Tutanchamuns Gebiss und Kieferrelation

Über Gebiss und Kieferrelation von Pharao Tutanchamun existieren kaum Berichte. Unsere kephalometrische Untersuchung ergab eine mandibuläre Retrognathie sowie eine milde maxilläre Prognathie.About pharaoh Tutankhamun‘s dentition only a few reports exist. Regarding the jaw relation, our cephalometric investigation revealed a mandibular retrognathism and a mild maxillary prognathism

"Wissenschaft fürs Wohnzimmer" – two years of interactive, scientific livestreams weekly on YouTube

Science communication is becoming increasingly important to connect academia and society, and to counteract fake news among climate change deniers. Online video platforms, such as YouTube, offer great potential for low-threshold communication of scientific knowledge to the general public. In April 2020 a diverse group of researchers from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research launched the YouTube channel "Wissenschaft fürs Wohnzimmer" (translated to "Sitting Room Science") to stream scientific talks about climate change and biodiversity every Thursday evening. Here we report on the numbers and diversity of content, viewers, and presenters from 2 years and 100 episodes of weekly livestreams. Presented topics encompass all areas of polar research, social issues related to climate change, and new technologies to deal with the changing world and climate ahead. We show that constant engagement by a group of co-hosts, and presenters from all topics, career stages, and genders enable a continuous growth of views and subscriptions, i.e. impact. After 783 days the channel gained 30,251 views and 828 subscribers and hosted well-known scientists while enabling especially early career researchers to improve their outreach and media skills. We show that interactive and science-related videos, both live and on-demand, within a pleasant atmosphere, can be produced voluntarily while maintaining high quality. We further discuss challenges and possible improvements for the future. Our experiences may help other researchers to conduct meaningful scientific outreach and to push borders of existing formats with the overall aim of developing a better understanding of climate change and our planet

Hampered motility promotes the evolution of wrinkly phenotype in Bacillus subtilis

Abstract Background Selection for a certain trait in microbes depends on the genetic background of the strain and the selection pressure of the environmental conditions acting on the cells. In contrast to the sessile state in the biofilm, various bacterial cells employ flagellum-dependent motility under planktonic conditions suggesting that the two phenotypes are mutually exclusive. However, flagellum dependent motility facilitates the prompt establishment of floating biofilms on the air-medium interface, called pellicles. Previously, pellicles of B. subtilis were shown to be preferably established by motile cells, causing a reduced fitness of non-motile derivatives in the presence of the wild type strain. Results Here, we show that lack of active flagella promotes the evolution of matrix overproducers that can be distinguished by the characteristic wrinkled colony morphotype. The wrinkly phenotype is associated with amino acid substitutions in the master repressor of biofilm-related genes, SinR. By analyzing one of the mutations, we show that it alters the tetramerization and DNA binding properties of SinR, allowing an increased expression of the operon responsible for exopolysaccharide production. Finally, we demonstrate that the wrinkly phenotype is advantageous when cells lack flagella, but not in the wild type background. Conclusions Our experiments suggest that loss of function phenotypes could expose rapid evolutionary adaptation in bacterial biofilms that is otherwise not evident in the wild type strains

Effects of climate change on Southern Ocean phytoplankton ecophysiology

In many regions of the Southern Ocean, surface concentrations of the trace metal iron are very low. Iron is an essential nutrient, required for numerous metabolic pathways in phytoplankton cells. Atmospheric dust is an important source for iron input into the ocean. An insufficient supply of iron can lead to reduced growth and alterations in the photophysiology. Therefore, iron is a key factor in controlling Antarctic phytoplankton productivity and species composition. However, in experiments looking at the effects of iron on phytoplankton physiology, iron is commonly added as iron chloride and not in the form of dust. This PhD project will focus on the effects of inorganic iron in comparison to iron-containing dust as iron sources in combination with current and future elevated CO2 concentrations on Southern Ocean phytoplankton ecology and physiology. Rising CO2 concentrations in the atmosphere will reduce the pH of the world’s oceans. Ocean acidification will affect Southern Ocean phytoplankton by potentially altering the availability of iron. In order to study the impact of different climate change scenarios on Southern Ocean phytoplankton, laboratory experiments with selected species as well as shipboard experiments with natural phytoplankton assemblages during an expedition to the Southern Ocean will be conducted

Iron and manganese co-limit growth of the Southern Ocean diatom Chaetoceros debilis

In some parts of the Southern Ocean (SO), even though low surface concentrations of iron (Fe) and manganese (Mn) indicate FeMn co-limitation, we still lack an understanding on how Mn and Fe availability influences SO phytoplankton ecophysiology. Therefore, this study investigated the effects of Fe and Mn limitation alone as well as their combination on growth, photophysiology and particulate organic carbon production of the bloom-forming Antarctic diatom Chaetoceros debilis. Our results clearly show that growth, photochemical efficiency and carbon production of C. debilis were co-limited by Fe and Mn as highest values were only reached when both nutrients were provided. Even though Mn-deficient cells had higher photochemical efficiencies than Fe-limited ones, they, however, displayed similar low growth and POC production rates, indicating that Mn limitation alone drastically impeded the cell’s performance. These results demonstrate that similar to low Fe concentrations, low Mn availability inhibits growth and carbon production of C. debilis. As a result from different species-specific trace metal requirements, SO phytoplankton species distribution and productivity may therefore not solely depend on the input of Fe alone, but also critically on Mn acting together as important drivers of SO phytoplankton ecology and biogeochemistry