TY  - JOUR
A1  - König, Kerstin
A1  - Zundel, Petra
A1  - Krimmer, Elena
A1  - König, Christian
A1  - Pollmann, Marie
A1  - Gottlieb, Yuval
A1  - Steidle, Johannes L. M.
T1  - Reproductive isolation due to prezygotic isolation and postzygotic cytoplasmic incompatibility in parasitoid wasps
JF  - Ecology and Evolution
N2  - The reproductive barriers that prevent gene flow between closely related species are a major topic in evolutionary research. Insect clades with parasitoid lifestyle are among the most species-rich insects and new species are constantly described, indicating that speciation occurs frequently in this group. However, there are only very few studies on speciation in parasitoids. We studied reproductive barriers in two lineages of Lariophagus distinguendus (Chalcidoidea: Hymenoptera), a parasitoid wasp of pest beetle larvae that occur in human environments. One of the two lineages occurs in households preferably attacking larvae of the drugstore beetle Stegobium paniceum (“DB-lineage”), the other in grain stores with larvae of the granary weevil Sitophilus granarius as main host (“GW-lineage”). Between two populations of the DB-lineage, we identified slight sexual isolation as intraspecific barrier. Between populations from both lineages, we found almost complete sexual isolation caused by female mate choice, and postzygotic isolation, which is partially caused by cytoplasmic incompatibility induced by so far undescribed endosymbionts which are not Wolbachia or Cardinium. Because separation between the two lineages is almost complete, they should be considered as separate species according to the biological species concept. This demonstrates that cryptic species within parasitoid Hymenoptera also occur in Central Europe in close contact to humans.
KW  - cytoplasmic incompatibility
KW  - endosymbiotic bacteria
KW  - Lariophagus distinguendus
KW  - parasitoid wasps
KW  - sexual isolation
KW  - speciation
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222796
VL  - 9
ER  - 
TY  - JOUR
A1  - Hartke, Juliane
A1  - Sprenger, Philipp P.
A1  - Sahm, Jacqueline
A1  - Winterberg, Helena
A1  - Orivel, Jérôme
A1  - Baur, Hannes
A1  - Beuerle, Till
A1  - Schmitt, Thomas
A1  - Feldmeyer, Barbara
A1  - Menzel, Florian
T1  - Cuticular hydrocarbons as potential mediators of cryptic species divergence in a mutualistic ant association
JF  - Ecology and Evolution
N2  - Upon advances in sequencing techniques, more and more morphologically identical organisms are identified as cryptic species. Often, mutualistic interactions are proposed as drivers of diversification. Species of the neotropical parabiotic ant association between Crematogaster levior and Camponotus femoratus are known for highly diverse cuticular hydrocarbon (CHC) profiles, which in insects serve as desiccation barrier but also as communication cues. In the present study, we investigated the association of the ants’ CHC profiles with genotypes and morphological traits, and discovered cryptic species pairs in both genera. To assess putative niche differentiation between the cryptic species, we conducted an environmental association study that included various climate variables, canopy cover, and mutualistic plant species. Although mostly sympatric, the two Camponotus species seem to prefer different climate niches. However in the two Crematogaster species, we could not detect any differences in niche preference. The strong differentiation in the CHC profiles may thus suggest a possible role during speciation itself either by inducing assortative mating or by reinforcing sexual selection after the speciation event. We did not detect any further niche differences in the environmental parameters tested. Thus, it remains open how the cryptic species avoid competitive exclusion, with scope for further investigations.
KW  - environmental association
KW  - integrative taxonomy
KW  - niche differentiation
KW  - population structure
KW  - sexual selection
KW  - speciation
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227857
VL  - 9
ER  - 
TY  - JOUR
A1  - Kendall, Liam K.
A1  - Rader, Romina
A1  - Gagic, Vesna
A1  - Cariveau, Daniel P.
A1  - Albrecht, Matthias
A1  - Baldock, Katherine C. R.
A1  - Freitas, Breno M.
A1  - Hall, Mark
A1  - Holzschuh, Andrea
A1  - Molina, Francisco P.
A1  - Morten, Joanne M.
A1  - Pereira, Janaely S.
A1  - Portman, Zachary M.
A1  - Roberts, Stuart P. M.
A1  - Rodriguez, Juanita
A1  - Russo, Laura
A1  - Sutter, Louis
A1  - Vereecken, Nicolas J.
A1  - Bartomeus, Ignasi
T1  - Pollinator size and its consequences: Robust estimates of body size in pollinating insects
JF  - Ecology and Evolution
N2  - Body size is an integral functional trait that underlies pollination-related ecological processes, yet it is often impractical to measure directly. Allometric scaling laws have been used to overcome this problem. However, most existing models rely upon small sample sizes, geographically restricted sampling and have limited applicability for non-bee taxa. Allometric models that consider biogeography, phylogenetic relatedness, and intraspecific variation are urgently required to ensure greater accuracy. We measured body size as dry weight and intertegular distance (ITD) of 391 bee species (4,035 specimens) and 103 hoverfly species (399 specimens) across four biogeographic regions: Australia, Europe, North America, and South America. We updated existing models within a Bayesian mixed-model framework to test the power of ITD to predict interspecific variation in pollinator dry weight in interaction with different co-variates: phylogeny or taxonomy, sexual dimorphism, and biogeographic region. In addition, we used ordinary least squares regression to assess intraspecific dry weight ~ ITD relationships for ten bees and five hoverfly species. Including co-variates led to more robust interspecific body size predictions for both bees and hoverflies relative to models with the ITD alone. In contrast, at the intraspecific level, our results demonstrate that the ITD is an inconsistent predictor of body size for bees and hoverflies. The use of allometric scaling laws to estimate body size is more suitable for interspecific comparative analyses than assessing intraspecific variation. Collectively, these models form the basis of the dynamic R package, “pollimetry,” which provides a comprehensive resource for allometric pollination research worldwide.
KW  - Apoidea
KW  - biogeography
KW  - body size
KW  - dry weight
KW  - pollimetry
KW  - pollination
KW  - predictive models
KW  - R package
KW  - Syrphidae
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325705
VL  - 9
ER  - 
TY  - JOUR
A1  - Hillaert, Jasmijn
A1  - Hovestadt, Thomas
A1  - Vandegehuchte, Martijn L.
A1  - Bonte, Dries
T1  - Size-dependent movement explains why bigger is better in fragmented landscapes
JF  - Ecology and Evolution
N2  - Body size is a fundamental trait known to allometrically scale with metabolic rate and therefore a key determinant of individual development, life history, and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect consumer body size distributions. Our aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size-dependent and size-independent consumer movement by applying a mechanistic, individual-based resource–consumer model. We also assessed the consequences of altered body size distributions for important ecosystem traits such as resource abundance and consumer stability. Finally, we determined those factors that explain most variation in size distributions. We demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances if the movement is size-dependent. When including size-dependent movement, intermediate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is maximized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size-dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass is lowest when isolation and resource growth are high. Finally, we highlight that size-dependent movement is of vital importance for the survival of populations or communities within highly fragmented landscapes. Our results demonstrate that considering size-dependent movement is essential to understand how habitat fragmentation and resource growth shape body size distributions—and the resulting metapopulation or metacommunity dynamics—of consumers.
KW  - allometric scaling
KW  - body size distributions;
KW  - eco-evolutionary dynamics
KW  - habitat fragmentation
KW  - isolation
KW  - metabolic theory
KW  - optimal size
KW  - size-dependent movement
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-320322
VL  - 8
ER  - 
TY  - JOUR
A1  - Stein, Katharina
A1  - Stenchly, Kathrin
A1  - Coulibaly, Drissa
A1  - Pauly, Alain
A1  - Dimobe, Kangbeni
A1  - Steffan-Dewenter, Ingolf
A1  - Konaté, Souleymane
A1  - Goetze, Dethardt
A1  - Porembski, Stefan
A1  - Linsenmair, K. Eduard
T1  - Impact of human disturbance on bee pollinator communities in savanna and agricultural sites in Burkina Faso, West Africa
JF  - Ecology and Evolution
N2  - All over the world, pollinators are threatened by land-use change involving degradation of seminatural habitats or conversion into agricultural land. Such disturbance often leads to lowered pollinator abundance and/or diversity, which might reduce crop yield in adjacent agricultural areas. For West Africa, changes in bee communities across disturbance gradients from savanna to agricultural land are mainly unknown. In this study, we monitored for the impact of human disturbance on bee communities in savanna and crop fields. We chose three savanna areas of varying disturbance intensity (low, medium, and high) in the South Sudanian zone of Burkina Faso, based on land-use/land cover data via Landsat images, and selected nearby cotton and sesame fields. During 21 months covering two rainy and two dry seasons in 2014 and 2015, we captured bees using pan traps. Spatial and temporal patterns of bee species abundance, richness, evenness and community structure were assessed. In total, 35,469 bee specimens were caught on 12 savanna sites and 22 fields, comprising 97 species of 32 genera. Bee abundance was highest at intermediate disturbance in the rainy season. Species richness and evenness did not differ significantly. Bee communities at medium and highly disturbed savanna sites comprised only subsets of those at low disturbed sites. An across-habitat spillover of bees (mostly abundant social bee species) from savanna into crop fields was observed during the rainy season when crops are mass-flowering, whereas most savanna plants are not in bloom. Despite disturbance intensification, our findings suggest that wild bee communities can persist in anthropogenic landscapes and that some species even benefitted disproportionally. West African areas of crop production such as for cotton and sesame may serve as important food resources for bee species in times when resources in the savanna are scarce and receive at the same time considerable pollination service.
KW  - bee communities
KW  - cotton
KW  - sesame
KW  - species spillover
KW  - sub-Saharan Africa
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239999
VL  - 8
ER  - 
TY  - JOUR
A1  - Minden, Vanessa
A1  - Schnetger, Bernhard
A1  - Pufal, Gesine
A1  - Leonhardt, Sara D.
T1  - Antibiotic-induced effects on scaling relationships and on plant element contents in herbs and grasses
JF  - Ecology and Evolution
N2  - Plant performance is correlated with element concentrations in plant tissue, which may be impacted by adverse chemical soil conditions. Antibiotics of veterinary origin can adversely affect plant performance. They are released to agricultural fields via grazing animals or manure, taken up by plants and may be stored, transformed or sequestered by plant metabolic processes. We studied the potential effects of three antibiotics (penicillin, sulfadiazine, and tetracycline) on plant element contents (macro- and microelements). Plant species included two herb species (Brassica napus and Capsella bursa-pastoris) and two grass species (Triticum aestivum and Apera spica-venti), representing two crop species and two noncrop species commonly found in field margins, respectively. Antibiotic concentrations were chosen as to reflect in vivo situations, that is, relatively low concentrations similar to those detected in soils. In a greenhouse experiment, plants were raised in soil spiked with antibiotics. After harvest, macro- and microelements in plant leaves, stems, and roots were determined (mg/g). Results indicate that antibiotics can affect element contents in plants. Penicillin exerted the greatest effect both on element contents and on scaling relationships of elements between plant organs. Roots responded strongest to antibiotics compared to stems and leaves. We conclude that antibiotics in the soil, even in low concentrations, lead to low-element homeostasis, altering the scaling relationships between roots and other plant organs, which may affect metabolic processes and ultimately the performance of a plant.
KW  - antibiotics
KW  - homeostasis
KW  - scaling relationships
KW  - standardized major axis regression
KW  - tissue nutrient contents
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224094
VL  - 8
ER  - 
TY  - JOUR
A1  - Schubert, Frank K.
A1  - Hagedorn, Nicolas
A1  - Yoshii, Taishi
A1  - Helfrich-Förster, Charlotte
A1  - Rieger, Dirk
T1  - Neuroanatomical details of the lateral neurons of Drosophila melanogaster support their functional role in the circadian system
JF  - Journal of Comparative Neurology
N2  - Drosophila melanogaster is a long-standing model organism in the circadian clock research. A major advantage is the relative small number of about 150 neurons, which built the circadian clock in Drosophila. In our recent work, we focused on the neuroanatomical properties of the lateral neurons of the clock network. By applying the multicolor-labeling technique Flybow we were able to identify the anatomical similarity of the previously described E2 subunit of the evening oscillator of the clock, which is built by the 5th small ventrolateral neuron (5th s-LNv) and one ITP positive dorsolateral neuron (LNd). These two clock neurons share the same spatial and functional properties. We found both neurons innervating the same brain areas with similar pre- and postsynaptic sites in the brain. Here the anatomical findings support their shared function as a main evening oscillator in the clock network like also found in previous studies. A second quite surprising finding addresses the large lateral ventral PDF-neurons (l-LNvs). We could show that the four hardly distinguishable l-LNvs consist of two subgroups with different innervation patterns. While three of the neurons reflect the well-known branching pattern reproduced by PDF immunohistochemistry, one neuron per brain hemisphere has a distinguished innervation profile and is restricted only to the proximal part of the medulla-surface. We named this neuron “extra” l-LNv (l-LNvx). We suggest the anatomical findings reflect different functional properties of the two l-LNv subgroups.
KW  - circadian clock neurons
KW  - Drosophila melanogaster
KW  - flybow
KW  - morphology
KW  - RRID: AB_760350
KW  - RRID: AB_2315460
KW  - RRID: AB_2314242
KW  - RRID: AB_2315311
KW  - RRID: AB_2314041
KW  - RRID: AB_300798
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234477
VL  - 526
ER  - 
TY  - JOUR
A1  - Flunkert, Julia
A1  - Maierhofer, Anna
A1  - Dittrich, Marcus
A1  - Müller, Tobias
A1  - Horvath, Steve
A1  - Nanda, Indrajit
A1  - Haaf, Thomas
T1  - Genetic and epigenetic changes in clonal descendants of irradiated human fibroblasts
JF  - Experimental Cell Research
N2  - To study delayed genetic and epigenetic radiation effects, which may trigger radiation-induced carcinogenesis, we have established single-cell clones from irradiated and non-irradiated primary human fibroblasts. Stable clones were endowed with the same karyotype in all analyzed metaphases after 20 population doublings (PDs), whereas unstable clones displayed mosaics of normal and abnormal karyotypes. To account for variation in radiation sensitivity, all experiments were performed with two different fibroblast strains. After a single X-ray dose of 2 Gy more than half of the irradiated clones exhibited radiation-induced genome instability (RIGI). Irradiated clones displayed an increased rate of loss of chromosome Y (LOY) and copy number variations (CNVs), compared to controls. CNV breakpoints clustered in specific chromosome regions, in particular 3p14.2 and 7q11.21, coinciding with common fragile sites. CNVs affecting the FHIT gene in FRA3B were observed in independent unstable clones and may drive RIGI. Bisulfite pyrosequencing of control clones and the respective primary culture revealed global hypomethylation of ALU, LINE-1, and alpha-satellite repeats as well as rDNA hypermethylation during in vitro ageing. Irradiated clones showed further reduced ALU and alpha-satellite methylation and increased rDNA methylation, compared to controls. Methylation arrays identified several hundred differentially methylated genes and several enriched pathways associated with in vitro ageing. Methylation changes in 259 genes and the MAP kinase signaling pathway were associated with delayed radiation effects (after 20 PDs). Collectively, our results suggest that both genetic (LOY and CNVs) and epigenetic changes occur in the progeny of exposed cells that were not damaged directly by irradiation, likely contributing to radiation-induced carcinogenesis. We did not observe epigenetic differences between stable and unstable irradiated clones. The fact that the DNA methylation (DNAm) age of clones derived from the same primary culture varied greatly suggests that DNAm age of a single cell (represented by a clone) can be quite different from the DNAm age of a tissue. We propose that DNAm age reflects the emergent property of a large number of individual cells whose respective DNAm ages can be highly variable.
KW  - copy number variation (CNV)
KW  - delayed radiation effects
KW  - DNA methylation (DNAm) age
KW  - global DNA methylation
KW  - loss of chromosome Y (LOY);
KW  - methylation array analysis
KW  - radiation-induced genome instability (RIGI)
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228177
VL  - 370
ER  - 
TY  - JOUR
A1  - Baluapuri, Apoorva
A1  - Hofstetter, Julia
A1  - Dudvarski Stankovic, Nevenka
A1  - Endres, Theresa
A1  - Bhandare, Pranjali
A1  - Vos, Seychelle Monique
A1  - Adhikari, Bikash
A1  - Schwarz, Jessica Denise
A1  - Narain, Ashwin
A1  - Vogt, Markus
A1  - Wang, Shuang-Yan
A1  - Düster, Robert
A1  - Jung, Lisa Anna
A1  - Vanselow, Jens Thorsten
A1  - Wiegering, Armin
A1  - Geyer, Matthias
A1  - Maric, Hans Michael
A1  - Gallant, Peter
A1  - Walz, Susanne
A1  - Schlosser, Andreas
A1  - Cramer, Patrick
A1  - Eilers, Martin
A1  - Wolf, Elmar
T1  - MYC Recruits SPT5 to RNA Polymerase II to Promote Processive Transcription Elongation
JF  - Molecular Cell
N2  - The MYC oncoprotein binds to promoter-proximal regions of virtually all transcribed genes and enhances RNA polymerase II (Pol II) function, but its precise mode of action is poorly understood. Using mass spectrometry of both MYC and Pol II complexes, we show here that MYC controls the assembly of Pol II with a small set of transcription elongation factors that includes SPT5, a subunit of the elongation factor DSIF. MYC directly binds SPT5, recruits SPT5 to promoters, and enables the CDK7-dependent transfer of SPT5 onto Pol II. Consistent with known functions of SPT5, MYC is required for fast and processive transcription elongation. Intriguingly, the high levels of MYC that are expressed in tumors sequester SPT5 into non-functional complexes, thereby decreasing the expression of growth-suppressive genes. Altogether, these results argue that MYC controls the productive assembly of processive Pol II elongation complexes and provide insight into how oncogenic levels of MYC permit uncontrolled cellular growth.
KW  - MYC
KW  - SPT5
KW  - SUPT5H
KW  - SPT6
KW  - RNA polymerase II
KW  - transcription
KW  - elongation rate
KW  - processivity
KW  - directionality
KW  - tumorigenesis
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221438
VL  - 74
ER  - 
TY  - JOUR
A1  - Göttlich, Claudia
A1  - Kunz, Meik
A1  - Zapp, Cornelia
A1  - Nietzer, Sarah L.
A1  - Walles, Heike
A1  - Dandekar, Thomas
A1  - Dandekar, Gudrun
T1  - A combined tissue-engineered/in silico signature tool patient stratification in lung cancer
JF  - Molecular Oncology
N2  - Patient-tailored therapy based on tumor drivers is promising for lung cancer treatment. For this, we combined in vitro tissue models with in silico analyses. Using individual cell lines with specific mutations, we demonstrate a generic and rapid stratification pipeline for targeted tumor therapy. We improve in vitro models of tissue conditions by a biological matrix-based three-dimensional (3D) tissue culture that allows in vitro drug testing: It correctly shows a strong drug response upon gefitinib (Gef) treatment in a cell line harboring an EGFR-activating mutation (HCC827), but no clear drug response upon treatment with the HSP90 inhibitor 17AAG in two cell lines with KRAS mutations (H441, A549). In contrast, 2D testing implies wrongly KRAS as a biomarker for HSP90 inhibitor treatment, although this fails in clinical studies. Signaling analysis by phospho-arrays showed similar effects of EGFR inhibition by Gef in HCC827 cells, under both 2D and 3D conditions. Western blot analysis confirmed that for 3D conditions, HSP90 inhibitor treatment implies different p53 regulation and decreased MET inhibition in HCC827 and H441 cells. Using in vitro data (western, phospho-kinase array, proliferation, and apoptosis), we generated cell line-specific in silico topologies and condition-specific (2D, 3D) simulations of signaling correctly mirroring in vitro treatment responses. Networks predict drug targets considering key interactions and individual cell line mutations using the Human Protein Reference Database and the COSMIC database. A signature of potential biomarkers and matching drugs improve stratification and treatment in KRAS-mutated tumors. In silico screening and dynamic simulation of drug actions resulted in individual therapeutic suggestions, that is, targeting HIF1A in H441 and LKB1 in A549 cells. In conclusion, our in vitro tumor tissue model combined with an in silico tool improves drug effect prediction and patient stratification. Our tool is used in our comprehensive cancer center and is made now publicly available for targeted therapy decisions.
KW  - 3D lung tumor model
KW  - Boolean signaling network
KW  - chemoresistance
KW  - HSP90 inhibitor
KW  - insilico drug screening too
KW  - KRAS mutation signature
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233137
VL  - 12
ER  -