-module as well as downstream-targets. Parameter estimation along with a comprehensive combination of time-course and dose-response measurements revealed the individual quantitative role of each receptor in elevating or decreasing pathway activity. A comparison of the two inhibiting receptors EP3 and P2Y12 exhibited a greater signalling strength of the EP3 receptor with implications for antithrombotic treatment. Furthermore, analysis of different model topologies revealed a direct influence of PKA on adenylate cyclase, reducing its maximum catalytic speed. Finally, we show here for the first time the dynamic behaviour of VASP-phosphorylation, which is commonly used as a marker for platelet-inhibition. We validate our model by comparing it to further experimental data. © 2013 The Royal Society of Chemistry.


News Article | December 22, 2016
Site: www.eurekalert.org

The diversity of plants and animals in Earth's arctic regions is moderate. Tropical latitudes in contrast are teeming with different species where new organisms are being discovered all the time. What is the cause of this uneven distribution? Why are the tropics home to more species than higher latitudes? "This question has intrigued ecologists for some time," says Professor Ingolf Steffan-Dewenter from the University of Würzburg's Biocenter. "Already about ten years ago, the publishers of Science declared this to be one of the 25 most important questions of science to be answered yet." To date, this core question has been subject to controversy. One hypothesis, for instance, is that the primary productivity of a habitat is ultimately decisive for the number of species living there. Simply put: "A larger cake can sustain more species than a small one," explains Würzburg ecologist Dr. Marcell Peters. Another hypothesis assumes that the rate of evolution and speciation depend on temperature. According to this assumption, more species thrive in a warmer climate than in a cold one. So far, these hypotheses have been examined usually by focusing on selected groups of species: For example, the studies observed only birds, bees, ants or ferns and analysed their diversity in different regions of the world, e.g. in North America, Europe or along elevational gradients in the Alps. "Some studies supported one hypothesis, whereas others backed another assumption," Peters says and states that it is still a long way from establishing a "general rule" which ecologists are aiming for. In the journal "Nature Communications" Peters and the team of the Research Unit "FOR1246" funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) now present a new study which is unique so far and is the synthesis of four years of working: "On Mount Kilimanjaro, one of Earth's largest climatic gradients, we observed so many animal and plant groups in parallel as never before," the researcher says. Overall, the team examined eight groups of plants and 17 groups of animals, from bees to bats. 38 scientists from Germany, Tanzania and other countries participated in the large-scale study; they were supported by around 50 local drivers, carriers and other assistants. "We had to climb in mountainous areas for several days to reach the highest study sites," Peters says. The area of study stretched from the savannahs at the foot of the mountain to the habitats at an altitude of 4,550 metres that barely sustain plants. The data across all groups were collected over the same areas and in the same period of time, respectively. "This approach allowed us to not only analyse the biodiversity of each individual group, but also that of whole communities." The study revealed that biodiversity in communities is mainly determined by temperature. The warmer it is, the greater the diversity. "The more groups of animals and plants you investigate in parallel, the greater the significance of temperature for explaining biodiversity, whereas the importance of all other variables decreases accordingly." The scientists believe that this is strong evidence supporting the assumption that temperature is actually more decisive for distribution patterns of overall biodiversity than productivity or size of habitats.


Naseem M.,Biocenter | Philippi N.,Biocenter | Philippi N.,Max Planck Institute for Biology of Ageing | Hussain A.,University of Punjab | And 4 more authors.
Plant Cell | Year: 2012

Phytohormones signal and combine to maintain the physiological equilibrium in the plant. Pathogens enhance host susceptibility by modulating the hormonal balance of the plant cell. Unlike other plant hormones, the detailed role of cytokinin in plant immunity remains to be fully elucidated. Here, extensive data mining, including of pathogenicity factors, host regulatory proteins, enzymes of hormone biosynthesis, and signaling components, established an integrated signaling network of 105 nodes and 163 edges. Dynamic modeling and system analysis identified multiple cytokinin-mediated regulatory interactions in plant disease networks. This includes specific synergism between cytokinin and salicylic acid pathways and previously undiscovered aspects of antagonism between cytokinin and auxin in plant immunity. Predicted interactions and hormonal effects on plant immunity are confirmed in subsequent experiments with Pseudomonas syringae pv tomato DC3000 and Arabidopsis thaliana. Our dynamic simulation is instrumental in predicting system effects of individual components in complex hormone disease networks and synergism or antagonism between pathways. © 2012 American Society of Plant Biologists. All rights reserved.


News Article | December 5, 2016
Site: www.eurekalert.org

Flatfish are some of the most unusual vertebrate animals on our planet. They start out their life fully symmetrical, like any other fish, but undergo a spectacular metamorphosis where the symmetric larva is transformed into an asymmetric juvenile whose eyes end up on one side of the head. As they relocate from open water to live and feed on the seabed, a second change occurs: The flounder's downward-facing side loses its skin pigment. These transformations require the flatfish do undergo radical change, both in physiology and behavior. The puzzle of how these changes could occur in the course of evolution has been intriguing scientists for a long time. Even Darwin was at a loss to explain the "remarkable peculiarity" of flatfish anatomy. An international team of researchers has now unlocked the decisive mechanisms driving the metamorphosis. The team was led by biochemist Manfred Schartl, Head of the Department for Physiological Chemistry at the University of Würzburg's Biocenter, with his former Würzburg student and co-worker Songlin Chen from the Yellow Sea Fisheries Research Institute in China. The scientists have published their findings in the current issue of the journal Nature Genetics. "We recently sequenced the genome of both the Japanese flounder (Paralichthys olivaceus) and its distant relative, the tongue sole (Cynoglossus semilaevis)," Manfred Schartl explains. The comparison of the two genomes delivered the clue about the genetic bases of the radical physiological changes. Focusing on the genes that were active during the metamorphosis, the scientists identified a key developmental trigger: retinoic acid. "Retinoic acid is responsible for the changes in skin pigments in flounders and interacts with a thyroid hormone that causes both eyes to migrate to one half of the body," Schartl sums up the central results of their work. Light also plays a central role in this process as the researchers were surprised to find out during their work. They discovered that the same pigments that capture light in the eye are expressed in the skin of the flounder larvae. "They sense differences in brightness to adjust the concentration of retinoic acid," Schartl says. This in turn affects the thyroid hormone and promotes asymmetry generation. Scientists of various research institutes in China participated in the study. They received financial support among others from the Chinese Ministry of Agriculture. In addition to scientific reasons, this has an economic background: Flounders are highly priced food fish and accordingly expensive. To meet the increasing demand, China operates huge fish farms that produce more than half of the world's farmed fish. However, failures in metamorphosis are a frequent problem in flounder aquaculture accounting for many millions of dollars of losses in production. Understanding how these unique creatures develop not only solves a long-standing evolutionary puzzle, it also serves the fishing industry and helps feed a continuously growing population.


News Article | December 5, 2016
Site: phys.org

As they relocate from open water to live and feed on the seabed, a second change occurs: The flounder's downward-facing side loses its skin pigment. These transformations require the flatfish do undergo radical change, both in physiology and behavior. The puzzle of how these changes could occur in the course of evolution has been intriguing scientists for a long time. Even Darwin was at a loss to explain the "remarkable peculiarity" of flatfish anatomy. An international team of researchers has now unlocked the decisive mechanisms driving the metamorphosis. The team was led by biochemist Manfred Schartl, Head of the Department for Physiological Chemistry at the University of Würzburg's Biocenter, with his former Würzburg student and co-worker Songlin Chen from the Yellow Sea Fisheries Research Institute in China. The scientists have published their findings in the current issue of the journal Nature Genetics. "We recently sequenced the genome of both the Japanese flounder (Paralichthys olivaceus) and its distant relative, the tongue sole (Cynoglossus semilaevis)," Manfred Schartl explains. The comparison of the two genomes delivered the clue about the genetic bases of the radical physiological changes. Focusing on the genes that were active during the metamorphosis, the scientists identified a key developmental trigger: retinoic acid. "Retinoic acid is responsible for the changes in skin pigments in flounders and interacts with a thyroid hormone that causes both eyes to migrate to one half of the body," Schartl sums up the central results of their work. Light also plays a central role in this process as the researchers were surprised to find out during their work. They discovered that the same pigments that capture light in the eye are expressed in the skin of the flounder larvae. "They sense differences in brightness to adjust the concentration of retinoic acid," Schartl says. This in turn affects the thyroid hormone and promotes asymmetry generation. Scientists of various research institutes in China participated in the study. They received financial support among others from the Chinese Ministry of Agriculture. In addition to scientific reasons, this has an economic background: Flounders are highly priced food fish and accordingly expensive. To meet the increasing demand, China operates huge fish farms that produce more than half of the world's farmed fish. However, failures in metamorphosis are a frequent problem in flounder aquaculture accounting for many millions of dollars of losses in production. Understanding how these unique creatures develop not only solves a long-standing evolutionary puzzle, it also serves the fishing industry and helps feed a continuously growing population. More information: The genome and transcriptome of Japanese flounder provide insights into flatfish asymmetry, Nature Genetics, nature.com/articles/doi:10.1038/ng.3732


News Article | December 22, 2016
Site: phys.org

The diversity of plants and animals in Earth's arctic regions is moderate. Tropical latitudes, in contrast, are teeming with multiple specie, and new organisms are being discovered all the time. What is the cause of this uneven distribution? Why are the tropics home to more species than higher latitudes? "This question has intrigued ecologists for some time," says Professor Ingolf Steffan-Dewenter from the University of Würzburg's Biocenter. "About 10 years ago, the publishers of Science declared this to be one of the 25 most important questions of science yet to be answered." There are many hypotheses. One, for instance, is that the primary productivity of a habitat is ultimately decisive for the number of species living there. Simply put: "A larger cake can sustain more species than a small one," according to Würzburg ecologist Dr. Marcell Peters. Another hypothesis assumes that the rate of evolution and speciation depend on temperature. According to this assumption, more species thrive in a warmer climate than in a cold one. These hypotheses have usually been examined by focusing on selected groups of species. For example, the studies observed only birds, bees, ants or ferns and analysed their diversity in different regions of the world, e.g. in North America, Europe or along elevational gradients in the Alps. "Some studies supported one hypothesis, whereas others backed another assumption," Peters says, and states that it is still a long way from establishing a "general rule," which ecologists are aiming for. In the journal Nature Communications, Peters and the research unit "FOR1246" present a new study after four years of working: "On Mount Kilimanjaro, one of Earth's largest climatic gradients, we observed so many animal and plant groups in parallel as never before," the researcher says. Overall, the team examined eight groups of plants and 17 groups of animals, from bees to bats. Thirty-eight scientists from Germany, Tanzania and other countries participated in the large-scale study; they were supported by around 50 local drivers, carriers and other assistants. "We had to climb in mountainous areas for several days to reach the highest study sites," Peters says. The area of study stretched from the savannahs at the foot of the mountain to the habitats at an altitude of 4,550 metres that barely sustain plants. The data across all groups were collected over the same areas and in the same period of time, respectively. "This approach allowed us not only to analyse the biodiversity of each individual group, but also that of whole communities." The study revealed that biodiversity in communities is mainly determined by temperature. The warmer it is, the greater the diversity. "The more groups of animals and plants you investigate in parallel, the greater the significance of temperature for explaining biodiversity, whereas the importance of all other variables decreases accordingly." The scientists believe that this is strong evidence supporting the assumption that temperature is actually more decisive for distribution patterns of overall biodiversity than productivity or size of habitats. Explore further: Impact of climate change on microbial biodiversity depends on environmental quality

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