Der Verlust circalunarer Rhythmen in arktischen und gezeitenlosen Lebensräumen: Genomische Untersuchungen in lunar-arrhythmische Populationen von Clunio marinus

Biological rhythms are adaptations to periodically changing environmental conditions. The non-biting midge Clunio marinus (Diptera: Chironomidae) is known for the link between its reproduction and the tidal regime. The short-lived adults emerge when most of the intertidal habitat is exposed. C. marinus populations at the European Atlantic coast are locally adapted to the day time and lunar phase of the spring low tides on days around the full moon and new moon. While the circadian rhythm is controlled by a transcriptional-translational feedback loop, the molecular workings of the circalunar rhythm are not understood yet. Populations in the Baltic Sea have adapted to lay the egg clutches in the open sea due to the lack of tides. This allowed for lunar-arrhythmic emergence throughout the entire mating season. In arctic habitats of the Atlantic coast tides are still present. During the mating season the sun illuminates the habitat around the clock, preventing the perception of moon light. Individuals changed from circadian-circalunar-controlled emergence to circatidal rhythms in polar day conditions. My thesis takes a large step towards the understanding of the circalunar rhythms in C. marinus by comparing rhythmic to naturally occurring arrhythmic populations. I generated a comprehensive genomic resource for geographically and ecologically distant populations of the same species. Genomic screens for ecotype-adaptive loci identified a putative involvement of circadian clock genes in circalunar rhythms of C. marinus. A crossing experiment between rhythmic and arrhythmic ecotypes of sympatric populations hinted towards the involvement of multiple loci across the genome in lunar-rhythmicity. The addition of further genetic markers could identify a link of the circadian clock to circalunar rhythms as well as unravel the maintenance of sympatric ecotypes

Solving a 50 year mystery of a missing OPA1 mutation: more insights from the first family diagnosed with autosomal dominant optic atrophy

Background: Up to the 1950s, there was an ongoing debate about the diversity of hereditary optic neuropathies, in particular as to whether all inherited optic atrophies can be ascribed to Leber's hereditary optic neuropathy (LHON) or represent different disease entities. In 1954 W. Jaeger published a detailed clinical and genealogical investigation of a large family with explicit autosomal dominant segregation of optic atrophy thus proving the existence of a discrete disease different from LHON, which is nowadays known as autosomal dominant optic atrophy (ADOA). Since the year 2000 ADOA is associated with genomic mutations in the OPA1 gene, which codes for a protein that is imported into mitochondria where it is required for mitochondrial fusion. Interestingly enough, the underlying mutation in this family has not been identified since then. Results: We have reinvestigated this family with the aim to identify the mutation and to further clarify the underlying pathomechanism. Patients showed a classical non-syndromic ADOA. The long term deterioration in vision in the two teenagers examined 50 years later is of particular note 5/20 to 6/120. Multiplex ligation probe amplification revealed a duplication of the OPA1 exons 7-9 which was confirmed by long distance PCR and cDNA analysis, resulting in an in-frame duplication of 102 amino acids. Segregation was verified in 53 available members of the updated pedigree and a penetrance of 88% was calculated. Fibroblast cultures from skin biopsies were established to assess the mitochondrial network integrity and to qualitatively and quantitatively study the consequences of the mutation on transcript and protein level. Fibroblast cultures demonstrated a fragmented mitochondrial network. Processing of the OPA1 protein was altered. There was no correlation of the OPA1 transcript levels and the OPA1 protein levels in the fibroblasts. Intriguingly an overall decrease of mitochondrial proteins was observed in patients' fibroblasts, while the OPA1 transcript levels were elevated. Conclusions: The thorough study of this family provides a detailed clinical picture accompanied by a molecular investigation of patients' fibroblasts. Our data show a classic OPA1-associated non-syndromic ADOA segregating in this family. Cell biological findings suggest that OPA1 is regulated by post-translational mechanisms and we would like to hypothesize that loss of OPA1 function might lead to impaired mitochondrial quality control. With the clinical, genetic and cell biological characterisation of a family described already more than 50 years ago, we span more than half a century of research in optic neuropathies

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Dominant optic atrophy, OPA1, and mitochondrial quality control: understanding mitochondrial network dynamics

Abstract Mitochondrial quality control is fundamental to all neurodegenerative diseases, including the most prominent ones, Alzheimer’s Disease and Parkinsonism. It is accomplished by mitochondrial network dynamics – continuous fission and fusion of mitochondria. Mitochondrial fission is facilitated by DRP1, while MFN1 and MFN2 on the mitochondrial outer membrane and OPA1 on the mitochondrial inner membrane are essential for mitochondrial fusion. Mitochondrial network dynamics are regulated in highly sophisticated ways by various different posttranslational modifications, such as phosphorylation, ubiquitination, and proteolytic processing of their key-proteins. By this, mitochondria process a wide range of different intracellular and extracellular parameters in order to adapt mitochondrial function to actual energetic and metabolic demands of the host cell, attenuate mitochondrial damage, recycle dysfunctional mitochondria via the mitochondrial autophagy pathway, or arrange for the recycling of the complete host cell by apoptosis. Most of the genes coding for proteins involved in this process have been associated with neurodegenerative diseases. Mutations in one of these genes are associated with a neurodegenerative disease that originally was described to affect retinal ganglion cells only. Since more and more evidence shows that other cell types are affected as well, we would like to discuss the pathology of dominant optic atrophy, which is caused by heterozygous sequence variants in OPA1, in the light of the current view on OPA1 protein function in mitochondrial quality control, in particular on its function in mitochondrial fusion and cytochrome C release. We think OPA1 is a good example to understand the molecular basis for mitochondrial network dynamics

The importance of DNA barcode choice in biogeographic analyses – a case study on marine midges of the genus Clunio

DNA barcodes are widely used for species identification and biogeographic studies. Here, we compare the use of full mitochondrial genomes versus DNA barcodes and other mitochondrial DNA fragments for biogeographic and ecological analyses. Our dataset comprised 120 mitochondrial genomes from the genus Clunio (Diptera: Chironomidae), comprising five populations from two closely related species (Clunio marinus and Clunio balticus) and three ecotypes. We extracted cytochrome oxidase c subunit I (COI) barcodes and partitioned the mitochondrial genomes into non-overlapping windows of 750 or 1500 bp. Haplotype networks and diversity indices were compared for these windows and full mitochondrial genomes (15.4 kb). Full mitochondrial genomes indicate complete geographic isolation between populations, but do not allow for conclusions on the separation of ecotypes or species. COI barcodes have comparatively few polymorphisms, ideal for species identification, but do not resolve geographic isolation. Many of the similarly sized 750 bp windows have higher nucleotide and haplotype diversity than COI barcodes, but still do not resolve biogeography. Only when increasing the window size to 1500 bp, two windows resolve biogeography reasonably well. Our results suggest that the design and use of DNA barcodes in biogeographic studies must be carefully evaluated for each investigated species.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Resistive switching and voltage induced modulation of tunneling magnetoresistance in nanosized perpendicular organic spin valves

Nanoscale multifunctional perpendicular organic spin valves have been fabricated. The devices based on an La0.7Sr0.3MnO3/Alq3/Co trilayer show resistive switching of up to 4-5 orders of magnitude and magnetoresistance as high as -70% the latter even changing sign when voltage pulses are applied. This combination of phenomena is typically observed in multiferroic tunnel junctions where it is attributed to magnetoelectric coupling between a ferromagnet and a ferroelectric material. Modeling indicates that here the switching originates from a modification of the La0.7Sr0.3MnO3 surface. This modification influences the tunneling of charge carriers and thus both the electrical resistance and the tunneling magnetoresistance which occurs at pinholes in the organic layer

A DIPTERAN'S SUCKER PUNCH: DIVERSE VENOM COMPOSITION OF THE ROBBER FLIES

The family of the robberflies comprises more than 7,000 species, which are distributed all over the world and diversify on around 500 different genera. Even with a first “high quality” robberfly draft genome published in 2017, the phylogeny of this family is still not solved on a satisfying level. Nevertheless, the asilids are one of the most prominent family of flies within the brachycera. As an exception to other groups the larvae and the adults of both sexes are obligate predators. Reports of robberflies preying on huge arthropods are known since the 19th century and first studies showed the presence of venom in this taxon as early as 1850. In general venoms can be seen as key adaptions to ensure evolutionary fitness and survival of a species; often they are complex mixture of proteins, salts and different organic molecules. Single toxins often evolved from proteins with an ancestral physiological function, which were sub- or neofunctionalized during the evolution and now act as a toxin. It is known that robberflies use there needle-like hypo-pharynx to pierce through the cuticle of a prey to inject the potential venom. Besides that, morphological studies showed the presence of two gland systems, called thoracic- and labial gland system, associated with the mouthparts of these flies. The bigger thoracic gland system seems to be present in all robberfly species, while the smaller labial glands seem to vary in form and size and also lack completely in some species. A toxic effect of the toracic gland tissue could already be shown without being able to name compounds of a potential robber fly venom. The presented study combined transcriptomic and proteomic approaches to provide a first insight into the venom composition of the robberfly species Machimus arthtriticus and Eutolmus rufibarbis. Additionally, three-dimensional reconstructed synchrotron based micro computer tomography of the asilids gland systems gives an insight in to the morphological diversity of these systems within the family

Genomic variants causing mitochondrial dysfunction are common in hereditary lower motor neuron disease

Altmuller, Janine/0000-0003-4372-1521WOS:000624460100001PubMed: 33600046Hereditary lower motor neuron diseases (LMND) other than 5q-spinal muscular atrophy (5q-SMA) can be classified according to affected muscle groups. Proximal and distal forms of non-5q-SMA represent a clinically and genetically heterogeneous spectrum characterized by significant overlaps with axonal forms of Charcot-Marie-Tooth (CMT) disease. A consensus for the best approach to molecular diagnosis needs to be reached, especially in light of continuous novel gene discovery and falling costs of next-generation sequencing (NGS). We performed exome sequencing (ES) in 41 families presenting with non-5q-SMA or axonal CMT, 25 of which had undergone a previous negative neuromuscular disease (NMD) gene panel analysis. The total diagnostic yield of ES was 41%. Diagnostic success in the cohort with a previous NMD-panel analysis was significantly extended by ES, primarily due to novel gene associated-phenotypes and uncharacteristic phenotypic presentations. We recommend early ES for individuals with hereditary LMND presenting uncharacteristic or significantly overlapping features. As mitochondrial dysfunction was the underlying pathomechanism in 47% of the solved individuals, we highlight the sensitivity of the anterior horn cell and peripheral nerve to mitochondrial imbalance as well as the necessity to screen for mitochondrial disorders in individuals presenting predominant lower motor neuron symptoms.Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG) [Wi 945/19-1]; Center for Molecular Medicine Cologne [C18]; Clinical Scientist Award; Universitat zu KolnDeutsche Forschungsgemeinschaft, Grant/Award Number: Wi 945/19-1 (B.W.); Center for Molecular Medicine Cologne, Grant/Award Number: C18; Clinical Scientist Award (B.W. and M.K.); Universitat zu Koln, Grant/Award Number: Koln Fortune (N.K.